COVNA Products

COVNA Pneumatic Diaphragm Regulating Control Valve with Digital Display

The pneumatic control valve is composed of an actuator and an adjustment mechanism. The actuator is the thrust component of the adjustment valve. It generates a corresponding thrust according to the pressure of the control signal to push the adjustment mechanism into action. The valve body is the regulating component of the pneumatic regulating valve. It directly contacts the regulating medium to regulate the flow, pressure, temperature and other process parameters of the fluid. The pneumatic control valve has the characteristics of simple control, fast response, and intrinsically safe, without additional explosion-proof measures. Pneumatic control valve is one of the industrial process control instruments widely used in petroleum, chemical, electric power, metallurgy and other industrial enterprises.
Model: pneumatic control valve
Size Range: 3/4”~8′
Pressure Range: PN16~PN100
Material: WCB, Stainless steel，HT200、ZG25I、ZG1Cr18Ni9、ZGOCr17Ni12Mo2、1.25Cr0.5Mo、5.0Cr0.5Mo、 SCPH21、Ti

Pressure：PN10-PN64 CL150-CL600
Medium：Water,steam,oil,etc.
Temperature :100～450℃
Body material：WCB,WC6,WC9,CF8,CF8M,etc.

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Advantages of Pneumatic Diaphragm Regulating Valve with Digital Display:

● It is cost-effective and safe to be used,which can help you save cost of the whole system and maintenance.
● It has a simple structure and a big torque, explosion-proof with short actuating times,optimized actuating forces and reliable tight sealing.
● It can perfectly avoid problems of friction, corrosion, and emissions.
● It is of low center of gravity, high vibration resistance and easy to install.
● Simple to control, rapid response, and intrinsic safety, no need to take additional explosion-proof measures.
● Fluid channels in a s- shaped streamline, small pressure drop loss large flow, wide adjustment range, high precision flow .

 

By receiving the control signal pressure output by the standard electric signals of the regulator(via electricity-air positioner or electricity-air converter), the valve opening is changed, so as to change the flow of the medium to be regulated and then allow parameters such as flow, pressure, temperature and liquid level to be regulated. As a result, the production process automation is achieved.
After the extraneous pneumatic pressure signal is input into the diaphragm chamber, it will act on the diaphragm to produce thrust. The thrust them compress the spring pack, and move the push rod, which drives the spindle to open(close) of the valve clack until the balance is achieved between the thrust and reaction of the compressed spring pack and the clack is in a stable position of the stroke. It is concluded from the above principle. There is a definite proportional relation between the clack and the input pressure signal.

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Working Principle Of high temperature Pneumatic control valve

By receiving the control signal pressure output by the standard electric signals of the regulator(via electricity-air positioner or electricity-air converter),the valve
opening is changed, so as to change the flow of the medium to be regulated and then allow parameters such as flow, pressure,temperature and liquid level to be regulated. As a result, the production process automation is achieved.
After the extraneous pneumatic pressure signal is input into the diaphragm chamber, it will act on the diaphragm to produce a thrust. The thrust then compress the spring pack, and move the push rod, which drives the spindle to open (close) of the valve clack, until the balance is achieved between the thrust and reaction ofthe compressed spring pack and the clack is in a stable position of the stroke.It’s concluded from above principle, There’s a definite proportional relation between the clack and the input pressure signal.

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Technical Parameters of Valve Actuator :

Nominal Size DN (mm) 20 25 32 40 50 65 80 100 125 150 200 250 300
10 12 15 20
Rated Flow Coefficient CV High accuracy flow characteristic clack 1.6 2.5 4.0 6.3 10 17 24 44 68 99 175 275 360 630 900 1440
High capacity flow characteristic clack 1.8 2.8 4.4 6.9 11 21 30 50 85 125 200 310 440 690 1000 1600
Rated Stroke(mm) 10 16 25 40 60 100
Effective Diaphragm Area cm2 280 400 630 1000 1600
Inherent Regulation Ratio 50:1
Nominal Pressure MPa 1.6 / 4.0 / 6.4
Sevice Temperature -100~-60℃; -200~-100℃; -250~-200℃
Ambient Temperature -30~70℃
Air Supply Pressure KPa 0.14 / 0.25 / 0.40
Spring Range KPa 20~100(Basic type) / 40~200 / 80~240
Connection Thread G1/4″ , M16X1.5

