Abstract: A method and apparatus for achieving constant air flow rate economically utilizes an induction blower motor with control settings determining the motor excitation voltage. A memory stores, for a variety of motor speeds, a graph of the speeds plotted against a proportionality constant of flow rate to fan speed for the selected motor system on one axis and motor control settings on the other axis. The only monitoring necessary to achieve the constant flow rate is thus the sensing of fan rotational speed. The measured fan speed is compared against the proportionality constant needed for the selected constant air flow rate and a motor excitation voltage is derived to achieve that proportionality constant. When the system load changes significantly, thereby causing significant fan speed change, a cascaded control loop is used whereby the speed changed induced by each control voltage adjustment is monitored until the desired constant flow rate is again attained at the new load level.

Abstract: Disclosure is made of a method for electronic polar attenuation of torque profile for positive displacement pumps by a processor where the attenuated torque profile is compared with the shaft displacement angle of the pump input shaft. The processor then signals a motor to power a pump with the result of pumping at a constant pressure at the full range of the designed system flow volume. In addition to the attenuated torque profile, the processor can also account for the response time of the pump drive, the motor inductive reactance, system inertia, application characteristics of the pump, and regenerative energy during deceleration of the pump.

Abstract: There is provided a magnetically levitated apparatus wherein an impeller has one side supported by an electromagnet and the other side supported and magnetically levitated by an attractive force created between a permanent magnet and a permanent magnet of a motor rotor rotated by a motor stator to rotate the impeller and a magnetic bearing sensor provides an output which is in turn rectified and thus shifted to have a gain adjusted and subsequently a notch filter removes a carrier wave frequency component used in the magnetic bearing sensor, to prevent a PID compensator from causing voltage saturation attributed to high frequency noise.

Abstract: The invention relates to a method for operating a dosing pump, the pump being driven by an asynchronous motor, comprising a drive which converts the motor revolutions into pump strokes of a defined stroke frequency. The pump strokes are comprised of a pump suction stroke and of a pump delivery stroke. Pump strokes are continuously carried out during a dosing phase. The aim of the invention is to provide a solution concerning a dosing pump having an asynchronous motor drive, a frequency converter thereto, and a control unit which interacts therewith in which the dosing behavior is improved during the operation of dosing pumps having an asynchronous motor drive.

Abstract: A vacuum system comprises, as an integral assembly, a vacuum pump with drive motor, a purge valve, a roughing valve and an electronic control module. A cryogenic vacuum pump and a turbomolecular vacuum pump are disclosed. The control module has a programmed processor for controlling the motor and valves and is user programmable for establishing specific control sequences. The integral electronic control module is removable from the assembly and is connected to the other devices through a common connector assembly. In the turbomolecular pump system proper introduction of a purge gas through the purge valve is detected by detecting the current load on the pump drive or by detecting foreline pressure. To test the purge gas status, the purge valve may be closed and then opened as drive current or pressure is monitored. After power failure, the controller will continue normal drive of the turbomolecular pump so long as the speed of the pump has remained above a threshold value.

Abstract: A scroll compressor is provided with a thermostat selectively closing when predetermined temperatures are reached to deliver current to a heater associated with a motor protector switch. The thermostat is able to more quickly close in response to undesirable conditions in the compressor, than would be the case with the motor protector switch typically found at the motor. The circuit associated with the motor protector switch preferably includes at least two heaters, with the normal heater associated with the power lines leading to the motor performing its normal function. The thermostat is preferably associated with an auxiliary heater. In another feature, a heater is preferably formed with a thick film technology directly onto an insulator element within the motor protector body.

Abstract: An apparatus for controlling an operation of a linear compressor includes: a sensorless circuit unit for detecting a current and a voltage applied to a linear compressor and outputting a work operation value corresponding to them; a stroke controller for receiving the work operation value and outputting a switching control signal corresponding to a variation amount of the work operation value; and an electric circuit unit for receiving the switching control signal from the stroke controller and outputting a certain voltage to the linear compressor, accordingly, a TDC of the piston in consideration of an error due to the nonlinear characteristic can be controlled, and thus, an operation efficiency of the linear compressor can be improved.

