DE29810472U1 - Double safety valve - Google Patents

Description

Stuttgart, 25.05.1998 P7094Gm Rk/pa

Applicant:

Karl Dungs GmbH & Co.
Siemensstrasse 6-10
D-73660 Urbach

Representative :

Kohler Schmid + Partner
Patent attorneys
Ruppmannstrasse 27
D-70565 Stuttgart

Double safety valve

The invention relates to a double safety valve with two valves housed in a housing, the two axially displaceable valve plates of which are arranged coaxially to one another and are each lifted off from their respective valve seat by an axial movement in the opening direction against the spring pressure of a first or second closing spring.

Such a double safety valve has become known, for example, from DE 195 25 384 Al. Such double safety valves are used in particular as safety solenoid valves on the gas inlet side of gas heat generators .

In the double safety valve known from DE 195 25 3 84 Al, the two valve plates are arranged axially one above the other in a housing and each interact with its own valve seat. The valve plates are each part of two independent actuating elements, of which the second is guided axially displaceably in the first. The two actuating elements are opened by a common magnetic drive against the action of a closing spring, whereby when the magnet is switched off the two closing springs carry out the closing stroke of the two valve plates completely independently of each other. This means that the safety requirements for gas safety valves can be met.

Although the known double safety valve has already enabled a compact design and thus a space-saving unit on the one hand, on the other hand a significantly cheaper to manufacture, the axial height is still relatively large due to the valve plates and adjusting elements being both axially displaceable and arranged one behind the other. As a result of the ever-increasing miniaturization, a further reduction in the dimensions of the known double safety valve and in particular its axial height is generally sought. In addition, the assembly of the known double safety valve is very complex, since the second valve plate has to be threaded through the valve opening of the first valve plate.

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It is therefore the object of the invention to reduce the axial height of a double safety valve of the type mentioned above and to simplify assembly.

According to the invention, this object is achieved in a surprisingly simple and effective manner in that the first (outer) valve plate in the flow direction of the double safety valve surrounds the second (inner) valve plate and their two valve seats are combined to form a common valve seat that surrounds the only valve opening.

In contrast to the double safety valve known from DE 195 25 384 Al, two valve seats no longer have to be machined with a great deal of time and effort, but only a single valve seat. The assembly of the device is easier because the parts no longer have to be brought to two seats and a smaller device is easier to handle. Since less machining is required and the dimensions are smaller, the double safety valve according to the invention is also more cost-effective to manufacture. In addition to the fact that the axial height is significantly reduced, the flow values through the double safety valve according to the invention (multifunctional fitting) are comparable to those of a single seat valve due to the inventive reduction of the two valve functions to a common seat. The double safety valve according to the invention can be expanded to all sizes and valve types, meaning that a series with several variants such as a single solenoid valve, double solenoid valve or multifunctional valve with various regulators can be realized with the same housing.

It is understood that the invention is not limited to two valves or valve disks, but can also be applied to three or more coaxially arranged valve disks, each of which is nested within the other.

In an advantageous development of this embodiment, a common flat contact surface for both valve plates is provided on the common valve seat. This measure has the advantage that both valve seats can be manufactured by machining the common, in particular flat or stepless contact surface in a single operation.

In an alternative development, two axially offset contact surfaces for each valve plate can be provided on the common valve seat. For example, the two valve seats can be positioned at different levels on the common valve seat.

For optimum sealing effect, the elastomeric sealing agent of the valve plate that interacts with a flat contact surface is pointed, and the sealing agent that interacts with a pointed contact surface is flat. All variants of the seat arrangement are possible, e.g. both pointed, both flat, both at the same axial height, both axially offset from one another, or vice versa, etc.

Particularly preferred are further developments of the double safety valve in which a contact surface for an actuating element of a flow regulator that is axially movable in the valve opening is also provided on the common seat. This measure has the advantage that three functions (two valves and a flow regulator) can be carried out on one

seat. The closed position of the actuating element in the valve opening can be precisely defined by resting on the common valve seat. The actuating element can be a rod, for example, whose free, plate-shaped end protruding into the valve opening rests all around on the common valve seat in the closed position.

In an alternative development, a contact surface for an actuating element provided upstream of the two valve plates or valves can be provided on the common valve seat. In particular, if the actuating element overlaps the two valve plates in a pot-shaped manner, these are additionally shielded by the actuating element.

In order to be able to check the double safety valve according to the invention for its tightness, a leak test opening is provided on the common valve seat, which opens into the space between the two valve plates.

