GB2504647A

GB2504647A - Removably Retaining a Filter on a Moulding Former or Insert

Info

Publication number: GB2504647A
Application number: GB1201644.0A
Authority: GB
Inventors: Peter Francis Bullock
Original assignee: HELVETIC FILTER Co GmbH
Current assignee: HELVETIC FILTER Co GmbH
Priority date: 2012-01-31
Filing date: 2012-01-31
Publication date: 2014-02-12
Also published as: GB201201644D0

Abstract

A system adapted to removably retain a flexible filter over a least part of a surface of a moulding former or inset includes a moulding former 200 or insert having at least one surface including at least one retaining formation 202 for retaining part of a flexible filter 300. It further includes a removable member (401, figure 4a) for removably retaining the flexible filter in the retaining formation. The retaining formation may comprise a channel, groove or shaped slot along part of surfaces or side edges of the former or insert. The retaining formation may be formed on a surface which includes a texture or pattern. The removable member may be flexible or deformable and may comprise an O-ring or piece of rubber material. The filter may be paper or woven or knitted fabric. The system may be used when forming concrete moulded products such as paving slabs or kerb stones using a hydraulic press.

Description

Removably Retaining a Filter on a Moulding Former or Insert The present invention relates to removably retaining a filter on a moulding former plate, or a head plate/insert.

Figure 1 is a schematic view of the operation of a known hydraulic press machine 100 that can be used for producing paving slabs, kerbstones or variants thereof. The system comprises a mould section 102, at the bottom of which there is a former plate 104 mounted on a moveable pedestal 106.

In use, a wet mix 108 is poured into the mould section 102 and hydraulically pressed to form the product. The wet mix typically comprises a wet mix concrete with an aggregate/cement ratio of between 5:1 & 7:1. The aggregates and cement are first accurately batch-weighed and dispensed into a mixer. Water is added to this mix until a slurry is formed with an approximate water/solid ratio of 1:1. Unlike conventional pre-casting, the quantity of water is not critical since free water is forced out during pressing. Careful selection of aggregates is required to achieve quality products and best production rates.

The aggregates are pre-washed and free from contamination. The remaining dust or "fines" are used to obtain a close-texture and smooth surface on the finished product. To prevent the escape of fines as the water is drawn off by the hydraulic press, pressure is exerted through the machine and its tooling to consolidate the concrete to form a product. A sheet of porous paper can be placed onto of the former/perforated plate and/or the concrete mix. Alternatively, a filter cloth/filter cloth assembly 109 is permanently fixed to the former plate 104 before, or after, it is fitted in the machine 100.

When the press is actuated a hydraulic ram 110 presses down into the mould section 102, squeezing out the excess water from the wet mix. Pressure of the order of 600 -3000 psi is typically applied, depending on the area/size of the product being pressed. The mix easily runs and fills the mould with, or without, vibration. A paper or filter cloth is usually placed onto the concrete in a filled mould and may also be permanently attached to the die head of the tooling section (as shown at 112), which is attached to the hydraulic ram. The drainage of excess water is an important part of the process and, as the 400 ton -600 ton presses the product, drainage may be assisted by a vacuumed top drainage system. The duration of the pressing ranges from 10 seconds to 60 seconds depending on the aggregates quality/grading and characteristics and also the size of the product required.

Immediately after pressing, the product is strong enough to be handled and the moveable pedestal 106 is raised to allow the product (along with the former 104 and filter 109) to be removed from the mould section 102. It is then stacked near the machine 100 in the dry atmosphere of the building for overnight curing. In some hotter countries while curing is taking place the products are "watered" to ensure curing does not happen too quickly. The products are then stacked out in a stacking area for natural completion of curing. In some cases, this process is accelerated by use of steam curing.

As mentioned above, the filter 109 is fixed to the former plate 104. This is conventionally done in a non-removable manner by adhesive or stitching. The filter tends to become less effective after use as it gets saturated with particles.

Removing a conventionally fixed filter is time-consuming and usually results in the filter being damaged and so has to be disposed of and replaced. This has negative cost and efficiency effects, as well as leading to a significant amount of waste. The permanent filters which are typically used have a plastic perforated backer to which the filter material is attached, traditionally via adhesive and or stitching. Once the filter has been used and removed, the user generally removes the filter material from the plastic and disposes of both items separately, or, in some cases still attached together.

Embodiments of the present invention are intended to address at least some of the abovementioned problems.

According to a first aspect of the present invention there is provided a system adapted to removably retain a flexible filter over a least part of a surface of a moulding former or insert, the system including: a moulding former or insert having at least one surface including at least one retaining formation for, in use, retaining part of a flexible filter, and a removable member for, in use, removably retaining the flexible filter in the retaining formation.

