DE102011119635A1 - Pipe for delivery line for conveying bulk material, has spacer that is provided in annular space between inner pipe portion and outer pipe portion which is rested over two-point support on spacer rested on inside of inner pipe portion - Google Patents

Abstract

The pipe (1,2) comprises an inner pipe portion (3) that is surrounded by an outer pipe portion (4) with spacing. A spacer (6) is accommodated in an annular space (5) between the inner pipe portion and outer pipe portion. The outer pipe portion is rested over a two-point support on the spacer that is rested on inside of the inner pipe portion. An independent claim is included for device for monitoring leakage in delivery line.

Description

The invention relates to a pipe according to the preamble of claim 1 and a device for monitoring leakage in a delivery line according to the preamble of claim 11.

There are known delivery lines, which consist of an inner tube and an outer tube surrounding this at a distance. The annulus between the two tubes is filled with plastic to acoustically separate the inner tube from the outer tube ( DE 42 07 029 A1 ).

In another known delivery line ( DE 1 072 946 ), the annular space between the inner tube and the outer tube is filled by a filling compound, are embedded in the spacers in the form of spring bands. The spring bands serve to center the outer tube relative to the inner tube.

For delivery lines for fluids ( DE 10 2008 021 201 A1 ), the annular space between the inner tube and the outer tube is filled with an insulating material to keep low on the transport of the fluid heat loss of the fluid.

The invention has the object of providing the generic tube and the generic device in such a way that in use, the composite of the tubes conveyor line has a relatively low noise level. In this case, any leaks in the delivery line should be easily and reliably detected.

This object is achieved according to the invention in the generic pipe with the characterizing features of claim 1 and in the generic device according to the invention with the characterizing features of claim 11.

The tube according to the invention is characterized in that the outer tube rests on at least one 2-point support on the spacer, which in turn sits on the inner tube. As a result of this Punktabstützung the annulus between the inner and outer tube remains free. As a result, the structure-borne noise is transmitted from the inner tube only to a very limited extent on the outer tube, whereby the sound level during operation of the delivery line is substantially reduced. Since the spacers do not close the annulus, the volume of air contained in the annulus also contributes to the reduction of noise. The tube is easy to manufacture. Depending on the length, a corresponding number of spacers are fastened to the inner tube at a distance one behind the other. Subsequently, only the outer tube must be pushed. The spacers provide for the centering of the outer tube relative to the inner tube. In this way, the tubes that form the delivery line can be manufactured inexpensively. The double-walled tubes can be assembled in an easy-to-assemble way to the delivery line.

Advantageously, the spacer is provided with a ring body with which it sits on the inner tube. The spacer can be reliably attached to the inner tube in this way.

It is advantageous if the annular body of the spacer sits under elastic bias on the inner tube. This ensures in a simple manner that the spacer is not displaced on the inner tube during operation of the delivery line.

The point support of the outer tube on the spacer can be achieved in a very simple manner by the fact that project from the ring body at least two projections on which the outer tube rests. In a 2-point support these projections are diagonally opposite each other. With more than two projections, these are distributed uniformly over the circumference of the annular body. The projections may be formed so that they terminate at the free end in an edge, with which the projection rests against the inner wall of the outer tube. The free end of the projections can also be curved.

It is advantageous if the projections are provided so that they rest with their free ends under radial prestress on the inner wall of the outer tube.

Passages are formed between the projections of the annular body, so that the annular space is continuously provided over its length with a corresponding volume of air. This achieves optimal sound reduction.

In order to further improve the sound reduction, the spacer is preferably made of rubber or an elastic material, for example a corresponding plastic.

In a preferred embodiment, the annulus is closed at both ends. Then there is a closed air volume, which not only excellently serves to reduce noise during operation of the delivery line, but can also be used in an excellent manner for leakage monitoring of the inner tube. As long as the inner tube in the region of this closed annular space has no leak, the pressure and / or flow conditions in the annulus do not change. Has the inner tube, however, in the area of a closed loop, a leak, then this leads to a pressure change and / or a flow change, which can be detected by corresponding measuring devices or sensors. As a result, it is possible in a simple yet reliable manner to locate and repair the leak of the inner tube, which is not recognizable from the outside as a result of the double-walled design, or to replace the corresponding tube of the delivery line.

