GB Patent 281066 - Improvements in or relating to light-transmitting heat screens for use in cinematograph projectors, and in windows and the like

Description

PATENT SPECIFICATION

Application'Date: oct 28, 1926 No 26,948/26, '81 C fl 11 April 9, 1927 No 9778/27.

,,, June 7, 1927 No 15,049/27, One Complete Left, Aug 18, 1927.

Complete Accepted: Dec, 1, 1927, PROVISIONAL SPECIFICATION,

No Z 6,948, A D 1926.

Improvements in or relatinag to Ligbit-transmitting Heat Screens for use in Cinematograph Projectors, and in Windows and the like I, CI-n I Rf S STUART MCNAIR, of 56, 2 Seel Street, Liverpool, British, do hereby declare the nature of this in vention to be as follows.

6 This invention relates to light screens, windows sky lights or glazed apertures generally, the object of the invention being to provide a glazed panel, screen, or cell which, while permitting the light rays to pass therethrough, will absorb heat from the light The invention is of particuilar use as applied to cinema projectors where it is desirable to shield the highly inflammable filmn from the heat 1 W ays of the lantern arc without detrimentally affecting the illumination of the film Though 1 the invention is particularly suitable for this purpose it is by -no means limited to such use but may be applied generally to the glazing of shop windows, sky lights in roofs or similar situations where it is desiraible to prevent the goods displayed in a window �rom being injured by the heat of the sun' s rays or to keep a workshop cool.

According to this invention the light rays are caused to traverse a cell or cavity enclosed by -lazed discs, sheefs, or the like, the cell or cavity containing a liquid solution of some heat absorbing material such as a solution of alum or carbon 1)isiilphide A solution of alum is very satisfactory and preferably a saturated sohition 'of alum The alum solution 3 r) reduces in only a slight degree the passage of light through the cell and where the light beam, as in the case of a lPr'ice lf-J cinema projector, emanates from an electric arc this slight reduction in intensity may be compensated for by using an 40increased amperage.

As applied to the case of absorbin g heat from the concentrated light beam 'of a cinema projector, I provide a cell consisting say of a metallic cylinder having its 45 ends enclosed by glass discs The cell so formed is filled with a saturated solution of alum and is mounted in any suitable manner, say, on a swinging bracket or otherwise, between the condenser and the 50 O gate" through wbich the film travels intermittently, the cell being so disposed that the conical light beam passes entirely through the alurm solution in the cell It is found that by the use of such a device 55 a co-nsiderably'greater period of time elapses before the film whe-n stationary will fire as compared with the time in which the film would fire if unprotected by the cell 60 The longitudinal depth of the cell may be varied as desired I have found that a cell of from five to seven inches long, is quite sufficient for all practical purposes and that the resulting slight diminution 65 of light may be corrected by the use of only a slightly increased amperage The cell is provided with a fillinog nozzle in the cylindrical wall and such ti Tling, nozzle may be arranged to allow f'or eip'ansion 70 due to the heat absoribed by the solution.

By mounting the cell upon a swing arm or bracket it may be quickly moved into or out of the operative position in order to give facility to the operator for threading his film.

As applied to an ordinary shop window or a sky lio'ht the cell would take the fi form of two sheets of glass spaced apart in this case say a quarter or half inc'h and sealed round theji' peripheries, the cavity between being filled with a -solution of alum or other heat absorbing, material pand the resulting cell 15 eing enclosed in the window frame, or the cell may be built up in place in the window frame and rendered fluid tight rounrd its periphery.

Dated this 27th day of October, 1926 15A J DAVIES, Patent Agent,' 24, Moorfields, Liverpool.

PROVISIONAL SP-ECIFICATION.

No 9778, All) 1927.

improvements in or relating to Light-transmitting Heat Screens for use in -Cinematograph Projectors, and in Windows and the like.

