GB2212740A - Gas filter - Google Patents

Description

1 APPARATUS FOR CLEANING SOLIDS-LADEN GAS STREAMS 2212740

The apparatus f or cleaning gas streams that are laden with solid matter is utilized in the field of air filtration and dust-separation engineering, and is employed primarily for separating fibres,;iood dust, cereal rubbings or similar types of light or voluminous dust from streams of gas or air.

In certain known apparatuses, different types of fibre or other types of dust are separated-out individually, in a plurality of units. Apparatuses of this type are, in the main, installed upstream of secondary, fine cleaning stages, and are erected on their own. They require large quantities of material, occupy much space, and are capable of separatingout only one type of material at a time. Furthermore, there are certain known apparatuses wherein separation is effected on rotating filter discs, and these discs may, if appropriate, be divided into a plurality of sections which are cleaned off by means of slot nozzles, and which are mostly connected directly to a secondary, fine cleaning stage. These apparatuses have the disadvantage that it is impossible to locate an. inspection and maintenance space between the primary, precleaning stage and the secondary, fine cleaning stage, while the pressure loss 4 2 associated with the f ilter discs results in the occurrence of thrust forces on the rotating structural elements, thus giving rise to problems concerning wear and sealing between the rotating elements and the stationary ones, while in addition perfect separation, correctly adapted to each of the different types of solid matter, does not occur when division into sections is practised.

The object- of the invention is to provide an apparatus which,compared to the solutions known until now, is spacesaving and economical in the use of materials, this being an apparatus which can be manufactured at low cost, which is of simple construction, and which operates reliably.

The object of the invention is to provide an apparatus for cleaning one or more solids-laden gas streams within one constructional unit, each gas stream being laden with a different type of solid matter, this apparatus containing no moving structural elements, being suitable for installation as a separately located apparatus system, being capable of combination with secondary, fine cleaning apparatuses, should these be required, and making it possible to perform appropriate inspection and maintenance tasks between the two separation stages-.

f 1 h t 3 According to the invention, this object is achieved by means of the features specified in the Claims, in that one end of a rectangular easing is tautly covered with a filter cloth or a similar porous, air-permeable material, and one or more inlet ducts for supplying the solids-laden gas streams are located on one of the four side surfaces. Corresponding to the number of gas streams that are to be cleaned, or rather to the number of inlet ducts, the rectangular easing is divided into sections with appropriate filter areas, and suction extract slots for acquiring and discharging the solids that are deposited on the filter surface are allocated in an arrangement corresponding to the inlet ducts on the opposite side surface. One or more guide devices, depending on the length of the filter surface, are fixed transversely to the inflow direction, in which they are inclined, these guide devices leaving an unobstructed flow cross-section on the side facing the filter cloth. if the operating conditions (gas flow rates) are variable. at least that guide device which is nearest the inlet duct should be adjustable by shifting.

1 The solids are deposited as the gas stream passes through the filter surfaces. Continuous regeneration of the filter surfaces is achieved through the agency of a floi, component which the guide devices constrain to run parallel 4 to them. This deliberately generated velocity component diminishes in the direction of the suction extract slots, and its exploitation enables the filter cloth to be "blown clean". The solids are conveyed towards the suction extract slots, near which they are acquired and discharged.

Furthermore, the guide devices ensure that thegas stream that is to be cleaned passes through the filter cloth at a velocity which is virtually constant over the entire area. The minimization of the space and materials requirements is based on the fact that different types of solid matter are separated from the corresponding gas streams within a single apparatus. The forced utilization of specific flow components for regenerating the filter cloth eliminates moving structural elements, reduces wear, and substantially increases the reliability. In the event of its being combined with an internal admission drum-type dust filter, for example, the apparatus according to the invention is adapted to fit the connection casing of the drum-type filter. Inspection and maintenance tasks are then performed via the connection easing doors, without difficulty. This installation arrangement completely eliminates thrust forces of the kind which occur in systems employing known rotating filter discs, and which can be transmitted to drum-type dust filters.

t C> d Figures 1 and 2 de-pict an illustrative embodiment of the apparatus for cleaning solids-laden gas streams 1, this embodiment taking the form of a combination with a drum-type dust filter 2 and its connection casing 3. The rectangular casing is divided into sections 4, corresponding to the gas streams that being tautly are to be cleaned, the ends of these sections covered with filter cloth 5. the solids-laden gas streams enter the sections 4 via the connection ducts 6 on the side surfaces, and are directed against the filter cloth 5 by the guide devices 7, 8 and 9. A portion of the gas stream passes through the f ilter cloth 5 so that the solids are deposited thereon. The solids that are deposited on the filter cloth 5 are transported, acquired and discharged through the agency of a velocity component of the particular gas stream that is to be cleaned, this velocity component being constrained to occur in the direction towards the suction extract slot 10, which are located opposite and corresponding to the inlet ducts 6. The guide device 7, i.e. the one nearest the inlet duct, is installed in a manner such that it can be adjusted by shifting, thus enabling the flow cross-section 11 - and hence the flow velocity - to be adjusted to suit the gas stream that is to be cleaned. In the illustrative embodiment, the cleaned gas streams are brought together and led to a drum-type dust filter 2 for secondary, fine cleaning. As depicted in i 6 31 Figure 1, the apparatus 1 shows a possible design for three gas streams, each laden with a different type of solid matter, these streams being ducted-in from the upper side surface via one straight duct and two curved ducts.

As depicted in Figure 2, the apparatus 1 shows a possible design for two gas streams, each laden with a different type of solid matter, one stream being ducted-in from the left-hand side surface via a straight duct, and the other being ducted-in from the right-hand side surface via a curved duct.

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Claims (5)

1 Apparatus. for cleaning solids-laden gas streams, each stream being laden with a different type of solid matter, the apparatus including a easing having an open end tautly covered by a filter cloth, the easing being divided into sections extending across the filter cloth, one section being provided for each stream, each section including at least one inlet duct at one end and at least one suction extract slot at its opposite end such that the stream flowing through the section is caused to flow in a direction transversely across one face of the filter cloth, each section including at least one guide located to guide the stream into contact with the filter and create a velocity component for transporting solid material deposited on the filter cloth to said at least one suction extract slot.

2. Apparatus according to Claim 1 wherein each section includes an adjustable guide located adjacent to said at least one inlet duct, the adjustable guide being capable of adjusting the flow cross-section of the stream entering the section.

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3. Apparatus according to claim 1 or 2 wherein a drum type dust filter is attached to said easing such that the cleaned gas streams passing through the filter enter the drum -type dust filter for secondary cleaning.

4. Apparatus for cleaning solids-laden gas streams, each stream being laden with a different type of solid matter, characterized in that one end of a rectangular casing is tautly covered with a filter cloth, one or more inlet ducts for the solids-laden gas streams are located on one of the side surfaces, and suction extract slots for discharging the deposited solids are located on the opposite side surface, in an arrangement corresponding to the inlet ducts, in that, corresponding to the number of inlet ducts, the rectangular easing is divided into sections, and in that guide devices are fixed transversely to the inflow direction. in which they are inclined, these ouide devices leaving an -ed flow cross-section on the side facing the unobstruct filter cloth.

5. Apparatus according to Claim 4, characterized in that at least one guide device is installed in a manner such that it can be adjusted by shifting.

Published 1989 at The Patent Office, State House. 6671 HI9hHolborn. LondonWClR4TP. Further copies maybe obtained frorn The Patentoffice Sales Branch, St Mary Cray, Orpington, Rent BR5 3RD. Printed by Multiplex tecbxuques ltd. St Mary Cray, Kent, Con. 1/87 1 Q