Gate valve

Abstract

A gate valve comprising a valve housing with connection openings disposed in mutually opposite relationship on a first common axis, and also connection elements for the inlet and outlet of a fluid, a cap on the valve housing and a valve actuation means coupled to a sliding gate. It is provided therein that arranged in the valve housing are: a hollow cage having a first and a second end face of which the first end face has an insertion opening, further with two mutually oppositely disposed fixed side walls and two parallel mutually oppositely disposed free side walls which are formed by two separate side plates with through bores which in the installed condition are on a second common axis, the sliding gate which has a through-flow opening is introduced through the insertion opening of the cage and is guided sealingly in the cage and between the side plates and the side plates bear with their respective inward side in surface contact against the sliding gate, the sliding gate has two end positions so that in a first opened end position the through-flow opening of the sliding gate coincides completely with the diameter of the through bores of the side plates in the installed condition and in a second closed end position the through-flow opening of the sliding gate is completely outside the diameter of the through bores of the side plates.

Description

The invention concerns a gate valve comprising a valve housing with connection openings disposed in mutually opposite relationship on a first common axis, and also connection elements for the inlet and outlet of a fluid, a cap on the valve housing and a valve actuation means coupled to a sliding gate.

Gate valves are known in many different configurations. Conventional shallow-wedge sliding gates have a wedge-shaped shut-off member which when the valve is closed is pressed into a wedge-shaped receiving means. In that case the degree of sealing integrity is dependent on the contact pressure. When the valve is opened, deposits, so-called incrustations, are formed, which accumulate when the wedge member is closed and are pressed into the wedge-shaped receiving means. The result of this can be that the valve must firstly be closed with a greater contact pressure and also that it no longer closes completely at all.

In the present case the object is to provide a gate valve in which deposits forming from the flow of fluid in the valve no longer collect in the valve housing and can no longer adversely affect the closing function of the valve.

That object is attained in that arranged in the valve housing are a hollow cage having a first and a second end face of which the first end face has an insertion opening, further with two mutually oppositely disposed fixed side walls and two parallel mutually oppositely disposed free side walls which are formed by two separate side plates with through bores which in the installed condition are on a second common axis, that the sliding gate which has a through-flow opening is introduced through the insertion opening of the cage and is guided sealingly in the cage and between the side plates and the side plates bear with their respective inward side in surface contact against the sliding gate, that the sliding gate has two end positions so that in a first opened end position the through-flow opening of the sliding gate coincides substantially or completely with the diameter of the through bores of the side plates in the installed condition and in a second closed end position the through-flow opening of the sliding gate is completely outside the diameter of the through bores of the side plates. Advantageous developments are described in the appendant claims.

In that respect it is preferred for the side plates and the sliding gate to comprise ceramic, the cage to comprise a plastic material and the valve housing, the connection elements and the cap to comprise cast metal or to be hot-pressed or forged. The fact that the side plates are mounted in a plastic cage makes it possible to guarantee precise positioning of the ceramic plates relative to each other.

It is further preferred that the second end face of the cage has a cylindrical concave curvature and the curvature forms the connection of the fixed side walls. Preferably at their one end the side plates follow the contour of the curvature and are inserted into the free side walls of the cage.

In addition the side plates are preferably of a mirror-image configuration and the first common axis of the mutually oppositely disposed connection openings, in the installed condition, coincides with the second common axis of the through bores in the separate side plates.

In a preferred embodiment each of the side plates has a projection in the form of a rib which extends around the through bore and which engages into the connection openings of the valve housing or into the connection elements disposed therein. The engagement of the separate side plates into the connection openings of the valve housing or into the connection elements disposed therein is preferably sealed off by means of flat seals and/or O-rings. In that way, a slight prestressing can be produced on the ceramic plates by means of the flat seals while the O-rings provide for static sealing integrity.

Preferably the sliding gate has an abutment element for limiting the movement of the sliding gate. In a preferred configuration the abutment element is a transverse bar which comprises cast metal or is hot-pressed or forged and which is pushed through a transverse opening in the sliding gate and held there. Precise stroke movement limitation is possible by means of the transverse bar.

In a preferred embodiment, in the first opened end position of the sliding gate an abutment for the movement of the sliding gate is formed by a projection in the cap, against which projection the transverse bar bears, and in the second closed end position of the sliding gate a further abutment for the movement of the sliding gate is formed by the exposed upper face of the valve housing, against which the transverse bar bears.

In a further preferred configuration, in the first opened end position of the sliding gate an abutment for the movement of the sliding gate is formed by abutment pins which are screwed into the transverse bar and which butt against the exposed upper face of the valve housing and in the second closed end position of the sliding gate a further abutment for the movement of the sliding gate is formed by a projection in the cap, against which projection the transverse bar bears.

Preferably at least one of the side plates on the side that is towards the sliding gate has a passage which with its one end opens into the respective through bore in the side plate and which in the second closed end position of the sliding gate opens with its other end in the through-flow opening in the sliding gate.

The valve actuation means preferably has a spindle which engages into the transverse bar and the sliding gate preferably has a blind bore for receiving the spindle. The spindle is preferably a screwthreaded spindle which is held axially immovably in a bearing in the cap and which is screwed with a screwthreaded portion into the transverse bar. The gap between the spindle and the bearing in the cap is preferably sealed off by means of an O-ring.

That structure provides for better long-term sealing integrity. In addition that structure makes it possible to use the advantages of ceramic materials such as for example resistance to corrosion, a small amount of wear and low weight insofar as it permits a simple connection of the spindle to the ceramic sliding gate and an exact position for the end positions of the valve. In addition the component parts are easy to produce and by virtue of simplicity of structure are suitable for machining by automatic equipment. That additionally affords cost advantages in terms of manufacture.

The invention however not only attains that object but also has further advantages. Thus, even after a long period of no use, the closing forces of the valve are low in contrast to conventional valves which, by virtue of corrosion, are difficult to move after a prolonged period of not being used. The preferred configuration with a passage in the inside surface of a side plate also affords the advantage that the valve is dead water-free and frost-resistant if the passage is on the discharge flow side of the valve and the connection region is beneath the through-flow opening so that the fluid can flow away out of the through-flow opening.

The invention is described in greater detail hereinafter by means of embodiments and with reference to the drawings in which:

FIG. 1 shows an exploded view of a valve in a first embodiment,

FIG. 2a shows a view in longitudinal section through a valve of the first embodiment in the opened position,

FIG. 2b shows a view in longitudinal section turned through 90° through the valve of FIG. 2a,

FIG. 3 shows an exploded view of a valve in a second embodiment,

FIG. 4a shows a view in longitudinal section corresponding to FIG. 2a of the second embodiment,

FIG. 4b shows a view in longitudinal section turned through 90° through the valve of FIG. 4a,

FIG. 5a shows a view in longitudinal section corresponding to FIG. 4a through the valve in the closed position, and

FIG. 5b shows a view in longitudinal section corresponding to FIG. 4b through the valve in the closed position.

In the description hereinafter of the embodiments by way of example, terms such as ‘left’, ‘right’, ‘top’, ‘bottom’, ‘inner’, ‘outer’, ‘vertical’ or ‘horizontal’ relate to the illustration of the valve in the accompanying drawings. The choice of those terms serves solely to facilitate the present description and under no circumstances is to be interpreted as limiting the scope of protection for the described valves can be installed in any spatial position.

The component parts of the valve will firstly be described by reference to the embodiments by way of example. Components involving the same function are referenced in the same manner in the Figures.

The valve which is intended in particular for liquids has a valve housing 10, connection elements 12, 14 for the inlet and outlet, a cap 16 on the valve housing 10 and a valve spindle 22 which is rotatable by an actuation element, for example a hand wheel 18, about a vertical axis 20. In the illustrated embodiment the connection elements 12, 14 are arranged on a common horizontal axis 24. Arranged within the valve housing are a cage 26, two side plates 28, 30 to the right and the left of the cage 26, a sliding gate 32 between the side plates 28, 30 and a transverse bar 34 in the sliding gate 32.

