MXPA99001664A - Body conformed in the form of plate and evacuated, process for thermal insulation and use of the body conform - Google Patents

Abstract

The present invention relates to a method for isolating curved surfaces with thermally insulating material, said method being characterized in that it comprises placing one or more layers of an evacuated molded element comprising a molded element in the form of a sheet, evacuated, surrounded by sheath and thermally insulator, comprising microporous, pressed and optionally hardened insulating material, wherein the molded element has a surface with a laminar structure, the sheets comprising elongated incisions in the surface having a depth of 40 to 95% of the thickness of the molded element, adjacent to the curved surface, the side of the insulating material having the laminar structure against the curved surface, and collapsing the void in at least one layer of one or more molded elements evacuated

Description

BODY CONFORMED IN THE FORM OF PLATE AND EVACUATED, PROCESS FOR THERMAL INSULATION AND EMPLOYMENT OF THE BODY CONFORMED Object of the invention is a body shaped plate, evacuated and calorifugante, containing a base microporous insulating material, pressed and optionally hardened. Object of the invention are additionally a process for thermal insulation of curved faces, particularly tubes and the application of the shaped body. DE-4432896 Al discloses a heat-insulating shaped body, evacuated and confined in a gas-tight envelope, based on a pressed and optionally hardened microporous insulating material. For the thermal insulation of bodies with curved faces, particularly tubes and cylinders, a shaped body of this type is suitable only with certain limitations. Thus, a high energy consumption is necessary in order to adapt the shaped body to a curved face. The coating of the face is incomplete most of the time, due to the rigidity of the material and the existing tolerances of the surface that can be measured. This, and the inevitable folds in the adaptation of the shaped body to the curved face are the cause of poor thermal insulation. The use of a thick shaped body for thermal insulation, or the thermal insulation of strongly curved faces is not possible in general, because the shaped body does not bend or does not bend sufficiently. The present invention presents how, however, effective thermal insulation of curved faces with shaped bodies of the aforementioned kind is possible. Object of the invention is a body shaped plate, evacuated and calorifugante, containing a microporous insulating material, pressed and optionally hardened, and characterized in that the insulating material is in one or more layers wrapped and evacuated, and the The shaped body has a surface with a sheet structure, in which the sheets are formed by extensive cuts on the surface and exhibit a depth of 40 to 95% of the thickness of the shaped body. Object of the invention is additionally a process for the isolation of curved faces with heat-insulating insulating material, characterized in that the claimed shaped body having the surface with sheet structure is adapted and fixed to the curved face and the vacuum is suppressed at the less in one layer. Due to the sheet structure, thicker shaped bodies can also be adapted without a particular energy consumption to curved faces, and thermally expensive faces with a limited radius of curvature can also be insulated therefrom. The residual imperfections in the thermal insulation are eliminated or reduced at least by vacuum suppression. In this way the volume of the shaped body is increased, and the diathermal cracks and tears are reduced or closed. In case a particularly effective thermal insulation is required, a multi-layer shaped body construction consisting of two to five or more layers is preferred. In this case, the layers can be arranged in such a way that an offset arrangement occurs at the impact points, resulting in a further reduction of the heat loss. The thermal conductivity of an insulating material can be drastically reduced by decreasing the air pressure in the system. The efficiency of a microporous insulating material can be improved up to ten times, when the partial pressure within the insulating material is reduced below 5 to 10 millibars, the magnitude of the depression determining the efficiency of the lagging. Particularly efficient lagging is achieved when the shaped body used for the lagging is formed by several layers and the vacuum is not eliminated in all layers, at least one layer remaining in the evacuated state. By the use of appropriate wrappings, for example multilayer sheets, the stability of the residual vacuum can be maintained over several years. With a shaped body of this type having evacuated and non-evacuated layers, for example, pipelines can be isolated more cost-effectively and with greater technical efficiency than with known systems. Thanks to the cuts in the surface, and the existing depression in the gas-tight envelope, the sheet, depending on its rigidity, is introduced to a certain degree in the cuts. In this way a coating of the curved face without