US-12623165-B2 - Filter plate assembly for a horizontal plate and frame-type filter, such as a tower press, a filter plate and a vat liner

Abstract

A filter plate assembly which is resistant to both wear and deformation caused by creeping, while facilitating maintenance thereof. A filtrate vat is provided that is formed on, and integral with the filter plate, in addition to a separate, replaceable vat liner. In this way, a rigid structure of the filtrate vat capable of resisting deformation may be achieved, while the vat liner separates the filtrate from the filtrate vat and the associated filter plate, providing wear resistance and facilitating maintenance. The present disclosure further concerns the filter plate and the filtrate vat.

Inventors

• Mirva MUSTAKANGAS
• Ismo JUVONEN
• Janne KAIPAINEN
• Teemu ELORANTA
• Mika ILLI
• Kari VÄNTTINEN

Assignees

• Metso Findland Oy

Dates

Publication Date

20260512

Application Date

20200603

Claims (16)

1. 1 . A filter plate assembly for a horizontal plate and frame filter, comprising a filter plate having a rigid body with a frame side and a chamber side, wherein the filter plate comprises, on the chamber side, a border having an inner lateral wall and an upper surface, the border being elevated for a distance from a portion of the filter plate delimited within the border, and wherein the border is an integral part of the filter plate, wherein a filtrate vat is formed by the filter plate, such that the inner lateral wall of the border forms a lateral wall of the filtrate vat, and a portion of the filter plate delimited by the border forms a bottom of the filtrate vat, and wherein the filter plate assembly further comprises a vat liner having a body, the vat liner being nested within the filtrate vat such that the vat liner extends onto the upper surface of the border, such that the filter plate is separated from filtrate within the filtrate vat by the vat liner.
2. 2 . The filter plate assembly according to claim 1 , wherein the border has an outer lateral wall, and wherein the vat liner extends onto the lateral outer wall.
3. 3 . The filter plate assembly according to claim 2 , wherein a trough is formed on the vat liner, running along the perimeter thereof, wherein the border is nested within the trough, and wherein an inside of the trough is hollow and the border is solid.
4. 4 . The filter plate assembly according to claim 1 , wherein a gap is provided on the border, such that an outlet opening extending laterally through the border is formed, thereby providing a fluid drainage route from the filtrate vat.
5. 5 . The filter plate assembly according to claim 4 , wherein the vat liner is formed so as to extend into the outlet opening, and to cover the border adjacent to the outlet opening, such that the filter plate is separated from filtrate within the outlet opening by the vat liner.
6. 6 . The filter plate assembly according to claim 4 , wherein, on the chamber side of the filter plate, a recessed portion of the filter plate situated at the outlet opening is recessed with respect the bottom of the filtrate vat, and wherein the vat liner is spaced apart from the filter plate at the recessed portion in a direction transverse to a general planarity of the filter plate.
7. 7 . The filter plate assembly according to claim 4 , further comprising a removably fixed outlet piece at least partly nested within the outlet opening, wherein the outlet piece being arranged such that the fluid drainage route runs therethrough.
8. 8 . The filter plate assembly according to claim 7 , wherein the vat liner extends into the outlet piece.
9. 9 . The filter plate assembly according to claim 8 , wherein the outlet piece comprises: a base at least partly nested within a recessed portion of the filter plate, between the filter plate and the vat liner, and a lid on an opposite side of the vat liner with respect to the base, wherein the base is removably fixed to the filter plate assembly, and wherein the lid is a removably fixed to the base such that the vat liner is clamped between the base and the lid and a sealed attachment between the outlet piece and the vat liner is formed, and wherein the filtrate drainage route is formed between the vat liner and the lid.
10. 10 . The filter plate assembly according to claim 9 , wherein the base of the outlet piece comprises a recessed seat into which a gap portion of the vat liner, corresponding to a gap of the border, is seated, wherein the lid comprises a plurality of spaced apart ribs projecting towards the recessed seat, such that the vat liner is clamped between the recessed seat and the ribs, and is sealed against the recessed seat, and wherein the lid extends over the gap and seals against the border portion of the liner at a position corresponding to the upper surface of the border.
11. 11 . The filter plate assembly according to claim 10 , wherein the base comprises a recessed chute as a continuation of the recessed seat for conducting filtrate out of the outlet piece.
12. 12 . The filter plate assembly according to claim 4 , wherein the filter plate is of a generally rectangular shape having a first flank side and a second flank side parallel to the first flank side, and a first end side and a second end side parallel to the first end side, wherein the first and second end sides extend in a direction transverse to a direction in which the first and second flank sides extend, wherein the first and second flank sides have a length greater than that of the first and second end sides, and wherein one or more gaps of the border are formed on either or both of the first flank side and the second flank side.
13. 13 . The filter plate assembly according to claim 12 , wherein a gap of the border is formed in a corner region between a flank side and an end side.
