Gas pressure regulator cylinder RDG. Gas pressure regulators

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Installation

Type: gas pressure regulator.

The RDG-80 regulator is intended for installation in gas control points of gas distribution systems of urban and rural gas supply systems settlements, in hydraulic fracturing and gas control units of industrial and municipal enterprises.

The RDG-80 gas 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 RDG-80 as part of gas control points for hydraulic fracturing is used in gas supply systems for industrial, agricultural and municipal facilities.

The operating conditions of the regulators must correspond to the climatic version U2 of GOST 15150-69 with the ambient temperature:

From minus 45 to plus 40 °C in the manufacture of body parts from aluminum alloys;

From minus 15 to plus 40 °C in the manufacture of body parts made of gray cast iron.

Stable operation of the regulator at given temperature conditions is ensured by the design of the regulator.

For normal operation ori negative temperatures environment it is necessary that the relative humidity of the gas when it passes through the regulator valves is less than 1, i.e. when moisture loss from the gas in the form of condensate is excluded.

The warranty period is 12 months.

Service life - up to 15 years.

Main technical characteristics of the RDG-80 regulator

Connection to the pipeline: flange according to GOST-12820.

Regulator operating conditions: U2 GOST 15150-69.

Ambient temperature: from minus 45 °C to plus 60 °C.

Regulator weight: no more than 60 kg.

Unevenness of regulation: no more than +- 10%.

Size parameter name	RDG-80N	RDG-80V
Nominal diameter of the inlet flange, DN, mm
Maximum input pressure, MPa (kgf/cm2)	1,2 (12)
Output pressure setting range, MPa	0,001-0,06	0,06-0,6
Seat diameter, mm	65; 70/24*
Range of adjustment of the response pressure of the automatic shutdown device RDG-N when the outlet pressure decreases, MPa	0,0003-0,003
Range of adjustment of the response pressure of the automatic shutdown device RDG-N when the outlet pressure increases, MPa	0,003-0,07
Range of adjustment of the response pressure of the automatic shutdown device RDG-V when the outlet pressure decreases, MPa	0,01-0,03
Range of adjustment of the response pressure of the automatic shutdown device RDG-V when the outlet pressure increases, MPa	0,07-0,7
Connecting dimensions of the inlet pipe, mm	80 GOST 12820-80
Connecting dimensions of the outlet pipe, mm	80 GOST 12820-80

* - The DN 80 regulator is manufactured with a single seat as standard, a double seat is available upon request.

Design of the gas pressure regulator RDG-80 and principle of operation

The RDG-80N and RDG-80V regulators include the following main assembly units:

Actuator;
- control regulator;
- control mechanism;
- stabilizer (for RDG-N).

1. control regulator; 2. control mechanism; 3. body; 4. shut-off valve; 5. valve working; 6. non-adjustable throttle; 7. saddle; 8. adjustable throttle; 9. working membrane; 10. actuator rod; 11. impulse tube; 12. control mechanism rod.

regulator RDG-80V composition

regulator RDG-80N composition

The actuator has a flanged body, inside of which a replaceable seat is installed. A membrane drive is attached to the lower part of the housing, which consists of a membrane, into the central socket of which a pusher rests, and against it is a rod that moves in the bushings of the guide column and transmits the vertical movement of the membrane to the control valve.

The control regulator generates control pressure for the sub-membrane cavity of the membrane drive of the actuator in order to move the control valve.

Using the adjusting glass of the control regulator, the RDG-80 pressure regulator is adjusted to the specified output pressure.

The stabilizer is designed to maintain constant pressure at the inlet to the control regulator (pilot), i.e. to eliminate the influence of input pressure fluctuations on the operation of the regulator as a whole and is installed only on low output pressure regulators RDG-N.

The stabilizer and control regulator (pilot) consist of: a housing, a membrane assembly with a spring load, a working valve, and an adjustment cup.

To control the pressure, an indicator pressure gauge is installed after the stabilizer.

The control mechanism is designed to continuously monitor the output pressure and issue a signal to operate shut-off valve in the actuator during emergency increases and decreases in output pressure above the permissible specified values.

The control mechanism consists of a detachable housing, a membrane, a rod, a large and a small adjustment spring, which balance the action of the output pressure pulse on the membrane.

The shut-off valve has a bypass valve, which serves to equalize the pressure in the cavities of the actuator body before and after the shut-off valve when starting the regulator.

The filter is designed to clean the gas used to control the regulator from mechanical impurities.

The RGD-80 regulator is working as follows. The inlet pressure gas flows through the filter to the stabilizer, then under a pressure of 0.2 MPa into the control regulator (pilot) (for the RDG-N version). Text copied from www.site. From the control regulator (for the RDG-N version), gas flows through an adjustable throttle into the submembrane cavity of the actuator. The above-membrane cavity of the actuator is connected to the gas pipeline behind the regulator through an adjustable throttle and a pulse tube of the inlet gas pipeline.

The pressure in the submembrane cavity of the actuator during operation will always be greater than the output pressure. The supra-membrane cavity of the actuator is under the influence of output pressure. The control regulator (pilot) maintains a constant pressure, so the pressure in the submembrane cavity will also be constant (in steady state).

Any deviation of the output pressure from the set one causes changes in the pressure in the above-membrane cavity of the actuator, which leads to the movement of the control valve to a new equilibrium state corresponding to the new values of the input pressure and flow rate, while the output pressure is restored.

In the absence of gas flow, the valve is closed, which is determined by the absence of a control pressure difference in the above-membrane and submembrane cavities of the actuator and the action of the inlet pressure.

If there is a minimum gas consumption, a control difference is formed in the above-membrane and sub-membrane cavities of the actuator, as a result of which the membrane of the actuator with a rod connected to it, at the end of which the working valve sits freely, will move and open the passage of gas through the gap formed between the valve seal and saddle

With a further increase in gas flow, under the influence of the control differential pressure in the above-mentioned cavities of the actuator, the membrane will begin to move further and the rod with the working valve will begin to increase the passage of gas through the increasing gap between the seal of the working valve and the seat.

