When constructing highly reliable and economical pipelines, there is a need to install modern pipeline fittings. Fittings are an integral part of any pipeline system. In accordance with , pipeline fittings include devices designed to control media flows by disconnecting pipelines or sections thereof, distributing flows in the required directions, regulating various parameters of the environment, releasing the environment in the required direction by changing the flow area in the working body of the valve. These devices are mounted on pipelines, boilers, apparatus, units, tanks and other installations.
When choosing fittings, various requirements are imposed, and therefore, today there is great amount various designs, each of which represents a certain compromise between conflicting consumer requirements. All pipeline fittings can be divided into four main groups:
- Industrial fittings;
- Special purpose fittings;
- Ship fittings;
- Sanitary fittings.
Industrial pipeline fittings general purpose is used in various industries and is installed on water supply lines, steam pipelines, city gas pipelines and heating systems. Designed industrial fittings for environments with frequently used operating environment settings. Armature special purpose is operated under conditions of relatively high pressures and temperatures, at low temperatures, on corrosive, toxic, radioactive, viscous, abrasive or granular media. Target pipeline fittings include particularly important general industrial and special fittings, the use of which is regulated by special technical documentation. Often, special fittings are manufactured to individual orders based on specific technical requirements, and are used in experimental and unique installations. Ship fittings designed for operation in special operating conditions on river and river vessels navy. Ship fittings meet increased requirements in terms of minimum weight, vibration resistance, increased reliability, and specific conditions management and operation. Sanitary fittings installed on various household devices, such as gas stoves, bathroom installations, kitchen sinks and other plumbing fixtures. Basically, these fittings have small passage diameters and in most cases are operated manually.
The main operational characteristics of pipeline fittings include: nominal diameter, nominal pressure, operating temperature, valve tightness standards, throughput, climatic design and operating conditions, type of connection to the pipeline. The safety and efficiency of technological processes largely depends on well-chosen fittings and the correct operation of them.
Designation
This is a generally accepted, established name for fittings. The designation may be a table of figures (developed by TsKBA), drawing number, original factory designation, and so on. The most commonly used classification is Central design bureau valve engineering, according to which the symbol of the valve consists of sequentially repeated digital and alphabetic characters that determine the type and type of the valve, design, material design of the body, type and material of the seal in the valve, type of drive.
Let's consider this designation using the example of reinforcement 13ls963nzh
, Where:
13
- shut-off valve;
PM
- alloy steel;
9
- electric drive control;
63
- specific design;
nz
- surfacing in the stainless steel valve.
The first two digits indicate the type of fittings (valve, gate valve, faucet and other types). This is followed by one or two letters indicating the body material (cast iron, stainless steel etc). After which there are two or three digits. In the case of three digits, the first indicates the type of drive, and the rest indicate the serial number of the product in the catalog, depending on design features. If there are two numbers, then this valve is controlled manually. The last one or two letters in the designation indicate the material of the sealing surfaces or internal covering fittings.
Except symbols, a distinctive color was introduced for the fittings. Depending on the material, the outer untreated surfaces of cast iron and steel reinforcement, except for the drive, are painted in different colors.
Knowledge of the symbols and colors of fittings allows you to determine its type, conditions of use in pipelines and carry out proper control. Modern pipeline fittings meet high international standards and ensure uninterrupted operation of high-tech equipment, installations and pipelines in general.
Diameter, mm
Diameter, DN, nominal diameter, nominal size. Approximately equal internal diameter of the connected pipeline in millimeters. The diameter values must correspond to the numbers of the parametric series established by. The diameter is indicated through the fraction for part-bore fittings and those blocks whose diameter changes throughout its constituent elements.
Pressure, MPa
The pressure can be conditional - PN or working - Pр, measured in MPa. Nominal pressure PN - greatest overpressure at a working environment temperature of 20 C°. The values of the conditional pressures must correspond to the numbers of the parametric series established by. Operating pressure Pр - the highest excess pressure during normal operation, that is, the temperature of the working environment corresponds to normal conditions operation of fittings. The working pressure is equal to the nominal pressure at temperatures from – 15 to 120 C°; as the temperature increases, the working pressure decreases. Operating pressure is indicated only for special, energy, nuclear valves.
Type of fittings
Types of fittings structures that differ depending on the nature of the movement of the locking or control element relative to the direction of movement of the working fluid flow. The type of reinforcement is determined in accordance with.
