METHOD AND DEVICE FOR DRAINING HUMIDITY FROM INSULATION

Abstract: There is referred to a method and a device for drawing off humidity, such as condensation fluid, from insulation layer (34) around apparatuses, pipe lines (30) and the like. The method is characterised in that a hollow body (10), such as a sleeve, is arranged in a passage (38) in the insulation material (34), and where a number of openings in the wall portion of the hollow body or the sleeve (10) communicate with the insulation (34) and at least one opening communicates with the surroundings outside the insulation layer, whereby condensation fluid (40) can be drawn off from the insulation layer to the surroundings via the hollow body in the form of the sleeve (10).

Description: Method and Device for draining humidity from insulation. The present invention relates to a method and device for drawing off humidity, such as condensed humidity (condensation fluid) , from insulation layers around apparatuses, pipe conduits and the like, as are indicated in the introduction to the subsequent claims 1 and 8, respectively. The invention thus has to do with a novel construction of an insulation system for draining or drawing off condensation fluid. The method and device are especially intended for application for draining any moisture/condensation from insulation materials which are arranged around apparatuses and pipe lines in which fluids, such as liquids and gas are conveyed or stored, or in apparatus where processes occur which involve being able to form condensation on the surface of the apparatus or the pipe line. Such condensation is formed on the hot side of a boundary surface between a cold fluid and a hot gas fluid when the latter includes a condensable gas. In the present instance, when a colder fluid is conveyed through a pipe line while the surroundings represent the hotter fluid, the pipe outer wall constitutes said boundary surface (the hot side) . It is usual to arrange a mantle of insulation around pipe lines which convey fluids. In addition to the insulating effect, the insulation layer also provides protection against mechanical damage. Usually the mantle of insulation comprises a sleeve-shaped layer of the insulation material itself which surrounds the pipe. The outer side of the insulation material is usually covered by a thinner cover layer in the form of weather-protecting cover cloth, that is to say a metal or plastic layer. The cover layer can be water-tight so that water, from rain and the like, does not penetrate into the insulation itself. The drawback with the sealed cover layer is however that it also involves condensation being able to be simultaneously locked inside the insulation, which can entail the occurrence of corrosion on the pipe surfaces. Furthermore the insulating effect of the insulating material is reduced as a result of the accumulated moisture . If the fluid has a higher temperature than the surrounding air the insulation contributes to prevent heat losses from the pipe line. And correspondingly, if the fluid has a lower temperature, the insulation prevents a rise in temperature of the pipe fluid. When air having a temperature higher than the temperature of the pipe fluid comes into contact with the pipe wall, a portion of the air humidity will condense against the colder pipe surface. This problem with condensation which is confined within the insulation material applies of course not only in connection with pipe lines, but also in connection with fluid-carrying apparatuses, such as tanks, containers and the like (for example in connection with refrigerating plants) where these are insulated in a similar fashion so as to prevent heat transfer between the fluid within the tank or the container and the surroundings . In the following the expression drain is employed so as to cover being able to vent the insulation of moisture- containing air, and being able to draw off liquid state condensation water, by employing the device according to the invention. It is an object of the present invention to provide a method and a device which can prevent or reduce the problems which arise in connection with such condensation within pipe line insulations. It is also an object of the present invention to provide a device which can also contribute to a lower venting of any humidity (such as steam-formed humidity) in the insulation itself. This means that condensation, both in liquid and steam form can escape the insulation. The method according to the present invention is characterised by the features which are evident from the characterised portion of the following claim 1, and preferred embodiments are indicated in the dependent claims 2 - 7. The device according to the present invention is characterised by the features which are evident from the characterised portion of the following claim 8, and preferred embodiments are indicated in the dependent claims 9 - 13. The device according to the present invention is defined as a hollow space-forming body, and according to the most preferred embodiment this body is designed as a sleeve having a through duct. The duct itself thus constitutes the above-defined hollow space, while the one of the duct openings of the sleeve constitutes the said at least one opening which forms a connection between the hollow space and the surroundings outside the insulation layer. The invention shall now be explained further with reference to the accompanying Figures, wherein: Figure 1 shows a perspective view of a construction of the drain device according to the invention. Figure 2 shows a cross-section of the drain sleeve according to Fig. 1. Figures 3 and 4 show respectively a perspective view and a cross-section of an insulated pipe where the drain sleeve comes into use. As is evident from Figure 1, the drain sleeve 10 comprises an elongate pipe or a sleeve which forms a hollow internally elongate and through passage 12. In the one end portion the sleeve 10 comprises a flange or base portion 14. Along the length of the whole sleeve 10 there are arranged a number of openings or bores through the wall of the sleeve. The openings can form a regular or irregular pattern. On the outer side of the sleeve there are further arranged a number of elevations 18. The elevations