GB2172547A

GB2172547A - Heat insulating material and heat-insulated conduit

Info

Publication number: GB2172547A
Application number: GB08605830A
Authority: GB
Inventors: Naokazu Yoshiki; Noriyoshi Baba
Original assignee: Mitsubishi Metal Corp
Current assignee: Mitsubishi Metal Corp
Priority date: 1985-03-19
Filing date: 1986-03-10
Publication date: 1986-09-24
Also published as: GB2172547B; CN86102721A; CN87102362A; GB8605830D0; CN1006187B; DE3609029A1; CN1003730B; DE3609029C2

Abstract

A heat insulating material comprises a flat body 1 having a base 1a carrying a plurality of air chambers R each having an open top and defined on at least one side of the base by means of ribs 1b having a rigidity of such a degree as not to be collapsed in use of the heat insulating material. At least one projection 1d is provided in bottom of each air chamber and has a rigidity of such a degree as not to be collapsed in use of the heat insulating material. An aluminium foil 2 is applied to at least one side of the flat body. A heat-insulated conduit is also disclosed which comprises at least one tube and a heat insulating material applied to an outer peripheral surface of the tube to cover the same. <IMAGE>

Description

SPECIFICATION Heat insulating material and heat-insulated conduit Field of the invention The present invention relates to a heat insulating material which is superior in heat insulating effect, and also to a heat-insulated conduit.

Conventional heat insulating materials utilized to cover tubes or pipes for use in air conditioning, for example, include glass wool, rock wool, foamed plastics and the like. It is difficult to say, however, that such heat insulating materials have sufficient heat insulating effect.

In addition, a conduit having the tube covered with any one of the conventional heat insulating materials has suffered from such problems that the conduit has no sufficient heat insulating effect and heat loss of a heating medium flowing through the tube is relatively high.

An object of the present invention is to provide a heat insulating material which prevents heat from being transferred by heat conduction, heat convection and heat radiation, to perform a superior heat insulating action.

Another object of the present invention is to provide a heat-insulated conduit which can considerably reduce heat loss of a heating medium flowing through a tube.

According to the present invention, there is provided a heat insulating material comprising: a flat body including a base, a plurality of ribs cooperating with each other to define a plurality of air chambers on at least one of both sides of the base, each of the air chambers having an open top and a bottom, each of the ribs having a rigidity of such a degree as not to be collapsed in use of the heat insulating material, at least one projection formed on the bottom of each of the air chambers and having a rigidity of such a degree as not to be collapsed in use of the heat insulating material; and an aluminium foil attached to at least one of both sides of the flat body.

According to the present invention, there is further provided a heat-insulated conduit comprising: at least one tube; and a heat insulating material applied to an outer peripheral surface of the tube to cover the same, the heat insulating material comprising a strip-like body including a base, a plurality of ribs cooperating with each other to define a plurality of air chambers on at least one of both sides of the base, each of air chambers having an open top and a bottom, each of the ribs having a rigidity of such a degree as not to be collapsed when the heat insulating material is applied to the outer peripheral surface of the tube, and at least one projection formed on the bottom of each of the air chambers and having a rigidity of such a degree as not to be collapsed when the heat insulating material is applied to the outer peripheral surface of the tube.

