Apparatus and method for temperature regulation of ceiling heaters

Abstract

The present application relates to a heating device for installation in a ceiling. The heating device includes a housing, a heating element mounted on a portion of the housing, a temperature sensor for detecting the temperature of the housing, and a fan located within the housing for generating airflow through the housing to dissipate heat. The fan can be turned on when the temperature detected by the temperature sensor reaches a predetermined threshold.

Description

[Technical Field]

[0001] This application relates to heating devices, and more particularly to heating devices for installation within ceilings.

[0002] An embodiment of the present invention provides a heating apparatus adapted for mounting within a ceiling having a temperature control means, however, it will be appreciated that the present invention may be applicable in a broader context and for other applications. [Background technology]

[0003] Heating systems in homes are typically installed either on the ground, in walls, or in ceilings. In the latter case, it is desirable for aesthetic and other reasons to install the heating system at least partially within the ceiling cavity. However, heat accumulation within the ceiling cavity can pose a fire hazard, which can pose safety concerns for heat distribution.

[0004] Any discussion of background art in this specification should not be taken as an admission that such art is widely known or forms part of the common general knowledge in the field. Summary of the Invention [Means for solving the problem]

[0005] According to one aspect of the present invention there is provided a heating apparatus for mounting in a ceiling, the heating apparatus comprising: The housing and a heating element attached to a portion of the housing; a temperature sensor for detecting the temperature of the housing; a fan located within the enclosure for generating airflow through the enclosure to dissipate heat; Including, The fan is turned on when the temperature detected by the temperature sensor reaches a predetermined threshold.

[0006] Typically, the heating device may be configured to be mounted within the ceiling such that the underside of the heating element is generally flush with the ceiling, and the heating element may be fixedly attached to the housing and remain in place during operation.

[0007] Advantageously, the heating device can be mounted within the ceiling, providing a minimalist appearance by creating a simple and uncluttered ceiling space. The heating device provides effective heat dissipation away from the heating element through the operation of a temperature sensor and fan. The heat dissipation provided by the heating device has been found to be sufficient so that it is not necessary to move the heating device outside the ceiling cavity during operation.

[0008] The heating element may be mounted in any suitable location relative to the housing, hi some embodiments, the heating element may be mounted to the base of the housing.

[0009] In some embodiments, the enclosure is configured to be mounted in the space between adjacent ceiling joists of the ceiling.

[0010] In some embodiments, the enclosure further includes an inlet and an outlet for allowing airflow through the enclosure, the inlet and the outlet being located near opposite ends of the enclosure, respectively. Notably, the inlet and the outlet may be defined in the base of the enclosure to establish airflow communication between the enclosure and the heated space below the ceiling. In other embodiments, the inlet and the outlet may be located in any suitable location. In some embodiments, the enclosure may include a single outlet for directing airflow from the enclosure. For example, airflow from the ceiling cavity may be directed into the enclosure through a gap between the enclosure walls, and the airflow may be directed from the enclosure to the space below the ceiling through the outlet. In this case, a fan may be located above the heating element to direct airflow from the ceiling cavity into the enclosure and out through the outlet. The outlet may be located at either end of the enclosure or below the heating element on the base of the enclosure.

[0011] In some embodiments, a temperature sensor is located within the housing distal to the fan.

[0012] In some embodiments, the housing has an elongated body having an inlet end and an outlet end, the inlet defined in the inlet end of the body and the outlet defined in the outlet end of the body, the fan mounted within the housing proximate the inlet end, the temperature sensor mounted external to the body of the housing proximate the outlet end, and the heating element mounted to a base of the housing between the fan and the temperature sensor.

[0013] In some embodiments, the housing has a sloped portion adjacent the outlet.

[0014] In some embodiments, the temperature sensor is mounted externally to the housing on an angled portion of the housing.

