The word "flange" came into Russian from German language together with the flange itself, and was not assigned on the basis of some analogies. In German, the noun Flansch means exactly the same thing as its derivative Russian word“flange”, ─ a flat metal plate at the end of a pipe with holes for threaded fasteners (bolts or studs with nuts). It is more usual when this plate is round, but the shape of the flanges is not limited to one disk. For example, square and triangular flanges are used. But round ones are easier to make, so the use of rectangular or triangular flanges can be justified for really good reasons.
The material, types and design features of the flanges are determined by the nominal diameter, pressure of the working medium and a number of other factors.
For the manufacture of flanges of pipeline fittings, gray and malleable cast iron are used, different varieties become.
Ductile iron flanges are designed for higher pressures and a wider temperature range than gray iron flanges. Cast steel flanges are even more resistant to these factors. Steel welded, just as easy to transfer high temperatures, are inferior to cast flanges in the maximum allowable pressure.
The design features of the flanges may be the presence of protrusions, chamfers, spikes, annular selections, etc.
The prevalence of flanged pipe fittings is due to their many inherent advantages. The most obvious of them is the possibility of multiple assembly and disassembly. The temptation to add the adjective “light” to the noun “installation” is somewhat reduced if we remember how many bolts will need to be unscrewed and tightened when disassembling and joining large diameter flanges (flange connections are usually used for pipes with a diameter of 50 mm or more). Although in this case the complexity installation work will not go beyond reason.
Flange connections are durable and reliable, which allows them to be used to complete pipeline systems operating under high pressure. Under a number of conditions, flanged connections provide very good tightness. To do this, the butted flanges must have similar connecting dimensions that do not go beyond the permissible error. Another of the conditions is the mandatory periodic tightening of the joints, which allows maintaining the "grip" of bolted joints at the proper level. This is especially important when they are constantly exposed to mechanical vibrations or there are significant fluctuations in temperature and humidity. environment. And than larger diameter pipeline, the more relevant it is, because as it increases, the force on the flanges increases. The tightness of flange connections largely depends on the sealing ability of the gaskets installed between the flanges.
Deformations cannot be discounted. Moreover, flanges made of different materials, are subject to them to an unequal degree, therefore the material from which it is made is the most important parameter of the flange. Thus, ductile steel flanges deform more easily than those made of more brittle, but much better shape-holding cast iron.
The disadvantages of flanged fittings are a continuation of its advantages. High strength turns into significant overall dimensions and mass, which, in turn, mean an increased consumption of metal (in the manufacture of large-sized flanges, you have to use a thick a metal sheet or round profiles large diameter) and the complexity of production.
Weld fittings
Reinforcement welding is resorted to when the reliability and tightness of other types of joints is considered unsatisfactory. Welding is especially in demand in the construction of pipeline systems in which the working medium is toxic, poisonous or radioactive liquids and gases. In this case, a welding joint that, when properly designed, provides 100% tightness, may be the optimal, and often the only acceptable solution. It is only important that such a section of the system does not need frequent dismantling of the equipment, the implementation of which every time will lead to the complete destruction of the welded joints.
Thanks to welding, which unites the fragments of the pipeline system into a single whole, it is possible to ensure harmony, or, in technical terms, structural compliance between all its elements ─ pipes and pipeline fittings. The main thing is that because of the differences mechanical properties welded joint and other components of the pipeline system, it did not become its weak link.
The connecting ends of the reinforcement are prepared for welding by leveling and grinding the surface of the fragments to be welded, removing the required chamfers.
Welded joints can be made in the socket and butt. In the first case, the weld is located on the outside of the pipe. This option is usually used for steel fittings of relatively small diameter, mounted in pipelines operating at high pressure and temperature of the working medium.
In the second case, the connection can be supplemented with a backing ring, which excludes distortion of the connected parts. It is these connections, distinguished by reliability and absolute tightness, that are used in the installation of pipeline systems of hazardous production facilities, for example, power units of nuclear power plants.
Important advantages of welded joints, especially in comparison with flanged ones, are minimal weight, compactness and space saving.
Coupling fittings
One of the most common in technology is the coupling connection of reinforcement.
It is used for various types fittings of small and medium diameter, operating at low and medium pressures, the body of which is made of cast iron or non-ferrous metal alloys. If the pressure is high, then it is preferable to use a pin fitting.
In the connecting pipes of coupling fittings, the thread is located with inside. As a rule, this pipe thread─ inch thread with fine pitch. She is being shaped different ways─ knurling, cutting, stamping. It is important that with a fine thread pitch, the height of the teeth does not depend on the diameter of the pipeline.
Outside, the connecting ends are designed in the form of a hexagon, so that it is convenient to use the key.
The word "coupling" came into Russian from German, and possibly from Dutch, Where mouw means sleeve. A coupling, like a valve, is an example of how tailoring and the production of pipeline fittings each use words that sound the same in their special terminology, but carry a different semantic load. In technology, a sleeve is not called a sleeve, but a short metal tube that provides connections for the cylindrical parts of machines.
The fine thread of the coupling joint plus the use of special viscous lubricants, linen strands or fluoroplastic sealing material (FUM tape) guarantee its high tightness. The sleeve connection does not require the use of additional fasteners (for example, bolts or studs, as in a flange connection). But it must be taken into account that screwing the coupling onto a thread with a seal requires considerable effort, the greater the greater the diameter of the pipeline.
