Ball valves, coupling, flange, welded: types of connection. Methods for connecting fittings to a pipeline Ball valves by type of connection
IN apartment buildings Residents mainly use the central heating network to heat their premises. The quality of these services is influenced by many factors: the age of the house, wear and tear of equipment, the condition of the heating main, etc. A special scheme for connecting to the heating network is also of significant importance in the heating system.
Connection types
Connection schemes can be of two types: dependent and independent. Connecting using the dependent method is the simplest and most common option. Independent system heating has gained popularity in lately, and is widely used in the construction of new residential areas. Which solution is more effective for providing warmth, comfort and coziness to any room?
Dependent
This connection scheme, as a rule, provides for the presence of in-house heating points, often equipped with elevators. IN mixing unit At the heating station, superheated water from the main external network is mixed with the return water, thereby acquiring a sufficient temperature (about 100°C). Thus, the internal heating system of the house is completely dependent on external heat supply.
Advantages
The main feature of this scheme is that it provides for the supply of water to the heating and water supply systems directly from the heating main, and the price pays off quite quickly.
Flaws
Along with the advantages, such a connection also has some disadvantages:
- uneconomical;
- adjustment temperature regime significantly difficult during weather changes;
- overconsumption of energy resources.
Connection methods
Connection can be made in several ways:
Independent
An independent heat supply system allows you to save consumed resources by 10-40%.
Operating principle
The consumer heating system is connected using an additional heat exchanger. Thus, heating is carried out by two hydraulically isolated circuits. The external heating circuit heats the water of the closed internal heating network. In this case, water mixing does not occur, as in the dependent version.
However, such a connection requires considerable costs for both maintenance and repair work.
Water circulation
The movement of the coolant is carried out in the heating mechanism thanks to circulation pumps, due to which there is a regular supply of water through heating devices. An independent connection circuit may have an expansion vessel containing a supply of water in case of leaks.
Components of an independent system.
Scope of application
Widely used to connect to heating system multi-storey buildings or buildings that require an increased level of reliability of the heating mechanism.
For facilities that have premises where access to outside service personnel is undesirable. Provided that the pressure in the return heating systems or heating networks above the permissible level - more than 0.6 MPa.
Advantages
Negative points
- high cost;
- difficulty of maintenance and repair.
Comparison of the two types
The quality of heat supply according to a dependent scheme is significantly affected by the operation of the central heat source. This is a simple, cheap method that does not require special maintenance or repair costs. However, the advantages of a modern independent connection scheme, despite the financial costs and complexity of operation, are obvious.
2018-01-16T15:39:03+03:00
One of the main questions when choosing pipeline fittings is the type of its connection to the system. Usually the existing pipeline system itself dictates to us which type of connection to choose. But if you are faced with the task of designing such a system, then it is important to know everything possible types connecting pipeline fittings to the system to select the ideal option for your conditions. From our article you will learn about all types, their pros and cons, and you will better understand the types of connections. We'll start with the most popular ones.
Flange connection
This is a connection using two metal plates adjacent to each other. The plates have holes through which bolts or studs pass and are tightened with nuts on the other side, thus pressing the flanges together. For greater reliability and tightness of the connection, protrusions, grooves, etc. are made on the plates, and gaskets are installed between the metal plates. Most often the plates have a rounded shape, but this is not necessary. Occasionally you can find square flanges, rectangular or with three corners, but their production is more expensive. Such forms of flanges are used only when strictly necessary, for example, if space limitations require it. Used on industrial pipelines diameter from DN 50 mm.
The word “flange” comes from the German flansch, which means the same thing as in Russian – a flat metal plate with holes.
Flange connection is one of the most popular connections in pipeline fittings. For the manufacture of flanges, cast iron is most often used - gray or malleable, as well as steel different varieties. Gray cast iron is the most inexpensive solution, but ductile iron can generally withstand a greater range of pressures and temperatures. An even more expensive and durable solution is cast steel flanges. But at the same time, steel is more susceptible to plastic deformation than cast iron, which is brittle but holds its shape well.
