US3769810A

US3769810A - Field installed low ambient damper for outdoor rooftop condenser installation

Info

Publication number: US3769810A
Application number: US00284001A
Authority: US
Inventors: R Swartwout
Original assignee: Dunham Bush Inc
Current assignee: Dunham Bush Inc
Priority date: 1972-08-28
Filing date: 1972-08-28
Publication date: 1973-11-06
Anticipated expiration: 1990-11-06

Abstract

A temperature responsive, adjustable louver damper box overlies the hot air discharge opening in the top of a standard rectangular condenser housing exposed to outside air with the forward portion of the box overhanging the front of the condenser housing. Louvers in closed position recirculate at least a part of the hot condenser discharge air through the box for discharge in front of the intake opening of the condenser housing.

Description

iliiited States Patent CONDENSER INSTALLATION [75] Inventor: Richard J. Swartwout, Penn Laird,

[73] Assignee: Dunham-Bush, Incorporated,

Harrisonburg, Va.

[22] Filed: Aug. 28, 1972 [21] Appl. No.: 284,001

[52] US. Cl. 62/183, 62/507 [51] llnt. Cl. F251 39/04 [58] Field of Search 62/183, 507

[56] References Cited UNlTED STATES PATENTS 3,004,402 10/1961 Dart 62/183 Swartvvout Nov. 6, 1973 FIELD INSTALLED LOW AMBIENT 3,466,889 9/1969 Fristoe 4. 62/507 DAMPER FOR OUTDOOR ROOFTOP 3,584,466 6/1971 Kaufman et a]. 62/183 Primary Examiner-Meyer Perlin Att0rney-Richard C. Sughrue et al.

[57] ABSTRACT A temperature responsive, adjustable louver damper box overlies the hot air discharge opening in the top of a standard rectangular condenser housing exposed to outside air with the forward portion of the box overhanging the front of the condenser housing. Louvers in closed position recirculate at least a part of the hot condenser discharge air through the box for discharge in front of the intake opening of the condenser housing.

7 Claims, 3 Drawing Figures FIELD INSTALLED LOW AMBIENT DAMPER FOR OUTDOOR ROOF TOP CONDENSER INSTALLATION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to refrigeration systems, and more particularly to an arrangement for controlling the refrigerant head pressure at low ambient temperatures in a system where the condenser is normally exposed to the outside air.

2. Description of the Prior Art Condenser coils forming portions of relatively large refrigeration systems are conventionally contained by relatively large rectangular housings mounted on a rooftop or in other positions of normal exposure to outside air. Such housings are provided with an intake opening within the housing permitting entry of relatively cool ambient air for passage over the condenser coil and for discharge through a related opening downstream of the condenser, under forced air flow created by electric motor powered-blowers or the like.

In order to maintain the temperature of the air flowing across the condenser coil within a predetermined range or above a predetermined mimimum and in order to obtain maximum efficiency in operation of the refrigeration circuit, it is conventional to employ internally of the housing, sets of damper blades or louvers in order to recirculate some of the already heated air through the condenser by mixing it with the incoming ambient, at times when the ambient temperature is relatively low. Such recirculation systems as set forth in U. S. Pat. No. 3,148,514, are characterized by a plurality of sets of louvers with multiple temperature controls associated therewith to the control of positions of the various louver blades.

In the space conditioning field, particularly in large industrial and commercial buildings requiring air con ditioning or commercial refrigeration, a unit conditioner, in terms of the equipment positioned exterior of the building and exposed to the outside air, is constituted by a rectangular condenser housing in which a vertical sidewall carries a large opening which acts as the cooling air inlet to the condenser, while a second opening is provided within the'top of and downstream of the condenser coil and the blower which permits the heated air, assisted by convection, to escape upwardly and away from the unit.

It is, therefore, a principal object of this invention to provide at least one assembly constituted by a single set of louver blades which may be readily coupled to an existing conventional condenser housing of this type providing a low cost, simplified means for regulating recirculation of heated condenser discharge air past the condenser coil, so that air temperature can be maintained at or above a predetermined minimum regardless of most ambient conditions.

SUMMARY OF THE INVENTION The present invention is particularly directed to at least one damper box which overlies the condenser housing and is fluid coupled to the hot air discharge opening within the condenser housing. The damper box has a portion which extends forwardly beyond the front of the condenser housing and overhangs the same. A first discharge opening in the top of the box permits complete discharge of the heated condenser air in normal fashion. A set of louvers are positioned within the box intermediate of top and bottom aligned horizontal openings. A second bottom opening, in the overhang portion, controls recirculation of a portion of the heated air from the discharge side of the condenser to the intake side of the condenser.

