Abstract: A method and apparatus for regulating the vacuum supply to calibration tools which include at least one dry calibration tool and at least one calibration bath, wherein at least one vacuum pump is brought into contact with a calibration tool in order to extract air from the calibration tool, the pressure in the tool being regulated to a target value by means of a control valve. Several vacuum pumps extract air from a common pressurized container, and the air is extracted from at least one dry calibration tool by a first control valve in the common pressurized container and in addition the air is extracted from at least one calibration bath by a second control valve in the common pressurized container.

Abstract: A vehicle control apparatus includes an input member; a driving force transmission mechanism that transmits a rotational driving force of the input member to an output member; a mechanical pump that operates by using the rotational driving force of the input member; an electric pump that operates when a rotational speed of the mechanical pump is less than a predetermined operation threshold; an oil pressure control apparatus that performs control operations for the driving force transmission mechanism by supplying operating oil, which is supplied from the mechanical pump and the electric pump, to the driving force transmission mechanism; and a controller that detects a state of the electric pump.

Abstract: The present invention discloses a system of energy-efficient and constant-pressure fluid-transport machines coupled in parallel, which can flexibly and massively provide gas and water to every fabrication unit. The system of the present invention comprises: variable-frequency centrifugal fluid-transport machines, pressure gauges, power meters, flow meters, and controllers. The performance curves of the abovementioned system of fluid-transport machines coupled in parallel and the system impedance curves of the loads are analyzed theoretically and built in the controllers together with the equal-efficiency curves provided by the manufacturer. When the system is operating, the data detected by the pressure gauges, power meters, and flow meters are compared with the built-in data to obtain the optimal energy-efficient conditions as the operational criteria of the system of the present invention.

Abstract: A fan array fan section in an air-handling system includes a plurality of fan units arranged in a fan array and positioned within an air-handling compartment. One preferred embodiment may include an array controller programmed to operate the plurality of fan units at peak efficiency. The plurality of fan units may be arranged in a true array configuration, a spaced pattern array configuration, a checker board array configuration, rows slightly offset array configuration, columns slightly offset array configuration, or a staggered array configuration.

Abstract: A system for cancelling or attenuating noise in at least two positive displacement compressors proximately located from each other for use with a heating or cooling system. A lead compressor and a lag compressor have a controllable rotational speed and phase of operation. A controller selectably controls the rotational speed and the phase of operation of each of the compressors. The controller controls the rotational speed of the compressors at substantially the same speed for each compressor, with a phase-lock loop and a comparator circuit for each compressor. The controller controls the phase of operation of the compressors through an oscillator so that the lead and lag compressor pressure pulses are spaced between successive outlet pressure pulses to effectively double the combined pulsation frequency for noise attenuation.

Abstract: A brushless fan motor, in which cooling effect on a stator may be enhanced, is provided. A center through hole is formed in a center of a bottom wall portion of a first brushless fan motor. Vane portions are formed on an inner wall portion of the brushless fan motor and are formed into a shape which allows ambient air to be drawn in through the center through hole. Through holes are formed in an end plate portion of the first brushless fan motor in order to introduce the ambient air, which has been drawn in through the center through hole, inside a rotor cover.

Abstract: A radiator blower, in particular for motor vehicles, is indicated that comprises a plurality of individual fans (11, 12), each having an electrical drive motor (13, 14), and a plurality of switches (S1, S2, S3), each capable of being switched over into two positions, by means of which the drive motors (13, 14) are capable of being turned on and back off individually or in a series or parallel connection. To prevent disturbing noises from developing when the individual fan (11, 12) comes to rest after being turned off, when the operating drive motor or motors (13, 14) is/are turned off, an electronic control unit (20) forces the switches (S1, S2, S3)—at least temporarily—over into switch positions that bring about a short-circuiting of the turned-off drive motor or motors (FIG. 1).

