WO2007003191A1

WO2007003191A1 - Method and system for detecting a leakage in an object

Info

Publication number: WO2007003191A1
Application number: PCT/DK2006/000314
Authority: WO
Inventors: Ole Mejnert Kristensen
Original assignee: Viking Life Saving Equipment A/S
Priority date: 2005-06-30
Filing date: 2006-06-07
Publication date: 2007-01-11
Also published as: WO2007003191A8

Abstract

The present invention relates to a method and a system for detecting a leakage in an object, which object is in- flated during the detecting, said object being made of a material which at least is substantially impermeable to gases, said object comprising an outer surface having a first temperature. The system comprises means for sealing of the object so that it can be inflated, means for in-flating the object using a gas having a second temperature, said second temperature being different from said first temperature, and means for detecting a leakage of gas through the material of the object by identifying the temperature difference between the first and the second temperatures.

Description

METHOD AND SYSTEM FOR DETECTING A LEAKAGE IN AN OBJECT

Field of the Invention

The present invention relates to a method and a system for detecting a leakage in an object, which object is inflated during the detecting, said object being made of a material which at least is substantially impermeable to gases, said object comprising an outer surface having a first temperature.

The present invention furthermore relates to a test kit for detecting a leakage in life-saving equipment.

Background Art

It may have severe consequences if inflatable objects or watertight suits have deterioration or even leakages or holes in the material they are made of, espe- cially if the objects are being used in connection with life-saving equipment.

In the prior art when leakage or deterioration in the material, the strength and water tightness of seams and closures are to be detected in objects, they are nor- mally inflated and subsequently tested in water or by soapsuds .

For instance in the case that a immersion suit are to be tested the method may be as follows, a suitable head piece, fitted with means to inject air into the suit, are inserted into the face orifice of the suit and secured so as to minimize leakage around the face seal. If the suit is fitted with detachable gloves and or boots, the wrist and or cuffs are sealed. In the case of a water test the suit is submerged in water and the suit is then inflated to given pressure. If leak, the leak will be revealed by the propagation of bubbles. The leaking areas are marked and the suit will be dried and repaired. This method have the disadvantages of being i) very time-consuming, ii) furthermore due to the fact that the entire suit are being submerged into a water vessel the test area takes up a lot of space, iii) also the subsequently drying is time-consuming and if many suits or objects are to be tested this furthermore occupies a lot of space, and iv) the suits or objects may be packed or further processed before they are completely dry, which may degrade the material of the suits or objects over a period of time.

In case that a soap test is being used the suit is inflated to a given pressure and the suit is covered with a soapy water solution containing enough soap to produce bubbles. If leak, the leak will be revealed by the propagation of bubbles. The leaking areas are marked, the suit is cleaned with fresh water and the suit will be dried and repaired. This method have also a numerous disadvan- tages : i) being very time-consuming both what concerns the testing but also the subsequently washing of the soap, ii) if the soap not is completely removed from suits or objects, detergents may be present on the suits or objects which may damage the material of the suits or objects over a period of time; iii) also the subsequently drying is time-consuming and if many suits or objects are to be tested this furthermore occupies a lot of space, iv) the suits or objects may be packed or further processed before they are completely dry, which may degrade the material of the suits or objects over a period of time, and v) if the soap not have been washed completely of it will discolour the object, which provides a visual not appealing effect to the object. Other methods for testing an object for leakages or deteriorations are known such as inflating the objects with different gases (e.g. ammonia hydroxide or Carbon Monoxide) , which may be detected if the gas leak through the material of the object. Another method is to test the suits in a dark room wherein the suits are being illuminated so that light penetration is detected. However, the last method have the disadvantage that the light penetration will occur in many materials and textiles even with- out being leaky.

Summary of the Invention

An object of the present invention is to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More specifically, it is an object to provide a method and a system for detecting a leakage in an obj ect .

It is also an object of the present invention to provide a method and a system which not is time-consuming in relation to post-testing drying and cleaning.

