FR2503840A1 - CATALYTIC HEATING APPARATUS WITH INCREASED EFFICIENCY - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS A CATALYTIC HEATING APPARATUS INCLUDING A FRAME 11 HAVING SIDE AND REAR WALLS 19; A CATALYTIC BED 15, 16 FIXED TO THE SIDE WALLS AT A CERTAIN DISTANCE FROM THE REAR WALL 19 AND DELIMING A BEDROOM 20 FOR THE HEATING GAS, A GAS DISTRIBUTOR 22 IN THE SAID BEDROOM 20 AND A HEAT REFLECTING DEVICE 25 PLACED BETWEEN THE PART INTERNAL OF THE REAR WALL 19 AND THE CATALYTIC BED 15, 16. THE REFLECTING ELEMENT 25 REDUCES THE TEMPERATURE OF THE EXTERNAL PART OF THE REAR WALL 19 AND INCREASES THE TEMPERATURE OUTSIDE OF THE CATALYTIC BED COMPARED TO CONVENTIONAL APPLIANCES. APPLICATION AS A HEATING APPLIANCE, FOR EXAMPLE IN WORKSHOPS, GARAGES OR ANIMAL ENCLOSURES.

Description

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  The present invention relates to catalytic heaters of the type disclosed and generally described in the United States Patent

  No. 3,037,554. These appliances burn gas under a

  low) such as propane and methane which are surface oxidized at temperatures below the combustion temperature of the gas when used in a flame-producing heater. The prior art, an example of which is given by US Pat. No. 3,037,054, includes catalytic heaters which are increasingly used, particularly in industrial uses. For example, they heat goods trucks to prevent their contents from freezing in cold environments. In addition, catalytic heaters can be used to heat humans in outdoor applications,

  for example when a worker works in

  truck tire change, garages-

service stations and the like.

  An important application that is developing more and more catalytic heaters is the raising of pigs. It is shown that a sow that has had young can crush a large part

  of his reach involuntarily in the enclosure of the piglets.

  Using a directed catalytic heater

  on a portion of the floor, the piglets, after the

  will crawl to the warm floor. Thus they will be able to sleep and rest away from the sow, and when the sow moves from time to time, the likelihood of her squeezing out is greatly reduced. The heating of these suckling pigs promotes rapid growth and makes them able to quickly leave the enclosure of their birth to gain a safer place at a less advanced age. The use of catalytic heating promotes safety in the enclosure of the

  where there is straw and other fuels.

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  Catalytic heaters are also

  used to heat chick brooders.

  Considering the desirability of directing the heat of catalytic heaters to people, animals and objects, it is important to maximize the unidirectional circulation of heat because the heat dissipated at the back of the apparatus serves little or not at all because these catalytic devices 1o are rarely used in a closed chamber type environment. Radiant heat is not basically unidirectional. Radiation from the combustion process tends to move in all directions from the source. In the conventional catalytic heater, the insulating effect of the substrate material reduces radiation from the

  combustion process towards the back of the device.

  Nevertheless, a portion passes through the isolation provided by the catalytic bed substrate towards the rear, and heats the rear portion of the heater frame that directs heat from the rear section of the apparatus. . The present invention

  is intended to reduce the amount of heat

  catalytic heating coil that passes through the back of the device and not in the desired direction, in the direction

of the target of the device.

  The present invention is based on the discovery that a substantial amount of backward radiation loss from a catalytic heater can be reduced by providing a radiation reflective surface between the rear portion of the back of the frame and the rear portion of the catalytic bed. . Reflective surface

  is a polished front side of the back of the chassis, or an over-

  independent reflecting surface placed between the catalytic bed and the back of the chassis. If desired,

  fiberglass or an insulating material of an equivalent type

  slow are placed between the reflective surface and

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  the back of the chassis. When implementing the method

  of the present invention which makes it possible to provide an

  reflective side between the back of the chassis and the back

  catalytic bed, the reflective devices reduce the

  feel the temperature of the outer part of the back and increase the temperature outside the catalytic bed. A comparison made between a similar type of device

  catalytic heating system which does not have a reflective surface

  the heat shows a definite reduction in the temperature

  on the back of the chassis while keeping power

  analog thermal with the same device.

  The main object of the present invention is to produce a reflective surface near the

  rear of the back of the chassis of a heating appliance

  lytic to reduce heat loss through the back of the device, and reflect heat through

  the catalytic bed and forward on the intentional target-

radiated heat.

  Another object of the present invention is

  to increase the efficiency of a heating appliance

  lytic by directing most of the heat

  radiated through the front part.

  Yet another object of the present invention is to provide a device and to provide a method for improving the radiation characteristics of

  catalytic heaters normally manufactured

  without the need for significant machining to

make the change.

  Another object of the present invention is to

  to provide a cost-effective device for reducing radiation

  heat from the back of a catalytic heater in such a way that the price of the change is recovered in a relatively short period of time, thus offsetting the additional costs

  modest involved in the production of such a device.

