A piston type pump includes a pump housing having a pump inlet, a pump outlet, and a piston arrangement connected to a drive shaft. The drive shaft is configured to drive the piston arrangement, and the drive shaft includes a first eccentric. The piston arrangement has a first primary stage piston connected to a first sliding block guide slidably seated on the first eccentric. The first sliding block guide has a main axis, a minor axis, and an inner surface. A first sliding bush is arranged between the first eccentric and the first sliding block guide. The outer surface of the first sliding bush corresponds to the inner surface of the first sliding block guide. Translational movement of the first sliding bush relative to the first sliding block guide is allowed along the main axis and restricted along the minor axis.

A method is provided for controlling operation of a fueling system including a fuel pump driven by an engine geartrain and a fuel accumulator supplied fuel by the fuel pump, comprising: determining whether an operating parameter of the engine is less than a threshold value; responding to the operating parameter being less than the threshold value by causing an inlet valve of the fuel pump to operate in a 100 percent fill mode, whereby a pumping chamber in the fuel pump is approximately fully filled for at least one pumping cycle; determining whether a fuel pressure in the fuel accumulator is greater than a desired value while the inlet valve is in the 100 percent fill mode; and responding to the fuel pressure being greater than the desired value by activating an outlet valve of the fuel accumulator to drain fuel in the fuel accumulator to a fuel tank.

A compressor, which includes a cylinder block and a piston assembly arranged inside the cylinder block; the piston assembly comprises a first piston, a second piston arranged inside the first piston, and a movable assembly connected to the first piston, and the movable assembly is configured to drive the first piston and the second piston to reciprocate; the cylinder block is provided with a first compression chamber that defines a space for the first piston to move up and down; the cylinder block is provided with a gas storage chamber for storing the gas after the first compression, and the gas storage chamber is connected to the first compression chamber; and the cylinder block is also provided with a second compression chamber that defines a space for the second piston to move up and down, and the second compression chamber is connected to the gas storage chamber.

A power end assembly includes a crankshaft section, a crosshead section, and a connector section coupled together by one, two, or more sets of stay rods. The power end may include one or more support plates that are coupled to the crankshaft section and/or crosshead section. The crosshead section includes a plurality of individual crosshead frames. The connector section may include a plurality of individual connector plates or may be a unitary connector plate. The power end is configured to be coupled to a fluid end assembly by coupling the fluid end assembly to the connector plates.

A skid for supporting a reciprocating pump assembly, the reciprocating pump assembly including a power end frame assembly having a pair of end plate segments and a plurality of middle plate segments disposed between the end plate segments. The end plate segments each have at least a pair of feet and the middle plate segments each having at least one foot. The skid includes a base and a plurality of pads extending from the base. At least a portion of the plurality of pads correspond to the end plate segment feet and at least another portion of the plurality of pads correspond to the at least one foot of each middle plate segment.

A positioning structure of a motor of an air compressor contains: a base, a cylinder, the motor, and a transmission mechanism. The base includes a first locating orifice and a second locating orifice. The cylinder includes an air storage seat. A small-diameter gear is fitted on the motor via the first locating orifice. A bearing housing of the motor is accommodated in the first locating orifice. The transmission mechanism actuates a piston to move in the cylinder reciprocately. The base includes two symmetrical elongated plates having two hooks respectively and includes two symmetrical arcuate retainers. An outer wall of the motor is retained by the two symmetrical arcuate retainers, and the two hooks are engaged with the magnetic coil.

A crankshaft is provided. The crankshaft has a first shaft, a second shaft and a first crank arm. A first oil passage is formed in the first shaft along an axis direction of the shaft. A second oil passage is formed in the second shaft along an axis direction of the shaft. The first crank arm is configured to be connected between the first shaft and the second shaft. The first crank arm is provided with a third oil passage. The third oil passage is configured to communicate the first oil passage and the second oil passage. The second shaft is eccentrically provided relative to the axis of the first shaft. A compressor having the crankshaft and a refrigeration device having the compressor are also provided.

A hermetic compressor includes: a compression unit; a motor unit; a crankshaft that connects the motor unit and the compression unit; and a bearing member provided with a shaft receiving hole so as to support the crankshaft in a radial direction. An oil supply groove that defines a part of an oil supply passage is formed on an outer circumferential surface of the crankshaft, and the oil supply groove is provided between the outer circumferential surface of the crankshaft and an inner circumferential surface of the bearing member facing the outer circumferential surface of the crankshaft to be located out of pressed regions generated when the crankshaft rotates. As the oil supply groove that supplies oil to a bearing surface between the crankshaft and a main bearing is formed by avoiding the pressed regions, oil may be smoothly supplied to the bearing surface.

An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

A pump comprising a bore pump fluid end having a reciprocating element bore, a discharge valve assembly comprising a discharge valve seat and a discharge valve body, and a suction valve assembly comprising a suction valve seat and a suction valve body; a hollow, cylindrical reciprocating element; a hollow reciprocating element adapter comprising a first end having a fluid inlet opposite a second end having a fluid outlet, wherein the second end of the reciprocating element adapter is connected to and in fluid communication with the fluid intake end of the reciprocating element; a pump power end having a push rod connected to the first end of the reciprocating element adapter; and a movable manifold comprising a reciprocating element end and a fluid intake end, wherein the reciprocating element end of the movable manifold is connected to and in fluid communication with the fluid inlet of the reciprocating element adapter.