Abstract: Embodiments described herein generally relate to apparatuses, cartridges, and pumps for peristaltic pumping of fluids and associated methods, systems, and devices. The pumping of fluids is, in certain cases, an important aspect of a variety of applications, such as bioanalytical applications (e.g., biological sample analysis, sequencing, identification). The inventive features described herein may, in some embodiments, provide an ability to pump fluids in ways that combine certain advantages of robotic fluid handling systems (e.g., automation, programmability, configurability, flexibility) with certain advantages of microfluidics (e.g., small fluid volumes with high fluid resolution, precision, monolithic consumables, limiting of the wetting of components to consumables).

Abstract: Described herein is a method for producing a sealant. The method includes mixing a first material with a second material at a manufacturing site to produce the sealant. The method also includes applying x-ray energy to the sealant at the manufacturing site. The method includes measuring an amount of fluorescence emitted from the sealant in response to applying the x-ray energy. The method also includes calculating a mix ratio of the first and second materials of the sealant based on the amount of fluorescence. The method includes determining whether the mix ratio is within a predetermined mix ratio range.

Abstract: Apparatus and methods for utilizing pressure exchangers as a source of pressure oscillations. An example method includes operating a plurality of pressure exchangers to pressurize a stream of fluid, injecting the pressurized stream of fluid into a wellbore extending into a subterranean formation, and controlling rotational speed and rotational position of a rotor of each of the pressure exchangers to control amplitude and/or frequency of pressure oscillations within the pressurized stream of fluid being injected into the wellbore.

Abstract: Methods and systems for automatically pulsing different aspiration levels to an ocular probe are disclosed. The probe may be a phacoemulsification probe. A first aspiration level, supplied by a first pump, may be applied to the probe simultaneously with ultrasonic energy. A second aspiration level, supplied by a second pump, may be automatically switched from the first aspiration level, and applied to the probe in a pulsed manner.

Abstract: A compressor may include a shell, first and second compression mechanisms, and first and second motor assemblies. The first compression mechanism may include first and second compression members that are rotatable relative to the shell about first and second rotational axes, respectively. The first motor assembly may be disposed within the shell and may include a first rotor attached to the first compression member. The second compression mechanism may include third and fourth compression members that are rotatable relative to the shell about third and fourth rotational axes, respectively. The second motor assembly may be disposed within the shell and may include a second rotor attached to the third compression member.

Abstract: A compressor may include a shell, first and second compression mechanisms, and first and second motor assemblies. The first compression mechanism may include first and second compression members that are rotatable relative to the shell about first and second rotational axes, respectively. The first motor assembly may be disposed within the shell and may include a first rotor attached to the first compression member and surrounding the first and second compression members. The second compression mechanism may include third and fourth compression members that are rotatable relative to the shell about third and fourth rotational axes, respectively. The second motor assembly may be disposed within the shell and may include a second rotor attached to the third compression member and surrounding the third and fourth compression members.

Abstract: An extra-capillary fluid cycling unit for maintaining and cycling fluid volumes in a cell culture chamber includes a housing and a first flexible reservoir extra-capillary fluid reservoir disposed in the housing. The extra-capillary fluid reservoir is in fluid communication with a cell culture chamber. A second flexible reservoir is also located in the housing, the second flexible reservoir being in fluid communication with a pressure source. A sensor plate is movably disposed in the housing between the extra-capillary reservoir and the second reservoir, wherein the second reservoir is pressurized to move the sensor plate in relation to the extra-capillary reservoir to cause fluid cycling and maintain fluid volumes in the cell growth chamber.

Abstract: According to one embodiment of the present invention, a system for pumping fluid is provided. According to this embodiment, a fluid pumping system comprises a fluid inlet pipe and a fluid outlet pipe. A plurality of pump units are disposed between the inlet and outlet pipes such that the pump units each pump fluid out of the inlet pipe and into the outlet pipe. The pump units each include at least one DC motor. A solar panel may be used to power the pump units.

