Pump suction port is generally larger than the outlet, because the suction port for low pressure, water density is small flow rate is slow, in order to meet the water supply balance requirements and maintain a certain inlet pressure head, to prevent cavitation, generally large; outlet flow rate is fast, the same pipe diameter flow, so the decision to connect the suction port to be larger than the outlet of the water. The mouth diameter of large suction resistance is small, in favor of the pump suction medium, the outlet diameter is small, in favor of the pump's export pressure to maintain stability. To ensure the stability of the LiBr absorption unit.

For most centrifugal pumps used in Hope Deepblue LiBr absorption unit, import and export pipeline diameter increase is to reduce the fluid flow rate in the pipeline to reduce the pipeline resistance drop to reduce the power consumption of the pump, but increase the diameter of the pipeline is to increase the cost of pipeline investment at the expense of, so that for the pump outlet for a long distance of the pipeline can be considered to appropriately increase the diameter of the pipeline in order to reduce the resistance drop, and for short distances can not be considered.