Automatic control issues of booster pumps
Thread Content
The workshop is equipped with a tap water pressure booster pump that is connected to a system controller. The electrical contact pressure gauge has a set point of 5 kilograms at the upper limit and 3 kilograms at the lower limit; the pump starts when the pressure falls below 3 kilograms and stops when it exceeds 5 kilograms. Why does it start every two seconds even with a small amount of water flow? The frequent starting must have an impact on the pump’s service life. The pipeline pressure test was successful; there are no leaks anywhere. Then why can’t the pressure be maintained? Let’s see if anyone here has experience in this area; could you share it? Thank you!
Because liquid (water) is incompressible, if there is a DN200 pipe 500 meters long at the pump outlet and the pressure there is 5 kilograms, then even when someone uses just a cup of water – 260 ml – or washes their hands, the pressure at the pump outlet will drop below 3 kilograms, causing the pump to start operating. The solution is to install a vertical container at the pump outlet that can withstand a pressure of 7 kilograms; this container should be equipped with a safety valve rated for 6 kilograms – it’s better to have two such valves, one as a backup, and they need to be checked regularly. For example, the container could have a diameter of 1 meter and a height of 2 meters, with water entering at the middle and lower sections and exiting from the lowest part. The liquid level should be maintained at 600 mm at the lowest point, while the upper part should be filled with air. By taking advantage of the fact that air can be compressed, the larger the volume of air in the upper part, the longer the time it takes for the pump to start operating.