Self-contained flush-mount bulkhead air conditioning unit with novel evaporator/blower assembly housing

An air conditioning unit having a flush-mounted self-contained evaporator assembly adapted for mounting into the front or rear bulkhead of a bus or similar type vehicle. The evaporator assembly includes a specially designed housing to provide a compact self-contained unit that can fit in a small space, such as the bulkhead above a passenger compartment, while the associated compressor and condenser units are distally located. The housing has chamfered top surfaces so as to provide additional clearance within the bulkhead during installation, and a floor pan with two sloping surfaces forming an inverted apex. Lateral drains located at both ends of the apex facilitate drainage of condensate from the unit when the vehicle is in motion or in a non-level stationary position.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This present invention generally relates to an air conditioning (AC) unit having an evaporator/blower housing adapted for mounting into the front or rear bulkhead of a bus or similar type vehicle for transporting a large number of occupants. More specifically, the invention relates to housings which are small, lightweight and easy to service and which allow evaporator/blower assemblies to be located distally from the compressor/condenser.

2. Description of the Related Art

Air conditioning units have been installed in various types of vehicles, with the design and operating parameters of the AC units adapted for installation in specific types of vehicles. Passenger buses presented particular problems due to the relatively large cooling load produced by the large number of passengers and the extensive window areas. Also, it is difficult to obtain effective air circulation through the large volume of internal space to be cooled. In prior art developments, passenger buses have been provided with AC units mounted on the roof or at other locations with the compressor assembly being driven from the engine which powers the bus. A condenser, condenser fan, evaporator and evaporator fan are associated with a compressor, expansion valve and other conventional components to provide a refrigeration system to supply conditioned air to the interior of the bus.

The following U.S. patents relate to the heating and cooling of a vehicle interior and the occupants therein: U.S. Pat. Nos. 4,201,064; 4,870,833; 5,428,967; 4,622,831; 4,926,655; 5,605,055; 4,727,728; 5,001,905; 5,609,037; 4,748,825; 5,184,474; 5,678,761; 4,787,210; 5,220,808; 6,295,826; and 6,494,052. These patents disclose various roof and rear mounted air conditioning and heating units for buses and other vehicles and are hereby expressly incorporated by reference in their entirety. However, the above listed patents do not disclose a self-contained AC unit which has an evaporator assembly separated and located distally from the compressor and condenser, allowing the evaporator assembly to take up much less space than a prior AC unit. As a result, the prior systems require a considerable amount of space, making them unsuitable for installation within the front or rear bulkhead of a bus or similar vehicle.

Further, one of the problems associated with installing evaporator components inside a vehicle has always been condensation. Water results from the hot humid interior air coming into contact with the cool evaporator surface, and drips onto the bottom of the unit housing where it must be drained away. Often the housing is made of multiple pieces of metal that are welded together. Constant exposure of the metal welds to the water causes corrosion and leakage into the interior of the bulkhead. Furthermore, operation of the AC unit while the bus is in motion can cause drainage problems for standard conventional drain pans, as the water sloshes laterally with the movement of the bus.

Accordingly, a need exists for a compact housing to contain an evaporator assembly that can be mounted in a front or rear bus bulkhead, remotely located from the associated compressor and condenser units. Also needed is a housing having a floor pan which is leak resistant and which facilitates drainage of condensate whether the vehicle is in motion or stationary in a non-level position, and which is shaped to allow for both ease of installation and access for service retrofit.

SUMMARY OF THE INVENTION

In view of the foregoing, the present invention is directed to a self-contained evaporator assembly that is small and lightweight, being designed to be flush mounted to a variety of bulkhead surfaces and particularly to the front or rear bulkhead of a bus or other similar type vehicle in an area above the prime mover of the vehicle which is usually vacant and available. The mounting of the evaporator assembly of the AC unit in this area of the bus enables installation without alteration of the roof or other external configuration of the bus.

According to the present invention, the evaporator assembly includes a coil subassembly, a blower panel subassembly and a generally rectangular housing having a front opening for receiving the coil and blower panel subassemblies therein. The housing has a floor pan with two sloping surfaces that meet to form an inverted apex. In the lateral walls of the housing adjacent each end of the inverted apex is a drain aperture through which condensate from the evaporator can flow to exit the housing. The housing is preferably made from a single piece of metal to reduce corrosion susceptibility, and at least part of the upper surface of the housing is chamfered to facilitate easy installation thereof within a bulkhead opening.

The evaporator housing of the present invention can accommodate a blower panel subassembly equipped with either single or dual evaporator blowers for increased airflow into the passenger compartment, and a plurality of compact coil designs for a variety of installation openings. The evaporator assembly may be used with single or dual compressors and a single skirt-mounted condenser.