Video: installing a flanged LD ball valve on a pipe using
Advantages of flange connection of pipeline fittings
- Strong, reliable connection.
- Withstands high pressure.
- High tightness. But it depends on the seals used.
- Can be mounted and dismantled many times.
Flaws
- Large overall dimensions flange connection. Large mass.
- High metal consumption and labor-intensive production, and therefore the price.
- The bolts holding the flanges together must be tightened periodically to ensure proper tightness. This is especially important in systems where the pipe is subject to vibration (solved by installation in front of the flange connection) or temperature changes.
Threaded, coupling connection
Also one of the most popular types of connections, but for pipeline systems of small diameter (usually up to DN 50) and low pressures (up to 1.6 MPa). Very often found in household pipeline fittings, for example for. Its essence is simple: the pipe has a thread and the fittings have a thread, the latter is screwed onto the former.
You can cut threads on a pipe using special tools, if it does not exist and the equipment has not been installed previously. Threaded pipeline fittings at one end are made in the form of a hexagon for gripping with an adjustable wrench and screwing the fittings onto the pipe thread.
Video: how to cut a thread on a metal pipe and install a threaded ball valve
There are various options execution threaded connections: internal or external thread. The fittings may have an internal thread on one side and an external thread on the other, or the same type on both sides. There are also different thread standards, for example ISO 228/1 or DIN 2999. You need to take this into account when choosing.
The word “muff” comes from the Dutch word mouw, meaning “sleeve”.
To ensure the tightness of threaded types of connections, additional sealants are used in them - special FUM tapes, flax thread, as well as especially thick lubricants on top of them. All this is applied to the external thread.
Union connection
This is a subtype of threaded connection, which is used on taps of tiny sizes - up to DN 5. When connecting, the threaded fittings are tightened to the threads on the pipe with a union nut. Used for pipes for narrow purposes, such as laboratory pipes. Also used for implanting various measuring devices into pipelines.
Advantages of threaded connections for pipeline fittings
- Low price.
- They do not require additional parts for installation, such as the flange type.
- Easy to install, even easier to replace.
Flaws
- Not suitable for high pressures.
- The larger the diameter, the more effort must be applied to screw the fittings onto the threads with a seal.
Welded connection
If the ends of the pipeline fittings look simply like pipes without any additions, then they are connected to the system by welding. This is the most reliable and hermetically sealed connection, which, if done correctly, can result in absolute structural compliance of the materials. By welding a valve or tap to a pipe, you will not have to tighten the bolts, as with a flange connection, and the cost and weight of such fittings will be significantly less.
This type of connection can often be found on pipeline systems, transporting liquids and gases hazardous to health, where the slightest leaks cannot be allowed and absolute tightness is required. For a welded joint, the saying “set it and forget it” is typical. The main thing is to properly connect the pipe to the fittings so that the welding point is not weaker than the pipe wall.
The ends of the pipes must be prepared before welding, and each metal is prepared differently. We offer you a video with the most in a simple way welding
Advantages of a welded connection
- Absolute tightness correct execution welding procedures.
- Low cost of fittings.
- Light weight.
- Small size, the connection does not take up much space.
Flaws
- Qualified personnel are needed, which increases the final cost of installing such fittings.
- A labor-intensive dismantling process, such valves or taps must be installed once and for all.
Clamp quick release connection (Tri-Clamp)
Modern quick release coupling for pipeline fittings, mainly used in food industry, pharmacology and other industries where sterility and cleanliness are important. After all, this type of connection allows you to regularly remove, clean, and disinfect the equipment installed with this mount.
The clamp connection consists of two fittings, a seal and a clamp. The clamp presses the two fittings against the seal and against each other, resulting in a tight connection. We suggest you study what such a clamp is in the video.