Abstract: In an apparatus and a method for controlling operation of a linear compressor using a pattern recognition for operating a compressor as an optimum efficiency by recognizing a trace about a graph about relation between a current and a displacement as a pattern and sensing variation of the pattern, the apparatus for controlling operation of the linear compressor using a pattern recognition includes a displacement calculating unit calculating a displacement by being inputted the current detected in the current detecting unit and the voltage detected in the voltage detecting unit, a pattern recognition unit being inputted the displacement outputted from the displacement calculating unit and the current outputted from the current detecting unit and detecting a pattern by using a trace corresponded to the displacement and the current, a stroke controlling unit being inputted a pattern from the pattern recognition unit and outputting a switching control signal according to the inputted pattern, and an electric circu

Abstract: A filling machine with a rotary peristaltic dispenser that compensates for the nonlinear flow rate characteristic of the dispenser to increase product fill accuracy is disclosed. A computer processor including associated electronic circuitry and programs is provided for defining, digitizing and storing the real pulsating flow rate characteristic of the dispenser. In order to ensure a precise delivery of the filled product, the computer calculates the angular rotation of the rotor needed to deliver the desired fill weight for each filling cycle. The angular rotation needed to maintain a uniform fill weight is generally different for each filling cycle. The current position of the rotor is first established prior to each filling cycle and then located on a stored look-up table containing the flow rate characteristic as a starting point for digital integration of the characteristic over the angular distance of the driver.

Abstract: An impeller has one surface with a soft magnetic member arranged closer to an inner diameter thereof, opposite an electromagnet, the impeller is provided with a permanent magnet arranged closer to an outer diameter thereof, opposite a permanent magnet of a rotor, and the impeller has the other surface provided with a ferromagnetic body, opposite a permanent magnet of a casing, thereby magnetically levitating the impeller, and allowing a motor stator to rotate a motor rotor to rotate the impeller.

Abstract: A blower supplies compressed air to a predetermined place. The blower is provided with a plurality of compressors, a common air tank for storing compressed air supplied from the compressors, a changeover valve for switching the compressed air taken in from the air tank between a first supply state and a second supply state, and a controller for controlling operations of the compressors and the switching operation of the changeover valve. The controller can select one operation pattern from among a plurality of operation patterns determined by combinations between the compressors and the changeover valve.

Abstract: A water distributing installation controller includes water pumps for supplying clear water from a filtration plant to a distributing reservoir, a level gauge for measuring the water level of the distributing reservoir, a first flow meter for measuring the water supply directed thereto, a second flow meter for measuring the water delivery directed to a distributing area, a pumps-number control part for controlling the number of pumps operated, and a short-term demand prediction part for providing short-term demand prediction data on the water delivery to the pumps-number control part at the request thereof.

Abstract: Electrical isolation method and assembly that protects a pump-off controller 31 as used for controlling the pumping of a subterranean well, from lightning and transient electrical power surges by electrically isolating the pump-off controller 31, the isolation assembly including fiber optic cables 17, 18, signal converters to convert electrical signals to optical signals 25, 33, signal converters to convert optical signals to electrical signals 32, 19 and a solar panel 35 to power the pump-off controller 31. Components of the fiber optic and control assembly may also be electrically protected from lightning and electrical power transients by including an isolation transformer 53, components to drive the isolation transformer 53, metal oxide varisters, fuses and other protection devices. Signals from the pump-off controller 31 may be used to stop/start a prime mover 45 for a pumping unit 46, or regulate the speed of the prime mover 45.

Abstract: An infusion device with a disposable administration set which is inexpensive to manufacture which set can be slidably inserted and removed from a housing, and which is programmable, is provided. 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.

