GB2046865A - Insulation of pipe by multi- stage application of foam - Google Patents
Insulation of pipe by multi- stage application of foam Download PDFInfo
- Publication number
- GB2046865A GB2046865A GB8005589A GB8005589A GB2046865A GB 2046865 A GB2046865 A GB 2046865A GB 8005589 A GB8005589 A GB 8005589A GB 8005589 A GB8005589 A GB 8005589A GB 2046865 A GB2046865 A GB 2046865A
- Authority
- GB
- United Kingdom
- Prior art keywords
- layer
- pipe
- insulation
- foamed
- foam
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000009413 insulation Methods 0.000 title claims abstract description 31
- 239000006260 foam Substances 0.000 title abstract description 19
- 239000010410 layer Substances 0.000 claims abstract description 86
- 229920003023 plastic Polymers 0.000 claims abstract description 32
- 239000004033 plastic Substances 0.000 claims abstract description 32
- 229920002635 polyurethane Polymers 0.000 claims abstract description 14
- 239000004814 polyurethane Substances 0.000 claims abstract description 14
- 239000002184 metal Substances 0.000 claims abstract description 5
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 3
- 239000010959 steel Substances 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 20
- 239000000203 mixture Substances 0.000 claims description 18
- 238000005187 foaming Methods 0.000 claims description 12
- 238000005260 corrosion Methods 0.000 claims description 4
- 230000007797 corrosion Effects 0.000 claims description 4
- 239000011253 protective coating Substances 0.000 claims description 4
- 239000011254 layer-forming composition Substances 0.000 claims 2
- -1 polypropylene Polymers 0.000 abstract description 5
- 229920000573 polyethylene Polymers 0.000 abstract description 4
- 239000011241 protective layer Substances 0.000 abstract description 3
- 239000004743 Polypropylene Substances 0.000 abstract description 2
- 239000000853 adhesive Substances 0.000 abstract description 2
- 230000001070 adhesive effect Effects 0.000 abstract description 2
- 239000002390 adhesive tape Substances 0.000 abstract description 2
- 239000010426 asphalt Substances 0.000 abstract description 2
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 abstract description 2
- 239000004620 low density foam Substances 0.000 abstract description 2
- 230000000704 physical effect Effects 0.000 abstract description 2
- 229920001155 polypropylene Polymers 0.000 abstract description 2
- 239000004593 Epoxy Substances 0.000 abstract 2
- 238000010924 continuous production Methods 0.000 abstract 1
- 230000001681 protective effect Effects 0.000 description 7
- 239000004615 ingredient Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 4
- 229920005830 Polyurethane Foam Polymers 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 239000004088 foaming agent Substances 0.000 description 3
- 239000011496 polyurethane foam Substances 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- 239000004604 Blowing Agent Substances 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 125000005442 diisocyanate group Chemical group 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920005862 polyol Polymers 0.000 description 2
- 150000003077 polyols Chemical class 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- CYRMSUTZVYGINF-UHFFFAOYSA-N trichlorofluoromethane Chemical compound FC(Cl)(Cl)Cl CYRMSUTZVYGINF-UHFFFAOYSA-N 0.000 description 2
- 229940029284 trichlorofluoromethane Drugs 0.000 description 2
- IMNIMPAHZVJRPE-UHFFFAOYSA-N triethylenediamine Chemical compound C1CN2CCN1CC2 IMNIMPAHZVJRPE-UHFFFAOYSA-N 0.000 description 2
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 239000007983 Tris buffer Substances 0.000 description 1
- UKLDJPRMSDWDSL-UHFFFAOYSA-L [dibutyl(dodecanoyloxy)stannyl] dodecanoate Chemical compound CCCCCCCCCCCC(=O)O[Sn](CCCC)(CCCC)OC(=O)CCCCCCCCCCC UKLDJPRMSDWDSL-UHFFFAOYSA-L 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000012975 dibutyltin dilaurate Substances 0.000 description 1
- 229920006334 epoxy coating Polymers 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000004850 liquid epoxy resins (LERs) Substances 0.000 description 1
- 239000013521 mastic Substances 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 235000010981 methylcellulose Nutrition 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000000153 supplemental effect Effects 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
- LENZDBCJOHFCAS-UHFFFAOYSA-N tris Chemical compound OCC(N)(CO)CO LENZDBCJOHFCAS-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L59/00—Thermal insulation in general
- F16L59/14—Arrangements for the insulation of pipes or pipe systems
- F16L59/143—Pre-insulated pipes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/20—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length
- B29C44/22—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length consisting of at least two parts of chemically or physically different materials, e.g. having different densities
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/20—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length
- B29C44/32—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements
- B29C44/322—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements the preformed parts being elongated inserts, e.g. cables
- B29C44/324—Incorporating or moulding on preformed parts, e.g. linings, inserts or reinforcements the preformed parts being elongated inserts, e.g. cables the preformed parts being tubular or folded to a tubular shape