[0015] In some embodiments, the temperature sensor is provided by a thermal switch, which may be configured to turn on the fan when a temperature sensed by the thermal switch reaches a predetermined upper threshold.

[0016] In some embodiments, the thermal switch is configured to turn off the fan when a temperature sensed by the thermal switch reaches a predetermined lower threshold.

[0017] In some embodiments, the fan continues to operate after the heating element is turned off until the temperature sensed by the temperature sensor reaches the predetermined lower threshold.

[0018] In some embodiments, the thermal switch is an automatic reset thermal switch.

[0019] In some embodiments, the heating element is adapted to turn off when the temperature of the enclosure reaches a predetermined maximum threshold.

[0020] In some embodiments, the heating apparatus further includes a failsafe switch configured to turn off the heating element when the temperature detected by the failsafe switch reaches the predetermined maximum threshold.

[0021] In some embodiments, the heating apparatus further includes a power source, and the failsafe switch is configured to turn off the heating element by a supply disconnect relay to disconnect the heating element from the power source when the temperature detected by the failsafe switch reaches the predetermined maximum threshold.

[0022] In some embodiments, the power supply and the heating element are connected in parallel. In particular, the heating element may be connected in parallel to the fan and the temperature sensor. The heating device may advantageously include a heating module and a temperature control module. The heating module may include the heating element and a fail-safe switch for turning off the heating element when a predetermined maximum temperature threshold is reached. The temperature control module may include a fan and a thermal switch for operating the fan, as described above. The heating module and the temperature control module may each be connected in parallel to the power supply so that operation of the temperature control module is not affected by operational errors associated with the heating module, and vice versa.

[0023] In some embodiments, the power supply, the failsafe switch, and the supply disconnect relay are mounted in a terminal box external to the housing, which is advantageous because electrical components housed in a terminal box external to the housing can be protected from high temperatures of the housing.

[0024] In some embodiments, the fail-safe switch is a manually reset thermal switch.

[0025] In some embodiments, the fan is mounted within the housing adjacent one end of the housing such that the terminal box is located adjacent an inlet side of the fan.

[0026] In some embodiments, the fan is mounted within the housing adjacent one end thereof such that the terminal box is located adjacent the inlet side of the fan. Operation of the fan is advantageous because it typically cools the end of the housing adjacent the terminal box more quickly than the remainder of the housing. This helps cool the terminal box and prevent overheating of the electrical components therein. [Brief explanation of the drawings]

[0027] Illustrative embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a perspective view of a heating device according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded view of the heating device shown in FIG. [Figure 3] FIG. 3 is a side view of the heating device shown in FIG. [Figure 4] FIG. 4 is a perspective view of a heating device installed in a ceiling cavity according to an embodiment of the present invention. [Figure 5] FIG. 5 is a schematic diagram of the circuitry associated with the heating device shown in FIG. [Figure 6] FIG. 6 is a flow diagram illustrating the operation of the circuit of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 1 shows a perspective view of a housing 102 of a heating apparatus 100 for mounting within a ceiling according to one embodiment of the present invention. The housing 102 can be made from a variety of materials, including galvanized steel, aluminum, or stainless steel, as some examples. The material from which the housing is made is preferably corrosion- and fire-resistant, given its intended location within a ceiling. In the illustrated embodiment, the housing 102 has an elongated body because the heating apparatus 100 is configured to fit between ceiling joists 400 within a ceiling cavity 402, as illustrated in FIG. 4. The housing 102 can take a variety of different shapes within a typical roof installation, with a rectangular or elongated shape being preferred for mounting within the space between adjacent ceiling joists 400 within a ceiling.

