Improvements in Apparatus for Coating Photographic Dry Plates and other Plane Surfaces with an Emulsion or Viscous Liquid.
Year: 1889

page_text: Date of Application, 19th July, 1889
Complete Specification Left, 21st Apr., 1890-Accepted. 14th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Coating Photographic Dry Plates
and other Plane Surfaces with an Emulsion or Viscous Liquid.
I, JOHN HENRY SMITH, Ph. 1)., Photographic Chemist, of 9 Merkur Strasse
Hottingen, Zurich, in the Republic of Switzerland, do hereby declare the nature of
this invention to be as follows:-
My invention for Improvements in apparatus for coating photographic dry plates
and other plane surfaces with an emulsion or viscous liquid has for its objects to deliver
the liquid at a uniform rate, to vary the rate of delivery of the liquid according to the
size of the surface to be coated or to the desired thickness of the coat, to distribute
the liquid in a regular stream of the width of the surface to be coated, to construct
the surface down which the.liquid flows on to the surface to be coated so that it readily
adjusts itself to the different thicknesses of the articles whose surfaces are to be coated,
and to provide means for traversing the surfaces to be coated at a regular speed.
and in a horizontal plane past the coating apparatus until the liquid has set and for
cooling the plates in order to set the coating liquid.
The liquid is delivered at a regular rate from a holder placed at a suitable height
above an overflow trough by means of one or more bent tubes or syphons into the
trough. The delivery orifices of the tubes are arranged in a horizontal plane
immediately above the trough. The holder is made broad and shallow and is raised
to such a height that the differences in the level of the liquid in the holder do not
materially affect the pressure and consequently the regularity of the flow. Where
greater accuracy is desired these differences in level are compensated for by making
the delivery tubes partially or wholly of india rubber and altering the height of the
holder; or preferably by employing a closed bottle provided with a delivery or syphon
tube and an air tube extending into the bottle to near its bottom so that the liquid is
delivered under a constant head equal to the vertical distance between the lower end
of the air tube and the exit orifice of the delivery tube.
The rate of delivery of the liquid is varied by means of a graduated tap in each
of the delivery tubes or by altering the height of the holder in relation to the exit
orifices of the delivery tubes or by adjusting the air tube of the closed bottle or by a
combination of these methods, or the ends of the delivery tubes are drawn out and the
quantity of liquid which each nozzle delivers per unit of time when the holder is
fixed at the height indicated is marked upon a fixed vertical scale at convenient
distances apart. The holder is raised and lowered by means of a rack and pinion or
other equivalent mechanical arrangement and its height regulated according to the
desired delivery of the liquid. The flow of liquid is stopped by means of a tap or
clip applied to the delivery tube or tubes.
The delivery trough by means of which the liquid is delivered in a uniform stream
of the width of the surface to be coated is provided with an overflow lip and is divided
by a partition extending nearly to the bottom into two divisions. The liquid flows
from the holder into one division and underneath the partition into the other or second
division where it assumes a perfectly level surface. The liquid is painted by means
of a small brush over that portion of the lip which is immediately above the plate to
be coated and overflows only over that painted portion and falls upon the plate in a
uniform stream. The form of the trough can of course be varied but in order to
obtain a uniform distribution of liquid, the lip over and down which it flows must be
formed of surfaces including obtuse angles only. Where the liquid overflows over a
horizontal surface instead of over an edge a better overflow is obtained and this form
possesses the additional advantage that the trough can he very accurately adjusted and
levelled. The partition of the overflow trough runs in grooves and can be removed

page_text: in order to clean the trough. The trough is fixed to the coating table and levelled by
means of screws.
In order to adjust the surface down which the liquid flows to the different thick-
nesses of the articles whose surfaces are to be coated, the liquid is arranged to flow
over a curved movable piece hinged to the trough at some distance back in the
direction in which the surfaces move. The curved piece may rest directly upon the
surfaces or be separated therefrom by short wires and is of any suitable shape
containing only obtuse angles. It is so constructed that in its vertical motion it
remains in casy contact with the front edge of the trough throughout its whole length
and is bent or curved backwards at the bottom. Its back portion is only slightly
inclined to the horizontal in order that when a thicker plate succeeds a thinner one,
the upward motion of the piece is very slow. Where large plates have to be coated it
is with advantage made jointed at one or more points.
