WO2018207008A1

WO2018207008A1 - Multi-layer heat insulator system

Info

Publication number: WO2018207008A1
Application number: PCT/IB2017/054392
Authority: WO
Inventors: Kush Dinesh RATHI
Original assignee: Rathi Kush Dinesh
Priority date: 2017-05-11
Filing date: 2017-07-20
Publication date: 2018-11-15

Abstract

The present invention relates to a multi-layer, flexible thermal insulator for pipes and tubes and method of application thereof. The innermost layer is a stainless-steel wire mesh (101) and is exposed to the said conduit or tube carrying the heated substances. The outermost layer (104) which is temperature-resistant, anti-corrosion, high strength, durable and with longer life-expectancy is composed of aluminium or graphite or silicone coated fibre glass. The system may comprise additionally a plurality of comprising at least one layer comprising silica fibre (102) and one layer comprising ceramic fibre blanket (103). The thermal insulator also comprises a clamp (106) and guide pocket (105) to lock the layers of the insulator together.

Description

TITLE OF INVENTION

MULTI-LAYER HEAT INSULATOR SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY

[0001] The present application claims priority from provisional patent application no. 201721016618 filed on the 11th day of May 2017.

TECHNICAL FIELD

[0002] The present invention pertains to a heat insulator for preventing loss of heat from a plurality of pipes carrying heated liquid or gaseous materials installed in a plurality of applications including boiler systems, chiller systems, exhaust systems of commercial vehicles, internal combustion engines etc. and method of application thereof.

BACKGROUND

[0003] Insulation systems have played a critical role in the industry over the last many decades. Maintaining temperatures inside carrier pipes or tubes is of crucial importance for a variety of applications like boiler systems, chiller systems, exhaust systems of commercial vehicles, internal combustion engines, furnaces, kilns, chimneys etc.

[0004] For e.g. the importance of maintenance of a particular temperature for the exhaust pipes of the vehicles cannot be undermined. Exhaust gases discharged from the vehicular engines are carcinogenic and pose a serious environmental problem. In developed countries across Europe and United States, regulations regarding exhaust gases have been strengthened and due compliance is mandated. To meet the existing guidelines and norms on emissions i.e. Bharat Stage IV (BS IV) engine norms, particulate matter (PM) discharged from an engine needs to be burned in the exhaust pipe. The system uses either selective catalytic reduction (SCR) after- treatment approach or the exhaust gas recirculation (EGR) approach for achieving the burning of ammonia / urea inside the exhaust pipe and prevent their exposure to the environment. Since this burning is effected at roughly 360 degree Celsius to 380 degree Celsius, the maintenance of temperature of the exhaust pipe becomes crucial and said invention may help comply with the said BS IV emission standards particularly for emissions from trucks, buses etc.

[0005] Many methods of preventing heat loss exist but some of them are expensive, some are inflexible, some are not adaptable to various end-user size requirements while some do not provide adequate thermal protection or insulation. In one prior art, the use of ceramic coatings and insulating sleeves or wraps has been shown. However, they are expensive and require the component to be disassembled from the vehicle. Also, many of these sleeves are not flexible as they are either rigid or require a rigid protective cover. In another prior art, the use of glass fibres has been disclosed. However, glass fibres suffer from poor durability and are easily broken and is unsustainable in the long run.

[0006] Therefore, there is a need for a heat insulator system and method of application thereof to suit the diverse needs of various commercial sectors and yet be a one stop solution to prevent crucial heat loss. Accordingly, the present invention which relates to a heat insulating cover for a plurality of applications including but not limited to cover for exhaust pipes of commercial vehicles, boiler systems, chiller systems, internal combustion engines etc. and which attempts to solve the various problems in the prior art by introducing a multi-layer, flexible and durable alternative to increase the efficiency of the applications, to increase effective insulation and be sustainable by increasing the service life, may solve a long standing pressing need.

[0007] Therefore, in light of the foregoing deficiencies in the prior art, the applicant's invention is herein presented. SUMMARY

[0008] This summary is provided to introduce aspects related to development of heat-resistant, flexible, multi-layer insulator system for a plurality of applications. This summary is however not intended to disclose essential features of the innovation, nor is it intended to determine, limit or restrict. [0009] In accordance with one aspect of the present invention, the features of a multi-layer heat insulator system placed around a conduit, wherein the system may comprise an innermost layer comprising a stainless steel wire mesh, an outermost layer comprising a fabric made of glass fibre coated on both sides either by a polymer with repeating Si-O-Si units or by aluminium or by graphite, and a plurality of intermediate layers comprising at least one layer comprising a silica fabric coated with a hydrous phyllosilicate mineral and at least one layer comprising a ceramic fibre blanket, are disclosed.