have a form like barbs which cause the sleeve to be slidably displaced relative to a woven or other surface, the one way, but will have a tendency to stick on slide displacement the other way. The elevations can thus comprise studs 18 projecting outwardly from the surface of the sleeve which face outwards and backwards in a direction towards the flange 14. In Figure 1 the drain sleeve is illustrated in the form of a pipe having a circular cross-section, but the drain sleeve can have other cross-sections, for example it can be more oval or polygonal . The drain sleeve 10 according to the invention is preferably made of plastic, and it can be made in alternative ways, such as by injection moulding, or by extrusion with subsequent working in order to form inter alia the openings in the pipe wall. It is an advantage to employ a sleeve material which has a low heat conductivity. In order to be able to adjust the length of the drain sleeve according to the current need, the sleeve is divided into a number of sleeve sections 20a, 20b, 20c. Each sleeve section 20a, 20b, 20c is separated from adjacent sleeve sections by a groove or a depression which is arranged around the periphery of the sleeve, and which functions as a fissure or attenuation line) . The grooves 22 are formed by the wall thickness of the sleeve in this portion being somewhat less than in the remaining sleeve portion. A sleeve section can be readily separated from the sleeve by cutting off along a groove. The sleeve illustrated in Figure 1 can have a total length of 100 mm.. For each 1 cm. a groove can be designed and by cutting off according to need the precisely suitable drain sleeve can be produced, that is to say completely down to a length of 20 mm.. As a cutting tool there can be employed a conventional sharp knife, illustrated at 24. According to a preferred embodiment the outer end of the sleeve which is situated outside the insulation comprises a dome-shaped (convex) end portion having a centrally disposed opening hole which has smaller transverse dimensions than the internal cross-section of the sleeve, and through which opening condensation water can freely flow outwards from the sleeve. In Figure 2 there is illustrated a cross-section of the sleeve seen from above. The passage 12, the openings 16, the sleeve wall, the base-forming flange 14 and the rows of barbs 18 are evident from Figure 2. In Figures 3 and 4 there are shown a cross-section and a partial longitudinal section of an insulated pipe, for example a steel pipe, where the drain sleeve is well suited for use. According to an example the pipe 30 conveys a fluid in its internal space 32. On the outside of the pipe 30 there is surroundingly arranged an insulation 34 having a given layer thickness, and an outer cover layer (a mantle) 36 is arranged coveringly on the outside of the insulation. The drain sleeve 10 according to the invention shall now be employed for draining out condensation water which lies in the insulation, and especially completely inside at the surface of the pipe. First an opening is made in the cover layer, and by means of a suitable tool a passage 38 is now made through the insulation material 34 forwards towards the pipe wall. The passage through the pipe wall has a somewhat smaller diameter than the diameter of the sleeve. Now the drain sleeve 10 is cut so that it has the correct length and reaches almost forward to the outer wall of the pipe 30. The end of the sleeve is thrust into the mouth of the duct 38 through the cover layer, and the sleeve is inserted into the duct until the flange 14 halts the inward movement of the sleeve in that it pushes against the outer surface of the cover layer. During the insertion the insulation material is forced somewhat to the side, and the barbs are infiltrated in the adjacent fibres of the insulation material. Thereby the sleeve cannot fall out of the passage by itself. Now the sleeve is mounted, and any occurring condensation water and/or moist air can flow into the duct 12 through the holes 16 through the wall, and condensation water can run along the inside of the sleeve towards its mouth and out as drops, illustrated at 40 in Figure 3. For the condensation water to be able to run out by the force of gravity, the drain sleeve is preferably installed according to the invention from below through the insulation material and upwards towards the overlying pipe wall . In order to obtain a sufficient diversion of condensation, a number of such drain sleeves are installed in a corresponding manner in the insulation in a regular or irregular pattern along the pipe 30. In order to obtain a general venting of moisture from the insulation, it is also possible to install such drain sleeves around the whole periphery of the insulation/pipe. Since the installation of a sleeve can to a certain degree in itself reduce the ability to insulate of the insulation layer, this circumstance, that is to say how tightly the installed sleeves are placed, must therefore be considered precisely in each individual case. The drain sleeve can now remain standing as a permanent drain sleeve in the insulation of the pipe, and uniformly draw off condensation from the insulation material . In that condensation water can now be removed by means of a single drain sleeve which at the same time will involve a certain drying up of the insulation, the danger of the attack of corrosion is heavily reduced on the pipe material 30. Besides the insulating effect of the insulation material will be greatly enhanced when it is now kept in a drier and airier condition. The invention is not to be limited to applying the special design of a pipe or a sleeve for drawing off condensation from the insulation. Thus there can generally be used a hollow space-forming body, such as is defined in the dependent claims, and which can have a number of openings in the wall for the admission of condensation to the hollow space, and at least one opening which can release the condensation further outwards to the surroundings. This means that the body can have many alternative external forms. For example the body can be rectangular or polygonal . However a pipe or sleeve shape will be the most practical and preferred form of the present invention.

