WO2014090268A1

WO2014090268A1 - Valve arrangement

Info

Publication number: WO2014090268A1
Application number: PCT/EP2012/074880
Authority: WO
Inventors: Arne TRANGÄRD; Jeroen Derkx; Mohammadali HONARPARDAZ
Original assignee: Abb Technology Ltd
Priority date: 2012-12-10
Filing date: 2012-12-10
Publication date: 2014-06-19

Abstract

There is presented a valve arrangement (1a, 1b, 1c, 1d) for enabling a flow of a fluid to controllably pass through a valve. A chamber (3a) extends in a longitudinal direction from a first end (4a) to a second end (5a). A valve (2a) is arranged in the chamber at the first end. A closure element (6a) arranged in the chamber between the valve and the second end. A resilient elongated member (7a) placed in the chamber and arranged in said longitudinal direction. An end of the resilient elongated member is arranged at the closure element. The valve comprises a valve seat (8a) arranged to receive the closure element. The closure element is arranged to be movable in relation to the valve seat, thereby enabling a flow of a fluid to controllably pass through the valve. The resilient elongated member is bendable in a direction perpendicular to said longitudinal direction, the resilient elongated member thereby being arranged to move the closure element in relation to the valve seat. There is also presented a valve system comprising at least two such valve arrangements.

Description

VALVE ARRANGEMENT

TECHNICAL FIELD

Embodiments presented herein relate to a valve arrangement, and

particularly to a valve arrangement for enabling a flow of a fluid to

controllably pass through a valve.

BACKGROUND

A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. In an open valve, fluid flows in a direction from higher pressure to lower pressure.

The simplest valve is simply a freely hinged flap which drops to obstruct the fluid flow in one direction, but is pushed open by flow in the opposite direction. This is called a check valve, as it prevents or "checks" the flow in one direction. Valves have many uses, including controlling water for Irrigation, industrial uses for controlling processes, residential uses such as on/off and pressure control to dish and clothes washers and taps in the home. Even aerosols have a tiny valve built in. Valves are also used in the military and transport applications. Valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure, temperature, or flow. These changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or boilers. More complex control systems using valves requiring automatic control based on an external input (i.e., regulating flow through a pipe to a changing set point) require an actuator. An actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements. In general terms, positioners are used to control the opening or closing of the actuator based on electric, or pneumatic signals. Valves to regulate gas flows for positioners are often of a poppet valve design, balanced with membranes, resulting in good performance at high cost. A poppet valve (also

called mushroom valve) is a valve typically used to control the timing and quantity of a fluid flow into an engine. It consists of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide. In most applications a pressure differential helps to seal the valve and in some applications also open it.

Spool valves provide a cost effective solution however at less performance and high leakage losses.

EP o no 289 Bi discloses an equalizing valve having a bore to which a first line and, on both sides of the latter at a mutual distance, a second and third line are connected. In the bore, on both sides of the first line, a valve is provided which allows and prevents the flow of a pressure medium from the second and third lines to the first line in each case. These valves have closure elements coming into abutment against valve seats at the end of the second and third lines and which can bear alternately against a spacer slidably arranged in the valve bore. The spacer has a cylindrical portion and is provided in the region of its end faces with at least three parts extending radially outwards from the cylindrical portion for aligning the spacer in the valve bore. Further, the closure elements can each be loaded by means of a spring towards the valve seats and the radial parts are in the form of vanes with parallel side faces and/or of radial pins. Cutaways are worked into the top edges of the vanes in the region of the end faces of the spacer.

Alternatively or additionally the end faces of the cylindrical portion are of convex form. If the end faces are of non-convex form the radial pins are arranged at a distance from the end faces of the cylindrical portion. However, there is still a need for an improved valve arrangement. SUMMARY

An object of embodiments herein is to provide improved valve arrangement.

According to a first aspect there is presented a valve arrangement for enabling a flow of a fluid to controllably pass through a valve. The valve arrangement comprises a chamber extending in a longitudinal direction from a first end to a second end. The valve arrangement comprises a valve arranged in the chamber at the first end. The valve arrangement comprises a closure element arranged in the chamber between the valve and the second end. The valve arrangement comprises a resilient elongated member placed in the chamber and arranged in said longitudinal direction. An end of the resilient elongated member is arranged at the closure element. The valve comprises a valve seat arranged to receive the closure element. The closure element is arranged to be movable in relation to the valve seat, thereby enabling a flow of a fluid to controllably pass through the valve. The resilient elongated member is bendable in a direction perpendicular to said longitudinal direction, the resilient elongated member thereby being arranged to move the closure element in relation to the valve seat.

