Permissible vibration level LPDS. Development of recommendations for reducing the influence of vibration on the body of a mechanic in the category of technological installations of the LPDS Perm JSC North-Western Oil Mains. Development of recommendations to reduce the impact of vibration on the body
GOST 30576-98
INTERSTATE STANDARD
Vibration
CENTRIFUGAL PUMPS
NUTRITIONAL THERMAL
POWER PLANTS
Vibration standards and General requirements to carry out measurements
INTERSTATE COUNCIL
ON STANDARDIZATION, METROLOGY AND CERTIFICATION
Minsk
Preface
1 DEVELOPED by the Interstate Technical Committee for Standardization MTK 183 “Vibration and Shock” with the participation of the Ural Thermal Engineering Research Institute (JSC UralVTI) INTRODUCED by the State Standard of Russia2 ACCEPTED by the Interstate Council for Standardization, Metrology and Certification (protocol No. 13 - 98 of May 28, 1998 ) Voted for adoption: 3 Resolution State Committee Russian Federation on Standardization and Metrology dated December 23, 1999 No. 679-st interstate standard GOST 30576-98 was put into effect directly as a state standard of the Russian Federation from July 1, 20004 INTRODUCED FOR THE FIRST TIME
INTERSTATE STANDARD
Vibration
CENTRIFUGAL FEED PUMPS FOR THERMAL POWER POWER PLANTS
Vibration standards and general requirements for measurements
Mechanical vibration. Centrifugal feed pumps for thermal stations.
Evaluation of machine vibration and requirements for the measurement of vibration
Date of introduction 2000-07-01
1 area of use
This standard applies to centrifugal feed pumps with a power of more than 10 MW driven by a steam turbine and an operating speed from 50 to 100 s -1. The standard sets standards for permissible vibrations of bearing supports of centrifugal feed pumps that are in operation and put into operation after installation or repairs, as well as general requirements for measurements. The standard does not apply to turbine drive supports for pumps.2 Normative references
This standard uses references to the following standards: GOST ISO 2954-97 Vibration of machines with reciprocating and rotary motion. Requirements for measuring instruments GOST 23269-78 Stationary steam turbines. Terms and definitions GOST 24346-80 Vibration. Terms and Definitions3 Definitions
This standard uses terms with corresponding definitions in accordance with GOST 23269 and GOST 24346.4 Vibration standards
4.1 The standard vibration parameter is set to the root mean square value of the vibration velocity in the operating frequency band from 10 to 1000 Hz during stationary operation of the pump. 4.2 The vibration state of feed pumps is assessed by highest value any vibration component measured in accordance with 5.2.1 in the operating range for feed water flow and pressure. 4.3 Acceptance of feed pumps from installation and overhaul is allowed with vibration of bearing supports not exceeding 7.1 mm s -1 throughout the entire operating range pump operation and for the total duration of operation determined by the acceptance rules. 4.4 Long-term operation of centrifugal feed pumps is allowed with vibration of the bearing supports not exceeding 11.2 mm s -1 .4.5 When vibration of the bearing supports exceeds the norm established in 4.4, a warning alarm must be triggered and measures must be taken to bring the vibration to the required level level for a period of no more than 30 days. 4.6 Operation of feed pumps with vibration above 18.0 mm s -1 is not allowed.5 General requirements for measurements
5.1 Measuring equipment
5.1.1 Vibration of feed pumps is measured and recorded using stationary equipment for continuous monitoring of vibration of bearing supports, meeting the requirements of GOST ISO 2954.5.1.2 Before installing stationary equipment for continuous monitoring of vibration of pumps, it is allowed to use portable instruments whose metrological characteristics comply with the requirements of GOST ISO 2954.5.2 Taking measurements
5.2.1 Vibration is measured for all bearing supports in three mutually perpendicular directions: vertical, horizontal transverse and horizontal axial with respect to the axis of the feed pump shaft. 5.2.2 Horizontal transverse and horizontal axial vibration components are measured at the level of the axis of the pump shaft unit against the middle of the length of the support liner on one side. Sensors for measuring the horizontal transverse and horizontal axial components of vibration are attached to the bearing housing or to special sites that do not have resonances in the frequency range from 10 to 1000 Hz and are rigidly connected to the support, in direct proximity to the horizontal connector.5.2.3 The vertical component of vibration is measured on the top of the bearing cover above the middle of the length of its liner.5.2.4 When using portable vibration equipment, the frequency of vibration monitoring is established local instructions operating instructions depending on the vibration state of the pump.5.3 Registration of measurement results
5.3.1 The results of vibration measurements when putting a pumping unit into operation after installation or major repairs are documented in an acceptance certificate, which indicates: - the date of measurement, the names of the persons and the names of the organizations carrying out the measurements; - the operating parameters of the pumping unit at which the measurements were taken (inlet and outlet pressure, flow, rotation speed, feed water temperature, etc.); - diagram of vibration measurement points; - name of measuring instruments and date of their verification; - vibration value of bearing supports obtained during measurement. 5.3.2 During the operation of the pumping unit, the vibration measurement results are recorded by instruments and entered into the turbine unit operator’s operational record. In this case, the operating parameters of the turbine unit (load and fresh steam consumption) must be recorded. Key words: centrifugal feed pumps, standards, bearing supports, vibration, measurements, controlThe diploma project contains 109 pp., 24 figures, 16 tables, 9 sources used, 6 appendices.
AUTOMATION OF MAIN PUMPING UNIT NM1250-260, SENSOR, SIGNAL, ACS OF THE MODICON TSX QUANTUM SERIES, VIBRATION CONTROL, VIBRATION CONTROL SYSTEMS
The object of the study is the main pumping unit NM 1250-260, used in the Cherkasy LPDS.
During the research, an analysis of the existing level of automation of the unit was carried out, and the need to modernize its control system was substantiated.
The purpose of the work is to develop a control program for the Modicon TSX Quantum PLC from Schneider Electric.
As a result of the research, an automation system for the main pumping unit was developed based on modern software and hardware. As software The project uses the ST language of the ISaGRAF program.
Experimental design and technical and economic indicators indicate an increase in the operating efficiency of the modernized control system of the main pumping unit.
Degree of implementation the results obtained were applied in the “Cascade” vibration control system.
The effectiveness of implementation is based on increasing the reliability of the MNA automation system, which is confirmed by calculating the economic effect for the billing period.
