Measuring device for determining a distribution of a heat transfer medium and method for determining a distribution of a heat transfer medium

Abstract

A measuring device for determining a distribution of a heat transfer medium on an inner wall of a shaftless container which rotates when used to heat the heat transfer medium with concentrated solar radiation in a solar thermal power plant or as a rotary kiln includes a distance measuring device for determining a thickness of a film of the heat transfer medium on the inner wall of the container. The distance measuring device includes at least one optical device for detecting at least one height profile along at least one measurement line projected onto the inner wall and at least one position transducer for determining a current rotational position of the respective measurement line on the inner wall. A method for determining a distribution of a heat transfer medium on an inner wall of a shaftless container is also provided.

Claims

1. A measuring device for determining a distribution of a heat transfer medium on an inner wall of a shaftless container which rotates when used as intended and which is designed in particular to heat the heat transfer medium with concentrated solar radiation in a solar thermal power plant or as a rotary kiln, comprising a distance measuring device for determining a thickness of a film of the heat transfer medium on the inner wall of the container, wherein the distance measuring device has at least one optical device for detecting at least one height profile along at least one measurement line projected onto the inner wall and at least one position transducer for determination of a current rotational position of the respective measurement line on the inner wall.

2. The measuring device according to claim 1, wherein the distance measuring device is designed to detect distance data directly on the inner wall of the container along the measurement line in order to create the height profile.

3. The measuring device according to claim 1, wherein the distance measuring device is designed to detect distance data directly on the film of the heat transfer medium on the inner wall of the container along the measurement line in order to create the height profile.

4. The measuring device according to claim 1, wherein the measurement line extends parallel to a longitudinal axis of the container.

5. The measuring device according to claim 1, wherein the position transducer is attached to the container and detects a rotational position of the container, in particular synchronously with the projected measurement line.

6. The measuring device according to claim 5, wherein the position transducer has a magnetic tape which is placed around the container, in particular wherein the rotational position is determined via a magnetic tape comprising a number of magnetic poles which are read out by a sensor of the position transducer.

7. The measuring device according to claim 1, wherein a computing device is coupled to the distance measuring device and/or the position transducer.

8. The measuring device according to claim 1, wherein the distance measuring device protrudes into the container on a holder.

9. A method for determining a distribution of a heat transfer medium on an inner wall of a shaftless container that rotates when used as intended, in particular in which the heat transfer medium is heated with concentrated solar radiation in a solar thermal power plant or a rotary kiln, by means of a measuring device according to claim 1, wherein the distance measuring device detects at least one height profile along at least one measurement line projected onto the inner wall by means of at least one optical device and at least one position transducer determines a current position of the respective measurement line on the inner wall.

10. The method according to claim 9, wherein a position of the two height profiles with and without a heat transfer medium on the inner wall of the container is determined in relation to a rotational position of the container.

11. The method according to claim 9, wherein the distance measurement is carried out without solar radiation entering the container.

12. The method according to claim 9, wherein a difference between distance data of the film and distance data of the inner wall is formed and from this difference a position-dependent distribution of the film of the heat transfer medium on the inner wall is determined.

13. The method according to claim 9, wherein a measuring frequency of the position transducer is adapted to a length of the measurement line in the axial direction of the container.

14. The method according to claim 9, wherein a reference measurement is carried out to determine an eccentricity and/or lack of circularity of the container and a length of the measurement lines in the direction of the longitudinal axis of the container is adapted.

15. The method according to claim 9, wherein the determination of the distribution of heat transfer medium on the inner wall is carried out repeatedly and changes in the distribution are detected, in particular wherein a maintenance requirement display is indicated if permissible tolerances of the changes are exceeded.

16. Use of a measuring device for determination of a distribution of a heat transfer medium on an inner wall of a container which rotates when used to heat the heat transfer medium with concentrated solar radiation in a solar thermal power plant or in a rotary kiln, the measuring device comprising a distance measuring device for determination of a thickness of a film of the heat transfer medium on the inner wall of the container, detecting, using at least one optical device, at least one height profile along at least one measurement line projected onto the inner wall and determining, using at least one position transducer, a current rotational position of the respective measurement line on the inner wall, wherein the position transducer has a combination of a magnetic tape and a sensor for detecting a rotational position of the shaftless rotating container.

