Abstract: A dewatering system includes a selective calibrating sensor circuit configured to receive sensor readings from an electronic sensor, to determine if the electronic sensor is immersed in water, and to generate a control output signal accordingly. The selective calibrating sensor circuit periodically performs a self-calibration when the electronic sensor is not immersed in water to cancel the effect of potential contaminants deposited on the electronic sensor over its operating life. The selective calibrating sensor circuit inhibits calibration when the electronic sensor is immersed in water.

Abstract: A dewatering system includes a selective calibrating sensor circuit configured to receive sensor readings from an electronic sensor, to determine if the electronic sensor is immersed in water, to allow a user to adjust a pump down time in the field, and to generate a control output signal accordingly. The selective calibrating sensor circuit periodically performs a self-calibration when the electronic sensor is not immersed in water to cancel the effect of potential contaminants deposited on the electronic sensor over its operating life. The selective calibrating sensor circuit inhibits calibration when the electronic sensor is immersed in water. In some applications with multiple electronic sensors, the selective calibrating sensor circuit disconnects from one of the electronic sensors before performing the self-calibration.

Abstract: A dewatering system includes a selective calibrating sensor circuit configured to receive sensor readings from an electronic sensor, to determine if the electronic sensor is immersed in water, and to generate a control output signal accordingly. The selective calibrating sensor circuit periodically performs a self-calibration when the electronic sensor is not immersed in water to cancel the effect of potential contaminants deposited on the electronic sensor over its operating life. The selective calibrating sensor circuit inhibits calibration when the electronic sensor is immersed in water.

Abstract: A pump control system which can distinguish between water and oil so that a pump can be controlled to pump water and deactivated before oil is pumped. Sensing is accomplished by a pair of capacitive sensors, one located above the other in a vessel in which water accumulates. A dual mode frequency oscillator is associated with each sensor. Each sensor reacts to the dielectric constant of the liquid at the sensor by changing its capacitance, to thus detect the presence of a conductive substance, such as a liquid, to cause the sensor's oscillator to switch its mode of oscillation. The dual mode oscillator of each sensor selectively generates a control signal having two different duty cycles. As the dielectric constant of the liquid medium is sensed, a logic circuit interposed between the sensors allows the output of each sensor to be turned off when only the lower sensor is in water. The circuit turns on the pump only when both sensors are in water and the pump remains on until both sensors are out of water.

Abstract: A tire inflation device for delivering a fluid, such as carbon dioxide, from a liquid gas cartridge to a pneumatic tire wherein the device has a capability of controlling inflation to enable the user to achieve a preset desired tire pressure. A cartridge activating mechanism is provided. A cartridge securing mechanism is provided which prevents removal of an activated, unspent cartridge from the inflating device.

Abstract: A proximity detection system includes a dual mode oscillator for generating a pair of ON and OFF control signals. A sensing circuit including a capacitance device detects the presence of a conductive object, such as a liquid, to cause the oscillator to switch its modes of oscillation.

Abstract: A proximity detection system includes a dual mode oscillator for generating a pair of ON and OFF control signals. A sensing circuit including a capacitance device detects the presence of a conductive object, such as a liquid, to cause the oscillator to switch its modes of oscillation.

Abstract: A pliable hinged nonbuoyant flapper valve having a frusto conical projection for centering the valve in relation to a toilet drain, and for permitting the flapper valve to contact a toilet drain valve along a continuous line of engagement of seal the toilet valve. A chain connects the flapper valve to a toilet control lever. A ball float having a positive buoyancy slightly greater than the mass of the flapper valve is interposed an an adjusted location between the lever and the flapper valve for holding the flapper valve in an opened position to allow a predetermined volume of water to flow through the toilet drain.