Heliostat frame and heliostat and heliostat field thereof

Abstract

The application discloses a heliostat mirror frame, which comprises a main beam, a plurality of sub-beams which are arranged at intervals on the main beam, the sub-beams being fixed on the main beam along the extension direction of the central axis of the main beam, and a plurality of support block assemblies arranged on the sub-beams; each support block assembly comprises a support block and a bonding sheet, the support block is connected with the reflecting surface of the heliostat through the bonding sheet, and the height of each support block is set according to the position of the support block on the sub-beam, so that the central line of the top surfaces of the support blocks on the sub-beam is in an arc shape. The heliostat mirror frame provided by the application can guarantee the accuracy of the curved surface of the heliostat, reduce the requirement on the manufacturing accuracy of the sub-beams, effectively reduce the production cost, and improve the manufacturing and processing efficiency.

Description

[0001] This application is a divisional application of Chinese invention patent application number 2020100318043, the original application was filed on January 13, 2020, application number 2020100318043, and the invention title is "A heliostat frame and its heliostat and heliostat field". Technical Field

[0002] This invention belongs to the field of solar thermal power generation technology, and particularly relates to a heliostat frame and its heliostat and heliostat field. Background Technology

[0003] Solar energy, as a clean and renewable energy source, is being used more and more widely. Solar thermal power generation technology is an emerging solar energy utilization technology following photovoltaic power generation technology. Among them, tower solar thermal power generation technology has received widespread attention due to its advantages in energy storage and peak shaving.

[0004] In tower solar thermal power generation, the heliostat's function is to concentrate sunlight onto the receiver, heating the heat-absorbing or heat-storing medium to generate high-temperature, high-pressure steam, which then drives a turbine to generate electricity. The performance of the heliostat frame determines the quality of the sunlight spot, and the quality of the reflected sunlight spot directly affects the efficiency of solar thermal power generation. In tower solar thermal power plants, heliostats are used to concentrate sunlight and reflect it onto the receiver at the top of the tower. Generally, to improve the concentrating effect of the heliostat, its reflecting surface is designed with a specific curvature. Traditionally, heliostats are made by pre-designing and machining a secondary beam to a specific arc, then connecting the reflecting surface to the secondary beam, thus giving the reflecting surface a certain curvature. This requires high precision in secondary beam machining, increasing manufacturing difficulty and consequently cost. Furthermore, in the later stages of use, the curved secondary beam is prone to deformation, causing the reflecting surface to deviate from the theoretically designed curvature, affecting the efficiency of solar thermal power generation. Summary of the Invention

[0005] This invention provides a heliostat frame and a heliostat. The heliostat frame provided by this invention, by setting a support block assembly, can reduce the requirements for the manufacturing precision of the sub-beam while ensuring the surface accuracy of the heliostat, thereby effectively reducing production costs and improving manufacturing efficiency.

[0006] The technical solution of the present invention is as follows:

[0007] A heliostat frame includes a main beam and several secondary beams spaced apart on the main beam. The secondary beams are fixed to the main beam along the central axis of the main beam, and several support block assemblies are provided on the secondary beams.

[0008] The support block assembly includes a support block and an adhesive sheet, and the support block is connected to the reflecting surface of the heliostat via the adhesive sheet;

[0009] The height of each support block is set according to its position on the sub-beam so that the line connecting the centers of the top surfaces of each support block on the sub-beam forms an arc.

[0010] Preferably, the support block is connected to the sub-beam via a fixed connection or a detachable connection.

[0011] Preferably, the sub-beam includes at least one top surface of the sub-beam, and the support block is disposed on the outer surface of the top surface of the sub-beam; or, the support block is embedded in the top surface of the sub-beam.

[0012] Preferably, a first through hole is provided on the top surface of the sub-beam, the support block is embedded in the first through hole, the longitudinal section of the support block is stepped, including a first part of the support block and a second part of the support block, the radial width of the first part of the support block is smaller than that of the second part of the support block, and the first part of the support block is embedded in the first through hole on the sub-beam and connected to the top surface of the sub-beam, and the second part of the support block is connected to the adhesive sheet.

[0013] Preferably, the height of the first part of the support block is less than or equal to the thickness of the top surface of the sub-beam.

