Air Set Pneumatic Single Seat Control Valve
Air Set Pneumatic Single Seat Control Valve
Air Set Pneumatic Single Seat Control Valve
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Product Introduction
ZJHP pneumatic flow control valve is a small pneumatic single seat control valve, comprehensive development of advanced technology at home and abroad. The valve body is single seat valve, double seat, sleeve seat.
And it is the development direction of today's control valve.
ZJHP pneumatic flow control valve is composed of multi - spring pneumatic diaphragm actuator and top - guided through away low flow resistance single - seat valve. It has the advantages of compact structure, light weight, sensitive action, S-streamline fluid channel, small pressure drop loss, large valve capacity, accurate flow characteristics. It is equipped with electric-air positioner or pneumatic positioner which can realize the automatic regulation and control of the process. The valve is widely used in the precise control of gas, liquid, steam in pressure, flow, temperature, liquid level and other parameters to maintain a given value. If there is no air source at the site, electric actuator could be replaced.
Technical Parameters
Body type
Straight type casting body
Nominal diameter
DN20~300mm
Nominal pressure
PN 1.6, 2.5, 4.0, 6.4, 10.0 MPa
Flange standard
GB/T, JB/T79, HG
Connection type
Flange(FF, RF, RTJ), Welding(SW, BW), Screw(suitable in 1")
Bonnet type
High temperature type +250~+450ºC, Ultra high temperature type+250~+560ºC
Gland type
Bolted compression type
Packing
V type PTFE, containing impregnated PTFE asbestos, asbestos textile, graphite
Main parameter
Power supply voltage: 220V/50Hz, input signal: 4-20mA or 1-5V·DC, output signal: 4-20mA·DC
Protection grade: IP55, flameproof mark: EXDIIBT4, hand function: handle
Ambient temperature: -25 ~ +70ºC, ambient humidity: &#;95%
Base Material
Valve body, bonnet
HT200, ZG230-450 ZG1Cr18Ni9Ti
Valve disc, seat
1Cr18Ni9Ti, surfacing of Stellite alloy
Soft seal disc
reinforced polytetrafluoroethylene
Packing
PTFE, flexible graphite
Corrugated tube
1Cr18Ni9Ti
Gasket
rubber asbestos board, 10, 1Cr18Ni9Ti, asbestos spiral wound gasket
Diaphragm cover
A3
Corrugated diaphragm
nitrile rubber clip reinforced polyester fabric
Spring
60Si2Mn
Stem, push rod
2Cr13, 1Cr18Ni9Ti
Bushing
2Cr13
Feature
1. ZJHP pneumatic flow control valve is the implementation unit of the instrument in the automatic control system with electric-gas valve positioner driven by electric signals and compressed air. It accepts the input 0-10mA DC or 4-20mA DC current signal and the compressed air will be converted into air source pressure signal input and output by the regulator. It can realize the division control (segment amplitude signal) to change the valve opening and achieve the precise control of the process parameters.
2. ZJHP pneumatic flow control valve can be divided by direct action and reverse action according to the mode of action. Direct action: Air to closed-Failed to open, when the pressure signal increases, the valve closed. Reverse action: Air to open-Failed to closed, when the pressure signal increases, the valve open.
3. ZJHP pneumatic flow control valve is straight single seat casting valve with single plunger type disc, especially suitable for small leakage and small pressure difference.
4. The control valve is straight through with low flow resistance, top guide and no bottom bonnet. The valve is composed of seat and plug type disc. It has a good sealing, small leakage, quick action, s-shaped streamlined, small pressure drop loss, large capacity, precise flow characteristic, large adjust rang. The guide area of disc is large to strong ant-vibration. It is applicable to strict requirements of the medium leakage and regulation accuracy. Due to the valve structure, the unbalance force on the stem is larger in the big nominal diameter. So the valve is only suitable for the small pressure difference.
5. Different spool shapes will get different flow characteristics such as percentage (logarithmic), linear, quick opening.