A damper motor may be fixed to the damper box for rotating the louvers in unison between a horizontal position tending to recirculate the condenser discharge air or a generally vertical position in which the heated condenser discharge air passes directly through the top of the damper box. A thermostat mounted exterior of the auxiliary housing is operatively coupled to the damper motor for controlling the position of the louvers. Linkage connecting the damper motor to the louvers includes adjusting means permitting the percentage of recirculated air to be varied. For a large condenser unit having multiple condenser coils in side-byside fashion, a plurality of damper boxes may be provided in tandem operated from a single damper motor with shafts extending between aligned louvers of respective boxes and wherein one louver set acts as a master unit and the second acts as a slave unit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a tandem damper box arrangement used in conjunction with an outdoor condenser and forming a preferred embodiment of the present invention.

FIG. 2 is an end elevational view of the arrangement illustrated in FIG. 1.

FIG. 3 is a sectional view of the master damper box of FIG. 1 taken about line 3-3. Y 1

DESCRIPTION OF THE PREFERRED EMBODIMENT The motorized damper box of the present invention has application to space conditioning systems for re frigeration and air conditioning use, in which the condenser coils are housed in position for normal exposure 'to the outside air. Referring to the drawings, the condenser to which the invention has application, is constituted by a rectangular housing or casing 10 comprising vertical sidewalls l2 and a front wall 14 and having a top or cover 16 provided with one or more elongated rectangular openings such as opening 18, FIG. 3, which is positioned to the rear of the condenser coil 20. In this respect, as indicated in FIG. 3, the front wall 14 is provided with at least one large rectangular opening 22, and immediately behind this opening and within an area defined by the front wall 14 and a flange 24 is located in vertical orientation, the condenser coil 20, through which the air for cooling of the coil passes, as indicated by arrows 26. The coil 20 is cooled by forced air under operation of a blower (not shown) which lies internally of the condenser housing 10 and downstream of condenser coil 20. The opening 18 in addition to being formed by the flange 24, is further defined by a vertical partition 28 which causes along with convection currents, the heated condenser air to rise and pass through discharge opening 18 within cover 16. Normally, the opening 18 within the top or cover 16 of the condenser housing or casing 10 is provided with a grill (not shown) inserted within the same and permitting air to pass through openings within the grill virtually unimpeded. I

The present invention is directed specifically to the employment of one or more motorized damper boxes which may be fixedly mounted on top of the condenser housing, overlying the condenser air discharge opening and incorporating means for recirculating the heated condenser air to the intake opening at the front of the condenser housing for raising the ambient available to the condenser. In this respect, as illustrated in FIG. 1, there is provided in tandem, a first, master damper box 30 fixedly mounted to the cover or top 16 of condenser housing and having mechanically coupled thereto a second slave damper box 32 of generally identical construction with both damper boxes being operated by a single damper drive motor 34 fixed to the rear of damper box 30. Like elements with both boxes are given the same numerical designations. Essentially, each damper box comprises a rectangular housing defined by paired

sidewalls

34 and 36 connected together by a front wall 38 and a rear wall 40 with the bottom of a damper box being essentially open and with the top being provided with a short cover section or top 41 at the front thereof and extending rearwardly at least to the extent of the overhang of the damper box relative to the front wall 14 of the condenser housing 10. Each damper box, therefore, is provided with a discharge opening 42 within the top rear half of the damper box and a vertically aligned rear bottom opening 44, which overlies the discharge opening 18 of the condenser housing 10. A front bottom opening 45 of

boxes

30 and 32 also overlies the air intake area immediately in front of the intake opening 22 of the condenser housing 10. The rear wall 40 of each damper box is provided with a right angle flange 46 permitting the damper box to be fixedly attached to the cover 16 of the condenser housing 10 in a longitudinal direction along the rear edge of condenser discharge opening 18 through the use of rivets, screws, bolts, etc. (not shown). Further, extending between the

sidewalls

34 and 36 is a depending, L- shaped mounting bar 48 with its vertical portion conforming to a flange 24 defining the front edge of the same condenser air discharge opening 18. Bar 48 is fixedly coupled to the cover 16 adjacent the front edge of opening 18 by similar coupling means such as bolts,