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L59/00—Thermal insulation in general
- F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials
- F16L59/029—Shape or form of insulating materials, with or without coverings integral with the insulating materials layered
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L59/00—Thermal insulation in general
- F16L59/08—Means for preventing radiation, e.g. with metal foil
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L59/00—Thermal insulation in general
- F16L59/14—Arrangements for the insulation of pipes or pipe systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L59/00—Thermal insulation in general
- F16L59/14—Arrangements for the insulation of pipes or pipe systems
- F16L59/147—Arrangements for the insulation of pipes or pipe systems the insulation being located inwardly of the outer surface of the pipe
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Thermal Insulation (AREA)
- Laminated Bodies (AREA)
- Insulators (AREA)
- Flanged Joints, Insulating Joints, And Other Joints (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Molding Of Porous Articles (AREA)
- Motor Or Generator Cooling System (AREA)
- Linear Motors (AREA)
- Details Of Indoor Wiring (AREA)
Abstract
Metal e.g. steel pipe insulated with foamed polyurethane plastic is made in a multi-stage continuous process in which an inner layer of polyurethane plastic is foamed on the pipe and at least partially cured to form low-density foam having high heat insulating capacity, and an outer layer of polyurethane plastic is foamed on the inner layer to provide a foam layer of higher density, the outer layer having a density at least 25% greater than that of the adjacent inner layer, the thickness of the outer layer being 5 to 30% of the total thickness of the foamed insulation. The inner layer may be subdivided into two or more layers having different physical properties. A common protective layer e.g. polythene/butyl adhesive tape, epoxy, heat actuated adhesive or asphalt may be first applied to the pipe. An outer protective layer of paper, butuminous inactive or plastic e.g. polythene, polypropylene or epoxy may be applied. The plastic may be heat shrinkable.
Description
SPECIFICATION
Insulation of pipe by multi-stage application of foam
This invention relates to a method of thermally insulating metal pipe and pertains more specifically to a method of providing a metal pipe with two or more layers of foamed plastic insulation of differing apparent densities and preferably different thermal stabilities, the lowest density foam being adjacent to the surface of the pipe and the highest adjacent to the outer surface of the foamed insulation.
It has hitherto been proposed to insulate pipe by spraying thereon one or more layers of foaming plastic insulation such as polyurethane followed by curing and coating or wrapping the insulation layer with a protective or barrier layer as described for example in
Bauer et al., U.S. Patent 3,480,493. The layer of foam insulation resulting from such a process has normally possessed an apparent density of intermediate value such that it has properties which are a compromise between those required for maximum heat insulation characteristics and those required for maximum strength, crush resistance and abrasion resistance. It has also been proposed in Henderson et al., U.S.Patent 4,094,715 to spray pipe with a foaming liquid composition, then wrap the rising foam with a protective sheet material before the rising foam has completely set so as to increase the density of the foam near its outer-most surface. A major disadvantage of the process is that it is restricted to a spirally wound protective sheet outer layer, which is applied under tension to achieve an apparent increase in the density of the outer layer of the foam.Such a process is difficult to control in commercial operations because the extent of increase in apparent density and the thickness of the high density layer depend upon several different critical factors including temperature of the foaming plastic, speed of foaming of the plastic composition, cure rate of the foaming plastic, time lapse before application of the protective sheet, and the tension applied to the protective sheet during application. All of these factors influence the extent to which the foamed plastic has cured or set before application of the sheet. Moreover, the thickness of the layer of increased density depends upon the thickness and compressibility of the mass of low density foam already present.
The present invention provides a process for applying to a pipe a first layer of foamable polyurethane plastic composition and foaming it in place to form a first layer of foamed plastic having a low apparent density, from 1.5 to 61b/cu.ft. (about 0.024 to 0.096 grams/cu.cm.), then applying over said first layer a second layer of foamable plastic and foaming it in place to form a second layer of foamed plastic having a high apparent density. Because the thickness and density of each layer is independent of the other and can be individually adjusted and controlled, the process of the present invention makes it possible to employ an inner layer having high heat insulation value and low cost together with an outer higher-strength and higher-density, therefore higher-cost layer.The two layers together provide combined properties which are optimal for pipe insulation and protection at minimum total cost.