When the gas flow rate decreases, the valve, under the influence of a changed control differential pressure in the cavities of the actuator, will reduce the passage of gas through the decreasing gap between the valve seal and the seat, and in the absence of gas flow, the valve will close the seat.

In the event of emergency increases and decreases in output pressure, the membrane of the control mechanism moves to the left or right, the rod of the control mechanism disengages from the stop through the bracket and releases the levers associated with the shut-off valve rod. The shut-off valve, under the action of a spring, blocks the gas inlet into the regulator.

Throughput of regulators RDG-80N and RDG-80V Q m 3 /h saddle 65 mm, p = 0.72 kg/m 3

Pvx, MPa	Rout, kPa
Pvx, MPa	2…10	30	50	60	80	100	150	200	300	400	500	600
0,10	2250	2200	1850	1400
0,15	2800	2800	2800	2750	2600	2350
0,20	3400	3400	3400	3400	3350	3250	2600
0,25	3950	3950	3950	3950	3950	3950	3650	2850
0,30	4500	4500	4500	4500	4500	4500	4450	4000
0,40	5600	5600	5600	5600	5600	5600	5600	5600	4650
0,50	6750	6750	6750	6750	6750	6750	6750	6750	6500	5250
0,60	7850	7850	7850	7850	7850	7850	7850	7850	7850	7300	5750
0,70	9000	9000	9000	9000	9000	9000	9000	9000	9000	8850	8050	6200
0,80	10100	10100	10100	10100	10100	10100	10100	10100	10100	10100	9750	8700
0,90	11200	11200	11200	11200	11200	11200	11200	11200	11200	11200	11150	10550
1,00	12350	12350	12350	12350	12350	12350	12350	12350	12350	12350	12350	12100
1,10	13450	13450	13450	13450	13450	13450	13450	13450	13450	13450	13450	13400
1,20	14600	14600	14600	14600	14600	14600	14600	14600	14600	14600	14600	14600

Overall dimensions of the gas pressure regulator RDG-80

Regulator brand	Length, mm	Construction length, mm	Width, mm	Height, mm
RDG-80N	670	502	560	460
RDG-80V	670	502	560	460

Operation of the RDG-80 regulator

The RDG-80 regulator must be installed on gas pipelines with pressures corresponding to its technical characteristics.

Installation and switching on of regulators 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, the requirements of SNiP 42-01-2002 and GOST 54983-2012 “Gas distribution systems. Natural gas distribution networks. General requirements for use. Operational documentation".

Elimination of defects when inspecting regulators should be carried out without pressure.

During the test, the increase and decrease in pressure should be carried out smoothly.

Preparation for installation. Unpack the regulator. Check the completeness of the delivery.

Remove grease from the surfaces of the regulator parts and wipe them with gasoline.

Check the RDG-80 regulator by external inspection for absence mechanical damage and safety of seals.

Placement and installation.

The RDG-80 regulator is mounted on a horizontal section of the gas pipeline with the membrane chamber facing down. The connection of the regulator to the gas pipeline is flanged in accordance with GOST 12820-80.

The distance from the bottom cover of the membrane chamber to the floor and the gap between the chamber and the wall when installing the regulator in the gas distribution unit and gas distribution unit must be at least 300 mm.

The impulse pipeline connecting the pipeline to the sampling point must have a diameter of DN 25, 32. The connection point of the impulse pipeline must be located on top of the gas pipeline and at a distance from the regulator of at least ten diameters of the outlet pipe of the gas pipeline.

Local narrowing of the flow area impulse pipe are not allowed.

The tightness of the actuator, stabilizer 13, control regulator 21, control mechanism 2 is checked by starting the regulator. In this case, the maximum input and output pressure for a given regulator is set, and the tightness is checked using a soap emulsion. Pressure testing of the regulator with a pressure value higher than that specified in the passport is unacceptable.

Work order.

Before the RDG-80 regulator is installed technical pressure gauge TM 1.6 MPa 1.5 for measuring the inlet pressure.

On the outlet gas pipeline, near the insertion point of the impulse tube, a two-pipe pressure and vacuum gauge MV-6000 or a pressure gauge is installed when operating at low pressures, as well as a technical pressure gauge TM-0.1 MPa - 1.5 when operating at medium gas pressure.

When the RDG-80 regulator is put into operation, control regulator 1 is adjusted to the value of the given output pressure of the regulator, reconfiguration of the regulator from one output pressure to another is also carried out by control regulator 11, while by screwing in the adjusting cup of the control regulator diaphragm spring, we increase the pressure, and turning away - lowering.

When self-oscillations appear in the operation of the regulator, they are eliminated by adjusting the throttle. Before putting the regulator into operation, it is necessary to open the bypass valve using the shut-off device lever; arm automatic shutdown devices; the bypass valve will close automatically. If necessary, resetting the upper and lower limits of the shut-off valve's response pressure is done using the large and small adjusting nuts, respectively; by tightening the adjusting nut, we increase the response pressure, and by unscrewing, we lower it.

Maintenance. The RDG-80V and RDG-80N regulators are subject to periodic inspection and repair. Text copied from www.site. The period of repairs and inspections is determined by the schedule approved by the responsible person.

Technical inspection of the actuator. To inspect the control valve, you need to unscrew the top cover, remove the valve with the stem and clean them. The valve seat and guide bushings should be thoroughly wiped.

If there are nicks and deep scratches the seat should be replaced. The valve stem must move freely in the column bushings. To inspect the membrane, you must remove the bottom cover. The membrane must be inspected and wiped. It is necessary to unscrew the throttle needle, blow it out and wipe it.

Inspection of the stabilizer 13. To inspect the stabilizer, unscrew the top cover, remove the membrane assembly and valve. The membrane and valve must be wiped. When inspecting and assembling the membrane, the sealing surfaces of the flanges should be wiped. Inspection of the control regulator is carried out similarly to inspection of stabilizer 13.

Inspection of the control mechanism. Unscrew the adjusting nuts, remove the springs and the top cover. Inspect and wipe the membrane. Make sure the valve seal is intact. If necessary, replace the membrane. Wipe the sealing surfaces of the housing and cover.

