AU3677599A

AU3677599A - Slide valve assembly

Info

Publication number: AU3677599A
Application number: AU36775/99A
Authority: AU
Original assignee: STABLE AUSTRALIA Pty Ltd
Current assignee: STABLE AUSTRALIA Pty Ltd
Priority date: 1998-06-26
Filing date: 1999-06-25
Publication date: 2000-01-13

Description

I

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): STABLE AUSTRALIA PTY LTD Invention Title: SLIDE VALVE ASSEMBLY *r

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VV V V V The following statement is a full description of this invention, including the best method of performing it known to me/us: 1 II _L 2 SLIDE VALVE ASSEMBLY This invention relates to a slide valve assembly, in particular for, but not exclusively for, controlling flow of dust from chimneys or stacks in power generation plants.

However, it should be noted that the valve arrangement could be used in other environments for the control of flow of material.

In power generation plants, particularly those which are coal powered, dust and solid residue created by flue gasses collect in chimneys and stacks within the power plant. The dust and solid residue created by flue gasses eventually drop to the bottom of boiler precipitator hoppers and are conveyed away from the hoppers for disposal. The conveyed dust is passed through a chute. It is desirable to control the flow of the dust through the chute so that the flow can be shut off or opened as is required.

Some valve arrangements have been proposed for controlling the flow of dust through the chute with varying degrees of success.

The present invention has for its object a valve arrangement which can be used to control the flow of dust in such environments but which also could be used in the other environments for controlling flow of material (such as cement or grain).

The invention may be said to reside in a slide valve assembly, including: a housing defining a passage for the flow of material; coupling portions on the housing for coupling the housing to a chute so that the material can flow through the chute and passage; H: \paula\Keep\speci\STABLE-slide-valve-assembly.doc 25/06/99 I 3 a gate valve element for sliding movement from an open position in which the passage is open to allow for flow of the material through the chute and passage and a closed position in which the gate valve closes the passage to the flow of the material; drive means for driving the gate valve between the open and closed positions; a first seal arrangement on one side of the housing and a second seal arrangement on an opposed side of the housing; and a first slot through the housing and the first seal arrangement through which the gate valve element moves during movement between the open and closed positions and a second slot in the second seal arrangement for at least receiving the gate valve element so that when the gate valve is in the opened position a first portion of the gate valve is received by the first seal arrangement, and wherein when the gate valve is in the closed position other portions of the gate valve are received by the first and second seal arrangements to thereby seal the gate valve and the passage so that in both the open and closed positions, the housing and passage are sealed so that dust flowing through the chute cannot exit the valve assembly through the slots.

Since the gate valve is sealed regardless of the position of the gate valve, dust which flows through the valve does not escape from the valve arrangement other than by flowing through the passage and therefore during flow of material or stoppage of flow of material dust cannot escape into the surrounding environment from the valve arrangement.

In the-preferred embodiment of the invention, the second slot extends through the housing and the second seal arrangement so that the gate valve passes through the second slot, the gate valve having an opening which, when the gate valve is in the closed position, registers with H: \paulad\Keep\speci\STABLE-slide-valve-assembly.doc 25/06/99

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-4 the passage with a second portion of the gate valve being arranged within the second slot of the housing and the second seal arrangement, and during movement to the closed position, the gate valve slides through the first slot in the housing and the first seal arrangement and also the second slot in the housing and second valve arrangement.

Thus, in this embodiment of the invention, a portion of the gate valve is always received in the first and second seal arrangements regardless of the position of the gate valve.

This allows movement of the gate valve and also prevents dust from building up within the seals and slots which might inhibit movement of the gate valve and prevent complete closing or opening of the gate valve.

Preferably, the drive means comprises a pair of hydraulic or pneumatic rams having ram arms coupled to the gate valve for moving the gate valve between the open and closed positions.

Preferably the first and second seals each comprise a stuffing box and a gland follower defining a cavity, the first and second slots passing through the respective stuffing boxes and gland followers, and the cavity receiving packing material so that the packing material seals against the gate valve when the gate valve is in both the open and closed positions.

Preferably the coupling portions of the housing comprise first flanges on a top end of the housing and second flanges on a bottom end of the housing.

Preferably guard assemblies are provided on opposed sides of the housing for guarding the gate valve when the gate valve is in both an open and closed position to prevent injury to a person during movement of the gate valve from the open to the closed position.

H: \paulad\ Keep\ speci \STABLE- slide -valve- assembly. doc 25/06/99 5 Preferably the stuffing boxes and gland follower are coupled together by retaining bolts.

A preferred embodiment of the invention will be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view in plan of the valve assembly according to one embodiment of the invention; Figure 2 is a side cross-sectional view of the valve of Figure 1; Figure 3 is a detailed view of part of the assembly shown in Figure 2; and Figures 4, 5 and 6 are views of parts of the valve assembly of Figures 1, 2 and 3.

