The method for improving the cavitation margin of the device is:
1. Vertical pump, the first stage impeller at the bottom.
2. To reduce the pump mounting height, on the land when the pump is installed in the ground below, on the ship can be in the bottom of the design of caisson to the pump is installed in the caisson.
3. Raise the height of the suction container or increase the pressure of the suction surface.
4. Strengthen the suction vessel and the suction line and cold preservation, to prevent the introduction of heat to the surrounding, increasing Yong Ding liquefied gas temperature, and increase the vapor pressure of the liquefied gas, reducing device of NPSH.
To improve the device's cavitation is often not economical, so the fundamental measure is to improve the pump cavitation performance, in order to reduce the side of the side of the cavitation, the main method used in the low temperature pump is:
1. According to the requirements of the cavitation performance of the special design of the impeller. In order to improve the pump into the flow at 1:1, even if the speed is very low (less than 20) of the impeller with blade inlet distortion.
2. Induction wheel in front of the first stage impeller. Inducer is a kind of axial flow impeller. In the beginning of cavitation induced Luo wheel cloud. Induced itself round the cavitation performance can be designed very high, through the induction of round liquid adds energy ensure the liquid flow cavitation in the pump impeller, because the liquefied gas on the cavitation effect is smaller than water, not easy to cause erosion damage, so in cryogenic pumps use inducer is very appropriate.
3. The first stage impeller with super cavitation. Practice has proved that the use of ultra cavitation impeller can be widely adapted to the situation of different liquid flow, it is a recent development of new technology.