  Other objects and advantages of the present invention

  will appear more clearly in the description

  following of an embodiment of this

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  invention which is given by way of illustration and not limitation, on the basis of the appended drawing in which - Figure 1 shows schematically the front part of a catalytic heater; FIG. 2 is a partially schematic enlarged cross-sectional view along section line 2-2 of FIG. 1; and FIG. 3 is a rear view of the heating apparatus of FIG. 1 which shows schematically the temperature measurement points making it possible to demonstrate the difference between the prior art and the method of the present invention applied to the apparatus

catalytic heating.

  Fig. 1 shows a typical catalytic heater 10 in which a frame 11 surrounds and fixes a mount 12 which, in turn, forms the outer face of a heating bed 15 which is shown in greater detail in Fig. 2. The bed heater comprises a catalyst 16 on the outer face and a fiber back

  18. It is usual that this is useful with the present

  In this way, the catalyst portion 16 of the heating bed 15 is impregnated with a small proportion of platinum. The fiber backing or substrate is an insulator of the mineral type which is sufficiently permeable to low pressure gases

  to be able to distribute the fuel on the catalytic side

16 of the heating bed 15.

  The filling chamber 20 is in turn supplied with low pressure gas via the inlet 21 and then by a manifold 22 comprising

  24. The safety

  meture and control systems to ignite initial-

  The catalytic heater is well known in the art, and particularly exemplary is U.S. Patent No. 3,037,554. Therefore, these elements are not shown in detail. described in the present application, especially since the present invention can be used with a wide variety of control elements and

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  distribution systems as well as with different teams

start-up and shutdown.

  A reflector 25 is provided between the back of the frame 19 and the heating bed 15. In the preferred embodiment, the reflector is a very strong aluminum foil or plate such as that used in barbecues and for cooking. This aluminum foil has a highly polished surface on one side and

  in contrast, the other side is a little dull. The upper face

  The polished element is oriented so as to be directly opposite to the catalytic heating bed 15. A different embodiment of the reflector is provided when the frame 11 is aluminum: it is the internal rear face which is polished. Other frames may be coated with a reflective surface but the cost of polishing the aluminum or surface coating is normally greater than providing an aluminum foil on the inner portion of the back of the frame 19 as shown here. Optionally, regardless of the type of reflector used, insulation of glass fibers or other equivalent insulating material is placed between the reflective surface 25 and the rear of the frame

  19. In one form of commercialization, results of

  improved states were obtained using a filling

  fiberglass with a thickness of 6.35 mm.

  In such catalytic heaters, a bed of glass fibers is normally placed.

  or comparable nonwoven material behind the catalyst

  16 and directly against the gas distribution element, such as the manifold 22 shown here by way of example. There is then a space behind the gas distribution element or collector. In one of the proposed embodiments, the reflective surface of aluminum is coated with a fiberglass mat 26 having a thickness of 3.2 to 6.55 mm and attached to the rear bowl 19 of the frame 11. L The thickness of the reflector 25 does not play a major role in the reflection, except that the reflector must be thick enough to

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  reflective surface structure. It also seeks the presence of a gap between the outer edges of the reflector 25 and the side of the rear frame 11 to prevent heat loss by conduction, which further enhances the reflectivity to the target area. In an example of concrete realization, a catalytic heater of the type 12.66 MJ supplied by a French company, Société Lyonnaise des Applications Catalytiques, was installed using aluminum foil and glass fiber insulation. a thickness of 6.359m. After the temperatures stabilized, two separate thermometers were independently placed in nine different temperature measurement locations (Tl-T9). Taking two separate thermometers averages the errors of each of the thermometers. By employing nine measurement locations, an average of the back temperature of the catalytic heater could be fairly well established.

  The device was then tested but in its commercial form.

  original without any reflective surface as described above. The basic results were that the average back temperature of the apparatus without use of the process of the present invention, in an average room temperature of 21 ° C, after 120 minutes

  heating, was an average temperature of 81aC.

  With the reflector and a 6.35 mm fiberglass insulation, the average temperature at the back of the frame 11 was 730C. When 6.35 mm glass fiber insulation was not used, the average temperature of

  the rear rose slightly but the temperature reduction

  obtained from the standard heater

  the unmodified 12.66 MJ dart was still at least 5.550C. In the following table, the temperature measurements were reported at measurement points T1-T9, first for the prior art heater and then for the modified heater according to FIG.

present invention.

