A peristaltic pump, and related method, are disclosed that includes a cam shaft, a plunger-cam follower, a tube receiver, a spring, a plunger, a door, and a plunger lift lever. The cam shaft includes a plunger cam. The plunger-cam follower engages with the plunger cam of the cam shaft. The spring provides a bias and the plunger is biased toward the tube receiver by the spring. The plunger is coupled to the plunger-cam follower where expansion of the plunger cam along a radial angle intersecting the plunger-cam follower as the cam shaft rotates actuates the plunger away from the tube receiver. The door lever can be actuated between a first position and a second position. The plunger lift lever is coupled to the door lever to actuate the plunger away from the tube receiver when the door lever is actuated to the second position.

Disclosed herein is a linear compressor. The linear compressor includes a piston, a cylinder, a frame, a first bearing gap formed between an inner circumferential surface of the frame and the outer circumferential surface of the cylinder, a second bearing gap formed between an inner circumferential surface of the cylinder and the outer circumferential surface of the piston, a bearing inflow passage and a bearing side passage formed in the cylinder such that fluid flows from the first bearing gap to the second bearing gap.

A high pressure pump including a linear actuator having a servo motor to axially rotate a hollow rotor shaft in alternating directions, the servo motor having a stator positioned co-axially around the hollow rotor shaft with an interior of the rotor shaft being co-axially coupled to a drive member to convert axial rotation into reciprocal displacement, the drive member being constrained against linear movement and supporting a shaft. At least one piston is coupled to the shaft and the piston is arranged within a cylinder to define a pumping chamber, whereby alternating rotation of the rotor shaft causes reciprocal linear displacement of the piston to pressurize fluid in the pumping chamber. A drive mechanism includes a controller coupled to a servomotor and an encoder to measure movement of the hollow rotor or output shaft and send a feedback signal proportional to the movement to the controller.

An apparatus for connecting a resilient member 1 to a magnetic actuator 2 of a linear compressor. The apparatus includes at least one support member 6 cooperating with a resilient element 1, the support member 6 includes a substantially cylindrical part equipped with intermediate perimeter salient portion 61; at least one fastening element 7 cooperating with the support member 8 and the magnetic actuator 2, and enabling interconnection between a magnetic actuator 2 and a resilient member 1 of a detachable and electrically insulated linear compressor, the fastening element 7 being made in electrically insulating and non-magnetic material.

Apparatus are provided for infusion devices and related systems and operating methods. An exemplary system includes a motor, a sensing arrangement coupled to the motor to provide output indicative of a detected characteristic of the motor when the sensing arrangement is enabled, and a module coupled to the sensing arrangement to periodically enable the sensing arrangement while the motor is idle and detect potential unintended motion of the motor based on the output from the sensing arrangement while periodically enabling the sensing arrangement. In some embodiments, the motor includes a rotor configured such that its rotation provides translational displacement of a plunger in a fluid reservoir, and the sensing arrangement includes one or more sensors configured to provide output indicative of a detected magnetic field of the rotor magnet.

A fluid system such as a fuel system includes a fluid supply and a pump coupled between the fluid supply and a plurality of fluid delivery devices. The pump can be a cryogenic pump such as for liquefied natural gas, with valve mechanisms to control hydraulic actuation of a piston used to pump the liquefied natural gas. An electrically conductive coil is coupled with the piston. Related methodology is disclosed.

An apparatus and a method may control a compressor. The apparatus may control a motor (included in a compressor) such that the motor quickly repeats turn-on and turn-off operations in a cooling power supply time period/section, thereby enabling the compressor to compress refrigerant in the cooling power supply time period/section. Thus, cooling power of a refrigerator may change while the compressor operates with maximum efficiency.

A method of operating a pump can include advancing a stepper motor one or more additional steps in a first direction after detecting a first change in a limit sensor state corresponding to a piston reaching an end of its travel in a first direction. After advancing the stepper motor the additional step or steps in the first direction, the stepper motor can be reversed and advanced in a second direction until a second change in the limit sensor state is detected. The stepper motor can then be advanced in the second direction a predetermined number of steps associated with a full travel of the piston.

An artificial lifting system is disclosed. The artificial lifting system comprises an elongated cylinder fixed to a base or ground. The elongated cylinder receives a piston rod axially movable therein. The piston rod engages a downhole rod pump for driving the rod pump reciprocating uphole and downhole to pump downhole fluid to the surface. A control unit controls the axial movement of the piston rod, and automatically adjust the system operation to adapt to drift of the top and bottom stop positions of the piston rod. In an alternative embodiment, the system further comprises a dump valve controlled by the control unit to prevent over-stroke. In another embodiment, the system further comprises a chemical injection unit for injecting treatment fluid to a wellbore under the control of the control unit.

A control method and a control device applied to an electric fracturing apparatus are provided. The electric fracturing apparatus includes a plunger pump and a first motor configured to drive the plunger pump, and the method includes: acquiring a preset displacement of the plunger pump; acquiring a rotation speed of the first motor and a discharge pressure of the plunger pump; determining a real-time displacement of the plunger pump based on the rotation speed of the first motor and the discharge pressure of the plunger pump and adjusting the real-time displacement; and upon the real-time displacement reaching the preset displacement, allowing the first motor to be kept in a stable operation state.