CA2151962A1 - Flexible sensor tube - Google Patents
Flexible sensor tubeInfo
- Publication number
- CA2151962A1 CA2151962A1 CA002151962A CA2151962A CA2151962A1 CA 2151962 A1 CA2151962 A1 CA 2151962A1 CA 002151962 A CA002151962 A CA 002151962A CA 2151962 A CA2151962 A CA 2151962A CA 2151962 A1 CA2151962 A1 CA 2151962A1
- Authority
- CA
- Canada
- Prior art keywords
- medium
- flexible sensor
- sensor tube
- tube
- flexible
- 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.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
- G01M3/22—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
Abstract
The invention relates to a flexible sensor tube (3, 13) for determining the concentration curve of a medium along a path. Provision is made for a flexible tube (1) of a material which has good permeability to the medium to be completely provided on the inside with a thin coating (2) of a material having poor permeability to the medium. A flexible tube (6) of a material having good permeability to the medium may also be coated on the inside with a material which is impermeable or has poor permeability to the medium, a narrow strip (6a) extending in the longitudinal direction of the flexible tube (6) being left free. In addition, a band (8, 9, 14), which consists of a material impermeable or having poor permeability to the medium, can be bent into the shape of a trough, while a slot-like aperture remains free. The slot-like aperture is here closed by a strip (8a, 10, 15) which consists of a material having good permeability to the medium and which extends in the longitudinal direction of the band (8, 9, 14).
Description
, ,~ lS19fi?. ,,~
~:E3ff TRANSL~UON
Flexible sensor tube The invention relates to a flexible sensor tube for determ;n;ng the concentration curve of a medium along a path. The invention also relates to a method of determ; n; ng the concentration curve of a medium along a path with the aid of a flexible sensor tube of this kind.
A flexible sensor tube of this kind can be used for monitoring pipes, tanks or garbage dumps.
A flexible sensor tube and an apparatus for operating it are known from DE-PS 24 31 907. With its aid it can be ascertained whether a medium is present in the vicinity of the flexible sensor tube. In addition, it is possible to determine the point on the flexible sensor tube where the medium encounters the flexible sensor tube. A concentration curve over the length of the flexible sensor tube can be produced. The flexible tube is permeable to the medium to be detected. A pump is arranged at one end of the flexible tube. With the aid of this pump, individual volumes of a conveying medium can be conveyed through the flexible tube one after the other at intervals of time. A suitable conveying medium is a gas, particularly air. In this way the flow passes through the flexible tube at regular intervals of time, that is to say with a constant frequency, for a conveying period in each case. A sensor sensitive to the medium to be detected is provided at the other end of the flexible tube. Between each two conveying periods the pump remains switched off for a diffusion period, which is distinctly longer than a conveying period. If a medium which is to be detected comes into the vicinity of the flexible tube, it penetrates into the latter within a diffusion period of this kind and is brought to the sensor within a conveying period by the next volume of conveying medium.
Since the conveying medium flows at a known speed, the point where the medium has passed into the flexible tube between two pumping operations can be accurately deter-mined from the difference between the time when the pump is switched on and that when the sensor responds. In addition, the amount of medium that has penetrated can be determined.
From EP-0 175 219 B1 a pipe is known which can be used as a flexible sensor tube in the manner described.
This pipe contains a tubular pipe which is impermeable to the medium to be detected and which has individual apertures. This pipe of impermeable material can be surrounded by a pipe of a permeable material. It is also possible for only the apertures in this pipe of impermeable material to be closed by a permeable material. During its conveyance through the pipe the medium which has diffused into the latter from outside can diffuse out of the pipe again only to a very limited extent while it is being conveyed through the pipe, since the inner wall of the pipe is for the most part impermeable. The production of a hollow pipe of this kind is very expensive, since the impermeable pipe has to be provided with a number of apertures, particularly bores.
The object on which the invention is based is that of providing a flexible sensor tube which works reliably in the determination of the concentration curve of a medium along a path and in addition can be produced quickly and in a simple manner. The intention is also to specify a method of determining the concentration curve of a medium along a path with the aid of a flexible sensor tube of this kind.
The first object is achieved in a first embodi-ment of the invention in that a flexible tube of a material having good permeability to the medium is completely 2151~2 _ - 3 -provided on the inside with a thin coating of a material having poor permeability to the medium.
The advantage is thereby achieved that the medium reaching the flexible sensor tube from the outside always encounters a material which has good permeability and can therefore easily penetrate into said material. From that point an amount of medium sufficient for detection overcomes the thin coating of material having poor permeability and passes into the interior of the flexible sensor tube. From there the medium is practically unable to pass out of the flexible sensor tube through the wall of the latter. This is due to the fact that said thin coating of the material having poor permeability to the medium bounds the interior space of the flexible sensor tube. Because of the relatively fast conveyance of the medium in the flexible sensor tube, the medium has no time to penetrate again into the thin coating to any noteworthy extent. Consequently, it cannot pass to the outside from the flexible tube to any noteworthy extent.
It is thereby ensured that the measurements made are not falsified.
The material having poor permeability absorbs vapor molecules only to a very slight extent. In addition, it has low affinity for nonpolar molecules, which for example include hydrocarbons. It is precisely such substances that frequently have to be detected.
The advantage is therefore achieved that on its path from the outside into the flexible sensor tube the medium can overcome the thin coating within the diff-usion period, whereas from the interior of the flexiblesensor tube it can scarcely penetrate into the coating within the conveying period, 80 that it remains trapped in the flexible sensor tube. Owing to the fact that practically no medium which has penetrated into the flexible sensor tube is lost during its conveyance, the concentration curve can be determined very accurately.
2151S5~
-_ - 4 -With the flexible sensor tube in question the advantage is in particular achieved that said tube can be produced quickly with simple means, since no apertures have to be formed in it.