screws or the like. The bar 48 acts in conjunction with partition 50 which extends downwardly from the inner end of cover 41, and which may be welded or otherwise attached thereto, to define a relatively narrow horizontal air passage 52 which permits the selective flow of at least a portion of the heated condenser air into a chamber 54 defined by the front wall 38, cover 41 and the partition 50 of each

damper box

30 and 32. The deflected, heated air escapes from chamber 54 in a downward direction through opening 45 in the bottom of the damper box which overlies the intake area of the condenser, specifically mixing with the incoming ambient air and raising the temperature of the same prior to passing through condenser coil 20.

The selective recirculation of the heated condenser air is achieved through the use of a plurality of pivotal damper blades or louvers 56 formed of stamped sheet metal or the like and mounted for pivoting about individual horizontally aligned pivot axes, which are also in line with the bottom end of vertical partition 50, each axis defined by respective mounting shafts 58 at both ends of the blades. Aligned openings are provided within the

sidewalls

34 and 36 with the shafts 58 protruding therethrough and being fixedly coupled to respective ends of the damper blades or louvers by straps 60. In this respect, each blade is configured such that the outer ends terminate in angularly bent edges 62, while the center of each blade is grooved as at 64 permitting the shafts 58 to be partially received by the grooves 64 and held in position by the straps 60 which are bent to form a central recess as at 66. The shafts which are inserted through the holes of slightly greater diameter within

sidewalls

34 and 36 of the damper box, project within the openings formed by the straps 60 and the grooved blades 56. While the blades can be pivoted to fully closed position in which the bent edges 62 abut, they are normally held in a partially closed position to deflect a portion of the heated condenser air for recirculation as shown in FIG. 3. In the fully open position, practically all the condenser air passes by convection and forced flow due to blower operation, vertically upwards for discharge through the opening 42 within the top of each damper box.

In order to pivot the blades 56 in unison to effect recirculation as desired, the ends of shafts 58 which protrude from the left hand sidewall 34 of the damper box 30, for instance, are each provided with a damper crank arm 68, the inner end of each crank arm being coupled to its shaft by screw 70. Each damper crank arm 68 carries, at its outer end, a pin 72 projecting outwardly therefrom and generally parallel to the louver mounting shafts 58, the pin 72 being bored and being positioned on the damper arm such that a common connecting rod 74 passes therethrough and acts to mechanically interlock all three damper crank arms 68 associated with louvers or blades 56 for both the master damper box 30 and the slave damper box 32.

Further, one of the damper crank arms 68 in this case, the right hand crank arm, FIG. 2, is further provided with an elongated slot 76 which slidably carries, adjustably positioned pin 78 forming a lockable pivot point for a damper arm drive rod 80 which acts as the link between the drive motor crank arm 82 and the interlocked louvers or blades 56. The damper motor 34 constitutes a low power D. C. or A. C. drive motor whose output or drive shaft 84 protrudes through a mounting bracket 86 which fixes the motor 34 to the rear wall 40 of the master damper box 30. The drive shaft 84 carries a motor crank arm 82 which is quite similar in configuration and construction to right hand damper crank arm 68 carrying the adjustment slot 76. The motor crank arm 82 carries a slot 87 which supports a longitudinally adjustable and lockable pivot pin 88 which receives one end of the connecting link or drive rod 80, the other end of which is received by pivot pin 78 associated with the right hand damper crank arm 68. The damper drive motor 34 is powered from electrical source (not shown) under control of a thermostat 90 which in this case is fixed to the rear wall 40 of the master damper box 30. A bracket 92 supports the thermostat bulb 94 in a position such that it may readily sense the outside air temperature unaffected by the heated air passing through the master damper box, and lead 96 passing through the rear wall 40 by means of bushing 98 permits control of an electrical circuit which includes the thermostat bulb 94 and the damper drive motor 34.

