Pneumatic Diaphragm Double Seat Control Valve

Technical Parameter

Product model: ZMAN, ZJHN

Nominal diameter: DN25~300mm

Pressure range: PN1.6~6.4MPa

Temperature range: -40℃~+450℃

Flange size: GB/T9113.2-2000

Body form: double-seat straight-through

Valve material: WCBZG230-450, ZG1Cr18Ni9Ti

Spool material: 1Cr18Ni9Ti (304) or Stellite alloy surfacing

Sealing packing: V-type PTFE (F4), flexible graphite, stainless steel bellows


Product Detail

Product overview

The dynamic diaphragm double-seat control valve is composed of a multi-spring pneumatic diaphragm actuator and a straight-through double-guided double-seat valve. It has the characteristics of compact structure, light weight, sensitive action, small pressure drop loss, large valve capacity and accurate flow characteristics. Compressed air drives the valve stem and valve core to control and adjust the flow medium, which can realize the automatic adjustment and control of the fluid medium in the process pipeline. Widely used in petroleum, chemical, pharmaceutical, metallurgy, power station and other industrial control fields, mainly controlling gas, liquid, steam and other media.


Structural features

1. Pneumatic film actuator is used to configure the positioner to achieve precise adjustment and control of the process parameters of the fluid medium;

2. Positive action of the actuator: air-closed-normally open type (the valve position moves downward when the signal pressure increases), "Type B";

3. Actuator reaction: air open type - normally closed type (when the signal pressure increases, the valve position moves upward), "K type";

4. Double-seat plunger valve core is suitable for medium with large pressure difference, large flow and not very clean and occasions where leakage requirements are not strict.


The main technical parameters

Nominal diameter (DN)253240506580100125150200250300
Seat Diameter (dn)253240506580100125150200250300
Rated flow coefficient (KV)Straight line12.519.530.548.47612519530548476010001600
Equal percentage1117,627.544691101762754406909001300
Allowable differential pressure (MPa)≤ Nominal pressure
Nominal pressure (MPa)1.6、2.5、4.0、6.4、10.0
Rated stroke (mm)16254060100
Equipped with actuator modelZHA/B-22ZHA/B-23ZHA/B-34ZHA/B-45ZHA/B-56
Bonnet formStandard type (-17~+250℃), high temperature type (+250~+450℃), low temperature type (-40~-196℃), bellows seal type (-40~+350℃)
Gland formBolt compression
Seal packingV-type PTFE packing, V-type flexible graphite packing
Spool formDouble seat plunger guided spool
Flow characteristicsLinearity, equal percentage


Actuator technical parameters

Configure Actuator ClassZHA/B Multi-spring diaphragm actuator
Actuator modelZHA/B-22ZHA/B-23ZHA/B-34ZHA/B-45ZHA/B-56
Effective area(cm2)3503505609001400
Stroke(mm)10、16244040、60100
Spring range (KPa)20~100 (standard), 20-60, 60-100, 40-200, 80-240
Diaphragm materialNitrile rubber with nylon cloth, ethylene propylene rubber with nylon cloth
Air supply pressure140~400KPa
Air supply interfaceRC1/4"
Ambient temperature-30~+70℃
Accessories availablePositioner, air filter pressure reducer, position retaining valve, travel switch, valve position transmitter, hand wheel mechanism, etc.
Form of actionAir-to-close (B)—valve open (FO) when gas is lost; air-to-open (K)—valve to be closed when gas is lost (FC)


Material of main parts

1BaseWCB304316316L
2BodyWCB304316316L
3Spool304304316316L
4Seat304304316316L
5Copper setsBrass
6Guide sleeve304304316316L
7GasketPTFE\Graphite GasketPTFE\Graphite GasketPTFE\Graphite GasketPTFE\Graphite Gasket
8BonnetWCB304316316L
9Stem304304316316L
10PackingPTFE/GraphitePTFE/GraphitePTFE/GraphitePTFE/Graphite
11Packing glandWCB304316316L
12Bolt250Cr18Ni9Ti1Cr18Ni9Ti1Cr18Ni9Ti


Main performance indicators

ProjectWithout locatorWith locator
Basic error %±5.0±1.0
Return difference %3.01.0
Dead zone%3.00.4
Always point deviation %Open airStarting±2.5±1.0
Starting±5.0±1.0
Air passStarting±5.0±1.0
End±2.5±1.0
Rated stroke deviation%≤2.5
Leakage L/h0.01%×valve rated capacity
Adjustable range R30:1


Main connection size

Nominal diameter 

DN(mm)

253240506580100125150200250300
LPN16/25185200220250275300350410450550670770
PN40190210230255285310355425460560740805
PN64200210235265295320370440475570750820
HPN16/25117120139144188208220268278320441503
PN40124128145150195220230280290335465528
PN64130135155170205240255295310360480550
H1165185185205245255270335365430560680
H2298298298298380380380510510510650650
H3177177177177182182182182182218218218
L1280280280280350350350475475475560560
A282282282282360360360470470470580580
D220220220220270270270320320320400400