Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
A FASTENER AND A FASTENING ELEMENT FOR SECURING A MIRROR TO A SUPPORT OF A PARABOLIC SOLAR REFLECTOR
Document Type and Number:
WIPO Patent Application WO/2018/151656
Kind Code:
A1
Abstract:
A fastener for securing a mirror (111) of a parabolic solar reflector (110) to a support (120) of said parabolic solar reflector (111) by receiving a fastening element (210) comprising a shaft (211) having a locking ring (215) around its circumference is provided. The fastener (220) comprises a collar (240) having at least a partly conical shaped aperture (241), wherein the at least a partly conical shaped aperture (241) comprise a circumferential edge (242) adapted to cooperate with the locking ring (215) in order to prevent the shaft (211) from leaving the collar (240) once the shaft (211) has been inserted into the collar (211). Also, a fastening element (210) for securing a mirror (111) of a parabolic solar reflector (110) to a support (120) of said parabolic solar reflector (111) by being received in a fastener (220) comprising a collar (240) having at least a partly conical shaped aperture (241) with a circumferential edge (242) is provided. The fastening element comprises a shaft (211) having a locking ring (215) around its circumference, wherein the locking ring (215) is adapted to cooperate with the circumferential edge (242) in order to prevent the shaft (211) from leaving the collar (240) once the shaft (211) has been inserted into the collar (211). Furthermore, a mirror and a parabolic solar reflector are also provided.

Inventors:
WEBER, Peter (Murarns väg 8, Gråbo, 443 72, SE)
HERTIN, Andreas (Halleby 201, Jörlanda, 444 92, SE)
Application Number:
SE2018/050145
Publication Date:
August 23, 2018
Filing Date:
February 14, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CLEANERGY AB (Regnbågsgatan 6, Göteborg, 417 55, SE)
International Classes:
F16B21/18; F16B9/02; F16B21/08; F24S25/60; F24S23/71; G02B7/192
Foreign References:
US4501469A1985-02-26
EP0649994A11995-04-26
CN202676974U2013-01-16
Attorney, Agent or Firm:
BERGENSTRÅHLE & PARTNERS GÖTEBORG AB (Lindholmspiren 5A, Göteborg, SE-417 56, SE)
Download PDF:
Claims:
A fastener (220) for securing a mirror (1 1 1 ) of a parabolic solar reflector (1 10) to a support (120) of said parabolic solar reflector (1 1 1 ) by receiving a fastening element (210) comprising a shaft (21 1 ) having a locking ring (215) around its circumference, wherein the fastener (220) comprises

a collar (240) having at least a partly conical shaped aperture (241 ), wherein the at least a partly conical shaped aperture (241 ) comprise a circumferential edge (242) adapted to cooperate with the locking ring (215) in order to prevent the shaft (21 1 ) from leaving the collar (240) once the shaft (21 1 ) has been inserted into the collar (240).

The fastener (220) according to claim 1 , wherein the at least a partly conical shaped aperture (241 ) of the collar (240) is widest where the shaft (21 1 ) enters the at least partly conical shaped aperture (241 ) and then narrows further into the at least partly conical shaped aperture (241 ).

The fastener (220) according to claim 1 or 2, further comprising a mounting plate (230) having a central aperture (233) in and about which the collar (240) is mounted.

The fastener (220) according to claim 3, wherein the mounting plate (230) comprise a cavity (232) for housing the collar (240) between the mounting plate (230) and the back (1 13) of said mirror (1 1 1 ).

The fastener (220) according to claim 3 or 4, wherein the mounting plate (230) is adapted to be adhered to or mechanically attached onto the back (1 13) of the mirror (1 1 1 ).

The fastener (220) according to any of claims 3-5, further comprising a supporting disc (260) surrounding the central aperture (233) of the mounting plate (230).

7. A fastening element (210) for securing a mirror (1 1 1 ) of a parabolic solar reflector (1 10) to a support (120) of said parabolic solar reflector (1 1 1 ) by being received in a fastener (220) comprising a collar (240) having at least a partly conical shaped aperture (241 ) with a circumferential edge (242), wherein the fastening element comprises

a shaft (21 1 ) having a locking ring (215) around its circumference, wherein the locking ring (215) is adapted to cooperate with the circumferential edge (242) in order to prevent the shaft (21 1 ) from leaving the collar (240) once the shaft (21 1 ) has been inserted into the collar (21 1 ).