6. The valve spool can be designed and made into according to the requirements of working conditions. And the soft sealing structure is suitable for -20~+120ºC temperature requires strict tightness of acid and alkali, gas.
Actuator
Actuator
ZHA/B Multi-spring diaphragm actuator
Model
ZHA/B-22
ZHA/B-23
ZHA/B-34
ZHA/B-45
ZHA/B-56
Effective area(cm2)
350
350
560
900
Stroke(mm)
10,16
24
40
40,60
100
Spring range(KPa)
20~10, 20-60, 60-100, 40-200, 80-240
Diaphragm material
Nitrile rubber and nylon cloth, ethylene propylene rubber and nylon cloth
Air supply
140~400KPa
Air connetction
RC1/4"
Ambient temperature
-30~+70ºC
Accessories
Positioner, air filter pressure reducer, position valve, travel switch, valve position transmitter, handwheel mechanism, etc.
Acting
Air close(B)-fail to close(FO), air open(K)-fail to close(FC)
Technical parameters
DN (mm )
(dn)
20
25
32
40
50
65
80
100
125
150
200
(10)
(12)
(15)
(20)
Kv
Liner
1.8
2.8
4.4
6.9
11
17.6
27.5
44
69
110
176
275
440
690
Percentage
1.6
2.5
4.0
6.3
10
16
25
40
63
100
160
250
400
630
Rated stroke L (mm)
16
25
40
60
Diaphragm effective area Ae (cm
2
)
280
400
600
Signal range Pr (kPa)
20 ~ 100 , 40 ~ 200
Air pressure Ps (MPa)
0.14 ~ 0.4
Flow characteristics
Straight line, equal percentage
Adjustable ratio
50
Allowable leakage
Hard sealing: IV soft sealing: VI
PN(MPa)
1.0 , 1.6 , 4.0 , 6.4
Working temperature t
( ºC )
Normal
-20 ~ 200 , -40 ~ 250 , -60 ~ 250
Cooling
-40 ~ 450 , -60 ~ 450
High
450 ~ 560
Low
-60 ~ -100 , -100 ~ -200 , -200 ~ -250
Performance indicators
Project
Value
Project
Value
Intrinsic error%
No positioner
±5.0
Zero deviation
%
Air close
No positioner
Beginning
±5.0
With positioner
±1.0
Ending
±2.5
Hysteresis error%
No positioner
&#;3.0
With positioner
Beginning
±1.0
Ending
±1.0
With positioner
&#;1.0
Air open
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No positioner
Beginning
±2.5
Ending
±5.0
Dead band%
No positioner
&#;3.0
With positioner
Beginning
±1.0
Ending
±1.0
With positioner
&#;0.4
Allowable leakage
L/h
1×10
-4
×capacity
Rated stroke deviation%
±2.5
Details and dimensions and weight
DN
L
H
H1
Weight(kg)
φA
PN16
PN40
PN64
Normal
High T
PN6
PN16
PN40
Why does my check valve keep leaking?
PN64
PN6
PN16
PN40
PN64
20
180
194
206
398
548
45
52
65
19
23
285
25
185
197
210
410
560
50
57
70
20
24
40
222
235
251
455
620
65
75
85
26
35
50
254
267
286
457
627
70
82
90
30
40
65
276
292
311
610
790
80
92
100
47
66
360
80
298
317
337
622
807
95
100
107
55
78
100
352
368
394
640
850
105
110
117
125
65
99
150
451
473
508
870
132
142
150
172
130
160
470
200
600
650
890
160
170
187
207
175
250
250
730
775
187
202
225
235
350
470
580
300
850
900
220
230
257
265
500
660
Connection dimensions and standards
Flange standard: Cast iron is GB-86 Cast steel is GB-88, JB/T79-94
Flange seal standard: PN10, PN16 is RF, PN40,PN64 is FM, the body is M
Structural length standard: GB-89
Connection of actuator air signal: Internal thread M10×1
The flange and distance of flange end face can be manufactured according to the standard specified by the user. Such as ANSI, JIS, DIN standard.