Pipeline connection
Method of connecting fittings to a pipeline. The choice of method for connecting the fittings to the pipeline depends on the pressure, temperature of the working environment and the frequency of pipeline dismantling. There are plunger, combined, coupling, welding, coupling, flange, pin, and fitting connections of the fittings to the pipeline.
According to the method of sealing the movable elements of the shutter with a stationary part in the lid, relatively external environment There are gland, bellows, membrane and hose fittings.
Control type
Valve control method. Remote control – does not have a direct control element, but is connected to it using movable columns, rods, chains and other transition devices. Driven – control is carried out using an actuator installed directly on the valve. Working environment – control occurs without operator participation under the direct influence of the working environment on the locking element or sensitive sensor. Manual – control is carried out directly by the operator manually.
According to the principle of control and operation, pipeline fittings are divided into controlled and automatically operating fittings. Controlled valves can be equipped with manual drive, mechanical, electrical, pneumatic, hydraulic or electromagnetic drive.
Execution
The climatic operating conditions of the valves are determined in accordance with.
Housing material
The material from which the valve body is made. It should be remembered that the valve body may have an internal polymer coating, which means that there will be no correlation between the body material and chemical composition working environment.
Functional purpose
Functionally, pipeline valves are divided into shut-off, control, distribution and mixing, safety, protective and phase separating valves. Shut-off valves ensures shut-off of the flow of the working medium with a specified tightness. Shut-off valves include taps, valves, gate valves and butterfly valves. Shut-off valves are produced both with manual and with electric drive. Control valves is responsible for regulating the parameters of the working environment by changing the flow area. Control valves include motorized control valves, self-acting control valves, level controllers and steam traps. In action this type The valves are driven by a manual drive or a mechanical, hydraulic and electromagnetic drive. Distribution and mixing fittings designed to distribute and mix the flows of the working environment. These fittings include three-way taps and valves. Safety fittings designed to automatically prevent unacceptable excess pressure in the pipeline by releasing excess working fluid. Safety valves include safety and check valves, automatically releasing excess pressure into the atmosphere or automatically closing when flow movement occurs in reverse direction. Protective fittings designed to protect equipment from emergency changes in environmental parameters by disconnecting the service line or pipeline section. Phase separating fittings used to separate working environments located in different phase states. The phase separating fittings include a condensate trap that removes condensate and limits the passage of superheated steam.
Technical characteristics of RDUK
Notes 1. Regulators RDUK2N(V)-50 are not currently available. 2. First digit after letter designation regulator type - diameter of the connecting pipe D y, mm, the second is the diameter of the valve seat, mm.
The maximum throughput of RDUK2 regulators is shown in Fig. 1 where R 1 , R 2 — inlet and outlet pressure, respectively, kg/cm².
Design and operating principle of RDUK2N(V)-50
In the circuit of the pressure regulator RDUK2N(V)-50 (see Figures 1, 2), the control regulator KN2 is a command device, and the control valve is an actuator. The operation of the pressure regulator is carried out using the energy of the passing working medium.
The inlet pressure gas, in addition to the main valve, flows through the filter to the small valve of the control regulator and then through the connecting tube through the damping throttle - under the control valve membrane. Gas is discharged into the gas pipeline behind the pressure regulator through a relief choke.
Output gas pressure is supplied to the membranes of the control valve and the control regulator through connecting tubes. Due to the continuous flow of gas through the relief orifice, the pressure upstream of it and therefore below the control valve diaphragm is always greater than the outlet pressure.
The pressure difference on both sides of the control valve membrane forms the lifting force of the membrane, which, under any steady state operating mode of the regulator, is balanced by the weight of the moving parts and the action of the inlet pressure on the main valve.
The increased pressure under the control valve diaphragm is automatically regulated by the small valve of the control regulator, depending on the gas consumption and the inlet pressure before the regulator.
The output pressure force on the control regulator membrane is constantly compared with the force of the lower spring specified during adjustment; any slight deviation in output pressure causes the diaphragm and control valve to move. This changes the flow of gas passing through the small valve, and therefore the pressure under the control valve membrane.