The above objects, together with numerous other objects, advantages and features, which will become evident from the below description, are accomplished by a solution in accordance with the present invention by a method for detecting a leakage in an object, which object is inflated during the detecting, said object being made of a material which at least is substantially impermeable to gases, said object comprising an outer surface having a first temperature, said method comprising the steps of: -sealing of the object so that it can be inflated,

-inflating the object using a gas having a second temperature, said second temperature being different from said first temperature, and -detecting a leakage of gas through the material of the object by identifying the temperature difference between the first and the second temperatures .

The above mentioned objects are furthermore accom- pushed by a solution in accordance with the present invention by a system for detecting a leakage in an object, which object is inflated during the detecting, said object being made of a material which at least is substantially impermeable to gases, said object comprising an outer surface having a first temperature, said system comprising

-means for sealing of the object so that it can be inflated,

-means for inflating the object using a gas having a second temperature, said second temperature being different from said first temperature, and

-means for detecting a leakage of gas through the material of the object by identifying the temperature difference between the first and the second temperatures. Hereby, a expedient method and system for detecting a leakage in an object is obtained, which is less time- consuming than the known methods .

^■ The matter is by identifying the temperature difference between the temperature of the escaping gas and the temperature of the outer surface of the object a leakage or a deterioration of the material of the object may easily be revealed and marked. Hereinafter, the leakage may be repaired using known methods and the object can at once be further processed or packed due to the fact that no water or soap are being used, thus, subsequently drying and cleaning is not necessary. The term "outer surface" is in this context to be construed as being the opposite side of the gas containing side, i.e. the inflated chamber.

According to the invention, the object may be a suit.

Advantageously, the gas may be air.

In a preferred embodiment according to the invention the object may be life-saving equipment. The term "life- saving equipment" is in this context to be construed as being maritime life-saving equipment, such as liferafts, chutes, MOB, suits, but also protective suits to be used for instance within the chemical industry.

According to the invention, an infrared heat scanning device may be used to detect the temperature differ- ence. In an expedient embodiment according to the invention, the infrared heat scanning device may comprise an infrared camera. By using an infrared camera in connection with the infrared heat scanning device it is obtained that the temperature difference between the tem- perature of the escaping gas and the temperature of the outer surface easily may be detected. Furthermore, by using this technology it is obtained that even small temperature differences may be detected. Test have shown that temperature differences as low as 0.05 degree C may be detected, however, it is obvious that the higher the temperature difference is the higher the accuracy is.

Advantageously, a display device may be arranged, said display device being adapted to display a heat image of the outer surface of the object on which the infrared camera is directed.

In a preferred embodiment according to the invention the system may comprise means for heating or cooling the outer surface of the object. The matter is the outer sur- face of the equipment is heated or cooled so that the surface temperature is higher or lower than the temperature of the gas contained in the object, i.e. a more detectable temperature difference is obtained. In yet a preferred embodiment according to the invention the system may comprise means for heating or cooling the gas used to inflate the object. The matter is the temperature of the gas used to inflate the object is heated or cooled so that the temperature of the gas is higher or lower than the temperature of the outer surface of the object, i.e. a more detectable temperature difference is obtained.

In a preferred embodiment according to the invention the object may be covered by a cover and the first tem- perature is the general surface temperature of the cover and the second temperature is the surface temperature of the cover in the area where gas are leaking in case of a leakage in the object.

In an expedient embodiment according to the inven- tion the cover is made of a gas-permeable textile.

In a further expedient embodiment according to the invention the cover is a damp cover.

By using a cover it is obtained that the temperature difference between the surface temperature of the cover and the temperature of the cover in the area where gas are leaking from the object in case of a leakage is more reliably on the infrared heat scanner, especially when it comes to object produced by a material with high thermal conductivity. The temperature picture on an infrared camera will be more visibly with a damped cover.

The material of the cover is advantageously produced of an elastic textile, and furthermore advantageously of a material were the inside doesn't damp the object.

