Freely dissolved air exists in all fluid transmission systems.

The principal sources for this air are:

1. Incomplete filling of the line – which leaves air pockets in high places and in different accessories.
2. Air dissolved in the fluid that is released when the pressure drops and/or there is a rise in temperature.
3. Vortexes in the fluid, at the points from where it is pumped, introduce air into the system.
4. Air is sucked into the system through openings and accessories.

The lack of control over the air present in a fluid system can result in damage:

1. If destructive vacuum conditions are created.
2. The presence of air can have a detrimental effect on system drainage efficiency.
3. Air pockets in the system cause reduced     sectional cross flow, higher energy losses, tremors in the system and in extreme conditions; the entire stoppage of flow.
4. High pressure surge.
5. Metal parts in the system and system accessories corrode at higher rates.
6. Lower pumping efficiency.
7. Physical risk – when large volumes of air under pressure are released at high velocities.
8. Inaccuracies in the measurement of fluid volumes.
9. Accelerated wear of moving parts and flow gauges.
10. Cavitation damage.

Control of Air in Wastewater Systems Using A.R.I. Air Valves

There are three main types of air valves installed in wastewater supply systems: air & vacuum, automatic air release and combination (double) valves.

Air & Vacuum valves discharge large quantities of air from non-pressurized pipes and are used mainly when filling a line. Air & vacuum valves also make it possible to admit large quantities of air when lines are drained and when the pressure drops suddenly. Air & vacuum valves are also known as: kinetic valves; large orifice air valves, vacuum breakers, low-pressure air valves and air-relief valves.

Automatic air release valves continuously release relatively small quantities of air from a pressurized line. The automatic air release valve is also known as a small orifice air valve and as a pressure air valve.

Combination air valves fulfill the tasks required of both types of valve – air & vacuum and automatic. In other words – they discharge or intake large volumes of air when filling or emptying a system and continuously release small volumes air when the line is pressurized.

Combination air valves are also known as double orifice air valves.

 Download Installation Guide