[0014] Preferably, the support block is fixedly connected to the sub-beam by means of adhesive bonding, riveting, or welding.

[0015] Preferably, a second through hole is provided at the center of the support block, and a threaded hole is provided at the bottom of the adhesive sheet; the bolt passes through the first through hole of the sub-beam, the second through hole of the support block, and the threaded hole of the adhesive sheet for threaded connection.

[0016] Preferably, an anti-loosening washer is also provided between the bolt and the inner surface of the top surface of the sub-beam.

[0017] Preferably, the top surface of the support block is arranged in a mirror-symmetrical manner along the plane that vertically bisects the top surface of the sub-beam.

[0018] Preferably, the secondary beam includes two side surfaces extending from both sides along the length of the secondary beam.

[0019] Preferably, the sub-beam further includes a bent portion extending from its free end along its lateral length direction.

[0020] Preferably, it also includes a support beam, which includes a top surface and two side surfaces extending from the top surface of the support beam along its length. The top surface of the support beam is provided with a plurality of perforated holes, and the projection of the perforated holes onto the corresponding sub-beam corresponds to the mounting position of the support block on the corresponding sub-beam.

[0021] Preferably, a gasket is provided at the connection between the support beam and the sub-beam, and the support beam is connected to the sub-beam through the gasket. The sum of the thickness of the gasket and the width of the outer sides of the two sides of the support beam is equal to the width of the inner sides of the two sides of the sub-beam.

[0022] Preferably, the adhesive sheet includes a tray for fixed connection with the reflecting surface of the heliostat and a base for supporting the tray, wherein the cross-section of the tray is thicker at the center and gradually thins at the edges in the radial direction.

[0023] Preferably, the tray has a third through hole at its center.

[0024] Preferably, along the length of the same sub-beam, the distance between the two adhesive sheets on both sides of the joint of two adjacent reflective units in the reflective surface is smaller than the distance between two adjacent adhesive sheets at other locations.

[0025] The present invention also provides a heliostat, comprising: a reflecting surface of the heliostat, and a heliostat frame connected to the reflecting surface, wherein the heliostat frame is as described in any of the preceding claims.

[0026] The present invention also provides a heliostat field, including the heliostat as described above.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention sets support blocks on the sub-beam and specially sets the thickness of the support blocks according to their specific positions on the sub-beam, so that the line connecting the centers of the top surfaces of each support block forms an arc shape, such as an arc shape that is low in the middle and high at both ends. This design can effectively reduce the processing accuracy requirements of the sub-beam, thereby reducing manufacturing costs and improving production efficiency. At the same time, since each support block has formed a specific arc, when installing the reflective surface, it is only necessary to connect the reflective surface to the support block at a specific position to quickly form the required reflective surface shape, which effectively simplifies the installation steps.

[0029] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0030] Figure 1 This is an assembled view of the heliostat body of Embodiment 1 of the present invention;

[0031] Figure 2 This is a partial enlarged view of the support unit in Embodiment 1 of the present invention;

[0032] Figure 3 This is an enlarged view of the central support of Embodiment 1 of the present invention;

[0033] Figure 4 This is a cross-sectional view of the secondary beam in Embodiment 1 of the present invention;

[0034] Figure 5 This is a connection diagram of the secondary beam and the support beam in Embodiment 1 of the present invention;

[0035] Figure 6 This is a connection diagram of the support block and the adhesive sheet in Embodiment 1 of the present invention;

[0036] Figure 7 This is a connection diagram of the support block and the adhesive sheet in Embodiment 1 of the present invention.

[0037] The markings in the diagram are: 1-reflective surface, 2-support unit, 21-main beam, 22-central support, 23-sub-beam, 24-support beam, 25-anti-loosening washer, 26-support block, 27-adhesive sheet, 28-shield, 231-top surface of sub-beam, 232-side surface of sub-beam, 233-first through hole, 251-hollow hole, 261-first part of support block, 262-second part of support block, 263-second through hole, 271-bolt, 272-pallet, 273-third through hole, 274-base; 275-threaded hole. Detailed Implementation

[0038] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Improvements and adjustments made by those skilled in the art based on the present invention in practical applications still fall within the scope of protection of the present invention.