[0010] In accordance of with one aspect of the present invention, the features of a multi-layer heat insulator system placed around a conduit, wherein the inner surface of the innermost layer is in contact with the conduit, and wherein the outer surface of the outermost layer is in contact with the atmosphere, and wherein the system has thickness in the range of 6 mm to 15 mm and has a percentage bench ΔΤ value in the range of 57.0 % to 63.7 % for a temperature of up to 1000 degree Celsius inside the conduit, are disclosed [0011] In accordance with one aspect of the present invention, the features of a flexible multi-layer heat insulator system comprising at least four and up to six layers, are disclosed. The multi-layered insulator may comprise an outermost layer of a fabric made from glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite. The outermost layer may be reflective and high temperature resistant. The innermost layer may comprise of a fine support mesh made from stainless steel (SSM). The plurality of intermediate layers in between the outermost layer and SSM may comprise ceramic fibre blanket, vermiculite coated high silica fabric, or any combinations thereof. [0012] In accordance with an exemplary aspect of the present invention, the features of a flexible multi-layer heat insulator system, wherein the outermost layer comprises a double sided silicone coated glass fibre fabric (DSSCGFF), are disclosed. [0013] In accordance with another aspect of the present invention, the features of a multi-layer heat insulator system, wherein the outermost layer may comprise either DSSCGFF or aluminium coated glass cloth or graphite coated glass cloth as per the need and specifications of heat insulations needed, are disclosed.

[0014] In accordance with one aspect of the present invention, the features of a multi-layer heat insulator system, wherein the operating temperature ranges inside the conduit for said insulator with four layers may be -30 degree Celsius to 750 degree Celsius, are disclosed.

[0015] In accordance with another aspect of the present invention, the features of a multi-layer heat insulator system, wherein the operating temperature ranges inside the conduit for said insulator with six layers may be -30 degree Celsius to 1000 degree Celsius, are disclosed.

[0016] In accordance with one aspect of the present invention, the features of a multi-layer heat insulator system, wherein the percentage difference in temperature (% Bench ΔΤ) for said insulator with four layers may be up to 63.7 for insulators wherein outermost layer is made of DSSCGFF, aluminium coated glass cloth and graphite coated glass cloth, are disclosed.

[0017] In accordance with another aspect of the present invention, the features of a multi-layer heat insulator system, wherein the percentage difference in temperature (% Bench ΔΤ) for said insulator with six layers may be up to 76.5% for insulators wherein outermost layer is made of DSSCGFF, aluminium coated glass cloth and graphite coated glass cloth, are disclosed.

[0018] In accordance with one aspect of the present invention, the features of a multi-layer heat insulator system, wherein the thickness for said insulator with four layers or six layers may be in the range of 4 mm to 25 mm and more preferably in the range of 6 mm to 15 mm, are disclosed.

[0019] In accordance with one aspect of the present invention, the features of a multi-layer heat insulator system, wherein the constituent four layers or six layers are assembled with the help of a clamp and a guide pocket provision in the outermost layer of the invention, are disclosed.

[0020] In accordance with one aspect of the present invention, the features of a multi-layer heat insulator system, wherein the system is placed around a conduit containing heated gaseous or liquid substances, and wherein the conduit may have a thickness in the range of 1.5mm to 1.7mm, are disclosed.

[0021] In accordance with one aspect of the present invention, the features of a multi-layer heat insulator, wherein said insulator can be used in a plurality of applications including but not limited to boiler system, solar system, chiller system, genset, vehicular exhaust systems, buses, automobiles, engine cover, etc., are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The detailed description is given with reference to the accompanying figure.

In the figure, 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 drawings to refer like features and components.

[0023] Figure la and lb illustrate cross- sectional views of the arrangement of layers of the system (100) for heat insulator with four layers.

[0024] The figure depicts embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the steps illustrated herein may be employed without departing from the principles of the disclosure described herein. DETAILED DESCRIPTION

[0025] The foregoing detailed description of embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, there are shown in the present document example constructions of the disclosure; however, the disclosure is not limited to the specific design disclosed in the document and the drawings.

[0026] The detailed description is provided 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 drawings to refer like features and components. [0027] Referring figure 1, an embodiment of the present invention, which may comprise a multilayer flexible heat insulator system for placing around a conduit for a plurality of applications, is described. The heat insulator may comprise a body having an innermost layer (101) made up of stainless steel, an outermost layer (104) comprising a fabric made up of glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite and having a means of attachment comprising a clamp (106) and a guide pocket (105) and a plurality of intermediate layers comprising at least one layer of high silica content coated with a hydrous phyllosilicate mineral (102) and at least one layer of a ceramic fibre blanket (103). In another embodiment (not shown in figure) of the preferred invention, multilayer flexible heat insulator system may comprise innermost layer made up of stainless steel, an outermost layer comprising a fabric made up of glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite and having a means of attachment comprising a clamp (106) and a guide pocket (105) and a plurality of intermediate layers comprising at least one layer silica fibre glass cloth coated with a hydrous phyllosilicate mineral, at least one layer comprising a fabric made up of glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite and at least one layer of a ceramic fibre blanket. The aim of these layers is to reduce heat transfer (via conduction, convection and radiation) to and from the conduit carrying the heated substance to which the heat insulator is attached. This benefits the overall efficiency and performance of the system.

