US2758822A - Air tempering and distributing units - Google Patents

Description

Aug. 14, 1956 K SAUTER 2,758,822

AIR TEMPERING AND DISTRIBUTING UNITS I I Filed Sept. 25, 1953 3 Sheets-Sheet l FIG. FIG. 3.

INVENTOR KARL SAUTER ATTORNEY llg. 14, 1956 K SAUTER 2,758,822

AIR TEMPERING AND DISTRIBUTING UNITS Filed Sept. 25, 1953V 3 Sheets-Sheet 2 4Q FIG. 5.

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u r r l r i f i a INVENTOR K AR L SAUTE R BYm ATTORNEY Aug. 14, 1956 K. vSAUTER AIR TEMPRING AND DISTRIBUTING UNITS 3 Sheets-Sheet 5 Filed Sept. 25, 1953 FIG. lo.

INVENTOR KARL SAUTER y BY ATTORNEY United States Patent AlR TENIPERING AND DISTRIBUTING UNITS Karl Sauter, Vitikon A/A, Switzerland, assignor to Luwa 'S. A., Zurich, Switzerland Application September 25, 1953, Serial No. 382,267

2 Claims. (Cl. 257-137) This invention relates to air tempering and distributing units for air conditioning multi-room buildings.

The general object of the invention is to produce comfortable atmospheric conditions during all seasons of the year by utilizing a conventional central station system of minimum capacity for supplying primary, intensively conditioned, outdoor air for ventilation purposes, plus individual units positioned in the conditioned rooms, said units being designed to utilize the primary air for inducing relatively large volumes of secondary or room air, the primary and secondary air forming mixtures which are tempered as desired at the units.

The features of the invention which make applicants system superior to those heretofore employed include: (l) sensible heating or cooling of a mixture of primary and secondary air rather than of secondary air alone, (2) sensible heating or cooling at the units in the rooms without resort to the usual separate, finned, coil positioned in the path of the secondary air, (3) use of the units for maximum efliciency without need for a casing or other enclosure heretofore necessarily provided, (4) use of substantially the whole of the unit structure as a heat exchanger, (5) use of the unit structure, to a substantial degree, as a radiator, (6) use of surfaces of the unit to provide, in substantial degree, radiant heating or cooling effect, (7) the use ofA a unique cellular structure to enable easy access for effective cleaning, (8) provision of a compact and inexpensive cooling, heating, and air distribution unit combined in a single, simple, package, (9) provision of a unit with a multiplicity of coils adapted to route heating or cooling fluid through different of said coils at different times, as desired, without possibility of contaminating the source or sources of supply of uid serving the coils, (l) design comprising a plurality of separate air passages for mixtures of primary and secondary air, which minimizes noise resulting from primary air discharge, induction of secondary air and passage of the mixture of primary and secondary air through the units, (ll) higher induction ratio of secondary to primary air than heretofore produced, with the result that less power is required for the primary air which is discharged at a lower noise level.

Other advantages of the invention including ease i-n manufacture, compact and simple assembly, use of minimum oor space, adaptability to fabrication in different sizes and lengths, and ready application for a Wide variety of uses will also be apparent from the following specications of illustrative forms of the invention, shown in the accompanying typical drawings:

Fig. 1 illustrates diagrammatically one form of applicants unit;

Fig. 2 is a section on the lines 2 2 of Fig. l;

Fig. 3 is a fragmentary, enlarged section of a portion of the unit of Fig. 1;

Fig. 4 is a fragmentary section on the lines 4 4 of Fig. 2;

Fig. illustrates diagrammatically another form of 2,758,822 Patented Aug. 14, 1956.

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2 unit, employing a differently arranged conditioning element;

Fig. 6 is a section onthe lines 6 6 of Fig. 5;

Fig. 7 is a fragmentary, enlarged section of a portionof the unit of Fig. 5;

Fig. 8 is a fragmentary section on the lines 8 8 of Fig. 6;

Fig. 9 shows, in perspective, a fragmentary View of a segment adapted to be compounded as desired to form a unit of desired length;

Fig. 10 shows a diagrammatic section of one form of sandwich construction employed by applicant to provide an inexpensive unitary structure providing a plurality of passages, served by primary air nozzles, and embracing secondary conditioning means which enables all walls of the passages to become a heat exchanger;

Fig. l1 shows one of applicants units positioned under a window;

Fig. 12 shows a variation in unit structure wherein parallel passages are also shown but served by a plurality of nozzles,

Fig. 13 shows diagrammatically a section of one form of unit equipped with electrostatic filtering means;

Fig. 14 shows a fragmentary section of one form of unit wherein parallel passages are equipped with a plurality of nozzles, the passages being interconnected; and

Fig. 15 shows a preferred form of nozzle used in applicants unit.

