| 摘要 |
PURPOSE:To prevent the clogging of a through hole on a pedestal due to sticking of a foreign matter, chewing gum or the like by providing an orifice with the opening sectional area of more than about 3mm.<2> in a pressure introduction port. CONSTITUTION:A piezo-resistance type strain gauge chip 8 has a dent formed on the back thereof and is junctioned to a Pyrex glass 10 having a through hole 9 of about phi0.8mm.. Chip 8 is connected to a thick film circuit board 12 comprising an amplification circuit or the like having an electronic component 11 with a gold fine wire 13 from an input/output terminal and an input/output terminal of the board 12 is connected to a lead terminal 15 with a lead frame 14. The glass 10 junctioned to the chip 8 is bonded 19 to a housing 18 having a pressure introduction port 17 with a connector 16 molded. A port 17 having an orifice 20 about 2.3mm. in the diameter has the opening area ratio of about 1/2 with respect to about 3.3mm. in the inner diameter 21 of the port 17 so as to reduce the speed of a gas in the port 17 sharply while generating a turbulence. Thus, pollutant contained in the gas prevents a foreign matter from running into the through hole 9 of the glass 10 thereby preventing the clogging of the through hole 9 due to a chewing gum or the like. |
