When a pipe pressure of a common discharge pipe during an independent discharge step in which only one reciprocating pump among a plurality of reciprocating pumps discharges a fluid to the common discharge pipe differs from internal pressures in pump chambers of the respective reciprocating pumps at discharge step start point angles, a stroke adjustment mechanism adjusts, on the basis of a pressure difference P therebetween, effective stroke lengths of cross heads connected to plungers of the predetermined reciprocating pumps so that the internal pressures in the pump chambers reach the pipe pressure at the discharge step start point angles.

The invention relates to a coolant compressor comprising an electric drive unit, a cylinder housing (1), a crankshaft (3) which can be driven by the electric drive unit, and a piston (2) that can be driven by the crankshaft (3) and is guided in a working volume of the cylinder housing (1) for cyclically compressing a coolant which can be conveyed via a suction valve into the working volume, said suction valve comprising a suction opening (7) and a valve closure element (8), preferably a valve spring, which closes the suction opening (7) in cycles. The aim of the invention is to ensure a continuous opening movement of the suction valve during the suction cycle. According to the invention, this is achieved by providing an actuation device (14; 15, 23) which is designed to open the valve closure element (8) in cycles.

Controllability of a linear motor or a compressor is improved in a linear motor system that includes: an armature having magnetic poles and winding wires; a mover having a permanent magnet; and a power conversion unit that outputs AC power to the winding wires, in which the mover and the armature are relatively movable, and the mover or the armature is connected to an elastic body. The linear motor system further includes: a position detection unit that detects and outputs the position of the mover with respect to the armature, a position estimation, or a current detection unit that outputs the value of current flowing through the winding wires; and a control unit that controls the output of the power conversion unit on the basis of the output of the position detection unit, the output of the position estimation unit, or the output of the current detection unit.

A linear compressor and methods of operation, for example, to control a setpoint and vary cooling capacity of the linear compressor, are provided herein. An appliance may include a linear compressor having a reciprocating piston movable in a negative axial direction toward a chamber and positive axial direction away from the chamber. The appliance may further include a motor operatively coupled to the reciprocating piston, the motor having a resting setpoint, an inverter configured to supply a variable frequency waveform to the motor, and a controller configured to control the variable frequency waveform. The controller may be configured to direct a positive DC voltage to the motor to shift the resting setpoint to increase a cooling capacity of the linear compressor.

Disclosed is a portable pump including a reciprocating air compressor arrangement with a crank driving a connecting rod and a piston within a cylinder, the connecting rod being connected to the crank and piston, the crank actuating the piston in a reciprocating motion within and relative to the cylinder, an electric motor having a drive shaft mounted to the crank and rotatable about a drive shaft axis, the drive shaft axis being at least substantially coaxially aligned with an axis of rotation of the crank, a control unit communicating with the electric motor to control the pump, a power supply communicating with the control unit to power the control unit and electric motor, a common housing containing the electric motor, reciprocating air compressor arrangement, control unit, and power supply, and an outlet fluidly connected to the reciprocating air compressor arrangement for fluidly engaging with an pumpable object.

A compressor control module (CCM) controls an output of a variable displacement swash plate compressor. The CCM directly calculates, or receives from an external source, a signal indicating a desired or required output from the compressor, receives a current value of the desired or required output, and receives or calculates a current rotation speed and angle, with respect to a rotation axis, of a swash plate, or a current piston stroke length and a reciprocating frequency of the compressor. The CCM determines a difference between the desired or required output from the compressor and the current value and outputs a signal to a valve driving unit which will adjust an angle of a swash plate such that the actual value becomes closer to, or the same as, the desired or required output, taking into account the additional values received or calculated in the receives or calculates step.

Mechanical tubular diaphragm pump features are presented herein. Such a tubular pump can include a resilient tube having a lumen and a pair of upstream and downstream check valves located along the same fluid pathway as the lumen. The tubular pump further includes a motorized reciprocating unit and a depressor configured to be moved by the motorized reciprocating unit to cyclically depress and release the resilient tube. The resilient tube forces fluid within the lumen downstream past the downstream check valve as the resilient tube is depressed by the depressor, and further pulls upstream fluid past the upstream check valve and into the lumen as the resilient tube returns upon release by the depressor. Multiple resilient tubes may be used in the same pump. The tube(s), depressor, and valves may be attached to a housing that is modularly removable from the motorized reciprocating unit.

Controllability of a linear motor or a compressor is improved. There is provided a linear motor system that includes: an armature having magnetic poles and winding wires; a mover having a permanent magnet; and a power conversion unit that outputs AC power to the winding wires, in which the mover and the armature are relatively movable, and the mover or the armature is connected to an elastic body. The linear motor system further includes: a position detection unit that detects and outputs the position of the mover with respect to the armature, a position estimation, or a current detection unit that outputs the value of current flowing through the winding wires; and a control unit that controls the output of the power conversion unit on the basis of the output of the position detection unit, the output of the position estimation unit, or the output of the current detection unit. In the case where a signal having a frequency substantially the same as the frequency of the AC power is applied to the output of the position detection unit, to the output of the position estimation unit, or to the output of the current detection unit, the control unit changes the frequency of the AC power, and in the case where a signal having a frequency substantially larger than the frequency of the AC power is applied, the control unit keeps the frequency of the AC power substantially the same.

A variable displacement reciprocating piston unit includes a sensor probe, a target, a piston having a top dead center position and a bottom dead center position, and a signal processing unit. The sensor probe, the target, and the piston are located in relation to each other so that the target is moved from being absent from the sensor probe to being present at the sensor probe when the piston travels towards the top dead center position, and the target is moved from being present at the sensor probe to being absent from the sensor probe when the piston travels towards the bottom dead center position. The signal processing unit generates a signal indicating a stroke speed and a stroke length of the piston from a signal from the sensor probe indicating a presence and/or an absence of the target as the target moves relative to the sensor probe.

A compressor having a front housing in which a crank chamber is formed. A cylinder block is coupled to an opposite surface facing the front housing and includes reciprocating pistons in a plurality of cylinder bores. A rear housing is coupled to an opposite surface facing the cylinder block, the rear housing includes a suction chamber and a discharge chamber formed therein. A rotating shaft 400 is inserted via centers of the front housing and the cylinder block, the shaft inserted into a swash plate. A diameter maintenance part is configured to constantly maintain a diameter based on an axis direction of the piston 220. A sensor part is configured to sense a speed and a stroke of the piston in accordance with a change in position of a position determination part positioned on one side of the diameter maintenance part.