Air relief valves

Problems caused by the presence of air in networks may be solved by fitting suitable equipment.
BELGICAST can supply a wide range of devices with the highest quality to allow you to prevent faults in your system and optimize its performance. You can choose the most suitable products to regulate the entry and escape of air from networks and protect them from problems such as:
· Head losses
· Pressure variations
· Water hammer
· Pipe breakage

DOUBLE EFFECT AIR RELIEF VALVE "VANNAIR" for drinking water, fire protecting and irrigation network
Double air valve, providing three functions:
- High flow rate air discharge capacity for pipe-filling operation,
- High flow rate air inlet for pipe drainage operation and in case of pipe burst,
- Continuous evacuation of air under normal working conditions (small orifice function).
"Vannair" double orifice air valves are built according to an original compact design, with or without isolating valve. They are made of two floats mechanically free, operating in a single chamber body, aerodynamically shaped. One float is a ball fully covered with elastomer, the other is a disc in which are inserted two O-rings in a concentric way. Movements of the floats are guided in up and down direction. The floating ball ensures the shut-off of the small orifice, whereas the floating disc ensures the shut-off of the bonnet large orifices. These large orifices have a surface area calculated to insure free passage of the required quantities of air. An exhaust controller placed in the middle of the bonnet allows to check if the small orifice is not filled up (device similar to the one use on single orifice air valve). A cover protects the bonnet large orifices against dirt, and allows to direct air exhaust in downward direction. The original concept ensures a safety operation without problems.
OPERATION
During pipe filling, air goes out freely at high flow rate through the bonnet large orifices. When the inlet of the valve fills gradually, with water replacing the air, the floating ball and disc rise and come into contact with the small and large orifices, shutting them off. During pipe drainage operation, or in case of pipe burst, the float-disc drops, thus opening the orifices and allowing air in-flow at large rate. Types V1000 and V2000 are delivered in standard with reversible disc (patented). This original concept allows to choose to close under air flow rate or water flow rate (see graphic below for flow rate values in  order to get closing under air flow conditions).
closing under air flow rate > disc side with groove on the top.
closing under water flow rate > flat disc side on the top.
Designed for pipeline pressure PN 16/25.

SINGLE ORIFICE AIR VALVE for drinking water, fire protection and irrigation network
OPERATION
When there is no air, the force of water on the float, assisted by the internal pressure, closes the evacuation orifice.
If an air pockets fills the air valve, the weight of the float exceeds the effect of the internal pressure and the float moves downwards to open the orifice. When water comes, the assembly closes. The built-stopcock allows the device to be isolated for checking and maintenance.
EXHAUST CONTROLLER
Model specially design for the safety and simplicity of its operation. This controller is composed of a fixed body .
screwed in the bonnet and bearing inside a drilled thrust ring, as well as a screw plunger , through which the exit orifice passes. In the operating position , the thrust ring extends beyond the orifice and thus is in direct contact with the float. In the checking position , the seat moves back inside the drilled ring. The float is stopped by this ring, against which it presses, thus clearing the orifice, without any risk of damage to the elastomer covering of the float. A leak is therefore created, which allows the operating states of the device.
Pipeline pressure PN 16/25/40.

ANTI-WATER HAMMER RELIEF VALVE DJET for drinking water, fir protection and irrigation network.
FEATURES: The BELGICAST BV-05-62 relief valve protects installations against excess pressures and water hammer. It immediately expels excess water as the pressure comes within a preset range, damping the impact of water hammer on the network and preventing pipe breakage or other adverse consequences.
· Strong construction enables it to work with high pressures.
· Complete anti-corrosion epoxy coating (RAL 5015).
· Very low inertia and rapid response to excess pressures.
· Fitted with a pressure gauge to control network pressure.
· Four models available: ND-50/65 and ND-100 (direct action), and ND-150 and ND-200 (piloted).
· NP - 16/25.
OPERATION: The  relief valve is equipped with a spring-operated trigger system which lets the valve open as soon as the set pressure is reached (max. 2 bar excess pressure). When the effect of pressure on the valve seal exceeds the force of the spring, the valve opens instantaneously to allow discharge in proportion to the excess pressure. As soon as the irregularity disappears the valve progressively returns to the "closed" position. The spring-operated trigger system can be adjusted on the spot ± 1 bar by means of a manual key on the top of the valve. For adjustments  bigger than ± 1 bar it should be verified that it fits the pressure range admited by the
spring: The valves are supplied with 5 types of springs for
following pressure range:
DN-100: 1 to 5 / 5 to 7 / 7 to 16 / 16 to 25 / bar
DN-50 / 65 / 150 / 200: 1 to 5 / 5 to 10 / 10 to 16 / 16 to 25 bar
The adjustment device is protected against humidity and water discharge by an EPDM gasket.