Definitions, symbols and abbreviations…………………………………… 6
Introduction…………………………………………………………………………………….. 7
1 Linear production dispatch station “Cherkassy”…. 9 1.1 Brief description of the linear production control station “Cherkassy”……………………………………………………………………………….. 9
1.2 Characteristics of technological equipment…………………………. 9
1.3 Characteristics of technological premises…………………………… 12 1.4 Operating modes of LPDS “Cherkassy”……………………………………. 13 1.5 Main pumping unit…………………………………………. 16 1.6 Piping of LPDS “Cherkassy” pumps………………………………………………………. 18
1.7 Analysis of the existing automation scheme for LPDS “Cherkassy”……... 19
2 Patent development………………………………………………………... 22
3 Automation of LPDS “Cherkassy”………………………………………… 27
3.1 Automation of the main pumping unit…………………….. 27
3.2 Anti emergency protection……………………………………… 33
3.3 Process control system based on Modicon TSX Quantum controllers………………….. 35
3.4 Structural scheme Process control system based on the Quantum system………………… 39
3.5 Devices included in the system………………………………….. 42
3.6 Sensors and technical means automation…………………………. 48
4 Selecting the MNA vibration control system………………………………………... 54 4.1 Vibration monitoring equipment (VMC)…………………………. 54
4.2 Vibration monitoring equipment “Cascade”….…………………………….. 56
4.3 Development of a pumping unit control program………….…….. 64
4.4 Instrumental system for programming industrial controllers…………………………………………………………………………………. 65
4.5 Description of the ST language………………………………………………………. 67
4.6 Creation of a project and programs in the ISaGRAF system………………………. 71
4.7 Programming the controller……………………………………………………... 73
4.8 Algorithm for signaling and control of the pumping unit…………...... 74
4.9 Results of the program…….…………………..………………………... 77
5 Occupational health and safety at the main pumping station of the Ufa-Western Direction MNPP………………………………………………………………… 80
5.1 Analysis of potential hazards and industrial hazards... 80
5.2 Safety measures during the operation of LPDS “Cherkassy” facilities………………………………………………………………………………………… 85
5.3 Industrial sanitation measures……………………………… 86
5.4 Measures for fire safety………………………………… 89
5.5 Calculation of foam extinguishing installation and fire water supply……… 91
6 Assessment of the economic efficiency of automation of the line-production control station “Cherkassy”………………………. 96
6.1 Main sources of efficiency improvement……………………… 97 6.2 Methodology for calculating economic efficiency……………………… 97
6.3 Calculation of economic effect………………………………………………………. 99
Conclusion……………………………………………………………………………… 107
List of sources used………………………………………………………... 109
Appendix A. List of demonstration sheets……………………… 110
Appendix B. Specifications and connection diagrams for power supply modules……………………………………………………………………………………………… 111
Appendix B. Specification of the central processing unit... 114
Appendix D. Specifications of input/output modules………………….. 117
Appendix D. Advantech module specifications………………………... 122
Appendix E. Listing of the control program………………………… 125
DEFINITIONS, NOTATIONS AND ABBREVIATIONS
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Linear production and dispatch station |
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Automated workstations |
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Manual control unit |
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Ufa-Western direction |
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Automatic switching on of reserve |
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Local control center |
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Main pump unit |
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Main oil product pipeline |
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Microprocessor automation system |
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Fire safety standards |
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Oil pumping station |
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Software logic controller |
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Electric motor |
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District control center |
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Dispatcher control and data acquisition |
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Cleaning and Diagnostic Tool |
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Programming language |
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Pressure Wave Smoothing System |
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High voltage circuit breaker |
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Device for communicating with an object |
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Dirt filters |
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CPU |
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Rules for electrical installations |
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Building regulations |
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Occupational Safety Standards System |
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Information processing system |
INTRODUCTION
Automation of technological processes is one of the decisive factors in increasing productivity and improving working conditions. All existing and under construction facilities are equipped with automation equipment.
Transportation of petroleum products is a continuous production that requires close attention to issues of reliable operation, construction and reconstruction of oil pumping facilities, and major repairs of equipment. Currently, the main task of transporting petroleum products is to improve the efficiency and quality of the transport system. To accomplish this task, it is planned to build new and modernize existing oil pipelines, and widely introduce automation, telemechanics and automated control systems for the transport of petroleum products. At the same time, it is necessary to increase the reliability and efficiency of oil pipeline transport.
The automation system of the line production dispatch service (LPDS) is designed to monitor, protect and manage oil pipeline equipment. It must ensure autonomous maintenance of the specified operating mode of the pumping station and its change according to commands from the LPDS operator console and from a higher control level - the district control center (RDP).
The relevance of creating automation of control systems at the Cherkassy LPDS has increased due to the low level of automation, the presence of obsolete relay circuits, low reliability and complexity of maintenance. This requires replacing existing systems with a microprocessor-based automation system.
The goal of the diploma project is: increasing the reliability and survivability of process equipment and automation equipment for LPDS; expansion of functionality; increasing frequency Maintenance and repair of stations.
The objectives of the diploma project are:
- analysis existing system automation of LPDS;
- modernization of the control system for pumping units based on PLC;
Automation is the highest level of production mechanization and is used in the complex of technological process management production processes. It opens up enormous opportunities for increasing labor productivity, rapid growth in the pace of production development, as well as the safety of production processes.
1 Linear production dispatch station "Cherkassy"
1.1 Brief description of the linear production control station "Cherkassy"
LPDS "Cherkassy" of the Ufa production department of OJSC "Uraltransnefteprodukt" was formed in 1957 with the commissioning of the Ufa Petropavlovsk MNPP, pumping station No. 1 and the RVS-5000 tank farm in the amount of 20 pieces with a total capacity of about 57.0 thousand tons. The station was established as the second site of the Cherkassy oil pumping station of the Ufa Regional Oil Pipeline Directorate, which is part of the Directorate of the Ural-Siberian Main Oil Pipelines.
1.2 Characteristics of technological equipment
The technological equipment of LPDS "Cherkassy" includes:
Three main pumps NM 1250-260 for a nominal flow rate of 1250 m/h with a head of 260 m, with electric motors STD 1250/2 with a power of N=1250 kW, n=3000 rpm and one main pump NM 1250-400 for a nominal flow of 1250 m /h with a head of 400 m, with an AZMP-1600 electric motor with a power of N=2000 kW, n=3000 rpm, located in a common shelter and separated by a firewall wall;
Pressure regulation system consisting of three pressure regulators;
Oil system for forced lubrication of pump unit bearings, consisting of two oil pumps, two oil tanks, an accumulating tank, two oil filters, two oil coolers;
System recycling water supply, consisting of two water pumps;
Leak collection and pumping system, consisting of four tanks and two leak pumps;
Ventilation system consisting of supply- exhaust ventilation pump compartments (two supply and two exhaust fans); backup ventilation of the electric motor compartment (one fan is existing, the installation of a second is planned for the future to perform emergency switching on of the reserve (ATS)); supporting ventilation of non-flush chambers (two fans); exhaust ventilation of the pressure regulator chamber (one fan is existing, the installation of a second is planned for the future to perform automatic transfer control); exhaust ventilation of the chamber for pumping out leaks (one fan is existing, the installation of a second one is being considered for the future to perform an automatic transfer system);
Electrically driven valves on process pipelines;
Filter system consisting of a dirt filter and two fine filters;
Power supply system;
Automatic fire extinguishing system.
Pressure regulator chamber protected room: brick walls. There are 3 pressure regulators in this room.
Leakage chamber protected room: brick walls. There are 2 leak pumps in this room.
All actuators providing automatic operation PS must be equipped with electric drives. Pipeline shut-off valves must be equipped with sensors for signaling extreme positions (open, closed). Automated equipment is equipped
devices for installing control sensors and actuators.
The technological diagram of the main pumping station of the Ufa-Western Direction MNPP No. 2 of the LPDS Cherkassy is shown in Figure 1.1.
1.3 Characteristics of technological premises
The general shelter of the pump house consists of a pump compartment and an electric motor compartment, separated by a firewall. The pump compartment room belongs to the explosive zone B-1a in accordance with the Rules for the Construction of Electrical Installations PUE, (class 1 zone according to GOST R 51330.3-99), for fire hazard to category A according to Fire Safety Standards NPB 105-95, for functional hazard to category F5.1 according to Construction Norms and Rules SNiP 21-01-97. The premises are subject to automatic fire extinguishing.
The space in the electric motor compartment does not belong to the explosion hazard zone. In terms of fire hazard, the room of the electric motor compartment belongs to category D. In the electric motor compartment there is an oil receiver, which, in terms of fire hazard, belongs to category B according to NPB 105-95. The oil receiver is subject to automatic fire extinguishing. In terms of functional hazard, the electric motor compartment belongs to category F5.1 according to SNiP 21-01-97.
Pressure regulator chamber protected room: brick walls. There are 3 pressure regulators in this room. The space inside the room belongs to the explosive zone V-1a according to the PUE (class 1 zone according to GOST R 51330.3-99). In terms of functional hazard - category F 5.1 according to SNiP 21-01-97). In terms of fire hazard to category A according to NPB 105-95. The pressure regulator chamber is subject to automatic fire extinguishing. Supply pipe fire extinguishing agent not provided. The automation system provides for the implementation of automatic fire extinguishing of the pressure regulator chamber.
