Patent ID: 8644693

Claim:
An integrated micromachining proximity switch sensor in air/oil lubricators comprising: a micromachining silicon thermal sensor; an assembly package embedded with an flow channel; and an electronic, printed circuit board; wherein said micromachining silicon thermal sensor is further comprising one heater resistor and one ambient temperature resistor; said heater resistor is disposed on a thermally isolated suspending, silicon nitride membrane extending over a cavity which is formed by bulk etching from backside of said silicon substrate; wherein said ambient temperature resistor that is disposed on a non-membrane region of said silicon substrate, is functioned to measure ambient temperature and feedback to a heater resistor controlling circuit, wherein said MEMS silicon thermal sensor is packaged on sidewall of said flow channel and connected to said electronic printed circuit board for controlling heating voltage of said heater resistor to be constantly elevated above ambient temperature; and wherein said heating voltage of heater resistor is as an indication of heat dissipation rate of heater resistor corresponding to various media material; once measured said heat dissipation rate of heater resistor is abruptly lowered than a pre-set threshold value, then said electronic, printed circuit board will automatically send out an alarm signal to trigger and shut off the operation of mechanical system to avoid, oil/lubricants dry-out.