HK1120595A - Heater - Google Patents

Description

Heating device

The present invention relates to a heater in which a combustible substance is combusted to release heat. More particularly, the present invention relates to radiant heaters for heating industrial buildings such as factories, warehouses, airports, and other large structures.

It is known to heat large buildings, particularly large industrial premises, by means of radiant heaters, and a typical radiant heater used for this purpose consists of a U-shaped pipe radiator system, a burner such as a gas burner connected to one end of the pipe, and a fan arranged at the other end of the pipe for drawing combustion gases from the pipe. The U-shaped pipe is suspended below a heat reflective housing, which reflects radiation emitted from the pipe towards the ground. Such heaters are disclosed, for example, in british patent application GB 2145218.

The main problems encountered with such radiant heaters are ensuring that the radiant flux density at the ground is as uniform as possible and avoiding hot and cold spots. This presents a problem because while a particular form of radiant heater can be configured to provide excellent heating within a building of one size and shape, it can provide a far from ideal heating effect when used in buildings of different sizes and shapes. In particular, it has proven difficult to compensate for variations in the above-ground installation height, which generally depends on the effectiveness of the support structure, such as a roof support structure, on which the heater is mounted.

The applicant's earlier patent US6138662 discloses a modular heating element comprising a basic heater unit to which a reflective skirt of any reflector configuration can be attached. The disclosed heater system has proven successful in improving existing heaters to increase their output and overall efficiency.

The present invention therefore relates to an improved heater unit.

In a first aspect, the present invention provides a radiant heater comprising a radiant heating element; a housing having a lower side recessed to receive a radiant heating element, the radiant heating element being disposed below the housing such that an upper half thereof is entirely within the recess and at least a portion of a lower half thereof projects downwardly from the recess; the recess having a heat reflecting surface for reflecting heat radiation from the radiant heating element in a downward direction; and a heat deflecting member located between the heating element and the reflective surface of the housing so as to prevent heat emitted from the heating element from directly reaching the reflective surface.

Preferably, the heat deflecting member is provided at least partially along the length of the heating element.

Preferably, there are also two or more adjacent heat deflecting members extending at least partially along the length of the heating element.

Preferably, the heat deflecting member is attached to a bracket secured to the top surface of the heating element.

Preferably, the heat deflecting member extends above and to each side of the heating element.

Preferably, the housing further comprises a top cover suspended above the reflective surface.

Preferably, no insulation is provided between the top cover and the reflective surface.

An embodiment of the invention is now shown by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a heater unit constructed according to an embodiment of the invention;

FIG. 2 is the view of FIG. 1 showing the bracket component;

FIG. 3 is the view of FIG. 1 showing the reflector component;

FIG. 4 is the view of FIG. 1 showing the top cover;

FIG. 5 is a perspective view from above of the burner tube of FIG. 1; and

fig. 6 is the view of fig. 1 showing the deflector member.

Referring first to fig. 1, a radiant heater includes two burner tubes 10, 12, generally indicated at 14, located within a housing. The housing 14 includes a reflector member 16, a deflector member 18, and a top cover member 20.

The bracket members 22 are provided at spaced apart (e.g., 1 meter) intervals along the housing 14. Such a bracket member 22 is shown in fig. 2.

The stand member 22 includes a lower stand 24 having a generally horizontal cross-bar portion 26 formed of box section steel and a generally upright member 28 secured thereto by bolts (not shown). A short transverse mounting 32 of box section steel is secured by welding at the mid-point of the cross-bar section 30.

The upper bracket 34 has an outer wall 36 and an inner wall 38. The outer wall 36 is formed so as to have a generally horizontal region 40 and downwardly diverging portions 42 and 44. The ends of the branch portions 42, 44 of the upper bracket 34 are secured to the upright member 28 of the lower bracket 24.

The inner wall 38 of the upper bracket 34 is shaped to have first and second horizontal regions 46, 48 separated by a downwardly converging member 50, the distal end of the downwardly converging member 50 being secured to the steel box section 32 of the lower bracket 24.

The reflector element 16 is shown in fig. 3. The reflector member 16 comprises an aluminium plate which follows the contour of the inner wall 38 of the upper bracket 34. The reflector 16 is connected to the inner wall of the upright member 22 of the lower bracket and the top surface of the box section 32 via nuts and bolts or similar mechanisms.

The reflector 16, once mounted as part of the housing 10, thus defines two downwardly open sub-channels 52, 54 each having an upper reflective surface 52a, 54a and a downwardly diverging lateral reflective surface 52b, 52c, 54b, 54 c. The surfaces 52c and 54c are coupled together via a coupling wall 56, which coupling wall 56 is bolted to the top surface of the box-section 32.