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Company development
Certifications
Company Show
FAQ:
1. Are you trading company or factory?
We are factory in Yongjia, Wenzhou, China.
2. Are the prodcuts certified?
Yes, ISO, FDA, SIL 2, CE, LFGB and so on.
3. Delivery time?
7-15 working days usually, but it will be longer when peak season.
4.
MOQ?
One set.
Professional Self Regulated Control Valve Manufacturer ...
Self-Regulated Control Valve-FAQ
A self-regulated control valve is used for adjusting the flow by using fluid pressure in the pipe. The flow is adjusted by receiving the energy from the controlled system. It has a simple structure and is economical to use.
The self-regulated valves that control the pressure at its inlet are called self-actuated upstream pressure control valves. They control the pressure at its outlet are known as self-actuated downstream pressure control valves.
This guide will detail the self-regulated control valve, its benefits, drawbacks, specifications, and other properties.
1. What is a self-regulated control valve?
The self-regulated control valve is the pressure-reducing valve and maintains stable secondary pressure without disturbing the primary pressure. The self-regulated pressure valve does not depend on the external signal for controlling pressure; instead, the pressure itself acts as a signal for opening or closing the pressure valve.
A self-regulated control valve controls the pressure at the upstream or downstream side of the control valve. If the pressure upstream is used to accelerate the control valve, the upstream pressure is maintained at a specific set point called the backpressure control valve. This valve is responsible for maintaining the back pressure by the control valve.
If the downstream pressure valve throttles the control valve, then the downstream pressure is maintained at a specific set point called self-regulated control valves.
2. What is the working principle of a self-regulated control valve?
The self-regulated control valve is applicable in various throttling applications and on/off applications. The process fluid is put into the diaphragm or piston, passing through the pilot to maintain the pressure. The pilot controls the main valve&#;s motion of the system. The pressure control requires three functional units, the controller, the measuring equipment, and the final controlling equipment.
The self-regulated control valve is expensive and complex in differential pressure or temperature control tasks. With less downstream pressure, the more trim open, and more downstream pressure causes more trim closing. The spring has the setpoint valve, which can be replaced if a different setpoint is required.
There is a pilot-loaded pressure regulator that uses external gas pressure for getting the pressure regulation set point. The pressure regulator acts as a pilot device to load pressure into the primary.
Regulator&#;s actuating diaphragm. The external load pressure establishes the regulator&#;s setpoint instead of the internal spring of the self-regulated control valve.
You can smoothly adjust the pressure by turning the knob on the pressure regulator, which is also adjustable at this point. The function of the pilot mechanism is to control the primary gas throttling mechanism. The pilot-operated valve is used in liquid service rather than gas.
3. What are the types of self-regulated control valves?
High pressure self-actuated regulating pressure reducing valve
This self-regulated control valve has a forged valve body. It has a nominal pressure of 6.4Mpa, 10Mpa, and 16Mpa and is suitable for high-pressure applications. The high-pressure self-actuated pressure reducing valve has two types, upstream and downstream self-regulating pressure reducing valve.
The downstream pressure makes sure to keep pressure behind the valve constant. It is suitable for oil, water, and non-corrosive gas at a temperature below 350°C.
Self-actuated temperature control valve for steam hot water
It has two main parts, the temperature sensor, and globe valve. It uses the principle of liquid thermal expansion to control pressure. It has a temperature range from -20°C-350°C. The self-operated temperature control valve is categorized into heating type, cooling type, and mixing type.
With the temperature rise, the valve closes that reduces the flow rate. Whenever the temperature decreases below the set value, it increases the flow rate of the medium to increase the temperature.
Self-operated micro pressure reducing regulator
The self-operated micro pressure regulator is divided into a single seat and a double seat. It does not need any external energy, and the actuator controls the position of the spool. The actuator changes the pressure difference and flow and achieves pressure stability and relief for downstream and upstream types.