Thus, for any deviation of the outlet pressure from the set point, the change in pressure under the large membrane causes the main valve to move to a new equilibrium position, at which the outlet pressure is restored. For example, if, as gas consumption decreases, the outlet pressure increases, the diaphragm and valve of the control regulator will lower slightly. In this case, the gas flow through the small valve will decrease, which will cause a decrease in pressure under the control valve membrane. The main valve, under the influence of inlet pressure, will begin to close until its flow area corresponds to the new gas consumption and the outlet pressure is restored.
During operation, the stroke of the diaphragm and valve of the control regulator required for full speed the main valve is very small, and the change in the forces of both springs at this small stroke, as well as the effect of the changing inlet pressure on the small valve, constitute an insignificant part of the effect of the outlet pressure on the control regulator diaphragm. This means that the regulator, when gas consumption and inlet pressure changes, maintains the outlet pressure due to a slight deviation from the set one. In practice, these deviations are approximately 1-5% of the nominal value.
Pressure regulators of the RDUK-2 type, developed by Mosgaz-project at the suggestion of engineer. F.F. Kazantsev, are intended to reduce gas pressure in gas pipelines from high to high, medium and low pressure, as well as from medium to medium and low.
Regulators can be used in looped and dead-end urban networks, regulatory stations, industrial and municipal gasified facilities.
These regulators are direct-acting regulators with a command device.
The supra-diaphragm space of the impulse tube control regulator is connected to the gas pipeline downstream of the pressure regulator. Thus, the pressure above the control regulator membrane is always equal to the gas pressure in the gas pipeline. Pressure regulators of the RDUK-2 type are designed for nominal diameters of 50, 100 and 200 mm. The pressure under the control regulator membrane is equal to atmospheric pressure. When the pressure in the gas pipeline is equal to the set one, the force from the gas pressure on the control regulator membrane is equal to the spring force. In this case, the control regulator valve is partially open.
When the pressure in the gas pipeline decreases, the spring overcomes the force from the gas pressure on the membrane, as a result of which the latter rises upward, increasing the opening of the valve. As the pressure increases, the valve opening decreases. Consumption; of gas flowing through the control regulator valve is proportional to its opening value. To set the control regulator to the required pressure, the spring compression is changed.
The control tube control head is connected to the sub-diaphragm space of the control valve, which is connected by a tube to the sub-valve space. For the control valve to operate, the pressure in the submembrane space must create a force greater than the sum of the forces created by the inlet pressure on the valve and the outlet pressure on the membrane in the supra-membrane space.
The necessary pressure difference between the sub-membrane and above-membrane spaces is created due to the presence of chokes in the tubes.
Control regulators KN2 and KV2 are used as a command device.
Pressure regulators of the RDUK-2 type are manufactured by the Moscow plant gas equipment and the Saratov Gazoapparat plant.
Currently, a new type of regulators is being produced - block designs by F. F. Kazantsev (RDBC). They are distinguished by their versatility and increased operational reliability. The unevenness of the outlet pressure when using the RDBK is less than when using the RDUK.
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| RDUK-200 |
RDUK is manufactured in the following versions:
- RDUK-50N(V) Du-50 with low or high output pressure and seat diameter 35 mm - RDUK-50N(V)/35;
- RDUK-100N(V) Du-100 with low or high output pressure and seat diameter 50, 70 mm - RDUK-100N(V)/50(70);
- RDUK-200N(V) Du-200 with low or high output pressure and seat diameter 105, 140 mm - RDUK-200N(V)/105(140).
The diameter of the seat affects the flow capacity of the regulator; the larger the seat, the greater the flow capacity of the regulator. The RDUK pressure regulator is designed for gas supply systems of various facilities. Installed in gas distribution stations (GRU, GRPSh, GRPB) of gas supply systems.
Longitudinal section and connection diagram of the RDUK-100 regulator.
Longitudinal section and connection diagram of the RDUK-200 regulator.
