EXTRUDED EVAPORATOR DRAIN PAN
A drain pain is disclosed. The drain pain includes a base sheet, an extruded covering sheet coupled to the base sheet, the extrusion defining a tube cavity having a heat transfer surface, and a heat tube inserted into the tube cavity. The tube cavity has dimension such that the heat transfer surface is in contact with the heat tube.
This application claims the benefit of U.S. Provisional Application No. 61/360,006 filed Jun. 30, 2010, the entire content of which is incorporated herein by reference.
FIELD OF INVENTIONThe present invention relates to an evaporator drain pan, particularly for use in a defrost cycle in a refrigeration system.
BACKGROUND OF THE INVENTIONRefrigeration systems affect our lives in many ways. For example, refrigerators keep our food from spoiling, freezers prevent ice cream from melting, and air conditioners create comfortable living space even in the hottest weather. It is hard to imagine a world before the invention of refrigeration systems.
A typical refrigeration system includes a compressor 10, a condensor 12, an expansion valve 14 and an evaporator 16, with a refrigerant circulating through these components as shown in
However, as the evaporator coils 18 cool, frost forms on the surface. Many have witnessed this in older refrigerators with freezers where frost build up eventually rendered the freezer useless. As such, modern refrigerators have a defrost cycle in addition to the refrigeration cycle to ensure that frost does not accumulate. Generally speaking, defrost cycle applies heat to the evaporator coils 18 at a predetermined time in-between refrigeration cycles to remove any frost from building up on the evaporator coils 18. This can be achieved either by activating heating coils or by applying hot gas. The former entails turning on heating coils (embedded in-between the evaporator coils 18) in the evaporator 16 to melt away any frost build-up, while the latter involves redirecting the hot refrigerant gas from the compressor 10 into the evaporator coils 18 in the evaporator 16. While heating coils defrost the evaporator coils 18 faster than hot gas defrost systems, it is less energy efficient and more expensive to implement.
Similarly to evaporator coils 18, drain pan 20 may also be defrosted using heat coils rather than hot gas. However, while defrost time is reduced, such defrost systems suffer from the same disadvantages as discussed above.
Hot gas defrost systems can be generally divided into two types of systems: reverse cycle defrost (
As for the 3-pipes defrost system, the hot refrigerant gas from the compressor 10 is redirected to the hot gas line 22 of the evaporator 16. In the evaporator 16, the hot gas flows through the drain pan 20 to remove any frost build-up and then bypasses expansion valve 14 by flowing through the check valve 26. The hot gas then flows through the distributor 24 and into the evaporator coils 18 to remove any frost build-up. The refrigerant, which is now a liquid, is pumped out of the evaporator coils 18 by the suction line 23. The refrigerant eventually makes its way back to the compressor 10.
A typical drain pan 20 using hot gas defrosting system is shown in
In accordance with an aspect of the invention, a drain pan is disclosed. The drain pain includes a base sheet, an extruded covering sheet coupled to the base sheet, the extrusion defining a tube cavity having a heat transfer surface, and a heat tube inserted into the tube cavity. The tube cavity has dimension such that the heat transfer surface is in contact with the heat tube.
In according with a further aspect of the invention, a refrigeration system including a compressor, a condensor, an expansion valve and an evaporator, the evaporator including an evaporator coil and a drain pan, in fluid connection is disclosed. During a refrigeration cycle and a defrost cycle, a refrigerant circulates through the refrigeration system. In the refrigeration system, the drain pan includes a base sheet, an extruded covering sheet, the extrusion defining a tube cavity having a heat transfer surface, and a heat tube inserted into the tube cavity. The tube cavity having dimension such that the heat transfer surface is in contact with the heat tube.
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein:
While the patent disclosure is described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the patent disclosure to the described embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the scope of the patent disclosure as defined by the appended claims. In the description below, numerous specific details are set forth in order to provide a thorough understanding of the present patent disclosure. The present patent disclosure may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail in order not to unnecessarily obscure the present patent disclosure.
In this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs.
It will be further understood that the terms “comprises” or “comprising”, or both when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The details and particulars of these aspects of the present invention will now be described below, by way of example, with reference to the attached drawings.
An embodiment of the present invention is shown in
Now referring to
Turning to
The tube cavity 120 is dimensioned such that when the heat tube 106 is inserted into the heat cavity 120, the heat transfer surface 121 of the tube cavity 120 is in direct contact with the heat tube 106. Thus, when the hot refrigerant passes through the heat tube 106 during the defrost cycle, heat from the heat tube 106 can be transferred directly to the extruded covering sheet 102, 104. Since the heat transfer surface 121 provides a large surface contact area between the extruded covering sheet 102, 104 and the heat tube 106, the drain pan 100 may be efficiently and quickly defrosted. In one embodiment of the present invention, the diameter of the tube cavity 120 is 0.5 inch. Additionally, to increase the contact between the heat tube 106 and the heat transfer surface 121 of the tube cavity 120, the heat tube may be expanded using an expander to ensure good contact between the heat tube 106 and the heat transfer surface 121.
