Patent Application
20070151169
1. Field of the Invention
The subject invention generally pertains to HVAC air handling enclosures and more specifically to a thermal break and panel joint for such an enclosure.
2. Description of Related Art
Heat exchangers, compressors, blowers, filters and other HVAC equipment are often housed within an air handling 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 enclosures usually comprise a number of sheet metal panels that are interconnected to create a box-like 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 system, some localized heat loss may still occur at the uninsulated metal-to-metal 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 and U.S. Pat. Nos. 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, some consider exposed seals unsightly. U.S. Pat. No. 6,374,571 shows how a panel with a hidden seal can be attached to a frame member, but then, of course, the enclosure requires a frame, which adds cost to the enclosure.
Consequently, a need exists for providing an air handling enclosure with insulated panels and a hidden thermal break at the joints without having to add a frame to help support the panels.
It is an object of the present invention to provide an air handling enclosure with self-supporting insulated panels that include a hidden thermal break at the joints.
Another object of some embodiments is to provide a seal that serves as both a thermal break and a fastener for holding a panel's inner and outer skins together.
Another object of some embodiments is to use double-sided tape that serves as both a thermal break and a fastener for holding a panel's inner and outer skins together.
Another object of some embodiments is to provide a thermal break for a 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 provide a panel with an edge that lies at a slight acute angle to the face of the panel so that when the edge abuts a similar edge of an adjoining panel, the two panels close any visible gap that might otherwise exist.
Another object of some embodiments is to connect two panels with a solid metal-to-metal tongue-and-groove joint, and yet provide that solid joint with a thermal break.
Another object of some embodiments is to connect two adjoining panels with tongue-and-groove joint that allows a sealing compound to be introduced deeply inside the groove. If any compound oozes out from within the groove, the slightly angled edges of the panels create a cavity to take up any excess compound so that the entire sealing compound preferably remains hidden between the joint.
Another object of some embodiments is to connect two panels with a tongue-and-groove joint, wherein the tongue and groove are formed as an integral extension of the panel sheets that provide the outer faces of each panel, thereby minimizing the number of parts and maximizing the panels' strength.
Another object of some embodiments is to provide a panel assembly with one tape held in compression and one held in tension, whereby the opposing forces provide a tight resilient connection within a tongue-and-groove joint.
One or more of these and/or other objects of the invention are provided by an air handling enclosure whose individual panel assemblies are taped together, and adjacent panel assemblies are connected by a tongue-and-groove joint that relies on that same tape as a thermal break at the joint.
Enclosure 12 can be made of any number of insulated panel assemblies 22, 24,26, 28, and 30 that have a thermal insulating core sandwiched between inner and outer panel sheets. The inner and outer panel sheets are held together with double-sided tape. The tape also provides a thermal break where adjoining panel assemblies come together at a tongue-and-groove joint. Details of some embodiments of assemblies 22, 24, 26, 28, and 30 are shown in
Referring to the right side of
At end 48 (
At end 44 of panel assembly 24 (
Panel assembly 22 is similar to panel assembly 24 in that assembly 22 comprises an outer panel 70, an outer tongue edge 72, an outer tongue flange 74, an inner panel 76, an inner tongue edge 78, an inner tongue flange 80, insulating core 34, and a strip of double-sided tape 82 that bonds inner tongue flange 80 to outer tongue flange 74 to create a tongue 84. An opposite end 86 of panel assembly 22 could be similar to an end 92 of panel assembly 26, or in some cases, end 86 could be similar to end 48. For strength and ease of manufacture, the inner panels and their metal tongue and groove elements are formed from a unitary piece of sheet metal. The same is true for the outer panels. For panel assembly 24, for example, outer panel 36, outer groove edge 50, outer groove flange 52, outer tongue edge 60, and outer tongue flange 62 comprise a unitary piece.
To connect panel assemblies 22 and 24 together, an adhesive sealant 90 is injected into the base of groove 46 prior to inserting tongue 84 of panel assembly 22 into groove 46 of panel assembly 24. Sealant 90 not only provides an effective seal at joint 40, but the adhesive properties of sealant 90 helps hold panel assemblies 22 and 24 together. A variety of adhesive sealants could be used, but in a currently preferred embodiment, sealant 90 is a 221-Sikaflex sealant provided by Sika Corporation of Baar, Switzerland (with various branch locations including Lyndhurst, N.J.).
To provide a clean, attractive joint, edges 50, 54, 72 and 78 each lie at a slightly acute angle 88 to its respective panel 36, 38, 70 and 76. Angle 88 is between 80 and 90 degrees and is preferably about 88-degrees. Angle 88 ensures that the two adjoining outer panels 36 and 70, and the two adjoining inner panels 38 and 76 come in direct contact with each other at the surface where panel assemblies 22 and 24 are most visible. Angle 88 also creates a gap 94 between edges 50 and 72, and between edges 54 and 78. Gap 94 provides a space into which surplus sealant 90 can ooze without being noticeable once enclosure 12 is assembled.
It should be noted that although tape strips 58, 68, and 82 couple inner panels 38 and 76 to outer panels 36 and 70, the tape strips also provide a thermal break between the inner and outer panels, as strips 58, 68, and 82 have a much lower thermal conductivity than the sheet metal material of the panels. To provide a resiliently tight fit at the tongue-and-groove joint 40, tape 58 is in tension, and tape 82 is in compression. If a metal stiffener 96 is added between the inner and outer panels, a strip of double-sided tape 98 can provide a thermal break for that as well.
Although the invention is described with respect to a preferred embodiment, modifications thereto will be apparent to those of ordinary skill in the art. Therefore, the scope of the invention is to be determined by reference to the following claims.