The retaining formation may include a single or multiple channel, groove or shaped slot extending along at least part of the surface. The channel, groove or shaped slot may be substantially straight or curved. The channel, groove or shaped slot may extend from one side edge of the surface to another edge, typically an opposite side edge of the former/insert. One or more, e.g. a pair, of said grooves, channels or shaped slots may be formed in the surface. The grooves, channels or shaped slots may be spaced apart in any desired manner.

The groove, channel or shaped slot may follow at least part of a perimeter of the surface and may be spaced apart from it, or positioned in any required way.

The former may have at least one upstanding wall and the retaining formation may be at least partially located in an interface between a main surface of the former at the at least one upstanding wall. The upstanding wall may be perpendicular or angled with respect to the main surface. The former/insert may include a further wall extending at an angle from the upstanding wall. The retaining formation may be formed in or on the further wall.

In some embodiments, the retaining formation comprises a continuous channel running all along an upper surface the further wall.

The channel, groove or shaped slot may be formed in at least one side edge surface of the former. In some embodiments, the channel or groove extends around all the side edges of the former/insert.

The retaining formation may be formed on a surface of the former/insert including a moulding texture. Additionally or alternatively, the retaining formation may be formed on an opposite surface of the former or on an edge detail thereof.

The removable member may include an elongate member. The removable member may be flexible or deformable. In some cases the removable member comprises an 0-ring or a piece of rubber material. A width of the elongate member may correspond to a width of at least part of the groove/channel.

The flexible filter may be formed of paper or fabric and may comprise The former may comprise a hydraulic press moulding former/former plate.

The former may comprise a paving slab former, kerbstone former or another product, such as formers for forming counterweights, safety, drainage and/or decorative products. The former may comprise a reusable filter former/insert on a bullnose' of, for example, a kerbstone former/insert, to ensure that the filter is retained around a radi of the kerbstone.

According to another aspect of the invention there is provided a moulding insert/former having at least one surface including at least one retaining arrangement for, in use, retaining a removable member that removably retains a flexible filter over at least part of the surface.

According to yet another aspect of the present invention there is provided a kit including at least one moulding former and at least one removable member substantially described herein and at least one flexible filter.

According to a further aspect of the present invention there is provided a removable member adapted to retain a flexible filter using a retaining arrangement in a moulding former substantially as described herein.

According to another aspect of the present invention there is provided a method of producing moulded products the method including removably retaining a filter in a former using a system substantially as described herein and using the filter with the fitted filter in a moulding press to produce moulded products.

Whilst the invention has been described above, it extends to any inventive combination of features set out above or in the following description.

Although illustrative embodiments of the invention are described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to these precise embodiments. As such, many modifications and variations will be apparent to practitioners skilled in the art.

Furthermore, it is contemplated that a particular feature described either individually or as part of an embodiment can be combined with other individually described features, or parts of other embodiments, even if the other features and embodiments make no mention of the particular feature. Thus, the invention extends to such specific combinations not already described.

The invention may be performed in various ways, and, by way of example only, embodiments thereof will now be described, reference being made to the accompanying drawings in which: Figure 1 is a schematic view of a known hydraulic pressing machine; Figure 2A is an underside view of an example former plate; Figure 2B is a sectional view through line A -A of Figure 2A; Figure 2C details a side edge portion of the plate of Figure 2B; Figure 3A is a plan view of an example filter; Figure 3B is a side view of the filter; Figure 4A is an underside view of the filter fitted around the former plate; Figure 4B is a side view of the filter fitted around the former plate; Figure 40 details a side edge portion of the items in Figure 4B; Figure 5A is a side view of the filter fixed to the former plate by means of a fixing member; Figure 5B details a side edge portion of the items in Figure 5A; Figure 6A is an isometric view of yet another example former plate; Figure 6B details a corner portion of the plate of Figure 6A; Figure 7 is an isometric view of a further example of a filter; Figure 8 is an isometric view of yet another example of a filter; Figure 9A is an isometric view of yet another example of a filter; Figure 9B is a view of the filter of Figure 9A, cut across line A -A; Figure 1 OA is an isometric view of another example former plate, and Figure lOB details a portion of the plate of Figure bA.

Referring to Figures 2A -2C, a first example moulding press former/insert 200 is shown. It will be appreciated that the former/insert is exemplary only and its dimensions, shape (e.g. it could be circular, hexagonal, octagonal or have any irregular outline) and the material from which it is formed can vary. Typically, the former will be formed of strong, rigid material such as steel, plastic, aluminium or the like. The example former has a thickness of around 3 mm -50 mm and, as shown in Figure 2C, its side edges are rounded, although they could be angled or square. The example former is designed to produce kerbstones and includes a matrix of circular blind or through bores/recesses 201 on its upper surface 203. Again, it will be understood that this can vary, e.g. alternative embodiments can have bores that run from the upper surface through to the bottom surface of the former; a riven texture or the like to produce natural-looking paving slabs, or any other surface pattern, writing, logo, etc, for any type of moulded product.

