1、 Overview

Self operated pressure regulating valve is an actuator product that does not require any external energy and utilizes the energy of the regulated medium to achieve automatic regulation.

The feature of this product is that it can work in places without electricity or gas, while saving energy. The pressure setting value can be adjusted freely during operation. With quick opening flow characteristics, sensitive action and good sealing performance, it is widely used in the automatic control of gas, liquid and steam medium pressure reduction and stabilization (used for post valve regulation), or pressure relief and stabilization (used for pre valve regulation) in various industrial equipment such as petroleum, chemical industry, electric power, metallurgy, food, light textile, machinery manufacturing and residential buildings.

The pressure regulating valve mainly consists of four parts: the detection actuator, the pressure regulating valve, the condenser, and the isosceles triangle connecting pipe behind the valve. Its structure (see Figure 1).

Figure 1a shows a pressure regulating valve used to control the pressure behind the valve, which operates in a pressure closed manner. The principle is as follows: the medium flows into the valve body in the direction of the arrow, passes through the valve core and valve seat, and is then output after throttling. After being cooled by a condenser (used when the medium is steam), the other route is introduced into the actuator to act on the diaphragm, causing the valve core to undergo corresponding displacement, achieving the purpose of pressure reduction and stabilization. If the pressure behind the valve increases, the force acting on the diaphragm increases, compressing the spring and driving the valve core, reducing the valve opening until the pressure behind the valve drops to the set value. Similarly, if the pressure behind the valve decreases, the force acting on the diaphragm decreases. Due to the reaction force of the spring, the valve core is driven, causing the valve opening degree to increase until the pressure behind the valve rises to the set value.

Figure 1b: A pressure regulating valve used to control the pressure in front of the valve, which operates in a pressure open type. The principle is as follows: the medium flows into the valve body in the direction of the arrow, and after being cooled by the condenser (used when the medium is steam), it is introduced into the actuator to act on the diaphragm, causing the valve core to undergo corresponding displacement, achieving the purpose of pressure relief and stabilization. As the pressure in front of the valve increases, the force acting on the diaphragm also increases, compressing the spring and driving the core to increase the valve opening until the pressure in front of the valve drops to the set value. Similarly, if the valve opening decreases until the pressure in front of the valve rises to the set value.

4、 Main technical parameters and performance indicators, materials

1Main technical parameters and performance indicators

Nominal diameter DN (mm)		20	25	32	40	50	65	80	100	125	150	200	250	300
Rated flow coefficient (KV)		7	11	20	30	48	75	120	190	300	480	760	1100	1750
Rated stroke (mm)		8		10		14	20		25	40		50	60	70
Nominal pressure PN (Mpa)		1.6, 4.0, 6.4
Pressure regulation range (Kpa)		15-50, 40-80, 60-100, 80-140, 120-180, 160-220, 200-260 240-300, 280-350, 330-400, 380-450, 430-500, 480-560, 540-620 600-700, 680-800, 780-900, 880-1000, 600-1500, 1000-2500
Traffic characteristics		Quick open
Adjustment accuracy (%)		±5
Operating temperature (℃)		≤350
allow leakage rate	Hard seal (l/h)	Single seat: ≤ 10-4? Rated capacity of valve (Class IV); Double seat, sleeve ≤ 5 × 10-3?? Rated capacity of valve (Class II)
	Soft seal (ml/h)	0.15		0.30		0.45	0.60	0.90	1.7	4.0		6.75	11.10	11.60
Pressure reducing ratio	maximum	10
	minimum	1.25

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2Determination of pressure regulation range

The pressure regulation range is segmented, as shown in the main parameters and performance indicators table. The control pressure should be selected as close as possible to the middle value of the regulation range (see Table 1).

What is the range of pressure regulation (for example, for thin film actuators, 1000-2500KPa depending on specific operating conditions)??

Pressure regulation range (Kpa)	Pressure segmentation range (Kpa)	Effective area of membrane chamber (cm2)	Valve diameter used (mm)
15~140	40~80	280	20~25
	60~140
	15~50	400	32~300
	40~80
	60~140
120~300	120~300	70	20~50
		100	65~100
		280	125~300
280~500	280~500	200	20~300
480~1000	480~1000	70	20~50
		100	65~100
		280	125~300

3. The relationship between the pre valve pressure and the post valve pressure of a pressure regulating valve

The self regulating valve itself is a regulating system, and the valve itself has certain pressure drop requirements. For the pressure regulating valve (type B) after the valve, in order to ensure that the pressure after the valve is within a certain range, the pressure before the valve must reach a certain value. The requirements can be seen in the following table:?

