Abstract: The invention relates to a mud suction unit having a suction element which is connected to a receiving container and has a motor for the generation of a suction flow and also has a discharging element attached to the receiving container.

Abstract: High-pressure cleaning device with an electric motor and a pump for conveying a cleaning fluid, with a plunger, which is displaceable by the cleaning fluid in dependence on its pressure or its flow rate, and with an electric switch, which is actuable by the plunger on its displacement, with electrical leads from the power source and to the windings of the electric motor disposed in the box, with devices attached to the box for fastening the box to the casing of the electric motor and/or pump, characterised in that the switch is disposed in the box, that the walls of the box have openings for the electrical leads, in which outwardly directed contacts are disposed, wherein at least one opening is configured as a multiple plug connection, that the box is fastened via a plug connection to the casing and that the multiple plug connections are disposed on the box in such a manner that at least one matching plug connection fastened to fit on the casing is necessarily connected when the box is fastened to the casing

Abstract: The invention provides a variable speed hydraulic pump designed to operate at a maximum horsepower throughout its pressure range by adjusting motor speed according to motor load parameters. In particular, the variable speed hydraulic pump includes a hydraulic pump unit coupled to a variable speed electric motor by a drive unit and to a hydraulic fluid tank for pressurizing and pumping hydraulic fluid when operated by the motor. A motor controller is electrically connected to the motor to supply drive signals to the motor based on electrical characteristics of the drive signals which are dependent on the load exerted on the motor. Suction from the load is provided by both the main pump and a bidirectional supercharging pump by reversing the direction of the motor and shifting a 4/3 valve to connect the main pump inlet to the load and its outlet to tank.

Abstract: A diaphragm pump comprises a two part casing formed of a front cover (10) and a back cover (12). A diaphragm plate (14) extends across the covers (10,12) and is secured therebetween when the covers (10,12) are fastened together. The diaphragm plate (14) has a plurality of similarly defined circular regions (16). The front cover (10) has substantially axially aligned inlet and outlet ports (18), each leading to mutually exclusive inlet and outlet chambers (22,24) respectively. A valve housing (26) is securable inside the front cover (10) and has defined therein an outlet dished valve seat (28) with a correspondingly concave resilient valve (30) seated therein. The outlet valve seat (28) has fluid passages therethrough. A plurality of inlet valve seats (34) is provided, equal in number to the number of regions, each being similarly dished and having a correspondingly concave resilient valve (36) seated therein. Each inlet valve seat (34) has fluid passages therethrough.

Abstract: The invention relates to an oil filter installation for cleaning or cleaning and dessication of the oil in a tap changer at a power transformer or a plunger core coil, wherein a measuring device for detecting the volume flow of the throughflowing oil is provided and the electric pump motor is influenced by way of an interposed frequency converter in accordance with the result of a comparison of this measured value with a target value.

Abstract: A digital pressure controller that utilizes a microprocessor provides for control of the speed of a fluid pump engine for the purpose of maintaining specified pressures at both the inlet and outlet of the pump. Based upon pressure sensor output, and computations based on multiple calibrations between pump speed and pressure, and between output voltage and pump speed, a pump drive mechanism speed is determined by the control logic of the microprocessor, which speed maintains at least one of the inlet and outlet pressures within a specified range. The microprocessor may determine the specific weight of the fluid being pumped in order to select the pump drive mechanism speed.

Abstract: A method and apparatus for controlling a compressor suitable for delivery of pressurized fluid to a pressurized fluid system, wherein the delivery of the pressurized fluid to the pressurized fluid system can be cycled on and off as a function of a temperature signal received from a temperature sensor. The delivery of pressurized fluid is turned off when the temperature signal exceeds a temperature limit value that is based on the backpressure caused by the pressurized fluid system. Time criteria can be superposed on the temperature limits for controlling the activation and deactivation of the compressor. A preferred area of application of the invention is in vehicle pneumatic suspension systems, including systems having multiple modes of operation.

Abstract: An air compressor includes: a tank portion for reserving compressed air used in a pneumatic tool; a compressed air generation portion for generating compressed air and supplying the compressed air to the tank portion; a drive portion including a motor for driving the compressed air generation portion; a control circuit portion for controlling the drive portion; and a pressure sensor for detecting pressure of the compressed air reserved in the tank portion. The control circuit portion includes a unit for controlling the rotational speed of the motor multistageously on the basis of a detection signal output from the pressure sensor.

