WO2023007400A1

WO2023007400A1 - Drain valve assembly for filter plates

Info

Publication number: WO2023007400A1
Application number: PCT/IB2022/056952
Authority: WO
Inventors: James CHAPONNEL; Thegn WISE
Original assignee: Flsmidth A/S
Priority date: 2021-07-27
Filing date: 2022-07-27
Publication date: 2023-02-02

Abstract

An overpressure valve (1) is disclosed. The overpressure valve (1) is configured as a drain valve assembly (1) for a filter plate (7) within a horizontal filter press. The overpressure valve (1) has a plug (5) provided with an upper collar (5a), a pressure surface (5d), a sealing surface (5e) below the pressure surface (5d), and a plurality of elastomeric webs (5b) extending between the upper collar (5a) and the pressure surface (5d). The webs (5b) are configured to elastically deform or temporarily stretch when the pressure surface (5d) is exposed to pressure and are preferably non-metallic to improve wear performance from abrasion and/or corrosion.

Description

DRAIN VALVE ASSEMBLY FOR FILTER PLATES

FIELD OF THE INVENTION

This invention relates to industrial overpressure valves. Embodiments may find particular use as a drain valve assembly within filtration systems, such as horizontal filter presses which are configured to dewater slurry and form filter cakes. The drain valve assembly may be positioned into lower portions of a filter plate of a filter press. Embodiments of the drain valve assembly may be configured to prevent flow therethrough under air blow cycles, and allow flow therethrough when there is no pressure inside the filter chamber.

The disclosed drain valve assembly may find utility and industrial applicability outside of the filtration arts - for example, in any application suitable where overpressure valves are used (e.g., in systems, devices, or any apparatus configured for conveying abrasive and/or corrosive fluid mediums - including, but not limited to those within the mining, minerals processing, concrete, slurry transport, and drilling industries). Abrasion and corrosion-resistant elastomeric spring components within the valve assembly aim to improve upon standard valve configurations (which use metallic springs and are thus subject to premature wear).

BACKGROUND OF THE INVENTION

Industrial filter presses are used to dewater slurries. Buildup of solids within filter chambers defined between adjacent filter plates can trap solids, thereby leading to hastened wear of filter plate material and filter cloths. There is a long-felt need for a simple, dependable, and inexpensive manner in which to encourage safe egress of accumulating solids from lower portions of a filter plate (e.g., on a back side of filter media). There is also a long-felt need for an overpressure valve that is more resistant to wear from abrasive and/or corrosive fluid mediums.

OBJECTS OF THE INVENTION

An aim of embodiments of the present invention is to provide a drain valve assembly 1 for filter plates 7 which is simple, easily constructed, reliable, and inexpensive to rebuild, in order to allow egress of accumulated solids from lower portions of filter plates 7, without limitation. A further aim of embodiments of the present invention is to provide an improved overpressure valve 1 for systems, devices, or any apparatus configured for conveying abrasive and/or corrosive fluid mediums.

Yet another aim of embodiments of the present invention is to provide a valve assembly having one or more elastomeric spring-like members for actuating a plug that seals to provide better resistance to wear from abrasion and/or corrosion than conventional valves which use metallic spring members, without limitation.

SUMMARY OF THE INVENTION

A drain valve assembly (1) for a filter plate (7) within a horizontal filter press is disclosed. The drain valve assembly (1) may comprise a plug (5). The plug (5) may have an upper collar (5a), a pressure surface (5d), a sealing surface (5e) below the pressure surface (5d), and one or more webs (5b, 5g) extending between the upper collar (5a) and pressure surface (5d). The one or more webs (5b) may include a plurality of webs (5b), without limitation. Some or all of the one or more webs (5b) may comprise a straight or helical-shaped web (5g), without limitation. The one or more webs (5b, 5g) may be configured to elastically deform or temporarily stretch when the pressure surface (5d) is exposed to pressure. Upon exposure to a pressure above a predetermined threshold, and by virtue of elastic deformation or temporary stretching of the one or more webs (5b, 5g), the sealing surface (5e) of the plug (5) comes into contact with a sealing surface (4e) of a lower hollow body (4) or adjustable member (4', 6) receiving the plug (5) therein. When the sealing surfaces (4e, 5e) come into contact, material is prevented or hindered from passing through the drain valve assembly (1), without limitation.

