Valve and method

Abstract

To provide a thermally activatable valve.SOLUTION: A valve 20 includes a valve body 22 that defines a flow passage, a valve seat 28 in the flow passage, a valve element 30 that is initially in a closed position with respect to the valve seat to block the flow through the flow passage, a bonding material 32 that secures the valve element to the closed position, and at least one heater 34 adjacent to the valve seat and operable to heat the bonding material at least to a temperature at which the bonding material releases the valve element to move to an open position with respect to the valve seat to open the flow through the flow passage.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a thermally actuated valve.

Background Art

[0002] Pilot valves are used in fluid supply systems such as launchers, rockets, spacecraft, and space probes. A pilot valve is a disposable valve that uses an electrical signal to ignite an explosive charge. This charge generates high-pressure gas, which opens the valve (in the case of a normally closed structure) or closes the valve (in the case of a normally open structure). Pilot valves have a fast response time and a low leakage rate, but often require specially trained personnel for safe handling, access to the pilot valve during final assembly (which limits design flexibility), and strict regulatory compliance.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Accordingly, an object of the present invention is to provide an improved valve such that the above-mentioned disadvantages are reduced.

Means for Solving the Problems

[0004] A valve according to an example of the present disclosure includes a valve body defining a flow path, a valve seat within the flow path, and a valve element initially in a closed position relative to the valve seat to block flow through the flow path. A bonding material fixes the valve element in the closed position. At least one heater is adjacent to the valve seat and is operable to heat the bonding material to at least a temperature at which the bonding material releases the valve element and moves it to an open position relative to the valve seat to open the flow through the flow path.

[0005] In a further embodiment of any of the foregoing embodiments, the bonding material is an alloy including tin and indium, and the temperature is the melting point of the alloy.

[0006] In a further embodiment of any of the foregoing embodiments, the bonding material is an alloy having a composition of a first weight percent of tin and a second weight percent of indium, and the second weight percent is greater than the first weight percent.

[0007] In a further embodiment of any of the foregoing embodiments, at least one heater surrounds the valve seat.

[0008] In a further embodiment of any of the foregoing embodiments, at least one heater is disposed outside the valve body such that the valve seat defines a valve seat surface and the valve seat surface intersects at least one heater.

[0009] In a further embodiment of any of the foregoing embodiments, the valve element holds at least one heater.

[0010] In a further embodiment of any of the foregoing embodiments, at least one heater includes a first heater outside the valve body and a second heater inside the valve body.

[0011] In a further embodiment of any of the foregoing embodiments, at least one heater includes first and second heaters outside the valve body.

[0012] A further embodiment of any of the foregoing embodiments includes a diamond-containing heat conduction element between at least one heater and the valve seat.

[0013] A method according to an example of the present disclosure includes providing a valve including a valve body defining a flow path, a valve seat within the flow path, a valve element initially in a closed position relative to the valve seat to block flow through the flow path, an adhesive fixing the valve element in the closed position, and at least one heater adjacent to the valve seat. Operating the at least one heater to heat the adhesive to at least a temperature at which the adhesive releases the valve element and moves the valve element to an open position relative to the valve seat to open the flow through the flow path.

[0014] In a further embodiment of any of the foregoing embodiments, the adhesive is an alloy including tin and indium, and the temperature is the melting point of the alloy.

[0015] A further embodiment of any of the foregoing embodiments includes conducting heat from the at least one heater to the adhesive via a diamond-containing heat conducting element.

[0016] In a further embodiment of any of the foregoing embodiments, the at least one heater includes a first heater outside the valve body and a second heater inside the valve body.

[0017] In a further embodiment of any of the foregoing embodiments, operating the at least one heater includes operating only one of the first heater or the second heater.

[0018] The present disclosure may include any one or more of the individual features disclosed above and / or below, alone or in any combination thereof.

[0019] Various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings accompanying the detailed description are briefly described as follows.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

DETAILED DESCRIPTION OF THE INVENTION

[0021] In the present disclosure, where appropriate, like reference numerals indicate like elements, and reference numerals with 100 or multiples thereof indicate modified elements that include the same features and advantages as the corresponding elements. The terms "first" and "second" as used herein are for distinguishing that there are two structurally different components or features. Further, the terms "first" and "second" are interchangeable, and the first component or feature can alternatively be referred to as the second component or feature, and vice versa.

[0022] FIG. 1 shows a cross-sectional view of a thermally activatable valve 20. As can be understood, the valve 20 can be implemented in place of a pilot valve in a spacecraft, rocket, space probe, or other system where a pilot valve is used. The valve 20 here is thermally actuated and does not use pyrotechnic charges, so it can also be considered a "pyroless" valve.