By contrast, in the drain pan 20 (see
In a further embodiment of the present invention, additional cavities may be provided. As shown in
In the particular embodiment shown, the covering sheet is made of two opposing extruded covering sheets 102 and 104. They are mirror images of one another and positioned so that the two opposing extruded covering sheets 102, 104 abut at an edge 130. To securely assemble the two opposing extruded covering sheets 102, 104, they may be welded together upon joining. The opposing covering sheets 102, 104 may also include a chamfer 132, 134 to facilitate welding of the covering sheets 102, 104. The covering sheets 102, 104 and the base sheet 110 may also be welded together.
Alternatively, or additionally, the opposing extruded covering sheets 102, 104, heat tube 106, insulating foam 108 and base sheet 110 may be joined together by a joining cap 112, 114 (see
The drain pan 100 as discussed above is suitable for any refrigeration system that normally requires a drain pan and that utilizes hot gas as the defrost mechanism. Previous implementations of heat tubes in drain pan (such as those shown in
Referring to
One or more currently preferred embodiments have been described by way of example. It will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention.
Claims
1. A drain pan comprising:
- a base sheet;
- an extruded covering sheet coupled to the base sheet, the extrusion defining a tube cavity having a heat transfer surface; and
- a heat tube inserted into the tube cavity;
- wherein, the tube cavity having dimension such that the heat transfer surface is in contact with the heat tube.
2. The drain pan according to claim 1, wherein the extruded covering sheet comprises two opposing covering sheets, the opposing covering sheets abutting at an edge.
3. The drain pan according to claim 2, wherein each of the opposing covering sheets having a slant toward the edge of abutment to define a collection area, the collection area being the area along the slant having the lowest elevation.
4. The drain pan according to claim 1, further comprising an insulation foam positioned between the base sheet and the covering sheet.
5. The drain pan according to claim 1, wherein the extrusion defines a plurality of tube cavities, each of the plurality of tube cavities having a heat transfer surface.
6. The drain pan according to claim 5, wherein a plurality of heat tubes are inserted into the plurality of tube cavities.
7. The drain pan according to claim 1, wherein the covering sheet further comprises an inset.
8. The drain pan according to claim 1, wherein the tube cavity comprises a slit to accommodate the expansion of the heat tube.
9. The drain pan according to claim 1, wherein the heat tube is made of copper.
10. The drain pan according to claim 1, wherein the extruded covering sheet is made of aluminium.
11. The drain pan according to claim 1, wherein the base sheet and the covering sheet are coupled by welding the sheets together.
12. The drain pan according to claim 1, wherein the base sheet and the covering sheet are coupled together by a joining cap.
13. The drain pan according to claim 1, wherein the tube cavity is circular in cross-section, the circular cross-section having a diamer and a circumferential edge.
14. The drain pan according to claim 13, wherein the diameter is approximately 0.5 inch.
15. The drain pan according to claim 13, wherein the circumferential edge comprises the heat transfer surface.
16. The drain pan according to claim 1, wherein the heat tube is expanded using an expander for increasing the contact between the heat tube and the heat transfer surface.
17. A refrigeration system comprising a compressor, a condensor, an expansion valve and an evaporator, the evaporator including an evaporator coil and a drain pan, in fluid connection, a refrigerant circulating through the refrigeration system during a refrigeration cycle and a defrost cycle, the drain pan comprising:
- a base sheet;
- an extruded covering sheet, the extrusion defining a tube cavity having a heat transfer surface; and
- a heat tube inserted into the tube cavity;
- wherein, the tube cavity having dimension such that the heat transfer surface is in contact with the heat tube.
18. The refrigeration system according to claim 17, wherein the extrusion defines a plurality of tube cavities, each of the plurality of tube cavities having a heat transfer surface.
19. The refrigeration system according to claim 18, wherein a plurality of heat tubes are inserted into the plurality of tube cavities.
Type: Application
Filed: Nov 16, 2010
Publication Date: Jan 5, 2012
Applicant: Refrigeration Kool-Air Inc. (Delson)
Inventor: Patrice LaFontaine (Beloeil)
Application Number: 12/947,249
International Classification: F25D 21/14 (20060101); B65D 1/34 (20060101); F25B 1/00 (20060101);