Other

Caterpillar Inc.

Caterpillar Tractor Co.

Fluid Power Components, Inc.

Klf Patents, Inventions, and Marketing Corporation Limited

Tadeusz Budzich

Harold Gold

Stanislaw Filip

Exhaust pressurizing circuit including flow amplification

Negative load control and energy utilizing system

Fluid systems having fluid motors which control aiding type loads many times have problems with cavitation in one end of the fluid type motor during lowering thereof. It is desirable to eliminate all cavitation in the fluid motor during operation. In order to eliminate cavitation during lowering of an aiding type load and to provide a positive pressure therein, the subject arrangement provides an exhaust pressurizing control for use in a fluid system. The exhaust pressurizing control includes an exhaust manifold means having selector means to provide a positive pressure in the exhaust manifold means during lowering of an aiding type load. The selector means includes pressure limiting and unloading means operative to provide a positive pressure in the exhaust manifold means during lowering of the aiding type load and to unload the pressurized fluid in the exhaust manifold means during raising of a resisting type load. The pressurized fluid in the exhaust manifold means is available to the fluid motor through anti-cavitational valve means. This arrangement effectively eliminates cavitation in the fluid motor.

Exhaust pressurizing control for a fluid system

A load responsive control system using on a selective basis the energy derived from a negative type load for operation of system controllers, which may be of various types, including electro-hydraulic multi-stage controls, for use in positioning of the main control spools and in control of other system components.

Load responsive control system adapted to use of negative load pressure

A load responsive system having at least one direction and flow control valve, the flow control of which is accomplished in response to a control signal above a certain predetermined pressure level and a fixed displacement pump, provided with a bypass type output flow control, operable to maintain a constant pressure differential between pump discharge pressure and load pressure of the load controlled by the direction and flow control valve. The output flow control is provided with an unloading control, which maintains the discharge pressure of the pump at any preselected minimum pressure level once the control signal transmitted to the direction and flow control valve drops below a certain minimum predetermined pressure level signifying that the system is in standby condition.

Load responsive system using load responsive pump control of a bypass

A load sensing circuit of a load responsive direction control valve including a device for sensing load pressure signals, identifying those pressure signals as positive or negative and transmitting those identified positive or negative load pressure signals to the throttling compensator controls of the load responsive valve. The load pressure signal identifying circuit responds to the control pressure signals, which determine the desired direction of displacement of the spool of the direction control valve, while those control pressure signals are selectively isolated from the identifying circuit, in response to the direction of spool displacement from its neutral position.

Control signal blocking direction control valve in load-sensing circuit

A load sensing circuit of a load responsive direction control valve including a device for sensing load pressure signals identifying those load pressure signals as positive or negative and transmitting those identified positive or negative load pressure signals to the throttling compensator control of the load responsive valve, while also transmitting the positive load pressure signal to the pump control. The load pressure signals from individual cylinder ports, together with the signals related to the direction of displacement of the controlled load, are transmitted electrically to an electrical logic circuit, which identifies the load pressures as positive or negative and generates the required electrical signals to the electrohydraulic controls, which connect the positive or negative load pressure to throttling compensator controls of the load responsive direction and flow control valve.

Load sensing circuit of load compensated direction control valve

A load responsive system is provided with two synchronizing systems for positive and negative load compensation. One of the synchronizing systems varies the flow through a negative load compensator, during control of a negative load, in response to the inlet pressure of a fluid motor which is controlled by a positive load compensator. The other synchronizing system isolates the system pump from the fluid motor during control of the negative load while make-up flow to the fluid motor is supplied from the fluid exhaust system. In a more specific arrangement, the system pump is isolated from the fluid motor through the use of the positive load compensator and totally independent of any negative load compensating action. The synchronizing systems function in response to an external signal(s), which can be a function of any selected specific parameter of the system.

Load responsive system having synchronizing systems between positive and

A fluid fuse is quickly operable to shut off fluid flow upon rupture or other failure of fluid conducting line or other structural member downstream of the fuse. The fuse is actuated during decompression fluid flow resulting from decompression of fluid and elastic contraction of structural components downstream of the fluid fuse. During decompression fluid flow, a valve member is moved from an open position to a closed position by two forces generated by a pressure differential caused by sudden decompression of the fluid and developed across two variable, sharp edge, viscosity insensitive orifices, positioned in series and separated by a flow cut-off and sealing surface. The closing force, generated by the pressure differential of the upstream orifice is dominant and increases with the displacement of the closing member in a predetermined manner, permitting the use of a high preload and high rate opposing spring, at relatively low pressure differentials. The sealing surface of the fuse is provided with limited freedom of alignment to permit tight sealing. The fuse assembly includes a manually adjustable bypass arrangement and a pressure peak attenuating control.

