2579 results about "Plunger pump" patented technology

Valve guide and spring retainer assemblies are described for use in plunger pump housings that incorporate structural features for stress-relief. These pump housing structural features accommodate correspondingly-shaped valve guides and/or spring retainers that are internally fixed in place using one or more non-threaded spacers. Plunger pumps so constructed are relatively resistant to fatigue failure because of stress reductions, and they may incorporate a variety of valve styles, including top and lower stem-guided valves and crow-foot-guided valves, in easily-maintained configurations. Besides securing valve guides and/or spring retainers, non-threaded spacers may be shaped and dimensioned to aid in further reducing stress and to improve volumetric efficiency of the pumps in which they are used.

The invention relates to a hydraulic bidirectional pumping device which comprises a prime motor, a hydraulic oil pump, a hydraulic oil tank, a control valve, a double-action hydraulic cylinder and plunger pumps. The prime motor drives the hydraulic oil pump. The hydraulic bidirectional pumping device utilizes the double-action hydraulic cylinder to drive the plunger pumps on both sides; the cylinder number is increased; stroke times are reduced; the service lives of easily damaged parts are prolonged; the coverage range of flow is effectively enlarged; suction efficiency of fracturing fluid is effectively improved; complexity of the integral structure is reduced; cost of manufacturing, maintenance and the like is reduced; the requirements on a lubricating system are lowered; the double-action hydraulic cylinder reciprocates to do work, so that working efficiency is improved.

The invention relates to a fracturing transmission and high-pressure discharging system. The fracturing transmission and high-pressure discharging system comprises a chassis and is characterized in that a high-power engine, a transfer case, a plurality of variable displacement plunger pumps and a double-acting fracturing pump are arranged on the chassis, the output end of the high-power engine is connected with the input end of the transfer case, the output end of the transfer case comprises a plurality of power take-off ports, and each power take-off port is connected with one variable displacement plunger pump; the variable displacement plunger pumps drive the double-acting fracturing pump through a hydraulic system. The fracturing transmission and high-pressure discharging system further comprises a system radiator and a heat dissipation plunger pump used for driving the system radiator, and the heat dissipation plunger pump is connected with one power take-off port of the transfer case. The power take-off ports of the transfer case and the variable displacement plunger pumps are arranged annularly. The fracturing transmission and high-pressure discharging system has the advantages that hydraulic driving replaces mechanical transmission, and working vibration is reduced; the layout space of a whole vehicle is saved, and meanwhile, operating efficiency and the stability of the whole vehicle are improved.

The invention discloses a five-cylinder plunger pump with an integral power end structure. According to the five-cylinder plunger pump, an integral welding structure is adopted for a crankshaft box body and a crosshead box body in a five-cylinder plunger pump power end assembly, so that the structural strength of the power end assembly is higher, the supporting stability is better, and the whole pump vibration can be reduced; the cylinder spacing is 13-14 inches, the bearing area of connecting rods, crossheads and bearing bushes is increased, a guarantee is provided for the output of the high-power of the five-cylinder plunger pump, the high-power five-cylinder plunger pump can effectively solve the problem that the shale gas fracturing well site area is narrow and the required fracturingequipment is relatively large, the use of equipment can be reduced, and the wellsite arrangement is facilitated; the 11-inches long-stroke design can better realize large-displacement operation requirements and improve the operation efficiency; and according to the multi-point supporting design of crankcase bodies, crosshead box bodies and the hydraulic end assembly, the supporting strength of thefive-cylinder plunger pump can be improved, the vibration is reduced, the high-load operation is better guaranteed, and the operation is more stable.