wrinkles can be ensured. Both things increase the efficiency of the lagging. The invention is illustrated further below with the aid of figures. Figure 1 shows a preferred embodiment of the shaped body in cross section; Figure 2 shows preferred cross-sectional shapes of the sheets of the shaped body in enlarged representation; Figure 3 shows in plan view how a tube with the shaped body is coated; Figure 4 shows a further preferred embodiment of the shaped body in cross section. The shaped body according to FIG. 1 is in the form of a plate and consists wholly or partially of a microporous insulating material 1 and a gas-tight envelope 2 (shown only partially and schematically). The body has a surface that is structured by extensive cuts 3 (sheets). The sheets have a depth t of 40 to 95%, particularly preferably 60 to 85% of the thickness d of the shaped body. A depth t of at least 5 mm is typical. The thickness d of the shaped body is deduced from the desired heat-insulating effect. The need for the use of the sheets in the shaped bodies is inferred in the case of tubes by the wall thicknesses, being dependent on the diameter of the tube > 5% of the tube diameter for small tubes (diameter approx 50 mm) and > 2% of the diameter of the tube for large tubes (diameter of at least 300 mm). Also, the rigidity of the shaped body, which depends mainly on its density, plays a role in this case. The sheets are preferably at a distance of 4 to 40 mm, particularly preferably 10 to 20 mm from one another and are preferably arranged parallel to each other, having a base width b of 0.5 to 5 mm, preferably 1 up to 3 mm. Its cross section preferably has a square, rectangular, acute angle or rounded shape, particularly one of the forms A-D shown in figure 2. The distance between the sheets depends on a part of the selected base width and on the other hand of the inner diameter that you want to achieve. If the base widths of the individual sheets are added, approximately the difference between the outer perimeter and the inside of the shaped body adjacent to the curved face should be obtained. A particularly advantageous process for isolating curved faces with heat-insulating insulating material is achieved by adapting and fixing the shaped body with its structured surface to the curved face, and then suppressing the vacuum. This is indicated in the example of the insulation of a tube 4 in figure 3. The wrapped shaped body 5 extends around the tube 4, in such a way that the surface provided with sheets rests on the peripheral face of the tube. Due to the sheet structure, it is possible to bend the shaped body according to the tube contour, even when the thickness d is relatively large and / or the radius of curvature of the tube is comparatively small. The evacuated shaped body is preferably used for pipe insulation, for example oil pipelines for crude oil and remote heat pipes, for motors, turbines and chimneys. In figure 4 a shaped body is represented, which is constituted by several wrapped and evacuated layers (an inner layer 6, an intermediate layer 7 and an outer layer 8), which contain a microporous insulating material pressed and optionally hardened. For the isolation of a curved face, the body formed with its surface having a sheet structure is adapted and fixed to the curved face, and then the vacuum is suppressed in at least one layer, it being preferred that the vacuum be maintained at least in another layer Particularly preferably, the vacuum is suppressed in the layer adjacent to the curved face, and is permanently maintained in at least one other layer. The shaped body can be glued in its entirety or in layers, for example on a tube 4 or otherwise fixed thereto, for example by wrapping a ribbon, preferably a tissue tape or an adhesive tape, a sheet of plastic material or a thin metal sheet around the shaped body adjacent to the tube, or in each case a layer of the shaped body. It is also possible to arrange and fix around the tube a metal sheet in the form of total envelopes or half-shells or appropriate cuts. The vacuum maintained in the shaped body is suppressed in at least one of the layers, in order to reduce or completely eliminate the impermeability of the thermal insulation that may remain. Due to the suppression of the vacuum, the volume of the body formed by the air intake increases, and the shaped body, when dilating, can close the joints and cracks. The vacuum can be suppressed by intentionally damaging the envelope of the layer and optionally the object that is fixed to the body formed with a tool, or even by subjecting the envelope by the influence of the environment before or during its application to mechanical or thermal stresses until it is applied. tear or thermally decomposes. The latter may occur, for example, in the case of pipeline insulation due to the high average temperatures of up to 180 ° C, which can be achieved by a suitable choice of the shell material in the case of the construction of multiple layers of the formed body decomposition only of the layer that is inside with maintenance of the vacuum in the additional layers that are more to the outside.

