GB2117664A

GB2117664A - A separating element

Info

Publication number: GB2117664A
Application number: GB08306190A
Authority: GB
Inventors: Jurgen Heyde; Thomas Vogt; Heinz Richter; Siegfried Uhlmann; Anton Prade; Herbert Grosse
Original assignee: LUFT und KALTETECHNIK VEB KOM
Current assignee: LUFT und KALTETECHNIK VEB KOM
Priority date: 1982-03-30
Filing date: 1983-03-07
Publication date: 1983-10-19
Also published as: CH658402A5; GB2117664B; GB8306190D0; DE3302471A1

Abstract

A flat pleated filter element for removing dust and water from air in air-conditioning plant comprises a rectangular frame, whose upper and lower sides 3 have clamping strips of zig-zag formation secured thereto, which retain the non-woven filter fabric 1 under vertical tension and constrain it to pleated shape. The fabric may additionally be supported by vertical threads. The frame sides are of channel section, and the lower side 3 may have drainage pipes (1b) to discharge water. Two such elements may be mounted one above the other and connected by C-clips embracing their abutting sides. <IMAGE>

Description

SPECIFICATION A separating element The invention relates to a separating element and a separator incorporating one or more separating elements.

Separators including a filter made from nonwoven material for separating dust and small water droplets from an air stream have proved trustworthy for use in air conditioning. In particular they are advantageous for separating water droplets in air humidifying plants when the quantity of water to be separated is small in comparison to the quantity of air passed through. In the case of very small water droplets, they represent the only known possibility of separation from the air stream. Since the flow velocity of the gas to be treated though the nonwoven material is substantially smaller than the usual gas velocities in an air-conditioning apparatus, the non-woven material is arranged in a known manner zigzag-like over the cross-section of the apparatus.In order to withstand the flow pressure, caused by the pressure drop over the non-woven material, the non-woven material is supported by an expensive supporting frame or cassettee. Because of its laminar structure the supporting frame causes the formation of an undesirable, additional pressure loss throughout the separator.

If the separator is also to be suited for the separation of fine water droplets from an air stream, the supporting frame has to precisely mated with the wall of the apparatus. This is disadvantageous as it requires a high precision finish which is problematic since the supporting frame should have as small a surface as possible because of the undesirable pressure loss. Furthermore, the separated water has to be removed, which as is known has been achieved by means of horizontally arranged return surfaces, which also cause a blocking of the free cross-section, (see WP 124,836 droplet separator). In order to guarantee the necessary operating safety of the separator, the active separator surface must be arranged at an acute angle to the axis of the apparatus, which requires a large overall length in the direction of flow of the separator.

In embodiments in which the separator is installed upright or only slightly inclined, the separator height has to be limited since an increase in the separator height causes an increase in the quantity of water to be discharged from the non-woven material in the lower region of the separator and this causes the air discharge surface to be reduced and the flow velocity of the air is increased so that water droplets are carried from the separator with the air.

The purpose of the invention is to enable reliable separation of dust or fine water droplets from a gas stream at a low loss of pressure, small capital investment and short overall length of the separator even when a greater height of the droplet separator is required as a result of a large air throughput or geometric considerations. Furthermore, it is intended to achieve a high degree of serviceability and to significantly lower the servicing costs of the separator.

It is the object of the invention to arrange the non-woven material overthecross-section in such a way that it is self supporting, i.e. it withstands the flow pressure without an additional supporting frame. It is a further object to provide a separator which provides a seal with the walls of the apparatus. It is a further object to provide a seperator which ensures the reliable discharge of the separated water. The invention enables a separator to be built which, while having a small overall length, is inexpensive to manufacture and operates at full capacity.

The object of the invention furthermore is to build the separator from several individual separator elements without at the same time increasing the length of the separator in the direction of flow, and to collect the separated water in each individual element and to drain away the water so that the individual element arranged beneath is not subjected to this water, since this would cause the droplets to become ruptured.

According to the invention there is provided a separating element including a filter of sheet mate rial for separating dust and small droplets from a gas stream, the filter being secured to and extending across a surrounding frame, clamping means for securing opposite edges of the filter to a pair of opposed frame elements so that the filter is placed under tension, the clamping means being arranged to arrange the filter in a zigzag fashion which, in use, is arranged substantially vertically.

