US3662557A

US3662557A - Aspirator disposal system for air conditioner evaporator condensate

Info

Publication number: US3662557A
Application number: US77931A
Authority: US
Inventors: David E Morgan
Original assignee: Dunham Bush Inc
Current assignee: Dunham Bush Inc
Priority date: 1970-10-05
Filing date: 1970-10-05
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16

Abstract

The scroll housing for a centrifugal blower is provided with a narrow elongated slot completely across the width of the housing and along the bottom of the same upstream of the scroll outlet which intersects the condensate drain pan. A plurality of laterally spaced, liquid smashing fingers extend upwardly at approximately 45* to the direction of flow, downstream of the aspirator slot, with the fingers struck out from the scroll bottom to define secondary aspirator slots downstream of the fingers. The bottom edge of the scroll housing, at its outlet is also upwardly inclined in the direction of flow to direct the condensing air carrying the atomized condensate against the full surface of the condenser coil positioned in the path thereof, for evaporation by thermal exchange. A rectangular opening leads from the condenser chamber downstream of the scroll housing and an adjustable door covered opening associated with the room sidewall of the unit and aligned therewith allows fresh makeup air to join the recirculated room air passing through the filter and the evaporator coil and separated from the condensing air by an appropriate bulkhead.

Description

United States Patent 1 51 3,662,557 Morgan May 16, 1972 [s41 ASPIRATOR DISPOSAL SYSTEM FOR Primary Examiner-William 1. Wye

AIR CONDITIONER EVAPORATOR CONDENSATE [72] Inventor: David E. Morgan, Harrisonburg, Va. [73] Assignee: Dunham-Bush, Inc., Harrisonburg, Va.

[22] Filed: Oct. 5, 1970 [21 Appl. No.: 77,931

[52] US. Cl ..62/279, 261/78, 62/428 [51 Int. Cl ..F25b 47/00 [58] Field 01 Search ..62/279, 280, 428; 261/78 [56] References Cited UNITED STATES PATENTS 2,4I 7,743 3/1947 Eberhart ..261/78 2,7 [0,5 10 6/1955 Roseman ..62/280 3 ,022,647 2/ I 962 Mullen ..62/262 3 945.449 7/1962 Surdle ..62/279 3,442,092 5/1969 Pratt ..62/279 Attorney-Sughrue, Rothwell. Mion, Zinn & Macpeak ABSTRACT The scroll housing for a centrifugal blower is provided with a narrow elongated slot completely across the width of the housing and along the bottom of the same upstream of the scroll outlet which intersects the condensate drain pan. A plurality of laterally spaced, liquid smashing fingers extend upwardly at approximately 45 to the direction of flow, downstream of the aspirator slot. with the fingers struck out from the scroll bottom to define secondary aspirator slots downstream of the tingers. The bottom edge of the scroll housing, at its outlet is also upwardly inclined in the direction of flow to direct the condensing air carrying the atomized condensate against the full surface of the condenser coil positioned in the path thereof, for evaporation by thennal exchange. A rectangular opening leads from the condenser chamber downstream of the scroll housing and an adjustable door covered opening associated with the room sidewall of the unit and aligned therewith allows fresh makeup air to join the recirculated room air pasing through the filter and the evaporator coil and separated from the condensing air by an appropriate bulkhead.

1] Claims, 5 Drawing figures MTENTEMY I5 1972 n G? h SHEET 2 OF 2 FIG. 5

BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates to air conditioners and dehumidifiers and the like and more particularly to such apparatus which include aspirating means for introducing water into the condensing air for subsequent evaporation on the condenser coil to dispose of the same.

DESCRIPTION OF THE PRIOR ART During the cooling of room air by an air-conditioning unit, the reduction in temperature of the air below its dew point results in the condensation of moisture from the air being processed, which condensate must be removed from the apparatus producing the same. With the condenser normally separated by a partition or bulkhead means from the evaporator of the air-conditioning unit or cabinet, allowing the condensate to contact the surfaces of the condenser coil results in evaporation of the same and discharge of the hot moist air outside of the room being conditioned. In the past, it has been conventional to position the evaporator coil at a vertically higher position than the condenser coil so that the condensate collected by a drain pan or the like beneath the evaporator coil is gravity fed to the vicinity of the condenser coil where it enters the condensing air stream for ultimate contact with the condenser coil for evaporation and discharge from the unit. Necessarily, this involves a cabinet configuration of increased height due to the necessity of the vertical stacking of the condenser and evaporator coils.