Possible malfunctions of the RDG-80 regulator and methods for eliminating them

Name of the malfunction, external manifestation and additional signs	Probable Causes	Elimination method
The shut-off valve does not provide a tight seal.	Breakage of the shut-off valve spring. Rupture of the shut-off valve seal by the gas flow. Worn seal or damaged shut-off valve.	Replace faulty parts.
The shut-off valve does not operate consistently. Cannot be adjusted.	Breakage of the large spring of the control mechanism.
The shut-off valve does not operate when the outlet pressure drops.	Breakage of the small spring control mechanism.	Replace the spring, adjust the control mechanism.
The shut-off valve does not operate during emergency increases and decreases in output pressure.	Rupture of the control mechanism membrane.	Replace the membrane, adjust the control mechanism.
As the outlet pressure increases (decreases), the outlet pressure sharply increases (decreases).	Rupture of the actuator membrane. Wear of sealing gaskets of control valves. Rupture of the stabilizer membrane. Rupture of the control regulator membrane.	Replace faulty membranes, gaskets, seat.

Technical characteristics of RDG-50N(V)

	RDG-50N	RDG-50V
	1,2	1,2
	1-60	30-600
Seat diameter, mm	35 (25)	35(25)
	900 (450)	900 (450)
	±10	±10

	0,3-3	3-30
	1-70	0,03-0,7
D
entrance	50	50
exit	50	50
Construction length L, mm	365	365

length l	440	440
width B	550	550
height H	350	350
Weight, kg, no more	80	80

* Provided with a set of replacement springs.

Design and operating principle of RDG-50N(V)

The regulator actuator (see figure) with control valves and a shut-off valve is designed to automatically maintain a given output pressure in all gas flow modes by changing the flow area of the valve, and to turn off the gas supply in case of emergency increases and decreases in output pressure.

The actuator has a housing 3, inside of which a saddle is installed. The diaphragm actuator consists of a diaphragm 5, a rod connected to it, at the end of which a valve is attached. The rod moves in the bushings of the housing guide column.

Stabilizer 1 is designed to maintain constant pressure at the inlet to the control regulator, i.e., to eliminate the influence of input pressure fluctuations on the operation of the regulator as a whole. The stabilizer is designed as a regulator direct action and includes: housing, spring-loaded diaphragm assembly, operating valve. The inlet pressure gas flows through stabilizer 1 to the control regulator 7. From the control regulator (for the RDG-80N version) or from the stabilizer (for the RDG-80V version), the gas flows through the adjustable throttle 4 into the submembrane cavity, and through the impulse tube into the supra-membrane cavity actuator. Through the throttle, the submembrane cavity of the actuator is connected to the gas pipeline behind the regulator. The pressure in the submembrane cavity of the actuator during operation will always be greater than the output pressure. The supra-membrane cavity of the actuator is under the influence of output pressure.

The control regulator (for the RDG-80N version) or the stabilizer (for the RDG-80V version) maintains a constant pressure, so the pressure in the submembrane cavity will also be constant (in the set mode).

Any deviations of the output pressure from the set one cause changes in the pressure in the above-membrane cavity of the actuator, which leads to the valve moving to a new equilibrium state corresponding to the new values of inlet pressure and flow rate, while the outlet pressure is restored. In the absence of gas flow, the valve is closed, which is determined by the absence of a control pressure difference in the above-membrane cavity of the actuator and the action of the inlet pressure. If there is gas consumption, a control difference is formed in the above-membrane and under-membrane cavities of the actuator, as a result of which the membrane 5 with the rod connected to it, at the end of which the valve is fixed, will move and open the passage of gas through the gap formed between the valve seal and the seat. When the gas flow rate decreases, the valve, under the influence of the control differential pressure in the cavities of the actuator, together with the membrane, will move in reverse side and will reduce the passage of gas, and in the absence of gas flow, the valve will close the seat. In the event of emergency increases and decreases in the output pressure, the membrane of control mechanism 2 moves to the left or right, the shut-off valve rod comes out of contact with the rod 6 of the shut-off valve control mechanism, and under the action of a spring closes the gas inlet into the regulator.

Gas pressure regulator RDG:
1 - stabilizer; 2 — membrane of the control mechanism; 3 - body; 4 - adjustable throttle; 5 - membrane; 6 — rod; 7 - control knob

	RDG-50N	RDG-50V
Maximum inlet pressure, MPa	1,2	1,2
Output pressure setting limits, kPa	1-60	30-600
Seat diameter, mm	35 (25)	35(25)
Capacity at an inlet pressure of 0.1 MPa and an outlet pressure of 0.001 MPa for gas with a density of 0.72 kg/m³, m³/h	900 (450)	900 (450)
Unevenness of regulation, %, no more	±10	±10
Limits for setting the response pressure of the automatic shutdown device, kPa:
when outlet pressure decreases	0,3-3	3-30
when outlet pressure increases	1-70	0,03-0,7
D y, connecting pipe, mm:
entrance	50	50
exit	50	50
Construction length L, mm	365	365
Overall dimensions, mm, no more:
length l	440	440
width B	550	550
height H	350	350
Weight, kg, no more

Technical characteristics of RDG-80-N(V)

	RDG-80-N(V)
Regulated environment	natural gas according to GOST 5542-87
Maximum inlet pressure, MPa	0,1-1,2
Output pressure setting limits, MPa	0,001-0,06(0,06-0,6)
Gas throughput with ρ=0.73 kg/m³, m³/h: R in =0.1 MPa (using N) and R in =0.16 MPa (version B)	2200
Working valve seat diameter, mm:
big	80
small	30
Unevenness of regulation, %	±10
Pressure setting limit of the triggered automatic shutdown device, MPa:
when outlet pressure decreases	0,0003-0,0030...0,01-0,03
when outlet pressure increases	0,003-0,070...0,07-0,7
Connecting dimensions, mm:
D at the inlet pipe	80
D at the outlet pipe	80
Compound	flanged according to GOST 12820
Overall dimensions, mm	575×585×580
Weight, kg	105

Design and operating principle of RDG-80-N(V)

The actuator (see figure) with small 7 and large 8 control valves, shut-off valve 4 and noise suppressor 13 is designed by changing the flow sections of the small and large control valves to automatically maintain a given output pressure in all gas flow modes, including zero, and turn off the gas supply in case of emergency increase or decrease in output pressure. The actuator consists of a cast body 3, inside of which a large seat 5 is installed. The valve seat is replaceable. A diaphragm actuator is attached to the bottom of the housing. The pusher 11 rests on the central seat of the membrane plate 12, and the rod 10 rests on it, transmitting the vertical movement of the membrane plate to the rod 19, at the end of which a small control valve 7 is rigidly fixed. The rod 10 moves in the bushings of the housing guide column. Between the protrusion and the small valve, a large control valve 8 sits freely on the rod, in which the seat of the small valve 7 is located. Both valves are spring-loaded.

