GB2301167A

GB2301167A - System valve

Info

Publication number: GB2301167A
Application number: GB9505146A
Authority: GB
Inventors: Elizabeth Mary Shansonga
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-14
Filing date: 1995-03-14
Publication date: 1996-11-27
Also published as: GB9505146D0

Abstract

The invention proposes a system valve for use on valve islands. The system comprises a main body 1 which houses two independent double pilot operated valves 5 and 6 common across all valve functions. An operator module 2 which is either single or double operator can be electrical or pneumatically operated. A functional gasket 3 with specifically designed tracking interfaces the operator module and the main body. A porting block 4 connects the main body to the cylinder ports. With the system covered by the invention, by a change of the functional gasket, the operation of the two independent double pilot operated valves can be co-ordinated to enable any 5/2, 5/3 or 3/2 valve function to be achieved. The interchangeability of these valve functions additionally enables a system with mixed 5/2, 5/3 and 3/2 valve functions to be produced.

Description

SYSTEM VALVE Background: 1) Field of the Invention This invention relates to a directional control valve for use primarily, but not exclusively, on valve islands. Such valve islands are used in various kinds of industrial machines utilising pressure, such as oil pressure and air pressure, but are either electrically or pneumatically operated with a separate air pressure source.

2) Description of the Related Art Directional control valves in pneumatics have been used as a "low cost" and "clean" solution to simple automation problems for many decades. These have generally been simple mechanically operated, stand alone, directly ported "in-line" valves. As the sophistication of the applications increased, so did the complexity of directional control valves.

To satisfy the need for remote control of valves, the solenoid was introduced as an electro-pneumatic interface operator. These early solenoids were crude, high power and an "add-on" to the mechanical valves. Further enhancements to applications yielded the need for multiple, remotely controlled valves per application. The solution adopted was to mount the required number of solenoid operated valves onto a single multi-station manifold, which incorporated supply and exhaust pressure pathways, to reduce the amount of piping involved. This marked the embryonic stage of what is now a fast developing and increasingly complex valve island.

Developments to directional control valves, in particular those used on valve islands have concentrated on the following areas: 1) Seal Technology Developments in seal technology have focused on optimising the product life, minimum operating pressure, leak rates, response times, air quality requirements, and tooling costs for the control valves. Various solutions are now in use with different weightings on the optimum solution.

2) Solenoid Power Requirements Power consumption of solenoids have traditionally been high, despite the perception of pneumatics as being "low cost". Developments have concentrated on optimising the power to size ratios of solenoids. Low power solenoids previously used for specialist applications are now a minimum requirement as the true cost of pneumatics is recognised. Technological changes are afoot from the use of solenoids towards bimetallic strips in an effort to achieve lower and more competitive power levels.

3) Size and Weight Reductions With the reduction in size of products being produced by automated methods, the components used in such equipment also need to be compact and light without compromising performance. In fact as the opportunity costs increase, the production cycle times required to remain competitive reduce. This increases the levels of performance expected from smaller and lighter products. Although there is a trend to improve the size to performance ratios of directional control valves, a plateau has been reached restricted by current technologies.

4) Aesthetics As the differentiation between the products on the market reduces, the importance of aesthetics as a buying factor increases. To improve aesthetics, various levels of solenoid integration into directional control valves exist. Although the resultant has been a move away from the original mechanical valves, the directional control valve specification itself has not varied, only interchangeability with its mechanical parentage has been sacrificed.

5) Electrical Wireways To increase the efficiency and effectiveness of wiring up time and fault finding of valve islands, directional control valves on valve islands are hard wired to a standard electrical connector. The module introduced to achieve this is an electrical wireway.

Unfortunately, similar to the early solenoids, the electrical wireway is still crude and an "add-on" to valve modules.

6) Reliability With increased competition, the costs for loss of production have increased significantly, and as a result the reliability of the directional control valves is critical.

To off set the potential reliability costs, individual directional control valves have an increased life (number of cycles), and are easier to disassemble from valve islands in case of failure.

Summarv of the Invention: An analysis of current developments in valve islands highlights the dependence of present directional control valves on the mechanical valves from which they are derived. Although control valve developments have provided workable solutions to the valve island applications, there has been a noticeable absence in deriving a system valve which exploits the unique potential of valve islands. The proposed valve targets and exploits the unique requirements of valve islands and disassociates completely the design of a system valve from that of the mechanical control valve.