The fastening element (210) according to claim 7, wherein the shaft (21 1 ) comprise at least a partly conical shaped end-section (217).

The fastening element (210) according to claim 7 or 8, wherein the locking ring (215) is comprised in a recess (216) in the shaft (21 1 ) such that the locking ring (215) is able to be moved past the circumferential edge (242) of the at least a partly conical shaped aperture (241 ) and cooperate with the circumferential edge (242) to prevent the shaft (21 1 ) from leaving the collar (240) once the shaft (21 1 ) has been inserted into the collar (240).

0. The fastening element (210) according to any of claims 7-9, further comprising a mechanical spring (212) arranged around the circumference of the shaft (21 1 ) which, when the shaft (21 1 ) has been inserted into the collar (240), is adapted to exert a force upon the fastener (220) in order to secure the fastening element (210) in the fastener (220).

1 . The fastening element (210) according to claim 10, wherein the mechanical spring (212) is supported by a circumferential edge (213) around the shaft (21 1 ).

2. The fastening element (210) according to any of claims 7-1 1 , wherein the shaft (210) comprise a threaded section (214) such that the shaft (210) is able to be screwed onto the support (120).

13. The fastening element (210) according to claim 12, wherein the threaded section (214) of the shaft (21 1 ) is a located at a mid-section of the shaft (21 1 ).

14. A mirror (1 1 1 ) comprising a fastener (220) according to any of claims 1 -6.

15. A parabolic solar reflector (110) comprising one or more mirrors (111) secured to a support (120) by one or more fasteners (220) according to any of claims 1-6 and/or one or more fastening elements (210) according to any of claims 7-13.

Description:
A FASTENER AND A FASTENING ELEMENT FOR SECURING A MIRROR TO A SUPPORT OF A PARABOLIC SOLAR REFLECTOR

TECHNICAL FIELD

5 Embodiments herein relate to fasteners and fastening elements. In particular, embodiments herein relate to fastener and fastening elements for securing a mirror to a support of a parabolic solar reflector. Also, embodiments herein relate to a mirror comprising one or more fasteners and a parabolic solar reflector comprising one or more mirrors being secured to a support of a parabolic solar reflector by one or more fasteners o and one or more fastening element.

BACKGROUND

Concentrated Solar Power, CSP, systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a small 5 area. Energy from the concentrated area may thereafter be converted to electrical energy.

In systems comprising a parabolic solar reflector, a single parabolic reflector focuses solar thermal energy toward a focal point. Traditional parabolic solar reflectors often comprise a large parabolic mirror mounted to a vertical support. Alternatively, a0 parabolic solar reflector may also comprise several smaller mirrors, wherein each small mirror is mounted such that the small mirrors form a single parabolic reflector as a whole. The mirrors may be fastened to a support with its reflective side being angled towards the focal point of the parabolic solar reflector. 5 Since the parabolic solar reflectors are often placed in locations that may

experience extreme weather conditions in order to receive as much sunlight as possible, such as, e.g. hot deserts or cold arctic areas, they must be made to endure these kind of harsh environments. One example is that winds may cause the structure of the parabolic solar reflector to cringe and sway and making the mirrors move, vibrate or shake, and0 consequently causing the mirrors to get damaged or break. Another example is that large temperature differences may cause the mirrors of a parabolic solar reflector to thermally expand and crack around its fastening points. A further example is that smaller objects, such as, e.g. debris or sand, may be taken by the wind and get smashed against the mirrors causing the mirrors to be worn down or break. While improvements of the durability of the mirrors may be made, there will almost certainly always be mirrors that gets worn or broken and thus needs to be replaced.

When replacing damaged or broken such mirrors, mounting and securing a new mirror to a support of a parabolic solar reflector may be a time-consuming and arduous task. Furthermore, it may also be difficult to mount the mirror at the right angle due to a high accuracy requirement in focusing the reflected sunlight of the mirror toward the focal point.

SUMMARY

It is an object of embodiments herein to prevent mirrors fastened to a support of a parabolic solar reflector from getting damaged or break.