The annular space is advantageously closed by annular plugs. They are located at the ends of the annular space on the inner wall of the outer tube and on the outer wall of the inner tube so that the annulus is hermetically sealed. Such annular plugs may be made of rubber-like or elastic material, which are pressed between the inner tube and the outer tube, so that the plugs bear under elastic prestressing both on the inner tube and on the outer tube.

In an advantageous embodiment, the inner tube protrudes beyond the outer tube. The protruding part of the inner tube can then be used to couple adjacent tubes. The projection of the inner tube is only so large that corresponding coupling means, such as pipe clamps o. The like., Can be mounted to connect adjacent pipes.

So that a leak in the inner tube can be detected in the region of the closed annular space, at least one pressure sensor is advantageously accommodated in this annular space. When a leak occurs, the pressure in the annulus changes. If the medium in the inner tube, for example, promoted with negative pressure, then there is a reduction in pressure in the annulus. If the medium in the inner tube is conveyed with overpressure, the pressure in the annulus increases when a leak occurs. In both cases, the pressure change is detected by the pressure sensor. Advantageously, the signals of the pressure sensor are forwarded to a monitoring unit.

It is also possible to detect the occurrence of a leak in the inner tube in the region of the annular space with the aid of a flow meter. For this purpose, the outer tube is provided in the region of the annular space with at least one corresponding connection for such a flow meter. If the inner tube has a leak in the area of the annular space, then the flow conditions in the annular space change. The flowmeter accordingly sends a signal so that the leak can be easily located.

The device according to the invention according to claim 11 allows a very simple monitoring of the delivery line with respect to leaks. Over the length of the feed line annular spaces are arranged distributed uniformly, which are closed at both ends. With the measuring devices, each annulus is monitored, so that a leak in the inner tube can be detected and displayed in the area of these annuli.

Advantageously, the meter is a pressure sensor, which is housed in the annulus. If the inner tube has a leak in the region of the corresponding annular space, the pressure conditions in the annular space change, so that the pressure sensor delivers a corresponding signal.

The meter may also be a flow meter that detects a leakage flow in the respective annulus. If the inner tube has a leak in the region of the corresponding annular space, then there occurs a corresponding leakage flow, which is detected by the flow meter.

In an advantageous embodiment, the annular spaces can be fluidly connected to one another by lines.

The features specified in the dependent claims form the subject of the main claim on. However, this is not to be understood as a waiver to claim independent protection for the features of these dependent claims.

Further features of the invention will become apparent from the other claims, the description and the drawings.

The invention will be explained in more detail with reference to some embodiments shown in the drawings. Show it

1 in side view two tubes according to the invention, which are connected to each other and form part of a conveying line,

2 in front view, the pipes according to 1 .

3 in an enlarged view and in front view of a pipe bend according to 1 .

4 in enlarged and perspective view of a straight pipe according to 1 .

5 to 8th each in a radial section different embodiments of pipes,

9 the dependence of the sound level on the frequency of a blower for generating the flow in the delivery line,

10 a side view of a pipe clamp, with the pipes on a supporting structure, for. As a rail to be attached,

11 the pipe clamp according to 10 in front view,

12 a side view of a pipe coupling, with the adjacent pipes are connected to each other,

13 the pipe coupling according to 12 on average.

With the delivery line, a medium, in particular plastic granules, promoted using a pressure or suction flow. For example, the medium is conveyed from a storage container to a processing machine for the medium with the delivery line.

The delivery line is made of individual tubes 1 . 2 composed. In 1 is an example of a straight tube 1 and a curved pipe forming a pipe bend 2 shown. The two pipes 1 . 2 are connected in a medium-tight manner in a known manner. Each tube consists of an inner tube 3 with a distance from an outer tube 4 is surrounded. Between the inner and the outer tube 3 . 4 there is an annulus 5 in which at least one spacer ring forming a support ring 6 is housed. It is advantageous over the length of the tubes 1 . 2 several such support rings 6 spaced apart. The support rings 6 are designed so that they have the annulus 5 between the inner and outer tube 3 . 4 do not close.

