Valve for closing a fluid line

Abstract

A valve for closing a fluid line, comprising: an inlet element with an inlet line; an outlet element with an outlet line; a closing element which, in a first state, allows a fluid passage between the inlet line and the outlet line and which, in a second state, closes the fluid passage, wherein the closing element, in the first state, is fixedly connected to the inlet element or the outlet element and, in the second state, is detached from the inlet element or the outlet element; an actuator which, when actuated, is configured to move the closing element from the first state towards the second state; and a pretension element which is pretensioned and is configured to move the closing element into the second state after actuation of the actuator.

Claims

1. A valve for closing a fluid line, comprising: an inlet element with an inlet line; an outlet element with an outlet line; a closer which, in a first state, allows a fluid passage between the inlet line and the outlet line and which, in a second state, closes the fluid passage, wherein the closer in the first state is fixedly connected to the inlet element or the outlet element and in the second state is detached from the inlet element or the outlet element; an actuator, including a wall defining an enclosure, which, when actuated, is configured to move the closer from the first state towards the second state; and a pretension element which is pretensioned and is configured to move the closer into the second state after actuation of the actuator, wherein the actuator and the pretension element are connected in parallel, such that a force of the actuator when actuated adds up with a force of the pretension element, and wherein the pretension element extends along the wall of the actuator.

2. The valve as claimed in claim 1, wherein the pretension element is arranged at least partly inside the actuator.

3. The valve as claimed in claim 1, wherein the inlet element has at least one radial bore which connects the inlet line with an exterior of the inlet element.

4. The valve as claimed in claim 3, wherein the at least one radial bore leads into a fluid passage chamber which connects the inlet line and the outlet line in a fluid-conducting manner.

5. The valve as claimed in claim 4, wherein a connecting element connects the inlet element and the outlet element in a fluid-conducting manner and together with the inlet element and the outlet element defines the fluid passage chamber.

6. The valve as claimed in claim 1, wherein a heater is thermally connected to the actuator, which comprises a shape-memory material, and at least one of the at least the inlet element or the outlet element is thermally decoupled from the heater by means of a thermal decoupler.

7. The valve as claimed in claim 1, wherein the closing closer is a cylindrical body which extends in the longitudinal direction of the valve and is guided predominantly inside the pretension element.

8. The valve as claimed in claim 1, wherein the closer in the second state is pressed into a seal seat, at least one of the closer and the seal seat being provided with a soft metal coating.

9. The valve as claimed in claim 1, wherein the pretension element extends along an interior surface of the actuator wall.

10. A spacecraft drive system comprising a valve as claimed in claim 1.

11. The spacecraft drive system of claim 10, comprising a satellite drive system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention are explained in greater detail in the following by means of the accompanying drawing, in which

(2) The FIG. is a longitudinal section of a valve according to an exemplary embodiment which is in an open starting state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(3) The FIG. shows a valve according to an exemplary embodiment, which valve is generally designated 10.

(4) The construction of the valve 10 will be described first, followed by its mode of operation.

(5) The valve 10 has a generally cylindrical shape and extends symmetrically along a longitudinal axis L, which coincides with the longitudinal axes of all the following valve components.

(6) The valve 10 has a tubular inlet element 12 which can be coupled with a fluid line 13, for example, of a spacecraft drive system 15, in particular, of a satellite drive system. Starting from such an end 14 suitable for coupling with a fluid line, the inlet element 12 extends in tubular form along the longitudinal axis L with an inlet line 16 in the form of a bore 16 of constant diameter. Along this bore 16 the cylindrical inlet element 12 has, in the longitudinal direction, a mounting portion 18 in the form of a cylindrical projection, which will be explained in greater detail hereinbelow, and, following this mounting portion 18, radially extending through-bores 20 through the inlet element 12, which connect the bore 16, that is to say the interior of the inlet element 12, with the exterior of the inlet element 12 in a fluid-permeable manner.

(7) The through-bores 20 here extend equidistantly along a plane through the inlet element 12 and through the longitudinal axis L, in each case two groups of four such through-bores 20 being arranged perpendicularly to one another. In addition, the through-bores 20 are inclined in their extension direction from the bore 16 outwards in the opposite direction to the end 14 of the inlet element 12. Following the through-bores 20, the bore 16 ends as a blind bore 22 of smaller diameter.