[0029] Referring to FIG. 2 , an exploded view of the heating device 100 is shown. The heating device 100 includes a housing 102, a base of which has a heating element 104 attached. The heating device 100 further includes a temperature sensor 106 located outside the housing 102. In some embodiments, the housing 102 may define an opening. A temperature sensing element of the temperature sensor 106 may be aligned with, received by, or pass through the opening so that the sensing element is in communication with the airflow within the housing 102, allowing the temperature sensor 106 to more easily detect the temperature within the housing 102. In the illustrated embodiment, the temperature sensor 106 is connected to a terminal box 110 via an electrical connection 105. The electrical connection is located outside the housing 102. In this configuration, the electrical connection 105 is provided outside the housing 102, reducing the risk of the electrical connection 105 overheating during operation of the heating element 104.

[0030] The heating device 100 includes a fan 108 adapted to turn on when the temperature within the housing 102, as detected by a temperature sensor 106, reaches a predetermined upper threshold. The fan 108 is mounted to one end of the housing 102 adjacent to a terminal box 110. As shown more clearly in FIG. 2 , the fan 108 is attached to the terminal box 110 and can be installed within the housing 102 as a single unit during assembly. The terminal box 110 is mounted to the exterior of the housing 102.

[0031] 2, terminal box 110 houses electrical components including a failsafe switch 107 provided by a manual thermal switch, a supply disconnect relay 506, and a transformer 504. The failsafe switch 107 is configured to operate to turn off the heating element 104 by way of the relay 506 for disconnecting the heating element 104 from the power supply 502 when the temperature detected by the failsafe switch 107 reaches a predetermined maximum threshold. The transformer 504 steps down the power from the mains supply. The terminal box 110 further provides terminals 112, 114, 116 for connection to an AC power input, connecting the power input to the user control panel 109 and connecting the power output to the heating element 104.

[0032] In fact, heating apparatus 100 is configured to be installed and operate within a roof cavity 402, as more clearly illustrated in Figure 4. As can be seen in Figure 4, heating apparatus 100 is configured to be mounted between ceiling joists 400 within ceiling cavity 402. Heating apparatus 100 may be secured to ceiling joists 400 by a variety of fastening means, such as screws, nails, or bolts (not shown), which penetrate ceiling joists 400 and provide a secure means for attaching heating apparatus 100 to ceiling joists 400.

[0033] In one embodiment, the housing 102 is mounted between ceiling joists 400 such that the bottom surface 118 of the housing 102 is flush with the ceiling panel 404. In this embodiment, an opening may be provided in the ceiling panel 404, and the bottom surface 118 of the housing 102 may be received in the opening such that the bottom surface 118 is exposed to the space below the ceiling panel 404. In another embodiment, the housing 102 may be completely hidden behind the ceiling panel 404. In this embodiment, the bottom surface 118 may be located in close proximity to the ceiling panel 404 such that heat from the device 100 radiates through the ceiling panel to the space below the ceiling.

[0034] 3, the heating apparatus 100 may include an inlet 300 and an outlet 302. The inlet 300 and outlet 302 are located at either end of the heating element 104. The inlet and outlet (300, 302) provide a means of airflow throughout the heating apparatus 100 to assist in regulating the temperature within the heating apparatus 100. The location of the inlet 300 and outlet 302 at either end of the heating element 104 allows for longitudinal airflow along the length of the heating element 104. The longitudinal airflow associated with the heating element 104 provides convective heat transfer via the flow of air proximate the heating element 104.

[0035] Additionally, the location of the inlet 300 and outlet 302 generally along the underside 118 of the heating element 104 allows excess heat from the enclosure 102 to be redirected downward from the ceiling cavity into the space below the ceiling, thereby providing more efficient heating to the space below the ceiling.

[0036] 1-3, the temperature sensor 106 is located distally from the fan 108. Locating the temperature sensor 106 distally from the fan 108 reduces the likelihood of rapid temperature fluctuations in the vicinity of the temperature sensor 106, which could result in undesirable frequent on / off switching of the fan 108. It also prevents the fan 108 from switching on prematurely because temperature gradients vary within the enclosure, with the temperature in the vicinity of the fan 108 generally being cooler than the temperature elsewhere within the enclosure 102.