5The coating of the flexible sensor tube can be effected by processes of precipitation from a gas phase, lacquering processes or immersion processes. It is also possible to insert an inner flexible tube, which is subsequently pressed against the inner surface by expansion of said inner tube.
The thickness of the coating of material having poor permeability amounts for example to between 100 ~m - and 800 ~m. Such a thin coating is not a significant obstacle for a large amount of the medium which has penetrated into the relatively thick wall of the flex-ible sensor tube of material having good permeability.
Nevertheless, it prevents the penetration of the medium from the inside into the wall of the flexible sensor tube.
20In a second embodiment the object is achieved in accordance with the invention in that a flexible tube of a material having good permeability to the medium is coated on the inside with a material which is impermeable or has poor permeability to the medium, while a narrow strip exten~;ng in the longitudinal direction of the flexible tube is left free.
The advantage is thereby gained that at the uncoated strip a particularly large amount of medium can pass from the outside into the flexible sensor tube. This is assisted by the fact that in the material having good permeability the medium can pass to the strip having particularly good permeability, even if it should have penetrated at a different point. The medium which has arrived in the flexible sensor tube can however scarcely leave the latter, because the strip having good permeability is very small in comparison with the entire inner surface of the flexible sensor tube. Still less medium can _ - 5 -leave the flexible sensor tube again if, in6tead of being of material having poor permeability, the coating consists of impermeable material. Only the free strip is then available.
The strip has for example a width of 0.1 mm to 2 mm. With such a narrow strip the advantage is gained that almost no medium can leave the flexible tube again.
Leaving the strip free, the flexible tube is for example coated with a coating of a thickness between 1 mm and 5 mm. This coating contributes toward the mechanical stability of the flexible sensor tube.
The flexible tubes of the first and second embodiments can for example have a circular or polygonal, for example rectangular, cross-section.
In a third emboA; -nt the object is achieved in accordance with the invention in that a band, which consists of a material impermeable or having poor permeability to the medium is bent into the shape of a trough, leaving free a slot-like aperture, and in that the slot-like aperture is closed by a strip, extending in the longit~;n~l direction of the band, of a material having good permeability to the medium.
In this embodiment also the penetrated medium is to a large extent trapped in the flexible sensor tube.
The slot-like aperture has for example a width between 0.1 mm and 2 mm. The band may for example be 1 mm to 5 mm in thickness. The mechanical stability of the flexible sensor tube is thereby ensured.
The band bent into the shape of a trough or channel may for example have a circular or polygonal cross-section.
All flexible sensor tubes according to the invention are in particular distinguished in that they can be produced quickly in a simple manner. Complete coating and also coating with a strip left free can easily be achieved. A flexible sensor tube having a strip consisting of a different material than the remainder of the tube is also easy to produce.
If the flexible sensor tube has a polygonal cross-section having two faces parallel to one another, it can be inserted particularly well into a space which is to be monitored and which is bounded by two parallel seals, for example sheets. The parallel faces of the flexible sensor tube can in that case lie against the seals, so that the flexible sensor tube serves as a spacer between the seals.
Seals of this kind may be component parts of a device, known from DE-OS 41 09 520, for sealing and monitoring a volume, which may be a garbage dump.
The material having good permeability to the medium may for example be ethylene vinyl acetate (EVA).
A suitable material having poor permeability to the medium is polyvinyl chloride (PVC).
The object of indicating a method of determining the concentration curve of a medium along a path with the aid of a flexible sensor tube is achieved according to the invention in that a conveying medium is fed into the beginning of said flexible sensor tube at intervals of time and in that at the end of the flexible sensor tube the conveying medium arriving is monitored for the admixture of the medium which is to be detected. Through the use of one of the variants of said flexible sensor tube, reliable determination of the concentration curve is possible.
With the flexible sensor tube according to the invention the advantage is in particular gained that the flexible sensor tube can be produced quickly with simple means. The first and second variants consist of a homogeneous, internally coated flexible tube which is simple to produce. The third variant, which in the longitll~;n~l direction has an insert of a different material, is also ea~y to produce. For this purpose only one band has to be bent into the shape of a trough or a C-shape, whereupon the remaining gap is closed with the other material.
Exemplary embodiments of the flexible sensor tube according to the invention and also of the method of determining the concentration curve of a medium along a path will be explained in greater detail with reference to the drawings:
Figure 1 shows a flexible sensor tube in conjunction with a pump and a sensor for determining the concentration curve of a medium along a path.
Figure 2 shows a flexible sensor tube which is completely coated internally with a material having poor permeability.
Figure 3 shows a flexible sensor tube which, except for a strip extending in the longitudinal direction, is coated internally with a material which is impermeable or has poor permeability.
~151 ~62 _ - 8 -Figure 4 shows a flexible sensor tube which, except for a strip ext~n~;ng in the longitudinal direction of the flexible sensor tube and consisting of a material having good permeability, consists of a material which is impermeable or has poor permeability.
Figure 5 shows a variant of the e_bodiment according to Figure 3.
Figure 6 shows a variant of the ~mhodiment according to Figure 4, namely with a polygonal cross-section and arranged in a double seal.
With a flexible sensor tube 3, 13 according toFigures 2 to 6 the concentration curve of a medium, for example a hydrocarbon, along this flexible sensor tube 3, 13 can be determined by a leakage detection and location method known as such. To this end, as shown in Figure 1, at the beginning of the flexible sensor tube 3 there is arranged a pump 4, from which volumes of air are delivered at intervals through the flexible sensor tube 3. The pump 4 is in each case switched on for a relatively short conveying period and then switched off for a relatively long diffusion period. The medium can penetrate from outside into the flexible senCor tube 3.