Figure 1 is a fragmentary plan view of a heat insulating material in accordance with a principal embodiment of the present invention; Figure 2 is an enlarged cross-sectional view taken along the line ll-ll in Figure 1; Figure 3 is an enlarged cross-sectional view taken along the line Ill-Ill in Figure 1; Figure 4 is a fragmental perspective view of a first embodiment of a heat-insulated conduit, in accordance with the present invention, which has incorpo rated therein the heat insulating material shown in Figures 1 through 3; Figure 5 is a cross-sectional view taken along the line V-V in Figure 4; Figure 6 is a view similar to Figure 4, but showing a second embodiment of the heat-insulated conduit; Figure 7 is a cross-sectional view taken along the line VII-VII in Figure 6;; Figure 8 is a view similar to Figure 4, but showing a third embodiment of the heat-insulated conduit; Figure 9 is a cross-sectional view taken along the line IX-IX in Figure 8; Figure 10 is a view similar to Figure 4, but showing a fourth embodiment of the heat-insulated conduit; Figure 11 is a cross-sectional view taken along the lineXl-Xl in Figure 10; Figure 12 is a view similar to Figure 4, but showing a fifth embodiment of the heat-insulated conduit; Figure 13 is a cross-sectional view taken along the line XIII-XIII in Figure 12; Figure 14 is a view similar to Figure 4, but showing a sixth embodiment of the heat-insulated conduit; Figure 15 is a cross-sectional view taken along the line XV-XV in Figure 14;; Figure 16 is a view similar to Figure 4, but showing a seventh embodiment of the heat-insulated conduit; Figure 17 is a cross-sectional view taken along the lineXVll-XVlI in Figure 16; Figure 18 is a view similar to Figure 4, but showing an eighth embodiment of heat-insulated conduit; Figure 19 is a cross-sectional view taken along the line XIX-XIX in Figure 18; Figure 20 is a view similar to Figure 4, but showing a ninth embodiment of the heat-insulated conduit; Figure 2 1 is a cross-sectional view taken along the line XXI-XXI in Figure 20; Figure 22 is a view similar to Figure 4, but showing a tenth embodiment of the heat-insulated conduit; Figure 23 is a cross-sectional view taken along the line XXIII-XXIII in Figure 22;; Figure 24 is a view similar to Figure 4, but showing an eleventh embodiment of the heat-insulated conduit; Figure 25 is a cross-sectional view taken along the line XXV-XXV in Figure 24; Figure 26 is a view similar to Figure 4, but showing a twelfth embodiment of the heat-insulated conduit; Figure 27 is a cross-sectional view taken along the line XXVII-XXVII in Figure 26; Figure 28 is a view similar to Figure 4, but showing a thirteenth embodiment of the heat-insulated conduit; Figure 29 is a cross-sectional view taken along the line XXIX-XXIX in Figure 28; Figure 30 is a view similar to Figure 4, but showing a fourteenth embodiment of the heat-insulated conduit; Figure 31 is a cross-sectional view taken along the line XXXI-XXXI in Figure 30; Figure 32 is a view similar to Figure 4, but showing a fifteenth embodiment of the heat-insulated conduit;; Figure 33 is a cross-sectional view taken along the line XXXIII-XXXIII in Figure 32; Figure 34 is a view similar to Figure 4, but showing a sixteenth embodiment of the heat-insulated conduit; Figure 35 is a cross-sectional view taken along the line XXXV-XXXV in Figure 34; Figure 36 is a view similar to Figure 4, but showing a seventeenth embodiment of the heat-insulated conduit; Figure 37 is a cross-sectional view taken along the line XXXVII-XXXVII in Figure 36 Figure 38 is a fragmental diagrammatic view showing a first manner in which a strip of heat insulating material is wound around a tube; Figure 39 is a view similar to Figure 38, but showing a second winding manner; Figure 40 is a view similar to Figure 38, but showing a third winding manner; Figure 41 is a view similar to Figure 38, but showing a fourth winding manner; and Figure 42 is a view similar to Figure 38, but showing a fifth winding manner.

Detailed description of the preferred embodiments Various embodiments of the present invention will now be described with reference to the accompanying drawings in which the same reference numerals are used to designate like parts or elements.

Referring first to Figures 1 through 3, a heat insulating material, generally designated by the reference numeral 3, in accordance with a principal embodiment of the present invention comprises a flat body 1 which is formed by an integral molding of a transparent plastic material or the like. The flat body 1 comprises a base la and a plurality of ribs ib provided on one side of the base 1 a. The ribs 1 b are arranged on the side of the base 1 a so that four adjacent ribs 1 b in each set cooperate with each other to define a corresponding one of a plurality of rhombic air chambers R each of which has an open top a bottom formed by a surface portion of the base 1 a.Four adjacent ribs 1 b in each set are spaced from each other to define four cut-outs Ic which are located at four corners of the corresponding rhombic air chamber R, respectively. A projection 1d having a circularcross-section is provided on the bottom of each air chamber R. As shown in Figures 2 and 3, each rib ibis triangular in cross-section and has a small top or substantially sharp top. Each projection 1d has a rounded top which is small similarly to the top of each rib 1 b. An aluminium foil 2 is attached to the other side of the flat body 1.

In this manner, the heat insulating material 3 is comprised of the flat body 1 and the aluminium foil 2. Each rib ib and each projection 1 d of flat body 1 have rigidity of such a degree as notto be collapsed in use of the heat insulating material 3.

Specifically, since, as will be described later, the heat insulating material 3 is utilized in such a manner that it is interposed between two substances between which heat should be prevented from being transferred, the ribs ib and the projections id are required, in such use, to have a rigidity of such a degree as not to be collapsed, but as to be capable of maintaining the formed state of the air chambers R. For this reason, material, thickness, diameter and the like ofthe ribs 1 and the projections id are suitably selected and set depending upon the conditions in which the heat insulating material 3 is used, so that the ribs 1 b and the projections id have an appropriate rigidity.

Figures 4 and 5 show a first embodiment of a heat-insulated conduit in accordance with the present invention, in which the heat insulating material 3 described above is applied to a tube or pipe 4 to cover the same. In the illustrated embodiment, the heat insulating material 3 is formed into a strip in which, as viewed in Figure 1, right and left side edges of the heat insulating material 3 extend longitudinally of the strip, and is helically wound around the tube 4. For this purpose, as shown in Figure 1, an overlap width le is formed at one side edge or the left side edge, as viewed in Figure 1, of the heat insulating material 3, so that when it is helically wound around the tube 4, no gap or step occurs between each pair of adjacent turns.