In the illustrated environment of use, the condenser housing 10 may, in fact, comprise one portion of a combination heating-cooling unit of which the refrigeration system components may occupy the right hand portion of the condenser housing 10, as seen from the front, and in which case, theopenings 18 within the top or cover 16 of the condenser housing extend longitudinally parallel to the front wall 14 just rearwardly of the condenser coil 20 and over a distance considerably in excess of the width of the master damper box 30. In this case, a pair of side-by-side condenser coils 20 are carried internally of housing and in order to obtain the desired hot condenser air recirculation to the intake openings 22 within the front wall 14 of condenser housing 10 for both condensers, it is necessary to provide a plurality of damper boxes in series, that is, in tandem. In this respect, the shafts 58 which are carried by wall 36 of the master damper box extend well beyond the outside of the damper box 30 and in fact pass through wall 34 of the slave damper box 32and are fixed in the identical manner, at their opposite ends, to the louvers or damper blades 56 of the slave damper box 32. In all other respects, the slave damper box 32 is identical in construction to that of the master damper box 30 with the exception that there is no drive motor or thermostat for controlling the slave damper box 32 independently of the master damper box 30. Pivoting or shifting the position of all damper blades 56emanates from the single drive motor 34 carried by the master damper box 30. Further, while the slave damper box 32 is illustrated as being longitudinally spaced from the master damper box, in fact the two boxes may be placed essentially side-by-side depending only in the position of openings 18 within the-housing cover 16, and thus maximum efficiency is achieved in recirculating a portion of the heated condensed air to the inlet side of the condenser for mixing with the fresh outside air. Further, while the master damper box 30 and the slave damper box 32 are illustrated as being spaced longitudinally in FIG. 1, this is because in the illustrated application, for an eight ton refrigeration unit, there is positioned within housing 10' a pair of longitudinally aligned in-line condenser coils 20 with each condenser being provided with a fan or blower for forced movement of the air through the condenser and for discharge through respective longitudinally spaced openings, in this case, within the top or cover 16 of the condenser housing 10. Alternatively, the damper box may comprise a single unit which extends longitudinally across both openings 18 within the larger ton units and in which case, the forward end of the damper box overlies air intake openings to both condenser coils.

During operation, and assuming that ambient conditions are such that the outsideair temperature is in excess of 50 F., the louvers 56 for both the master damper box 30 and the slave damper box 32 will be positioned as essentially shown in FIGS. 1 and 2, that is, in the fully open position, whereby all of the condenser air escapes upwardly through the openings 42 within the top of both damper boxes and without any heated air being recirculated to the front of the condenser housing 10. With the control system controlling the damper drive motor 34set to operate at 50 F., when the temperature drops below 50 F a circuit is completed by the thermostat bulb 94, such that the damper drive motor 34 is energized. This causes the damper blades or louvers 56 to move from the fully open position shown towards closed position as indicated in FIG. 3, and the condenser discharge air emanating from the condenser housing 10 through the top openings 18, is forcibly directed into chamber 54 and escapes through the front at bottom opening 45 within the bottom of each damper box for mixing with the cold outside air and raises the ambient by approximately 30 over the free ambient. This results in an increase in condensing pressure of approximately psi, and as a result the refrigeration unit incorporating the condenser coils 20 may operate down to 20 F.

Where the present invention has application to a combination heating and cooling unit in order to prevent the dampers from closing during the heating mode, an electrical interlock is provided by means of a relay (not shown) wired in parallel with the cooling relay (not shown). Further to permit cold starts a timer (not shown) is employed which delays operation of the damper motor 34 by approximately five minutes to allow the suction to build up to satisfactory levels.

From the above, it is readily apparent that one or more damper boxes as a complete subassembly may be readily incorporated or attached to the top of an existing condenser housing by the simple expedient of removing the condenser discharge grill overlying an opening such as the top opening 18 in condenser 10 and securing the damper to the top of the condenser housing by means of screws or bolts and by using the same holes as mounted the removed discharge grill. Where needed, a secondary identically constructed damper box may be employed as a slave damper, in which by the simple expedient of employing relatively long shafts as a means for interconnecting respective blades or louvers of the slave damper box 32 to the respective louvers within the master damper box 30, the drive motor of the master damper box drives both sets of louvers. To prevent a continued build up in the condenser discharge air temperature, the dampers are so constructed that they do not fully close but preferably move to a partially inclined position from the vertical as illustrated in FIG. 3 permitting a portion of the hot condenser air to escape while taking in a continuous supply of fresh air.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is: 1. In a condenser forming a component of a refrigerating system and normally being exposed to outside air and including a housing enclosing the condenser coil and having a first, vertical opening defining a condenser air intake facing the condenser coil, and a horizontal opening within the top of thehousing defining a warm air discharge opening downstream of said coil, the improvement comprising:

at least one damper box supported on top of said condenser housing and having aligned intake and discharge openings overlying said condenser housing warm air discharge opening,

said damper box further including a frontal portion overhanging the front of said condenser housing and including a discharge opening within the bottom of the same beyond the front wall of said condenser housing, and

a horizontal array of selectively adjustable damper blades within said damper box positioned intermediate the aligned inlet and discharge openings of said damper box,

whereby, upon closure of said damper blades, at least a portion of said hot condenser discharge air is deflected towards said frontal portion of said damper box for discharge through the bottom opening within the same and recirculation, with the incoming fresh air passing through said condenser housing intake opening.