Under the large saddle 5 there is a noise suppressor in the form of a glass with slotted holes.

Stabilizer 1 is designed (in the “H” version) to maintain constant pressure at the inlet to the control regulator, i.e., to eliminate the influence of fluctuations in output pressure on the operation of the regulator as a whole. The stabilizer is made in the form of a direct-acting regulator and includes: a body, a membrane assembly, a head, a pusher, a valve with a spring, a seat, a glass and a spring for adjusting the stabilizer to a given pressure before entering the control regulator. The pressure on the pressure gauge after the stabilizer must be at least 0.2 MPa (to ensure stable flow).

Stabilizer 1 (for version “B”) maintains constant pressure behind the regulator by maintaining constant pressure in the sub-membrane cavity of the actuator. The stabilizer is designed as a direct-acting regulator. In the stabilizer, unlike the control regulator, the supra-membrane cavity is not connected to the supra-membrane cavity of the actuator, and a stiffer spring is installed to adjust the regulator. Using the adjusting glass, the regulator is adjusted to the specified output pressure.

The pressure regulator 20 generates control pressure in the submembrane cavity of the actuator in order to reset the control valves of the control system. The control regulator includes the following parts and assemblies: body, head, assembly, membranes; a pusher, a valve with a spring, a seat, a glass and a spring to adjust the regulator to a given output pressure. Using the adjusting glass of the control regulator (for version “N”), the pressure regulator is adjusted to the specified output pressure.

Adjustable chokes 17, 18 from the submembrane cavity of the actuator and on the discharge impulse tube are used to set the regulator to quiet (without fluctuations) operation. The adjustable throttle includes: a body, a slotted needle and a plug.

The pressure gauge is designed to monitor the pressure in front of the control regulator.

The control mechanism 2 of the shut-off valve is designed to continuously monitor the output pressure and issue a signal to activate the shut-off valve in the actuator in the event of an emergency increase or decrease in the output pressure above the permissible set values. The control mechanism consists of a detachable housing, a membrane, a rod, a large and a small spring, which balance the action of the output pressure pulse on the membrane.

Filter 9 is designed to purify the gas supplying the stabilizer from mechanical impurities

The regulator works as follows.

The input pressure gas flows through the filter to the stabilizer 1, then to the control regulator 20 (for version “N”). From the control regulator (for version “H”) or the stabilizer (for version “B”), gas flows through an adjustable throttle 18 into the submembrane cavity and through an adjustable throttle 17 into the submembrane cavity of the actuator. Through the throttle washer 21, the above-membrane cavity of the actuator is connected by a pulse tube 14 to the gas pipeline behind the regulator. Due to the continuous flow of gas through the throttle 18, the pressure in front of it, and therefore the submembrane cavity of the actuator, will always be greater than the output pressure during operation. The supra-membrane cavity of the actuator is under the influence of output pressure. The pressure regulator (for version “H”) or stabilizer (for version “B”) maintains a constant pressure, so the pressure in the submembrane cavity will also be constant (in steady state). Any deviations of the output pressure from the set one cause changes in the pressure in the above-membrane cavity of the actuator, which leads to the movement of the control valve to a new equilibrium state corresponding to the new values of inlet pressure and flow rate, while the outlet pressure is restored. In the absence of gas flow, the small 7 and large 8 control valves are closed, which is determined by the action of the springs 6 and the absence of a control pressure difference in the above-membrane and submembrane cavities of the actuator and the action of the outlet pressure. If there is a minimum gas consumption, a control pressure difference is formed in the above-membrane and under-membrane cavities of the actuator, as a result of which the membrane 12 will begin to move under the action of the resulting lift force. Through the pusher 11 and the rod 10, the movement of the membrane is transmitted to the rod 19, at the end of which the small valve 7 is rigidly fixed, as a result of which the passage of gas opens through the gap formed between the seal of the small valve and the small seat, which is directly installed in the large valve 8. In this case, the valve under the action of spring 6 and inlet pressure it is pressed against the large seat, so the flow rate is determined by the flow area of the small valve. With a further increase in gas flow under the influence of the control differential pressure in the indicated cavities of the actuator, the membrane 12 will begin to move further and the rod with its protrusion will begin to open the large valve and increase the passage of gas through the additionally formed gap between the valve seal 8 and the large seat 5. When the gas flow rate decreases, the large valve 8, under the action of a spring and moving in the opposite direction under the influence of a modified control pressure difference in the cavities of the actuator rod 19 with protrusions, will reduce the flow area of the large valve and subsequently close the large seat 5. The regulator will begin to operate in low load modes.

With a further decrease in gas flow, the small valve 7, under the action of the spring 6 and the changed control pressure difference in the cavities of the actuator, together with the membrane 12, will move further in the opposite direction and reduce the gas flow.

If there is no gas flow, small valve 7 will close the small seat. In the event of an emergency increase and decrease in the output pressure, the membrane of the control mechanism 2 moves left and right, the shut-off valve lever 4 comes out of contact with the rod 16, the shut-off valve, under the action of the spring 15, will shut off the gas flow of the regulator.

1 - stabilizer; 2 - control mechanism; 3 — actuator housing; 4 — shut-off valve; 5 — large saddle; 6 — springs of small and large control valves; 7, 8 — small and large control valve; 9 - filter; 10 — rod of the actuator; 11 — pusher; 12 — membrane of the actuator; 13—silencer; 14 — pulse tube of the output gas pipeline; 15 — shut-off valve spring; 16 — control mechanism rod; 17, 18 — regulating throttles; 19 — rod; 20 — control regulator; 21 — throttle washer

Classification.Gas pressure regulators are classified: according to the purpose, the nature of the regulatory influence, the connections between the input and output quantities, the method of influencing the control valve.

