WO2004097227A1

WO2004097227A1 - Valve

Info

Publication number: WO2004097227A1
Application number: PCT/GB2004/001879
Authority: WO
Inventors: Hugh Christopher Bramley; Richard Nighy; Alan Bhimani
Original assignee: Imi Vision Limited
Priority date: 2003-05-01
Filing date: 2004-04-30
Publication date: 2004-11-11
Also published as: GB0523476D0; GB2416604A; GB2416604B

Abstract

A fluid flow control valve island (9), for example for use in sequentially controlling pneumatic actuators of automated production machinery, comprises a plurality of sets (one of which is designated 14) of four bistable 2/2 control valves a, b, c and d, a programmable controller (10) which processes control signals from an external programmable logic controller (PLC) (11), and a memory element (13). The controller (10) is pre-programmed with a program downloaded from an external PC (12) and stored in the memory element (13), the program identifying the respective predetermined valve type to be simulated by each set of 2/2 valves a, b, c and d. The controller (10) generates from signals from the PLC (11) respective outputs to each of the four valves a, b, c and d in a set so as to actuate one or more of those four valves and thus switch that set from one mode of the predetermined valve type simulated to its other, or another, mode. The invention thus provides a universal valve island that may be programmed by the manufacturer or the user to simulate a multitude of selected, differing, valve types, including 2/2 NO or NC, 3/2 NO or NC, 5/2, 5/3 COP, 5/3 COE and 5/3 APB types without having to mechanically reconfigure the valves on the island (9).

Description

Valve

This invention relates to fluid flow control valves and more particularly to valves for controlling fluid powered devices such as, for example, cylinders and grippers commonly used in the automation of production processes. The invention is applicable for use with any fluid medium but for convenience, but not by way of limitation, this specification refers largely to pneumatic devices.

It is commonplace in industrial applications to have a number of pneumatic devices controlled by a number of valves, all connected to one electronic controller that controls and synchronises the switching of the valves so that the devices operate in the desired sequence. These valves are commonly grouped together in a block of valves with a common supply of air and a common exhaust of air. Such blocks of valves are commonly referred to as 'valve islands' and are available from a number of suppliers.

Valve islands are generally made to order for a specific application and commonly will consist of a plurality of valve types of different operating functions, e.g. 2/2 (two air ports, two possible positions) 3/2 (three air ports, two possible positions) available as normally open (NO) or normally closed (NC) valves, 5/2 (five air ports, two possible positions) and 5/3 (five air ports, three possible positions), the 5/3 type taking one of three forms, centre open to exhaust (COE), centre open to pressure

(COP) or all ports blocked (APB) . A customer may order a valve island with any combination of varying numbers of the above valve types, resulting in made to order products and thus in long lead times and increased logistics and records associated with made to order products. An attempt to mitigate these problems with some success is disclosed in the PCT application WO 02/38966. One problem associated with the technology disclosed in this document is that, while any one or more of the valves may be set up to provide a particular valve type, it is not possible to achieve another type electronically without mechanically reconfiguring the valve island.

It is an object of the present invention to solve or at least mitigate that problem so as to provide a more versatile valve island.

According to the present invention there is provided a fluid flow control valve island for controlling the operation of a fluid-operated system, the valve island comprising a plurality of sets of four, electrically operable bistable 2/2 valves, the valves in each of said sets being independently operable in response to a control signal, specific to a set, fed, in use, to the valve island such that, as a set, they simulate a predetermined valve type, and electronic circuitry for receiving each said control signal and including processing means programmed or programmable to process the control signal to produce respective output signals for simultaneously acting on the valves in a set thereby to cause the set to simulate the predetermined valve type.

The output signals produced by the processing means in response to a control signal received from, for example, a programmable logic controller of the type commonly used to control the sequence of operation of machinery actuators, such as pneumatic cylinders, may cause the respective valves in each set to change position or maintain a prevailing position as the case may be depending on the valve type that a particular set is arranged to simulate. By "programming" the processing means appropriately for each set of four 2/2 valves, the sets may independently be arranged to simulate virtually any valve type, including, in particular, the 5/3 COE, COP and ABP types referred to above. Preferably, the valve island is capable of being re-programmed by the user in the event that a change in any one or more of the predetermined valve types is required.

Preferably, the valves are very fast switching bistable valves requiring zero or minimal external power requirement to hold the valves in either of their two positions, thus reducing the power consumption of the valve island. Preferably the valves are of the type using permanent magnetic means to hold the valve armature latched in either of its bistable positions whereby the position of each valve may be changed by means of a single electrical pulse. For example, an electromagnetic coil may be associated with the armature such that the position of the armature can be changed by the application of a single electrical pulse to the coil.

Preferably, there is some electrical circuitry with an associated power storage means which upon a power failure to the valve island, has enough stored power to safely return all the valves to respective predetermined positions to effect a fail safe mode. Preferably the power storage means takes the form of a capacitor or battery, preferably of the rechargeable type.