Advantageously the valve arrangement has a limited number of parts whilst still having good sealing properties. Advantageously the valve arrangement has better tightness and

controllability than a valve arrangement with spool valves.

Advantageously the valve arrangement has a lower cost compared to a valve arrangement with poppet valves

Furthermore, experiments indicate that controllability of the valve arrangement for small flow rates is better that the poppet valve based valve arrangement. This would enhance the controllability of small volume actuators, for example when used in a digital positioner system. According to a second aspect there is presented a valve system. The valve system comprises at least two valve arrangements according to the first aspect.

It is to be noted that any feature of the first aspect may be applied to the second aspect, wherever appropriate. Likewise, any advantage of the first aspect may equally apply to the second aspect, respectively, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings. Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to the accompanying drawings, in which: Figs 1 and 2 are schematic cross-section views of valve arrangements according to embodiments; and

Fig 3 is a schematic cross-section view of a valve system according to an embodiment.

DETAILED DESCRIPTION

The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.

The embodiments disclosed herein relate to enabling a flow of a fluid to controllably pass through a valve. In order to enable the flow of a fluid to controllably pass through a valve there is according to a first aspect provided a valve arrangement. There is also provided valve system comprising at least two valve arrangements according to the first aspect.

Fig l is a schematic exploded view of a valve arrangement la according to an embodiment. The valve arrangement la enables a flow of a fluid to

controllably pass through a valve. The valve arrangement la comprises a chamber 3a for accommodating a fluid. The chamber 3a extends in a longitudinal direction X from a first end 4a to a second end 5a. The fluid may enter the chamber 3a through a valve 2a. The valve 2a is arranged in the chamber 3a at the first end 4a. The valve 2a comprises a valve seat 8a.

According to an embodiment the valve seat 8a is made from an elastic material. According to one embodiment the valve seat 8a is provided with an O-ring (not shown). The fluid is prevented from escaping from the chamber 3a by means of a closure element 6a. The closure element 6a is arranged in the chamber 3a between the valve 2a and the second end 5a.

In general terms, the elements establishing the valve function are the closure element 6a and the valve seat 8a. The valve seat 8a is arranged to receive the closure element 6a. The valve seat 8a may have shape so as to enable a tight fit with the closure element 6a once the closure element 6a is placed in the valve seat 8a. For example, if the closure element 6a has a spherical shape (such as a ball) the valve seat 8a may have a conical shape so as to receive the closure element 6a. The closure element 6a will thus seat in the valve seat 8a such that the closure element 6a when completely placed in the valve seat 8a causes the opening in to the chamber 3a at the first end 4a to be closed. The closure element 6a is actuated by a resilient elongated member 7a. The resilient elongated member 7a is placed in the chamber 3a and arranged in the above defined longitudinal direction X. In particular, the resilient elongated member 7a is bendable in a direction Y, the direction Y being perpendicular to the above defined longitudinal direction X. The resilient elongated member 7a is thereby arranged to move the closure element 6a in relation to the valve seat 8a.

According to an embodiment the resilient elongated member 7a and the closure element 6a is provided as one unitary structure. That is, the resilient elongated member 7a and the closure element 6a may be manufactured from one and the same material and in one single manufacturing process.

Alternatively the resilient elongated member 7a may be coupled to the closure element 6a after manufacturing. For example the resilient elongated member 7a may be coupled to the closure element 6a by means of an adhesive material or by welding. According to an embodiment the resilient elongated member 7a is a leaf spring. According to an embodiment the closure element 6a is a ball. According to an embodiment the closure element 6a is elastic. As the skilled person understands the different embodiments related to the resilient elongated member 7a and the closure element 6a may be readily combined. For example, a resilient elongated member 7a embodied as a leaf spring may form a unitary structure with a closure element 6a embodied as a ball, where the ball may or may not be elastic.