Ball valve is one of the most popular types of pipeline fittings. One of its main classifying features is the method of attachment. “Coupled”, “flange”, “welded” are commonly used attachments for ball valves. Less commonly used are “pin”, “nozzle”, “nipple”, “solder”.
Types of connections for industrial pipeline fittings are defined in the current interstate standard GOST 24856-81 (analogous to ISO 6552-80). In the “description” cell of the GOST table of terms and definitions regarding types of connections there is a dash, there is only graphic sketch. It is understood that the meaning of the term should be clear literally from the name. However, for a person who is not interested in technology, the marking “socket ball valve” or “flanged ball valve” may be incomprehensible.
Ball valves by connection type
Coupling
The coupling ball valve is connected using internal threads cut into the body along the edges. A coupling is a connecting part of pipelines that has the shape of a hollow cylinder with a thread cut inside.
Socket ball valves are often used in both the domestic and industrial sectors. They are very convenient, since installation requires only a pair of wrenches (open-end, pipe, adjustable) depending on the installation location. To prevent leakage thread coupling valve packed with flax strands with unipak, FUM tape, sealing thread or anaerobic sealant. Installation of a coupling ball valve is quick, and the fittings themselves are relatively inexpensive. The most commonly used sizes are corresponding to the connecting thread ½, ¾, 1, 1 ¼, 1 ½, 2 inches. Also on the market there are smaller diameters - ¼, ⅜ inches, large ones - 2 ½, 3, 4 inches.
Flanged
The connection of a flanged ball valve is made in the form of a flat, most often round, part located perpendicular to the axis, with holes for fasteners (bolt and nut). There are always two flanges in the connection. One on the pipe, the second on the fittings. The flange connection is highly reliable. The thickness of the flange and the number of holes depends on the maximum pressure for which the ball valve is designed. In the domestic sector, flanged ball valves are practically not used, except for connecting to central water supply or gas pipeline. Such shut-off valves Mainly used in public utilities and industry.
Welded
Weld-on ball valves are mounted on the pipeline by welding. The connecting pipes of such fittings are made in the shape of a pipe and do not have threads or connecting parts. They are often also called (as GOST 24856-81 regulates) “ball valves for welding.” Weld-on ball valves can be made from carbon, low alloy, stainless steels, have a one-piece or collapsible design. The scope of application of welded fittings is industry and public utilities.
Fittings
Union ball valves are similar in design to coupling valves, with the only difference being that the thread on the connecting pipe is not internal, but external. The selection of a coupling or fitting product is made based on the thread on the mating part. Sellers, installers, and many manufacturers call such fittings “nipple taps,” which is the same thing. Their distinctive feature- connections with external thread. The price of a coupling ball valve is lower than that of a nipple valve. The installation and standard sizes of such fittings are mostly similar.
A ball valve with external thread can be equipped with half-bends on one or both sides. Such a connection will be dismountable and the valve can be removed for replacement or maintenance. The half fitting can be threaded or welded. A fitting with a half-fitting on one side is often called an “American tap”.
Tsapkovye
The pin-type ball valve has connecting pipes (one or both) with external threads and a collar. Such products are intended for installation directly on a tank, equipment (boiler, boiler), etc. An example of trunnion cranes can be seen below. For example, these are taps with a fitting for irrigation, water taps, drainage taps.
Solderable
Connection of ball valves is also possible by soldering. Basically, such fittings are installed on copper and polypropylene systems. The use of solder ball valves makes the connection more durable and aesthetically pleasing; the use of additional fittings is not required. It should be noted that it is correct to use the word “welding” when referring to polypropylene, but “soldering” is more often used among installers and consumers.
Names of ball valves
It just so happened that the standard established some terms for fittings, installers and designers use others, Chinese manufacturers- third. Here are some commonly used names and their meanings:
- ball valve NN - fittings on both sides with external thread (other names, “male-male”, “fitting on both sides”, “nipple”);
- ball valve BB - fittings on both sides with internal thread (“female-female”, “coupling”);
- ball valve VN on one side external thread on the other, internal (“father-mother”);
- faucet with a gander - pin-type water dismounting with a fitting for a hose;
- American tap - fittings with a collapsible connection (with a half-fitting).