The extent of difference in density between inner and outer insulating layers for optimum results varies depending upon the diameter of the pipe, the relative thickness of the layers, the minimum strength desired, and the temperature differential between the pipe and the surroundings, among other things. However, in general, the apparent density of the outer layer should be at least 25% greater than that of the inner, and the thickness of the outer layer should be from 5 to 30% of the total thickness of the foam insulation layers. If desired, the inner layer can be subdivided into two or more layers applied in sequence and differing in physical properties between themselves.
In the drawing:
Figure 1 is a view in cross-section showing one embodiment of the invention; and
Figure 2 is a view in cross-section showing another embodiment.
In the embodiment of Fig. 1, metal pipe 10 is provided with an inner layer 12 of low density (2 to 6 Ib/cu.ft. or 0.032 to 0.096 grm/cu.cm.) rigid polyurethane foamed insulation having a thickness from about 1 to about 6 inches (2.54 to 15.24cm.), and a second layer 14 of rigid polyurethane foamed insulation having a density at least 25% greater than that of layer 12 and having a thickness from 5 to 30% of the total thickness of layers 12 and 14 together.
In a preferred embodiment of the invention, the inner layer of foamed insulation differs from the outer layer or layers not only in having a lower apparent density and hence a higher heat insulation capacity, but also in having higher heat resistance, i.e., being stable at higher temperatures, up to 350 F (177 C), than is the outer layer or layers of foamed insulation, which need be stable only up to a temperature of 200 F (93.5 C).
A second embodiment is illustrated in Fig.
2 in which pipe 10, designed to carry hot fluids at temperatures of 300 to 350 F (149 to 177 C), is provided with an inner insulation layer subdivided into a first portion or layer 20 of low density foamed polyurethane insulation formulated to have stability at a temperature as high as 350 F (177 C) and a second portion or layer 22 of approximately the same low density foamed polyurethane but formulated to have stability only at tem peratures up to 200 F (93.5 C). Outer layer 24 of high density foamed polyurethane has a density at least 25% greater than that of either layer 20 or 22 and has a thickness from 5 to 30% of the total thickness of layers 20, 22 and 24.In another embodiment in which pipe 10 is designed to convey cryogenic fluids at very low temperatures of the order of ~200oF (- 129"C), layer 20 is formulated to be semi-rigid instead of rigid to avoid embrittlement and possible cracking during use, while layers 22 and 24 are formulated to be conventionally rigid in nature.
In practicing the method of the present invention, the pipe, which is usually steel, is first heated to remove moisture condensation and cleaned to remove dirt, scale and rust.
Any of the usual procedures for cleaning may be employed such as sand blasting or shot blasting, brushing or the like. If desired, two or more of such procedures may be employed in combination.
In some cases, it may be desirable to provide a corrosion protective coating on the pipe surface before applying the foaming plastic to it, although this is not essential. Any conventional corrosion protective coating may be employed such as wrapped polyethylene/butyl adhesive tape, epoxy coating, heat activated adhesive, or asphalt. The foamable thermoplastic material may be applied directly to the bare pipe or to the surface of any corrosion protective coating previously applied to the pipe. It is usually desirable that the temperature of the pipe be elevated above room temperature, the precise temperature depending upon the nature and composition of the foamable plastic composition. The latter is usually applied in the form of a spray delivered from a spray nozzle as the pipe is rotated and advanced past the various nozzles.Any of a wide variety of formulations for the foamable liquid polyurethane plastic composition may be used depending upon the precise characteristics desired in the end product. A particularly desirable composition is a liquid mixture of ingredients reactable to form a polyurethane and including a conventional foaming agent in an amount sufficient to produce a foam having the desired apparent density, which may be from about 1.5 to about 6 pounds per cubic foot (0.024 to 0.096 grams/cu.cm.). The first layer of foamable liquid is allowed to rise by action of the foaming agent.The thickness of the first layer of foam may vary over a wide range depending upon the same factors discussed above in connection with difference in density of the insulating layers, such as the pipe diameter and the temperature at which the pipe with its contents is designed to operate, and in general may vary from about 1 to about 6 inches (2.54 to 15.24 cm).