Abstract: A compressed air system, wherein a decision to de-energize a compressor motor is made with consideration of the likely need for the operation of the compressor at a future point in time. A rate of pressure decay in an air reservoir may be extrapolated over a predetermined time period to predict the need for operation of the compressor within the time period. If operation of the compressor is predicted to be needed within the time period, the compressor is allowed to continue to run in an unloaded mode beyond a normal cool down period.

Abstract: Fluid pump control modes in a medical perfusion system include a Back Off Response Mode, a Flow Servo Mode, a Pressure Servo Mode, and a Master-Slave Servo Mode. In the Back Off Response Mode, pump's speed is decremented to a new speed when an excessive flow rate or pressure condition is detected. The new speed is maintained until an additional decrement is required or until the Back Off Response Mode is exited. In the Flow Servo Mode, a pump's speed is controlled to maintain a fluid flow rate indicated by a user as a setpoint. In the Pressure Servo Mode, a pump's speed is controlled to maintain a pressure indicated by the user as a setpoint. In the Master-Slave Servo Mode, a slave pump receives an indication of a master pump's speed, and the slave pump speed is controlled to maintain a specified percentage of the master pump's speed.

Abstract: The preferred drinking water pumping system is for receiving and storing drinking water from an outside source and for delivering the drinking water under pressure to a drinking water faucet or the like. A refillable drinking water storage tank provides the drinking water for a water pump that delivers the drinking water to a pressure tank for storing a variable amount of drinking water therein. Use of the drinking water faucet or the like reduces the volume of drinking water in the pressure tank that will be restored by the water pump as needed. The drinking water storage tank includes water level sensors to provide remote indication when the level of drinking water is low and to protect the water pump prior to the drinking water in the drinking water storage tank being expended.

Abstract: Pumping requirements for chromatograph applications are for constant flow at high and variable pressures and for accurate programmable control of liquid composition. A two-cylinder pump, pumping system, and associated controls provide an accurate, fixed flow rate. A low pressure gradient former controls composition. During the initial portion of the pumping stroke of a first piston in which fluid is being compressed due to its finite bulk modulus of elasticity its check valve remains closed, a second piston provides all the flow required at a fixed rotational speed. Then, once the first piston has reached its bottom dead center, the control system switches to a constant-pressure control mode, thereby maintaining the flow rate at a fixed value. Constant-pressure control is again switched off either when the second piston's discharge check valve closes, or when the second piston's inlet check valve opens, and pump control returns to fixed rotational speed.

Abstract: A switching reservoir which reserves brake fluid for reducing a pressure to a wheel cylinder is connected to a pressure decrease control valve and an intake port of a pump through a reservoir port, and connected to a M/C through a connection port. There are a ball valve and a rod below the ball valve inside the connection port. The rod moves up and down the ball valve integrally with a piston of the reservoir chamber. When an amount of the brake fluid in the reservoir chamber becomes less than a predetermined amount, the rod moves upward to cause the ball valve separates from a valve seat and is changed to be in an open sate, allowing the brake fluid to flow in from the M/C. Accordingly, the pump is always capable of sucking up the fluid, thereby preventing sharp increase of the rotational speed of the motor due to a sharp decrease in the pump load caused by an empty reservoir chamber and enabling driving of the motor with a duty control. Therefore, low noise and low pulse pressure can be achieved.

Abstract: A method and a system for detecting the speed of a pump motor of a hydraulic pump system are provided, in which pump system a pump is driven by a pump motor to deliver hydraulic fluid into a pump reservoir. In accordance with the present invention, a pressure signal representing the fluid-delivery activity of the pump is detected, and the pressure peaks within this pressure signal identified. The speed of the pump motor is determined on the basis of the frequency or the time intervals of these pressure peaks.

Abstract: A method is disclosed for determining the operating condition of a medical pump based on data derived from a pressure sensor and a position sensor. The pressure sensor generates pressure data by sensing the force on the pumping element. The position sensor generates position data by tracking the pumping cycle and determining the position of the pumping element. The pump pressure data and pump position data are processed and the calculated results compared with a pre-determined threshold value to determine the operating condition of the pump. The three main types of operating conditions of concern are the following: normal condition, where liquid is present and no leaks exist in pumping chamber; leak condition, where liquid is present but a leak exists in the pumping chamber; and air stroke condition, where the chamber contains some air.