According to the invention the object may be a watertight suit, an immersion suit, a diver suit, a chemical suit, an inflatable raft, an inflatable dinghy, an inflatable chute, an inflatable lifebuoy, an inflatable life jacket, an inflatable tyre, or the like.

Advantageously, the material of the object may be made of a coated textile, a laminated textile, a folio, or a combination thereof. The invention furthermore relates to a test kit for detecting a leakage in life-saving equipment, said test kit comprising an infrared heat scanning device having an infrared camera.

Brief Description of the Drawings

The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings, which for the purpose of illustration show some non-limiting embodiments and in which

Fig. 1 shows a leakage test according to the invention of a suit, and

Fig. 2 shows a leakage test according to the invention of an inflatable liferaft. All the figures are highly schematic and not necessarily to scale, and they show only parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested.

Description of Preferred Embodiments

In Fig. 1 is a suit 1 shown which are to be tested for a leakage. The suit 1 is inflated during the detecting, and is made of a material which is at least substan- tially impermeable to gases . Advantageously, the material is made of a coated textile, a laminated textile, a folio, or a combination thereof. It may for instance be made of polyethylene, polyvinyl chloride (PVC) , neoprene (CR) , chlorinated polyethylene (CPE) , chloropel, butyl rubber, natural rubber, nitrile, poly vinyl alcohol (PVA) bytyl rubber, poly urethane rubber (PU) , nomex, coated polyester or coated polyamide products or a combination thereof . The suit 1 comprises an outer surface 2 having a first temperature. According to the invention is the suit sealed of (not shown) so that it can be inflated. Hereinafter is the suit inflated by means of for instance a compressor, pump or the like. The suit 1 is inflated preferably by using air, however, other gases may also be used. Furthermore, an air-drier (not shown) may be connected to the means for inflating the suit. The gas used for inflating the suit 1 has a second temperature, which are different from said first temperature. If the suit 1 have any leakages or holes it is detected by the gas escapes through the material of the suit by identifying the temperature difference between the first and the second temperatures. This detection is in this embodiment carried out by using an infrared heat scanning device 4, which comprises a infrared camera 5 and a display device 6.

During the test the infrared camera 5 is directed against the suit 1, which is inflated, and is moved over the entire outer surface of the suit for identifying any leakages. A leakage is identified if the infrared camera observes a difference of the temperature. The heat image of the outer surface may be viewed on the display device 6. The matter is that the outer surface of the suit radi- ates electromagnetic energy which is a function of its surface temperature. The infrared camera converts the radiated heat from the outer surface into an electrical signal. It is this signal which may be displayed on the display device 6 in form of the heat image. If a leakage is identified during the test this will be displayed on the display device by an area which is lighter or darker (in a grey scale with continuous contrast ranging from black to white) than the surrounding area. Normally areas of higher temperatures appear lighter and areas of lower temperature appear darker. If an lighter or darker area is identified this is marked (for subsequently repair) and the detecting is continued.

Advantageously, the outer surface of the suit may be heated or cooled so that the surface temperature is higher or lower than the temperature of the gas contained in the suit, i.e. a higher temperature difference is obtained. Also the temperature of the gas used to inflate the suit may be heated or cooled by means of a device 7 so that the temperature of the gas is higher or lower than the temperature of the outer surface 2 of the suit 1.

In Fig. 2 an inflated liferaft 10 is shown. The lif- eraft 10 consist two inflated chambers 11, 12 and a can- opy 13. In case the inflated chambers 11, 12 are to be detected for a leakage the procedure as described above in connection with Fig. 1 is essentially being used.

In this embodiment an infrared camera 5 is also being used and the heat image of the outer surface of the chambers 11, 12 is being displayed on the display device 6 as described above.

According to the invention the infrared camera may be moved across the outer surface of the object which it is directed towards, for instance being a handheld camera. In another embodiment according to the invention the position of the camera may be fixed, in this embodiment it is the object which is moved and rotated in front of the camera .

Furthermore, the display device may expedient be integrated in the infrared camera.

