US2565596A - Air cleaner - Google Patents

Description

S. L. COX

AIR CLEANER Aug. 28, 1951 2 Sheets-Sheet 1 Filed Dec, 20, 1949 R m m m f m S. L. COX

AIR CLEANER Aug. 28, 1951 2 Sheets-Sheet 2 Filed Dec, 20, 1949 INVENTOR.

B Shh/e5 1, Cal

Y WW Patented Aug. 28, 1951 UNITED STATES iPATNT ()FFICE AIR CLEANER Stanley L. Cox, Cincinnati, Ohio, assignor to The Kirk & Blum Manufacturing Company, Cincinnati, Ohio, a corporation of Ohio Application December 20, 1949, Serial No. 134,021

8 Claims.

The present invention relates to a dust collector and air cleaner and has for an object the provision of a device of this kind which is compact in structure, highly efficient in air cleaning and economical of power.

Another object is to provide a combination centrifugal dry and wet air cleaner wherein all of the heavier particles and nearly all of the finer particles including microscopic particles are removed by essentially dry centrifugal separation, while the entire volume of air treated, containing the small remainder of very fine particles only, is employed to set up a water spray of large volume for wetting the remaining entrained particles, to centrifugally remove the water and wetted particles and to discharge dust-free and water-free air.

Another object of the invention is to provide within a casing, resembling a cyclone type collector, a series of concentrically spaced and longitudinally related cylindrical Walls and cylinders for effecting the foregoing dust removing and air cleaning operations continuously and at minimum power cost.

Still another object of the invention is to provide a device of the class described with a lower contained body of water, or other liquid, as a common depository for all of the dust and solid matter that is removed from the air.

These and other objects are attained by the means described herein and disclosed in the accompanying drawings, in which:

Fig. 1 is a side elevational view of a device embodying the invention, parts being broken away to disclose the interior structure.

Fig. 2 is a top plan view of the device shown in Fig. 1.

Fig. 3 is a sectional view taken on line 33 of 1 and showing sectionally a sludge ejector associated with the liquid containing bottom of the device.

As shown in the drawings the device comprises a hollow casing indicated generally at I4 and cured at its top to the bottom of the cylindrical through the closed top 38 of said outlet pipe.

2 outer wall I5 and is provided with a bottom sludge outlet which may, if desired, be closed simply by a threaded cap 2| as illustrated in Fig. 1.

A cylindrical inner wall 22 is connected at its top in pressure tight relation to the bottom in.- terior face of the top I8 of the casing and it depends concentrically with wall I5 and terminates in a free bottom edge 23 a short distance above the juncture of wall I5 and bottom 20. Outer wall I5 has a rectangular opening therethrough which receives the rectangular extended end 24 of an air intake coupling or boot 25 for tangentially directing intake air to the inner face of outer wall I5. It will be seen that air to be cleaned is entered tangentially into the top of annular space 26 between the walls I5 and 22 so that air borne particles are subjected to centrifugal force and become concentrated on the inner face of outer wall I5 as the air travels centriiugally in its progressively descending path within the said space 26 until it reaches the bottom edge 23 of the inner cylindrical wall 22.

The bottom 22 is adapted to contain water or other suitable liquid 2?, and the top level of the body of water 27 normally assumes a position approximately as indicated by the dashed line L-L when the device is inoperative. A pair of cylinders 28 and 2d are arranged in the lower part of the cylindrical casing, the larger cylinder 28 lying concentrically intermediate the walls I5 and 22 while the smaller cylinder 29 is disposed concentrically of and inwardly of the inner cylindrical wall 22. These cylinders or rings 28 and 29 are substantially equally spaced from the opposite faces of cylindrical wall 22. The cylinder or ring 28 has its bottom edge 30 depending well below the water level L--L and is supported by any suitable means such as rods 3! which are welded or otherwise fixed to the inclined wall of bottom 23. The circular upper edge 32 is located above the normal water level L-L and may in most instances extend above the level of bottom edge 23 of inner cylindrical wall 22. Cylinder 29 is suspended with its bottom edge vell below the water level L-L and has its top edge at at some distance above the bottom edge 23 of inner cylindrical wall 22. The cylinder 29 is supported from the bottom interior thereof by a plurality of bars 35 which are welded or otherwise secured to the bottom end of a vertical ssupension rod 36. Spacing studs 31 serve to adjust and maintain a concentric relation between the cylinder 29 and wall 22. Rod 36 passes upwardly through outlet pipe I9 and An exteriorly mounted bridg 39 on the top 38 is centrally perforated to receive the threaded top end ill of the rod and nuts located above and below the bridge 38 provide for ready vertical adjustment of said rod and the cylinder 29 suspended. therefrom. A circular plate 42 is fixed on rod which passes through the center thereof, the diameter of plate ,2 being only slightly less than the inner diameter of fresh air outlet pipe with which it is axially centered.

