US 3324782 A
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June 13, 1967 J. w. NoRRxs ET AL AIR TREAT ING APPARATUS 5 Sheets-Sheet l Filed Dec. 28, 1964 June 13, 1967 J. W, Nogms ET AL AIR TREATING APPARATUS 5 Sheets-Sheet 2 Filed Dec. 28, 1964 A ...MIIIVHMHMIIHMMM .Wim IJLW June 13, i957 W Npgmg ET AL AIR TREATING APPARATUS 5 Sheeis-Sheet 3 Filed Dec. 28, 1964 June 13, i967 J. w. NoRRas ET AL AIR TREATING APPARATUS 5 SheetS-Sheet Filed Dec. 28, 1964 June 13, 1967 J. w, NQRRlS ET AL 3,324,782
AIR TREAT I NG APPARATUS 5 Sheets-Sheet 5 Filed Deo. 28, 1964 E fm2/anfora' United States Patent O 3,324,782 AIR TREATING APPARATUS John W. Norris, Marshalltown, and Wayne F. Sieverdmg,
Union Grove Lake, Iowa, assignors to Lennox Industries Inc., a corporation of Iowa Fiied Dec. 28, 1964, Ser. No. 421,427 6 Cim'ms. (Cl. 98--33) 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 1n 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 ltreating units fail to provide an adequate solution. The particular difficulties 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 eiciently fulfilled 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 xtures 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 4the 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 roorn atmosphere than do the older and larger children of the upper-class grades. There are also variations from class to class in the amount of light-ing required dependent upon the reading activities of the various vgrade 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 room is often supplemented by direct sunlight striking against the building as the daylight hours progress. In some instances, one or several Vof 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 3,324,782 Patented June 13, 1967 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 outdoop' weather conditions.
Gutdoor 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 inside 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 vone 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 treating -unit 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 Within such school.
A further object of the present invention is to provide an integrated air conditioning or air treating system incorporating 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.
Yet another object of the present invention is to provide an air treating assembly including an exhaust and outdoor air intake unit having a powered exhaust fan to assure the use of one-hundred-percent outdoor air when needed, such unit including control air dampers, outside air dampers and exhaust air dampers, all interconnected and actuated by a modulating damper motor.
A further object of this invention is to provide a novel base assembly for facilitating the mounting of a factory assembled integrated air conditioning unit on the roof of a building.
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 Iout 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 air treating assembly of the present invention;
FIGURE 2 is a vertical cross-sectional View of the air 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;
FIGURE 6 is a perspective View of the baffle employed in the mixing damper assembly of the present invention;
FIGURE 7 is a perspective View of the base frame for supporting the air treating assembly of the present invention on a roof top in one application of the present invention;
FIGURE 8 is a detail cross-sectional view of a side of the base; and
FIGURE 9 is a detail view on an enlarged scale of the installation of the air treating assembly of the present invention on a roof top.
Referring now to FIGURES 1, 2 and 3, there is illustrated the air treating assembly of the present invention. The air treating assembly 10 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 10; 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 fire 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 28 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 communiacte 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 one-hundred-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.
Af'ixed 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 one-hundred percent of the air handled by the unit can go through any one of the three damper sets. This allows onehundred-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 46 draw air through filter 50. Filter 50, which may be made from a highly efficient 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 baffles 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 18 or to the cooler 19 for suitable conditioning.
The heater 18 may be a gas-fired furnace or' an electric resistance-type unit.
The cooling coil or evaporator 19 is opeartively 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 18 and evaporator 19, respectively, flows into the mixing damper assembly 20 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 baffle 6l) and uniformly spread across the width of the compartment defined below baille 60 as indicated by the dotted arrow lines in FIGURE 3. The cool air from coil 19 is guided above baffle 60 and uniformly spread across the width of the compartment defined above bafe 60 as indicated by the solid larrow lines in FIGURE 3.
Provided in the entrance to each of the compartments 64-73 defined at the rear of unit 20 by upright divider plate 64a-72a are damper means 75 for regulating the quantity of air entering each compartment. As seen in FIGURE 5, each damper means 75 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 motor 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 FIGURE 5.
Referring to FIGURE 6, there is better seen the construction of baffle 60. The bafiie includes a plate 79 having a sharply upwardly inclined portion 80 having a flange 81 at the front thereof generally in alignment with the heater 18 and a slightly upwardly inclined portion 82 havling a flange 83 at the front thereof generally in alignment with the coil 19. The inner edges of wall portions 80 and 82 are connected by a vertical divider wa11v84.
The flow directing baflie 60 guides the air discharged from the heater 18 and coil 19 into the mixing damper unit 20 in flow paths that are separated from one 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 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 air temperature.
On the heating side, the ductstat is compensated in accordance with outside air temperature in a predetermined manner, 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 55 F., the compressors 23 are shut of 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 and 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 efficient 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 re. quiring heating. At temperatures above the selected ternperature condition, the dampers will be open to one-hundred-percent outside air until attainment of a higher predetermined temperature, about 67 F., at which point the darnpers are returned to the minimum position for 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 damper 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.