The invention relates to a plunger pump used for pumping ultralow-temperature liquid nitrogen, which comprises a power end and a cold end, wherein the cold end comprises a cold end shell; one end of the cold end shell is provided with a plunger; the other end of the cold end shell is provided with a suction inlet and an exhaust port; the positions of the suction inlet and an exhaust port of the cold end shell are provided with a valve seat; one end of the plunger is connected with a power end; the other end of the plunger is mutually matched with the cold end shell and the valve seat to form an inner cavity; the valve seat is provided with a first channel and a second channel, wherein the first channel is used for communicating the inner cavity with the suction inlet; the second channel is used for communicating the inner cavity with the exhaust port; a lower-pressure valve used for controlling the liquid nitrogen to be sucked into the inner cavity is arranged between the first channel and the inner cavity; a high-pressure valve used for controlling the liquid nitrogen to be discharged out of the inner cavity is arranged in the second channel; the plunger is driven by the power end to carry out linear reciprocating motion in the inner cavity so as to drive the lower-pressure valve or the high-pressure valve to be opened and closed; when the low-pressure valve is opened, the liquid nitrogen enters the inner cavity from the suction inlet; when the high-pressure valve is opened, the liquid nitrogen is discharged out of the inner cavity from the exhaust port; and the cold end shell is provided with an overflow port communicated with the inner cavity.

The invention belongs to the technical field of low-temperature high-pressure plunger pumps, and particularly relates to a cold end of a low-temperature high-pressure plunger pump. The cold end comprises a cold end shell body, a plunger and a cylinder sleeve, wherein the plunger is arranged inside the cylinder sleeve, the cylinder sleeve is located inside the cold end shell body, a connecting locking device is arranged at the front end of the cold end shell body, the cold end shell body comprises a left cavity and a right cavity which communicate with each other, the right cavity internally comprises the cylinder sleeve, a valve set and a discharging flange, and the valve set comprises a valve seat, a high-pressure valve arranged in the valve seat and a low-pressure valve arranged betweenthe cylinder sleeve and the valve seat. According to the cold end of the low-temperature high-pressure plunger pump, the novel valve set structure adopts metal sealing, continuous opening and closingof the high-pressure valve and the low-pressure valve are achieved, and normal-pressure ultralow-temperature liquid nitrogen is converted into high-pressure low-temperature liquid nitrogen and is discharged so that the requirement for high-frequency opening and closing can be met, the characteristics of being low in conveying medium temperature and high in output pressure are achieved, and the problem that a common plunger pump cannot pump the low-temperature and high-pressure liquid nitrogen is solved.

The invention discloses a device and method for preparing nitrogen foam cement. The preparing device comprises a foam cement producer, a liquid nitrogen evaporator, a liquid nitrogen plunger pump, a foam liquid plunger pump, a foam liquid tank, a heat exchange system, a liquid nitrogen pipeline, a high-pressure cement paste pipeline, a first pipeline, a foam cement discharge pipeline and a densitydetecting device. The heat generated by a power unit, a hydraulic system and other devices in a nitrogen foam well fixing device is recovered through the heat exchange system, the recovered heat is used as a heat source of the liquid nitrogen evaporator, energy conservation and environment protection are realized, the energy utilization rate is high, and equipment input is low. Liquid nitrogen and foam liquid are pressurized through a high-pressure liquid nitrogen plunger pump and a high-pressure foam liquid plunger pump, the mixing uniformity is increased, and the density of foam cement is reduced. The density of the foam cement is detected in real time through the density detecting device, the flow of the liquid nitrogen and/or foam liquid is adjusted according to the density, and the density is simply controlled. By arranging a clear water tank, after operation ends, the equipment and pipelines are flushed, and the service life is polonged.

The invention belongs to the field of oil equipment, and particularly relates to full-automatic intelligent remote-control cementing equipment. A long-distance automatic displacement and density automatic control system being used for the cementing equipment is characterized in that the long-distance automatic displacement and density automatic control system at least comprises a power unit and acontrol unit. The power unit comprises an engine, a gearbox and a plunger pump, and the control unit comprises a device operation screen, a device PLC processor, a remote-control operation screen, a remote-control PLC processor and an Anybus module. Operating personnel write in a set displacement set value or a set density value on the remote-control operation screen or the device operation screen, after the device PLC processor reads the set displacement information, a set gear needed by the current set displacement and the accelerator position are calculated through program internal calculation, so that the rotating speed of the engine and the gears of the gearbox are controlled, finally the long-distance automatic displacement and density automatic control system is used for controllingthe input rotating speed of the plunger pump, and the purpose of controlling the discharging displacement of the plunger pump is achieved.