The filter is preferably made from a non-woven material and is framed by metal or other suitable material on at least two sides. By means of material overlapping at the framing point or by means of additionally introduced material (preferably of the same type as used for the filter), precise sealing is achieved with respect to the apparatus wall of the separator. The separating material itself effects the sealing at those walls which do not have clamping means, for example by having a shape emboseed upon it by the holding elements, in such a way that it lies flush against the walls. This resting flush against the walls is additionally aided by the airstream present during operation.Furthermore, through the arrangement and design of the holding elements according to the invention, the separating material can have a shape embossed upon it which will reduce to a minimum the flow resistance with respect to the area reached and required. The gas charged with dust or water droplets flows through the separating material, causing the charging materials to be separated. The dynamic effect created by the flow resistance is compensated by the residual tension in the separating material, thereby making an additional support structure superfluous. In the case of exceptionally large surfaces to be covered, the dynamic effect of the residual tension can be assisted in the longitudinal and transverse directions by individual elements, for example threads.The non-woven material itself or additional sealing strips prevent unfiltered flow between the separating material and the wall of the apparatus.

Advantageously, the clamping means are constructed to be releasable so that only the material itself cna be exchanged when fully saturated or clogged while keeping the structure of the housing unchanged.

Preferably, at least the lower side of each frame is bent inwardly in U-shaped manner in order to collect the water. The water discharge takes place via one or more drillings in the base or in the arms of the U-shaped lower stays of the frame to which preferably small pipes are attached in a suitable manner and which conduct the water in such a way that the non-woven material arranged beneath the collecting channel is not subjected to this water.

For achieving a compact separator over the entire height, the individual frames are placed one above the other and joined together in a suitable manner, preferably by means of snap-fasteners comprising clasps or clamps, thus creating a vertical tension force component which at the same time generates a sealing effect between the connected frames.

Reference is now made to the accompanying drawings, in which: Figure 1 is a three-dimensional view of a separator element with non-woven material stretched over the cross-section in zigzag-like manner; Figure 2 is an enlarged sectional view taken along line A-A in Figure 1; Figure 3 is a view similar to Figure 2 showing a modification; Figure 4 is a sectional view taken along line B-B in Figure 1; Figure 5 is an enlarged view of a detail of the separator according to Figure 1 as viewed from the side facing away from the direction of flow; Figure 6 is a perspective view of two intercon nected individual separator elements; Figure 7 is a sectional view taken along the line B-B in Figure 6; Figure 8 is a sectional view taken along line A-A in Figure 6.

According to Figure 1 the separator element consists of non-woven material 1 which under residual tension is stretched between the frame parts 3 of the frame 2. The flow direction of the gas to be treated is indicated by an arrow. As shown in Figure 2, the non-woven material 1 is retained in clamping strips 7 and an additional sealing strip 6.

The length of non-woven material 1 is shorter by a certain amount than the distance between the frame parts 3 of the separator. By utilising the elasticity of the non-woven material 1, the non-woven material 1 held first in the clamping strips 7, is secured to the frame parts 3 for example by means of rivet 8. By folding the clamping strips 7 preferably in a zigzaglike manner, which is shown in Figure 4, the required separator surface is produced in the restricted housing of the separator. The folding points 9 and the residual tension gives the non-woven material 1 the strength which is necessary in order to withstand the flow pressure of the gas stream exerted in the direction indicated by the arrow. The clamping strips 7 advantageously are folded in such a way that a larger surface is produced vertically to the direction of flow in the direction of the arrow.When subjected to the pressure of the current flow, this arrangement prevents the surfaces between the folding points 9 from contacting each other, which would contribute to an increased loss in pressure. According to Figure 3, it is also possible to releasably secure the clamping strip 7 in the frame parts 3. For this purpose the clamping strips are provided with slots 11 having approximately the width of the rivet 8, through which they are locked in place beneath the heads of the rivet 8 which additionally has discs 10.