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BOARD

  Average ambient temperature 21 C minutes of heating

REAR VIEW

  French standard element of 12.66 MJ / h (no reflector) T1

 C-T-1

78 C-T-2

  Total temperature High temperature Low temperature

Average temperature

Average

: 8740C

: 89 C

72 C

: 81 oC 79 C T4

84 C-T-1

82 C-T-2

Myenne 83 C T7

 C-T-1

88 C-T-2

  Average 89 C French standard element of 12.66 MJ / h with reflector and insulation of 6.35 mm in T1 fiberglass 73 C-T-1

69 C-T-2

  Average 71 C Total temperature: High temperature: Low temperature: Temperature nmoy .: 797 C 78 C 64 C 71 C T4

72 C-T-1

 C-T-2

Average 71 C

Different temperature

  average income 81oC - 73 C- = 8 C T7

790C-T-1

76 0C-T-2

Average 77.5 C T2

73 C-T-1

 C-T-2

71.5 C

T5

81 C-T-1

78 C-T-2

79.5 C

T8

88 C-T-1

83 C-T-2

, 50C T2

66 C-T-1

62 C-T-2

64 C T5

69 C-T-1

68 C-T-2

68.5 C

T3

79 C-T-1

76 C-T-2

77.5 C

T6

82 C-T-1

79 0C-T-2

, 5 C T9

870C-T-1

84 C-T-2

, 5'C T3

77 C-T-1

74 C-T-2

, 5 C T6

77 C-T-1

74 C-T-2

, 5 C T8

77 C-T-1

73 C-T-2

 C T9

78 C-T-1

77 C-T-2

77.5 C

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  When the same heater having a reflective surface but not having glass fibers was tested, the average temperature was 750C, which gives a temperature difference with the non-reflective heater 60C. In each example,

  the reflector was an aluminum foil.

  To further confirm these results, tests were conducted with a conventional potentiometer of the type "Simpson 389-3-L". One of the drivers measured the ambient temperature while the other two drivers were connected to flat black sensors

  suspended precisely under each of the two types of

  heating elements, one being the classic element and

  the other being an element representing the present invention

  tion. The classical apparatus had a rise in temperature

  the 19,550C, taken at the front, but the apparatus having a reflective surface according to the present invention had an increase of 22,090C, which corresponds approximately to an increase of 13%. If we apply

  data in the table above and subtract the temperature

  ambient temperature, it is noted that the temperature difference of 80C corresponds to a reduction of approximately

  back radiation. This is related to the increase in

  13% of the frontal radiation mentioned above.

  It should not be overlooked that the use of

  of a heating appliance involving the

  process and the apparatus elements of the present invention.

  It does not require additional training because it uses the same controls, the same equipment and the same sources of gas as for

  unmodified catalytic heating of the prior art.

  The only modification necessary for this user of the heater is to calculate the reduction

  the capacity of the device required for an application

  given because of the higher efficiency of the

  radiation from the front of the device

than towards the target.

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  Although some forms of

  The present invention is not limited to the details indicated, but on the contrary all modifications of equivalent nature are included.

in the present invention.

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Claims (10)

  Catalytic heating apparatus, characterized in that it comprises a frame (11) having side walls and a rear wall (19), a catalytic bed (15, 16) attached to the side walls at a distance from the wall back. (19) and defining a filler chamber (20) between the walls, a gas distribution device (22) in said chamber (20), and a heat reflecting device (25) located between the inner portion of the chamber the rear wall (19) and the catalytic bed (15, 16), the heat reflecting device (25) reducing the temperature of the portion   outer wall (19) and increasing the temperature   outside the catalytic bed (15, 16) compared to a catalytic heater of the same type that does not have the heat reflecting device. 2. Heating apparatus according to claim 1, characterized in that the reflecting device (25) is constituted by the polished inner surface of said wall rear (19).   Heating apparatus according to claim 1, characterized in that the heat reflecting device (25) is a separate element lying between the   inner part of the rear wall (19) and the bed lytic (15, 16).   4. Heating apparatus according to claim 1, characterized in that the heat-reflecting device (25) consists of aluminum foil   whose polished face is opposed to the catalytic bed (15, 16).   5. Heating apparatus according to any one   claims 3 or 4, characterized in that   insulating layer is placed between the reflecting device   heat (25) and the inner surface of the wall rear (19).   6. Process for increasing thermal radiation   as a front end of a catalytic heater, comprising a frame with sidewalls and a bed 2503 84?   catalytic converter attached to the side walls and defining a filling chamber between the rear wall and the catalytic bed, and a device for distributing gas inside said chamber, characterized in that a heat-reflecting surface is introduced between the rear wall of the chassis and the catalytic bed, such that more heat is radiated from the front portion of the catalytic bed of the back of the rear wall of the chassis, compared with the same catalytic heater having not   such a surface reflecting heat.   7. Process according to claim 6, characterized in that an independent element having a surface reflecting heat.   8. Method according to claim 7, characterized   in that an insulating layer is introduced between the   reflective side and the inner part of the wall rear of the chassis.   9. Process according to claim 8, characterized   in that an aluminum foil is chosen to constitute   kill the surface reflecting heat,   10. A method according to any of the claims   cations 7, 8 or 9, characterized in that an insulating layer is chosen which is placed between the heat reflecting surface and the inner portion of the rear wall of the frame, said layer being made of glass fibers.