Unlike a conventional former, the illustrated former 200 includes a formation for, in use, removably retaining a flexible filter. In the example, this arrangement comprises a groove 202 formed on the underside of the former.

The square shape of the groove generally follows the outline of outer perimeter of the former. The depth of the groove is around 3.5 mm, its width around 3 mm, and it is located around 5 mm -25 mm away from the perimeter of the former. In other embodiments, the groove may only follow part of the perimeter, or follow it intermittently. The groove may be machined into the surface of the former, or the former may be formed with an integral groove.

Referring to Figures 3A and 3B, an example filter 300 is shown. The filter is formed of flexible material, such as paper, fabric/cloth (woven or knitted) or any other suitable material and be of any shape or form. The example filter is square shaped and is shown in a configuration where its edges 302 have been folded up and over. Its length/width is greater than the length/width of the former 200. This allows it to cover all of the upper surface of the former, as will be described below; however, it will be understood that this may not always be the case.

Figures 4A -4C show how the filter 300 is folded around the edges of the former 200. The upper surface of the former is completely covered by the filter and the edges of the filter cover the sides of the former and are then folded towards the centre of its underside. The folded portions 302 below the underside of the former cover, and extend past, the grooves 202.

Figures 4B and 4C further show a member 401 for, in use, removably retaining the filter 300 in the retaining arrangement 202. The way in which the member is used is illustrated in Figures 5A and 5B. In the example, the member 401 is a flexible 0-ring, formed or rubber or the like. After the filter has been folded over the former as shown in Figures 4A -4C, the 0-ring is pressed into the groove, thereby trapping the filter inside it. The 0-ring may be fitted in this way by hand, tool or by machine, possibly using a jig. Thus, the filter is tightly fitted over the upper surface of the former/insert. Tests have shown that this method of fitting the filter to the former is strong enough to hold the filter in place throughout the hydraulic moulding operation.

When the filter has become less effective due to use, the 0-ring 401 can be removed by pulling it out of the groove 202. Again, this can be done by hand, tool or machine. After the 0-ring has been removed, the filter 300 can be pulled away from the former 104. If desired, the filter can be washed and then re-used by re-attaching to the same, or different, former.

Although an 0-ring has been described in the example above, it will be understood that other types of members can be used to attach the filter to the former. For example, lengths of rigid/solid material, such as a strip of wood or metal, can be used. Such members may or may not have a shape that exactly matches the shape of the groove, although the width of at least part of the member will generally correspond to the width of the groove (or at least the member will be capable of deforming so as to fit into the width of the groove). It is also possible that formations other than a continuous groove can be used to allow the filter to be fixed to the former/insert by means of a removable member.

For example, a set of discrete grooves or recesses could be used, arranged in any suitable pattern, writing, logo, etc over any surface of the former, e.g. parallel lines on opposite sides of the lower surface of the former. In such cases, more than one member may be needed to fit the filter. Once the former/insert has been fixed to the filter, a fixing material such as a tape or any other suitable fixing material (applied via hand, tool and/or machine) may then be used to fix the former/insert-filter assembly and fit it to the hydraulic press to receive a concrete mix/production run, substantially as described above.

The subsequent Figures show alternative arrangements for allowing a filter to be removably fixed to a former/insert by means of a removable member.

Figures 6A and 6B show a former 600 having retaining arrangement in the form of a groove 602 that extends all the way around its four side edges instead of on its upper or lower surface. It will be understood that in an alternative embodiment, the groove 602 may only be present on some of the side edges, e.g. on two opposed side edges.

Figure 7 shows a pre-formed filter fabric 700 having a central square area 702, with four edge lips 704 surrounding it. The lips extend outwardly from folded edges 706.

Figure 8 shows a pre-formed filter fabric 800 having four side edges 802 that have been folded to extend upwardly from a central region 804 from edge fold lines 806. The four edges are angled towards the centre of the former (and so can be thought of as the base of a truncated pyramid).

Figures 9A and 9B show another pre-formed filter fabric 900. Here, the side edges of the filter fabric are folded upwards and back towards the centre of the main flat surface of the former, forming a square U-shape, defined by a short, straight upright section 902 and a perpendicular (and relatively longer) horizontal section 904.

