FIELD OF INVENTION

The present invention relates to a door frame for an air handling unit. More specifically, relates to an enclosure for air handling unit with self-supporting insulated panels that include a thermal break at the joints.

BACKGROUND OF INVENTION

Equipment used in air handling unit such as compressors, blowers, and filters are often housed within an air handling unit enclosure. The enclosure helps shelter the equipment, provides a sound barrier, and perhaps most importantly, the enclosure provides a conduit for directing the air through the equipment. Air handling unit enclosures usually comprise a number of flat panels that are connected to create a boxlike structure.

In many cases, the panels are insulated to minimize heat loss between the interior and exterior of the enclosure. Although such insulation can improve the operating efficiency of the air handling unit, some localized heat loss may still occur at the uninsulated metal-to-metal corner joint where two panels come together. Such localized heat loss may be inconsequential to the system's overall efficiency; however, when there is a significant temperature differential between the interior and exterior of the enclosure, condensation may form on the joint. The condensation can lead to poor air quality, water damage or create a wet, slippery floor around the enclosure. In some cases, the condensation may freeze, and the accumulating frost can provide a poor appearance or prevent doors or other moving parts of the enclosure from operating.

Some enclosures have a non-metallic seal that lines one or more edges of each panel. Examples of such seals are disclosed in publication WO 94/24493, U.S. Pat. No. 6,676,234 and 2,647,287. These seals, however, are visible and may be exposed to sunlight whose ultraviolet radiation may hasten their deterioration.

Moreover, many known air handling unit enclosures use rivets to form the connection at the corner joint where two panels come together. This calls for additional tools and equipment. Furthermore, metal rivets defeat the purpose of having insulated joints, and condensation may occur locally at the area surrounding the rivets.

Consequently, a need exists for providing an air handling unit enclosure with insulated panels and a thermal break at the joints.

A need also exists for an air handling unit enclosure that is easy to install.

SUMMARY OF INVENTION

It is an object of the present invention to provide an air handling enclosure with self- supporting insulated panels that include a thermal break at the joints, and that is easy to install.

Another object of some embodiments is to provide a thermal break for a corner joint that connects two panels end-to-end in direct contact with each other (i.e., in metal-to- metal contact with the exception of an inconsequential layer of paint or some other relatively thin coating).

Another object of some embodiments is to connect each panel to an angle lug with a solid tongue-and-groove connection, and to strengthen that connection with a strong adhesive.

This invention relates to a door frame for an air handling unit is comprised of individual flat panel assemblies that are connected to form a rectangular structure by angle lugs provided at each corner. The angle lugs are provided with grooves into which tongues on the panels can slide. Adhesive is used to strengthen the connection between the angle lugs and the panels. The angle lugs are made from a low thermal conducting material such as acrylonitrile butadiene styrene to minimize condensation on external surfaces when in use.

This invention also relates to a door frame for an air handling unit, comprising: a top panel; a bottom panel; a pair of side panels; a first pair of angle lugs connecting each end of the top panel to upper end of the side panels; a second pair of angle lugs connecting each end of the bottom panel to lower end of the side panels; and a means of attaching a door in a hinged fashion to be engagable with the frame. The angle lugs are connected to the panels by adhesive. In a preferred embodiment, the adhesive is cyanoacrylate. The angle lugs may be provided with grooves into which tongues on the panels can slide to form a substantially rectangular structure.

In a preferred embodiment, the angle lugs are manufactured from a material or combination thereof that minimizes condensation on external surfaces of the angle lugs, such as acrylonitrile butadiene styrene.

In another preferred embodiment, the panels are manufactured from a material that is a good thermal insulator so as to minimize condensation on external surfaces of the panels, such as polyvinyl chloride (PVC).

In other embodiments, the panels may be made of other materials, such as aluminum.

Other objects and advantages will be more fully apparent from the following disclosure and appended claims. BRIEF DESCRIPTION OF DRAWINGS

Figure 1 shows a front view of a door frame in an embodiment of this invention. Figure 2 shows a side view of a door frame in an embodiment of this invention.

DETAILED DESCRIPTION OF INVENTION

It should be noted that the following detailed description is directed to a door frame for air handling units and is not limited to any particular size or configuration but in fact a multitude of sizes and configurations within the general scope of the following description.

Figure 1 shows a door (110) and frame (1) forming an enclosure for an air handling unit. The door (110) is attached in a hinged manner to the frame (1) via a pair of hinges (120, 125) and having a handle (140) for manual gripping to facilitate opening and closing of the door (110) and a pair of latches (130, 135) to lock the door (110) to the frame (1). Since a temperature differential usually exists between the enclosure's interior and exterior, the enclosure is preferably insulated. A plastic cap (150) further seals the boundary between the door (110) and frame (1). The frame comprises a flat sheet top panel (10) in a horizontal position connected at each end to upper ends of a pair of flat sheet side panels (30, 40) both in a vertical position by a first pair of angle lugs (50, 60). This first pair of angle lugs (50, 60) having appropriately formed grooves into which tongues formed on the panels can slide. The connections between this first pair of angle lugs (50, 60) and the top and side panels (10, 30, 40) are further strengthened using a strong adhesive. In one embodiment, this adhesive is cyanoacrylate. A flat sheet bottom panel (20) completes the rectangular structure, connecting at each end to lower ends of each the side panel (30, 40) by a second pair of angle lugs (70, 80). This second pair of angle lugs (70, 80) having appropriately formed grooves into which tongues formed on the panels can slide. The connections between this second pair of angle lugs (70, 80) and the bottom and side panels (20, 30, 40) are further strengthened using a strong adhesive. In one embodiment, this adhesive is cyanoacrylate.

Referring now to Figure 2, which shows a side view of the door (110) and frame (1) forming an enclosure for an air handling unit. The door (110) is attached in a hinged manner to the frame (1) and having a handle (140) for manual gripping to facilitate opening and closing of the door (110) and a pair of latches (130, 135) to lock the door (110) to the frame (1). The door is filled with an inner layer of Polyurethane (PU). In one embodiment, this layer is about 42mm thick. The frame (1) comprises a flat sheet top panel in a horizontal position connected at each end to upper ends of a pair of flat sheet side panels both in a vertical position by a first pair of angle lugs (50, 60). This first pair of angle lugs (50, 60) having appropriately formed grooves into which tongues formed on the panels can slide. The connections between this first pair of angle lugs (50, 60) and the top and side panels are further strengthened using a strong adhesive. In one embodiment, this adhesive is cyanoacrylate. A flat sheet bottom panel completes the rectangular structure, connecting at each end to lower ends of each the side panel by a second pair of angle lugs (70, 80). This second pair of angle lugs (70, 80) having appropriately formed grooves into which tongues formed on the panels can slide. The connections between this second pair of angle lugs (70, 80) and the bottom and side panels are further strengthened using a strong adhesive. In one embodiment, this adhesive is cyanoacrylate.

While several particularly preferred embodiments of the present invention have been described and illustrated, it should now be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are intended to embrace such changes, modifications, and areas of application that are within the spirit and scope of this invention.