17. Use according to claim 16, wherein the magnetic tape is arranged on the container and rotates with the container, and the sensor is arranged above the magnetic tape.

18. Use according to claim 16, wherein the sensor is arranged on the container and rotates with the container and the magnetic tape is arranged above the sensor.

19. Use of a combination of a magnetic tape and a sensor arranged above it to detect a rotational position of a shaftless rotating container in a solar thermal power plant or a rotary kiln.

20. Use according to claim 19, wherein the magnetic tape is arranged on the container and rotates with the container and the sensor is arranged above the magnetic tape.

21. The method according to claim 19, wherein the sensor is arranged on the container and rotates with the container and the magnetic tape is arranged above the sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages will be apparent from the following description of the drawings. Exemplary embodiments of the invention are shown in the figures. The figures, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them into further meaningful combinations.

(2) In the Exemplary Figures:

(3) FIG. 1 shows an exemplary embodiment of a container of a solar radiation receiver which is driven by a chain;

(4) FIG. 2 shows a schematic representation of a detection of a height profile on a measurement line;

(5) FIG. 3 shows a schematic representation of a detection of a height profile in a region of successive measurement lines in a circumferential direction according to FIG. 2;

(6) FIG. 4 shows a measuring device according to an exemplary embodiment of the invention, in which a distance measuring device has a displaceable optical device;

(7) FIG. 5 shows a measuring device according to an exemplary embodiment of the invention, in which a distance measuring device has a plurality of optical devices;

(8) FIG. 6 shows a perspective view of a container in a framework with a position transducer on a container according to an exemplary embodiment of the invention;

(9) FIG. 7 shows a detailed view of an arrangement of a magnetic tape of the position transducer according to FIG. 6 on a bearing flange of the container;

(10) FIG. 8 shows a detailed view of an arrangement of the position transducer with sensor and magnetic tape according to FIG. 6;

(11) FIG. 9 shows a detailed view of a magnetic tape of a position transducer on a flange of a container according to an exemplary embodiment of the invention;

(12) FIG. 10 shows a detailed view of the position transducer on a flange of a container according to FIG. 9;

(13) FIG. 11 shows, in a cut-away perspective view, a container in a framework with an optical device on a holder according to an exemplary embodiment of the invention;

(14) FIG. 12 shows a flow chart for carrying out a method according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION

(15) In the figures, identical or identically acting components are identified by the same reference signs. The figures only show examples and are not to be understood as limiting.

(16) Before the invention is described in detail, it should be pointed out that it is not limited to the respective components of the device and the respective method steps, since these components and methods can vary.

(17) The terms used herein are only intended to describe particular embodiments and are not used in a limiting manner. Furthermore, if the singular or indefinite articles are used in the description or in the claims, this also applies to the plural of these elements, unless the overall context clearly indicates otherwise.

(18) The directional terminology used in the following with terms such as left, right, above, below, in front of, behind, after, and the like only serves for better comprehension of the figures and is in no way intended to restrict the generality. The components and elements shown, their design and use can vary according to the considerations of a person skilled in the art and can be adapted to the respective applications.

(19) FIG. 1 shows an exemplary embodiment of a container 120 of a solar radiation receiver 100 which is driven by a chain (not shown).

(20) The container 120 is double-walled and has an inner wall 130 on which a film 152 of a heat transfer medium 150, for example bauxite particles, moves through the container 120 during intended operation. Along the axial extent 162 of the container 120, the film 152 is strongly heated by the solar radiation 112 entering through the aperture 126 for radiation input. The heat transfer medium 150 is fed in, for example, via the medium inlet 124 on the opposite side of the container 120 in a manner known per se and is distributed by the rotation of the container 120 on its inner wall 130.