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Performance of High Temperature Pneumatic Control Valve:

High temperature pneumatic control valve
Flow characteristic		 Linear, percentage, quick open
Allowable range 50: 1 (CV<6.3 30: 1)
Rated Cv value Percentage CV1.6~630 ，linear CV1.8~690
Pneumatic control valve Allowable leakage Metal seal:  IV grade（0.01% rated capacity）
Leakage standard:  GB/T 4213
High temperature pneumatic control valve Performance
Intrinsic error % ±1.5
Return difference, % ≤1.5
Dead zone, % ≤0.6
Difference from beginning to end point, % ±2.5
Rated travel difference, % ≤2.5

Dimension of ZJH Series Pneumatic Diaphragm Control Globe Valve:
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Weight table of Pneumatic diaphragm regulating valve
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Company Profile:
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Factory Profile:
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Company Certificates:
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Package & Shipping:
As a professional electric ball valve manufacturer, COVNA aims to provide our customers the best quality products with the most competitive pricing, on-time delivery and full warranty service with omprehensive service from start to finish, encompassing consultation through to after sales service, full support in every respect and ensure that you are accompanied at each stage of your project.

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●22 years manufacturer of actuated valves

●Mass customaztion acceptable. 3 production base, large stock,

●Short lead time, same day shipping.

●German imported manufacturing facilities, 100% Q.C passed before shipping, quality assured.

●Industrial standard 1 year (12 months) warranty.

●ISO 9001 certificated, with extra certifications include CE, TUV, RoHS, SGS, BV, explosion & fire safe.

●OEM / ODM  service available. Can do JIS 5K / 10K, ANSI 150lb / 300lb / 600lb / 900lb standard.

●More infomation, pls send message to us. Quote will be provided within 2 hours!

Technical Parameter of Actuators:

Nominal Diameter G 3/4″ 20 25 40 50 65 80 100 150 200 250 300
Valve Seat Diameter 3 4 5 6 7 8 10 12 15 20 20 25 25 32 40 32 40 50 40 50 65 50 65 80 65 80 100 100 125 150 125 150 200
Rated Flow Coefficient Cv High Accuracy Flow Characteristic Clack 0.08 0.12 0.20 0.32 0.50 0.80 1.8 2.8 4.4 6.9 6.9 11 11 17.6 27.5 17.6 27.5 44 27.5 44 69 44 69 110 69 110 176 176 275 440 275 440 690 1000 1600
High Capacity Flow Characteristic Clack 1.6 2.5 4 6.3 6.3 10 10 16 25 16 25 40 25 40 63 40 63 100 63 100 160 160 250 400 250 400 630 900 1440
Rated Strock(mm) 10 16 25 40 60 100
Effective Diaphragm Area (cm2) 220 350 560 900 1400
Inherent Regualtion Ratio 50:1
Nominal Pressure MPa 0.16 1.6 4.0 6.4 (ANSI125 150 300 600LB)(JIS10 16 20 30 40K)
Sevice Temperature -20 to 200℃  -40 to 250℃  -40 to 450℃  -60 to 450℃
Ambient Temperature -40 to 85℃
Air Supply Pressure KPa 0.14(0.25 0.4)
Spring Range KPa 20 to 100(40 t o200  80 to 40  20 to 60  60 to 100)
Connection Threaded Female Thread M10×1

 