It is therefore an object of the present invention to provide a small compact self-contained evaporator assembly, the housing of which can fit into a bulkhead of a bus or similar vehicle.

It is a further object of the present invention to provide a small compact evaporator assembly housing that can be made from a single piece of aluminum or other material.

It is a still further object of the present invention to provide a compact housing for coil and blower subassemblies that is made from two pieces of aluminum or other material.

It is another object of the present invention to provide an evaporator assembly housing that has chamfered top lateral surfaces so as to provide additional clearance with a bulkhead during installation.

It is yet another object of the present invention to provide an evaporator assembly housing having a floor pan with sloping surfaces to facilitate drainage of condensate from the unit.

It is still a further object of the present invention to provide an evaporator assembly housing having a floor pan with two sloping surfaces that meet to form an inverted apex with drain apertures on both lateral sides adjacent the apex to allow drainage of condensate from the unit when the vehicle is in motion or when it is stationary in a non-level position.

It is also an object of the present invention to provide an evaporator assembly housing capable of being fitted with either single or dual blower units.

It is yet a further object of the present invention to provide an evaporator assembly housing which provides openings on either lateral side to allow for connection to separate, distally located, compressor and condenser units.

It is another object of the present invention to provide an evaporator assembly housing having a chamfered upper surface adjacent a rearside to facilitate bulkhead installation.

Yet another object of this present invention to be specifically enumerated herein is to provide an evaporator assembly in accordance with the preceding objects and which will conform to conventional forms of manufacture, be of simple construction and be easy to use so as to provide an assembly and housing that will be economically feasible, long lasting and relatively trouble free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described, reference being had to the accompanying drawings forming a part hereof which illustrate the evaporator/blower assembly and housing of the present invention and their various components and related structure. The drawings are intended to illustrate the present invention and are not necessarily to scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Although only a few preferred embodiments of the present invention are explained in detail, it is to be understood that these embodiments are given by way of illustration only. It is not intended that the invention be limited in its scope to the specific details of construction and arrangement of components set forth in the following description or illustrated in the drawings. Also, in describing the preferred embodiments, specific terminology will be resorted to for the sake of clarity. It is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

The present invention is directed to a self-contained evaporator assembly, generally designated by the reference numeral5(seeFIG. 8B), which includes a housing for an air conditioning system to be used within a bus or similar vehicle. The evaporator assembly includes a coil subassembly, generally designated by the reference numeral66(seeFIG. 6A), and a blower panel subassembly, generally designated by the reference numeral29(seeFIG. 3C).

One embodiment for the housing is illustrated inFIG. 1Aand generally designated by the reference numeral10. As used herein, references to a “bus” are intended to include various types of buses as well as other vehicles within which air conditioning systems are or may be installed.

The housing10with the coil subassembly66and blower panel subassembly29contained therein is preferably mounted below the roof line and above the passenger space in the overhang area or bulkhead12of the bus, as shown inFIG. 1B. The shape of the housing10is suited to fit a cutout14in the bulkhead12.

According to the embodiment shown inFIG. 1A, the housing is generally rectangular in shape and is made of a single piece of aluminum folded to form inwardly directed flanges16. As shown in greater detail inFIG. 2A, the top wall18of the housing10is chamfered along two axes, being beveled on two lateral side surfaces20as well as along a rear surface22so as to decline toward the rear wall24of the housing. The chamfered surfaces20and22facilitate mounting of the housing10within the relatively tight confines of the bulkhead cutout14. The front opening26of the housing, as shown inFIG. 2B, is of sufficient size to provide for ease of installation of the coil subassembly through such opening26.

The housing10is fitted with a removable face plate28which, as shown inFIG. 3A, supports at least one blower louver30and an air inlet grille32, the latter shown from the back side inFIG. 3B. Preferably, damping material is applied to the back surfaces34of the edges around the grille32which is then secured to the face plate28. Alternately, the grille32may be integrally formed with the face plate28as a single unit.

As shown and described herein, the air inlet grille32serves to allow incoming air to pass through the coil subassembly66contained within the housing10while dual mounted blower louvers30are set adjacent to one another for venting of conditioned air back into the passenger compartment of the bus. The venting of conditioned air is effected by at least one blower unit36mounted to the face plate28behind the blower louvers30. The face plate28, louvers30, air inlet grille32and blower unit36together form the blower panel subassembly29, as shown inFIG. 3C.

As illustrated inFIG. 3D, according to the preferred embodiment, a plurality holes or apertures38are punched into either or both lateral walls40of the housing10in the upper half thereof. These holes are positioned adjacent the rear wall24of the housing, but they may be in other configurations depending on the particular evaporator assembly configuration. The holes38allow the passage of wiring elements to make electrical connections to the blower unit36, as well as passage of piping or hoses42in order to make fluid connections between the coil subassembly66and the compressor and condenser units located elsewhere in or on the vehicle (not shown).