A modular fluid end for a multiplex plunger pump, each module machined from a single-piece steel forging with a plunger bore intersected by a linear suction/discharge bore and pumped fluid is discharged straight out through a top of the module into a discharge manifold made up using 1502 frac iron components. A compression clamp applies a crush load to opposed sides of the modules to extend service life.

The invention discloses a hydraulic fracturing system for driving a plunger pump by using a turbine engine. The fracturing system comprises a fracturing device, a high-low pressure pipe joint, a mixing device, a sand blender and the like, a power source of the fracturing device is the turbine engine, fuel of the turbine engine is natural gas or diesel, the plunger pump is driven by the turbine engine, the problems of existing diesel driving and electromotor driving are solved, fuel supply of the turbine engine adopting a dual-fuel system is diverse and is not limited, especially, the cost is more saved when the natural gas serves as the fuel. The gas source supply modes of the natural gas are diverse in the whole hydraulic fracturing system, requirements for more clients can be better met,the whole fracturing device is arranged on a straight line in the direction of power transmission, the whole gravity center of the fracturing device is better lowered, and the stability and safety ofthe operation and transferring states of the fracturing device are improved.

The invention discloses cementing equipment with mutually standby hydraulic systems. The cementing equipment comprises a loading system, a hydraulic system connected with the loading system and a power system for driving the hydraulic system. The hydraulic system at least comprises a hydraulic pump, a switching device and an overflow valve, the hydraulic system is connected with a mixing system, and the hydraulic system is connected with a slurry mixing system provided with an AMS automatic slurry mixing system, a centrifugal pump circulating and filling system; the slurry mixing system is controlled and adjusted through a control system, the control system is arranged on a computer control platform, and the control platform is arranged on the loading system; and the loading system is based on one or more of a vehicle-mounted chassis or a trailer chassis or a skid-mounted chassis, wherein a semi-trailer based on the trailer chassis can be fixedly connected with a plurality of engines, a plurality of gear boxes, a plurality of plunger pumps, at least one metering tank, the slurry mixing system, a high-low pressure manifold, the control system, the hydraulic system and an electrical system.

The invention discloses continuous large-power turbine fracturing equipment. The large-power turbine fracturing equipment comprises a turbine engine, a reduction box, a transmission shaft and a plunger pump, wherein the turbine engine and the reduction box are arranged on the same straight line; the reduction box is connected to the plunger pump through a transmission shaft; and an angle of the transmission shaft ranges from 2 degrees to 4 degrees. The continuous large-power turbine fracturing equipment has the beneficial effects that: a chassis T1 material is selected, so that a stable working platform is provided for the equipment; the turbine engine and the reduction box are on the same straight line, the transmission shaft is arranged between the reduction box and the plunger pump, andthe angle of the transmission shaft ranges from 2 degrees to 4 degrees, so that stable and efficient transmission of the turbine engine is guaranteed, and a fault occurrence rate is reduced; a lubricating system driven by an auxiliary power system guarantees that the turbine engine, the reduction box and the plunger pump work under a proper environment; dual lubricating systems guarantee that theplunger pump realizes continuous operation under power of 5000 HP or higher; and the technical means finally can meet continuous large-power operation requirements of the fracturing equipment.

