Behind the success of any irrigation scheme, large or small, is the ability to maintain a constant water pressure. Both low and high pressure systems can be severely compromised by air in the pipelines or a vacuum behind water. To mitigate these problems RX Plastics offer pressure release valves for your irrigation system.
What happens when air gets trapped in pipe?
At some point most irrigation systems will experience some trapping of air, but low velocity systems are most susceptible to air getting trapped in a pipeline. As water flow drops more air is allowed into the pipe. The build up of air pressure means that water has to go faster across the section of pipe and pressure loss occurs.
Another symptom of trapped air is water hammer. This knocking of the pipeline is a result of the converted energy from the build-up pressure in the system, and tends to be exacerbated by fast closing valves.
Releasing the pressure
The simple unit will allow trapped under low pressure to escape, and as the water pressure increases the valve closes shut. With this type of system, the pressure release valve is usually place at the highest point along the pipeline.
The double effect version of the pressure relief valve will allow the valve to open if the air bubble is under pressure, effectively ‘burping’ the system at that point. This is done via a simple but effective float valve in the chamber of the valve.
A number of these valves can be installed along the pipeline. spaced 500-600m apart, and these will release air along these points.
RX Plastics offer these pressure relief valves in a number of sizes, depending on pipeline, up to 2in in diameter. No matter what size your irrigation system, there is a pressure release valve to suit.
If a pump is switched off on a line, there is a high chance that a vacuum will occur behind the flowing water. In instances like these it is essential to have air enter the pipe. If no air is behind the water the vacuum could see pipelines with thinner walls collapse under the negative pressure.
Pressure release valves are therefore essential on pumped systems, ensuring any vacuum is removed and appropriate pressure is maintained. Once water enters the system once more, the valve will then release the air in the pipe, ensuring a consistent water pressure.
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