GB2255195A

GB2255195A - Ball-backed mirror mounted in a conical depression in a wall building compound

Info

Publication number: GB2255195A
Application number: GB9108247A
Authority: GB
Inventors: Martin Farnell
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-04-17
Filing date: 1991-04-17
Publication date: 1992-10-28
Also published as: GB9108247D0

Abstract

At least one ball-backed mirror L1 is mounted in (a) a prism. building brick, block or tile (shown) or (b) a generally cylindrical ceramic or glass bottle having a neck and/or base, (a) or (b) having a conical depression and relieved shoulders. An array of such mirrors may form part of a solar concentrator in association with a heliostat. <IMAGE>

Description

THE BALL 1) socicir COMPOUND SECON\RY PlICl'OR This invention, referred to hereinafter as the Secondary Reflector, consists of hexagonally stacked wall units, the wall being aligned east-west. Each hexagonal unit carries two unloving hexagonal mirrors, aimed at separate targets on either side of the wall. Each and all of the flat, hexagonal mirrors is backed by a ball which protrudes on a stalk. The balls of the mirrors are inserted into shallow-tapering, conical depressions in the ends of the wall units. Rays from the distant, moving (primary) mirrors are aimed, visually and manually, by secondary reflection, at the targets, by swivelling the balls in their sockets.The balls are then pressed firmly into their sockets, where they jam permanently, holding the mirrors fixed.

The compound heliostats shown are not of detailed specification; they are drawn only schetnatically to shou how they relate to the Secondary Reflector optically.

The advantage nf dual solar reflection, over single, is that tie resulting focus is stationary, therefore safer and more manageable.

OiTICAL CONFIGURATION, SCHEMATIC Figs 1 and 2 show the working spatial relationships of the heliostats to the Secondary Reflector in different latitudes.

FIG 1. (Winter, far north or far south of equator). fhe Secondary 12Reflector (A) carries fixed mirrors on both faces, and is here seen end-on. Rays are aimed at the two faces of the wall by means of compound heliostats (n) and (C), the latter being set well back from the Secondary i'eflector so as to be out of its shadow. Two focuses (D and E) are obtained, or a greater number of less intense focuses. The precise position of the focuses is chosen during construction of the Secondary Reflector, whereafter they will not be adjustable unless each facet of the Secondary Reflector is individually re-aimed.

FIG 2. (Equatorial Region). IJere both compound heliostats (F and G) are horizontally deployed, and each is spaced away from the Secondary Reflector (A) so that the latter will shade the heliostats neither in summer nor winter The rays from the heliostats should ideally travel to meet the Secondary Reflector at 450 to the vertical, in the case of horizontal heliostats; so the Secondary Reflector is here shown set up on a foundation of such a height that the Secondary Reflector will intercept the 450 rays from the heliostats.

FIG 3.

FIG. 3, a perspective drawing relating to schematic Fig.l, shows the Secondary Reflector (A), consisting of hexagonally-staclied carriers of flat, fixed hexagonal mirrors. From the compass shown it will be noted that an installation so oriented would be in a location far north of the equator : for a similar installation far south of the eaquator the north-south orientation would be the reverse.

(B) and (J) are the compound heliostats. (E) is the housing for the take-up of focused solar heat.

FnE TYPES OF MIRROR - CARRYING UNIT While the mirror-carrying units making up any one Secondary Reflector will be identical, the design of tlie unit may differ. Five dilferent embodiments of the 'BALL ANI) SOCì;LI' fixing are described below, these types being named 'Dumb-bell' 'Bottle' 'Cup' 'Prick' and 'Tile Cladding' FIGS 4 - 7 : DUSE3-BELL TYPE The dumb-bell unit shown in Fig.4 may be made of any rigid, waterproof material , (e.g. cast concrete).The profiles of the shoulders where they rest against the shoulders of neighbouring dumb-bells may be of hexagonal profile @ or of cylindrical profile N N The depressions at either end of the dumb-bell shown in Fig.5 are conical. Fig.6 shows a detail of the dumb-bell end with its ball-backed mirror installed in its conical socket. Iiere the position of the mirror is close to its limit of angular adjustment.

(L) is a steel re-inforcing bar.

Fig.7 The tep surface of the concrete foundation (Y) is moulded to accept the 1200 corners of the dumb-bell shoulders, so tliat each of the dumb-bells comprising the first course will saddle into place without falling sideways. A subsequent course of dumbbells will saddle into the preceding course, and so on.

After each dumb-bell has been placed in the stack,and the secondary-refleted rays from its two mirrors have been aimed at their respective targets, the ball-backed mirrors are pressed firmly home in their conical sockets, where, given that the taper of the conical socket is sufficiently shallow, they will jam fast. An appropriate cement may be used to guarantee permanence of the fixing.