The present invention relates to the technical field of petroleum equipment, in particular to novel ultra-high-power cementing equipment integrated with remote control. The novel ultra-high-power cementing equipment integrated with remote control comprises a loading system and a secondary beam, wherein the secondary beam is connected with a hydraulic system, a power transmission system, a meteringtank, an electrical system, a gas circuit system, a control system and a mixing system from front to rear in sequence, the lower portion of the gas circuit system is provided with a plunger pump, theplunger pump is connected with a high-pressure discharge system; a control platform is arranged at the lower part of the electrical system; the control system is positioned above the control platform; and the control system is connected with the remote control system. The novel ultra-high-power cementing equipment integrated with remote control meets the requirements of high pressure, large displacement, long time and continuous uninterrupted operation during the ultra-deep cementing operation and the ultra-high pressure gas well operation; and the occupied area is small, the pipeline connection is simple, and the maintenance frequency is low.

The invention discloses a manifold system capable of realizing low-pressure suction and high-pressure discharge. The manifold system capable of realizing low-pressure suction and high-pressure discharge comprises a low-pressure manifold, a high-pressure manifold and a plunger pump, wherein the low-pressure manifold inputs a medium to a fluid end of the plunger pump; discharge ports are formed in the fluid end of the plunger pump; and two discharge ports are formed, and connected into the high-pressure manifold. The manifold system capable of realizing low-pressure suction and high-pressure discharge has the following beneficial effects: the five-cylinder plunger pump with a power of 5000 and above guarantees a high-pressure and large-displacement power source of fracturing equipment. A double-discharge form of the five-cylinder plunger pump realizes smooth liquid discharge of the five-cylinder plunger pump, avoids sand accumulation in the low-pressure manifold, and guarantees a large displacement of the fracturing equipment. A large-drift-diameter manifold with a size of 10 inches is adopted as the low-pressure manifold; and double-suction of a U-shaped pipe realizes enough fluid supply for the large displacement of the five-cylinder plunger pump.

The invention discloses turbine fracturing equipment. The turbine fracturing equipment comprises a transporting device, a turbine engine, a reduction gearbox, a transmission mechanism and a fracturingpump, wherein the output end of the turbine engine is connected with one end of the reduction gearbox; the other end of the reduction gearbox is in transmission connection with the fracturing pump; the transportation device is used for bearing the turbine engine, the reduction gearbox, the transmission mechanism and the fracturing pump and comprises a chassis; the chassis is provided with a transporting section, a bearing section and a lapping section which are connected in sequence; when the turbine fracturing equipment is in a working state, the bearing section can be contacted with the ground; and when the turbine fracturing equipment is in a transporting state, the bearing section does not make contact with the ground. The turbine fracturing equipment has the beneficial effects that the equipment adopts the design of linear connection and a special chassis, so that the gravity center of the turbine fracturing equipment is doubly reduced, and the stability and the safety are well ensured; the structure is simpler, and the investment cost and the operation cost are reduced; the collapse risk of the whole fracturing site is reduced; and the turbine fracturing equipment is good intransmission property and is suitable for long-time and bulky load continuous operation conditions.

The invention discloses a plunger pump fluid end. The plunger pump fluid end comprises a valve box, a plunger, a packing sealing assembly, a valve assembly, a valve spring seat, a discharge gland, a discharge pressing cap, a suction gland and a suction pressing cap, wherein the plunger, the packing sealing assembly, the valve assembly, the valve spring seat, the discharge gland, the suction glandand the suction pressing cap are arranged in the valve box; the valve spring seat comprises a bulge, a connecting piece and fins, the connecting piece is connected with the bulge and the fins respectively, and two fins are oppositely arranged; and a containing cavity is formed in the valve box and used for containing the fins. The plunger pump fluid end has beneficial effects that the mounting anddismounting are easier and faster by changing a structure of the valve spring seat and the mounting and fixing mode of the valve spring seat and the valve box, and meanwhile, the service life of thefluid end is prolonged. A plunger and the end surface of the suction gland are changed into cambered surfaces, so that internal fluid can flow conveniently. The valve spring seat can be prevented fromrotating left and right to fall off by additionally arranging the limiting bulge. A first sealing ring and a second sealing ring are both arranged on the valve box, so that abrasion is transferred toa quick-wear part, and the service life of the valve box is prolonged.