Control regulator KN-2
| Parameter name | RDUK2N(V)-50 | RDUK2N(V)-100 | RDUK2N(V)-200 | |
| Working environment | natural gas | |||
| Seat diameter, mm | 50/70 | 105/140 | ||
| Diameter conditional passage, Du | ||||
| Inlet pressure, MPa | 1,2 | |||
| Output pressure control limits, kPa | 0,5-60(60-600) | |||
| Maximum throughput, m³/h, not less | 12000/24500 | 47000/70000 | ||
| Accession | flanged according to GOST 12820-80 | |||
| dimensions, mm | ||||
| length | ||||
| width | ||||
| height | ||||
| Construction length L, mm | ||||
| Weight, kg |
Maintenance of the RDUK regulator. Before turning on the regulator, the pilot cup must be turned out until the spring is completely relaxed. All shut-off devices in front of the regulator and on impulse tube must be completely open. When turned on, first open the tap on the spark plug in order to ensure a small gas flow, and then slowly screw in the pilot adjusting cup. Its spring is compressed, and pressure appears at the controlled point, which is recorded on the pressure gauge. By further screwing in the glass, the outlet pressure is increased to approximately the specified value and gas flow is created. After this they produce more fine tuning regulator When the regulator is turned off long time The pilot adjusting cup is turned out until the spring is completely weakened.
To inspect the inlet part of the control valve, remove the top cover of the housing, remove the filter and the plunger with the rod. The filter is thoroughly cleaned of dust, washed and dried if necessary. The plunger, seat, column guide bushings, rod and pusher are wiped with a soft cloth, and the sealing washer of the plunger is replaced with a new one if there is visible wear. The plunger rod must move freely in the column bushings. The rod stroke is controlled through a plug in the bottom cover of the membrane box.
Lubrication of rubbing parts metal surfaces the regulator is allowed only if the gas is finely purified from mechanical impurities in a filter installed in front of the regulator.
The membrane is inspected with the bottom cover of the membrane box removed. Correct alignment of the membrane during assembly is ensured by installing the support cup in the annular groove of the bottom cover. During inspection, you should carefully blow out the chokes inside the special bolts.
To inspect the pilot control unit, unscrew the top plug of the cross and remove the plunger. If the blockage is severe, then unscrew the pressure sleeve of the seat, remove the seat with the gasket and blow out the internal cavity of the cross. When inspecting and assembling the membrane assembly, you should ensure that the plunger pusher with its sharp end is in the socket of the membrane coupling bolt, and that the lower end of the plunger pin falls into the upper conical recess of the pusher. If you press the membrane from below, you should first observe idling at least 2 mm, and then rise by 1.5-2 mm plunger. This degree of opening can be set by adjusting the length of the stud.
For a regulator with pilot KN2, when setting the output pressure to 0.02-0.03 kg/cm2, the control error can reach 15%; when setting to 0.5-0.6 kgf/cm2, it may be lower than 1-2%. In the latter case, unstable regulation is possible, and then it is necessary to reduce the sensitivity of the pilot by using the KV2 spring in it. In general, the possibility of unstable regulation increases with increasing inlet pressure and decreasing gas flow. To increase the stability of regulation, a choke with a diameter of 3, 4 or 6 mm is installed on tube b, respectively, for regulators Dy 50, 100 and 200 mm.
The reasons for the malfunction of the regulator during operation are: clogging of the pilot valve device, jamming of the KR plunger rod or pilot plunger stud, freezing of the plunger, clogging of the chokes on the regulator piping tubes.
Since clogging of the seat in the pilot and throttles is most often observed, the inspection should begin with them. The throttle, impulse and piping tubes of the regulator are thoroughly purged. If it is necessary to replace the pilot plunger stud, it is made from a straight piece of steel spring wire with a diameter of 1.4 mm. The ends of the pins are given a spherical shape.
Under operating conditions, the following problems occur: the pilot spring is completely weakened, but the outlet pressure reaches or exceeds 20 % nominal. The reason is a leak in the regulator's regulating body. The sealing surfaces of the seat and plunger are inspected and, if necessary, the latter is replaced rubber gasket:
The outlet pressure drops to zero. The reason is a rupture of the regulator membrane. The membrane is replaced; I - outlet pressure is continuously increasing. Reasons: rupture of the pilot membrane, clogging of the seat or jamming of the plunger pusher, pilot in the guides. Replace the membrane, clean the pilot seat and eliminate sticking of the pusher;
The output pressure, when adjusted within 0.2-J 0.6 kgf/cm 2, fluctuates greatly. A throttle should be installed on the tube 6, and if the oscillations persist, reduce the sensitivity of the KN2 pilot by using a spring from the KV2 in it;
The outlet pressure fluctuates greatly at low gas flow rates, regardless of the set pressure. The reason may be that the regulator capacity is too large. If vibration elimination is not achieved by installing a throttle on the tube 6, then reduce the inlet pressure, and if necessary, use a seat and regulator plunger of smaller sizes;
The outlet pressure gradually decreases, at times increases sharply and again decreases almost to zero. The reason is freezing of the plunger and pilot seat. Frosting can be eliminated by heating the pilot with a cloth moistened hot water;
The output pressure gradually decreases and preloading the pilot spring does not increase it. Reasons: clogging of the filter or pilot seat, loss of the sealing rubber of the plunger, breakage of the tuning spring. The filter should be cleaned, the seat should be cleaned and blown out, the rubber band and spring should be replaced with new ones; - the outlet pressure changes simultaneously with the change in the inlet pressure. Reasons: the installation locations of the chokes are mixed up d And d x or the throttles are not installed at all. You should check the presence of chokes and their correct installation.