According to a first aspect of embodiments herein, the object is achieved by a fastener for securing a mirror of a parabolic solar reflector to a support of said parabolic solar reflector by receiving a fastening element comprising a shaft having a locking ring around its circumference. The fastener comprises a collar having at least a partly conical shaped aperture. The at least a partly conical shaped aperture comprise a circumferential edge adapted to cooperate with the locking ring in order to prevent the shaft from leaving the collar once the shaft has been inserted into the collar.

According to a second aspect of embodiments herein, the object is achieved by a fastening element for securing a mirror of a parabolic solar reflector to a support of said parabolic solar reflector by being received in a fastener comprising a collar having at least a partly conical shaped aperture with a circumferential edge. The fastening element comprises a shaft having a locking ring around its circumference, wherein the locking ring is adapted to cooperate with the circumferential edge in order to prevent the shaft from leaving the collar once the shaft has been inserted into the collar.

By having a fastener and a fastening element as described above, the shaft of the fastening element may be easily guided into the fastener. This means that a mirror comprising the fastener may be mounted and secured from the front of the parabolic solar reflector onto the support via the fastening element; that is, the mirror may be mounted and secured to the support without a clear line of sight of the fastening element or the fastener, or having to mount the mirror on the support from behind the parabolic solar reflector. Hence, an improved fastening of a mirror to a support of a parabolic solar reflector is provided. This will prevent mirrors fastened to a support of a parabolic solar reflector from getting damaged or break.

In some embodiments, the at least a partly conical shaped aperture of the collar is widest where the shaft enters the at least partly conical shaped aperture and then narrows further into the at least partly conical shaped aperture. This means that the at least partly conical shaped aperture will guide the shaft into and towards the centre of the aperture, thus allowing the locking ring to be moved into a position in which it may cooperate with the circumferential edge of the partly conical shaped aperture and prevent the shaft from leaving the collar.

The fastener may, according to some embodiments, further comprise a mounting plate having a central aperture in and about which the collar is mounted. This allows the collar to be suspended in the centre of the fastener and fastened to the mirror since the mounting plate may also be adapted to be mounted onto the back of the mirror. In some embodiments, the mounting plate may comprise a cavity for housing the collar between the mounting plate and the back of said mirror. This will create a space between the back of the mirror and the mounting plate into which the shaft of the fastening element may extend when being inserted and fastened. In some embodiments, the mounting plate may be adapted to be adhered to or mechanically attached onto the back of the mirror. This enables the fastener to be attached to the back of the mirror is several different ways.

The fastener may, according to some embodiments, further comprise a supporting disc surrounding the central aperture of the mounting plate. The supporting disc may cooperate with a mechanical spring of the fastening element in order to secure the fastening element in the fastener.

The shaft of the fastening element may, according to some embodiments, comprise at least a partly conical shaped end-section. This allows the shaft to be easily guided by the at least partly conical shaped aperture of the collar while being inserted into the fastener. Furthermore, the fastener and the fastening element also provides a flexible locking mechanism in that the locking ring and the at least partly conical shaped end- section of the fastening element allows for an angle offset of the fastening element. In some embodiments, the locking ring of the fastening element may be comprised in a recess in the shaft such that the locking ring is able to be moved past the circumferential edge of the at least a partly conical shaped aperture and cooperate with the

circumferential edge to prevent the shaft from leaving the collar once the shaft has been inserted into the collar. This provides an easy snap-in locking mechanism wherein the locking ring may be compressed into the recess while being guided in the at least partly conical shaped aperture, and then expand once passed the circumferential edge of the collar. The recess may also hold the locking ring in place prior to the fastening element being inserted into the collar of the fastener.

The fastening element may, according to some embodiments, further comprise a mechanical spring arranged around the circumference of the shaft which, when the shaft has been inserted into the collar, is adapted to exert a force upon the fastener in order to secure the fastening element in the fastener. When the shaft has been inserted and the locking ring has passed the circumferential edge, the mechanical spring may provide a force attempting to pull the shaft out of the collar, thus ensuring that the locking ring engages with the circumferential edge and provides a tight lock. In some embodiments, the mechanical spring may be supported by a circumferential edge around the shaft. This serves to hold the mechanical spring into place prior to the fastening element being inserted into the collar of the fastener and provides a way to enable the mechanical spring to exert the force upon the fastener.