The top cover member 20 is shown in FIG. 4. The shroud 20 comprises a mild steel plate having a generally horizontal region 58 extending to downwardly diverging portions 60, 62. The cover 20 is bolted to the outer wall 36 of the upper support 34 so as to project approximately 1.5 to 2.5cm above the reflector 16. No insulation is provided between the cover 20 and the reflector 16. Thus, the temperature of the combustion air entering the burner is increased by absorbing additional heat from the entire top surface of the reflector 16, which in turn substantially increases the flame temperature. This has the effect of significantly increasing the output of the heater (approximately 10 to 15%) and thereby increasing the efficiency and overall performance of the system, since the overall radiant heat output of the heater is proportional to the overall temperature of the conduits 10, 12 within the system.

Referring now to fig. 5, the burner tubes 10, 12 extend along passages 52, 54 from one end of the housing 14 to the other. The duct 10 is connected at one end to a gas burner 64 which heats the interior of the duct 10. Combustion gases are drawn from the burner 64 along the duct 10 and into the return duct 12 via a U-bend (not shown) by an extraction fan (not shown) mounted at one end.

The pipes 10, 12 are made of steel or the like and may be surface treated in order to maximise their radiant efficiency. In use, the pipe 10 is heated by the gas burner 64 and then acts as a radiator heating element. The pipe 12 also gives radiation, but to a lesser extent since it is somewhat cooler than the pipe 10.

In current systems, the heater operates at a higher temperature than can typically be expected in similar systems such as those described in the applicant's prior patents. About 1.5m from the burner 64 creates a hot spot along the pipe 10 within about 1m of the distance, typically in excess of 640 ℃. The heat emitted at this hot spot will generally cause damage and distortion of the aluminium reflector 16 above the pipe 10 in this region, particularly when the heater system is operating for a long period of time.

To prevent such deformation, the housing 14 includes a deflector member 18 located above the pipe 10, the pipe 10 extending along the length of the hot spot region.

The deflector member 18 is best shown in fig. 6. Here, it can be seen that a "T-shaped" mounting bracket 66 is secured to the top side of the duct 10 so as to extend upwardly therefrom. Several mounting brackets 66 are located at spaced intervals along the pipe in the hot spot region to allow the stainless steel deflector 18 to extend along the pipe 10 across the hot spot region. As can be seen in fig. 5, the deflector 18 comprises two adjacent stainless steel heat-dissipative shaped panels, each about 2.2m in length.

The deflector 18 serves to absorb and dissipate the radiant heat emitted from the pipe 10, particularly its top surface, above the hot spot region, so as to deflect the radiant heat from the reflector 16 in this region, thereby preventing intense heat from reaching the reflector 16 directly. The deflector 18 is shaped so as to have a generally horizontal top surface 68 (so as to cover the top surface of the duct 10) and two branched downwardly extending surfaces (so as to cover the side surfaces of the duct 10), thereby preventing intense radiant heat from reaching directly the adjacent cooler duct 12 and reflector coupling wall 56.

It has been found that the presence of the deflector member 18 increases the overall efficiency of the heating system while preventing damage and deformation of portions of the housing 14.

The pipes 10, 12 are supported within the housing by pipe support cables as described in detail in applicant's earlier US patent No.6138662, which is incorporated herein by reference.

It will be apparent that numerous modifications and substitutions may be made to the radiant heater illustrated in the drawings and described above without departing from the principles of the present invention, and all such modifications and substitutions are intended to be covered by this application.

Claims (7)

1. A radiant heater comprising a radiant heating element; a housing having a lower side recessed to receive a radiant heating element, the radiant heating element being disposed below the housing such that an upper half thereof is entirely within the recess and at least a portion of a lower half thereof projects downwardly from the recess; the recess having a heat reflecting surface for reflecting heat radiation from the radiant heating element in a downward direction; and a heat deflecting member located between the heating element and the reflective surface of the housing so as to prevent heat emitted from the heating element from directly reaching the reflective surface.

2. A radiant heater according to claim 1, wherein the heat deflecting member is disposed at least partially along the length of the heating element.

3. A radiant heater according to claim 1 or 2, wherein two or more adjacent heat deflecting members extend at least partially along the length of the heating element.

4. A radiant heater according to claim 3, wherein the one or more heat deflecting members are attached to a bracket secured to the top surface of the heating element.

5. A radiant heater according to claim 3 or 4, wherein the one or more heat deflecting members extend above and to each side of the heating element.

6. A radiant heater according to any preceding claim, wherein the housing further comprises a top cover suspended above the reflective surface.

7. A radiant heater according to any preceding claim, wherein no insulation is provided between the top cover and the reflective surface.