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  1. Oil and Gas Industry
    • Pipeline Flow and Pressure Control: Used for flow and pressure control in natural gas and oil pipelines to ensure stability during transportation.
    • Gas and Liquid Distribution Systems: Regulates the flow of gases or liquids, ensuring precise control under various operating conditions.
    • Automation of Distribution Systems: Used in refineries and natural gas processing plants to automate fluid distribution and regulate the reaction processes.
  2. Chemical and Petrochemical Industry
    • Reactor Pressure and Flow Control: Used in chemical reactors, storage tanks, and other equipment to control pressure and flow, ensuring stability in the chemical reaction process.
    • Flow/Pressure Regulation: Regulates the flow of liquids or gases in processes such as polymerization, refining, and distillation to ensure efficient production.
    • Steam Control: Regulates the flow and pressure of steam in steam generators and distribution systems.
  3. Water and Wastewater Treatment
    • Water Flow Control: Regulates water flow and pressure in water supply and wastewater treatment systems to ensure normal operation.
    • Gas and Chemical Additions: Regulates the flow of chemicals or gases (such as chlorine or ammonia) added during the water treatment process.
  4. HVAC (Heating, Ventilation, and Air Conditioning) Systems
    • Temperature Control and Airflow Regulation: Used in air conditioning systems to regulate the flow of cooling or heating fluids to maintain the desired temperature.
    • Pressure and Airflow Regulation: Adjusts the flow and pressure of air in ventilation, air conditioning, and humidification systems to ensure indoor comfort.
  5. Food and Beverage Industry
    • Liquid Flow Control: Precisely controls the flow of liquids in processes such as brewing, dairy production, and beverage bottling.
    • Temperature and Pressure Regulation: Regulates temperature and pressure during heating, cooling, and sterilization to ensure product quality and safety.
  6. Pharmaceutical Industry
    • Precision Flow Control: Regulates the flow of liquids and gases in pharmaceutical manufacturing processes to ensure precise control of process parameters.
    • Pressure Control: Adjusts pressure in cleaning and sterilization systems to ensure stable system operation.
  7. HVAC Systems
    • Airflow and Temperature Control: Controls the flow and temperature of air to adjust environmental conditions, ensuring comfort and energy efficiency inside buildings.
  8. Steel and Metallurgical Industry
    • Gas Flow Control: Precisely adjusts the flow of gases such as oxygen and nitrogen during smelting and heating processes to ensure stable furnace temperatures and chemical reactions.
    • Cooling Fluid Flow Regulation: Regulates the flow of cooling fluids in cooling systems to ensure temperature control of equipment.
  9. Thermal and Power Industry
    • Steam and Water Flow and Pressure Control: Regulates the flow of steam and water in boiler systems, heat exchangers, and power plants to ensure efficient operation of thermal systems.
  10. Mining Industry
  • Slurry Flow Regulation: Adjusts the flow and pressure of slurry during transportation and separation processes to ensure efficient extraction and processing of minerals.
The actuator on my automated valve operates, but the valve won’t turn. Why?

Most likely the valve stem or actuator coupling is broken.

The electric actuator limit switches or the pneumatic actuator position stops are not correctly adjusted.

Probably because there is no air pressure to the solenoid or dirt has jammed it. Also, debris might be trapped inside the valve. Or, the air pressure is not sufficient to operate the actuator. Remember: measure air pressure at the actuator, not at the compressor.

Maybe. First, be sure that the actuator torque output is sufficient to turn the valve reliably. Second, you will have to fabricate a custom mounting bracket and coupling to connect the actuator to the valve.

The valve will stop somewhere between full open and close. When power is reapplied to the original circuit, the actuator will complete the cycle.

To make the change just remove the actuator from the valve and turn it, or the valve stem, 90 degrees and remount the actuator.

Remove the actuator from the valve and check the valve stem. Most ball valves have stem flats at right angles to the flow when the valve is in the off position. On butterfly valves check the stem flow arrow marking.

Remove the actuator from the valve and check the valve stem. Most ball valves have stem flats at right angles to the flow when the valve is in the off position. On butterfly valves check the stem flow arrow marking.

Check the electric wiring schematic that came with the actuator for the correct hookup. Sometimes a copy is inside the actuator cover. If it is missing, don’t guess about the connections. Call the manufacturer for a schematic.

The actuator is wired incorrectly (check the schematic accompanying the actuator), or the external control switch is not the correct type for the actuator.

Not unless you bought it with an optional speed control.

Actuators and solenoid valves require different types of electrical control switches. SPDT for actuators, SPST for solenoids. Check the actuator wiring schematic for the correct wiring and switch type.

Still have confused? Contact Us!
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