US3672184A

US3672184A - Apparatus for thermally insulating a body

Info

Publication number: US3672184A
Application number: US883744A
Authority: US
Inventors: Sten Olof Zeilon
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-12-10
Filing date: 1969-12-10
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

A thermal insulation is obtained by producing foam, introducing the foam into the insulating space, collecting the liquid formed upon the collapse of the foam, again transforming said liquid into foam and introducing the foam into the insulating space to replace the collapsed foam.

Description

United States Patent Zeilon [451 June 27, 1972 APPARATUS FOR THERMALLY INSULATING A BODY Inventor: Sten 0101 Zeilon, Glumslov, Sweden Filed: Dec. 10, 1969 Appl. No.: 883,744

US. Cl ..62/324, 165/2 Int. Cl ..F25b 13/00 Field ofSearch.... .."165/1, 2, 105, 107, 108,135, 165/136; 261/DIG, 26, 111, 151; 62/234, 324; 52/2, 743; 2/2.l R; 252/207, 359 E References Cited UNITED STATES PATENTS Glaser ..62/239 Metcalfe ..62/262 3,512,761 5/1970 ORegan et a1. ..261/D1G. 26

FOREIGN PATENTS OR APPLICATIONS 1,121,909 7/1968 Great Britain ..105/! Primary Examiner-Charles Sukalo Assistant Examiner-W. C. Anderson Attorney-McGlew and Toren [5 7] ABSTRACT A thermal insulation is obtained by producing foam, introducing the foam into the insulating space, collecting the liquid formed upon the collapse of the foam, again transforming said liquid into foam and introducing the foam into the insulating space to replace the collapsed foam.

15 Claims, 7 Drawing Figures PMENTEDJUHN 1972 3 672, 1

SHEET 2 OF 2 77 INVENTOR Fl 6.? Stan Olof Zeilon by Mmfm ATTORNEYS APPARATUS FOR THERMALLY INSULATING A BODY The invention is concerned with a method for thermally insulating a body. Said body may be therooms of a building or a house. The invention is also useful for insulating, for example, a greenhouse or a cold storage room. The invention is also useful for insulating articles and goods when being transported in movable containers.

It is an object of the invention to provide at a low cost a heat insulation having a low weight and an excellent insulating capacity. It is another object of the invention to provide a heat insulation which is not combustible and which can absorb an excessive degree 'of heat, for example the heat originating from sun radiation or from a fire in the insulated building. It is another object of the invention to provide an insulating system making it possible to absorb and accumulate the heat originating from the sun or the sky during the day, and to use said accumulated heat for heating the insulated building or house during the night. It is another object of the invention to provide an insulating system in which the insulating agent also works as a heating or cooling agent for transporting the desired heat or cold from a source of heat or cold to the various rooms of a house, for example. Other objects of the invention will be apparent from the following specification.

The method of the invention comprises introducing gas into a solution of a foaming agent in a liquid so as to produce foam, introducing the foam into a space surrounding the body, collecting the liquid formed in the continuous collapsing of the foam, again introducing gas into said liquid to form a new quantity of foam, and again introducing the foam in said space to replace the collapsed foam.

The liquid may be water, containing a surface active agent as foaming agent, such as soap, saponin, protein or a synthetic agent such as sodium alkyl sulphate. The foaming agent should preferably be present in the water in a percentage of 1-2 percent by weight. Another useful liquid is glycol, such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol. Other useful liquids are glycerine and glycol derivatives, such as diethylene glycol ethyl ether. ExamPles of useful surface active agents to be used in glycerine and glycol and glycol derivatives are propylene glycol monostearate, fatty alcohol amine sulphates, such as the compound sold under the trade name Duponol WS, a fatty acid amideethylene oxide condensate, such as the compound sold under the trade name Ethomide HT-lS, sorbitan monostearate, and cetyl alcohol. Thepercentage of the surface active agent in glycerine and glycol and glycol derivatives in preferably 4-5 percent by weight. Mixtures of water and the organic liquids referred to above are also useful, for instance if it is desired to reduce the freezing'point of the liquid below that of water. By selecting the liquid and the surface active agent it is possible to produce a foam having a stability within the range from one minute up to 72 hours. A foam stabilizer may be added to the liquid, if it is desired to produce a foam having an extraordinarily long life-time. If it is desired that the foam shall collapse rapidly, a small quantity of, for EXAMPLE, ether or amyl alcohol may be added to the foam.