With reference to the drawings, a valve arrangement 10 is shown which has a housing 20 of generally square configuration as clearly shown in Figure 1. The housing has four sides 22, 24, 26 and 28 which define a passage Each of the sides 22 to 28 have flanges 30 at a top and bottom end which have a plurality of holes 32 for enabling the housing 20 to be bolted to a chute (not shown) through which material is to be transferred.

The valve assembly 10 has a rear guard frame 40 having a back wall 42, an upper wall 44, a lower wall 46 and side walls 48. The walls 42 to 48 may be formed by guard panels such as the panel 46 most clearly seen in Figure 1 so as to define a rear guard box the purpose of which will be defined in more detail hereinafter.

A front guard frame 50 is provided on the opposed side of the housing 20 and comprises upper wall 52, end wall 54, lower wall 56 and side walls 58. Once again, the walls 52 to 58 can be completed by guard panels, such as the panel 56 shown in Figure 1 to define a front guard box.

H: \paulad\Keep\speci\STABLE-Slide-valve-asseUblY.doc 25/06/99 6 A pair of rear ram support flanges 60 are connected to the side walls 46 and a pair of front ram support flanges 62 which are a continuation of the side wall 22 of the housing 20. Hydraulic or pneumatic ram cylinders 64 are connected between the respective flanges 60 and 62 by nuts and bolts 63. The ram 64 can be connected to the flanges 60 and 62 by cylinder end housing 65 which are secured to the ram 64 and receives the bolt 63 for coupling the ram 64 to the flanges 60 and 62.

The ram cylinders 64 have ram piston rods 66 which in the position shown in Figure 2 are projecting out of the cylinders 64. The piston rods 66 have clevises 67.

A gate valve plate 80 is located within the assembly and has flanges 82 at one end which are received within the clevises 67 and can be secured to the clevises 67 and therefore the piston rods 66 by bolts (not shown).

As best shown in Figure 4, the valve plate gate 80 has a square-shaped aperture 84 at one end. The aperture 84 is surrounded by edge portions 86 of the plate 80 and an end portion 88. The other side of the aperture 84 is defined by peripheral portion 89 of the plate 80. The gate 80 also has a closure section A seal 92 is arranged on each of the sides 22 and 26 and the two seals 92 are a mirror image of one another. The seals 92 will be described in more detail with reference to Figure 3 which shows the seal 92 on the side 26.

The seal 92 shown in Figure 3 include a stuffing box 94 arranged on the outer side of the wall 26. A gland follower 98 is provided on the stuffing box 94. As clearly shown in Figure 3, the stuffing box 94 has a generally Cshaped cross-section and includes a pair of projecting H: \paulad\Keep\speci\STA.BLE-slide-valve-assenblY.doc 25/06/99 8- 7 portions 94a. The gland follower 98 has a central projection 98a which is received between the projections 94a and a cavity 104 is defined between the stuffing box portion 94a and gland cover portion 98a in which is received upper and lower packings 106 which form a seal against the valve plate The opposed sides 22 and 26 and the seals 92 each have a slot 91 passing therethrough. The slot 91 comprises a slot 90 in the sides 22 and 26 of the housing 20 and aligned slots 96 and 100 in the stuffing boxes 94 and gland followers 98 respectively. As best shown in Figure 5, the stuffing box has large openings 101 which have enlarged diameter head portions 101' (see Figure 3) for receiving socket head cap screws (not shown) for coupling the stuffing box to the wall 26. The wall 26 may also have projecting studs 105 (see Figure 2) which pass through small openings 110 in the stuffing box. The gland follower 98 has openings 113 which align with the openings 110 and receive the studs 105. Nuts 102 are screwed onto the studs 105 to thereby secure the gland follower 98 onto the stuffing box 94.

As is best shown in Figure 3, the slide gate 80 is received through the slots 91 in the sides 22 and 26 respective seals 92 so the packings 106 forms a seal onto the slide plate 80 for sealing the slide plate 80 so that material to pass through the valve assembly will not escape through the slots 91.

The opposed sides 24 and 28 of the housing 20 can each carry a pair of guide rails 110, 112 for guiding movement of the plate 80 between an open and closed position which will be described in more detail hereinafter. The rails 110 and 112 receive edges 81 of the plate H: \Paulad\Keep\speci\STABLE-slide-valve-assemblydoc 25/06/99 8 In the position shown in Figure 1, the aperture 84 of the plate 80 is aligned with passage 25 defined by the housing and, in particular, by the side walls 22, 24, 26 and 28 of the housing 20 so that material can pass through the valve assembly 10 in the position shown in Figure 1. In order to close the valve assembly, the rams 64 are actuated to retract the piston rods 66 so that the rods 66 and therefore the valve plate 80 moves in the direction of arrow A in Figure i. This will move the plate 80 through the seals 92 formed by the stuffing boxes 94, packings 106 and gland followers 98 so that the plate 80 moves into the rear guard frame 40. Movement of the plate is protected by the guard frame 40 so it is not possible for a workman to locate themself in the path of the moving gate 80. The gate 80, when in the fully retracted position, closes off the passage through the housing 20 by the closure portion of the gate 80 registering with the passage 25 through the housing 20. Thus, flow of material through the valve assembly is therefore stopped. Movement of the plate 80 in the direction of arrow A is guided by the guide rails 110 and 112 and the seals 92.