Hydraulic fuse valve assembly

A load responsive system including individual positive and negative load compensators, for control of positive or negative load and an external logic system for determination of whether the controlled load pressure is positive or negative. The deactivating valve deactivates the positive load compensator, when the negative load pressure exceeds a certain minimum predetermined level, preventing flow of fluid from the system pump to the system actuator controlling a negative load at a pressure higher than a certain predetermined level, and therefore preventing development of excessive pressure in the actuator, while also deactivating the negative load compensator below a certain minimum predetermined negative load pressure level and while the positive load is being controlled by the positive load compensator.

Load compensated valve

A compensated control valve assembly for control of fluid flow to and from a fluid motor, which may be of a cylinder type and is subjected to positive and negative loads. During control of negative load the controlled pressure level of a pressure reducing valve mechanism handling the fluid flow at negative load pressure is varied upstream of an outflow metering orifice arrangement, positioned at the outlet of the fluid motor, in response to pressure at the inlet of the fluid motor, while maintaining this controlled pressure constant at each specific level. The pressure differential across an inflow metering orifice arrangement, positioned at the inlet of the fluid motor, is maintained at a constant preselected level by a positive load pressure compensating control device.

Compensated fluid flow control valve

A centrifugal filter separator system operable to separate from oil under pressure, contaminants and water. The centrifuged water port of the centrifugal filter separator of the system is coupled to a differential pressure responsive, sensor control, which automatically senses the presence of a layer of centrifuged water against the internal surface of the rotating drum of the centrifugal separator. The sensor control is coupled to a flow control circuit which in conjunction with the differential pressure sensor control causes automatic removal of an existing layer of centrifuged water from the rotating drum via the water exit port of the separator. When there is no adequate depth layer of centrifuged water on the inner surface of the rotating drum, the sensor control deactivates the water removal circuit, while the flow control circuit maintains a minimum generally constant flow of liquid from the water port of the separator for priming purposes. The flow control circuit is coupled to a pressurized gravity type separator in the system from which separated oil is returned back to the centrifugal filter separator. The gravity separator includes an inverse relief valve circuit for replenishing water evacuated from the gravity separator, with oil from the pressure port of the system pump.

Water-oil separating system including centrifugal type separator and

A compensated direction flow control valve assembly for control of fluid flow to and from a fluid motor, which may be of a cylinder type and is subjected to positive and negative loads. During control of negative load, the negative load compensating control varies the level of the pressure differential across a metering orifice, positioned at the outlet of the fluid motor, in response to pressure at the inlet of the fluid motor, while maintaining this pressure differential constant at each specific level. The pressure differential across a metering orifice, positioned at the inlet of the fluid motor, is maintained at a constant preselected level by the positive load compensator control assembly.

A two stage relief valve, in which the pilot flow is limited by an active flow control element to a specific maximum predetermined level, to extend its maximum operating pressure range and to improve its operating characteristics. The downstream orifice may be fully open and of a fixed area type, or may be controlled by a spring or solenoid biased member. With the downstream orifice solenoid or stepper motor operated, the relief pressure level becomes responsive to an electrical input signal.

Pressure regulating and on-off valve

A compensated direction flow control valve arrangement provided with a direction control spool for control of fluid flow to and from a fluid motor, which may be of a cylinder type and is subjected to positive and negative loads. During control of negative load the upstream of the outflow metering orifice, positioned at the outlet of the fluid motor, is maintained at a controlled constant pressure level by a pressure reducing valve handling the fluid flow at negative load pressure. The outflow metering orifice is made independent of the direction control spool and its effective flow area is made responsive and varies with the pressure at the inlet of the fluid motor. The pressure differential across a metering orifice, positioned at the inlet of the fluid motor, is maintained at a constant preselected level by the positive load compensator.

Growing community of inventors

Moreland Hills, OH, United States of America

Tadeusz Budzich