US20100288467A1 - Explosion-proof enclosures with active thermal management by heat exchange - Google Patents

Abstract

Enclosures for use in hazardous areas include heat exchangers for active thermal management. The enclosures are coupled to a device having heat transfer capabilities. Equipment within the enclosures produces heat within the enclosure. The heat exchanger removes heat produced from the equipment and manages the internal temperature of the enclosures to a level suitable for hazardous locations. The enclosures can be actively cooled or heated using the device.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is related to U.S. patent application Ser. No. 12/435,807, titled “Explosion-Proof Enclosures with Active Thermal Management Using Sintered Elements” and filed on May 5, 2009, in the name of Joseph Michael Manahan et al, the entire disclosure of which is hereby fully incorporated herein by reference.
TECHNICAL FIELD
• The invention relates generally to explosion-proof enclosures, and, more particularly, to explosion-proof enclosures having active thermal management capabilities using heat exchange.
BACKGROUND
• Automation equipment can be used to preserve the life of devices such as motors and pumps by improving device performance. However, the installation of automation equipment in hazardous or explosive environments typically has been avoided due to the high heat generated by components of the automation equipment, which could result in an explosion. Hazardous area requirements dictate that such equipment must be sealed from the surrounding atmosphere to fully contain any possible sources of ignition within the enclosure, thus preventing propagation of an explosion.
• The automation equipment could potentially be housed in an explosion-proof enclosure. Currently, explosion-proof enclosures rely on conductive heat transfer for dissipating heat produced by equipment within the enclosure. However, these enclosures do not adequately dissipate the heat produced by the automation equipment within and thus could cause a decrease in the life of the equipment or lead to an explosion within the enclosure. As a result, automation equipment is typically installed outside the boundaries of the hazardous area and long electrical cables are run to the devices within the hazardous area. Several disadvantages to this configuration exist. For example, this configuration results in lack of control at the device, as well as an increase in installation, and/or maintenance costs.
• Therefore, a need exists in the art for an explosion-proof enclosure having automation and other equipment that can provide active thermal management in a hazardous area.
SUMMARY
• The present invention can satisfy the above-described need by providing enclosures for use in hazardous areas and having heat exchangers. As used herein, the term “heat exchanger” refers to any device that transfers heat from one medium to another or to the environment. The heat exchangers aid in regulating the internal temperature of an enclosure by actively cooling or heating equipment housed within the enclosure.
• The enclosures of the present invention include a heat exchanger device coupled thereto. In some aspects, the heat exchanger is a thermoelectric cooler, a shell and tube heat exchanger, a plate heat exchanger, or a spiral heat exchanger. The enclosures include equipment housed therein. A heat exchanger is in communication with the internal equipment and external environment, and actively transfers heat from within the enclosure to outside of the enclosure, thereby removing heat produced from the equipment within the enclosure. In certain aspects of the invention, the heat exchanger actively transfers heating from outside the enclosure to within the enclosure, thereby heating the equipment within the enclosure. In certain aspects of the invention, the heat exchanger device are controlled by a control system having a sensor and a controller.
• The enclosures also can include at least one fan positioned proximate to the heat exchanger device. The fan can be positioned within the enclosure or externally mounted to the enclosure. The fan can be controlled by a control system having a sensor and a controller.
• These and other aspects, objects, and features of the invention will become apparent to those having ordinary skill in the art upon consideration of the following detailed description of exemplary embodiments exemplifying the best mode for carrying out the invention as presently perceived.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of an explosion-proof enclosure with the cover removed according to an exemplary embodiment.
• FIG. 2 is a cross-sectional view of the explosion-proof enclosure shown inFIG. 1 according to an exemplary embodiment.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
• This application discloses enclosures having active thermal management capabilities. The enclosures include a heat exchanger that aids in dissipating heat from within the enclosure. The enclosures can be used for both general purposes and in hazardous areas.
• The present invention may be better understood by reading the following description of non-limiting embodiments with reference to the attached drawings wherein like parts of each of the figures are identified by the same reference characters.
• FIGS. 1 and 2 are perspective and cross-sectional views of an explosion-proof enclosure100 with a cover (not shown) removed. Theenclosure100 includes arectangular housing102. Thehousing102 includes atop wall102a,abottom wall102b,twoside walls102c,arear wall102d,and acavity102e.Thehousing102 also includes aflange102fextending orthogonally from the top, bottom, and twoside walls102a,102b,102c.In certain embodiments, thehousing102 is constructed from aluminum and is a NEMA 7 compliant enclosure for indoor or outdoor use in locations classified as Class I, Groups A, B, C, or D.
• Theenclosure100 also includesautomation equipment110 positioned within thecavity102eand coupled to therear wall102d.In alternative embodiments, theautomation equipment110 can be coupled to thetop wall102a,thebottom wall102b,or one of theside walls102c.Theautomation equipment110 produces heat within theenclosure100 which should be dissipated to maintain a desired temperature within theenclosure100. In certain embodiments, theautomation equipment110 may include a controller, such as a variable frequency drive (VFD) that controls the frequency of electrical power supplied to an external device, such as a pump or a motor (not shown). In certain embodiments, theautomation equipment110 may also include a transformer, a programmable logic controller (PLC), and/or a line reactor.
• Theenclosure100 also includes a heat exchanger system that includes aheat exchanger120 and aplate130. Theheat exchanger120 is coupled to the exterior of thehousing102. Theheat exchanger120 may be coupled to thehousing102 by any suitable means, such as by mating threads or by bolting a flange (not shown) on theheat exchanger120 to thehousing102. In certain alternative embodiments, theheat exchanger120 can be positioned in proximity to thehousing102 but not be attached.