Fixed to the inner circumferential. surface of cylindric 1 wall. is an annular baille ring 43 the nin m diameter 4 of which is at the lower ec and is approximately equal to the diameter of the fresh air outlet pipe I?) above it. Bafile 43?; is in practice made up of two beveled ri" connected together and forming an inverted right-angled groove overhanging the space between cylinder and the inner cylindrical wall 22.

A pair of intersecting sheets or strips 45 are fixed vertically edgewise to bottom 28 and they are submerged with their tops approximately level with the bottom edge 33 of cylinder 29.

Passing through bottom 25 is an internally threaded sleeve which allows an externally threaded pipe ll to be adjusted vertically therethrough. The pipe ll may have an unthreaded extension 33 at the top which is open and constitutes a vertically adjustable overflow for the water 2?.

Clean air outlet pipe H) has a. discharge openingin the side thereof extending from the top downwardly, and an eccentric scroll 49 extend ing therefrom. A rectangular outlet tube 53 embodies said scroll as one side thereof and a plate 5 tangential to the exterior of pipe is as the other side thereof. The space between is closed by top and bottom walls respectively and these are developed into a coupling or boot 52 to which the suction end of a power fan 53 is connected.

A pipe coupling E i is connected to top IS to receive a piped supply of tap water or other liqui" whereby liquid may be flowed down the inside face of wall 22. Another pipe coupling 55 is similarly mounted to provide a water flow over the inside face of wall 25. Either or both may be employed in filling the bottom or in re-establishing, or in maintaining the desired water level such as L-L or a level to be maintained by the adjusted overflow pipe 'll-48. The connections 5 3 and 55 may be used during operation the device under some conditions but are required for the actual cleaning of the air.

The device of the invention may be installed wholly inside the building or shop where the waste or dust is liberated by machines or other apparatus and the air discharged from the device may be found in many instances to be considerably cleaner than the outside atmosphere in the vicinity.

The installation of the device will be understood to include a conveyor conduit or system of conduits extending from one or more sources of dust and connected to coupling in known manner. Velocity air movement is established by operation of suitable suction fan such as 53 which has its intake port connected by a. A at to the coupling boot 52 which lea from the clean air outlet id. The discharge from the fan 53 be carried, if desired, to a suitable point for localized release into the atmosphere by means of a conduit or conduit system (not shown) In operation the fan 53 is actuated and withdraws air from the interior of pipe l9 and the center chamber 56 below it. The dust laden air to be cleaned is thus drawn from one or more sources (not shown) and enters as a velocity air stream through coupling or boot 25 from which it is charged tangentially into annular chamber 2d adjacent its top. The centrifugal force of the air stream separates all heavy particles and very nearly all of the fine dust particles, including part of the microscopic particles by stratifying the entrained dust and condensing the discrete dust particles against the inside face of wall l5. Those particles which may contact each other and form a larger and heavier unit mass may descend along wall l5 at a greater rate than the spiraling air stream in which they accumulated. When the entrained material is relatively diliicult to wet, a selected flow of water from connector 55 may be passed down over the inner of wall 5 5 to assist in the wetting and to aid in collecting the dust into heavier masses for earlier separation from the air stream thereby washing the dust away to further reduce dust loading at the water spray point hereinafter described.

When the downwardly spiraling stream has reached the top edge 32 of cylinder 28 approximately of the large dust particles still entrained will be located in the outer portion of the air stream and will descend between cylinder 2% and the wall I5 and be violently projected angularly onto the surface of the water between those members and are efiectively separated from the air stream.

The pressure of the air within annular chamber 26 is greater than that in the cylindrical chamber 56 due to the fact that the entire vol-- ume of carrier air mus still pass through the relatively restricted area between the top of the liquid body 2'! and the lower edge 23 of wall 22. As a result of this pressure the water level in the annular zone between the outer circumference of cylinder 29 and the wall i5 is depressed while the water level inside cylinder 29 is raised to establish a static pressure balance.