The closure element 6a is arranged to be movable in relation to the valve seat 8a. The closure element 6a is thereby arranged to enable a flow of a fluid to controllably pass through the valve 2a. The valve 2a is thereby enabled to close a flow completely, open the channel completely, but also regulate the flow by assuming an intermediate position. That is, in a closed position the closure element 6a prevents the flow of the fluid from passing through the valve 2a. The resilient elongated member 7a is arranged to be relaxed or at most a first amount of partly loaded in the closed position. In an intermediate position the closure element 6a allows the flow of the fluid to be

regulated/controlled. The resilient elongated member 7a is arranged to be a second amount of partly loaded (the second amount being higher than the first amount) in the intermediate position. In an open position the closure element 6a allows the flow of the pressure medium to pass through the valve 2a. The resilient elongated member 7a is arranged to be fully loaded, or at least a third amount of partly loaded (the third amount being higher than the second amount) in the open position.

The valve 2a can therefore be used in control situations like, for example, electro-pneumatic positioners where an electric signal is used to control a pneumatic system that in its turn acts on a pneumatic actuator that actuates an actuated element (for example a large valve in process industry).

According to an embodiment the valve arrangement la further comprises a movable actuation element 9a. The movable actuation element 9a is arranged to act on the resilient elongated member 7a. In turn, the resilient elongated member 7a is thereby arranged to move the closure element 6a. The actuation element 9a is according to an embodiment arranged to be movable in the above direction Y, the direction Y being perpendicular to the above defined longitudinal direction X. In general terms the actuation element 9a may be movable in a direction which is substantially parallel to the above defined direction Y. The term substantially should herein be associated with a deviation of at most 20 degrees, preferably at most 15 degrees, even more preferably at most 10 degrees from being substantially parallel to the above defined direction Y.

In general terms the resilient elongated member 7a comprises two ends, schematically denoted by reference numerals 10a and 11a. According to the embodiment illustrated in Fig 1 one end 10a is arranged at the closure element 6a and the other end 11a is arranged at the second end 5a of the chamber 3a. According to the embodiment illustrated in Fig 1 the second end 5a of the chamber 3a is closed.

According to the embodiment of the valve arrangement lb illustrated in Fig 2 one end 10a of the resilient elongated member 7a is arranged at a first closure element 6a and the other end na is arranged at a second closure element 6b. In general terms, the valve arrangement lb illustrated in Fig 2 is similar to the valve arrangement la illustrated in Fig l. In general terms the valve arrangement lb comprises two of the valve arrangements la illustrated in Fig l, except that each resilient elongated member 7a, 7b of the valve

arrangement lb at respective second ends 11a, 11b are arranged at respective closure elements 6b, 6d. Thus, according to an embodiment the valve arrangement lb comprises two closure elements 6a, 6b arranged at opposite ends 10a, 11a of the resilient elongated member 7a. In more detail, the valve arrangement lb comprises a first chamber 3a and a second chamber 3b. The valve arrangement lb further comprises a first valve 2a and a second valve 2b. The first valve 2a comprises a first valve seat 8a and the second valve 2b comprises a second valve seat 8b. Further, the valve arrangement lb comprises a first closure element 6a, a second closure element 6b, a third closure element 6c and a fourth closure element 6d. The valve arrangement ib further comprises a first resilient elongated member 7a and a second resilient elongated member 7b. The first closure element 6a is arranged at one end 10a of the first resilient elongated member 7a; the second closure element 6b is arranged at the other end 11a of the first resilient elongated member 7a; the third closure element 6c is arranged at one end 10b of the second resilient elongated member 7b; and the fourth closure element 6d is arranged at the other end 11b of the second resilient elongated member 7b. Finally, the valve arrangement ib comprises a first movable actuation element 9a and a second movable actuation element 9b. Each one of the first 9a and second 9b movable actuation elements is arranged to act on one resilient elongated member 7a, 7b so as to move a respective closure element 6a, 6c with respect to its valve seat 8a, 8b. According to the embodiment of the valve arrangement ib illustrated in Fig 2 the movable actuation elements 9a, 9b are arranged with respect to the resilient elongated member 7a, 7b such that movement of the movable actuation elements 9a, 9b in the positive Y direction causes the first resilient elongated member 7a to move the first closure element 6a from its valve seat 8a. This movement also causes the contact to be lost between actuation element 9b and the second resilient elongated member 7b, the actuation element 9b thus leaving the second resilient elongated member 7b untouched and the third closure element 6c placed in the valve seat 8b such that the valve 2b is sealed.

Fig 3 is a schematic exploded view of a valve system 12 according to an embodiment. The valve system 12 comprises two valve arrangements lc and id. In comparison to the valve arrangements la and lb, each one of the valve arrangements lc and id illustrated in Fig 3 comprises a further valve and a further valve seat arranged at the second end of each chamber. The valve system 12 comprises a first valve arrangement lc and a second valve arrangement id. In particular, the valve system 12 may comprise at least two valve arrangements la, lb, lc, id.