The liquid may contain other additives, such as compounds absorbing the visible light or the infra-red or the ultra-violet radiation.

The foam is produced by incorporating a gas, usually air, into the solution of the foaming agent in a way known per se. An example of the foam generator will be illustrated in the drawings.

BRlEF DESCRIPTlON OF THE DRAWING The invention will now be described with reference to the drawings.

FIG. 1 illustrates a tennis hall or a similar building, which is insulated according to the invention.

FIG. 2 illustrates the heat flow through a portion of the wall of the building of FIG. 1.

FIG. 3 illustrates thermal insulation by means of two layers of foam having different temperatures.

FIG. 4 illustrates the heat flow through the wall shown in FIG. 3.

FIG. 5 illustrates the heat insulation of goods in a container.

FIGS. 6 and 7 illustrate the use of a heat pump for increasing the efiiciency of a conventional thermal insulation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The building illustrated in FIG. 1 contains a concrete floor 23. The floor supports a plurality of semi-circular supports 24, which carry a plurality of lengthwise extending supports 25. These supports 25 carry an inner wall 2 consisting of a comparatively rigid, water-tight material. Parallel with and spaced from the inner wall 2 is an outer wall 1 consisting of a penneable material, for example a textile web or a plastic sheet which is porous or has a plurality of small openings. The two

walls

1 and 2 define an insulating space 3. The walls are united at their lower ends by a bottom 5. A tube 26 connects the lower portion of the space 3 with a tank 10. The tank 10 contains an electric heater 7 controlled by a thermostat 13. A tube 8 with a pump 9 extends from the bottom of the tank 10 to a foam generator 6. The foam generator contains a propeller 27 driven by an electric motor 28, a perforated member 29, such as a web or wire netting, and between the propeller and the perforated member a spray nozzle 30 on the upper end of the tube 8. The foam generator communicates through a duct 33 with a distributing tube 11 extending along the top of the building and communicating with the insulating space 3 through a plurality of openings 34. The electric current to the motors for the propeller 27 and the pump 9 is controlled by a switch 12 which is controlled by a pressure gauge 35 actuated by the pressure in the insulating space 3. i

In operation the foaming liquid in the tank 10 is pumped by the pump 9 to the spray nozzle 30, and the liquid is sprinkled onto the perforated member 29. A stream of air is blown, by means of the propeller 27, through the perforated member 29, and the liquid and the air intermix to form foam. The foam flows through the duct 33, the distributing tube 11 and the openings 34 into the insulating space 3. The foam collapses during its downward flow through the space 3. The liquid resulting from the collapsing foam flows along the inner wall 2 down to the bottom 5, and through the tube 26 to the tank 10. The air resulting from the collapsing foam escapes through the permeable wall 1. The liquid collected in the tank 10 is again used for producing foam in the foam generator 6.

The permeable outer wall 1 needs no mechanical support, because the pressure of the foam is sufficient for keeping it supported. The pressure gauge 35 feels the pressure of the foam. If the pressure becomes too high, the pressure gauge actuates the switch 12 to stop the motors driving the propeller 27 and the pump 9. The lifetime of the foam shall be approximately equal to the time required for the foam to flow from the foam generator to the bottom 5 of the insulating space 3.

If desired, the liquid in the tank 10 may be heated by means of the heater 7. Thus, the foam can be given any temperature required for maintaining the desired temperature in the hall or room 4. The thermostat 13 is preferably used for keeping a constant temperature. If desired, cooling means may be provided in the tank 10, in order to maintain the hall or room 4 at a temperature lower than that of the surrounding air.