The second or outer layer 14 or 24 of foamable liquid plastic composition is then applied to the outer surface of the first foamed insulation layer by spraying in the usual manner on the surface of the rotating and advancing pipe. The second layer may be applied to the first before or after the latter has been cured, and even before foaming of the latter has been completed. Preferably it is applied before the first layer is cured. In one embodiment, the formulation of the second foamable plastic composition is different from the first only in the amount of foaming agent used and is adjusted so as to provide a foamed plastic insulation layer having an apparent density at least 25% higher than that of the first layer and a thickness from 5 to 30% of the total thickness of both layers together.In another embodiment, the outer layer 14 or 24 may have a lower heat resistance than the inner or greater rigidity or both.
The total thickness of foamed insulation as well as the thickness of the inner layer (about 1 to about 6 inches or about 2.54 to 15.24 cm.) can be varied depending upon the temperature differential between the contents of the pipe and the surroundings of the pipe, the pipe diameter, and the apparent density of the foam, among others. For a temperature difference of 75 to 270 F (41.5 to 150 C), a thickness of about 1 to about 6 inches (2.54 to 15.24 cm.) normally suffices. In general, the greater the temperature difference between the pipeline and the ground, the thicker the insulation should be. For example, cryogenic industries normally use 3 to 6 inches (7.6 to 15.24cm.) of polyurethane foam because of larger temperature differentials.For hot oil lines, the differential is usually from 100 to 160 F (55.5' to 89 C). For hot oil pipelines, the thickness would normally be from 1 to 2.5 inches (2.54 to 6.4cm.). A pipe for conducting molten sulphur will be provided with 2 1 /2-3 inches (6.3 to 7.65cm.) of foamed insulation, the inner layer 12 or 20 of which is formulated to have high heat resistance, i.e., to be stable at temperatures up to 300 F (149 C). A pipe for hot oil will when buried in the ground normally require a foam thickness of 2 inches (5.1 cm.) or less.
Polyurethane foam has an extremely low K factor, of the order of 0. 13 Btu/sq. ft/hr F/in. (about 6.94 X 10-6grm-cal/sq.cm/ sec/ C/cm.), in contrast to a K factor of about 0.39 for glass foam. For example, in the case of a polyurethane foam having an apparent density of 3 Ib/cu.ft. (0.048grm- cu.cm.), a layer 2 inches (5.1cm.) thick on a pipe 6 inches (15.24cm.) in diameter operating at a temperature differential of 125 F (69.4 C) results in a heat loss (or gain) of 5.8
Btu/hr/sq.ft (about 43.7 X 10-6 grm-cal/ sec/sq.cm.).
There follows a suitable recipe for making a satisfactory rigid foam:
Parts By
Ingredient Weight
Crude MDI 115
Polyol A 100
Silicone oil 1
Triethylene diamine 0.5
Dibutyl tin dilaurate 0.1
Trichloromonofluoro
methane 35
Tris(2-ch loroethyl)
phosphate 10
All of the ingredients except the diisocyanate are preblended, the diisocyanate being mixed in immediately prior to foaming and spraying in conventional equipment to form a rigid foam having an apparent density of 1.8
Ib/cu. ft. (0.029 grm/cu.cm.). Decreasing the proportion of trichloromonofluoromethane blowing agent leads to increase in density.
Increase in solids in the foregoing recipe, as by adding 30 parts of methyl cellulose without increase in blowing agent also increases apparent density. Increased heat resistance of the foam is achieved by conventional formulating techniques and selection of ingredients, as for example by reacting aromatic aminecontaining compounds with the remaining ingredients as described in Wiedermann et al.
U.S. Patent 3,909,465; increased resistance to friability, also desirable for the outer layer of foam, can also be achieved by selection of polyol ingredients as described for example in
Fuzesi et al. U.S. Patent 3,928,257 and in
Alexander U.S. Patent 3,928,258.
Any desired outer layers or coatings may be applied over the outer foamed insulation layer.
For example, the outer foamed insulation layer can be provided with a wrapped or extruded protective or moisture barrier layer of paper or plastic, e.g., polyethylene or polypropylene, an envelope or wrapped layer of heat-shrinkable plastic which is shrunk in place to conform to the foamed insulation, a coating of liquid epoxy resin cured in place or a coating of bituminous mastic, or a layer of any other conventional protective material. However, because of the tough crush resistant and abrasion resistant nature built into the outermost layer of foamed polyurethane plastic in the present invention, any supplemental outer protective layer need in most cases provide only a barrier against puncture and moisture penetration.
