Some pressure sensors are configured to measure a pressure of a fluid to be measured flowing through an inside of a pipe. The pressure sensors include a pressure sensor including a joint connectable to a connected member of the pipe, the joint being provided with a pin for opening a valve of the connected member.
A typical example of this pressure sensor includes: a joint connectable to a connected member; a pressure sensor element welded to the joint; and an operation member provided to the joint, in which a valve provided in advance to the connected member is opened using the operation member in connecting the joint to the connected member (see, for instance, Patent Literature 1: Japanese Patent No. 4043874).
According to Patent Literature 1, the operation member is a pin, which includes a stepped cylindrical member and is welded to the joint. The joint and the pressure sensor element are welded to each other.
Another typical example of the pressure sensor includes: a printed circuit board (PCB) including a substrate; a carrier provided to a first surface of the substrate; a pressure converting member provided to a second surface of the substrate; and a fitting provided with the substrate (see, for instance, Patent Literature 2: U.S. Pat. No. 7,377,177).
According to Patent Literature 2, the carrier, which is fitted to a valve (e.g., a Schrader valve), functions as a pin of Patent Literature 1, and is made of metal. The fitting functions as the joint of Patent Literature 1.
However, the pin (i.e., the operation member) of Patent Literature 1, which is welded to the joint along the entire circumference thereof, should be made of metal, and sealability between the pin and the joint welded to each other is ensured. The metal pin includes, for instance, a stainless-steel cylindrical member that is to be subjected to a process such as grinding. Such a troublesome process limits the mass-production of the pin, which results in an increase in the production costs of the pin. Further, the joint, which is welded to the pressure sensor element, is also made of metal. Therefore, an increase in the weight of the sensor is inevitable due to an increase in the number of metal members.
Patent Literature 2 also entails the same problems as those of the typical device of Patent Literature 1 because the carrier, which corresponds to the pin of Patent Literature 1, is made of metal.