[0028] In one preferred embodiment of the present invention, the multilayer flexible heat insulator system may comprise four layers and may be placed around the conduit such that the inner surface of the innermost layer (101) of the system is in contact with the outer skin of the conduit, and wherein the outer surface of the outermost layer (104) of the system is in contact with the atmosphere. The system may comprise a plurality of intermediate layers, wherein at least one intermediate layer may comprise of a silica fibre glass cloth (102) with coating by a phyllosilicate hydrous mineral. The said silica fibre glass cloth may be placed upon the innermost layer such that the outer surface of the innermost layer (101) of the system is in contact with the inner surface of the silica fibre glass cloth (102). The system may further comprise at least one other intermediate layer which may be comprised of ceramic fibre blanket (103). The said ceramic fibre blanket may be placed upon the silica fibre glass cloth (102) such that the inner surface of the ceramic fibre blanket (103) is in direct contact with the outer surface of the silica fibre glass cloth layer

(102) . The system may comprise a final outermost layer (104) comprising a fabric made up of glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite. The said outermost layer (104) may be placed on the ceramic fibre blanket (103) such that the inner surface of the outermost layer is in contact with the outer surface of the ceramic fibre blanket

(103) and the outer surface of the outermost layer (!04) is exposed to the atmosphere.

[0029] In another preferred embodiment of the present invention, the multilayer flexible heat insulator system may comprise six layers and may be placed around the conduit such that the inner surface of the innermost layer (101) of the system is in contact with the outer skin of the conduit, and wherein the outer surface of the outermost layer (104) of the system is in contact with the atmosphere. The system may comprise a plurality of intermediate layers, wherein at least one intermediate layer may comprise of a silica fibre glass cloth (102) with coating by a phyllosilicate hydrous mineral. The said silica fibre glass cloth (102) may be placed upon the innermost layer (101) such that the outer surface of the innermost layer (101) of the system is in contact with the inner surface of the silica fibre glass cloth (102). The system may further comprise at least one other intermediate layer which may be comprised of ceramic fibre blanket (103). The said ceramic fibre blanket (103) may be placed upon the silica fibre glass cloth (102) such that the inner surface of the ceramic fibre blanket (103) is in direct contact with the outer surface of the silica fibre glass cloth layer (102). The system may comprise at least one other intermediate layer (104) comprising a fabric made up of glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite. The said intermediate layer may be placed on the ceramic fibre blanket (103) such that the inner surface of said intermediate layer (104) is in contact with the outer surface of the ceramic fibre blanket (104). The system may further comprise at least one other intermediate layer which may be comprised of a second ceramic fibre blanket (103). The said second ceramic fibre blanket (103) may be placed on the layer comprising a fabric made up of glass fibre (104) such that the inner surface of the second ceramic blanket (103) is in contact with the outer surface of the intermediate layer (104) comprising a fabric made up of glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite. The system may comprise a final sixth outermost layer (104) comprising a second layer of a fabric made up of glass fibre and coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite. The said second layer (104) of a fabric made up of glass fibre may be placed upon the second ceramic fibre blanket (103) such that the inner surface of the second outermost layer (104) of a fabric made up of glass fibre is in contact with the outer surface of the second ceramic fibre blanket (103) and wherein the outer surface of the second outermost layer (104) of a fabric made up of glass fibre coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite is exposed to the atmosphere. 30] In one embodiment of the present invention, the innermost layer of the heat insulator (101) may comprise a knitted wire mesh like structure. The mesh like structure may be obtained from a substance capable of withstanding extensive heat since it is the first element of the heat insulator to have direct contact with the heated surface of the conduit carrying heated substances. The mesh is designed in a way to cover maximum surface area of the surface of the conduit carrying heated substance with or without any bends, curves, junctions. The wire mesh serves an important function of avoiding contact between the surface of the pipe carrying heated substance and the fabric layers of the heat insulator and hence tensile strength and thickness of the wire mesh are important parameters to be considered to avoid loss of heat from the pipe carrying heated substance to the environment. [0031] In another embodiment of the present invention, the innermost layer (101) of the heat insulator may comprise of a fibre glass mesh.

[0032] In a preferred embodiment of the present invention, the innermost layer (101) of the heat insulator may comprise of a knitted stainless- steel wire mesh of grade 304 with a diameter in the range of 0.25 mm to 0.4 mm, thickness in the range of 0.25mm and 0.3 mm, tensile strength in the range of 600 mega pascals to 800 mega pascals at 30% to 55% elongation and yield stress in the range of 280 mega pascals to 380 mega pascals.

[0033] In one embodiment of the present invention, the second layer (102) of the heat insulator may comprise fabric made from silica fiberglass cloth. The said fibreglass cloth may be obtained from a substance known to withstand extreme temperatures for over a long period of time. The fiberglass cloth may comprise of materials able to withstand continuous temperatures of 1000 degree Celsius for long periods of time, and instantaneous temperatures of up to 1600 degree Celsius. The said fabric may be coated by a mineral with a natural laminar structure that can help material expand or unfold upon exposure to extreme heat. The mineral coated fibreglass directly contacts the stainless-steel wire mesh and hence tensile strength, thermal conductivity and thickness of the layer are important parameters to be considered to avoid loss of heat from the pipe carrying heated substance to the environment. [0034] In another embodiment of the present invention the second layer (102) of the heat insulator may comprise of high silica.