The shaft of the fastening element may, according to some embodiments, further comprise a threaded section such that the shaft is able to be screwed onto the support. This enables an easy way to mount the shaft onto said support. In some embodiments, the threaded section of the shaft may be a located at a mid-section of the shaft. This allows the fastening element to be screwed into and all the way through the support for enabling an adjustment of the fastening element from behind the support, and thus enable an easy adjustment of the angle of the mirror.

According to a third aspect of embodiments herein, the object is achieved by a mirror comprising a fastener as described above. According to a fourth aspect of embodiments herein, the object is achieved by a parabolic solar reflector comprising one or more mirrors secured to a support by one or more fasteners as described above and/or one or more fastening elements as described above. BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the embodiments will become readily apparent to those skilled in the art by the following detailed description of exemplary embodiments 5 thereof with reference to the accompanying drawings, wherein:

Fig. 1 illustrates a side-view of embodiments of a concentrated solar power system comprising a parabolic solar reflector, o Fig. 2 illustrates a cross-sectional view of embodiments of a fastening element and a fastener,

Fig. 3 illustrates a cross-sectional view of embodiments of a fastener and a side- view of embodiments of a fastening element,

5

Fig. 4 illustrates cross-sectional views of embodiments of a fastening element and a fastener,

Fig. 5 illustrates general views of embodiments of a fastening element and a0 fastener.

DETAILED DESCRIPTION

In the following, a detailed description of the different embodiments of a fastener and a fastening element is disclosed with reference to the accompanying drawings. All5 examples herein should be seen as part of the general description and are therefore possible to combine in any way in general terms. Individual features of the various embodiments and methods may be combined or exchanged unless such combination or exchange is clearly contradictory to the overall function. 0 In Fig. 1 , a concentrated solar power system 100 is shown from a side view showing the concentrated solar power system 100 in the way that the system is normally visible when deployed and in use. The concentrated solar power system 100 comprises a parabolic solar reflector 1 10 and a support 120 for the parabolic solar reflector 1 10. The parabolic solar reflector 110 may comprise one or more mirrors 1 11. The mirror of the5 parabolic solar reflector 110 are arranged on the support 120 such that their reflective sides are angled towards the focal point of the parabolic solar reflector 110. It is understood that any further parts of the concentrated solar power system 100 are not relevant to the description of the embodiments herein and are therefore not described in more detail herein.

Fig. 2 illustrates a cross-sectional view of embodiments of a mirror 11 1 , a fastening element 210 and a fastener 220. The mirror 11 1 comprises a reflective side 1 12, or front side, and a back side 113. The fastener 220 is attached to the back side 113 of the mirror 11 1.

The fastener 220 may comprise a mounting plate 230, a collar 240, protective discs 250, 251 , and a supporting disc 260. The mounting plate 230, the collar 240 and the supporting disc 260 may be made of a metal, such as, e.g. steel.

The mounting plate 230 may comprise a circumferential edge 231 , a cavity 232 and a central aperture 231. The circumferential edge 231 may be arranged to be tightly fixed to the back side 1 13 of the mirror 1 11. The circumferential edge 231 may, for example, be adhered to the back side 113 of the mirror 11 1 using any suitable adhesive or glue. Alternatively, the circumferential edge 231 may, for example, comprise one or more holes in order to allow the mounting plate 230 to be screwed or nailed tightly onto the back side 113 of the mirror 111. The shape of the mounting plate 230 may provide a cavity 232 between the back side 113 of the mirror 11 1 and the mounting plate 230. The cavity 232 may be adapted such that the mounting plate 230 may house the collar 240. The cavity 232 is also adapted such that the space between the back side 1 12 of the mirror 11 1 and the mounting plate 230 is large enough in order to enable a shaft 211 of the fastening element 210 to extend into the space, when being inserted and fastened into the fastener 220, without coming into contact with the back side 1 13 of the mirror 1 11.

The collar 240 may be arranged to extend through the central aperture 233 of the mounting plate 230; that is, the collar 240 may be mounted in and about the central aperture 233 of the mounting plate 230. A first protective disc 250 may be arranged between the collar 240 and the mounting plate 230. The first protective disc 250 may extend around the central aperture 233 of the mounting plate 230. A second protective disc 251 may be arranged on the outside of the cavity 232 of the mounting plate 230 between the mounting plate 230 and a supporting disc 260. The second protective disc 251 and the supporting disc 260 may extend around the central aperture 233 of the mounting plate 230. The first and second protective discs 250, 251 may be made of a soft material, such as, rubber or plastic. A more detailed description of the collar 240 is provided below with reference to Fig. 3.