Abstract: A fan array fan section in an air-handling system includes a plurality of fan units arranged in a fan array and positioned within an air-handling compartment. One preferred embodiment may include an array controller programmed to operate the plurality of fan units at peak efficiency. The plurality of fan units may be arranged in a true array configuration, a spaced pattern array configuration, a checker board array configuration, rows slightly offset array configuration, columns slightly offset array configuration, or a staggered array configuration.

Abstract: A multi-chamber installation (1) treats objects under vacuum. An evacuation system (5) is connected to a plurality of chambers (2, 3, 4). To reduce the complexity of the evacuation process, a forepump (5) has several stages (11, 12, 13). Each of said stages is connected to one of the chambers (2, 3, 4).

Abstract: A fan array fan section in an air-handling system includes a plurality of fan units arranged in a fan array and positioned within an air-handling compartment. One preferred embodiment may include an array controller programmed to operate the plurality of fan units at peak efficiency. The plurality of fan units may be arranged in a true array configuration, a spaced pattern array configuration, a checker board array configuration, rows slightly offset array configuration, columns slightly offset array configuration, or a staggered array configuration.

Abstract: The present invention provides a system which comprises primary supply pumps and secondary supply pumps and controls pressurized water supply systems, air-conditioning systems, or the like that supply chilled water or hot water using these pumps. In the present invention, calculation is carried out based on measurement signals obtained by measuring pressure, flow rate, open rate of valves, etc. by providing sensors in supply channels.

Abstract: The present invention provides a fan installation for a cooling system of a motor vehicle, comprising at least two fans which respectively have an electric fan motor arranged in a separate housing and a fan wheel which can be driven by the fan motor. The fan installation also comprises a control unit for operating the fan motors. The invention provides for an improved fan installation with a simple and cost-effective design, which is achieved by arranging the control unit in the housing of one of the fans for operating both fan motors.

Abstract: A multifan-equipped apparatus in which a plurality of objects mounted are controllably cooled by blowing air using a fan-unit assembly composed of a plurality of fan units. The plural fan units are divided into a plurality of groups; the fan units in the same group are arranged in a queue. And one of the fan units of each group is a master fan unit that is autonomically adjustable in revolutions per minute (rpm) in accordance with a current apparatus-environment temperature and serves to make a tuning control on the rpm of at least one of the remaining fan units in the same group so as to adjust the rpm to a first estimated value corresponding to the autonomic-adjusted rpm of the master fan unit.

Abstract: An invented fluidic (hydraulic/pneumatic) actuation system is described wherein bidirectional, hydraulic/pneumatically driven elements of multiple components in a common hydraulic/pneumatic circuit inherently provide increases in pressure upon reaching mechanical end points limiting, arresting or stopping further mechanical movement or travel of the driven element of any particular component that switches a sequencing valve system and/or electro-hydraulic/pneumatic pressure switches for directing hydraulic/pneumatic power to other hydraulically/pneumatically driven components in the hydraulic/pneumatic circuit in a timed, sequenced and velocity controlled manner.

Abstract: A pumping arrangement, for example for liquid chromatography, comprises a first liquid reservoir at a first height level, connected via a first hydraulic path to a pumping means; a second liquid reservoir at a second height level, connected via a second hydraulic path to the pumping means; and filtration devices arranged in the first and in the second hydraulic path. Each filtration device comprises an outer member (1) forming a first chamber (6), and an inner member (2) arranged within the outer member and forming a second chamber (5). The inner member (2) is porous and acts as a filter for liquid flowing from the first chamber to the second chamber. The arrangement ensures efficient filtering and prevents undesired backflow of liquid.

Abstract: A method for controlling the operation of one or more electrically-operated pumps (11, 12) to pump a liquid from a well or sump (10) which, in use, receives a substantially continuous inflow of said liquid, characterized in that the method includes the step of starting or stopping each pump in relation to the approach of a change of tariff for the electricity supplied for the operation of each said pump (11, 12).

Abstract: A system for variable speed control of a plurality of motors under variable load demand is provided. The system includes a constant power source and a plurality of motors having electrical circuits with switches to connect with the constant power source. The system further includes a variable speed drive for driving each of the plurality of motors at variable speed, wherein each of the plurality of motors includes a switch to connect with the variable speed drive. Each of the plurality of motors is selectively electrically connected with the variable speed drive and the constant power source via the switches, for driving the each of the plurality of motors at one of variable and constant speed in response to load demands. To prevent short cycling of the motors under situations of increasing system demand, the control algorithm for the electrical switches provides hysteresis by overspeeding one of the motors before switching from variable speed mode to constant speed mode.

Abstract: The present invention provides a electric submersible pump assembly for producing a fluid from a production zone to the surface and operated independently by one or more electric submersible motors using a dual or multiple gearbox, the electric submersible pump assembly including an inlet pump having a section head into which fluid enters from the production zone to the inlet pump, an outlet pump having an intake section communicating with the inlet pump so that fluid received therefrom is discharged through the outlet pump, an electric submersible motor, a first motor interface that connects the electric submersible motor to the inlet pump, and a second motor interface that connects the electric submersible motor to the outlet pump; each motor interface having a gearbox that connects to the electric submersible motor, a pump shaft connector that connects to the pump, and a seal section that joins the pump shaft connector to the gearbox.

Abstract: A method and apparatus for dispensing fluids includes first and second fluid pumps coupled with a source of the fluid. Each of the pumps includes a flow switch for sensing output flow from the associated pump. When one of the pumps malfunctions, the associated flow switch produces a fault signal which triggers a controller to activate the second pump to complete the dispensing of a dose of fluid from the source. A timer measures the duration of the flow from each of the pumps so that a full dose of fluid is dispensed from the two pumps in the event that one of the pumps malfunctions.

Abstract: In a pump equipment having one or more rotary pumps for hydraulic circuit, the intake port is communicated with the shaft hole for inserting the drive shaft and fluid flows through the shaft hole to a fluid groove provided in inner surfaces of the pump room for the purpose of lubrication. To prevent fluid leakage to outside, first and second oil seals are disposed for filling the clearance between the drive shaft and the shaft hole and, preferably, a communicating conduit is provided between the first and second oil seals to transmit the fluid leaked through the first oil seal to a low pressure fluid conduit of the hydraulic circuit. In particular, in the pump equipment having plural rotary pumps, the respective discharge ports of the rotary pumps are located at the points which are nearly symmetrical with respect to the center axis of the drive shaft to counterbalance each other, the reaction forces against the drive shaft to be produced by the high pressure at the respective discharge ports.

Abstract: A system for variable speed control of a plurality of compressors under variable load demand. The system includes a constant power source and a plurality of compressor motors having switches to connect with the constant power source. The system further includes a variable speed drive for driving any one of the plurality of compressor motors at variable speed, wherein each of the plurality of compressor motors includes a switch to connect with the variable speed drive. Each of the plurality of compressor motors is selectively electrically connected with the variable speed drive or the constant power source via the switches, for driving the each of the plurality of motors at one of variable or constant speed in response to compressor load demands.

Abstract: The present invention relates to an infusion—suction (I/a) cassette (20) provided with suction system having both a peristaltic or volumetric pump (21) and a pressure sensitive (or Venturi) pump (30), comprising a fluid suction line (27) from the surgical handpiece, a vacuum sensor (22), a valve (29) blocking the passive suction, a collection tank (25), a feeding line (28) for a sterile irrigation solution, a first passage valve (23) for the irrigation solution and a second valve (24) for interruption of the passage of the irrigation solution, a handpiece irrigation line (26), a peristaltic or in any case volumetric line (21), about which the suction line passes, and a pressure sensitive pump (30), connected to the suction line (27) by a vacuum sensor (22), activation of the peristaltic or in any case volumetric pump (21) involving the closure of said passive suction blocking valve (29) and the activation of said pressure sensitive pump (30), the activation of the pressure sensitive pump (30) involving

Abstract: The present invention provides a system which comprises primary supply pumps and secondary supply pumps and controls pressurized water supply systems, air-conditioning systems, or the like that supply chilled water or hot water using these pumps. In the present invention, calculation is carried out based on measurement signals obtained by measuring pressure, flow rate, open rate of valves, etc. by providing sensors in supply channels.

Abstract: A multifan-equipped apparatus in which a plurality of objects mounted are controllably cooled by blowing air using a fan-unit assembly composed of a plurality of fan units. The plural fan units are divided into a plurality of groups; the fan units in the same group are arranged in a queue. And one of the fan units of each group is a master fan unit that is autonomically adjustable in revolutions per minute (rpm) in accordance with a current apparatus-environment temperature and serves to make a tuning control on the rpm of at least one of the remaining fan units in the same group so as to adjust the rpm to a first estimated value corresponding to the autonomic-adjusted rpm of the master fan unit.

Abstract: An operation portion reads an analyzing time and an analyzing flow rate from a storing portion for a next analysis to calculate a liquid delivery quantity per analysis for the next analysis, and transmits the liquid delivery quantity per analysis to a comparison portion. The comparison portion compares a pump capacity and the liquid delivery quantity per analysis, and when the comparison portion determines that the pump capacity is larger than the liquid delivery quantity per analysis, a control portion allows a mobile phase in the next analysis to be delivered by only one cycle discharging operation in a low flow rate mode. Thus, in a micro-liquid chromatography, influence of a pulsating flow can be suppressed.

Abstract: A method for controlling the operation of one or more electrically-operated pumps (11, 12) to pump a liquid from a well or sump (10) which, in use, receives a substantially continuous inflow of said liquid, characterized in that the method includes the step of starting or stopping each pump in relation to the approach of a change of tariff for the electricity supplied for the operation of each said pump (11, 12).

Abstract: A system, such as a computer system, has cooling fans, each having a fan motor and fan blades. The fan motor operates to rotate the fan blades at a variable rotational speed. A frequency generator generates a reference speed signal having a reference frequency and a reference phase. Tachometers measure the variable rotational speeds of the fan blades of corresponding fans and provide corresponding fan speed signals representative of the variable rotational speeds of the corresponding fans. Each fan speed signal has a fan frequency and a fan phase. Motor controllers control the variable rotational speed of corresponding fan blades of corresponding fans based on the reference speed signal and the corresponding fan speed signals.

Abstract: An apparatus and method for providing redundant power and redundant fan speed control to a plurality of fans is provided. A first power supply input is electrically connected to a second power supply input to provide a combined power supply input. First and second fan speed controllers each having an input and an output are provided, along with first and second power converters each having an input and an output. The combined power supply input is electrically connected to the input of the first fan speed controller and the input of the first power converter. The combined power supply input is also electrically connected to the input of the second fan speed controller and the input of the second power converter. The output of the first fan speed controller is electrically combined with the output of the second fan speed controller to provide a combined fan speed control signal. The combined fan speed control signal is electrically connected to the plurality of fans.

Abstract: In a pump equipment having one or more rotary pumps for a hydraulic circuit, the intake port is communicated with the shaft hole for inserting the drive shaft and fluid flows through the shaft hole to a fluid groove provided in inner surfaces of the pump room for the purpose of lubrication. To prevent fluid leakage to the outside, first and second oil seals are disposed for filling the clearance between the drive shaft and the shaft hole and, preferably, a communicating conduit is provided between the first and second oil seals to transmit the fluid leaked through the first oil seal to a low pressure fluid conduit of the hydraulic circuit. In particular, in the pump equipment having plural rotary pumps, the respective discharge ports of the rotary pumps are located at the points which are nearly symmetrical with respect to the center axis of the drive shaft to counterbalance each other, the reaction forces against the drive shaft to be produced by the high pressure at the respective discharge ports.

Abstract: A control device for a diaphragm pump to feed a filter press or similar user unit comprising a three-phase electric driving motor for the pump which is connected to a supply main via a variable-frequency converter, which frequency converter has an analogue output at which a signal will appear which corresponds to the respective motor torque, a standard r.p.m. set-point adjuster to the input of which the actual signal is provided via an inverter and in which a graph is stored which produces an interdependences between the motor torque and the speed such that if the actual-signal rates are small the graph for the speed runs along a constant maximum value and if a preset rate is reached for the actual signal it gradually declines to a minimum value, and an attenuation member for the actual signal.

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: The invention relates to a pump system for providing and maintaining a controlled outflow, comprising a couple of piston pump units (1a, 1b), having at least two cylinders (2a, 2b, 2c, 2d) each with a piston (3a, 3b, 3c, 3d) slidably arranged in each cylinder. It further comprises devices for controllably moving the piston in each cylinder, namely by an eccentric wheel (15a, 15b, 15c, 15d) for each of the pistons, acting on one end thereof. There is also provided a control unit for dynamically changing the speed of movement of the devices for moving the piston, in response to pressure changes in the system on the pressure side, for maintaining a desired flow out of the pump.

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: A sequential controller is provided for sequencing multiple electric loads such electric pumps. That is, for each cycle the next load is designated as the lead load in a round-robin fashion. The controller uses cost effective electro-mechanical relay logic an thus avoids conventional solid state technology. In order to sequence the loads on each successive cycle, the electro-mechanical relay connected to the sensors comprises a double-throw contact set. The double-throw contact set comprises two complementary contacts, both of which alternate between normally open and normally closed on each successive cycle. In this manner one each successive cycle, the pumps designated as the lead pump and the lag pump automatically alternate in a round-robin fashion. Further, when the lead pump is disabled the lag pump is immediately actuated without disruption of service.

Abstract: A high-pressure reciprocating pump is constructed such that a plurality of plungers connected to a driver are made to move back and forth and intake channels or discharge channels are opened and closed by valves in synchronism with movements of the plungers for transferring a fluid under high pressure.

Abstract: A pump unit includes a first plunger pump including a suction port arranged at an end of the first pump distant from a camshaft and a discharge port arranged at another end thereof near the camshaft, and a plunger second pump including a suction port arranged at an end of the second pump near the camshaft and a discharge port arranged at another end thereof distant from the camshaft. The first and second pumps are arranged in parallel with each other along the camshaft so that plungers of the first and second pumps contact corresponding cams of the camshaft. The first and second pumps are connected in series so that the discharge port of the first pump communicates with the suction port of the second pump.

Abstract: The invention is concerned with an electronic control unit (1) for the electric motor of a vacuum pump (100) comprising a suction port (119), an exhaust port (120) and pumping stages formed by rotor disks (113, 114) secured to a rotating shaft driven by an electric motor, and stator rings (115, 116) secured to a pump housing (101) and cooperating with said rotor disks. The unit (1) comprises: a housing (2), first leads (50) for electrically feeding the control unit, second leads (60) for electrically feeding the motor of the pump (100), a circuit for generating a voltage adapted to feed the motor, the circuit generating drive signals (A, B, D, E, G, H, PWM) and providing at least a pulsating signal (PWM the width of which for combining said drive signals can be modulated, and means (201, 202, 203) for combining the, pulsating signal (PWM) with at least one of the drive signals (A, D, G) so as to change the rms voltage of said voltage system.

Abstract: A refrigeration system having a plurality of variable speed compressors, each variable speed compressor operating at a speed substantially the same as the other energized variable speed compressors, the speed being below a maximum speed of the compressors.

Abstract: Balancing the load between compressors is not trivial. An approach is disclosed to balance loads for compression systems which have the characteristic that the surge parameters, S, change in the same direction with rotational speed during the balancing process. Load balancing control involves equalizing the pressure ratio, rotational speed, or power (or functions of these) when the compressors are operating far from surge. Then, as surge is approached, all compressors are controlled, such that they arrive at their surge control lines simultaneously.

Abstract: A positive displacement pump includes a plurality of rotors accommodated in a housing, each of the rotors having a non-circular sectional shape, bearings for supporting rotation of the rotors, a fluid inlet formed in the housing on its suction side and a fluid outlet formed in the housing on its discharge side, motors for independently rotating the plurality of rotors, and detecting devices for detecting a rotating angle and/or a rotation frequency of each of the rotors. While the plurality of rotors are controlled to be synchronously rotated basis on of signals from the detecting devices, a change of a volume of a space defined by the rotors and housing from the suction side to the discharge side is utilized to thereby draw in and discharge a fluid.

Abstract: A superhigh pressure generator system is provided which comprises first, second and reserve boosters 1, 2, 3 which are respectively provided with a plunger chambers 4a, 4b, 4c within single rod-type oil hydraulic cylinders 7a, 7b, 7c on the plunger side and are operative to pressurize water sucked into the respective plunger chambers to superhigh pressure, the boosters being connected in parallel each other to a water discharge line 9 via check valves 6a, 6b, 6c respectively. First, second and reserve 3-position directional control valves 13, 14, 15 are interposed between the oil hydraulic cylinders 7a, 7b, 7c of the respective boosters on one hand and first and second oil hydraulic pumps 11, 12 on the other hand so as to permit a reciprocating motion of the oil hydraulic cylinders. On-off valves 20, 21, 23, 22 are respectively provided on discharge lines 17, 18, 19, 16 which connect the three-position directional control valves 13, 14, 15 to the first and second oil hydraulic pumps 11, 12.

Abstract: A multichannel pump system for HPLC and other uses has a plurality of fluid pumps whose input is fed separately to at least one high pressure mixing unit downstream of the pumps and any associated items such as pulse dampeners and pressure transducers. A pump controller is connected to control each of the pumps separately in a coordinated manner to provide a plurality of operational modes. The operational modes include an isocratic mode, in which optionally the output of solvent of like composition from two or more pumps is pooled to provide increased output capacity, as well as binary, ternary, etc., gradient modes in which different solvents are selectively mixed before being applied to an analytical unit such as an HPLC column. The pump system further includes a novel linear drive pump having interchangeable piston modules providing different ranges of flow rates. The linear drive pump is capable of providing precise solvent delivery at high pressure for flow rates from 20 ml/minute down to 0.

Abstract: A gas compressor with at least three hydraulic cylinders is connected to a source of natural gas by a gas line. The gas line can also be removably attached to a storage tank. A hydraulic system is also connected to the cylinders. The compressor additionally includes pressure controls which allow the pistons in the hydraulic cylinders to complete the compression stroke in a staged manner. The cylinders are thereby sequentially emptied of gas. Gas at a sufficient initial pressure, entering the cylinders at the completion of the compression cycle, drives the return stroke of the pistons. A pressure switch controls the pressure level of the compressed gas, and aborts the compression cycle when a predetermined pressure in the storage tank has been reached.

Abstract: In a plant equipment comprising apparatus of a plurality of systems and control means for switching the systems and changing capacities of the apparatus, an apparatus of each system bas a rated capacity which is 1/N of a capacity of the whole equipment, and the plant equipment is constituted of (N+1) systems. In conditions of normal operation, all the (N+1) systems are operated at capacities less than the rated capacity through the control means. During normal operation, when one system is inspected, or when an abnormality occurs in one system, this system is stopped by the control means. Capacities of apparatus in N of the systems which are operated are increased to the rated 1/N capacity through the control means, and operation is continued with a structure of 1/N capacity.times.N systems. When the maintenance of apparatus in the stopped system is finished, the stopped system is restarted, so as to operate all of the (N+1) systems at capacities less than the rated capacity again.