Due to the desirability of keeping the air-conditioning cabinet as compact as possible, it is particularly important to locate both the evaporator and condenser coils in laterally spaced, vertical alignment. This, of course, eliminates the possibility of gravity feed of the liquid condensate to the condenser region. Mechanical devices in the form of slinger means, fixed to the outer periphery of a propeller type condensing air fan have been employed to some extent, to pick up the condensed water within the drain pan on the bottom of the air-conditioning unit or cabinet and sling the same against the surfaces of the condenser coil for evaporation. Where a scroll enclosed centrifugal fan is employed to produce this air stream, it is impossible to use a rotating slinger arrangement.

Attempts have also been made to employ aspirating principles in conjunction with these types of centrifugal blowers for sucking up the accumulated condensate within the drain pan and causing atomization to the liquid during its movement in the condensing air to the condenser coil. One arrangement for accomplishing the same is set forth in U. S. Pat. No. 3,442,092, patented May 6, I969, to John N. Pratt and assigned to the common assignee. The air conditioning apparatus of the patent employs a scroll type blower or centrifugal fan which directs a high velocity air stream through the condenser coils of the air conditioner with a plurality of aspirator tubes communicating with the drain pan collecting the evaporator condensate. The aspirator tubes draw the condensate and spray into the air stream for evaporation and discharge from the apparatus as water vapor.

The provision of the aspirator tubes while satisfactory, to effeet the introduction of the condensate liquid into the air stream and atomization of the same, due to the limited size of the aspirator tubes and the limited area of projection of the atomized liquid exiting from the same, results in the utilization of only a portion of the condenser coil surfaces as the means for evaporating the condensate. Further, due to the limited size of the aspirator tubes they become clogged with debris and dirt particles and the like, greatly reducing their effectiveness, or under severe conditions, actually cutting off aspiration. Further, in the referred to patent, the fresh makeup air is removed from the inlet side of the fan, thus reducing the effectiveness of the same.

SUMMARY OF THE INVENTION The present invention is directed to an improved aspirating system for the disposing of the evaporator condensate by insuring maximum continuous aspiration of the liquid condensate by the condenser fan, the removal of accumulated dirt particles and the like within the condensate liquid, increased atomization of the aspirated liquid, and the spraying of the atomized liquid against the full surface of the condenser coil with the efficiency of the aspiration increasing with the increased condensate loads.

The system is employable in a refrigeration air conditioner which includes, within the cabinet, an air-cooled condenser and an evaporator separated by partition means and the centrifugal blower rotating within a scroll housing for producing a condensing air stream discharging through the condenser. The drain pan within the bottom of the cabinet carries the condensate from the evaporator to the blower and through the partition means. The improvement lies in the aspirator means, which comprises a narrow elongated slot extending across the bottom of the scroll housing adjacent to the outlet end and intersecting the drain pan. Further, the plurality of laterally spaced liquid smashing fingers extend ,upwardly from the bottom of the scroll housing, downstream of the aspirator slot to fully atomize the aspirated liquid. Preferably, the fingers are struck from the bottom of the pan and bent upwardly at approximately 45 in the direction of air flow, with the openings in the scroll housing formed by the struck out fingers defining secondary aspirating means downstream of the fingers.

The scroll housing itself terminates at its outlet end in a nar row inclined bottom edge which assists in both atomizing the aspirated liquid and directing the same upwardly toward the surfaces of the condenser coil for subsequent evaporation. The edge is perforated to eliminate the built-up of back pressure in the condensing air stream and to provide a third aspiration of water. The vertical sidewalls of the scroll housing are such that central openings within the sidewalls act as the blower inlets for the condensing air and a rectangular opening facilitates bleeding of fresh air therefrom, downstream of the blower. The fresh air passes through an aligned rectangular opening in a front panel, controlled by an adjustably pivotable door which overlies the same, thus delivering pressurized fresh make-up air to the recirculated room air upstream of the filter and evaporator coil.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of an air conditioning unit incorporating the improved aspirator condensate disposal arrangement of the present invention.

