Showing papers on "Hydraulic machinery published in 1981"

Method of and system for controlling hydraulic power system

Abstract: A method of and system for controlling a hydraulic power system comprising an internal combustion engine receiving a supply of fuel from a fuel injection pump, and at least one variable displacement hydraulic pump driven by the internal combustion engine. An engine speed deviation is obtained from the difference between a target speed set by an accelerator operation of the internal combustion engine and an output speed thereof. Then a fuel injection target value in predetermined functional relation to the engine speed deviation, is obtained based on at least the engine speed deviation, and a fuel injection rate of the fuel injection pump is controlled based on the fuel injection target value. At the same time, a displacement volume target value of the hydraulic pump is determined based on at least the engine speed deviation and an actual discharge pressure of the hydraulic pump in such a manner that as the engine speed deviation increases an input torque of the hydraulic pump decreases, and the displacement volume of the hydraulic pump is controlled based on the displacement volume target value.

Integral hydraulic blocking and relief valve

Abstract: An integral hydraulic blocking and relief valve (12) for use in an aircraft night power actuator (60) includes a unique stepped piston assembly (PA and PB) referenced to return or relieve system pressure (P) at the same, predetermined level, independent of any influence due to the system pressure (P), and control valve means (20) for controlling hydraulic system fluid to the hydraulic blocking and relief valve (12) for actuating the night power actuator (60).

Hydraulic power system

Abstract: A hydraulic power system having a variable displacement hydraulic pump, a hydraulic motor driven by the hydraulic pump for actuating a load, the pump and motor being connected to constitute a closed hydraulic circuit, hydraulic servo for controlling the displacement volume of the pump, and motor stopping device including a brake arrangement adapted to release the motor from a braked condition when a control pressure from a hydraulic fluid source is received. The system includes a control valve responsive to a main line pressure in the closed hydraulic circuit for controlling a hydraulic fluid supply to the servo to prevent the main line pressure from substantially exceeding a predetermined level, first pressure transmission control interlocked with an input of the servo for transmitting the control pressure to the brake arrangement when the input is actuated, and a second pressure transmission control responsive to the pressure of a hydraulic fluid supply to the servo on the output side of the control valve for transmitting the control pressure to the brake arrangement when the supply pressure is substantially lower than a normal supply pressure of the hydraulic fluid source.

Oil well pump driving unit

Abstract: An oil well pumping apparatus which includes a submerged reciprocating pump mounted in a tubing arrangement communicating with the well head, a sucker rod string extending through the tubing arrangement and connected in driving relation with the pump, and a pumping tee and stuffing box arrangement mounted on the casing of the well at the well head and including a sealed drive rod arrangement in the stuffing box connected in driving relation to said sucker rod string, and a pump driving unit. The pump driving unit includes a hydraulic cylinder and support means for supporting the hydraulic cylinder over the stuffing box with the axis of the cylinder rod aligned with the axis of said stuffing box. A coupling means is provided for coupling the cylinder rod to the seal drive rod arrangement. A hydraulic drive-control unit is coupled to said in-out fluid line for operating the hydraulic cylinder to produce an operating cycle consisting of a hydraulic power upstroke and a gravity power downstroke.

Engine retarder hydraulic reset mechanism

Abstract: An hydraulic reset mechanism is provided for an engine retarder of the compression relief type. The mechanism senses the force required to hold open an exhaust valve. When this force has decreased substantially from the force required to open the exhaust valve initially, a valve is opened in the hydraulic system to release the hydraulic pressure and permit the exhaust valve to close. The mechanism assures that the engine exhaust valves are closed, or substantially closed, prior to the normal opening of the exhaust valves at the end of the power stroke of the engine without affecting the retarding horsepower produced by the engine brake.

Pull type installation tool

Abstract: An improved pneumatic-hydraulic actuated single action pull type installation tool for installing pull type fasteners is disclosed which includes a continuously pressurized fluid reservoir operative to maintain a minimum positive pressure on the hydraulic circuit during operation so as to protect the integrity of the hydraulic circuit during normal operating pressure fluctuations and to reduce the possibility of air being drawn into the hydraulic system during sudden pressure drops in the actuating pressure chamber which may occur at the time the pintail portion is separated from the fastener. Further, the reservoir provides a source of make up hydraulic fluid to replace any fluid which may be lost due to leakage. Suitable valves are provided to enable the reservoir to selectively communicate with both driving and return portions of the hydraulic circuit while still enabling selective pressurization thereof. Apparatus is also provided for enabling convenient and efficient refilling of the reservoir and to depressurize the reservoir such as for service. A high pressure relief valve is also provided in the circuit which is operative to vent the hydraulic system to atmosphere in the event of abnormal pressure build up.