In a preferred arrangement, each array of four valves is housed in a body, having a section of ducting for supply and at least one section of ducting for exhaust formed through the body and two outlets from the body such that a valve 'slice' is effected whereby a number of these valve slices may be assembled together to form a valve island with common supply and exhaust ducts passing therethrough. In another preferred arrangement a single block is formed having a section of ducting for supply and at least one section of ducting for exhaust formed through the body and which houses a number of arrays of four 2/2 valves, each array having two associated outlets. Preferably each block contains four arrays each having four 2/2 valves.

In a preferred arrangement, each set of four valves is independently programmable by a plurality of manually-operable, selectable-output electrical switches, the output of these switches or combination of outputs of these outputs being used to determine the functionality of each set of valves. Preferably the output of these switches comprises the inputs to a controller to signal to that controller the functionality of each set of valves. Preferably the switches are dip switches.

In another preferred arrangement, each valve island is provided with associated electronics which consists, in part, of a programmable controller, suppliable with an electric input from a computer, palmpilot, or the like which can input information into the controller and which is stored therein to determine the functionality of each valve set. Alternatively the information may be stored in a separate memory component in electronic communication with the controller. Preferably, the information stored in the controller consists at least in part of a lookup table of the various states that each valve in a set must have in order for that set to simulate the different states of a particular valve type.

In an alternative preferred arrangement, the information stored in the controller consists at least in part of an algorithm to calculate required outputs from the controller to the valves in each set based on inputs to the controller. In another preferred arrangement, the valve island is continually reprogrammable as desired whereby the predetermined valve type of each set of 2/2 valves may be altered from time to time.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic diagram of a set of four 2/2 valves of a valve island of the invention;

Figure 2 is a schematic diagram of a valve island and associated control circuitry of the invention;

Figure 3 is a logic table showing the requisite states of each 2/2 valve in a set for the set to simulate various valve types;

Figures 4a and 4b are schematic diagrams showing the two switched modes of the 2/2 valves for simulating a 5/2 valve;

Figure 5 is a partially cut away diagram of a valve slice of a valve island of the invention; and

Figure 6 is an exploded perspective diagram of a valve island of the invention.

Referring to Figure 1, this shows a schematic diagram of a set of four 2/2 valves a, b, c, d communicable with a compressed air supply 1 via ducting 2 and vents (or "exhausts") 3 and 4 via ducts 5 and 6. The valves a, b, c, d control the flow of air between supply, exhaust and outlets 7 and 8 connected to, for example, a double acting pneumatic cylinder (not shown) . The valves a, b, c, d together represent the equivalent of a 'slice' of a traditional valve island which is capable of simulating any type of valve found in a conventional valve island, for example a pair of independently operable 2/2 or 2/3 valves, one 5/2 or one 5/3 valve.

Referring to Figure 2, a diagram is shown in which a valve island 9 is provided with an on-board controller 10 (for example a PC) which processes control signals received from a programmable logic controller (PLC) 11, and specific to each set of 2/2 valves, in accordance with a program downloaded into the controller 10 from a PIC (programmable integrated circuit) 12 and stored in a memory element 13. The program stored in the memory element 13 identifies the predetermined valve type that each set 14 of four 2/2 valves a, b, c, d is required to simulate. The controller 10 generates from each control signal respective outputs to each of the four valves a, b, c, d in a set so as to actuate one or more of those four valves and thus switch that set from one mode of the valve that the set is simulating to another, or the other, mode of the valve that the set is simulating.

Referring to Figure 3, a logic table is shown illustrating the various positions of the four 2/2 valves required to simulate various valve types. In the table, 0 represents a blocked flow path and 1 represents an open flow path. X indicates that the path in question may be open or closed i.e. if looked up as a logic table that part of the table is ignored. For each valve type, each line represents the possible states of the valve, -noting that the 2/2, 3/2 and 5/2 valve types have 2 positions and that the 5/3 valve type has 3 positions. In one method of programming the controller 10 (Figure 2) the logic table may form part of the program by means of a lookup table stored in the memory element 13 (Figure 2).

Referring to Figures 4a and 4b in conjunction with Figures 1, 2 and 3, a mode of operation is shown in which 5/2 operation of a particular set of four 2/2 valves a, b, c, d is required. A signal from the logic controller 11 is received into an input of the programmable controller 10, being a signal indicative of one state of the simulated 5/2 valve. The programmable controller 10 then references this input to the memory element 13 which identifies what valve type is to be simulated and, by means of the look up table (Figure 3) , the required state of the individual valves a, b, c, d. The programmable controller 10 then outputs a signal to the four valves a, b, c, d to switch them as necessary into their desired states identified from the look-up table. A signal referring to the first state of the valve will result in an output according to line 17 of the logic table which will output signals to switch the valves to the states shown in Figure 4a whereby air flows from supply 1 through ducting 2, through valve b and out of outlet 7 and air flows from outlet 8 through valve d, through ducting 6 to vent 3. When a signal is received by the programmable controller 10 from the logic controller 11 relating to the second state of the valve, the programmable controller will reference line 18 of the look-up table and output a signal to switch the valves a, b, c, d to the states shown in Figure 4b whereby air flows from supply 1 through ducting 2, through valve c and out of outlet 8 and air flows from outlet 7 through valve a, through ducting 5 to vent 4.

