Safety valve for a pressure vessel, comprising a discharge line

Abstract

A safety valve for a pressure vessel has a discharge line which extends away from a pressure relief unit. A substance fills an internal volume of the discharge line. At least one insulation element which is configured for at least reducing the thermal transmission in the discharge line in the axial direction of the discharge line is provided in the discharge line.

Claims

1. A safety valve having a pressure relief unit for a pressure vessel, comprising: a discharge line which extends away from the pressure relief unit, wherein a substance fills an internal volume of the discharge line, a separate bursting installation functions as a bursting installation, the separate bursting installation not being the discharge line itself, the discharge line is equipped with the bursting installation, wherein the discharge line has a first distal end that is attached to the pressure relief unit and a second distal end that is disposed spaced apart from the pressure relief unit, wherein the second distal end is a free end of the discharge line; and the bursting installation is provided on the free end of the discharge line.

2. The safety valve as claimed in claim 1, wherein the bursting installation is disposed and configured such that the substance, after a bursting event, escapes to an environment such that a depressurization arises in the discharge line and in the pressure relief unit.

3. The safety valve as claimed in claim 1, further comprising: at least one insulation element which is configured for at least reducing thermal transmission at least in an internal volume in an axial direction of the discharge line.

4. The safety valve as claimed in claim 3, wherein the thermal transmission in a radial direction of the discharge line on account of the at least one insulation element is not changed or changed only to a limited extent.

5. The safety valve as claimed in claim 4, wherein the at least one insulation element is configured for subdividing the internal volume of the discharge line into a plurality of part-volumes.

6. The safety valve as claimed in claim 5, wherein the at least one insulation element is configured so as to be displaceable in the axial direction of the discharge line.

7. The safety valve as claimed in claim 3, wherein the at least one insulation element is configured for subdividing the internal volume of the discharge line into a plurality of part-volumes.

8. The safety valve as claimed in claim 7, wherein the at least one insulation element is configured for suppressing a fluid communication between adjacent part-volumes; and/or the at least one insulation element is configured for establishing a fluid communication between adjacent part-volumes in the case of the pressure differential limit value being exceeded.

9. The safety valve as claimed in claim 8, wherein the at least one insulation element has at least one passage.

10. The safety valve as claimed in claim 3, wherein the at least one insulation element is configured so as to be displaceable in the axial direction of the discharge line.

11. The safety valve as claimed in claim 10, wherein the at least one insulation element is configured and disposed in the discharge line in such a manner that said insulation element is displaced within the discharge line in the axial direction of the discharge line when a pressure differential limit value between adjacent part-volumes is exceeded.

12. The safety valve as claimed in claim 10, wherein the at least one insulation element is configured for suppressing a fluid communication between adjacent part-volumes; and/or the at least one insulation element is configured for establishing a fluid communication between adjacent part-volumes in the case of the pressure differential limit value being exceeded.

13. The safety valve as claimed in claim 3, wherein the at least one insulation element at least in regions is configured as a disk, and the at least one insulation element in a central region and/or in a peripheral region is configured so as to be flexural and/or burstable.

14. The safety valve as claimed in claim 13, wherein the at least one insulation element has at least one passage.

15. The safety valve as claimed in claim 3, wherein the safety valve has at least two insulation elements which by way of at least one spacer are mutually spaced apart.

16. The safety valve as claimed in claim 15, wherein the at least one spacer is configured so as to be flexural, and in a peripheral region and/or in a central region the spacer is connected to the at least one insulation element, or at least in regions bears on the at least one insulation element.

17. A safety valve having a pressure relief unit for a pressure vessel, comprising: a discharge line which extends away from the pressure relief unit, wherein a substance fills an internal volume of the discharge line and wherein a separate bursting installation functions as a bursting installation, the separate bursting installation not being the discharge line itself; and at least one insulation element which is configured for at least reducing thermal transmission at least in an internal volume in an axial direction of the discharge line, wherein the at least one insulation element is configured for subdividing the internal volume of the discharge line into a plurality of part-volumes, and the at least one insulation element is configured and disposed in the discharge line in such a manner that said insulation element is displaced within the discharge line in the axial direction of the discharge line when a pressure differential limit value between adjacent part-volumes is exceeded.