The tube 4 is utilized to allow a heating medium such as, for example, hot water, cold water or the like to flow therethrough, and is made of a metal such as, for example, copper or the like, or of polyvinyl chloride resin or the like. The heat insulating material 3 is applied to the tube 4 so as to directly cover the outer peripheral surface thereof, with the air chambers R being located at the inner peripheral side of the applied heat insulating material 3 and with the aluminium foil 2 being located at the outer peripheral side thereof. Accordingly, the open tops of the respective air chambers R are covered by the outer peripheral surface of the tube 4, and the air chambers R are closed independently from each other even though they are more or less in communication with each other through the cut-outs 1 c.

In the embodiment shown in Figures 4 and 5, the aluminium foil 2 of the heat insulating material 3 has a glossy inner peripheral surface. In addition, the outer peripheral surface of the heat insulating material 3 is covered with an outer covering or sheath indicated by the two-dot-and-dash line.

The above-described heat insulating material 3 with which the outer peripheral surface of the tube 4 is covered prevents heat from being transferred by heat conduction, heat convection and heat radiation, to perform a superior heat insulating action in the following manner.

The heat insulating material 3 and the tube 4 are brought into contact with each other through only the small tops of the respective ribs 1 b and the small tops of the respective projections 1 d. This allows the heat transfer area to be reduced to decrease the quantity of heat transferred between the fluid flowing through the tube 4 and the atmospheric air. The heat transfer occurs from the inside to the outside of the conduit when a high temperature heating medium is caused to flow through the tube 4, whereas the heat transfer occurs from the outside to the inside of the conduit when a low temperature heating medium is caused to flow through the tube 4. Furthermore, since a considerable amount of air is contained within the air chambers R, the airfunctions as a nonconductor of heat to further reduce the heat transfer.The air chambers R independent or isolated from each other would enable the recirculation of the air within each air chamber R due to the convection, to be minimized. Accordingly, the quantity of heat transferred due to the convection would be extremely small. Additionally, the aluminium foil 2 of the heat insulating material 3 restrains the heat radiation. In the embodiment shown in Figures 4 and 5, since the inner peripheral surface of the aluminium foil 2 is glossy, when a high temperature heating medium is caused to flow through the tube 4, the heat radiated from the inside to the outside of the conduit is reflected by the glossy inner surface of the aluminium foil 2, and the heat transfer is restrained by the quantity of the reflected heat. In this connection, it is extremely advantageous in the heat radiation that the flat body 1 is transparent.

Moreover, inasmuch as the ribs 1 b defining the air chambers R in the heat insulating material 3 and the central projections id have a rigidity of such a degree as not to be collapsed in such use, as shown in Figures 4 and 5, the air chambers R are not so much deformed and all of the air chambers R exist as similar rhombic chambers. The projections 1d perform an important part or role in this respect, and support the central portions of the respective air chambers R to keep the configuration thereof. Thus, the heat insulating material 3 performs the abovedescribed heat insulating action uniformly and positively around the tube 4 by the air chambers R which reliably exist in the similar configuration.Incidentally, if the air chambers R in the heat insulating material 3 are formed into closed or sealed air chambers by a polyethylene film having a thickness of the order of 200 am, i.e., if closed or sealed air chambers in such a form that the tops of the respective air chambers R in the heat insulating material 3 in accordance with the present invention are closed are beforehand formed by a low strength material, such air chambers would tend to be deformed and collapsed under static load and the like in use in which the heat insulating material having therein the closed air chambers is wound around the tube 4, and there would be a possibility that air escapes from the air chambers.In addition, if the conduit, in which the tube 4 has wound therearound the heat insulating material having therein such closed or sealed air chambers, is massproduced, the closed or sealed air chambers would tend to be collapsed and there would be a possibility that air could escape from the air chambers, when the conduit having the tube around which the heat insulating material is wound is caused to pass through a nip between feeding rollers or a nip between guide rollers, so that there would be a fear that the heat insulating material cannot perform its heat insulating action as expected.In these respects, superior effectivenesses are displayed by the heat insulating material 3 in accordance with the present invention which has such features that the air chambers R are open at their respective tops, that a predetermined rigidity is given to the ribs ib which define the air chambers R, and that the projections id having a predetermined rigidity are respectively provided on the bottoms of the respective air chambers R.

Moreover, in the embodiment shown in Figures 4 and 5, since each air chamber R is in the form of a rhombus, when the heat insulating material 3 is helically wound around the tube 4, the ribs 1 are disposed so as to be inclined with respect to the winding direction of the heat insulating material 3, so that the resistance due to the rigidity of the ribs 1 b against the tube 4 is reduced. In addition, upon the winding of the heat insulating material 3, the cut-outs ic relieve the bending resistance of the ribs 1 b, and prevent winkles or creases from occurring on the ribs 1 b. This enables the heat insulating material 3 to be uniformly applied around the tube 4.