At the ends of the outer tubes 4 There are annular plugs 7 with which the annulus 5 is sealed at its axial ends.

The inner tube 3 is longer than the outer tube 4 that way on the inner tube 3 deferred is that the inner tube 3 over both ends of the outer tube 4 survives ( 1 . 2 and 4 ). About these protruding ends of the inner tube 3 become adjacent pipes 1 . 2 interconnected, advantageously via a pipe coupling 24 ( 12 and 13 ). The individual pipes 1 . 2 can be made very easily. On the inner tube 3 At regular intervals, the necessary support rings 6 pushed. They are designed to be under elastic pretension on the outer jacket of the inner tube 3 to sit. Subsequently, the outer tube 4 pushed over. Once the outer tube 4 its necessary position in relation to the inner tube 3 has taken on both ends on the inner tube 3 the annular plugs 7 postponed and postponed until they reached the ends of the annulus 5 close tightly.

In this way, also the arcuate tubes can be 2 if they have a constant bending radius. For asymmetrical inner arches 3 with short and long straight leg is the two-piece outer tube 4 from the free end of the inner tube 3 deferred. There are two plugs 7 on the inner bow 3 next to each other, like this in 1 is shown by way of example.

The individual pipes 1 . 2 can thus be prefabricated in a simple manner, so that they only at the installation with the help of pipe couplings 24 must be composed. The inner tube 3 is matched in terms of its material and / or its interior wall design on the type of medium to be conveyed.

The support rings 6 as well as the annular plugs 7 sit firmly on the inner tube due to their elastic preload 3 so that additional fasteners are not required. In particular, the annular plug 7 sit under elastic deformation on the inner tube 3 and are under elastic bias on the inner wall of the outer tube 4 at.

The straight pipes 1 can have lengths to exemplify six feet. The arcuate tubes 2 can have large radii, for example greater than 300 mm. With the pipe couplings, the individual pipes can be 1 . 2 connect easily and reliably. The support rings 6 and the plugs 7 make sure the outer tube 4 coaxial with the inner tube 3 lies. The distance between the support rings 6 is for example one meter to 1.50 meters, depending on the required stability of the tubes. The annular plugs 7 at the ends of the outer tube 4 are advantageously made of rubber or elastic plastic. This allows the plugs 7 between the inner tube 3 and the outer tube 4 Press in under elastic deformation so that the annulus 5 is hermetically sealed at both ends.

5 shows a first embodiment of a support ring 6 , He has an annular body 8th , which under elastic pretension on the inner tube 3 sitting. The support ring 6 has projections on its outer jacket 9 on, which are arranged at an angular distance of 90 ° and over the axial width of the support ring 6 extend. The projections 9 are triangular in radial section. The projections 9 are so high that they are with their tip 10 under elastic deformation on the inner wall of the outer tube 4 issue. As a result of this described training is the support ring 6 with a 4-point support for the outer tube 4 Mistake. Between the adjacent projections 9 each becomes a crescent-shaped air gap 10a educated.

In the one air gap 10a a connection opens 11 for a measuring device 12 with which the pressure or the flow in the air gap 10a can be detected.

The support ring 6 according to 6 in turn has the ring body 8th , with which the support body under elastic prestress on the inner tube 3 sitting. From the ring body 8th stand the projections 9 from, in contrast to the previous embodiment, a curved support side 10 exhibit. The projections 9 have an angular distance of 90 ° and extend over the axial width of the support ring 6 , The edition pages 10 lie under elastic deformation on the inner wall of the outer tube 4 on, thus a 4-point support by the support ring 6 experiences. Between the projections 9 in turn become the crescent-shaped air gaps 10a educated.

The support ring 6 according to 7 has only two tabs 9 which are diametrically opposed to each other and in this embodiment have the same configuration as the projections according to 6 , The projections lie with their arcuate support side 10 under elastic deformation on the inner wall of the outer tube 4 at. The support ring 6 has the ring body 8th that under elastic deformation on the inner tube 3 sitting. With this support ring 6 becomes a 2-point support of the outer tube 4 reached.

In such a 2-point support, the projections 9 also according to the embodiment according to 5 be designed.