During the diffusion period a concentration curve with a local concentration m-Y;mllm of the medium can build up in the flexible sensor tube 3. In the next conveying period the concentration m~;mllm is fed to and detected by a suitable sensor 5 arranged at the end of the flexible sensor tube 3. If the penetrated medium is detected by the sensor 5 in a particular air volume, the position in the flexible sensor tube 3 where the medium ha~
penetrated in the latter can be determined, with the aid of the known speed of flow of the air volume in the flexible sensor tube 3, from the time elapsing between the commencement of the conveying period g and the moment at which the concentration ~-Y;m~lm of the medium arrived at the sensor 5. Any of the flexible sensor tubes 3a - 3d or 13 shown in Figures 2 to 6 can for example take the place of the flexible sensor tube 3 in Figure 1.
The flexible sensor tube 3a shown in Figure 2 consists of a flexible tube 1 of a material which has good permeability to the medium the concentration curve of which along the flexible sensor tube 3a is to be determined. The flexible tube 1 is provided internally with a thin coating 2 consisting of a material having poor permeability to the medium. The thickness of the thin coating 2 may be between 100 ~m and 800 ~m. The material having good permeability may be ethylene vinyl acetate (EVA) and the material having poor permeability may be polyvinyl chloride (PVC). A medium encountering from the outside the flexible sensor tube according to Figure 2 quickly penetrates into the permeable flexible tube 1 and then also passes through the relatively thin coating 2. From the interior of the flexible sensor tube 3a, however, the medium is practically not absorbed by the walls of the flexible tube, since it there first encounters the thin coating 2 of material having poor permeability and in addition is moved in the interior of the flexible sensor tube 3a. Because of the thin coating 2, medium which has penetrated is trapped in the flexible sensor tube 3a as it is conveyed. No noteworthy part of the medium passes out of the flexible sensor tube 3a, nor is any noteworthy part of the medium absorbed in the wall of the flexible tube. This is due to the fact that the thin coating 2 has low permeability to the medium and in addition scarcely absorbs vapor molecules which could originate from the medium.
21~1962 The flexible sensor tube 3a according to Figure 2 can be produced with simple means. For the application of the thin coating 2 to the inside wall of the flexible tube 1 a process of precipitation from a gas phase, a lacquering process or an immersion process are for example suitable. It is also possible to insert an inner flexible tube of sheet material, which is then pressed by pressure from inside against the inner surface of the flexible tube 1.
10According to Figure 3, in another ~hoAim~nt of the flexible sensor tube 3a, a flexible tube 6 is provided which consists of a material having good - permeability to the medium. The flexible tube 6 i8 provided on the inside with a coating 7 of material which - 15 is impermeable or has poor permeability, while a strip 6a of the inside surface of the flexible tube 6 is left free. The strip 6a extends in this case in the Ilgitll~i n~l direction over the entire length of the flexible tube 6. The coating 7 can have a thickness such that it ensures the mechanical stability of the flexible sensor tube 3b according to Figure 3. A medium reaching the flexible sensor tube 3b according to Figure 3 from outside easily penetrates into the flexible tube 6 and, inside the material of the flexible tube 6, reaches the uncoated strip 6a. The medium there passes into the interior of the flexible sensor tube 3b. It is impossible for any noteworthy amount of the trapped medium to pass out of the flexible sensor tube 3b again through the wall of the latter, because the relatively thick coating 7 neither allows the passage of the medium nor absorbs it.
The probability that noteworthy parts of the medium will reach the uncoated strip 6a, which is only narrow, from the inside is very slight. The coating 7 can have a thickness between 1 mm and 5 mm. The coating 7 consequently assists or ensures the mechanical stability of the flexible sensor tube 3b. The width b of the uncoated strip 6a amounts for example to between 0.1 mm and 2 mm. It is thereby ensured that from the interior of the flexible sensor tube 3b very little material - ` 2151962 can pass out. The coating 7 can be applied to the flexible tube 6 in the same way as the coating 2 is applied to the flexible tube 1 in Figure 2. The relatively great thickness of the coating 7, however, also makes it possible for the coating 7 first to be produced as a body and for the flexible tube 6 then to be fitted onto this body comprising the coating 7. This can for example be done by extrusion.
According to Figure 4 another variant of the flexible sensor tube 3c is composed of a band 8 which is bent into the shape of a trough or channel or a C-shape and which consists of a material impermeable or having poor permeability to the medium. The slot-like aperture extending in the longitll~inAl direction of the bent band 8 is closed by a strip 8a which has the width b and which consists of a material having good permeability to the medium. In this embodiment the medium passes from outside through the strip 8a into the interior of the flexible sensor tube 3c. Since as a rule a very large amount of the medium will be present outside the flexible sensor tube 3c and an adequate diffusion period is provided, an amount sufficient for the determination of the concentration curve passes into the interior of the flexible sensor tube 3c.
The medium there encounters almost exclusively the impermeable material of the bent band 8, 80 that it cannot pass out of the flexible sensor tube 3c within a compara-tively short conveying period. A suitable width b of the slot-like aperture is between 0.1 mm and 2 mm, as in the case of the strip 6a according to Figure 3. In order to ensure adequate mechanical stability the bent band 8 has for example a thickness between 1 mm and 5 mm.
The flexible sensor tube 3d according to Figure 5 largely corresponds to the flexible sensor tube 3c according to Figure 4. The flexible sensor tube 3d according to Figure 5 is also formed from a band 9, bent into the shape of a trough, of material which is impermeable or has poor permeability.
21~i1962 The aperture left, which has the width b, is closed by a strip 10 of permeable material. In order to simplify production, the strip 10 is not fitted into the aperture as in the case of the strip 8a in Figure 4; on the contrary, it covers the aperture. As in the embodiment according to Figure 4, the band 9 can have a thickness between 1 mm and 5 mm. The slot-like aperture first r~m~; n; ng can for example have a width b between 0.1 mm and 2 mm after the band 9 has been bent into the shape of a trough.