Abstract: A hydraulic power system includes a reversible pump, a variable-speed servomotor for driving the pump, a pressure sensor for detecting load pressure, a detector for detecting the motor speed, signal command units for generating preprogrammed pressure and flow rate commands, a rotational speed controller and a signal processor. The signal processor preferentially outputs a speed command corresponding to the flow rate command by a limiter operation when the difference signal between the pressure command and the pressure detection signal is higher than a predetermined level, whereas it preferentially outputs a speed command corresponding to the difference signal when the difference signal is equal to or lower than said level. The rotational speed controller controls the magnitude of a driving current supplied to the servomotor by a closed loop on the basis of the speed command and the detected signal so that the speed of the servomotor corresponds to the speed command.

Abstract: An oil free screw compressor having a low-pressure stage compressor body and a high-pressure stage compressor body. Power of a motor driven by an inverter is transmitted to the compressor bodies through gears. A low-pressure stage blow-off two-way valve is provided in a pipe branching off midway an air pipe connecting between the high-pressure stage compressor body and the low-pressure stage compressor body, and a high-pressure stage blow-off two-way valve is provided in a pipe branching off from a discharge air pipe provided on a discharge side of the high-pressure stage compressor body. During no-load operation, a controller gives a command to the inverter to make the rotational speed of the motor a set lower limit rotational speed, and also gives an open command to the low-pressure stage blow-off two-way valve.

Abstract: A sump draining apparatus having an pressure transducer engaged in a receptacle that is in turn engaged in an open-ended collar of a housing. The receptacle and thus the pressure transducer is slideable in the axial direction into and out of the open-ended collar. The housing is generally cylindrical and contains a pump and motor, each of which has a generally cylindrical shape and is axially stacked in the housing. A cord having a vent and electrical leads for the pressure transducer is releasably engaged via a cord restraint at one end portion of the housing and the pressure transducer is releasably engaged in the receptacle in the open-ended collar at the other end of the housing. The receptacle and sensor may be removed, serviced, and/or replaced without the housing being opened and without the pump and motor being removed.

Abstract: A constant-pressure pump controller system for maintaining a substantially uniform discharge pressure of liquid output from a pump operated by an electric motor and where liquid is delivered to a plurality of simultaneously-operating downstream outlets. The system provides a pressure transducer for sensing discharge pressure from the pump, and includes a piston bearing a magnet for Hall effect interaction. To accomplish Hall effect sensing, an electric current carrier is situated to interact with the magnet for production of Hall voltage which is monitored by a voltage sensor in communication with a controller that regulates motor speed in accord with Hall-effect sensed need through pulse width modulation in response to the voltage value according to proportional integral derivative methodology. Finally, a pump input voltage sensor and regulator maintain a constant voltage output to the pump should voltage input be variable.

Abstract: A controller for controlling operating parameters associated with fluid flow, speed or pressure for a centrifugal pump for pumping fluid, wherein at least one sensor is coupled to the pump for generating a signal indicative of a sensed operating condition. The controller comprises a storage device for storing data indicative of at least one operating condition and a processor in communication with the sensor and operative to perform an algorithm utilizing the at least one sensor signal and the stored data indicative of the at least one operating condition to generate a control signal, wherein the control signal is indicative of a correction factor to be applied to the pump.

Abstract: The present invention relates to a process of utility conservation control methodology within a fluid pumping distribution system. With fluid flowing through a distribution grid, the pressure at any given point becomes a function of system flow. At a specific flow rate, the pressure at this point is a function of flow rate. This invention is a process that continuously adjusts the pressure requirement for the pumping system by varying the pump speed according to the system head curve details. This invention produces several benefits for a fluid distribution system including reducing utility costs and equipment aging.