[0035] In a preferred embodiment of the present invention, the second layer of the heat insulator may comprise of vermiculite coated silica fibre cloth with thickness in the range of 0.6 mm to 1.5 mm and tensile strength in the range of 217 lbs / inch to 320 lbs / inch following the EN ISO 13934.1 testing standard.

[0036] In one embodiment of the present invention, the third layer (103) of the heat insulator may comprise a fabric primarily made from alumina- silica and which has high temperature stability, low thermal conductivity, low heat storage, excellent thermal shock resistance, light weight, and superior corrosion resistance exhibiting thermal stability even at temperatures up to 1430°C (2600°F). The third layer (103) plays a crucial role in acoustic insulation as well as thermal insulation and hence tensile strength, thermal conductivity and thickness of the layer are important parameters to be considered to avoid loss of heat from the pipe carrying heated substance to the environment.

[0037] In a preferred embodiment of the present invention, the third layer (103) of the heat insulator may comprise of ceramic fibre blanket with thermal conductivity for a layer with 128 grade density in the range of 0.11 watts per meter-kelvin to 0.15 watts per meter-kelvin in the temperature range of 400 degree Celsius to 600 degree Celsius with a thickness in the range of 6 mm and 20 mm, tensile strength in the range of 2500 kgf/m3 to 7500 kgf/m3 for an applied load in the range of 64 kg /m3 to 190 kg / m3 respectively for 128 grade density product.

[0038] In one embodiment of the present invention, the outermost layer (104) of the heat insulator may comprise a fibreglass fabric which is coated with a material to render it temperature-resistant, anti-corrosive, high strength, durable and with longer life-expectancy. The external coating can increase resistance to most chemicals and oil and sealing property and since the layer is exposed to environment, it should possess necessary wear resistance to avoid degradation and hence tensile strength, thermal conductivity and thickness of the layer are important parameters to be considered to avoid loss of heat from the pipe carrying heated substance to the environment.

[0039] In a preferred embodiment of the present invention, the outermost layer (104) of the heat insulator may comprise double-sided silicone coated glass fibre or aluminium coated glass cloth or graphite coated glass cloth with thickness in the range of 0.4 mm to 0.8 mm.

[0040] In one embodiment of the present invention, the heat insulator may comprise six layers wherein the heat insulator may comprise of the third layer (103) i.e. the ceramic fibre blanket more than once and of the outermost layer (104) i.e. double-sided silicone coated glass fibre or aluminium coated glass cloth or graphite coated glass cloth may occur in the assembled product more than once to form the fourth and / or fifth layer of the invention respectively.

[0041] In one embodiment of the present invention, the heat insulator may be obtained from materials that are flexible and hence is able to readily adapt to a variety of cross-sectional sizes and shapes, in addition to changes in direction along the conduit length.

[0042] In one embodiment of the present invention, the heat insulator may be provided with a tightening clamp (106) and a pocket (105) thereof for affixing all the layers of the invention together. [0043] In one embodiment of the present invention, the heat insulator may comprise of four layers or six layers which may be attached to one another through various methods including but not limited to spinning, woven, non-woven, fixed, glued, high temperature adhesive, stitching, or mechanical fasteners any combination thereof. [0044] In an exemplary embodiment of the present invention, the heat insulator may comprise of a guide pocket (105) in the outermost layer (104) of the invention. The guide pocket (105) serves as a locking and holding mechanism while assembling all the layers of the invention together. This allows the invention to retain the flexible nature of the product while providing a solid locking system for effective functioning of the heat insulator. A clamp (106) is provided for said locking purpose and the clamp (106) is fitted into the guide pocket (105) for effective assembly of the heat insulator and the invention comprises use of polytetrafluoroethylene thread for stitching the insulator at a temperature of 550 degree.

[0045] In one embodiment of the present invention, the operating temperature of the four -layered heat insulator may range from -30 degree Celsius to 750 degree Celsius for insulators wherein outermost layer (104) is comprised of a fabric made up of glass fibre coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite. Alternatively, the operating temperature of the six-layered heat insulator may range from -30 degree Celsius to 1000 degree Celsius for insulators wherein outermost layer (104) is comprised of fabric made up of glass fibre coated on both sides by either a polymer with repeating Si-O-Si units or by aluminium or by graphite. [0046] In accordance with one exemplary embodiment of the present invention, the difference in temperature (% Bench ΔΤ) for the four-layered heat insulator may be up to 63.7%, for insulators wherein outermost layer (104) is comprised of DSSCGFF, aluminium coated glass cloth and graphite coated glass cloth. Alternatively, in accordance with another exemplary embodiment of the present invention, the difference in temperature (% Bench ΔΤ) for the six-layered insulator may be up to 76.5%, for insulators wherein outermost layer (104) is comprised of DSSCGFF, aluminium coated glass cloth and graphite coated glass cloth. The bench level difference in temperature (ΔΤ) is calculated in the as described in the standard tests as provided in IS 3144: 1992, IS 9489: 1980, IS 9490: 1980 and IS 3446: 1980.