As illustrated in Figures 2 to 5, the flexible sensor tube 3 can have a circular cross-section.
However, in accordance with Figure 6 it may also have a polygonal, particularly a rectangular or square cross-section. In this case the flexible sensor tube 13 may have top and bottom surfaces which are parallel to one another and which, in the case of utilization inside a double seal, can lie against the two seals 11, 12 of this double seal, which may be sheets. A flexible sensor tube 13 of this kind here serves as a support in the double seal. The double seal together with the flexible sensor tube 13 can in this case be a component part of a device for sealing and monitoring a garbage dump in accordance with DE-OS 41 09 520.
The polygonal flexible sensor tube 13 illustrated in Figure 6 consists of a band 14, bent into the shape of a trough, of material which is impermeable or has poor permeability. The aperture left i8 closed by a strip 15 of permeable material which has the width b.
The flexible sensor tube 13 thus largely corre-sponds to the flexible sensor tube 3c according to Figure 4. However, the variants of the flexible sensor tube 3 in accordance with Figures 2, 3 or 5 may also be given a polygonal shape, as illustrated in Figure 6.
The flexible sensor tubes 3, 13 of Figures 2 to 6 are particularly suitable for determining the concen-tration curve of a medium along a path by means of an apparatus according to Figure 1, since, although they receive the medium, they nevertheless ab~orb or allow the e~cape of the trapped medium only to a slight extent. In particular, the flexible sensor tubes 3, 13 according to Figures 2 to 6 can be produced quickly and reliably with simple means.
~:E3ff TRANSL~UON
Flexible sensor tube The invention relates to a flexible sensor tube for determ;n;ng the concentration curve of a medium along a path. The invention also relates to a method of determ; n; ng the concentration curve of a medium along a path with the aid of a flexible sensor tube of this kind.
A flexible sensor tube of this kind can be used for monitoring pipes, tanks or garbage dumps.
A flexible sensor tube and an apparatus for operating it are known from DE-PS 24 31 907. With its aid it can be ascertained whether a medium is present in the vicinity of the flexible sensor tube. In addition, it is possible to determine the point on the flexible sensor tube where the medium encounters the flexible sensor tube. A concentration curve over the length of the flexible sensor tube can be produced. The flexible tube is permeable to the medium to be detected. A pump is arranged at one end of the flexible tube. With the aid of this pump, individual volumes of a conveying medium can be conveyed through the flexible tube one after the other at intervals of time. A suitable conveying medium is a gas, particularly air. In this way the flow passes through the flexible tube at regular intervals of time, that is to say with a constant frequency, for a conveying period in each case. A sensor sensitive to the medium to be detected is provided at the other end of the flexible tube. Between each two conveying periods the pump remains switched off for a diffusion period, which is distinctly longer than a conveying period. If a medium which is to be detected comes into the vicinity of the flexible tube, it penetrates into the latter within a diffusion period of this kind and is brought to the sensor within a conveying period by the next volume of conveying medium.
Since the conveying medium flows at a known speed, the point where the medium has passed into the flexible tube between two pumping operations can be accurately deter-mined from the difference between the time when the pump is switched on and that when the sensor responds. In addition, the amount of medium that has penetrated can be determined.
From EP-0 175 219 B1 a pipe is known which can be used as a flexible sensor tube in the manner described.
This pipe contains a tubular pipe which is impermeable to the medium to be detected and which has individual apertures. This pipe of impermeable material can be surrounded by a pipe of a permeable material. It is also possible for only the apertures in this pipe of impermeable material to be closed by a permeable material. During its conveyance through the pipe the medium which has diffused into the latter from outside can diffuse out of the pipe again only to a very limited extent while it is being conveyed through the pipe, since the inner wall of the pipe is for the most part impermeable. The production of a hollow pipe of this kind is very expensive, since the impermeable pipe has to be provided with a number of apertures, particularly bores.
The object on which the invention is based is that of providing a flexible sensor tube which works reliably in the determination of the concentration curve of a medium along a path and in addition can be produced quickly and in a simple manner. The intention is also to specify a method of determining the concentration curve of a medium along a path with the aid of a flexible sensor tube of this kind.
The first object is achieved in a first embodi-ment of the invention in that a flexible tube of a material having good permeability to the medium is completely 2151~2 _ - 3 -provided on the inside with a thin coating of a material having poor permeability to the medium.
The advantage is thereby achieved that the medium reaching the flexible sensor tube from the outside always encounters a material which has good permeability and can therefore easily penetrate into said material. From that point an amount of medium sufficient for detection overcomes the thin coating of material having poor permeability and passes into the interior of the flexible sensor tube. From there the medium is practically unable to pass out of the flexible sensor tube through the wall of the latter. This is due to the fact that said thin coating of the material having poor permeability to the medium bounds the interior space of the flexible sensor tube. Because of the relatively fast conveyance of the medium in the flexible sensor tube, the medium has no time to penetrate again into the thin coating to any noteworthy extent. Consequently, it cannot pass to the outside from the flexible tube to any noteworthy extent.
It is thereby ensured that the measurements made are not falsified.
The material having poor permeability absorbs vapor molecules only to a very slight extent. In addition, it has low affinity for nonpolar molecules, which for example include hydrocarbons. It is precisely such substances that frequently have to be detected.
The advantage is therefore achieved that on its path from the outside into the flexible sensor tube the medium can overcome the thin coating within the diff-usion period, whereas from the interior of the flexiblesensor tube it can scarcely penetrate into the coating within the conveying period, 80 that it remains trapped in the flexible sensor tube. Owing to the fact that practically no medium which has penetrated into the flexible sensor tube is lost during its conveyance, the concentration curve can be determined very accurately.