18. A safety valve for a pressure vessel, comprising: a pressure relief unit; a discharge line which extends away from the pressure relief unit, wherein a substance fills an internal volume of the discharge line, a separate bursting installation functions as a bursting installation, the separate bursting installation not being the discharge line itself, the discharge line is equipped with the bursting installation, wherein the discharge line has a first distal end that is attached to the pressure relief unit and a second distal end that is disposed spaced apart from the pressure relief unit, wherein the second distal end is a free end of the discharge line; and the bursting installation is provided on the free end of the discharge line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic cross-sectional view of the safety valve 100.

(2) FIG. 2 is a schematic cross-sectional view of a discharge line 120.

(3) FIG. 3 is a further schematic cross-sectional view of a discharge line 120.

(4) FIG. 4 is a further embodiment of a discharge line 120.

(5) FIG. 5 is a cross-sectional view along the line C-C of FIG. 4.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) FIG. 1 shows a cross-section through a safety valve 100 disclosed herein. The safety valve 100 is attached to one end of a pressure vessel 200. The assembly of the safety valve 100 on the pressure vessel 200 can be designed in various ways. The safety valve 100 is typically attached directly to the pressure vessel 200. The safety valve 100 comprises a pressure relief unit 110 and a discharge line 120. The discharge line 120 is in fluid communication with an internal chamber 111 of the pressure relief unit 110. A piston 112 which in turn is pretensioned by pretensioning means (presently a spring) 113 is disposed in the internal chamber 111.

(7) The discharge line 120 and the chamber 111 of the pressure relief unit 110 are filled with the substance S, presently a water/glycol mixture S. A plurality of insulation elements 300 which presently are embodied as disks, each having one passage, are disposed in the discharge line 120. The insulation elements 300 are disposed so as to be mutually spaced apart and subdivide the internal volume I.sub.gas of the discharge line 120 into a plurality of part-volumes I.sub.1, I.sub.2, I.sub.3. The part-volumes I.sub.1, I.sub.2, I.sub.3 are in mutual fluid communication by way of the passages in the insulation elements 300. Therefore, an almost identical operating pressure (for example, such as 1.3 bar (=bar atmospheric pressure) to 1.5 bar at room temperature in the case of a water-glycol mixture) prevails in all part-volumes I.sub.1, I.sub.2, I.sub.3 and in the chamber 111. The insulation elements 300 furthermore have the effect that the thermal transmission W.sub.A in the discharge line 120 in the axial direction A is at least below that of a design embodiment without insulation elements 300. The insulation elements 300 thus reduce the thermal transmission W.sub.A which would otherwise, for example, be forced by the fluid flow from the free end in the direction of the pressure relief unit 110 and by the Brownian molecular motion.

(8) Should a thermal event (presently illustrated as a local thermal flow Q), for example a local flame, now act locally on the discharge line 120, the part-volume I.sub.2 is thus heated. Since the part-volume I.sub.2 at both sides is delimited by insulation elements 300, comparatively little heat is transmitted away from the part-volume I.sub.2. The part-volume I.sub.2 is thus heated more rapidly than a volume of equal size which is not delimited by insulation elements 300. A phase change which is associated with a significant increase in the pressure p.sub.2 (for example to 2 bar) in the part-volume I.sub.2 can thus advantageously be implemented by way of a minor thermal flow {dot over (Q)} in a part-volume I.sub.2. Since the individual part-volumes I.sub.1, I.sub.2, I.sub.3 are in fluid communication by way of respective passages, and the liquid remains largely non-compressible, the pressure in the other part-volumes also rises. A bursting installation 123 is advantageously provided in the discharge line 120 in the design embodiment shown here. The bursting installation 123 is conceived such that the bursting installation 123 bursts when the pressure rises to a pressure above a bursting installation trigger pressure (for example 1.8 bar). When the bursting installation 123 is destroyed, the liquid escapes from the discharge line 120. This has the effect that the liquid also escapes from the chamber 111. The pressure in the chamber 111 now drops to below a chamber trigger pressure (for example 1.1 bar) of the pressure relief unit 110. The counterforce to the pretensioning means 113 that is applied on account of the pressure in the chamber 111 is now no longer sufficient in order for the piston 112 to be held in the flow-blocking position. Therefore, the piston is displaced from the flow-blocking position to a position in which the flow of fuel through the pressure relief unit 110 is enabled. To this end, a plug 115 can escape into a clearance of the piston 112, for example. The escaped plug 115 vacates the flow path 500 to the environment. The pressure in the pressure vessel 200 is then diminished in a safe manner in this position of the piston 112.