Abstract: The present invention is an injection system including an injection device. The injection device includes a pumping chamber and an electrically operated device associated with the pumping chamber which, when energized, is capable of providing a rapid increase in localized fluid pressure in said pumping chamber without reciprocating a piston in a cylinder bore. A discharge port associated with the pumping chamber permits discharging of fluid displaced by the localized pressure increase. The injection system includes a circuit providing an energizing voltage to the electrically operated device, and a control for changing at least one characteristic of the energizing voltage selected from the group consisting of: the peak energizing voltage, the rate at which said energizing voltage increases, the rate at which said energizing voltage decreases, the duration of energization, and the frequency of energization.

Abstract: An apparatus for controlling an operation of a linear compressor by which an instablel phenomenon caused due to a characteristics deviation of parts of a compressor is corrected to stabilize the operation of the system, thereby accomplishing an optimal operation. Also, when the tuning instability occurs due to the characteristic deviation and the assembly deviation of the mechanic unit of the compressor, and the parts deviation in the control circuit such as the sensorless stroke estimator, the compressor deviation is corrected by using a relative coordinate value. And, while the linear compressor is being operated with the stroke command value according to the cooling mode, in case that the current stroke is in an unstable state, the stroke command value is lowered down as much as a predetermined value, with which the linear compressor is operated for a predetermined time. Then, when a predetermined time lapses, it is operated with the original stroke command value, thereby evading the instablel state.

Abstract: A control circuit of a solenoid actuated pump includes an energizing means for energizing a solenoid of the solenoid actuated pump, a detecting means for detecting the electrical energy of a power supply for supplying the electrical energy to the energizing means, and a processing unit for comparing the value of the electrical energy detected by the detecting means with a predetermined value to be supplied to the solenoid and supplying a control signal to the energizing means so as to adjust the detected value of the electrical energy to the predetermined value.

Abstract: A cooling system for cooling components of a computer is provided. The cooling system includes a DC fan which operates at a speed which is substantially proportional to the voltage that is applied to the fan. A zener diode voltage divider is connected in series between a voltage source and a first input of the fan. The second input of the fan is connected to a reference voltage source. A switch is also connected in series between the voltage source and the first voltage input of the fan so as to be connected in parallel with the zener diode voltage divider. When the switch is in a first position, the voltage produced by the voltage source is applied directly to the fan allowing the fan to operate at a first speed. When the switch is in a second position, the voltage from the voltage source is applied to the first input of the fan through the zener diode such that the first input of the fan receives a second voltage that is less than the first voltage thereby causing the fan to operate at a second speed.

Abstract: An apparatus and a method are provided for protecting a vacuum pump from being overloaded while maintaining the vacuum condition. A pump-protecting device comprises a power detector for detecting power consumption of a motor for driving a vacuum pump as a load received by the motor, and a control means for decreasing the speed of revolution of the motor when the value of power consumption detected by the power detector is equal to or greater than a predetermined value.

Abstract: A two-stage reciprocating compressor is provided. The compressor includes a reversible motor that rotates a crankshaft. The crankshaft is connected to a piston by a mechanical system. The mechanical system drives the piston at a full stroke between a bottom position and a top dead center position when the motor is operated in a forward direction. The mechanical system drives the piston at a reduced stroke between an intermediate position and the top dead center position when the motor is operated in the reverse direction. The compressor also includes a control for selectively operating the motor in either the forward direction at a first preselected, fixed speed or in the reverse direction at a second preselected fixed speed.

