JPH055526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a method for holding successive folds, or accordion-folded folds, of high-efficiency air filter media a predetermined distance apart. Regarding the generally used type of tapered corrugated spacer member, in particular, a new type of spacer member which is folded in a zigzag manner along parallel lines and has a larger number of V-shaped portions over a certain width at one end edge of the sheet than before. This invention relates to a spacer member having a shape.

(Technical Background of the Invention and Problems Thereof) In general commercially available high-efficiency air filters, the filter medium is folded into an accordion shape to form a continuous V-shaped folded body, and the outer circumference is sealed to an open rectangular frame. The distance between the surfaces of adjacent bent bodies is 0.2 at the open end.
The maximum value is less than an inch (approximately 5 mm), and the bent bodies gradually merge toward the closed end. As a result, it is necessary to place spacer means between adjacent walls of each medium in order to maximize the volume of airflow through the filter and minimize the pressure drop to meet the required efficiency level.

In such filters, corrugated sheets of aluminum or other materials tapered from one edge to the other have been used for many years to provide the required spacing between the media folds. It has been used for a long time. For example, U.S. Pat.
Similar disclosures are found in US Pat. No. 3,146,197 and Barany U.S. Pat. No. 3,293,833. The present invention is most closely related to the latter patent, and relates to an improvement that reduces the degree of taper and reduces the amplitude, as described below.

The amplitude ratio, that is, V passing through the continuous bending line on each side
The straight line distance between parallel lines extending in the lateral direction of the spacer member along the two edges forming the character-shaped portion is:
It is the same as the ratio of the number of V-shaped parts within a certain width on both ends. In other words, when forming three V-shaped parts on one end edge corresponding to each V-shaped part on the other end edge, the height of the edge with a small amplitude is adjusted to keep the folded lines parallel. will be one third of the height on the large amplitude side. Similarly, if five V-shaped parts are formed on the small-amplitude side edge corresponding to one V-shaped part on the large-amplitude side edge, the ratio of both amplitudes and the V-shaped part within a certain linear distance The number of glyphs is 5:1.

5:1 in such type of tapered separator
It has long been recognized that a ratio of 3 to 1 is useful, and Barany's U.S. Pat.
No. 3,293,833 mentions that the ratio is preferably any odd number. However, it has been virtually impossible to manufacture suitable spacers with shaping rollers and blades having a ratio greater than 3 to 1 as disclosed in that patent. That is, as suggested by commonly assigned U.S. Pat. No. 3,293,833 and related U.S. Pat. No. 3,311,526, which includes a preferred embodiment of a spacer manufacturing apparatus, the number of small amplitude molded blades on each side of a large amplitude blade may be reduced. It is possible to change this ratio by simply increasing it, but attempting this in manufacturing a spacer with large amplitude bends over the required size range would result in numerous fractures and fractures along the small amplitude side edges. A crack occurred. Such fractured or cracked spacers cannot be used because the jagged sharp edges tear or puncture the filter media, rendering the entire filter assembly unacceptable.

Furthermore, in order to provide a spacer with the required stiffness and resistance to flattening after forming the V-shaped portion, an aluminum material having the minimum necessary hardness to cause virtually no fracture or cracking in the formed spacer is used. It is preferable to use a sheet. Conventionally, it has been considered inappropriate to manufacture spacers with a 5:1 taper ratio, even when using soft aluminum that can be stretched without fracture.

It is desirable that the amplitude ratio of the spacer be increased from the high side end to the low side end, and it is also desirable that the taper be as uniform as possible from one side to the other side. The V-shaped portion extending over the entire spacer from one end to the other, that is, the folded line included in the large-amplitude side edge forms such a gentle taper, while the intermediate V-shaped portion at the small-amplitude side edge forms such a gentle taper. The fold lines forming the section do not extend completely to the large amplitude side edge even when the large amplitude V-shaped section continues. In the end, in order to maximize equalization and make the taper gentler, the folding line forming the intermediate folding curve should be extended to a portion corresponding to approximately 90% of the distance between the small amplitude edge and the large amplitude edge on the small amplitude edge side. It needs to be extended.