(21) The longitudinal axis 160 of the container 120 can be inclined at an angle 114 with respect to gravity g.

(22) In order to determine the thickness of the film 152, a distance measuring device 10 is used, which comprises at least one optical device 30 with a transmitter 32 and a receiver 34. The optical device 30 is advantageously designed as a profile scanner, with which a measurement line 40 (FIG. 2) is directed onto the object to be measured, for example the inner wall 130 with or without film 152.

(23) FIG. 2 shows a schematic representation of the detection of a height profile by a distance measuring device 10 on a measurement line 40, while FIG. 3 shows a schematic representation of the detection of a height profile on a region 42 of measurement lines 40 following one another in a circumferential direction 140 in accordance with FIG. 2.

(24) The transmitter 32 is conveniently a laser and the receiver 34 is conveniently an electronic camera. The transmitter 32 of the optical device 30 radiates a laser beam onto the inner wall 150, and the receiver 34 measures at points along a measurement line 40 the distances between the optical device 30 and points on the measurement line 40.

(25) During the measurement, the optical device 30 is rigidly mounted, while the container 120 can move in the direction of rotation 170 under the measurement line 40. If the measurement line 40 or the region 42 of measurement lines 40 is positioned above a step in the film 152, the height difference 154 is detected, so that a height profile can be detected with the measurement line 40.

(26) A height profile of the inner wall 130 without the film 152 and a height profile of the inner wall 130 with the film 152 of heat transfer medium 150 can be detected. From the difference in values, the thickness of the film 152 can be determined. A rotational position of the container 120 is determined for each measurement line 40, so that the thickness of the film 152 can be determined with positional precision.

(27) FIG. 4 shows a measuring device 100 according to an exemplary embodiment of the invention, in which a distance measuring device 10 has an optical device 30 that can be displaced on or with a holder 20.

(28) The distribution of heat transfer medium 150 on the inner wall 130 of the container 120 can be determined with the measuring device 100. The measuring device 100 comprises the distance measuring device 10, which in this exemplary embodiment comprises an optical device 30 for detecting at least one height profile along at least one measurement line 40 projected onto inner wall 130, and at least one position transducer 50 for determining a current rotational position of the respective measurement line 40 on the inner wall 130 with respect to the rotational position of the container 120.

(29) The measurement line 40 extends parallel to a longitudinal axis 160 of the container 120. If the container 120 rotates, adjacent measurement lines 40 form a region 42, as schematically shown in FIG. 3.

(30) The position transducer 50 is attached to the container 120 and detects the rotational position of the container 120, in particular synchronously with the projected measurement line 40 in a measuring position. The position transducer 50 can forward the position values to the distance measurement device 10 or, as indicated in the figure, to a computing device 90, which links the distance measurement values and the position values.

(31) It goes without saying that the measured values can be transmitted from the position transducer 50 to the optical device 30 and/or to the computing unit 90, as indicated by dot-dashed lines in FIGS. 4 and 5, by wire via data cables or also wirelessly.

(32) Since the container 120 cannot be driven by a shaft the angular position of which could be detected when the container 120 rotates, the position transducer 50 has a magnetic tape 52 which is placed around the container 120. In order to determine the rotational position, the magnetic tape 52 has a number of magnetic poles, which are read out by a sensor 54 of the position transducer 50.

(33) In order to also detect the distribution of the heat transfer medium 150 on the entire inner wall 130 of the container 120 in the direction of the longitudinal axis 160, the optical device 30 can be shifted parallel to the longitudinal axis of the container 120 to a new measurement position.

(34) FIG. 5 shows a measuring device 100 according to an exemplary embodiment of the invention, in which, in contrast to the exemplary embodiment in FIG. 4, a distance measuring device 10 has a plurality of optical devices 30, in this example three optical devices 30. The number of optical devices 30 can be advantageously selected such that their measurement lines 40 projected onto the inner wall 130 or the film 152 adjoin one another in the direction of the longitudinal axis 160 of the container 120 and cover the entire axial extension 162 thereof. The optical devices 30 can then remain at their respective measuring point when determining the distribution of the heat transfer medium 150 on the inner wall 130.