9.2 Characteristics of main faults.
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Gas pressure regulator RDUK-50, RDUK-100, RDUK-200 designed to reduce gas pressure and automatically maintain output pressure within specified limits, regardless of changes in inlet pressure and gas flow. The regulator is used in gas supply systems of industrial, agricultural and municipal facilities.
Based on RDUK gas pressure regulators, we manufacture gas control points and gas control units of cabinet, block type or on a frame.
Available models RDUK-50, RDUK-100, RDUK-200:
RDUK manufactured in the following modifications:
RDUK-50N(V) Du-50 with low or high output pressure and a seat diameter of 35 mm - RDUK-50N(V)/35;
RDUK-100N(V) Du-100 with low or high output pressure and seat diameter of 50, 70 mm - RDUK-100N(V)/50(70);
RDUK-200N(V) Du-200 with low or high output pressure and seat diameter 105, 140 mm - RDUK-200N(V)/105(140).
Gas pressure regulators RDUK-200 Available in four versions:
- with low outlet pressure and seat diameter of 105 mm - RDUK 200 MN/105;
- with low outlet pressure and seat diameter of 140 mm – RDUK 200 MN/140;
- with high outlet pressure and a seat diameter of 105 mm - RDUK 200 MV/105;
- with high output pressure and a seat diameter of 140 mm - RDUK 200 MV/140.
Features of RDUK-50, RDUK-100, RDUK-200:
Bandwidth RDUK:
- RDUK 50 6500 m3/h
- RDUK 100 12000/24500 m3/h
- RDUK 200 47000/70000 m3/h
The climatic design complies with UZ GOST 15150 (from –45°C to +40°C). The gas pressure regulator RDUK 200 complies with the requirements of GOST 11881, GOST 12820 and a set of documentation in accordance with the specification RDUK 200M.00.00.00.
Technical and operational characteristics of regulators RDUK-50, RDUK-100, RDUK-200:
| Name of parameter or size | Values for type or version | |||||
| RDUK-2N-50 | RDUK-2N-100 | RDUK-2N-200 | ||||
| RDUK-2V-50 | RDUK-2V-100 | RDUK-2V-200 | ||||
| Nominal diameter of the inlet flange, DN | 50 | 100 | 200 | |||
| Seat diameter, mm | 35 | 50 | 70 | 105 | 140 | |
| Maximum input pressure, MPa (kgf/cm2) | 1,2 (12) | 1,2 (12) | 1,2 (12) | 0,6 (6) | ||
| Output pressure setting range, MPa (kgf/cm2) | for regulator low pressure | 0,005-0,06 (0,05-0,6) | ||||
| for regulator high pressure | 0,06-0,6 (0,6-6,0) | |||||
| Maximum throughput, m3/h, not less | 6000 | 12000 | 24500 | 37500 | 47000 | |
| Overall dimensions, mm | face-to-face length | 230 | 350 | 600 | ||
| width | 466 | 534 | 615 | |||
| height | 278 | 418 | 711 | |||
| Flanges (design and dimensions) according to GOST 12820-80 for nominal pressure MPa | 1,6 | |||||
| Weight, kg, no more | 15 | 50 | 282 | |||
Order Regulators RDUK-50, RDUK-100, RDUK-200
Type: universal pressure regulator.
The RDUK-2-50 regulator is designed to reduce gas pressure and automatically maintain a given outlet pressure and installation in gas control points (GRP), gas control units (GRU).
