Patent ID: 8794257

Claim:
A liquid storage device, comprising: a liquid storage tank; a liquid intake tube, a liquid discharge tube and a gas discharge tube provided with a check valve all connected with the liquid storage tank; and a gas compensating tube connected with the liquid storage tank; wherein the gas compensating tube comprises a gas storage tank and a differential pressure mechanism having one end connected with the liquid storage tank and the other end connected with the gas storage tank for controlling the connection or disconnection between the liquid storage tank and the gas storage tank according to the pressure difference between pressure in the liquid storage tank which is determined by a liquid level therein and pressure in the gas storage tank; wherein, when the liquid level in the liquid storage tank rises as liquid being supplied through the liquid intake tube and gas pressure in the liquid storage tank increase and exceeds opening pressure of the check valve, the check valve opens to allow the gas in the liquid storage tank to flow out through the gas discharge tube; when the liquid in the liquid storage tank is discharged through the liquid discharge tube and the pressure difference between the pressure in the gas storage tank and the pressure in the liquid storage tank exceeds a first preset value, the differential pressure mechanism opens automatically to connect the liquid storage tank and the gas storage tank; when the pressure difference between the pressure in the gas storage tank and that in the liquid storage tank is below a second preset value, the differential pressure mechanism closes automatically to disconnect the liquid storage tank and the gas storage tank.