A linear compressor includes, a cylinder, a piston configured to reciprocate inside the cylinder, a motor configured to supply driving force to the piston, a detector configured to detect a motor current and a motor voltage that are applied to the motor, and a controller configured to estimate a stroke of the piston based on the motor current and the motor voltage and to determine a phase difference between the stroke and the motor current. The controller is configured to detect operation information of the linear compressor, determine whether to perform a resonance operation based on the operation information, and control operation of the motor to allow the phase difference to be within a preset phase range.

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.

A pump assembly includes a housing having two parts with internal cylindrical chambers having openings for the inlet and outlet of a pumped fluid, and two longitudinally deformable bellows fastened inside the respective parts of the housing. The opposite end of each bellows has a plug. On the end surface of the housing the bellows are connected to is an opening for the inlet of a working fluid into the corresponding internal chamber. A hydraulic system for controlling the pump assembly includes a tank containing a working fluid, a positive displacement pump, two independent hydraulic pipelines, and a system of valves for alternately connecting the bellows' internal chambers containing working fluid to the pipelines. The internal chamber of each bellows is alternatingly connected to the positive displacement pump for supplying working fluid by a first hydraulic pipeline and to the working fluid tank by a second hydraulic pipeline.

A binary pump in which an operation controller causes each of two liquid delivery pumps to execute, while a secondary discharge process is executed, a suction process, a first pre-pressurizing process, and a standby process. The operation controller causes each of the two liquid delivery pumps to execute a second pre-pressurizing process before proceeding from the secondary discharge process to the primary discharge process. Furthermore, the operation controller causes, as long as continuous liquid delivery by each of the two liquid delivery pumps is not interrupted, at least one of the two liquid delivery pumps to execute avoidance operation of interrupting the standby process and proceeding to the second pre-pressurizing process by using the operation state of each of the two liquid delivery pumps, so as to avoid overlap of execution time zones of the primary discharge processes of the two liquid delivery pumps.

A peristaltic pump, and related system method are provided. The peristaltic pump includes a cam shaft, first and second pinch-valve cams, first and second pinch-valve cam followers, a plunger cam, a plunger-cam follower, a tube receiver, and a spring-biased plunger. The first and second pinch-valve cams are coupled to the cam shaft. The first and second pinch-valve cam followers each engage the first and second pinch-valve cams, respectively. The plunger cam is coupled to the cam shaft. The plunger-cam follower engages the plunger cam. The tube receiver is configured to receive a tube. The spring-biased plunger is coupled to the plunger-cam follower such that the expansion of the plunger cam along a radial angle intersecting the plunger-cam follower as the cam shaft rotates pushes the plunger cam follower towards the plunger and thereby disengages the spring-biased plunger from the tube. A spring coupled to the spring-biased plunger biases the spring-biased plunger to apply the crushing force to the tube.

The present invention relates to a method for moving a fluid comprising the steps a. providing a metering head comprising a metering chamber and a displacement element which delimits said metering chamber, b. moving the displacement element in a suction direction from a first position to a second position, wherein a volume of the metering chamber in the second position of the displacement element is greater than a volume of the metering chamber in the first position of the displacement element such that fluid is drawn into the metering chamber via a fluid inlet during a suction stroke, c. moving the displacement element in a pressure direction from the second position to the first position such that fluid is forced out of the metering chamber via a fluid outlet during a pressure stroke. In order to provide a method for moving a fluid or a corresponding metering pump with which a number of the aforementioned disadvantages are prevented without the need for additional components, it is proposed according to the invention that the movement of the displacement element in suction direction during the suction stroke involve at least two changes of direction before the displacement element reaches the second position and/or that the movement of the displacement element in pressure direction during the pressure stroke involve at least two changes of direction before the displacement element reaches the first position.

Systems and methods for controlling a vertical pumping unit are provided. The method includes a self-learning phase and a running phase, wherein the self-learning phase includes obtaining a self-learning result and the running phase includes controlling a motor of the vertical pumping unit to run according to the self-learning result and preset running parameters. The method enables the vertical pumping unit to adjust running parameters of the running phase according to the self-learning results, avoid the accumulation of errors effectively so that changes in stroke length and stroke frequency caused by the motor V-belt, load belt extension and retraction and other elastic links are limited to a minimum range so as to ensure the running accuracy of the vertical pumping unit.

A peristaltic pump and related-method are disclosed that includes a cam shaft having a plunger cam, a plunger-cam follower that engages the plunger cam of the cam shaft, a tube receiver, a spring, a plunger, a position sensor, and a processor. The tube receiver receives a tube. The spring provides a bias. The plunger is biased toward the tube by the spring and the plunger is to the plunger-cam follower, such that 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. The position sensor determines a position of the plunger and the processor estimates fluid flow within the tube utilizing the position of the plunger.

Method, and associated system, computer program and use, of controlling working range of a pump bellows, including maximum limitations such as maximum retracting position and maximum extension position of the bellows, the method comprising the steps of: a) reading at least a first position of a bellows (6′, 6″) in a closed hydraulic loop volume using at least one position sensor (12′, 12″), g) transmitting a first position signal representing the first position to a control system, h) wherein the control system, based on the at least first position signal: c1) determines the position of the bellows (6′, 6″) represented by the at least first position signal, c2) compares the position of the bellows (6′, 6″) with a predetermined bellows position operating range, and c3) if the position is outside the predetermined bellows position operating range, instructs an oil management system valve (16′, 16″) allowing a dual acting pressure boosting liquid partition device (2) to recalibrate the hydraulic fluid volume in the closed hydraulic loop volume to re-establish a hydraulic fluid volume that causes the at least first position to return to a position within the predetermined bellows position operating range.

A rotatable piston assembly for a reciprocating piston type hydraulic machine includes a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston type hydraulic machine.