The sealing between the separating material and the wall of the apparatus in the direction of the frame parts 3, in a manner not shown, is effected by the non-woven material 1 itself, or, according to Figures 2 and 3, by an additional sealing strip 6 inserted in a clamping strip 7. The sealing with respect to the fixed frame 2 according to Figure 4 is effected in such a manner that the vicinity of the side walls the clamping strips 7 are bent over in such a way that the non-woven material 1 rests flush againsttheside walls of the frame 2. If large distances between the frame parts 3 are to be covered with stretched non-woven material 1,threads 12 which increase the stiffness of the non-woven material 1 are stretched between the frame parts 3, preferably on the outflow side of the non-woven material 1, as shown in Figure 5.As indicated in Figure 4, it is partiularly advantageous to stretch the threads 12 in those corners which are formed by the dividing surfaces 4 of the non-woven material 1 extending vertically to the direction of flow and the folding points 9. Perlon (Registered Trade Mark) is a suitable material for the threads 12.

It is undesirable to pierce the non-woven material 1 during the separation of liquid droplets. In a manner not shown, the threads 12 are retained, advantageously for finishing, in the frame parts 3 by means of loops into which short cross-members are inserted. For limiting the number of threads 12, it is desirable to provide these with one or more self clamping spacers 5, as shown in Figure 5.

In a further embodiment example according to Figure 6, 7 and 8, the non-woven mat 1 of the upper separator element is held in a frame 2 the frame part 3 of which is curved inwardly in a U-shaped manner as seen in Figure 7. The air charged with liquid droplets flows through in the direction of the arrow through the non-woven mat 1, which retains the liquid droplets. Through the force of gravity these droplets pass downwards through the non-woven mat 1 and are collected in the U-shaped frame part 3 of the frame 2. They are then discharged through the small pipes 5 (Figure 8) to which tubes can be connected for further discharge, not shown in Figure 8. As seen in Figure 7 the joining of the upper frame 2 with the lower frame 2, which contains the non-woven mat 1 is effected by the snap-fasteners 13 which at the same time exert a vertical tensional force component 16 on the frames 2 for achieving a sealing effect between both frames 2. For improved sealing, a sealing material 14, for which preferably non-woven material is used, is arranged between the frames 2 as shown in Figure 6. The upper frame part 3 of the lower frame 2 is also constructed in a U-shaped manner for attaching the snap-fasteners 13.

The invention has the following technical and economic advantages: manufacturing costs are relatively low as a result of the small cost in materials and reduction in the number of individual components; energy consumption required is reduced because of the low pressure losses; small overall length allows a shortening of the units for the air-conditioning plant in which the separator is used and thus leads to a saving of space; improvement of the water discharge and the efficiency of the separator when the same is of substantial height; the use of uniform elements enables economic manufacture and offers good maintenance.

Claims

1. A separating element including a filter of sheet material for separating dust and small water droplets from a gas stream, the filter being secured to and extending across a surrounding frame, clamping means for securing opposite edges of the filter to a pair of opposed frame elements so that the filter is placed under tension, the clamping means being arranged to arrange the filter in a zigzag fashion which, in use, is arranged substantially vertically.

2. A separating element according to Claim 1 wherein at least the lowermost one of said pair of frame elements has upstanding side flanges to define a generally U-shaped cross-section for collecting droplets separated by said filter.

3. A separating element according to Claim 2 wherein the lowermost frame element is provided with a drainage pipe.

A separating element according to Claim 2 or 3 wherein the uppermost frame element is generally U-shaped in cross-section.

5. A separating element to Claim 1,2,3 or 4 wherein the clamping means associated with each one of said pair of frame elements comprise clamping strips each including a bent arm for receiving the filter.

6. A separating element according to Claim 5 wherein the clamping strips are fixedly secured to the associated frame element.

7. A separating element according to Claim 5 wherein the clamping strips are detachably secured to the associated frame element.

8. A separating element according to any preceding Claim wherein reinforcement threads are provided in the region of the folds creating the zigzag formation, the reinforcement threads being located on the downstream side of the filter.

9. A separating element according to Claim 8 wherein spacers are provided between adjacent reinforcement threads.

10. A separating element substantially as described and illustrated in any of the accompanying drawings.

11. A separator including one or more separating elements according to any preceding Claim.

12. Aseparator according to Claim 11 including two separating elements secured to one another with the lowermost frame element of one separating element in abutment with the uppermost frame element of the other separating element.

13. A separator according to Claim 12 wherein a seal is interposed between the abutting lowermost and uppermost frame elements.