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upstream pressure	downstream pressure	upstream pressure	downstream pressure	upstream pressure	downstream pressure	upstream pressure	downstream pressure
30	15~24	350	35~280	700	70~560	1250	125~1000
50	15~40	400	40~320	750	75~600	1500	150~1200
100	15~80	450	45~360	800	80~640	2000	200~1600
150	15~120	500	50~400	850	85~680	2500	250~2000
200	20~160	550	55~440	900	90~720	3000	300~2400
250	25~200	600	60~480	950	95~760
300	30~240	650	65~520	1000	100~800

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4. Dimensions and weight(Unit:mm)

Nominal diameter DN			20	25	32	40	50	65	80	100	125	150	200	250	300
Flange connection size B			383		512		603	862		1023	1380		1800	2000	2200
Flange end distance L			150	160	180	200	230	290	310	350	400	480	600	730	850
Pressure regulation range Kpa	15-140	H	475		520		540	710		780	840	880	915	940	1000
		A	280		308
	130-300	H	455		500		520	690		760	800	870	880	900	950
		A	230
	280-500	H	450		490		510	680		750	790	860	870	890	940
		A	176					194			280
	480-1000	H	445		480			670		740	780	850	860	880	930
		A	176					194			280
	600-1500	H	445		570		600	820		890	950		1000	1100	1200
		A	85		96
	1000-2500	H	445		570		600	820		890	950		1000	1100	1200
		A	85		96
Weight Kg			26		37		42	72	90	114	130	144	180	200	250
Thread of pressure pipe joint			M16×1.5

?5Main component materials????????????????????????????????

Part name	material
Valve?? body	ZG230-450、ZG1Cr18Ni9Ti、ZGCr18Ni12Mo2Ti
Valve?? rush pith	1Cr18Ni9Ti、Cr18Ni12Mo2Ti
Valve?? seat	1Cr18Ni9Ti、Cr18Ni12Mo2Ti
Valve?? pole	1Cr18Ni9Ti、Cr18Ni12Mo2Ti
rubber diaphragm	Ding Qing, Yi Bing, fluorine, oil resistant rubber
The membrane?? cover	A3 and A4 steel coated with tetrafluoroethylene
Fill it out?? material	Polytetrafluoroethylene, flexible graphite

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Executing Agency:

Valve body working temperature and allowable pressure:

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5、 Installation, use and maintenance

Installation Instructions

P1: Adjust gas, pre valve pressure regulation (K-type), filter (1) can be installed without installation

P2: Adjust the gas, adjust the pressure behind the valve (Type B), and the filter (1) can be left uninstalled

P3: Regulate the liquid and adjust the pressure before the valve (K-type). For non clean fluids, a filter (1) should be installed

P4: Adjust the liquid and adjust the pressure after the valve (Type B). For non clean fluids, a filter (1) should be installed

P5: Adjust the steam and pressure before the valve (K-type), a condenser (4) should be installed, and it is recommended to install a filter (1)

P6: Adjust the steam and adjust the pressure after the valve (Type B). A condenser (4) should be installed, and it is recommended to install a filter (1)

Attention: During installation, the pressure point should be kept at an appropriate distance from the pressure regulating valve. The pressure in front of the control valve should be greater than 2 times the diameter of the pipeline, and the pressure behind the control valve should be greater than 6 times the diameter of the pipeline. When installing the condenser, attention should be paid to its position, making it higher than the membrane head and lower than the process pipeline, to ensure that the condenser is filled with condensate.

6、 When installing, pay attention to the following points:

1. Installation

（1）? The condenser must be higher than the actuator of the pressure regulating valve and lower than the connecting pipe behind the valve (pressure regulating valve behind the valve) or in front of the valve (pressure regulating valve before the valve) to ensure that the condenser is full of condensate.

（2）? The pressure tapping point shall be at a proper position away from the pressure regulating valve. The top note valve shall be more than 2 times the pipe diameter, and the base note pressure regulating valve shall be more than 6 times the pipe diameter.

（3）? For the convenience of on-site maintenance and operation, there should be appropriate space around the pressure regulating valve, and stop valves and bypass manual valves should be installed before and after the valve, as shown in Figure 5.

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Figure 5?? Installation plan for pressure regulating valve group

Note: The dashed line in the figure represents another allowable direction for the inlet and outlet of the pipeline

（4）? When the diameter of the pressure regulating valve is too large (DN ≥ 100), a fixed bracket should be provided.