For a pipe 1 . 2 are advantageously the same support rings 6 used. But it is also possible in principle for a tube different configurations of support rings in the annulus 5 provided.

8th shows by way of example the case that in the annulus 5 same support rings 6 are housed. It is advantageous if adjacent support rings 6 so twisted against each other are installed, that, seen in the axial direction, between two projections 9 of a support ring each have a projection 9 of the adjacent support ring 6 lies. This can be an advantageous support of the outer tube 4 be reached over its length.

But it is also possible in principle, the support rings 6 the same orientation in succession in the annulus 5 to accommodate, so that the projections 9 adjacent support rings 6 are aligned with each other, viewed in the axial direction of the respective tube.

The 10 and 11 show an example of a pipe clamp 13 with which the pipes 1 . 2 on a support structure, for. B. a rail can be attached. The clamp 13 has two semicircular clamping sections 14 . 15 that the outer tube 4 embrace. The two clamping sections 14 . 15 are on the inside with at least one elastically yielding pad 16 provided with the pipe clamp 13 on the outside of the outer tube 4 rests. The edition 16 can extend over the entire width of the two clamping sections 14 . 15 extend. But it is also possible that, for example, two adjacent pads 16 are provided. The clamping sections 14 . 15 are connected at their ends in a known manner. To ensure easy installation, the clamp is 13 in a known manner with a quick-release system 17 provided, which is known and therefore not described in detail. The quick release system 17 connects the one ends of the two clamping sections 14 . 15 , The opposite ends of the two clamping sections 14 . 15 are by a clamping screw 18 connected to each other, with the two clamping sections 14 . 15 can be pulled firmly against each other. The existing elastically yielding material edition 16 ensures optimal sound reduction.

The 12 and 13 show an example of the pipe coupling 23 , with the adjacent pipes 1 . 2 can be connected to each other. The pipe coupling 24 has an elastically deformable cuff 25 on the two pipe ends in a joint area 19 ( 1 ) between adjacent pipes 1 . 2 is put on. On the inside of the cuff 25 is a soft and sealing gasket 26 attached, with which the impact area 19 is sealed. This can do this in the inner tube 3 conveyed medium does not escape to the outside.

The cuff 25 is designed in the manner of a tension band, which encloses the tube ends almost over 360 °. The two ends 27 . 28 the cuff 25 are reinforced and formed by at least one clamping screw 29 , in the embodiment by two clamping screws, connected to each other. The cross outward of the cuff 25 protruding ends 27 . 28 be with the clamping screws 29 pulled against each other, reducing the cuff 25 is pulled tightly around the pipe ends.

The connection of the pipes 1 . 2 together with the help of pipe couplings 24 is just one, but preferred way, the pipes 1 . 2 to assemble the support line. Adjacent pipes can also be connected to one another by other connecting means known per se.

The outer tube 4 surrounds the inner tube 3 over most of its length. The between the inner tube 3 and the outer tube 4 existing annulus 5 is at its two ends by the annular plugs 7 locked. That in the annulus 5 Air volume present can be detected of leakage of the inner tube 3 be used. Is the inner tube 3 tight, then it's in the annulus 5 Air volume under a predetermined pressure, with the meter 12 ( 5 ) can be detected. The annulus 5 extends over the entire length of the outer tube 4 because the support rings 6 the annulus 5 do not close. The support rings 6 lie just above their projections 9 on the inner wall of the outer tube 4 at.

Because of every annulus 5 a corresponding measuring device 12 is connected, is a clear localization of a possible leak of the inner tube 3 guaranteed.

Is the medium in the inner tube 6 promoted by means of a negative pressure prevails in the inner tube 3 a lower pressure than in the annulus 5 , Indicates the inner tube 3 a leak, then the pressure in the annulus decreases 5 from. This will be from the to the port 11 connected pressure gauge detected and displayed in a suitable manner. The pressure drop is thus an indication of a leakage of the inner tube 3 in the area of the monitored annulus 5 ,

In this way, every annulus can 5 be monitored by such a pressure gauge, so that leaks on the inner tube 3 can be recorded easily and reliably within the funding line.