[0037] As can be seen in FIGS. 1-3 , in the illustrated embodiment, the housing 102 includes a sloped portion 103 near the outlet 302. Notably, the sloped portion is located at one end of the housing 102 opposite the terminal box 110. The temperature sensor 106 can be mounted on the sloped portion 103 outside the housing 102 without increasing the overall height of the housing 102. For example, if the temperature sensor 106 were located at the top of the housing 102, the height of the housing 102 would increase, which may often be limited within a ceiling cavity. By locating the temperature sensor 106 on the sloped portion 103 of the housing 102, the height of the housing 102 is not affected by the location of the temperature sensor 106. As best illustrated in the embodiment shown in FIG. 3 , the sloped portion 103 is located near the outlet 302, providing the additional benefit of more effectively directing airflow downward toward the outlet 302.

[0038] It will be appreciated that the height within the ceiling cavity 402 may be limited, and any reduction in the height of the heating apparatus 100 may be significant to the installation of the heating apparatus 100 within the ceiling cavity 402. In some embodiments, the temperature sensor 106 is provided by a thermal switch configured to operate to turn on the fan 108 when the temperature reaches a predetermined upper threshold. Similarly, the thermal switch is configured to operate to turn off when the sensed temperature reaches a predetermined lower threshold.

[0039] The thermal switch can take many forms, including a bimetallic device in which a bimetallic strip is used to open and close the switch based on temperature fluctuations. Alternatively, an electronic temperature thermal switch can be used to provide greater accuracy in calibrating the switching temperature. Preferably, the thermal switch is an automatic thermal reset switch in which the thermal switch automatically self-resets (i.e., disconnects the fan 108 from the power source) if the sensed temperature falls below a predetermined lower threshold.

[0040] As an additional safety feature, heating apparatus 100 also includes a failsafe switch 107 adapted to turn off heating element 104 if a predetermined maximum temperature threshold is reached within enclosure 102. This failsafe switch 107 is intended to act as an override in the event of failure of other switching mechanisms within heating apparatus 100. For example, if fan 108 fails and the temperature of enclosure 102 exceeds the maximum temperature threshold, failsafe switch 107 can be triggered to turn off heating element 104 via supply disconnect relay 506.

[0041] Referring now to FIG. 5, a circuit diagram 500 illustrating the circuit configuration of the heating device 100 is shown.

[0042] As can be seen in Figure 5, circuit 500 consists of two main circuits operating in parallel. The two main circuits include a low voltage circuit for operating fan 108 (temperature control module) and a high voltage circuit for providing a controllable power output 111 to heating element 104 via user control panel 109 (heating module). Both circuits are powered by AC mains power supply 502. The output voltage of power supply 502 is converted to a suitable operating voltage via step-down transformer 504.

[0043] In the heating module 602, stepped-down power via a transformer 504 is coupled in parallel across a failsafe switch 107 (thermal switch) and a relay 506. During normal operation, the failsafe switch 107 is closed and a coil within the relay 506 is energized such that the relay 506 is also closed, providing power to the heating element 104. When the temperature sensed by the failsafe switch 107 exceeds a maximum threshold (e.g., 80°C), the failsafe switch 107 opens and de-energizes the relay 506, thereby opening the relay 506 and disconnecting the heating element 104 from the power supply 502. The relay 506 can be used to switch a high-current circuit associated with the heating element 104. A user control panel 109 allows a user to turn the heating element 104 on and off via a user interface (not shown) and adjust the amount of current supplied to the heating element 104 to adjust the temperature of the heating element 104. Among other things, a user control panel 109 can be used to control the power output 111 to the heating element 104, whereby the current supplied to the heating element 104 can be adjusted by the user. The user interface can include buttons and / or a wireless communication module for receiving wireless control signals from a remote controller (not shown).