Claims: Patent Claims 1. Method for drawing off humidity, such as condensation fluid, from an insulation layer around apparatuses, pipe lines and the like, characterised in that a hollow body is arranged in a passage in the insulation material, and where a number of openings in the wall portion of the hollow body communicate with the insulation and at least one opening communicates with the surroundings outside the insulation layer, whereby the humidity can be drawn off from the insulation layer to the surroundings via the hollow body. 2. Method in accordance with claim 1, characterised in that a sleeve with a through duct is used as the hollow body, and where a number of openings in the wall portion of the sleeve form the fluid connection between the duct and the insulation so that the condensation fluid can be drawn off through the duct to the surroundings. 3. Method in accordance with claim 2, characterised in that the sleeve is installed in the insulation so that the one sleeve end is arranged adjacent to the surface of the apparatus/pipe line itself, while the other end projects ending out approximately in the boundary region between the surroundings and the surface of the insulation. 4. Method in accordance with one of the preceding claims, characterised in that the length of the sleeve is adapted to the layer thickness of the insulation material. 5. Method in accordance with one of the preceding claims, characterised in that a sleeve is installed one end of which comprises a stop flange which is adapted, during installation of the sleeve, to impact against the outer surface of the insulation material. 6. Method in accordance with one of the preceding claims, characterised in that a sleeve is installed the outer surface of which comprises anchoring means, especially in the form of barbs, which prevent the sleeve from sliding out from the insulation layer after it is mounted. 7. Method in accordance with one of the preceding claims, characterised in that for drawing off liquid- formed fluid from the insulation, the sleeve is installed from below and upwards in the insulation material. 8. Device of an insulation system for drawing off humidity, such as condensation fluid, from an insulation layer around apparatuses, pipe lines and the like, characterised by a hollow space-forming body which is adapted to be arranged in the insulation layer, the wall portion of which body comprises a number of openings so as to form a connection between the hollow space and the insulation, and at least one opening for forming a connection between the hollow space and the surroundings outside the insulation layer. 9. Device in accordance with claim 8, characterised in that the hollow body is a sleeve with a through duct, and where a number of openings in the wall portion of the sleeve form a fluid connection between the duct and the insulation so that the condensation fluid can be drawn off into and further through the duct to the surroundings . 10. Device in accordance with one of the claims 8 - 9, characterised in that one end of the sleeve comprises a stop flange which is adapted, during installation of the sleeve, to impact against the outer surface of the insulation material. 11. Device in accordance with one of the claims 8 - 10, characterised in that the outer surface of the sleeve comprises anchoring means in the form of barbs so as to prevent the sleeve from sliding out from the insulation layer after it is mounted. 12. Device in accordance with claim 8, characterised in that the sleeve is divided into a number of sections, and that the length of the hollow body can be cut down by removing one or more of the sections. 13. Device in accordance with claim 12, characterised in that the sleeve is divided into a number of removable sections by means of groove or attenuation lines .

Inventors: VIKANES LARS HOGNE, VIKANES, LARS, HOGNE
Applicants: PHIL JOHANNESEN LARS, VIKANES LARS HOGNE, PHIL-JOHANNESEN, LARS, VIKANES, LARS, HOGNE
Application year: 1998
Main classification: F16L58
IPC codes: F16L55, F16L59