US Patent 7216545 Acid-resistant pressure sensor

A pressure sensor includes a housing with which terminals are insert-molded, a sensing element mounted on the housing and electrically connected to the terminals, an electrically insulating protective member for covering the terminals and the sensing element. The protective member has a triple-layer structure. The first protective member for covering the terminals has high elasticity to prevent bubbles from being produced in the protective member. The second protective member for covering the sensing element has low elasticity to reduce stress applied to the sensing element. The third protective member having higher acid resistance covers the second protective member so that the sensor has high acid resistance without sacrificing the sensor characteristics.