According to the nature of the regulatory effect, regulators are divided into astatic and static (proportional). Schematic diagrams regulators are shown in the figure below.

Pressure regulator diagram

a - astatic: 1 - rod; 2 - membrane; 3 - loads; 4 - submembrane cavity; 5 - gas outlet; 6 - valve; b - static: 1 - rod; 2 - spring; 3 - membrane; 4 - submembrane cavity; 5 - impulse tube; 6 - oil seal; 7 - valve.

IN astatic regulator membrane has a piston shape, and its active area, which perceives gas pressure, practically does not change at any position of the control valve. Therefore, if the gas pressure balances the gravity of the membrane, rod and valve, then the membrane suspension corresponds to a state of astatic (indifferent) equilibrium. The process of regulating gas pressure will proceed as follows. Let us assume that the gas flow through the regulator is equal to its inflow and the valveoccupies a certain position. If the gas flow increases, the pressure will decreaseand the membrane device will lower, which will lead to additional opening of the control valve. After equality between inflow and flow is restored, the gas pressure will increase to a predetermined value. If the gas flow rate decreases and the gas pressure increases accordingly, the control process will proceed in the opposite direction. Adjust the regulator to the required gas pressure using special weights, Moreover, as their mass increases, the gas outlet pressure increases.

Astatic regulators after disturbance lead adjustable pressure to the set value, regardless of the load size and the position of the control valve. Equilibrium of the system is possible only at a given value of the controlled parameter, while the control valve can occupy any position. Astatic regulators are often replaced by proportional ones.

In static (proportional) regulators, unlike astatic ones, the submembrane cavity is separated from the manifold by an oil seal and connected to it by a pulse tube, that is, the nodes feedback located outside the facility. Instead of weights, the compression force of the spring acts on the membrane.

In an astatic regulator, the slightest change in the gas outlet pressure can lead to movement of the control valve from one extreme position to another, and in a static regulator, complete movement of the valve occurs only with appropriate compression of the spring.

Both astatic and proportional regulators, when working with very narrow limits of proportionality, have the properties of systems operating on the “open-closed” principle, that is, with a slight change in the gas parameter, the valve moves instantly. To eliminate this phenomenon, special chokes are installed in the fitting connecting the working cavity of the membrane device with a gas pipeline or spark plug. Installing throttles allows you to reduce the speed of valve movement and achieve more stable operation of the regulator.

According to the method of influencing the control valve, there are direct and direct regulators. indirect action. In regulators direct action the control valve is under the influence of the regulating parameter directly or through dependent parameters and, when the value of the regulated parameter changes, it is actuated by the force arising in sensitive element a regulator sufficient to move the control valve without an external source of energy.

In regulators indirect action the sensing element acts on the control valve with an external source of energy ( compressed air, water or electric current).

When the value of the regulating parameter changes, the force generated in the sensing element of the regulator actuates an auxiliary device that allows energy from an external source to enter the mechanism that moves the control valve.

Direct-acting pressure regulators are less sensitive than indirect-acting regulators. Relatively simple design and high reliability of direct-acting pressure regulators determined their wide application in the gas industry.

Throttling devices pressure regulators (picture below) - valves various designs. Gas pressure regulators use single-seat and double-seat valves. Single-seat valves are subject to a one-way force, equal to the product the area of the seat opening on the pressure difference on both sides of the valve. The presence of forces on only one side complicates the regulation process and at the same time increases the effect of pressure changes upstream of the regulator on the outlet pressure. At the same time, these valves provide reliable shutoff of gas in the absence of gas extraction, which has led to their widespread use in the designs of regulators used in hydraulic fracturing.

Throttle devices for gas pressure regulators

a - rigid single-seat valve; b - soft single-seat valve; c - cylindrical valve with a window for gas passage; d - rigid double-seated continuous valve with guide feathers; d - soft double-seat valve

Double seat valves do not provide a tight seal. This is explained by the uneven wear of the seats, the difficulty of grinding the valve simultaneously to two seats, and also by the fact that with temperature fluctuations the dimensions of the valve and seat change unequally.

The throughput of the regulator depends on the size of the valve and its stroke. Therefore, regulators are selected depending on the maximum possible gas consumption, as well as the size of the valve and its stroke. Regulators installed in the hydraulic fracturing unit must operate in the load range from 0 (“at dead end”) to maximum.

The flow capacity of the regulator depends on the pressure ratio before and after the regulator, gas density and final pressure. In the instructions and reference books there are tables of the capacity of the regulators at a pressure drop of 0.01 MPa. To determine the capacity of the regulators with other parameters, it is necessary to do a recalculation.

Membranes. With the help of membranes, gas pressure energy is converted into mechanical energy of movement, transmitted through a system of levers to the valve. The choice of membrane design depends on the purpose of the pressure regulators. In astatic regulators, constancy work surface The membrane is achieved by giving it a piston shape and using corrugation bend limiters.

Ring diaphragms are most widely used in regulator designs (figure below). Their use made it easier to replace membranes during repair work and made it possible to unify the main measuring devices various types regulators

Annular membrane

a - with one disk: 1 - disk; 2 - corrugation; b - with two disks

The upward and downward movement of the membrane device occurs due to the deformation of the flat corrugation formed by the support disk. If the membrane is in its lowest position, then the active area of the membrane is its entire surface. If the membrane moves to its highest position, its active area is reduced to the area of the disk. As the disk diameter decreases, the difference between the maximum and minimum active area will increase. Therefore, to lift the annular membranes, a gradual increase in pressure is necessary to compensate for the decrease in the active area of the membrane. If the membrane is subjected to alternating pressure on both sides during operation, install two disks - on top and bottom.

For low outlet pressure regulators, the one-way gas pressure on the membrane is balanced by springs or weights. With high or medium outlet pressure regulators, gas is supplied to both sides of the membrane, relieving it from unilateral forces.

Direct acting regulators are divided into pilot and unmanned. Pilot regulators(RSD, RDUK and RDV) have a control device in the form of a small regulator called a pilot.