Figures 6 and 7 show a second embodiment of the heat-insulated conduit in accordance with the present invention, in which the heat insulating material 3 is indirectly applied to the tube 4 through a heat insulating tape 5 wound therearound.

Specifically, the outer peripheral surface of the tube 4 is first covered with the heat insulating tape 5, and then the heat insulating material 3 is applied to the tube 4 so as to cover the heat insulating tape 5.

The heat insulating tape 5 is comprised of a base made of a heat-resistant and heat-insulating material such as, for example, glass cloth, nonwoven or woven fabric of synthetic fiber such as polyester, or the like, and an aluminium foil applied to or aluminium vapor-deposited on an outer surface of the base. The provision of the heat insulating tape 5 provides additional heat insulating effect. If the aluminium foil of the heat insulating tape 5 has a glossy inner surface, it would be possible to expect the reflection of radiant heat, similarly to the aluminium foil 2 of the heat insulating material 3.

Figures 8 and 9 show a third embodiment of the heat-insulated conduit in accordance with the present invention, which further comprises a heat insulating tape 6 and an outer covering or sheath 7, in addition to the components of the conduit illustrated in Figures 6 and 7. Specifically, the outer periphery of the wound heat-insulating material 3 is covered with the heat insulating tape 6 similar to the above-described heat insulating tape 5, and is covered also with the sheath 7. The sheath 7 is made of polyester resin or the like having both heatinsulation and strength in order to promote the heat insulating effect and to protect the coverings located inside the sheath 7. In addition, the heat insulating tape 6 has also a glossy inner surface, so that it would be possible to expect the reflection of radiant heat similar to that of the aluminium foil 2 in the heat insulating material 3.

Although the embodiments shown respectively in Figures 1 to 3, Figures 4 and 5 and Figures 6 and 7 have been described as being such that the aluminium foil 2 of the heat insulating material 3 has the glossy inner surface, the outer surface of the aluminium foil 2 may be glossy. In this case, since the glossy outer surface of the aluminium foil 2 has smaller area as compared with a dim surface thereof, it is possible to reduce the degree of heat radiation through the aluminium foil 2 to the outside.

It is needless to say that both the inner and outer surfaces of the aluminium foil 2 may be glossy. The aluminium foil in each of the heat insulating tapes 5 and 6 may have the outer surface which is glossy, so that it is possible to reduce the degree of heat radiation to the outside, similarly to the heat insulating material 3.

Figures 10 and 11 show a fourth embodiment of the heat-insulated conduit in accordance with the present invention, which comprises two tubes 4 and 4 and a spacer 8 interposed therebetween. The heat insulating tape 5, the heat insulating material 3, the heat insulating tape 6 and the sheath 7 are applied to an assembly of the two tubes 4 and 4 and the spacer 8 in a manner similar to that described with reference to the embodiment illustrated in Figures 8 and 9, to thereby cover the assembly.

Figures 12 and 13 show a fifth embodimentofthe heat-insulated conduit in accordance with the present invention, which comprises two tubes 4 and 4.

The heat insulating tape 5 and the heat insulating material 3 are applied to each of the tubes 4 and 4 to coverthe same, and the heat insulating tape 5 and the sheath 7 are common to the covered two tubes 4 and 4, i.e., are applied to an assembly of the covered tubes 4 and 4 to cover the same.

Figures 14 and 15 shown a sixth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the third embodiment illustrated in Figures 8 and 9, but comprises the sheath 7 having ridges 7a formed on the inner peripheral surface thereof. The ridges 7a each of which is triangular in cross-section are circumferentially spaced from each other and extend longitudinally of the tube 4. It is possible for the embodiment shown in Figures 14 and 15 to reduce the contact area between the heat insulating tape 6 and the sheath 7. In addition, air in a space defined by the heat insulating tape 6 and each pair of adjacent ridges 7a and 7a would enable the heat insulating effect to be further improved.

Figures 16 and 17 show a seventh embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the fourth embodiment illustrated in Figures 10 and 11, but comprises the sheath 7 having formed on the inner peripheral surface thereof ridges 7a similar to those described with referenceto Figures 14 and 15.

Figures 18 and 19 show an eighth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the fifth embodiment illustrated in Figures 12 and 13, but comprises the sheath 7 having formed on the inner peripheral surface thereof ridges 7a similar to those described with reference to Figures 14 and 15.

Figures 20 and 21 show a ninth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the sixth embodiment illustrated in Figures 14 and 15, but comprises the sheath 7 having the irregular outer peripheral surface like a so-called knurled surface. The irregular outer peripheral surface of the sheath 7 prevents wrinkles or creases thereon from being highlighted, to aim at the improvement of an appearance of the sheath 7.

Figures 22 and 23 show a tenth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the seventh embodiment illustrated in Figures 16 and 17, but comprises the sheath 7 having the irregular outer peripheral surface similar to that described with reference to Figures 20 and 21.

Figures 24 and 25 show an eleventh embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the eighth embodiment illustrated in Figures 18 and 19, but comprises the sheath 7 having the irregular outer peripheral surface similar to that described with reference to Figures 20 and 21.

Figures 26 and 27 show a twelfth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar to the third embodiment illustrated in Figures 8 and 9, but is different therefrom in that the sheath 7 has formed on the outer peripheral surface a plurality of peripheral grooves 7b spaced from each other longitudinally of the tube 4, and a peripheral gap 9 is left between the sheath 7 and the wound heat insulating tape 6. The peripheral grooves 7b facilitate the bending of the heat-insulated conduit without the substantial decrease in the strength of the sheath 7 against the external pressure. The gap 9 is provided for aiming atthefurther improvement of the heat insulation.

Figures 28 and 29 show a thirteenth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the fourth embodiment illustrated in Figures 10 and 11, but comprises peripheral grooves 7b and a peripheral gap 9 similar to those described with reference to Figures 26 and 27.

Figures 30 and 31 show a fourteenth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the fifth embodiment illustrated in Figures 12 and 13, but further comprises a corrugated tube 10. The corrugated tube 10 has formed on an outer peripheral surface thereof a plurality of peripheral grooves 10a spaced from each other longitudinally of the tubes 4 and 4. The sheath 7 is covered with the corrugated tube 10 with a peripheral gap 11 being lefttherebetween.

Figures 32 and 33 show a fifteenth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the sixth embodiment illustrated in Figure 14 and 15, but further comprises a corrugated tube 10 similar to that described with reference to Figures 30 and 31.

Figures 34 and 35 show a sixteenth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the seventh embodiment illustrated in Figures 16 and 17, but further comprises a corrugated tube 10 similar to that described with reference to Figures 30 and 31.

Figures 36 and 37 show a seventeenth embodiment of the heat-insulated conduit in accordance with the present invention, which is similar in structure to the eighth embodiment illustrated in Figures 18 and 19, but further comprises a corrugated tube 10 similar to that described with reference to Figures 30 and 31.

In each of the third, fourth and fifth embodiments respectively shown in Figures 8 and 9, Figures 10 and 11 and Figures 12 and 13, if the outer surface of the aluminium foil in the heat insulating tape 5 is selected so as to be glossy and the inner surface of the aluminium foil in the heat insulating tape 6 is selected so as to be glossy, it would be possible to reflect heat inwardly through the heat insulating material 3 to sufficiently restrain the heat radiation.

In addition, in each of the sixth to fourteenth embodiments shown in Figures 14 through 31, if the outer surface of the aluminium foil 2 located at the outer surface of the heat insulating material 3 is selected so as to be glossy, it would be possible to restrain the heat radiation from the aluminium foil 2 to sufficiently reduce the release of heat by the air heat insulation due to the air layer formed by the ridges 7a on the sheath 7 of each of the embodiments shown in Figures 14through 25, or due to the gap 9, 11 of each of the embodiments shown in Figures 26 through 31.

Although each embodiment has been described as having the air chambers R disposed on one side of the base 1 a of the flat body 1,the air chambers R may be arranged on both sides of the base 1a. In addition, the flat body 1 should not be limited to an integrally molded one, but may be one formed by assembling a plurality of parts or components with each other. Furthermore, each air chamber R may have a circular or polygonal configuration in plan or may have any other configuration. The arrangement or disposition of the air chambers R may be suitably selected, and may be regular in a zigzag manner, or may be irregular. The cross-sectional configuration of the ribs 1 b, the configuration and the number of the projections id are also optional, and the cut-outs 1c may not be provided.The aluminium foil 2 may be applied to the side of the flat body 1 at which the air chambers R are disposed, or may be applied to both sides of the flat body 1.

Moreover, the heat insulating material 3 may be applied to the tube 4 with the air chambers R being located at the outer peripheral side of the applied heat insulating material 3. Alternatively, the heat insulating material 3 in the form of a strip may be applied to the tube 4 in such a manner that the heat insulating material 3 extends longitudinally along the tube 4. It should be particularly noted that the heat insulating material 3 shown in Figures 1 through 3 may be widely applicable to any other components, members, instruments and the like than tubes, which are to be heat-insulated. It should also be noted that the aluminium foil 2 is not essential to each of the embodiments shown in Figure 4 through 37, but may not be provided.

Figures 38 through 42 illustrate various manners in which the heat insulating material 3 in the form of a strip similar to that described with reference to Figures 4 and 5 is wound around the tube 4.

Figure 38 shows a first winding manner in which the heat insulating material 3 is helically wound around the outer periphery 4a of the tube 4 from the left to the right in Figure 38 along the length of the tube 4, to form a heat-insulated conduit 15. The heat insulating material 3 is wound in an S-twist an indicated by the levelled character "S" in Figure 38.

One of each pair of adjacent turns of the wound heat insulating material 3 has a side edge closely abutting against the adjacent side edge of the other turn to entirely cover the outer peripheral surface 4a of the tube 4.

