SU1581957A1 - Method of heat insulation of cryogenic objects - Google Patents

Abstract

The invention relates to a cryogenic technique and allows to increase the reliability and quality of thermal insulation, as well as to perform isolation with the possibility of self-compensation. For this, rigid and elastic layers of thermal insulation are arranged alternately in the longitudinal direction, and compression and bonding of the elastic layer is carried out by curing the subsequent foaming rigid layer by setting the stopper at a distance determined by the amount of compression and the coefficient of foaming of the rigid material, while on the opposite end the hard layer forms a convex surface on which, after curing, set the counter concave surface of the elastic layer 3. When applying cryogenic liquid the rigid layers of thermal insulation are cooled and compressed, and the compressed elastic layers expand against pre-deformation and prevent the rigid layers from cracking. 1 hp f-ly, 1 ill.

Description

one

(21) 4410791 / 23-26

(22) 02.03.88

(46) 07/30/90. Bul Number 28

(72) N.A. Schepotko, A.M.Domashenko,

A.G.Lapshin, B.O. Belorusets,

P.V. Kopchenko, V.I. Kuprin,

N.V.Filin and A.S.Guzey

(53) 621.59 (088 8)

(56) USSR Copyright Certificate No. 765592, cl. F 17 C 3/04, 1978.

(54) METHOD OF THERMAL INSULATION OF CRYOGENIC OBJECTS

(57) The invention relates to a cryogenic technique and makes it possible to increase the reliability and quality of thermal insulation,

and also perform isolation with the possibility of autocompensation. For this, the rigid and elastic layers of the heatplate are arranged alternately in the longitudinal direction, and the compression and adhesion of the elastic layer is carried out by curing the subsequent foaming rigid layer by setting the limiter at a distance determined by the amount of compression and the coefficient of foaming of the rigid material, while the convex surface is formed on the opposite end of the rigid layer, on which, after curing, the reciprocal concave surface of the elastic layer is placed. When the cryogenic fluid is supplied, the rigid layers of the thermal insulation cools and compresses, and the compressed elastic layers expand against pre-deformation and prevent the hard layers from cracking. 1 з.п f-ly, 1 ill.

The invention relates to mechanical engineering and can be used when applying thermal insulation to cryogenic pipelines.

The purpose of the invention is to increase the reliability and quality of thermal insulation,

The drawing shows a cryogenic pipeline, the thermal insulation of which is performed by the proposed method.

The heat insulation consists of rigid layers 2 deposited on pipeline 1, between which elastic layers 3 are located. Between layers 2 and 3 limiters 4 are installed. Pipeline 1 together with thermal insulation is enclosed in casing 5. One of the ends of layer 2 has a convex surface 6E the contact surface 7 of layer 3 is concave.

The method is carried out as follows.

A layer of rigid self-foaming material is poured into the cavity between the sliding casing 5 and the pipeline 1, for example, Kriofin-1 phenolformaldehyde foam plastic, the surface 6 is formed on one end of the restrictor 4 and the elastic layer is removed on the surface 6 3 with a mating concave surface 7 made of an elastic material, for example, a 6TH-1 ripore. Then on fix

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The distance H from the edge of the elastic layer 3 is placed around the stopper 4 and the next layer 2 of rigid material is poured into the cavity between the casing 5 and the pipeline 1. The distance H of the installation of limiter 4 is determined by the amount of compression of the elastic layer 2 and the foaming ratio of the rigid material.

For example, the length of an elastic layer made of 6THN1 ripor is 100 mm, the foaming factor of Cryofin-1 is 10. The foaming coefficient is a linear ratio of the liquid phase of the foam to solidified and is determined experimentally for each batch of Cryofin-1 liquid composition. When foaming in a closed volume, the foaming reaction creates a pressure (P) of 3 kgf / cm, which provides compression of the elastic material. Thus, to ensure compression of layer 3 of the 6TH-1 ripor by 20%, it is necessary to set the limiter 4 at a distance (H) of 980 mm. When foaming, layer 2 firmly seizes with internal pipeline 1, the surface of which 4 is covered with an adhesive layer (pressed), which prevents layer 2 from moving along the axis of pipeline 1 and retains the degree of compression of elastic layer 3 after removing limiter 4. At the same time, the non-shaped surfaces of layers 2 and 3 firmly glued with one another without the use of glue. These operations are repeated along the entire length of the cryogenic pipeline 1.

Prior to supplying cryogenic fluid to

pipeline 1, layers 2 and 3 of thermal insulation have ambient temperature. Elastic layer 3 is compressed by 10-20% of the original length. At the moment of supplying the cryogenic liquid to the pipeline I, the walls of the pipeline are rapidly cooled and its dimensions decrease, while the layers 2 adjacent to it also change their length, which leads to their cracking. The elastic layers 3 expand against pre-deformation and compress the rigid layers 2, preventing the cracks from opening. In this case, when the first portions of the cryogenic liquid hit, the lower sections of the metal pipeline 1 and the adjacent layers of thermal insulation are first cooled, which, due to their compression, causes bending

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pipeline 1. For example, a 056 mm pipeline insulated with cryofin-1 foam and a length of 4 m is bent by 34 mm, which would lead to cracking of the upper outer layers 2 of the insulation. The presence of a movable joint of surfaces 6 and 7, formed by layers 2 and 3, allows the pipeline 1 to bend at the moment of supplying the cryogenic liquid without cracking the rigid layer 2 of the foam. As the heat insulating temperature stabilizes, the rigid layer 2 of the material is compressed and the elastic layer 3 of the material expands, which, expanding, prevents opening and cracking in the rigid layers 2 along the entire length of the pipeline 1.

The proposed thermal insulation method eliminates the destruction of thermal insulation, improves reliability and durability by eliminating adhesives and providing self-compensation for the insulation. Thus, no cracks are formed in the heat insulation, its quality and reliability are improved, and therefore the loss of cryogenic fluid is reduced. In addition, the proposed method makes it possible to manufacture an insulation consisting of 9/10 of cheap hard material, Cryofin-1, and to reduce the use of expensive elastic material, ripor 6TH-1, etc.

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Claims (1)

1. A method for insulating cryogenic objects, mainly pipelines, comprising applying layers of thermal insulation from an elastic and rigid foaming material to the pipeline, gluing them together and compressing a layer of elastic material, characterized in that, in order to improve the reliability and quality of thermal insulation, the layers alternate in the longitudinal direction, first a layer of rigid material is poured into the casing, a convex surface is formed on one of its ends and after curing a layer of elastic material is laid on it with the answer concave surface, with compression and gluing during the curing of the subsequent layer of rigid material when installing the limiter on