FIG. 2 is a fragmentary side view of the unit shown in FIG. 1.

FIG. 3 is a top plan view of the unit shown in FIG. 1.

FIG. 4 is a sectional, elevational view of a portion of the unit shown in FIG. 3 taken about line 44.

FIG. 5 is an end elevational view of a portion of the unit shown in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the air-conditioning unit 10 of the present invention constituting in general, a rectangular cabinet, which may, in fact, form only a portion of the combined heating and cooling unit incorporated in a common assembly. In this case, the heating means for the assembly is not illustrated. Further, the unit 10, as illustrated, constitutes an interior cabinet construction with some of the walls thereof forming walls of the complete finished assembled unit while other walls associated therewith to define air passages not illustrated but necessary to the function of the combined heating and cooling unit as a whole.

In order to fully describe the present invention, the air conditioning unit 10 incorporates a sealed drain pan 12 which, in fact, forms the bottom of the assembly, a plurality of vertically extending frame members 14 act in conjunction with the horizontal frame members such as top 16 to support the components within the unit and define, in conjunction with a configured bulkhead 18 and transverse partition 20, separate evaporator and condenser regions indicated at 22 and 24, respectively. In this regard, a vertically extending evaporator coil 26 is positioned within the drain pan l2 and overlying the front of the same is a removable filter 28, the room air entering through the filter 28 passing over the evaporator coil and rising vertically from the evaporator area 22 for return to the room after being conditioned. The evaporator coil 26 is suitably supported by the longitudinally spaced vertical frame members 14, as shown. At the rear of the unit, and in vertical alignment, is the condenser coil 30, also supported by the vertical frame members 14. The condenser coil 30 and evaporator coil 26 are coupled in a conventional refrigeration system with the refrigerant passing through the same as result of operation of compressor unit 32 within the right hand portion of the unit 10. The forced air moving through the evaporator coil 26 is created by an evaporator fan (not shown), while the air passing through the condenser coil 30 is discharged from the outlet 34 of the condenser fan 36. Condenser fan 36 constitutes a centrifugal blower, including blower wheel 38 mounted for rotation within a scroll housing 40 which is cylindrical in cross section, except for the rectangular discharge end defined by a top wall 42, left and right hand sidewalls 44 and 46, respectively, and a scroll housing bottom wall 48. The scroll housing therefore acts in conjunction with bulkhead 18 including vertical wall portion 50 and inclined wall portion 52 to define the condenser region 24 along with condenser coil 30.

The condenser cooling air enters from the outside, through a birdscreen 54, into a chamber 56 defined by a front wall 58, sidewall 60, the scroll housing 40, transverse partition 20 and a top cover (not shown), FIG. I. Positioned within the chamber 56, is compressor unit 32. The condensing cooling air enters scroll inlets constituting circular openings 62 and 63 within sidewalls 44 and 46 of the scroll housing and is discharged from the condenser fan through outlet opening 34 into the condenser chamber 24. In this respect, the blower wheel 38 is mounted for rotation on the end of shafi 64 extending from the fan motor 66 which is mounted within the right hand sidewall 46 of the scroll housing by means (not shown). As mentioned previously, additional walls or panels (not shown) overlie portions of unit 10, such as the left hand side, to complete, along with a top cover, the various air passages for the unit.

The present invention is directed to the improved aspirating and double atomizing means for the condensate for ensuring maximum evaporation and impingement of atomized condensate on the full surfaces of the condenser coil for maximum evaporation of the same. In this respect, the scroll is provided with an elongated slot 68 defined by the termination of the cylindrical portion 70 of the scroll housing 40 and the flat bottom portion 48 at discharge end of the scroll. Slot 68 extends completely from one sidewall 44 to the other 46. The slot is preferably from one-quarter of an inch to one-half inch in height. The blower wheel 38, in rotating about its axis in a clockwise direction, FIG. 4, causes a high velocity air stream to move over and across the slot 68 defined by the end of the cylindrical wall 70 of the scroll housing and the bottom wall 48. When the liquid condensate, as indicated, reaches the area of the slot opening 68, the suction efi'ect of the moving air stream indicated by the arrows, FIG. 4, causes aspiration of the same with the liquid immediately impinging a pair of fingers 72, of rectangular configuration, struck out of housing bottom wall 48, which act as water smashers to smash or break up and atomize the liquid into particles 74 which then exit from the outlet opening 34 of the condenser fan. The fingers 72 are inclined upwardly in the direction of air stream flow, at about 45, to aid not only in the atomization of liquid, but also, in causing the atomized particles 74 to be deflected against the full surface of the rectangular condenser coil 30. Further, by