In the illustrated embodiment of Fig 3 there is a further closure element / valve seat combination placed at a valve opposite the valve at the first end of each chamber. That is, according to an embodiment each valve arrangement lc, id comprises two valves (2a, 2b and 2c, 2d) located at opposite ends (4a, 5a and4b, 5b) of each chamber 3a, 3b. Each one of the valves comprises one valve seat 8a, 8b, 8c, 8d. Each one of the closure elements 6a, 6b, 6c, 6d may then be arranged to be movable in relation to a separate valve seat 8a, 8b, 8c, 8d.

According to the embodiment illustrated in Fig 3, the closure elements 6a, 6b, 6c, 6d are arranged at ends 10a, 11a, 10b, 11b of the resilient elongated members 7a, 7b in such a way that a pre-load is created on the closure elements 6a, 6b, 6c, 6d that will shut ports 4a, 5a, 4b, 5b tight. To actuate the valves 2a, 2b, 2c, 2d a joining element 13 is arranged to be displaced axially (i.e., in a direction Y perpendicular to the longitudinal axis of the chambers 3a, 3b). This will put (via the actuation elements 9a, 9b) a load on the resilient elongated members 7a, 7b that will cause a bending of the resilient elongated members 7a, 7b and hence result in a deflection of the resilient elongated members 7a, 7b. The deflection will result in a reduction of the distance between the closure elements 6a, 6b, 6c, 6d. The closure elements 6a, 6b, 6c, 6d will thereby be moved along the surface of the valve seats 6a, 6b, 6c, 6d, thereby opening the valves 2a, 2b, 2c, 2d. The joining element 13 is arranged on a guide pin 14. In turn, the guide pin 14 is attached to a brace 15. Alternatively the joining element may be preloaded with a spring (not shown). Thus, movement of the brace will impact the state (opening and closing) of the valves 2a, 2b, 2c, 2d. That is, according to embodiments each of the valve arrangements comprises at least one movable actuation element 9a, 9b arranged to act on a corresponding resilient elongated member 7a, 7b. All movable actuation elements 9a, 9b may then be joined by a joining element 13. All movable actuation elements 9a, 9b are thereby arranged to be actuated by movement of the joining element 13. As the skilled person understands, the illustrated embodiment of the joining element 13, guide pin 14 and brace 15 are just one of many possible ways to cause deflection of the resilient elongated member 7a, 7b. The actuation of the resilient elongated member 7a, 7b may be achieved in many different ways. For example the guide pin 14, the brace 15 and the joining element 13 may be integrated into one unitary structure.

Exemplary operation of the disclosed valve arrangements la, lb, IC, id will now be disclosed with reference to the valve system 12 of Fig 3. In the below ports 4b and 5b will be termed input ports and ports 4a and 5a will be termed output ports. Firstly, the two input ports 4b and 5b are supplied with a supply pressure (for example 10 bar). The output ports 4a and 5a are supplied with atmospheric pressure. Port 16 (barely visible behind joining element 13 at actuation element 9a) is connected to the output, for example a volume of which the pressure is to be controlled. When displacing the joining element 13 downwards (i.e. in negative Y direction) the lower elongated member 7b will be deformed and the input ports 4b and 5b open, thereby increasing the pressure/flow in the controlled volume enclosed by chambers 3a and 3b. Displacing the joining element 13 upwards (i.e. in positive Y direction) will, in the same manner, lead to a venting of the controlled volume. In the neutral/middle position all valves 2a, 2b, 2c, 2d remain closed and the controlled volume is unaffected. As the skilled person understands the valve arrangements ic, id of Fig 3 may be interchanged by two valve arrangements la of Fig 1 or one valve

arrangement lb of Fig 2, mutatis mutandis. Hence, the valve system 12 may alternatively comprise at least two valve arrangements la as illustrated in Fig 1 or at least one valve arrangement lb as illustrated in Fig 2.