[0044] The failsafe switch 107 may include a manual thermal reset (MTR) switch that can be calibrated to disconnect the heating element 104 if the heating element 104 reaches an upper threshold temperature. The MTR switch may be located in various locations within the housing 102 to sense the internal temperature of the housing 102. In the illustrated embodiment, the MTR is located in the terminal box 110.

[0045] In other embodiments, the relay 506 may be avoided by using a failsafe switch 107 with a sufficiently high current rating to reliably switch the current supplied to the heating element 104 .

[0046] In the temperature control module 604, stepped-down power via the transformer 504 is coupled in parallel across the temperature sensor 106 and the fan 108. The temperature sensor 106 is provided by a thermal switch that controls the on / off operation of the fan 108 based on calibrated upper and lower temperature thresholds. In one embodiment, the thermal switch 106 is configured to turn the fan 108 on when the detected temperature reaches an upper threshold (e.g., 60°C) and turn the fan 108 off when the detected temperature reaches a lower threshold (e.g., 45°C). In some embodiments, the temperature sensor 106 may take various forms, including a resistance temperature detector (RTD), a thermocouple, or a thermistor.

[0047] 5, the heating module and temperature control module are connected in parallel to the power supply 502 to enable their independent operation. In this manner, the failsafe switch 107 is operable to shut off the heating element 104 in the event of a failure of the fan 108 and / or temperature sensor 106. Similarly, the fan 108 may continue to operate even after the heating element 104 has been turned off, for example, if the temperature within the enclosure 102 remains above the lower temperature threshold of the sensor 106 due to thermal inertia.

[0048] In an alternative configuration, the heating device 100 may be configured to operate to adjust the speed of the fan 108 within a predetermined range based on the temperature sensed by the temperature sensor 106. As a fail-safe measure of operation, the heating device 100 may be adapted to monitor the fan 108, and if the fan 108 fails, power to the heating element 104 may be cut off to avoid a situation in which the heating element 104 operates without thermal control of the fan 108.

[0049] In some embodiments, the transformer 504 may be omitted from the circuit configuration 500 and electrical components compatible with the mains power supply (eg, 240V) may be used.

[0050] As mentioned above, heating device 100 is configured so that fan 108 continues to operate for a predetermined period of time after heating element 104 is turned off. This provides the advantage of reducing the effects of thermal inertia, which could cause the heat within enclosure 102 to exceed certain upper thermal limits of electrical components and cables within enclosure 102 if fan 108 and heating element 104 were turned off simultaneously. By continuing to operate fan 108 after heating element 104 is turned off, additional cooling is provided via airflow along heating element 104, reducing the likelihood that thermal inertia will cause the temperature within enclosure 102 to rise to an undesirable level.

[0051] 6 is a flow chart illustrating the independent operation of the heating module 602 and the temperature control module 604 described above with reference to FIG. 5. In the heating module 602, the fail-safe switch 107 encl ), and if the temperature exceeds a maximum temperature of 80°C (Tmax), the failsafe switch 107 is adapted to open the relay 506, thereby cutting off power to the heating element 104. Typically, the failsafe switch 107 is a manual reset switch. For safety reasons, if the failsafe switch 107 is triggered by reaching a maximum temperature threshold, it is desirable for a technician to inspect the heating device 100. For example, the heating device 100 may have been installed incorrectly. In these embodiments, the failsafe switch 107 requires manual reset after being triggered, for example after inspection or maintenance by a technician. In an alternative embodiment, the failsafe switch 107 may be an automatic thermal switch. If the temperature inside the enclosure falls below a threshold (T encl <T max ), the failsafe switch 107 automatically closes, re-energizing the relay 506 and providing power to the heating element 104.

[0052] In step 604 , the user switches on the heating element 104 via the user control panel 109 .

[0053] In query step 606, the temperature in or near the enclosure (T encl ) is the maximum temperature threshold (T max ), the failsafe switch 107 opens and the method proceeds to step 608. Otherwise, the method returns to step 606, the failsafe switch 107 remains closed, and no change is made to the operation of the heating module 602.

