Valve, in particular control or shut-off valve, for liquid or gaseous media

Abstract

Valve (11), in particular a control or shut-off valve, for liquid or gaseous media, comprising a valve housing (12) having at least one through-bore (14) connecting an inlet opening (21) to an outlet opening (16), a valve seat (17) arranged on the valve closure housing (12) and surrounding the through-bore (14), which valve seat can be closed by a valve closure member (31) arranged in a regulating chamber (22) formed in the valve housing (12) between the inlet opening (21) and the outlet opening (16), a drive (35) connectable to the valve housing (12), which drive has at least one actuating element (39) made of a shape memory alloy to control the opening and closing movement of the valve closure member (31) and actuates the valve closure member (31) to open or close the through-bore (14), and a return element (33),which counteracts a closing or opening movement of the valve closing member (31), wherein the actuating element (39) is formed from at least one wire element and can be controlled by energizing it with a control device (44), and the actuating element (39) acts between an engagement point (34) of the valve closing member (31) and an engagement point (37) on the valve housing (12) or on the housing section (19) that can be attached thereto, and the actuating element (39) is arranged in the regulating chamber (22) through which the medium flows, characterized in that - that the adjusting element (39) is surrounded by a protective sleeve (45) which extends completely along the at least one adjusting element (39), and - that the protective sleeve (45), which forms an annular gap between its inner circumferential surface and the actuating element (39) and whose length corresponds to or is shorter than the length of the non-activated actuating element (39), has at least one opening (46) which connects the annular gap to the environment outside the protective sleeve (45).

Description

[0001] The invention relates to a valve, in particular a control or shut-off valve, for liquid or gaseous media according to the preamble of claim 1.

[0002] EP 2 781 742 A1 discloses a valve, in particular a control or shut-off valve for a cooling circuit. This valve comprises a valve housing in which an inlet opening is connected to an outlet opening through a through-bore. A valve closing element opens and closes the through-bore. The valve closing element can be controlled via an actuating element made of a shape memory alloy. A return element counteracts an opening movement of the valve closing element.

[0003] WO 02 / 050460 A1 discloses a hydraulic valve comprising a housing with an inlet and an outlet. A valve seat is provided between the inlet and the outlet, which valve seat can be closed with a valve closure member. To move the valve closure member between an open position and a closed position, it is connected to a control mechanism controlled by two actuators made of a shape memory alloy. The two actuators are arranged within a housing section separated from the flowing medium and are cooled directly by the ambient air via ventilation openings.

[0004] DE 20 2012 104 460 U1 discloses a shut-off valve comprising a valve housing with a through-hole connecting an inlet and an outlet. The through-hole is surrounded by a valve seat, which opens and closes the through-hole by means of a valve closing element that can be arranged thereon. The valve closing element is actuated by a drive for controlling the opening and closing movement, wherein the drive comprises at least one actuating element made of a shape memory alloy. A return element counteracts the opening movement of the valve closing element. In this shut-off valve, the actuating element is shielded from the medium flowing between the inlet and outlet openings by a sealing element provided in the regulating chamber.

[0005] JP S61-19 368 A discloses a valve box with an inlet and an outlet for a printing ink. Within the valve box, a sealing element is arranged on a bellows, which closes the outlet. The bellows forms a space completely sealed from the printing ink in the valve box, within which an actuating element made of a shape memory alloy is provided. By shielding the valve box from the printing ink, the actuating element controls the opening and closing movement of the sealing element independently of the pressure or temperature of the printing ink.

[0006] US Pat. No. 3,835,659 A discloses an expansion valve for a refrigeration system, in which a valve closing element is arranged in a first passage, which is controlled by a wire element made of a shape memory alloy. The wire element is provided within a second passage of the expansion valve, so that the latter controls the valve closing element depending on the temperature of a coolant in the second passage.

[0007] DE 592 886 A describes a thermocouple for non-contact temperature measurement in which the two elements generating the thermoelectric force are coated with a graphite layer. The graphite layer enables high resistance to external thermal influences, making the thermocouple suitable for measuring particularly high temperatures.

