Claims:We claim:
1. A hybrid thermal insulation (100) for reducing heat loss and avoiding corrosion of steel, the thermal insulation (100 comprising:
a first insulation layer (2) comprising a silica aerogel provided on hot base surface (1);
a second insulation layer (3) comprising Low Resin Bond (LRB) mineral wool provided on the first insulation layer (2); and
a third insulation layer (4) comprising the silica aerogel provided on the second insulation layer (3) to avoid entry of moisture into the LRB mineral wool of the second insulation layer (3).

2. The hybrid thermal insulation (100) as claimed in the claim 1, wherein a thickness of the second insulation layer (3) is greater than a thickness of the first insulation layer (1).

3. The hybrid thermal insulation (100) as claimed in the claim 1, wherein a thickness of the second insulation layer (3) is greater than a thickness of the third insulation layer (4).

4. The hybrid thermal insulation (100) as claimed in the claim 1, wherein the thermal insulation (100) further comprising an outer aluminum cladding sheet (5) provided on the third insulation layer (4).

5. The hybrid thermal insulation (100) as claimed in the claim 1, wherein ratio of thickness of the first insulation layer (2), the second insulation layer (3), and the third insulation layer (4) is in the range 1:4:1 to 1:16:1 depending on the application.
6. The hybrid thermal insulation (100) as claimed in the claim 1, wherein fixing components of the first insulation layer (2), the second insulation layer (3), and the third insulation layer (4) are selected from conventional mineral wool insulation with reduced sizes and weight.
, Description:HYBRID THERMAL INSULATION FOR HOT SURFACES
FILED OF INVENTION:
[001] The present subject matter described herein relates to thermal insulation for flat and cylindrical surfaces. More particularly the present invention relates to a method of laying hybrid thermal insulation comprising of conventional low cost Low Resin Bonded (LRB) mineral wool sandwiched by high cost low thermal conductivity silica aerogel.
BACKGROUND OF INVENTION:
[002] Conventionally Low Resin Bonded (LRB) mineral wool is used for providing thermal insulation application for hot surfaces of industrial and domestic equipment and pipelines. This mineral insulation involves huge thickness of insulation to achieve the required human contact surface temperature acceptable to OHSAS standard. Also, it is hazardous to the personnel handling the material and for the environment. Generally, this Low Resin Bonded (LRB) mineral wool when subjected to temperature above 300 °C, loses its resin character and consequently, it will lead to the formation of insulation sag in the horizontal pipeline or fall of mineral wool in the case of vertical pipeline leading to heat loss.
[003] Due to the moisture absorbing characteristics, Low Resin Bonded (LRB) wool leads to corrosion of the contacting steel surface. The hydrophobic silica aerogel is having good potential for overcoming the problems of Low Resin Bonded (LRB) mineral wool but is highly expensive. Hence, a hybrid method of laying silica aerogel and mineral wool sandwich thermal insulation is proposed to overcome the problems of mineral wool insulation as explained above and also to optimise the thickness of thermal insulation for substantial cost saving in laying the hybrid insulation in thermal power plants.
[004] Therefore, there is need in the art to provide a hybrid thermal insulation which reduces the heat loss and avoid corrosion of steel surface. Further, thickness of the thermal insulation is also a major technical issues which need to be resolved.
OBJECT OF THE INVENTION:
[005] An object of the present invention is develop to build a hybrid thermal insulation to reduce thickness of insulation and heat loss and to avoid corrosion of steel surfaces.
[006] A still another objective of the invention is to provide a method of laying hybrid thermal insulation for hot flat and cylindrical surface.
[007] Yet another object of the present invention is to provide a hybrid thermal insulation comprising of conventional low cost Low Resin Bonded (LRB) mineral wool sandwiched by high cost low thermal conductivity silica aerogel.
[008] Yet another object of the present invention is to provide a hybrid thermal insulation with low thickness and less cost.
SUMMARY OF INVENTION:
[009] The present subject matter relates to a hybrid thermal insulation for hot surfaces. The hybrid thermal insulation is a combination of mineral wool and silica aerogel arranged in such a manner where bottom most layer in contact with the hot surface and the top most layer in contact with the cladding sheet will be of low thickness silica aerogel and the conventional mineral insulation is kept in-between. This hybrid thermal insulation having the first inner layer of silica aerogel over surface will avoid the corrosion caused by mineral wool resulting in increase of service life of the steel surface. The second outer layer of silica aerogel placed above the mineral wool avoids entry of moisture content into the mineral wool. The second insulation layer of the silica aerogel guards the mineral wool in getting wet and hence avoids sag formation. For the same heat duty, the overall thickness of hybrid insulation is less than that of complete mineral wool insulation in the prior insulations. Also, the hybrid insulation is less expensive than complete silica aerogel insulation.