striking the fingers 72 out of the bottom 48 of the scroll housing, secondary aspirator slots 76 are formed thereby, allowing additional liquid to be aspirated into the moving air stream, which liquid impinges against the turned up, inclined edge 78 of the scroll housing bottom wall which also tends to break up and atomize the aspirated liquid. Secondary aspirator carries light condensate loads. This valuable feature in combination with finger smashing greatly increases disposal capacity for high condensate loads. Preferably, laterally spaced openings or apertures 80 are formed within the bent up edge 78 of the scroll housing at its outlet end 34 to prevent the build-up of back pressure due to the presence of the edge 78 in the air stream and provides for additional aspiration. This, therefore, allows full atomization of the aspirated liquid without reducing the efficiency of the condenser fan in creating the necessary condensing air stream. ln similar manner to fingers 72, the edge 78 of the scroll housing is inclined upwardly in the direction of air flow at approximately 45. The flow of the condensing air carrying the atomized condensate may be readily seen by the arrows depicting this flow in both FIGS. 3 and 4.

Another aspect of the present invention resides in the means for removing a portion of the condensing air stream on the downstream side of the centrifugal blower, as fresh makeup air for the recirculated room air which is introduced into the room air prior to passage through the evaporator coil. This is best seen in FIGS. 1, 2 and 3. Just downstream of the blower discharge opening 34, there is provided an opening 82 into the condenser region which allows a portion of the pressurized fresh air to be bled off as indicated by the arrows. The fresh air enters between the vertical frame 14 supporting the evaporator coil 26, the partition 87, and the top wall 16. The air next exits through a pivotable fresh air door 84 of rectangular configuration which overlies a similarly shaped opening 86 within front wall 58. Right angle flanges 88 support the door 84 via a pivot shah 90 allowing the door to swing outwardly to a variable extent to control the delivery of the fresh air to the inlet side of the evaporator coil 26 as indicated by the arrows, FIG. 1. In in order to control the position of the same suitable control means are provided including a rotatable disc 92 mounted on the front wall 58 via pivot support 94. A plurality of perforations 96 allows a link 98 to be adjustably positioned with respect to the same, while the opposite end of the link is pivotably connected to the door flange 100 at a fixed position. These means are only illustrative of one manner in which the door 84 may be adjustably positioned with respect to the opening 86. It is noted that the fresh air first passes through filter 28 after mixing with the recirculated air, prior to passing through the evaporator coil 26 for conditioning.

The operation of the condensate removal system as described above and the arrangement for directing pressurized fresh make-up air into the recirculated room air stream prior to entering the filter evaporator is believed to be readily apparent from the above description. Briefly, however, during operation, the moisture which drops from the evaporator coil passes by gravity through inclined slots, or by slight inclination of the sealed drain pan l2, beneath bulkhead l8 and from the evaporator region 22 to a position where it underlies the condenser fan scroll housing 40. The drain pan may in fact be provided with a well (not shown) within the portion underlying the condenser fan so as to effect accumulation of the liquid in the area of the aspirating slot 68. When the condensate level within the drain pan reaches the level of the aspirating slot 68, illustrated by the dotted line, FIG. 4, the high velocity air stream exiting from blower wheel 38 draws the water by aspiration which impinges the finger 72 under high velocity smashing the liquid into fine droplets with the atomized particles forced by the air stream moving upwardly and across the inclined finger 72, into full contact with the complete rear surface of the condenser coil 30. At low loads, the secondary aspirator slots 76 downstream of the finger perform most of the aspiration and the inclined edge 78 of the bottom wall 48 of the scroll housing provides most of the atomization. At high loads, the two fingers 72 and the large full width aspirator slot 68 act to deliver most of the aspirated and atomized condensate to the face of the condenser. Any liquid not being evaporated by the condenser coil 30 or moving outwardly with the condensing air stream, drains to the bottom of the unit and returns again to the aspirating region. In the present invention, the ability of the aspirating means to dispose of liquid condensate substantially increases with the increase in condensate to be disposed, For instance, if during a rain storm or flood condition there is ten times the normal supply of water in the drain pan, the large capacity blower and the primary and secondary aspirators become capable of removing not only times the volume of water per unit time, but up to 20 times that initially available to the aspirator by splashing it against the face of the condenser. Any water not vaporizing or moving via the air stream through the condenser coil runs down the inside face of the condenser and is readily recirculated back to the aspirator slot by movement along the drain pan much in the same manner as the original condensate from the evaporator. Further, any atomized condensate added to the fresh air diverted through door 84, through opening 86 and past the fresh air door recondenses on the evaporator coil 26. The percentage of fresh air being added to the recirculating air normally constitutes a ratio of one to 10.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a refrigeration air conditioner including:

a cabinet,

an air cooled condenser,

an evaporator positioned within said cabinet and separated from said condenser by partition means,

a centrifugal, cylindrical blower wheel mounted for rotation about a horizontal axis within said cabinet,

a scroll housing,

a drain pan extending along the bottom of the cabinet and having portions underlying the condenser, the evaporator and the blower scroll housing, said blower scroll housing including a semi-cylindrical portion concentrically surrounding and spaced from said wheel and a flat bottom wall portion extending away from said semi-cylindrical portion and parallel to said drain pan,

first aspirator means comprising a narrow, elongated slot extending fully across said scroll housing at the juncture between the semi-cylindrical portion and the fiat bottom wall portion of said scroll housing,

second aspirator means comprising a plurality of laterally spaced liquid smashing fingers extending upwardly from the bottom of the scroll housing and struck out of the same, downstream of said first aspirator means for atomizing condensate carried by the blower air stream aspirated by said first aspirator means.

2. The air conditioner as claimed in claim 1, wherein said spaced fingers are inclined upwardly at an angle approximately 45 to the direction ofthe air flow.

3. The air conditioner as claimed in claim I, wherein said fingers are struck out of the bottom of said scroll housing with the openings resulting therefrom defining secondary aspirator means for said condensate, downstream of said fingers.

4. The air conditioner as claimed in claim 2, wherein said fingers are struck out of the bottom of said scroll housing with the openings resulting therefrom defining secondary aspirator means for said condensate downstream of said fingers.

5. The air conditioner as claimed in claim 3, wherein the bottom of said scroll housing terminates at its outlet end in a narrow outwardly inclined edge which assists in atomizing said liquid condensate carried by said air stream with said edge being apertured to eliminate build up of back pressure within the scroll housing and defining third aspirating means to aspirate water into the air stream discharging from the scroll housin 6. T e air conditioner as claimed in claim 4, wherein the bottom edge of said scroll housing is inclined upwardly and outwardly to assist in atomizing the condensate carried by the air stream with said edge being apertured to eliminate build up of back pressure within the scroll housing and defining third aspirating means to aspirate water into the air stream discharging from the scroll housing.

7. The air conditioner as claimed in claim I, wherein said scroll housing includes spaced, vertical sidewalls, an opening formed within one of said vertical sidewalls downstream of said blower, a front panel and transverse partition means carried by said cabinet to separate said blower scroll housing from the evaporator, a rectangular opening formed within said front panel corresponding to the rectangular opening within the scroll housing sidewall, an adjustably pivotable door overlying said front panel opening to vary the volume of fresh make up air delivered thereby to the air stream prior to circulation through the evaporator coil from the room being conditioned.

8. The air conditioner as claimed in claim 5, wherein said scroll housing includes spaced, vertical sidewalls, an opening formed within one of said vertical sidewalls downstream of said blower, a front panel and transverse partition means carried by said cabinet to separate said blower scroll housing from the evaporator, a rectangular opening formed within said front panel corresponding to the rectangular opening within the scroll housing sidewall, an adjustably pivotable door overlying said front panel opening to vary the volume of fresh make up air delivered thereby to the air stream prior to circulation through the evaporator coil from the room being conditioned.

