Abstract: It is an object of the present invention to provide a method of calibrating a pressure measurement unit for measuring the pressure inside an extracorporeal circuit while avoiding contact with the air, in which, even when the connection between an air chamber of the pressure measurement unit and a pressure measurement means is disengaged accidentally or intentionally after the operation of changing the pressure inside the extracorporeal circuit from the initial pressure, the pressure measurement unit can be reconnected and the pressure inside the extracorporeal circuit can be measured stably. After closing the extracorporeal circuit in such a way that the pressure measurement unit and a pressure adjusting means are contained in the closed section, the pressure inside the liquid chamber is adjusted to a predetermined pressure using a pressure adjusting pump, and then the pressure measurement means and the air chamber of the pressure measurement unit are connected to each other.

Abstract: It is an object of the present invention to provide a method of calibrating a pressure measurement unit for measuring the pressure inside an extracorporeal circuit while avoiding contact with the air, in which, even when the connection between an air chamber of the pressure measurement unit and a pressure measurement means is disengaged accidentally or intentionally after the operation of changing the pressure inside the extracorporeal circuit from the initial pressure, the pressure measurement unit can be reconnected and the pressure inside the extracorporeal circuit can be measured stably. After closing the extracorporeal circuit in such a way that the pressure measurement unit and a pressure adjusting means are contained in the closed section, the pressure inside the liquid chamber is adjusted to a predetermined pressure using a pressure adjusting pump, and then the pressure measurement means and the air chamber of the pressure measurement unit are connected to each other.

Abstract: A pressure sensor for an extracorporeal circulating circuit includes a liquid chamber, a pressure measuring means, and a liquid flow path. The liquid chamber includes a reference surface not deformed by a pressure in the extracorporeal circulating circuit, a deforming surface disposed separated from the reference surface and deformed at least partially by a pressure in the extracorporeal circulating circuit, a first connection surface that joins the deforming surface with the reference surface to form a closed liquid-tight space inside them and is not deformed by a pressure in the extracorporeal circulating circuit, a liquid inflowing port provided in the side surface of the first connection surface, and a liquid outflowing port disposed away by ½ to less than one round from the inflowing port in the flowing direction of liquid introduced along the inner periphery of the side surface of the first connection surface.

Abstract: A pressure sensor for an extracorporeal circulating circuit includes a liquid chamber, a pressure measuring means, and a liquid flow path. The liquid chamber includes a reference surface not deformed by a pressure in the extracorporeal circulating circuit, a deforming surface disposed separated from the reference surface and deformed at least partially by a pressure in the extracorporeal circulating circuit, a first connection surface that joins the deforming surface with the reference surface to form a closed liquid-tight space inside them and is not deformed by a pressure in the extracorporeal circulating circuit, a liquid inflowing port provided in the side surface of the first connection surface, and a liquid outflowing port disposed away by ½ to less than one round from the inflowing port in the flowing direction of liquid introduced along the inner periphery of the side surface of the first connection surface.