[0054] In step 608 , the failsafe switch 107 is opened and the heating element 104 is switched off via the supply disconnect relay 506 .

[0055] In query step 610, the temperature in or near the enclosure (T encl ) is the maximum temperature threshold (T max ), the failsafe switch 107 can be automatically or manually reset. Otherwise, the failsafe switch 107 remains open and the heating element 104 remains disconnected from the power supply 502.

[0056] In the temperature control module 620, the fan 108 is controlled via the thermal switch 106 to regulate the temperature of the enclosure (T encl ) is the upper temperature threshold (T upper ) is compared with

[0057] Temperature inside the enclosure (T encl ) is the upper temperature threshold (T upper ), the thermal switch 106 is closed and the fan 108 is turned on, cooling the inside of the enclosure 102 and therefore reducing the temperature inside the enclosure 102. encl ) is the lower temperature threshold (T lower ) (e.g., 45°C), the fan 108 is turned off or otherwise the temperature reaches a lower temperature threshold (T lower ), at which point the fan 108 is turned off.

[0058] In query step 622, the temperature inside the enclosure (T encl ) is the upper temperature threshold (Tupper ), the thermal switch 106 is closed, the fan 108 is turned on and the method proceeds to step 624. Otherwise, the thermal switch 106 remains open and the fan 108 is turned off.

[0059] In step 624 , the fan 108 is turned on to dissipate heat within the enclosure 102 .

[0060] In query step 626, the temperature inside the enclosure (T encl ) is the lower temperature threshold (T lower ), the thermal switch 106 is automatically reset and the fan 108 is turned off in step 628. Otherwise, the thermal switch 106 remains closed, the fan 108 continues to operate, and the method returns to step 624. After step 628, the method returns to query step 622.

[0061] <Interpretation> References throughout this specification to "one embodiment," "some embodiments," or "embodiments" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one embodiment," "in some embodiments," or "in embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0062] As used herein, unless otherwise specified, the use of ordinal adjectives such as "first," "second," "third," etc. to describe a common object merely indicates that different instances of a similar object are being referred to and does not imply that the objects so described must be in a predetermined order, whether in time, space, ranking, or otherwise.

[0063] In the following claims and the description of this specification, any one of the terms comprising, comprising, or including is an open term meaning to include at least the element / feature that follows it, but not to exclude others. Therefore, when used in a claim, the term comprising should not be interpreted as being limited to the means, elements, or steps that follow it. For example, the scope of an expression "device including A and B" should not be limited to a device consisting only of elements A and B. As used in this specification, any one of the terms comprising, including, or including is also an open term meaning to include at least the element / feature that follows it, but not to exclude others. Therefore, including is synonymous with including and means including.

[0064] In the foregoing description of exemplary embodiments of the present disclosure, it should be understood that various features of the disclosure may be grouped together in a single embodiment, figure, or description for the purpose of streamlining the disclosure and / or facilitating an understanding of one or more of the various inventive aspects. This method of disclosure, however, should not be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present disclosure.

[0065] Furthermore, although some embodiments described herein include some features but not other features included in other embodiments, combinations of features from different embodiments are intended to be within the scope of the disclosure and form different embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments may be used in any combination.

[0066] In the description provided herein, numerous specific details are set forth. However, it will be understood that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0067] Similarly, the term coupled, when used in the claims, should not be interpreted as being limited to only direct connections. The terms "coupled" and "connected," along with their derivatives, may be used. It should be understood that these terms are not intended to be synonyms for each other. Thus, the scope of the phrase device A coupled to device B should not be limited to devices or systems in which the output of device A is directly connected to the input of device B. This means that there is a path between the output of A and the input of B, which may be a path that includes other devices or means. "Coupled" means that two or more elements are in direct physical, electrical, or optical contact, or that two or more elements are not in direct contact with each other, but still cooperate or interact with each other.

