Disposable pressure transducer and disposable pressure transducer apparatus

A disposable pressure transducer for measuring fluid pressure, connectable to external display means for displaying said measured fluid pressure, comprising:

• a housing including a fluid chamber having:
• at least one inner wall surface;
• an inlet having a given cross-sectional area;
• an outlet having a cross-sectional area smaller than said cross-sectional area of said inlet;
• a sensor accommodating chamber;
• an aperture between said fluid chamber and said sensor accommodating chamber;
• and
• said at least one inner wall surface of said fluid chamber being hydrophilic;
• said fluid chamber and said sensor accommodating chamber being formed integrally with each other;
• a sensor assembly mounted in said sensor accommodating chamber having:
• an insulating board;
• a semiconductor sensor chip mounted on said insulating board for converting pressure into a sensor output signal;
• integrated circuit means mounted on said insulating board for processing said sensor output signal into a pressure signal;
• a cylindrical coupling lid having an interior and a mouth leading into said interior, said coupling lid being mounted in said aperture and on said insulating board to surround said semiconductor sensor chip;
• said mouth of said coupling lid having a selected cross-sectional area;
• a pressure transmitting medium in said interior of said coupling lid to provide electrical insulation between said fluid chamber and said semiconductor sensor chip;
• electrical connector means for electrically connecting said insulating board to said external display means;
• said semiconductor sensor chip including a diaphragm portion having a preselected cross-sectional area;
• and
• the ratio of said selected cross-sectional area of said mouth of said lid to said predetermined cross-sectional area of said diaphragm being at least 5:1.