（5）? The direction of medium flow should be consistent with the arrow on the valve body, and the center of the front and rear pipelines should be aligned with the center of the two flanges of the pressure regulating valve to avoid excessive stress on the valve body.

（6）? A filter should be installed in front of the valve to prevent impurities from clogging the medium.

2（7）? The regulating valve should be installed in environments where the ambient temperature does not exceed -25 ℃~55 ℃.

, Use

Operating procedures for using gases or low viscosity liquids at room temperature: (see Figure 3)

（1）? Slowly open the front and rear shut-off valves of the valve.

（2）? Loosen the exhaust plug until gas or liquid overflows from the actuator.

（3）? Then tighten the exhaust plug again, and the pressure regulating valve can work. The required pressure value can be obtained by adjusting the pressure regulating disc. When adjusting, pay attention to the pressure indication value, and the action should be slow, without causing the valve stem to rotate along with it

? ? ? ? ? Move. Operating procedures when using steam: (see Figure 4)

（1）? Unscrew the drain screw from the condenser.

（2）? Twist the exhaust plug of the actuator.

（3）? Use a drain to add water through the injection port until the exhaust hole flows out.

（4）? Tighten the exhaust plug and continue to inject water until it overflows the injection port.

（5）? Tighten the injection port screw.

（6）? Slowly open the front and rear shut-off valves of the pressure regulating valve.

3（7）? Adjust the pressure regulating disc and observe the pressure reading until it reaches the required level.

Maintenance

After the regulating valve is put into operation, the maintenance workload is generally very small. Usually, it is only necessary to observe whether the pressure readings before and after the valve meet the required process values. In addition, observe whether there is leakage in the stuffing box and actuator. If there is leakage, tighten or replace the stuffing box and diaphragm. Common troubleshooting methods for pressure regulating valves (see Table 5)

Table 5	Fault phenomenon	cause
Troubleshooting The pressure behind the valve is unstable	Changes due to pressure fluctuations in front of the valve 1. The valve core is stuck by foreign objects 2. The valve stem and push rod are stuck	3. Blockage of inlet pipeline 1. Reinstall and remove to eliminate foreign objects 2. Readjust
3. Clearing up The pressure behind the valve cannot be reduced, starting	Eventually changing above the demand value 1. Setting the spring stiffness too high 2. The valve diameter is too large	3. The pressure in front of the valve is too high, and the pressure reduction ratio is too large 1. Replace the spring 2. Replace with a smaller caliber
3. Pre valve pressure: If the post valve pressure exceeds 10:1, it should be reduced in two stages The pressure behind the valve cannot rise, starting	Eventually changing below the demand value 1. Setting the spring stiffness too low 2. The valve diameter is too small	3. The pressure reduction ratio is too small 1. Replace the spring 2. Change the caliber of the trap
3. Valve front pressure: If the valve rear pressure is lower than 1.25, the valve front pressure should be increased The pressure in front of the valve cannot rise, starting	Finally act below the demand value 1. Setting the spring stiffness too low 2. The valve core is stuck by foreign objects 3. The valve stem and push rod are stuck 4. Damaged valve core and seat, excessive leakage	5. The valve diameter is too large 1. Replace the spring 2. Disassemble and reassemble 3. Readjust 4. Grind or replace again
5. Replace with a smaller caliber The pressure in front of the valve cannot be reduced, starting	Act above the demand value at the end 1. Setting the spring stiffness too high 2. The caliber is too small	3. Valve core, valve stem, push rod, etc. are stuck 1. Replace the spring 2. Replace with a larger caliber
3. Eliminate the cause of the blockage and readjust Valve back pressure or valve front pressure	Frequent fluctuations 1. The valve diameter is too large	2. The capacity of the actuator membrane chamber is too small 1. Choose the appropriate valve diameter

2. Install dampers in the inlet pipeline

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7、 Ordering Notice

Please provide the following information when placing an order:	model
name	Nominal Diameter
nominal pressure	Signal Range
action	Medium parameters
Working temperature of the medium	rated flow coefficient
Inherent flow characteristics	Maximum pressure before valve, minimum pressure before valve, normal pressure before valve
Maximum pressure after valve, minimum pressure after valve, normal pressure after valve	Maximum flow, minimum flow, normal flow
Liquid viscosity, liquid density, gas density	Material: valve core, valve body, internal valve components, packing
attachment	Process pipeline size
Special requirements such as corrosion resistance