These vacuum pressure vent valves are used in gas stations or oil storage depots. The vent valve typically consists of two parts: a pressure valve and a vacuum valve designed to be installed inside. It is usually installed at a height of approximately 4.5 meters on the vent pipe of the oil storage tank to maintain the tank's tightness under normal circumstances.They protect tanks from excessive over or under pressure. The vent cap and internal wire screen are designed to protect the tank vent lines against intrusion and blockage from water, debris or insects. A normally closed poppet in the valve, opens at a predetermined pressure or vacuum setting to allow the tank to vent.

HYZQF-50 Vacuum Pressure Vent Valve
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Technique Specification: Body: Aluminum Cap: Aluminum Screen: 40 Mesh Stainless steel mesh Gasket: Buna-N or Viton for option Temperature Range:-20~+50℃ Positive:+3 inches of water column for the international market + 9 inches of water column for the domestic market Negative: -8 inches of water column
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Order Specifications:
| Model |
Connection Method |
| HYZQF-40 |
Female 1.5 inch Thread BSPP or NPT Standard (If necessary) |
| HYZQF-50 |
Female 2-inch Thread BSPP or NPT Standard (Regular Item) |
| HYZQF-50F |
2-inch Aluminum Flange |
| HYZQF-65F |
2.5-inch Aluminum Flange |
| HYZQF-80F |
3-inch Aluminum Flange |
Standard of connecting flange can be produced according to the client’s detailed requirements.
Important Note: These vents should not be used on an underground storage tank (UST) with a throughput of 100000 gallons or more per month.
Features:
It reduces oil evaporation losses to a certain extent. When necessary, it can automatically open and adjust to maintain a balanced pressure inside and outside the tank, serving a safety function for the tank.
When the vapor pressure in the tank exceeds the allowable pressure, oil vapor is released through the pressure valve, while the vacuum valve remains closed.
When the vapor pressure in the tank is lower than the allowable vacuum, fresh air enters the tank through the vacuum valve while the pressure valve stays closed.
The international standard for the positive pressure opening is +3 inches of water column (+750Pa), and the activation negative pressure is -8 inches of water column (-2000Pa). For the Chinese domestic market standard, the positive pressure opening is +9 inches of water column (+3000Pa), and the activation negative pressure is -8 inches of water column (-2000Pa).
Installation Instructions:
Before installing the PV vent, it is recommended to cycle the poppet up and down. This ensures free operation of the poppet if the valve has had an extended shelf life.
An inlet screen is now included with the Vacuum Pressure Vent Valve to avoid ingestion of particles from the riser pipe that could cause the valve poppet not to seal properly.
These vacuum pressure vent valves are used in gas stations or oil storage depots. The vent valve typically consists of two parts: a pressure valve and a vacuum valve designed to be installed inside. It is usually installed at a height of approximately 4.5 meters on the vent pipe of the oil storage tank to maintain the tank's tightness under normal circumstances. They protect tanks from excessive over- or under-pressure. The vent cap and internal wire screen are designed to protect the tank vent lines against intrusion and blockage from water, debris, or insects. A normally closed poppet in the valve opens at a predetermined pressure or vacuum setting to allow the tank to vent.

HYZQF-50FA Vacuum Pressure Vent Valve With Flame Arrestor
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Technique Specification: Body: Aluminum Cap: Aluminum Screen: 40 Mesh Stainless steel mesh Gasket: Buna-N or Viton for option Temperature Range:-20~+50℃ Positive:+3 inches of water column for the international market, + 9 inches of water column for the domestic market Negative: -8 inches of water column Flame Arrestor Body: Cast Aluminum (Flange Connection) Inner Arrestor Material: Foldable Aluminum Alloy
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Order Specifications:
| Model |
Connection Method |
| HYZQF-50FA |
2-inch Aluminum Flange |
| HYZQF-65FA |
2.5-inch Aluminum Flange |
| HYZQF-80FA |
3-inch Aluminum Flange |
Standard of connecting flange can be produced according to the client’s detailed requirements.
Important Note: These vents should not be used on an underground storage tank (UST) with a throughput of 100000 gallons or more per month.
Features:
It reduces oil evaporation losses to a certain extent. When necessary, it can automatically open and adjust to maintain a balanced pressure inside and outside the tank, serving a safety function for the tank.
When the vapor pressure in the tank exceeds the allowable pressure, oil vapor is released through the pressure valve, while the vacuum valve remains closed.
When the vapor pressure in the tank is lower than the allowable vacuum, fresh air enters the tank through the vacuum valve while the pressure valve stays closed.
The international standard for the positive pressure opening is +3 inches of water column (+750Pa), and the activation negative pressure is -8 inches of water column (-2000Pa). For the Chinese domestic market standard, the positive pressure opening is +9 inches of water column (+3000Pa), and the activation negative pressure is -8 inches of water column (-2000Pa).
Installation Instructions:
Before installing the PV vent, it is recommended to cycle the poppet up and down. This ensures free operation of the poppet if the valve has had an extended shelf life.
An inlet screen is now included with the Vacuum Pressure Vent Valve to avoid ingestion of particles from the riser pipe that could cause the valve poppet not to seal properly.