• Theplate130 of the heat exchanger system is positioned within thecavity102e.In certain embodiments, theplate130 is coupled to theautomation equipment110. In certain embodiments, theplate130 also is coupled to theside wall102c.Theplate130 is fabricated from thermally conductive material. Suitable examples of thermally conductive materials include, but are not limited to, copper, aluminum, titanium, stainless steel, other metal alloys, and thermally conductive polymers. In certain embodiments, theplate130 may be constructed from multiple thin plates. The size and shape of theplate130 can be configured based on the amount of heating or cooling desired. In certain embodiments, theplate130 is constructed from copper or aluminum.
• Theheat exchanger120 is in communication with theplate130 viainlet pipe134 andoutlet pipe136. The inlet andoutlet pipes134,136 are coupled to theheat exchanger120 to theplate130 through theside wall102c.The inlet andoutlet pipes134,136 may be sealed within theside wall102cso as to maintain the hazardous rating integrity of theenclosure100. In certain embodiments, the automation equipment releases heat, which is absorbed by theplate130. A cooled fluid flows from theheat exchanger120 through theinlet pipe134. The cooled fluid enters a cavity (not shown) within theplate130 and absorbs heat from theplate130 before exiting theenclosure100 throughoutlet pipe136 as a heated fluid. The heated fluid returns to theheat exchanger120 where it is cooled again before returning to theplate130 viainlet pipe134.
• In certain alternative embodiments, theenclosure100 may include equipment (not shown) that requires heating. In these instances, a heated fluid flows from theheat exchanger120 through theinlet pipe134. The heated fluid enters the cavity (not shown) within theplate130 and gives off heat to theplate130, which in turn heats the equipment within the enclosure, before exiting theenclosure100 throughoutlet pipe136 as a cooled fluid. The cooled fluid returns to theheat exchanger120 where it is heated again before returning to theplate130 viainlet pipe134.
• The heat exchanger systems of the present invention can be any device capable of heating and/or cooling equipment within theenclosure100 by heat transfer. Suitable examples of heat exchanger devices include, but are not limited to, Peltier devices or thermoelectric coolers, shell and tube heat exchangers, plate heat exchangers, and spiral heat exchangers. In certain embodiments, the heat exchanger devices are integrated into thehousing102 and a first portion of the heat exchanger device interfaces with the interior of theenclosure100 and a second portion of the heat exchanger device is positioned exterior to theenclosure100.
• In certain embodiments, a fan (not shown) may be positioned within thehousing102 and proximate to theplate130 to facilitate heat transfer. The fan can be powered by an internal power source, such as a battery (not shown), or receive power from a source (not shown) external to theenclosure100. In certain alternative embodiments, a fan (not shown) may be externally mounted to thehousing102 to facilitate heat transfer. One having ordinary skill in the art will recognize that any number of configurations having a fan are possible.
• In certain embodiments, theenclosure100 may include a control system (not shown) for monitoring and controlling the heat exchanger system. In certain embodiments, the control system monitors and controls a fan. The control system generally includes a sensor that is coupled to a controller that controls the heat exchanger system and/or the fan. The sensor actively or passively monitors conditions within theenclosure100. Based on the conditions within theenclosure100, the controller can turn on or off the heat exchanger system and/or the fan. For example, the sensor may be a temperature gauge that senses the temperature within theenclosure100. When the sensor indicates that the temperature within theenclosure100 is too high, the controller turns on the heat exchanger system and/or a fan inside theenclosure100 to remove heat from within thehousing102 to an exterior of thehousing102. Similarly, when the sensor indicates that the temperature within theenclosure100 is low, the controller can turn on the heat exchanger system and/or a fan externally mounted to theenclosure100 to heat the air within theenclosure100. In some embodiments, the control system cycles on and off passively. For example, the control system can cycle such that the heat exchanger system and/or a fan is active for ten minutes every thirty minutes. In certain embodiments, the control system includes a sensor capable of detecting humidity changes within theenclosure100. If the sensor detects that the relative humidity within theenclosure100 is too high, the control system can turn on a fan inside theenclosure100. In certain other embodiments, the control system includes a sensor capable of determining whether an explosion has occurred by detecting a rapid temperature or pressure change. Upon detection of an internal explosion, the sensor communicates the state change to the controller which communicates the state change to a local indicator (not shown) or wirelessly to a remote location. One having ordinary skill in the art will recognize that the control system can be programmed any number of ways to meet specifications of a given area and include any number or type of sensors to determine various states within theenclosure100. In certain embodiments, the control system is controlled wirelessly by a user in a remote location.
• Therefore, the present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to a person having ordinary skill in the art and the benefit of the teachings herein. Having described some exemplary embodiments of the present invention, the use of alternative configurations having heat exchangers in communication with an enclosure is within the purview of those in the art. For example, the heat exchanger system can be positioned on any wall of the enclosure or a portion may be external to the enclosure. Additionally, while the present application discusses a single heat exchanger external to the enclosure, it is understood that a number of other heat exchangers may be used based on the heat transfer properties desired and using the teachings described herein. In addition, the exemplary embodiments of the present invention may be used to actively displace cold air from within the enclosures to the atmosphere. While numerous changes may be made by one having ordinary skill in the art, such changes are encompassed within the scope and spirit of this invention as defined by the appended claims. Furthermore, the details of construction or design herein shown do not limit the invention, other than as described in the claims below. It is therefore evident that the particular exemplary embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present invention. The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.