In the fully opened position shown in Figure 1, the slots 91 are sealed by the positioning of the peripheral portion 88 of the plate 80 within the seal 92 on the side 26 and the peripheral portion 89 within the seal 92 on the side 22. Thus, when material flows through the valve, material does not escape through the slots 91. When the plate moves to the closed position, the peripheral portion 89 locates within the seal 92 on the side 26 and portion 97 (shown in Figure 4) locates within the seal 92 on the side 22 so that in the closed position the slots 91 are also sealed so that material which is stopped from flowing through the valve arrangement also cannot escape through the slots 91. The location of the peripheral portions 88, 89 and the portion 97 of the plate 80 described above engage with the packing material 106 so as to form the seal H: \paulad\Keep\speci\STALE-slide-valve-assemblydoc 2/06/99 9 and prevent the egress of material through the sides 22 and 26 in both the open and closed position of the valve arrangement.

When it is desired to open the valve, the rams 64 are actuated to drive the piston rods 66 in a direction opposite arrow A so that the gate 80 is moved to the left in Figure 1 with the main portion being accommodated within the front frame assembly 50 until the opening 84 registers with the passage 25 through the housing Once again, movement of the plate 80 is guarded by the front guard frame 50 so that a workman will not be contacted by the moving plate The fact that the valve plate 80 passes through both slots 91 during both the open and closed position of the valve plate 80 ensures that dust and other material does not build up within the slots 91 which may otherwise prevent proper operation and, in particular, proper closing of the valve plate 80. During the open position, the closure plate 80 is received within the slot 91 of the seal 92 associated with side 22 and during closing movement, the closure portion 85 passes through that slot 91 so material cannot build up in the slot. As the portion 88 leaves the slot 91 associated with the seal 92 on side 26, the slot 92 will be partially opened to material but when the portion 89 enters that slot to completely close off the valve arrangement, any slight buildup of dust in the slot 91 during the closing movement will be pushed out of the slot as the portion 89 of the plate 80 enters that slot.

Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not H:\paulad\Keep\speci\STABLE-side-vave-assembly.doc 25/06/99 10 limited to the particular embodiments described by way of example hereinabove.

H: \paulad\Keep\speci\STABLE-slide-valve-assembly.doc 25/06/99

Claims

2. The valve assembly of claim 1 wherein, the second slot extends through the housing and the second seal arrangement so that the gate valve passes through the second slot, the gate valve having an opening which, when H: \paulad\Keep\speci\STABLE-slide-valve-assemblydoc 25/06/99 12 the gate valve is in the closed position, registers with the passage with a second portion of the gate valve being arranged within the second slot of the housing and the second seal arrangement, and during movement to the closed position, the gate valve slides through the first slot in the housing and the first seal arrangement and also the second slot in the housing and second valve arrangement.
3. The valve assembly of claim 1 or 2 wherein, the drive means comprises a pair of hydraulic or pneumatic rams having ram arms coupled to the gate valve for moving the gate valve between the open and closed positions.
4. The valve assembly of any one of claims 1 to 3 wherein the first and second seals each comprise a stuffing box and a gland follower defining a cavity, the first and second slots passing through the respective stuffing boxes and gland followers, and the cavity receiving packing material so that the packing material seals against the gate valve when the gate valve is in both the open and closed positions. The valve assembly of any of claims 1 to 4 wherein the coupling portions of the housing comprise first flanges on a top end of the housing and second flanges on a bottom end of the housing.
6. The valve assembly of any one of claims 1 to wherein guard assemblies are provided on opposed sides of the housing for guarding the gate valve when the gate valve is in both an open and closed position to prevent injury to a person during movement of the gate valve from the open to the closed position.
7. The valve assembly of claim 6 wherein the stuffing boxes and gland follower are coupled together by retaining bolts. H: \pauad\Keep\speci\STABLE-slide-valve-asseydoc 25/06/99 13
8. A valve assemible substantially as hereinbefore described with reference to the accompanying drawings. Dated this 25th day of June 1999 STABLE AUSTRALIA PTY LTD By their Patent Attorneys GRIFFITH HACK Fellows institute of Patent and Trade Mark Attorneys of Australia H: \paulad\Keep\speci\STABLE-sidevaveassen-byaoc 25/06199