[0023] Valve 20 includes a valve body 22 that defines a flow path 24 from an inlet 26a to an outlet 26b. For example, the valve body 22 is formed of a lightweight and high-strength titanium alloy, but can be replaced with other alloys as long as the performance and durability requirements for the end use are met. The valve body 22 also defines a valve seat 28 within the flow path 24, and there is a valve element 30 adjacent to the valve seat 28. The valve seat 28 is not in contact with the valve element 30 as described later, but is a "seat" in the sense that it seals with the valve element 30 to block the flow through the flow path 24. The valve element 30 is formed of an alloy such as a copper-based alloy, but is not limited thereto. When the valve 20 is used for a liquid, one or more seals (e.g., O-rings) may be provided around the valve element 30 to block leakage.

[0024] As shown in the figure, the valve element 30 is initially in a closed position (normally closed position) with respect to the valve seat 28, blocking the flow through the flow path 24 from the inlet 26a to the outlet 26b. The "closed position" is the initial position of the valve element 30 where the flow through the flow path 24 is completely or almost completely blocked, while the "open position" is the position where the valve element 30 is moved from the closed position to allow the flow through the flow path 24. In the example shown, the valve element 30 is a piston that can move within the valve body 22 to the open position when the valve 20 is actuated (Figure 2).

[0025] The valve 20 further includes a bonding material 32 that fixes the valve element 30 to the valve seat 28 in the closed position. That is, the bonding material 32 "fixes" the valve element 30 in a predetermined position with respect to the valve seat 28. In that regard, the bonding material 32 has at least sufficient strength to hold the valve element 30 in the closed position against the pressure of the upstream fluid held by the valve 20. For example, the bonding material 32 is in the form of a continuous layer metallurgically bonded to both the valve element 30 and the valve seat 28 (valve body 22). One or more plating layers such as nickel and / or silver plating may be used to strengthen the bond.

[0026] The bonding material 32 also provides a seal between the valve element 30 and the valve seat 28 and substantially prevents fluid from flowing through the flow path 24. As an example, the bonding material 32 is an alloy containing tin and indium. For example, the alloy has a composition of a first weight percentage of tin and a second weight percentage of indium, and the second weight percentage is greater than the first weight percentage. One useful composition includes about 52% indium and about 48% tin, based on the total weight of the bonding material 32. Indium has a lower melting point (118 °C) compared to tin. The melting point of the bonding material 32 is determined by the In:Sn ratio, and thus the ratio can be selected to achieve the desired melting point of the bonding material 32. If a higher temperature is desired, another type of solder material may be used. Further, if a stronger bond is desired, the surface area covered by the bonding material 32 can be increased.

[0027] At least one heater 34 is disposed adjacent to the valve seat 28. As used herein, "heater" refers to a heating element and not to electronic devices or other components that may be used with the heating element. The heater 34 is operable to heat the bonding material 32 to at least the temperature at which the bonding material 32 releases the valve element 30. In this regard, the heater 34 communicates with one or more processors configured to operate the heater 34 in response to the demand for fluid downstream. When released, under the pressure upstream of the fluid, the valve element 30 moves to the open position, allowing flow through the flow path 24.

[0028] The alloy of the bonding material 32 has a relatively low melting point (compared to the alloys of the valve body 22 and the valve element 30). When the heater 34 operates, it rapidly raises the temperature of the bonding material 32 to release the valve element 30. The temperature at which the bonding material is heated for release is its melting point, or a temperature near the melting point at which the bonding material 32 softens and loses the strength to fix the valve element 30. The composition of the bonding material 32 can be changed by varying the In:Sn ratio or including other elements to adjust the melting point to a desired level. When the bonding material 32 softens and melts, it loses strength and the ability to fix the valve element 30 against the head pressure of the upstream fluid blocked by the valve 20. Therefore, due to the pressure, the valve element 30 moves to the open position shown in FIG. 2, and the fluid flows through the flow path 24 to the outlet 26b.

[0029] In the illustrated example, the heater 34 is a heating coil such as a nichrome resistance heating wire and surrounds the valve body 22 at the position of the valve seat 28. For example, the valve seat 28 defines a valve seat plane P1, and the heater 34 is disposed outside the valve body 22 such that the valve seat plane P1 intersects the heater 34. For example, the plane P1 is a plane having the axial surface of the valve seat 28. That is, the heater 34 is disposed immediately outside the valve seat 28 to minimize the heat transfer distance from the heater 34 to the bonding material 32. Other types of heaters, such as a toroidal heater or a pattern coil, which are not limited to these, may alternatively be used to surround the valve seat 28. By surrounding the valve seat 28, the heater 34 can uniformly heat the bonding material 32 over the entire circumference of the valve seat 28 and uniformly release the valve element 30.

