Abstract: A drive unit for driving a fuel pump for a small-sized vehicle, which is capable of reducing the current consumption of the fuel pump. A drive unit includes an ECU for controlling the fuel injection amount of a fuel injector. The ECU drives the fuel pump on the basis of control data for controlling the fuel injection amount of the fuel injector and of a power supply voltage of the fuel pump. For example, the fuel pump is driven under pulse-width modulation (PWM) in such manner that a pulse-width of a PWM signal is made larger with an increase in the injection amount of the fuel injector and is made smaller with a decrease in the fuel injection amount of the fuel injector.

Abstract: A system for increasing the volumetric flow uniformity of fluid pumped through a conduit by an infusion pump. A pumping mechanism operates in identifiable step movements that are broken down into microstep movements that are then grouped into packets. The pumping mechanism controls the period of each microstep, so that the sum of the microstep periods in a packet is essentially equal to the packet period, with little or no waiting time on the motor. The motor preferably begins moving the assigned microsteps in each packet immediately upon the beginning of the time period, but controls the period of the microsteps for that packet.

Abstract: A secondary air fan for an internal combustion engine includes a housing in which a motor unit drives a pump unit, the housing having an air inlet channel and an air outlet channel, an air mass sensor, being arranged in one of the channels to control the motor unit by an electronic unit. The air mass sensor is connected to the electronic unit which is attached to the housing and/or to the air inlet channel or to the air outlet channel.

Abstract: A fuel dispensing system compensates for varying fuel source flow rate requirements based on fuel dispenser feedback signals. A pumping system pumps fuel from one or more fuel sources to one or more fuel dispensers through associated conduits. When actively dispensing fuel, each fuel dispenser monitors its actual fuel discharge rate and adjusts an integral flow control device to maintain a nominal fuel discharge rate. When an active fuel dispenser fails to achieve its nominal fuel discharge rate, it indicates this condition to the pumping system via its dispenser feedback signal. In response, the pumping system increases its pumping rate until the fuel dispenser achieves its nominal fuel discharge rate. Other active fuel dispensers adjust their flow control devices as needed to maintain their nominal fuel discharge rate in response to the adjusted pumping rate.

Abstract: An electrohydraulic pressure supply unit involving the joint operation of two energy converters, which can be adjusted independent of each other, including an electric motor with speed control that drives a variable displacement pump with a variable displacement volume. The electric motor converts electrical output (loss-encumbered), into mechanical output, meaning into speed n and torque T. The pump then converts this mechanical output (also loss-encumbered) into hydraulic output. The hydraulic output is determined by the pressure difference &Dgr;p across the pump and the volume flow Q. The pressure difference &Dgr;p generally is impressed by the consumer or load on the system. The volume flow Q is the result of the displacement volume V and the motor speed n. The torque T, which must be generated by the motor, is derived from the displacement volume V and the pressure differential &Dgr;p.

Abstract: An engine idle controller for an engine driven pressure washer. The pressure washer delivers high pressure water from a pump through the idle controller to a conventional wand which includes a manually operated, normally closed flow control valve and a spray nozzle. When the wand valve is opened, a resulting pressure drop between two chambers in the flow controller acts on a piston to move the engine throttle to a full throttle position. When the wand valve is closed, the pressures in the chambers equalize and the piston is moved to a position to set the engine throttle to an idle position.

Abstract: The centrifugal pump unit includes a flow switch arranged within the pump housing in the flow path of a delivery fluid, which essentially consists of an electromagnetic switch device and a two-armed, pivotably mounted lever whose one arm projects into the flow path and whose other arm carries a magnet which is in contact-free active connection with the switch device. The switch device is arranged within a terminal box mounted on the unit housing. The lever is seated within a switch housing which is incorporated in a cartridge-like manner into the pump housing and which is hermetically sealed to the outside and which is arranged neighbouring the terminal box that such it is only in magnetic active connection so that the reed contact located in the terminal box is controlled by the magnet located in the switch housing. In this manner a usual terminal box may be used which does not need to be sealed with respect to the delivery flow.