Threaded and other shut-off valves can be the same type of connecting pipes or different - combined. For example, a ball valve on one side with internal thread, and on the other, external (VN). Or one connection is flanged and the other is welded.
Large selection of ball valves in our UniDim online store. Our brands are GIACOMINI, RBM, WATTS.
FEDERAL AGENCY FOR TECHNICAL REGULATION AND METROLOGY
NATIONAL
STANDARD
RUSSIAN
FEDERATION
Pipeline fittings ROTARY ACTION DRIVES Connecting dimensions
Industrial valves - Multi-turn valve actuator attachments
Industrial valves - Part-turn valve actuator attachments
Official publication
Standardinform
Preface
1 DESIGNED Closed joint stock company"Research and production company "Central Design Bureau of Valve Engineering" (JSC "NPF "TsKBA") based on ST TsKBA 062-2009 "Pipeline fittings. Rotary motion drives. Connecting dimensions"
2 8NESEN Technical Committee for Standardization TC 259 “Pipeline fittings and bellows”
3 APPROVED AND 8PUT INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated August 20, 2013 No. 529-Art.
4 This standard takes into account the main regulatory provisions of the following international standards:
ISO 5210 “Pipeline fittings. Connecting dimensions of multi-turn actuators" (ISO 5210 Industrial valves - Multi-turn valve actuator attachments", NEQ):
ISO 5211, “Pipeline fittings. Connecting dimensions of part-turn actuators" (ISO 5211 "Industrial valves - Part-turn valve actuator attachments", NEQ)
5 INTRODUCED FOR THE FIRST TIME
The rules for applying this standard are established by GOST R 1.0 - 2012 (section 8). Information on changes to this standard is published annually (as of January 1 of the current year) in the information index " National standards", and the official text of the changes and amendments is in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the next issue of the monthly information index “National Standards”. Relevant information, notices and texts are also posted information system public use- on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (gost.ru).
© Standardinform. 2014
This standard cannot be fully or partially reproduced, replicated or distributed as an official publication without permission from the Federal Agency for Technical Regulation and Metrology
1 ... 1 ... 1 ..2 16
1 Scope of application................................................... ...........................................
3 Terms and definitions................................................... ....................................
4 Types of connections................................................... ...........................................
5 Designation of connection types.................................................... ...................
Appendix A (mandatory) Connecting dimensions of multi-turn valves
drives for connection types MCH. MK. AC. AK. B. C. D. D...........................
Bibliography
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
Pipeline fittings
ROTARY DRIVES
Connection dimensions
Pipeline valves. Drives of rotary action The connecting dimensions
Date of introduction -2014-02-01
1 Application area
This standard applies to rotary actuators and actuators (hereinafter referred to as actuators) (multi-turn and part-turn, electric, pneumatic, hydraulic, as well as gearboxes) and establishes the types of connections of actuators to pipeline fittings, the connecting dimensions of actuators and the dimensions of counter connections of the pipeline fittings controlled by them .
2 Normative references
This standard uses normative references to the following standards:
GOST R 52720-2007 Pipeline fittings. Terms and definitions
GOST 22042-76 Studs for parts with smooth holes. Accuracy class B. Design and dimensions
3 Terms and definitions
In this standard the following terms are used with their corresponding
definitions:
3.3 multi-turn actuator: A device that imparts a torque to the valve sufficient for at least one revolution. May have the ability to withstand axial load (1].
3.4 part-turn actuator: A device that transmits torque by rotating its output element by one revolution or less, and does not have the ability to withstand an axial load.
3.5 gearbox: A mechanism designed to reduce the torque required to control pipeline fittings)
