摘要:
A fluid power system comprises a pump with multiple independently variable outlets (11, 12, 13, 14), each of which is capable of delivering fluid in individually controllable volume units and a plurality of hydraulic loads (15, 16, 18, 20). A system of switching valves is configured to create fluid connections between the pump outlets and the loads. A control system commands both the pump and the switching valves, so as to create valve state combinations to satisfy load conditions as demanded by an operator. The number of pump outlets (11, 12, 13, 14) connected to one or more of the loads (15, 16, 18, 20) is changeable to satisfy the flow required of the load due to the operator demand, each pump outlet being commanded to produce a flow depending on the status of other outlets connected a load to which the outlet is connected and the operator demand for that load.
摘要:
A valve assembly suitable for regulating the flow of fluid between a working chamber of a fluid-working machine and a fluid manifold. The valve assembly comprises a valve body comprising a valve seat, a fluid passage extending through the valve body, and a travelling member comprising a valve member, which valve member is operable between an open position in which the valve member is spaced apart from the valve seat and fluid can flow through the fluid passage and a closed position in which the valve member is in sealing contact with the valve seat preventing fluid from flowing through the fluid passage. The valve assembly defining a fluid flow path passing, in a first fluid flow mode, between the valve member and the valve seat, and into the fluid passage. The valve assembly is characterized by defining a fluid flow path including a constricted flow region and further comprising a reduced pressure chamber in communication with both a first surface of the travelling member and the constricted flow region, arranged to exert a force on the travelling member by way of a pressure reduction in the reduced pressure chamber when fluid is flowing along the fluid flow path, through the constricted flow region, which force acts to resist closure of the valve. Thus, a force is generated which opposes forces acting on the valve member due to the flow of fluid past the valve member.
摘要:
A valve assembly for regulating the flow of fluid between a working chamber of a fluid-working machine and a fluid manifold. The valve assembly comprising a valve body comprising a valve seat, a fluid passage extending through the valve body, and a travelling member comprising a valve member and operable between an open position in which the valve member is spaced apart from the valve seat and fluid can flow through the fluid passage and a closed position in which the valve member is in sealing contact with the valve seat preventing fluid from flowing through the fluid passage. The valve assembly further defines a fluid flow path passing in a first fluid flow mode, between the valve member and the valve seat, and into the fluid passage. The valve assembly is characterized by a barrier upstream of the valve member, to the barrier reduces one or more forces which would otherwise act on the valve member as a result of the flow of fluid to urge the valve member towards the valve seat. Thus, one or more forces which would otherwise act on the valve member to urge the valve member to the closed position due to the flow of fluid past the valve member in the first fluid flow mode are reduced or removed. There is also disclosed a valve assembly in which fluid flowing along the said fluid flow path is incident on the downstream surface of the valve member at an angle of at least 80° to the direction in which the valve member is operable to travel between the open position and the closed position.
摘要:
The present invention provides a method of controlling a fluid working machine (12) having a plurality of working cylinders (14) having pistons (16) therein and arranged to drive a shaft (18), in which said cylinders are supplied with pressurized working fluid via a manifold (24), the contents of which may be 5 purged by a de-pressurizer taking one of a number for forms such as to allow re-activation of said machine (10).
摘要:
The present invention relates to a fluid working machine comprising a controller and a working chamber, an electronically controllable low pressure valve associated therewith and a fast high pressure valve associated therewith, characterised in that the working chamber has associated therewith a slow high pressure valve for controlling the connection of the working chamber to a secondary high pressure manifold. A fluid working machine according to the invention may be operated to rotate its shaft to a certain position, for example to allow easy maintenance of a wind turbine generator.
摘要:
A valve assembly for regulating the flow of fluid between a working chamber of a fluid-working machine and a fluid manifold. The valve assembly comprising a valve body comprising a valve seat, a fluid passage extending through the valve body, and a travelling member comprising a valve member and operable between an open position in which the valve member is spaced apart from the valve seat and fluid can flow through the fluid passage and a closed position in which the valve member is in sealing contact with the valve seat preventing fluid from flowing through the fluid passage. The valve assembly further defines a fluid flow path passing in a first fluid flow mode, between the valve member and the valve seat, and into the fluid passage. The valve assembly is characterised by a barrier upstream of the valve member, to the barrier reduces one or more forces which would otherwise act on the valve member as a result of the flow of fluid to urge the valve member towards the valve seat. Thus, one or more forces which would otherwise act on the valve member to urge the valve member to the closed position due to the flow of fluid past the valve member in the first fluid flow mode are reduced or removed. There is also disclosed a valve assembly in which fluid flowing along the said fluid flow path is incident on the downstream surface of the valve member at an angle of at least 80° to the direction in which the valve member is operable to travel between the open position and the closed position.
摘要:
An electromagnetic actuator comprises a core (1), a ferromagnetic component (2) movable in a gap (5) in the core, and a magnet (4) for attracting the component to one side of the gap. A flux concentrator (12) concentrates the magnetic flux on that side of the gap (5) and a solenoid (8) produces magnetic flux in the gap. A magnetic circuit of the solenoid is defined by part of the core (1), part of the gap (5) and by a further gap (6) between the ferromagnetic component (2) and the core (1). A demagnetiser (7) has a magnetic circuit defined by another part of the core (1), another part of the gap (5) and by the further gap (6). The demagnetiser is arranged to demagnetise the magnet (4) at least to the extent that the magnetic flux produced by the solenoid (8) is diverted from the flux concentrator (12) into the further gap (6) and the movable component (2) is movable away from the magnet (4) under the magnetic force of the solenoid (8).
摘要:
The present invention provides a cooling system such as employed in cooling a heat source and a transmission system having said cooling system integrated therewith. The cooling system further includes a pump for supplying hydraulic fluid under pressure to a motor for driving a fan employed in the cooling process. In operation, a controller initiates operation of the pump such as to supply hydraulic fluid to said motor only when needed, thereby to improve the efficiency and controllability of the cooling system.
摘要:
A zoom lens is disclosed having a zoom ratio larger than four with a field of view at the short focal length position larger than 85 degrees and with a minimal number of moving groups. The zoom lens utilizes a compound zoom structure comprising an NP or NPP zoom kernel followed by a P or PP zoom relay, with only two or three moving groups that can be used for both zooming, focusing and athermalization. An overall compact package size is achieved by the use of prisms to fold the optical path in strategic locations. An optional variable power liquid cell can provide close focusing with little or no focus breathing.
摘要:
Disclosed are techniques for the creation, communication, negotiation, and storage of promotion events between trading partners. A promotion event is managed between a retailer and a vendor each having an associated computer in communication with a data network. The promotion event is defined to include terms, including an event description and a designated items description. The terms are situated in fields of a promotion event record. The designated items description is matched to a list of items stored in an item table. This list of items is authorized for sale by the retailer. A validation operation includes determining whether the fields in the promotion event record conform to requirements of a deal sheet associated with the retailer. The promotion event record is stored as a deal in a deal transaction storage medium. The retailer computer is provided with read access to the stored deal. The retailer can then negotiate the stored deal with the vendor. The vendor can revise the terms of the stored deal as desired. Further negotiation can occur until the deal is accepted.