GB2118268A

GB2118268A - Insulated pipes

Info

Publication number: GB2118268A
Application number: GB08209692A
Authority: GB
Priority date: 1982-04-01
Filing date: 1982-04-01
Publication date: 1983-10-26
Also published as: GB2118268B

Abstract

Pipe insulation for a pipe (1) consists of hollow cylindrical lengths (2) of insulation material clad in a metallic skin (5). The joints between adjacent lengths of insulation are sealed by means of a strip of deformable sealant (6) held against the joint by a metallic circumferential strip (8) in turn secured in position by a metallic clamping strip (10). <IMAGE>

Description

SPECIFICATION Improved pipe insulation This invention relates to improved pipe insulation, metallic cladding for such pipe insulation and to pre-insulated pipe sections including such pipe insulation.

At present, cladding of pipe insulation is carried out on site, calcium silicate or other insulation being applied in half annular pieces bound together and then covered by metallic cladding. During erection it is often necessary to support the half annular pieces of insulation by external devices of a temporary nature, such as jigs. It is also difficult on site to ensure that the metallic cladding is applied tightly enough to the insulation. If it is applied tightly enough, it forms a homogeneous mass with the solid insulant spreading and absorbing localised or point blows or impacts harmlessly in the insulation. On the other hand if the metallic cladding is not applied tightly enough the force of any blow or impact is not spread or absorbed and is localised in its effect, tending to crack and damage the insulation.At the joint between adjacent cladding sections the normal practice is simply to overlap the adjacent ends which does not give a watertight joint.

According to the present invention there is provided a modular insulation section for the insulation of a pipe comprising a layer of insulation material clad in a metal, and sealing means to seal between the joint between two juxtaposed insulation sections. Preferably the modular sections are cylindrical.

The inner layer of insulation material may be stepped at each end and a deformable sealant is provided between the confronting ends of adjacent sections. The sealing means may comprise a deformable sealing strip and a circumferential metallic strip for holding the sealing strip in watertight engagement with the ends of the metallic cladding sheath which preferably do not overlap one another.

The insulation should preferably be in lengths of about 1 metre to allow easy handling. The insulation material may be moulded into the metallic sheath to form a composite unit or the cladding may simply be applied off site under factory conditions so as to improve quality control and to make the application of the cladding that much easier.

The invention also includes metallic cladding for pipe insulation comprising individual lengths of cladding arranged to be disposed about an insulated pipe, deformable sealing means for positioning at the joint between two juxtaposed lengths of cladding, and means for retaining the sealing means in watertight relation with the ends of the metallic lengths of cladding.

Preferably, each length of cladding has both ends swaged, the sealing means being a sealing strip which lies between the respective ridges of the swaged ends of the adjacent pipes so as to seal around the joint. The retaining means may comprise a circumferential metallic strip held in position by at least one metallic band which also serves to compress the deformable sealing strip.

According to another aspect of the invention there is provided a pre-insulated pipe length having an inner layer of insulation material and an outer metallic sheath, sealing means being provided to seal between the joint between two juxtaposed pre-insulated pipe lengths.

The advantages of the various different aspects of the present invention are that: (a) it enables complete factory assemblies of pre-insulated pipe to be made; (b) it enables site application of pre-clad insulation to be carried out with better control of the final assembly and at lower cost; (c) it ensures that the joints between the adjacent lengths of insulation are watertight whilst allowing differential expansion; and (d) it requires a minimum number of jigs and temporary supports during erection as the hollow cylinders of metallic clad insulation can be threaded on to the pipe as it is erected. In this way the insulation is supported by the pipe it is to insulate and does not require the support from external devices used in the conventional application of insulation on site.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic sectional side elevation of a pipe with metallic clad insulation in accordance with the invention; Figure 2 is an enlarged view of the joint shown in Fig. 1; and Figure 3 illustrates an alternative arrangement.

In the drawings a pipe 1 is insulated by means of hollow cylindrical lengths 2 of calcium silicate insulation material. The ends of each length of the insulation material are stepped or staggered at 3 and preferably a deformable sealant 4 is applied between the joints as shown. The insulation material 2 is protected from damage by means of metallic cladding skin 5 which encases the insulation material.

In order to seal the joints between adjacent lengths of insulation 2 and cladding 5 a strip of deformable sealant 6 is placed around the joint between the insulation. The metallic cladding 5 is formed in hollow cylindrical lengths and each length of cladding has a circumferential ridge or swage 7 formed one at each end. The metallic cladding lengths 5, as shown in Figs. 1 and 2 are positioned adjacent one another and over the respective adjacent ridges 7 of two juxtaposed lengths of cladding is placed a metallic circumferential strip 8 which has two grooves 9 correspond ing to the shape of the ridges 7 in the ends of the cladding 5. The metallic circumferential strip 8 is in turn held in position by a tight metallic band or clamping strip 10 which also serves to compress the strip of deformable sealant 6 against the cladding lengths 5.

The alternative arrangement disclosed in Fig. 3 is similar to that shown in Figs. 1 and 2 except that the circumferential strip 8 totally encloses the area of the joint, the respective ridges 7 and grooves 9 not cooperating with one another. Moreover the strip 8 is held in position by two spaced metallic bands 11 instead of the single band shown in the first embodiment. This design has advantages in that it makes allowance for, and can compensate for, any dimensional deviation arising from the manufacture of insulation and its metallic cladding lengths 5. In this alternative design the ridges defined by the grooves 9 in the circumferential strip 8 locate the clamping bands 11. It is not necessary to ensure that the circumferential strip 8 fits tightly against the ridges 7 in the insulation's metallic cladding 5 so long as the strip 8 fits tightly against the circumferential deformable sealant strip 6.

Claims

1. A modular insulation section for the insulation of a pipe comprising an inner layer of insulation material, an outer layer of metal or metallic cladding, and sealing means for sealing between the joint of two juxtaposed insulation sections.

2. A modular insulation section according to claim 1 wherein the section is cylindrical in shape.

3. A modular insulation section according to claim 1 or 2 wherein the inner layer of insulation material is stepped at each end.

4. A modular insulation section according to any one of claims 1 to 3 wherein the sealing means comprises a deformable sealing strip and a circumferential metallic strip for holding the sealing strip in watertight engagement with the ends of the cladding of two juxtaposed insulation sections.

5. A modular insulation section according to any one of the preceding claims wherein the insulation material is moulded into the metallic cladding.

6. A modular insulation section according to any of claims 1 to 4 wherein the insulation material is moulded to shape and thereafter clad in metallic material.

7. Metallic cladding for pipe insulation comprising individual lengths of cladding arranged to be disposed about an insulated pipe, deformable sealing means for position ing at the joint between two juxtaposed lengths of cladding, and means for retaining the sealing means in substantially watertight relation with the ends of the metallic lengths of cladding.

8. Metallic cladding according to claim 7 wherein each individual length of cladding has both ends swaged, the sealing means being a sealing strip which lies between the respective ridges of the swaged ends of the adjacent lengths so as to seal around the joint.

9. Metallic cladding according to claim 7 or 8 wherein the retaining means comprises a circumferential metallic strip held in position by at least one metallic band which also serves to compress the deformable sealing strip.

10. A pre-insulated pipe length having an inner layer of insulation material and an outer metallic sheath, and including sealing means to seal the joint between two juxtaposed preinsulated pipe lengths.

11. A modular insulation section substantially as hereinbefore described with reference to the accompanying drawings.

12. Metallic cladding substantially as hereinbefore described with reference to the accompanying drawings.