Abstract: A method for regulating coolant flow rate to a heat exchanger in an automotive vehicle is described. The method includes the steps of providing a main fluid pump for providing a source of fluid under pressure to the vehicle engine and the heat exchanger and providing a reversible flow auxiliary pump between the main fluid pump and the heat exchanger. The method further includes the steps of generating an engine speed signal and an ambient temperature signal. The auxiliary pump forces fluid against the flow from the main fluid pump when the engine speed signal is greater than a threshold value and forces fluid to the heat exchanger when the ambient temperature signal is below a predetermined value and the engine speed signal is less than the threshold value and within predetermined values. A system is also disclosed for accomplishing the method.

Abstract: A system for increasing the volumetric flow uniformity of fluid pumped through a conduit by an infusion pump. A pumping mechanism operates in identifiable step movements that are broken down into microstep movements that are then grouped into packets. The pumping mechanism controls the period of each microstep, so that the sum of the microstep periods in a packet is essentially equal to the packet period, with little or no waiting time on the motor. The motor preferably begins moving the assigned microsteps in each packet immediately upon the beginning of the time period, but controls the period of the microsteps for that packet.

Abstract: A method for controlling working fluid surge in a centrifugal compressor. According to the method, surge detection is accomplished by calculating the change in the compressible fluid mass flow rate that accompanies surge in a compressor, the compressor having means for sensing a first fluid temperature, means for sensing a first pressure, means for sensing a second pressure, and means for measuring current drawn by a compressor prime mover, the method comprising the steps of: calculating the time rate of change of the first fluid temperature; calculating the time rate of change of the first fluid pressure; calculating the time rate of change of the second fluid pressure; calculating the time rate of change of current drawn by the compressor prime mover; calculating the mass flow rate by combining the calculated rates of change; and comparing the calculated mass flow rate to a predetermined acceptable mass flow rate to determine if surge is present.

Abstract: A system for increasing the volumetric flow uniformity of fluid pumped through a conduit by an infusion pump. A pumping mechanism operates in identifiable step movements that are broken down into microstep movements that are then grouped into packets. The pumping mechanism controls the period of each microstep, so that the sum of the microstep periods in a packet is essentially equal to the packet period, with little or no waiting time on the motor. The motor preferably begins moving the assigned microsteps in each packet immediately upon the beginning of the time period, but controls the period of the microsteps for that packet.

Abstract: Flow parameters in a fluid delivery assembly are determined by monitoring pressure responses and processing those responses along with information regarding the fluid flow. In one aspect, a processor controls the pump to pump flow quantities in accordance with a pseudorandom code. Portions of the resulting pressure signal sensed at the conduit is averaged, and the averaged values are then decoded in accordance with the pseudorandom code. An estimate of the equilibrium pressure is generated from the decoded average pressure values, while a summation of the pressure samples is generated from the undecoded pressure signals. The resistance to fluid flow of the system is determined from the estimated equilibrium pressure and pressure summation. For low flow rates, a processor controls the pump to pump fluid in a series of fluid boluses, with each fluid bolus delivered in the beginning of a separate timeslot.

Abstract: The present invention provides a method and apparatus for controlling the production rate of a rotary downhole pump to prevent well pump-off. The method includes the steps of operating the pump at a first speed less than a maximum rate of the pump until well fluid is produced at the wellhead. The operation is continued at the first speed until a first dynamic fluid level in the annulus between the production tubing and the wellbore or the well casing is stabilized. A first static load on the drivehead at the first dynamic fluid level is determined. The pump is then operated at a second speed higher than the first speed until the fluid level in the annulus is stabilized at a second dynamic fluid level. A second static load on the drivehead at the second dynamic fluid level is determined. A linear function of the load on the drivehead is determined as a function of the fluid level in the annulus.

Abstract: A system for metering a fluid, such as a catalyst in an industrial chemical process plant, includes a controller, a drive pump assembly and an injection pump assembly. The drive pump assembly forces reciprocation of the injection pump assembly via a controlled flow of hydraulic fluid. The injection pump assembly includes a drive cylinder and at least one injection section. The drive cylinder receives pressurized fluid from the drive pump assembly and causes metered fluid to be drawn into and expelled by the injection section. The position of reciprocating components of the injection pump assembly is detected between stroke limits and converted to a velocity signal. Closed-loop control of the flow from the injection pump assembly is implemented by the controller via the drive pump assembly based upon the actual velocity of the reciprocating components of the injection pump assembly and a commanded velocity.

