Industrial system with synthetically commutated variable displacement fluid working machine

Patent metadata

Field	Value
Publication number	US-10180135-B2
Application number	US-201515507964-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Sep 30, 2014
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

An injection molding system, water jet cutting machine or other industrial system has a synthetically controlled variable displacement fluid working machine which outputs hydraulic fluid to one or more fluid consumers, such as rams or hydraulic motors, through hydraulically stiff fluid retaining volumes and receives hydraulic fluid back from one or more fluid consumers through the same or other said hydraulically stiff fluid retaining volumes. Individual piston cylinder assemblies can be allocated to different outputs. There may be no valve between the machine and the consumers. A working chamber of the machine can be caused to undergo a motoring cycle to enable the machine to output more power than is received from a motor driving the machine. An accumulator can be used to provide a source of hydraulic compliance. The machine can be controlled using pressure control, flow control, feed forward control or variable power/variable power limit control.

First claim

The invention claimed is:

1. An industrial system comprising:
a hydraulic fluid working machine, a controller for controlling the at least one fluid working machine, at least one fluid consumer and a hydraulic circuit,
the fluid working machine comprising a plurality of working chambers of cyclically varying volume, a rotatable shaft which rotates in phase with the cyclically varying volume of the plurality of working chambers, each said working chamber operable to displace a volume of working fluid which is selectable by the controller on each cycle of working chamber volume,
wherein the hydraulic circuit comprises at least first and second fluid retaining bodies,

wherein the fluid circuit directs hydraulic fluid outputted from the fluid working machine to at least one said fluid consumer via the first or second fluid retaining body, and further directs hydraulic fluid from at least one said fluid consumer to the machine via the first or the second fluid retaining body, characterised in that
the machine is operable in a pumping mode to supply energy in the form of pressurised fluid flow to at least one said fluid consumer via one of the fluid retaining bodies in order that at least one said fluid consumer may perform work, and the machine is also operable in a regeneration mode operating as a motor such that it receives energy by way of pressurised fluid flow from at least one said fluid consumer via one of the fluid retaining bodies and converts it to fluid working machine shaft torque, and wherein the machine has at least two fluid outputs, whereby the piston cylinder assemblies which provide the drive mechanism of the machine can be dynamically allocated to the fluid outputs such that the fraction of assemblies allocated to each output is variable during machine operation.

2. An industrial system according to claim 1 , where at least one of the fluid retaining bodies is hydraulically stiff.

3. An industrial system according to claim 2 where the volume of the at least one fluid retaining body changes, when varying flow between zero flow and operating pressure or high pressure flow either by less than 2%, or the required number of machine piston stroke cycles producing a variation in flow between zero flow and operating pressure or high pressure flow is less than or equal to five.

4. An industrial system according to claim 1 , where there is no valve hydraulically intermediate the fluid working machine and one or more said fluid consumer, which would otherwise function to check and/or divert flow, and there is no cross line relief between portions of the circuit.

5. An industrial system according to claim 1 , further comprises at least one additional fluid working machine comprising a plurality of working chambers of cyclically varying volume, a rotatable shaft which rotates in phase with the cyclically varying volume of the plurality of working chambers, each said working chamber operable to displace a volume of working fluid which is selectable by a controller on each cycle of working chamber volume, wherein the fluid working machine and the additional fluid working machine are in fluid communication with different fluid consumers.

6. An industrial system according to claim 1 comprising an additional valve located within the circuit to isolate the fluid volumes, where the valve may switch to a position which checks the flow of fluid through at least one of the two fluid volumes.

7. An industrial system according to claim 1 wherein at least one said consumer is a ram, or a hydraulic motor.

8. An industrial system according to claim 7 where the torque arising from at least two cylinders in the machine may be mutually supportive, or the torque may be subtractive.

9. An industrial system according to claim 8 , where the fluid working machine is driven by a motor and wherein the controller is programmed to selectively cause at least one working chamber of the fluid working machine to carry out a motoring cycle to enable the power output of the fluid working machine to thereby exceed the power received by the fluid working machine from the motor.

10. An industrial system according to claim 8 , where the said motoring cycle is carried out using working fluid received from at least one accumulator, and using some of the piston cylinder assemblies of the fluid working machine to provide a service that provides flow to and from the at least one accumulator.

11. An industrial system according to claim 1 , where the machine is a synthetically commutated pump-motor that may function as a pump and/or a motor.

12. An industrial system according to claim 11 where the machine additionally comprises working chambers which are mechanically commutated.

13. An industrial system according to claim 1 , where a hydraulic accumulator is fluidly connected or (typically selectively) connectable to at least one said fluid retaining bodies between the machine and the consumer, in order to (optionally selectively) provide a source of hydraulic compliance.

14. An industrial system according to claim 1 , further comprising a plurality of manifolds, where the machine comprises a plurality of valves, each of which is operable to regulate the flow of fluid between a working chamber of the machine and at least one of the manifolds.

15. An industrial system according to claim 1 which is an injection moulding machine.

16. An injection moulding machine according to claim 15 , wherein at least one said fluid consumer is a motor configured to rotate a screw member in a barrel for injecting moulding material into a mould cavity.

17. An injection moulding system according to claim 16 where the fluid consumer is coupled to said injection unit for translating said screw in a barrel pursuant to a variable translate command signal.

18. An injection moulding machine according to claim 15 , where the consumer is a ram configured to actuate a clamp unit for supporting first and second sections of a mould selectively movable from a parted position in which said mould sections are opened to a moulded position in which the mould sections are closed to define said mould cavity therebetween.

19. An injection moulding system according to claim 18 where the fluid consumer is an ejection ram, injection unit translating ram or rotating motor, tie-bar clamp ram, or any hydraulic consumer in the function of an injection moulding system.

20. An industrial system according to claim 1 which is a water jet cutting machine.

21. A water jet cutting machine according to claim 20 , comprising at least two fluid working machines and at least two said fluid consumers being pressure intensifiers ( 451 , 452 ) with ganged outputs, one fluid machine output is commanded to return one pressure intensifier piston at a greater speed than the other next-in-phase pressure intensifier piston is extended, where towards the end of the stroke of one intensifier, as it slows down the next-in-phase intensifier starts to move, thus taking over as the dominant contributor to the ganged flow in order to maintain constant flow, the returning intensifier must return and start moving before the other intensifier is at the end of its stroke.

22. A water jet cutting system according to claim 20 wherein at least one said fluid consumer is a pressure intensifier.

23. A kit of parts which can be assembled to form an industrial system according to claim 1 .

24. A method of controlling an industrial system according to cl

Assignees

• Artemis Intelligent Power Ltd

Inventors

• Caldwell Niall James
• Edmondson Jeremy
• Robertson Alasdair Ian Fletcher
• Stein Uwe Bernhard Pascal

Classifications

• F15B2211/214

  the pressure sources being hydrotransformers · CPC title

• F15B2211/27

  Directional control by means of the pressure source · CPC title

• F15B11/0426

  by controlling the number of pumps or parallel valves switched on · CPC title

• F04B1/06 Primary

  Control · CPC title

• F04B49/22 Primary

  by means of valves (F04B49/03 takes precedence) · CPC title