Water Ring Vacuum Pump to a Certain Load
In summer high temperature season of water ring vacuum pump, when the unit reaches a certain load and the condenser pressure rises to 12.2 kPa, the air intake solenoid valve of the front exhauster interlocks and closes, so that the front exhauster bypass diaphragm valve opens automatically, and the water ring vacuum pump pumps vacuum directly to the condenser through the inlet isolation valve of the vacuum pump group and the front exhauster bypass diaphragm valve. With the increase of steam temperature, the water in the vacuum pump begins to vaporize, and the noise and vibration of the instantaneous rupture of bubbles in the pump occur. The vacuum pump is tested. The parameters of the vacuum pump before and after cavitation are shown in Table 1. In order to protect equipment and maintain unit operation, frequent switching of vacuum pumps and reducing unit output have to be adopted to maintain unit operation.
Water ring vacuum pump has the advantage of high efficiency in suction when it operates in low vacuum range. Water ring vacuum pump uses water as working fluid, so the characteristics of the pump are affected by the working water temperature. In order to maintain the suction capacity, the working water of the water ring vacuum pump must maintain a certain degree of supercooling. When the working water temperature in the pump is higher than the saturation temperature under the corresponding pressure, the working water will vaporize, which will cause the cavitation of the vacuum pump. The limit value of the vacuum pumping is the saturation pressure corresponding to the temperature. In the operation of water-ring vacuum pump, impeller and water ring constantly impact and friction, while the extracted vapor-gas mixture liquid continuously heates the working water, so that the temperature of water ring keeps rising. In order to ensure the normal operation of the vacuum pump, the working water must be continuously cooled. Therefore, the cooling water temperature of working water is the key point of the problem.