[0039] To better illustrate the present invention, a detailed description of the invention is provided below with reference to the accompanying drawings.

[0040] Example 1

[0041] A heliostat frame, see Figure 1 The system includes a support unit 2, which includes a main beam 21 and several secondary beams 23 spaced apart on the main beam 21. The secondary beams 23 are fixed to the main beam along the central axis of the main beam 21, and several support block assemblies are provided on the secondary beams 23.

[0042] The support block assembly includes a support block 26 and an adhesive sheet 27. The support block 26 is connected to the reflecting surface 1 of the heliostat via the adhesive sheet 27.

[0043] The height of each support block 26 is set according to its position on the sub-beam 23, so that the line connecting the centers of the top surfaces of each support block on the sub-beam 23 is arc-shaped.

[0044] In traditional heliostats, to make the reflecting surface of the heliostat form a specific curved surface, the sub-beam needs to be set to a specific curvature during assembly. This design requires extremely high machining precision for the sub-beam, including but not limited to the curvature and surface smoothness of the sub-beam. On the one hand, the sub-beam needs to be machined into a specific curvature; on the other hand, the flatness of the sub-beam surface needs to be precisely controlled so that the curvature of the sub-beam when connected to the reflecting surface is close to the theoretical curvature. The accuracy of assembly is also required to be very high, which greatly increases the manufacturing cost of the heliostat and reduces the installation efficiency. This invention, by setting support blocks 26 on the sub-beam 23 and specifically setting the thickness of the support blocks 26 according to their specific positions on the sub-beam 23, ensures that the line connecting the centers of the top surfaces of each support block 26 forms a specific arc shape, such as an arc that is low in the middle and high at both ends. This design effectively reduces the machining accuracy requirements of the sub-beam 23, thereby reducing manufacturing costs and improving production efficiency. Furthermore, since each support block 26 has already formed a specific arc, when installing the reflective surface 1, it is only necessary to connect the reflective surface 1 to the support block at a specific location to quickly form the required reflective surface shape, effectively simplifying the installation steps. In addition, the thickness of the preset support blocks 26 can be adjusted according to parameters such as the position of the support block 26 on the sub-beam, the flatness of the sub-beam surface at that position, and the theoretically required arc, so that it matches the height required by the theoretical arc, significantly reducing the surface flatness requirements of the sub-beam 23.

[0045] This application does not limit the connection method between the secondary beam 23 and the main beam 21. It can be a connection method found in the prior art, such as the secondary beam 23 being connected to the main beam via existing support seats or support frames, or the secondary beam being directly welded to the main beam. Alternatively, it can employ methods such as... Figure 2 The central support 22 is connected to the main beam. The central support 22 includes two support plates that are spaced apart from each other and arranged in parallel. The two support plates are fixedly connected by at least one support member located between them. Both support plates are provided with through holes to form a central support through hole. The central support 22 is sleeved on the main beam 1 through the central support through hole and is fixedly connected to the main beam 1. The central support 22 is also provided with mounting points for the secondary beam 23 to be installed. The secondary beam is connected to the main beam 1 through the central support 22.

[0046] The secondary beam 23 can be either straight or curved. The thickness of the support block is ultimately set according to the position of the support block on the secondary beam to meet the theoretical curvature requirement of the reflective surface. Whether the secondary beam is straight or curved does not have a practical impact. However, in order to reduce costs, a straight secondary beam can be preferred.

[0047] The connection method between the support block 26 and the sub-beam 23 will be further described below.

[0048] The support block 26 is connected to the sub-beam 23 by a fixed connection or a detachable connection.

[0049] The sub-beam 23 includes at least one sub-beam top surface 231, and the support block 26 is disposed on the outer surface of the sub-beam top surface 231; or, the support block 26 is embedded in the sub-beam top surface 231.

[0050] Here, the connection between the support block 26 and the sub-beam 23 can include four methods:

[0051] Method 1: The support block 26 is fixedly connected to the outer surface of the top surface 231 of the sub-beam; including but not limited to fixing methods such as gluing and welding; the shape of the support block 26 includes but is not limited to block or ring shape; for example, the support block 26 can be a support ring, which is directly glued or welded to the top surface 231 of the sub-beam.

[0052] Method 2: The support block 26 is embedded in the top surface 231 of the sub-beam by a fixed connection method, including but not limited to fixed connection with the sub-beam by riveting, gluing, or welding;

[0053] Method 3: The support block 26 is set on the outer surface of the top surface 231 of the sub-beam in a detachable connection manner; if holes are set at the corresponding positions of the top surface 231 of the sub-beam and the support block 26, the support block 26 is connected to the top surface 231 of the sub-beam by directly passing a bolt through the hole and connecting it with a nut.

[0054] Method 4: The support block 26 is embedded in the top surface 231 of the sub-beam through a detachable connection.

[0055] Regarding the embedding methods of methods 2 and 4, combined with... Figure 6 , Figure 7 The sub-beam 231 has a first through hole 233, and the support block 26 is embedded in the first through hole 233. The longitudinal section of the support block 26 is stepped, including a first part 261 and a second part 262. The radial width of the first part 261 is smaller than that of the second part 262. The first part 261 is embedded in the first through hole 233 on the sub-beam 23 and connected to the top surface 231 of the sub-beam. The second part 262 is connected to the adhesive sheet 27. With this structure, when the support block 26 is embedded in the sub-beam 23, there is no glue or welding material between the outer surface of the top surface 231 of the sub-beam and the bottom surface of the support block 26. This allows for more convenient and accurate control of the height of the support block 26 on the top surface 231 of the sub-beam, thereby making the reflective surface shape of the heliostat more accurate.

[0056] Furthermore, a threaded connection can be used to embed the support block 26 into the top surface 231 of the sub-beam. Specifically, a second through hole 263 is provided at the center of the support block 26, and a threaded hole 275 is provided at the bottom of the adhesive sheet 27; the bolt 271 passes through the first through hole 233 of the sub-beam 23, the second through hole 263 of the support block 26, and the threaded hole 275 of the adhesive sheet 27 for threaded connection. With this design, the reflecting surface 1 can be easily separated from the mirror frame, thereby facilitating the maintenance of the heliostat. In addition, to prevent the bolt 271 from loosening during the long-term operation of the heliostat, an anti-loosening washer 25 can be provided between the bolt 271 and the inner surface of the top surface 231 of the sub-beam. Preferably, the anti-loosening washer 25 can be a double-layered self-locking washer.

[0057] The support block 26 will be described in more detail below.

[0058] The height of the first part 261 of the support block is less than or equal to the thickness of the top surface 231 of the sub-beam. If the height of the first part 261 of the support block is greater than the thickness of the top surface 231 of the sub-beam, the nut or anti-loosening washer will directly abut against the bottom of the base plate of the first part 261 of the support block, causing the sub-beam 23, the adhesive piece 27, and the support block 26 to be unable to be connected as a whole, thus failing to guarantee the reliability of the connection between the three.

[0059] The top surface of the support block 26 is mirror-symmetrically arranged along the plane that perpendicularly bisects the top surface 231 of the sub-beam. Here, "mirror-symmetrical arrangement" refers only to the central symmetry of the top surface of the support block 26; the thickness of the support block 26 is not necessarily mirror-symmetrical. This design ensures that the midpoint of the sub-beam 23 is the lowest point of the reflective surface 1, resulting in a more uniform surface shape and better light-gathering effect.

[0060] The following is a further introduction to sub-beam 23.

[0061] In addition to the top surface 231, the sub-beam may also include at least one side surface located below and connected to the top surface of the sub-beam, such that the sub-beam is T-shaped, L-shaped, or U-shaped.

[0062] See Figure 4 The sub-beam 23 includes two side surfaces extending from both sides along its length, namely, sub-beam side surfaces 232. This design increases the rigidity of the sub-beam itself, preventing deformation after the entire frame is assembled. The two side surfaces extending from both sides along the length of the sub-beam form a bent plate. Given the same thickness, a bent plate with two side surfaces has better rigidity than a bent plate with one side surface or a plate without side surfaces.

[0063] The sub-beam 23 also includes a bent portion 233 extending from its free end along its side length direction. That is, the free end of the side surface 232 of the sub-beam is provided with a bent portion 233. By providing the bent portion 233, the rigidity of the sub-beam 23 can be effectively enhanced, thereby reducing the risk of deformation of the sub-beam 23.

[0064] Furthermore, the support unit 2 also includes support beams 24, one end of each support beam 24 is connected to the main beam 21 and the other end is connected to the secondary beam 23, providing support for the secondary beam.

[0065] Combination Figure 2 , Figure 3 Corresponding to the top surface 231 and side surface 232 of the sub-beam 23, the support beam 24 includes a top surface and two side surfaces extending from both sides along the length of the top surface. The top surface of the support beam 24 has several perforated holes 251. The projection of the perforated holes 251 onto the sub-beam 23 corresponds to the mounting position of the support block 26 on the sub-beam 23. By providing perforated holes 251 on the support beam 24, the wind resistance of the heliostat can be effectively reduced, saving materials and lowering manufacturing costs. Simultaneously, the projection of the perforated holes 251 on the support beam 24 onto the sub-beam 23 corresponds to the mounting position of the support block 26 on the sub-beam 23. This design allows for sufficient installation space for the support block 26 and the bonding sheet 27 during heliostat assembly, facilitating operation.

[0066] For details, see Figure 5 When the support beam 24 is connected to the secondary beam 23, the top surface of the support beam extends into the groove formed by the top surface and side surface of the secondary beam, and the side surface of the support beam connects with the side surface of the secondary beam. A gasket 28 is provided at the connection point between the support beam 24 and the secondary beam 23. The support beam 24 is connected to the secondary beam 23 through the gasket 28. The sum of the thickness of the gasket 28 and the outer width of the two sides of the support beam is equal to the inner width of the two sides of the secondary beam. Due to actual structural limitations, the width of the secondary beam 23 is greater than the width of the support beam 24. When the secondary beam 23 is connected to the support beam 24, the side surface of the secondary beam 23 is prone to deformation. By providing the gasket 28, the width difference between the secondary beam 23 and the support beam 24 can be eliminated, thereby preventing deformation of the secondary beam when connected.

[0067] The adhesive sheet 27 will be described in more detail below.

[0068] See Figure 7The adhesive sheet 27 includes a tray 272 for fixed connection with the reflecting surface 1 of the heliostat and a base 274 for supporting the tray 272. The cross-section of the tray 272 has a radially thicker center and gradually thins towards the edges. This design of the tray 272 prevents excessive stress concentration. Furthermore, since the reflecting surface 1 has a certain curvature, the connection between the tray 272 and the reflecting surface 1, achieved by tightening the bolts 271 used to fix the adhesive sheet 27, allows the tray surface to deform appropriately with the reflecting surface, resulting in a smoother curved surface.

[0069] See Figure 6 The tray 272 has a third through hole 273 at its center. The bonding sheet 27 is generally connected to the reflective surface 1 by applying adhesive to the reflective surface 1 at the position corresponding to the bonding sheet 27, and then adhering the bonding sheet 27 to the corresponding position. When the bonding sheet 27 is bonded to the reflective surface 1, the adhesive applied to the surface of the reflective surface 1 will flow towards the outer edge and the center of the tray 272. In order to ensure that the adhesive layer thickness is consistent at all points between the tray 272 and the reflective surface 1, a third through hole 273 is provided at the center of the tray 272 to hold the excess adhesive flowing to the center of the tray.

[0070] Along the length of the same sub-beam 23, the distance between the two adhesive pieces 27 on both sides of the joint between two adjacent reflective units of the reflective surface 1 is smaller than the distance between two adjacent adhesive pieces 27 at other locations. Because the heliostat's reflective surface has a large area, it is subjected to wind pressure during windy weather, regardless of whether the airflow is from the upper surface to the back surface or vice versa. Since the airflow can only pass through the joint between adjacent reflective units, the edges of the reflective units will vibrate violently. Prolonged and severe vibration can cause the reflective units to break or the connection between the reflective unit and the adhesive pieces to fail. This invention, by reducing the distance between the two adhesive pieces on both sides of two adjacent reflective units, can better limit the vibration of the reflective unit edges, thereby improving the wind resistance of the reflective surface.