Abstract: High-pressure cleaning device with an electric motor and a pump for conveying a cleaning fluid, with a plunger, which is displaceable by the cleaning fluid in dependence on its pressure or its flow rate, and with an electric switch, which is actuable by the plunger on its displacement, with electrical leads from the power source and to the windings of the electric motor disposed in the box, with devices attached to the box for fastening the box to the casing of the electric motor and/or pump, characterised in that the switch is disposed in the box, that the walls of the box have openings for the electrical leads, in which outwardly directed contacts are disposed, wherein at least one opening is configured as a multiple plug connection, that the box is fastened via a plug connection to the casing and that the multiple plug connections are disposed on the box in such a manner that at least one matching plug connection fastened to fit on the casing is necessarily connected when the box is fastened to the casing

Abstract: A hydraulic transmission pump assembly includes a pump adapted to provide fluid under pressure to predetermined components in a transmission, an electric motor operatively coupled to the pump, and a line pressure control device in electrical communication with the electric motor. The line pressure control device is operable to control the electric motor as to cause it to drive the pump when engine speeds are below a predetermined level such that the pump provides fluid at a predetermined volume and pressure to the transmission during this operating condition. A differential gear assembly is also included that is interposed between an engine and the electric motor, the differential gear assembly acting to drive both the pump and the electric motor when engine speeds are above the predetermined level such that the pump provides fluid at a predetermined volume and pressure to the transmission and the electric motor provides generated electricity.

Abstract: The present invention provides cavitation detection systems and methods employing a classifier for detecting, diagnosing and/or classifying cavitation in a pumping system. The classifier can be integral to tie cavitation detection system and/or operatively coupled to the cavitation system via a controller, diagnostic device and/or computer. Parameters such as flow, pressure and motor speed arc measured and/or estimated, and then provided to a classifier system Such systems include Bayesian, Fuzzy Set, nonlinear regression, neural networks and other training systems, for example The classifier system provides a signal indicative of the existence and extent of cavitation. An exemplary classification system is presented that delineates cavitation extent into one or more of the following categories: 0 (no cavitation), 1 (incipient cavitation), 2 (medium cavitation), 3 (fill cavitation) and 4 (surging cavitation).

Abstract: A pressure maintenance assembly for a domestic water well system. The assembly includes a pressure maintenance valve having an inlet side and an outlet side, a pressure tank in fluidic communication with the outlet side, and a calibrated bypass. When the valve is closed, the calibrated bypass provides fluidic communication between the inlet side and the outlet side. The size of the calibrated bypass and the pressure tank are adapted and constructed to permit a flow rate between the inlet side and the outlet side that will fill the pressure tank in a time interval at least as great as but less than twice the time required to pump a volume of water that will dissipate heat generated by the pump when it is turned on.

Abstract: The invention provides a variable speed hydraulic pump designed to operate at a maximum horsepower throughout its pressure range by adjusting motor speed according to motor load parameters. In particular, the variable speed hydraulic pump includes a hydraulic pump unit coupled to a variable speed electric motor by a drive unit and to a hydraulic fluid tank for pressurizing and pumping hydraulic fluid when operated by the motor. A motor controller is electrically connected to the motor to supply drive signals to the motor based on electrical characteristics of the drive signals which are dependent on the load exerted on the motor. Suction from the load is provided by both the main pump and a bidirectional supercharging pump by reversing the direction of the motor and shifting a 4/3 valve to connect the main pump inlet to the load and its outlet to tank.

Abstract: An oil free screw compressor having a low-pressure stage compressor body and a high-pressure stage compressor body. Power of a motor driven by an inverter is transmitted to the compressor bodies through gears. A low-pressure stage blow-off two-way valve is provided in a pipe branching off midway an air pipe connecting between the high-pressure stage compressor body and the low-pressure stage compressor body, and a high-pressure stage blow-off two-way valve is provided in a pipe branching off from a discharge air pipe provided on a discharge side of the high-pressure stage compressor body. During no-load operation, a controller gives a command to the inverter to make the rotational speed of the motor a set lower limit rotational speed, and also gives an open command to the low-pressure stage blow-off two-way valve.

Abstract: A method and apparatus which provides a pressure sensor and/or temperature sensor connected to the low pressure side of a refrigeration system, or the discharge line of a scroll compressor. When the scroll compressor rotates backward, the change of pressure or temperature immediately sends a signal to work with a time-delay relay and a normally closed relay to immediately cut off the electrical power supply to the compressor. Thus, causing the scroll compressor to stop rotating in the undesirable direction.