As shown inFIGS. 1A and 3D, the floor pan50of the housing10is not flat but rather is designed to facilitate draining, having two sloping surfaces50a,50bthat meet to form an inverted apex52. At each lateral wall40of the housing, adjacent to the floor pan50and positioned at the inverted apex52, a drain aperture54is provided for passage of condensate draining into the floor pan. According to the preferred embodiment shown, a drain tube56is coupled to each drain aperture54for connection of a drain hose or pipe (not shown). The front lip16aof the floor pan50is integral therewith in this embodiment.

The sloped surfaces50a,50bof the floor pan50cause water collecting from condensation in the evaporator assembly5to travel to the bottom of the inverted apex52and exit through the drain apertures54and tubes56. Having drain apertures54on both lateral side walls40ensures that proper drainage is provided even when the vehicle is in motion, making a turn, or in a non-level orientation such as on the slope of a hill, allowing inertia to assist in fluid drainage during vehicle operation.

In the preferred embodiment shown, the inverted apex52where the sloped bottom surfaces50a,50bmeet is positioned so as to be closer to the rear wall24of the housing10than to the front25thereof. The drain tubes56are preferably constructed from aluminum tubing and are welded to the lateral walls40of the housing10.

FIGS. 4A,4B and4C illustrate the face plate28with dual blower units36mounted therein forming the blower panel subassembly29. Specifically, the side-by-side arrangement of the two blower units36as affixed to the face plate28and aligned behind blower louvers30is shown in the top view ofFIG. 4A, with the spatial arrangement of these blower units relative to the air inlet grille32being shown in the rear view ofFIG. 4C. The blower panel subassembly29is removed as a unit when the fasteners holding the face plate28to the housing10are released, allowing access to the coil subassembly66mounted within the housing10.

The number and size of the blower units36is limited primarily by the space available within the housing10. The fans within the blower units are driven in a conventional manner by centrally located electric motors35which, being operated using conventional controls, circulate air from the air inlet grille32through the coil subassembly66and then expel the chilled air through the blower louvers30into the passenger compartment. A more detailed view of the motor35is shown inFIG. 4B.

Other views of the housing with the face plate28removed are provided inFIGS. 5A and 5B. According to the preferred embodiment shown, foam tape58is affixed to the front surfaces of the housing for providing a snug, insulated interface with the face plate28. The face plate is secured to the housing with brackets68. A shelf bracket60on each lateral wall40is used to secure the coil subassembly66within the housing10.FIG. 5Balso depicts the hose apertures38for fluid connection to the coil subassembly66and electrical connection to the blower panel subassembly29.

The housing10is mounted within the bulkhead preferably by angle brackets (not shown), which are fastened to the outside surfaces of the housing and then are attached to internal structural members as may be available within the bulkhead. This readily modified mounting configuration allows the present invention to be installed more easily than conventional units, especially in retrofit applications, due to the adaptability in the angle bracket location permitted by the mounting thereof external to the housing, as well as by the use of hose connections between the evaporator assembly and the compressor and condenser units which allow for distal location of these latter units. The housing may also be affixed to the bulkhead using other various connecting elements as would be known by persons of ordinary skill in the art.

Fitted within the housing adjacent the air inlet grille32is the coil subassembly66, as variously shown inFIGS. 6A,6B,7A and7B. The coil subassembly66includes a conventional rectangular coiled tube and fin heat exchanger, each of which includes end walls. In addition to the shelf bracket60upon which the coil shelf65is secured, the coil subassembly66is supported from the lateral walls40of the housing by attachment to the front lip16aof the floor pan50as at hole70. The coil fins are located behind the air inlet grille32for effective heat exchange with incoming air. When the blower panel subassembly29is removed, the coil subassembly may be accessed as shown inFIG. 7A.

The housing10with the blower panel subassembly29and coil subassembly66installed is shown in the front and sectional views ofFIGS. 8A and 8B, respectively. In the preferred embodiment shown inFIG. 8A, the face plate28is affixed to the housing by the brackets68with fasteners71, such as captive screws or the like. The blower panel subassembly29may be removed as a unit when service is needed, leaving the coil subassembly66secured within the housing10as shown inFIG. 7B. In addition to showing the arrangement of all the components within the housing,FIG. 8Balso shows the hose apertures38in the lateral walls40with hose grommets41to protect hoses passing therethrough for connection to the remotely located compressor and condenser units (not shown).