Unmanned regulators(RD, RDK and RDG) do not have a control device and differ from the pilot ones in dimensions and throughput.

Direct acting gas pressure regulators. Regulators RD-32M and RD-50M are unmanned, direct-acting, differ in nominal diameter of 32 and 50 mm and provide gas supply up to 200 and 750 m 3 /h, respectively. The housing of the RD-32M regulator (figure below) is connected to the gas pipeline with union nuts. The reduced gas is supplied through the impulse tube into the sub-membrane space of the regulator and exerts pressure on the elastic membrane. A spring exerts back pressure on top of the membrane. If the gas flow rate increases, its pressure behind the regulator will decrease, and the gas pressure in the sub-membrane space of the regulator will correspondingly decrease, the equilibrium of the membrane will be disrupted, and it will move downward under the action of the spring. Due to the downward movement of the diaphragm, the lever mechanism will move the piston away from the valve. The distance between the valve and the piston will increase, this will lead to an increase in gas flow and restoration of the final pressure. If the gas flow behind the regulator decreases, the outlet pressure will increase and the regulation process will occur in the opposite direction. Replaceable valves allow you to change the flow capacity of the regulators. The regulators are adjusted to a given pressure mode using an adjustable spring, nut and adjusting screw.

Pressure regulator RD-32M

1 - membrane; 2 - adjustable spring; 3.5 - nuts; 4 - adjusting screw; 6 - plug; 7 - nipple; 8, 12 - valves; 9 - piston; 10 - final pressure impulse tube; 11 - lever mechanism; 12 - safety valve

During hours of minimum gas consumption, the gas outlet pressure may increase and cause the regulator membrane to rupture. A special device, a safety valve, built into the central part of the membrane protects the membrane from rupture. The valve ensures the release of gas from the submembrane space into the atmosphere.

Combined regulators. The domestic industry produces several varieties of such regulators: RDNK-400, RDGD-20, RDSC-50, RGD-80. These regulators received this name because relief and shut-off (shut-off) valves are installed in the regulator body. The figures below show circuits of combined regulators.

Regulator RDNK-400. Regulators of the RDNK type are produced in modifications RDNK-400, RDNK-400M, RDNK-1000 and RDNK-U.

Gas pressure regulator RDNK-400

1 - relief valve; 2, 20 - nuts; 3 - adjustment spring relief valve; 4 - working membrane; 5 - fitting; 6 - outlet pressure adjustment spring; 7 - adjusting screw; 8 - membrane chamber; 9, 16 - springs; 10 - working valve; 11, 13 - pulse tubes; 12 - nozzle; 14 - disconnecting device; 15 - glass; 17 - shut-off valve; 18 - filter; 19 - body; 21, 22 - lever mechanism

The design and principle of operation of the regulators is shown using the example of RDNK-400 (figure above). A low outlet pressure regulator consists of a pressure regulator itself and an automatic shut-off device. The regulator has a built-in impulse tube entering the submembrane cavity and an impulse tube. The nozzle located in the regulator body is both a seat for the working and shut-off valves. The working valve is connected to the working diaphragm through a lever mechanism (rod and lever). A replaceable spring and adjusting screw are designed to adjust the gas outlet pressure.

The shut-off device has a membrane connected to an actuator, the latch of which holds the shut-off valve in open position. The switching device is adjusted using replaceable springs located in the glass.

Gas medium or high pressure supplied to the regulator, passes through the gap between the working valve and the seat, and is reduced to low pressure and goes to consumers. The pulse from the output pressure through the pipeline comes from the output pipeline into the sub-membrane cavity of the regulator and to the shutdown device. When the outlet pressure increases or decreases above the specified parameters, the latch located in the shut-off device is disengaged by force on the membrane of the shut-off device, the valve closes the nozzle, and the flow of gas stops. The regulator is put into operation manually after eliminating the reasons that caused the tripping device. Specifications regulator are shown in the table below.

Technical characteristics of the RDNK-400 regulator

The manufacturer supplies the regulator set to an outlet pressure of 2 kPa, with the relief and shut-off valves adjusted accordingly. The output pressure is adjusted by rotating the screw. When rotating clockwise, the output pressure increases, counter-clockwise, it decreases. The relief valve is adjusted by rotating the nut, which loosens or compresses the spring.

Regulator RDSC-50.A regulator with an output medium pressure contains an independently operating pressure regulator, an automatic shut-off device, a relief valve, and a filter (figure below). The technical characteristics of the regulator are given in the table below.

Gas pressure regulator RDSC-50

1 - shut-off valve; 2 - valve seat; 3 - body; 4, 20 - membrane; 5 - cover; 6 - nut; 7 - fitting; 8, 12, 21, 22, 25, 30 - springs; 9, 23, 24 - guides; 10 - glass; 11, 15, 26, 28 - rods; 13 - relief valve; 14 - unloading membrane; 16 - working valve seat; 17 - working valve; 18, 29 - impulse tubes; 19 - pusher; 27 - plug; 31 - regulator body; 32 - mesh filter

The output pressure is adjusted by rotating the guide. When rotating clockwise, the output pressure increases, counter-clockwise, it decreases. The response pressure of the relief valve is adjusted by rotating the nut.

The shut-off device is adjusted by lowering the output pressure by compressing or weakening the spring, rotating the guide, and also increasing the output pressure by compressing or weakening the spring, rotating the guide.

Starting the regulator after eliminating the malfunctions that caused the tripping device is performed by unscrewing the plug, as a result of which the valve moves down until the rod, under the action of the spring, moves to the left and retracts behind the protrusion of the valve stem, thus holding it in the open position. After this, the plug is screwed in until it stops.

Regulator specifications RDSC-50

Maximum inlet pressure, MPa, no more
Output pressure setting limits, MPa
Throughput at inlet pressure 0.3 MPa, m 3 / h, no more
Fluctuation of output pressure without adjusting the regulator when gas flow changes and fluctuations in inlet pressure by ±25%, MPa, no more
Upper limit of the pressure setting for the start of operation of the relief valve, MPa
Upper and lower limits for setting the response pressure of the automatic shutdown device, MPa: when the output pressure increases, more, when the output pressure decreases, less
Nominal diameter, mm: inlet pipe outlet pipe

The manufacturer supplies the regulator set to an outlet pressure of 0.05 MPa, with the corresponding setting of the relief valve and shut-off device. When adjusting the outlet pressure of the regulator, as well as activating the relief valve and shut-off device, use the replaceable springs included in the delivery kit. The regulator is installed on a horizontal section of the gas pipeline with the glass facing up.