The spacer disclosed in the above-mentioned U.S. Pat. No. 3,293,833, particularly in FIG.
However, in the case of spacers that have actually been provided on the market over the past 20 years, the intermediate bending curve is approximately 30% longer than the distance between the small amplitude side edge and the large amplitude side edge. It was not possible to obtain a shape extending over 50% or more.

Therefore, in the corrugated aluminum spacer,
It has long been recognized that it is useful and desirable to taper the amplitude at one end to a desired amplitude while reducing the amplitude at the other end by about a factor of five. However, no suitable spacer of this type has ever been manufactured on a commercial scale by passing an aluminum sheet between the forming blades of a pair of rotating rollers, and then interlocking and folding the sheets. . or,
Conventionally, in actual machines, it has not been possible to obtain a desired high-hardness spacer and an intermediate fold curve that extends from the small amplitude side edge to the large amplitude side edge over about 90% of the distance between the former edge.

(Object of the Invention) The main object of the present invention is to maintain the continuous pleats at a distance from both the upstream and downstream open ends, and to provide a more angular shape from the open end to the closed end than similar prior art. It is an object of the present invention to provide a wave-shaped spacer for use in a high-efficiency air filter of the type made of an accordion-shaped folded medium, which has a more uniform taper leading to the ivy fold.

Another main object of the present invention is to provide a continuous V-shaped portion having a uniform width and amplitude along one edge, and having a width and amplitude substantially equal to the V-shaped portion along the opposite edge.
It is one-fifth of that of the character-shaped part, and the amplitude is 0.03 to
The object of the present invention is to provide a corrugated aluminum sheet product that is folded in a zigzag pattern along substantially parallel fold lines to provide a V-shaped portion on the order of 0.04 inches.

Another object of the present invention is to pass an aluminum sheet between the forming blades of rotating rollers and fold the sheet without a significant number of cracks, tears or breaks after forming, compared to conventional spacers. An object of the present invention is to provide a corrugated aluminum spacer for an accordion-like bent air filter, which is provided with a small-amplitude bend.

Yet another object of the present invention is to have an amplitude ratio of 5:1 from the high end to the low end, such that the folded line forming the intermediate V-shaped portion at the low amplitude end extends the entire distance toward the high amplitude end. The object of the present invention is to provide a zigzag bent spacer of the type mentioned above which has a substantially uniform taper extending over about 90 percent of the length of the spacer.

Other purposes will become apparent from the description below.

SUMMARY OF THE INVENTION In the novel filter structure and spacer configuration of the present invention, the foregoing objects are achieved by the use of a forming blade of a rotating roller through which an aluminum sheet passes, the blade having a longitudinal edge. one side is highly polished and contacts the sheet to form fold lines therein. A preferred finish for the blade edge is lap sanding to 4 to 8 microinches (approximately 0.101 to 0.204 micrometers), i.e., the surface roughness of the polished area of the blade surface is no more than 4 to 8 microinches. . The aluminum sheet is preferably fed from a continuous roll, initially flat, with two longitudinal edges separated by fold lines substantially parallel to each other and to the other two edges (third and fourth edges). It is formed in a zigzag shape along (the first and second edges). For every zigzag bent portion or V-shaped portion along one edge of the two longitudinal edges, a total of five such V-shaped portions are provided along the other edge. Therefore, the height or amplitude of the V-shaped portion along one edge is five times the height of the V-shaped portion along the other edge. The folding lines forming the V-shaped portion along one edge extend completely to the other edge, and the folding lines forming the four auxiliary V-shaped portions extend from the other edge toward the one edge at both ends. Extends approximately 90 percent of the edge-to-edge distance. The spacer material also has a thickness of about 1 to 2 mils (about 25.4 to 50.8 micrometers), preferably 0.0015 inches (about 38.1 micrometers), and an amplitude of about 0.3 to 0.4 inches (about 7.6 10.2 mm) and a hardness of H19, such as 1145 aluminum.

A spacer having the shape and characteristics described above is disposed successively between each bend of the accordion-shaped folded filter media. The amplitude at the low end of the spacer is three times the amplitude at the high end as in the best prior art.
Because it is only one-fifth of the size rather than one-fifth, the closed end of the media folded around the low-amplitude end of the spacer is less angular than in a conventional filter assembly of the same type. Extends to the bend. or,
The shape of the pleated walls or flanks of the media is made even more flat, which allows the filter media to be flattened while maintaining the filter efficiency and the air flow rate through the filter at the same value compared to conventional filters. can reduce the pressure drop caused by filter ventilation resistance.

(Embodiments of the invention) Hereinafter, embodiments of the invention will be described with reference to the drawings.

In FIG. 1, a filter device or cartridge is indicated generally by the numeral 10 and is representative of the type of high efficiency air filter that has been in widespread commercial use for many years. It is. The filter 10 includes a frame, and the frame includes solid flat side plates 12, 1 made of wood or metal.
4, 16 and 18, forming a box shape with an open end. A continuous sheet of conventional filter medium folded into an accordion shape is sealably disposed within the frame to form a plurality of pleats extending in the front-rear direction across both open ends of the frame. The pleated medium terminates at 20,22.

A pleated side or flank portion designated by the reference numeral 24 extends from the edge 20 to a bent portion 26 and is tightly or sealably fixed to the inner surface of the frame side plate 12. The pleated sides extending from the terminal edge 22 are similarly sealed to the frame side plate 16. The zigzag side edges of the media extending throughout the depth of the filter can be formed in a suitable and effective manner, such as in accordance with the teachings of commonly assigned U.S. Pat. It is sealed to the frame side plates 14 and 18. Such side edges are made of adhesive material and are designated by reference numeral 28,
It is embedded within the adhesive layer indicated by 30.

One or more of the above filter devices are placed within an opening in a wall, ceiling or other solid barrier with suitable airtight sealing means interposed between the filter frame and the filter frame.

Unfiltered air enters the filter from upstream, as indicated by arrow 32, to be filtered, and passes downstream, as indicated by arrow 34. Air flows between the pleats of the filter medium that open on the upstream side, passes through the pleat sides, and flows out between the pleat folds that open on the downstream side. The above is the same as the conventional configuration.

In order to maintain the desired shape of the walls of the pleated media, that is, a shape that gradually tapers from the open end to the closed end, the wave height of the corrugated sheet is increased along one edge of the sheet and decreased at the other end. It has been standard practice in industry for many years to place the sheet between each pleat of the medium. FIG. 1 shows a corrugated sheet constructed as will be described in detail below, which sheet is inserted between upstream-opening pleats indicated at 36 and downstream-opening at 38. It is inserted between the pleats shown. In FIG. 1, the spacer is shown exaggerated in size relative to the overall filter assembly for clarity of construction. In reality, for a filter assembly with a total height of 22.5 inches (approximately 57 cm), 90 to 110 pleats with typical specifications are provided, and each pleat has two pleats, one upstream and the other downstream.
Two spacers are provided. Further, the number of zigzag-shaped bent portions at the edge of one of these spacers having a large wave height is not about 12 as shown in the figure, but is actually about 50.

The structure of the spacer will be described in detail with reference to FIGS. 2 and 3. In the preferred spacer manufacturing method, a continuous strip 40 of flat aluminum sheet is fed between a pair of spaced apart rotating rollers. One roller is designated at 42 in FIG. 2, and both rollers have radially projecting and axially extending shaped blade portions, as will be explained in more detail below. According to the conventional configuration, the sheet ends are formed at edges 48, 50 before being introduced into the forming rollers.
It is folded as shown in the figure, providing a so-called "safe edge." When the aluminum sheet leaves the forming roller, it is folded in a zigzag pattern, with the fold line perpendicular to the sheet transport direction indicated by arrow 44 in FIG. After passing through the rollers, the folded sheet is cut to a required length corresponding to the width dimension of the filter assembly to be used.

As is clear from FIG. 2, both end edges 48, 50
Four auxiliary curves 52 are interposed between the fold lines 46 that extend over the entire length. The folding line 52 extends from the edge 50 toward the edge 48 by approximately the distance between both edges.
It extends for 90% of the distance and converges with the surface of the sheet at its end. The details of the edge 48 of one zigzag bent portion are shown in an enlarged scale in FIG. 3, and the side of the edge 50 is shown superimposed over the same width dimension. In the figure, folding lines 46 appear on both edges, and four folds are formed at each interval of the folding lines 46.
If the two folding lines 52 are on the edge 50 side, the edge 48
Five zigzag-like bends will be provided within the same width dimension as one bend on the side. The linear distance of one entire zigzag bend along edge 48 is indicated by dimension W. On the other hand, the width of one zigzag bent portion along the edge 50 is indicated by w. Further, the heights, that is, the amplitudes of the zigzag bent portions along both end edges 48 and 50 are indicated by dimensions H and h, respectively.

The length of the spacer member over one zigzag-shaped bend along the edge 48, that is, the length measured along the path from the fold line 46 to the fold line 46'' via the fold line 46' in FIG. It is called "length". Importantly, the length of one entire zigzag fold at edge 48 should be exactly the same as the length of five zigzag folds at edge 50 as shown. Therefore, the angles of the bent portions along the two edges are set to be slightly different. For example, the angle A of the large amplitude bend is approximately 110
degree, the angle a of the small amplitude bend is approximately 91 degrees.

The cooperation between the filter medium and the spacer will be clear from FIGS. 4 and 5. First, the air is directed to the high amplitude zigzag bend of the spacer 36 between the media surface upstream of the filter device 10 and the pleats of the media that open upstream of the filter device 36, as shown by arrow 54. flows into the triangular passage between the After passing through the wall of the filter medium, the air exits via a passageway between the medium wall and the spacer 38 opening downstream, as indicated by arrow 56. The filter medium is folded around the spacer at the low amplitude edge 50. The bends of the upstream and downstream media are designated 58 and 60, respectively. As shown in enlarged detail in FIG. 4A, both ends of the bent portion of the medium are provided in a square shape. Note that it has been found that such a shape is preferable compared to an acute bent part. Both height and width are 24 inches (approximately 60 cm)
For a typical filter device with external dimensions of 12 inches (approximately 30 cm) deep, 22.5
Preferably, there are 105 pleats within an inch dimension. Such a filter device has a thickness of approximately 0.015 inch (approximately 0.4 mm) and an external dimension of 3/32 inch (approximately 2.4 mm) at the bent end.
It is preferred to use a filter medium of . As previously mentioned, the amplitude at the lower end of the spacer shown in Figure 4A is 0.03 to 0.04 inches (approximately 0.7 to 1 mm), typically 0.036 inches (approximately 0.9 mm), and this is shown as dimension h in Figure 3. Indicated. Therefore, the external dimension of the filter medium at the bent end is set to be approximately 2.6 times h as shown in FIG. 4A. Since the thickness of the medium at the lower end is approximately half the amplitude of the zigzag bend (0.5h), the space between the medium and both spacers is approximately 1.5h in total at the bent end.
The pleated portion of the medium is in contact with the spacer over a short distance from the bent end.

The forming blade and forming roller will be described in detail with reference to FIGS. 6 to 9. A roller 62 is disposed directly opposite the roller 42 and rotatable about an axis parallel to the roller 62 . roller 42,
62 is identical in all respects and includes a forming blade supported on rollers. The blade is disposed in a groove formed on the outer periphery of the roller parallel to the roller axis to support the blade. Regarding the arrangement of such blades and the rotatable arrangement and driving of rollers, see the aforementioned US Pat. No. 3,311,562. However, in the present invention, the shaped blade is formed into three unique shapes shown separately in Figures 8a, 8b and 8c.

The folding lines formed on the spacer, including the amplitude and period of the folding lines that give the final shape of the spacer, are determined according to the blade shape and the distance between the axes of the rollers. Then, the blade 64 forms a folding line 46 that extends over the entire spacer from one side to the other side. Blades 66 are disposed on each side of blades 64, and two of blades 68 are disposed between each pair of blades 66.
The blades and rollers shown in FIGS. 6 to 9 have a high amplitude dimension H (first value) of 0.165 inches (approximately 4
mm), small amplitude dimension (h) is 0.036 inches (approximately 0.9
mm), angles A and a are 109°33' and 90°20', respectively;
Period W of one V-shaped part at the high amplitude side edge (second
It is designed for use in manufacturing spacers with a value of 0.48 inch (approximately 12 mm) and a period w of 0.090 inch (approximately 2.3 mm) at the edge on the small amplitude side.

In order to form a V-shape with the same amplitude along the edge 50, the three blade shapes have a height at one end (dimensions a1, b1) as shown in FIGS. 7 and 8.
and c1) are all the same and protrude the same distance from the rollers 42, 62. Blade 6 is used to form a high amplitude V-shape along edge 48.
4 is evenly tapered from this height to the larger dimension a2. On the other hand, the blade 66 has a constant height (b1) over about 80 percent of its total length, and tapers to a smaller height b2 over the remaining 20 percent. Further, the blade 68 has a length of approximately
tapered at a small angle (e.g. 0°18') to a smaller height c2 over 80%;
Furthermore, the height c3 is smaller over the remaining 20 percent.
tapered at a large angle (e.g. 1°17'). Then, by giving the blades 66 and 68 a large taper over about 20% of their total length toward the edge on the large amplitude side, the auxiliary curve 52 is assimilated into the sheet surface 12 from the edge 48 over about 10% of the full width of the spacer. can be done. As shown in FIG. 6, the blade 64 of one roller is
The rollers are aligned in the rotational direction so that the rollers are located closest to each other between the two blades 68 of the opposing rollers.

The three blade shapes are all of the same cross-section except that blades 66 and 68 are strongly tapered at one end over 20 percent of the blade length, the preferred shape being shown in FIG.
The blade tapers from the parallel sides as shown at a 45° angle to a 0.010 inch radius with a 3/16 inch radius on each side of the taper. There is a smooth transition to the parallel side at the radius of 4.8 mm). For blades with the above geometry, the preferred diameter of the roller is
It is 2.855 inches (approx. 73mm). The roller has a width (blade thickness) of 0.047 inches (approximately 1.2 inches) along the axial length.
mm) with a depth of 0.177 inches (approximately 4.5 mm). And if the groove spacing is 3°36′
100 grooves will be provided, with 20 blades 64 and 40 blades 66, 68 each held within the grooves. These blades are retained in a known manner by removable end caps, allowing them to be replaced individually in the event of wear or damage. The center distance of the roller is 22.5 inches (approximately 57
spacers of the dimensions shown herein (with a large amplitude value of 0.165 inches (approximately 4
mm), and the small amplitude value is 0.036 inch (approximately 0.9 mm)), it is set to 3.055 inch (approximately 78 mm). By adjusting the center-to-axis distance, the dimensions of the spacer can be varied between slightly larger and slightly smaller amplitudes, suitable for example for filter devices with 90 to 110 filter media folds. Spacers are provided.

An important feature is that all blade surfaces in contact with the aluminum sheet are ground, e.g.
Finished with an accuracy of 0.204 micrometers).
This allows a 1.5 mil (approximately 38 micrometer) thick sheet of acceptable hardness to be approximately 0.035 mm thick without cracking or breaking.
It becomes possible to manufacture spacers with a taper as small as an inch (approximately 0.9 mm).

As described above, according to the wave-shaped spacer for a folded air filter of the present invention, in an air filter of the type consisting of an accordion-shaped folded filter medium, both the upstream and downstream open ends of the filter medium are continuous. In addition to keeping the folded pleats separated by a spacer, the taper from the opening of the spacer to the closed end, which is more angular than before, has been made more uniform and flat, which improves the flow of air through the filter. It is evenly distributed in the filter media and reduces the pressure drop through the filter media (filter airflow resistance) while maintaining the same filter efficiency and the same amount of air flow through the filter compared to conventional filters.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of an air filter assembly using the spacer of the present invention, and FIG. 2 is an aluminum sheet or aluminum sheet in the process of being bent to form the tapered spacer of the filter assembly of FIG. A top view of the membrane strip, Figure 3 is the second
A partially enlarged view of a spacer formed as shown in the figure, with two opposing bent edges overlapping each other;
4 is a partially sectional side view showing a part of the filter assembly of FIG. 1; FIG. 4A is a partially enlarged view of FIG. 4;
FIG. 5 is a partially enlarged perspective view of the filter medium and spacer, and FIGS. 6 and 7 are 6-6 in FIG. 2, respectively.
8a, 8b and 8c are side views showing three different shapes of forming blades used in the rollers of FIGS. 6 and 7. 9 and 9 are partially enlarged sectional views showing each blade in detail. 10... Filter, 36... Spacer, 42, 62
...Roller, 46, 46', 46''...Folding line, 48,
50... Opposing edge, 52... Auxiliary folding line, 58, 60
...Folded portion of medium, 64, 66, 68...Blade.

Claims (1)

Claims: 1 (a) a rectangular aluminum sheet approximately 1 to 2 mils (approximately 25.4 to 50.8 micrometers) thick; (b) said sheet being folded in a zigzag pattern and continuously spaced at evenly spaced intervals; (c) a continuous V-shaped portion along each of the first and second edges on opposite sides of the sheet; The amplitude and period of the V-shaped portions are substantially constant first and second values, respectively, and (d) the number of the V-shaped portions within a constant width along the second edge is five times the number of the V-shaped portions within the same width along the first edge, and the amplitude and period of the V-shaped portions along the second edge are each substantially equal to the first value. and one-fifth of the second value, and (e) the fold line forming the V-shaped portion along the first edge extends entirely between the first and second edges, and , parallel to each other to the third and fourth edges of the sheet, (f) a folding line forming the V-shaped portion along the second edge;
In addition to the folding line common to the folding line extending across the first and second edges, a folding line of the sheet between the two edges extends from the second edge toward the first edge. said folding lines extending from about 80 to 90 percent of the width thereof and blending into the surface of said sheet, said folding lines extending between each other and entirely between said first and second edges; A corrugated spacer for a folded air filter that is substantially parallel to the folded line. 2 The first value of the amplitude at the second edge is approximately
2. A corrugated spacer for a folded air filter according to claim 1, wherein the spacer is 0.030 to 0.040 inches (approximately 0.7 to 1.0 millimeters). 3. A corrugated spacer for a folded air filter according to claim 1, wherein said sheet is 1145 aluminum having a hardness of substantially H19. 4. The angle of the bent portion along the second edge is about 80 to 85 of the angle of the bent portion along the first edge.
3. A corrugated spacer for a bent air filter according to claim 3, wherein the spacer is a wavy spacer. 5. A corrugated spacer for a folded air filter according to claim 4, wherein said amplitude along said second edge is about 20 to 25 times the thickness of said sheet.