Devices and methods for operating a diaphragm compressor. Embodiments of the present disclosure comprise an oil piston being driven to pressurize work oil against the diaphragm of the compressor. In embodiments, an injection pump provides a supplemental flow of work oil in the region of pressurized fluid, and such pump may be part of an actively controlled system. In embodiments, a pressure relief valve vents an overpump flow of work oil, and such valve may be variable. Embodiments provide feedback and control mechanisms, including control of the injection pump and the relief valve.

A liquid feeding device includes a discharge channel, a pump part, a feeding pressure sensor, a non-discharge pressure sensor, a pre-compression part, and a pre-compression speed determination part. The pump part has plunger pumps connected in series or parallel. At least one of the plunger pumps is a closed pump in which communication with the discharge channel is disconnected during a non-discharge time. The pre-compression part causes the closed pump that is after the suction process for sucking the liquid into a pump chamber is completed and during the non-discharge time to execute a pre-compression process to perform a discharge operation until a non-discharge pressure is substantially the same as a feeding pressure based on output of the feeding pressure sensor and output of the non-discharge pressure sensor. The pre-compression speed determination part determines a pre-compression speed of the closed pump in the pre-compression process.

The liquid feeding device includes a discharge speed calculation part configured to calculate a discharge speed v of the plunger pump so that a converted value L.sub.ATM under an atmospheric pressure of a flow rate L.sub.PRE of the mobile phase discharged to the discharge channel from the pump part becomes a set flow rate L.sub.SET using a volume V of the mobile phase in the pump chamber of the closing pump immediately before the precompression process is started, a volume ΔV reduced due to the precompression process of the mobile phase in the pump chamber of the closing pump, and a feeding pressure P; and a discharge operation controller configured to control a discharge speed of the plunger pump to a discharge speed v calculated by the discharge speed calculation part.

Device for pumping liquid hydrogen including, arranged in series between an inlet for fluid to be compressed and an outlet for compressed fluid, a first compression member with a piston forming a first compression stage and a second compression member with a piston forming a second compression stage. The first compression member compresses the liquid hydrogen to a supercritical state. The second compression member compresses the supercritical hydrogen from the first compression member to an increased pressure, in particular, between 200 and 1000 bar.

Systems are provided comprising at least one driving cylinder comprising a driving chamber and a driving piston within the driving chamber. The driving piston separates the driving chamber into a driving fluid zone for receiving a driving fluid and a buffer zone for receiving a buffer fluid. The driving piston is movable in the driving chamber by the driving fluid. The systems may also comprise a driven cylinder comprising a driven chamber and a driven piston moveable in the driven chamber. The driven piston is connected to and driven by the driving piston to move within the driven chamber. The driven chamber comprises an input port configured to receive a driven fluid at a first, lower pressure into the driven chamber and an output port configured to expel the driven fluid at a second, higher pressure from the driven chamber when the driven fluid is pressurized by the driven piston. The buffer fluid is different from the driving fluid and the driven fluid, and the buffer fluid in the buffer zone separates the driving fluid from the driven fluid.

A drive device is provided comprising a working pump, the working pump connected to a membrane fluid pump, and the working pump having a working piston able to oscillate axially between two reversal points for contracting and expanding a working chamber, and a control unit for controlling a movement of the working piston between the two reversal points. The controlled movement of the working piston comprises three temporally successive phases, in a first phase the working piston is accelerated to a speed that is greater than a speed at the end of the first phase, in a second phase the working piston is moved such that a specified speed of the working piston, a specified relative pressure in the working chamber, or a specified force of the working piston is substantially kept constant, and in a third phase the working piston is moved at a negative acceleration.

A method of probabilistically estimating a velocity of a plunger of a beam pump may comprise continuously monitoring well acoustics using a plurality of passive acoustic sensors attached to external structures of the beam pump; digitizing outputs of the plurality of passive acoustic sensors and sending the digitized outputs to a computing device for storage and processing; and using the digitized outputs of the plurality of passive acoustic sensors, estimating a probability of the velocity of the plunger using a hidden Markov model (HMM) to represent a probability of a position and the probability of the velocity of the plunger, the HMM comprising a state space model and an observational model.

There is provided a method of transporting fluid produced from a fluid source having a source pressure to a fluid destination having a destination pressure rating. The method has the steps of determining a compressor power requirement based on the destination pressure rating and an estimated rate of flow. A compressor having a power rating that is less than the determined compressor power requirement is provided. An input of the compressor is connected to the fluid source and connecting an output of the compressor to the fluid destination. The compressor is operated in a high volume mode for a first portion of a compression stroke path and in a low volume move for a remainder of the compression stroke path such that the compressor simulates the output from a compressor with higher power rating.

The performance of a solenoid drive liquid pump can be very dependent on the magnitude and stability of an input voltage, with non-ideal input power resulting in loss of efficiency and potential damage to the pump. Pulse width of drive signals provided to the pump, which cause solenoids to alternately energize to move liquid through the pump, may be adjusted in duration in order to compensate for non-ideal input voltage. A drive control module of the pump gathers voltage information, determines an improved pulse width based upon that voltage information, and then provides drive signals based upon the improved pulse width. Operating in this manner, a pump can operate at or near peak efficiency despite both significant variances in input voltage and non-sinusoidal input voltage, and without customized components or adapters.

A controller for operating a rod pumping unit at a pump speed. The controller includes a processor configured to operate a pump piston of the rod pumping unit at a first speed. The processor is further configured to determine a pump fillage level for a pump stroke based on a position signal and a load signal. The processor is further configured to reduce the pump speed to a second speed based on the pump fillage level for the pump stroke.