Leakage chamber - protected room: brick walls. There are 2 leak pumps in this room. The space inside the room belongs to the explosive zone B-1a according to the PUE (class 1 zone according to GOST R 51330.3-99), for functional hazard - to category F5.1 according to SNiP 21-01-97, for fire hazard - to category A according to NPB 105-95. There is no fire extinguishing agent supply pipeline. The automation system provides for the implementation of automatic fire extinguishing of the leak pumping chamber.
1.4 Operating modes of LPDS “Cherkassy”
The automation system must provide the following control modes for pumping stations:
- “telemechanical”;
- “not telemechanical.”
The mode is selected from the automated workstation (AW) of the operator-technologist of the Cherkassy LPDS pumping station.
Each chosen mode must exclude the other.
Switching from mode to mode must be carried out without stopping the operating units and the station as a whole.
In the “telemechanical” mode, the following types of telecontrol (TC) are provided from the RDP of the oil product pipeline using the telemechanical system:
Starting and stopping auxiliary systems of the pumping station;
Opening and closing valves at the station entrance and exit;
Start and stop of main pumping units according to the programs for starting and stopping the main unit.
Control of units and systems, including auxiliary systems and valves at the inlet and outlet of the station, via the telemechanics system must be accompanied, in addition to the message about the state (position) of the unit, by the message “Enabled - disabled by the pipeline manager” on the screen of the operator’s workstation and recorded in the event log.
In the “non-telemechanical” mode, control of process valves, booster and main pumping units, units of auxiliary systems of the pumping station is provided using general commands “programmed start”, “programmed stop” of main pumping units and auxiliary equipment.
Table 1.1 shows the technological parameters of the station. Table 1.1 - Technological parameters of operation of LPDS "Cherkassy"
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Parameter |
Meaning |
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Location of the station along the MNPP highway, km |
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Elevation, m |
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Maximum permissible operating pressure at pump discharge (at the manifold, up to the control devices), MPa |
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Maximum permissible operating pressure at the station discharge (after control devices), MPa |
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Minimum and maximum permissible operating pressure at pump intake, MPa |
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Lowest and highest viscosity of petroleum product pumped into the pipeline, mm/s |
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Limit of temperature change of pumped petroleum product from reservoirs to MNPP, C |
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Pump type and purpose |
NM1250-260 No. 1 main NM1250-260 No. 2 main NM1250-400 No. 3 main NM1250-400 No. 4 main |
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Impeller diameter, mm |
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Motor type |
STD-1250/2 No. 1 STD-1250/2 No. 2 STD-1250/2 No. 3 4AZMP- 1600/6000 No. 4 |
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Minimum pressure at station intake, MPa |
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Maximum pressure in MNPP at the station outlet, MPa |
1.5 Main pumping unit
Each MNA contains the following objects: pump, electric motor.
The MNA equipment uses a NM 1250-260 pump and an STD-1250/2 electric motor, and one NM 1250-400 pump with an AZMP-1600 electric motor.
Centrifugal pumps are the main type of injection equipment for pumping oil through main oil product pipelines. They meet the requirements for MPU for pumping significant volumes of oil over long distances. Main pumps must have excess pressure at the inlet. This pressure should prevent the dangerous phenomenon of cavitation, which can occur inside the pump as a result of a decrease in pressure in a fast-moving liquid.
Cavitation consists of the formation of bubbles filled with vapors of the pumped liquid. When these bubbles enter the area high pressure, they collapse, developing huge point pressures. Cavitation leads to rapid wear of supercharger parts and reduces its efficiency. The NM pump used is designed for transporting oil and petroleum products through main pipelines with temperatures from minus 5 to +80C, containing mechanical impurities by volume no more than 0.05% and size no more than 0.02 mm. The pump is horizontal, sectional, multistage, single-casing or double-casing NM, with single-entry impellers, with plain bearings (with forced lubrication), with mechanical end seals, driven by an electric motor.
The pump unit is driven by an explosion-proof STD type electric motor with a power of 1250 kW. It is installed in a common room with the supercharger. The explosion-proof design of the electric motor is achieved by forced air injection by a ventilation system under protective cover drive to maintain excess pressure (preventing the penetration of oil vapor into the engine), as well as the use of an explosion-proof enclosure.
High voltage asynchronous electric motors are also used to drive the pumps. However, when using asynchronous motors with a power from 2.5 to 8.0 MW, it is necessary to install expensive static power capacitors in the pump room (which often fail when the station load and ambient temperature fluctuate), as well as a complex of high-voltage equipment that complicates the power supply circuit.
Synchronous electric motors have better stability indicators compared to asynchronous ones, which is especially important when voltage drops occur in the network.
In terms of cost, synchronous electric motors are usually more expensive than similar asynchronous ones, but they have better energy characteristics, which makes their use efficient. It is believed that the coefficient of performance (COP) of a synchronous motor changes slightly at loads close to the rated power of the motor. At loads ranging from 0.5 to 0.7 rated power, the efficiency of synchronous electric motors decreases significantly. The practice of operating oil pipelines has shown that in conditions of constantly changing loading levels of pipeline systems, it is advisable to use adjustable drives of pumping units. By adjusting the speed of the supercharger impeller, it is possible to smoothly change its hydraulic and energy characteristics, adjusting the operation of the pump to changing loads. DC motors allow speed control by simply changing the resistance (for example, by introducing a rheostat into the motor rotor circuit), but such motors have a relatively narrow control range. AC motors allow speed control by changing the frequency of the supply current (from an industrial frequency of 50 Hz to a higher or lower value, depending on whether the rotor shaft speed needs to be increased or decreased, respectively).
1.6 Piping of LPDS “Cherkassy” pumps
The pumps can be connected in series, in parallel or in a combined way (Figures 1.2 1.4).
Figure 1.2 Sequential piping of pumps
Figure 1.3 Parallel piping of pumps
Figure 1.4 Combined pump piping
A series connection of pumps is used to increase the pressure, and a parallel connection is used to increase the flow of the pumping station LPDS "Cherkassy" includes four main pumping units with electric motors located in a common shelter of the oil pumping station. To increase the pressure at the outlet of the station, the pumps are connected in series (Figure 1.6), so that at the same supply, the pressures created by the pumps are summed up. Pump piping ensures the operation of the LPDS when any of the station units goes into reserve. A gate valve is installed at the suction and discharge of each pump, and a check valve is installed parallel to the pump.
Figure 1.5 Pump piping at the substation
The check valve separating the suction and discharge lines of each pump allows fluid to flow in only one direction. When the pump is running, the pressure acting on the valve flap on the left (discharge pressure) is greater than the pressure acting on this flapper on the right (suction pressure), causing the flapper to be closed and oil flowing through the pump. When the pump is not working, the pressure to the right of the valve damper is greater than the pressure to the left of it, as a result of which the damper is open, and the oil product flows through KO-1 to the next pump, bypassing the idle one.
1.7 Analysis of the existing automation scheme of LPDS "Cherkassy"
Automated equipment is equipped with devices for installing control sensors and actuators.
All actuators are equipped with drives with electrical control signals. The shut-off valves of the external and internal pipelines of the LPDS are equipped with sensors for signaling extreme positions (open, closed).
When implementing an automation system, the following tasks are ensured:
Analysis of technological equipment modes;
Control of technological parameters;
Control and monitoring of valves;
Monitoring the readiness for launch of main and booster pumping units;
Processing limit values of parameters for the main pumping unit;
Control and monitoring of main and booster pumping units;
Control and monitoring of the receiving valve of the main pumping unit;
Adjustment of the control setpoint when starting the main unit;
Setting regulation settings;
Pressure regulation;
Control and monitoring of oil pumps;
Control and monitoring of the supply fan of the pump room;
Control and monitoring of the pump room exhaust fan;
Control and monitoring of the leak pump;
Processing of measured parameters;
Reception and transmission of signals to telemechanics systems.