[0030] In the illustrated example, valve 20 also includes a second heater 36 held by valve element 30. For example, valve element 30 is hollow and defines an internal cavity 30a in which the second heater 36 is disposed. The second heater 36 can include an electrical connection via a plug or port 38 provided behind the valve element 30. Thus, valve 20 includes one heater 34 disposed outside the valve body 22 and another heater 36 disposed inside the valve body 22. Heaters 34 / 36 may operate in concert to heat the bonding material 32 simultaneously, or one of heaters 34 / 36 may be used as a “redundant” heater in case the other heater becomes inoperable. In yet another example shown in FIG. 3, the second heater 36, similar to the first heater 34, is not held within the valve element 30 but is disposed outside the valve body 22, but immediately outside the valve element 30.

[0031] In a further example, to facilitate rapid heating of the bonding material 32, valve 20 further includes a diamond-containing thermal conduction element 40 between the heater 34 and / or 36 and the valve seat 28. Diamond has excellent thermal conductivity and thus facilitates rapid heat transfer from the heater 34 / 36 to the bonding material 32. For example, the diamond-containing thermal conduction element 40 is a layer including diamond particles dispersed in a matrix such as a cermet or a polymer (e.g., epoxy) matrix.

[0032] Since valve 20 can be started without using an explosive charge, special handling is not required, there is no need to access the valve during final assembly, and compliance with explosive regulations is not required. Further, since heaters 34 / 36 rapidly increase the temperature of the bonding material 32, a fast response time comparable to that of a pilot valve is possible.

[0033] Related methods of using valve 20 include, as described above, providing valve 20. Providing valve 20 includes providing valve 20 as a pre-manufactured component within a fluid supply system, or manufacturing valve 20 from its sub-components for providing to a fluid system. Once in the system, the method further includes operating heater 34 and / or 36 to heat bonding material 32 to at least a temperature at which the bonding material 32 releases valve element 30 and moves it to an open position relative to valve seat 28, thereby opening the flow through flow path 24. The response time of valve 20 can be reduced by causing heat from heater 34 and / or 36 to be conducted to bonding material 32 via diamond-containing heat conducting element 40. In yet another example, one of heaters 34 or 36 is a "primary" heater and the other of heaters 36 or 34 is a "secondary" (redundant) heater in case the primary heater becomes inoperative. In this regard, an example of operation of valve 20 includes operating only one of heaters 34 or 36 at a time.

[0034] Although combinations of features are shown in the illustrated examples, it is not necessary to combine all of them to realize the advantages of the various embodiments of the present disclosure. In other words, a system designed in accordance with an embodiment of the present disclosure need not include all of the features shown in any one of the figures, or all of the portions schematically shown in the figures. Further, selected features of one example embodiment may be combined with selected features of other example embodiments.

[0035] The foregoing description is illustrative, not limiting. It will be apparent to those skilled in the art that modifications and variations to the disclosed examples are not necessarily departing from the present disclosure. The scope of legal protection granted to the present disclosure can be determined only by considering the following claims.

Claims

1. a valve body defining a flow passage; a valve seat in the flow passage; a valve element initially in a closed position against the valve seat to block flow through the flow passage; a bonding material that secures the valve element in a closed position; at least one heater adjacent the valve seat and operable to heat the bonding material to a temperature at which the bonding material releases the valve element to move to an open position relative to the valve seat to open flow through the flow passage; A valve equipped with

2. 2. The valve of claim 1, wherein the bonding material is an alloy containing tin and indium, and the temperature is the melting point of the alloy.

3. 2. The valve of claim 1, wherein the bonding material is an alloy having a composition of a first weight percent tin and a second weight percent indium, the second weight percent being greater than the first weight percent.

4. 10. The valve of claim 1, wherein the at least one heater surrounds the valve seat.

5. 2. The valve of claim 1, wherein the valve seat defines a valve seating surface, and the at least one heater is disposed exterior to the valve body such that the valve seating surface intersects the at least one heater.

6. 2. The valve of claim 1, wherein the valve element carries the at least one heater.

7. 10. The valve of claim 1, wherein the at least one heater includes a first heater external to the valve body and a second heater internal to the valve body.

8. 10. The valve of claim 1, wherein the at least one heater includes first and second heaters external to the valve body.

9. 10. The valve of claim 1, further comprising a diamond-containing heat-conducting element between said at least one heater and said valve seat.

10. providing a valve including a valve body defining a flow passage, a valve seat within the flow passage, a valve element initially in a closed position against the valve seat to block flow through the flow passage, a bonding material securing the valve element in the closed position, and at least one heater adjacent to the valve seat; and activating the at least one heater to heat the bonding material to a temperature at which the bonding material releases the valve element and moves the valve element to an open position relative to the valve seat to open flow through the flow passage.

11. The method of claim 10, wherein the bonding material is an alloy containing tin and indium, and the temperature is the melting point of the alloy.

12. The method of claim 10, further comprising conducting heat from the at least one heater to the bonding material through a diamond-containing heat conducting element.

13. 11. The method of claim 10, wherein the at least one heater includes a first heater external to the valve body and a second heater internal to the valve body.

14. 14. The method of claim 13, wherein activating the at least one heater comprises activating only one of the first heater or the second heater.

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