Regenerative and anticavitation hydraulic system for an excavator

Abstract: A hydraulic system (40) for an excavator (10) which utilizes regeneration, minimizes cavitation, and provides hose break protection is disclosed. A valve assembly (50) is permanently connected to a hydraulic actuator (30) which is to be controlled. A hydraulic power supply (42) remote from the hydraulic actuator is connected to the valve assembly (50) through a pair of flexible hoses (56, 58). Pressurized hydraulic fluid can flow to the valve assembly through either of the flexible hydraulic hoses, but the valve assembly (50) includes a check valve (60) so hydraulic fluid return is only possible through one hose (56). A two position valve (62) is provided in the valve assembly (50) between a pair of operating ports (36, 38) on the hydraulic actuator (30). The two position valve (62) can be opened in response to a signal from the operator, connecting the two ports (36, 38) together to permit regeneration. The valve assembly (50) also includes a pressure relief valve (64) connected to one of the ports (38) to limit overpressure. A second check valve (66) is connected around the pressure relief valve (64) to permit hydraulic fluid to flow from a reservoir (43) to the hydraulic actuator (30). The reservoir (43) is pressurized at a relatively low pressure, so when the pressure at the associated port (38) drops below the reservoir pressure hydraulic fluid flows through the second check valve (66) to the port (38) and minimizes cavitation.

De-aerator for hydraulic power units

Abstract: Provision is made for removing gaseous impurities, such as air, from hydraulic fluid in a hydraulic power system. A sump tank serves as a reservoir for the hydraulic fluid which passes through the power unit in a closed loop manner. The fluid inlet and outlet lines are connected to the tank below the level of hydraulic fluid therein. A source of vacuum is connected to the tank above the fluid level for removing impurities from the fluid. In a preferred embodiment, a flexible member is used to adjust the volume of the evacuated area of the tank as a function of the pressure in the tank space above the fluid level. The tank may further include one or more adjustable expandable devices which are used to regulate the fluid pressure within the system as desired.

Hydraulic control of subsea well equipment

Abstract: A control system (10) employable for purposes of effecting the operation of a plurality of actuable devices, which are located at a subsea site, from a position that is remote therefrom. More specifically, the subject control system (10) is particularly suited for employment for purposes of hydraulically effecting the operation of the valves of a subsea christmas tree (30). To this end, the subject control system (10), on the one hand, is connected in fluid flow relation with a surface control center (16) from whence hydraulic fluid is supplied under pressure, and, on the other hand, is connected to a subsea sequence valving means (12) which receives the hydraulic fluid under pressure from the surface control center (16) and in turn transmits hydraulic power to the operators (46, 48, 50, 52, 54, 56) of the christmas tree valves to cause the latter to move in accordance with a predetermined operating program (32). The subject control system (10) is characterized by the flexibility that it possesses in terms of the diversity of operating programs (32) than can be employed therewith, by the fact that the sequence valving means (12) embodies constant force spring means (88) which enables the elimination of one hydraulic line between the surface control center (16) and the subsea site of the christmas tree (30), and by the embodiment in the subsea sequence valving means of new and improved duplex shear seal means (86) operative for preventing interflow.

Vehicle hydraulic system with pump speed control

Abstract: A lift truck is disclosed with a changeable speed electric motor for driving a single positive displacement pump to supply the power steering and various work handling hydraulic load circuits. Manually actuable selector means are operatively connected with the load circuits and a speed range control means is operatively connected with the selector means for energizing the electric motor in different speed ranges according to the actuation of the selector means. A priority demand valve is connected between the pump and the respective load circuits and supplies fluid to the load circuits, giving priority to the power steering circuit. The speed range control means includes speed regulating means for the electric motor. The motor is energized from the battery and the regulating means includes a pulsing circuit with a motor current feedback to vary the mark/space ratio of the pulses produced by the pulsing circuit.

Self-leveling and height control hydraulic system.

Abstract: An implement having a rotary flow divider (16) controlling fluid to and from at least two independent hydraulic rams (26, 28) for raising and lowering the implement in a level manner. A counter (74, 274) totals the revolutions of the flow divider and actuates an electrical circuit which controls solenoid valves (44, 46, 220) to stop the implement at the proper height.