2151S5~
-_ - 4 -With the flexible sensor tube in question the advantage is in particular achieved that said tube can be produced quickly with simple means, since no apertures have to be formed in it.
5The coating of the flexible sensor tube can be effected by processes of precipitation from a gas phase, lacquering processes or immersion processes. It is also possible to insert an inner flexible tube, which is subsequently pressed against the inner surface by expansion of said inner tube.
The thickness of the coating of material having poor permeability amounts for example to between 100 ~m - and 800 ~m. Such a thin coating is not a significant obstacle for a large amount of the medium which has penetrated into the relatively thick wall of the flex-ible sensor tube of material having good permeability.
Nevertheless, it prevents the penetration of the medium from the inside into the wall of the flexible sensor tube.
20In a second embodiment the object is achieved in accordance with the invention in that a flexible tube of a material having good permeability to the medium is coated on the inside with a material which is impermeable or has poor permeability to the medium, while a narrow strip exten~;ng in the longitudinal direction of the flexible tube is left free.
The advantage is thereby gained that at the uncoated strip a particularly large amount of medium can pass from the outside into the flexible sensor tube. This is assisted by the fact that in the material having good permeability the medium can pass to the strip having particularly good permeability, even if it should have penetrated at a different point. The medium which has arrived in the flexible sensor tube can however scarcely leave the latter, because the strip having good permeability is very small in comparison with the entire inner surface of the flexible sensor tube. Still less medium can _ - 5 -leave the flexible sensor tube again if, in6tead of being of material having poor permeability, the coating consists of impermeable material. Only the free strip is then available.
The strip has for example a width of 0.1 mm to 2 mm. With such a narrow strip the advantage is gained that almost no medium can leave the flexible tube again.
Leaving the strip free, the flexible tube is for example coated with a coating of a thickness between 1 mm and 5 mm. This coating contributes toward the mechanical stability of the flexible sensor tube.
The flexible tubes of the first and second embodiments can for example have a circular or polygonal, for example rectangular, cross-section.
In a third emboA; -nt the object is achieved in accordance with the invention in that a band, which consists of a material impermeable or having poor permeability to the medium is bent into the shape of a trough, leaving free a slot-like aperture, and in that the slot-like aperture is closed by a strip, extending in the longit~;n~l direction of the band, of a material having good permeability to the medium.
In this embodiment also the penetrated medium is to a large extent trapped in the flexible sensor tube.
The slot-like aperture has for example a width between 0.1 mm and 2 mm. The band may for example be 1 mm to 5 mm in thickness. The mechanical stability of the flexible sensor tube is thereby ensured.
The band bent into the shape of a trough or channel may for example have a circular or polygonal cross-section.
All flexible sensor tubes according to the invention are in particular distinguished in that they can be produced quickly in a simple manner. Complete coating and also coating with a strip left free can easily be achieved. A flexible sensor tube having a strip consisting of a different material than the remainder of the tube is also easy to produce.
If the flexible sensor tube has a polygonal cross-section having two faces parallel to one another, it can be inserted particularly well into a space which is to be monitored and which is bounded by two parallel seals, for example sheets. The parallel faces of the flexible sensor tube can in that case lie against the seals, so that the flexible sensor tube serves as a spacer between the seals.
Seals of this kind may be component parts of a device, known from DE-OS 41 09 520, for sealing and monitoring a volume, which may be a garbage dump.
The material having good permeability to the medium may for example be ethylene vinyl acetate (EVA).
A suitable material having poor permeability to the medium is polyvinyl chloride (PVC).
The object of indicating a method of determining the concentration curve of a medium along a path with the aid of a flexible sensor tube is achieved according to the invention in that a conveying medium is fed into the beginning of said flexible sensor tube at intervals of time and in that at the end of the flexible sensor tube the conveying medium arriving is monitored for the admixture of the medium which is to be detected. Through the use of one of the variants of said flexible sensor tube, reliable determination of the concentration curve is possible.
With the flexible sensor tube according to the invention the advantage is in particular gained that the flexible sensor tube can be produced quickly with simple means. The first and second variants consist of a homogeneous, internally coated flexible tube which is simple to produce. The third variant, which in the longitll~;n~l direction has an insert of a different material, is also ea~y to produce. For this purpose only one band has to be bent into the shape of a trough or a C-shape, whereupon the remaining gap is closed with the other material.
Exemplary embodiments of the flexible sensor tube according to the invention and also of the method of determining the concentration curve of a medium along a path will be explained in greater detail with reference to the drawings:
Figure 1 shows a flexible sensor tube in conjunction with a pump and a sensor for determining the concentration curve of a medium along a path.
Figure 2 shows a flexible sensor tube which is completely coated internally with a material having poor permeability.
Figure 3 shows a flexible sensor tube which, except for a strip extending in the longitudinal direction, is coated internally with a material which is impermeable or has poor permeability.
~151 ~62 _ - 8 -Figure 4 shows a flexible sensor tube which, except for a strip ext~n~;ng in the longitudinal direction of the flexible sensor tube and consisting of a material having good permeability, consists of a material which is impermeable or has poor permeability.
Figure 5 shows a variant of the e_bodiment according to Figure 3.
Figure 6 shows a variant of the ~mhodiment according to Figure 4, namely with a polygonal cross-section and arranged in a double seal.
With a flexible sensor tube 3, 13 according toFigures 2 to 6 the concentration curve of a medium, for example a hydrocarbon, along this flexible sensor tube 3, 13 can be determined by a leakage detection and location method known as such. To this end, as shown in Figure 1, at the beginning of the flexible sensor tube 3 there is arranged a pump 4, from which volumes of air are delivered at intervals through the flexible sensor tube 3. The pump 4 is in each case switched on for a relatively short conveying period and then switched off for a relatively long diffusion period. The medium can penetrate from outside into the flexible senCor tube 3.