Abstract: A hydraulic pump includes an adjustment device configured to adjust a delivery volume. The adjustment device is configured to be connected via a shuttle valve to a control pressure supply and to a working line. The working line is supplied by the hydraulic pump. The adjustment device is configured to be alternately supplied with control pressure by the control pressure supply and by the hydraulic pump. The hydraulic pump also includes a nozzle. The nozzle is configured to connect the working line to the control pressure supply in a zero stroke operating mode. The nozzle is formed in or on a valve body of the shuttle valve.

Abstract: The device for energy-optimization on operation of several centrifugal pumps controlled in rotational speed, in a hydraulic installation, begins firstly with determining which pumps as pilot pumps are assigned directly to a consumer and which pumps are hydraulically connected in series upstream of the pilot pumps. Thereafter, one or more energy-optimization circuits are formed, which in each case consist of one or more pilot pumps and of one or more pumps connected in series upstream, which deliver into the pilot pumps, wherein the energy-optimization circuits are selected such that the pumps connected in series upstream in each case are assigned to only one energy-optimization circuit, whereupon the energy-optimization circuits are energy-optimized with respect to the pumps.

Abstract: An industrial fluid circulating system having at least one fluid circulation circuit, includes a plurality of pumps connected in parallel to circulate the fluid through each of the fluid circulation circuit, a separate motor driving each pump, a load detector to sense operating loads on the system and each circuit, and a speed control to vary the speed of each motor to thereby vary the pumping capacity of each pump in response to the detected load on the system, each pump of each respective circuit running simultaneously at a substantially similar speed or a predetermined equal reduced speed of the respective circuit or an almost equal reduced speed or a similar reduced speed.

Abstract: A float switch apparatus for controlling the energization of multiple electric circuits in response to the level of a liquid in a vessel, and a pump system incorporating same, are provided. The apparatus has a guide structure adapted to be mounted in a fixed position relative to the vessel. A first micro-switch with a normal and an engaged position is mounted to the guide structure and is adapted to be connected into a first electric circuit to control the energization thereof. A second microswitch with a normal and an engaged position is mounted to the guide structure at a location above the first micro-switch and is adapted to be connected into a second electric circuit to control the energization thereof. A float rod is slideably mounted to the guide structure for reciprocating movement in a generally vertical direction in a zone above a resting position.

Abstract: A fuel forwarding skid for delivering fuel from a storage area to a plurality of turbines includes at least two pumps for delivering fuel to a skid outlet line. A flow control device is connected to the pumps to control an output of the pumps. A recirculation line is in communication with the skid outlet line and is adapted to return a portion of the fuel in the skid outlet line to the storage area. A flow meter is in communication with the recirculation line to measure a rate of flow in the recirculation line, and the flow control device controls the output of at least one of the pumps in accordance with the rate of flow in the recirculation line.

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 by computing the power consumed in various configurations and selecting the configuration requiring minimum power to operate.

Abstract: An approach is provided in which a cooling manager detects a failed fan included in an electronic enclosure. The electronic enclosure includes multiple fans that each cool different component areas in the electronic enclosure. The cooling manager selects an airflow compensator that corresponds to a functioning fan included in the electronic enclosure, which includes a fixed perforated member and a movable perforated member. In turn, the cooling manager adjusts the selected airflow compensator to redirect a portion of airflow generated by the functioning fan to the component area corresponding to the failed fan.

Abstract: An apparatus for generating negative pressure in an installation for filling containers with liquid bulk product includes a vacuum device, and a control-and-regulating unit. The vacuum device has a controllable suction power, and has a plural electrically-powered vacuum pumps. These are configured to operate in parallel. The control-and-regulating unit is configured to control the number of vacuum pumps that are active, thereby controlling the suction power.

Abstract: A drug infusion system includes an infusion pump; an input device; and a processor, the input device and processor configured to allow an operator to make a selection that specifies a combination of a plurality of drugs to be delivered to a patient, the input device and processor further configured to allow the operator to enter the weight of the patient, at least one of the plurality of drugs delivered based on the entered weight of the patient.