(9) According to the solution shown here, the thermal event Q first causes a buildup of pressure to a pressure value above the bursting installation trigger pressure. After the destruction of the bursting disk a depressurization takes place in the discharge line 120 and triggering of the pressure relief unit 110 thus takes place. Such a design embodiment has the advantage that potential leakages in the discharge line 120 would also lead to a depressurization in the discharge line 120 and thus to the discharge of fuel. Such a system is thus safer than systems in which an increased pressure moves the pressure relief unit 110 directly to an open position (for example without a bursting installation). In principle, however, the latter would also be within the scope of the technology disclosed herein.

(10) FIG. 2 shows an enlarged detailed view of two insulation elements 300, 300′, which delimit the part-volume I.sub.2. The insulation elements 300, 300′ are positioned by a spacer means 320, presently a flexible bar or a dimensionally stable thread, respectively, in particular in such a manner that the insulation elements 300, 300′ are mutually spaced apart and define a part-volume I.sub.2 of the internal volume I.sub.gas of the discharge line 120. The insulation elements 300, 300′ illustrated with dashed lines are in the state in which the substance S in the part-volume I.sub.2 has been heated in such a manner that at least a partial phase change has taken place. In that event, the pressure p2 in the part-volume 12 increases sharply. The increase in pressure has the effect that a pressure differential arises between adjacent part-volumes. Should this pressure differential exceed a specific value, the pressure differential causes the peripheral regions Ra, Ra′ of the insulation elements 300, 300′ to flex. A fluid communication between adjacent part-volumes is created in this instance. A pressure equalization is associated with the fluid communication such that the part-pressures p.sub.1, p.sub.2, p.sub.3 in the part-volumes I.sub.1, I.sub.2, I.sub.3 are substantially identical. As has already been described in the context of FIG. 1, the increase in pressure in the discharge line 120 causes the destruction of the bursting disk on account of a pressure above the bursting installation trigger pressure (for example 2 bar) in the discharge line 120. A depressurization to a pressure value (for example 1 bar) then arises in the discharge line 120, said pressure value being below the normal operating pressure (for example 1.5 bar) in the discharge line 120. This in turn has the effect that the insulation elements 300, 300′ flex in the opposite direction (thus to the left in FIG. 2). In turn, a fluid communication between adjacent part-volumes is thus created which has the effect that a depressurization arises in the chamber 111. The piston 111 of the pressure relief unit 110 is displaced and thus opens the safety valve 100 (not shown in FIG. 2).

(11) FIG. 3 shows an enlarged view of the insulation elements 300, 300′ of FIG. 1. The passages 310, 310′ which separate the different part-volumes I.sub.1, I.sub.2, I.sub.3 from one another are disposed in the central region. In the design embodiment shown here, the insulation elements 300, 300′ are fixedly connected to the discharge line 120. The insulation elements 300, 300′ could also be configured without passages 310, 310′. Furthermore, the insulation elements 300, 300′ could be held in the discharge line 120 only in such a manner that the insulation elements 300, 300′ are displaced when a pressure differential limit value between adjacent part-volumes I.sub.1, I.sub.2, I.sub.3 is exceeded.

(12) FIG. 4 shows a further embodiment of the insulation elements 300, 300′. The insulation elements 300, 300′ comprise a disk-shaped region, spacer elements 320, 320′ extending away from the latter. The spacer elements 320, 320′ here are expediently configured as stays or webs, respectively, and space apart the disk-shaped regions of adjacent insulation elements 300, 300′. Passages 310, 310′ are again disposed in the central regions of the disk-shaped regions.

(13) FIG. 5 shows a cross-sectional view along the line C-C. The passage 310 is shown in the central region, and two stays 320 are shown here in the peripheral region.

(14) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.