Claims (10)
1. A method of providing pipe with at least one inner layer and an outer layer of foamed plastics insulation, which comprises applying to said pipe at least one inner layerforming foamable plastics composition, foaming the or each composition to form a respective layer of foamed plastics insulation having an apparent density of from 1.5 to 6.0
Ibs/cu.ft (0.024 to 0.096 g/cc), applying to the surface of the last applied inner layer an outer layer-forming foamable plastics composition and foaming and curing the outer-layer forming composition to form an outer layer of rigid foamed plastics composition having an apparent density at least 25% greater than that of the, or any, inner layer and having a thickness of from 5 to 30% of the total thickness of the layers.
2. A method as claimed in Claim 1 and further comprising previously applying to the pipe one or more further inner layer-forming compositions to form one or more further inner layers.
3. A method as claimed in Claim 1 or 2, wherein the pipe is a metal pipe, such as a steel pipe, and further comprising initially applying a corrosion protective coating to the pipe.
4. A method as claimed in any one of the preceding claims, wherein the foamable plastics compositions are polyurethane compositions.
5. A method as claimed in any one of the preceding claims, wherein the innermost layer of foamed plastics insulation is stable at temperatures of up to 350 F (177 C) and the outer layer or layers are stable only at temperatures of up to 200 F (93.5 C).
6. A method as claimed in any one of the preceding claims, wherein the innermost layer is rigid.
7. A method as claimed in any one of
Claims 1 to 5, wherein the innermost layer is semi-rigid.
8. A method of providing pipe with foamed plastics insulation, substantially as herein described with reference to Fig. 1 or
Fig. 2 of the accompanying drawings.
9. A pipe when insulated by a method as claimed in any one of the preceding claims.
10. The features as herein disclosed, or their equivalents, in any novel selection.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US2079279A | 1979-03-15 | 1979-03-15 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2046865A true GB2046865A (en) | 1980-11-19 |
| GB2046865B GB2046865B (en) | 1983-06-15 |
Family
ID=21800609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8005589A Expired GB2046865B (en) | 1979-03-15 | 1980-02-19 | Insulation of pipe by multi-stage application of foam |
Country Status (31)
| Country | Link |
|---|---|
| JP (1) | JPS55133951A (en) |
| AR (1) | AR225305A1 (en) |
| AT (1) | AT377227B (en) |
| AU (1) | AU532291B2 (en) |
| BE (1) | BE882206A (en) |
| BR (1) | BR8001461A (en) |
| CA (1) | CA1160914A (en) |
| CH (1) | CH635182A5 (en) |
| CS (1) | CS220765B2 (en) |
| DD (1) | DD149955A5 (en) |
| DE (1) | DE3006545C2 (en) |
| DK (1) | DK151913C (en) |
| EG (1) | EG14165A (en) |
| ES (1) | ES490303A0 (en) |
| FR (1) | FR2451261A1 (en) |
| GB (1) | GB2046865B (en) |
| GR (1) | GR67219B (en) |
| HU (1) | HU178150B (en) |
| IE (1) | IE49291B1 (en) |
| IT (1) | IT1193927B (en) |
| MX (1) | MX150570A (en) |
| NL (1) | NL186831C (en) |
| NO (1) | NO161208C (en) |
| NZ (1) | NZ193125A (en) |
| PH (1) | PH15434A (en) |
| PL (1) | PL133428B1 (en) |
| PT (1) | PT70943A (en) |
| SE (1) | SE447414B (en) |
| SU (1) | SU1351520A3 (en) |
| YU (1) | YU66780A (en) |
| ZA (1) | ZA80949B (en) |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2120747A (en) * | 1982-05-20 | 1983-12-07 | Hepworth Plastics Ltd | Pipes for pipelines |
| US5470515A (en) * | 1991-06-05 | 1995-11-28 | Bayer Aktiengesellschaft | Rotational molding process for insulating pipes |
