For different types of water ring vacuum pumps, the suction volume flow curve is related to the suction volume cavity and the size of suction port: when the suction port is small and the suction volume cavity is relatively large, the suction volume flow increases with the increase of suction pressure; When the suction volume cavity is relatively small, with the increase of suction pressure, the suction volume flow will be full of the whole cavity when the suction volume flow increases to a certain value. When the suction port is large and the suction volume cavity is relatively small, the speed of air filling the cavity is faster to keep the suction volume flow unchanged. When the inspiratory pressure increases to a certain value, the inspiratory pressure in the volume cavity will increase and the inspiratory volume flow will decrease due to the constant inspiratory volume cavity and the continuous increase of the maximum flow rate of the inspiratory gas.
When the water ring pump is running, its suction temperature, working water temperature and suction cavity remain unchanged. According to the gas state equation PV = MKT, the suction mass flow is basically proportional to the suction pressure, that is, P1 / P'1 ≈ M1 / m'1
According to the relationship between inspiratory mass flow and inspiratory volume flow, with the increase of inspiratory pressure, inspiratory volume flow begins to increase, and then slowly decreases.