Abstract: A method and apparatus for controlling a variable displacement hydraulic pump having a swashplate pivotally attached to the pump. The method and apparatus includes determining a desired swashplate angle as a function of a power limit of the pump, determining an actual swashplate angle, determining a value of discharge pressure of the pump, moving a servo valve spool to a desired position as a function of the desired swashplate angle, the actual swashplate angle and the discharge pressure, and responsively moving the swashplate to the desired swashplate angle position.

Abstract: A system and method for compressing gas uses a hydraulic pump and a hydraulic accumulator to compress gases in gaseous form. The accumulator is divided into a hydraulic chamber and a pneumatic chamber. The pneumatic chamber of the accumulator can be pneumatically connected to a gas supply and a gas receptacle that needs filled. One-way directional flow valves are used to permit the flow of gas from the gas supply to the pneumatic chamber and from the pneumatic chamber to the gas receptacle, but to prevent the flow of gas in the opposite direction. A motor drives the hydraulic pump, which moves pressurized oil into the hydraulic chamber of the accumulator. The pressurized oil within the hydraulic chamber of the accumulator compresses the gas within the pneumatic chamber of the accumulator, forcing the into a tank or other receptacle that needs filled. The invention can be used to compress a variety of gases at different flow rates, volumes, and pressures.

Abstract: A constant-pressure pump controller system for maintaining a substantially uniform discharge pressure of liquid output from a pump operated by an electric motor and where liquid is delivered to a plurality of simultaneously-operating downstream outlets. The system provides a pressure transducer for sensing discharge pressure from the pump, and includes a piston bearing a magnet for Hall effect interaction. To accomplish Hall effect sensing, an electric current carrier is situated to interact with the magnet for production of Hall voltage which is monitored by a voltage sensor in communication with a controller that regulates motor speed in accord with Hall-effect sensed need through pulse width modulation in response to the voltage value according to proportional integral derivative methodology. Finally, a pump input voltage sensor and regulator maintain a constant voltage output to the pump should voltage input be variable.

Abstract: A pump assembly that has a control circuit and a pressure switch which control the operation of a pump motor. The motor drives a positive displacement pump that is coupled to a fluid system. The control circuit includes a pulse width modulator circuit. The control circuit is activated when a pressure switch senses that a line pressure of the fluid system is below a threshold value. The control circuit can either operate in a continuous mode to provide a constant signal to the motor, or a pulse regulating mode to provide a series of pulses to the motor. The pulses begin with a minimum width and gradually increase until a predetermined current limit has been attained, or the motor reaches a full speed with the control circuit in a continuous on state. The speed of the motor will then correspond to the flow demanded by the fluid system. The energy provided by the pulses is varied as a function of changes in peak current drawn by the motor. The peak current is sensed and used to determine the pulse width.

Abstract: A compressor that enables the increase of compression efficiency, the prevention of abnormal temperature rising in the discharge, and the reduction of power loss, includes a compressor body 11, an intake registration valve 12 in the inlet side, and a pressure sensor 18 provided in the discharge side to be able to detect pressure.

Abstract: A screw compressor system comprises a plurality of screw compressors the capacity of each of which is controlled by repeating load operation and no-load operation. Using a timer output corresponding to compressed gas consumption in a demander including gas consumption equipments, a parent controller determines the number of compressors to be operated among the plurality of compressors. Among the compressors determined to be operated, all compressors other than one are put in load operation. In accordance with a load factor of the excepted one screw compressor, the parent controller controls discharge pressure of each compressor. At this time, the control is made so that discharge pressure of the screw compressor system measured by a pressure gauge be lower than that upon the maximum gas consumption.

Abstract: An air compressor control system is constructed to include a motor, an accumulation tank, a pump, a pressure switch, a pressure control valve, and a micro-controller. When the pressure of the accumulation tank surpassed a predetermined high level, the pressure switch is off, thereby causing the micro-controller to open the pressure control valve for relieving forced air pressure and then to turn off the motor. When the pressure of the accumulation tank dropped below the predetermined low level, the pressure switch is switched on, thereby causing the micro-controller to provide power supply to the motor again and then to close the air pressure control valve for enabling forced air to be pumped into the accumulation tank by the pump after the motor has been fully started.

