Air Valves Introduction
The A.R.I. line of automatic air release valves is based on the rolling seal technology. The self-cleaning feature of the rolling seal mechanism greatly reduces the possibility of clogging, leaking and the adhesion of suspended particles to the rolling seal surface. The valve body and interior components are made of corrosion-resistant materials. This ensures years of corrosion and maintenance-free operation, even under extreme environmental conditions.
The A.R.I. line of industrial products also includes a wide variety of air & vacuum and combination air valves. They are made of the same quality materials as the automatic air release valves and provide the same level of quality and assurances.
These valves are offered in dimensions of 1/2” to 1” (automatic air release valves) and 1” to 12”(air & vacuum and combination air valves). They provide solutions for various applications in all industrial fields. These products are lightweight, have a compact profile and are offered at competitive prices.
Air in Industrial Liquid Transmission System
The quantity of air must be controlled in industrial liquid transmission systems. The presence of air/gas bubbles and pockets can be beneficial or detrimental to the transmission system under different conditions. The absence of air, such as exist under vacuum conditions, prevents suitable protection for the transmission systems.
Damage caused by the presence of air in the system
- Air blockage in the line causes unstable flow of the liquid and, in extreme circumstances, a total stoppage of flow.
- High head losses, resulting in large energy losses.
- The impact of surge, as a result of the presence of air in the system, can cause damage to pipes, accessories and connectors.
- Erroneous readings of water meters and automatic metering valves.
- Extensive damage to impeller systems in water meters, flow regulators, sprinklers and sprayers.
- Pitting and increased corrosion in metal components of the systems.
- Safety risks to operators increase due to the possibility of high energy bursts in locations where there are concentrations of compressed air.
Damage caused by the absence of air in the system
Vacuum enhanced problems and damages:
- Suction of mud and dirt through faulty connections, cracks in pipes and accessories, etc.
- Suction of seals and gaskets, in–line fittings, and other internal accessories of pipes.
- Uncontrolled suction of injected chemicals into the system.
- Pipe or accessory collapse.
- In some cases, the absence of an air cushion can increase the damages of surge and slam phenomena.
Using A.R.I Air Valves to Control Air and Prevent Damage
There are three principal types of air valves used in industrial applications:
- Air & Vacuum Valves
- Automatic Air Release Valves
- Combination (double orifice) Air Valves
Air & vacuum valves automatically discharge air at High-Flow rates during filling of the system and admit air at High-Flow rates during draining, at water column separation, and in cases of down surge in the system.
Air & vacuum valves are known also as: large orifice air valves, vacuum breakers, low-pressure air valves and air vacuum valves.
Automatic air release valves release air entrapped in the system while under pressure. The air release flow rates of the automatic air release valves are lower than those of the air & vacuum valves. They are also known as: air release valves and small orifice air valves.
Combination air valves include both air & vacuum and automatic air release components in one unit. They perform both functions:
They discharge air at High-Flow rates during filling of the system and admit air at High-Flow rates at system drainage or water
column separation, AND
They release entrapped air while the system is under pressure.
Combination air valves are also known as double orifice air valves.
Characteristics of Industrial Air Valves
1) Resistant to Corrosion and Hostile Environments:
- The materials used to manufacture the outer shell and internal parts are adapted for a wide range of industrial fluids.The product must be able to withstand extreme environmental conditions such as a marine atmosphere and wide ranges of temperatures (from 0° C. to 150° C.)
- All these features should not weaken the mechanical strength of the materials. The products should meet the required pressure standards as dictated by the various industrial processes.
2) Maintain the High Performance Level of the Standard A.R.I. Air Valve:
- There are two air valves groups:
- Air valves used with clear liquids
- Air valves used with liquids containing suspended solids.
- These industrial products maintain the original performance levels of the standard A.R.I. air valves even though they have been adapted for industrial applications. These include changes in the float assembly and sealing mechanism due to the change in specific gravity of the industrial liquids and the stricter safety requirements.
3) Flexibility in Choosing Air Valves Based on Industrial System Requirements:
- Product suitability is determined by chemical analysis of the liquid.
- Product suitability is determined by the pipeline standards as well as the accompanying accessories.
- Most existing air valves have mechanisms to prevent hydraulic surges. (NON- SLAM additions)
- The Application Engineering Departments of A.R.I. performs various hydraulic analyses of the systems:
- Protection against column separation of the liquid in the pipeline and the ensuing rise in negative pressure that results from traumatic events to the steady flow regime by performing a pipeline analysis using the ARIavCAD software program.
- Protection against transient episodes (UP & DOWN SURGES) by performing a pipeline analysis using the KYPipe surge software program.
4) Operational Safety:
- The air valves are designed to seal tightly and prevent the leaking of dangerous fluid which could be harmful to humans and pollute the environment.
- Optional vent/drain pipes can easily be attached to the discharge orifice if needed.
- The air valves are built to remain intact and function over time in aggressive conditions.
Installation and Location
It is highly recommended that a basic review be made before selecting the appropriate air valves and determining their sizes and locations:
- The chemical composition of the liquid that passes through them.
- The possibility of extreme pressure changes such as up-surges and down-surges.
- Analysis using ARIavCAD software for efficient design of the system (software available from A.R.I).
Typical installation locations:
- In pump stations.
- At locations where pressure drops.
- At peaks along the line.
- At locations of large convex slope changes.
- Along line segments without air valves.
- Near isolating valves on the line.
- On filter setups.
- Before flow meters and automatic devices.
- At line ends.