The surfaces to be coated are traversed past the coating apparatus and the liquid
afterward set by supporting them in a long trough upon drums or rollers floating on
water or other liquid in the trough and free to rise and fall and to rotate, but all
motion in the direction of traverse of the plates is prevented. The drums or rollers
are covered with cloth or felt to absorb the cold liquid in the trough and apply it to
the backs of the articles whose surfaces are being coated; or the articles may lie upon
a traversing and stretched endless band the underneath portion of which is either
immersed in the cold liquid or passes underneath the trough containing the liquid;
and the upper portion of which is supported at a constant level and kept constantly wet
by means of the rotating drums or rollers already referred to. It will be evident that
this arrangement will serve the double purpose of a levelling table and a cooling
apparatus.
Dated this 19th day of Jul 1880
WHEATLEY & MACKENZIE,
156, Strand, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Coating Photographic Dry Plates
and other Plane Surfaces with an Emulsion or Viscous Liquid.
I JOHN HENRY SMITH, Ph. D., Manufacturing Chemist, of Hottingen, Zurich, in
the Republic of Switzerland do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
My invention for Improvements in apparatus for coating photographic dry plates
and other plane surfaces with an emulsion or viscous liquid has for its objects to
deliver the liquid at a uniform rate, to vary the rate of delivery of the liquid according
to the size of the surface to be coated or to the desired thickness of the coat, to dis-
tribute the liquid in a regular stream of the width of the surface to be conted to con-
struct the surface down which the liquid flows on to the surface to be coated so that
it readily adjusts itself to the different thicknesses of the articles whose surfaces are
to be coated, and to provide means for traversing the surfaces to be coated at a
regular speed and in a horizontal plane past the coating apparatus until the liquid
has set, and for cooling the plates in order to set the coating liquid.
The liquid is delivered at a regular rate from a holder placed at a suitable height
above an overflow trough by means of one or more bent tubes or syphons into the
trough. The delivery orifices of the tubes are arranged in a horizontal plane imme
diately above the trough. The holder is made broad and shallow and is raised to
such a height that the differences in the level of the liquid in the holder do not
materially affect the pressure and consequently the regularity of the flow. Where
greater accuracy is desired these differences in level are compensated for by making
the delivery tubes partially or wholly of india rubber and altering the height of the
holder or preferably by employing a closed bottle provided with a delivery or

page_text: syphon tube and an air tube extending into the bottle to near its bottom so that the
liquid is delivered under a constant head equal to the vertical distance between the
lower end of the air tube and the exit orifice of the delivery tube.
The rate of delivery of the liquid is varied by means of a graduated tap in each of
the delivery tubes or by altering the height of the holder in relation to the exit orifices
of the delivery tubes, or by adjusting the air tube of the closed bottle, or by a com-
bination of these methods; or the ends of the delivery tubes are drawn out and the
quantity of liquid, which each nozzle delivers per unit of time when the holder is fixed
at the height indicated, is marked upon a fixed vertical scale at convenient distances
apart. The holder is raised and lowered by means of a rack and pinion or other
equivalent mechanical arrangement and its height regulated according to the desired
delivery of the liquid. The flow of liquid is stopped by means of a tap or clip applied
to the delivery tube or tubes.
The delivery trough, by means of which the liquid is delivered in a uniform stream
of the width of the surface to be coated, is provided with an overflow lip and is
divided by a partition extending nearly to the bottom into two divisions. The liquid
flows from the holder into one division and underneath the partition into the other or
second division where it assumes a perfectly level surface.
The liquid is painted by means of a small brush over that portion of the lip which
is immediately above the plate to be coated and overflows only over that painted
portion and falls upon the plate in a uniform stream. The form of the trough can of
course be varied but in order to obtain a uniform distribution of liquid, the lip over
and down which it flows must be formed of surfaces including obtuse angles only.