Abstract: A stepper motor controller and method for controlling the motion of a stepper motor by selectively energizing the motor's windings so that the current level in the windings match a desired current profile. The motor controller comprises a master logic device, preferably a microprocessor or microcontroller, which is programmed with logic for issuing control signals corresponding to the sequence with which the windings of the stepper motor are energized and the desired current profile. A portion of the control signals are received by a slaved logic device, which is programmed with logic for generating ramp command signals corresponding to the desired current profile. The slaved logic device produces a ramp command signal that is received by a digital potentiometer, which preferably includes an up/down counter. The output signal produced by the digital potentiometer corresponds to a current count value of the up/down counter, and it is controlled by the ramp command signals.

Abstract: A method of controlling a reciprocating compressor comprising of starting the reciprocating compressor at a minimum speed in which a frequency of 45-52 Hz is applied, operating the reciprocating compressor at a frequency of 52˜60 Hz and operating the reciprocating compressor at a predetermined rotational speed. Therefore, an optimum amount of lubricating oil is supplied to a sliding part of the reciprocating compressor so that the reliability of parts thereof is secured.

Abstract: An output control apparatus for a linear compressor and a method of the same are disclosed. In the conventional art, when controlling an output of the linear compressor using a stroke, it is possible to implement a constant stroke. However, since the intermediate position of the piston is varied, it is impossible to constantly implement a top dead point. Therefore, an output control of the linear compressor is difficult, and a higher efficiency is not easily implemented. In addition, there is a problem for constantly controlling an output of the linear compressor.

Abstract: A control circuit for vibrating compressors for converting d-c voltage into a-c voltage to supply a-c voltage to a vibrating compressor (1) comprising a MOS-FET transistor (2) for driving the vibrating compressor (1), a timer IC for generating pulses to switch the MOS-FET transistor (2), a timer forced operation circuit for forcibly reversing the output of the timer IC at a timing at which a counter-electromotive voltage generated by the vibrating compressor (1) during the OFF period of the MOS-FET transistor (2) is restored in the vicinity of 0 volts, a driver for driving the MOS-FET transistor (2) based on the output of the timer IC, and a pulse width changing circuit (9) for detecting an input voltage input into the vibrating compressor (1) and lowering the input voltage to the vibrating compressor (1) by changing the pulse width of output pulses of the timer IC when the input voltage is higher than a predetermined voltage.

Abstract: A fuel injection system is provided with an interior pumping chamber (94) which is connected to a fuel inlet (98). A pumping element (90) is provided with piezoelectric elements (124) which are interspaced between electrodes (126, 128). The pumping element (90) is electrically connected to an ECU (58). Activation of the piezoelectric elements causes pumping element (90) to expand and thereby impart pressure from a pressure surface (112) which extends into the pumping chamber (94). Fuel in the pressure chamber, as a result of the piezoelectric elements is pushed from the pressure chamber and through an injection valve (116).The applicants are reminded that formal drawings are now required. Further, as noted in the Office Action of Dec. 16, 1999, in FIG. 2, numeral 124 should be changed to indicate mounting plate 121. On drawing sheet 6, FIG. 6a and FIG. 6b should be indicated.

Abstract: An air compressor includes a stator, which includes an inlet and an outlet and defines a substantially cylindrical bore, and a rotor eccentrically rotatably mounted in the bore. The rotor is connected to be rotated by a three-phase asynchronous electric motor of pole amplitude modulated type which is switchable between low speed six pole operation and high speed four pole operation under the control of a controller. A pressure sensor communicates with the compressor outlet and is connected to the controller which is arranged to produce a first signal when the compressor discharge pressure falls below a first threshold value and a second signal when this pressure rises above a second threshold value.

Abstract: An air compressor system having an unloader valve which is directly mechanically activated by an air compressor motor's centrifugal mechanism to allow the motor to reach a predetermined speed before a load is applied is disclosed. The unloader valve is mounted directly on an end flange of the motor and communicates with an outlet conduit of the air compressor to allow the compressed air from the air compressor to vent to atmosphere until the motor reaches the predetermined speed.