This invention relates to a system valve which enables valve islands to be: 1) Compact - This is achieved in the main body by a development of the poppet principle which generates smaller movements for a given flow area requirement, and thereby greater flow to size ratios. Compact sizes are achieved in electro-pneumatic operators by the use of bimetallic strips positioned on top of the system valves.

2) Zero Sub-Base - By utilising the space within the system valve more efficiently, the supply and exhaust pressure pathways which are traditionally contained in a separate sub-base or manifold module, are incorporated into the main body whilst still retaining a competitive size. With a zero sub-base system valve, the flow path from the pathway to the main body poppet operator is significantly reduced, and with it the pressure losses are minimised. This enhances performance and increases the flow to size ratio for the valve.

3) Integrated Electrical Wireway - The space in the main body is further utilised to provide conduits for locating electrical connectors for the operator modules. This provides highly integrated electrical wireways which are protected from external elements such as water and dust, and from mechanical abuse by users.

4) Multi-Functional - The system valve provides the flexibility of changing the valve function to either a 5/2, 5/3 or 3/2 function by a change of the functional interface gasket. By restricting the change of valve function to an alteration of the interface gasket, a mixture of valve functions can be used on the same valve island.

Additionally, because the function of the system valve is determined without a change ofthe main valve module, configuration of the valve island can be undertaken at a very late stage prior to commissioning of the system.

5) Fixed Length or Modular System Configuration - The proposed valve enables either fixed length or modular valve islands to be created. Fixed length versions are created by machining the required number of functional cavities of the individual system valve into an extruded form. Modular versions are created by coupling together the required number of sectioned system valve modules to create a valve island.

Brief Descrxption of the Drawings: FIG. 1 is a cross sectional view showing an embodiment of the system valve according to the invention; FIG. 2 is a sectional view thereof depicting the poppet operator according to the invention; FIG. 3 is a sectional view thereof depicting an example of a bimetallic operator according to the invention, FIG. 4 is a plan view showing an example of the embodiment of the functional gasket according to the invention.

Detailed Description ofPreferred Embodiments: The system valve covered by the invention comprises four main modules as indicated in FIG. 1. These are, the main body 1, the operator 2, the functional gasket 3, and the port connector 4 which incorporates cylinder ports 4a and 4b.

The main body 1 incorporates two poppet operators 5 and 6, and the pathways 7, 8 and 9. FIG. 2 shows greater details of the poppet operator 5 which is similar to the other poppet operator 6 in the system valve. The poppet valve can be operated in both directions by pressurising either side ofthe piston 10 alternately with pilot pressure, against the seals 11 and 12 on it. This movement enables the valves seats 13 and 14 to create a seal against the nozzles 15 anc 16 respectively. Chambers 17 and 18 are separated by a seal 19 :'ambling the different pressures within the individual chambers to be separated. Similarly, chambers 20 and 21 are also separated by a seal 22 for the same reason.

In operation, when the pilot pressure is applied to the pilot chamber 17 and exhausted from the pilot chamber 20, then the piston will move in a direction such that the valve seat 13 seals against nozzle 15. This movement results in the chambers 18 and 8 being connected, allowing flow to take place from pathway 8 to chamber 18 (subject to the pressure in pathway 8 being greater than that in chamber 18 - otherwise the direction of flow is reversed). As the cylinder port 4a is linked with chamber 18, then the flow from chamber 18 continues to the cylinder port. A device connected to cylinder port 4a would therefore become pressurised.

If the pilot pressure is applied to the pilot chamber 20 and exhausted from pilot chamber 17, then the piston will move in a direction such that the valve seat 14 seals against nozzle 16. This movement results in the chambers 21 and 7 being connected allowing flow to take place from chamber 21 to pathway 7 (subject to the pressure in chamber 21 being greater than that in pathway 7 - otherwise the direction of flow is reversed). As cylinder port 4a is linked with the chamber 21, then the flow from the cylinder port continues to the pathway 7. A device connected to cylinder port 4a would therefore become depressurised.