In the embodiment illustrated in FIG. 1 the air used in the foam generator is taken from the room 4. The used air is replaced by fresh air supplied through air intakes, not illustrated. Alternatively, fresh air may be supplied to the foam generator, and the air released during the collapsing of the foam may be supplied as fresh air to the room 4. For this purpose the inner wall 2 is preferably made gas-permeable, whereas the outer wall 1 is made gas-tight. The air thus entering the room 4 through the permable wall 2 will be comparatively pure, because dust particles and other impurities have been absorbed by the liquid. The air will also have a comparatively high degree of humidity, if the foaming liquid is based upon water. The outer wall 1 may, entirely or partially, consist of a translucent material. This results in the foam being heated by the radiation from the sum or from the sky. Consequently, the liquid in the tank will be heated to some extent. The tank 10 is preferably given such a size that the heat accumulated during the day suffices for supplying heat to the building during the night.

If the building illustrated in FIG. 1 is a greenhouse both

walls

1 and 2 are preferably transparent or translucent. In the daytime the foam generator may be switched 05, allowing a maximum of sunlight to enter the greenhouse. In order to accelerate the collapse of the foam in the morning a small quantity of a foam collapsing agent, such as ether, may be added to the insulating space3. If the outer wall 1 is not self-supporting, or supported by a frame, it will collapse to be supported by the inner wall 2.

FIG. 2 illustrates a section of the wall of the building of FIG. 1 near the top of the wall. It is assumed that the foam flows through the insulating space 3 in the direction of the arrow 27a. It is further assumed that the air outside the building has the temperature whereas the interior 4 of the building has the temperature t which is higher than t,. If the space 3 had been filled with a conventional insulating material, the graph illustrating the temperature in the space 3 would have had the appearance represented by the line 1 Due to continuous drainage of liquid content in the foam in the direction of gravity, represented by arrow 27b, the graph 1 will be distorted so as to take the shape of line 1 The appearance of the distorted graph implies an inherent heat trap effect, reducing the loss of heat from the wall 1 to the air outside thebuilding. The air escaping through the wall 1 will have the temperature 1,. Com sequently, the foam will act as a heat exchanger, recovering the heat content of the air. Similarily, when the temperature t of the interior of the building is lower than temperature 2? of the air outside the building, the drainage of the foam will constitute a cold trap, reducing the loss'of cold from the wall 1 to the air outside the building.

The heat or cold trap effect will have a positive maximum of efiiciency for a horizontal insulating space situated on top of the insulated-body. The efficiency will decrease to zero for vertical spaces and be negative for spaces situated underneath the body. Therefore the invention is particularly useful for the insulation of roofs and sloping walls.

The wall illustrated in FIG. 3 comprises an outer wall member 41, an inner wall member 42, and a middle wall member 14 dividing the wall into an outer insulating space 31 and an inner insulating space 32. The liquid collecting in the bottom of the space 31 is pumped by a pump 91 in a conduit 81 through a heat exchanger 21 to a foam generator 61, in which it is transformed into foam which is supplied to the top portion of the space 31. The liquid collecting in the bottom of the space 32 is pumped by a pump 92 in a conduit 82 through a heat exchanger 22 to a foam generator 62 in which it is transformed to foam which is supplied to the top portion of the space 32. The heat exchangers 21, 22 form parts of a socalled heat pump 38 containing a compressor 17 which propels a condensable gas, such as ammonia, through a condensor 15, and an evaporator 16 in the direction of the arrows. The condensable gas condenses in the condenser 15, and the heat formed as a result of the condensation is transmitted to the heat exchanger 22, which is in heat-exchanging contact with the condenser 15. The condensed gas evaporates in the evaporator 16, and the heat required for the evaporation is taken from the heat exchanger 21, which is in heat-exchanging contact with the evaporator 16.

The result of the operation of the heat pump 38 is that heat is transported from the liquid flowing in the conduit 81 to the liquid flowinG in the conduit 82. Consequently, the foam flowing through the space 31 will have a lower temperature than that flowing through the space v32. This is illustrated in FIG. 4 in which the graph t illustrates the temperature in the section A-A near the top of the wall, and the graph I illustrates the temperature in the section B-B near the bottom of the wall. The fact that the temperature of the foam in the space 3] lies comparatively close to the temperature t of the air outside the building results in a very low loss of heat from the building.

The foams in the

spaces

31 and 32 may be based on different liquids if the middle wall 14 consists of an impermeable material. If it is desired to use one single foaming liquid the middle wall 14 may consist of a permeable material, such as a wire net.