[0008] WO 2012 / 106415 A1 discloses a valve with a valve housing having a through-bore connecting an inlet opening with an outlet opening. A return spring and an actuating element made of a shape memory alloy are provided within the valve housing. To open the through-bore, the actuating element is energized, causing a valve closure member to open a through-bore. This actuating element made of the shape memory alloy works against a return spring. The actuating element is connected downstream of a regulating chamber through which the medium flows.

[0009] US Pat. No. 3,613,732 A discloses a valve comprising a valve housing with an inlet opening and an outlet opening, with a regulating chamber formed therebetween. Within the regulating chamber, a valve closing element is provided, the opening movement of which is controlled by an actuator with a shape memory alloy, which works against the restoring force of a restoring element.

[0010] A linear actuator is known from DE 199 34 827 C1. This actuator comprises an elongated actuator element made of a shape memory alloy for length adjustment. This actuator element is mounted in a housing for free movement and is firmly connected to the housing at only one connection point. This housing extends parallel in the longitudinal direction to the actuator element and completely encloses the actuator element.

[0011] GB 2 106 190 A also discloses an actuator made of a shape memory alloy, which is guided within a hose. This hose serves as a housing for conveying a fluid between the actuator and the hose. The actuator is controlled by a change in the fluid's temperature.

[0012] The invention is based on the object of proposing a valve in which at least a rapid control of an opening and closing movement of the valve closing member is possible with an actuating element arranged in the regulating chamber.

[0013] This object is achieved by a valve, in particular a control or shut-off valve, according to the features of claim 1. Further advantageous embodiments and developments are specified in the further claims.

[0014] The design of the actuating element, consisting of at least one wire element made of a shape memory alloy, is surrounded by a protective sleeve that extends completely along the at least one actuating element and forms an annular gap between the inner surface and the actuating element. At least one opening is provided in the protective sleeve, connecting the annular gap to the environment outside the protective sleeve. This enables precise control of the opening and closing movement via the wire element made of the shape memory alloy. This protective sleeve also shields the wire element for controlling the opening and closing movement of the valve closure member from the flowing medium.This provides, in particular, thermal insulation of the wire element, and the activation energy when energized to the wire element made of the shape memory alloy can be specifically controlled for the desired contraction of the wire element or the closing movement of the valve closure member. Through the at least one opening in the protective sleeve, a medium in the annular gap between the actuating element and the protective sleeve can flow out through the at least one opening if the medium in the annular gap begins to boil.

[0015] According to a first embodiment, the protective sleeve is loosely placed over the wire element, forming an annular gap between the sleeve and the wire element, which is filled with the medium. This annular gap is preferably narrow, so that in the case of a non-boiling medium or a medium that does not boil in the immediate vicinity when the actuating element is activated, only a thin film of the medium can form between the wire element and the protective sleeve. This, in turn, allows for thermal insulation, as this thin film of medium forms stationary in the annular gap between the wire element and the protective sleeve. This heats up the annular gap. The thermal energy is prevented from flowing away, thereby shortening the response time for controlling the actuating travel of the valve closing element.In the case of a boiling medium, energizing the actuating element can cause the medium in the annular gap to evaporate, forming an air or vapor layer in the annular gap that displaces the liquid medium from the annular gap and, in particular, renders the annular gap liquid-free. This air or vapor layer also provides thermal insulation, which also improves the actuation and response of the actuating element. The annular gap is preferably between 0.01 mm and 0.2 mm. As soon as the actuation or energization of the actuating element ceases, the annular gap refills with medium.

[0016] A preferred embodiment provides for the sleeve to be made of an expandable plastic. Preferably, a plastic sleeve made of Teflon is provided, which not only has the expandable property but also offers low sliding friction, so that the wire element can perform a working stroke without interference.

[0017] The protective sleeve, which forms an annular gap between its inner surface and the actuating element, has at least one, preferably two, spaced-apart openings which connect the annular gap to the environment outside the protective sleeve. The provision of at least two spaced-apart openings is preferably provided when the protective sleeve corresponds to the length of the actuating element or is shorter. This makes it possible for a medium which boils in the annular gap during actuation of the actuating element to be forced out of the protective sleeve due to the vapor layer that forms, so that only a vapor layer can form between the actuating element and the protective sleeve. This accelerates the response behavior of the actuating element and thus improves ventilation or closing movements.Control movements for the valve closing element are enabled.

