Automatic constant voltage metering water injection apparatus

The utility model relates to an automatic constant-pressure affusion measuring device comprising a control box, an electromotor electrically connected with the control box, a water pump coaxial with the electromotor as well as a water inlet pipe and a water outlet pipe connected with the inlet and the outlet of the water pump, wherein the water inlet pipe is provided with a flow meter; the water outlet end of the water outlet pipe is provided with a drain valve; the water outlet pipe of the water pump is provided with a pressure water tank, a flow switch and a pressure switch; and the flow switch and the pressure switch are respectively electrically connected with the control box. The utility model is simple in structure and reasonable in design, realizes the automatic start and stop of the water pump in the affusion process, greatly improves the work efficiency, saves the expense, can also ensure that water smoothly flows through the flow meter and is poured in a grotto under the condition of constant pressu