The status and operating parameters of the LPDS equipment are displayed on the screen of the LPDS operator’s workstation in the form of the following video frames:
General scheme pumping station;
Diagram of individual main units and auxiliary systems;
Energy scheme;
Scheme of adjacent sections of the route.
The LPDS manual control unit (MCU), installed in the control room (CHSU), provides:
Light signaling from:
1) emergency pressure sensors at the inlet, in the manifold and at the outlet of the LPDS;
Fire alarm system channels;
2) channels of gas pollution;
3) collection tank overflow sensor;
4) pumping station flood sensor;
5) alarm relay;
Control command buttons:
Emergency shutdown of LPDS;
Shutdowns of main and pumping units;
Switching on main and pumping units;
Opening and closing the station connection valves.
Currently, with a constant decrease in oil production, the volume of pumped oil is decreasing. In this regard, a system of automatic control of the pumping mode is used. The system is designed to control and regulate pressure at the inlet and outlet of pumping stations of main oil pipelines. The system uses electrically driven control valves to regulate the pressure at the inlet and outlet of oil pipelines by throttling the outlet flow.
2 Patent development
2.1 Selection and justification of the subject of search
The diploma project examines the project for modernizing the automated process control system of the line-production dispatch station LPDS "Cherkassy" of OJSC "Uraltransnefteprodukt".
One of the measured parameters of the pumping unit of the linear production control station is vibration. At LPDS, for these purposes, I propose to use the “Cascade” vibration measurement system, therefore, when conducting a patent search, attention was paid to the search and analysis of piezoelectric sensors for measuring vibration in technological facilities of the oil and gas industry.
2.2 Patent search rules
The patent search was carried out using the USPTU fund using sources of patent documentation of the Russian Federation.
Search depth five years (2007-2011). The search was carried out using the International Patent Classification (IPC) index G01P15/09 “Measurement of acceleration and deceleration; measurement of acceleration pulses using a piezoelectric sensor."
The following sources of patent information were used:
Documents of the reference and retrieval apparatus;
Full descriptions of Russian patents;
Official bulletin of the Russian Agency for Patents and Trademarks.
2.3 Patent search results
The results of viewing sources of patent information are shown in Table 2.1.
Table 2.1 Patent search results
2.4 Analysis of patent search results
The piezoelectric accelerometer according to patent No. 2301424 contains a multilayer package of piezoceramic plates, consisting of three sections. Sections include groups of three plates. The outer plates in the group are equipped with diametrical grooves filled with switching buses. One of the middle plates is polarized throughout its thickness; the other two middle plates contain segments polarized along their thickness in opposite directions. Sections with segmented plates are rotated relative to each other by 90° around the longitudinal axis of the package. The technical result is an expansion of functionality by measuring vibration acceleration in three mutually perpendicular directions.
The vibration sensor according to patent No. 2331076 contains a piezoceramic tubular rod with electrodes, fixed in the housing at one end on a base with electrical contacts perpendicular to its surface, and at the other end of the rod an inertial element is fixed, made in the form of a mass-structure, which consists of a thin-walled cylinder, the cavity of which filled with a fluid damping medium (for example, low-viscosity oil) and individual spherical weights, with the possibility of their free movement, while the spherical weights have different masses. Inside the housing there is a damping element, which is also used as a fluid damping medium. The technical result is to expand the measurement range while increasing the sensitivity of the sensor.
The vibration transducer according to patent No. 2347228 contains a housing with a piezoelectric element fixed in it, made in the form rectangular parallelepiped with a square base and with charge removal elements in the form of electrically conductive surfaces fixed on its edges and electrically isolated from each other, conductors for charge removal and a dielectric substrate on which a square base of a piezoelectric element is mounted, the polar axis of which is perpendicular to the plane of its attachment to the substrate. Each electrically conductive surface is made in the form of a plate with a petal protruding on one of its sides beyond the corresponding face of the parallelepiped, made of isotropic copper foil and fixed to the edge of the parallelepiped by means of a polymerizable thermosetting conductive material, while on each pair of adjacent plates the petals are oriented to different edges of the parallelepiped , each petal has a notch for attaching a conductor to remove charges, and the axis of each petal coincides with one of the symmetry planes of the corresponding plate. This design of the converter makes it possible to move the attachment points of conductors to the charge removal elements, as the most pronounced stress concentrators, beyond the charge removal surfaces of the sensitive element and makes it possible to implement technologies for manufacturing parts and installing a piezoelectric bag in an industrial manner, which minimizes inhomogeneity and mechanical stresses on the edges of the piezoelectric element.
The three-component oscillatory acceleration sensor according to patent No. 2383025 contains a housing that is rigidly fixed to the base base and closed with a cap. The body is made of metal in the shape of a triangular pyramid with three orthogonal planes, on each of which one sensitive element is fixed in a cantilever manner. Sensing elements are made in the form of piezoelectric or bimorph plates.
The device for measuring vibration according to patent No. 2382368 contains a piezoelectric transducer, an instrumentation amplifier and an operational amplifier, the output of which is the output of the device. The outputs of the piezoelectric transducer are connected to the direct and inverse inputs of the instrumentation amplifier, the first gain input of which is connected to the first terminal of the first resistor. The output of the operational amplifier is connected to its inverse input through a capacitor. The inverse input of the operational amplifier is connected through a second resistor to the output of the instrumentation amplifier. The direct input of the operational amplifier is connected to the common bus. An inductance is introduced into the device, which is connected between the second output of the first resistor and the second input of the instrumentation amplifier gain setting, and a third resistor is connected in parallel with the capacitor. The direct and inverse inputs of the instrumentation amplifier can be connected to the common bus through the first and second auxiliary resistors.
The essence of the piezoelectric measuring transducer according to patent No. 2400867 is that it contains a piezoelectric transducer and a preamplifier. The first part of the preamplifier is located in the transducer housing and includes an amplification stage based on a field-effect transistor and three resistors. The second part of the preamplifier is located outside the housing and includes a coupling capacitor and a current-stabilizing diode, the cathode of which and the first terminal of the coupling capacitor are connected to the source of the field-effect transistor. The second terminal of the separating capacitor and the anode of the current-stabilizing diode are connected, respectively, to the recorder and the power source, the common point of which is connected to the drain of the field-effect transistor. The converter also contains first and second diodes connected in series. The cathode of the first and the anode of the second diodes are connected, respectively, to the source and drain of the field-effect transistor. Their middle point is connected to the gate of the field-effect transistor, to the first electrode of the piezoelectric transducer, to the first terminal of the first resistor, the second terminal of which is connected to the first terminals of the second and third resistors. The second terminal of the second resistor is connected to the source of the field-effect transistor. The second terminal of the third resistor is connected to the second electrode of the piezoelectric transducer and to the drain of the field-effect transistor. Technical result: simplification of the electrical circuit, reduction of the self-noise level and protection against breakdown of the field-effect transistor.
Patent studies have shown that today there are quite a large number of piezoelectric vibration measuring instruments, varied in their design and having both advantages and disadvantages.
Thus, the use of sensors that allow vibration to be determined based on the properties of piezoelectric crystals is quite relevant.
3 Automation of LPDS “Cherkassy”
3.1 Automation of the main pumping unit
Automation of a pumping station includes control of main pumping units in start-stop modes, automatic control, protection and alarm of pumping units and the station as a whole according to controlled parameters, automatic start-stop, control, protection and alarm of auxiliary installations of pumping stations.
The control system for pumping units operates in the modes of remote operational control, program start of pumps, program stop of pumps and emergency stop.
