Patent ID: 7665365

Claim:
A pressure sensor comprising: a case; a detection unit attached to one end of the case; a housing member having a first surface, a first connection member, a second connection member, a passage, a pressure introduction hole and a second surface on which a first opening member is disposed, wherein the first surface of the housing member is coupled with the one end of the case; a diaphragm fixed to the housing member so as to cover the detection unit; and a sight glass for providing visible recognition of the cooling medium, the sight glass installed to the first opening member of the housing member, wherein the first and second connection members are connectable with a pipe in which a cooling medium flows, the passage connects the first connection member with the second connection member, the pressure introduction hole introduces a pressure of the cooling medium to the diaphragm from the passage, and the detection unit is capable of detecting the pressure of the cooling medium introduced from the first and second connection members through the passage and the pressure introduction hole, the pressure being applied to the diaphragm and transmitted to the detection unit.