Considering FIGURES 7, 8 and 9, there is shown a base or frame assembly 84 for facilitating mounting the air treating system in place for use on the roof of a school or like building. The frame is comprised of heavy metal extruded peripheral members 86a and cross members 86b, with panel members 86e closing the spaces between adjacent frame members. Aluminum may be used to form the members 86a and 86h. Insulation 87 is bonded to the inside of the frame members making up all six sides of the base (top, bottom, and four sides). Such insulation may be a polyurethane foam, which adds structural rigidity to the frame.
The frame 84 is adapted to be positioned directly on a roof top or on an auxiliary mounting frame such that opening 88 therein communicates with a return air opening in the roof and opening 89 communicates with an opening in the roof communicating with the zones in the building to be conditioned. Frame 84 is sealingly engaged with the bottom of device 10 and has sufhcient strength and rigidity to support the air treating apparatus 10 at any four points under the perimeter frame.
The frame or base 84 is supported in a typical installation (FIGURE 9) on an air seal 90 which rests on an annular support Wall defined by roof curbing 91, rigid insulation 92, and counter flashing 93 provided about the periphery of the frame `84. The air seal 90, which may be formed from vinyl sponge, lies beneath the periphery of frame 84 and prevents entry of air between the frame 84 and the adjacent portions of the roof. The seal also accommodates minor variations in flatness between the frame and the roof and thus functions as a water seal. Further, the resilient seal 90 forms a vibration elimination seal for isolating any high frequency vibration that has not been dampened by the mounting for the blowers 46.
The construction shown assures an accurate fit of the air treating apparatus to the roof opening. Further, the annular support wall cooperates with the roof and frame 84 to define a return air collection chamber. Use of frame 84 will allow placement of the air treating apparatus 10 on the annular support wall at any period before or after the roofing or insulation is in place. This frame also permits elimination of roofing underneath the apparatus 10 and thus provides easy access to the bottom of the apparatus 1t) for the application of wiring conduit for both the power and control wiring. Thus, the unit 10 will not have to be moved or removed in the event that any of the built up roofing must be repaired or replaced.
The air treating system of the present invention is ideally suited for use in meeting the variable and complex 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-hundred-percent outside air when needed. The dampers can be adjusted to continuously introduce the amout of outside air required for proper freshening and odor removal during all periods of occupancy. During nonoccupied periods, one-hundredpercent 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 18 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 iiexibility.
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.
1. An air treating unit comprising a housing having an outside air inlet in one side Wall thereof, a return air inlet in the bottom thereof, an exhaust air outlet in another wall thereof, and first and second air outlets in a common side wall thereof, a transverse wall in said housing disposed between said first and second air outlets for directing the outside air through said housing in a path separate from said return air, first damper means for regulating air iiow through said first air outlet, second damper means for regulating outside air flow through said second air outlet, third damper means for regulating the exhaust of air from said housing through said exhaust air outlet, said exhaust air outlet communicating with said return air inlet, said Y first, second, and third damper means being interconnected for simultaneous operation to permit predetermined quantities of outside air and return air to pass through said housing and to permit a predetermined quantity of return air to be exhausted from said housing, and control means including motor means for actuating the damper means responsive to predetermined conditions.
2.- An air treating unit as in claim 1 including fan means in the housing adjacent said exhaust air outlet for assuring the exhaust of air from said housing.
3. An air treating unit as in claim 2 wherein said fan Imeans are actuated when said second damper means is opened a predetermined amount, said third damper being modulated to harmonize the amount of exhaust air with the amount of outside air passing through the housing.
4. An air treating unit as in claim 2 wherein each damper means is sized so that all of the air handled by the unit can pass through any one damper means, thus permitting one-hundred-percent recirculation of air or onehundred-percent outside air with assured exhaust to make it possible, or any mixture thereof.
5. A multi-damper assembly for regulating the quantity of outdoor air supplied to an integrated air conditioning unit, the quantity of room air returned to said air conditioning unit, and the quantity of air exhausted from said air conditioning unit, said multi-damper assembly comprising a housing having a return air inlet for receiving room air, an outdoor air inlet for receiving outdoor air, a return air outlet, an outdoor air outlet, and bottom wall of said housing and said exhaust outlet being an exhaust outlet, said return air inlet being disposed in a disposed in an upright wall of said housing opposite from said outside air inlet, said return air outletand said outdoor air outlet being disposed in side-by-side relation in a common upright wall of the housing, first damper means for controlling the quantity of air exhausted from said housing through said return air outlet, second damper means for controlling the quantity of outside air passing through said outside air outlet, third damper means for controlling the quantity of return air exhausted from said housing, a single damper control mechanism for srnultaneously actuating said first, second, and third damper means in response to a predetermined condition to modulate the positions of the rst, second, and third damper means to maintain a predetermined passage of air through said housing, thereby providing proper air freshening and ventilation, and fan means for selectively exhausting all of the return air entering said housing disposed in the hous-rV ing.
6. An air treating unit as in claim 2 wherein the housing includes a wall spaced from said other wall, au exhaust opening formed in said spaced wall, back draft damper means provided in the exhaust air in the spaced Wall to prevent entry of outdoor air into the housing when the fan means are not operating, the fan means being disposed between the back draft damper means and the third damper means. 1
References Cited UNITED STATES PATENTS 4/1945 Jones 165-16 7/ 1956 Kreuttner 165-29