During the diffusion period a concentration curve with a local concentration m-Y;mllm of the medium can build up in the flexible sensor tube 3. In the next conveying period the concentration m~;mllm is fed to and detected by a suitable sensor 5 arranged at the end of the flexible sensor tube 3. If the penetrated medium is detected by the sensor 5 in a particular air volume, the position in the flexible sensor tube 3 where the medium ha~
penetrated in the latter can be determined, with the aid of the known speed of flow of the air volume in the flexible sensor tube 3, from the time elapsing between the commencement of the conveying period g and the moment at which the concentration ~-Y;m~lm of the medium arrived at the sensor 5. Any of the flexible sensor tubes 3a - 3d or 13 shown in Figures 2 to 6 can for example take the place of the flexible sensor tube 3 in Figure 1.
The flexible sensor tube 3a shown in Figure 2 consists of a flexible tube 1 of a material which has good permeability to the medium the concentration curve of which along the flexible sensor tube 3a is to be determined. The flexible tube 1 is provided internally with a thin coating 2 consisting of a material having poor permeability to the medium. The thickness of the thin coating 2 may be between 100 ~m and 800 ~m. The material having good permeability may be ethylene vinyl acetate (EVA) and the material having poor permeability may be polyvinyl chloride (PVC). A medium encountering from the outside the flexible sensor tube according to Figure 2 quickly penetrates into the permeable flexible tube 1 and then also passes through the relatively thin coating 2. From the interior of the flexible sensor tube 3a, however, the medium is practically not absorbed by the walls of the flexible tube, since it there first encounters the thin coating 2 of material having poor permeability and in addition is moved in the interior of the flexible sensor tube 3a. Because of the thin coating 2, medium which has penetrated is trapped in the flexible sensor tube 3a as it is conveyed. No noteworthy part of the medium passes out of the flexible sensor tube 3a, nor is any noteworthy part of the medium absorbed in the wall of the flexible tube. This is due to the fact that the thin coating 2 has low permeability to the medium and in addition scarcely absorbs vapor molecules which could originate from the medium.
21~1962 The flexible sensor tube 3a according to Figure 2 can be produced with simple means. For the application of the thin coating 2 to the inside wall of the flexible tube 1 a process of precipitation from a gas phase, a lacquering process or an immersion process are for example suitable. It is also possible to insert an inner flexible tube of sheet material, which is then pressed by pressure from inside against the inner surface of the flexible tube 1.
10According to Figure 3, in another ~hoAim~nt of the flexible sensor tube 3a, a flexible tube 6 is provided which consists of a material having good - permeability to the medium. The flexible tube 6 i8 provided on the inside with a coating 7 of material which - 15 is impermeable or has poor permeability, while a strip 6a of the inside surface of the flexible tube 6 is left free. The strip 6a extends in this case in the Ilgitll~i n~l direction over the entire length of the flexible tube 6. The coating 7 can have a thickness such that it ensures the mechanical stability of the flexible sensor tube 3b according to Figure 3. A medium reaching the flexible sensor tube 3b according to Figure 3 from outside easily penetrates into the flexible tube 6 and, inside the material of the flexible tube 6, reaches the uncoated strip 6a. The medium there passes into the interior of the flexible sensor tube 3b. It is impossible for any noteworthy amount of the trapped medium to pass out of the flexible sensor tube 3b again through the wall of the latter, because the relatively thick coating 7 neither allows the passage of the medium nor absorbs it.
The probability that noteworthy parts of the medium will reach the uncoated strip 6a, which is only narrow, from the inside is very slight. The coating 7 can have a thickness between 1 mm and 5 mm. The coating 7 consequently assists or ensures the mechanical stability of the flexible sensor tube 3b. The width b of the uncoated strip 6a amounts for example to between 0.1 mm and 2 mm. It is thereby ensured that from the interior of the flexible sensor tube 3b very little material - ` 2151962 can pass out. The coating 7 can be applied to the flexible tube 6 in the same way as the coating 2 is applied to the flexible tube 1 in Figure 2. The relatively great thickness of the coating 7, however, also makes it possible for the coating 7 first to be produced as a body and for the flexible tube 6 then to be fitted onto this body comprising the coating 7. This can for example be done by extrusion.
According to Figure 4 another variant of the flexible sensor tube 3c is composed of a band 8 which is bent into the shape of a trough or channel or a C-shape and which consists of a material impermeable or having poor permeability to the medium. The slot-like aperture extending in the longitll~inAl direction of the bent band 8 is closed by a strip 8a which has the width b and which consists of a material having good permeability to the medium. In this embodiment the medium passes from outside through the strip 8a into the interior of the flexible sensor tube 3c. Since as a rule a very large amount of the medium will be present outside the flexible sensor tube 3c and an adequate diffusion period is provided, an amount sufficient for the determination of the concentration curve passes into the interior of the flexible sensor tube 3c.
The medium there encounters almost exclusively the impermeable material of the bent band 8, 80 that it cannot pass out of the flexible sensor tube 3c within a compara-tively short conveying period. A suitable width b of the slot-like aperture is between 0.1 mm and 2 mm, as in the case of the strip 6a according to Figure 3. In order to ensure adequate mechanical stability the bent band 8 has for example a thickness between 1 mm and 5 mm.
The flexible sensor tube 3d according to Figure 5 largely corresponds to the flexible sensor tube 3c according to Figure 4. The flexible sensor tube 3d according to Figure 5 is also formed from a band 9, bent into the shape of a trough, of material which is impermeable or has poor permeability.