In order to reduce the size of the housing, the compressor and condenser assembly units are distally located relative to the evaporator assembly. Connection between the coil subassembly and the compressor and condenser units is effected by hose lines42or other coupling components that can enter the evaporator assembly housing10from either lateral wall40thereof depending on the particular installation. In the case of a preferred installation in a school bus, for instance, the evaporator assembly housing10is flush mounted in the front bulkhead of the bus so that, with the compressor unit being positioned in the front engine compartment, the hose connections are shortened; conversely, in a commercial bus embodiment in which the compressor assembly is located with the engine at the rear of the bus, the evaporator assembly within the housing is flush mounted in the rear bulkhead. The condenser is typically located on the side of the bus or on the roof.

A second preferred embodiment of a housing, generally designated by the reference numeral100, for use with the self-contained evaporator assembly in accordance with the present invention is shown inFIGS. 9A,9B,10A,10B,10C,10D and10E. As with the first embodiment, the housing100is generally rectangular in shape. However, unlike the first embodiment, the top wall118of the housing is chamfered along only one axis, being beveled at a rear surface122at a declining angle toward the rear wall124of the housing. In addition, the inverted apex152formed by the two sloped surfaces150a,150bof the floor pan150is generally in the middle of the floor pan150, rather than being offset toward the rear wall124. However, as with the first embodiment, the dual drain apertures154provide for drainage regardless of the vehicle's orientation, e.g., even when the vehicle is angled laterally. The drain apertures154, as before, are preferably coupled to drain tubes156constructed from aluminum tubing and welded to the lateral walls140of the housing100.

According to the second embodiment, the housing100is made with two pieces of aluminum, the first piece101forming the housing enclosure itself while the second piece forms a front lip80, shown inFIG. 10E, which is welded to the front opening126to act as a dam to prevent condensate from spilling out of the front opening126of the housing. The joints between the interfacing walls of the housing and the second piece of metal80are sealed by welding or other suitable means. Whether the housing is made of one or two metal pieces, aluminum is preferred, but other metals or materials may also be used.

A face plate128with dual blower louvers130and air inlet grille132suitable for use with the second embodiment of the housing100is shown inFIGS. 11A and 11B, and as installed in such housing inFIGS. 12A and 12B. One of the blower units136mounted to the face plate128and mounted within the housing100is shown in profile inFIG. 12C, withFIG. 12Ddepicting the blower unit136coupled to the face plate128to form the blower panel subassembly, generally designated by the reference numeral129. Top and rear views of the blower panel subassembly129including the dual blower units with motors135mounted to the face plate128are provided inFIGS. 13A and 13C, respectively; a more detailed view of the motor135is provided inFIG. 13B.

FIGS. 14A and 14Bdepict the coil subassembly166mounted within the second embodiment of the housing100after the blower panel subassembly129has been removed. As shown, the housing may be provided with bulkhead fittings88instead of hose connection elements for connection to the compressor and/or condenser, an option that allows the present invention to accommodate various vehicle mounting arrangements.

An alternate face plate228embodiment for use with the second embodiment of the housing100is shown inFIGS. 15A and 15B. As shown, the alternate face plate228has a single blower louver230and an air inlet grille232; as with all of the embodiments discussed herein, the air inlet grille may be formed as a single piece with the face plate or may be installed separately as shown in the figures. The corresponding position of the single blower unit236with motor235mounted to the alternate face plate228to form a blower panel subassembly, generally designated by the reference numeral229, is shown inFIGS. 16A and 16C, and as installed in the second embodiment of the housing100inFIGS. 17A and 17B. A more detailed view of the motor235is provided inFIG. 16B. The coil subassembly266as mounted beneath the single blower unit236is also shown inFIG. 17B.

The housing compartment for receiving the coil and blower panel subassemblies, and the elements for mounting the coil subassembly and the face plate, are shown inFIGS. 18A,18B and18C, with the coil subassembly being mounted within the housing compartment and connected through bulkhead fittings88to the remotely located compressor/condensor units in the same manner as shown inFIGS. 14A and 14B.

As illustrated by the differences between the face plates of the first and second embodiments, the face plate may have varying dimensions and may be constructed to accommodate single or dual blower units. Additional blowers could also be built into a particular face plate embodiment should space be available in the intended vehicle mounting location.

As described herein, the evaporator assembly may be implemented with any type of compressor and condenser arrangement. In a preferred embodiment, a dual compressor system is used. Further preferred embodiments can include the use of TM-21X heavy duty compressors made by Seltec Selective Technologies of Dallas, Tex. In addition, the present invention will preferably use a SMC3L skirt mounted condenser such as that made by Trans/Air Mfg. Corp. of Dallastown, Pa.

The foregoing descriptions and drawings should be considered as illustrative only of the principles of the invention. The invention may be configured in a variety of shapes and sizes and is not limited by the dimensions of the preferred embodiment. Numerous applications of the present invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.