STEAM TRAP AND ASEPTIC DOUBLE SEAT VALVE

Abstract

A steam trap is provided comprising a housing having formed therein a seat for a closure element between a steam and/or condensate inlet and an outlet, the closure element being adapted to be switched between a closed position in the seat and an open position raised from the seat, an annular gap is formed upstream of the seat in the final phase of the switching movement to the closed position and at the end position of the closed position, said annular gap being used for at least pre-filtering condensate and preventing particles from getting stuck in the seat as well as clogging of a nozzle.

Claims

1. A steam trap comprising a housing having formed therein a seat for a closure element between a steam and/or condensate inlet and an outlet, the closure element being adapted to be switched by a drive between a closed position in the seat and an open position raised from the seat, wherein at least at the end position of the closed position, an annular gap is formed upstream of the seat in a flow direction of steam and/or condensate from the inlet into the outlet, said gap for preventing particles from getting stuck in the seat as well as clogging of a nozzle that is formed between the closure element and the seat, the gap being formed by a distance of the closure element from the housing.

2. The steam trap according to claim 1, wherein the gap is delimited with a substantially constant width by an undercut annular flange in a small-diameter end region of the closure element, which is configured as a valve cone, and by the inlet, which is configured as an axial, cylindrical extension of a small-diameter end of the seat, the annular flange and the extension having identical contours and being circular or polygonal.

3. The steam trap according to claim 1, wherein a circumferential annular flow space extending, at least substantially, parallel to the annular gap is provided, when seen in the flow direction, downstream of the annular gap and substantially adjacent to the annular gap, in the closure element configured as a valve cone.

4. The steam trap according to claim 2, wherein the undercut of the annular flange is formed by a circumferential groove provided in the valve cone and defining an annular flow space.

5. The steam trap according to claim 4, wherein when seen in cross-section, the annular flange has a convex curvature and the circumferential groove has a concave curvature with a rounded transition, and that the seat and the valve cone have frusto-conical circumferential surfaces as a seating area and as a sealing face.

6. The steam trap according to claim 4, wherein at the closed position, an edge of the circumferential groove is located approximately on the level of the small-diameter end of the seat, said edge facing away from the annular flange.

7. The steam trap according to claim 6, wherein a sealing face of the valve cone or/and a seating area of the seat have provided therein at least one control notch at least at one circumferential position, said control notch extending parallel to the cone axis and beginning in the edge of the circumferential groove; and wherein the control notch is an approximately partially cylindrical milled out portion.

8. The steam trap according to claim 7, wherein by means of the at least one control notch, a two-part nozzle is formed at least at the closed position, said nozzle beginning, when seen in the flow direction, at the circumferential groove and increasing in width subsequently.

9. The steam trap according to claim 7, wherein the control notch extends up to a large-diameter end of the seat and of the valve cone, respectively, when the seat and the valve cone have identical taper angles, whereas it ends at a distance from the large-diameter end of the seat and of the valve cone, respectively, if the taper angle of the valve cone is smaller than the taper angle of the seat.

10. The steam trap according to claim 9, wherein in the housing, the small-diameter end of the seat and of the valve cone are positioned upstream of the respective large-diameter end, when seen in the flow direction.

11. The steam trap according to claim 8, wherein a gap width of the annular gap is smaller than a radial depth of the control notch at a narrowest point of the nozzle.

12. The steam trap according to claim 7, wherein a cross-sectional area of the annular gap is a multiple of the narrowest cross-section of the control notch and of the nozzle, respectively.

13. An aseptic double seat valve of a beverage or food filling plant, comprising a leakage chamber, which is adapted to be flushed with condensate and to be sterilized with steam, wherein the double seat valve comprises a switchable steam trap comprising a housing having formed therein a seat for a closure element between a steam and/or condensate inlet and an outlet, the closure element being adapted to be switched by means of a drive between a closed position in the seat and an open position raised from the seat, wherein at least at the end position of the closed position, an annular gap is formed upstream of the seat in a flow direction of steam and/or condensate from the inlet into the outlet, said gap for preventing particles from getting stuck in the seat as well as clogging of a nozzle that is formed between the closure elements and the seat, the gap being formed by a distance of the closure element from the housing wherein the inlet is connected to the leakage chamber.

14. A beverage filling plant comprising a valve, which comprises a steam trap comprising a housing having formed therein a seat for a closure element between a steam and/or condensate inlet and an outlet, the closure element being adapted to be switched by means of a drive between a closed position in the seat and an open position raised from the seat, wherein characterized in that at least at the end position of the closed position, an annular gap used for pre-filtering condensate is formed upstream of the seat in a flow direction of the steam and/or condensate from the inlet into the outlet, said gap for preventing particles from getting stuck in the seat as well as clogging of a nozzle that is adapted to be formed between the closure elements and the seat, the gap being formed by a distance of the closure element from the housing.