FIG. 5 illustrates the insulation of goods 54, in a container 51. The goods are placed upon an insulating support 50, preferably consisting of a porous plastic, for instance polyurethane, of a type which does not absorb a liquid. The walls of the goods are covered with an impermeable plastic layer 52. A tube 58 extends from the bottom of the container to a foam generator in the top of the container. The tube 58 contains a pump 59 and a heat exchange 57 in which the liquid flowing through the pipe 58 can be cooled or heated, depending on the nature of the goods. The foam generator 70 has a cylindrical shape, and the cylindrical wall 56 consists of a web, a wire net, or the like. The tube 58 enters the foam generator through an opening in its top wall, and the end of the tube is provided with a spray nozzle 71 which sprays the foaming liquid towards the cylindrical wall 56. A wire net 18 defines a space 19 between the top wall of the foam generator and the top wall of the container 51.

In operation the foaming liquid is pumped from a pool 55 of liquid on the bottom of the containerto the foam generator 70. The liquid spray leaving the spray nozzle 71 sucks gas from the space 19 into the foam generator 70. Foam is formed when the liquid and the gas pass through the perforated wall 56. When the space 53 between the goods 54 and the wall of the container 51 has been filled with foam, a pressure difference occurs between the

spaces

53 and 19, owing to the inability of the. foam to penetrate through the netl8. A pressure gauge 73 senses this pressure difi'erence and actuates upon a switch 72 to switch off the current to the motor driving the pump 59.

It has been disclosed, with reference to FIGS. 3 and 4, that a heat pump is useful for reducing the loss of heat from a warmer body to a colder body by creating a temperature difference in two layers of foam, the warmer foam layer being adjacent the warmer body, the colder foam layer being adjacent the colder body. According to a modification of the thermal insulation illustrated in FIGS. 3 and 4 the heat pump is useful for reducing the loss of heat from a Wanner body to a colder body even if the fluids which are in heat exchanging contact with the heat pump do not consist of foam but are gases or liquids. A thennal insulation of this modified type comprises a first space for a fluid, adjacent the colder body, a second space for fluid, adjacent the warmer body, and a heat pump for transporting heat from the first space to the second space.

It is preferred that the fluid is a liquid, because the heat pump operates with a high efficiency when being in heat exchanging contact with liquids. The liquids may be water or any of the other liquids, such as glycol, referred to in the disclosure of foaming liquids.

It is preferred that the first and second spaces are separated by a conventional thermal insulation, such as a layer of mineral wool or porous plastic. Such an insulating layer is preferably also provided between the warmer body and the second space, and between the colder body and the first space.

FIG. 6 illustrates an insulating wall according to the modified embodiment. The wall separates a body 68 of a higher temperature I, from a body 69 of a lower temperature The wall contains two insulating

layers

43, 46 containing mineral wool, for example. A space 44 for a gaseous or liquid is provided between the insulating layers. A similar space 45 is provided on the surface of the layer 46 facing the body 68.

The fluid in the space 44 is circulated by means of a conduit 64 containing a pump 48. The fluid in the space 45 is circulated by means of a conduit 63 containing a pump 47.

A heat pump 65-67 transports heat from the fluid in the conduit 64 to the fluid in the conduit 63. The heat pump may be of any known type, but is illustrated to be a compressoroperated cooling machine, comprising a compressor 67, a condenser 65, and an evaporator 66. The compressor 67 compresses a fluid, such as ammonia, to the effect that the fluid condenses to form a liquid in the condenser 65, which is in heat exchanging contact with the conduit 63. Consequently, the fluid in the conduit 63 is heated. The condensed fluid is evaporated in the evaporator 66 which is in heat exchanging contact with the conduit 64. Consequently, the fluid in the conduit 64 is cooled.

The temperature in the wallis illustrated by the graph 60. The temperature z in the middle of the wall is lower than the temperature in a conventional wall under similar conditions. Therefore, the heat flow through the layer 43 is lower, and the loss of heat from the body 68 to the body 69 is lower. This is true in spite of the fact that the heat flow through the layer 46 is higher than that in a conventionally insulated wall, owing to the fact that the heat flowing through the layer 46 is trapped by the fluid in the space 44, and is recovered in the heat pump 65-67. When used for the insulation of a building, the heat pump will operate in an advantageous temperature range and with a high efficiency, particularly if the fluid circulating through the

spaces

44, 45 is a liquid, such as water. The reduction in heat flow from the body 68 to the body 69 is much larger than the powerrequired for driving the heat pump.

