Patent ID: 8623465

Claim:
A coating membrane forming method for forming a coating membrane on an object to be coated, the method comprising the steps of: setting the object to be coated for forming a coating membrane thereon in a dipping tank; sending an application liquid for forming the coating membrane into the dipping tank to raise a liquid level of application liquid in the dipping tank until a top of a region for forming the coating membrane on the object to be coated is immersed in the application liquid; and thereafter lowering the liquid level of the application liquid in the dipping tank by discharging the application liquid outside the dipping tank; wherein during immersion a pressurized gas is supplied in a space defined by an inner peripheral face of the dipping tank, an outer peripheral face of the object to be coated, and a respective sealing member, which respectively define a seal between a top and a bottom of the outer peripheral face of the object to be coated and the inner peripheral face of the dipping tank, so that the pressurized gas flows into pores of the object to be coated to pressurize insides of the pores, and wherein the object to be coated is a porous body.