US3372870A - Air treating unit - Google Patents

Description

March 12, 1968 1. w. NoRRls ET AL AIR TREATING UNIT 4 Sheets-Sheet l Original Filed Dec. 28, 1964 JWM MarCh 12, 1958 J. W. NORRxs ET AI- 3,372,879

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4 Sheets-Sheet 5 J. W. NORRIS ET AL.

March 12, 1968 AIR TREATING UNIT Original Filed Deo. 28, 1964 MTM/M wmrhw SW @WO/w?, 4U Z www L mw\ TMF. o e n wmn n m wa m m N h 1% @y u o m EJ MH w o m Tx h uw um March 1.2,v 1968 NORRIS ET AL AIR TREATING UNIT Original Filed Dec.

4 Sheets-Sheet 4 United States Patent Olhce 3,372,870 Patented Mar. 12, 1968 3,372,870 AIR TREATING UNIT .lohn W. Norris, Marshalltown, and Wayne F. Sieverding,

Union Grove Lake, Iowa, assignors to Lennox Industries lne., a corporation of Iowa Original application Dec. 28, 1964, Ser. No. 421,427, now Patent No. 3,324,782, dated June 13, 1967. Divided and this application Feb. 20, 1967, Ser. No. 632,480

3 Claims. (Cl. 236-13) ABSTRACT F THE DISCLOSURE A mixing damper assembly including a housing having side-by-side inlets for warm air and for cool air and baille means within the housing for directing warm air in a separate path above the cool air. Dainpers are provided in the plurality of sideeby-side outlets for regulating the temperature of the air discharged through the outlets.

This is a division of application Ser. No. 421,427 led Dec. 28, 1964, now Patent No. 3,324,782.

This invention relates generally to air treating apparatus for heating, cooling and Ventilating and, more particularly, to a novel central air treating unit capable of producing accurate and instantaneous temperature control in many zones.

The conditioning of the atmosphere within schoolrooms and similar enclosures which present complex and highly variable requirements for heating, cooling and ventilating represents a difficult problem for which presently known air treating units fail to provide an adequate solution. The particular diiculties encountered in schoolroom heating, cooling and Ventilating will be discussed in detail so as to provide full background for understanding the typical requirements which are eciently fullled by the present invention. It will be understood, however, that the present invention is not limited in any way solely to schoolroom or school construction, but is fully adapted for use in other buildings where it is desired to produce accurate and instantaneous temperature control in many different zones from one central system as, for example, medical centers, motels and hotels, restaurants with private dining rooms.

Architects, contractors and air treatment engineers recognize that classrooms frequently require cooling even when the outdoor weather is extremely cold. The cooling of such rooms frequently presents a far more challenging problem than does their heating. Body heat from the persons present in the classroom, heat from the lighting tixtures and radiant heat from the sun as it strikes the walls, windows and roof, frequently produce heat gains within the room which exceed the normal transmission or heat losses from the room to the cold outdoor weather. The number of occupants in each classroom, their physical size, their bodily activities and their lighting requirements vary greatly from room to room within a schoolhouse and within each room during the course of the day. For example, small children in the lower-class grades transmit relatively lower total quantities of heat to the room atmosphere than do the older and larger children of the upperclass grades. There are also variations from class to class in the amount of lighting required dependent upon the reading activities of the various grade levels.

Such factors as recess and lengths of class periods also result in a variety of different and changing conditions of heat load within various classrooms. Substantial heat is often needed in order to effect initial warming of a Classroom during the early morning hours prior to the arrival of the students at the beginning of the school day. After the arrival of the students, the body heat load within the yroom is often supplemented by direct sunlight striking against the building as the daylight hours progress. ln. some instances, one or several of the large number of classrooms may be subjected to use during the evening hours for adult community activities and the like requiring the maintenance of proper temperature conditions within only one or a few of a large number of classrooms within a given schoolhouse. It is apparent therefore, that conditions within any given classroom may change in a matter of minutes from no heat being required to heat being required, or to cooling being required and such varying conditions within one room may be entirely different from the varying conditions and requirements of an immediately adjacent room. The maintenance of comfortable temperatures within every room is a matter of great importance and it is necessary to effect the control distribution of conditioned air regardless of the outdoor weather conditions` Outdoor air provides an economical source of relatively cool air for effecting room cooling during all weather conditions in which the outside air temperature is lower than a comfortable air temperature desired in side the room. The proper heating, cooling and ventilating system for a schoolhouse classroom is one which makes maximum use of outside air for freshening and for cooling and which can very quickly bring in enough outdoor air when needed to offset the internal heat gains within the room and keep the room temperatures from overrunning a thermostat or other control setting. Such proper distribution system, therefore, must be one that is capable of handling either heated air or cool air in a manner that will provide even and uniform distribution of air` velocity through each room or area to be treated.