In remote control modes, the control room panel starts the oil pump, controls the ventilation of the pump room, and controls the opening and closing of valves on the suction and discharge lines of main pumping units.
In the programmatic start and stop mode of the MNA, all startup operations are performed automatically. The starting mode of an electric motor depends on its type (synchronous or asynchronous) and is carried out by starting stations.
In general, starting a main pumping unit is quite simple. When the electric motor reaches the nominal speed, the suction and discharge valves open and the unit starts working. The oil supply system at a modern pumping station is centralized, common to all units, which eliminates the control of oil system pumps and seals when starting and stopping the unit.
For pumping LPDS, the program launch of the MNA is important. There are various pump starting schemes available depending on the characteristics of the pumps, electrical circuits and other factors. The programs for sequentially opening the valves and starting the main electric motor of the unit differ.
Units transferred to the reserve position for the ATS system can also be switched on according to a program in which both valves open in advance when the unit is switched to reserve, and the main electric motor starts when the operating unit is turned off and the ATS system is activated. This program for turning on the unit is the best from the point of view of the hydraulic operating conditions of the main pipeline, since with such switching of units, the pressure at the suction and discharge of the station changes very slightly and linear part the main pipeline experiences practically no loads due to pressure waves.
The unit shutdown program, as a rule, involves simultaneously turning off the main electric motor and turning on both valves to close. In this case, the command to close the valves is usually given by a short pulse (Figure 3.1).
Protection of the pumping unit in terms of the parameters of the pumped liquid is provided by pressure sensors 1-1, 1-2, 7-1, 7-2 (Sapphire-22MT), which monitor pressure in the suction and discharge pipelines. Sensors 1-1, 1-2 installed on the suction pipeline at the inlet valve are adjusted to the pressure characterizing the cavitation mode of the pump. Protection by minimum pressure suction is carried out with a time delay, which eliminates the reaction to short-term drops in pressure when turning on pumps and passing through the pipeline small air jams. Sensors 7-1, 7-2 installed on the discharge pipeline near the outlet valves provide protection for maximum discharge pressure. The maximum contact of sensor 7-1 gives a signal to the unit control circuit, interrupting the startup process if the permissible pressure is exceeded after opening the valve. The maximum contact of the sensor 7-1 ensures automatic shutdown of the unit if a signal is sent to the unit control circuit, interrupting the start-up process if the permissible pressure is exceeded after opening
startup process in case of exceeding the permissible pressure after opening the valve.
The maximum contact of sensor 7-1 ensures automatic shutdown of the unit if the pressure in the discharge pipeline exceeds what is permissible under the conditions of the mechanical strength of the equipment, fittings and pipeline.
In operation, there may be cases where the pump operates with a very low flow, which is accompanied by a rapid increase in the temperature of the liquid in the pump housing, which is unacceptable.
Protection against an increase in oil temperature in the pump casing is provided by a resistance thermal converter 9 installed on the pump casing. Violation of the tightness of the pump shaft sealing devices requires immediate shutdown of the unit. Leak control comes down to monitoring the level in the chamber through which leaks are discharged. Excess permissible level fixed by level gauge 3-1.
Protection against excess temperature of bearings 2-1, 2-2, 2-3, 2-4 is carried out by a resistance thermal converter of the TSMT type. An alarm is triggered in the control room, and the unit is switched off by protection using a control signal from the controller.
Protection against temperature rise of the stator core windings is carried out by resistance thermometer 10 TES-P.-1. The air temperature in the electric motor housing is monitored and signaled by means of a control signal from the controller.
The pressure in the sealing fluid and circulating lubrication systems of pump and electric motor bearings is controlled by a Sapphire-22MT pressure sensor and controller.
Vibration alarm equipment 4-1, 4-2, 4-3, 4-4 monitors the vibration of the bearings of the pump and electric motor, and if it increases to unacceptable values, it turns off the unit.
Table 3.1 List of selected MNA equipment
|
Positional designation |
Name |
Note |
|
|
Pressure sensor type Sapphire-22MT |
|||
|
Pressure gauge indicating ECM type |
|||
|
Resistance thermal converter platinum type TSP100 |
|||
|
Level switch type OMYUV 05-1 |
|||
|
Vibration monitoring equipment "Cascade" |
Emergency stop unit occurs when instruments and protection devices are triggered. There are emergency stops that allow restarting of the unit and those that do not allow it. In the latter case, the reason that caused the stop is established and eliminated, and only after that it becomes possible to restart the unit. A stop with permission to restart occurs when the start fails, that is, if the stop occurred due to the temperature of the product in the pump casing. An emergency stop with prohibition of restarting the unit occurs under the following parameters: an increase in the temperature of the bearings of the electric motor, pump and intermediate shaft; increased vibration of the unit; increased leakage from pump shaft seals; an increase in the temperature of the cooling air at the inlet to the electric motor; increasing the temperature difference between the incoming and outgoing air cooling the electric motor; activation of electrical motor protection devices.
Sequence of operations when stopping units by signals protective automation does not differ from the sequence for a normal program stop.
In general, the pumping station also has a warning alarm and emergency protection system the following parameters: fire, flooding of the pumping station, unacceptable pressure on the suction and discharge lines, etc.
Automatic stopping of the station units occurs sequentially according to the program, with the exception of the case of gas protection. If there is an increased concentration of oil vapor in the pump room, all electricity consumers, except fans and control devices, are simultaneously switched off. The automation scheme of the pumping station provides fire protection (sensors are installed that respond to the appearance of smoke, flame or elevated temperature in the room); when they are triggered, all electricity consumers are switched off without exception.
The list of devices used to automate the main pumping unit is given in Table 3.2.
Table 3.2 Devices used for MNA automation
|
script |
Position designation |
Trigger condition |
Action |
|
Exceeding the temperature of the front pump bearings |
Decrease in ED speed |
||
|
Exceeding the temperature of the rear pump bearings |
Decrease in ED speed |
||
|
Exceeding the temperature of the oil product in the pump housing |
Decrease in ED speed |
||
|
Exceeding the temperature of the front ED bearings |
Decrease in ED speed |
||
|
Temperature rise of stator core windings |
Decrease in ED speed |
||
|
Exceeding the temperature of the rear ED bearings |
Decrease in ED speed |
||
|
Excessive vibration of front ED bearings |
Decrease in ED speed |
||
|
excessive vibration of rear ED bearings |
Decrease in ED speed |
||
|
excessive vibration of the rear pump bearings |
Decrease in ED speed |
||
|
Excessive vibration of the pump front bearings |
Decrease in ED speed |
3.2 Emergency protection system
The reliability of the functioning of safety systems for hazardous industrial facilities depends entirely on the state of electronic and programmable electronic systems related to safety. These systems are called emergency protection systems (EPS). Such systems must be able to maintain their functionality even in the event of failure of other functions of the process control system of the oil pumping station.
Let's consider the main tasks assigned to such systems:
Preventing accidents and minimizing the consequences of accidents;
Blocking (preventing) intentional or unintentional interference in the technology of an object that could lead to the development dangerous situation and initiate the ESD operation.
Some protections require a delay between alarm detection and tripping. Disabling the main auxiliary systems, closing the valves connecting the pumping station to the oil pipeline.
The pumping unit is continuously monitored for a number of technological parameters, the emergency values of which require shutting down and blocking the operation of the unit. Depending on the parameter or condition by which the protection was triggered, the following can be performed:
Switching off the electric motor;
Closing the unit valves;
Starting the backup unit.
A test mode is provided for all protection parameters. In test mode, a protection flag is set, an entry in the protection array is set, and a message is transmitted to the operator, but control actions on technological equipment are not formed.