According to some non-limiting embodiments, the drain valve assembly (1) may comprise an upper tube (2). The upper tube (2) may comprise a central bore (2a), an upper outer threaded portion (2b), a middle portion (2c), and/or a lower outer threaded portion (2d), without limitation.

According to some non-limiting embodiments, the drain valve assembly (1) may comprise a middle tube (3). The middle tube (3) may comprise an outer torque surface (3a), an outer threaded portion (3b), an inner threaded portion (3c), and/or a centering surface (3d), without limitation. The middle tube (3) may comprise a passageway (3e) for material to pass therethrough, without limitation. In some embodiments, the upper tube (2) may be coupled to or threadedly received within the middle tube (3), without limitation. In some embodiments, the middle tube (3) may be coupled to or threadedly received within the lower hollow body (4), without limitation.

In some non-limiting embodiments, the lower hollow body (4) may comprise an adjustable member (4'). The adjustable member (4') may have an outer threaded portion (4h) and bore (4b) which may be provided to the hollow body (4), such that a distance between the sealing surfaces (4e, 5e) can be adjusted.

In some non-limiting embodiments, the lower hollow body (4) or adjustable member (4', 6) may comprise a one-piece adjustable member (6). The one-piece adjustable member (6) may have an outer threaded portion (6h), a bore (6b), and an upper collar (6c) for supporting an upper collar (5a) of the plug (5), without limitation.

In some embodiments, the drain valve assembly (1) may comprise a seal (6g) for provision between portion of (e.g., a component of) the drain valve assembly (1) and a portion of a filter plate (7), without limitation. For example, as shown, the seal (6g) may be provided on an exterior portion of the drain valve assembly (1).

According to some embodiments, a drain valve assembly (1) may comprise a plug (5) having a pressure surface (5d), a sealing surface (5e) below the pressure surface (5d), and one or more helically-shaped webs (5b) extending upwardly from the pressure surface (5d) to an upper collar (5a). The one or more helical webs (5b) may be configured to elastically deform or temporarily stretch when the pressure surface (5d) is exposed to pressure. Upon exposure to a pressure above a predetermined threshold, and by virtue of elastic deformation or temporary stretching of the one or more helical webs (5b), the sealing surface (5e) of the plug (5) comes into contact with a sealing surface (4e) of a lower hollow body (4) or adjustable member (4', 6) receiving the plug (5) therein. In such embodiments, the drain valve assembly (1) may comprise a middle tube (3) comprising a passageway (3e) and a hub (3h) disposed within the passageway

(3e). The hub (3h) may be supported by one or more bridge members (3f). The hub (3h) may comprise a bore (3g) for receiving an upper portion of the plug (5), such as the upper collar (5a), without limitation.

In such embodiments, the lower hollow body (4) or adjustable member (4', 6) may comprise a bore (4b) extending therethrough, and a post (4k) centrally provided within the bore (4b). The post (4k) may be supported by at least one bridge member (41) as shown. The post (4k) may be provided within a bore (5h) of the plug (5) which is positioned radially-inward of the sealing surface (5e) of the plug (5). For example, the post (4k) may be positioned so as to be located radially-inwardly of the one or more helical webs (5b) of the plug (5). In this regard, the post (4k) may co-axially guide movement of the plug (5) such that its sealing surface (5e) can remain concentrically-aligned with the sealing surface (4e) of lower body (4).

A method of refurbishing a drain valve assembly (1) is also disclosed. The method may comprise one or more of the following steps in any order. The method may comprise the step of rotating a component (2, 3, 4, 4', 6) of the drain valve assembly (1) to release the plug (5) from captivity within the drain valve assembly (1). The method may comprise the step of removing the plug (5) from the drain valve assembly (1). The method may comprise the step of replacing the plug (5) with another plug (5). The method may comprise the step of rotating a component (2, 3, 4, 4', 6) of the drain valve assembly (1) to capture said another plug (5) within the drain valve assembly (1).

In some embodiments, the drain valve assembly (1) may be provided to a filter plate (7), and one, some, or all of the aforementioned steps may be performed when the filter plate (7) is positioned/installed within a horizontal filter press. In some embodiments, one, some, or all of the aforementioned steps may be performed when the filter plate (7) is separated from a horizontal filter press. In some embodiments, one, some, or all of the aforementioned steps may be performed before, after, or during removal of filter media from a filter plate (7).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a non-limiting exemplary embodiment of a drain valve assembly 1 according to the invention.