4. What is the structure of the self-regulated control valve?
The self-regulated control valve consists of a pilot tube that takes the process fluid to pressurize the diaphragm. The diaphragm opens the valve so that the process fluid can pass through. The pilot tube connects the diaphragm to the downstream of the control valve. When the downstream pressure increases in the self-regulated control valve, the pressure is exerted on the diaphragm and closed.
When the valve closes, the process fluid also stops, reducing the downstream pressure to the setpoint level. When it&#;s below the set point, the liquid from the diaphragm goes back to the process line, thus relieving the pressure on the diaphragm. However, it results in the valve opening, increasing the process flow, thus increasing the pressure to its set point.
In the backpressure regulator valve, the diaphragm connects with the upstream of the pressure control valve. The process fluid is responsible for the opening and closing of the valve due to high or low pressure.
5. What are the applications of a self-regulated control valve?
The self-regulated control valve is suitable for pressure, temperature, and differential pressure control in various applications. It is used in applications where there is the deviation of controlled variables from the given set point. These setpoints are usually constant for the entire equipment life. The self-regulated control valve needs auxiliary power to operate the electrical signal. It has an actuator that connects to the valve.
The self-regulated control valve is used widely in gas, clean water, and heat supplier applications. It is a very reliable tool in providing control functions. Even in applications with energy supply failure, the self-regulated control valve is ideal as safety equipment. These valves maintain the inlet and outlet pressure in hygienic applications for dairy, food, and beverage industries.
6. What are the features of a self-regulated control valve?
The self-regulated control valve consists of a control valve, actuator, and a spring for pressure control. It is used for controlling the downstream pressure in the pipes. The control valve is closed when the downstream pressure arises. Some of the features of a self-regulated control valve are as follows:
- It provides upstream and downstream pressure control of non-corrosive liquids and gases.
- There is a feature of automatic adjustment with no external energy.
- The diaphragm in the self-regulated control valve has sensitivity adjustment to the pressure change.
- The piston-cylinder has high-pressure resistance and adjustable travel.
- The control valves are single-seat and sleeve types that provide comprehensive control.
- It has the material of stainless steel bellows which provide zero leak and frictionless stem seal.
- The upstream and downstream pressure of the self-regulated control valve is balanced through stainless steel bellows.
- The wetted parts of the control valve have non-ferrous metal.
- There is a control line kit for direct pressure tapping.
- The self-regulated control valve is maintenance-free with low noise.
7. What are the advantages of a self-regulated control valve?
- It is simple, reliable, and durable equipment with energy consumption.
- The self-regulated control valve is easy to install and operate.
- It provides an accurate flow coefficient with excellent performance.
- It is cost-effective as a self-regulated control valve does not require energy sources. Therefore, there is no need for electricity or gas sources to run it.
- It has accurate flow characteristics and provides good sealing performance.
- You don&#;t need additional axillary energy such as pneumatic or air energy to operate and move the actuator.
- They are widely used to control the pressure of fluids and gases in pharmaceutical and food plants because of their accuracy.
- It is medium controlled with self-operated regulators. It has an easy set point adjustment of the valve.
8. What are the technical specifications of the self-regulated control valve?
- The range of low pressure reducing valves for pressure setpoints ranges from 0.075 to 0.75 psi.
- There is a condensation chamber for liquids or streams to 350°C.
- A safety pressure control valve prevents the leakage and sealing or any rupture indication of the diaphragm.
- The control line kit of the self-regulated control valve provides pressure tapping at the valve body.
- For remote adjustment of the setpoint, there is an actuator.
- The bellow actuator has a set point ranges from 75 to 145, 145 to 320, 290 to 400 psi. The bellow actuator housing has the material of AISI 304, AISI 316Ti.
- The self-regulated control valve has an armored seat or plugs for better wear.
9. What is the principle of operation of the self-regulated control valve?
The medium flows through the valve, and the flow rate is determined by the position of the valve plug and the free area between the plug and seat. The plug stem is connected to the stem of the actuator. For controlling pressure, the diaphragm is joined by the positioning springs and the adjustment nut. The self-regulated control valve is opened by the positioning spring once both the pressures are balanced.