Referring to the drawings, lirst with reference to Figs. 1-4, it will be understood that unit A is employed in an individual room of an oflice building, hotel, or similar structure wherein a central station air conditioning system serves a plurality of such units located throughout the many rooms to be occupied. Such central station system, when used with applicants units, is relatively small and designed to condition intensively a desired volume of primary air, usually, although not necessarily, outdoor air suicient to take care of ventilation requirements, of the whole building.

The central'station system is not illustrated, since it may be of conventional form. Such system supplies the primary air at relatively high velocities, on the order of 4000-6000 feet per minute at a static pressure in excess of 1 water gauge. The primary air, because of its relatively small volume, discharged at relatively high velocities and static pressure may be distributed to applicants units through relatively small ducts or conduits.

Units such as A are preferably vertically positioned below a window as shown, for example in Fig. 1l, but, for different purposes, may be located in any desired position to serve. a given area.

As illustrated in Figs. 1 4, the air from the central station system enters unit A through conduit i7, in which volume control device 18-is provided, the air entering plenum chamber 19 and being discharged through nozzles 20.

The nozzles 20, as shown in Fig. 15, are in the form of slender tubesv with passages therethrough on the order of l; inchto 1A inch in diameter at the tip, although no limitation isy made with respect to size of passageway, since this depends on the `relation of size of nozzle with respect to size of tube served thereby. The nozzles may be made of metal, plastic, or other material, and are mounted on nozzle plate 22 whichmay suitably be fastened at the top of the plenum chamber, the air entering the nozzles from the chamber through the plate.

Nozzles 20 project upwardly into the unit, and as shown in Fig. l, the tips of the nozzlesneed not project b'eyond thebottom of tubes 23. will hereinafter be described, the nozzles do project into tubes of. theunit; and` in different applications it may be desirable to provide nozzles whichwill terminatetatdifln unit B of Fig. 5, as,

ferent levels with respect to the entrance ends of tubes served thereby.

The body of unit A is preferably made up of a series of identical longitudinal segments 24 open at both ends. As shown in Fig. 9, each segment 24 consists of an H- shaped metal extruded section with a pair of extensions 26, forming a housing for a cooling or heating coil 27 which is in intimate, close contact with each segment, but located between the series of tubes 23 formed by connecting together a series of segments.

Thus, applicant provides two series of unobstructed tubes with a coil positioned therebetween, as shown in Figs. 2, 3 and 4, with the coil 27 making contact with the segments 24 at contact areas 28. While the segments are tted together with male and female joints 29, it will be apparent that such segments may be tightly joined in other suitable ways to form a series of longitudinal tubes 23, in parallel arrangement one with respect to the other, each served at the bottom by a nozzle 20.

In the structure shown in Fig. 9, the segments are in the form of extruded metal shapes, but applicants tubes could readily be made of other forms, such as Channels, U shapes, and the like, joined together to form a series of parallel tubes in combination with a coil adapted to sensibly heat or cool the metal comprisingy such tubes.

Thus, in Fig. l0, there is provided a central coil section 30, flanked on each side by a series of tubes 23. In this structure, confining plates 32 are subdivided into tubes 23 by zigzag metal sections 33. Such sections 33 may be in one or more pieces to form tubes. While tubes 23 of Fig. 10 are substantially triangular in shape, they may be square, rectangular semi-circular or other desired form as will best Serve the needs of the unit. In practice, the plates 32, sections 33 and coil 27 (of central coil section 30) may be soldered or brazed together so that the central coil section and either one or two adjoining zigzag metal sections (which form the tubes 23) may be formed into a single, self-contained unit. Of course, if desired, only one series of tubes may be used with a coil section rather than two series of tubes with a coil in between. The important point is that a series of tubes, through which a mixture of air passes, is in contact with a coil which controls the temperature of the walls of the tubes.