FIG. 2 is a bottom view of the drain valve shown in FIG. 1.

FIG. 3 is a top view of the drain valve shown in FIGS. 1 and 2.

FIG. 4 is a side view of the drain valve shown in FIGS. 1-3, but which is shown without its lower hollow body 4.

FIGS. 5 and 6 are isometric views of a plug 5 within the drain valve assembly 1 shown in FIGS. 1-4.

FIG. 7 is an upper isometric view of the lower hollow body 4 shown in FIGS. 1-3 and omitted from FIG. 4 for clarity.

FIG. 8 is an exploded view of the drain valve assembly 1 and components thereof shown in FIGS. 1-7.

FIG. 9 is a side cross-sectional view of the drain valve assembly 1 and components thereof shown in FIGS. 1-8, wherein a sealing surface 4e of the lower hollow body 4 is fixed.

FIG. 10 is a side cross-sectional view of a second non-limiting exemplary embodiment of a drain valve assembly 1 according to the invention, which is configured for adjustment of a sealing surface 4e of the lower hollow body 4. FIGS 11 and 12 show side cross-sectional views of a third non-limiting exemplary embodiment of a drain valve assembly 1 according to the invention, wherein a one-piece adjustable member 6 is threaded into a filter plate 7 to secure a plug 5 within a lower bore 7b of the filter plate 7.

FIGS. 13-18 show various views and components of a drain valve assembly 1 according to alternative non-limiting embodiments.

DETAILED DESCRIPTION

Turning now to FIGS. 1-9, a drain valve assembly 1 for a filter plate 7 may include several components. For example, drain valve assembly 1 may include an upper tube 2 connected to a middle tube 3. The middle tube 3 may be connected to a lower hollow body 4. A plug 5 may be captured between the middle tube 3 and the lower hollow body 4. The drain valve assembly 1 is configured to allow material (e.g., solid/fluid mixtures) to move through it at low pressure environments above the plug 5 pressure surface 5d (e.g., during opening and closing of filter plates 7), without limitation. The drain valve assembly 1 is further configured to prevent or discourage the egress of material therethrough at higher pressure environments above the pressure surface 5d of the plug 5 (e.g., during air blow cycle within a filtration cycle of a filter press), without limitation.

The upper tube 2 may be elongated in shape and comprise a central bore 2a, an upper outer threaded portion 2b, a lower outer threaded portion 2d, and a middle portion 2c therebetween. The middle portion 2c may be unthreaded as shown, and the upper tube 2 may be configured as a standard pipe fitting, without limitation. The upper outer threaded portion 2b may be configured to be threadedly received in a lower bore 7b or inner threaded portion 7c of a filter plate 7 as suggested in FIGS. 11 and 12.

The middle tube 3 may comprise an outer torque surface 3a, an outer threaded portion 3b, and an inner threaded portion 3c as shown. A centering surface 3d may extend downward from the outer threaded portion 3b as shown. The centering surface 3d may serve to abut and/or guide an upper bore 5f of an upper collar 5a of the plug 5 as will be appreciated hereinafter and from the drawings. The inner threaded portion 3c is preferably configured to receive the outer threaded portion 2d of the upper tube 2, without limitation. By engaging the outer torque surface 3a, the middle tube 3 may be rotated with respect to the lower hollow body 4 to capture an upper collar 5a of the plug between a lower portion of the middle tube 3 and a shelf 4f of the lower hollow body 4 as shown in FIGS. 10 and 11, without limitation.

The lower hollow body 4 may, as shown, comprise a lower surface 4a, a bore 4b extending through the lower surface 4a, an inner wall surface 4c which is greater in diameter than the bore 4b, an upper inner threaded portion 4d, a sealing surface 4e extending between the bore 4b and inner wall surface 4c, and a shelf 4f. The shelf 4f may be provided above the inner wall surface 4c. By virtue of its tubular shape, the lower hollow body 4 provides a cavity for receiving the plug 5 as demonstrated in the figures.

The plug 5 may, as shown, comprise an upper collar 5a, a pressure surface 5d facing upwards (e.g., towards the middle tube 3), and a number of webs 5b extending between the upper collar 5a and the pressure surface 5d. A number of ports 5c are defined between the webs 5b as shown. The ports 5c may be configured to allow material to pass through an upper bore 5f through the upper collar 5a, and around outer surface portions of the plug 5.