(35) FIG. 6 shows a perspective view of a container 120 in a framework 200 with a position transducer 50 on the container 120 according to an exemplary embodiment of the invention. FIG. 7 shows a detailed view of an arrangement of a magnetic tape 52 of the position transducer 50 according to FIG. 6 on a bearing flange 132 of the container 120. FIG. 8 shows a detailed view of an arrangement of the position transducer 50 with sensor 54 and magnetic tape 52 according to FIG. 6.

(36) The container 120 has no shaft for the rotation of the container 120 during normal operation. The container 120 is driven, for example, by a chain drive, for which purpose the container 120 in this example has a flange 134 with a crown gear 136, into which a chain (not shown) can engage in order to rotate the container 20. A bearing flange 132 is arranged on the container 120 at an axial distance therefrom.

(37) The container 120 is mounted and guided in the framework 200 by the bearing flange 132. For example, the container 120 has the bearing flange 132 at one axial end and the flange 134 with the crown gear 136 at the opposite axial end.

(38) The magnetic tape 52 can be arranged on the bearing flange 132 of the container 120 with which the container 120 is supported in the framework 200.

(39) The magnetic tape 54 can be fastened to the bearing flange 132 on an outer side of a suitably bent holding sheet plate 60, for example made of aluminum, and enclose the container 120 on its outer side. The holding sheet plate 60 can be arranged, for example, in a free space on the inside of the bearing flange 132.

(40) The holding sheet plate 60 can consist of or comprise individual parts that are bent on a bending machine. The holding sheet plate 60 can then be fastened to the inside of the bearing flange 132, for example by gluing. Then the magnetic tape 52 can be fastened to the holding plate 60, for example by gluing, or fixed with a tightening strap or in another suitable manner.

(41) The sensor 54 is mounted at a small distance from the magnetic tape 52. An advantageous distance is in particular between 1 mm and 3 mm. For this purpose, the sensor 54 can be arranged on a holding arm 56 which points towards the magnetic tape 52 and is fixed to the framework 200 (FIG. 6). In this way, the sensor 54 can be positioned in a stable and reproducible manner in relation to the magnetic tape 52.

(42) The connections of holding arm 56 and sensor 54 to the framework 200 can advantageously be detachable and can be designed, for example, as screw connections.

(43) FIG. 9 shows a detailed view of a magnetic tape 52 of a position transducer 50 on a drive flange 134 of a container 120 according to an exemplary embodiment of the invention. FIG. 10 shows a detailed view of the position transducer 50 on the drive flange 134 of the container 120 according to FIG. 9.

(44) The drive flange 134 is part of the container 120 itself. In this embodiment, the magnetic tape 52 is attached to the outside of the drive flange 134, for example by gluing.

(45) The sensor 54 is mounted at a small distance from the magnetic tape 52. An advantageous distance is in particular between 1 mm and 3 mm. For this purpose, the sensor 54 can be arranged on a holding arm 56 which points towards the magnetic tape 52 and which is fixed to the framework 200 (FIG. 10). In this way, the sensor 54 can be positioned in relation to the magnetic tape 52 in a stable and reproducible manner.

(46) The connections of the holding arm 56 and the sensor 54 to the frame 200 can advantageously be detachable and can be designed, for example, as screw connections.

(47) It goes without saying that the magnetic tape 52 can also be arranged at a different location on the container 120.

(48) FIG. 11 shows a cut-out perspective view of a container 120 in a framework 200 with an optical device 30 of a distance measuring device 10 on a holder 20 according to an exemplary embodiment of the invention.

(49) The holder 20 protrudes into the interior of the container 120 with an arm 22 pointing in the axial direction of the container 120. The optical device 30 is fastened to the arm 22, for example by screwing, tying, clamping or the like.

(50) The arm 22 is attached to a crossbeam 24 located in front of the aperture 126 of the container 120 and attached to the framework 200. Typically, during the operation of the container 120, solar radiation is directed into the container 120 through the aperture 126.