21~i1962 The aperture left, which has the width b, is closed by a strip 10 of permeable material. In order to simplify production, the strip 10 is not fitted into the aperture as in the case of the strip 8a in Figure 4; on the contrary, it covers the aperture. As in the embodiment according to Figure 4, the band 9 can have a thickness between 1 mm and 5 mm. The slot-like aperture first r~m~; n; ng can for example have a width b between 0.1 mm and 2 mm after the band 9 has been bent into the shape of a trough.
As illustrated in Figures 2 to 5, the flexible sensor tube 3 can have a circular cross-section.
However, in accordance with Figure 6 it may also have a polygonal, particularly a rectangular or square cross-section. In this case the flexible sensor tube 13 may have top and bottom surfaces which are parallel to one another and which, in the case of utilization inside a double seal, can lie against the two seals 11, 12 of this double seal, which may be sheets. A flexible sensor tube 13 of this kind here serves as a support in the double seal. The double seal together with the flexible sensor tube 13 can in this case be a component part of a device for sealing and monitoring a garbage dump in accordance with DE-OS 41 09 520.
The polygonal flexible sensor tube 13 illustrated in Figure 6 consists of a band 14, bent into the shape of a trough, of material which is impermeable or has poor permeability. The aperture left i8 closed by a strip 15 of permeable material which has the width b.
The flexible sensor tube 13 thus largely corre-sponds to the flexible sensor tube 3c according to Figure 4. However, the variants of the flexible sensor tube 3 in accordance with Figures 2, 3 or 5 may also be given a polygonal shape, as illustrated in Figure 6.
The flexible sensor tubes 3, 13 of Figures 2 to 6 are particularly suitable for determining the concen-tration curve of a medium along a path by means of an apparatus according to Figure 1, since, although they receive the medium, they nevertheless ab~orb or allow the e~cape of the trapped medium only to a slight extent. In particular, the flexible sensor tubes 3, 13 according to Figures 2 to 6 can be produced quickly and reliably with simple means.
Claims (11)
1. A flexible sensor tube (3a) for determining the concentration curve of a medium along a path, characterized in that a flexible tube (1) of a material having good permeability to the medium is completely provided on the inside with a thin coating (2) of a material having poor permeability to the medium.
2. The flexible sensor tube (3a) as claimed in claim 1, characterized in that the thickness of the thin coating (2) amounts to between 100 µm and 800 µm.
3. A flexible sensor tube (3b) for determining the concentration curve of a medium along a path, characterized in that a flexible tube (6) of a material having good permeability to the medium is coated on the inside with a material which is impermeable or has poor permeability to the medium, while a narrow strip (6a) extending in the longitudinal direction of the flexible tube (6) is left free.
4. The flexible sensor tube (3b) as claimed in claim 3, characterized in that the strip (6a) has a width between 0.1 mm and 2 mm.
5. The flexible sensor tube as claimed in one of claims 3 or 4, characterized in that the flexible tube (6) is provided with a coating (7) the thickness of which amounts to between 1 mm and 5 mm, the strip (6a) being left free.
6. A flexible sensor tube (3c, 3d, 13) for determ-ining the concentration curve of a medium along a path, characterized in that a band (8, 9, 14), which consists of a material which is impermeable or has poor perme-ability to the medium, is bent into the shape of a trough, while a slot-like aperture is left free, and in that the slot-like aperture is closed by a strip (8a, 10, 15) which extends in the longitudinal direction of the band (8, 9, 14) and consists of a material having good permeability to the medium.
7. The flexible sensor tube (3c, 3d, 13) as claimed in claim 6, characterized in that the slot-like aperture has a width between 0.1 mm and 2 mm.
8. The flexible sensor tube (3c, 3d, 13) as claimed in one of claims 6 or 7, characterized in that the band (8, 9, 14) has a thickness between 1 mm and 5 mm.
9. The flexible sensor tube (3c, 3d, 13) as claimed in one of claims 1 or 8, characterized in that the material having good permeability to the medium is ethylene vinyl acetate (EVA).
10. The flexible sensor tube as claimed in one of claims 1 to 9, characterized in that the material which is impermeable or has poor permeability to the medium is polyvinyl chloride (PVC).
11. A method of determining the concentration curve of a medium along a path with the aid of a flexible sensor tube (3, 13) according to one of claims 1 to 10, wherein a conveying medium is fed into the beginning of the flexible sensor tube (3, 13) at intervals of time and at the end of the flexible sensor tube (3, 13) the conveying medium arriving is monitored for the admixture of the medium which is to be detected.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4242806A DE4242806A1 (en) | 1992-12-17 | 1992-12-17 | Sensor hose |
| DEP4242806.8 | 1992-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2151962A1 true CA2151962A1 (en) | 1994-06-23 |
Family
ID=6475657
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002151962A Abandoned CA2151962A1 (en) | 1992-12-17 | 1993-12-09 | Flexible sensor tube |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5589647A (en) |
| EP (1) | EP0676043A1 (en) |
| JP (1) | JPH08504506A (en) |
| CA (1) | CA2151962A1 (en) |