[0071] Furthermore, regarding the reflecting surface 1, the aspect ratio of the reflecting surface is 1.2-1.6.

[0072] Example 2

[0073] A type of heliostat, see Figure 1 It includes: a reflecting surface 1 of a heliostat, and a heliostat frame connected to the reflecting surface 1, wherein the heliostat frame is the heliostat frame described in any one of Embodiment 1.

[0074] A heliostat field, comprising the heliostat described above.

[0075] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A heliostat comprising a heliostat frame, comprising a main beam and a plurality of secondary beams spaced apart on the main beam, wherein the secondary beams are fixed to the main beam along the central axis of the main beam, characterized in that, The sub-beam is provided with several support block assemblies; The support block assembly includes a support block and an adhesive sheet, and the support block is connected to the reflecting surface of the heliostat via the adhesive sheet; The height of each support block is set according to its position on the sub-beam, so that the line connecting the centers of the top surfaces of each support block on the sub-beam is arc-shaped. The sub-beam includes at least one top surface of the sub-beam, a first through hole is provided on the top surface of the sub-beam, a second through hole is provided at the center of the support block, and a threaded hole is provided at the bottom of the adhesive sheet; a bolt passes through the first through hole of the sub-beam, the second through hole of the support block, and the threaded hole of the adhesive sheet for threaded connection. The support block is block-shaped or ring-shaped; The adhesive sheet includes a tray for fixed connection with the reflecting surface of the heliostat and a base for supporting the tray; Along the length of the same sub-beam, the distance between the two adhesive sheets on both sides of the joint of two adjacent reflective units in the reflective surface is smaller than the distance between two adjacent adhesive sheets at other locations.

2. The heliostat according to claim 1, characterized in that, The support block is connected to the sub-beam via a fixed connection or a detachable connection.

3. The heliostat according to claim 2, characterized in that, The support block is disposed on the outer surface of the top surface of the sub-beam; or, the support block is embedded in the top surface of the sub-beam.

4. The heliostat according to claim 3, characterized in that, The support block is embedded in the first through hole. The longitudinal section of the support block is stepped, including a first part and a second part. The radial width of the first part is smaller than that of the second part. The first part is embedded in the first through hole on the sub-beam and connected to the top surface of the sub-beam. The second part is connected to the adhesive sheet.

5. The heliostat according to claim 4, characterized in that, The height of the first part of the support block is less than or equal to the thickness of the top surface of the sub-beam.

6. The heliostat according to claim 3 or 4, characterized in that, The support block is fixedly connected to the sub-beam by means of adhesive bonding, riveting, or welding.

7. The heliostat according to claim 1, characterized in that, An anti-loosening washer is also provided between the bolt and the inner surface of the top surface of the sub-beam.

8. The heliostat according to claim 3, characterized in that, The top surface of the support block is mirror-symmetrically arranged along the plane that vertically bisects the top surface of the sub-beam.

9. The heliostat according to claim 3, characterized in that, The sub-beam includes two side surfaces extending from both sides along the length of the sub-beam.

10. The heliostat according to claim 9, characterized in that, The sub-beam also includes a bent portion extending from its free end along its lateral length.

11. The heliostat according to claim 1, characterized in that, It also includes a support beam, which includes a top surface and two side surfaces extending from the top surface of the support beam along its length. The top surface of the support beam is provided with a plurality of hollow holes, and the projection of the hollow holes on the corresponding sub-beam corresponds to the installation position of the support block on the corresponding sub-beam.

12. The heliostat according to claim 11, characterized in that, Gaskets are provided at the connection points of the support beam and the sub-beam. The support beam is connected to the sub-beam through the gaskets. The sum of the thickness of the gasket and the outer width of the two sides of the support beam is equal to the inner width of the two sides of the sub-beam.

13. The heliostat according to claim 1, characterized in that, The cross-section of the tray exhibits a trend of being thicker at the center and gradually thinning at the edges in the radial direction.

14. The heliostat according to claim 13, characterized in that, The tray has a third through hole in the center.

15. A heliostat field, characterized in that, Includes the heliostat as described in any one of claims 1-14.

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