The shaped body is preferably produced by a process which has already been described in DE-4432896 Al. Said body also preferably has the composition indicated therein, consisting of 30 to 100% by weight of finely divided metal oxide, up to 50% by weight of opacifying agent, 0 to 50% by weight of fibrous material and 0 to 15% by weight of inorganic binder. It is also preferred to select the metal oxide, the fibrous material, the opacifying agent and the binder between the materials mentioned in DE-4432896 Al, organic fibers, for example viscose fibers, being also suitable as fibers. Optionally, filler materials such as mica, perlite, or vermiculite may also be contained. After production of the shaped body, the sheets are cut by means of milling tools or saw tools, for example sheet or wire saws, and the shaped body is incorporated in a casing, evacuated, and the casing is closed . It is convenient, although not necessarily necessary, to provide pores and channels in the shaped body to accelerate evacuation, as described in DE-4432896 Al.

EXAMPLE 1 A plate measuring 965 mm * 500 mm * 20 mm was equipped with 50 parallel cuts at a distance of 19.6 mm. The cuts had a base width of 2.5 mm. The plate thus obtained was hermetically welded in a sheet composed of multiple layers at pressures less than 200 millibars, in such a way that the initially smooth plate was already slightly curved and acted thereby as a handling aid during assembly; As a consequence of this, shorter assembly times can be achieved. Next, the plate was assembled with the surface provided with the cuts on a tube, and was fixed promptly with adhesive tape. Next, the envelope was scratched with a pointed object and the plate adjacent to the tube was tightly wrapped with the adhesive tape.

EXAMPLE 2 A tube that transports a hot medium to several hundred degrees is wrapped with three layers of sheets evacuated and welded in multi-layer sheet gas-tight with a structure of sheets incorporated on the surface that have a thickness of 12 mm each, in such a way that the shock points are offset frontally and in the perimeter. Each individual layer is fixed with adhesive tape. During use, by virtue of the thermal stability of the wrapping sheet, the first layer is thermally decomposed, whereby the sealing effect is kept active. Due to the heat-insulating action of the first layer the envelope of the immediate layers is maintained, which by virtue of the particularly satisfactory heat-dissipating effect of the evacuated systems results in an optimum insulating effect.

Claims (6)

NOVELTY OF THE INVENTION CLAIMS

1. - Body shaped plate, evacuated and heat-insulating, containing a microporous, pressed and optionally hardened insulating material, characterized in that the insulating material is in one or more layers wrapped and evacuated, and the shaped body has a surface with a structure of sheets, in which the sheets are formed by extensive cuts on the surface and have a depth of 40 to 95% of the thickness of the shaped body.

2. Shaped body according to claim 1, characterized in that the sheets have a cross-sectional shape, which is square, rectangular, acute angle or rounded.

3. Shaped body according to claim 1 or claim 2, characterized in that the sheets have a base width b, width that is 0.5 to 5 mm.

4. Shaped body according to any of claims 1 to 3, characterized in that the sheets are arranged parallel to each other at a distance of 4 to 40 mm.

5. - Process for the isolation of curved faces with heat-insulating insulating material, characterized in that a shaped and evacuated body according to any of claims 1 to 4 having the surface with sheet structure adapts and is fixed to the curved face, and the vacuum is suppressed in at least one layer.

6. Process according to claim 5, characterized in that the shaped body is fixed by lining with a tissue tape, an adhesive tape, a sheet of plastic material or a thin metal sheet, or with cut metal sheet. 1 . - Process according to claim 5, characterized in that the vacuum is suppressed by deteriorating the envelope of the layer with a tool. 8. Process according to claim 5, characterized in that the vacuum is suppressed by partially decomposing the shell of the layer by thermal means. 9. Process according to claim 5, characterized in that the vacuum of at least one layer in the case of multi-layer superstructures is suppressed by subjecting the envelope to mechanical stresses, until the same is torn. 10. Process according to any of claims 5 to 9, characterized in that the vacuum is suppressed in the layer adjacent to the curved face and permanently maintained in at least one layer. 11. Use of a shaped body evacuated according to any of claims 1 to 4 for the isolation of tubes, for example crude oil pipelines and remote heat conductions, engines, turbines and chimneys.