Pneumatic Diaphragm Three-way Control Valve

Pneumatic diaphragm three-way control valve uses compressed air as the power source, pneumatic diaphragm as the actuator, and under the help of the valve positioner, converter to drive the valve open or close, to achieve proportional adjustment to the valve opening for controlling the flow, pressure, temperature and other process parameters of the medium.

When the air pressure is input into the air chamber, the film generates thrust force, which makes the thrust disk move to compress the spring to drive the valve stem move downwards or upwards to implement valve action open/close. There is a proportional relation between the valve’s opening and the air source pressure.

Product Description

Valve body structure:

3 way valve body

1-Body,   2- Gasket,   3-Seat,   4-Valve plug,   5- Gasket,   6-Bonnet,   7- Packing,   8- Packing bushing,   9- Gland,   10-Stem,   11-Hex nut,   12-Stud,   13- Hex nut,   14-Stud


Main technical data:

● Valve body

Type Conveging three-way / divider three-way casting globe type, double seat
Size (DN) 25 ~ 300 mm
Pressure rating PN16 ~ PN100  / CL150LB, CL300LB, CL600LB
Flange standard JB/T79.1-94, 79.2-94, ANSI B16.5
Body material WCB, CF8, CF8M
Bonnet structure Standard type: (-5 ~ 230 ℃), Heat dissipation type:(-45 ~ 230 ℃), Low temperature type:(-196 ~ -45 ℃), Bellow sealed type
Bonnet type Bolted
Packing V-type PTFE / flexible graphite
Trim structure Single-seat / plunger disc
Trim material Seat & Plug: SS304/SS316 surfacing welding Stellite,  Shaft: SS304/SS316
Flow characteristic Equal percentage / Linear


● Performance

Flow characteristic Linear,  percentage
Allowable range 50:1 ( CV<6.3 30:1)
Rated Cv value Percentage CV1.6 ~ 630, Linear CV1.8 ~ 690
Leakage grade Metal seal: IV grade ( 0.01% rated capacity )
Soft seal: VI grade (leakage standard: GB/T 4213)
Intrinsic error ±1.5 %
Return difference ≤1.5 %
Dead zone ≤0.6 %
Difference from beginning to end ±2.5 %
Rated travel difference ≤2.5 %
Note:  Performance listed base on the packing material in PTFE


● Actuator

Type Pneumatic diaphragm actuator (multi-spring type)
Usage Regulating,  ON-OFF
Air supply pressure Air supply pressure ( Spring range)
140 ( 20 ~ 100) Kpa G
240 ( 40 ~ 200) Kpa G
280 ( 80 ~ 240) Kpa G
Input signal 4-20mA.DC
Action to close pressure increase, valve stem descend, valve close
Action to open pressure increase, valve stem ascend, valve open
Lag ≤1 %FS ( with positioner )
Linear type ≤2 %FS ( with positioner )
Environmental temperature  -10℃ ~ +70℃
Accessories E/P, P/P valve positioner, filter regulator, valve converter, solenoid valve, Limited switch.





Answer : Please send your question or enquiry to our email:, we will forward the questions to the related engineer.

Answer :  Please communicate with the sales about the return procedure before returning product.

Answer :  The delivery time depends on the order quantity and product specification.  If the product’s specification is conventional ( not special ),  delivery time is 5 or 7 working days for order quantity ≤ 10 pieces;  delivery time is 2 or 3 working weeks for order quantity 15 ~ 30 pieces. 

Answer :  by Courier,  by Sea or by Air

Answer :  Yes,  Generally warranty is one year.

Answer :  From year 2015  to year 2021,  average annual sales is RMB 350 million ( about USD 54.7 million )

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