2. The condenser as claimed in claim 1, wherein said damper box comprises a rectangular housing including imperforate side, front and rear walls, the bottom of said damper box being essentially open and said top of said box also being open at the rear but including a cover overlying the frontal overhang portion to prevent discharge of the deflected hot condenser discharge air except through that portion of the opening within the bottom of said box which extends beyond the front wall of said condenser housing.

3. The condenser as claimed in claim 2, further comprising a vertical partition extending across the damper box from one sidewall to the other and downwardly from the inner edge of said cover and terminating short of the bottom of said damper box, and wherein said plurality of damper blades are pivotably mounted on respective axes which are coplanar with the bottom edge of said vertical partition.

4. The condenser as claimed in claim 3, wherein said blades are pivoted by shafts extending through said damper box sidewalls and fixed thereto, and wherein crank arms are fixed to the ends of said shafts and rotatable therewith, means commonly connect said damper crank arms for respective blades together for pivoting in unison, a damper drive motor is fixed to said damper box with a drive shaft extending outwardly therefrom and generally parallel with said damper mounting pivot shafts, a motor crank arm is fixed to the said motor drive shaft, and adjustable linkage interconnects said motor crank arm to one of said damper crank arms.

5. The condenser as claimed in claim 4, wherein at least one of said damper crank arms is provided with an elongated slot along a portion of the length thereof, said motor crank arm further comprising a similar elongated slot, lock-pivot means are carried by said slotsfor adjustable positioning along the length of the same, and a connecting rod interconnects said lock-pivot means for said damper crank arm and said motor crank arm, respectively.

6. The condenser as claimed in claim 5, wherein said condenser comprises two side-by-side condenser coils within said condenser housing and adjacent the front wall of the same, the top of said housing comprises horizontal warm air discharge openings for respective coils, downstream of the coils and rearwardly of the front wall of said condenser housing, said damper boxes comprise two in number constituting a longitudinal array fixed to the top of said condenser housing, one of said damper boxes constituting a master damper box and carrying said damper drive motor, said other damper box constituting a slave damper box, and means for mechanically intercoupling the damper blades of said master damper box to those of said slave damper box for effecting blade rotation in unison under control of said master damper box drive motor.

7. The condenser as claimed in claim 6, wherein aligned openings are provided within respective adjacent sidewalls of the master damper box and the slave damper box, wherein said mechanical intercoupling means comprise damper blade mounting shafts extending through aligned openings within said respective sidewalls and means fixedly coupling respective ends of said shafts to corresponding damper blades within said boxes.

Claims

1. In a condenser forming a component of a refrigerating system and normally being exposed to outside air and including a housing enclosing the condenser coil and having a first, vertical opening defining a condenser air intake facing the condenser coil, and a horizontal opening within the top of the housing defining a warm air discharge opening downstream of said coil, the improvement comprising: at least one damper box supported on top of said condenser housing and having aligned intake and discharge openings overlying said condenser housing warm air discharge opening, said damper box further including a frontal portion overhanging the front of said condenser housing and including a discharge opening within the bottom of the same beyond the front wall of said condenser housing, and a horizontal array of selectively adjustable damper blades within said damper box positioned intermediate the aligned inlet and discharge openings of said damper box, whereby, upon closure of said damper blades, at least a portion of said hot condenser discharge air is deflected towards said frontal portion of said damper box for discharge through the bottom opening within the same and recirculation, with the incoming fresh air passing through said condenser housing intake opening.

5. The condenser as claimed in claim 4, wherein at least one of said damper crank arms is provided with an elongated slot along a portion of the length thereof, said motor crank arm further comprising a similar elongated slot, lock-pivot means are carried by said slots for adjustable positioning along the length of the same, and a connecting rod interconnects said lock-pivot means for said damper crank arm and said motor crank arm, respectively.