The downstream pressure P² is controlled downstream of the valve. It is transmitted to the operating diaphragm through the control line, changing it into the positioning force. This force adjusts the valve plug and is adjustable at the set point adjustment nut. When the downstream pressure P² rises above the setpoint, the valve closes, and pressure changes.
The valves have the balancing bellows where the downstream pressure acts on the inner surface of bellows, while the upstream pressure works on the outer bellow surface. Thus, it balances the forces produced by the upstream and downstream pressure.
10. What are the components of a self-regulated control valve?
In letdown pressure regulators, no power supply is required, and the failure position is the position it takes if any of the components fail. If the diaphragm or downstream pressure breaks, the regulator opens. The regulator closes when the spring breaks. For overcoming the diaphragm failure, you need to place a relief valve.
Cavitation occurs between the two valves when the pressure inside the valve drops below the vapor pressure of the flowing fluid. It can be overcome with the pressure recovery coefficients of the regulators and cavitation coefficients.
11. How to calibrate a self-regulated control valve?
For testing the proper functioning of the self-regulated control valve, you need to have a regulator and test gauge. First, check the instrument data and pressure requirement. Check the specification sheet of the vendor and the maximum allowable pressure. Open valve A and check the pressure indication on test gauge B with the set pressure.
If the set pressure does not meet the specifications, you need to remove the setpoint adjustment screws of the self-regulated control valve. Adjust the screw until the desired pressure is achieved. This procedure is used for pressure reduction in the control valve.
The second method is the backpressure regulator method, in which the regulator and test gauge are needed as the testing equipment. In this method, you first need to check the instrument data and vendor&#;s specification sheet. The instrument is set up for testing.
Repeat the same procedure by opening valve A and note down the pressure indication of valve B as the set pressure. If the set pressure is not per the specifications, remove the set point adjustment screw and adjust it until the test gauge reaches the desired pressure.
12. What are the essential parts of a self-regulated control valve?
The self-regulated control valves are used to control and maintain pressure in various applications. The self-regulated control valves are standard in the gas industry, while the pilot regulated control valve is suitable in high flow situations. The self-regulated control valve consists of three main parts:
- A measuring element
- A loading element
- A restrictive element
The loading element is weight, spring, or pressure from some external source. When you compress the spring, it produces a loading force. The diaphragm connects to the process fluid, which creates a force against the loading force.
The restrictive element is connected to the spring. The diaphragm regulates the flow through the regulator. In the self-regulated control valve, the downstream pressure decreases the spring force. This force overcomes the gas on the diaphragm causing the valve to open and increase the flow. The increase in pressure closes the valve and reduces the flow.
13. How to best use a self-regulated control valve?
The self-regulated control valve is a cost-effective and optimized pressure measuring solution used in various distribution networks. The tricky task is to purchase a suitable self-regulated control valve for your application. When there are changes in the physical environment of the valve, the self-regulated control valve responds by opening or closing.
A differential pressure regulator applies the pressure of the fluid against the diaphragm. The diaphragm uses a spring to get force balance with the diaphragm at the set pressure. You need to maintain higher differentials between temperature and flow in heating systems to get the most out of energy.
If you want to achieve the high efficiency of the self-regulated control valve, the balanced flow control system is preferred, ensuring a balanced supply of heating and cooling in all installation parts. In addition, the control valves use downstream to maintain accurate performance.
The pressure-independent control valves are successful in providing cost-effective control within the distribution networks. Another important factor is considering the low supply and centralized distribution factors for getting the balanced heating system. The self-regulated control valve is the self-controlling valve that does not need any further input. Therefore, it provides the best performance and proper levels.
14. What are the safety precautions of using a self-regulated control valve?
- Some preventive measures need to keep in mind while you are operating a self-regulated control valve. Some safety precautions are as follows:
- Before using a self-regulated control valve, inspecting the regulator and valve before using it is essential.