[0018] The protective sheath preferably surrounds the wire element at the point of engagement on the valve closure member. This has the particular advantage of preventing cooling of the wire element at the point of engagement. Temperature changes can occur in the area of the through-opening due to the flow of the medium, which can impair the working stroke of the valve closure member. However, this is prevented by the protective sheath arranged in the area of the point of engagement.

[0019] The at least one wire element and the protective sheath surrounding the wire element are preferably jointly attached to the valve closure member, in particular clamped or crimped. This enables cost-effective production.

[0020] An alternative embodiment provides that the at least one wire element is at least simply deflected at the deflection point of the valve closure member, and the protective sleeve of the wire element extends at least along the deflection point. This not only provides thermal insulation of the wire element in the region of the deflection point, particularly at the valve closure member, but also enables improved sliding friction at the deflection point itself, which in turn increases service life and improves functionality.

[0021] Advantageously, the protective sheath and the wire element are attached together at the respective contact point, particularly by crimping. This enables cost-effective production.

[0022] The protective sleeve, which extends over the entire length of the wire element, is preferably pre-stretched or attached under tension at the respective points of engagement. This has the advantage that when the wire element is subjected to a working stroke, the wire element only has to work against the actuating force of the return element and does not require additional compression of the protective sleeve to execute an opening movement of the valve closure element.

[0023] The at least one actuating element of the valve can preferably be controlled by means of a control device which controls the opening and closing movement of the valve closing member as a function of at least one controlled variable, in particular the temperature of the liquid and gaseous medium. Taking into account at least one further controlled variable enables characteristic map control of the actuating element for controlling the opening and closing position of the valve closing member. At a certain temperature of the refrigerant in the control chamber, a defined actuating travel for opening or closing the valve can be controlled with a predetermined current supply to the actuating element. If, for example, the temperature of the liquid and gaseous medium changes, a modified or adapted current supply is required for the same actuating travel.This can be determined in advance in order to determine and create a characteristic map of the actuating travel with respect to the current supply as a function of the temperature of the liquid or gaseous medium. Other parameters, such as the number of actuating elements, the cross-sections of the actuating elements, and the specific alloy selection of a shape memory alloy for such actuating elements, can also be taken into account. This enables the control system to provide a characteristic map for the opening and closing movement of the valve closure element, which, for example, represents a function of the heat loss or the thermal heating of the actuating element relative to the environment.

[0024] The invention, as well as further advantageous embodiments and developments thereof, are described and explained in more detail below with reference to the examples shown in the drawings. The features shown in the description and the drawings can be used individually or in any combination according to the invention. They show: Fig. 1 is a schematic sectional view of a first embodiment of a valve not belonging to the invention, Fig. 2 a schematic sectional view of a first alternative embodiment to Fig. 1, Fig. 3 is a schematic sectional view of a second alternative embodiment to Fig. 1, Fig. 4 a schematic sectional view of an alternative embodiment to Fig. 3 and Fig. 5 a schematic sectional view of a further alternative embodiment to Fig. 3.

[0025] In Fig. 1 shows a valve 11 which is designed, for example, as a shut-off valve. This comprises a valve housing 12 which has a through-bore 14 which opens into an outlet opening 16. At an opposite end of the through-bore, a valve seat 17 is arranged, which, for example, has a crater-shaped elevation. Furthermore, a sleeve-shaped housing section 19 is provided on the valve housing 12. This can be arranged in one piece on the valve housing 12. Alternatively, it can also be attached to the valve housing 12 by a detachable connection, such as a screw connection or a material connection. The sleeve-shaped housing section 19 has at least one inlet opening 21 through which a liquid or gaseous medium passes into a regulating chamber 22. This regulating chamber 22 is delimited by the sleeve-shaped housing section 19.