A separate guide for the inner valve plate or its adjusting element can be dispensed with if the inner valve plate or its adjusting element is guided axially displaceably within the outer valve plate or its adjusting element or within a guide element of the outer valve plate.

It is particularly advantageous if the outer valve plate is motion-coupled with the inner valve plate in the opening direction. This means that the outer valve plate is lifted off the common valve seat at the same time as the inner valve plate. In the closing direction, however, both valve plates are not motion-coupled so that they can be fully

can constantly perform their closing stroke independently of each other.

In a first development of this embodiment, the outer valve plate or its adjusting element can engage behind the adjusting element of the inner valve plate in the opening direction. The inner closing spring of the inner valve plate can be supported on the outer valve plate or on its adjusting element, e.g. on a circumferential shoulder or on the bottom of the outer adjusting element. The inner closing spring can be arranged, e.g. between the two adjusting elements, preferably in an annular gap, or in an opening of the inner adjusting element that is open in the opening direction.

In a second development, the outer valve plate can also overlap the inner valve plate in the opening direction and can be guided axially displaceably on the inner valve plate or on the inner actuating element. The outer valve plate is then carried along by the inner valve plate in the opening direction after a relative stroke of, for example, approx. 1 mm. In contrast to the double safety valve known from DE 195 25 384 Al, in which the outer valve plate, radially spaced from the magnet armature, is guided through its actuating element designed as a hollow armature, this development enables a smaller size and also a variety of design options, particularly in the spring design or in the application of force.

In an advantageous embodiment of this second development, the inner closing spring can be supported at one end on the housing and at the other end on the inner actuating element, in particular there within an opening that is open in the opening direction.

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A plate can be inserted at the bottom of the opening for support. Overall, this design offers more options for the spring sealing.

In particular, in the case of an outer valve plate that is slidably guided on the inner actuating element, this is sealed against the inner valve plate, e.g. via an O-ring or a lip seal, with the latter achieving a longer service life.

In one embodiment of the invention, it is provided that the outer actuating element engages behind the inner actuating element in the opening direction, is axially displaceable relative to the outer valve plate and is subjected to force by the outer closing spring when it is in pressure contact with the outer valve plate. This actuating element of the outer valve plate only serves to ensure that a valve still closes in the event of a fault (jamming of the outer actuating element in its housing guide (magnetic closure sleeve) or jamming of the inner actuating element (magnetic armature) in the outer actuating element). Since the actuating element no longer has to fulfill a sealing function, the inner closing spring can be guided through the actuating element and rest on the magnetic closure sleeve. Separating the actuating element and the outer valve plate simplifies the manufacture of the parts.

In particularly advantageous embodiments, the outer valve plate is attached to a guide element that can be moved axially in the housing. A sleeve or a tube can be used as a guide element, which leads to further simplification in the manufacture of the double safety valve. The guide element can be caulked to the outer valve plate or connected in some other way.

In a further embodiment, the outer closing spring is supported on the inner actuating element and on the outer valve plate or on its actuating or guide element. In both variants of the support, when the double safety valve is closed, the outer closing spring applies the force to close both valve plates or valves. Both valves because the inner one is supported against the outer closing spring and the latter is thus relieved. The force of the inner closing spring closes the outer valve. If the outer valve does not close, the inner closing spring is designed in such a way that there is still enough force to close the inner valve in this case too.

In order to be able to manufacture the double safety valve at particularly low production costs, the housing of the two valves is preferably made as a die-cast part or from an extruded profile. Even with such an extruded profile, it is possible to attach the leak test required for gas safety valves to the side.

Further advantages of the invention emerge from the description and the drawing. Likewise, the features mentioned above and those listed below can be used individually or in combination in any combination. The embodiments shown and described are not to be understood as an exhaustive list, but rather are exemplary in nature for the description of the invention.

The invention is illustrated in the drawing and is explained in more detail using exemplary embodiments. It shows:

Fig. 1 shows a first embodiment of the double safety valve according to the invention in a longitudinal section;

Fig. 2 is an enlarged view of the double safety valve of Fig. 1 in the area of its valve opening corresponding to section II;

Fig. 3 shows, in an enlarged view corresponding to Fig. 2, a second embodiment of the double safety valve according to the invention, wherein the inner closing spring is supported on the bottom of the outer actuating element;

Fig. 4 in an enlarged view corresponding to Fig. 2 a third embodiment of the double safety valve according to the invention, wherein the outer actuating element pressurizes the outer valve plate;

Fig. 5 shows, in an enlarged view corresponding to Fig. 2, a fourth embodiment of the double safety valve according to the invention, wherein the outer valve plate is guided in the housing by means of a guide element;

Fig. 6 shows, in an enlarged view corresponding to Fig. 2, a fifth embodiment of the double safety valve according to the invention, wherein the outer closing spring is supported on the inner actuating element and on the outer valve plate; and

Fig. 7 shows, in an enlarged view corresponding to Fig. 2, a sixth embodiment of the double safety valve according to the invention with a regulator arranged in front of the valve disks.