The valve housing 10 which comprises cast metal or is hot-pressed or forged has four side faces, comprising two mutually opposite closed side faces 36, 38 and two further mutually opposite side faces 40, 42, an upper opening 44 and a lower end face with a cylindrical concave curvature 46 which connects the closed side faces 36, 38. The further side faces 40, 42 each have a respective connection opening 48, 50 with a female screwthread, into which are screwed the connection elements 12, 14 which are provided with a male screwthread. Adjoining the side faces 36, 38, 40, 42 upwardly is an exposed face 52 in substantially perpendicular relationship to the side faces 36, 38, 40, 42, which at its outside goes into an upstanding flange 54 with a female screwthread 56.

The cap 16 which also comprises cast metal or can be hot-pressed or forged, in the lower region thereof, has a diameter and a male screwthread 58 which match the upstanding flange 54 of the valve housing 10. In the illustrated embodiments the two are screwed there. At a predetermined height the diameter of the cap 16 decreases so that a projection 60 is formed in the interior of the cap 16. Above the projection 60 the diameter further reduces to an upper bore 62. The outside wall of the cap 16 is of a hexagonal configuration in the region of the upper bore 62 so that it can be screwed to the valve housing 10 by means of a screw wrench.

The spindle 22 which also comprises cast metal or is hot-pressed or forged includes, viewed from below upwardly, a screwthreaded portion 64, an annular flange 66, a cylindrical sealing portion 68 with a groove 70, a further screwthreaded region 72 and a connection portion 74 which from its free end is at least partially provided with a screwthread 76. The annular flange 66 prevents a movement of the spindle 22 which is guided from below through the bore 62 upwardly out of the cap 16. A movement of the spindle 22 downwardly out of the cap 16 is prevented by a nut 78 which is screwed on to the screwthreaded region 72. The sealing portion 68 is thus axially immovably guided in the bore 62 of the cap 16. An O-ring 80 is arranged in the groove 70 for affording sealing integrity.

To rotate the spindle 22, in the illustrated embodiment a hand wheel 18 is fitted from above on to the spindle and fixed with a nut 82 which is screwed on to the screwthread 76.

The hollow cage 26 comprises plastic material and in the first embodiment in the installed condition terminates below the exposed surface 52 of the valve housing 10. In the second embodiment the cage 26, in the installed condition, projects into the cap 16, but no further than the length of the abutment pins 120, 122 which are described hereinafter in the second embodiment. The cage 26 has two end faces of which the upper end face has an insertion opening 84 and the lower end face has a cylindrical concave curvature 86. In addition the cage 26 has two mutually opposite fixed side walls which are connected by the curvature 86. In addition the cage 26 includes two parallel, mutually opposite free side walls which are at least partially formed by two separate side plates 28, 30.

The side plates 28, 30 comprise ceramic material and in the first embodiment are completely of the same contour as the free side walls of the cage 26. In the second embodiment the side plates 28, 30 are not completely of the same contour as the free side walls of the cage but in the installed condition terminate beneath the connection openings 48, 50 of the valve housing 10.

The side plates 28, 30 are inserted into the free side walls of the cage from the side. Their mutually opposite flat faces are ground and polished. In addition the side plates 28, 30 are of a mirror-image configuration and each have a respective through bore 88, 90 with a horizontal axis 92 which is common in the installed condition. Each of the side plates 28, 30 has a projection 94, 96 in the form of a rib which extends around the through bore 88, 90.

The sliding gate 32 which also comprises ceramic material is of an elongate, plate-shaped configuration and has two spaced, parallel and flat side faces 98, 100 which are ground and polished. The side faces 98, 100 contact in sealing relationship the surfaces of the side plates 28, 30, which are in opposite relationship in the cage 26. In other respects the sliding gate 32 is matched to the internal contours of the cage 26. The sliding gate 32 also has a through-flow opening 102 which extends between the side faces and whose shape and diameter corresponds to the through bores 88, 90 in the side plates 28, 30. In the upper region the sliding gate 32 has a transverse opening 104 for receiving the transverse bar 34 and a blind bore 106 for receiving the spindle 22.

The transverse bar 34 which comprises cast metal or can be hot-pressed or forged is of a quadrangular cross-section in the illustrated embodiment, with a central portion 108 which is approximately square in cross-section, and two flattened ends 110, 112. The cross-section of the central portion 108 is matched to the cross-section of the transverse opening 104 in the sliding gate 32. In addition, in its central portion 108, the transverse bar 34 has a perpendicular screwthreaded bore 114. In a second embodiment (FIGS. 3 to 5) the transverse bar 34 additionally has in each of its ends 110, 112 a screwthreaded bore 116, 118 which is parallel to the screwthreaded bore 114.