[0026] A shoulder or a fastening section 25 can be arranged on the sleeve-shaped housing section 19. This fastening section 25 can be formed by an annular or disc-shaped element, which in a two-part sleeve-shaped housing section 19 can be arranged between a first and second housing section or a sleeve section and a second cover. Alternatively, such a fastening section 25 can also be formed on one of the two sections, the sleeve section or the cover section. Alternatively, it can also be formed solely by a cross-sectional reduction in the form of a shoulder on the cover. A return element 33 is supported on this fastening section 25 and engages opposite a holding section 28 that is formed on a valve closing member 31.Alternatively, it can be provided that the return element 33 is supported on the bottom 27 of the sleeve-shaped housing section 19 instead of on the fastening section 25.

[0027] The valve closing member 31 rests against the valve seat 17 in a closed position, preferably directly, and is held in this closed position by the return element 33. This closes the valve 11. The valve closing member 31 can have a holding section 28, which can be formed integrally with the valve closing member. Advantageously, the holding section 28 extends radially outward and is arranged with a small annular gap to the wall of the sleeve-shaped housing section 19 and can be guided along this. Guide sections can preferably be formed for this purpose. The outer circumference of the holding section 28 can additionally have notches so that the medium can flow completely through the regulating chamber 22.

[0028] The valve closing member 31 is driven by a drive 35 to open and close the through-bore 14. The drive 35 comprises at least one actuating element 39, which is driven via control lines 42 by a control system (not shown in detail).

[0029] A first engagement point 34 for the at least one adjusting element 39 made of a shape memory alloy is provided on the valve closure member 31 or retaining element 28. This adjusting element 39 is preferably designed as a wire element. This extends from the engagement point 34 to an opposite engagement point 37, which is provided on the bottom 27 of the sleeve-shaped housing section 19.

[0030] According to the illustrated embodiment, the adjusting element 39 is designed as a straight wire element or rod-shaped wire element. Furthermore, it can also be a coiled wire element. Alternatively, several such wire elements can be provided, which are aligned in a circle relative to one another, for example, to form a type of rod cage.

[0031] The point of application 37 is located, for example, in the feed opening 41, at the bottom 27 of the sleeve-shaped housing section 19 or in a sealing element 43 surrounding the feed opening 41, within which the actuating element 39 is connected to control lines 42 which are connected to the control device 44 for supplying current to the actuating element 39.

[0032] The control element 39, which consists of a shape memory alloy, can be adapted depending on the respective application and the control temperature with respect to the medium.

[0033] The actuating element 39 is surrounded by a protective sleeve 45. This protective sleeve 45 extends essentially over the entire length of the actuating element 39, with the length of the protective sleeve 45 being shorter than the actuating element 39 by the amount corresponding to the maximum working stroke of the actuating element 39. This prevents the need for additional compression of the protective sleeve 45 by the actuating element 39 when opening the valve closure member 31.

[0034] According to this embodiment, the protective sleeve 45 is designed to fit tightly against the actuating element 39. For example, an inner diameter of the protective sleeve corresponds to the outer diameter of the actuating element 39. The protective sleeve 45 is preferably made of plastic. Preferably, an expandable plastic is provided. In particular, Teflon can be selected. In this embodiment, Fig. 1, it is provided that the protective sleeve 45 is arranged at a distance from the point of application 34 on the valve closing member 31 and from the point of application 37 on the base 27 on the actuating element 39.

[0035] Alternatively, the protective sleeve 45 can be designed with an inner surface that is larger than the outer circumference of the adjusting element 39, so that a small annular gap is formed between the protective sleeve 45 and the adjusting element 39. For example, the adjusting element 39 can have an outer diameter of 0.3 mm and the inner surface of the protective sleeve 45 can have a diameter of 0.4 mm. This allows the protective sleeve 45 to be easily displaced relative to the adjusting element 39.

[0036] In Fig. 2 is an alternative embodiment of the valve 11 to Fig. 1. This embodiment differs in that the protective sleeve 45 is also fastened at the point of action 34 like the actuating element 39. For example, the actuating element 39 and the protective sleeve 45 can be fastened thereto together, in particular by a common crimp. This arrangement has the advantage that the actuating element 39 is thermally insulated in the region of the point of action 34. In this region, the flow around the valve closing member 31 can cause the actuating element 39 to cool down at the point of action 34. This is prevented by this arrangement of the protective sleeve 45. Alternatively, the protective sleeve 45 can also extend to a lower point of action 37 and completely surround the actuating element 39. Both can also be fastened together at the point of action 37.

