Friday, July 17, 2015

AN OVERVIEW OF AIR VALVES

Air Valves
The air is settled at the start-ups of pipelines which is exhausted during filling operation. Sometimes, they can easily find the key holes to make their way into the pipelines. Over the course of time the air pockets wreak the pipeline system, thereby resulting in major spills or even flooding. To overcome this problem air valves are installed at high elevations of pipeline systems.

These air valves effectively release the accumulated air from pressurized pipelines thereby preventing bubble formation along the water transmission lines.

There are basically two types of Air valves available in the market, which serve number of functions in pipeline systems. Their overall purpose is to regulate air pressure and control the liquid conveyance system. However, it is important to have detailed knowledge about the functioning and limitations of each before installing them in the pipeline system.

Air Release Valves

The Air Release Valves are widely used air valves as they have the ability to release little air pressure continuously during pipeline operation. This helps in preventing the vacuum formation during pipeline's filling and draining operation.

However, the gradual release of air pressure can decrease water flow which in turn increases the power consumption; unnoticeable at first. If the situation continues it will lead to unexplained pipeline rupture. To prevent the pipeline from bursting air valve has a float to sense the presence of air and linkage mechanism. Under the full pipeline pressure the float mechanism gets benefit from the float thereby opening the orifice and vice-versa.

Air/Vacuum Valves

The smooth functioning of pipeline system requires little internal pressure. If the internal pressure drops below a certain atmospheric pressure, the pipeline will experience an excessive deflection force which will lead to collapse of pipeline.

An air/vacuum valve is installed downstream of pumps, generally at high points to regulate the release of large volumes of air during start-up of pumps and filling of pipeline. Air/vacuum valves are installed for more effective operations as they have high capacity of releasing and admitting air into pipeline systems. These valves are also designed to provide tight seal at low internal pressure. Hence, they are used to prevent the vacuum formation which further contributes to improvement of efficiency of the pipeline systems.

The bottom Line

The most effective way of protecting pipeline from these negative effects is to install air valves of right configuration. Air Valves are available in several configurations and different materials. Depending on the application, length of pipeline and environmental conditions, these air valves are installed to make the most out of pipeline systems.

However, in most pipelines combination of valves are used because they provide multiple air valves functions. The omission or fault in field installation will overlook by other air valve thereby not leaving pipeline unprotected.