In open configurations of the drain valve assembly 1, the material can pass through a gap which temporarily exists between a lower sealing surface 5e of the plug 5 and the sealing surface 4e of the lower hollow body 4. In closed configurations of the drain valve assembly 1, for example, during a high-pressure air blow cycle, pressure from within a filter chamber defined by adjacent filter plates 7 acts against pressure surface 5d thereby stretching the webs 5b and biasing the sealing surface 5e of the plug 5 against the sealing surface 4e of the lower hollow body 4. The sealing surfaces 4e, 5e may be complimentarily shaped as shown. Each sealing surface 4e, 5e may be frustoconical or frustospherical, without limitation. One or both of the sealing surfaces may be smooth as shown or may be undulating, ribbed, or corrugated, without limitation. One or both of the sealing surfaces may comprise one or more lip or ring seals (e.g., concentric sealing protrusions extending from either or both sealing surfaces 4e, 5e), without limitation. One of the sealing surfaces (e.g., sealing surface 5e of the plug 5) may have a round surface, and the other one of the sealing surfaces (e.g., sealing surface 4e of the lower hollow body 4) may have a flat or frustoconical tapered surface, without limitation.

Turning now to FIGS. 10-12, in some embodiments, a distance between sealing surfaces 4e, 5e can be adjusted to fine tune sealing effectiveness of the drain valve assembly 1 - or, to compensate for wearing or stretching of webs 5b.

For example, FIG. 10 shows an embodiment wherein an adjustable member 4' may be provided to the lower hollow body 4. The adjustable member 4' may comprise an outer upper threaded portion 4h which engages an inner lower threaded portion 4g provided to the lower hollow body 4. An outer torque surface 4i may be provided to the adjustable member 4' to facilitate turning of the adjustable member 4' with respect to the lower hollow body 4. By virtue of threads in the threaded portions 4h, 4g, the relative axial positioning between the lower hollow body 4 and adjustable member 4' may be adjusted, thereby orienting the sealing surface 4e of the lower hollow body 4 closer or more distant from the sealing surface 5e of the plug 5. In such embodiments, the bore 4b and sealing surface 4e of the lower hollow body 4 may be provided to the adjustable member 4'. Upon relative rotation between adjustable member 4' and lower hollow body 4, a lower surface 4j of the adjustable member 4' may move, effectively changing the location of a distal lower end of the lower hollow body 4 relative to lower surface 4a.

Turning now to FIGS. 11 and 12, in some embodiments of a drain valve assembly 1, a filter plate 7 may be provided with an upper bore 7a, a lower bore 7b, and an inner threaded portion 7c. A one-piece adjustable member 6 of the drain valve assembly 1 may be inserted into the lower bore 7b and secured to the inner threaded portion 7c of the filter plate 7 via an outer threaded portion 6h. This may be done by engaging an outer torque surface 6i of the one-piece adjustable member 6 and rotating it in relation to the filter plate 7, until an upper collar 6c of the one-piece adjustable member 6 contacts a lower portion of and upper collar 5a of the plug 5 as shown. Further tightening of the one-piece adjustable member 6 into the filter plate 7 may compress the upper collar 5a of the plug 5 and decrease the distance between sealing surfaces 6e and 5e.

The one-piece adjustable member 6 shown in the embodiment of FIGS. 11 and 12 may comprise a lower surface 6a, a bore 6b for allowing material to pass through the lower surface 6a, an upper collar 6c for receiving a plug 5 and for applying pressure to an underside of an upper collar 5a of the plug to secure the plug 5 within the lower bore 7b of the filter plate, without limitation. The one-piece adjustable member 6 may further comprise an inner wall surface 6d for receiving material from upper bore 7a flowing through the ports 5c of plug 5. The adjustable member may further comprise a sealing surface 6e for engaging sealing surface 5e of plug 5, when the pressure surface 5d is exposed to a high-pressure environment and webs 5b are stretched. A seal cavity 6f may be provided at a peripheral surface of the one-piece adjustable member 6 for receiving a seal 6g. The seal 6g may be positioned between lower bore 7b and the one-piece adjustable member 6 in any manner. While not shown, it is envisaged that seal 6g may be positioned between upper collars 5a, 6c, without limitation. Moreover, while not shown, it is envisaged that seal 6g may be provided as a sealing washer or O-ring at a ledge or shelf portion just above outer threaded portion 6h, without limitation.