Claims (22)

1. An enclosure system, comprising:

a housing;

a heat exchanger, the heat exchanger comprising a first heat transfer component in communication with a second heat transfer component, wherein the first heat transfer component is in communication with the inside of the housing, and the second heat transfer component is positioned outside of the housing.

2. The system ofclaim 1, wherein the heat exchanger is selected from the group consisting of thermoelectric coolers, shell and tube heat exchangers, plate heat exchangers, and spiral heat exchangers.

3. The system ofclaim 1, wherein the first heat transfer component is positioned inside the housing.

4. The system ofclaim 1, wherein the first heat transfer component is integrated into a wall of the housing.

5. The system ofclaim 1, wherein the second heat transfer component is coupled to an exterior of the housing.

6. The system ofclaim 1, further comprising equipment positioned within the housing, the equipment to be cooled or heated by the heat exchanger.

7. The system ofclaim 6, wherein the first heat transfer component is coupled to the equipment.

8. The system ofclaim 6, wherein the first heat transfer component is a cooling plate.

9. The system ofclaim 1, wherein the housing is sealed.

10. The system ofclaim 1, further comprising a fan positioned within the housing or externally mounted to the housing.

11. The system ofclaim 10, further comprising a control system coupled to the fan.

12. The system ofclaim 1, further comprising a control system coupled to the heat exchanger.

13. An explosion-proof enclosure system, comprising:

a housing having an internal cavity, the housing being sealed in compliance with hazardous area guidelines;

equipment positioned within the cavity;

a thermally conductive plate positioned within the cavity and proximate to the equipment;

a heat exchanger exterior to the housing;

an inlet tube; and

an outlet tube, wherein the inlet tube and the outlet tube each extend through the housing and connect the heat exchanger to the plate.

14. The system ofclaim 13, wherein the plate comprises an opening therein for receiving a fluid flowing from the inlet tube.

15. The system ofclaim 13, further comprising a fluid flowing from the heat exchanger, through the inlet tube, to an opening within the plate, through the outlet tube, and back to the heat exchanger.

16. The system ofclaim 13, wherein at least one of the inlet or outlet tube is spiral.

17. The system ofclaim 13, wherein the plate comprises multiple plates in communication with each other.

18. The system ofclaim 13, wherein the equipment is to be heated or cooled by the heat exchanger.

19. The system ofclaim 13, wherein the inlet and outlet tubes are sealingly coupled to a wall of the housing.

20. The system ofclaim 13, further comprising a fan positioned within the internal cavity or externally mounted to the housing.

21. The system ofclaim 20, further comprising a control system coupled to the fan.

22. The system ofclaim 13, further comprising a control system coupled to the heat exchanger.

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