Figure 39 shows a second winding manner in which the heat insulating material 3 is helically wound around the outer peripheral surface 4a of the tube 4 from the left to the right in Figure 39 along the length of the tube 4 so that one of each pair of adjacent turns of the wound heat insulating material 3 has a side edge overlapping with the adjacent side edge of the other turn, to form a heat-insulated conduit 15. In Figure 39, the heat insulating material 3 is wound in an S-twist, similarly to the manner shown in Figure 38. The overlapping of the adjacent side edges of each pair of adjacent turns allows the heat insulating material 3 to completely cover the tube 4 without any fear that a gap is formed between each pair of adjacent turns.

Figure 40 illustrates a third winding manner in which two juxtaposed heat insulating materials 3 and 3 are simultaneously wound helically around the outer peripheral surface 4a of the tube 4 from the left to the right in Figure 40 along the length of the tube 4, to form a heat-insulated conduit 15. Similarly to the manner illustrated in Figure 38, the two heat insulating materials 3 and 3 wound in an S-twist, and are closely wound double so that one of the two heat insulating materials 3 and 3 has a side edge abutting against the adjacent side edge of the other heat insulating material 3. It is possible for the winding manner shown in Figure 40 to wind the heat insulating materials 3 and 3 around the tube 4 at a speed two times that of the single winding manner shown in Figure 38.

Figure 41 illustrates a fourth winding manner in which two heat insulating materials 3 and 3 are helically wound in two layers around the outer peripheral surface 4a of the tube 4 from the left to the right in Figure 41 along the length of the tube 4, with a shift in phase of approximately 180 degrees, to form a heat-insulated conduit 15. Similarly to the manner shown in Figure 38, the two heat insulating materials 3 and 3 are wound in an S-twist and closely so that one of the two heat insulating materials 3 and 3 has a side edge abutting against the adjacent side edge of the other heat insulating material 3. In Figure 41, the abutting portion between the adjacent side edges of the first layer of heat insulating material 3, i.e., the helical seam portion is covered with a longitudinally extending central portion of the second layer of heat insulating material 3, to prevent the heat insulating effect from being decreased.

Figure 42 shows a fifth winding manner in which two heat insulating materials 3 and 3 are helically wound in two layers around the outer peripheral surface 4a of the tube 4 from the left to the right in Figure 42 along the length of the tube 4, to form a heat-insulated conduit 15. The first layer of heat insulating material 3 is wound in an S-twist similar) to the manner shown in Figure 38, and is wound closely so that one of each pair of adjacent turns has a side edge abutting against the adjacent side edge of the other turn. The second layer of heat insulating material 3 is wound in a Z-twist as indicated by the levelled character "Z", opposite to the S-twist, and is wound closely so that one of each pair of adjacent turns has a side edge abutting against the adjacent side edge of the other turn.Thus, since the two heat insulating materials 3 and 3 are wound in two layers in their respective directions opposite to each other, the tension in the first layer of heat insulating material 3 cooperates with the tension in the second layer of heat insulating material 3 to preventthe materials 3 and 3 from slacking. Accordingly, the heat insulating materials 3 and 3 are wound under tension, and it would be possible to previously prevent the heat insulating effectfrom being decreased due to possible gaps between the slacking turn or turns and the tube 4 or between the slacking turn or turns of the first layer and the slacking turn or turns of the second layer.

The present invention should not be limited to the winding manners shown in Figures 38 through 42, but various modifications can be made.

As a modification of the winding manner shown in Figure 40, for example, such a winding manner is thinkable that three or more heat insulating materials 3 are wound in juxtaposed relation to each other simultaneously or with a predetermined time interval, or are wound so that one of each pair of adjacent heat insulating materials has a side edge overlapping with the adjacent side edge of the other heat insulating material.As a modification of the winding manner shown in Figure 41, such a winding manner is thinkable that three heat insulating materials 3 are wound with a shift in phase of 120 degrees, or a plurality of heat insulating materials 3 are wound with other various shifts in phase, or a plurality of heat insulating materials 3 are wound so that one of each pair of adjacent turns in each layer has a side edge overlapping with the adjacent side edge of the other turn, or a plurality of heat insulating materials 3 are wound so that one of each pair of adjacent turns in each layer has a side edge spaced from the adjacent side edge of the other turn a predetermined distance to form a helical gap therebetween, and a subsequent layer is wound in offset relation to the previous layer to cover the helical gap therein.Moreover, as a modification of the winding manner shown in Figure 42, such a winding manner is thinkable that one of each pair of adjacent turns in each layer has a side edge overlapping with the adjacent side edge of the other turn, or three or more heat insulating materials are wound in multiple layers alternately in S-and Z-twist, or a plurality of heat insulating materials 3 are wound so that one of each pair of adjacent turns in each layer has a side edge spaced from the adjacent side edge oftheotherturn a predetermined distance to form a helical gap therebetween, and a subsequent layer is wound in offset relation to the previous layer to cover the helical gap therein.The winding manner in which the heat insulating materials 3 are wound so that one of each pair of adjacent turns has a side edge spaced from the adjacent side edge of the other turn, would not injure the flexibility of the heatinsulated conduit 15. If the heat insulating material 3 as shown in Figures 1 to 3 is wound in an overlapping fashion, it would be preferable in view of the heat insulation to cause an overlap width 1 e of one of each pair of adjacent turns to closely overlap with the adjacent side edge of the other turn.