The regulator provides a reduction in gas inlet pressure and automatically maintains a set outlet pressure regardless of changes in gas flow and inlet pressure.
The gas regulator RDUK-2-50 is used in gas supply systems for industrial, agricultural and municipal facilities.
Basic technical data of the RDUK-2-50 regulator
Type: universal gas pressure regulator.
Climatic version: U2 GOST 15150-69.
Ambient temperature: from minus 45 to plus 40 0 C.
Weight: 15 kg.
| Name of parameter or size | RDUK-2N-50 | RDUK-2V-50 |
| Nominal diameter of the inlet flange, DN mm | 50 | 50 |
| Seat diameter, mm | 25 | 35 |
| Maximum input pressure, MPa (kgf/cm2) | 1,2 (12) | 1,2 (12) |
| Output pressure setting range, MPa (kgf/cm2) | 0,005—0,06 (0,005—0,6) | 0,06—0,6 (0,6—6,0) |
| Maximum throughput, m 3 / h | 6000 | 6000 |
Design and principle of operation of the RDUK-2-50 regulator
Overall dimensions of the gas pressure regulator RDUK-2-50
| Regulator type | construction length, mm | width, mm | height, mm |
| RDUK-2N-50 | 230 | 466 | 278 |
| RDUK-2V-50 | 230 | 466 | 278 |
The gas pressure regulator RDUK-2-50 consists of two main components - control valve 5 and pilot 20. A diaphragm drive is attached to the lower part of the housing. The pusher 6 rests against the central seat of the plate, and the valve stem 7 rests against it, transmitting the vertical movement of the membrane plate 3 to the regulator valve. The rod moves in the guide column of the housing 4; a valve with a rubber seal 8 sits freely on the upper end of the rod. The housing is closed on top with a lid.
The KN-2 or KV-2 pilot plays the role of a command device in the pressure regulator piping circuit. The pilot consists of a housing 11, a cover 12, a membrane 15 sandwiched between them, a valve 21, a tuning spring 14 and an adjusting cup 13.
The inlet pressure gas enters the pilot from the top of the housing. After throttling in the pilot, gas through tube 17 enters the sub-membrane space of the control valve through a calibrated hole into damping throttle 1. Excess gas from the sub-membrane space is constantly discharged into the gas pipeline after the regulator through tube 18 through a throttle installed on the gas pipeline. Appropriate selection of the diameters of the throttles 1 and the throttle on the gas pipeline in the presence of a continuous gas flow through tubes 17 and 18 makes it possible to constantly maintain a pressure slightly higher than the output pressure in the sub-membrane space of the control valve. This pressure difference on both sides of the membrane 3 forms its lifting force, which is balanced at any steady state of operation of the regulator by the weight of the moving parts and the action of the inlet pressure on the valve 8.
The compression of the pilot spring 14, which determines the value of the gas outlet pressure, is carried out by screwing in the adjusting cup 13. The greater the outlet pressure should be, the more the spring should be compressed. When the regulator is not operating, the spring must be weakened.
With an increase in gas extraction from the gas pipeline, its pressure after the regulator and under the membrane of pilot 15 and the control valve will decrease. The pilot membrane, under the action of the spring 14, will lower and, through the pusher 10, press on the pilot valve 21, compressing the spring 9 located above it. The pilot seat will open slightly more, the flow of gas into the sub-diaphragm space of the control valve and its pressure from below on the membrane 3 will increase. The membrane, rising, will increase the valve lift and gas flow through the regulator.
As gas extraction from the gas pipeline decreases, its pressure after the regulator and under the membrane of pilot 15 and the control valve will increase. The pilot diaphragm will rise and block the flow of gas through the pilot valve into the sub-diaphragm space of the control valve. The gas pressure under the membrane 3, as a result of its discharge through the tube 18, will decrease, and the membrane, under the influence of the increasing pressure of the gas above it, will drop, and the control valve will reduce the gas supply through the regulator.
The pressure difference on both sides of the membrane creates a lifting force of the membrane, which, in any steady state operation of the control regulator, is balanced by the weight of the moving parts and the inlet gas pressure on the valve.
When the outlet gas pressure decreases, the pressure in the space above the membrane will also increase, while in the space below the membrane it will not change. As a result, the membrane rises and opens the valve.