[0047] In one embodiment of the present invention, the thickness of the heat four layered heat insulator or the six-layered heat insulator may be in the range of 4 mm to 25 mm and more preferably in the range of 6 mm to 15 mm for insulators wherein outermost layer is (104) made of DSSCGFF, aluminium coated glass cloth or graphite coated glass cloth. [0048] In one embodiment of the present invention, the multi-layered flexible heat insulator may be tested for susceptibility to flammability, high -temperature durability and thermal shock and low -temperature durability and thermal shock as well as for resistance against water and resistance against mud. [0049] In one embodiment of the present invention, the multi-layered flexible heat insulator may be tested for resistance to flammability as per standard procedures in IS 3144: 1992. The method may comprise using the multi layered flexible system, either in its entire or as system divided into various parts of predetermined dimensions such that each part may comprise a wholesome representation of the entire material and wherein the test may be carried out with any one part of the system. The method may comprise testing the multi layered flexible system or part thereof with predetermined dimensions by exposure to direct heat in a heating system which may most preferably comprise of a furnace capable of achieving a temperature of at least 800 degrees Celsius. The testing method may be carried out in a manner such that the multi layered flexible system is exposed to the direct heat in an inside - out fashion wherein the innermost layer comprising stainless steel wire mesh is exposed to direct heat.

[0050] In an exemplary embodiment of the present invention, the multi-layered flexible heat insulator of a predetermined length and with a thickness of 8 mm, upon exposure to direct heat on its innermost layer (101) comprising stainless steel wire mesh, does not catch fire even after exposure to a temperature in the range of 700 degree Celsius to 900 degree Celsius and more specifically at a temperature of 800 degrees Celsius for a time period of 5 minutes according to the standard procedures outlined in IS 3144:1992. [0051] In one embodiment of the present invention, the multi-layered flexible heat insulator may be tested for evaluating the difference of temperature between the temperature of the outer skin / skin surface exposed - to - environment of the heating element (Tl) and the temperature of the outermost layer of the heat insulator system (T2). The testing procedure may comprise use of a part of the multi-layered flexible heat insulator system with predetermined dimensions and applying the insulator system on a heating element wherein the innermost layer (101) of the system comprising the stainless-steel wire mesh is in direct contact with the heating element. Further, the insulator system may be adequately locked / clamped using the clamp (106) and guide pocket (105) to lock the layers of the insulator together so as to ensure that heat is not lost to the environment during the testing procedure. The testing procedure may comprise heating the heating element initially to a temperature of 350 degrees Celsius through passage of heated substance in any chemical state whether, liquid or gaseous, and holding the heating element at 350 degrees Celsius for a period of at least 15 minutes and may further comprise noting the temperature of the outer skin / skin surface exposed - to - environment of the heating element (Tl) and the temperature of the outermost layer of the heat insulator system (T2) and calculating the difference in temperature (Bench ΔΤ ) between temperature of the outer skin / skin surface exposed - to - environment of the heating element (Tl) and the temperature of the outermost layer of the heat insulator system (T2). The calculated value of Bench ΔΤ may be alternatively expressed in terms of percentage equivalents. This temperature reveals capacity of the heat insulator system to capture the heat within its multi-layered structure and prevent loss of heat to the environment. The said process may be repeated at by increasing the temperature of the heating element at recording the Bench ΔΤ at predetermined temperature intervals, preferably wherein the temperature testing points are separated from each other by a difference of at least 50 degrees Celsius. 52] In an exemplary embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with a predetermined length and 8 mm thickness when tested for Bench level Delta Temperature measurement, may provide a Bench ΔΤ of 196 degrees Celsius (% Bench ΔΤ - 58.5 %) at 350 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 274 degrees Celsius (% Bench ΔΤ - 62.4 %) at 450 degrees Celsius temperature inside heating element, may provide Bench ΔΤ of 320 degrees Celsius (% Bench ΔΤ - 59.8 %) at 550 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 376 degrees Celsius (% Bench ΔΤ - 59.1 %) at 650 degrees Celsius temperature inside heating element and may provide a Bench ΔΤ of 440 degrees Celsius (% Bench ΔΤ - 60.1 %) at 750 degrees Celsius temperature inside heating element.

[0053] In one embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with predetermined dimensions may be tested for resistance to water wherein the test may comprise evaluating structural integrity of the material and the Bench ΔΤ values at increasing temperature intervals between 350 degrees Celsius to 750 degrees Celsius and wherein the test may comprise initially soaking the insulator system or part thereof with predetermined dimensions in water for at least 100 hours. Further the testing process may comprise use of a part of the multi-layered flexible heat insulator system with predetermined dimensions and applying the insulator system on a heating element wherein the innermost layer of the system comprising the stainless-steel wire mesh is in direct contact with the heating element and insulator system may be adequately locked / clamped using the clamp and guide pocket to lock the layers of the insulator together so as to ensure that heat is not lost to the environment during the testing procedure. The testing procedure for evaluating Bench ΔΤ and % Bench ΔΤ as illustrated above may be followed. Briefly, the initial temperature inside the heating element may be 350 degrees Celsius which may be kept constant for 15 mins followed by noting the temperature of the outer skin / skin surface exposed - to - environment of the heating element (Tl) and the temperature of the outermost layer of the heat insulator system (T2) and calculating the difference in temperature (Bench ΔΤ). Further, the temperature may be increased up to 750 degrees Celsius with 15 min holding at every 50 degrees Celsius along with noting Tl and T2 for calculating Bench ΔΤ and % Bench ΔΤ at 400, 450, 500, 550, 600, 650, 700 and 750 degrees Celsius.