The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims. For example, any of the disclosed valve arrangements and/or valve system may be used in any applications where a simple valve design and good flow controllability are needed. It is noted that any of the disclosed valve arrangements la, lb, ic, id and/or valve system 12 enables a controllable opening behaviour, making it possible to regulate small flow volumes, whilst, at the larger end of its stroke, still allowing a large flow capability. Any of the disclosed valve arrangements la, lb, ic, id and/or valve system 12 may be applied in digital positioners, such as models TZIDC and EDP300 from ABB Ltd. Also, any of the disclosed valve arrangements la, lb, ic, id and/or valve system 12 may be applied in mechanical positioners, such as in the AV-series from ABB Ltd. Any of the disclosed valve arrangements la, lb, ic, id and/or valve system 12 may further be applied in other applications where a fluid flow is to be regulated. One example is proportional pneumatic valves.

Further examples include, but are not limited to (electro-pneumatic) positioners, controlling valves in chemical plants, controlling fluid valves in power plants, controlling wastewater flow, as well as valves for controlling other elements that need actuation.

Claims

1. A valve arrangement (la, lb, IC, id) for enabling a flow of a fluid to controllably pass through a valve, the valve arrangement comprising:

a chamber (3a) extending in a longitudinal direction (X) from a first end (4a) to a second end (5a);

a valve (2a) arranged in the chamber (3a) at the first end (4a);

a closure element (6a) arranged in the chamber (3a) between the valve (2a) and the second end (5a); and

a resilient elongated member (7a) placed in the chamber (3a) and arranged in said longitudinal direction (X), wherein an end (10a) of the resilient elongated member (7a) is arranged at the closure element (6a) ; the valve comprising a valve seat (8a) arranged to receive the closure element (6a);

wherein the closure element (6a) is arranged to be movable in relation to the valve seat (8a), thereby enabling a flow of a fluid to controllably pass through the valve (2a); and

wherein the resilient elongated member (7a) is bendable in a direction (Y) perpendicular to said longitudinal direction (X), the resilient elongated member (7a) thereby being arranged to move the closure element (6a) in relation to the valve seat (8a).

2. The valve arrangement (la, lb, ic, id) according to claim 1, further comprising a movable actuation element (9a), the movable actuation element (9a) being arranged to act on the resilient elongated member (7a) so as to move the closure element (6a).

3. The valve arrangement (la, lb, ic, id) according to claim 2, wherein the actuation element (9a) is arranged to be movable in said direction (Y) perpendicular to said longitudinal direction (X).

4. The valve arrangement (la, lb, ic, id) according to any one of the preceding claims, wherein the resilient elongated member (7a) comprises two ends (10a, 11a), one (10a) of which is arranged at the closure element (6a), and the other (11a) of which is arranged at the second end (5a) of the chamber.

5. The valve arrangement (la, lb, IC, id) according to any one of the preceding claims, wherein the valve arrangement comprises two closure elements (6a, 6b) arranged at opposite ends (10a, 11a) of the resilient elongated member (7a).

6. The valve arrangement (la, lb, ic, id) according to any one of the preceding claims, wherein the valve arrangement comprises two valves (2a, 2b) located at opposite ends (4a, 5a) of the chamber (3a), each one of the two valves comprising one valve seat (8a, 8b).

7. The valve arrangement (la, lb, ic, id) according to claim 6 when dependent on claim 5, wherein each one of the two closure elements (6a, 6b) is arranged to be movable in relation to a separate valve seat (8a, 8b).

8. The valve arrangement (la, lb, ic, id) according to any one of claims 1 to 5, wherein the second end (5a) of the chamber (3a) is closed.

9. The valve arrangement (la, lb, ic, id) according to any one of the preceding claims, wherein the resilient elongated member (7a) and the closure element (6a) is provided as one unitary structure.

10. The valve arrangement (la, lb, ic, id) according to any one of the preceding claims, wherein the resilient elongated member (7a) is a leaf spring.

11. The valve arrangement (la, lb, ic, id) according to any one of the preceding claims, wherein the closure element (6a) is a ball.

12. The valve arrangement (la, lb, ic, id) according to any one of the preceding claims, wherein the closure element (6a) is elastic.

13. The valve arrangement (la, lb, ic, id) according to any one of the preceding claims, wherein the valve seat (8a) is made of an elastic material.

14. A valve system (12) comprising at least two valve arrangements (la, lb, lc, id) according to any one of the preceding claims.

15. The valve system (12) according to claim 14, wherein each of the at least two valve arrangements (la, lb, lc, id) comprises at least one movable actuation element (9a, 9b) arranged to act on a corresponding resilient elongated member (7a, 7b), and wherein all movable actuation elements (9a, 9b) are joined by a joining element (13), said all movable actuation elements (9a, 9b) thereby being arranged to be actuated by movement of the joining element (13).