Product details

A pressure vessel is designed to store a volume of pressurised water, reducing the number of times a pump needs to operate, reducing wear on the pump and running costs. Pressure vessels are manufactured in a number of sizes.

Which size pressure vessel?
Electric pumps should not be operated more the 20 times per our, otherwise they will wear out prematurely. The vessel is sized to ensure that the pump does not come on too frequently. Smaller 20 litre pressure vessels are typically found on mist propagation systems where there is a frequent demand for small amounts of water. A mist propagating controller will operate up to 30 times per hour in hot weather, but the volume of water used for each cycle is quite small, so a 20-25 litre pressure vessel will be suitable. A smaller model can also be used where the pipework has small leaks, perhaps from a system that is getting quite old. Leaks tend to burn out an auto-start pump as the pump is constantly cycling on and then off. The vessel will increase the interval between pump starts and also increase the run time of the pump as it has to recharge a larger volume of water.

How does a pressure vessel work?
Inside the steel outer body of the pressurised vessel is a membrane that separates the water from the surrounding air inside the cylinder. As the pump operates it pumps water under presser into the inside of the membrane, compressing the air that is between the membrane and the steel cylinder. Once the pump has stopped, as one-way valve prevents water from flowing backwards through the pump. When there is a demand for water, for example a tap is opened, the water leaves the membrane and the air around the outside of the membrane expands, maintaining the pressure. Once the reservoir of water inside the membrane is used up, the pressure will drop and the pump will be restarted via a pressure switch.

Technical specification:
Pressure rating: 10 bar
Inlet/outlet fitting: 1″ BSPM thread.