Furthermore the second embodiment additionally has cylindrical abutment pins 120, 122 in perpendicular relationship with the exposed upper face 52 of the valve housing 10. At their upper ends the abutment pins 120, 122 have a male screwthread with which they are screwed into the screwthreaded bores 116, 118 of the transverse bar 34.

In addition, in the second embodiment, one of the side plates 28, 30, in its surface which is towards the sliding gate 32, additionally has a passage 124 in the form of a groove which opens with its one end into the through bore 88, 90 in the side plate 30 and which extends from the mouth opening location in the direction of movement of the sliding gate 32 into a region of the side plate 30 which, when the valve is closed, is disposed where the through-flow opening 102 of the sliding gate 32 is to be found.

The mode of operation of the valve will now be described by reference to the embodiments.

The cage 26 and the side plates 28, 30 which are inserted into its free side walls are arranged within the valve housing 10 in such a way that the horizontal axis 92, which is common in the installed condition, of the through bores 88, 90 of the side plates 28, 30 coincides in the installed condition with the horizontal axis 24 of the connection elements 12, 14 and the connection openings 48, 50. The projection 94, 96 of each of the side plates 28, 30 engages into the connection elements 12, 14 and sealing integrity of the connection between the side plates 28, 30 and the connection elements 12, 14 is ensured by means of flat seals 126, 128 and O-rings 130, 132. In an embodiment not illustrated here it is possible to use flat seals or O-rings.

The sliding gate 32 is introduced into the cage 26 through the insertion opening 84 thereof and is guided between the fixed side walls of the cage 26 and the side plates 28, 30 in surface contact relationship bearing sealingly thereagainst.

The transverse bar 34 is pushed through the transverse opening 104 in the sliding gate 32 and held there so that the screwthreaded bore 114 in the central portion 108 of the transverse bar 34 is on an axis with the blind bore 106 of the sliding gate 32 for receiving the spindle 22. The spindle 22 engages with its screwthreaded portion 64 into the screwthreaded bore 114 of the transverse bar 34.

Rotation of the axially immovable spindle 22 causes the transverse bar 34 to move up and down on the screwthreaded portion 64 of the spindle 22, entraining the sliding gate 32. In that way the sliding gate 32 can now be moved up and down. The movement of the sliding gate 32 is limited by two end positions which are established by abutments. In a first opened end position the through-flow opening 102 of the sliding gate 32 is completely aligned with the through bores 88, 90 in the side plates 28, 30. In a second closed end position the through-flow opening 102 of the sliding gate 32 is disposed completely outside the region of the through bores 88, 90 in the side plates 28, 30.

In the first embodiment the first opened end position of the sliding gate 32 (FIG. 2) is established by the transverse bar 34 bearing against the projection 60 in the cap 16. The second closed end position of the sliding gate 32 is defined in the first embodiment by the transverse bar 34 bearing against the exposed upper face 52 of the valve housing 10.

In the second embodiment the first opened end position of the sliding gate 32 (FIG. 4) is established by the abutment pins 120, 122 which are screwed into the transverse bar 34 butting against the exposed upper face 52 of the valve housing 10. The second closed end position of the sliding gate 32 (FIG. 5) is defined in the second embodiment by the transverse bar 34 bearing against the projection 60 in the cap 16.

In the second embodiment the valve is therefore closed when the transverse bar 34 bears against the upper abutment 60. In that position the above-mentioned passage 124 communicates the dead space of the through-flow opening 102 of the sliding gate 32 with one of the connection regions (through bore 88, 90 and connection elements 12, 14) of the valve. Assuming that the passage 124 is disposed on the discharge flow side of the valve and the connection region is below the through-flow opening 102 the fluid can flow away out of the through-flow opening 102. Dead water in the valve and the risk of frost are avoided thereby.

As explained hereinbefore these are possible forms of implementation but are not restricted thereto.