| DE (1) | DE4242806A1 (en) |
| RU (1) | RU95114520A (en) |
| WO (1) | WO1994014043A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4424909A1 (en) * | 1994-07-14 | 1996-01-18 | Siemens Ag | Method and device for locating pollutant accumulations |
| US6129680A (en) * | 1995-06-19 | 2000-10-10 | Btg International Limited | Animal exhalation monitoring |
| US5804743A (en) * | 1996-08-20 | 1998-09-08 | General Electric Company | Downhole passive water sampler and method of sampling |
| US5939160A (en) * | 1997-02-25 | 1999-08-17 | Sealand Technology, Inc. | Low odor permeable hose |
| DE102005007988A1 (en) * | 2005-02-22 | 2006-08-24 | Framatome Anp Gmbh | Collection pipe for leakages, e.g. of hydrocarbon compounds, has a perforated carrier pipe with an electrically conductive layer and an outer covering layer |
| DE102008014808B4 (en) | 2008-03-18 | 2012-01-26 | Areva Np Gmbh | Sensor line for leakage monitoring and leak detection and method for their production |
| DE102013221799B3 (en) | 2013-10-28 | 2015-02-05 | Areva Gmbh | Hose or pipe for transporting a gas sample |
| GB2587985B (en) | 2018-05-01 | 2023-03-15 | Baker Hughes Holdings Llc | Gas sensor system |
| EP3608648A1 (en) * | 2018-08-10 | 2020-02-12 | Johann Trummer | Device and method for detecting a leak |
Family Cites Families (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE8427529U1 (en) * | 1985-01-17 | Issel, Wolfgang, Dipl.-Phys. Dr.-Ing., 7500 Karlsruhe | Hollow conduit for use in determining the concentration profiles of liquid or gaseous substances | |
| DE8427528U1 (en) * | 1985-01-17 | Issel, Wolfgang, Dipl.-Phys. Dr.-Ing., 7500 Karlsruhe | Hollow conduit for use in determining the concentration profiles of liquid or gaseous substances | |
| DE2431907C3 (en) * | 1974-07-03 | 1978-03-09 | Wolfgang Dipl.-Phys. Dr.- Ing. 7500 Karlsruhe Issel | Method and device for determining concentration profiles of liquid or gaseous substances along a route |
| DE2512995C3 (en) * | 1975-03-24 | 1979-11-29 | Hoechst Ag, 6000 Frankfurt | Film tube, in particular packaging sleeve |
| FR2410501A1 (en) * | 1976-11-15 | 1979-06-29 | Monsanto Co | MULTI-COMPONENT MEMBRANES FOR GAS SEPARATIONS |
| US4230463A (en) * | 1977-09-13 | 1980-10-28 | Monsanto Company | Multicomponent membranes for gas separations |
| US4208902A (en) * | 1978-12-20 | 1980-06-24 | Air Products And Chemicals, Inc. | Gas concentration analysis method and system |
| DE3305005C2 (en) * | 1983-02-14 | 1985-02-14 | Wolfgang Dipl.-Phys. Dr.-Ing. 7500 Karlsruhe Issel | Method and device for determining the temperature distribution along a route |
| DE3434322C2 (en) * | 1984-09-19 | 1986-08-14 | Wolfgang Dipl.-Phys. Dr.-Ing. 7500 Karlsruhe Issel | Hollow conduit for use in determining the concentration profiles of liquid or gaseous substances |
| DE3434323C2 (en) * | 1984-09-19 | 1986-11-13 | Wolfgang Dipl.-Phys. Dr.-Ing. 7500 Karlsruhe Issel | Hollow conduit for use in determining the concentration profiles of liquid or gaseous substances |
| DE3562661D1 (en) * | 1984-09-19 | 1988-06-16 | Issel Wolfgang | Hollow line for determining the concentration profiles of liquid or gaseous substances |
| IL76275A (en) * | 1985-09-02 | 1989-02-28 | Yeda Res & Dev | Water sampling system |
| US4721517A (en) * | 1987-03-06 | 1988-01-26 | Irsst - Institut De Recherche En Sante Et En Securite Du Travail Du Quebec | Sampling device for collecting fume |
| DE3712809A1 (en) * | 1987-04-15 | 1988-11-03 | Linde Ag | Process for producing hollow profiles from plastic |
| US4972704A (en) * | 1989-03-14 | 1990-11-27 | Shell Oil Company | Method for troubleshooting gas-lift wells |
| US5010776A (en) * | 1989-05-04 | 1991-04-30 | Iit Research Institute | Environmental contamination detection and analyzing system and method |
| US5259856A (en) * | 1989-09-06 | 1993-11-09 | Sumitomo Electric Industrial, Ltd. | Method of producing glass preform in furnace for heating glass |
| US5215409A (en) * | 1991-03-22 | 1993-06-01 | Siemens Aktiengesellschaft | Device for sealing off and monitoring a volume |
| DE4109520A1 (en) * | 1991-03-22 | 1992-09-24 | Siemens Ag | Device for sealing and monitoring space e.g. waste material dump - in which space is enclosed by two sealing layers between which are distance pieces and passages through which fluid medium is circulated |
| DE9107693U1 (en) * | 1991-03-22 | 1991-08-22 | Siemens Ag, 8000 Muenchen, De | |
| DE4134380A1 (en) * | 1991-10-17 | 1993-04-22 | Siemens Ag | Gas and liquid leak monitoring appts., esp. in doubly sealed refuse deposit - has sensor tube in monitoring chamber carrying pumped transport inert gas and connected to sensor of monitored medium |
| US5177996A (en) * | 1991-11-21 | 1993-01-12 | W. L. Gore & Associates, Inc. | Liquid leak detection cable |
-
1992
- 1992-12-17 DE DE4242806A patent/DE4242806A1/en not_active Withdrawn
-
1993
- 1993-12-09 CA CA002151962A patent/CA2151962A1/en not_active Abandoned
- 1993-12-09 JP JP6513660A patent/JPH08504506A/en active Pending
- 1993-12-09 RU RU95114520/28A patent/RU95114520A/en unknown
- 1993-12-09 WO PCT/DE1993/001176 patent/WO1994014043A1/en not_active Application Discontinuation
- 1993-12-09 EP EP94901741A patent/EP0676043A1/en not_active Withdrawn
-
1995
- 1995-06-19 US US08/491,395 patent/US5589647A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| WO1994014043A1 (en) | 1994-06-23 |
| US5589647A (en) | 1996-12-31 |
| EP0676043A1 (en) | 1995-10-11 |
| JPH08504506A (en) | 1996-05-14 |
| RU95114520A (en) | 1997-04-20 |
| DE4242806A1 (en) | 1994-06-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |