US2432289A - Ventilating system - Google Patents

Description

Dec. 9, 1947. G. s. DAUPHINEE VENTILATING SYSTEM 2 Sheets-Sheet 1 Filed Sept. 8, 1943 e v mm W /NW/ N r w m M 8 e 7%. 0 e G Y B r G.'s. DAUPHINEE 2,432,289

VENTILATING SYISTEM Filed Sept. 8, 1945 2 Sheets-Sheet 2 IN VEN TOR. Ge 07 96 S. Dauph inee Figure 5 is a plan view of one of the sectorizing bars according to the invention, and

Figure 6 is a side View thereof.

Through the drawing the same reference characters serve to indicate the same or analogous parts.

Referring in greater detail to Figures 1 and 2, the enclosure shown therein embodies a ceiling A, a floor line B andwalls C. The center columns E as well as the wall columns F are spaced an equal distance apart and for the purpose of this description the standard spacing of 20 feet has been selected. The diffusers G are set into the'c iling Aand connected to the supply ducts I and are located in the center of the squares or bays defined by the column centerlines. (See Figure 2.)

The diffused or deflected air in areas in accordance with present day practice are in the form of complete circles or discs. Accordingly great care has to be taken to prevent these discs from unduly overlapping or colliding by choosing the energy factors (volume and exit velocity), of the supply stream so that this energy will be well spent at the points of contact. Radial flow velocitiesatpoint of contact over 50 feet per minute will generally cause objectionable drafts. This flow area is of disc formation, relatively thin and hugging the under surface of the ceiling. This general form of air flow is common to all diffusers designed for low ceiling surface. In high buildings it might of course be. desirable to difiuse the air more downwards.

.It will be seen from Figure 1 that the primary ordiffused air stream as it leaves the diffuseris augmented by aspirating the layer of room air directly below the discharge disc throughout its course. Thusythe direction of the air currents or' air movements directly below the discharge disc is vertically upward over the full area of the disc and downward at the corners of the squares or bays; In this manner a continuous circulatory movement is established throughout the enclosure: 1 g v Theintensity of the upward movement is maximum at the origin of the discharge stream and gradually'diminishes to zero at the outer circumference of the'disc. Taking the proportions indicated it will be seen that the upward flow area is l0 0 1r or 314- square feet. Accordingly, the remaining area of ;the square providing for the downward flow of the entire stream as augmented by the aspirated room air is only 400314;86 square feet. Therefore,- the velocity of the downwardflow is many times greater than the velocity of theg eneral upward direction.

Now, if the energy factor of the stream is increased (mass velocity) the discs will overlap and the downward flow area will become still smaller and consequently the velocity of the downward flow will be still further increased resulting vin highly objectionable drafts. Downward drafts will also occur where the discs overlap as the velocity at impact will now be greater than 50 feet per minute. The foregoing xplanations are given for the purpose of illustrating the limitations upon the rate of air supply to standard building constructions. It might be suggested to increase the mass and lower the velocity and still maintain the same energy factor (mv.) but this doesnot appear to help the elfective draft condition as the mixing effect or temperature equalization diminishes with an increase of M within th limited throw space, as the augmentation'rate depends on the area of contact between the surface of the discharge stream and the room space. Therefore, by increasing the volume or mass of the initial stream and confining it to the 10 foot throw, the percentage of possible temperature equalization will be decreased as compared with the lower mass or volume.

The objects of th invention are accomplished by dividing the radial flow areas or discs into a series of sectors as shown in Figure 2 of the drawing. In each alternate sector a, the original or conventional radial flow is maintained as indicated by the broken line whereas in sector I) eddies prevail producing a combination of upward and downward currents, having a general radial drift outward and downward. The depth of this area is therefore much greater than that of area a. Hereafter area b will be referred to as the turbulent flow area or sector in contradistinction to area a which .will be referred to as the radial flow area or sector. In some instances it has been found advantageous to stagger the sectors of adjoining radial flow areas or discs so that un-like sectors oppose each other along the common centerline of the discs. In this manner downdrafts are avoided at the points of overlap. In other words, the Velocity of the discharge streams may be increased without the harmful effect of the overlap in the conventional installations.

Again, in the turbulent sectors, especially throughout the outer areas, the balance between the forces promoting radial flow become less than those promoting downward flow. Accordingly, downward flow will take place in these outer areas thereby relieving the tendency for high Velocity at the corners of the bays.

It has been found that the sectorization of the radial flow areas increases the mixing effect and the resultant temperature equalization within the limited space. The number of sectors may vary. Although eight forced flow sectors and eight turbulent sectors are shown in the drawing, as few as four sectors of each may be used where draft conditions are less accentuated. Conversely, the number of sectors may be increased when the conditions so require.

Referring in detail to Figures 3 and 4, the diffuser employed in connection with the invention comprises a casing. or dome ll] having a neck portion for connection to the supply duct I. The casing 10 is preferably provided with an annular deflector surface l2, against which the supply stream will impinge so as to be slightly deflected thereby, and a dished rim or bead portion I3 engaging the undersurface of the ceiling.

In connection with the. reference to deflector surface l2 above, it might be pointed out that under normal operating conditions the extent of downward deflection produced by part [2 does not materially change the direct radial disc formation along the, ceiling as indicated in Figure l but merely retards contact of the stream with the ceiling to a point where the velocity is decreased below that sufficient to throw. out dust particles and'to cause smudging of the ceiling surface. The effect of the'ceiling on flush set diffusers to draw the stream .upward is so great'that the entire air volume must be initially deflected downward as much as 45 deg. to prevent it producing a low pressure area at the ceiling surface sufiicient to draw itself upward.

The inner assembly of the diffuser comprises one or more deflector members l4 and I5 which are spaced from the casing l0 and from one another to define discharge passages 16 and I1 therebetween. l f

The division or sectorization of the radial flow areas or? discs is accompli shed by means -thg clips or bars L8. arepgsitiq abeutthe extrem out r endof th d schar passage 16 across he. dis har e. imam. It. i s ra le. t nhcethesebars, or clips asnear the outerend; o the passage snossi le. If placed upward the passage the dividedstream will merge again. For best. results. the bars. should curve outward and bulge slightly downward, Eurthermore even though the width of the blanking clips 18 is not critical to the invention, it, should be understood that. their mustpossesssufficient. width seas to blank. oirsuchnorti n of: the. discha e area as to. d vide. the. di ch rge stream into altern tensed fiowsectu and turbulent sectors. Thus t h en found. thatthe blanking-clips ltshould be at least so wide that they blank off about of the area of the discharge opening. Beyond this lower limit, the width may vary depending upon the number of sectors desired and the particular conditions to be met.

The bars [8 may be so designed that they may be snapped into place intermediate the deflector surface l2 and the bead 2i of the deflector member M. For the latter purpose, the bars are provided with a hook 22 at one end which easily may be bent about the bead 2i. In this manner, the position of the bars about the discharge opening may be easily changed at will. This adjustable feature is important for example where large or bulky machinery is changed toa new position within the area served after the installations of the diffusers and which might alter the pattern of air distributions and set up drafts. By adjusting these bars, these conditions can be easily remedied.

It has also been found that when the diffuser has two or more discharge passages, the sectorization is eifective if these bars I8 are placed in the main or upper passage only, as the air from the lower passages has a tendency to be drawn upwards to merge with the main stream and, when the upper stream is sectored, the lower stream or streams will be to a large extent divided and merge with the sector in which the radial flow'is maintained. In some instances, the lower discharge passes may be eliminated entirely.

It Will be understood that this disclosure is given by way of example and not by way of limitation. On the other hand the invention may lend itself to a variety of expressions within the scope of the appended claims.

What is claimed is:

1. An air or gas diffuser comprising a casing for connection to a supply duct and a deflector member spaced with respect to said casing to define a tubular discharge passage therebetween, means mounted at the outlet opening of said discharge passage for blanking off a portion of said outlet opening and prevent discharge through said portion, said means having a flat surface normal to the discharge stream and such surface having at least such a width that said blanked off portion will not be less than 5% of the area of said outlet opening, whereby the discharge stream will be divided into alternate forced directional flow areas and turbulent areas.

2. An air or gas diffuser comprising a casing for connection to a supply duct and a deflector member spaced with respect to said casing to define a tubular discharge passage therebetween, and means mounted at spaced intervals transversely across the outlet opening of said discharge passage for blanking off a portion of said outlet; openin p erentd schareel through said passage, said means having a flat; surface normal to the discharge, stream and said surface having at least such width that said blanked ofi portion will be not less than 5% of the area of sa d utl t penin W r br the dis har e stream will be'divided into alternate fenced rectional flow areas and turbulent areas.

3. An air or gas diffuser comprising a casing for connection to a supply duct and a deflegtgr; mem er seat with rssneet o s eat 0 define an annular discharge passage t be twte t aeen j esum d. acr s t e. t-e 95 9 alt- 1% d cha g Pd fi f? for 21.

ef re P tia-L o s u l pe in d i vsa th ou h n re'ss se. sai e tit 1?? fishli z fi 938% P9 hfltllfip 3H and said surface having at least such width that said blanked off portion will be not less than 5% of the area of said outlet opening, whereby the discharge stream will be divided into alternate forced directional flow areas and turbulent areas.

4. An air or gas diffuser comprising a coneshaped casing for connection to a supply duct and a deflector member spaced with relation to said casing to define an annular discharge passage therebetween, and a plurality of outwardly and downwardly curved blanking members positioned intermediate the outer ends of said casing and said deflector member and extending below the outlet opening of said discharge passage at spaced intervals about said outlet opening for blanking off a portion of said outlet opening and prevent discharge through said portion, said blanking members having a flat surface normal to the discharge stream and said surface having at least such Width that said blanked off portion will not be less than 5% of the area of said outlet opening, whereby the discharge stream will be divided into alternate forced directional flow areas and turbulent areas.

5. In a ventilating system for a room or similar enclosure comprising a plurality of diffusers each connected to a supply duct and spaced re ularly along the Ceiling of said enclosure, each of said diffusers comprising a relatively spaced casing and a deflector member defining a tubular discharge passage therebetween, means mounted at the outlet opening of said discharge passage in each of said diffusers for blanking off a portion of said outlet opening and prevent discharge through said portion, said blanking means having a flat surface normal to the discharge stream and said surface having at least such width that said blanked oif portion will be not less than 5% of the areas of said outlet opening, whereby the discharge stream will be divided into alternate forced directional flow areas and turbulent areas, said blanking means being so arranged that the turbulent areas of adjoining diffusers will oppose the forced flow sector on the common centerline of said radial flow areas.

6. An air or gas diffuser for connection to a supply duct, said diffuser having an annular discharge passage for diffusing the supply stream radially, means mounted transversely across the outlet opening of said discharge passage and extending beyond said outlet opening for blanking off a portion of said outlet opening and prevent discharge through said portion, said means having a flat surface normal to the discharge stream and said surface having at least such width that said blanked off portion will be not less than 5% of the area of said outlet opening,

whereby the discharge stream will be divided into 7 alternate forced directional flow areas and turbulent areas.

" GEORGE S. DAUPHINEE.

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

UNITED STATES PATENTS Number Number Number Name Date 1,642,479 Barthel et a1 Sept. 13, 1927 2,240,617 Harrigan May 6, 1941 2,301,045 Heath Nov. 3, 1942 2,148,254 Bergstrom Feb. 21, 1939 2,262,243 Lord Nov, 11, 1941 2,106,458 Kurth Jan. 25, 1938 2,144,631 Kurth Jan. 24, 1939

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