Patent ID: 8558127

Claim:
A pressure switch comprising: a substrate; a contact pad disposed on a first side of said substrate; an electrical connector that is electrically connected to said contact pad that passes through said substrate to a second side of said substrate; a dome switch comprising a dome having a predetermined diameter and thickness that causes said dome to depress when subjected to a predetermined pressure of a pressurized medium, and a flange that forms a unitary structure with said dome, said flange surrounding a perimeter portion of said dome, said flange anchored to said first side of said substrate with said dome pressed against said contact pad with a predetermined preload force that is sufficient to establish an electrical connection between said contact pad and said dome, said flange being anchored to said substrate so that an airtight seal is formed between said flange and said substrate and so that said predetermined diameter of said dome is maintained at a substantially constant diameter during deflection of said dome, which substantially removes hysteresis resulting from depression and expansion of said dome so that said dome moves substantially elastically during said depression and expansion; at least one passageway formed in said substrate that allows said pressurized medium on said second side of said substrate to flow through said substrate to said first side of said substrate which causes said dome to depress and separate from said contact pad and electrically disconnect from said contact pad whenever said pressurized medium is greater than said predetermined pressure, and causes said dome to expand and electrically connect to said contact pad whenever said pressurized medium is less than said predetermined pressure.