Similarly, the device connected to cylinder port 4b can be pressurised and depressurised by the action of the poppet operator 6 in a manner similar to that described for poppet operator 5.

Because the poppet operators 5 and 6 are independent, the pressurising and depressurising of devices connected to cylinder ports 4a and 4b can take place independently from each other. This feature enables the valve to operate as a multi-flinctional system valve by the co-ordination of the pilot supply and exhaust pressures to poppet operators 5 and 6.

The functional determination of the system valve is achieved by a combination of the functional gasket 3, and the type of operator module 2 selected. But for a given operator module, the co-ordination of the operation of the poppet operators 5 and 6 is determined by the functional gasket 3.

FIG. 3 shows the pathways 29 and 30 which are the separate pathways for the pilot pressure supply and exhaust to and from the operator modules. This pilot pressure is separated from the operational pressure because it may need to be controlled and prepared closely. Using the functional gasket 3, the operator pilot pressure supply and exhaust pathways are connected to the operators 31, 31a, 32 and 32a in a double operator valve, or to operators 31 and 31a in a single operator valve. Operators 3 la and 32a are not shown in FIG. 3, but are in pneumatically isolated chambers of the same configuration along side operators 31 and 32 respectively.Using a functional gasket 3, which connects pilot ports 23 and 27 to the primary operator 31, and pilot ports 24 and 28 to the secondary operator 3 la, in a single operator valve, then the system valve can operate as a standard 5/2 valve pressuring and depressurising cylinder ports 4a and 4b alternately. When cylinder port 4a is pressurising, cylinder port 4b is depressurising and visa versa. Using a functional gasket 3, which connects pilot ports 23 and 28 to the primary operator 31, and pilot ports 24 and 27 to the secondary operator 3 la, in a single operator valve, then the system valve can operate as a double acting 5/2 valve pressuring and depressurising both cylinder ports simultaneously.

Using a double operator module 2 and a functional gasket 3, which connects pilot ports 23 and 27 to the primary set of operators 31 and 3 la, and the pilot ports 24 and 28 to the secondary set of operators 32 and 32a, then the system valve can operate as a standard 5/2 double operator valve with the cylinder ports 4a and 4b pressuring and depressurising alternately. This operation requiring two separate electrical signals.

By using a double operator module 2 and a functional gasket 3 which connects each ofthe pilot ports 23, 24, 27 and 28 to each ofthe operators 31, 31a, 32 and 32a, then the system valve can operate as either a 5/3 function valve or as two 3/2 function valves depending on the precise combination of the connections of the pilot ports to operators.

The operator module on the proposed system valve is mounted, but not always necessarily, directly onto the main body module 1. The interface between the operator module and the main body module is with the functional gasket 3. Two types of operators are used, either electrically operated or directly ported pneumatically operated. Both types of operators are either single or double operators.

For electrical types of operators, a single operator module comprises two bimetallic strips electrically connected in series but in two pneumatically isolated housings. The primary operator is a 3/2 normally open valve, whilst the secondary operator along side it is a 3/2 normally closed valve. Upon receipt of an electrical signal from the wireway 38a, the bimetallic strip 33 in the primary operator 31 closes the supply nozzle 34, allowing the pilot chamber(s) to which nozzle 36 is connected to exhaust through nozzle 35 to the collected exhaust pathway 29 via port 26. The nozzle 36 is connected by the functional gasket 3, to the respective pilot chamber(s) via the pilot port(s).Simultaneously, the same electrical signal operates the bimetallic strip in the secondary operator 3 la, which closes the exhaust nozzle 35a allowing the pilot pressure from the supply pathway 30, via the port 25, to pressurise the pilot chamber(s) through nozzles 34a and 36a.

Electrical types of operators with double operator modules comprise four bimetallic strips in four pneumatically isolated housings. The first two bimetallic strips which are the primary set are as described previously. Similarly, the other two bimetallic strips which are the secondary set operate simultaneously from the same electrical signal.

Their configuration similar to the primary set of operators is of a normally open and normally closed operator set.

The electrical signals to the operator module is via connectors in the electrical wireways 38a and 38b which are incorporated within the main body module 1.

