GB2276096A

GB2276096A - Filter for milk

Info

Publication number: GB2276096A
Application number: GB9304665A
Authority: GB
Inventors: Ross Bryan Barrington
Original assignee: FILTERWELL INTERNATIONAL LIMIT; Ambic Equipment Ltd
Current assignee: FILTERWELL INTERNATIONAL LIMIT; Ambic Equipment Ltd
Priority date: 1993-03-08
Filing date: 1993-03-08
Publication date: 1994-09-21
Anticipated expiration: 2013-03-08
Also published as: GB2276096B; GB9304665D0

Abstract

A milk filter comprises a housing having an inlet (3) and an outlet (5) and enclosing a tubular filter element, which is made from a sheet of non-shape retaining bonded fibre material held between two supporting members to constrain it to a pleated configuration. One of the supporting members is in the form of a core 7 comprising a hollow perforate tube 8 with a plurality of radially projecting perforate vanes 9. The other supporting member comprises parallel perforate elongate ribs 13 connected together by at least one flexible element 14 so that this member can be wrapped around the core to hold the filter material against the core. End caps and an outer stockinette filter sleeve are then added. The filter element is dismantled and the filter materials replaced when clogged. <IMAGE>

Description

FILTER DEVICE Filters are known in applications such as the filtration of milk in which the filter element is a cylindrical sleeve of bonded fibre fabric which fits over and is supported by a tubular perforate support. The sleeve is replaced when it becomes clogged. In order to increase the capacity of such a filter it has been proposed simply to increase its size. This increases the manufacturing cost of the filter and means that an existing standard housing cannot be used.

According to the present invention a filter device comprises a housing having an inlet and an outlet on opposite sides of a filter element, the filter element being a non-shape retaining sheet material which is held between two supporting members in a pleated configuration.

The invention increases the capacity of a filter of given overall dimensions by providing a pleated filter element which has a greater effective cross sectional area than a cylindrical element. This has not previously been considered practical in applications such as milk filtration where the filter element does not retain its shape and therefore cannot be pleated prior to being placed in a filter device.

Although the arrangement may be generally planar, the filter is preferably a circular configuration with the filter element providing a barrier between a radially inner and a radially outer space, one of which communicates with the inlet and the other of which communicates with the outlet.

The first supporting member is preferably a core comprising a hollow perforate elongate cylinder with a plurality of radially outwardly projecting perforate vanes, the perforations of which communicate with the perforations in the cylinder; and the second supporting member is preferably a retainer comprising a plurality of perforate elongate ribs each of which is fitted between a respective pair of adjacent vanes. The ribs are preferably connected together by at least one flexible belt. The filter device can thus easily be assembled by wrapping the retainer around the core with the filter element sandwiched in between, so that the initially flat filter element is successively crimped into the grooves between the vanes in the first supporting member. To facilitate this assembly the ribs preferably have a wedge shaped transverse crosssection.

Once the retainer has been rolled up around the core, they may be held in place by fasteners on the belt(s).

Preferably however a cap is fitted over each end of the core and retainer to hold them together.

The filter element of non-shape retaining material is preferably a bonded fibre fabric.

In order to provide a second stage of pre-separation, in the usual case in which the flow is radially inwardly into the core, a sleeve such as of stockinette, providing a second filter element, may be fitted around the assembled core and retainer.

An example of a filter device constructed in accordance with the present invention will now be described with reference to the accompanying drawings in which: Fig. 1 is an exploded perspective view of the device; Fig. 2 is a lateral cross section through the device; and Fig. 3 is a perspective view of the two supporting members prior to assembly of the device.

The filter device has a housing comprising hollow cylindrical body 1 closed at one end by an inlet screw plug 2 and at the other end by an outlet cap 3. The inlet plug 2 has two inlets 3 which communicate with an annular space 4 in the inlet cap 2. The outlet cap 3 is provided with an outlet 5.

A filter assembly 6 is provided within the housing.

The filter element assembly 6 comprises a core 7 in the form of a hollow elongate cylindrical central portion 8 with a plurality of radially outwardly projecting vanes 9.

The central portion 8 is provided with an array of perforations 10 arranged in columns adjacent to the vanes 9. Each vane 9 is provided with a corresponding plurality of through holes 11 which communicate with respective holes 10 in the central portion 8.

