Normally closed pressure-sensitive hydrophone switch

Abstract

A pressure-sensitive switch comprising an electrically-insulating base member having front and back surfaces with a through opening extending between the two at the center of the base member. Two electrodes are mounted on the base member's front surface and each have an electrically-conductive contact surface. A flexible diaphragm has its periphery secured in a fluid-tight manner to the back surface of the base member and is provided with a post connected to the central portion of the diaphragm. The post extends through the base member where an electrically-conductive washer is fixed to it where it extends beyond the front surface of the base member. A fluid-tight cap is secured to the front surface, covering an area above the washer and preventing fluid from entering the switch mechanism. The diaphragm, which is formed with plural corrugations, is exposed to the external pressure. When the switch is exposed to atmospheric pressure, the washer connects the electrodes, but when the switch is exposed to a super-atmospheric pressure, the central portion of the diaphragm pushes the washer out of contact with both electrodes, thus electrically disconnecting the two electrodes. The pressure-sensitive switch is especially useful with hydrophones, as in seismic streamer cables.