Depending on which controlled parameter triggers the plant-wide protection associated with shutting down the pumping units, the system must:
Shutdown of one of the operating MPUs, the first one along the oil flow;
Simultaneous or sequential shutdown of all working MNAs;
Simultaneous shutdown of all operating PNAs;
Closing the pump connection valves;
Closing the FGU valves;
Disabling certain auxiliary systems;
Turning on light and sound signaling devices.
The aggregate protections of the MPU and PPU must ensure its trouble-free operation and shutdown when the controlled parameters go beyond the established limits.
The algorithmic content of the ESD functions consists in the implementation of the following condition: when the values of certain technological parameters characterizing the state of the process or equipment exceed the established (permissible) limits, the corresponding unit or the entire station must be switched off (shutdown).
The input information for the group of emergency protection functions contains signals about the current values of controlled technological parameters, arriving at logical blocks (programmable controllers) from the corresponding primary measuring transducers, and digital data about the permissible limit values of these parameters, arriving at the controllers from the remote control station operator's workstation. The output information of the emergency protection functions is represented by a set of control signals sent by the controllers to the executive bodies of the protection systems.
Availability feedback significantly simplifies the process of developing target processor tasks and user applications. On the other hand, this increases the invariance of the reaction of logical and computational algorithms to the test impact carried out when checking emergency protection.
Such a check cannot guarantee the repeatability of test results, since the state of the processor memory under feedback control under all the same testing conditions will not be the same at different points in time.
3.3 Process control system based on Modicon TSX Quantum controllers
The automated process control system (APCS) of oil pumping stations is based on the Modicon TSX Quantum series of programmable controllers, which is a good solution for control tasks based on high-performance programmable controllers. The Quantum-based system is compact, providing cost-effective and reliable installation even in the most challenging applications. industrial conditions. At the same time, Quantum systems are easy to install and configure, have a wide range of applications, which ensures a lower cost compared to other solutions. It also provides support for installed products by combining legacy technologies with this latest management platform. The design of Modicon TSX Quantum programmable controllers allows you to save space in the panel. With a depth of only 4 inches (including screen), these controllers do not require large shields; they fit in a standard 6-inch electrical cabinet, which allows you to save up to 50% of the cost of conventional control panels. Despite their small size, Quantum controllers maintain high levels of performance and reliability. Control systems using Modicon TSX Quantum series programmable controllers support various options solutions ranging from a single I/O rack (up to 448 I/O) to redundant processors with extensive I/O with up to 64,000 I/O lanes, configurable to meet your needs. In addition, memory capacity from 256 KB to 2 MB is sufficient for the most complex control schemes. Thanks to the use of advanced processor devices based on Intel chips, the performance of the Quantum series controllers and throughput I/O is sufficient to meet stringent speed requirements. These controllers also use high-performance math coprocessors to provide the best algorithm execution speed and math calculations needed to ensure process continuity and quality.
The combination of performance, flexibility and expandability makes the Quantum series the best solution for the most complex applications while being cost-effective enough for simpler automation tasks. The ability to connect to enterprise networks and field buses is implemented for eight types of networks from Ethernet to INTERBUS-S.
Quantum supports five programming languages that comply with the IEC 1131-3 standard. In addition to these languages, Quantum controllers can run programs written in Modicon 984 ladder language, Modicon state language and application-specific languages developed by other companies.
In addition to IEC languages, the Quantum system takes advantage of the enhanced 984 instruction set to run application programs written in Modsoft or translated from SY/Mate on the Quantum controller. It is possible to connect Ethernet, Modbus and Modbus Plus backbone communication networks to the Quantum controller.
No system architecture meets the needs of today's control market better than the Modicon TSX Quantum series of programmable controllers. It provides an alternative system in which I/O nodes are sized, spatially distributed, and configured to reduce the cost of cabling connecting I/O nodes to sensors and actuators. The Quantum controller has the flexibility to combine local, remote, distributed I/O, peer-to-peer, and field I/O bus configurations. This flexibility makes Quantum a unique solution to meet all automation needs. Using just one series of I/O modules, the Quantum system can be configured for all architectures and is therefore suitable for process control, machine control or distributed control.
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This guidance document applies to centrifugal feed pumps with a power of more than 10 mW driven by a steam turbine and an operating speed of 50 - 150 s -1 and establishes vibration standards for bearing supports of centrifugal feed pumps that are in operation and put into operation after installation or repair, and also general requirements for measurements.
This guidance document does not apply to turbine drive supports for pumps.
1 . VIBRATION STANDARDS
1.1. The following parameters are set as normalized vibration parameters:
double amplitude of vibration movements in the frequency range from 10 to 300 Hz;
root mean square value of vibration velocity in the operating frequency band from 10 to 1000 Hz.
1.2. Vibration is measured on all pump bearings in three mutually perpendicular directions: vertical, horizontal transverse and horizontal axial with respect to the axis of the feed pump shaft.
1.3. The vibration state of feed pumps is assessed by the highest value of any measured vibration parameter in any direction.
1.4. Upon acceptance after installation of feed pumps, vibration of the bearings should not exceed the following parameters:
1.6. If the vibration standards established in paragraphs are exceeded. 1.4 and 1.5, measures must be taken to reduce it within no more than 30 days.
1.7. It is not allowed to operate feed pumps at vibration levels above:
according to the level of vibration movements - 80 microns;
in terms of vibration velocity - 18 mm/s;
upon reaching the specified level for any of these two parameters.
1.8. Vibration standards for bearing supports must be recorded in the operating instructions for feed pumps.
2 . GENERAL REQUIREMENTS FOR MEASUREMENTS
2.1. Measurements of vibration parameters of centrifugal feed pumps are carried out at steady state.
2.2. The vibration of feed pumps is measured and recorded using stationary equipment for continuous monitoring of vibration of bearing supports, meeting the requirements of GOST 27164-86.
2.3. The equipment must provide measurement of the double amplitude of vibration displacements in the frequency range from 10 to 300 Hz and the root mean square value of vibration velocity in the frequency range from 10 to 1000 Hz.
The equipment used must have a measurement limit of 0 to 200 µm for vibration displacements and from 0 to 31.5 mm/s for vibration velocities.
2.4. Sensors for measuring the horizontal transverse and horizontal axial vibration components are attached to the bearing cover. The vertical component of vibration is measured at the top of the bearing cover above the middle of the length of its shell.
2.5. The transverse sensitivity coefficient of the sensor should not exceed 0.05 over the entire frequency band in which measurements are taken.
2.6. Installed sensors must be protected from steam, turbine oil, OMTI liquid and operate normally at ambient temperatures up to 100 °C, humidity up to 98% and magnetic field strength up to 400 A/m.
2.7. The operating conditions of measuring amplifiers and other equipment units must comply with GOST 15150-69 for version 0 category 4.
2.8. The maximum basic reduced error in measuring the double amplitude of vibration displacement should not exceed 5%. The main error in measuring the root mean square value of vibration velocity is 10%.
2.9. Before installing stationary equipment for continuous vibration monitoring of feed pumps in operation, it is allowed to measure vibration with portable instruments that meet the stated requirements.
3 . REGISTRATION OF MEASUREMENT RESULTS
3.1. The results of vibration measurements when accepting the feed pump into operation are documented in an acceptance certificate, in which they must be indicated.
The vibration of pumping units is mainly low- and medium-frequency of hydro-aerodynamic origin. The level of vibration, according to a survey of some pump stations, exceeds sanitary standards by 1-5.9 times (Table 29).
When vibration propagates through the structural elements of units, when the natural frequencies of vibration individual parts turn out to be close and equal to the frequencies of the main current or its harmonics, resonant oscillations arise and threaten the integrity of some components and parts, in particular the angular contact rolling bearing and the oil lines of the journal bearings. One of the means of reducing vibration is to increase losses due to inelastic resistance, i.e., applying to the pump and electric motor housing
Unit brand
24ND-14X1 NM7000-210
| 1,9-3,1 1,8-5,9 1,6-2,7 |
ATD-2500/AZP-2000
AZP-2500/6000
Note. Rotation speed 3000 rpm.