The coil 27, under summer operating conditions, admits cooled liquid, usually water at a temperature higher than the dew-point temperature of the air passing through tubes 23, at valve 34. Under winter operating conditions, heated water will enter the coil through the same valve 34. Suitable piping and valvearrangements are provided at the central station system to supply such liquid at desired temperatures; and valve 34 may be so arranged with suitable indicating plates so that an occupant of the room served by the unit may control the valve to obtain more or less heating or cooling through the opening or closing of the valve.

In Figs. -8 a modified form of unit is shown, wherein a metal segmented radiator structure of known form has its open ends closed by cover sheets 36 to form tubes 23. Conditioning liquid, as in the case of unit A, enters unit B (Figs. 5 8) through valve 34 into a distributing header 37, then flows in parallel paths through the passages 38 to discharge header 39 and back to the piping system which returns to the central station. Therefore, in this structure too, a plurality of parallel air tubes 23, served by nozzles 20, is heated or cooled by the liquid owing through contacting passages 38.

It will be noted that in the arrangements of units A and B, the upward passage of air through tubes 23 is in counterow direction to that of the conditioning liquid.

The nozzles 20, serving unit B, project to diierent degrees into tubes 23, but the resultant effect in both units A and B stems from the same principle of operation.

The discharge of primary air at relatively high velocity and pressure from nozzles into tubes 23 will cause the induction of secondary air into the tubes 23, and the induction ratio in applicants units is on the order of l to 3 up to l to 10. Thus, as much as l0 times the volume of primary air discharged from nozzles 20, will enter the tubes from the atmosphere surrounding the unit. The resultant mixture rushes upwardly, through tubes 23, in highly turbulent, agitated, condition to be discharged therefrom at their top openings 40 into the room. The heat exchange between the turbulent mixture passing through the tubes and the tempered walls of the tubes, affected by the coil 27, results in highly effective sensible heating or cooling of the mixture.

However, with applicants construction, the primary air need not necessarily be discharged through the nozzles at high pressures but may, for example, be discharged at a pressure less than l water gauge and yet have a satisfactory induction ratio.

Since the tubes are either cooled or heated by coil 27 (as in Figs. 1-4 and 10) or by structure 35 (as in Figs. 5-8), such tubes together with their associated heating and cooling means form a heat exchanger for tempering the mixture of primary air (from nozzles 20) and secondary air (induced from the surrounding atmosphere) flowing through the tubes. This is of great importance. The mixture as a whole is thereby tempered and not the secondary air alone, as has heretofore been the case by providing a coil separate from the unit through which only secondary air passed. Also, the unobstructed tubes 23 are kept relatively clean by the rush of air therethrough and such dust as may accumulate is readily cleaned by simple brushing; and since the coil is not exposed to any flow of air, it is not subject to dust or dirt accumulation.

As shown in Fig. 1l, the unit may be positioned below a window, with the top of the unit substantially at sill level. As shown, the discharged mixture will ow adjacent the glass area, as is highly desirable to cornpensate for leakage and heat transmission. But equally, if not more important, is the action of the unit in providing a negative pressure at the nozzle level. The result is a withdrawal or sucking of air, as shown by the dot-dash line, from the sill area, downwardly for induction into the tubes. Consequently, such air, of undesirable condition, is removed for tempering before it can substantially adversely affect room conditions.

The use of a series of joined sections, equipped as desired with suitable end or finishing pieces, enables applicant to place his unit directly within a room, Without necessity for cover, casing, or concealing cabinet work. Since the entire unit constitutes a heat exchanger, with the front or exposed surface which faces the room forming in the nature of a radiant heating or cooling panel, the unit thereby provides desirable radiation efect in addition to supplying conditioned air.

Applicant has found as a result of intensive research, that his tubes and nozzles should preferably follow certain principles with respect to their relative dimensions. The hydraulic diameter of each tube should preferably not exceed 6G millimeters, and this should be calculated in accordance with the formula 4 tube cross-sectional area tube periphery the cross sectional area of the tube, being measured at the outlet thereof. Further, the length of each tube should preferably be in excess of ve times the hydraulic diameter. Also, the sum of the cross-sectional areas at their tips of all nozzles used with a series o-f tubes, should preferably be less than one-fifth of the sum of the crosssectional areas of all tubes (measured at the outlets thereof) used with said nozzles. However, applicant does not restrict his invention to these design limit-ations.

Figs. 12-15 show a number of modifications which may be used with different forms of applicants units.

ln Fig. 12, tubes 23 are each equipped with a pair of nozzles 20. The coil 27 is in contact with body portion 41 which has a plurality of ':xtended fins 42 to increase heat exchange efiiciency by providing increased surface for contact with the mixture of primary and secondary air passing through tubes 23.