The entire volume of velocity air from annular channel 25 must now pass through the restricted annular zone between cylinder 28 and wall 22 with increased velocity and directly onto the depressed surface D or" the water. As a result a considerable volume of water is picked up by the air stream which now has entrained therein only about 5% of the originally contained dust.

The action of the spiraling air stream on the water imparts a violent and turbulent vortical action on the surface of the water impinged by the air stream. The fixed and submerged baffle s 45 confine the violent action eiiectively to a relatively shallow top layer of the water so that the force of the air stream is not wasted in setting the entire mass 27 into whirling motion. The water below sheets 45 is relatively tranquil so that the dust particles entering at the several places may settle quietly and form a denser sludge at the bottom of the water pool 21.

The direction of the air stream is now abruptly changed to an upward spiral flow due to the location of cylinder 25. There is thus set up a violent turbulence on the depressed surface D of the rater between cylinders 23 and 29 and, due to the restriction or the flow area, a large volume of the turbulent water is picked up in the air stream, and toe upstanding cylinder 29 and depending wall 22 form between them a narrow annular channel directing the flow upwardly against the inverted V-trough with great violence. A very dense water spray is thus formed and the greater part of the water with the now completely wetted particles is deflected into the center of cylinder 29 by the combined rebound of the water and the pressure flow of the air. The air and any entrained spray water continues a whirlin and upwardly travel toward air outlet l9 and centrifugal force separates entrained water and throws it against the inside surface of wall 22 where it collects and runs down over the upper bevel ring 43 and spills into the center of cylinder 29. The circular bafile plate 42 prevents short circuiting of the pressure air from the spray forming area to outlet pipe [9 so that water removal is assured. A water flow at 54 may be had to add to the water that is thrown onto wall 22 by the action of the air and this aids in washing the wetted microscopic particles down ultimately into pool 21.

The scroll 49 adjacent the top outlet 50 assists materially in maintaining an extremely active whirling motion in the air within pipe l9 and the chamber 56 and thus augments the centrifugal separation force which carries through from annular chamber 26.

The air finally reaching fan 53 is free of dust or waste particles and of water droplets. A slight increase in humidity of the discharge air over that of the intake can be detected by instrument but is not otherwise apparent. Under many industrial environments the discharge air is cleaner and more healthful than the surrounding outside atmosphere and is therefor desirably distributed interiorly of the building. The device is conveniently contained within the building under practically all operating conditions when water or other safe liquid is used as the medium in which the dust is collected in the form of sludge.

The nature of the materials may produce a collected sludge that is essentially a waste product and as such is more easily handled as sludge in either condensed or diluted form. In some instances the collected dust particles removed from the intake air stream may contain valuable materials that warrant further cleaning and separation. The dust of precious metals is one example of a sludge ingredient that justifies separation and recovery by further treatment. Wood dust, cellulose fiber particles and kindred materials collected in quantity may warrant processing for lay-products or may be drained and ultimately burned or otherwise disposed of without troublesome scattering.

For installations wherein large quantities of dust materials are collected it should be understood that the automatic removal of sludge should be provided for in a manner that may be carried on continuously or intermittently during operation of the air cleaner. Any approved mechanism ma be used for this purpose for example as indicated somewhat schematically in Fig. 3. Such a sludge ejector consists essentially of a conveyor housing H open at its top above the water level LL in the device and communicating with the bottom interior of the member 20 through a chamber C which surrounds the clean out opening from which cap 2| of Fig. l is omitted. A power driven elevating conveyor E of any suitable type for example an Archimedean screw, or an endless belt with blades or buckets (not detailed) may be employed to carry away the settlings and heavier collected material from the bottom of pool 21. The liquid flow through connections 54 ill 6 and/or 55 may be adjusted to maintain the liquid level of the pool 21.

The overflow pipe 4l48 may be connected to a drain and may carry away fine particles that persist in floating on the surface.