Abstract: For a refrigerant compressor having two capacities, a camming structure operable in different manners depending on direction of crankshaft rotation, to achieve each capacity while providing top dead center piston operation thru the use of a circular cam bushing which is eccentrically, rotatably mounted on the crankshaft eccentric and within the connecting rod bearing wherein the combined eccentricities of the bushing and the eccentric equal the primary stroke of the piston. A first stop mechanism is provided for stabilizing the bushing on the eccentric upon rotation of the crankshaft in one direction whereby the eccentricities of the eccentric and bushing become aligned and remain so during synchronous rotational orbiting motion of the eccentric and bushing during rotation of the crankshaft for producing full stroke and full capacity.

Abstract: The present invention provides a system and a method for controlling and detecting faults in a pump system for use in a gas detection device. The system comprises a power source and a switch in operative or electrical connection with the power source. The system further comprises a pump motor in operative connection with the switch such that the pump motor receives energy from the power source when the switch in a first state, and the pump motor does not receive energy from the power source when the switch in a second state. The system preferably also comprises regeneration circuitry in operative connection with the pump motor. The regeneration circuitry operates to redirect energy produced from momentum of the pump motor while the switch is in the second state back to the pump motor. Transmitting circuitry is preferably provided to transmit a motor signal proportional to the speed of the pump motor during the second state of the switch.

Abstract: There is provided a cooling system of a semiconductor testing device wherein the number of revolutions of a fan is controlled so as to obtain proper air-flow corresponding to a heating value for every operating mode of the measuring unit, thereby preventing power from being wasted. The cooling system of a semiconductor testing device comprises a fan for cooling the measuring unit by the rotation of a DC motor, a temperature sensor for measuring a temperature of the measuring unit which is cooled by the fan, and a temperature control/power supply unit for supervising temperature information which is supplied from the temperature sensor and executing optimum control of the number of revolutions of the fan corresponding to a heating value of the measuring unit for every operating mode.

Abstract: A high speed compressor (10) includes a gear box (11), two compressing units (12, 13) supported on opposite side walls of the gear box (11) and a bull gear (32) rotatably placed in the gear box (11). Each compressing unit includes a scroll (15, 16) and an impeller (18, 19) rotatably housed in the scroll (15, 16). The impellers (18, 19) share an impeller shaft (22) extending into the gear box (11). A pinion gear (23) is mounted on the impeller shaft (22) such that it engages with the bull gear (32). A drive shaft (30) extends from the bull gear (32) out of the gear box (11) along a center axis of the gear box (11). An induction motor (35) is connected with the drive shaft (30) for causing the impellers (18, 19) to rotate by way of the bull gear (32) and the pinion gear (23). An inverter (40) is connected with the induction motor (35) at its one end and with a commercial power source (43) at the other end for converting an A.C. power from the commercial power source (43) into an A.C.

Abstract: A fluid pump speed controller apparatus for ensuring adequate system fluid pressure while minimizing energy consumption. The fluid pump speed controller has an adjustable frequency motor drive and control circuits to vary fluid pump motor speeds based on system fluid demand, monitored by a sensor. The control circuits set the pump speed, based on input from the sensor. The control circuits also set parameters in the control circuit logic, and are capable of self calibration and controlling multiple fluid pumps.

Abstract: In a linear compressor driving apparatus, a position instructing portion (31) outputs a position instruction value Pref of a piston in accordance with an equation A*sin .omega.t. A position control portion (33) calculates a speed instruction value Vref by multiplying difference between position instruction value Pref and position present value Pnow by a constant Gv. A speed control portion (35) calculates a current instruction value Iref by multiplying a difference between speed instruction value Vref and speed present value Vnow by a constant Gi. A current control portion (37) controls a power source (3) so that current present value Inow becomes equal to the current instruction value Iref. Phase control portion (38) adjusts .omega. and Gi so as to eliminate phase difference between speed present value Vnow and current instruction value Iref. Since thrust of linear motor can be directly and appropriately controlled in accordance with the load condition, high efficiency is obtained.