[0037] In this embodiment according to Fig. 2, it can additionally be provided that near the point of application 34 in the protective sleeve 45, at least one opening 46 is provided, which connects the regulating chamber 22 to an annular gap formed between the protective sleeve 45 and the actuating element 39. If a medium is used which begins to boil in the region of the annular gap between the actuating element 39 and the protective sleeve 45 when the actuating element 39 is energized, a faster displacement of the medium located in the annular gap is achieved, since this medium present in the annular gap can escape both at one end of the protective sleeve 45 pointing at a distance from the seal 43, and oppositely via at least one opening 46 arranged near the point of application 34.

[0038] Furthermore, the valve 11 is designed, for example, as a control valve and, in deviation from the shut-off valve in Fig. 1 on the valve closing member 31 instead of a flat closing surface, a conical closing contour 32 which extends into the through hole 14 and rests against the valve seat 17. Alternatively, the valve closing member 31 can also be designed according to Fig. 1, so that the valve 11 according to Fig. 2 is designed as a shut-off valve. This valve closing element 31 with the closing contour 32 can also be used in the valve 11 according to Fig. 1 can be used.

[0039] In Fig. 3 is an alternative embodiment to Fig. 1. This embodiment in Fig. 3 differs in that instead of the engagement point 34, a deflection point 48 is provided, so that a simple deflection of the actuating element 39 is formed. This deflection point 48 can be formed, for example, by a pin, U-shaped bracket or the like. Between the deflection point 48 and the two engagement points 37, a protective sleeve 45 is provided on each section of the actuating element 39. The protective sleeve 45 can, for example, be analogous to the Fig. 1. The length of the protective sleeves 45 is provided such that the valve closing member 31 can perform an unhindered opening movement up to the maximum opening position without the protective sleeve 45 counteracting this opening movement.

[0040] It is understood that several such single deflections can be provided on the valve closure member 31. The deflection point(s) 48 can also be provided on the base 27. It can also be provided that one or more deflection points 48 are provided on both the valve closure member 31 and the base 27, so that an actuating element 39 is deflected once or multiple times, or that several actuating elements 39 are deflected once or multiple times.

[0041] In Fig. 4 is an alternative embodiment to Fig. 3, to which reference is made. This embodiment differs in that the adjusting element 39 is surrounded by a protective sleeve 45, which also extends along the deflection point 48. This, in turn, has the advantage of providing thermal insulation of the adjusting element 39 at the deflection point 48. In addition, an improved sliding surface for the adjusting element 39 can be created at the deflection point.

[0042] In this embodiment, it can also be provided that adjacent to the deflection point 48 or in the vicinity of the deflection point 48 at least one opening is provided in the protective sleeve 45 in order to connect the regulating chamber 22 with the annular gap between the adjusting element 39 and the protective sleeve 45. Analogously, the Fig. 2 described mode of operation of the opening also applies to this embodiment.

[0043] In Fig. 5 is an alternative embodiment to Fig. 4. This embodiment is modified in that the protective sleeve 45 extends along the entire length of the actuating element 39. For example, the protective sleeve 45 is attached by its two free ends to the engagement points 37. These ends can be crimped together with the ends of the actuating element 39. This arrangement has the advantage of providing not only thermal insulation of the actuating element 39, but also electrical insulation.

[0044] At the Fig. In the embodiment shown in Figure 5, it can be provided that the protective sleeve 45 is pre-stretched or fastened under tensile stress.

[0045] If a medium flows through the valve 11 which begins to boil in the annular gap formed by the protective sleeve 45 when the actuating element 39 is activated, it is advantageously provided that at least one opening near the deflection point 48 and at least one further opening near the respective point of action 37 is provided in the protective sleeve 45 in order to enable the remaining liquid portion of the medium in the annular gap to flow out through the opening in the regulating chamber 22 when the medium in the annular gap begins to evaporate.

[0046] In all of the previously described embodiments, such additional openings 46 can be provided in the protective sleeve 45 to enable a faster outflow of the medium located in the annular gap, provided that an evaporation process of the medium in the annular gap occurs upon activation of the actuating element 39. At the same time, such openings also enable a rapid filling of the annular gap with medium after the end of an actuating movement.