In Fig. 1, 1 denotes a double safety valve, the two valves 2 and 3 of which are connected in series and housed in a common housing 4. This housing 4 is divided by a valve opening 5 into a gas inlet chamber 6 and a gas outlet chamber 7, with the valve opening 5 being surrounded by a valve seat 8.

The first (outer) valve 2 on the input side consists of an annular first (outer) valve plate 9, an actuating element (hollow armature or sleeve) 10 connected to the valve plate 9 and a first (outer) closing spring 11. The second (inner) valve 3 on the output side consists of an annular first (inner) valve plate 12, a magnetic armature 13 connected to this valve plate 12 and a second (inner) closing spring 14.

The two valves 2, 3 or their valve plates 9, 12 are arranged coaxially with respect to a common axis 15, where the outer valve plate 9 surrounds the inner valve plate 12 in a ring shape. The valve seat 8 serves with its contact surface 8a (Fig. 2) as a common valve seat for both valve plates 9, 12, which are each lifted off the common valve seat 8 by an axial movement in the opening direction 16. A common magnetic drive 17 with a magnetic coil 18 and a guide opening 19, in which the actuating element 10 is guided axially displaceably, is used to open the two valves 2, 3. The magnetic armature 13 is in turn

guided axially displaceably in the actuating element 10, whereby the pot-shaped actuating element 10 engages behind the magnet armature 13 in the opening direction 16 and is thus motion-coupled with the magnet armature 13 in the opening direction 16.

The outer closing spring 11 is supported on the housing 4, while the inner closing spring 14 is supported on a circumferential shoulder 20 inside the actuating element 10. In the closed state of the double safety valve 1 shown, the outer closing spring 11 therefore applies the force to close both valve plates 9, 12 or both valves 2, 3. Both valves because the inner closing spring 14 is supported against the outer closing spring 11 and the latter is thus relieved.

When the magnetic coil 18 is excited, magnetic lines of force are created, which attract the magnetic armature 13 together with the inner valve plate 12 in the opening direction 16. Due to the movement coupling, the inner valve plate 12 and the outer valve plate 9 are simultaneously lifted off the common valve seat 8. After the magnetic coil 18 is switched off, the closing springs 11, 14 cause each valve 2, 3 to close independently of one another. The force of the inner closing spring 14 closes the inner valve plate 12 or the inner valve 3.

In the event that the outer valve 2 does not close, e.g. because the actuating element 10 is jammed in the guide opening 19, the inner closing spring 14 is designed so that there is still enough force to close the inner valve plate 12 or the inner valve 3 in this case too. This means that the inner valve 3 closes when the outer valve 2 closes (stroke of the inner valve plate

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12 relative to the outer valve plate 9: 1 mm) and if the outer valve 2 should not close due to a malfunction (stroke of the inner valve plate 12 relative to the outer valve plate 9: nominal stroke + 1 mm). In contrast to known double safety valves with valves arranged axially one behind the other, no stronger magnet is required to open the two valves 2, 3, despite the stronger outer closing spring 11, since the outer closing spring 11, as described above, is relieved by the inner closing spring 14.

In order to regulate the flow through the valve opening 5, an adjusting element 21 with a Y-shaped cross section is provided, which passes through the valve opening 5 and is axially displaceable. The adjusting element 21 is adjusted by means of a flow regulator 22 known per se in accordance with a desired output pressure in the gas outlet chamber 7. In its closed position shown in Fig. 2, the adjusting element 21 also rests with its free plate-shaped end on the flat contact surface 8a of the common valve seat 8, the diameter of the plate-shaped end being larger than the diameter of the valve opening 5.

Compared to this first embodiment, the double safety valve 101 shown in Fig. 3 differs in that the inner closing spring 114 is accommodated within an opening (blind hole) 123 in the magnet armature 113 and is supported at one end on the magnet armature 113 and at the other end on the base 124 of the pot-shaped actuating element 110. This arrangement offers many possibilities for the spring design. The advantage of the dependently supported closing springs 111 and 114 is that in the event of the magnet armature 113 jamming in the actuating element 110, the strong outer closing spring 111, which previously provided the closing force for the two

Valve disk 109, 112 closes the remaining intact outer valve disk 109.