Figures 1OA and lOB show another former 1000. This includes a shod, straight upright wall 1002 and a perpendicular (and relatively longer) horizontal wall 1004. The horizontal wall includes a U-shaped channel/groove 1006, spaced apart from its inner edge, which can accommodate a removable member for fixing the filter in position. In alternative embodiments, the groove 1006 may only be present on some of the horizontal walls (e.g. an opposed pair), or a formation other than a U-shaped groove may be used.

The system described herein allows a filter to be conveniently and removably fitted to press mould former plate (although it will be understood that it can be used with other types of moulding apparatus and/or for forming products other than slabs/kerbstones, using different materials, e.g. plastics, plaster, wood, etc). The components of the system are cheap and easy to manufacture and the system can reduce waste and costs. In some cases, waste reduction is around 50%, as the plastic backer can be removed and replaced with a reusable filter base/insert/former.

Claims

CLAIMS1 A system adapted to removably retain a flexible filter over a least part of a surface of a moulding former or inset, the system including: a moulding former (200) or insert having at least one surface (203) including at least one retaining formation (202) for, in use, retaining part of a flexible filter (300), and a removable member (401) for, in use, removably retaining the flexible filter in the retaining formation.
2. A system according to claim 1, wherein the retaining formation includes a channel (202), groove or shaped slot extending along at least part of the surface (203).
3. A system according to claim 2, wherein the channel (202), groove or shaped slot is substantially straight.
4. A system according to claim 2 or 3, wherein the channel (202), groove or shaped slot extends from one side edge of the surface (203) to another edge of the surface.
5. A system according to claim 5, wherein the channel (202) or groove extends from one side edge of the surface (203) to an opposite side edge of the surface.
6. A system according to any one of claims 2 to 5, including pair of said grooves (202) or channels formed in the surface (203), the pair being spaced apart.
7. A system according to claim 2, wherein the groove (202) or channel follows at least part of a perimeter of the surface (203) and is spaced apart from the perimeter.
8. A system according to any one of the preceding claims, wherein the former (1000) or insert has at least one upstanding wall (1002).
9. A system according to claim 8, wherein the upstanding wall (1002) is perpendicular or angled with respect to a main surface of the former or insert (1000).
10. A system according to claim 9, wherein the former (1000) or insert includes a further wall (1004) extending at an angle from the upstanding wall (1002).
11. A system according to claim 10, wherein the retaining formation (1006) is formed in or on the further wall (1004).
12. A system according to claim 11, wherein the retaining formation comprises a continuous channel (1006) running all along an upper surface the further wall (1004).
13. A system according to claim 2, wherein the channel (602), groove or shaped slot is formed in at least one side edge surface of the former (600) or insert.
14. A system according to claim 13, wherein the channel (602), groove or shaped slot extends around all the side edges of the former (600) or insert.
15. A system according to any one of claims 1 to 12, wherein the retaining formation (202) is formed on a surface of the former (200) or insert that includes a moulding texture or pattern.
16. A system according to any one of claims 1 to 12, wherein the retaining formation (202) is formed on a surface of the former or insert opposite to a surface having a moulding texture or pattern.
17. A system according to any one of the preceding claims, wherein the removable member (401) includes an elongate member.
18. A system according to any one of the preceding claims, wherein the removable member (401) is flexible or deformable.
19. A system according to claim 18, wherein the removable member (401) comprises an 0-ring or a piece of rubber material.
20. A system according to any one of the preceding claims, wherein a width of the elongate member (401) corresponds to a width of at least part of the groove/channel (202).
21. A system according to any one of the preceding claims, wherein the flexible filter (300) is formed of paper, or woven fabric or knitted fabric
22. A system according to any one of the preceding claims, wherein the former (200) or insert comprises a hydraulic press (100) moulding former.
23. A system according to any one of the preceding claims, wherein the former (200) or insert comprises a paving slab or kerbstone former.
24. A moulding former (200) or insert having at least one surface (203) including at least one retaining arrangement (202) for, in use, retaining a removable member (401) that removably retains a flexible filter (300) over at least part of a surface of the former or insert.
25. A removable member adapted to retain a flexible filter using a retaining arrangement in a moulding former or insert according to claim 24.
26. A kit including a system according to any one of claims 1 to 23 and at least one flexible filter (300).
27. A method of producing moulded or hydraulically pressed products, the method including removably retaining a filter in a former using a system according to any one of claim 1 to 23, and using the former (200) with the fitted filter (300) in a moulding press (100) to produce moulded products.
28. A system adapted to removably retain a flexible filter over a least part of a surface of a moulding former or insert substantially as described within and/or with reference to the accompanying drawings.
29. A moulding former or insert substantially as described within and/or with reference to the accompanying drawings.