Furthermore, at least one heat insulating material 3 may be wound by a suitable combination of two or more of the winding manners shown in Figures 38 through 42 and their modifications described above.

When a plurality of heat insulating materials 3 are wound, one of them may be wound from one end of the tube toward the other end thereof and another heat insulating material may be wound from the other end of the tube toward the one end thereof. In brief, any suitable winding manner may be utilized if at least one heat insulating material 3 is helically wound around the tube 4 along the length thereof.

As described above, a heat insulating material in accordance with the present invention is arranged so that a plurality of air chambers each having an open top are formed on at least one side of a base of a flat body and an aluminium foil is applied to at least one side of the flat body. With such arrangement of the present invention, it is possible to prevent heat from being transferred due to heat conduction, heat convection and heat radiation, to provide superior heat insulating effect. In addition, a rigidity of such a degree as not to be collapsed in use of the heat insulating material is given to ribs which define the air chambers, and a rigidity of such a degree as not to be collapsed in use of the heat insulating material is given to at least one projection provided on a bottom of each air chamber.Accordingly, all ofthe air chambers reliably exist in similar configuration, and it is possible for the heat insulating material to reliably perform a heat insulating action as expected.

In addition, a heat-insulated conduit in accordance with the present invention is arranged so that at least one tube is covered with the heat insulating material which comprises a plurality of air chambers. With such arrangement, superior heat insulating effect of the heat insulating material allows heat loss of a heating medium to be considerably reduced.

Moreover, a rigidity of such a degree as not to be collapsed when the heat insulating material is applied to the outer peripheral surface of the tube is given to ribs which define the air chambers, and a rigidity of such a degree as not to be collapsed when the heat insulating material is applied to the outer peripheral surface of the tube is given to at least one projection provided on a bottom of each air chamber. Accordingly, all of the air chambers reliably exist in similar configuration, and it is possible for the heat insulating material to reliably perform a heat insulating action as expected.

Claims

1. A heat insulating material comprising; a flat body including a base, a plurality of ribs cooperating with each other to define a plurality of air chambers on at least one of both sides of said base, each of said air chambers having an open top and a bottom, each of said ribs having a rigidity of such a degree as not to be collapsed in use of the heat insulating material, and at least one projection formed on the bottom of each of said air chambers and having a rigidity of such a degree as not be collapsed in use of the heat insulating material; and an aluminium foil attached to at least one of both sides of said flat body.

2. A heat insulating material as defined in claim 1, wherein said flat body is formed by an integral molding.

3. A heat insulating material as defined in claim 2, wherein said flat body is made of a transparent plastic material.

4. A heat insulating material as defined in claim 2, wherein said air chambers are isolated from each other.

5. A heat insulating material as defined in claim 4, wherein four adjacent ribs in each set cooperate with each other to define a corresponding one of said air chambers, which is in the form of a rhombus.

6. A heat insulating material as defined in claim 5, wherein four adjacent ribs in each set are spaced from each other to define four cut-outs respectively located at four corners of the rhombic air chamber.

7. A heat insulating material as defined in claim 1, wherein each of said ribs has a small top and each of said projections has a small top.

8. A heat insulating material as defined in claim 7, wherein each of said ribs is triangular in crosssection and has a sharp top, and each of said projections has a rounded top.

9. A heat insulating material as defined in claim 1, wherein at least one side of said aluminium foil is glossy.

10. A heat-insulated conduit comprising: at least one tube; and a heat insulated material applied to an outer peripheral surface of said tube to cover the same, said heat insulating material comprising a strip-like body including a base, a plurality of ribs cooperating with each other to define a plurality of air chambers on at least one of both sides of said base, each of said air chambers having an open top and a bottom, each of said ribs having a rigidity of such a degree as not to be collapsed when said heat insulating material is applied to the outer peripheral surface of said tube, and at least projection formed on the bottom of each of said air chambers and having a rigidity of such a degree as not to be collapsed when said heat insulating material is applied to the outer peripheral surface of said tube.

11. A heat-insulated conduit as defined in claim 10, wherein said heat insulating material includes an aluminium foil attached to at least one of both sides of said strip-like body.

12. A heat-insulated conduit as defined in claim 10, wherein said strip-like body is formed by an integral molding.

13. A heat-insulated conduit as defined in claim 12, wherein said strip-like body is made of a transparent plastic material.