FIG. 7 illustrates an embodiment of the

spaces

44, 45. Two thin sheets 74, 75 having grooves 76, 77, have been combined so that the grooves form parallel channels 79. The portions 78 between the channels have been united by welding. The channels 79 may be far spaced apart if the sheets 74, 75 consist of a material having a good conductivity for heat, such as a metal. If the material of the sheets has a poor conductivity for heat, such as a plastic, the channels should be placed close to each other.

What is claimed is:

1. A thermal insulation between a colder body and a warmer body, comprising a first space for a fluid, adjacent the colder body, a second space for a fluid, adjacent the warmer body, heat pump means for transporting heat from the first space to the second space, and insulating layers between the colder body and the first space, and between the first space and the second space.

2. A thermal insulation between a colder body and a warmer body, comprising (a) a first space for a fluid, adjacent the colder body, (b) a second space for a fluid, adjacent the warmer body, (c) a heat insulating layer between the first space and the second space, and ((1) heat pump means for transporting heat from the first space to the second space, said first and second spaces comprising a plurality of parallel channels defined by two sheets having been united by welding along parallel zones.

3. A device for the thermal insulation of a body, comprising walls defining an insulating space surrounding the body to be insulated, a foam generator, means for transporting the foam from the foam generator to the insulating space, means for collecting the liquid formed in the insulating space upon the continuous collapsing of the foam, and means for transporting said liquid to the foam generator to be again transformed into foam.

4. A device as claimed in claim 3, comprising means for altering the temperature of the liquid.

5. A building having thermal insulation means comprising a double-walled insulation space, a foam generator, means for transporting the foam from the foam generator to the insulating space, means for collecting the liquid formed in the insulating space upon the continuous collapsing of the foam, and meanS for transporting said liquid to the foam generator to be again transformed into foam.

6. A building as claimed in claim 5, comprising a tank for collecting the liquid formed in the insulating space upon the collapsing of the foam, and in said tank means for altering the temperature of the liquid.

7. A building as claimed in claim 5, in which at least one of the walls of the insulating space is permeable to gas, for the release of the gas formed euipon the collapse of the foam.

' 8. A building as claim in claim 5, m which the outer wall of the insulating space consists of a sheet material being supported by the foam.

9. A building as claimed in claim 5, in which the outer wall of the insulating space consists, at least in part, of a translu cent material.

10. A building as claimed in claim 9, in which said outer wall consists, at least in part, of transparent material.

11. A building as claimed in claim 9, in which also the inner wall of the insulating space consists, at least in part, of a translucent material.

12. A building as claimed in claim 9, in which said inner wall consists, at least in part, of transparent material.

13. A building as claimed in claim 5, comprising a partition dividing the insulating space into an outer insulating space and an inner insulating space, a first foam generator for generating foam for the outer insulation space, a second foam generator for generating foam for the inner insulation space, and means for giving different temperatures to the liquids forwarded to the foam generators.

14. A building as claimed in claim 13, in which said means is a heat pump comprising a compressor, a condenser being in heat exchanging contact with one of said liquids, and an evaporator being in heat exchanging contact with the other liquid.

15. A building as claimed in claim 13, in which the partition is permeable to liquid, the liquid being used for producing foam for the outer insulating space being different to that used for producing foam for the inner insulating space.

i i i i

Claims

2. A thermal insulation between a colder body and a warmer body, comprising (a) a first space for a fluid, adjacent the colder body, (b) a second space for a fluid, adjacent the warmer body, (c) a heat insulating layer between the first space and the second space, and (d) heat pump means for transporting heat from the first space to the second space, said first and second spaces comprising a plurality of parallel channels defined by two sheets having been united by welding along parallel zones.

7. A building as claimed in claim 5, in which at least one of the walls of the insulating space is permeable to gas, for the release of the gas formed upon the collapse of the foam.

8. A building as claimed in claim 5, in which the outer wall of the insulating space consists of a sheet material being supported by the foam.

9. A building as claimed in claim 5, in which the outer wall of the insulating space consists, at least in part, of a translucent material.