| WO2000073695A1 (en) * | 1999-05-26 | 2000-12-07 | Thermotite As | Steel tube with heat insulation for subsea pipelines and method of producing same |
| US6171533B1 (en) | 1994-10-25 | 2001-01-09 | Cerntube Pty Ltd. | Multipurpose composite tubing |
| RU2182868C1 (en) * | 2001-05-31 | 2002-05-27 | Закрытое акционерное общество Научно-производственное предприятие "МАЯК-93" | Method for manufacture of coextruded multilayer pipe, device for its realization and pipe so produced |
| RU2276756C1 (en) * | 2004-12-17 | 2006-05-20 | Владимир Аркадьевич Устюгов | Heat insulated pipe for heat and/or water supply systems |
| RU2326291C1 (en) * | 2006-12-28 | 2008-06-10 | Ольга Владимировна Устюгова | Thermal-insulated pipe for heating and/or water-supply systems of building and structures |
| WO2008116625A1 (en) | 2007-03-26 | 2008-10-02 | Rehau Ag + Co | Plastic tube |
| ITMI20090939A1 (en) * | 2009-05-27 | 2010-11-28 | Dow Brasil Sa | PIPES FOR DEEP WATER USE |
| EP2263849A3 (en) * | 2009-06-18 | 2012-02-29 | Lambda One Isoliertechnik GmbH | Method and unit for manufacturing precast insulating bodies |
| US20130327466A1 (en) * | 2012-06-08 | 2013-12-12 | Pellegrino J. Pisacreta | Insulated tubing |
| CN103557404A (en) * | 2013-11-06 | 2014-02-05 | 北京豪特耐管道设备有限公司 | Production method of heat insulation pipeline and heat insulation pipeline adopting method |
| CN103587215A (en) * | 2013-11-11 | 2014-02-19 | 镇江市高等专科学校 | Foam material heat-fusion laminating equipment for multi-degree-of-freedom floating pipe |
| CN103968161A (en) * | 2014-05-23 | 2014-08-06 | 张楠 | Rubber hose |
| WO2014122278A1 (en) * | 2013-02-08 | 2014-08-14 | Logstor A/S | Method for producing an insulated pipe in corrugated casing |
| CN104295809A (en) * | 2014-11-05 | 2015-01-21 | 广西金盛科技发展有限公司 | PVC drainage pipe |
| CN106917933A (en) * | 2016-03-28 | 2017-07-04 | 齐克先 | A kind of prefabricated direct-buried thermal insulation pipe of material hole with reinforcing chip and manufacture method |
| CN107020774A (en) * | 2017-04-05 | 2017-08-08 | 绵阳高新区三阳塑胶有限责任公司 | A kind of multi-layer multi heat preserving and insulating material and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| NL8005255A (en) * | 1980-09-19 | 1982-04-16 | Wavin Bv | PLASTIC TUBE PART PROVIDED WITH A PLASTIC FOAM INSULATION LAYER. |
| FI77102C (en) * | 1981-05-25 | 1989-01-10 | Kabel Metallwerke Ghh | Process for producing a heat insulated conduit |
| AU590713B2 (en) * | 1984-06-07 | 1989-11-16 | Asahi Chemical Industry Co. Ltd. | Heat insulating structures for low-temperature or cryogenic pipings |
| DE3530187C2 (en) * | 1985-08-23 | 1994-12-01 | Marquet & Cie Noel | Method and device for producing thermally insulated conduits |
| JPH0814359B2 (en) * | 1985-09-02 | 1996-02-14 | 株式会社日本メデイクス | Tube for cryogenic piping of beauty and medical equipment |
| DE3534241A1 (en) * | 1985-09-26 | 1987-04-02 | Rheinhold & Mahla Gmbh | Process for producing an insulation of in situ polyurethane foam for pipelines, containers and columns |
| DE4421817A1 (en) * | 1994-06-22 | 1996-01-04 | Bayer Ag | Insulating of tubes, esp. for long-distance heat supply |
| NO962627L (en) * | 1996-06-20 | 1998-01-19 | Per Ludvig Engesaeter | Anti-corrosion, thermal storage, thermally resistant and thermally insulating coating / casing |
| RU2152553C1 (en) * | 1998-11-24 | 2000-07-10 | Центральный научно-исследовательский институт им. акад. А.Н. Крылова | Heat-insulating coat for horizontal pipe line |
| RU2274798C2 (en) * | 2004-05-07 | 2006-04-20 | Открытое акционерное общество "ОКБ Сухого" | Method and device for heat insulation of article |
| EP1909018B1 (en) * | 2006-10-05 | 2014-08-20 | Georg Fischer Rohrleitungssysteme AG | Pipe connection with thermal insulation and procedure for the manufacture of the pipe connecting part |