Abstract: A linear compressor operating apparatus includes a rectifying and filtering unit for converting an alternating current into a direct current, an inverter for inverting the direct current outputted from the rectifying and filtering unit into a desired frequency alternating current for operating a linear compressor in accordance with the alternating current outputted from the inverter, a position sensor for detecting a position of a piston of the linear compressor and outputting a position signal in accordance with said detection, a current detector for detecting the current running through the linear compressor, and a controller for receiving a current signal outputted from the current detector and a position signal outputted from the position sensor and outputting a pulse width modulating signal to control the inverter.

Abstract: A constant pressure variable speed inverter control booster pump system including a control unit, an inverter controlled by the control unit to change output frequency subject to the pressure of the water supply pipe, a motor controlled by the inverter to drive a pump, a pressure transmitter installed to detect the pressure in the water supply pipe, and a pump controlled by the motor to pump water through the water supply pipe, wherein the control unit detects the change of pressure in the water supply pipe, and provides an analog signal DC 0V-10V to the inverter subject to the detection result, causing the inverter to change output frequency to the motor, so as to control the speed of the motor under a constant range.

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 screw type dry vacuum pump having dual shafts is disclosed, whereby the process gas is transported through three compartments, a gas admittance pump section, a central drive motor section, and a gas discharge pump section. By placing the drive motor in the center of the pump, it becomes possible to design a pump having the dual shafts supported only at one end, thus enabling to mount the rotors at the free ends of the pump which are closed with end plates which can be removed easily for servicing the pump sections. Synchronous operation of the dual shaft pump by magnetic coupling enables to lower power consumption and to extend the range of operable pressures.

Abstract: A downhole rotary pump driven by a polished rod and a string of sucker rods from the earth's surface by a variable or fixed frequency, three phase electric motor, is controlled by measurements of power consumed by the electric motor and by measurements of the rotary speed of the polished rod, the combinations of such measurements being indicative of the torque exerted on the polished rod. Determinations of such torque being either within or outside of predetermined upper and lower torque limits are used to either maintain the rotary speed of the downhole pump, or to vary the rotary speed of the downhole pump, or alternatively, to completely shutdown the downhole pump. Power generated by the motor is monitored and the measured value of power may also be used to terminate motor operation when a low power limit is exceeded.

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 method of stopping a scroll compressor that is driven by a 3-phase dc motor having 3-phase exciter windings is provided. The motor is energized by a 3-phase dc power that is produced from a dc power source through an electronic switching circuit. The switching circuit has three pairs of bridge-connected switching transistors whose switchings are individually controlled by a switching controller. One of each pair of the switching transistors belongs to a first transistor group that is connected to a positive terminal of the dc power source and the other belongs to a second transistor group that is connected to a negative terminal of the dc power source.

Abstract: A fluid compressor has a sealed case, an electric motor section, and a compression section. Both sections are provided in the sealed case, with their axes extending substantially horizontally. The sealed case is filled with lubricant. At the start of the compressor, the rotational speed N of the electric motor section is gradually increased, but maintained at least once at a prescribed value for a predetermined period. At the stop of the compressor, the rotational speed N is gradually decreased, but maintained at least once at a prescribed value for a predetermined period.

Abstract: The invention relates to a process and to a device for regulating a multiphase pumping assembly that includes notably at least one multiphase pump (1), a device (6) for determining a parameter representative of a working instability of multiphase pump (1) and at least one programmed processing assembly (7) allowing to store at least the determined parameter and initial parameter values, and to compute the new value of the speed of said multiphase pump in order to bring the working point of the pump back into its operating range.