Choke fittings
The German origin of the term "fitting" from the verb stutzen (cut, cut) even betrays its sound. So because of the presence of a rifled barrel, the muskets used to arm armies were called until the 19th century. In modern technology, this noun is used to define a short piece of pipe (in other words, bushings) with threads at both ends, which serves to connect pipes and pipeline fittings to units, installations and tanks. In a union connection, the connecting end of the fitting with an external thread is pulled to the pipeline by means of a union nut. It is used for fittings of small and extra small (with a nominal diameter up to 5.0 mm) diameters. As a rule, these are laboratory or other special fittings. For example, gearboxes mounted on compressed gas cylinders. With the help of a nipple connection, various control and measuring instruments (CIP) are “implanted” into pipeline networks, evaporators, thermostats, and many types of equipment that are part of chemical production process lines are mounted.
Tie-down fittings
The term "trunnion connection" came into wide use at the end of the 19th century. Its main attributes for pipeline fittings are connecting pipes with external thread and the presence of a collar. The end of the pipeline with a collar is pressed against the end of the valve branch pipe with a union nut.
Toe connection is used for rebar high pressure small sizes in particular instrumentation. It is effective when screwing fittings into the body of vessels, apparatuses, installations or machines. Its tightness is ensured by the presence of gaskets and special lubricants.
An example of a pin connection is the connection of a fire hose to a fire hydrant.
All threaded connections are characterized by such advantages as minimal amount connecting elements, low metal consumption and, accordingly, low weight, manufacturability. Efficient Installation threaded connections requires matching internal and external threads, the use of soft or viscous materials for sealing. But it should be borne in mind that threading reduces the thickness of the pipe wall, so this type of connection is not well suited for thin-walled pipes.
In addition to those listed, there are other ways to attach reinforcement. So, in pipeline systems, durite compounds can be used. These are connections by means of cylindrical couplings, consisting of several layers of rubberized fabric (in simple terms, fragments of hoses), which are pushed onto the protrusions made on the nozzles and fixed with metal clamps.
Another way to attach reinforcement is soldering, which is used to copper pipes with small diameter. The end of the pipeline treated with solder is inserted into the groove made in the branch pipe.
The functionality, performance and reliability of the pipeline system is determined not only by the parameters of the fittings included in it, but also by how welldone rebar connection , the selection and implementation of which should always be given increased attention.
FEDERAL AGENCY FOR TECHNICAL REGULATION AND METROLOGY
NATIONAL
STANDARD
RUSSIAN
FEDERATION
Pipe fittings ROTARY ACTUATORS Mounting dimensions
Industrial valves - Multi-turn valve actuator attachments
Industrial valves - Part-turn valve actuator attachments
Official edition
Standartinform
Foreword
1 DEVELOPED by Closed Joint Stock Company “Scientific and Production Company “Central Design Bureau of Valve Engineering” (CJSC “NPF “TsKBA”) based on ST TsKBA 062-2009 “Pipeline fittings. Rotary drives. Connecting dimensions»
2 8NESEN Technical committee for standardization TC 259 "Pipe fittings and bellows"
3 APPROVED AND 8PUT INTO EFFECT by the Order of the Federal Agency for Technical Regulation and Metrology of August 20, 2013 No. 529-st.
4 This standard takes into account the main regulatory provisions of the following international standards:
ISO 5210 Pipe fittings. Mounting dimensions of multi-turn actuators "(ISO 5210 Industrial valves - Multi-turn valve actuator attachments", NEQ):
ISO 5211, “Pipe fittings. Mounting dimensions of part-turn actuators" (ISO 5211 "Industrial valves - Part-turn valve actuator attachments", NEQ)
5 INTRODUCED FOR THE FIRST TIME
The rules for the application of this standard are established by GOST R 1.0 - 2012 (section 8). Information about changes to this standard is published in the annual (as of January 1 of the current year) information index "National Standards", and the official text of changes and amendments - in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the next issue of the monthly information index "National Standards". Relevant information, notification and texts are also placed on the information system common use- on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (gost.ru).
© Standartinform. 2014
This standard cannot be fully or partially reproduced, replicated and distributed as an official publication without the permission of the Federal Agency for Technical Regulation and Metrology
1 ... 1 ... 1 ..2 16
1 area of use............................................... .........................................
3 Terms and definitions .......................................................... ................................................
4 Connection types............................................................... .........................................
5 Designation of connection types............................................................... ...................
Annex A (mandatory) Mounting dimensions of multi-turn
drives for types of connections MCH. MK. AC. AK. B. W. D. D ..........................
Bibliography
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
Pipe fittings
ROTARY DRIVES
Mounting dimensions
pipeline valves. Drives of rotary action The connecting dimensions
Introduction date -2014-02-01
1 area of use
This standard applies to rotary actuators and actuators (hereinafter referred to as actuators) (multi-turn and semi-rotary, electric, pneumatic, hydraulic, as well as gearboxes) and establishes the types of actuator connections to pipeline valves, the connecting dimensions of the actuators and the dimensions of the mating connections of the pipeline valves controlled by them .
2 Normative references
This standard uses normative references to the following standards:
GOST R 52720-2007 Pipe fittings. Terms and Definitions
GOST 22042-76 Studs for parts with smooth holes. Accuracy class B. Design and dimensions
3 Terms and definitions
For the purposes of this standard, the following terms are used with their respective
definitions:
3.3 multi-turn actuator May have the ability to withstand axial load (1).
3.4 part-turn actuator: A device that transmits torque when its output element is rotated one revolution or less, not having the ability to withstand an axial load.
3.5 gearbox