Electrical wireway 38a connects the primary set of operators whilst electrical wireway 38b connects the secondary set of operators. The connecting cable from electrical connectors in each of the wireways to the operators, is incorporated in the operator cover 37.

Individual gaskets provide a means of connecting the pilot ports 25 (supply) and 26 (exhaust) to the respective supply nozzles 34, 34a, 34b and 34c and to the exhaust nozzles 35, 35a, 35b and 35c. The gasket also connects individual combinations of the pilot ports 23, 24, 27 and 28 to the respective nozzle in each of the operators 36, 36a, 36b and 36c. Each functional gasket provides a different combination of connections between the operators and the pilot ports depending on the system valve configuration required.

The specific functional gasket 3 shown in FIG. 4 is for a 5/3 function valve.

This connects the supply pilot port 25 to each of the supply nozzles 34, 34a, 34b and 34c. The functional gasket 3 also connects the exhaust nozzles 35, 35a, 35b and 35c from each operator in the operator module 2 to the exhaust pilot port 26. The gasket also connects the feed nozzles 36, 36a, 36b and 36c to the pilot ports 23, 24, 27 and 28.

The system valve can be configured into either a modular valve island or a fixed length system. In a modular valve island, the individual modules are coupled together through the coupling holes 39a, 39b, 39c and 39d, with each module being separated by an interface gasket. For this system, the port connector 4 can be either fixed length or modular but is always detachable from the main body module 1. For a fixed length system, each module is machined into the extrusion. For such a system, port connector 4 is also detachable from the main body module 1, but may not necessarily be fixed length.

Claims

I ) A system valve which includes two double poppet operated valves not linked to each other and housed in a main body module which may also incorporate the supply and exhaust pressure pathways and electrical wireways, a functional gasket with specifically designed tracking to achieve a desired valve function which interfaces the main body module with either a single or double operator module, a single or double operator module which can either be electrically operated or be operated directly by pneumatic means, a porting block with separate ports each one connected to the openings associated with each of the double poppet operated valves, characterised in that:: (a) said double poppet operated valves are capable of being operated independently of each other, and each individually controlling the supply and exhaust functions of a single corresponding cylinder port; (b) a functional gasket with specific tracking to act as an interface between a single operator module and the two double poppet operated valves in the main body module co-ordinating their operation to give a function equivalent to a 5/2 valve function with either port normally open to pressure;; (c) a functional gasket with specific tracking to act as an interface between a single operator module and the two double poppet operated valves in the main body module co-ordinating their operation so that only one of the double poppet operated valves operates in either a normally open or normally closed valve function, and the non-operating double poppet operated valve retained in either the normally open or the normally closed position; (d) a functional gasket with specific tracking to act as an interface between a double operator module and the two double poppet operated valves in the main body module co-ordinating their operation to give a function equivalent to a 5/2 valve function with either port normally open to pressure;; (e) a functional gasket with specific tracking to act as an interface between a double operator module and the two double poppet operated valves in the main body module co-ordinating their operation to give a function equivalent to a 5/3 valve function with a centre position in which the cylinder ports are either normally open to pressure or normally open to exhaust; (f) a functional gasket with specific tracking to act as an interface between a double operator module and the two double poppet operated valves in the main body module co-ordinating their operation to give a function equivalent to two independent 3/2 valve functions with their ports being independently normally open or closed to pressure;; (g) for any operator and pneumatic module combination previously described, the valve function can be determined or inter-changed between 5/2, 5/3 and 3/2 valve functions by the selection of any of the functional gaskets described in the preceding claims I (b) to 1(f).
2) A system valve as defined in claim 1, characterised in that the main body module is produced from an extrusion to produce a fixed length system, or from individual modules to produce a modular system.
3) A system valve as defined in claims 1 or 2, characterised in that the main body module incorporates the supply and exhaust pressure paths making the system a zero-sub-base system.
4) A system valve as defined in claims 1, 2 or 3, characterised in that the main body module incorporates the electrical wireways.
5) A system valve as defined in any preceding claim, characterised in that the operator modules (single or double) interfaced to the main body by a functional gasket can be electrically, or direct pneumatically operated.
6) A system valve as defined in any preceding claim, characterised in that a mixture of valve functions 5/2, 5/3 and 3/2 can be arranged on the same valve island.