Ziber-absorbing coating, for example ShVIM-18 mastic. The source of low-frequency mechanical vibration of units on the foundation is the force of imbalance and the amount of misalignment of the pump and motor shafts, the frequency of which is a multiple of the shaft rotation speed divided by 60. Vibration caused by shaft misalignment leads to increased loads on the shafts and plain bearings, their heating and destruction, loosening of machines on the foundation, cutting anchor bolts, and in some cases - to a violation of the explosion permeability of the electric motor. At pump stations, to reduce the amplitudes of shaft vibration and increase the standard overhaul period of Babbitt plain bearings to 7000 motor-hours, calibrated steel spacer sheets are used, installed in the connectors of the bearing caps to select the wear gap.
Reducing mechanical vibration is achieved by careful balancing and alignment of shafts, timely replacement of worn parts and elimination of maximum clearances in bearings.
The cooling system must ensure that the bearing temperature does not exceed 60 °C. If the oil seal becomes excessively hot, the pump should be stopped and started immediately several times to allow oil to seep through the packing. The absence of oil indicates that the oil seal is packed too tightly and should be loosened. When knocking occurs, the pump is stopped to determine the cause of this phenomenon: the lubricant and oil filters are checked. If the pressure loss in the system exceeds 0.1 MPa, the filter is cleaned.
Heating of the bearings, loss of lubricant flow, excessive vibration or abnormal noise indicate problems with the pump unit. It must be stopped immediately to resolve any detected problems. To stop one of the pumping units, close the valve on the discharge line and the valve on the hydraulic discharge line, then turn on the engine. After cooling the pump, close all the valves of the pipelines supplying oil and water, and the taps at the pressure gauges. When stopping the pump for a long time to prevent corrosion, the impeller, sealing rings, shaft protectors, bushings and all parts in contact with the pumped liquid should be lubricated and the stuffing box should be removed.
During the operation of pumping units, various problems are possible, which can be caused by various reasons. Let's look at pump malfunctions and ways to eliminate them.
1. The pump cannot be started:
the pump shaft connected by a gear coupling to the electric motor shaft does not rotate - check manually the rotation of the pump and electric motor separately, the correct assembly of the gear coupling; if the shafts rotate separately, ta.216
check the alignment of the unit; check the operation of the pump and wire when they are connected through a turbo transmission or gearbox;
the pump shaft, disconnected from the electric motor shaft, does not rotate or rotates slowly due to foreign objects getting into the pump, breakage of its moving parts and seals, jamming in the sealing rings - carry out an inspection, sequentially eliminating the detected mechanical damage.
2. The pump is started, but does not supply liquid or after starting
its supply stops:
the suction capacity of the pump is insufficient, since there is air in the suction pipe due to incomplete filling of the pump with liquid or due to leaks in the suction pipe, seals - repeat filling, eliminate the leak;
incorrect rotation of the pump shaft - ensure correct rotation of the rotor;
the actual suction height is greater than the permissible one, due to the discrepancy between the viscosity, temperature or partial vapor pressure of the pumped liquid and the design parameters of the installation - to ensure the necessary backwater.
3. The pump consumes more power when starting: ■
the valve on the pressure pipeline is open - close
valve during start-up;
Impellers are installed incorrectly - correct incorrect assembly;
Seizing occurs in the sealing rings due to large gaps in the bearings or as a result of rotor displacement - check the rotation of the rotor by hand; if the rotor rotates slowly, remove the jamming;
the tube of the loading device is clogged - inspect and: clean the pipeline of the unloading device;
A fuse blows in one of the motor phases - replace the fuse.
4. The pump does not create the design pressure:
the pump shaft rotation speed is reduced - change the rotation speed, check the engine and eliminate faults;
the sealing rings of the impeller and the leading edges of the rotor blades are damaged or worn - replace the impeller and damaged parts;
the hydraulic resistance of the discharge pipeline is less than the calculated one due to a rupture of the pipeline, excessive opening of the valve on the discharge or bypass line - check the supply; if it has increased, then close the valve on the bypass line or cover it on the discharge line; eliminate various types of leaks in the discharge pipeline;
The density of the pumped liquid is less than the calculated one, the content of air or gases in the liquid is increased - check the density of the liquid and the tightness of the suction pipeline and seals;
cavitation is observed in the suction pipeline or working parts of the pump - check the actual cavitation reserve of specific energy; if its value is too low, it eliminates the possibility of the appearance of a cavitation regime.
5. Pump flow is less than calculated:
rotation speed is less than nominal - change the rotation speed, check the engine and eliminate faults;
the suction height is greater than permissible, as a result of which the pump operates in cavitation mode - perform the work specified in paragraph 2;
the formation of funnels on the suction pipeline, which is not deeply immersed in the liquid, as a result of which air enters with the liquid - install a cut-off device to eliminate the funnel, increase the liquid level above the inlet of the suction pipeline;
an increase in resistance in the pressure pipeline, as a result of which the pump discharge pressure exceeds the design pressure - fully open the valve on the discharge line, check all valves of the manifold system, line valves, and clean any clogged areas;
the impeller is damaged or clogged; the gaps in the sealing rings of the labyrinth seal are increased due to their wear - clean the impeller, replace worn and damaged parts;
air penetrates through leaks in the suction pipeline or oil seal - check the tightness of the pipeline, stretch or replace the oil seal packing.
6. Increased power consumption:
pump flow is higher than calculated, the pressure is less due to the opening of the valve on the bypass line, a rupture of the pipeline or excessive opening of the valve on the discharge pipeline - close the valve on the bypass line, check for leaks pipeline system or close the valve on the pressure pipeline;
the pump is damaged (impellers, o-rings, labyrinth seals are worn out) or the motor - check the pump and motor and repair the damage.
7. Increased vibration and pump noise:
bearings are displaced due to loosening of their fastening; bearings are worn out - check the shaft alignment and bearing clearances; in case of deviation, bring the size of the gaps to the permissible value;
the fastenings of the suction and discharge pipelines, foundation bolts and valves are loose - check the fastening of the components and eliminate any deficiencies; 218
foreign objects entering the flow part - clean the flow part;
the balance of the pump or motor is disturbed due to bending of the shafts, incorrect alignment or eccentric installation of the coupling - check the alignment of the shafts and coupling, eliminate the damage;
increased wear and play in check valves and gate valves on the discharge pipeline - eliminate the play;
the rotor is not balanced as a result of the impeller being clogged - clean the impeller and balance the rotor;
the pump operates in cavitation mode - reduce the flow by closing the valve on the discharge line, seal the connections in the suction pipeline, increase the pressure, reduce the resistance in the suction pipeline.
8. Increased temperature of oil seals and bearings:
heating of the oil seals due to excessive and uneven tightening, small radial clearance between the pressure sleeve and the shaft, installation of the sleeve with a skew, jamming or distortion of the oil seal lantern, insufficient supply of sealing fluid - loosen the tightening of the oil seals; if this does not give effect, then disassemble and eliminate installation defects, replace the packing; increase the supply of sealing fluid;
heating of bearings due to poor oil circulation in forced system bearing lubrication, lack of rotation of rings in bearings with ring lubrication, oil leakage and contamination - check the pressure in the lubrication system, the operation of the oil pump and eliminate the defect; ensure the tightness of the oil bath and pipeline, change the oil;
heating of the bearings due to improper installation (small gaps between the liner and the shaft), wear of the liners, increased tightening of the support rings, small gaps between the washer and rings in the thrust bearings, scuffing of the support or thrust bearing or melting of the babbitt - check and eliminate defects; clean the burrs or replace the bearing.