The invention discloses a multi-point-support five-cylinder plunger pump. The multi-point-support five-cylinder plunger pump comprises a power end assembly, a hydraulic end assembly and a speed reduction box assembly, wherein the power end assembly comprises a crankshaft box body, a crosshead box body and a space rack, and the crankshaft box body, the crosshead box body and the space rack are connected in sequence; the hydraulic end assembly is fixed on the space rack, the speed reduction box assembly is fixed to the crankshaft box body, the bottom of the crankshaft box body is provided with acrankshaft supporting body, and the crankshaft supporting body is used for supporting the crankshaft supporting box body; the bottom of the crosshead box body is provided with a crosshead supportingbody, the crosshead supporting body is used for supporting the crosshead box body, the bottom of the space rack is provided with a hydraulic supporting body, and the hydraulic supporting body is usedfor supporting the hydraulic end assembly. The multi-point-support five-cylinder plunger pump has the advantages that through the multi-point-support design on the crankshaft box body, the crosshead box body and the hydraulic end assembly, the support strength of the plunger pump can be improved, vibration is reduced, high-load work is better guaranteed, and the plunger pump runs more stably.

The invention discloses a plunger pump driven by a linear motor. The plunger pump is driven by the linear motor, and a motion rule of an assembly is controlled by controlling a motion rule of the linear motor, so that the disadvantages of an existing plunger pump are overcome, and the advantage of the plunger pump is exerted to the maximum extent.

The invention discloses a high-power five-cylinder plunger pump. The stroke of the high-power five-cylinder plunger pump is 10 in, the cylinder spacing is 11.5 in, and the braking power is 5000 HP. The plunger pump has the beneficial effects that the power is large, and the displacement is large; the pump is suitable for electric drive fracturing and turbine fracturing; the integral power end assembly or the split type power end assembly can be selected according to specific operation working conditions, so that the arrangement mode of a fracturing unit or a fracturing vehicle is better realized; and the stable operation with the long stroke and the braking power of 5000 HP is guaranteed by means of the size of the cylinder spacing.

The invention provides a welding robot device for welding of a plunger pump power end shell. The welding robot device for welding of the plunger pump power end shell comprises a controlling system, a portal frame X-Y-Z coordinate system, a welding system, a space positioner and a tool clamp. The tool clamp is used for clamping the plunger pump power end shell, and a plunger pump shell can be one-time clamped; all welding joints of the plunger pump shell can be positionally changed to a flat welding position or a flat fillet welding position through the space positioner; a welding mechanical arm is connected with a coordinate Z-axis in the portal frame X-Y-Z coordinate system, and welding of welding joints in the different positions can be finished; and synchronized driving of the welding mechanical arm, a coordinate X-axis, a coordinate Y-axis, the coordinate Z-axis and the space positioner can be realized, so that continuity during the welding process is guaranteed, and welding quality and welding efficiency are ensured.

The invention provides a reciprocating type three-cylinder plunger pump for an oil and gas field. The reciprocating type three-cylinder plunger pump comprises a gear box assembly, a power end assemblyand a hydraulic end assembly which are transmitted in sequence; and the hydraulic end assembly comprises a disc root and a plunger, the power end assembly comprises a crankshaft, a connecting rod, asliding rail and a crosshead, power is transmitted from the crosshead to the plunger, a pull rod and a fender are arranged between the plunger and the crosshead, the pull rod is fixed on the cross head, the plunger is fixed to the pull rod, the fender is located between the pull rod and the plunger and fixed with the plunger, and the outer diameter of the fender is larger than that of the plungerand the pull rod. The reciprocating type three-cylinder plunger pump can solve the problems that a working medium in a hydraulic end assembly in the prior art is poured into a power end assembly alongthe plunger, a packing is inconvenient to replace, and a connecting rod large-head bearing bush is insufficient in lubrication and the like.

