Smudge Eliminating Variable Volume Selective Pattern Control Air Diffuser

Abstract

An adjustable flow air diffuser for selectively controlling air flow from an air distribution system minimizing induction of dirty air into the discharged air stream to prevent smudging of the surfaces of the discharge outlet and permitting selection of desired air distribution patterns. By employing a selectively adjustable damper plate which is perforated, the damper serves to effect desired deflection of the primary air stream along paths transverse to the axis of flow through the diffuser, while some of the primary air passing axially through the damper acts to prevent dirt accumulations on the surrounding surfaces. Forming the damper plate with a slot at the point of securement to the support shaft serves to permit selective lateral shifting of the damper with respect to the supply duct axis to selectively vary air distribution patterns.

Description

BACKGROUND OF INVENTION

This invention relates to the art of air diffusers, and more particularly to air diffusers providing selective control of volume flow rate and air distribution patterns of air distributed to a given area, while at the same time minimizing smudging of the surface areas adjacent the outlets of the air diffuser.

Air diffusers have long been employed in the air conditioning industry to provide selective control of air volume flow rates and air distribution paths from the conditioned air supply system ducts to the conditioned area.

Such prior art air diffusers have generally employed a plurality of spaced pivotally mounted vanes, with the adjustment of the angle of the vanes determining the direction and volume of air flow. The structure employed to provide for pivotal mounting of the vanes and the mechanism for effecting vane adjustment is relatively complex and costly, and is subject to breakdown.

Attempts have been made to reduce cost and likelihood of breakdown by forming the vanes in a fixed position in a single integral unit in which turning of the vane unit provides for a change of air direction. Volume flow rate control is however not possible by simple rotation of the vane plate and auxiliary dampers are required if flow rate control is desired, again resulting in an increase in cost and complexity of mechanism, leading to likelihood of breakdown.

Additionally, perennial problems with the previously employed air diffusers have arisen from the entrainment of dirt in the conditioned air stream with deposit of this dirt as smudges on the surface areas surrounding the air discharge openings of the diffusers.

BRIEF DESCRIPTION OF INVENTION

It is with the above considerations in mind that the instant invention has been evolved providing a simple efficient selectively and, if desired, automatically controlled variable volume flow rate air diffuser in which air volume flow rates and distribution paths may be selectively controlled depending on desired conditions, with little or no smudging of the surfaces in the conditioned areas surrounding the outlets of the diffusers.

It is accordingly among the objects of this invention to provide a simple air diffuser subject to fabrication at relatively low cost and simple to use and maintain.

A further object of the invention is to provide an air diffuser minimizing smudging of surface areas adjacent the discharge opening of the diffuser when operatively positioned.

Another object of the invention is to provide an air diffuser which may be selectively adjusted to control the volume flow rate of air flow.

An additional object of the invention is to provide an air diffuser which may be selectively adjusted to provide air flow patterns directing air from the diffuser to one side, two sides, three sides or four sides of the diffuser outlet.

These and other objects of the invention which will become hereafter apparent are achieved by forming the diffuser with a duct having an outwardly flared portion leading to the air discharge outlet of the diffuser. Arranged in the air flow path through the outwardly flared portion of the diffuser duct is a perforated plate mounted on a support shaft so that the perforated diffuser plate may be shifted along the axis of the duct flow path to bring the plane of the diffuser plate closer to or further from the plane of the discharge outlet as a result of which dampering of the air flow is obtained to control volume flow rate of flow. Additionally, the position of the damper plate with respect to the outlet will control lateral deflection of the air stream at the outlet. By forming the damper plate with a slot at its point of securement to the support shaft, the damper plate may be laterally shifted with respect to the duct axis so that the dampering effect will be greater at certain portions of the air stream than others to thereby produce a deflection of discharge of air from the outlet, thus providing for selective control of air discharge patterns. By employing two perforated damper plates, one shiftable over the other, the steps in the range of selective control of distribution pattern may be increased.