(8) In a middle region of the blind bore 22 along the longitudinal axis L, the wall thickness of the inlet element 12 is reduced to a minimum along the inlet element 12 by means of a notch 24 running radially outside the inlet element 12. This notch 24 constitutes a predetermined breaking point. The blind bore 22 is followed by a closing element 26 in the form of a solid cylinder, which extends in the form of a cylinder over two thirds of its length along the longitudinal axis L and in its final third widens radially annularly to a line portion 28 with through-bores 30 extending parallel to the longitudinal axis L, in order subsequently, from the same outside diameter as the first two thirds of the closing element 26, to terminate as a dome-shaped sealing piston 32.

(9) The valve 10 additionally has an outlet element 34 which, like the inlet element 12, can be coupled with a fluid line 35, for example, of the spacecraft drive system 15, in particular, of a satellite drive system. Starting from such an end 36 suitable for coupling with a fluid line, the outlet element 34 extends in tubular form along the longitudinal axis L with an outlet line 38 in the form of a bore 38 of constant diameter. The outlet element 34 is here in the form of a hollow cylinder with multiple steps, a first cylindrical projection 40 spaced apart from the end 36 merging into a second projection 41. Within the second projection 41, the bore 38 widens at the end of the outlet element 34 facing the closing element 26 to form a cone-shaped seal seat 42.

(10) The sealing piston 32 and/or seal seat 42 are provided with a soft metal coating, preferably a galvanic deposition of gold.

(11) A connecting element 44 of a NiCr or Ti alloy in the form of a valve housing 44 connects the inlet element 12 and the outlet element 34 by means of, in each case, a peripheral weld seam 46 in such a manner that the sealing piston 32 and the seal seat 42 are spaced apart from one another along the longitudinal axis L by a distance S in an unactuated starting state of the valve. The connecting element 44 is a stepped hollow cylinder, wherein a first region 48 of smaller inside diameter can be pushed onto the mounting portion 18 of the inlet element 12 and a second region 50 of larger inside diameter can be pushed onto the second projection 41 of the outlet element 41 in an abutting manner and flush therewith. The second region 50 has a larger inside diameter than the outside diameter of the inlet element 12 at the level of the through-bores 20 so that a fluid passage chamber 51 is present inside the connecting element 44 between the inlet element 12 and the outlet element 34.

(12) An actuator 52 extends in the form of a hollow cylinder along the inside wall of the connecting element 44 between the first region 48 and the line portion 28. At its end 54 facing the line portion 28, the actuator 52 is stepped radially inwards in the form of a cylinder at a distance from the closing element 26. The actuator 52 is a shape-memory actuator 52 which is compressed before being fitted into the connecting element 44, so that it does not expand until it reaches a phase transition temperature.

(13) A pretensioned pretension element in the form of a coil spring 56 extends along the inside wall of the actuator 52 between the first region 48 and the stepped end 54 of the actuator 52.

(14) An electric heating element 58 is adhesively bonded to the outer lateral surface of the connecting element 44. The heating element 58 extends along the longitudinal axis L in a hollow cylindrical manner concentrically with the actuator 52, so that it surrounds a large proportion of the actuator 52. The shortest distance of the heating element 58 from the inlet element 12 and the outlet element 34 is thereby always greater than the shortest distance of the heating element 58 from the actuator 52.

(15) Thermal decoupling elements 60 are located on the outer lateral surface of the first region 48 of the connecting element 44 and on the outer lateral surface of the first projection 40 of the outlet element 34. The decoupling elements 60 can be made of silicone, an elastomer or an oxide ceramic material, as well as a combination of these materials.

(16) The mode of operation of the valve 10 will now be described.

(17) In the first state of the valve 10 shown in the FIG., a fluid line is open. The arrows show the flow of fluid through the inlet line 16, the through-bores 20 of the inlet element 12, the fluid passage 51, the interior of the stepped end 54 of the actuator 52, the through-bores 30 of the line portion 28 and the outlet line 38.

(18) In a second state (not shown) of the valve 10, the actuator 52 has expanded after reaching a phase transition temperature due to the action of heat from the heating element 58 and, together with the pretension element 56, has reached a breaking force limit, which has led to the closing element 26 breaking away from the inlet element 12 at the notch 24. The pretension element 56 has then pressed the broken-off closing element 26 with its sealing piston 32 into the seal seat 42, in which the pretension element 56 also continues to reliably hold the sealing piston 32. In this second state, the fluid line is thus separated in a fluid-tight manner at the point between the through-bores 30 of the line portion 28 and the outlet line 38. As a result of the operation of breaking the closing element 26 away from the inlet element 12, this state is irreversible, that is to say the valve 10 can be closed one time only.

(19) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.