[0010] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWING:
[0011] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0012] FIGURE-1: illustrates laying of hybrid thermal insulation on flat surface, in accordance with an embodiment of the present subject matter; and
[0013] FIGURE-2: illustrates laying of hybrid thermal insulation on cylindrical surface, in accordance with an embodiment of the present subject matter;
[0014] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT:
[0015] The present subject matter relates to a hybrid thermal insulation for hot surfaces. The hybrid thermal insulation is a combination of mineral wool and silica aerogel arranged in such a manner where bottom most layer in contact with the hot surface and the top most layer in contact with the cladding sheet will be of low thickness silica aerogel and the conventional mineral insulation is kept in-between. This hybrid thermal insulation having the first inner layer of silica aerogel over surface will avoid the corrosion caused by mineral wool resulting in increase of service life of the steel surface. The second outer layer of silica aerogel placed above the mineral wool avoids entry of moisture content into the mineral wool. The second insulation layer of the silica aerogel guards the mineral wool in getting wet and hence avoids sag formation. For the same heat duty, the overall thickness of hybrid insulation is less than that of complete mineral wool insulation in the prior insulations. Also, the hybrid insulation is less expensive than complete silica aerogel insulation.
[0016] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0017] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0018] Fig. 1 shows the construction of hybrid thermal insulation for flat surfaces requiring thermal insulation. In the present construction, a hot base flat plate 1 which is to be thermally insulated. A first insulation layer 2 of silica aerogel of optimized thickness is provided on the hot base flat plate 1. Wherein thickness of the first insulation layer 2 can be optimized as per requirements. Further a third insulation layer 3 comprising Low Resin Bonded (LRB) mineral wool of adequate thickness is provided over the first insulation layer 1 of silica aerogel. At the end, third insulation layer 4 which is outer layer of silica aerogel of optimized thickness is put atop the mineral wool second insulation layer 3 and immediately below the outer aluminium cladding sheet 5. The fixing and supporting components for this hybrid thermal insulation are same for conventional mineral wool insulation like channels, angles, fixing pin, binding wire, retainer, casing support, cladding sheet, and fixing screws.
[0019] Fig. 2 shows the construction of hybrid insulation for cylindrical surfaces requiring thermal insulation. The hot base cylindrical surface 6 which is to be thermally insulated. A first insulation layer 7 of silica aerogel of optimized thickness followed by second insulation layer 8 of Low Resin Bonded (LRB) mineral wool of adequate thickness is applied over the first insulation layer 7 of silica aerogel. Outer layer of the silica aerogel second insulation layer 9 of optimized thickness is put atop the mineral wool insulation layer 8 and immediately below the outer aluminium cladding sheet 10. The fixing and supporting components for this hybrid insulation will be as that for conventional mineral wool insulation.
[0020] The hybrid thermal insulation is such a way that the ratios of thickness of the first insulation layer (2, 7) the second insulation layer (3,8), and the third insulation layer (4,9) are in the range of 1:4:1 to 1:16:1 depending on the application.
[0021] In another embodiment of the present subject matter, The hybrid method of providing thermal insulation for hot flat and cylindrical surfaces which is a combination of mineral wool and silica aerogel arranged such that the bottom most layer in contact with the hot surface and the top most layer in contact with the cladding sheet will be of low thickness silica aerogel with the conventional mineral insulation of adequate thickness in-between.
[0022] The inner layer of silica aerogel of the hybrid thermal insulation protects the material of the hot flat / cylindrical surface from corrosion.
[0023] The outside layer of silica aerogel of the hybrid thermal insulation avoids the entry of moisture into mineral wool insulation from atmosphere avoiding major heat loss due to moisture entrapment.
[0024] The hybrid thermal insulation protects the mineral wool at service temperatures above 300 °C from losing its resin character and sagging.
[0025] The hybrid thermal insulation lowers the overall thickness of insulation leading to lower outer surface area for cylinders which in-turn reduces heat loss than conventional mineral wool insulation for the same heat duty. The hybrid thermal insulation results in reduction in overall thickness of insulation leading to lower outer surface area for cylinders which in-turn reduces heat loss than conventional mineral wool insulation for the same heat duty.
[0026] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.