Hydraulic control for a power transmission

Abstract: HYDRAULIC CONTROL FOR A POWER TRANSMISSION Abstract of the Disclosure: A hydraulic control for a power transmission has a regulator valve for controlling the hydraulic system pressure and a plurality of shift valves for controlling the automatic ratio change in the trans-mission. The shift valves are urged toward the higher ratio position by a governor pressure. The shift valves, except the 1-2 valve, are selectively sub-jected to separate modulated throttle valve pressures acting in opposition to the governor pressure and depending upon whether the respective shift valve is in the lower or higher ratio position. The modulated pressures are maintained at substantially zero for a portion of the throttle valve pressure range so that upshifting and downshifting will be sensitive to governor pressure and therefore vehicle speed only. The regulator valve is subject to a variable bias pressure which is proportional to throttle valve pressure. The bias pressure is controlled by a valve to be equal to the throttle pressure during the lower pressure portion of the throttle pressure range and to increase at a rate less than the throttle valve pressure during the remainder of the pressure range.

Demand type power brake system

Abstract: A hydraulic power brake system has a pump driven through a variable torque magnetic clutch by an engine-drive pulley. A rheostat controlled by movement of the brake booster push rod varies the amount of current to the clutch to control the torque transmitted to the pump. The pump pressure output varies directly with clutch torque. Pump pressure is delivered to a closed center hydraulic booster. The pump does not operate when no braking effort is required.

Fluid flow controlling device

Abstract: A fluid flow controlling device includes a flow control that is interposed between the valve spool of a directional control valve and the work port channel of the directional control valve, and that is effective to control fluid flow to and from one motor port of a fluid motor in proportion to respective sizing of first and second fluid flow paths by the valve spool. The fluid flow controlling device is preferably used in load responsive hydraulic systems.

Vehicle hydraulic power steering system with means for controlling the operation of a power steering pump

Abstract: In a vehicle hydraulic power steering system, the operation of a pump (9) for supplying a pressurized working fluid to a power steering unit (6) is controlled in accordance with an output signal of a control means (20) which is responsive to detected values of a speed of the rotation of a steering wheel and a pressure of the working fluid supplied to said power steering unit (6). The operation of the pump is initiated when the steering wheel (1) is turned at a speed of the rotation higher than a predetermined value and it is ceased when the pressure of the working fluid is reduced below a predetermined value due to the termination of a power assist operation of the power steering system.

Power assisted hydraulic control system

Abstract: The invention provides a power assisted hydraulic control system suitable for actuating clutches and brakes. The system incorporates a master cylinder having a master piston therein defining a control chamber, a hydraulic power assistance unit, and a distributor adapted to connect, by means of a slide valve, the power assistance unit with the hydraulic receiver controlling the brake or clutch unit. The distributor comprises a slide-valve having a plunger one end of which is subjected to the pressure in the control chamber and the other end of which is subjected to the pressure in the receiver. A bypass channel links the control chamber of the master cylinder to the pipeline connecting the operating port of the distributor to the receiver. The bypass channel has a bypass valve controlled by a spring which opens in the event of failure of the power assistance to permit manual operation by the master piston.

Method of controlling internal combustion engine and hydraulic pump system

Abstract: A method of controlling a system for generating hydraulic power, which comprises an internal combustion engine (1) controlled by the fuel injection of a fuel injection pump (6), and a plurality of variable volume hydraulic pumps (2, 3) driven by the internal combustion engine. A rotating speed deviation (Alpha)N is obtained by the difference between a predetermined rotating speed Nr set by the accelerator stroke of the internal combustion engine (1) and an output rotating speed N. This deviation (Alpha)N is convened into a pump control coefficient Kp which is the function of this deviation, the coefficient Kp and the operating amounts L1, L2 of the rotated slant plates of the pumps are calculated, and the calculated values are applied as a predetermined slant plate-tilting values X1i, X2i of the pump to the regulators (4, 5) of the pumps (2, 3) to control the slant plate-tilting angles of the pumps. Simultaneously, the deviation (Alpha)N is converted into the rack displacement object value M having the function of the deviation. The rack displacement of the fuel injection pump (6) is controlled by the convened value M to control the fuel injection amount of the internal combustion engine.