[0047] It is understood that the Fig. The arrangements and configurations of the protective sleeve 45 and / or the deflection points 48 shown in Figures 2 to 5 can also be provided in reverse. In particular, the deflection point 48 can also be provided on the bottom 27 of the valve housing 12, in particular the sleeve-shaped housing section 19, instead of on the valve closing member 31. These statements apply to both one and multiple actuating elements 39.

[0048] The valves 11 according to the Fig. 3 to 5 can also be designed as control or shut-off valves.

[0049] The above-described embodiments thus have the advantage that, due to the arrangement of the protective sleeve 45, a significantly lower amount of energy is required to control the actuating movement of the valve closure member 31 than would be the case without the protective sleeve 45. By using this protective sleeve 45, the activation energy when using a liquid medium can be brought to the value of the activation energy when operating with a gaseous medium.

Claims

[1] Valve (11), in particular a control or shut-off valve, for liquid or gaseous media, comprising a valve housing (12) which has at least one through-bore (14) connecting an inlet opening (21) to an outlet opening (16), a valve seat (17) arranged on the valve closure housing (12) and surrounding the through-bore (14), which valve seat can be closed by a valve closure member (31) which is arranged in a regulating chamber (22) formed in the valve housing (12) between the inlet opening (21) and the outlet opening (16), a drive (35) connectable to the valve housing (12), which drive has at least one actuating element (39) made of a shape memory alloy to control the opening and closing movement of the valve closure member (31) and actuates the valve closure member (31) to open or close the through-bore (14), and a return element (33),which counteracts a closing or opening movement of the valve closing member (31), wherein the actuating element (39) is formed from at least one wire element and can be controlled by energizing it with a control device (44), and the actuating element (39) acts between an engagement point (34) of the valve closing member (31) and an engagement point (37) on the valve housing (12) or on the housing section (19) that can be attached thereto, and the actuating element (39) is arranged in the regulating chamber (22) through which the medium flows, characterized by , - that the adjusting element (39) is surrounded by a protective sleeve (45) which extends completely along the at least one adjusting element (39), and - that the protective sleeve (45), which forms an annular gap between its inner circumferential surface and the actuating element (39) and whose length corresponds to or is shorter than the length of the non-activated actuating element (39), has at least one opening (46) which connects the annular gap to the environment outside the protective sleeve (45). [2] Valve (11) according to claim 1, characterized by that the protective sleeve (45) is loosely placed over the adjusting element (39) and a small annular gap is formed between the protective sleeve (45) and the adjusting element (39), which gap is preferably between 0.01 mm and 0.2 mm. [3] Valve (11) according to claim 1, characterized by that the protective sleeve (45) is made of a plastic, in particular stretchable plastic, preferably Teflon. [4] Valve (11) according to claim 1, characterized by that the protective sleeve (45) surrounds the actuating element (49) at the point of action (34) on the valve closing member (31). [5] Valve (11) according to claim 1, characterized by that the protective sleeve (45) and the adjusting element (39) are fastened together, in particular clamped or crimped, to the point of application (34) of the valve closing member (31). [6] Valve (11) according to claim 1, characterized by that the at least one adjusting element (39) is at least simply deflected at one or more deflection points (48) on the valve closing member (31) or on the valve housing (12) and the protective sleeve (45) of the at least one adjusting element (39) extends at least along the deflection point(s) (48). [7] Valve (11) according to claim 1, characterized by that the at least one adjusting element (39) and the protective sleeve (45) surrounding the adjusting element (39) are jointly fastened, in particular crimped, at the respective point of application (34, 37). [8] Valve (11) according to claim 1, characterized bythat the protective sleeve (45), which extends over the entire length of the adjusting element (39), is pre-stretched or is fastened under tensile stress to the points of application (34, 37). [9] Valve (11) according to one of the preceding claims, characterized by that the actuating element (39) can be controlled by a control device (44) which controls the opening and closing movement of the valve closing member (31) as a function of at least one controlled variable, in particular the temperature of the liquid or gaseous medium.

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