From the foregoing it will be appreciated that the air cleaner of the invention operates as a combination cleaner in that the separation of approximately of the entrained material in the intake air is effected by fundamentally a dry centrifugal separation process in the annular chamber 26, regardless of whether or not a liquid fiow over wall 15 is used, and that the remaining approximately 5% of the total entrained dust (which is of finer and largely microscopic particle size) is dispersed widely in the entire original volume of entrained air which picks up a large volume of water and converts it into an extremely effective water spray beneath the annular inverted V-baflle formed by the ring 43. The dust loading in the wet spray operation is thus greatly reduced and the efficiency of the cleaning operation is correspondingly more eiiective. The increased effectiveness in practice results in reduced operational power costs as compared with wet collectors in which the intake air stream with all of its entrained dust is charged into a body of liquid. Moreover the said type of wet collectors have presented some difliculties in that they may not have the velocity stream appreciably varied to suit changing work load conditions without danger of allowing either some dust or some water to pass through with the discharge air. In contrast the device of the present invention may have its work load varied widely without requiring adjustment and without impairment of its air cleaning function. In no instance does the discharge outlet air stream contain any entrained water droplets.

What is claimed is:

1. An air cleaner comprising a centrifugal separator of the cyclone type including an outer cylindrical wall, a top, a vertical outlet air pipe extending concentrically therethrough for a distance above and below said top, a bottom forming a liquid tight closure for said casing serving to establish an open topped basin within the bottom of the casing, means to admit liquid into the casing whereby a liquid pool is established in said basin to a selected liquid level confined at its top within the lower end of the cylindrical outer wall, a pair of cylinders in the lower part of the casing concentrically spaced from the inner circumference of said outer wall and from each other, said cylinders having their lower edges and upper edges respectively disposed below and above the said liquid level in said pool basin, a cylindrical inner casing wall extending concentrically downwardly from the casing top and terminating intermediate the cylinders and below the top edge of the inner cylinder, an annular bafile secured on the inner circumference of said inner cylindrical wall and having a groove in the bottom thereof overhanging the top edge of the inner cylinder, means for introducing a dust laden velocity air stream tangentially into the annular space between the inner and outer cylindrical walls adjacent the top of the casing and means for exhausting air tangentially from the outlet pipe above the top of the casing.

2. In combination a cylindrical outer casing, a collector basin forming a water tight closure at the bottom of said casing, a top closing the upper end of said casing, an air outlet pipe extending through the top for a distance above and below the top, a closure for the top of said outlet pipe, means including a scroll casing adapted for connection with a, suction fan for exhausting air tangentially from the outlet pipe adjacent the top thereof, an inner cylindrical wall located concentrically intermediate the outlet pipe and the outer casing wall and extending from the casing top to a level slightly above the top of the collector basin, a pair or vertical cylinders spaced respectively concentrically within and without the circumference of the inner casing wall and having the bottom edges thereof terminating below the top of the pool basin, the top edge of the inner cylinder extending above the bottom of said inner cylindrical wall, an inverted V-shaped baffle secured to the inner circumference of said inner cylindrical wall in overhanging relation closely above the top of the inner cylinder and a circular baflle plate fixedly mounted above said inverted V-shaped baflie and having its circumference spaced concentrically from said inner cylindrical wall below the bottom of the outlet pipe.

3. In a device of the class described the combination of an outer cylindrical wall, a top, an inner cylindrical wall depending from the said top concentrically in spaced relationship to the outer cylindrical wall, means for tangentially introducing air to be cleaned into the top portion of the annular space between the inner outer cylindrical walls, an outlet pipe passing concentrically through the top and extending above and below said top, means including a scroll casing connected to the outlet pipe above the top and communicating with the interior of the outlet pipe and adapted for connection with an air exhauster, a liquid tight collector basin forming a bottom for the outer casing, means to supply liquid selectively to the top inner circumferences of said inner and outer casing walls, a vertically adistable overflow pipe extending up wardly through the collector basin and terminating above the top thereof, an outer cylinder disposed intermediate the outer and inner cylindrical walls adjacent the bottom thereof, inner cylinder disposed concentrically in spaced relation to the inner cylindrical wall, an annular water bafiie secured interiorly of the inner cylindrical wall in overhanging relation to the space between the said inner cylindrical wall and said inner cylinder and an air baffle disc supported horizontally intermediate said water baiile and the bottom of the outlet pipe.