14. 14 . The filter plate assembly according to claim 12 , wherein the filter plate comprises one or more lateral indentation portion provided on either or both of the first flank side and the second flank side, wherein the lateral indentation portion is arranged to circumvent suspension elements and/or support elements of a filter plate frame on which the filter plate is supported.
15. 15 . The filter plate assembly according to claim 14 , wherein the filter plate comprises one or more lateral widening portions provided on either or both of the first flank side and the second flank side, wherein the lateral widening portions are arranged between lateral indentation portions adjacent to the widening portion, wherein the lateral widening portions are arranged to laterally overhang a filter plate frame supporting the filter plate.
16. 16 . The filter plate assembly according to claim 2 , wherein the filter plate comprises a plurality of attachment holes running along a periphery of the filter plate and extending therethrough, wherein the attachment holes are situated on an outer side of the border with respect to the filtrate vat, such that the attachment holes are not in contact with filtrate within the filtrate vat, when in use.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is the U.S. national stage application of International Application PCT/FI2020/050389, filed Jun. 3, 2020, which international application was published on Dec. 9, 2021, as International Publication WO 2021/245321 A1 in the English language. FIELD OF THE DISCLOSURE The present disclosure relates to horizontal plate and frame-type filters, such as tower presses, and more particularly to a filter plate assembly for such a filter. The present disclosure further concerns a filter plate and a vat liner for such a filter plate assembly. BACKGROUND OF THE DISCLOSURE Conventionally in horizontal filter plate and frame-type filters, such as tower presses, a filtrate is collected to a filtrate vat from a filter chamber formed above the vat. As the filtrate typically contains small solid particles, the filtrate flow (and a possible drying air flow) is abrasive over numerous repeated filtration cycles. To this end, the filtrate vat has conventionally been provided as a separate, replaceable component, made of a material able to sufficiently withstand wear caused by the abrasive flow. In known arrangements, the filtrate vat has been provided as component forming a receptacle for receiving the filtrate and has been placed on top of a substantially flat filter plate. When the filtrate vat has worn excessively, it is replaced. However, it has been noticed, that such a wear resistant separate filtrate vat is prone to creeping under as it is repetitively compressed over numerous filtration cycles. Moreover, it has not been generally considered that changing the material of the filtrate vat so as to better resist deformation due to creeping would result in unsatisfactory wear-resistance characteristics. It has also been noted that conventional, separate filtrate vats have faced issues related to contamination from the slurry to be filtered and other process fluids. Particularly, slurry that has reached the interface between the filter plate and the filtrate vat may travel underneath the filtrate vat due to the capillary effect and the repetitive compression of the filtration cycles. Such impurities cause a bulge on the otherwise flat filter plate, thereby leading to premature wear of the filtrate vat and even breakage thereof. Moreover, slurry or other process fluid contamination may seize fasteners used to attach the filtrate vat to the filter plate, thereby hindering the maintenance of the associated filter, such as replacement of the filtrate vat. BRIEF DESCRIPTION OF THE DISCLOSURE An object of the present disclosure is to provide a filter plate assembly, a filter plate and a vat liner, which are resistant to both wear and deformation caused by creeping, while facilitating maintenance. The object of the disclosure is achieved by the filter plate assembly, the filter plate and the vat liner which are characterized by what is stated in the independent claims. The preferred embodiments of the disclosure are disclosed in the dependent claims. The disclosure is based on the idea of providing the filtrate vat formed on, and integral with the filter plate, in addition to a separate, replaceable vat liner. In this way, a rigid structure of the filtrate vat capable of resisting deformation may be achieved, while the vat liner separates the filtrate from the filtrate vat and the associated filter plate, providing wear resistance and facilitating maintenance. BRIEF DESCRIPTION OF THE DRAWINGS In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which FIG. 1 illustrates a plan view of a filter plate assembly according to an embodiment of the present invention; FIG. 2 illustrates a cross-sectional cut view along the cut line illustrated in FIG. 1; FIG. 3 illustrates a filter plate assembly similar to that of FIG. 1, without outlet pieces, and equipped with a filtrate vat, as seen as an exploded perspective view; FIG. 4 illustrates the filter plate assembly of FIG. 3 as seen as a plan view; FIG. 5 illustrates the filter plate assembly of FIG. 3 as an exploded cross section cut view along the dashed line illustrated in FIG. 4; FIG. 6 illustrates the filter plate assembly of FIG. 3 as a cross section cut view along the dashed line illustrated in FIG. 4; FIG. 7 illustrates the filter plate assembly of FIG. 1, as seen as a semi-exploded perspective view; FIG. 8 illustrates a detailed view of the outlet piece of FIG. 7; FIG. 9 illustrates the situation of FIG. 8 in a non-exploded view; FIG. 10 illustrates the filter plate assembly of FIG. 7 as a plan view; FIG. 11 illustrates an exploded partial cross-sectional cut view of the filter plate assembly of FIG. 7, along the dashed line illustrated in FIG. 10, and FIG. 12 illustrates the situation of FIG. 11 in a non-exploded view. DETAILED DESCRIPTION OF THE DISCLOSURE According to a first aspect of the present disclosure, a filter plate assemb