Piston compressors. Parts where the most dangerous defects may occur include shafts, connecting rods, crossheads, rods, cylinder heads, crank pins, bolts and studs. The zones in which the maximum stress concentration is observed are threads, fillets, mating surfaces, press-fittings, journals and cheeks of columnar shafts, and keyways.
When operating the frame (bed) and guides, check the deformation of their elements. Vertical movements exceeding 0.2 mm are a sign of compressor inoperability. Cracks are identified on the surface of the frame and their development is monitored.
The contact between the frame and any of the guides fixed to the foundation must be at least 0% of the perimeter of their common joint. At least once a year, check the horizontal position of the frame (the deviation of the frame plane in any direction over a length of 1 m should not exceed 2 mm). The sliding surfaces of the guides should not have marks, dents, or nicks more than 0.3 mm deep. For the crankshaft during operation, the temperature of its sections operating in friction mode is monitored. It should not exceed the values specified in the operating instructions.
For connecting rod bolts, check their tightening, the condition of the locking device and the surface of the bolt. Signs of bolt inoperability are as follows: cracks on the surface, in the body or thread of the bolt, corrosion in the fit part of the bolt, breakage or collapse of thread turns. The total contact area must be at least 50 °/about the area of the support belt. Contact spots should not be have breaks exceeding 25% of the circumference. If the residual elongation of the bolt exceeds 0.2% of its original length, the bolt is rejected.
For the crosshead, the condition of the elements of its connection with the rod, as well as the pin, is checked, and the gaps between the upper guide and the crosshead shoe are checked. During operation, pay attention to the condition of the outer surface of the cylinder, the seal of the oil lines of the indicator plugs, and the flange connections of the water cooling system. Fistulas and leaks of gas, water, oil in the housing or flange connections are unacceptable. The water temperature at the outlet of the water jackets and cylinder covers should not exceed the values given in the operating instructions.
For pistons, the surface condition is subject to control (including the condition and thickness of the bearing surface of the sliding type piston), as well as the fixation of the piston on the rod and plugs (for cast pistons) of the pressure stage. Signs of piston rejection are the following: scoring in the form of grooves on an area of more than 10% of the casting surface, the presence of areas with lagging, melted or crumbled babbitt, as well as cracks with a closed contour. The radial crack of the fill layer should not decrease to 60% of the original one. Violation of the fixation of the piston nut for the plugs of cast pistons, play of the piston on the rod, looseness of the surface of the welds, and separation of the piston bottom from the stiffeners are not allowed.
For rods, before taking the compressor out for repair, the rod runout within the stage piston and the condition of the rod surface are monitored; detect scoring or traces of metal envelopment of the sealing elements on the surface of the rod. No cracks on the surface, threads or 220 are allowed
rod fillets, deformation, thread failure or collapse. During operation, check the tightness of the rod seal, not equipped with and equipped with a leakage drainage system. The indicator of the tightness of rod seals is the gas content in the controlled areas of the compressor and the room, which should not exceed the values allowed by current standards.
During repairs, the condition of the rod seal is checked annually. Cracks on the element or its breakage are unacceptable. Wear of the sealing element should be no more than 30% of its nominal radial thickness, and the gap between the rod and the protective ring of the rod seal with non-metallic sealing elements should be no more than 0.1 mm.
During operation, the performance of the piston rings is monitored using regulated pressures and temperatures of the compressed medium. There should be no increase in cylinder noise or knocking noise. The scoring of the sliding surface of the rings should be less than 10% of the circumference. If the radial wear of the ring in any section exceeds 30% of the original thickness, the ring is rejected.
Signs of valve inoperability are as follows: abnormal knocking in the valve chambers, deviations of pressure and temperature of the compressed medium from the regulated ones. When monitoring the condition of valves, check the integrity of the plates, springs and the presence of cracks in the valve elements. The flow area of the valve as a result of contamination should not decrease by more than 30% of the original, and the density should not be lower than the established standards.
Piston pumps. Cylinders and their liners may have the following defects: wear work surface as a result of friction, corrosive and erosive wear, cracks, scuffing. The amount of cylinder wear is determined after removing the piston (plunger) by measuring the diameter of the bore in the vertical and horizontal planes along three sections (the middle and two extreme ones) using a micrometer gauge.
Scuffs, nicks, burrs and torn edges are not allowed on the working surface of the piston. The maximum permissible piston wear is (0.008-0.011) Г> p, where About l- minimum piston diameter. If cracks are detected on the surface of the piston rings, significant and uneven wear, ellipse, or loss of elasticity of the rings, they must be replaced with new ones.
The rejection gaps of the pump piston rings are determined as follows: the smallest gap in the ring lock in the free state D" (0.06^-0.08) B; the largest gap in the ring lock in working condition is L = k (0.015-^0.03) D where ABOUT- minimum cylinder diameter.
The permissible radial warpage for rings with a diameter of up to 150, 150-400, over 400 mm is, respectively, no more than 0.06-0.07; 0.08-0.09; 0.1-0.11 mm.
The rejection gap between the rings and the walls of the piston grooves is calculated according to the following ratios: L t = = 0.003 /g; A t ax = (0.008-4-9.01) To, Where To- nominal height of the rings.
If scratches with a depth of 0.5 mm and an ellipse of 0.15-0.2 mm are detected, the rods and plungers are ground. The rod can be ground to a depth of no more than 2 mm.
Misalignment of the cylinder and the rod guide is acceptable within 0.01 mm. If the runout of the rod exceeds 0.1 mm, then the rod is ground to 7 g of the runout value or straightened.
Technological processes in the Kaltasy LPDS pumping station are accompanied by significant noise and vibration. Sources of intense noise and vibration include booster (20NDsN) and main (NM 2500-230, NM1250-260) pumps, elements of ventilation systems, pipelines for moving oil, electric motors (VAO - 630m, 2AZMV1 2000/6000) and other process equipment.
Noise affects the hearing organs, leading to partial or complete deafness, i.e. to occupational hearing loss. This disrupts the normal functioning of the nervous, cardiovascular and digestive systems, resulting in chronic diseases. Noise increases human energy costs, causes fatigue, which reduces the production activity of labor and increases defects in work.
Prolonged exposure to vibration on a person causes occupational vibration disease. The impact of vibration on biological tissue and the nervous system leads to muscle atrophy, loss of elasticity of blood vessels, ossification of tendons, disruption of the vestibular apparatus, decreased hearing acuity, deterioration of vision, which leads to a decrease in labor productivity by 10-15% and is partly the cause of injuries. Noise standards in workplaces, general requirements for the noise characteristics of units, mechanisms and other equipment are established in accordance with GOST 12.1.003-83.
Table 4. - Valid values sound pressure level in the pump shop and vibration of the pump unit
|
Measurement location |
Sound level, dB |
Acceptable by standard, dB |
Maximum speed, mm/s |
Emergency maximum, mm/s |
|
Pumping station |
||||
|
Bearing vibration:
|
||||
|
Body vibration:
|
||||
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Foundation vibration |
Protection from noise and vibration is provided by SN-2.2.4./2.1.8.566-96, let’s consider the most typical measures for a pumping shop:
- 1. remote control equipment;
- 2. sealing windows, openings, doors;
- 3. elimination of technical deficiencies and equipment malfunctions that are a source of noise;
- 4. timely preventive maintenance according to the schedule, replacement of worn parts, regular lubrication of rubbing parts.
As individual funds Headphones or antiphons are used to protect against noise.
To reduce or eliminate vibration, SN-2.2.4./2.1.8.566-96 provides the following measures:
- 1. correct design of foundations for equipment, taking into account dynamic loads and insulating them from load-bearing structures and engineering communications;
- 2. alignment and balancing of rotating parts of units.
Workers exposed to vibration should undergo regular medical examinations.