Although the invention above has been described in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims .

Claims

1. A method for detecting a leakage in an object (1; 10) , which object (1; 10) is inflated during the detect- ing, said object (1; 10) being made of a material which is at least substantially impermeable to gases, said object (1; 10) comprising an outer surface (2) having a first temperature, said method comprising the steps of: -sealing of the object (1; 10) so that it can be in- flated,

-inflating the object (1; 10) using a gas having a second temperature, said second temperature being different from said first temperature, and -detecting a leakage of gas through the material of the object (1; 10) by identifying the temperature difference between the first and the second temperatures.

2. A method according to claim 1, wherein the object is life-saving equipment.

3. A method according to claim 1 or 2, wherein the object is a suit.

4. A method according to any of the preceding claims, wherein the gas is air.

5. A method according to any of the preceding claims, wherein heating or cooling of the outer surface (2) of the object (1; 10) is performed.

6. A method according to any of the preceding claims, wherein heating or cooling of the gas used to inflate the object (1; 10) is performed.

7. A method according to any of the preceding claims, wherein an infrared heat scanning device (4) is used to detect the temperature difference.

8. A method according to claim 7, wherein the infrared heat scanning device (4) comprises an infrared camera (5) .

9. A method according to any of the claims 1-8, wherein the object (1; 10) is covered by a cover and the first temperature is the general surface temperature of the cover and the second temperature is the surface temperature of the cover in the area where gas are leaking in case of a leakage.

10. A method according to claim 9, wherein the cover is made of a gas-permeable textile.

11. A method according to any of the claims 9 or 10, wherein the cover is a damp cover.

12. A system for detecting a leakage in an object (1; 10), which object (1; 10) is inflated during the detecting, said object (1; 10) being made of a material which at least is substantially impermeable to gases, said object (1; 10) comprising an outer surface (2) having a first temperature, said system comprising -means for sealing of the object (1; 10) so that it can be inflated,

-means (3) for inflating the object (1; 10) using a gas having a second temperature, said second temperature being different from said first temperature, and -means for detecting a leakage of gas through the material of the object (1; 10) by identifying the temperature difference between the first and the second temperatures.

13. A system according to claim 12, wherein the object (1; 10) is life-saving equipment.

14. A system according to claim 12 or 13, wherein the object is a suit.

15. A system according to claim 12 to 14, wherein the gas is air.

16. A system according to any of the claims 12 to

15, wherein an infrared heat scanning device (4) is used to detect the temperature difference.

17. A system according to claim 16, wherein the in- frared heat scanning device (4) comprises an infrared camera (5) .

18. A system according to claim 17, wherein a display device (6) is arranged, said display device (6) being adapted to display a heat image of the outer surface (2) of the object (1; 10) on which the infrared camera (5) is directed.

19. A system according to any of the claims 12 to 18, wherein the system comprises means for heating or cooling the outer surface (2) of the object (1; 10) .

20. A system according to any of the claim 12 to 19, wherein the system comprises means for heating or cooling the gas used to inflate the object (1; 10) .

21. A system according to any of the claim 12 to 20, wherein the system comprises a cover for covering the object (1; 10) and the first temperature is the general surface temperature of the cover and the second temperature is the surface temperature of the cover in the area where gas are leaking in case of a leakage.

22. A system according to claim 21, wherein the system comprises means for damping the cover.

23. A system according to any of the claims 12 to

22, wherein the object is a watertight suit, an immersion suit, a diver suit, a chemical suit, an inflatable raft, an inflatable dinghy, an inflatable chute, an inflatable lifebuoy, an inflatable life jacket, an inflatable tyre, or the like.

24. A system according to any of the claims 12 to

23, wherein the material of the object is made of a coated textile, a laminated textile, a folio, or a combination thereof.

25. A test kit for detecting a leakage in life- saving equipment, said test kit comprising an infrared i heat scanning device (4) having an infrared camera (5) .

26. Use of an infrared heat scanning device (4) for detecting a leakage in life-saving equipment.