[0054] In an exemplary embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with a predetermined length and 8 mm thickness when tested for resistance to water may reveal no structural failure (i.e. may comprehensively pass the water resistance test) and further may provide a Bench ΔΤ of 187 degrees Celsius (% Bench ΔΤ - 57 %) at 350 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 274 degrees Celsius (% Bench ΔΤ - 63 %) at 450 degrees Celsius temperature inside heating element, may provide Bench ΔΤ of 305 degrees Celsius (% Bench ΔΤ - 60.4 %) at 550 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 363 degrees Celsius (% Bench ΔΤ - 60 %) at 650 degrees Celsius temperature inside heating element and may provide a Bench ΔΤ of 419 degrees Celsius (% Bench ΔΤ - 59.4 %) at 750 degrees Celsius temperature inside heating element. 55] In one embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with predetermined dimensions may be tested for resistance to mud wherein the test may comprise evaluating structural integrity of the material and the Bench ΔΤ values at increasing temperature intervals between 350 degrees Celsius to 750 degrees Celsius and wherein the test may comprise applying mud to the insulator system or part thereof with predetermined dimensions for at least 100 hours. Further the testing process may comprise use of a part of the multi-layered flexible heat insulator system with predetermined dimensions and applying the insulator system on a heating element wherein the innermost layer (101) of the system comprising the stainless-steel wire mesh is in direct contact with the heating element and insulator system may be adequately locked / clamped using the clamp (106) and guide pocket (105) to lock the layers of the insulator together so as to ensure that heat is not lost to the environment during the testing procedure. The testing procedure for evaluating Bench ΔΤ and % Bench ΔΤ as illustrated above may be followed. Briefly, the initial temperature inside the heating element may be 350 degrees Celsius which may be kept constant for 15 mins followed by noting the temperature of the outer skin / skin surface exposed - to - environment of the heating element (Tl) and the temperature of the outermost layer of the heat insulator system (T2) and calculating the difference in temperature (Bench ΔΤ). Further, the temperature may be increased up to 750 degrees Celsius with 15 min holding at every 50 degrees Celsius along with noting Tl and T2 for calculating Bench ΔΤ and % Bench ΔΤ at 400, 450, 500, 550, 600, 650, 700 and 750 degrees Celsius. [0056] In an exemplary embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with a predetermined length and 8 mm thickness when tested for resistance to mud may reveal no structural failure (i.e. may comprehensively pass the mud resistance test) and further may provide a Bench ΔΤ of 188 degrees Celsius (% Bench ΔΤ - 57 %) at 350 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 267 degrees Celsius (% Bench ΔΤ - 62.2 %) at 450 degrees Celsius temperature inside heating element, may provide Bench ΔΤ of 325 degrees Celsius (% Bench ΔΤ - 60.2 %) at 550 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 384 degrees Celsius (% Bench ΔΤ - 60 %) at 650 degrees Celsius temperature inside heating element and may provide a Bench ΔΤ of 460 degrees Celsius (% Bench ΔΤ - 62.1 %) at 750 degrees Celsius temperature inside heating element.

[0057] In an embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with predetermined dimensions may be tested for high temperature thermal durability and thermal shock resistance wherein the test may comprise evaluating structural integrity of the material and the Bench ΔΤ values at increasing temperature intervals between 350 degrees Celsius to 750 degrees Celsius and wherein the test may comprise heating the insulator system or part thereof with predetermined dimensions initially at 750 degrees Celsius for 400 hours with 20 seconds of water quenching at a time interval of every one hour and further testing the insulator system for evaluating Bench ΔΤ and % Bench ΔΤ as illustrated in aforementioned embodiments. Briefly, the initial temperature inside the heating element may be 350 degrees Celsius which may be kept constant for 15 mins followed by noting the temperature of the outer skin / skin surface exposed - to - environment of the heating element (Tl) and the temperature of the outermost layer of the heat insulator system (T2) and calculating the difference in temperature (Bench ΔΤ). Further, the temperature may be increased up to 750 degrees Celsius with 15 min holding at every 50 degrees Celsius along with noting Tl and T2 for calculating Bench ΔΤ and % Bench ΔΤ at 400, 450, 500, 550, 600, 650, 700 and 750 degrees Celsius. [0058] In an exemplary embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with a predetermined length and 8 mm thickness when tested for high temperature durability and thermal shock resistance may provide a Bench ΔΤ of 195 degrees Celsius (% Bench ΔΤ - 58.2 %) at 350 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 268 degrees Celsius (% Bench ΔΤ - 62 %) at 450 degrees Celsius temperature inside heating element, may provide Bench ΔΤ of 335 degrees Celsius (% Bench ΔΤ - 62.6 %) at 550 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 404 degrees Celsius (% Bench ΔΤ - 62.8 %) at 650 degrees Celsius temperature inside heating element and may provide a Bench ΔΤ of 462 degrees Celsius (% Bench ΔΤ - 62.8 %) at 750 degrees Celsius temperature inside heating element.