A feature of the invention resides in the use of a perforated damper plate to permit some primary air flow through the damper, thus minimizing smudging.

Another feature of the invention resides in the fact that by the use of a simple perforated plate formed with a slit at its point of attachment to an axially shiftable supporting shaft, the threefold functions of 1) volume flow rate to achieve air balancing; 2) pattern control; and 3) smudge elimination may be attained.

BRIEF DESCRIPTION OF DRAWINGS

The specific details of the invention and how to make and use same and the best mode contemplated of carrying out the invention will be described in clear concise and exact terms in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic elevational view through a diffuser embodying the inventive concept;

FIG. 2 is a view on line 2--2 of FIG. 1 looking down on the damper plate showing a preferred mode of supporting the damper plates in the diffuser duct;

FIG. 3 is a view on line 3--3 of FIG. 1 looking up at the diffuser outlet above the plane of the outlet grid face plate;

FIG. 4 is a schematic view showing an arrangement of the damper plates to provide for air distribution over a 360.degree. diffusion path;

FIG. 5 shows the damper plates laterally shifted in the discharge duct to provide three-way distribution such as would be desired where the diffuser is adjacent a wall;

FIG. 6 shows an arrangement of two damper plates oriented to provide two-way distribution such as would be desired in a corner installation of the diffuser;

FIG. 7 shows a two damper plate arrangement providing two-way opposite distribution, such as would be desired in a narrow corridor;

FIG. 8 is a schematic view of a pair of damper plates shifted to a position providing for one-way throw of the distributed air stream such as may be desired at the end of a corridor; and

FIG. 9 is a schematic elevational view of another embodiment of the inventive concept in a diffuser provided with means for automatically controlling volume flow rate.

DESCRIPTION OF PREFERRED EMOBIDMENTS

Referring now more particularly to the drawings, like numerals in the various FIGS. will be employed to designate like parts.

As shown schematically in FIG. 1, the air diffuser 10 embodying the inventive concepts is illustratively shown as formed with a duct 11 defining an air flow path 12, which as understood by those skilled in the art, flows downwardly in the schematically illustrated diffuser 10 from an air supply source such as air conditioning or heating equipment. Duct 11 is formed with an outwardly flared portion 14 leading to diffuser outlet 16, which is illustratively shown as provided with a grid face plate, which as understood by those skilled in the art, is of a perforate construction.

The diffuser duct 10 is preferably formed of sheet metal and is illustratively shown as circular in cross-section transitioning after flared duct portion 14 to a rectangular face 20 underlying grid face plate 18.

Duct 11 is formed in the illustrated embodiment with a circumferential dimple 23 for supporting a spider support 25.

Spider support 25, as best seen in FIGS. 1 and 2 is formed with three arms 26, 27 and 28 each contoured at its end with a curve to engage duct dimple 23. Arms 26, 27 and 28 extend from triangular center plate and support this center plate 29 in a plane transverse to the longitudinal axis of duct 11 with the center of plate 29 lying on the longitudinal axis of duct 11. An internally threaded opening 32 is formed at the center of plate 29, and a threaded support shaft 34 is screwed into this opening 32 to permit selective adjustment of the degree of insertion of shaft 34 in plate opening 32.

The lower end of support shaft 32, as best seen in FIGS. 1 and 3 is formed with a threaded recess receiving machine bolt 35 which serves to retain a lower washer 37 on shaft 34.

A perforated damper 40 is mounted on shaft 34 above lower washer 37 as best seen in FIG. 1. Damper 40 is preferably formed of a configuration approximately the cross-section of duct 11 immediately after transition into flared duct portion 14, so that when support shaft 34 is screwed into spider plate aperture 32, the damper will be brought up to a portion extending substantially over the air flow path through duct 11. In the illustrated embodiment damper 40 is in the form of a circular plate with a diameter slightly larger than the internal diameter of duct 11.

Damper 40 is formed with a plurality of perforations 42 distributed over the area of the damper, and is provided with a central radially extending attaching slot 45 of a width slightly larger than the thickness of support shaft bolt 35 and less than the diameter of washer 37, so that damper 40 may be freely slid laterally with respect to shaft 34. Slot 45 is preferably selected of a length such that damper 40 may be laterally shifted from a position coaxial with that of the duct 11 to a position tangent with the flared duct portion 14.

In the embodiment of the invention illustrated in FIGS. 1-8, a second perforated damper 50 is provided overlying first above described damper 40 which is identical to damper 40. Top washer 52 overlies top damper 50 as seen in FIG. 1 to sandwich and maintain dampers 40 and 50 on support shaft 34.

In the embodiment of the invention schematically shown in FIG. 9, volume flow rate is automatically obtained by use of a motor 60 to position damper support shaft 34. An air motor such as Robert Shaw motor model M552 may be satisfactorily employed with the damper support shaft 34 coupled to the motor shaft to effect shifting of the damper plate along the axis of flared portion 14 of duct 11.

OPERATION

In use, the above described air diffuser is installed in conventional fashion in an area where air is to be directed, with the diffuser usually arranged in the ceiling of the area and coupled to conventionally employed ductwork employed in directing air from air conditioning or heating equipment to the area.

Volume flow rate of air, and air distribution patterns from the diffuser are selectively controlled by selective positioning of the damper 40, alone where one damper is used, or by selectively positioning both dampers 40 and 50 where two dampers are used.

In using a single damper 40, the volume flow rate of air flow is controlled by positioning the damper at a greater of lesser distance from the throat of duct 11 formed at the transition of the duct 11 to flared duct portion 14. Thus, at the extreme upward position of the damper as viewed in FIGS. 1 and 9, there will be maximum throttling of the air stream with mimimum volume flow rate of air, while at the lowermost position of the damper as viewed in FIGS. 1 and 9, throttling will be at a minimum and the volume flow rate of air at a maximum, with intermediate damper positions providing volume flow rate of between maximum and minimum.

Selective positioning of the damper between the aforedescribed positions of maximum and minimum flow is accomplished in the FIG. 1 embodiment by turning threaded support shaft 34 to screw it further into or out of engagement in threaded support plate aperture 32.

In the FIG. 9 embodiment, actuation of motor 60 serves to move damper support shaft 34 axially.

In order to selectively vary air distribution paths, the damper may be laterally shifted with respect to the axis of the duct, so as to throttle one or the other side of the air flow path thereby deflecting the air stream.

Where a single damper 40 is employed, the air distribution pattern may be of a four-way type as shown in FIG. 4 by positioning the damper coaxially with the duct. Should deflection of the air stream be desired to a side of the diffuser, the damper 40 is laterally shifted along slot 45 after screw 35 is loosened, with the damper shifted to the side of the diffuser opposite to the side from which air flow is desired, as schematically shown in FIG. 5.

A greater degree of selectivity of distribution patterns can be obtained by utilizing two damper plates 40 and 50 as illustratively shown. Thus two-way throw such as might be desired at a corner installation of the diffuser can be obtained as shown in FIG. 6 by orienting the slots 45 of the dampers 40 and 50 at right angles to each other and shifting the dampers laterally with respect to support shaft 34.

Where two-way opposed throw of the air stream is desired, as may be required of a diffuser positioned in the center of a corridor, the dampers 40 and 50 are laterally shifted in opposite directions as shown in FIG. 7.

Constrained one-way air throw as may be desired from a diffuser at the end of a corridor is obtained by orienting the dampers 40 and 50 as shown in FIG. 8.

It will be apparent to those skilled in the art that a variety of structures may be employed to support the slotted perforated dampers in the diffuser duct subject to selective movement of the dampers, shifting the dampers laterally to effect air distribution patterns, and moving them axially to regulate air volume. In the illustrated preferred embodiments a simple structure has been provided in which lateral shifting of the dampers is accomplished simply by loosening screw 35 freeing dampers 40 and/or 50 so that they may be slid laterally along slot 45. After a given desired damper position is obtained, screw 45 is tightened to securely grip the dampers between washers 37 and 52 at the end of support shaft 34. Axial movement of the dampers to adjust rate of volume flow is effected by screwing shaft 34 with respect to spider plate 29. Suitable lockwashers may be employed to fix the position of the shaft 34 with respect to plate 29. Axial movement of the damper support shaft 34 may also be effected automatically as in FIG. 9 by use of a motor 60.

It will be noted that the perforations 42 in the damper serves to breathe some of the primary air from the diffuser through the damper plate and also through the perforated face plate 18 of the diffuser. It is found that this breathing of the primary air serves to minimize smudge accumulations on the surface areas of the diffuser outlet. This appears due to the fact that the flow of primary air through the diffuser perforations projects below the diffuser surface meeting the upward flowing ambient air preventing the ambient air from reaching and depositing dirt on the surface of the diffuser.

It has been found that in utilizing two damper plates 40 and 50 with perforations in the plates of substantially equal size and spacing, that the volume air flow rate remains substantially the same when one damper plate is shifted with respect to the other, since through throttling a greater portion of duct cross-section, the flow rate through the single layer of damper plate is increased.

It is thus seen that applicant has provided a relatively simple, inexpensive and easily maintainable air diffuser serving to permit selective control of volume flow rate, and air flow patterns, and minimizing smudges on surfaces adjacent the diffuser.

The above disclosure has been given by way of illustration and elucidation and not by way of limitation and it is desired to protect all embodiments of the herein disclosed inventive concept within the scope of the appended claims.

Claims

What is claimed is:

1. An adjustable flow air diffuser comprising: a duct defining an air flow path, said duct having an outwardly flared truncated conical portion leading to an air discharge outlet formed with spaced openings therein; a perforated damper plate positioned in said truncated conical portion at a spaced distance from said outlet with the plane of the damper plate lying across the axis of flow of air through said duct, said damper plate having a radially extending slot; and a support shaft supporting said damper plate for selective movement along the duct axis within the axial distance defined within said truncated conical portion, said damper plate sildeably connected to said support shaft at said radially extending slot to permit selective radial shifting of said damper plate in the air flow path.

2. An adjustable flow air diffuser as in claim 1 in which a second perforated damper plate substantially identical to said first mentioned plate is arranged in a plane parallel to that of the first mentioned damper plate, and both are slideably connected to supporting means.

3. An adjustable flow air diffuser as in claim 1 in which said damper plate has a cross-sectional area greater than the minimum cross-sectional area of said duct, and is movable in the axial region of said truncated conical portion.

4. An adjustable flow air diffuser as in claim 1 in which said duct and outwardly flared portion are circular in cross-section, and said damper plate is circular.

5. An adjustable flow air diffuser as in claim 1 in which said duct and flared truncated conical portion are circular in cross-section; and said means supporting said damper plate comprise: a plurality of arms engaging the interior of said duct and a plate having a threaded opening is supported by said arms, said plate lying in a plane transverse to the duct axis, and a threaded support shaft in said opening, said shaft subject to being screwed into or out of said opening; said damper plate having a slot, a screw extending through said slot into engagement with the end of said shaft; and a second slotted damper plate secured to said shaft by said screw, whereby the two damper plates may be adjustably positioned to control the position and size of a flow opening between the two damper plates and the truncated conical portion.

6. An adjustable flow air diffuser as in claim 1 in which the perforations of said damper plate are smaller than the openings of said discharge outlet.

7. An adjustable flow air diffuser as in claim 2 in which the perforations of said second damper plate are of a size and spacing similar to the perforations of said first mentioned damper plate.