The invention belongs to the technical field of compressed natural gas filling, and particularly relates to an integrated hydraulic station which realizes high integration of an oil tank, plunger pumps, motors, a valve block, a cooler, an instrument and a sensor. The reversing function of hydraulic oil is provided through cooperation of an electro-hydraulic reversing valve and a proximity switch on a hydraulic cylinder, the functions of circulating heating of the low-temperature hydraulic oil, discharging of the high-pressure hydraulic oil and avoiding the hydraulic oil channeling back betweenthe double pumps are realized through cooperation of an unloading valve, a one-way valve and the electro-hydraulic reversing valve in the valve block, the high-pressure difference automatic stop function and the high-pressure gas discharging function are provided, combustible gas leakage and expansion deformation of the oil tank which cannot be recovered caused by high-pressure gas channeling back are avoided, the functions of low oil level monitoring alarm, temperature monitoring alarm and low oil temperature automatic circulating heating before starting of the hydraulic oil tank are provided, a three-way ball valve is adopted to replace an oil return valve block in the aspect of cooling oil return of the hydraulic oil, thus the oil return control function is realize, and the cost and space of the hydraulic station are also reduced.

Provided is an apparatus and a process for preparing graphene by the technology of cavitating jet. The apparatus comprises a storage tank, a water inlet pipe, a valve, a motor, a plunger pump, a compression gauge, a high pressure pipe, a cavitation generator, a cycle water cooling means and a return line. The outlet of the storage tank is connected with the inlet side of the water inlet pipe, andthe outlet side of the water inlet pipe is connected with the water inlet of the plunger pump; the valve is installed on the water inlet pipe, the plunger pump is driven by the motor, and the operating pressure of the plunger pump is displayed on the compression gauge; the water outlet of the plunger pump is connected with the water inlet of the high pressure pipe, and the water outlet of the high pressure pipe is connected with the water inlet of the cavitation generator; the water outlet of the cavitation generator is connected with the water inlet of the return line, the water outlet of the return line is connected with the inlet of the storage tank, and the cycle water cooling means is installed on the return line. The preparation method comprises seven steps. The conception of the invention is scientific; the process is advanced; production cost is low; no environmental pollution is generated; industrial large scale production can be realized; the apparatus and process provided in the invention have a wide application prospect in the technical field of preparing graphene.

The invention discloses a three-dimensional (3D) metal printer. A printing head integrating a ceramic melting furnace and a liquid metal ejector is a key technology for the 3D metal printer. The printing head is made of high temperature resistant ceramic or graphite material, a water cooling eddy current coil is installed on an outer layer, the melting furnace is filled with inert gas to protect liquid metal, and the ejector is a reciprocating type plunger pump. The water cooling eddy current coil is electrified with high-frequency current, and heating power can be adjusted through a high-frequency controller according to factors such as material types, model requirements and processing speeds. The inert gas keeps a certain pressure while protecting the molten metal, flow of the liquid metal is facilitated, and metal residue in the plunger pump and the melting furnace is removed by means of gas simultaneously during shutdown. Besides application to the 3D metal printer, the printing head can also be used for devices for die-cast molding and injection molding of metal material and the like.

The invention relates to an experimental device and an experimental method for multi-source information fusion for fault diagnosis of a hydraulic device. The device comprises the following elements: a variable plunger pump, a gear pump, two motors, two suction filters, five throttle and stop valves, two electromagnetic relief valves, an electromagnetic proportional relief valve, two pressure meters, an energy accumulator, two sets of combined sensors, a three-position four-way electromagnet directional valve, a hydraulic motor and a cooler. The experimental device can simulate eight typical running states (faults) of the hydraulic device, including low efficiency, oil and liquid pollution, air suction, leakage, oil pump fault, relief valve failure, motor failure and mechanical failure and can perform cluster analysis and fusion diagnosis to characteristics of the eight faults through a self organizing maps neural network.

