The ALPER Model Atmospheric Valve from Valfonta is a high-precision device designed to protect tanks and sealed vessels against damage from overpressure or implosion caused by vacuum. Its function is to allow controlled air entry or exit to balance the internal pressure with the atmospheric pressure.
It is especially designed to work in very small pressure ranges (low pressures). It incorporates a double spring system that allows for independent adjustment of both the vacuum breaking pressure (negative pressure) and the relief pressure (positive pressure). In addition, the exhaust output is protected by a stainless steel mesh that prevents impurities or insects from entering the equipment.
- Regulation Type:
- Single Regulation: For vacuum control only (Fig. 334/335/350/351).
- Double Regulation: For simultaneous control of Pressure and Vacuum (Fig. 336/337/352/353).
- Pressure Ranges:
- Positive Pressure (Relief): From +0.080 to +8 Bar.
- Negative Pressure (Vacuum): From -0.050 to -0.650 Bar.
- Opening: Progressive.
- Materials:
- Body (Bell/Foot): Bronze RG5 or Stainless Steel AISI 316L (CF-8M).
- Disc: Bronze RG5 or Stainless Steel AISI 316L.
- Maximum Temperature:
- Inox Version: Up to 280 °C.
- Bronze Version: Up to 240 °C (depending on basic safety valve model, but for atmospheric it is usually lower).
- Connections:
- Inlet: BSP Male Thread or DIN Flange.
- Outlet: BSP Female Thread (ducted exhaust at 90°).
- Stainless Steel Series (AISI 316L / CF-8M): Ideal for sanitary, chemical, or corrosive environments. Natural/Polished Finish.
- Single Regulation (Vacuum): Fig. 334 (Threaded) / Fig. 335 (Flanged).
- Double Regulation (P/V): Fig. 336 (Threaded) / Fig. 337 (Flanged).
- Bronze Series (RG5): Ideal for general applications. Nickel Plated Finish.
- Single Regulation (Vacuum): Fig. 350 (Threaded) / Fig. 351 (Flanged).
- Double Regulation (P/V): Fig. 352 (Threaded) / Fig. 353 (Flanged).
The valve acts as an intelligent vent for the tank:
- Vacuum Break (Air Inlet): When the tank is emptied or the fluid cools, the internal pressure drops. If this depression exceeds the vacuum spring setting, the valve opens inward, allowing atmospheric air to enter and preventing the tank from collapsing (implosion).
- Pressure Relief (Air Outlet): (Double regulation models only). When the tank is filled or the fluid is heated, the internal pressure increases. If it exceeds the pressure spring setting, the valve opens outward, releasing excess air/gas to prevent overpressure.
- Position: It must be installed vertically at the top of the tank or piping.
- Protection: Periodically check that the outlet protection mesh is clean and unobstructed to guarantee the necessary air flow.
- Connections: Available from 1/2" up to 4" (see dimension table by figure).
- Options: On request, it can be supplied with NPT connections, ANSI flanges or special materials for the spring (Stainless steel 302/316).