Electronic controller of hydraulic pressure for journal loading of bowl mill

Abstract: An electronic system particularly suited for effecting control over the pressure of the hydraulic fluid through which the journal loading is established on the grindling rolls (20) of a bowl mill (10) of the type that is employed to pulverize coal. The subject electronic system is operatively connected in circuit relation to the belt feeder means (12), located externally of the bowl mill (10), that supplies to the bowl mill (10) the coal that is to be pulverized therein. In addition, the subject electronic system is also operatively connected in circuit relation to the hydraulic power unit (22) of the bowl mill (10) that provides hydraulic fluid under pressure to the grinding rolls (20). Accordingly, the subject electronic system is operative to monitor both the rate at which coal is fed to the bowl mill (10) and the pressure of the hydraulic fluid supplied to the grinding rolls (20) such that as the feed rate of the coal varies the hydraulic pressure being applied to the grinding rolls (20) can be made to vary so that the grinding forces that the grinding rolls (20) exert can be maintained substantially as an optimum regardless of the rate at which the coal is being fed to the bowl mill (10).

Hydraulic circuit for hydraulic power shovel

Abstract: PURPOSE:To accomplish speeding up in a single travelling operation, smooth and accurate actions individually in the simultaneous slewing and travelling operation and to obtain higher efficiency for each working in the modes of operation other than travelling CONSTITUTION:Equal delivery pumps of large capacity are used for the first and the fourth pumps 1 and 4 while equal delivery pumps of small capacity are used for the second and the third pumps In a single travelling operation, alone, the fluids discharged from the first and the second pumps 1 and 2 flow together to the travelling motor 84 and those from the third and the fourth pumps 3 and 4 flow together to the motor 85 separately whereby the travelling speed is increased In the simultaneous slewing and travelling operation, the fluid discharged from the fourth pump flows to the tank 18 while the fluids from the first, the second and the third pumps 1-3 are fed to the slewing motor 81 and right and left motors 84 and 85 independently In other mode of operation, fluids from four pumps 1-4 is effectively utilized in the low pressure range to speed up the actuator, and in the high pressure range, with the unloading of the forth pump 4, the fluids discharged from the other three pumps are adequately utilized

Cooling system of working fluid

Abstract: PURPOSE:To operate an oil hydraulic system always in a high efficient condition, by separately providing an oil cooler cooling fan from a radiator cooling fan, driving the oil cooler cooling fan through an oil hydraulic motor and stopping said oil hydraulic motor for working fluid at low temperature. CONSTITUTION:An oil cooler 4 is provided in a different position from that of a radiator 3 and cooled by a fan 6. Said fan 6 is driven by an oil hydraulic motor 7 driven by an oil hydraulic pump 8. When working fluid is in a state of high temperature, a solenoid selector valve 11 is closed, and the oil hydraulic motor 7 is driven to rotate the fan 6, then the oil cooler 4 is cooled to hold the working fluid to an adequate temperature. If temperature of the working fluid decreases, an oil temperature detector 13 is operated to open the solenoid selector valve 11, and the pressure oil is returned to a tank 12 through a bypass flow line 10, then the oil hydraulic motor is stopped to cease cooling operation of the fan 6.

Method for controlling a hydraulic power system

Abstract: A method and an apparatus for controlling a hydraulic power system comprising internal combustion engines (1, 120) to which fuel is supplied by fuel injection pumps (6,170) and at least one variable volume type hydraulic pump (2, 3; 124, 126). The rpm deviation (AN) is obtained from the difference between a target rpm number (Nr) set by the amount the accelerator of the internal combustion engine is opened and the output rpm (N.) of the internal combustion engine. Then, a fuel injection amount target value (M) having a predetermined relationship with the deviation is obtained based at least on the deviation (N), and the amount of fuel injected by the fuel injection pump (6, 170) is controlled based on the fuel injection amount target value (M). Simultaneously, the displacement volume target value (X) ot the hydraulic pump is so determined as to reduce the input torque of the pump as the deviation (AN) increases based at least on the deviation (AN) and the actual discharge pressure (P) of the pumps (2, 3; 124, 126) and the displacement volume of the pump is controlled based on the displacement volume target value (X).