Turning now to FIGS. 13-17, in some embodiments, a drain valve assembly 1 in accordance with the invention may include a middle tube 3 having a central hub 3h. The central hub 3h may be configured with a bore 3g, and may be supported within the middle tube 3 by a number of bridge members 3f as shown. A passageway 3e defined by a number of fenestrations between the bridge members 3f may allow material to flow therethrough. The bore 3g may be configured to serve one or more purposes. For example, the bore 3g may receive an upper collar 5a or upper portion of one or more helical webs 5b of a plug 5. The bore 3g may also be configured to receive an upper portion of a post 4k provided to lower hollow body 4 or adjustable member 4', 6, without limitation. The plug 5 may comprise a pressure surface 5d and a sealing surface 5e as with the aforementioned embodiment. However, a single web 5b or a plurality of webs 5b may be provided to the plug 5 in the form of a helix. The one or more webs 5b may extend between an upper collar 5a and pressure surface 5d of the plug 5. The one or more webs 5b may be provided proximate a central region of plug 5 as shown. The plug 5 may comprise a bore 5h positioned along a longitudinal axis (not shown) of plug 5. The bore 5h, for example, may extend through the center of plug 5 at its distal end radially-inwardly of sealing surface 5e, without limitation. The bore 5h may receive the post 4k. The post 4k may reside within the one or more helical webs 5b to guide stretching movement of plug 5, such that sealing surface 5e moves up and down within lower hollow body 4 concentrically and in coaxial alignment with components of the drain valve assembly 1. The post 4k may be supported by a number of bridge members 41 extending within bore 4b of the lower hollow body 4 or adjustable member 4', 6, without limitation.

Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. For example, it should be noted that the drain valve assembly 1 discussed herein may find applicability and utility outside of filtration and/or minerals processing in any application suitable where overpressure valves are used (e.g., in systems, devices, or any apparatus configured for conveying abrasive mediums or even semi-abrasive mediums). Using one or more of the novel and inventive elastomeric/elastically-deforming spring-like webs 5b to actuate a plunging sealing surface 5e of a plug 5 (rather than a conventional metallic spring to actuate the sealing surface), spring wear from abrasive slurry in the valve 1 can be reduced due to the wear-resistant elastomers in the webs 5b.

Nomenclature and technical terms used in this description and the claims to define features has been chosen for convenience, and it should be understood that specific terms used herein may be replaced with art- recognized equivalents without departing from the scope and spirit of the invention. For example, where used herein, the term "drain valve assembly" could be used synonomously and intergchangeably with "overpressure valve".

Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof. LISTING OF ENUMERATED FEATURES

1 Drain valve assembly (i.e., "overpressure valve")

2 Upper tube 2a Central bore

2b Upper outer threaded portion

2c Middle portion

2d Lower outer threaded portion

3 Middle tube

3a Outer torque surface 3b Outer threaded portion 3c Inner threaded portion 3d Centering surface 3e Passageway 3f Bridge member(s)

3g Bore 3h Hub

4 Lower hollow body 4' Adjustable member 4a Lower surface

4b Bore

4c Inner wall surface 4d Upper inner threaded portion 4e Sealing surface 4f Shelf

4g Inner lower threaded portion 4h Outer upper threaded portion 4i Outer torque surface 4j Lower surface 4k Post

41 Bridge member(s)

5 Plug a Upper collar b Web(s) (e.g., straight, helical, one or a plurality)c Ports d Pressure surface e Sealing surface f Upper bore h Bore One-piece adjustable member a Lower surface b Bore c Upper collar d Inner wall surface e Sealing surface f Seal cavity g Seal h Outer threaded portion i Outer torque surface Filter plate a Upper bore b Lower bore c Inner threaded portion

Claims

What is claimed is:

1) A drain valve assembly (1) for a filter plate (7) within a horizontal filter press, the drain valve assembly (1) comprising a plug (5) having an upper collar (5a), a pressure surface (5d), a sealing surface (5e) below the pressure surface (5d), and one or more webs (5b) extending between the upper collar (5a) and pressure surface (5d) which are configured to elastically deform or temporarily stretch when the pressure surface (5d) is exposed to pressure; wherein upon exposure to a pressure above a predetermined threshold, and by virtue of elastic deformation or temporary stretching of the one or more webs (5b), the sealing surface (5e) of the plug (5) comes into contact with a sealing surface (4e) of a lower hollow body (4) or adjustable member (4', 6) receiving the plug (5) therein.