BOTTLE - TYPE MIRROR CAJURIUR , Figs 8 - 12 The hexaonally-stacking 'Bottle' type of mirror carrier consists of a basically cylindrical-bodied glass or ceramic bottle shown in elevation in Fig.8. The bottle is slightly waisted so that it will contact neighbouring hottles at shoulder and base, thus promoting stability of the hexagonally-stacked 'Bottle' wall. A mid-section of the bottle is shown in Fig.9. The internal surface of the neck (P) and the indent at the base ((z) are conical, and are of such dimensions as to accept the ball-backed mirrors as shown in Figs 10 and 11. Detail of same is shown in Figs 11 A and llB.

FIg.12 : After each bottle unit has been placed in the stack, and after tlie secondary-reflected rays from its two mirrors have been aimed at their respective targets, the two ball-backed mirrors (11 and N) are pressed firmly home into tie conical base-indent and conical neck of the bottle, where they will jam fast.

The top surface of the concrete foundation (R) is moulded to accept the cylindrical sides of the bottle units, so as to prevent rolling about of the bottles of the first course during assembly.

CUP-TYPE MIRROR-CURE ER, Figs 13 - 17 Figs 13 - 17 show a mirror carrier designed to make up a Secondary Reflector that can be attached to an existing wall. 1'it.13 shows an exploded view of the unit. (S) is the ball-backed mirror; (T) is the retaining screw; (U) is the fibre or rubber washer. (V) is the cup unit itself, made of glass or ceramic or any other rigid, weatherproof material. Fig 14 shows a mid section of the cup unit.

Fig 15 shows part of a vertical hexagonal arrangement of the cup units as they would be installed screwed to the vertical surface of a wall.

Fig 16 shows plan, elevation and section of an assembled cup unit with the mirror position corresponding to vertical when attached to a wall. The mirror hexagons are slightly smaller than the hexa gonal bases of the cups, thus allowing clearance (w) between adjacent mirrors.

Fig 17 shows plan, elevation and mid section of an assembled cup unit with the mirror surface inclined at 450. The form of the cup at (V) is such that clearance (X) is allowed between the mirror and the adjacent cup (Y), also clearance (Z) between the mirror and the cup unit it sits in. The latter limitations also obtain in the drawings of the other types of mirror carrier.

BRICK TYPE MIltROR CARRIER Figs 18 and 19 show cubic and cuboid building blocks made of fired clay or concrete, with conical depressions in their sides for accepting ball-backed mirrors of square or rectangular shape.

The surrounds of the conical depressions are relieved, as in the other types, to allow steep angling of the mirrors.

BALL - RtCXID líISROIE Fig. 20shows the ball-backed hexagonal mirrors. Tbese are of solid glass section, metallized on the polished front surface , or may be of solid metal section, polished on the front surface. Fig. 20 A shows ball-backed mirrors of equilateral triangular shape.

TILE CLADDING TYPE Fig 21 shows a wall-cladding tile faced with conical depressions for accepting ball-backed mirrors. This may be considered a compound or joined-together version of the cup type (compare Fig 15). rhe wall cladding tile is shown in plan and elevation mid section in Figs 22 and 23. In Fig 22 , C1 , D1 , E1 , F1, G1 , H1 are mounting holes for screw-fixing to a wall. The type shown here is for mounting hexagonal shaped flat mirrors Fig. 23 shows plan and mid-section elevation of a wall-cladding tile for mounting ball-backed flat mirrors of equilateral triangular shape. Turning momentarily to Fig 24, tLe pattern of triangular mirrors is shown over the dotted profile of the underlying tile.

Noting the position of mirror L1 , and returning to Fig. 25, the same ball-backed mirror L1 is shown swung to the left at an extreme angle. A steep angle of mirror such as this may be necessary in some parts of the Secondary Reflector if a short focus is required, M1 is one of seven holes going clear through the tile. These holes accomodate the points of the triangles when the mirrors are angled steeply (see L1 in Fig 23 Mid Section Elevation.

Claims

Claim 1. A prism, consisting of rigid weatherproof material, with a steeply tapering conical indentation in the centre of either end, these indentations housing and fixing ball-backed flat mirrors of similar shape to, and slightly smaller than, the cross section of the prism, the shoulders of the prism being relieved to allow wide angular adjustment of the mirrors, and the body of the prism being waisted in the middle to promote the stability of prisms when stacked to make a wall.
Claim 2. A cylindrical bodied ceramic or glass bottle, the neck of which has a steeply tapering internal surface, and the base of which has a similarly steeply tapering conical indent (neck and base being for mirror attachment as in Claim 1.); the body of the bottle being slightly waisted to promote the stability of a hexagonal stack of such bottles lying oil their sides; and the shoulders of the bottle relieved as in Claim 1.
Claim 3. A prism, one end only of which has a conical indent and relieved shoulders as in Claim 1; with central trough-hole at tiie bottom of the indent for screw fixing to a wall.
Claim 4. A cubic or cuboid building brick or blocs with conical depression and relieved shoulders as in Claim 3.
Claim 5. A hexagonal, octagonal, or square tile with numerous conical indentations, as in claim 3, the shoulders of each indentation being relieved as in Claim 3.