The complex and highly variable requirements for heating, cooling and Ventilating of classrooms is met by the air treating system of the present invention which is capable of shifting capacity to the areas of greatest instantaneous demand so as to reduce the total installed capacity requirements.

A primary object of` the present invention is to provide an integrated central station air treatingunit for a school capable of providing for air heating, cooling and ventilating in accordance with the requirements of one or more of a plurality of zones withinsuch school.

A further object of the present invention is to provide anintegrated air conditioning or air treating system inco1^- porating a mixing damper construction for effectively blending warm air and cool air prior to distribution to one or a plurality of zones to be treated.

Further objects and advantages of this invention will become apparent as the following description proceeds, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

A preferred embodiment to the invention is shown in the accompanying drawing, in which:

FIGURE 1 is a perspective view of the central station 5 air treating assembly of the present invention;

FGURE 2 is a vertical cross-sectional view of the air 3 treating assembly constructed in accordance with the principles and features of the present invention;

FIGURE 3 is a horizontal cross-Sectional view of the air treating assembly;

FIGURE 4 is an enlarged plan view of the intake and exhaust air unit incorporated in the air treating assembly of the present invention;

FIGURE 5 is an enlarged perspective view of the mixing damper unit incorporated in the air treating assembly of the present invention; and

FIGURE 6 is a perspective view of the baffle employed in the mixing damper assembly of the present invention.

Referring now to FIGURES l, 2 and 3, there is illustrated the air treating assembly of the present invention. The air treating assembly 16 is comprised of the following major components: a condensing unit 12 which may be close coupled, as shown, or which may be located remote from the air treating assembly an exhaust and air intake assembly 14; a filter and blower assembly 16; a heating and cooling unit assembly comprising a heater 18, which may be a direct re heater for any gas or resistance coils for electric heat, and a direct expansion cooling coil 19; and a mixing damper assembly 20.

The condensing unit 12 may comprise a condensing coil 22, one or more refrigerant compressors 23 and the conventional accessory controls for connecting the condensing coil and compressor in refrigerant circuit. It is preferred that the condensing -coil be air cooled and appropriate fans 24 are provided for passing air over the coil to condense the hot vaporous refrigerant moving through the tubes within the condensing coil 22.

The exhaust and air intake assembly 14 comprises a housing 26 provided in one end wall with exhaust air dampers 2,8 and in another end wall with outdoor air intake grille 30. An opening 32 is provided in the bottom of the housing 26 for communicating with the room or area to be conditioned. Thus return air enters the air treating unit 10 through opening 32. Upright walls 34 and 35 are provided in the housing 26 at either side of the inlet opening 32. The wall member 34 is imperforate so as to separate the incoming outdoor air from the air being returned to the air treating assembly from the area or areas to be conditioned. The upright wall 35 is provided with louvers or dampers 36 so as to permit regulated passage of the return air from the area or areas being treated to the atmosphere through the exhaust air dampers 28. Dampers 37 are provided in a side wall of the housing 26 to communicate the inlet air with the blower assembly 16. Also provided in the side wall of housing 26 are dampers 38. The dampers 38, which are in communication with the outdoor air inlet dampers 30, permit the passage of outdoor air to the blower and filter unit 16.

-Dampers 28 are pivoted at the top so as to be normally closed. They function as light back-draft dampers to prevent entry of outdoor air into the exhaust and air intake unit 14 when the exhaust fan 40 is inoperative.

The dampers 28 are opened only by the pressure of exhaust fan 40, which is provided to assure the use of oneh-undred-percent outside air when needed. Fan 40 is operatively driven by motor 42. The motor and fan are supported on bracket 43 within housing 26.

Afixed to bracket 43 adjacent motor 40 is a modulating damper motor 44 for simultaneously actuating dampers 36, 37 and 38 to properly regulate the quantities of outside air, return air, and exhaust air passing through housing 26. The dampers 36, 37 and 38 are interconnected with modulating damper motor 44 by means of linkage 45 (FIGURE 4).

The dampers 36, 37 and 38 are sized so that onehundred percent of the air handled by the unit can go through any one of the three damper sets. This allows one-hundred-percent recirculation, or one-hundred-percent outside air with assured exhaust to make it possible, or any mixture thereof.

The modulating motor 44 is commanded by a combination of mixed air temperature downstream from the blowers and outside air temperature.

Regulated quantities of outside air and/or return air are drawn from housing 26 through dampers 38 and 37, respectively, by blowers 46. The blowers 46 are driven by motor 48 operatively connected to the blower by a belt and pulley drive arrangement 49. Preferably, all the moving parts of the blower assembly-namely, the blower wheels, shafting, bearings, drives and motor-are mounted in a rigid frame. The entire subassembly of moving parts is resiliently suspended in the housing or cabinet 16.