[0059] In an embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with predetermined dimensions may be tested for low temperature thermal durability and thermal shock resistance wherein the test may comprise evaluating structural integrity of the material and the Bench ΔΤ values at increasing temperature intervals between 350 degrees Celsius to 750 degrees Celsius and wherein the test may comprise heating the insulator system or part thereof with predetermined dimensions initially at 750 degrees Celsius for 15 min followed by exposing insulator system or part thereof with predetermined dimensions at a temperature of -40 degrees Celsius and finally placing the insulator system or part thereof with predetermined dimensions in a hot chamber at 200 degrees Celsius for 5 min. This entire cycle may be repeated for at least 200 times to check the low temperature thermal durability and thermal shock resistance of the system. The process may further comprise testing the insulator system for evaluating Bench ΔΤ and % Bench ΔΤ as illustrated in aforementioned embodiments. Briefly, the initial temperature inside the heating element may be 350 degrees Celsius which may be kept constant for 15 mins followed by noting the temperature of the outer skin / skin surface exposed - to - environment of the heating element (T 1 ) and the temperature of the outermost layer of the heat insulator system (T2) and calculating the difference in temperature (Bench ΔΤ). Further, the temperature may be increased up to 750 degrees Celsius with 15 min holding at every 50 degrees Celsius along with noting Tl and T2 for calculating Bench ΔΤ and % Bench ΔΤ at 400, 450, 500, 550, 600, 650, 700 and 750 degrees Celsius.

[0060] In an exemplary embodiment of the present invention, the multi-layered flexible heat insulator system or part thereof with a predetermined length and 8 mm thickness when tested for low temperature thermal durability and thermal shock resistance may provide a Bench ΔΤ of 197 degrees Celsius (% Bench ΔΤ - 58.3 %) at 350 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 271 degrees Celsius (% Bench ΔΤ - 61.7 %) at 450 degrees Celsius temperature inside heating element, may provide Bench ΔΤ of 324 degrees Celsius (% Bench ΔΤ - 59.8 %) at 550 degrees Celsius temperature inside heating element, may provide a Bench ΔΤ of 392 degrees Celsius (% Bench ΔΤ - 61.2 %) at 650 degrees Celsius temperature inside heating element and may provide a Bench ΔΤ of 459 degrees Celsius (% Bench ΔΤ - 62.4 %) at 750 degrees Celsius temperature inside heating element.

[0061] Example 1

[0062] Multi-layered flexible heat insulator system of 8 mm thickness with predetermined length tested for Bench ΔΤ measurement every 50 degrees Celsius in accordance with an embodiment described hereinbefore. Samples were taken in triplicates and average values recorded.

3 650 636 260 376 59.1

4 600 590 240 350 59.3

5 550 535 215 320 59.8

6 500 479 174 305 63.7

7 450 439 165 274 62.4

8 400 378 153 225 59.5

9 350 335 139 196 58.5

[0063] Example 2

[0064] Multi-layered flexible heat insulator system of 8 mm thickness with predetermined length tested for water resistance in accordance with an embodiment described hereinbefore and Bench ΔΤ measurement recorded for every 50 degrees Celsius. Samples were taken in triplicates and average values recorded.

[0065] Example 3

[0066] Multi-layered flexible heat insulator system of 8 mm thickness with predetermined length tested for mud resistance in accordance with an embodiment described hereinbefore and Bench ΔΤ measurement recorded for every 50 degrees Celsius. Samples were taken in triplicates and average values recorded.

[0067] Example 4

[0068] Multi-layered flexible heat insulator system of 8 mm thickness with predetermined length tested for high temperature durability and thermal shock resistance in accordance with an embodiment described hereinbefore and Bench ΔΤ measurement recorded for every 50 degrees Celsius. Samples were taken in triplicates and average values recorded. Sr. Temperature Temperature Temperature Bench Percent

No. inside on skin of on skin of Level ΔΤ Bench

conduit in conduit in insulation (Tl - T2) Level ΔΤ degrees degrees material in

Celsius Celsius (Tl) degrees

Celsius (T2)

1 750 736 274 462 62.8

2 700 682 260 422 61.9

3 650 640 238 404 62.8

4 600 584 219 365 62.5

5 550 535 200 335 62.6

6 500 484 180 304 62.8

7 450 432 164 268 62.0

8 400 374 155 219 58.5

9 350 335 140 195 58.2

[0069] Example 5

[0070] Multi-layered flexible heat insulator system of 8 mm thickness with predetermined length tested for low temperature durability and thermal shock resistance in accordance with an embodiment described hereinbefore and Bench ΔΤ measurement recorded for every 50 degrees Celsius. Samples were taken in triplicates and average values recorded.