The fastening element 210 comprise a shaft 21 1 having a first end being adapted to be inserted into and fastened in the collar 240 of the fastener 220 and a second end being 5 adapted to be inserted into and fastened in the support 120 of the parabolic solar reflector 1 10. The fastening element 210 may also be referred to as an adjustment screw, since by screwing the fastening element 210 in or out of the support 120 the angle of the mirror 1 11 may be adjusted.

The shaft 211 may also comprise a threaded section 214. The threaded section 214 o allows the shaft 21 1 to be screwed into the support 120. The support 120 may comprise a hole arranged with a receiving threaded part 121. The receiving threaded part 121 may be arranged to receive and engage with the threaded section 214 of the shaft 211 in order to secure the shaft 211 in the support 120. The threaded section 214 may be located at a mid-section of the shaft 21 1. This enables the fastening element 210 to extend beyond 5 the treaded section 214 and all the way through the support 120. This allows a section of the shaft 11 1 to protrude out of the support 120 on the back of the parabolic solar reflector 1 10. This section of the shaft 11 1 may then be used to adjust how far into the support 120 the shaft 11 1 of the fastening element 210 should be inserted. This enables the angle of the mirror 1 11 to be easily adjusted after being mounted on the support 120 using the0 fastening element 210 and the fastener 220.

The fastening element 210 may further comprise a mechanical spring 212 and a circumferential edge 213 around the shaft 21 1. When the shaft 211 of the fastening element 210 is inserted into the collar 240 of the fastener 220, as shown in Fig. 1 , the mechanical spring 212 may be compressed between the circumferential edge 213 and the5 supporting disc 260 of the fastener 220. Thus, the mechanical spring 212 may exert a force onto the fastener 220 attempting to pull the shaft 211 out of the collar 240. This force may aid in securing a tight lock of the fastening element 210 in the fastener 220. In doing so, the mechanical spring 212 of the fastening element 210 also compresses the first and second protective discs 250, 251 between the collar 240, the mounting plate 2300 and the supporting disc 260 such that there is no gap therein between that may cause vibrations or rattling.

In another example, the circumferential edge 213 may be replaced by extending the threaded section 214 towards the first end of the shaft 11 1 and having a threaded nut (not shown) providing the support for the mechanical spring 212. A more detailed description of the first end of the shaft 11 1 being adapted to be inserted into and fastened in the collar 240 of the fastener 220 is provided below with reference to Fig. 3.

Fig. 3 illustrates a cross-sectional view of embodiments of a fastener 220 and a 5 side-view of embodiments of a fastening element 210.

As shown in Fig. 3, the collar 240 of the fastener 220 may be adapted to guide the shaft 211 of the fastening element 210 by further comprising at least a partly conical shaped aperture 241. For example, the at least a partly conical shaped aperture 241 of the collar 240 may be widest where the shaft 21 1 enters the at least partly conical shaped

1 o aperture 241 and then become narrower further into the at least partly conical shaped aperture 241 before ending at a circumferential edge 242. This means that the at least partly conical shaped aperture 241 may guide the shaft 21 1 into and towards the centre of the at least partly conical shaped aperture 241 when the shaft 21 1 of the fastening element 210 is inserted into the collar 240, as shown by the arrow in Fig. 3.

1 5 The at least a partly conical shaped aperture 241 may comprise a circumferential edge 242. The circumferential edge 242 may be adapted to cooperate with a locking ring 215 of the fastening element 210, as described in more detail below, in order to prevent the shaft 21 1 of the fastening element 210 from leaving the collar 240 once the shaft 211 of the fastening element 210 has been inserted into the collar 240. The circumferential

20 edge 242 and the at least a partly conical shaped aperture 241 thus allowing the locking ring 215 of the shaft 21 1 to be moved and guided into a position in which it may cooperate with the circumferential edge 242 of the partly conical shaped aperture 241 and prevent the shaft 21 1 from leaving the collar 240.

As further shown in Fig. 3, the first end of the shaft 21 1 of the fastening element 210

25 may be adapted to be inserted into in the collar 240 of the fastener 220 by having an at least partly conically shaped end-section 217. This enable the shaft 21 1 to be easily guided by the at least partly conical shaped aperture 241 of the collar 240 while being inserted into the collar 240 of the fastener 220.

