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Air Release Valve Menu

Introduction

This range of air valve has been designed for use in long pipe lines where it is essentials to exhaust 
or admit air during filling or draining of the line. and to bleed off automatically  and build up of accumulated air during normal flow. Self acting air valves should be installed at selected points on 
the line of mains.

The air valve has been manufactured to two type of orifice to suit the different of amount of air to 
be admit. It is single small/large orifice  and double orifice.

Single small orifice   -    Automatically discharge accumulated air during pipeline 
                                         flow.

Single large orifice    -    Automatically exhaust air when filling or allows the 
                                          admission of air during admission of a pipeline.

Double orifice          -      A combination of a small and large orifice.

Operation

Small orifice

Normally the valve is sealed by the upthrust of a submerged rubber ball. Any build up of accumulated air in the valve chamber will depress the water level sufficiently. Causing the ball to drop away from the orifice seat and allowing the air to escape.

Large orifice

Under normal operation condition the ball is held in contact with the orifice seat by the water pressure in the main and only leaves the orifice seat when the pressure in the valve drops to atmospheric. However if high air velocity is likely to occur the Aerodynamic large orifice is recommended.

Aerodynamic

Developed to overcome the problem of premature closing due to a high discharge velocity which can occur during filling of the pipeline.

Economics

To ensure that a pumping system will operate in the most efficient manner, care must be taken to ensure that trapped or entrained air is not robbing the system of the efficiency that the designer originally intended.

Air entry

There are numerous ways in which air can enter a pipeline, a few common ways are :-

1. Air that is in the line before the line is filled and not completely purged.
2. Well pump installations without air release valve can on start up add considerable air to the pipeline.
3. Air may be drawn in at intakes. For example by the vortex action at a pump suction.
4. Air may be drawn into the line at leaking joints or gland.
5. Air in solution is released at a higher point in the line or at points of pressure reduction. Such as throttled valves or other restriction.

Installation

Once in the system, air will tend to collect at summit in the pipeline and points where the pipe slope changes. Just a important as the proper selection of air release valves is the proper location and installation. Air pockets are generally found just downstream of the area where they are first suspected due to the velocity of the fluid. As a general rule required location of air release valves may be seen by referring to the drawing. A careful study will show that there is an air release valve at change in the pipeline slope with the exception of the extreme low points.

Applications

Pressure Rating

Minimum pressure for tight float seal : 6m head
flange drilling to BS 4504 TABLE 16/11

Nominal diameter

Weight

Small and large orifice air valve with integral isolating valve

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