Abstract: An improved air-sampling pump of miniature size ideally suited for carrying on a person includes monitoring circuitry which controls motive pump-energizing signal applied to an air pump to ensure that sampled air is pumped through a test chamber at a substantially constant rate over an extended period of time and also includes alarm circuitry which provides comtemporary and residual indications of interrupted flow rate during the sampling period.

Abstract: A method and apparatus for regulating electrolyte solution level in a liquid rheostat. The liquid rheostat is used to control the motor speed of a primary pump which is operable for pumping liquid from a well. The liquid rheostat includes an electrode compartment mounted above an electrolyte solution reservoir and solution from the compartment may drain into the reservoir. A conduit interconnects the reservoir with the compartment and a circulating pump, driven by a variable speed electric motor, is operable for delivering solution from the reservoir to the compartment. A sensor is immersed in the well and develops a signal proportional to the amount of liquid in the well. The signal is received by a motor control which operates to vary the speed of the circulating pump motor, and thus the solution level in the compartment, reflective of liquid level in the well.

Abstract: A blood pump system in which a roller pump is provided for pumping blood through a flexible tube. A low voltage D.C. motor is provided having an output shaft. An electrical control circuit is connected to the motor for applying the necessary voltage to drive the motor at a predetermined speed. Gearing means are provided connecting the motor's output shaft to drive the roller pump. Means are optically coupled to the motor for controlling the speed of the motor. Means are connected to the optically coupled means to determine the blood flow rate being pumped through the tube by the pump. Means are provided which display a digital readout of the flow rate. The roller pump is provided with an arcuate bearing surface, which carries the flexible tube, the bearing surface defining an arc of approximately 168.degree.. Lead ramps extend from each end of the bearing surface and are substantially tangent to the end of the surface from which the respective ramp extends.

Abstract: Method and apparatus for matching the power output of a high slip motor to the demand requirement of a pumpjack unit. The stators of the high slip motor are automatically connected in various different configurations to provide the optimum torque as required by the pumpjack unit due to the downhole pumping conditions. A novel control circuitry is connected between the motor starter and the motor stators. The control measures the power drawn by the stators and selects the most optimum configuration thereof for the load required by the pumpjack. This selection operates the motor in the lowest possible torque mode, which is considered the best electrical and mechanical operation of the pumpjack apparatus.

Abstract: Control of a pumping station is accomplished in such a manner so as to maximize the energy efficiency of the pumping station by utilizing a variable drive pump to maintain the pipeline suction pressure seen at the input to the pumping station at an acceptable level. If the pipeline suction pressure decreases below a level which can be controlled by the variable drive pump, then a control valve located at the output of the pumping station is closed to the extent necessary to maintain the pipeline suction pressure at an acceptable level. If the pipeline suction pressure is greater than can be controlled by the variable drive pump then additional pumps are brought online to prevent overloading of the variable drive pump.

Abstract: A liquid level control for the operation of a sump pump or the like intermittently removing liquid from a sump or pit. The control starts the pump when the liquid level reaches a preset high level and maintains the pumping until the liquid reaches a preset low level. The control comprises a first switch which closes in response to the liquid crossing the preset upper level and a second switch preferably in parallel therewith which closes in response to pump motor current such that when the first switch starts the pump, the second switch maintains the pump in the on position.

Abstract: A fluid pump mechanism for delivering a smooth output of fluids to a system utilizing at least one piston in a chamber reciprocative therewithin. The piston has strokes that fill and empty the chamber in conjunction with the action of valve means located at the inlet and outlet of the chamber. Motive means causes reciprocation of the piston within the chamber. Control means is also included for minimizing the time during the piston cycle in which the piston is not emptying the chamber. The invention's scope also encompasses a pressure metering device for a fluid forcing means motivated by an electrical motor.

Abstract: Hydraulic surge protection is provided in a pumping plant by providing a synchronous motor/generator connected across the electrical power bus lines used to energize the motor operated pumps for pumping liquid through a pipeline. A fly wheel is provided on the synchronous motor/generator having an inertia to maintain the motor/generator operating in the event of an electrical power failure between the bus lines and source of electrical energy to generate and feed current to the pump drive motors through the bus lines to maintain pumping operation thereof. This pumping operation is maintained a sufficient length of time to minimize separation of the liquid column being pumped in the pipeline to an extent that damaging water hammer is prevented.

Abstract: A constant-volume increment pipetting arrangement for use particularly in connection with analysis of minute specimen volumes of biological fluids. The arrangement, which is designed to have a very low inertia factor, comprises a pumping unit having a pair of two-port valves with a duct running between a port from each valve, wherein at least a portion of the duct wall is movable to provide a variable volume pipetting chamber. The second port of one valve serves as the intake port for the fluid to be pipetted and the remaining port of the other valve serves as the delivery port. Three reciprocating drive elements are provided, connected one each to the valves and to the movable portion of the duct wall. Associated with the drive elements is a sequential control means, wherein the control means portion for the drive element connected to the moving portion of the duct wall constitutes an electromagnet arrangement energizable by a periodic supply.

Abstract: This is a method and apparatus for controlling an oil-well beam pumping unit in a manner which allows increased oil production. The AC electric motor of the beam pumping unit is supplied power through a variable frequency power supply, whose frequency (and voltage) is controlled by circuitry to automatically adjust to whatever flow enters the wellbore by varying the speed of the pumping unit to maintain the speed generally proportional to the real power consumed by the pump. As the level in the wellbore can be maintained at an essentially constant minimum level, despite the relatively large hour-to-hour variations in in-flow which normally occur, the total flow from the formation into the wellbore in a given period of time is increased.