The invention therefore achieved the provision of a valve which can be produced inexpensively and automatically, which is corrosion-resistant and thus easily operable even after a long period of not being used and is possibly dead water-free and frost-resistant and has precise stroke movement limitation.

Claims

1. A gate valve comprising a valve housing with connection openings disposed in mutually opposite relationship on a first common axis, and also connection elements for the inlet and outlet of a fluid, a cap on the valve housing and a valve actuation means coupled to a sliding gate, wherein arranged in the valve housing are a hollow cage having a first and a second end face of which the first end face has an insertion opening, further with two mutually oppositely disposed fixed side walls and two parallel mutually oppositely disposed free side walls which are formed by two separate side plates with through bores which in the installed condition are on a second common axis, that the sliding gate which has a through-flow opening is introduced through the insertion opening of the cage and is guided sealingly in the cage and between the side plates and the side plates bear with their respective inward side in surface contact against the sliding gate, that the sliding gate has two end positions so that in a first opened end position the through-flow opening of the sliding gate coincides substantially or completely with the diameter of the through bores of the side plates in the installed condition and in a second closed end position the through-flow opening of the sliding gate is completely outside the diameter of the through bores of the side plates.

2. A gate valve according to claim 1 characterised in that the side plates and the sliding gate comprise ceramic and the mutually touching surfaces thereof are polished.

3. A gate valve according to claim 1, wherein that the cage comprises a plastic material.

4. A gate valve according to claim 1, wherein the valve housing, the connection elements and the cap comprise cast metal or are hot-pressed or forged.

5. A gate valve according to claim 1, wherein the second end face of the cage has a cylindrical concave curvature and the curvature forms the connection of the fixed side walls.

6. A gate valve according to claim 5 wherein at one end, the side plates follow the contour of the curvature.

7. A gate valve according to claim 1, wherein the separate side plates are inserted into the free side walls of the cage.

8. A gate valve according to claim 1, wherein the side plates are of a mirror-image configuration and the first common axis of the mutually oppositely disposed connection openings, in the installed condition, coincides with the second common axis of the through bores in the separate side plates.

9. A gate valve according to claim 1, wherein each separate side plate has a projection in the form of a rib which extends around the through bore and which engages into the connection openings of the valve housing or into the connection elements disposed therein.

10. A gate valve according to claim 1, wherein the engagement of the separate side plates into the connection openings of the valve housing or into the connection elements disposed therein is sealed off by flat seals and/or O-rings.

11. A gate valve according to claim 1, wherein the sliding gate has an abutment element for limiting the movement of the sliding gate.

12. A gate valve according to claim 11 wherein the abutment element is a transverse bar which is pushed through a transverse opening in the sliding gate and held there.

13. A gate valve according to claim 11 wherein transverse bar comprises cast metal or is hot-pressed or forged.

14. A gate valve at least according to claim 13 wherein the first opened end position of the sliding gate an abutment for the movement of the sliding gate is formed by a projection in the cap, against which projection the transverse bar bears, and in the second closed end position of the sliding gate a further abutment for the movement of the sliding gate is formed by the exposed upper face of the valve housing, against which the transverse bar bears.

15. A gate valve at least according to claim 13 wherein at the first opened end position of the sliding gate an abutment for the movement of the sliding gate is formed by abutment pins which are screwed into the transverse bar and which butt against the exposed upper face of the valve housing and in the second closed end position of the sliding gate a further abutment for the movement of the sliding gate is formed by a projection in the cap, against which projection the transverse bar bears.

16. A gate valve at least according to claim 15 wherein at least one of the side plates on the side that is towards the sliding gate has a passage which with its one end opens into the respective through bore in the side plate and which in the second closed end position of the sliding gate opens with its other end in the through-flow opening in the sliding gate.

17. A gate valve at least according to claim 1 wherein the valve actuation means has a spindle, wherein the spindle engages into the transverse bar and the sliding gate has a blind bore for receiving the spindle.

18. A gate valve according to claim 17 wherein the spindle is a screwthreaded spindle and is held axially immovably in a bearing in the cap and a screwthreaded portion of the spindle is screwed into the transverse bar.

19. A gate valve according to claim 1 wherein the gap between the spindle and the bearing in the cap is sealed off by an O-ring.