In this embodiment, the common valve seat 108 does not have a common flat contact surface for both valve disks 109 and 112, but the two contact surfaces 108a and 108b are arranged axially offset from one another. The outer contact surface 108a is pointed and the elastomeric sealing means of the outer valve disk 109 that interacts with this contact surface 108a is flat. In contrast, the inner contact surface 108b, which simultaneously serves as a contact surface for the actuating element 21, is flat and the elastomeric sealing means of the inner valve disk 112 that interacts with this contact surface 108b is pointed. Furthermore, a leak test opening 135 is provided on the common valve seat 108, which leads into the annular space between the two valve disks 109, 112, so that a leak test of the double seat valve 101 is possible.

In the third embodiment of the double safety valve 201 shown in Fig. 4, the outer valve plate 209 is guided axially displaceably directly on a guide section 225 of the magnet armature 213 and is not firmly connected to the outer valve plate 209. The sealing of the outer valve plate 209 against the inner valve plate 212 takes place on the guide section 225 by means of an O-ring seal 226. The guide element 210 no longer serves to position the first valve plate 209, but only to ensure that a valve still closes in the event of a fault (jamming of the guide element 210 in its housing guide (magnetic closure sleeve 227) or jamming of the magnet armature 213 in the guide element 210). The outer valve plate 209, which overlaps the inner valve plate 212, is moved after a relative stroke of

1 mm from the inner valve plate 212. Since the
Guide element 210 no longer fulfills a sealing function
the inner closing spring 214 can be guided through an opening 22 8 in the guide element 210 and supported on the underside 229 of the magnetic closure sleeve 227. By
Guide element 210 the magnet armature 213 in the opening direction
of the two valves, it is in the opening direction
coupled to the magnet armature 213. The outer
Closing spring 211 for the outer valve plate 209 pressurizes the guide element 210 in contact with the outer valve plate 209 and is therefore also responsible for the forced movement of the guide element 210 so that it does not
Movement can "stick". However, there is no longer any mutual support between the two closing springs 211, 214, which is possible by closing the opening 228.

In the double safety valve 3 01 shown in Fig. 5, the tubular guide element 310 engages behind
the magnet armature 313 , so that it is not coupled in motion with the magnet armature 313. The guide element 310 serves
only the additional guidance of the outer valve disk 3 09, to which it is connected at one end, e.g. caulked. The other end of the guide element 310 is guided axially displaceably in the housing 3 04. The two valve disks 309 and 312 are sealed against each other in this embodiment by a lip seal 326. Furthermore, the inner closing spring 314 is attached to the magnet armature 313 and to a sleeve in front of the magnet closure sleeve
328 inserted board 329 , while
the outer closing spring 311 is supported on the housing 3 04 and on the outer valve plate 309.

In the embodiment of the double safety valve 401 according to Fig. 6, the outer closing spring 411 for the outer valve plate 409 , which is seated on the guide section 425 , is supported on the latter and on the magnet armature 413. This means that the inner closing spring 414 for the inner valve plate 412 must be approximately twice as strong, since the two closing springs 411, 414 support each other. Oscillation of the outer valve plate 409 is better possible with this measure, and the more force is introduced centrally, the better.

The double safety valve 501 shown in Fig. 7 differs in its construction from the double safety valve 401 only in that the actuating element 521 of a flow regulator is arranged in the flow direction upstream of the two valves or valve plates 509, 512. The actuating element 521 comprises a regulator pot 530 which additionally shields the two valves and in which a regulator membrane 533 is held between a lower and an upper membrane plate 531, 532. As in the other embodiments, the actuating element 521 is arranged coaxially to the valve plates 509, 512, but a separate regulator seat 534 is attached to the common valve seat 508 of the two valve plates 509, 512.

Claims (22)