Abstract: In accordance with the present invention, there is provided an in-line fluid pump controller for activating and de-activating a fluid pump which is configured to pump fluid through a fluid line. The fluid in the fluid line is characterized by a flow rate and a pressure. The pump controller is provided with a housing which is connectable in fluid communication with the fluid line. The pump controller is further provided with a valve body which is disposed within the housing. The valve body is in fluid flow communication with the fluid of the fluid line and is sized and configured to move in response to the flow rate of the fluid. The valve body has a first position when the flow rate of the fluid is below a threshold flow rate and a second position when the flow rate of the fluid is above the threshold flow rate. The pump controller is further provided with a pivoting lever arm which is rotably connected to the housing. The lever arm is sized and configured to move in response to the pressure of the fluid.

Abstract: In a high-pressure cleaning apparatus comprising an electric motor, a high-pressure pump driven by the electric motor, and an automatic switching-off means for the electric motor including a switch actuatable by an actuating element moveable in dependence upon the pressure or the flow of the liquid being conveyed by the high-pressure pump, in order to reduce the switching expenditure it is proposed that a switching-off element which is manually actuatable on the high-pressure cleaning apparatus be associated with the same switch so that in one position of the switching-off element, the switch cuts off the power supply to the electric motor independently of the pressure or the flow of the liquid being conveyed, whereas in the other position the switch is actuatable by the actuating element.

Abstract: A booster water pump for increasing source water pressure to a high water pressure for industrial use, has an elongated tubular hollow cylinder having both ends closed with a cylinder inlet port in one end, and a cylinder outlet port to permit the cylinder to be filled with source water. The pump has a submersible motor and hydroturbine pumping unit so articulated that turbine impellers are adjacent the motor and a turbine outlet is away from the motor, the motor-pump unit fitting in the tubular cylinder. The water passageway is annular and the turbine outlet is attached inside the cylinder to the cylinder outlet port. The pump is highly portable and effective to provide high pressure water to remote locations from low pressure sources.

Abstract: A submergible pumping unit for raising viscous fluids from a well is driven by an electronic drive and control system, a first portion of which is located above the well, and a second portion of which is coupled to the submergible pumping unit. The drive and control system includes a power supply circuit located above the well for converting AC power from a source to DC power having current and voltage levels. The DC power is transmitted to the pumping unit via a two-conductor DC bus cable. The pumping unit includes a switching circuit which receives the DC power for driving a submergible motor, such as a permanent magnet brushless motor. The speed of the motor, and of a pump coupled thereto, is proportional to the voltage of the DC power applied to the pumping unit. The pump is preferably a progressive cavity pump, and the drive and control circuitry provides sufficient torque to start the pump from a static condition.

Abstract: A new pump shut off system for shutting off a pump when there is insufficient fluid to pump through the pump. The inventive device includes a pump with a primary switch for selectively activating and deactivating the pump. A processor is electrically connected to the primary switch. The processor has a timer for measuring a predetermined amount of time. The processor deactivates the pump after the timer measures the predetermined amount of time. The processor also has a flow switch with a flow sensor in an outlet conduit of the pump. The flow switch deactivates the timer to prevent the timer from measuring the predetermined amount of time when the flow switch is activated by the flow sensor when the flow sensor detects fluid flow through the outlet conduit above the predetermined amount during the predetermined amount of time.

Abstract: A demand system is disclosed for controlling the output airflow from a pneumatic source in response to changes in airflow demand. The source includes a pressure sensitive bypass mechanism in fluid communication with a discharge manifold to divert unwanted airflow and a linear electronic limiter with a limiter signal input to control the pneumatic source and proportionally adjust output airflow into the discharge manifold. The demand system includes an airflow detector operative to produce a linear output signal proportional to the airflow through the bypass mechanism and a controller. The controller includes an input connected to the airflow detector and an output connected to the electronic limiter input and operative, as the airflow detector senses airflow through the bypass mechanism, to produce a linear output signal representative of the airflow to the limiter for altering the pneumatic source output.