Log sawing apparatus

Abstract: A hydraulically powered treelength log sawing apparatus has a log support lined with teeth opposing the outwardly-directed sawing force generated by its driveshaft-pivoted chainsaw. The chainsaw is driven by a hydraulic motor whose fluid exhaust flows through a conduit to an adjustable restriction which creates a backpressure in the fluid in the conduit. The magnitude of the backpressure is directly related to the speed of the motor and the saw, and the backpressure is directed to a hydraulic cylinder which forces the chainsaw into sawing engagement with logs on the support, thereby prevent stalling of the saw and in general causing the saw speed and engagement force respectively to be self-compensating and requiring no attention from the operator during sawing. An arrangement of automatic valves and bypass conduits removes the power from the motor and reverses the hydraulic cylinder to disengage the saw from the logs upon simple reversal of the inlet and outlet or exhaust connections between the motor and cylinder and the hydraulic power supply, as by shifting a four-way valve which passes the pressurized and exhaust fluid flows to the apparatus.

Hydraulic pump drive system for an automotive vehicle

Abstract: A hydraulic pump drive system for an automotive vehicle employing a starter motor to drive the hydraulic pump. The drive shaft of the starter motor is connected to the impeller of the pump, and can be engaged to the engine flywheel to start the engine. A control circuit is provided to connect the armature and the field winding or field windings of the starter in series for starting the engine and in parallel after the engine has been started. The control circuit also controls a valve in the hydraulic system which acts as a pressure-relief valve to minimize load due to the hydraulic pump on the starter motor during engine starting.

Actuating magnet for a hydraulic valve

Abstract: An actuating magnet, in particular a direct-current actuating magnet, for a hydraulic valve has a magnet housing (1 to 4, 12), in the accommodation space (16, 17) of which an armature (15) is accommodated so as to be movable in a reciprocating manner. The armature (15) subdivides the liquid-filled accommodation space into two sections. So that a retarding device connected between the actuating magnet and the hydraulic valve can be dispensed with, at least one restrictor (25) is provided between the two sections of the accommodation space.

Fluid control system.

Abstract: The invention relates to a hydraulic system for the control of an actuator consisting of a double acting cylinder and piston unit. The control system comprises a bi-directional pump C the opposite outlets C1 and C2 of which are connected respectively with the opposite ends of the cylinder B through a one-way pressure check valve D1. Each end of the cylinder is also connected with a hydraulic reservoir G through a check valve E1 which is also connected with the respective pump outlet C1 so as to close in response to a predetermined increase in the hydraulic pressure between the pump outlet C1 and its respective one-way pressure check valve D1.

A guide to the planning and hydraulic design of jet pump remedial sand bypassing systems

Abstract: From abstract: This report is intended as an aid to engineers studying alternative solutions to a coastal sand bypassing problem.

High pressure hydraulic systems

Abstract: In a high pressure hydraulic system a source supplies pressurized fluid to a slave unit through a control valve operative to maintain the slave unit in a desired condition. Leakage from the slave unit past the control valve when the source is inoperative is undesirable, but it is difficult to provide durable leakproof seals and to minimize valve operating forces at high fluid pressures. The control valve therefore comprises two solenoid-operated valves oppositely acting and arranged in series between the source and the slave unit, each valve being closed to prevent flow through the valve in a direction from the other valve and opened to permit flow in both directions, under the control of a solenoid and the pressure differential acting across the valve, a seating portion on a first valve is of elastomeric material to provide a leakproof seal when that valve is closed. In the construction shown the slave unit is an hydraulic suspension strut, and the system is adapted as a vehicular suspension levelling system, with the valves and the source being manipulated as required by an electronic control system.

Rotary hydraulic device

Abstract: A rotary hydraulic device in which a pair of delivery ports of a vane pump communicate with independently separated delivery chambers, respectively, and the communication between one of the delivery chamber and a hydraulic machine is shut off after the flow rate of delivery fluid from the delivery port exceeds a certain level with the increase in the speed of rotation of the pump. The excess fluid from the delivery port is returned to the tank side which causes the decrease of the supply flow rate in the zone of high speed rotation of the pump and also the reduction of power consumption so that the rotary hydraulic device of the invention is especially suitable for the power steering devices of vehicles.

Method and flushing for removing hydraulic fluid from hydraulic systems

Abstract: A method for removing residual hydraulic fluid from hydraulic systems employing a flushing fluid comprising a thickening agent dissolved in an organic solvent having a boiling point below about 125° C. After draining fluid from a hydraulic system, flushing fluid is injected into the system and circulated to dissolve residual fluid. The flushing fluid, containing dissolved residual fluid, is then drained from the system. In a preferred embodiment, the flushing fluid comprises about one to three percent by weight ethyl cellulose dissolved in 1,1,1-trichloroethane together with about 0.1 to six percent by weight of a friction-reducing antiwear additive.