ELECTRIC HEATER BRACKET ARRANGEMENT
A plurality of resistance heater rods are assembled in parallel relationship between the plurality of normally extending brackets and their associated retainers to comprise a subassembly which is then attached as a unit to an evaporator coil. Each of the coils is a continuous element that forms a complete loop with the ends then overlapping such that they are generally centrally located but are located on either side of midpoint such that their movement is not interfered with by other existing structures.
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This application claims the benefit of and priority from U.S. Provisional Patent Application Ser. No. 61/031,182, filed Feb. 25, 2008, and entitled: Electric Heater Bracket Arrangement.
TECHNICAL FIELDThis invention relates generally to refrigeration systems and, more particularly, to a bracket for attaching a heater to an evaporator coil thereof.
BACKGROUND OF THE INVENTIONIn transport refrigeration systems, an evaporator coil is provided to cool the air that is circulated within a cargo space to be cooled. Since such an evaporator coil has a tendency to frost up during certain environmental conditions, and since there are periods in which heating of the cargo space is required rather than cooling, one common approach has been to provide an electrical resistance heater at or near the evaporator coil for either or both of those purposes. One such design is shown in U.S. Pat. No. 6,298,680 granted on Oct. 9, 2001 and assigned to the assignee of the present invention. In that design, a plurality of heater rods are individually nested in grooves formed in one face of the evaporator coil, and a plurality of brackets are then placed over the individual rods to thereby secure them in place. With this approach, the individual rods are firmly pressed and held in close contact to the coil such that any expansion or contraction along their longitudinal axes tends to cause thermal stress therein, as well as frictional wear on the rods. Also, since the lead wires going to the terminals are attached at one end of the heater rods, the wires can be damaged by that end of the heater rod contacting a surface which is perpendicular to the longitudinal direction of the heater rod, such as a tube sheet for the coil.
DISCLOSURE OF THE INVENTIONIn accordance with one embodiment of the invention, a plurality of heater rods are preassembled by insertion against the sides of a plurality of brackets, with a retainer member then being secured on the other side of the rods to hold them in place. This subassembly can then be easily attached to one side of an evaporator coil, with the heater rods being free to expand or contract within their subassembly.
By another aspect of the invention, the terminal ends of the heater rods pass by each other in a paperclip manner at the nominal center of the heater rod and are turned up at some angle. This angle occurs on either side of the central bracket such that heater rods are not constrained in the longitudinal direction and can be moved freely.
The invention is shown generally at 10 in
As will be seen in
The completed subassembly, which includes the three brackets 12, 13 and 14, the six heater rods 21-27 and the three retainer members 31, can then be installed as a unit to the one side of the evaporator coil 19 as shown in
Referring again to
While the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawings, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims.
Claims
1. A resistance heater assembly for attachment to an evaporator coil comprising:
- a plurality of elongate brackets arranged in mutual parallel relationship;
- a plurality of resistance heater rods aligned in mutual side-by-side parallel relationship and aligned normally with respect to said plurality of brackets, said heater rods being installed against one side of by said brackets; and
- a retainer member associated with each of said brackets, said retainer members being attachable to said respective brackets to complete a subassembly which, in turn, is attachable as a unit to the evaporator coil.
2. A resistance heater assembly as set forth in claim 1 wherein at least some of said plurality of elongate brackets include on their one side a plurality of scallops for receiving said resistance heater rods.
3. A resistance heater assembly as set forth in claim 1 wherein at least some of said retainer members include a plurality of scallops for receiving said resistance heater rods therein.
4. A resistance heater assembly as set forth in claim 1 wherein said plurality of resistance heater rods are formed in continuous elements which extend from one end, in a first direction to a return bend, in the opposite direction to an other return bend, and then back in the first direction to the other end, with said one end and other end overlapping on either side of a central position of said rod.
5. A resistance heater assembly as set forth in claim 4 wherein said resistance heater rods are bent near their one end and other end such that said one end and other end extend obliquely from the longitudinal direction.
6. A resistance heater assembly as set forth in claim 5 wherein said bends are spaced from a bracket disposed therebetween.
7. A resistance heater assembly for attachment to an evaporator coil comprising:
- a plurality of resistance heater rods aligned in mutual side-by-side parallel relationship with each of said rods being formed in a continuous element which extends from one end, in a first direction to a return bend, in the opposite direction to an other return bend, and then back in the first direction to the other end, with said one end and other end overlapping on either side of a central position on said rods; and
- a plurality of brackets for receiving of said heater rods; and
- a plurality of retainer members for securing said heater rods to said respective brackets; with the heater assembly then being attached as a unit to the evaporator coil.
8. A resistance heater assembly as set forth in claim 7 wherein at least some of said plurality of brackets include on their one side a plurality of scallops for receiving said resistance heater rods.
9. A resistance heater assembly as set forth in claim 7 wherein at least some of said retainer members include a plurality of scallops for receiving said resistance heater rods therein.
10. A resistance heater assembly as set forth in claim 7 wherein said resistance heater rods are bent near their one end and other end such that said one end and another end extend obliquely from the longitudinal direction.
11. A resistance heater assembly as set forth in claim 10 wherein said bends are spaced from a bracket disposed therebetween.
Type: Application
Filed: Feb 24, 2009
Publication Date: Aug 27, 2009
Applicant: CARRIER CORPORATION (Farmington, CT)
Inventors: Mark J. Perkovich (Fayetteville, NY), Stephen Stopyra (Syracuse, NY), Joseph Searor (Fulton, NY)
Application Number: 12/391,776
International Classification: F25D 21/08 (20060101);