Abstract: A dual speed fuel delivery system for an internal combustion engine in an automotive vehicle includes a fuel pump, a dropping resistor connected to the fuel pump for reducing the voltage required to drive the fuel pump, and a controller for determining an optimum transition point between one of a relatively high and low speed fuel pump operation so that a controlled amount of fuel is delivered to the engine. The controller calculates fuel pressure increase across the fuel pump, determines the minimum fuel pump voltage necessary to drive the fuel pump such that a predetermined amount of fuel is supplied to the engine and determines the current draw of the fuel pump. The controller then calculates the voltage drop across the dropping resistor and compares the resulting voltage with the minimum fuel pump voltage. The controller then selectively by-passes the dropping resistor based on this comparison.

Abstract: An evacuating apparatus includes a first pump section disposed on a suction opening side, a second pump section for exhausting a smaller amount of gas than the first pump section, the second pump being disposed in an exhaust opening side, a plurality of rotors accommodated in a housing, bearings for supporting rotation of the rotors, a suction opening for drawing fluid and a first exhaust opening thereof both formed on the housing, and a plurality of motors for driving the rotors. In the apparatus, the first pump section is a pump of positive displacement type formed by utilizing a volume change of a space defined by the rotors and the housing, and the second pump section is a viscous-type pump formed by utilizing a relatively moving surface formed in a small gap defined between the rotors and the housing.

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 rotary blood pump includes a pump housing for receiving a flow straightener, a rotor mounted on rotor bearings and having an inducer portion and an impeller portion, and a diffuser. The entrance angle, outlet angle, axial and radial clearances of blades associated with the flow straightener, inducer portion, impeller portion and diffuser are optimized to minimize hemolysis while maintaining pump efficiency. The rotor bearing includes a bearing chamber that is filled with cross-linked blood or other bio-compatible material. A back emf integrated circuit regulates rotor operation and a microcomputer may be used to control one or more back emf integrated circuits. A plurality of magnets are disposed in each of a plurality of impeller blades with a small air gap. A stator may be axially adjusted on the pump housing to absorb bearing load and maximize pump efficiency.

Abstract: A power supply for vibrating compressors having an inverter for converting direct current (d-c) into alternating current (a-c). The power supply includes a d-c power source section for applying d-c voltage to the inverter, a current detecting apparatures for detecting a current flowing in the vibrating compressor, a control section having a frequency following circuit for generating a frequency following the resonance frequency of the vibrating compressor on the basis of a current detected by the current detecting apparatures, and an inverter control circuit for controlling the inverter with the frequency generated by the frequency following circuit. The vibrating compressor is driven by an a-c voltage of the frequency agreeing with the resonance frequency of the vibrating compressor.

Abstract: In a compressor for adjusting a cooling power such that a piston integrally formed with an oscillator according to the oscillation of said oscillator adjusts the amount of refrigerant absorbed into a cylinder, a cooling power controller for the compressor which can control the cooling power by varying the power itself to change the operation state of the compressor for controlling the temperature of a refrigerator or an air conditioner, includes a power source for varying input alternate power to output the same through a plurality of secondary ports, an applied voltage controller for selecting the secondary port voltage of the power source to control the cooling power of the compressor, and a comparator for comparing a predetermined temperature with the actual temperature of an heat exchanger to control the applied voltage controller.

Abstract: A gaseous fuel compression and control system for gas turbine engine (30) comprises a screw compressor (10) driven by an electric motor (11) for feeding gaseous fuel to the gas turbine engine, and a modulating device (12) for modulating the rotational speed of the motor by controlling the frequency of electric power to the motor in response to sensed output power of the gas turbine engine.

Abstract: A lubricating system for a machine such as a two-cycle internal combustion engine including a reciprocating pump that pumps a finite amount of lubricant during a single pumping stroke and a stepper motor for operating the pump through incremental phases of movement each less than a stroke. The lubricant requirements of the machine are determined and the driving increments are adjusted so as to provide a pumping stroke when the lubricant consumption of the machine reaches the output of the pump. Various arrangements of stepper motors and control arrangements are disclosed for controlling the amount and timing of the lubricate delivery.