A retainer 12 consists of a number of elongate ribs 13 which corresponds to the number of vanes 9. The ribs 13 are connected together by two flexible belts 14 running perpendicular to the direction of the ribs. The ribs 13 are sized, shaped and spaced in such a way that when the retainer 12 is wrapped around the core 7 each rib fits into a groove between a respective pair of adjacent vanes 9 to fill substantially the space between the vanes. The ribs 13 have a wedge shape lateral cross-section. The wide face of each vane 13 is provided with a plurality of inlets 15 which communicate with respective outlets 16 in the two side faces of the rib 13.

In order to assemble a filter assembly 6, the retainer 12 is laid out as shown in figure 3 and a filter element of bonded fibre fabric 17 is laid over the ribs 13. The core 7 is pressed onto the retainer 12 with one of the vanes 9 being pushed between two adjacent ribs 13 so that the filter element forms a pleat between the two ribs and surrounding the vane. The core 7 is then rolled along the retainer 12 to the left as shown in figure 3. This causes the filter element 17 to form a series of pleats as the retainer 12 is wrapped around the core 7 forming the filter element 17 into the sinuous configuration shown in figure 2.

Once the retainer 12 has been fully rolled onto the core 7 the ends of the element 17 may be gathered partially over the ends of the core and an end cap 19, 20 is fitted over each end of the assembly to hold it in place. A sleeve 18 of stockinette is fitted over the assembly.

In order to facilitate the rolling of the retainer 12 onto the core 7 the wedge shape ribs 13 are formed with an asymmetrical cross-section. As can be seen from figure 3 the face of the rib facing away from the direction of rolling of the core 7 is substantially perpendicular to the wide face of the wedge. The other face of the wedge is inclined with respect to the wide face.

In use, the contaminated liquid is fed into the inlet cap 2 via inlets 3 and passes through the annular space 4 into an annular space 21 defined between the cylindrical body 1 and the filter assembly 6. The liquid flows through the sleeve 18 where it undergoes preliminary filtration.

It then flows into the ribs 13 via inlets 15 and out of the ribs 13 through outlets 16 and hence through the filter element 17 and undergoes secondary filtration. The filtered liquid flows into the vanes 9 of the core 7 through the through holes 11 and into the central portion 8 through the perforations 10. The central portion 8 of the core communicates with the outlet 5.

When the filter element 17 becomes clogged it can be replaced by unscrewing the inlet cap 2 from the cylindrical body 1 and removing the filter element assembly 6. The end caps 19, 20 and sleeve 18 are removed allowing the retainer 12 to be unrolled from the core 7. The contaminated filter element 17 can then be taken out and substituted by a fresh one in the manner described above. The stockinette sleeve can also be replaced at this time if necessary.

Claims

1. A filter device comprising a housing having an inlet and an outlet on opposite sides of a filter element, the filter element being a non-shape retaining sheet material which is held between two supporting members in a pleated configuration.

2. A filter device as claimed in claim 1, wherein the filter device is of a circular configuration and wherein the filter element provides a barrier between a radially inner and a radially outer space, one of which communicates with the inlet and the other of which communicates with the outlet.

3. A filter device as claimed in claim 1 or claim 2, wherein one of the supporting members is a core comprising a hollow perforate elongate cylinder with a plurality of radially outwardly projecting perforate vanes, the perforations of which communicate with the perforations in the cylinder.

4. A filter device as claimed in claim 3, wherein the other supporting member is a retainer comprising a plurality of perforate elongate ribs each of which is fitted between a respective pair of adjacent vanes.

5. A filter device as claimed in claim 4, wherein the ribs are connected together by at least one flexible belt.

6. A filter device as claimed in claim 4 or claim 5, wherein the ribs have a wedge shaped transverse cross section.

7. A filter device as claimed in any one of the preceding claims, wherein the filter element is a bonded fibre fabric.

8. A filter device having a core comprising a hollow perforate elongate cylinder with a plurality of radially extending projecting perforate vanes, a filter element, and an outer supporting member comprising a plurality of perforate elongate ribs connected together by at least one flexible element so that this outer supporting member can be wrapped around the core to hold the filter element against the core.

9. A filter device substantially as hereinbefore described with reference to the accompanying drawings.