15. The steam trap according to claim 1, wherein the steam trap is for aseptic double seat valves in beverage or food filling plants.

16. The steam trap according to claim 1, wherein the annular gap is used for at least pre-filtering the condensate.

17. The steam trap according to claim 11, wherein the annular gap ranges from approximately 0.1 to 0.4 mm.

18. The steam trap according to claim 12, wherein the multiple of the narrowest cross-section is about twelve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Making reference to the drawing, embodiments of the present disclosure will be explained, in the case of which:

[0029] FIG. 1 shows a longitudinal section of the steam trap at the closed position.

[0030] FIG. 2 shows, on an enlarged scale, a detail emphasized in FIG. 1 by a circle.

[0031] FIG. 3 shows a perspective view of a valve cone of the steam trap.

[0032] FIG. 4 shows a longitudinal section of the steam trap at the end of the initial phase of an opening switching movement and at the beginning of a final phase of the closing switching movement, respectively.

[0033] FIG. 5 shows, on an enlarged scale, a detail emphasized in FIG. 4 by a circle.

[0034] FIG. 6 shows a longitudinal section of the steam trap at the open position of the valve cone.

DETAILED DESCRIPTION

[0035] FIG. 1 to FIG. 6 show a steam trap A, which may be adapted to be combined with a double seat valve 1 of a food or beverage filling plant (not shown), but which may also be used for other intended purposes, where a heated gaseous medium, such a steam, is processed. The steam trap A corresponds largely to the steam trap described in DE 10 2016 203 557 A, which has a prior time rank and which is herewith incorporated by reference.

[0036] In the case shown as a non-limiting example, the steam trap A is connected via an inlet 12 (inlet line) to a leakage chamber 9 of the double seat valve 1, at least the leakage chamber 9 having supplied thereto steam and/or condensate for flushing and sterilization cycles via a line 6.

[0037] The steam trap A in FIG. 1 comprises a housing 16 delimiting a valve chamber 17 and comprising a seat 19 with a conical seating area 21 for a conical sealing face 20 of a valve cone 18. The seat 19 conically increases in width from the inlet 12 in the flow direction R towards the valve chamber 17, which is connected to the outlet 13 that may be connected e.g. to an impact absorber 15 for collecting condensate and contaminations. At the closed position shown in FIG. 1, the valve cone 18 extends substantially fully into the seat 19 from below, so that the sealing face 20 and the seating area 21 as a seat valve would sealingly shut off the passage in the flow direction R from the inlet 12 to the outlet 13. However, the valve cone 18 and the seat 19 define, at the closed position shown, with at least one control groove 22 a two-part nozzle D, through which a limited flow (e.g. for a sterilization cycle) is given even at the closed position. In the embodiment shown, the control groove 22 is formed in the sealing face 20, e.g. as a partially cylindrical milled-out portion. The nozzle D formed by the control groove 22 at the closed position defines, in the flow direction R, a constriction and increases in width subsequently.

[0038] The valve cone 18 is arranged on a stem 23, which is connected to a piston 25 of a drive 14 and which is adapted to be acted upon by a pressure fluid in a chamber 27, so as to adjust the closed position shown in FIG. 1. In the opposite direction, a spring 26 is effective, said spring 26 adjusting an open position of the steam trap A (FIG. 6). The stem 23 is sealed off from the valve chamber 17 by means of a seal 24.

[0039] In the case of an alternative, which is not shown, the control groove 22 may be arranged in the seating area 21 of the seat 19, or circumferentially aligned control grooves may be provided in the seating area 21 as well as in the sealing face 20. Furthermore, a plurality of control grooves 22, which are distributed in the circumferential direction, may be provided.

[0040] The inlet 12 is configured as a cylindrical extension 28 of the small-diameter end of the seat 19 and such that it has the diameter of the latter and it forms, together with an annular flange 30 provided on the end of the valve cone 18, a circumferentially extending annular gap P of constant width (e.g. from 0.2 up to 0.4 mm) at the closed position shown, said annular gap P being only formed as long as the small-diameter end of the valve cone 18 with the annular flange 30 extends into the cylindrical extension 28 during the opening and closing switching movements of the valve cone 18. The valve cone 18 has formed therein, adjacent to the annular gap P when seen in the flow direction R, an annular flow space 31, e.g. a circumferential groove 32 (FIG. 2), which extends substantially parallel to the annular gap P and in which the nozzle D begins.

[0041] The steam trap A with the annular gap P may also be operated without the control groove 22.

[0042] In the embodiment according to FIGS. 1 and 2, the seat 19 and the valve cone have different taper angles, i.e. the taper angle of the sealing face 20 of the valve cone 18 is smaller by an angle a than the taper angle of the seating area 21 of the seat 19. The difference between these angles may range from approx. 1 to 4. This has the effect that, when the sealing face 20 at the small-diameter end of the valve cone 18 abuts on the seating area 21 at the small-diameter end of the seat 19, an open space will be created in the flow direction R, into which the nozzle D opens, said nozzle D extending, according to FIG. 3, only from an edge 33 of the circumferential groove 32 over part of the axial height of the sealing face 20. The nozzle D has a cross-section which first narrows in the flow direction R and it increases in width, e.g. with the open space, from the narrowest point onwards.