Furthermore, the first end of the shaft 21 1 of the fastening element 210 may be

30 adapted to be fastened in the collar 240 of the fastener 220 by comprising a locking ring 215. The locking ring 215 may be circular or semi-circular in shape and may be a rounded or a flat ring. The locking ring 215 may, for example, be made of metal, such as, steel, or rubber. The locking ring 215 may be comprised in a recess 216 in the shaft 21 1. The recess 216 of the shaft 211 may be formed in such a way that it enables the locking ring

35 215 to be moved past the circumferential edge 242 of the at least a partly conical shaped aperture 241 of the collar 240 and cooperate with the circumferential edge 242 to prevent the shaft 21 1 from leaving the collar 240 once the shaft 211 has been inserted into the collar. This provides an easy snap-in locking mechanism wherein the locking ring 215 may be compressed into the recess 216 by, while being guided in, the at least partly 5 conical shaped aperture 241 of the collar 240, and then expand once passed the

circumferential edge 242 of the collar 240. The recess 216 may also be adapted to hold the locking ring 215 in place prior to the fastening element 210 being inserted into the collar 240 of the fastener 220.

It should also be noted that the locking ring 215 allows for the fastening element 210 1 o to turn or rotate in respect to the collar 240, and thus in respect to the fastener 220 and the mirror 1 11. This enables the fastening element 210 to be adjustably screwed into or out of the support 120 while being locked in the fastener 220, and thus further facilitating an easy adjustment of the angle of the mirror 1 11 subsequent to mounting the mirror 11 1 onto the support 120.

1 5

Fig. 4 illustrates cross-sectional views of embodiments of a fastening element 210 and a fastener 220.

The upper left view shows the fastening element 210 being locked in fastener 220. Here, the locking ring 215 of the shaft 21 1 of the fastening element 210 prevents the shaft

20 211 and the fastening element 210 from leaving the collar 240 of the fastener 220, while the mechanical spring 215 applies a force attempting to push the shaft 21 1 of the fastening element 210 out of the collar 240 of the fastener 220, which in combination ensures a tight, yet flexible lock of the fastening element 220 in the fastener 220.

The upper left view shows the fastening element 210 being guided by both the at

25 least partly conical shaped aperture 241 of the collar 240 and the at least partly conical shaped end-section 217 of the shaft 211 into the collar 240 of the fastener 220.

The bottom view shows how the fastener 220 and the fastening element 220 provides a flexible locking mechanism in that the locking ring 215 and the at least partly conical shaped end-section 217 of the fastening element 220 allows for an angle offset, a,

30 between the fastening element 220 and the fastener 210. According to one embodiment, the allowed angle offset, a, may be about 2 degrees. This advantageously provide higher tolerances during manufacturing of the support 120 and the parabolic solar reflector 110 since it reduces the required construction accuracy. Fig. 5 illustrates general views of embodiments of a fastening element 220 and a fastener 210 when being locked in with each other forming a complete mirror attachment.

The terminology used in the detailed description of the particular embodiments

5 illustrated in the accompanying drawings is not intended to be limiting of the described fastening element 210, fastener 220, mirror 1 11 or parabolic solar reflector 100 which instead should be construed in view of the enclosed claims. As used herein, the term "and/or" comprises any and all combinations of one or more of the associated listed items.

Further, as used herein, the common abbreviation "e.g.", which derives from the o Latin phrase "exempli gratia," may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. If used herein, the common abbreviation "i.e.", which derives from the Latin phrase "id est," may be used to specify a particular item from a more general recitation. The common abbreviation "etc.", which derives from the Latin expression "et cetera" meaning "and

5 other things" or "and so on" may have been used herein to indicate that further features, similar to the ones that have just been enumerated, exist.

As used herein, the singular forms "a", "an" and "the" are intended to comprise also the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "includes," "comprises," "including" and/or "comprising," when0 used in this specification, specify the presence of stated features, actions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms comprising technical and scientific terms used5 herein have the same meaning as commonly understood by one of ordinary skill in the art to which the described embodiments belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.0 The embodiments herein are not limited to the above described preferred

embodiments. Various alternatives, modifications and equivalents may be used.

Therefore, the above embodiments should not be construed as limiting.