9. In a blower assembly comprising a centrifugal blower wheel rotating within a scroll housing for producing an air stream, a water reservoir underlying said scroll housing, and aspirator means for aspirating water from said reservoir into said air stream, the improvement wherein said aspirator means comprises:

a narrow elongated slot extending across said scroll housing adjacent the bottom thereof and upstream of the centrifugal blower outlet and just above said water reservoir,

a plurality of liquid smashing fingers extending upwardly from the bottom of said scroll housing downstream of said aspirator slot.

10. The blower assembly as claimed in claim 9, wherein said fingers are struck out of the bottom of said scroll housing with the openings resulting therefrom defining secondary aspirator means for the water within said reservoir, downstream of said fingers.

11. The blower assembly as claimed in claim 10, wherein the bottom of the scroll housing terminates at its outlet end, and a narrow upwardly inclined edge which assists in atomizing the water, with the edge being apertured to eliminate build-up of back pressure within the scroll housing and to fon'n tertiary aspirating means for aspirating water into the bottom of the scroll housing.

Claims

1. In a refrigeration air conditioner including: a cabinet, an air cooled condenser, an evaporator positioned within said cabinet and separated from said condenser by partition means, a centrifugal, cylindrical blower wheel mounted for rotation about a horizontal axis within said cabinet, a scroll housing, a drain pan extending along the bottom of the cabinet and having portions underlying the condenser, the evaporator and the blower scroll housing, said blower scroll housing including a semi-cylindrical portion concentrically surrounding and spaced from said wheel and a flat bottom wall portion extending away from said semi-cylindrical portion and parallel to said drain pan, first aspirator means comprising a narrow, elongated slot extending fully across said scroll housing at the juncture between the semi-cylindrical portion and the flat bottom wall portion of said scroll housing, second aspirator means comprising a plurality of laterally spaced liquid smashing fingers extending upwardly from the bottom of the scroll housing and struck out of the same, downstream of said first aspirator means for atomizing condensate carried by the blower air stream aspirated by said first aspirator means.

2. The air conditioner as claimed in claim 1, wherein said spaced fingers are inclined upwardly at an angle approximately 45* to the direction of the air flow.

3. The air conditioner as claimed in claim 1, wherein said fingers are struck out of the bottom of said scroll housing with the openings resulting therefrom defining secondary aspirator means for said condensate, downstream of said fingers.

5. The air conditioner as claimed in claim 3, wherein the bottom of said scroll housing terminates at its outlet end in a narrow outwardly inclined edge which assists in atomizing said liquid condensate carried by said air stream with said edge being apertured to eliminate build up of back pressure within the scroll housing and defining third aspirating means to aspirate water into the air stream discharging from the scroll housing.

6. The air conditioner as claimed in claim 4, wherein the bottom edge of said scroll housing is inclined upwardly and outwardly to assist in atomizing the condensate carried by the air stream with said edge being apertured to eliminate build up of back pressure within the scroll housing and defining third aspirating means to aspirate water into the air stream discharging from the scroll housing.

7. The air conditioner as claimed in claim 1, wherein said scroll housing includes spaced, vertical sidewalls, an opening formed within one of said vertical sidewalls downstream of said blower, a front panel and transverse partition means carried by said cabinet to separate said blower scroll housing from the evaporator, a rectangular opening formed within said front panel corresponding to the rectangular opening within the scroll housing sidewall, an adjustably pivotable door overlying said front panel opening to vary the volume of fresh make up air delivered thereby to the air stream prior to circulation through the evaporator coil from the room being conditioned.

9. In a blower assembly comprising a centrifugal blower wheel rotating within a scroll housing for producing an air stream, a water reservoir underlying said scroll housing, and aspirator means for aspirating water from said reservoir into said air stream, the improvement wherein said aspirator means comprises: a narrow elongated slot extending across said scroll housing adjacent the bottom thereof and upstream of the centrifugal blower outlet and just above said water reservoir, a plurality of liquid smashing fingers extending upwardly from the bottom of said scroll housing downstream of said aspirator slot.

11. The blower assembly as claimed in claim 10, wherein the bottom of the scroll housing terminates at its outlet end, and a narrow upwardly inclined edge which assists in atomizing the water, with the edge being apertured to eliminate build-up of back pressure within the scroll housing and to form tertiary aspirating means for aspirating water into the bottom of the scroll housing.