[0043] According to an alternative embodiment, which is not shown, the taper angles of the valve cone 18 and of the seat 19 may be identical. In this case, the control groove 22 (in the sealing face 20 or in the seating area 21 or in both said components) extends up to the large-diameter end of the sealing face 20 or of the seating area 21. The respective taper angle may be between approx. 30 and 60, and is optionally an angle of approx. 40 (tip angle).

[0044] The annular gap P is delimited by the annular flange 30 at the small-diameter end of the valve cone 18 and by the inner wall of the cylindrical extension 28. The annular flange 30 may be undercut by the circumferential groove 32, contours having a rounded cross-section and a rounded transition being here expedient. At the closed position shown in FIGS. 1 and 2, the edge 33 of the circumferential groove 32 is located approximately on the level of the small-diameter end 29 of the seating area 21 of the seat 19. The nozzle D has, at the closed position, a radial width Y that is larger than the width X of the annular gap P.

[0045] In FIG. 3 only one control groove 22 is shown on the valve cone 18 at a circumferential position. Alternatively, more than one control groove may be distributed in the circumferential direction.

[0046] FIG. 4 shows the steam trap A at a position corresponding to the beginning of a final phase of a closing switching movement of the valve cone 18, i.e. a flow through the annular gap P is possible, which serves to flush the valve seat before the valve seat is finally closed. This flowthrough is much higher than the flowthrough at the closed position in FIG. 1, but much lower than the flowthrough at the open position in FIG. 6.

[0047] In the case of a further alternative, which is not shown, the control groove 22 may be omitted, so that the annular gap P alone determines the flowthrough between the positions according to FIG. 1 and FIG. 4.

[0048] FIG. 5 illustrates, on an enlarged scale, a detail emphasized in FIG. 4 by a circle. The annular flange 30, which delimits the annular gap P with the cylindrical extension 28 and the width X, is located approximately on the level of the small-diameter end 29 of the seat 19, whereas the circumferential groove 32 is located below the small-diameter end 29. The control groove 22 is, in the sealing face 20, already located at a considerable distance Y1 from the seating area 21, said distance Y1 being a multiple of the width X, e.g. twelve times the width X.

[0049] At the open position of the steam trap A shown in FIG. 6 and switched by the spring 26, the valve cone 18 has been pulled out of the seat 19 approximately down to the large-diameter end of the seat 19, so that a large flow cross-section corresponding approximately to the cross-sections of the cylindrical extension 28 and of the outlet 13 is open.

[0050] The annular gap P serves a dual purpose: at the closed position according to FIG. 1, the annular gap P prevents particles contained in the condensate/steam and having a size larger than the width X of the annular gap P from entering the nozzle D and the seat 19, respectively. In this way, clogging of the nozzle D will be prevented. In the final phase of the closing switching movement of the valve cone (between FIG. 5 and FIG. 2), the annular gap P prevents larger particles from penetrating between the sealing face 20 and the seating area 21, where they might get stuck and obstruct or prevent the reaching of the closed position according to FIG. 1 and clog the nozzle D. The flow passing through the annular gap P flows into the circumferential groove 32 from all sides and from said circumferential groove 32 to the nozzle D and the outlet 13.

[0051] Since the circumferential length of the annular gap P is a multiple of the nozzle width, many particles can accumulate along the annular gap P before the annular gap P will be blocked completely. When the opening switching movement of the valve cone 18 has started and when the annular flange 30 is being pulled out of the seat 19, a large flow cross-section will open, so that fast flowing condensate will intensively clean the nozzle D and the control groove 22 (if there is one), the seating area 21 and the sealing face 20. In the case of clogging, a controlled intermediate cleaning step may be carried out, e.g. by pulling the valve cone 18 towards the position according to FIG. 6 for a short period of time, and, when contaminations have been flushed out, by returning the valve cone 18 to the closed position or the position according to FIG. 4. During the closing switching movement of the valve cone 18, the annular gap P prevents larger particles from getting stuck in the seat 19, since the annular gap P already becomes effective before the valve cone 18 enters into contact with the seat 19 and since, in this phase, the space between the valve cone 18 and the seat 19 is still large enough for discharging penetrating particles having a size larger than the width X of the annular gap P outwards to the outlet 13.

[0052] The closed position shown in FIG. 1 is switched, e.g. during a sterilization cycle with steam, e.g. in the leakage chamber 9 of the double seat valve 1, whereas the open position shown in FIG. 6 belongs to a flushing cycle in the course of which the leakage chamber 9 is cleaned with liquid condensate or with a mixture of condensate and steam.