2 700 686 262 424 61.8

3 650 640 248 392 61.2

4 600 590 231 359 60.8

5 550 542 218 324 59.8

6 500 487 197 290 59.5

7 450 439 168 271 61.7

8 400 379 156 223 58.8

9 350 338 141 197 58.3

[0071] In one embodiment of the invention, the heat insulator system may be placed around a conduit containing heated gaseous or liquid substances reaching a temperature of up to 1000 degrees Celsius, wherein the conduit may have a thickness in the range of 1.5mm to 1.7mm.

[0072] In an exemplary embodiment of the invention, the heat insulator system may pass the flammability test and may not catch fire till 1000 degree Celsius, may show no structural failure at bench delta T in testing for resistance against water and mud and when exposed to high temperature shock test and low temperature shock test. [0073] In accordance with one embodiment of the invention, the heat insulator may be used in a plurality of applications including but not limited to a boiler system, a solar system, a chiller system, a genset, an exhaust systems of trucks, buses, automobiles, an engine cover, etc.

[0074] The foregoing description shall be interpreted as illustrative and not in any limiting sense. A person of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure.

Claims

WE CLAIM:

1. A multi-layer heat insulation system placed around a conduit, the system comprising: an innermost layer (101) comprising a stainless steel wire mesh, wherein inner surface of the stainless steel wire mesh is in contact with the conduit, an outermost layer (104) comprising a fabric made of glass fibre coated on both sides either by a polymer with repeating Si-O-Si units or by aluminium or by graphite, wherein the outer surface of the fabric made of glass fibre is in contact with the atmosphere, and a plurality of intermediate layers comprising at least one layer comprising a silica fibre glass cloth coated with a hydrous phyllosilicate mineral (102) and at least one layer comprising a ceramic fibre blanket (103), characterized in that, said multi-layer heat insulation system has thickness in the range of 6 mm to 15 mm and has a percentage bench ΔΤ value in the range of 57.0 % to 76.5% for a temperature of up to 1000 degree Celsius inside the conduit.

2. The system of claim 1, wherein the conduit comprises a duct, tube, channel, passage, vent or pipe with or without bends.

3. The system of claim 2, wherein the heating element is employed in a boiler system, chiller system, genset, vehicular exhaust system, solar system, engine cover, furnace, kiln, chimney or a system operating in high temperature areas.

4. The system of claim 1, wherein said system comprises a clamp (106) and guide pocket (105) arrangement as locking means to secure fastening of the multilayer heating insulation system over the heating element.

5. The system of claim 4, wherein each layer is fabricated as a flexible and mouldable system in order to cover the total surface area of the conduit.

6. The system of claim 1 , wherein said double sided coating of the outermost layer (104) comprises of silicone.

7. The system of claim 1, wherein the plurality of intermediate layers comprising at least one layer comprising silica fabric (102) is coated with vermiculite.

8. The system of claim 1, wherein the system or part thereof with predetermined length and 8mm thickness is incombustible when exposed to direct fire at a temperature of up to 800 degrees Celsius up to 5 minutes.

9. The system of claim 8, wherein the system provides a percentage bench ΔΤ value of up to 63.7% for a temperature of up to 1000 degrees Celsius and more preferably for a temperature in the range of 350 degrees Celsius to 750 degrees

Celsius inside the conduit.

10. The system of claim 1, wherein the system provides a percentage bench ΔΤ value of up to 76.5% for a temperature of up to 1000 degrees Celsius and more preferably for a temperature in the range of 550 degrees Celsius to 950 degrees Celsius inside the conduit.

11. The system of claim 9, wherein the system does not show structural failure upon testing for resistance to water and wherein the system provides percentage bench ΔΤ values up to 63.0% for a temperature of up to 1000 degrees Celsius and more preferably for a temperature in the range of 350 degrees Celsius to 750 degrees Celsius inside the conduit.

12. The system of claim 9, wherein the system does not show structural failure upon testing for resistance to mud and wherein the system provides percentage bench ΔΤ values up to 62.2% for a temperature of up to 1000 degrees Celsius and more preferably for a temperature in the range of 350 degrees Celsius to 750 degrees Celsius inside the conduit.

13. The system of claim 9, wherein the system is resistant to thermal shock when tested for durability at high temperature and provides percentage bench ΔΤ values up to 62.8% for a temperature of up to 1000 degrees Celsius and more preferably for a temperature in the range of 350 degrees Celsius to 750 degrees Celsius inside the conduit.

14. The system of claim 9, wherein the system is resistant to thermal shock when tested for durability at low temperature and provides percentage bench ΔΤ values up to 62.4% for a temperature of up to 1000 degrees Celsius and more preferably for a temperature in the range of 350 degrees Celsius to 750 degrees Celsius inside the conduit.

15. The system of claim 1, wherein the innermost layer (101) of the system is comprised of fibre glass mesh.

16. The system of claim 1, wherein the at least one of the plurality of intermediate layers of the system (102) is comprised of high silica.