| EA018041B1 (en) * | 2010-07-22 | 2013-05-30 | Общество С Ограниченной Ответственностью "Смит-Ярцево" | Pipeline heat insulation |
| RU2629102C2 (en) * | 2011-11-28 | 2017-08-24 | Басф Се | Continuous method of manufacturing isolated pipes, isolated pipe, device for manufacturing this isolated pipe and application of said device |
| JP6080404B2 (en) * | 2012-06-28 | 2017-02-15 | 旭有機材株式会社 | Piping cover |
| CN105972329A (en) * | 2016-05-25 | 2016-09-28 | 安徽普氏生态环境工程有限公司 | Novel water supply pipe |
| CN109506064A (en) * | 2018-12-25 | 2019-03-22 | 哈尔滨朗格斯特节能科技有限公司 | Hard polyaminoester spraying winds prefabricated direct-buried heat insulation elbow with high density polyethylene (HDPE) |
| CN110402870B (en) * | 2019-09-02 | 2021-09-07 | 福建亚通新材料科技股份有限公司 | Pipeline for deep sea cultivation |
| IT201900020781A1 (en) * | 2019-11-11 | 2021-05-11 | Ecotech S R L | Thermo-insulated tube |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4820967B1 (en) * | 1967-05-11 | 1973-06-25 | ||
| NL6903871A (en) * | 1969-03-13 | 1970-09-15 | ||
| US3657036A (en) * | 1969-10-02 | 1972-04-18 | Nat Gypsum Co | Method for production of rigid polyurethane articles |
| US3644168A (en) * | 1970-06-12 | 1972-02-22 | Upjohn Co | Varied density polyisocyanurate foam structure |
| US3814659A (en) * | 1971-02-01 | 1974-06-04 | Upjohn Co | Novel compositions |
| US3802948A (en) * | 1971-06-09 | 1974-04-09 | Hitachi Shipbuilding Eng Co | Thermal insulation for cryogenic containers |
| US3782998A (en) * | 1971-11-30 | 1974-01-01 | Atlantic Richfield Co | Method of insulating cold substrates and the insulated substrates |
| GB1357765A (en) * | 1971-12-03 | 1974-06-26 | Bauakademie Ddr | Insulated pressure pipe |
| US3979818A (en) * | 1972-05-30 | 1976-09-14 | Shaw Pipe Industries Ltd. | Method of thermally insulating pipe |
| BE885751Q (en) * | 1976-08-27 | 1981-02-16 | Kendall & Co | METHOD AND APPARATUS FOR APPLYING A FOAMABLE LIQUID TO A CYLINDRICAL OBJECT |
| JPS5472558A (en) * | 1977-11-21 | 1979-06-11 | Sekisui Plastics | Pipe cover |
-
1980
- 1980-02-19 GB GB8005589A patent/GB2046865B/en not_active Expired
- 1980-02-19 ZA ZA00800949A patent/ZA80949B/en unknown
- 1980-02-21 DE DE3006545A patent/DE3006545C2/en not_active Expired
- 1980-02-26 AT AT0105380A patent/AT377227B/en not_active IP Right Cessation
- 1980-02-28 FR FR8004467A patent/FR2451261A1/en active Granted
- 1980-02-28 AU AU55973/80A patent/AU532291B2/en not_active Ceased
- 1980-02-29 HU HU8080473A patent/HU178150B/en not_active IP Right Cessation
- 1980-03-01 EG EG114/80A patent/EG14165A/en active
- 1980-03-05 GR GR61351A patent/GR67219B/el unknown
- 1980-03-07 CS CS801594A patent/CS220765B2/en unknown
- 1980-03-10 JP JP2927380A patent/JPS55133951A/en active Pending
- 1980-03-11 YU YU00667/80A patent/YU66780A/en unknown
- 1980-03-12 DD DD80219617A patent/DD149955A5/en not_active IP Right Cessation
- 1980-03-12 CA CA000347490A patent/CA1160914A/en not_active Expired
- 1980-03-12 SE SE8001923A patent/SE447414B/en not_active IP Right Cessation
- 1980-03-12 PT PT70943A patent/PT70943A/en unknown
- 1980-03-12 IT IT20535/80A patent/IT1193927B/en active
- 1980-03-12 BR BR8001461A patent/BR8001461A/en unknown
- 1980-03-13 PL PL1980222668A patent/PL133428B1/en unknown
- 1980-03-13 BE BE0/199781A patent/BE882206A/en not_active IP Right Cessation
- 1980-03-13 ES ES490303A patent/ES490303A0/en active Granted
- 1980-03-13 NO NO800730A patent/NO161208C/en unknown
- 1980-03-13 MX MX181541A patent/MX150570A/en unknown
- 1980-03-14 SU SU802896301A patent/SU1351520A3/en active
- 1980-03-14 IE IE532/80A patent/IE49291B1/en unknown
- 1980-03-14 NL NLAANVRAGE8001541,A patent/NL186831C/en not_active IP Right Cessation
