If the transformer oil is used as the operating liquid, these pumps are called oil ring vacuum pump and the suction pressure can reach 6.7mbar (abs) i. So the oil ring vacuum pumps can replace the reciprocated vacuum pumps completely. When the liquid ring vacuum pumps work under the condition near the limited vacuum for a long time, it is necessary to couple with the cavitation protection pipe in order to get rid of the screaming and protect the pump. When the compressors work, the maximum pressure is 0.26MPa(abs). And the higher of discharge pressure, the larger of the power of the compressors.So it is necessary that the data of the discharge pressure is provided to choose the proper motor. 2BV2-Ex, 2BV6 series water ring vacuum pumps and compressors are mainly used for pumping the explosive gases or work in the flammable and explosive environment. The technical parameter of each type is the same as the corresponding type of the 2BV2 or 2BV5 series. 2BV series stainless steel pumps can be used under the conditions with higher requirements for the corrosive-proof or the lustration. According to the working situation, the material of all the parts where the liquid flows i. Pump casing, pump cover, port plate, impellerare made of various stainless steel as bellow. The material of the shaft is 2Cr13 or 0Cr18Ni12Mo2Ti.
The mechanical seals are used the John Crane products and the seals material is optional for FPM or PTFE.