Fig. 13 shows a unit in which dust may be extracted from the mixture of air flowing through tubes 23. Suspended from supports 4.5 are electrodes 46 of an electrostatic iilter which project into tubes 23. The walls 43 of the tubes serve as deposit electrodes and are grounded by conductor 44.

Fig. 14 shows a plurality of tubes 23 each served by a pair of nozzles 20, the tubes being interconnected by passages 47. Such structures may more economically be fabricated for certain applications where castings or other shaped members may be acceptable.

While applicant has exemplified specific forms of his invention, it must be pointed out that innumerable vari ations are possible for achieving an equivalent result. The primary object, achieved by applicant, is the provision of an inexpensive, highly eliicient interchanger, adapted to be used as a self-contained unit for conditioning a large mixture of primary and secondary air to heat or cool a given area and at the same time take care of its full circulation requirements as part of an air conditioning system. However, applicants self-contained unit may effectively be employed simply to condition primary air; or as a convector heater (and radiator) as part of a heating system; or as part of an air conditioning system used only for heating punposes without primary air supply; and said unit may also be employed as desired as an air distributor, or in combination, for example, with a refrigeration system to serve an evaporator or condenser; and hence, applicant makes no limitation with respect to manner of use.

Furthermore, while the walls of the tubes are usually solid throughout, nevertheless, if desired, apertures or slits may be provided at different points in the walls to afford induction at a plurality of points rather than at the bottom alone; and, similarly to provide discharge at a number of points rather than at the top alone.

I claim:

1. An air tempering and distributing unit for connection to a central source of conditioned air which supplies primary air at a high velocity to the unit, comprising a first longitudinal wail, a second longitudinal wall spaced from and extending parallel to said first wall, a lirst set of longitudinal and transverse partitions forming with said first wall a first row of aligned, open-ended, unobstructed, air-confining tubes, a second set of longitudinal and transverse partitions forming with said second wall a second row of aligned, open-ended, unobstructed, airconfining tubes, one of said rows being spaced closely adjacent the other of said rows, means in the space between said rows in heat exchange contact with said longitudinal partitions for tempering said tubes, means forming a relatively large plenum chamber spaced from said tubes at one end thereof and extending substantially the length of said unit, a relatively small conduit for connecting said chamber to said source, and a pair of rows of nozzles extending from said chamber towards said end of said tubes, said nozzles terminating substantially at the adjacent ends of said tubes, said nozzles being equal in number to said tubes and being substantially smaller at their tips than the interiors of said tubes, each of said nozzles being aligned with one only of said tubes and being arranged to discharge primary air from said chamber directly into one only of said tubes and to cause induction of secondary air into said one tube for mixture wit-h the primary air discharged into said one tube.

2. A relatively long, relatively narrow, air tempering and distributing unit for connection to a central source of conditioned .air which supplies primary air at a high velocity to said unit, comprising means forming a relatively large plenum chamber extending substantially the length o-f said unit, a relatively small conduit for connecting said chamber to said source, a first row of aligned, unobstructed, open-ended air-confining tubes, a second row of aligned, unobstructed, open-ended, airconning tubes spaced from and closely adjacent said first row, said rows extending lengthwise of said unit in parallel relationship, said rows at one end being spaced from said chamber, rows of nozzles extending from said chamber substantially to the adjacent ends of said tubes, each of said nozzles being aligned with and discharging primary air from said chamberinto one only of said tubes, the exteriors of the tips of said nozzles at said tube ends being substantially smaller than the interiors of said tubes at said one end, said nozzles discharging primary air from said chamber directly into said tubes and inducing the flow of secondary air around their tips into said tubes, said tubes each having a hydraulic dialneter not in excess of millimeters, the length of each tube being in excess of five times the hydraulic diameter thereof, and the sum of the cross-sectional areas of the tips of the nozzles being less than one-fifth of the sum of the cross-sectional areas of the tubes, and means in said space between said rows in heat exchange Contact with said tubes for tempering said tubes.

References Cited in the file of this patent UNITED STATES PATENTS 1,790,535 Coe Ian. 27, 1931 1,914,200 Davis et al. lune 13, 1933 2,122,168 Woolley June 28, 1938 2,651,506 Lehmann Sept. 8, 1953 FOREIGN PATENTS 813,513 France lune 3, 1937

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