Abstract: A method of operating a submersible pumping system includes the steps of placing the pumping system in a normal mode of operation and then detecting the possible presence of a gas slug in proximity to the pumping system by measuring a decrease in the load on the motor. Once the possibility of a gas slug has been detected, the method continues by placing the pumping system in a reduced speed cycle. The pumping system is kept in the reduced speed cycle until the absence of a gas slug in proximity to the pumping system is detected by evaluating two independent conditions within the pumping system.

Abstract: A method of operating a submersible pumping system includes the steps of placing the pumping system in a normal mode of operation and then detecting the possible presence of a gas slug in proximity to the pumping system by measuring a decrease in the load on the motor. Once the possibility of a gas slug has been detected, the method continues by placing the pumping system in a reduced speed cycle. The pumping system is kept in the reduced speed cycle until the absence of a gas slug in proximity to the pumping system is detected by evaluating two independent conditions within the pumping system.

Abstract: A pirani absolute pressure sensor for sensing absolute pressure in a load lock in a range from 100 to 10?4 torr and a differential pressure sensor for sensing a pressure difference between ambient atmospheric pressure and pressure in the load lock chamber are combined together in a module with a manifold and common circuit components to provide a pressure transducer that is capable of producing not only analog output for absolute pressure measurements, but also control signals at settable absolute and differential pressure values for opening interior and exterior doors of a load lock used to shuttle wafers and other devices into and out of a vacuum processing chamber. The transducer can also produce signals to control transition from slow to fast vacuum pumping of the load lock chamber at a settable threshold pressure.

Abstract: Transducer apparatus and method combining both an absolute pressure sensor for sensing absolute pressure in the load lock chamber and a differential pressure sensor for sensing a pressure difference between ambient atmospheric pressure and pressure in a load lock chamber and provides control signals for opening an interior door from the load lock chamber into a vacuum processing chamber and for opening an exterior door between ambient atmosphere and the load lock chamber. The transducer can also produce signals to control transition from slow to fast vacuum pump-down of load lock chamber pressure at a predetermined pressure set point.