(51) In particular, the crossbeam 24 can extend from one side of the framework 200 to the other side and cover the aperture 126.

(52) The optical device 30 can be arranged to be displaceable along the arm 22. Alternatively or additionally, the arm 22 can be arranged to be displaceable on the crossbeam 24.

(53) Alternatively or additionally, the arm 22 can also be designed as a telescopic arm.

(54) All connections of the arm 22 are expediently designed as detachable connections, so that the aperture 126 can be freed again after the measurements.

(55) FIG. 12 shows a flow chart for carrying out a method according to an exemplary embodiment of the invention.

(56) The method for determining a distribution of heat transfer medium 150 on an inner wall 130 of a container 120 starts with step S100.

(57) In a first sequence S200, a first measurement takes place, in which the inner wall 130 of the container 120 is measured. In step S202, the optical device 30 of the distance measuring device 10 measures the distances between the optical device 30 and points on the measurement line 40 on the inner wall 130, point by point along a measurement line 40, while the position transducer 50 measures the rotational position of the container 120 (step S204). A first three-dimensional point cloud is generated in step S206 by linking distance and rotational position. The respective distance in relation to the respective measurement line 40 results in a height profile of the inner wall 130 both in the direction of the longitudinal axis 160 of the container 120 and, since the container 120 rotates, in the circumferential direction 140.

(58) A second measurement takes place in a second sequence S300, in which the film 152 of the heat transfer medium 150, which is distributed on the inner wall 130, is measured. In step S302, the optical device 30 of the distance measuring device 10 measures the distances between the optical device 30 and points on the measurement line 40 on the film 152, point by point along a measurement line 40, while the position transducer 50 measures the rotational position of the container 120 (step S304).

(59) A further three-dimensional point cloud is generated in step S306 by linking distance and rotational position. The respective distance in relation to the respective measurement line 40 results in a height profile of the film 152 on the inner wall 130 both in the direction of the longitudinal axis 160 of the container 120 and, since the container 120 rotates, in the circumferential direction 140.

(60) It goes without saying that the measurement on the inner wall 130 can also be carried out after the measurement on the film 152, so that the two sequences S200 and S300 can be swapped.

(61) In step S402, in sequence S400, a difference between the distance from the measurement on the inner wall 130 of the container 120 without heat transfer medium 150 and the distance from the measurement on the film 152 on the inner wall 130 is formed for each measuring point. In step S404 a corrected point cloud is provided.

(62) After sequence S400, in step S500, measured values for the thickness of the film 152 corresponding to the distribution of the heat transfer medium 150 on the inner wall 130 are provided at a defined number of measuring points. The thickness of the film 152 or the distribution of the heat transfer medium 150 on the inner wall 130 can be determined with high spatial resolution.

(63) The method ends in step S600.

(64) The distance measurements are made without solar radiation entering the container 120. The measurements are expediently carried out at comparable temperatures.

(65) Furthermore, corrections can be made during a reference measurement and during the measurement on the film 152 if the container 120 has deviations from circularity and/or an eccentricity. In particular, the measurement lines 40 can be adapted.

(66) The determination of the distribution of heat transfer medium 150 on the inner wall 130 can be carried out repeatedly at time intervals for quality control and any changes in the distribution can be detected. If permissible tolerances of the changes are exceeded, a maintenance requirement can be indicated.

LIST OF REFERENCE NUMERALS

(67) 10 distance measuring device 20 holder 22 arm 24 crossbeam 30 optical device 32 transmitter 34 receiver 40 measurement line 42 region 50 position transducer 52 magnetic tape 54 sensor 56 arm 60 holding sheet plate 90 computing device 100 receiver device 112 solar radiation 114 angle 120 container 122 housing 124 medium inlet 126 aperture 130 inner wall 132 bearing flange 134 drive flange 136 crown gear 140 circumferential direction 150 heat transfer medium 152 film 154 height difference 160 longitudinal axis 162 axial extent 170 direction of rotation 200 framework