Abstract: According to an infusion method and pump, in order to perform infusion at a flow rate with high accuracy by allowing finger members to appropriately press a predetermined portion of an outer diameter (outer surface) of an infusion tube whose outer diameter accuracy is assured, thereby causing the infusion tube to perform a peristaltic motion, the infusion tube is stationarily held between a plurality of fingers which are arranged along the longitudinal direction of the infusion tube having a predetermined outer diameter and independently driven, and a holding means. The infusion tube is pressed from the outer surface to supply a liquid by setting a small moving amount of each finger to a degree enough to eliminate the influence of the wall thickness of the infusion tube and individually driving the fingers.

Abstract: A method for detecting the occurrence of surge in a centrifugal compressor includes the step of calculating a time rate of change of a discharge pressure of the fluid discharged from the compressor. In one preferred embodiment, the time rate of change of the discharge pressure is calculated by initially setting PREV PRESS and RATE PRESS variables equal to zero (0), and commencing a RATE PRESS subroutine having a time limit for cycling therethrough. The RATE PRESS subroutine includes the steps of obtaining a discharge pressure reading for the fluid discharged from the compressor, subtracting the discharge pressure reading from the PREV PRESS variable to establish the RATE PRESS variable, and resetting the PREV PRESS variable equal to the value of the discharge pressure reading. After the RATE PRESS variable has been determined, the RATE PRESS is compared with an acceptable set time point rate of change for the discharge pressure.

Abstract: The device comprises: a flowstat 16 with a slider 16B with a built-in magnet 22 designed to interfere with a proximity-operated electric switch 20A; a variable-volume chamber 1 with a flexible wall 9 and spring means 28 that tend to reduce its volume; and a slider 26 combined with said flexible wall 9 and comprising a cam profile 30 acting on the movable slider 16B of the flowstat in the event of a drop in pressure in said chamber 1, in order to displace said slider 16B in the same direction in which the slider is displaced by the flow that passes through the flowstat; by this means the pump is actuated to restore the pressure in said chamber 1; whereas when the pressure in said chamber 1 drops further, owing to a lack of supply of liquid to the pump, the cam profile 30 ceases to act on the movable slider 16B and the pump stops.

Abstract: The invention relates to equipment for cleaning objects such as tanks, pipeline systems etc. in a food treatment plant. The equipment includes a liquid conveying system which is arranged to convey a variable controlled amount of liquid at a variable controlled flow rate. In series with this means system there is a volume and/or flow rate metering device and a control device connected to the volume and/or flow rate metering device and receiving a signal from the metering device. The control device is arranged to actuate the conveying system in response to this signal so that the desired amount of liquid is conveyed at a desired flow rate. The conveying system and the volume and/or flow rate metering device are arranged in a flow path supplying rinsing or cleaning liquid to one or several objects to be cleaned.

Abstract: A control system and method for controlling a pump having a fluid passage therein, including a sensing means for sensing fluid flow through the fluid passage wherein the control system controls the actuation period of the pump as a function of a characteristic of the fluid flow sensed by the sensing means. The sensed characteristic is the quantum rate of fluid flow through the fluid passage.

Abstract: A fluid delivery method and apparatus implementing active phasing to actively restore the substantially exact mechanical positions of driven components in a delivery system in order to precisely reproduce the mechanical signature and hydraulic characteristics of the system from run to run without perturbing output flow. The delivery system is configured to intelligently drive pump pistons to a known position and to deliver fluid(s) at a known pressure, and includes a plurality of pump modules each including motor driven syringes having respective pistons configured to reciprocate under control of a control mechanism. Pump phasing is accomplished through a mechanism of compensation delivery of the syringes. An independent, motor-driven syringe of any given pump in a plurality of pumps in a system has the ability to act as a delivering syringe to maintain a prescribed output flow while one other syringe of each of the plurality of pumps is repositioned under load.