Pressure monitoring in the annuli 5 can also be done by sensors which are arranged in the respective annular spaces. These sensors are coupled with a central system monitoring. The transmission of the print data can be wireless, for example via radio signals, IR signals u. The arrangement is such that each individual pressure sensor can be detected and determined by the system monitoring. In case of danger, it can be easily determined which pressure sensor has delivered the corresponding signal.

The negative pressure in the inner tube 3 sits in the event of leakage radially through the leakage point in the annulus 5 continued. This will cause a pressure change in the annulus 5 between the inner tube 3 and the outer tube 4 generated. This pressure change occurs over the entire length of the annulus 5 on, because the support rings 6 only over small areas on the inner wall of the outer tube 4 issue. The crescent-shaped air gaps 10a between the support rings 6 and the outer tube 4 form the axial connection of the air volumes in the annulus 5 , The connection 11 for the pressure gauge 12 can thus at any point along the annulus 5 on the outer tube 4 to be ordered.

A leakage of the inner tube 3 can also be detected by flow monitoring. In this case is to the connection 11 a flowmeter connected. With him is a leakage flow from the outside into the annulus 5 detected when the inner tube 3 in the area of the annulus 5 has a leakage point and the medium in the inner tube 3 is promoted by means of negative pressure.

In a pressure transfer of the medium in the inner tube 3 the leakage flow reverses. In this case it takes place from the annulus 5 out to the outside.

The air flow meter detects this leakage flow and displays it in a suitable manner. For this reason, once again, a leakage point can be detected easily and reliably in the entire delivery line so that it can be eliminated at an early stage.

Every annulus 5 is in this case provided with such an air flow meter, so that each annulus 5 can be monitored. But it is also possible to use sensors that are coupled to a central monitoring system. The air flow sensors advantageously send their signals wirelessly to the monitoring system. The data transmission can be done for example by radio signals or IR signals. The monitoring system displays the respective sensor that has detected a leak. It is thus easily possible, the occurred leakage in the inner tube 3 to eliminate.

The delivery line consists in the manner described above on the pipe couplings 24 interconnected pipes 1 . 2 , The monitored annuli 5 are located between these pipe couplings, so that the entire delivery line can be monitored over its length for the occurrence of leaks.

The double-walled pipes 1 . 2 can be inexpensively and easily assembled ready for installation. The pipes can be like conventional piping with the help of pipe couplings 24 be connected to each other. The leakage monitoring by means of the described pressure measurement or flow monitoring is simple and reliable. In case of damage, the pipes can be easily exchanged.

The double-walled structure of the pipes 1 . 2 also has the advantage that the noise emission during operation of the delivery line is substantially reduced due to the air cushion. In addition, prevent the existing rubber or elastic material support rings 6 and stopper 7 that the structure-borne noise from the inner tube 3 directly on the outer tube 4 is transmitted. The volume of air in the annular spaces 5 ensures that between the inner tube 3 and the outer tube 4 only the airborne sound is transmitted. The airborne sound propagation can be reduced advantageously by the fact that the annular spaces 5 be set under vacuum or evacuated.

There is a possibility of the individual annuli 5 fluidically connect with each other. As in 1 is shown by dashed lines by way of example, the annular spaces 5 adjacent pipe sections 1 . 2 through a pipe 20 be connected to each other. It may, for example, be a piece of hose connected to corresponding connections of the outer tubes 4 adjacent pipes 1 . 2 connected.

Even with such a design is a clear localization of the leakage point in the inner tube 3 possible. With such a design of the delivery line, air flow measuring devices are used as measuring devices. If leakage occurs, the airflow gauges located in the area between the fan and the leakage point will respond while the downstream airflow gauges downstream of the leakage point will not respond. This is due to the fact that at the leakage point in the manner described, a leakage flow from the outside into the annulus 5 and from there by the leakage position in the inner tube 3 occurs. From here, this air then flows in the direction of the blower. Thus, even in this embodiment, the leak can be clearly located.

The delivery line only generates a low level of noise during use, including the annular spaces 5 , the support rings 6 , the annular stopper 7 as well as the pipe clamps 13 contribute. The clamps 13 lie with their elastic pads 16 on the outer tube 4 on, which serve the acoustic decoupling. The clamps 13 be attached to rails in a known manner. These are the pipe clamps 13 ( 10 and 11 ) with an approach 21 provided with it in an appropriate opening 22 a strap-shaped carrier 23 engage, which is attached for example to a (not shown) rail or other holder.

