Pneumatic Diaphragm Single-Seat Control Valve

The oxygen specific shut-off valve is made of high-quality silicon brass or stainless steel casting, which has the advantages of high mechanical strength, wear resistance, and good safety. Used on oxygen pipelines, it has effective explosion-proof and flame-retardant properties, eliminating unsafe factors on oxygen pipelines.

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Control Valve Series

Keyword： Pneumatic Diaphragm Single-Seat Control Valve

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I. Pneumatic Diaphragm Single-Seat Control Valve – Product Overview
The ZJHP pneumatic diaphragm single-seat control valve boasts advantages such as a compact design, lightweight construction, sensitive operation, minimal pressure drop loss, large valve capacity, precise flow characteristics, and convenient maintenance—making it suitable for demanding operating conditions. This pneumatic diaphragm single-seat control valve consists of a multi-spring pneumatic diaphragm actuator paired with a low-flow-resistance, compact single-seat valve body. The accompanying multi-spring actuator features a low profile, lightweight design, and straightforward installation. When equipped with a valve positioner, the pneumatic diaphragm single-seat control valve converts an incoming current signal into a corresponding linear displacement, automatically regulating the valve’s opening degree. This ensures continuous control over critical process parameters in pipelines, such as fluid pressure, flow rate, temperature, and liquid level. Widely used for precise control of gases, liquids, steam, and other media, the ZJHP pneumatic diaphragm single-seat control valve is particularly well-suited for applications where small pressure differentials are required, while also maintaining low leakage rates—even under moderate pressure differences.
II. Pneumatic Diaphragm Single-Seat Control Valve – Technical Specifications

Nominal Diameter (DN)		20	25	32	40	50	65	80	100	125	150	200	250	300
Valve seat diameter (DN)		20	25	32	40	50	65	80	100	125	150	200	250	300
Rated Flow Coefficient KV	Straight line	6.9	11	17.6	27.5	44	69	110	176	275	440	630	875	1250
Rated Flow Coefficient KV	Equal percentage	6.3	10	16	25	40	63	100	160	250	360	570	850	1180
Allowable Pressure Differential (MPa)		3.2	3	2	1.8	1.5	1.4	1	0.7	0.6	0.5	0.3	0.2	0.1
Nominal Pressure (MPa)		1.6 / 2.5 / 4.0 / 6.4 / 10.0
Rated Stroke (mm)		16			25		40			64			100
Actuator Model		ZHA/B-22		ZHA/B-23			ZHA/B-34			ZHA/B-45			ZHA/B-56
Valve cover type		Standard type (-17 to +250°C), high-temperature type (+250 to +450°C), low-temperature type (-40 to -196°C), and bellows-sealed type (-40 to +350°C)
Gland type		Bolt-clamping type
Sealing Gasket		V-shaped PTFE packing, V-shaped flexible graphite packing
Valve core type		Single-seat plunger-type valve spool
Flow Characteristics		Linearity, Equal Percentage

3. Pneumatic Diaphragm Single-Seat Control Valve – Actuator

Configure the actuator category	ZHA/B Multi-Spring Diaphragm Actuator
Actuator Model	ZHA/B-22	ZHA/B-23	ZHA/B-34	ZHA/B-45	ZHA/B-56
Effective Area (cm²)	350	350	560	900	1400
Travel Distance (mm)	10, 16	24	40	40, 60	100
Spring range (kPa)	20–100 (Standard), 20–60, 60–100, 40–200, 80–240
Membrane material	Nitrile rubber-coated nylon fabric, EPDM rubber-coated nylon fabric
Gas supply pressure	140–400 LPA
Air source interface	RC 1/4-inch
Environmental humidity	Minus 30°C to +70°C
Attachable accessories	Positioners, air filter regulators, hold-position valves, limit switches, valve position transmitters, handwheel mechanisms, and more
Mode of action	Air-to-close (B) – valve opens (FO) when air supply is lost; Air-to-open (K) – valve closes (FC) when air supply is lost

IV. Pneumatic Diaphragm Single-Seat Control Valve – Performance Specifications

Project			Without a locator	With a locator
Basic error %			±5.0	±1.0
Hysteresis %			3	1
Dead Zone %			3	0.4
Always Point Deviation %	Air-to-open	Starting point	±2.5	±1.0
	Air-to-open	Starting point	±5.0	±1.0
	Air-to-close	Starting point	±5.0	±1.0
	Air-to-close	End point	±2.5	±1.0

5. Pneumatic Diaphragm Single-Seat Control Valve – Component Materials

Serial Number	Part Name	Part material
1	Valve body	WCB (ZG25)	CF8 (304)	CF8M(316)	CF3M (316L)
2	Gasket	304	304	316	316L
3	Valve seat	304	304	316	316L
4	Valve core	304	304	316	316L
5	Guide sleeve	304	304	316	316L
6	Middle pad	PTFE/Metal-Graphite Wound Gasket
7	Valve cover	WCB (ZG25)	CF8 (304)	CF8M(316)	CF3M (316L)
8	Valve stem	304	304	316	316L
9	Filler	PTFE, Graphite
10	Cap seal	WCB (ZG25)	CF8 (304)	CF8M(316)	CF3M (316L)

6. Pneumatic Diaphragm Single-Seat Control Valve – Connection Dimensions

Nominal Diameter (DN)		20	25	32	40	50	65	80	100	125	150	200
Valve seat diameter (DN)		20	25	32	40	50	65	80	100	125	150	200
L	PN16/25	181	184	200	222	254	276	298	352	410	451	600
	PN40	194	197	200	235	267	292	317	368	425	473	610
	PN64	206	210	210	251	286	311	337	394	440	508	650
H	PN16/25	52.5	57.5	75	75	85.5	92.5	100	110	142.5	158	170
	PN40	52.5	57.5	75	75	85.5	92.5	100	117.5	150	167.5	187.5
	PN64	65	40	85	85	90	102.5	107.5	125	172.5	195	207.5
H1		132	132	158	170	179	214	221	234	270	294	331
H2		298	298	298	298	298	380	380	380	510	510	510
H3		180	180	180	180	180	236	236	236	310	310	310
L1		289	289	289	289	289	347	347	347	476	476	476
A		282	282	282	282	282	360	360	360	470	470	470
D		220	220	220	220	220	270	270	270	320	320	320

7. Pneumatic Diaphragm Single-Seat Control Valve – Selection Parameters
(1) Valve Body Parameters: Key parameters of the valve body include nominal diameter, working pressure, process medium, application environment, and valve body material, among other series-specific details.
(2) Actuator Parameters: Actuator type, control method, control signal (4–20mA, 1–5V), and action mode (air-to-open, air-to-close)