Abstract: The invention relates to a method for realizing a vacuum in at least one vacuum chamber. The method comprises providing an arrangement comprising a plurality of vacuum chambers, wherein each vacuum chamber is connected to a shared vacuum system. The shared vacuum system comprises a plurality of turbo molecular pumps, at least one common fore pump, and a piping system comprising one or more pipes for connecting the at least one common fore pump to each of the plurality of turbo molecular pumps. Each turbo molecular pump is separately connected to a corresponding vacuum chamber. The piping system further comprises flow regulators for controlling a flow within the piping system. The method further comprises selecting at least one vacuum chamber for pump-down, and separately pumping down the at least one selected vacuum chamber by means of the shared vacuum system.

Abstract: An approach is provided in which a cooling manager detects a failed fan included in an electronic enclosure. The electronic enclosure includes multiple fans that each cool different component areas in the electronic enclosure. The cooling manager selects an airflow compensator that corresponds to a functioning fan included in the electronic enclosure, which includes a fixed perforated member and a movable perforated member. In turn, the cooling manager adjusts the selected airflow compensator to redirect a portion of airflow generated by the functioning fan to the component area corresponding to the failed fan.

Abstract: An apparatus for controlling vacuum pressure is provided. The apparatus includes a multiple axis controller, such as a dual axis footpedal, and a processing apparatus, such as an instrument host running software, configured to receive multiple axis data from the multiple axis controller. The apparatus also includes a first pump configured to provide nonzero fluid pressure at a first nonzero fluid pressure level based on a first axis state of the multiple axis controller and a second pump configured to provide nonzero fluid pressure at a second nonzero fluid pressure level based on a second axis state of the multiple axis controller. The processing apparatus causes switching between the first pump and the second pump based on the first axis state and the second axis state of the multiple axis controller.

Abstract: Apparatus for conveying waste streams exhausted from first and second chambers is provided. The apparatus comprises first conduit means comprising an inlet for receiving a waste stream exhausted from the first chamber, and an outlet, and a second conduit means comprising an inlet for receiving a waste stream exhausted from a second chamber, and an outlet. The outlets of the first and second conduit means are connected together. The first conduit means comprises means for generating sonic choking of gas being conveyed towards the outlet of the first conduit means in order to inhibit migration of a component of the waste stream exhausted from the second chamber towards the first chamber.

Abstract: A chemical liquid feeding device for feeding chemical liquid used in a semiconductor fabrication process. The device includes three or more pumps arranged in a line. Each pump has different time points of suction stroke and discharge stroke so that the chemical liquid can be fed uniformly without pulsation.

Abstract: A hydraulic system, including fluid flow generated by a primary pump and a secondary pump, utilizes a regulator control assembly to control fluid flow from each of the primary and secondary pumps such that a desired fluid flow and pressure is maintained at the outlet for varying actuator demands. The regulator control assembly controls the transition from using only the primary pump, to using both the primary and secondary pumps to provide a desired fluid flow and pressure through the outlet to the actuator.

Abstract: According to one embodiment of the present invention, a system for pumping fluid is provided. According to this embodiment, a fluid pumping system comprises a fluid inlet pipe and a fluid outlet pipe. A plurality of pump units are disposed between the inlet and outlet pipes such that the pump units each pump fluid out of the inlet pipe and into the outlet pipe. The pump units each include at least one DC motor. A solar panel may be used to power the pump units.

Abstract: A fluid compression system is disclosed. The fluid compression system may include a first compressor disposed in a first fluid conduit, a first valve disposed in the first fluid conduit upstream of the first compressor, a second valve disposed in the first fluid conduit downstream of the first compressor, a second compressor in fluid communication with the first compressor and configured to selectively pump fluid from the first compressor.

Abstract: A self-adjusting fluid pump that includes a piston pump containing at least one piston with a pressure sensor. The fluid pump including at least one fluid-containing pump chamber within the piston pump, adjacent to said piston, wherein advancing the piston causes fluid flow from the pump chamber to a biological destination, and retracting the piston causes fluid to passively till the pump chamber. A microprocessor, senses piston pressure to calculate the rate of fluid input flow into the pump chamber for each pump cycle. If the output flow rate deviates from the input flow rate by a pre-specified value range, the microprocessor adjusts the piston pump to match the output flow rate with the input flow rate by increasing or decreasing stroke rate (piston velocity), stroke volume, or a combination of both.