Abstract: This disclosure relates to a vapor recovery unit of a fuel dispenser, and comprises a vapor pump, a variable speed electric motor coupled to drive the pump, and an electric control package connected to control the speed of the motor, the foregoing components being located in an integrated unit housing. The pump comprises a positive displacement vapor pump such as a vane pump; the motor comprises a variable speed induction motor; and the control package is operable to receive fuel-flow representative pulses from one or two flow meters, and to vary the pump-motor speed to recover substantially all of the displaced vapor during fueling. The unit housing is preferably installed in a dispenser cabinet and hydraulically coupled in a vapor flow pipe and electrically connected to receive the fuel flow pulses from one or two fuel flow meters. The vapor recovery unit is useful as original equipment (OEM) and/or as a retrofit component.

Abstract: A control system for an aircraft's electrically driven hydraulic pump. An electronic motor controller having closed loop feedback is utilized to directly control the prime mover speed in response to pump loading.

Abstract: Apparatus comprising a flow carrier connectable in a liquid flow system including an electric motor-pump unit and a conduit for conveying a pumped liquid to a liquid utilization apparatus. The flow carrier is connectable in the conduit and includes an opening which exposes the liquid flowing through the carrier. A heat sink or cold plate is located on the carrier over the opening, the heat sink covering the opening and having a wet side exposed to the liquid. The heat sink further includes a dry side, and heat generating electrical control components are secured to the dry side. A sensor is also mounted on the heat sink and responds to a characteristic, such as the pressure, of the liquid. A heat insulating layer extends around the control components and the sensor and covers the dry side of the heat sink, the layer preventing condensation. The sensor and the control components are operable to control the motor-pump unit.

Abstract: Systems and methods for pressure reduction, including a first conduit with a pressure sensor, a static restriction device, and second conduit connected therebetween. Fluid is introduced through the second conduit as a function of the pressure sensed by the pressure sensor, thereby compensating for fluctuations in sensed pressures due to restriction device degradation and other factors.

Abstract: An automatically controlled fluid flow responsive method for achieving de-energization of an electric motor operatively connected with a downhole pump being connected to a production tubing string of a well when flow from the downhole pump becomes abnormally low. A selective electronic cut-off signal is programmed, representing a selected minimum acceptable rate of discharge flow from the downhole pump. A flow transducer provides an electronic flow related signal to the control circuitry, representing actual pump discharge flow. The control circuitry is also programmed with a selected electronically controlled time delay period which is initiated when the flow related signal becomes less than the selective cut-off signal. When the flow related signal remains less than the cut-off signal for the duration of the time delay period the control circuitry interrupts the electrical power supply to the pump motor.

Abstract: An infusion device with a disposable administration set which is inexpensive to manufacture. In the preferred embodiment of the present invention the disposable administration set has a plurality of elongated cam followers connected to a plate assembly, wherein the cam followers are displaced in a predetermined sequence and forced against a delivery tube by cam means driven by rotary drive means. The disposable administration set is injection molded as a single integral piece. The disposable administration set includes adjustment spacers disposed between the plate assembly and the cam followers which adjust the distance between them to keep the device accurate. In the preferred embodiment of the present invention the cam means are configured to provide fluid delivery at a consistent and uniform rate. The device may also incude a pressure sensing pin positioned on the cam assembly which contacts the tubing during the pumping cycle.

Abstract: A procedure for adjusting a filling jet of flow-controlled automatic filler machines. The task is of providing an inventive solution, ensuring an even, clean supply of the medium volume flow via the filling pipe into the container. The task is solved by determining and storing the speed of a filling jet emerging from a filling pipe. The actual speed values of a volume flow emerging from a pump is measured with a speed sensor and the thus gained values are compared in order to adjust the speed of an emerging filler jet. At the same time the flow output of the pump is changed until the stored set value of the filler jet speed at the volume sensor corresponds to the speed of the medium volume flow measured at the speed sensor. Only then the filling process into the vessels is started.

Abstract: A method and apparatus for controlling the speed of a progressing cavity liquid well pump by driving the pump with a variable speed drive device while measuring the amount of liquid production from the pump. The speed of the pump is varied in speed steps, either upwardly or downwardly, by the variable speed drive device while measuring liquid production, to maintain a linear relationship between liquid production and pump speed.

Abstract: In a piston pump for pumping liquid carbon dioxide at a temperature below 30 degrees Fahrenheit and pressures at least as high as 7500 psi, the volume leaving the pump is determined by measuring only pressure or other parameter related to flow and movement of the plunger. The position of the piston is measured and the resulting displacement is integrated to determine volume of fluid pumped.

Abstract: A method and apparatus for evacuating a vacuum system which includes an evacuating portion comprising first and second vacuum pumps which are connected in series. The method and the apparatus are characterized in that the first vacuum pump is operated in a range from reverse rotation to forward rotation, and the second vacuum pump is rotated unidirectionally, thereby enabling pressure control of the vacuum system over a wide range.

Abstract: A device for constant, automatic regulation of water pressure and flow in a water supply plant, comprising an electric pump fitted in the main water pipe, an adjustable pressure switch connected to the main water pipe, and an electronic control unit, which switches the pump on if the pressure falls short of a predetermined level or switches it off if a predetermined pressure level is exceeded. The device is characterized in that a turbine, incorporated in the water pipe, acts as a sensor, cooperating with a rotation signal transmitter which is connected to the electronic control unit in order to keep the pump switched on as long as the sensor detects a flow of water.

Abstract: A pump for use in additive systems such as foam chemical additive systems for fire fighting water, the pump including impeller elements and flow meter elements in a common casing. The pump casing provides a gear pump arrangement using two enmeshed gears on an inlet side, and a closely adjacent gear flow meter arrangement downstream of the gear pump arrangement within the same pump casing. The gear flow meter elements are driven only by the force of liquid pumped by the enmeshed gears of the gear pump and cause very low pressure drop across the flow meter elements. Therefore, inaccurate measurements of flow rates due to slippage and viscosity variation are reduced compared to measuring the rotary speed of gear pump gears directly. The system is optimally used to meter and add foam chemical into a pressurized water line for fighting fires.

Abstract: In a magnetically suspended type pump, an operating state of the pump can be obtained without using a pressure gauge and a flowmeter. In addition, in the case where the magnetically suspended type pump is applied to a blood pump, in order to reduce the number of connections in a flow path and to avoid thrombus formation, a correlation between current flowing in a motor and flow or a correlation between current flowing in the motor and pressure is obtained in advance, and the speed of rotation of motor is varied by a speed of rotation control circuit in response to an instruction from a CPU circuit, based on the obtained correlation between current and flow or between current and pressure, whereby flow or pressure is controlled.

Abstract: A pumping mechanism moving in movement increments is controlled to space those movement increments in direct proportion to the volume resulting from each movement increment. In a further aspect, movement increments are grouped to result in approximately equal volumes per group. The mechanism moves continuously through the movement increments in each group. Groups are spaced to result in approximately equal flow volumes per group. The number of groups decreases as the flow rate increases. The number of movement increments in each group and the volume of each group increase as the flow rate increases.

Abstract: The invention is based on the premise that, for a given air blower, the current I consumed by the electric motor, the rotational speed N and the air flow rate Q are interconnected, regardless of the dynamic pressure, by a law Q=f(I, N) which can be experimentally determined on a ventilation bench. In order to perform any adjustment, I and N are measured, from which a calculator derives Q by means of the above-mentioned law. The comparison of the calculated value with the desired flow rate Qd provides an error signal which is applied to a control device which determines the supply voltage (U) of the motor of the blower. The invention is applicable to heating or air-conditioning installations for the passenger space of vehicles.

Abstract: A pump housing is provided with a conduit extending through the housing between a pump inlet and pump outlet. A pump device is disposed within the housing and in communication with the conduit to pump fluid therethrough. A fluid flow meter also is disposed within the housing and in communication with the conduit to monitor fluid flow rate through the conduit. The fluid flow meter generates signals related to the fluid flow rate which are fed back to a control device operable to control the flow rate through the pump device. The flow meter may include a pair of meshed modified elliptical gears. The modified elliptical gears are based on a true elliptical shape, with bulged portions added between the major and minor axes of the elliptical shape. The modified elliptical gears have involute teeth that are relatively thick adjacent the minor axis and relatively thin adjacent the major axis.