Abstract: A flow rate of unconnected first and second fluid flows is matched, such as, but not limited to, matching the flow rate of the replacement water stream with the waste water stream in kidney dialysis. The first and second flow paths are interconnected so substantially the same flow from a positive displacement pump in the first path encounters a flow-rate transducer in the second path. Transducer readings are taken for various values of the controllable pump speed of the pump. Then, the first and second flow paths are disconnected, a transducer reading is taken, and the flow rate of the fluid flow in the first flow path is controlled by controlling the pump speed using the value of the pump speed from the previous interconnected paths which corresponds to the value of the transducer reading from the previous interconnected paths which matches the transducer reading for the disconnected paths.

Abstract: A water supply system has its housing and pressure tank sized so that the pressure tank fits within the housing, thus avoiding the need for another separate opening in the ground for the pressure tank. With this arrangement, there is less work in installation of the system and in maintaining the system. The control box for the system can be in the housing near the top where it is accessible or can be separate. Preferably, the pump will be driven by a variable speed pump or a stop cycle valve will be used.

Abstract: An air compressor control system is constructed to include a motor, an accumulation tank, a pump, a pressure switch, a pressure control valve, and a micro-controller. When the pressure of the accumulation tank surpassed a predetermined high level, the pressure switch is off, thereby causing the micro-controller to open the pressure control valve for relieving forced air pressure and then to turn off the motor. When the pressure of the accumulation tank dropped below the predetermined low level, the pressure switch is switched on, thereby causing the micro-controller to provide power supply to the motor again and then to close the air pressure control valve for enabling forced air to be pumped into the accumulation tank by the pump after the motor has been fully started.

Abstract: A pump assembly for a pressurized water system includes a pressure sensitive switch (27) arranged to monitor the water pressure in a pipe (14) extending between a water delivery pump (13) and a tap (15), the switch (27) controlling operation of the pump (13) dependent upon pressure in the pipe (14). A timer switch (30) is disposed in series with the pressure sensitive switch (27), to inhibit pump operation other than for a limited period of time following triggering of the timer switch (30).

Abstract: An oil free screw compressor includes a low-pressure stage compressor body and a high-pressure stage compressor body. Power of a motor driven by an inverter is transmitted to the compressor bodies through gears. A low-pressure stage blow-off two-way valve is provided in a pipe branching off midway an air pipe connecting between the high-pressure stage compressor body and the low-pressure stage compressor body, and a high-pressure stage blow-off two-way valve is provided in a pipe branching off from a discharge air pipe provided on a discharge side of the high-pressure stage compressor body. During no-load operation, a controller gives a command to the inverter to make the rotational speed of the motor a set lower limit rotational speed, and also gives an open command to the low-pressure stage blow-off two-way valve.

Abstract: The injector of the invention serves for applying contrast media for X-ray or nuclear spin tomography and has a tube (3), as well as a roller pump (7) surrounded at least partially in peripheral direction by the tube (3) for transporting the fluid from a storage vessel (2) to a cannula. A pressure chamber (10) connected with the interior of the tube (3) through an opening (9) in the tube wall is provided, which has a component (11) adjustable under the effect of the fluid pressure, acting upon a pressure sensor (12).

Abstract: A portable air compressor includes a frame, a motor mounted to the frame, a storage tank coupled to the frame and a compression mechanism in communication with the storage tank. The motor drivingly engages the compression mechanism. The compressor includes a first regulator coupled to the storage tank for defining a first pressure at a first outlet port. A second regulator is coupled to the storage tank for defining a second pressure output at a second outlet port.

Abstract: A hydraulic transmission pump assembly including a pump adapted to provide fluid under pressure to predetermined components in a transmission, an electric motor operatively coupled to said pump, and a line pressure control device in electrical communication with said electric motor. The line pressure control device is operable to control the electric motor as to cause it to drive the pump when engine speeds are below a predetermined level such that the pump provides fluid at a predetermined volume and pressure to the transmission during this operating condition. A differential gear assembly is also included that is interposed between an engine and the electric motor, the differential gear assembly acting to drive both the pump and the electric motor when engine speeds are above the predetermined level such that the pump provides fluid at a predetermined volume and pressure to the transmission and the electric motor provides generated electricity.