The blowers d6 draw air through filter 50. Filter 50, which may be made from a highly efcient urethane foam filter material, is detachably connected in blower and filter unit 16. The filter can be vacuum cleaned in place, if desired, and a 11S-volt convenience outlet is provided in the unit 16 for convenient connection of a tank-type domestic vacuum cleaner.

The discharge of air from blowers 46 is suitably directed by batiies 52, which are interconnected to one another by linkage 53 and are actuated by damper motor 54. Air may be directed primarily to the heater 1S or to the cooler 19 for suitable conditioning.

The heater 1S may be a gas-fired furnace or an electric resistance-type unit.

The cooling coil or evaporator 19 is operatively connected in a refrigerant circuit with the condenser 22 in the condensing unit 12. `As will be apparent to those skilled in the art, the cooling components need not be incorporated into the air treating unit 10 initially, but can easily be added at a later time by virtue of the design of the assembly 10.

The warm air and the cool air discharged from the heater 13 and evaporator 19, respectively, flows into the mixing damper assembly 2) for suitable blending of the air prior to discharge into the conduits leading to the rooms to be treated. The inlet openings to the mixing damper assembly are disposed in side-by-side relationship in one side of the housing defining assembly 20.

The warm air from heater 18 is guided below stationary bafiie 64) and uniformly spread across the width of the compartment defined below baflie 60 as indicated by the dotted arrow lines in FIGURE 3. The cool air from coil 19 is guided above batiie 60 and uniformly spread across the width of the compartment defined above baie 60 as indicated by the solid `arrow lines in FIGURE 3.

Provided in the entrance to each of the compartments 64-73 defined at the rear of unit 2t) by upright divider plates 64a-72a are damper means 75 for regulating the quantity of air entering each compartment. As seen in FIGURE 5, each damper means comprises an upper damper 76 for regulating the cool air entering a mixing compartment and a lower damper 77 for regulating the warm air entering the mixing compartment. The dampers 76 and 77 are mounted upon a common shaft 78. Rotation of the shaft will move one damper toward open position and the other damper toward closed position. Modulating damper imotor 75 is operatively connected to the shafts 78 for actuating the dampers in response to a predetermined condition.

The opening in the bottom of each compartment 64- 73 is connected with a conduit for conducting the treated air to a room. If desired, the openings may be formed in the rear wall of unit 20 rather than in the bottom. There may be as many compartments as zones to be treated. It is noted that ten compartments are shown in FIGURE 3 and eight compartments are shown in FIG- URE 5.

Referring to FIGURE 6, there is `better seen the construction of lbaffle 60. The baffle includes a plate 79 having a sharply upwardly inclined portion 86 having a flange 81 at the front thereof generally in alignment with the heater 18 and a slightly upwardly inclined portion 82 having a ange 83 at the front thereof generally in alignment with the coil 19. The inner edges of Wall portions 30 and 82 are connected by a vertical divider wall 84.

The flow directing baffle 6) guides the air discharged from the heater 18 and coil 19 into the mixing damper unit 20 in iiow paths that are separated from another. The segregated air is directed uniformly into the compartments 64-73 for proper mixing and blending within each compartment.

Control of the air temperature in the air treating unit 1t) is obtained through control elements, such as ductstats located downstream from the heater 18 and the cooling coil 19. The ductstats may use long capillary tubes to sense an average lair temperature.

On the heating side, the ductstat is compensated in accordance with outside air temperature in a predetermined rnanner, as for example, on a one-to-One basis. Assuming a one-to-one basis, as outside air temperature drops one degree, the ductstat allows one degree warmer air to be maintained on the hot side of the system. The effect of this is to modulate the hot side temperature that is continuously available to the mixing dampers.

On the cooling side, the ductstat is normally set to maintain a predetermined temperature below normal room temperature on the cold side of the system. For example, the ductstat may be set to maintain about 55 F. whenever outdoor temperature is 55 F. or above. As the outdoor temperature drops -below 55o F., the cornpressors 23 are shut off because outdoor air temperature now has adequate capacity to do all of the cooling required.

Inlet air to the blowers 46 is normally a mixture of outside air and return air when the air treating apparatus is in use land the schoolhouse is occupied. A hydraulic bulb which senses mixed air temperature from the downstream side of the blowers modulates damper motor 44 to move the dampers 36, 37 and 38 to positions to maintain a predetermined mixed air temperature. A temperature of about 60 F. has been found satisfactory for etiicient operation of the system. This provides proper air freshening and `ventilation and adequate cooling by means of the use of outside air (rather than the cooling coil) without being a burden to heating for those zones or areas requiring heating. At temperatures above the selected temperature condition, the dampers will be open to onehundred-percent outside air until attainment of higher predetermined temperature, about 67c F., at which point the dampers are returned to the minimum position yfor required ventilation.