Abstract: The present invention relates to a downhole hydraulic pump monitoring system and more specifically relates to a system which detects and/or anticipates pump malfunctions by processing readings taken by a pressure transmitter on the operating pressure and the stroke rate of the downhole hydraulic pump where decisions are reached regarding positive pump operation or inefficient pump malfunction based upon comparisons between the instantaneous pressure readings of the pressure transmitter and a time-averaged operating pressure of the power fluid taken over a multitude of pump strokes.

Abstract: In order to create a safety device (1) by means of which reliable protection of the pump can be achieved as simply as possible, it is proposed that safety device (1) have a housing (4) provided with an inlet (5) and an outlet, inside which housing a first detection device with a transmitter element in the form of an impeller (7) provided with measuring blades (9) and a central part (10) are provided to determine the liquid throughput and a second detection device (24) in the form of a probe for detecting the liquid, both of which are connected with a control device for the pump.

Abstract: A method and apparatus for automatically shutting off a dispensing device when the fluid source tank is empty includes a programmed pump controller in communication with the dispensing device and a flowmeter having a pulse generator. Upon startup of the dispensing device, the controller waits for an initial time period, then periodically determines the pulse frequency which correlates to a rate of fluid flow. The pulse frequency is compared to a calculated average pulse frequency and, if the pulse frequency has changed a pre-selected, pre-determined amount or percentage when compared to the average pulse frequency the dispensing device is shut-off. The change in pulse frequency indicates ingestion of air into the pumping system meaning an empty source tank.

Abstract: Systems and methods for pressure reduction, including a first conduit with a pressure sensor, a static restriction device, and second conduit connected therebetween. Fluid is introduced through the second conduit as a function of the pressure sensed by the pressure sensor, thereby compensating for fluctuations in sensed pressures due to restriction device degradation and other factors.

Abstract: A controller for controlling the pumping unit for an oil well comprises a housing having a first and a second tip for placement in a flow of oil between the wellbore to holding tanks; means for generating a substantially constant power; a constant power heater in the first tip connected to the means for generating, for radiating a substantially constant heat; means for determining the temperature at each the first and second tips and for generating a digital signal indicative of the temperature of the first and second tips; supervising means for controlling the means for determining, processing the digital signal for determining a rolling average signal, and generating a control signal therefrom which is independent of ambient temperature of the oil flow; and means for switching the pumping unit on or off, according to the control signal. The controller further comprises means for calibrating the means for determining. The constant power heater is preferably a FET connected in series with a resistor.

Abstract: The present invention is an improved flow-metered pumping system using an air-backed diaphragm pump with load compensation. A variable motor speed controller is used to compensate for flow rate reduction caused by pressure effects. When the output pressure on the pump increases to a point where the load on the pump motor exceeds a specified threshold, the motor speed controller increases the speed of the motor to compensate for pressure induced diaphragm distortion losses and to achieve a substantially constant flow rate across a range of pump output pressures.

Abstract: An hydraulic actuator of a constant pressure fluidic supply system is disclosed in which a movable shuttle disposed within a generally cylindrical housing forms therewith a plurality of piston and cylinder assemblies. Displacement of the shuttle within the housing is governed substantially by opposing hydrodynamic and hydrostatic forces balanced so as to selectively isolate a pump control pressure switch from system pressure during periods of moderate to high consumption demand and provide communication therewith during periods of low to zero consumption demand. An hydropneumatic tank or a conventional diaphragm tank may be used in combination with the actuator to provide fluidic capacitance to the system. Additional system valving and pressure regulation may be incorporated as desired.

Abstract: Devices and methods for perfusing organs by controlling either the perfusion pressure or the perfusate flow rate. The operator may select either method of perfusion control. Also provided are devices and methods for perfusing multiple organs simultaneously on the same device.