The utility model discloses a metering device which comprises a shell, a heat preservation cavity is formed in the shell, a
stock solution tank is erected in the heat preservation cavity, a
metering pump is further fixedly arranged on the bottom face of the heat preservation cavity, the metering device further comprises a discharging faucet, and an outlet of the
metering pump is connected into the discharging faucet through a second discharging
pipe. Due to the fact that the
backflow pipe communicated with the interior of the
stock solution tank is arranged in the discharging faucet, when the valve in the discharging faucet is in the
closed state, if the motor is powered on, liquid in the
stock solution tank can keep flowing, the phenomena of layering,
sedimentation and the like are avoided, and the discharging faucet can be used for discharging the stock solution in the stock solution tank. The stability of the gushing stock solution when the valve is opened is ensured; the stock solution tank is heated through the heating sleeve, so that the stock solution can be kept at a certain temperature, in addition, heat preservation is achieved through the heat preservation layer and the ring cover on the shell, energy waste is reduced, and the stock solution is prevented from being cooled too fast in the discharging
pipe.