A dual well pumping unit (12) has two hydraulic ram units (26), one for each well (preferably with each ram unit (26) having three hydraulic rams). Each hydraulic ram units is connected to first ram pump (18) and a second ram pump (20). The drive shaft (40) of the first ram pump (18) is coupled to the drive shaft (38) of the second ram pump (20) and to a rotor of a drive motor (16). The ram pump (18) and the ram pump (20) are preferably variable displacement piston pumps which are controlled by a microprocessor based controller (44), such that during the downstroke of the hydraulic ram (26) the ram pump (18) operates as an hydraulic motor powering the ram pump (20) and during the up stroke of the hydraulic ram (26) the ram pump (20) operates as a hydraulic motor to provide assist to the ram pump (18).

A performance testing device for a piston shoe in an axial plunger pump belongs to the technical field of hydraulic elements, and solves the problems that in the prior art a simulator is adopted to carry out the simulation test on the performance parameter of the piston shoe in the plunger pump, the test result has errors, and a piston shoe pair is difficult to be isolated from other friction component pairs when the performance parameter test is carried out in the piston shoe in a practical pump. The performance testing device for the piston shoe in the axial plunger pump comprises a piston shoe, and further comprises a variable frequency motor, a rotating speed and torque sensor, a variable device, a hydraulic cylinder body, a plunger, a flowmeter, a pressure gauge, an oil box and a temperature sensor, wherein the coupling plate of the variable device is fixedly connected with a bottom plate of a support tile of a swash plate through a bolt, the swash plate is supported by the support tile of the swash plate, three screwed holes on each fastening splint are connected with three corresponding screwed holes on one side of the swash plate through the bolts, a waist-shaped slot on each fastening splint corresponds to and is connected with the screwed hole on the side wall of the support tile of the swash plate through bolts, so the swash plate can swing in the support tile of the swash plate. The performance testing device for the piston shoe in the axial plunger pump is used for testing the performance of the piston shoe in the axial plunger pump.

The invention discloses a single-piston type hydraulic free piston engine; in the invention, a traditional reciprocating piston internal combustion engine and a plunger-typed hydraulic pump are integrated into a whole, a pump piston and two compression pistons are simultaneously and directly connected with a power piston in a rigid manner to form a piston component, therefore, a crank link mechanism which can transform the reciprocating movement of the pistons into rotary motion in the internal combustion engine, and a swash plate mechanism which can transform the rotary motion of the pistons into reciprocating movement in a plunger pump can be omitted, and the piston of the internal combustion engine is directly connected with the plunger of the hydraulic pump in a rigid manner. By adopting the technical proposal of the invention, a driving chain can be shortened, the repeated transformation between different movement forms can be omitted, the energy transfer form between an engine and a drive system can be optimized, and the soft readjustment of a power drive unit can be realized.

A pump controller causes a first plunger pump and a second plunger pump connected in series or in parallel to perform intake and compression actions alternately at substantially constant cycles, sets a pressurizing chamber of one of the plunger pumps to a state of a higher pressure than the pressurizing chamber of the other plunger pump, and performs flow rate control by adjusting lift amounts of the first plunger and the second plunger. Thus, it is possible to provide a pump for liquid chromatograph, and a liquid chromatograph, which are capable of reducing pulsations even when an ejection flow rate is changed.

The fully water lubricating and end flow distributing water hydraulic axial plunger pump or motor operates with filtered natural water as work medium and consists of mainly one casing and one rotating cylinder inside the casing. The cylinder has odd holes distributed homogeneously in the same circumference and parallel to the driving or output shaft, plungers of the plunger-sliding shoe assembly are set inside the holes, and the flow distributing sleeve has one end installed in the other end of the holes and the other end set in the holes of the push stopping disc. The push stopping disc floats to the cylinder to compensate the error of parts in machining and installation. The central spring has one end pressing the push stopping disc to the flow distributing disc via plastic rod and the other end pressing the sliding shoe to the inclined disc via the cylinder, ball pivot and backstroke disc, and the driving or output shaft is combined firmly to the cylinder.