At outside temperatures below 60 F., the dampers 36, 37 and 38 will modulate to a position of outside and return air that provides -a mixed air temperature of 60 F.

Control of the temperature in a room or Zone is obtained by a room thermostat which commands the threeposition ldamper motor 75 which actuates the mixing damper or dampers feeding to that zone. It will be understood that there may be one damper motor for each upper and lower damper or that one damper motor may control a plurality of upper and lower dampers.

The air treating system of the present invention is ideally suited for use in meeting the variable land cornplex heating and cooling requirements in multizone buildings, as for example, schoolhouses, medical centers, and motels. The complete heavily-insulated outdoor package is assembled, wired, and piped at the factory, thus requiring minimum installation costs on the job site. Though the air treating system may be conveniently mounted on a roof top, it can easily be installed on a slab adjacent to the building or even installed in an equipment room, if required by the building design.

Integrated within the air treating assembly are air dampers that control return air, outside air, and exhaust air, all the dampers being interconnected and actuated by an electric modulating damper motor. A powered exhaust fan is provided to assure the use of one-hundredpercent outside air when needed. The dampers can be adjusted to continuously introduce the amount of outside air required for proper freshening and odor removal during all periods of occupancy. During nonroccupied periods, one-hundred-percent recirculated air may be used for economy.

A mixing damper assembly is provided in the air treating unit for supplying a plurality of separate zones with desired conditioned air. The mixing damper assembly is capable of shifting capacity to areas of greatest instantaneous demand, thereby reducing the total installed capacity. For certain applications, for example, when the system is installed for dual duct distribution the mixing damper assembly is omitted and the discharge from the heater i8 and the direct expansion coil 19 communicates with a warm air duct and a cool air duct, respectively, for transmission to a mixing box adjacent to the area to be treated. Thus, it is seen that the air treating system of the present invention provides for great design flexibility.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the `art that various changes and modifications may be made therein Without departing from the invention and, therefore, it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

We claim:

1. In a mixing damper assembly for an air treating unit, the combination of a tubular housing having a Warm air inlet and a cool air inlet in side-by-side relationship in one side thereof, a stationary baffle plate disposed transversely in said housing intermediate the top and bottom walls thereof for directing the Warm air and the cool air entering through said inlets transversely from the Warm air inlet and cool air inlet, respectively, .in separate iiow paths, means defining a plurality of compartments in said housing, damper means in the entrances to the compartments for controlling the yquantity of warm air and cool air introduced into the compartments, and the control lmeans for regulating the damper means in response to predetermined temperature requirements.

2. An air treating unit for continuously recirculating room air and conditioning the iiow thereof with warm air, and cool air comprising a mixing damper assembly including a housing having a Warm air inlet and a cool air inlet defined in one end wall thereof, said inlets being spaced from another in side-by-side relationship, there being a plurality of outlet openings in said housing remote from the inlets, upright divider plate spaced from one another for defining a plurality of mixing compartments within said housing, damper means supported in the entrance to each compartment for selectively regulating the flow of warm air and cool air into each compartment, said damper means comprising an upper damper and a lower damper affixed to a common shaft, and a baie plate in said housing for directing the Warm air from the warm air inlet transversely of the housing to each compartment in a lower flow path and for directing the cool air from the cool air inlet transversely of the housing to each compartment in an upper iiow path separate from said lower flow path, and control means for actuating said damper means in response to a predetermined condition to regulate the temperature of the air discharged from each compartment to a point of use.

3. A mixing damper assembly for use in an integrated roof-supported air conditioning unit comprising a housing having a Warm air inlet and a cool air inlet detined in one end Wall thereof, said inlets being spaced from one another in side-by-side relationship, there being a plurality of outlet openings in the bottom of the housing adjacent the other end wall, spaced divider plate means in said housing for dening a compartment adjacent each outlet opening, damper means Supported for movement about upright axes extending in spaced relationship transversely of the housing for regulating the flow into each compart- 3,372,870 7 ment, said damper means `comprising an upper damper eect a desired controlled mixing of the two supplies, and a lower damper affixed to a ,Common Shaft, Wan and control means for actuating the damper means.

gndlfg genfugfgnsrsylm.Sei oufgg bell References @ses eens wamalrme in sal c o alrme s1 Wa T means directing Warm air transversely of the housing to 5 UNITED STATES PATENTS each compartment and directing the cool air transversely 1 Q15204 1/1912 Muffyv 236-13 of said housing to each compartment in a path separate I/[cd 2362361-3-1; from and generally above said Warm air, whereby the Oms e a cool air and Warm air supplies are transferred from side- 10 EDWARD 1 MICHAEL Pfl-mary Examiner. by-side relationship to under and over relationship to

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