I, CRAR Li S STUART MOINAIR, of 56, metallic salt preferably a copper salt with Seel Street, Liverpool, British-, do -,or without the addition of an iron salt.

hereby declare the nature of this inven 'In preparing the liquid I make a solution to be as follows: tion of alum in water, the water being This invention relates to light-trains raised to a suitable temperature properly mnitting heat screens for cinematograph to ensure solution and to the alum solu-25 projectors, windows, skcy-lights, -or glazed tion after cooling I add a solution of a apertures generally, the object of the curi salt in which latter additional invention being to p rovide a glazed panel, solutipon a ferric salt may also be i-ncorscreen, cell or the like, which while per porated A very small proportion only mkitting the light rays -to pass there of the metallic salt is required relatively through will albsorb heat from the light to the alum content in order to achieve rays Thie invention is of particular us' quite satisatr O rsls as applied to cinem atograph projectors I have found that with this addition to where it is desirable to shield the -highly the liquid of the cell the safe period durinflammable film from the, heat rays of ing which a film wlhen stationary may bhe the lantern without detrimentally affect exposed to the condensed lihtpencils ing the illumination of the film In my from an arc lamp, such as is used in a concurrent Provisiohal Specification No teiiiematograph projector, may be very

26,948-of 1926 I describe a liquid suit much extended without any danger of the able for filling the cell or cavity consist film firing.

ing of a -solution of alum or carbon bisulphide I have found that the heat Dated this 8th day of April, 1927.

absorption qualities of the liquid may be considerably increased -A J DAVIES, With thiis object I incorporate with the Patent Agent, 4,5 solutions of alum a, small -proportion of a 24, -M\oorflelds, Liverpool.

PROVISIONAL -SPECIFICATION.

No 15,049, A ID 1927.

improvements in or-relating to Light-transmitting Heat Screens for use in Cinematograph Projectors, and in Windows and the like.

I Cr-ARL Ea S STUART M ON Aii, -of 56, Seel Sti'eet, Liverpool, -British, do hereby declare the nature of this invention to be as follows 7,5 This invention relates to light-transmitting heat -Screens for ci-nemato graph projectors, -windows, sky-lights, or glazed apertures generally the object of the -invention -being' to provide -a cell, panel, screen, or the like, which while permitting the light rays to pass therethrough will absorb heat from the light rays The -invention is of particular use as applied to cinematograph projectors where it is -desired to -shield the flhn froin the heat rays of the-light beam -without materially affecting the illulmination of the film.

In my conerrent Provisional Specifica s O t i i 1 781,066 281,066 tion No 9778 of 1927 I describe a liq uid for filling the cell or cavity consisting -0 T a solution of alum or carbon bisulphide and a small proportion of a metallic salt S preferably a copper salt.

I have found that a solution of copper sulphate alone is quite effcient for the purpose of absorbing heat from the light rays, and solutions of chloride of copper alone or nitrate of copper alone are also suitable, as are also other soluible salts of copper thoughb not in the same degree as the solution of copper sulphate.

The copper sulphate or other salt of copper may if desired be combined with a solution of alum or carbon bisulphide with or without the addition of an iron salt in the way described in my previous specification above referred to.

As the use of copper sulphate in such a heat absorbing cell colours the liquid therein the resulting screen image is of aslightly blue tint In order to cbunteract this I may add to the liquid in the eell a small proportion of some fadeless dye or stain of a tint which will neutralise the blue tint resulting' from the, copper sulphate and produce a colourless liquid.

Similarly where the colour of the -liquid due to the addition of an iron salt may be of a blue green tint this would' be neutralised Iby the addition of some fadeless, dye or stain which would neutralise the colour Or this neutralization of the tinting of the light from colour in the liquid may be effected by providing tinted glazed panels for the enclosing walls of the cell instead of panels of clear glass; or if the cell be made with clear glass panels, colour screens may be detachably fitted in the path of the light beam in order to correct and neutralise the tint imparted by the liquid in the cell.

Where the colour of the liquid in the cell as in the case of using, copper sulphate is slightly blue the addition of a solution Of cobalt sulphate would tend to -neuttralise the colour.

Dated this 4th day of June, 1927.

A J DJAVIES, Patent Agent, 24, Moorflelds, Liverpool.

COMPLETE SPECIFICATION.