Sound level measurements were carried out on the delivery line. 9 shows the dependence of the absolute sound level on the frequency of the blower, with which the flow rate in the inner tube 3 is produced. The diagram shows the conditions in the arcuate tube 2 , Basically the same results are also shown by the straight tube 1 ,

With the curve 24 the conditions are shown in a conventional delivery line. The sound level increases with increasing blower frequency. In the example measured, the absolute sound level at a frequency of 30 Hz was about 79 dB (A). At a frequency of 70 Hz, the sound level was 85 dB (A).

In the example shown, a constant sound level of 75 dB (A) was required, regardless of the fan speed ( 25 ). The curve 26 shows the course of the pipe 2 the support line. Over the measured frequency range, the sound level is always well below the required sound level curve 25 , In the example, the sound level is about 65 dB (A) at a blower frequency of 30 Hz. At a frequency of 70 Hz, the sound level is about 73 dB (A).

A comparison of the sound level curves 24 and 26 shows that with the described delivery line an average reduction of the sound level by about 13 dB (A) is achieved in a very simple manner.

Due to the described design of the delivery line, it is possible to retrofit existing delivery lines later. It only has to be the outer tube 4 with the help of the support rings 6 and the stopper 7 be deferred to the existing production pipes. For the outer tube 4 a weight-light material, preferably aluminum, can be used. The achieved by this design noise reduction is also very inexpensive.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4207029 A1 [0002]
• DE 1072946 [0003]
• DE 102008021201 A1 [0004]

Claims (15)

Pipe for a conveyor line for conveying bulk material, with an inner tube which is surrounded by a distance from an outer tube, and with at least one spacer, which is housed in an annular space between the inner tube and the outer tube and the two tubes centered against each other, characterized that the outer tube ( 4 ) via at least one 2-point support on the spacer ( 6 ) rests on the inner tube ( 3 ) sits. Pipe according to claim 1, characterized in that the spacer ( 6 ) with a ring body ( 8th ) on the inner tube ( 3 ) sits. Pipe according to claim 2, characterized in that the annular body ( 8th ) under elastic prestressing on the inner tube ( 3 ) sits. Pipe according to claim 2 or 3, characterized in that the annular body ( 8th ) at least two projections ( 9 ) protrude, on which the outer tube ( 4 ) rests. Pipe according to one of claims 1 to 4, characterized in that the spacer ( 6 ) consists of rubber or elastic material. Pipe according to one of claims 1 to 5, characterized in that the annular space ( 5 ) is closed at both ends. Pipe according to claim 6, characterized in that the annulus ( 5 ) by annular plugs ( 7 ) is closed. Tube according to one of claims 1 to 7, characterized in that the inner tube ( 3 ) over the outer tube ( 4 ) protrudes. Pipe according to one of claims 1 to 8, characterized in that in the annular space ( 5 ) At least one pressure sensor is housed. Tube according to one of claims 1 to 9, characterized in that the outer tube ( 4 ) at least one connection ( 11 ) for a measuring device ( 12 ), in particular a flow meter. Device for monitoring leakage in a delivery line, which is composed of tubes, in particular according to one of claims 1 to 10, with at least one inner tube, which is surrounded by at least one outer tube to form an annular space, characterized in that distributed along the delivery line annular spaces ( 5 ) are arranged, which are each closed at both ends and by at least one measuring device ( 12 ) be monitored. Apparatus according to claim 11, characterized in that the measuring device ( 12 ) is a pressure sensor in the annulus ( 5 ) is housed. Apparatus according to claim 11 or 12, characterized in that the measuring device ( 12 ) is a flow meter that has a leakage flow in the annulus ( 5 ) detected. Device according to one of claims 11 to 13, characterized in that the measuring devices ( 12 ) are connected to a monitoring system. Device according to one of claims 11 to 14, characterized in that the annular spaces ( 5 ) through pipes ( 20 ) are fluidly connected to each other.

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