Abstract: A method and controller for operating pumps wherein each pump is modelled by a QH model indicating a high-efficiency region, a high-H region and a high-Q region and a rotational speed limit. A controller dynamically maintains a current set of operating pumps and controls their rotational speed (n). In steady-state operation, wherein the pumps operate in the high-efficiency region and below the rotational speed limit, all pumps of the current set are controlled together. If the pumps operate in the high-Q region or beyond the speed limit, a new pump is added to the current set, started and brought to a speed that produces flow. A balancing operation (12-3) follows the pump addition operation, wherein the speed of the pumps of the current set are adjusted for equal heads. If the pumps operate in the high-H region, a pump is removed from the current set of pumps.

Abstract: A float switch to control at least two pumps has a guide with two normally-closed micro-switches and a float rod slidably mounted thereto allowing reciprocating vertical movement. The float rod has one or more lower cam surfaces cooperating with the micro-switches to sequentially release them from their engaged positions to their normal positions during upward movement of the float rod. A float is slidably mounted to the float rod between upper and lower float stops. The shape of the lower cam surfaces is such that the weight of the float rod is insufficient to allow the float rod to move downwardly against resistance provided either by the first micro-switch or separately by the second micro-switch and the weight of the float rod combined with at least a portion of the weight of the float is sufficient to overcome either such resistance and to move the float rod downwardly.

Abstract: An apparatus for controlling vacuum pressure is provided. The apparatus includes a multiple axis controller, such as a dual axis footpedal, and a processing apparatus, such as an instrument host running software, configured to receive multiple axis data from the multiple axis controller. The apparatus also includes a first pump configured to provide nonzero fluid pressure at a first nonzero fluid pressure level based on a first axis state of the multiple axis controller and a second pump configured to provide nonzero fluid pressure at a second nonzero fluid pressure level based on a second axis state of the multiple axis controller. The processing apparatus causes switching between the first pump and the second pump based on the first axis state and the second axis state of the multiple axis controller.

Abstract: Irrigation fluid is aspirated from an eye and through an aspiration instrument by operating a vacuum pump, including moving first and second plungers between respective suction strokes and discharge strokes. Vacuum pressure at an input side of the pump is maintained at a desired vacuum pressure setting by controlling speeds and directions of the plungers, and controlling positions of input and output valves communicating with cylinders in which the plungers move. Controlling is based on the pressure setting and measured pressures in the cylinders. Vacuum pressure is maintained while transitioning from the suction stroke of the first plunger to the suction stroke of the second plunger, by synchronizing respective positions of the plungers and the valves, such that initiation of the suction stroke of the second plunger during the transitioning is delayed until a vacuum pressure in the second cylinder is equal to a vacuum pressure in the first cylinder.

Abstract: The invention relates to a method of realizing a vacuum in a vacuum chamber. The vacuum chamber is connected to a pumping system shared by a plurality of vacuum chambers. The method includes separately pumping down each vacuum chamber. The invention further relates to n arrangement of a plurality of vacuum chambers connected to a pumping system. In this arrangement, the pumping system is arranged for pumping down each vacuum chamber separately.

Abstract: The present invention describes an apparatus (1) and a method for use in regulation of the energy potential in a fluid column located within a pipeline (13), the apparatus (1) including two impellers (2), either one including a rotatable shaft (6) which is provided with a plurality of vanes or plate-shaped blades (8), the impellers (2) being disposed in a housing (4) which constitutes a portion of the pipeline (13), the apparatus (1) communicating with a load (19, 21) and/or an energy source, so that the impellers (2) of the apparatus (1) are arranged to influence the movement of the fluid column within the pipeline (13), the apparatus (1) being arranged to receive the fluid column between the shafts (6) of the impellers (2), the centre axis of said shafts (6) being substantially in the same plane as wall portions of the housing (4) upstream and downstream of the vanes, whereby the rate of the fluid column through the apparatus substantially corresponds to the rate of the fluid column immediately upstream and

Abstract: Embodiments of the invention provide a fire-extinguishing system for injecting foamant into a stream of water. The system can include a flow meter determining a flow rate of the stream of water and a foam pump having an inlet coupled to a supply of foamant and an outlet coupled to the stream of water. The system includes a servo motor driving the foam pump. The servo motor includes a sensor used to determine a rotor shaft speed and/or a rotor shaft torque. A controller can control an operating speed of the servo motor using closed-loop control depending on the flow rate and the rotor shaft speed and/or the rotor shaft torque.

Abstract: A fan array is provided having a frame including a plurality of frame members. The frame members are joined to define a plurality of chambers. Each of a plurality of fan units is configured to be positioned in one of the plurality of chambers. Each fan unit has a motor. A plurality of local motor controllers are joined to corresponding motors. The local motor controllers are configured to control an operation of the corresponding fan unit. A master controller is configured to communicate with the local motor controllers. The master controller is configured to provide the local motor controllers with target operating parameters for the corresponding fan units.

Abstract: The present invention relates to an oil pump control apparatus of a hybrid vehicle that controls an oil pump according to a demand of an output torque and oil temperature, and a method thereof. A oil pump control method includes controlling hydraulic line pressure by operating a oil pump at a maximum power if a starting demand for a hybrid vehicle is detected, calculating a viscosity to correspond to an oil temperature in an engine stop mode and controlling a rotation speed of the oil pump at a low power, and calculating a viscosity according to a variation of a line pressure in a driving mode and controlling the rotation speed of the electric oil pump in either a low power, a middle power, and a high power state.

Abstract: A method for controlling a hydraulic flow within a powertrain comprising an electromechanical transmission mechanically-operatively coupled to an engine adapted to selectively transmit power to an output, wherein the transmission utilizes a hydraulic control system serving a number of hydraulic oil consuming functions includes monitoring minimum hydraulic pressure requirements for each of the functions, determining a requested hydraulic pressure based upon the monitoring minimum hydraulic pressure requirements and physical limits of the hydraulic control system including a maximum pressure, determining a desired flow utilizing a hydraulic control system flow model based upon the requested hydraulic pressure, and utilizing the desired flow to control an auxiliary hydraulic pump.

Abstract: A compressor system including a first compressor and a second compressor. The first and second compressors each include a shell, a compression mechanism disposed within the shell, and a drive member adapted to drive the compression mechanism. A discharge tube assembly interconnects the first compressor and the second compressor, and the discharge tube assembly includes an inlet portion adjacent the first compressor that is inclined relative to another inlet portion adjacent the second compressor. The inlet portion that is inclined is adapted to prevent a backflow of oil through the discharge tube assembly.

Abstract: A method of pressure control for transmissions having a hydraulic circuit selectively communicating with first and second pumps via first and second regulators includes commanding communication to the hydraulic circuit to transition from the first to the second pump and the PCS to set the regulators to a high pressure-regulation level. The hydraulic circuit line pressure is raised to an elevated value exceeding a target value. The line pressure is lowered from the elevated to the target value at or after completing the transition to the second pump. The method may include transitioning communication with the hydraulic circuit from the second to the first pump. The PCS maintains the regulators at the high level and line pressure is raised to the elevated value. PCS sets the regulators to a low level, and line pressure returns to the target only at or after completing the transition to the first pump.

Abstract: An eye treatment system is configured for performing an ocular surgical procedure and includes an eye treatment probe, a treatment console including a controller, and an eye treatment cassette for coupling the eye treatment probe with the treatment console. The eye treatment probe is configured to provide at least irrigation fluid to, and aspiration of fluid from, a subject eye. The cassette comprises a cassette body, first and second arcuate ramps, and a holding tank. The cassette has an engagement axis along which elements of the cassette are configured to generally engage with mating elements of the treatment console. The cassette's first arcuate ramp is proximal a first fluidics channel configured to form a first volumetric pump upon engagement with the treatment console. Also the cassette's second arcuate ramp is proximal a second fluidics channel configured to form a second volumetric pump upon engagement with the treatment console.

Abstract: Method for adjusting a compressed air installation using several electrically driven compressors of what is called the “loaded/unloaded” type and/or the turbo compressor type and/or the compressor type with variable rotational speed, wherein these compressors are each connected to a single compressed air network with their outlets, and wherein use is made of a control box which makes it possible to adjust the pressure in the compressed air network around a target pressure to be set. The adjustment takes place by controlling the flow of one or several of the compressors, in particular in order to increase the overall flow supplied by the compressors when the pressure drops too much, and in order to lower the overall supplied flow when the pressure becomes too high.

Abstract: An apparatus for controlling vacuum pressure is provided. The apparatus includes a multiple axis controller, such as a dual axis footpedal, and a processing apparatus, such as an instrument host running software, configured to receive multiple axis data from the multiple axis controller. The apparatus also includes a first pump configured to provide nonzero fluid pressure at a first nonzero fluid pressure level based on a first axis state of the multiple axis controller and a second pump configured to provide nonzero fluid pressure at a second nonzero fluid pressure level based on a second axis state of the multiple axis controller. The processing apparatus causes switching between the first pump and the second pump based on the first axis state and the second axis state of the multiple axis controller.

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 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 programed 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 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 by computing the power consumed in various configurations and selecting the configuration requiring minimum power to operate.

Abstract: A method of operating a delivery apparatus and a delivery apparatus are disclosed for the continuous delivery of a liquid. The method and the apparatus are suitable in particular for use in a water injection system for injecting water into a main flow of a gas turbine. The delivery apparatus includes a plurality of delivery devices connected parallel to one another. In a first method step, the delivery devices of the delivery apparatus are assigned to at least two delivery device groups. The delivery device groups with the respectively assigned delivery devices are then switched to the active state from the rest mode in a rolling manner in time segments in order to deliver the liquid mass flow. In each case at least one delivery device is therefore operated in the rest mode in a rolling sequence per time segment.

Abstract: A system and method for increasing overall efficiency of a waste water system and increasing working efficiency of individual pump stations by implementing an overflow management system. The individual pump station facilitates delaying a discharge of fluid and stores waste water when a down stream pump station has reached a threshold level, thereby delaying or eliminating an overflow situation.

Abstract: A method for optimizing the operation of several compressor units in a natural gas compression station. After a second or further compressor unit is started, the speeds of the running compressor units are set according to a fixed speed ratio in relation to characteristic data established for each compressor unit. The fixed speed ratio is altered by adjusting the rate of flow to the same percentage via the speed of rotation until the preventive pump valves of the gas compressor station are closed, whereupon the operating points of the compressor units are guided, where possible, in the characteristic data thereof, to the maximum efficiency. The optimum set speed values are determined according to continuous operating characteristics of the gas compression station by coordinated variation of the set speeds of the compressors, taking into account fuel consumption of the gas compression station. The stored fixed speed ratio is adjusted according to the optimum set speed values thus determined and stored.

Abstract: A flood control system for use in a structure having a basement floor below ground level is provided. The flood control system comprises a sump, a main pump positioned in the sump, and a secondary pump positioned in the sum. The secondary pump is raised relative to the main pump to a predetermined elevation. The main pump is energized when a height of water within the sump is at a first level. The secondary pump is energized when a height of water within the sump reaches a second, higher level and is de-energized when a height of water within the sump drops to a third level. A cover is releasably mounted to the sump. The cover includes a first section for covering the main pump and a separate second section for covering the secondary pump. At least one of the first and second sections is hingedly mounted to the sump. A controller is operatively connected to the main pump and the secondary pump.

Abstract: Methods and apparatus for pumping and dispensing are provided in which a peristaltic pump (16, 64) pumps liquid from a package (12), and may be integrated in a dispenser (10). The peristaltic pump (64) is adapted for improved accuracy, cleaning, and maintenance. Also provided are improved tubes (18) for peristaltic pumping that are coupled to self-sealing dispensing valves (92, 104, 110, 120).

Abstract: Disclosed herein is a stable solvent delivery device capable of delivering solvent both at high pressure and at constant flow rate. A solvent delivery device comprises a plurality of plungers which reciprocate in the respective pump chambers including an eluent charge side pump chamber and an eluent discharge side pump chamber, a motor to reciprocate these plungers, a control unit to control the operation of the motor, valves which are respectively set at the eluent inlet and outlet of the eluent charge side pump chamber, a first sensor to measure the quantity of load received by the plunger in the eluent charge side pump chamber, and a second sensor to measure the pressure of the eluent discharged from the eluent discharge side pump chamber.