4. A combined dry and wet separation air cleaner comprising a cylindrical upright casing, a bottom on the casing, a liquid pool contained by said bottom and providing a deformable liquid floor entirely across the lower end of the casing, a closed top on said casing, an outlet pipe extending through the center of said top for a distance above and below the latter, means adapted to exhaust air tangentially from the outlet pipe, means to tangentially introduce air to be cleaned into the upper circumferential portion of the casing, a cylindrical skirt depending from the top will into the liquid pool whereby the interior of the casing is divided into an annular chamber and a cylindrical chamber surrounded thereby, a pair of upright annular bafiies disposed respectively in the bottom portions of the annular and cylindrical chambers and spaced concentrically from relatively opposite faces of said skirt and depending for a distance below the surface of the pool and below the bottom edge of the skirt, wholly submerged baiiles traversing the pool below the said annular bafiies, an annular bafile member secured to the inner circumference of the skirt in closely overhanging relation to the top edge of the upright baffle in the cylindrical chamber and presenting an inverted V-groove above the said top edge, and an over flow pipe extending upwardly through the pool from the bottom exterior of the easing into the bottom center area of the cylindrical chamber surrounded by the upright baiile in the latter.

5. In an air cleaning dust collector, an inner and an outer centrifugal collector disposed concentrically one within the other and divided by a common depending cylindrical wall, a basin forming a closure across the bottom of the outer collector and disposed below the lower fr e edge of said depending wall, a body of liquid in the basin defining between its top and the bottom edge of the aepending wall a vertically limited communication between the lower ends of said collectors, an. inner cylinder havug its lower edge submerged for a distance in said liquid and extending concentrically in inwardly spaced relation for a distance above the bottom depending edge of said common wall, an annular inverted V-trough carried by the inner surface of said common wall in slightly spaced relation to the top of the cylinder and overhanging the latter. a second cylinder submerged in said liquid at its bottom and concent ically spaced outwardly of the common wall, transverse baiiles extending across the basin and wholly submerged below the bottom of the inner cylinde', means to introduce air to be cleaned tangentially into the upper portion of the outer collector, and means to exhaust air tangentially from the upper portion of the inner collector.

6. In an air cleaner apparatus of the class described the combination of a pair of centrifugal separators disposed one within the other and separated by a common wall, a scroll casing connected with the air outlet of the inner separator and connectible with air exhausting means for extracting air tangentially from said inner separator, means to admit air to be cleaned tangentially into the upper portion of the outer separator, a liquid pool in the apparatus with the top surface of said pool forming a common floor for both of said separators, endless bafiles disposed in concentric relation at opposite sides of said common wall and extending for a distance above and below the surface of the liquid p001, submerged bafiies in the liquid pool below and transversely of the said endless bafiles, and an inverted V-grooved baffie connected to the inner face of the common wall and in closely over hanging relation to the top edge of the endless bafile in the inner separator.

'7. In an air cleaner apparatus of the class described the combination of a pair of centrifugal separators disposed one within the other and separated by a common wall, a scroll casing connected with the air outlet of the inner separator and connectible with air exhausting means for extracting air tangentially from said inner separator, means to admit air to be cleaned tangentially into the upper portion of the outer separator, a liquid pool in the apparatus with the top surface of said pool forming a common floor for both of said separators, endless bafiles disposed in concentric relation at opposite sides of said common wall and extending for a distance above and below the surface of the liquid pool, means to provide a selective liquid flow over the major inner surface of the separators,

submerged baflles in the liquid pool below and transversely of the said endless bafiles, and an inverted V-grooved baflle connected to the inner face of the common wall and in closely overhanging relation to the top edge of the endless baflle in the inner separator.

8. In an air cleaner apparatus of the class described the combination of a pair of centrifugal separators disposed one within the other and separated by a common wall, a scroll casing connected with the air outlet of the inner separator and connectible with air exhausting means for extracting air tangentially from said inner separator, means to admit air to be cleaned tangentially into the upper portion of the outer separator, a liquid pool in the apparatus with the top surface of said pool forming a common floor for both of said separators, endless bafiles disposed in concentric relation at opposite sides of said common wall and extending for a distance above and below the surface of the liquid pool, means to selectively provide a liquid flow downwardly over the major inner surface of the separators, a vertically adjustable overflow pipe ex- STANLEY L. COX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,461,174 Bennett July 10, 1923 1,841,556 Stelz Jan. 19, 1932 FOREIGN PATENTS Number Cormtry Date 451,274 Germany Oct. 24, 1927 155,435 Switzerland Sept. 1, 1932

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