Gas pressure regulator RDG-80(picture below). Combined regulators of the RDG series for regional hydraulic fracturing are produced at conditional passages 50, 80, 100, 150 mm; they do not have a number of disadvantages inherent in other regulators.

Regulator RDG-80

1 - pressure regulator; 2 - pressure stabilizer; 3 - inlet tap; 4 - shut-off valve; 5 - working large valve; 6 - spring; 7 - working small valve; 8 - pressure gauge; 9 - impulse gas pipeline; 10 - rotary axis of the shut-off valve; 11 - rotary lever; 12 - shut-off valve control mechanism; 13 - adjustable throttle; 14 - noise suppressor

Each type of regulator is designed to reduce high or medium gas pressure to medium or low, automatic maintenance output pressure at a given level, regardless of changes in flow rate and inlet pressure, as well as to automatically shut off the gas supply in the event of an emergency increase or decrease in output pressure above the specified permissible values.

The scope of application of RDG regulators is hydraulic fracturing and gas reduction units for industrial, municipal and domestic facilities. Regulators of this type are indirect acting. The regulator includes: an actuator, a stabilizer, and a control regulator (pilot).

The RDG-80 regulator provides stable and accurate regulation of gas pressure from minimum to maximum. This is achieved by the fact that the control valve of the actuator is made in the form of two spring-loaded valves different diameters, ensuring stability of regulation over the entire range of flow rates, and in the control regulator (pilot) the working valve is located on a double-armed lever, the opposite end of which is spring-loaded; the setting force on the lever is applied between the lever support and the spring. This ensures the tightness of the working valve and the accuracy of regulation in proportion to the ratio of the lever arms.

The actuator consists of a housing, inside of which a large saddle is installed. The diaphragm actuator includes a diaphragm of a rod rigidly connected to it, at the end of which a small valve is fixed; A large valve is located freely between the protrusion of the rod and the small valve, and the seat of the small valve is also attached to the rod. Both valves are spring loaded. The rod moves in the bushings of the housing guide column. Under the saddle there is a noise suppressor made in the form of a pipe with slotted holes.

The stabilizer is designed to maintain constant pressure at the inlet to the control regulator, that is, to eliminate the influence of fluctuations in inlet pressure on the operation of the regulator as a whole.

The stabilizer is made in the form of a direct-acting regulator and includes a housing, a membrane assembly with a spring load, and a working valve, which is located on a double-armed lever, the opposite end of which is spring-loaded. With this design, the control regulator valve is sealed and the outlet pressure is stabilized.

The control regulator (pilot) changes the control pressure in the above-membrane cavity of the actuator in order to rearrange the control valves of the actuator in the event of mismatch of the control system.

The supra-valve cavity of the impulse tube control regulator is connected through throttling devices to the sub-membrane cavity of the actuator and to the discharge gas pipeline.

The submembrane cavity is connected by a pulse tube to the supra-membrane cavity of the actuator. Using the control regulator diaphragm spring adjusting screw, the control valve is adjusted to the specified output pressure.

Adjustable throttles from the submembrane cavity of the actuator and on the discharge impulse tube are used to adjust the regulator for quiet operation. The adjustable throttle includes a body, a needle with a slot and a plug. A pressure gauge is used to control the pressure after the stabilizer.

The control mechanism consists of a detachable housing, a membrane, a rod of large and small springs, equalizing the effect of the output pressure pulse on the membrane.

The shut-off valve control mechanism provides continuous monitoring of the output pressure and issues a signal to activate the shut-off valve in the actuator in the event of an emergency increase or decrease in the output pressure above the specified permissible values.

The bypass valve is designed to balance the pressure in the chambers of the inlet pipe before and after the shut-off valve when it is put into operation.

The regulator works as follows. To put the regulator into operation, it is necessary to open the bypass valve; the inlet gas pressure flows through the impulse tube into the over-valve space of the actuator. The gas pressure before and after the shut-off valve is equalized. Turning the lever opens the shut-off valve. Gas pressure enters the over-valve space of the actuator through the shut-off valve seat and through the pulse gas pipeline into the sub-valve space of the stabilizer. Under the action of the spring and gas pressure, the valves of the actuator are closed.

The stabilizer spring is adjusted to the specified output gas pressure. The inlet gas pressure is reduced to a predetermined value, enters the above-valve space of the stabilizer, into the sub-membrane space of the stabilizer and through the impulse tube into the sub-valve space of the pressure regulator (pilot). The pilot's compressive adjustment spring acts on the diaphragm, the diaphragm moves down, and through the plate acts on the rod, which moves the rocker arm. The pilot valve opens. From the control regulator (pilot), gas flows through an adjustable throttle into the submembrane cavity of the actuator. Through the throttle, the submembrane cavity of the actuator is connected to the cavity of the gas pipeline behind the regulator. The gas pressure in the sub-membrane cavity of the actuator is greater than in the above-membrane cavity. A membrane with a rod rigidly connected to it, at the end of which a small valve is attached, will move and open the passage of gas through the gap formed between the control of the small valve and the small seat, which is directly installed in the large valve. In this case, the large valve, under the action of a spring and inlet pressure, is pressed against the large seat, and therefore the gas flow is determined by the flow area of the small valve.

Gas outlet pressure impulse lines(without throttles) enters the sub-membrane space of the pressure regulator (pilot), into the above-membrane space of the actuator and onto the membrane of the shut-off valve control mechanism.

When the gas flow rate increases under the influence of the control differential pressure in the cavities of the actuator, the membrane will begin to move further and the rod with its protrusion will begin to open the large valve and increase the passage of gas through the additionally formed gap between the seal of the large valve and the large seat.