Abstract: A drive system for a utility vehicle, such as a fork-lift truck, comprises a hydrostatic transmission whose pump is driven by an electric shunt-wound motor having a field winding so energized, under the control of a potentiometer responsive to the fluid pressure in the transmission, that the field current varies inversely with transmitted torque over at least a portion of the speed range of the vehicle. The automatic potentiometer control exerted by the fluid pressure may be overridden by a manually operable lever. The same potentiometer can be used to vary the motor speed in response to the output pressure of another pump which is driven by the electric motor and coupled with the fork-lifting mechanism of the vehicle.

Abstract: A fluid pump mechanism for delivering a smooth output of fluids to a system utilizing at least one piston in a chamber reciprocative therewithin. The piston has strokes that fill and empty the chamber in conjunction with the action of valve means located at the inlet and outlet of the chamber. Motive means causes reciprocation of the piston within the chamber. Control means is also included for minimizing the time during the piston cycle in which the piston is not emptying the chamber. The invention's scope also encompasses a pressure metering device for a fluid forcing means motivated by an electrical motor.

Abstract: This is a method and apparatus for controlling a downhole, hydraulically actuated pump. Two fluid flow monitoring means generate signals which are a function of the power fluid flow rate to the downhole pump and the return fluid flow rate from the well. An automatic controller causes the power fluid flow rate to be maintained essentially directly proportional to the return flow. Thus, the power fluid flow is not varied in the opposite direction of any change in return flow to maintain the return fluid flow constant, but conversely, is changed in a manner which will tend to accentuate any changes in the return fluid flow.

Abstract: A circuit to maintain the water level between low and high predetermined limits in a sump in which the signal from an upper limit probe operates a first lamp which illuminates a photo resistor controlling the gate of a triac. The triac turns on and enables a second lamp connected to a lower limit probe which illuminates the photo resistor and holds the triac on until the fluid level drops below the lower limit probe.

Abstract: A flow rate controlled angiographic injection system is provided with an overspeed injection protection means. The injection system includes a motor driven syringe injector and a flow rate controller responsive to the overspeed protection means to drive the motor to inject a contrast medium from the syringe into a blood vessel at a desired flow rate when the actual flow rate from the syringe is less than or equal to the predetermined flow rate, and to disable the motor otherwise. The overspeed injection protection means includes a means for generating a signal representative of the actual flow rate of a contrast medium from the syringe by detecting the back emf induced in the motor armature, compensation being made for the resistive voltage drop in the armature windings and brushes.

Abstract: A pump-off control unit for use in conjunction with a motor driven pumpjack assembly which is connected to reciprocate a downhole production pump. A current transformer connected to the pumpjack motor compares the time interval of a no-load portion of the pumping cycle to a second time interval, and shuts in the well when the ratio between the two intervals changes an amount which indicates a pump-off condition of the downhole pump assembly.

Abstract: A controller maintains a constant desired fluid pressure in a fluid load driven by a variable flow fluid pump with a variable speed motor. A set point signal representing desired pressure and a signal from a pressure transducer representing actual pressure are applied to an error amplifier. The resulting error signal is applied through a variable gain stage to the motor control. The variable gain stage includes first and second variable gain amplifiers the first of which has a gain which is controlled inversely to pressure. The second variable gain amplifier has a gain which is controlled in proportion to flow. In this manner, the gain of the controller changes in inverse proportion to the restriction of the fluid load. This makes the performance of the controller independent of changes in the fluid load by keeping the total loop gain constant.

Abstract: A pump assembly is disclosed which includes a pump which is externally controlled to vary with time the volume and/or the pressure of fluid pumped therethrough. A memory unit is programmed to provide a desired volume-time and/or pressure-time characteristic. The output of the memory is utilized to drive the pump to provide the aforementioned pump characteristics. Provision is made for appropriately modifying the stored program in accordance with preselected parameters so that the pump can, for example, operate in conjunction with an artificial heart.

Abstract: A control circuit for turning off the power to the pump drive motor when the pump has exhausted the supply of liquid in the well. Means for sensing the instantaneous current to the pump motor and a circuit measuring the average current drawn by the pump drive motor, and turning off the power when the average current decreases below a preset level. An RC circuit having a time constant greater than the time required for the pump to complete one full pumping cycle for measuring the average current to the motor, and a comparator controlling switching means to shut off the power when the average current to the motor decreases to a predetermined amount. A reference voltage supplied to the comparator from an amplifier connected to the electrical power in which the output of the amplifier varies inversely to variations of the voltage of the electrical power thereby preventing fluctuations in the supply voltage from adversely affecting the control circuit.

Abstract: A system for the linear control and calibration of the flow of fluid through a pump in which the pump has a linear flow rate-to-fluid propeller speed relationship over a range of flow rates. A DC motor driving the fluid propeller has a linear drive speed-to-armature voltage relationship over a corresponding range of drive speeds. The voltage applied to the armature is regulated DC, the value of which provides an indication of the fluid flow rate. The system has particular utility in portable air pollutant measuring applications where a measured volume of air is pumped through a filter tube filled with a porous solid sorbent which is later subjected to chemical analysis.