Referring to Figure 5, a slice of a valve island is shown comprising a set of four bistable 2/2 valves (and associated actuators) a, b, c, d, housed in a plastic body 15 having one inlet duct 2 and two vent ducts 5, 6 passing through it, an appendage 16 for attaching it to an adjacent valve slice and a means 17 of receiving a similar appendage 16 from an adjacent valve slice. Each slice has 2 outlets 7, 8 (one omitted for clarity) each in communication with one of the valves b, c communicating with the air supply via ducting 2 and also in communication with one of the valves a, d communicating with the vent via ducting 5 or 6. Each valve a, b, c, d has an electrical connector (not shown) for connecting it to an electronic controller, e.g. item 10 of Figure 2, for controlling the switching of the valves.

Referring to Figure 6 a valve island assembly is shown comprising two valve blocks 18, 19 containing four sets of four valves, such that each block is capable of simulating four slices of a traditional valve island, having outlets positioned on the bottom face, not shown, and supply and vent ducting running through in a similar manner to the individual slices described above. Two end blocks 20, 21 retain the valve blocks 18, 19 therebetween, each end block having ports to communicate between air supply and the supply ducting of the valve blocks. The end blocks 20, 21 mount a circuit board 22 containing electronic circuitry to drive the valves and an electric socket 23 for communication with an external control unit, two retainers 24, 25 to hold the unit together, a gasket 26 to seal the unit and a cover 27 to protect the unit.

Claims

1. A fluid flow control valve island for controlling the operation of a fluid-operated system, the valve island comprising a plurality of sets of four, electrically-operable bistable 2/2 valves, the valves in each of said sets being independently operable in response to a control signal, specific to a set, fed, in use, to the valve island such that, as a set, they simulate a predetermined valve type, and electronic circuitry for receiving each said control signal and including processing means programmed or programmable to process the control signal to produce respective output signals for simultaneously acting on the valves in a set thereby to cause the set to simulate the predetermined valve type.

2. A fluid flow control valve island according to claim 1 wherein each set of four 2/2 valves is independently programmable by a plurality of manually-operable, selectable-output electrical switches, the output of each switch, or the combination of the outputs, being used to determine the functionality of each set of 2/2 valves and thus the predetermined valve type.

3. A fluid flow control valve island according to claim 2 wherein the outputs of the switches comprise inputs to a controller for signalling the functionality of each set of 2/2 valves.

4. A fluid flow control valve island according to claim 2 or claim 3 wherein each switch is a dip switch.

5. A fluid flow control valve island according to claim 1 comprising a programmable controller for receiving information that is stored therein to determine the functionality of each set of 2/2 valves.

6. A fluid flow control valve island according to claim 5 wherein the programmable controller is adapted to receive said information from a computer such as a PC, laptop computer or a palmpilot.

7. A fluid flow control valve island according to claim 5 wherein the information is stored in a replaceable memory component in electronic communication with the controller.

8. A fluid flow control valve island according to any one of claims 5 to 7 wherein the said information comprises a look-up table of the various states that each 2/2 valve in a set must have in order for that set to simulate the different states of a predetermined valve type.

9. A fluid flow control valve island according to any one of claims 5 to 7 wherein said information comprises an algorithm for determining the required outputs from the controller to the 2/2 valves in each set based on inputs to the controller.

10. A fluid flow control valve island according to any one of claims 1 to 9 which is continually reprogrammable as desired whereby the predetermined valve type of each set of 2/2 valves may be altered from time to time.

11. A valve island according to any one claims 1 to 10 wherein each 2/2 valve is of the type comprising an armature and permanent magnetic means for holding the armature latched in either of its two bistable positions, and an electromagnetic coil associated with the armature such that the position of the armature can be changed by the application of a single electrical pulse to the coil.

12. A valve island according to any one of claims 1 to 11 comprising electrical power storage means adapted, in the event of a power failure to the valve island, to ensure that the valves adopt respective fail-safe modes.

13. A valve island according to any one of claims 1 to 12 wherein the power storage means comprises a capacitor or a battery.

14. A valve island according to any one of claims 1 to 13 wherein there is a fluid supply connection port common to the sets of 2/2 valves and at least one fluid exhaust port common to the sets of 2/2 valves.

15. A valve island according to any one of claims 1 to 14 wherein each set of four 2/2 valves is in the form of a unitary lamina ("slice"), a plurality of such slices being assembled together in side-by-side, contacting relationship to form the island.

16. A valve island according to any one of claims 1 to 14 comprising one or more unitary blocks each comprising four sets of said four 2/2 valves.