[0068] The embodiments described herein are intended to cover any adaptations or variations of the present invention. While the invention has been described and illustrated with reference to specific exemplary embodiments, those skilled in the art will recognize that additional embodiments can be readily envisioned that are within the scope of this invention.

Claims

1. 1. A heating apparatus for mounting in a ceiling, the heating apparatus comprising: The housing and a heating element attached to a portion of the housing; a temperature sensor for detecting the temperature of the housing; a fan located within the enclosure for generating airflow through the enclosure to dissipate heat; Including, The heating device, wherein the fan is turned on when the temperature detected by the temperature sensor reaches a predetermined threshold.

2. The heating apparatus of claim 1 , wherein the enclosure is configured to be mounted in a space between adjacent ceiling joists of the ceiling.

3. 3. The heating device of claim 1, wherein the housing further includes an inlet and an outlet for allowing airflow through the housing, the inlet and the outlet being located adjacent opposite ends of the housing, respectively.

4. 4. The heating device of claim 1, wherein the temperature sensor is located within the housing distal to the fan.

5. 4. The heating device of claim 3, wherein the housing has an elongated body having an inlet end and an outlet end, the inlet being defined in the inlet end of the body and the outlet being defined in the outlet of the body, the fan being mounted within the housing proximate the inlet end, the temperature sensor being mounted on the exterior of the body of the housing proximate the outlet end, and the heating element being mounted to a base of the housing between the fan and the temperature sensor.

6. The heating device of claim 3 , wherein the housing has a sloped portion adjacent the outlet.

7. The heating device according to claim 6 , wherein the temperature sensor is attached to an inclined portion of the housing outside the housing.

8. 8. The heating device of claim 1, wherein the temperature sensor is provided by a thermal switch, the thermal switch being configured to turn on the fan when a temperature sensed by the thermal switch reaches a predetermined upper threshold.

9. 9. The heating apparatus of claim 8, wherein the thermal switch is configured to turn off the fan when a temperature sensed by the thermal switch reaches a predetermined lower threshold.

10. 9. The heating device of claim 1, wherein the fan continues to operate after the heating element is turned off until the temperature sensed by the temperature sensor reaches the predetermined lower threshold.

11. 10. A heating device according to claim 8 or 9, wherein the thermal switch is an automatic reset thermal switch.

12. 12. A heating device according to any one of the preceding claims, wherein the heating element is adapted to be turned off when the temperature of the enclosure reaches a predetermined maximum threshold.

13. 10. The heating apparatus of claim 9, further comprising a failsafe switch configured to turn off the heating element when a temperature detected by the failsafe switch reaches the predetermined maximum threshold.

14. 12. The heating apparatus of claim 11, wherein the heating apparatus further includes a power source, and the failsafe switch is configured to turn off the heating element with a supply disconnect relay to disconnect the heating element from the power source when the temperature detected by the failsafe switch reaches the predetermined maximum threshold.

15. The heating device according to claim 14, wherein the power supply and the heating element are connected in parallel.

16. 16. A heating apparatus as claimed in claim 14 or 15, wherein the power supply, the fail-safe switch and the supply disconnect relay are mounted in a terminal box external to the housing.

17. 17. A heating apparatus as claimed in any one of claims 14 to 16, wherein the fail-safe switch is a manually reset thermal switch.

18. 17. The heating apparatus of claim 16, wherein the fan is mounted within the housing adjacent one end of the housing so that the terminal box is located adjacent an inlet side of the fan.

19. 19. A heating apparatus as claimed in any preceding claim, wherein the heating apparatus is configured to be mounted within the ceiling such that an underside of the heating element is generally flush with the ceiling.

20. 20. A heating device as claimed in any preceding claim, wherein the heating element is fixedly attached to the housing and remains in place during operation.

Images