- 1980-03-14 CH CH202180A patent/CH635182A5/en not_active IP Right Cessation
- 1980-03-14 DK DK111480A patent/DK151913C/en not_active IP Right Cessation
- 1980-03-14 PH PH23773A patent/PH15434A/en unknown
- 1980-03-14 AR AR280328A patent/AR225305A1/en active
- 1980-03-14 NZ NZ193125A patent/NZ193125A/en unknown
Cited By (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2120747A (en) * | 1982-05-20 | 1983-12-07 | Hepworth Plastics Ltd | Pipes for pipelines |
| US5470515A (en) * | 1991-06-05 | 1995-11-28 | Bayer Aktiengesellschaft | Rotational molding process for insulating pipes |
| US6171533B1 (en) | 1994-10-25 | 2001-01-09 | Cerntube Pty Ltd. | Multipurpose composite tubing |
| WO2000073695A1 (en) * | 1999-05-26 | 2000-12-07 | Thermotite As | Steel tube with heat insulation for subsea pipelines and method of producing same |
| GB2365096A (en) * | 1999-05-26 | 2002-02-13 | Thermotite As | Steel tube with heat insulation for subsea pipelines and method of producing same |
| GB2365096B (en) * | 1999-05-26 | 2003-04-09 | Thermotite As | Steel pipe with heat insulation for deep-sea pipelines and method of producing it |
| RU2182868C1 (en) * | 2001-05-31 | 2002-05-27 | Закрытое акционерное общество Научно-производственное предприятие "МАЯК-93" | Method for manufacture of coextruded multilayer pipe, device for its realization and pipe so produced |
| RU2276756C1 (en) * | 2004-12-17 | 2006-05-20 | Владимир Аркадьевич Устюгов | Heat insulated pipe for heat and/or water supply systems |
| RU2326291C1 (en) * | 2006-12-28 | 2008-06-10 | Ольга Владимировна Устюгова | Thermal-insulated pipe for heating and/or water-supply systems of building and structures |
| WO2008116625A1 (en) | 2007-03-26 | 2008-10-02 | Rehau Ag + Co | Plastic tube |
| ITMI20090939A1 (en) * | 2009-05-27 | 2010-11-28 | Dow Brasil Sa | PIPES FOR DEEP WATER USE |
| WO2010136268A1 (en) * | 2009-05-27 | 2010-12-02 | Dow Global Technologies Inc. | Pipes for deep water applications |
| EP2263849A3 (en) * | 2009-06-18 | 2012-02-29 | Lambda One Isoliertechnik GmbH | Method and unit for manufacturing precast insulating bodies |
| US20130327466A1 (en) * | 2012-06-08 | 2013-12-12 | Pellegrino J. Pisacreta | Insulated tubing |
| WO2014122278A1 (en) * | 2013-02-08 | 2014-08-14 | Logstor A/S | Method for producing an insulated pipe in corrugated casing |
| US9862127B2 (en) | 2013-02-08 | 2018-01-09 | Logstor A/S | Method for producing an insulated pipe in corrugated casing |
| CN103557404A (en) * | 2013-11-06 | 2014-02-05 | 北京豪特耐管道设备有限公司 | Production method of heat insulation pipeline and heat insulation pipeline adopting method |
| CN103557404B (en) * | 2013-11-06 | 2015-11-25 | 北京豪特耐管道设备有限公司 | The insulated piping that a kind of production method of insulated piping and employing the method are produced |
| CN103587215A (en) * | 2013-11-11 | 2014-02-19 | 镇江市高等专科学校 | Foam material heat-fusion laminating equipment for multi-degree-of-freedom floating pipe |
| CN103968161A (en) * | 2014-05-23 | 2014-08-06 | 张楠 | Rubber hose |
| CN104295809A (en) * | 2014-11-05 | 2015-01-21 | 广西金盛科技发展有限公司 | PVC drainage pipe |
| CN106917933A (en) * | 2016-03-28 | 2017-07-04 | 齐克先 | A kind of prefabricated direct-buried thermal insulation pipe of material hole with reinforcing chip and manufacture method |
| CN107020774A (en) * | 2017-04-05 | 2017-08-08 | 绵阳高新区三阳塑胶有限责任公司 | A kind of multi-layer multi heat preserving and insulating material and preparation method thereof |
| CN107020774B (en) * | 2017-04-05 | 2019-02-22 | 绵阳高新区三阳塑胶有限责任公司 | A kind of multi-layer multi heat preserving and insulating material and preparation method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |