WO1994014522A1

WO1994014522A1 - Filter element

Info

Publication number: WO1994014522A1
Application number: PCT/GB1993/002619
Authority: WO
Inventors: Joachim Rebmann
Original assignee: Scapa Group Plc
Priority date: 1992-12-22
Filing date: 1993-12-21
Publication date: 1994-07-07
Also published as: DE4336671A1; AU5819494A; EP0646039A1; DE9217529U1

Abstract

A filter element for the filtration of dust particles from gaseous media having two concentrically arranged cylindrical filter bodies (1, 2) each comprising two fluted filter cylinders (4, 5) arranged so as to provide a plurality of canals (6). The gas is filtered through the filter cylinders (4, 5) and exhausted via the canals (6). The lower ends of the filter bodies are sealed.

Description

FILTER ELEMENT

The present invention relates to a filter element for the filtration of dust particles from gaseous media.

EP 490662 describes a filter element comprising several co-axially arranged carriers in each of which is contained a filter body so as to increase the effective filtration area, whereby the carrier and filter element are arranged such that the exhaust air channels completely cover the filter element, running in the lengthways direction. Prior art filter sleeves generally comprise a synthetic needled batt, whereby the opposing parts of both filter sleeves are joined to each other, thereby forming exhaust air channels. Prior art filter sleeves generally comprise a needled batt, particularly one comprising synthetic fibres, which may be coated with a suitable permeable material on each pressure side so as to raise the resistance to corrosion. The said prior art filter elements have the major disadvantage that the butting on of the individual elements results in a relatively long construction length, if the desired filter area is to be obtained. As well as the disadvantage of the long construction length and the associated difficulty of placing such long filter elements in filter devices, a further more worrying disadvantage is the insufficient cleaning effectiveness. Normally such filters are cleaned by passing pulses of compressed air along the exhaust air channels in order to shake off dust particles adhering' to the pressure sides of the filter. It has been shown that with such filters the pressure drop for the first element is so great that increasingly the pressure is insufficient for removing dust particles from subsequent elements. The aim of the invention is to provide a filter element having a simpler and more condensed construction and short construction length whilst retaining a high filtration capacity and allowing simple and regular cleaning of all applicable filter bodies or sleeves.

According to the present invention there is provided a filter element for the filtration of particles from gaseous media, the filter element having cylindrical filter bodies each comprising at least two wave-like folded filter cylinders arranged such that a plurality of filtered gas exhaust channels are formed in between the said filter cylinders, the gas media to be filtered being initially directed along the other side of the filter cylinders outside the channels, wherein each filter body is contained in a carrier, the said channels flowing through the carrier and the carrier sealing an air inlet space between the filter bodies, and wherein the filter element comprises at least two concentrically arranged filter bodies contained in carriers and the lower ends of each filter body is sealed. Preferably the lower ends of the filter body are sealed by an optionally circular sealing body.

The concentric arrangement of the filter bodies in their filter sleeves enable a high filtration capacity to be obtained without increasing the body length of the filter element, as a result of the large filtration area. If the exterior dimensions of the filter element correspond to the normal measurements, the filter element according to the invention may additionally be built into existing devices, whereby the filtration can be significantly increased without the need for further alterations. The concentricity of the arrangement of the filter elements enables the impure medium to be introduced by a simple method and for the exhaust air to be removed simply in a concentric manner, by the same carrier. In the compact and sealed form each filter element contains a complete filter body, the lower end of each element being sealed by a sealing body and the purified exhaust air removed from the carrier via its exhaust air channels. At the same time the filter element may be cleaned by a simple and problem free process with the aid of the previously mentioned compressed air method. The compressed air pulses may be led over the carrier via the exhaust air channels. The distance that each pulse of air has to be travel is equally long on each filter element so that a different pressure drop for the compressed air within the exhaust air channels of the individual filter bodies is avoided. The filter element according to the invention is simple to prepare. The filter body with its filter sleeves are prefabricated, and then inserted into the carrier which is sealed with a sealing body. Due to the increased filtration capacity not requiring alterations in the exterior dimensions, the construction is simple, even for the conversion of existing devices or equipment. Preferably the ends of at least one of said filter bodies and the filter cylinders thereof are embedded in gas-tight fashion in the carriers or a sealing body for sealing the lower ends of the said filter body. The carriers and sealing body are preferably made from synthetic material. The prefabricated filter sleeves or bodies are each incorporated in suitably gas-tight form into the carriers or sealing body, e.g. by moulding.

Preferably the filter element comprises at least one ring for the carrier or outermost filter body and at least one disc body supporting the innermost filter body and located in the ring body in a gas tight fashion. Here the individual filter bodies may be simply prefabricated with a circular or disc-shaped body and then inserted gas-tight into one another.

Preferably the disc body has a flange turned to the outer side of the carrier operable to be disposed in a corresponding receptor groove provided in the ring body. More preferably the disc body has harness support in the innermost filter body. Here the mounting and strength of the innermost filter body provides a compact construction unit. For most areas of use the carriers have a flush outer side along which extend the filtered air exhaust channels of the filter body extending along said smooth outer sides.