Improvements in or relating to Light-transmitting Heat Screens for use in Cinematograph Projectors, and in Windows and -the like 1, CHARLES STUART Me INAIB, of 56, Seel Street, Liverpool, British, do.

hereby declare the nature of this invention and in what manner the same is to be performned, to be particularly described and ascertained in and by th'e following statement:

This invention relates to light-transmitting heat screens or filters for cinematograph projectors, windows, skylights, or glazed apertures generally, the oibject of -the invention being to provide r a glazed cell panel, screen, or the like, whic'h while permitting the light rays -to pass therethrough will absorb heat from the -light rays The invention is of particular use as applied to cinematograph projectors where it is desirable to shield the highly inflammable film from the heat rays of the lantern without detri mentall-y affecting the illumination of the film Though the invention is -partioni756 flrl sutal for this purpose of shieldingtefl ip a cinemna projector it is by no mans imited to such use but may be applied generally to the glazing ofshop windows, sky lights in:roots or similar situations where it is desirable to {; O -prevent the goods displayed in a window -from being injured by the heat of the sun's rayrs, or to keep a workshop cool.

According to this invention as applied to a heat screen for use wit-h a cinemato 85 graph projector the light rays from the electric arc in the lantern are caused to traverse a cell or receptacle of suitable lengt-h enclosed by glazed discs, sheets or the like, the cell or receptacle containing 90 a solution of copper salt such as copper sulphate which is mixed with a solution of alum Provision may be made for ciclatn or otherwise cooling the liqeutid Tote solution of copper sulphate 95 or other salt of copper and alum may be added an iron salt The length of t Che cell or receptacle containing the solution throughi which the light passes has a very considerable effect on the efficiency of the 100 screen I have found that the addition of an iron salt considerably improves the elficiency of the screen and the blue greentint resulting may be neutralised by the addition of some fadeless acid proof dye ios or staiu hicb would correct the colour.

4 281,066 Or this neutralization of the tinting of the light from colour in the liquid may be effected by providing tinted glazed panels for the enclosing walls of the cell instead -5 of panels of clear glass; or if the cell be made with clear glass panels colour screens may be detachably fitted in the path of the light beam in order to correct and neutralise the tint imparted by the liquid in the cell.

The addition of a rose-coloured cobalt salt to the solution of salts referred to while reducing the colour oi the solution to a minimum at the same time considerably increases the heat resistant value of the screen.

The solution, which has Ibeen found to give thae inost satisfactory results in prac_tice as regards heat absorption is prepared as follows I fi-rst make up a 10 per cent -solution of alum, preferably potassium alum, to which is added 3 per cent, of acid, preferably sulphuric acid, to prevent precipitation of basic salts in :25 the solution A second solution is also prepared containing about 9 3 per cent.

copper sulphate crystals, 6 2 per cent ferric a'uim crystal s, 2 8 per cent cobalt sulphate crystals and 20 per cent nitric acid This second solution is boiled for about five minutes and allowed to cool.

The first and second solutions are then added together, the amount of the second solution used varying accordingy to the, intens-ity of the heat to be resisted.

The solution reduces in only a slight degree the light passing through the cell and where the light beam, as in the case of a cinematograph projector, emanates "-4 o from an electric, arc, the reduction of light may be corrected by using a slightly increased amperage The cell containing the liquid may be mounted in any suitabemanner say on asiging'bakto otherwise between the condenser and gate " through which the film taes or in projectors 'Of the mirror arc, type, the cell would be disposed between the arc and the mirror in which arrangement the - lihttraverses the cell twice in opposite directions and the length of the cell may consequently be reduced by half The longitudinal depth of the cell in the first case may be varied as desired, but a cell from five to seven inches long has been f Quind quite sufficient for all practical purposes The cell is provided with a filling nozzle in the cylindrical wall and such nozzle may be arranged to allow for expansion due to the heat absorbed by the solution By mounting the cell -upon a swinging arm or bracket it may be quickly moved into or out 'of position in order to give facility to the operator for threiading his films.

As applied to the ordinary shop window Or a sky light the cell would take the form of two sheets of glass spaced apart say a quarter or half inch and sealed round their peripheries, the cavity' Ibetween being lilled with a solution prepared as described, the resulting cellbeing.

enclosed in the window frame, or the 'el" may be built ulp in place in the window frame and rendered fluid tight round its periphery.

l Having now particularly described and_ ascertained the nature of my said inven-tion and in what manner the same is to be performed, I declare that what 1 80