As the outlet gas pressure increases, the pressure in the space above the membrane will also increase, while in the space below the membrane it will not change. As a result, the membrane will lower and close the valve. Thus, for any deviation of the output pressure from the set one, the change in pressure in the space above the membrane will cause the valve to move to a new equilibrium position, at which the output pressure will be restored.
Indication of safety measures when working with the pressure regulator RDUK-2-50
The RDUK-2-50 regulator must be installed on gas pipelines with pressures corresponding to those specified in the technical specifications.
Installation and switching on of the RDUK-2-50-2 pressure regulator must be carried out by a specialized construction, installation and operational organization in accordance with the approved project, technical specifications for construction and installation work, “safety rules in the gas industry.”
Elimination of defects when inspecting regulators must be carried out without pressure.
During testing, the increase and decrease in pressure should be carried out smoothly.
Preparing the pressure regulator RDUK-2-50 for operation
Before starting the pressure regulator, the following steps must be carried out: General requirements training and safety precautions, provided for by the instructions upon startup of a gas control point or gas control unit.
Placement and installation of the RDUK-2-50 regulator
The pressure regulator RDUK-2-50-2 is mounted on a horizontal section.
The connection of the impulse pipeline 19 and tubes 16 and 18 from the membrane chamber to the main gas pipeline can be carried out in various ways:
The impulse tube 19 is connected to the middle of a straight section of the gas pipeline after the regulator with a length of ≈10 of its diameters. The total length of the tube should not exceed 6 m. Tubes 16 and 18 are connected to the gas pipeline after the regulator in a section of ≈100 mm in length.
Pulse tube 19 is connected to the middle part of the straight section of the hydraulic fracturing bypass, tubes 16 and 18 are connected to the gas pipeline after the regulator in a section ≈100 mm long.
Tubes 19, 16 and 18 are connected to a special pipe, which is welded to the gas pipeline after the regulator at a distance of at least 5 of its diameters from the nearest turn.
Before starting, the adjusting screw of the control regulator (pilot) must be turned out until the spring is completely weakened.
For the low pressure regulator, it is necessary to check the installation of the replacement spring for the required range of regulated outlet pressure.
Operating procedure.
When the pilot spring is completely weakened, the regulator is started by gradually screwing in the pilot adjusting cup.
The required gas outlet pressure is set using a pressure gauge.
For stable operation When starting the regulator, it is recommended to ensure a minimum gas flow after it to the purge plug.
To create flow through the regulator, it is advisable to use not the candle closest to the regulator, but the one farthest (if there is more than one candle). In this case, the regulator is adjusted to a more difficult operating mode.
After the spark plug there should not be a section of the gas pipeline that is closed during setup and startup. In this case, it acts as a gas accumulator, which negatively affects the adjustment conditions of the regulator and can lead to fluctuations in gas pressure during adjustment.
Maintenance of regulator RDUK-2-50
The RDUK-2-50 regulator is subject to inspection of its technical condition and current repairs according to the approved schedule in accordance with the requirements of PB-12-529-03.
Inspection of technical condition is carried out as follows:
To inspect the RDUK-2-50-2 control valve, it is necessary to remove the top cover, the valve with the stem and clean them. The valve seat and guide bushings should be thoroughly wiped. The sealing edge of the seat should be carefully inspected. If there are nicks and deep scratches the seat should be replaced. The valve stem must move freely in the column. To inspect the membrane, you must remove the bottom cover. The membrane must be wiped.
Typical malfunctions of RDUK-2-50 gas pressure regulators and methods for eliminating them
Violation of the operating mode of the RDUK-2-50-2 regulator during operation most often occurs when the main valve stem gets stuck, as well as when the chokes on the regulator piping pipes become clogged.
The pilot spring is completely weakened, but the output pressure increases. The reason is a leak in the main valve. The solution is to replace the valve.
The outlet pressure drops to zero. The reason is a membrane rupture. Replace the membrane.
The outlet pressure fluctuates greatly at low gas flow rates, regardless of the set pressure. It can be eliminated by installing a throttle control valve with a diameter of 3, 4 or 6 mm, respectively, for regulators DN 50, 100, 200 mm on pipe 16 to the above-membrane cavity. If vibration elimination cannot be achieved by installing a throttle on the tube, then reduce the inlet pressure and, if necessary, replace the seat and valve with smaller sizes.
