1. Field of the Invention
The present invention relates to a pressure sensor apparatus for detecting or measuring a pressure of an object or fluid whose pressure is to be detected or measured such as, for example, a pressure sensor apparatus mounted on an intake manifold of an intake system of an internal combustion engine for detecting the intake air pressure. Hereinafter, the object or fluid whose pressure is to be detected or measured will be referred to as the fluid for measurement only for the convenience of description.
2. Description of Related Art
Heretofore, such pressure sensor apparatus is known in which invasion of foreign materials into a pressure sensor constituting a major part of the pressure sensor apparatus is prevented by providing a barrier plate for causing the foreign materials to flow around the pressure sensor. In this connection, reference may have to be made to, for example, Japanese Patent Application Laid-Open Publication No. 30535/1999 (JP-A-1999-30535) (FIG. 1).
In the pressure sensor apparatus mentioned above, invasion of the foreign materials into the pressure sensor can certainly be prevented by providing the barrier plate. However, to this end, it is required to prepare a dedicated barrier plate, which gives rise to a problem that the manufacturing cost of the pressure sensor apparatus is correspondingly increased, to a disadvantage.