14. A heat-insulated conduit as defined in claim 10, wherein said air chambers are isolated from each other.

15. A heat-insulated conduit as defined in claim 14, wherein four adjacent ribs in each set cooperate with each other to define a corresponding one of said air chambers, which is in the form of a rhombus.

16. A heat-insulated conduit as defined in claim 15, wherein four adjacent ribs in each set are spaced from each other to define four cut-outs respectively located at four corners of the rhombic air chamber.

17. A heat-insulated conduit as defined in claim 10, wherein each of said ribs has a small top and each of said projections has a small top.

18. A heat-insulated conduit as defined in claim 17, wherein each of said ribs is triangular in crosssection and has a sharp top, and each of said projections has a rounded top.

19. A heat-insulated conduit as defined in claim 11, wherein at least one side of said aluminium foil is glossy.

20. A heat-insulated conduit as defined in claim 10, wherein tops of the respective ribs and tops of the respective projections are brought into direct contact with the outer peripheral surface of said tube.

21. A heat-insulated conduit as defined in claim 10, including: a heat insulating tape wound around said tube;and said heat insulating material being applied to the outer peripheral surface of said tube through the wound heat insulating tape, with tops of the respective ribs and tops of the respective projections being brought into contact with the wound heat insulating tape.

22. A heat-insulated conduit as defined in claim 21, including: a further heat insulating tape wound around said heat insulating material; and a sheath covering an outer peripheral surface of the wound further heat insulated tape.

23. A heat-insulated conduit as defined in claim 22, wherein said sheath has formed on an inner peripheral surface thereof a plurality of circumferentially spaced ridges extending longitudinally of said tube.

24. A heat-insulated conduit as defined in claim 23, wherein said sheath has an irregular outer peripheral surface.

25. A heat-insulated conduit as defined in claim 22, wherein a gap is left between said sheath and the wound further heat insulating tape, and said sheath has formed on an outer peripheral surface thereof a plurality of peripheral grooves spaced from each other longitudinally of said tube.

26. A heat-insulated conduit as defined in claim 23, including: a corrugated tube with which said sheath is covered, with a gap being left between said corrugated tube and said sheath.

27. A heat-insulated conduit as defined in claim 22, including: a plurality of tubes arranged in parallel to each other; spacer means disposed between said tubes; and the first-mentioned heat insulating tape being wound around an assembly of said tubes and said spacer means.

28. A heat-insulated conduit as defined in claim 27, wherein said sheath has formed on an inner peripheral surface thereof a plurality of circumferentially spaced ridges extending longitudinally of said tube.

29. A heat-insulated conduit as defined in claim 28, wherein said sheath has an irregular outer peripheral surface.

30. A heat-insulated conduit as defined in claim 27,wherein a gap is left between said sheath and the wound further heat insulating tape, and said sheath has formed on an outer peripheral surface thereof a plurality of peripheral grooves spaced from each other longitudinally of said tube.

31. A heat-insulated conduit as defined in claim 28, including: a corrugated tube with which said sheath is covered, with a gap being left between said corrugated tube and said sheath.

32. A heat-insulated conduit as defined in claim 22, including: a plurality of tubes arranged in parallel to each other; the first-mentioned heat insulating tape and said heat insulating material being applied to each of said tubes; and said further heat insulating tape and said sheath being common to said tubes.

33. A heat-insulated conduit as defined in claim 32, wherein said sheath has formed on an inner peripheral surface thereof a plurality of circumferentially spaced ridges extending longitudinally of said tubes.

34. A heat-insulated conduit as defined in claim 33, wherein said sheath has an irregular outer peripheral surface.

35. A heat-insulated conduit as defined in claim 32, wherein a gap is left between said sheath and the wound further heat insulating tape, and said sheath has formed on an outer peripheral surface thereof a plurality of peripheral grooves spaced from each other longitudinally of said tubes

36. A heat-insulated conduit as defined in claim 33, including: a corrugated tube with which said sheath is covered, with a gap being left between said corrugated tube and said sheath.

37. A heat-insulated conduit as defined in claim 10, wherein said heat insulating material is helically wound around said tube.

38. A heat-insulated conduit as defined in claim 37, wherein one of each pair of adjacentturns has a side edge abutting against the adjacent side edge of the other turn.

39. A heat-insulated conduit as defined in claim 37, wherein one of each pair of adjacent turns has a side edge overlapping with the adjacent side edge of the other turn.

40. A heat-insulated conduit as defined in claim 10, including: first and second heat insulating materials helically wound around said tube with a side edge of said first heat insulating material abutting against the adjacent side edge of said second heat insulating material.

41. A heat-insulated conduit as defined in claim 10, including: first and second heat insulating materials helically wound double around said tube with a shift in phase of approximately 180 degrees.

42. A heat-insulated conduit as defined in claim 10, including: first heat insulating material helicallywound around said tube in a first direction; and a second heat insulating material helically wound around said tube in a second direction opposite to said first direction.