In order for the cleaning of the filter element to be simple and effective, there is provided a sealable nozzle body with concentric cylindrical compressed air channels all flowing over the exhaust air channels of the filter body is disposed on the carriers. In order that the invention may be more readily understood a specific embodiment thereof will now be described by way of example only with reference to the accompanying drawings in which:-

Fig.l is a side view of a filter element according to the invention, partially represented as a longitudinal section, and

Fig.2 is a cross section along the line A-A in Fig. 1.

The diagrams show a schematic representation of the filter element, whereby in Fig.2 the imagined cylindrical marking of the filter body or sleeve is marked by a circle, although the filter body or sleeve is shown with no outer cover, rather it is depicted as a pleated area facing the impure medium. Referring to the drawings, two filter bodies 1 and 2 with a cylindrical shape, arranged concentrically to each other are outlined within one disc-shaped carrier 3. Filter bodies 1 and <2 comprise (as particularly represented in Fig.2) two wave-like pleated filter sleeves 4 and 5 having peaks of pleating. Each outward-facing area of the filter sleeve is facing the impure medium. On each inner side of the filter sleeves 4 and 5 are located the individual exhaust gas channels 6, in this case having a rhombic-shaped cross-section. A circular space 7, is located between both filter bodies 1 and 2, sealed from above by a carrier 3 but left open below. The impure medium flows onto the filter element and into the circular space 7, striking the inner area of filter bodies 1 and 2.

The exhaust gas channels 6 for both filter bodies 1 and 2 continue into the carrier 3. At their lower ends both filter bodies are sealed by a circular sealing body, of which only the sealing body 8 for filter body 1 is visible in Fig. 1. A corresponding circular sealing body also blocks the exhaust gas channels 6 on the inner filter body 2.

The carrier 3 and sealing body 8, as well as the sealing body for the inner filter body 2 preferably comprise a synthetic material, and each of the ends of filter bodies 1 and 2 are incorporated in a gas-tight fashion onto the synthetic material carrier 3 or sealing body 8.

As shown in Fig.l, carrier 3 comprises a circular body 9 and the outer filter body 1 and a middle disc body 10 supporting the inner filter body 2. The disc body 10 is inserted into circular body 9, is gas-tight and removable. This is possible to attain easily with the appropriate forming and choice of the synthetic material.

The disc body 10 is provided with supporting flange 11 facing the outer side of carrier 3, the flange being placed in a corresponding open circular area 12 of the circular body 9, so as to give a safer support and increased gas-tightness. In addition the disc body 10 is provided with harness supports 13 in the inner filter body 2. As shown in Fig.l, components 9 and 10 form the smooth outer side of carrier 3, along which flow the exhaust air channels 6 for filter bodies Al and 2.

As shown in Fig.l, the filter element is further characterised by the provision of an air-tight sealable nozzle body 14 on the carrier 3, correspondingly rotationally symmetric to the arrangement and dimension of carrier 3. This nozzle body is provided with concentric circular compressed air channels 15, each flowing over the exhaust air channels 6 of filter bodies 1 and 2.

It is to be understood that the above embodiment described herein is by way of example only. Many modifications and variations are possible.

In the example, simply two concentric filter bodies 1 and 2 are provided in the filter element. However, the same construction may contain more than two filter bodies.

Claims

1. A filter element for the filtration of particles from gaseous media, the filter element having cylindrical filter bodies each comprising two wave-like folded filter cylinders arranged such that a plurality of filtered gas exhaust channels are formed in between the said filter cylinders, the gas media to be filtered being initially directed along the other side of the filter cylinders outside the channels, wherein each filter body is contained in a carrier, the said channels flowing through the carrier and the carrier sealing an air inlet space between the filter bodies, and wherein the filter element comprises at least two concentrically arranged filter bodies contained in carriers and the lower ends of each filter body is sealed.

2. A filter element as claimed in claim 1, characterised in that the ends of at least one of said filter bodies and the filter cylinders thereof are embedded in gas-tight fashion in the carriers or a sealing body for sealing the lower ends of the said filter body.

3. A filter element as claimed in claim 1 or claim 2, characterised in that the filter element comprises at least one ring for the carrier or outermost filter body and at least one disc body supporting the innermost filter body and located in and removable from the ring body in a gas tight fashion.

4. A filter element as claimed in claim 3, characterised in that the disc body has a flange turned to the outer side of the carrier operable to be disposed in a corresponding receptor groove provided in the ring body.

5. A filter element as claimed in claim 3 or claim 4, characterised in that the disc body has a harness support in the innermost filter body.

6. A filter element as claimed in claim 1 or claim 5, characterised in that the carriers have a flush outer side the air channels of the filter body extending to be flush with the outer sides.

7. A filter element as claimed in any of claims 1 to 6, characterised in that a sealable nozzle body with concentric cylindrical compressed air channels all flowing over the filtered gas exhaust channels of the filter body is disposed on the carriers.