When the gas flow rate decreases, the large valve, under the action of a spring and moving in the opposite direction under the influence of a modified control differential pressure in the cavities of the actuator rod with protrusions, will reduce the flow area of the large valve and close the large seat; in this case, the small valve remains open, and the regulator will begin to operate in low load mode. With a further decrease in gas flow, the small valve, under the action of the spring and the control differential pressure in the cavities of the actuator, together with the membrane, will move further in the opposite direction and reduce the gas passage, and in the absence of gas flow, the small valve will close the seat.

In the event of emergency increases or decreases in the output pressure, the membrane of the control mechanism moves to the left or right, the shut-off valve rod comes out of contact with the rod of the control mechanism, and the valve, under the action of a spring, closes the gas inlet into the regulator.

Gas pressure regulator designed by Kazantsev (RDUK). The domestic industry produces these regulators with conditional passage 50, 100 and 200 mm. The characteristics of the RDUK are shown in the table below.

Characteristics of RDUK regulators

Throughput at a pressure drop of 10,000 Pa and a density of 1 kg/m, m 3 /h	Diameter, mm	Pressure, MPa
	conditional	maximum input	final

Regulator RDUK-2

a - sectional view of the regulator; b - regulator pilot; c - regulator wiring diagram; 1, 3, 12, 13, 14 - impulse tubes; 2 - control regulator (pilot); 3 - body; 5 - valve; 6 - column; 7 - valve stem; 8 - membrane; 9 - support; 10 - throttle; 11 - fitting; 15 - fitting with a pusher; 16, 23 - springs; 17 - plug; 18 - pilot valve seat; 19 - nut; 20 - housing cover; 21 - pilot body; 22 - threaded glass; 24 - disk

The RDUK-2 regulator (see figure above) consists of the following elements: a control valve with a diaphragm drive (actuator); control regulator (pilot); chokes and connecting tubes. The initial pressure gas passes through a filter before entering the control regulator, which improves the pilot's working conditions.

The pressure regulator membrane is sandwiched between the housing and the lid of the membrane box, and in the center - between a flat and cup-shaped disk. The cup-shaped disk rests against the groove in the lid, which ensures that the membrane is centered before it is clamped.

A pusher rests in the middle of the membrane plate seat, and a rod presses on it, which moves freely in the column . The valve spool is freely hung on the upper end of the rod. Tight closure of the valve seat is ensured by the mass of the spool and the gas pressure on it.

The gas leaving the pilot flows through the impulse tube under the regulator membrane and is partially discharged through the tube into the outlet gas pipeline. To limit this discharge, a throttle with a diameter of 2 mm is installed at the junction of the tube with the gas pipeline, thereby achieving the required gas pressure under the regulator membrane with insignificant gas flow through the pilot. The impulse tube connects the above-membrane cavity of the regulator with the outlet gas pipeline. The above-membrane cavity of the pilot, separated from its outlet fitting, also communicates with the outlet gas pipeline through an impulse tube. If the gas pressure on both sides of the regulator diaphragm is the same, then the regulator valve is closed. The valve can only be opened if the gas pressure below the membrane is sufficient to overcome the gas pressure on the valve from above and overcome the gravity of the membrane suspension.

The regulator works as follows. Initial pressure gas from the regulator's over-valve chamber enters the pilot. After passing the pilot valve, the gas moves through the impulse tube, passes through the throttle and enters the gas pipeline after the control valve.

The pilot valve, throttle and impulse tubes are a throttle type booster device.

The final pressure pulse perceived by the pilot is amplified by the throttle device, transformed into command pressure and transmitted through the tube to the sub-membrane space of the actuator, moving the control valve.

As gas flow decreases, the pressure after the regulator begins to increase. This is transmitted through an impulse tube to the pilot diaphragm, which moves down, closing the pilot valve. In this case, the gas from the high side of the impulse tube cannot pass through the pilot. Therefore, its pressure under the regulator membrane gradually decreases. When the pressure under the membrane is less than the force of gravity of the plate and the pressure exerted by the regulator valve, as well as the gas pressure on the valve from above, the membrane will go down, displacing gas from under the membrane cavity through the impulse tube for release. The valve gradually begins to close, reducing the opening for gas passage. The pressure after the regulator will drop to the set value.

As gas flow increases, the pressure after the regulator decreases. The pressure is transmitted through the impulse tube to the pilot membrane. The pilot diaphragm moves upward under the action of a spring, opening the pilot valve. Gas from the high side flows through the impulse tube to the pilot valve and then through the impulse tube goes under the regulator diaphragm. Part of the gas is discharged through the impulse tube, and part - under the membrane. The gas pressure under the regulator membrane increases and, overcoming the mass of the membrane suspension and the gas pressure on the valve, moves the membrane upward. The regulator valve opens, increasing the opening for gas passage. The gas pressure after the regulator increases to the specified value.

When the gas pressure in front of the regulator increases, it reacts in the same way as in the first case considered. When the gas pressure in front of the regulator decreases, it operates in the same way as in the second case.

Technical characteristics of RDG-50-N(V)

	RDG-50-N(V)
Regulated environment	natural gas according to GOST 5542-87
Maximum inlet pressure, MPa	0,1-1,2
Output pressure setting limits, MPa	0,001-0,06(0,06-0,6)
Gas throughput with ρ=0.73 kg/m³, m³/h: R in =0.1 MPa (using N) and R in =0.16 MPa (version B)	1300
Working valve seat diameter, mm:
big	50
small	20
Unevenness of regulation, %	±10
Pressure setting limit of the triggered automatic shutdown device, MPa:
when outlet pressure decreases	0,0003-0,0030...0,01-0,03
when outlet pressure increases	0,003-0,070...0,07-0,7
Connecting dimensions, mm:
D at the inlet pipe	50
D at the outlet pipe	50
Compound	flanged according to GOST 12820
Overall dimensions, mm	435×480×490
Weight, kg	65

Design and operating principle of RDG-50-N(V)

Under the large saddle 5 there is a noise suppressor in the form of a glass with slotted holes.

The pressure gauge is designed to monitor the pressure in front of the control regulator.

Filter 9 is designed to purify the gas supplying the stabilizer from mechanical impurities

The regulator works as follows.

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