Abstract: A cooling apparatus for an electronic system, includes a coolant tank, main pumps, heat exchangers, a common supplementary pump, and supplementary check valves. The coolant tank temporarily stores a coolant. The main pumps are respectively arranged in a plurality of heat generators in the electronic system, and the main pumps supply the coolant from the coolant tank to the heat generators. The heat exchangers cool the coolant from each of the heat generators and return the coolant to the coolant tank. The common supplementary pump is operated when any one of the main pumps has failed and supplies the coolant from the coolant tank. Each of the supplementary check valves has an upstream side connected to an outlet port of the supplementary pump and downstream sides connected to outlet ports of the main pumps. Each of the supplementary check valves is opened when a pressure difference between the upstream side and the downstream side of each of the supplementary check valves is larger than a predetermined value.

Abstract: The present invention discloses a system for pumping a fluid into a common pressure outlet. The system contains a plurality of reciprocating pumps. A separate sensor coupled to one cylinder of each pump provides an electrical signal each time the piston in that cylinder is at a predetermined position. A speed control circuit is provided to independently adjust the speed of each pump. Manual speed control for each pump is provided through a separate throttle for each pump. A pump control circuit coupled to each of the throttles, sensors and speed control circuit controls the operation of the system. An operator determines which of the pumps to operate by closing appropriate bypass switches provided at the pump control circuit, turns on the first (master) pump and adjusts its associated throttle to operate the pump at a desired speed. The operator then turns on each of the remaining (slave) pumps.

Abstract: A multichannel pump system for HPLC and other uses has a plurality of fluid pumps whose input is fed separately to at least one high pressure mixing unit downstream of the pumps and any associated items such as pulse dampeners and pressure transducers. A pump controller is connected to control each of the pumps separately in a coordinated manner to provide a plurality of operational modes. The operational modes include an isocratic mode, in which optionally the output of solvent of like composition from two or more pumps is pooled to provide increased output capacity, as well as binary, ternary, etc., gradient modes in which different solvents are selectively mixed before being applied to an analytical unit such as an HPLC column. The pump system further includes a novel linear drive pump having interchangeable piston modules providing different ranges of flow rates. The linear drive pump is capable of providing precise solvent delivery at high pressure for flow rates from 20 ml/minute down to 0.

Abstract: A scroll type compressor having a pair of scroll type compression units which are encased in the same casing so as to make a common use of a lubricating oil reservoir provided in the casing, wherein the compression units have compression elements, drive shafts, driving motors and other components which are of the same constructions and specifications, and wherein each of the compression units are adapted to be driven selectively by commercial electrical power or through a frequency-variable inverter so as to operate at different speeds. Since both compression units can be made up from the same components such as the compression elements, loads in the production, service and administration, are greatly reduced contributing to a reduction in the labor and cost, while eliminating any mounting error.

Abstract: A heat exchanger includes a rotary compressor having two compression pumps and a motor for driving the compressor pumps, a condenser connected to the rotary compressor, a regulator connected to the condenser and with an evaporator connected to the regulator. An electric power is supplied from an inverter circuit to the motor of the rotary compressor. The output frequency of the inverter circuit is controlled by a frequency controlling device according to a heat load of a heat exchange circuit subjected. The rotary compressor is operated according to a parallel operation pattern in which the two compression pumps are actuated or a single operation pattern in which a single compression pump is actuated. Either one of the two operation patterns is selected by a selecting device according to the operational condition of the heat exchanger. The switching between the single operation and the parallel operation is performed by a switching device according to the output signal of the selecting device.

Abstract: A water flow system for collecting and discharging waste water, storm water and the like includes a water pumping station into which water is delivered through an inflow main and from which water is pumped through a water discharge main. The pumping station has a water collection well, a pair of water pumps and a conduit arrangement by which the suction side of each pump is communicated with the well and the pressure side of each pump is communicated with the discharge main. A secondary conduit also communicates the pressure side of one pump with the suction side of the other pump. A control system is operative to actuate one of the pumps for normal pumping conditions and to actuate both pumps during periods of heavy water inflow to the station, the secondary conduit providing serial flow of water through the pumps under such conditions to substantially increase the water outflow rate from the pumping station in comparison to conventional parallel combined operation of the pumps.