Qfh42h Air Valve Type Check Valve

• Media: Water-Vapour Oil
• Temperature: Low Temperature
• Material: Stainless Steel Carbon Steel Brass
• Connection Form: Flange Welding
• Structure: Swing
• Pressure: High Pressure, Medium Pressure and Low Pressure
• Model NO.: QFH42H
• Function: Ddcv Double Lobe, Nrvr Silence, Sfcv Rubber Lobe, Nrvz Silence, Nrvg Silence
• Sealing Form: Hard Seal and Soft Seal
• Flow Direction: Unidirection
• Standard: DIN GB ANSI Bsw JIS
• Application: Industrial Usage, Water Industrial Usage, Household Usage
• Transport Package: Wooden Box
• Specification: DN15-DN800
• Trademark: XC
• Origin: China
• HS Code: 8481804090
• Production Capacity: 9999

Product Description

I. Product Overview:
QFH42H air valve type check valve is specially designed for gas system. Depending on the difference in air flow conditions, the valve can be used either as a constant flow check valve, which always remains fully open regardless of the presence or absence of small flow fluctuations in the system, or as a pulsating flow check valve, which opens and closes with an air flow pulse. The channel at its seat is annular, and this valve has a small opening and the ability to close quickly. With the small action of the spring, the valve plate has responded to the change of gas pressure difference on both sides of the valve at the moment before the gas reaches the reflux condition, and it fits with the valve seat to prevent the gas backflow after a very small movement distance.
 
Second, structural characteristics:
QFH42H air valve type check valve is mainly composed of upper body and lower body, seat, valve plate, lift limiter, spring, screw, nut and other parts. The valve body is made of WCB or 304 and other materials, and the upper and lower valve body is fixed by double-headed screw and screw nut. The valve clamp seat and valve plate, the valve seat and the valve body fixed clamping gasket to prevent gas leakage. The valve seat is annular, and each ring is independent, so there may be asynchronous phenomenon in the movement. The valve seat has a gas channel that can be covered by the valve plate, and together with the valve plate, the airflow channel is blocked, and the pressure difference between the inlet and outlet in the pipeline is borne; The opening and closing element is between the ring clamp and the seat valve and the lift limiter, alternately opening and closing the seat channel, controlling the gas in and out of the working chamber, also known as the valve plate. Valve plate with metal, complex structure, difficult to process can withstand the pressure difference of more than 7MPa, exhaust temperature of more than 250°C, can be used for oxygen and LV gas, good reliability and durability.
 
Three, the working principle:
QFH42H valve type check valve in the direction of the length of the gas leakage gap to create some small chambers, the leaking gas does not enter a small chamber expansion once, the pressure is reduced, the volume is increased, so that the pressure drop of the gas through each small chamber is more and more large, can not leak smoothly, to achieve the purpose of sealing. When the gas flows in the valve gap, it is regarded as an incompressible fluid, so its average flow rate. Constant flow check valves can be used in centrifugal pumps, Roots compressors, screw compressors or reciprocating compressors when the flow pulsation is not enough to cause a flutter. Pulsating check valves are used in reciprocating compressor systems if the flow pulsation can cause the valve to open and close accordingly, so that they can withstand repeated shocks between sealing surfaces.
 
Four, parts materials:

Body material	Carbon steel WCB, stainless steel 304, 316,
Core material	Stainless steel, stainless iron
Materials	TetrafluoroPTFE
Ambient temperature ºC	425 or less
Nominal pressure (MPa)	0.001 ~ 5.0
Explosion-proof rating	BS5501:A, B, C