Stuttgart, 25.05.1998 P7094Gm Rk/pa Protection claims Double safety valve (1; 101; 201; 301; 401; 501) with two valves (2, 3) housed in a housing (4; 2 04; 3 04), the two axially displaceable valve plates (9, 12; 109, 112; 209, 212; 309, 312; 409, 412; 509, 512) of which are arranged coaxially to one another and are each lifted off from their respective valve seats by an axial movement in the opening direction (16) against the spring pressure of a first or a second closing spring (11, 14; 111, 114; 211, 214; 311, 314; 411, 414), characterized, that the first (outer) valve plate (9; 109; 209; 309; 409; 509) in the flow direction of the double safety valve (1; 101; 201; 301; 401; 501) surrounds the second (inner) valve plate (12, - 112; 212; 312; 412; 512) and their two valve seats are combined to form a common valve seat (8; 108; 508) which surrounds the only valve opening (5). 2. Double safety valve according to claim 1, characterized in that a common flat contact surface (8a) for both valve plates (9, 12) is provided on the common valve seat (8). 3. Double safety valve according to claim 1, characterized in that on the common valve seat (108; 508) two axially offset contact surfaces (108a, 108b) for each have a valve plate (109, 112; 209, 212, - 309, 312; 409, 412; 509, 512). 4. Double safety valve according to one of the preceding claims, characterized in that in the case of a flat contact surface (8a; 108b) the elastomeric sealing means of the valve plate (9; 12; 112; 212; 312; 412; 512) interacting with this is pointed and in the case of a pointed contact surface (108a) the sealing means of the valve plate (109; 209; 309; 409; 509) interacting with this is flat. 5. Double safety valve according to one of the preceding claims, characterized in that a contact surface (8a, - 108b) for an actuating element (21) of a flow regulator (22) that is axially movable in the valve opening (5) is also provided on the common seat (8; 108). 6. Double safety valve according to one of the preceding claims, characterized in that a contact surface (regulating surface 534) for an actuating element (521) provided upstream of the two valve plates (509, 512) is also provided on the common valve seat (508). 7. Double safety valve according to one of the preceding claims, characterized in that a leak test opening (135) is provided on the common valve seat (108), which opens into the space between the two valve plates (109, 112). 8. Double safety valve according to one of the preceding claims, characterized in that the inner valve plate (12; 112; 212; 312; 412; 512) or its actuating element (magnetic armature 13; 113; 213; 313; 413) of the is guided axially displaceably within the outer valve plate or its adjusting element (10; 110,- 210) . or within a guide element (310; 410) of the outer valve plate (9; 109; 209; 309; 409; 509). 9. Double safety valve according to one of the preceding claims, characterized in that the outer valve plate (9; 109; 209; 309; 409; 509) is coupled in terms of movement to the inner valve plate (12; 112; 212; 312; 412; 512) in the opening direction (16). 10. Double safety valve according to claim 9, characterized in that the outer valve plate (9; 109) or its adjusting element (10; 110) engages behind the adjusting element (magnetic armature 13; 113) of the inner valve plate (12; 112) in the opening direction (16). 11. Double safety valve according to claim 9 or 10, characterized in that the second (inner) closing spring (14; 114) of the inner valve plate (12; 112) is supported on the outer valve plate (9; 109) or on its actuating element (10, - 110). 12. Double safety valve according to claim 11, characterized in that the inner closing spring (14) is supported on a circumferential shoulder (20) of the outer actuating element (10). 13. Double safety valve according to claim 11, characterized in that the inner closing spring (114) is supported on a base (124) of the outer actuating element (110). 14. Double safety valve according to claim 13, characterized in that the inner closing spring (114) is arranged in an opening (123) of the inner actuating element (magnetic armature 113)). 15. Double safety valve according to claim 9, characterized in that the outer valve plate (209; 309; 409; 509) overlaps the inner valve plate (212; 312; 412; 512) in the opening direction (16). 16. Double safety valve according to claim 15, characterized in that the outer valve plate (209; 309; 409; 509) is guided axially displaceably on the inner valve plate or on the inner actuating element (magnetic armature (213; 313, - 413). 17. Double safety valve according to claim 15 or 16, characterized in that the inner closing spring (214; 314; 414) is supported at one end on the housing (204; 304) and at the other end on the inner actuating element (magnetic armature 213; 313, - 413), in particular there within an opening (223) open in the opening direction (16). 18. Double safety valve according to one of claims 15 to 17, characterized in that the outer valve plate (209; 309; 409; 509) is sealed from the inner valve plate (212; 312; 412; 512). 19. Double safety valve according to one of claims 15 to 18, characterized in that the outer actuating element (210) engages behind the inner actuating element (magnetic armature 213) in the opening direction (16), is axially displaceable relative to the outer valve plate (209) and is subjected to force by the outer closing spring (211) in pressure contact with the outer valve plate (209). 20. Double safety valve according to one of claims 15 to 18, characterized in that the outer valve plate (309; 409; 509) is attached to a guide element (310; 410; 510) which is axially displaceable in the housing (304). 21. Double safety valve according to one of claims 15 to 20, characterized in that the outer closing spring (411) is supported on the inner actuating element (magnetic armature 413) and on the outer valve plate (409) or on its actuating or guide element (410). 22. Double safety valve according to one of the preceding claims, characterized in that the housing (4; 204; 304) of the two valves (2, 3) is formed by an extruded profile or as a die-cast part.