2) The drain valve assembly (1) according to claim 1, further comprising an upper tube (2).

3) The drain valve assembly (1) according to claim 2, wherein the upper tube (2) comprises a central bore (2a), an upper outer threaded portion (2b), a middle portion (2c), and/or a lower outer threaded portion (2d).

4) The drain valve assembly (1) according to any one of the preceding claims, further comprising a middle tube (3). 5) The drain valve assembly (1) according to claim 4, wherein the middle tube (3) comprises an outer torque surface (3a), an outer threaded portion (3b), an inner threaded portion (3c), and/or a centering surface (3d).

6) The drain valve assembly (1) according to any one of the preceding claims wherein the upper tube (2) is coupled to or threadedly received within the middle tube (3).

7) The drain valve assembly (1) according to any one of the preceding claims, wherein the middle tube (3) is received within, coupled to, or threadedly received within the lower hollow body (4) or adjustable member (4', 6).

8) The drain valve assembly (1) according to any one of the preceding claims, wherein the lower hollow body (4) or adjustable member (4', 6) comprises a lower hollow body (4) in combination with an adjustable member (4') having an outer threaded portion (4h) and bore (4b).

9) The drain valve assembly (1) according to any one of claims 1-7, wherein the lower hollow body (4) or adjustable member (4', 6) comprises a one-piece adjustable member (6), the one-piece adjustable member (6) having an outer threaded portion (6h), a bore (6b), and an upper collar

(6c) for supporting an upper collar (5a) of the plug (5). 10) The drain valve assembly (1) according to any one of the preceding claims, further comprising a seal (6g) provided between an exterior portion of the drain valve assembly (1) and a portion of a filter plate (7).

11) The drain valve assembly (1) according to any one of the preceding claims, wherein the one or more webs (5b) of the plug (5) are helical in shape.

12) The drain valve assembly (1) according to any one of the preceding claims, wherein the one or more webs (5b) comprises a plurality of webs (5b).

13) The drain valve assembly (1) according to any one of the preceding claims, wherein the middle tube (3) comprises a passageway (3e) and a hub (3h) disposed within the passageway (3e), the hub (3h) being supported by one or more bridge members (3f), the hub (3h) comprising a bore (3g) for receiving the upper collar (5a) of the plug (5).

14) The drain valve assembly (1) according to any one of the preceding claims, further comprising a a post (4k) centrally provided within the bore (4b) of the lower hollow body (4) or adjustable member (4', 6) and being supported by at least one bridge member (41), the post (4k) being receivable within a bore (5h) of the plug (5) adjacent the sealing surface (5e) of the plug (5).

15) A method of refurbishing a drain valve assembly (1) according to any one of the preceding claims comprising: rotating a component (2, 3, 4, 4', 6) of the drain valve assembly (1) to release the plug (5) from captivity within the drain valve assembly (1); removing the plug (5) from the drain valve assembly (1); replacing the plug (5) with another plug (5); and rotating a component (2, 3, 4, 4', 6) of the drain valve assembly (1) to capture said another plug (5) within the drain valve assembly (1).

16) The method according to claim 15, wherein the drain valve assembly (1) is provided to a filter plate (7) and all steps are performed when the filter plate (7) is within a horizontal filter press.

17) The method according to claim 15, wherein all steps are performed when the filter plate (7) is separated from a horizontal filter press.

18) The method according to claim 17, wherein all steps are performed before, after, or during removal of filter media from a filter plate (7).

19) An overpressure valve (1) for a system, device, or apparatus conveying an abrasive or corrosive fluid medium or slurry, the overpressure valve (1) comprising a plug (5) having an upper collar (5a), a pressure surface (5d), a sealing surface (5e) below the pressure surface (5d), and one or more webs (5b) extending between the upper collar (5a) and pressure surface (5d) which are configured to elastically deform or temporarily stretch when the pressure surface (5d) is exposed to pressure; wherein upon exposure to a pressure above a predetermined threshold, and by virtue of elastic deformation or temporary stretching of the one or more webs (5b), the sealing surface (5e) of the plug (5) comes into contact with a sealing surface (4e) of a lower hollow body (4) or adjustable member (4', 6) receiving the plug (5) therein.