- It is recommended to avoid connecting the valves and regulators to the supply source, which has a higher pressure than the regulator&#;s maximum rated pressure.
- Read the product label specifications carefully. If there is no rate pressure, contact your representative for the rated pressure installation and use.
- Before the installation of regulators and valves, establish the flow direction of the fluid. It is the primary duty of the user to install the equipment properly.
- When you are installing the self-regulated control valve, do not over-tighten the components in the pressurized system.
- If there is any malfunction in the self-regulated control valve or case of any leakage, immediately take it out of service.
- While applying pressure, make it gradual to avoid any sudden pressure shock to the equipment.
15. How does the self-regulated temperature control valve work?
Self-regulated temperature control valves do not depend on external power sources to regulate the temperature in various systems. For example, these are commonly used for boiler temperature adjustment by maintaining a linear relationship between temperature and the valve.
For operating the self-regulated temperature control valve, the sensor is inserted into the pipeline&#;the change in temperature results in the opening of the valve. If the temperature rises, the sensor is heated and expands capillary to close the valve.
Once the temperature changes, the liquid volume changes. This change is transmitted through the capillary tube while the actuator acts on the valve stem. When the temperature is heated, it will close the valve. When the temperature is cooled, it opens the valve.
16. What is the installation method of a self-regulated control valve?
There are some techniques and strategies for installing the self-regulated control valve. While installing, make sure that the valve body is installed at the inlet of the primary heat medium. The valve stem is positioned upwards to make sure that the self-regulated control valve has a vertical position. Finally, you need to install a filter at the inlet of the self-regulated control valve.
Install on/off valve on the inlet and outlet of the control valve. Insert the sensor around the outlet and carefully observes the valve stem and capillary tube during installation.
17. What are the parameters of a self-regulated control valve?
The body type of the self-regulated control valve is single-seated and globe type. The trim material is made of stainless steel. The temperature ranges from -5°C to +70°C.
It is used widely for the pressure-reducing stabilization for gases, liquid, and steam. The design and manufacturing of the self-regulated control valve are manufactured according to the standard of AMSE/API/BS/GB.
The accuracy range is within ±5%, and the connection is flanged or socket welding. The pressure class of the self-regulated control valve is 1.6, 4.0, and 6.4 Mpa.
18. What is the difference between a self-regulated control valve and a pilot-operated pressure-reducing valve?
The self-regulated control valve uses flow pressure in the pipe to adjust the flow. It controls and manages the secondary stress without affecting the primary force. In contrast, The pilot-operated pressure-reducing valve allows flowing from inlet to outlet port in the system. The self-regulated control valve is operated by the diaphragm that adjusts the primary pressure to a piston.
The self-regulated control valve reduces and balances the excess pressure in the system. The essential function is to relieve stress from higher to lower. The self-regulated control valve is suitable in applications where precise pressure control is required for larger loads. It is famous for gas and steam flow control. If the medium is liquid, the liquid should be clean without dirty.
Pilot operating pressure valves reduce the pressure in the pipeline; they are cheaper. Its structure consists of a pilot valve for loading a diaphragm. It increases the force to open the valve. The pilot-operated pressure reducing valve has the advantage of tight downstream pressure control. It has a wide application for gas, liquid, oil, steam, etc.
The pilot-operated pressure deducing valve has the same components as the self-regulated control valve: diaphragm, plug, seat, and spring. It has the added component of a pilot, which separates P2 from the loading force. The pilot connects with the downstream piping, which provides accurate measuring of the pressure conditions.
Conclusion
A self-regulated control valve is an important tool for adjusting the flow in various applications. The self-regulated control valve is used widely in different industries, such as petroleum, electric power, food, metallurgy, textile, machinery, and construction buildings.
At BCST, we provide high-quality and reliable self-regulated control valves to meet the specific requirement of your application. You can contact us any time in case of any queries.
For more information, please visit pneumatic globe valve.