Abstract: There is provided an autonomous inverter-driven hydraulic unit in which a command pressure and command flow rate do not need to be inputted from outside and a pressure and flow rate can be autonomously controlled without requiring any input signal wire. A target horsepower calculation unit 25 of a controller 11 judges which of a plurality of regions a point representing a present operating state belongs to and calculates a target horsepower represented by a point on a target pressure-flow rate characteristic line based on the present pressure and present flow rate. A comparison unit 28 calculates a deviation of this target horsepower and a present horsepower received from a present horsepower calculation unit 26, inputs a control signal representing this deviation to the inverter 3 and controls a rotational number of a variable-speed motor 2 so that the present horsepower coincides with the target horsepower.

Abstract: An injector for use in injecting a fluid in a medical injection procedure includes a drive having a motor to pressurize the fluid; a sensor to provide a measure of fluid pressure; and a pressure monitor in communication with the sensor and the drive to stop the motor using 4-quadrant control when the sensor communicates a measured pressure of at least a pressure hazard limit. The pressure monitor also limits power input to the motor to a power limit once the sensor communicates a measured pressure of at least a power limiting pressure. The power limiting pressure is below the pressure hazard limit.

Abstract: A radial flow turbomolecular vacuum pump includes a gas inlet, a gas outlet, a rotor, and a stator. The rotor includes a first rotor surface that is positioned in a substantially radial direction. A plurality of blades extends from the first rotor surface in a substantially axial direction. The stator includes a first stator surface that is positioned proximate to the first rotor surface in the substantially radial direction. A first and second plurality of vanes extend from the first stator surface and generally forms an annulus therebetween for receiving the first plurality of blades. A drive shaft is coupled to the rotor and positioned in the substantially axial direction. A motor is coupled to the drive shaft and rotates the rotor relative to the stator. The rotation of the rotor relative to the stator causes gas to be pumped from the gas inlet to the gas outlet in the substantially radial direction.

Abstract: A vacuum chamber (22) of a pneumatically operated servo unit (30) of a motor vehicle is subjected to vacuum by an electric suction pump (28). In order to monitor the vacuum chamber (22) and the electric suction pump (28), the invention proposes that a starting pressure in the vacuum chamber (22) be determined. In addition, after a certain time interval, an ending pressure in the vacuum chamber (22) is determined. Furthermore, the difference between the ending pressure and the starting pressure is calculated and compared to a limit value. If this difference falls below the limit value, a signal is generated, in particular a warning and/or alarm signal.

Abstract: An electronic pressure sensor is incorporated into a discharge pressure portion of a compressor. If the pressure sensor indicates that the discharge pressure exceeds a maximum value, the operation of the compressor motor is stopped. The pressure sensor preferably sends an electronic signal to a microprocessor such that the pressure can be compared to a predetermined maximum value. The pressure sensor includes a transducer to change the sensed pressure to a voltage value. The microprocessor communicates with a first switch, which may be a triac switch, and which stops operation of the compressor motor should an undesirably high value be detected. In addition, a second switch communicates with a comparing circuit which ensures the voltage from the pressure sensor is between a minimum and maximum value. The purpose of the comparing circuit is to ensure proper operation of the pressure sensor and its associated circuit.

Abstract: An electronic control system dynamically varies the output capacity of a compressor by controlling plural valves associated with the compressor to provide pressurized air to a distribution system at an appropriate rate. The control system operates in any of three modes for standalone operation, including continuous run, auto/dual pressure band, and target pressure modes. In the first two modes, pressure bands are dynamically calculated based on load and unload values entered by an operator. These electronic control systems can also be connected in a peer-to-peer network to coordinate control of up to 16 compressors feeding the same distribution system, so as to maintain a desired target pressure in the system. A modem connected to the system supports remote diagnostics, monitoring, and control. Specialized startup, operating, and shutdown diagnostic algorithms prevent damage to the compressor and avert unsafe operating conditions.

Abstract: A method and system for determining pump cavitation is disclosed. In accordance with the principle of the invention, changes in dynamic fluid pressure within a pump are monitored and compared to a determined cavitation alarm pressure. The determined cavitation pressure is determined as a known percentage of a known non-cavitation pressure. Fluid cavitation is determined when the change in dynamic fluid pressure falls below the determined cavitation alarm pressure. In a further aspect of the invention, a remaining mechanical seal operational life can be determined by maintaining a total time of fluid cavitation and reducing the expected life by the known operational time of the pump and the time the pump is in cavitation.