Where the liquid overflows over a horizontal surface instead of over an edge a better
overflow is obtained and this form possesses the additional advantage that the trough
can be very accurately adjusted and levelled.
The partition of the overflow trough runs in grooves and can be removed in order
to clean the trough. The trongh is fixed to the coating table and levelled by means
of screws.
In order to adjust the surface down which the liquid flows to the different thick-
nesses of the articles whose surfaces are to be coated, the liquid is arranged to flow
over a, curved moveable piece hinged to the trough at some distance back in the
direction in which the surfaces move. The curved piece may rest directly upon the
surfaces or be separated therefrom by short wires and is of any suitable shape con-
taining only obtuse angles. It is so constructed that in its vertical motion it remains
in easy contact with the front edge of the trough throughout its whole length and is
bent or curved backwards at the bottom. Its back portion is only slightly inclined
to the horizontal in order that when a thicker plate succeeds a thinner one, the
upward motion of the piece is very slow. Where large plates have to be coated it is
with advantage made jointed at one or more points.
The surfaces to be coated are traversed past the coating apparatus and the liquid
afterwards set by supporting them in a long trough upon drums or rollers floating
upon water or other liquid in the trough and free to rotate, but all motion in the
direction of traverse of the plates is prevented. The drums or rollers are covered
with cloth or felt to absorb the cold liquid in the trough and apply it to the backs of
the articles whose surfaces are being coated; or the articles may lie upon a traversing
and stretched endless band the underneath portion of which is either immersed in the
cold liquid or passes underneath the trough containing the liquid; and the upper
portion of which is supported at a constant level and kept constantly wet by means
of the rotating drums or rollers already referred to. It will be evident that this
arrangement will serve the double purpose of a levelling table and a cooling
apparatus.
In the accompanying three sheets of illustrative drawings
Fig. 1 is an elevation of a trough for containing the emulsion or viscous liquid
for coating photographic dry plates, constructed-according to my invention, and

page_text: Fig. 4 is a plan, the trough being supposed removed, and
Figs. 5 and 6 are similar views to fig. 3, shewing different arrangements of the
overflow lip, of the same.
Fig. 7 is a longitudinal section of a complete apparatus for coating photographic
dry plates constructed according to my invention, and
.
Fig. 8 is a transverse section and
Figs. 9 and 10 are cross sections, of the same.
Fig. 11 is a side elevation of an arrangement for feeding the plates and for
separating them after they have been coated.
The emulsion or liquid is contained in a vessel 1 fixed above the trough and is
delivered by a flexible pipe provided with nozzles 2 into the trough which is divided,
by the removable partitions 3 sliding in grooves 4 in the sides of the trough, into two
compartments 5, 6 communicating at the bottom through the narrow slit 7. The
quantity of emulsion delivered is regulated by means of the size of the orificies of the
nozzles employed. The tap 8 serves to completely shut off the supply of emulsion.
The trough 5, 6 is provided with an overflow lip 9 which is shown as a horizontal
surface having obtuse angles on either side in fig. 6 and as an obtuse angle in fig. 5.
It will be readily understood that these overflow lips can be easily adjusted to a
horizontal position which it is very difficult to do with curved overflow lips. The
overflow trough is fixed to the frame 10 supported from the coating table by means of
the levelling screws 11 by means of which the overflow lip can be accurately adjusted
to a horizontal position.
The lip 9 being painted with emulsion as above described, the emulsion overflows
only over the painted portion and on to a moveable piece 12 which is secured to
rods 13 extending backwards under the trough and mounted on a shaft 14 supported
in suitable bearings. The movable piece 12 is curved to any suitable shape containing
only obtuse angles and rests directly upon the surfaces 15 to be coated. It will be
seen that when coating plates of different thicknesses, the piece 12 will rise or fall
according as the plate to be coated is thicker or thinner than the plate just coated. Its
back portion is only slightly inclined to the horizontal so that when plates of different
thicknesses succeed one another its vertical motion is slow. That part 16 of the
piece 12 in contact with the forward edge of the lip of the overflow trough is curved
having a radius equal to its distance from the shaft 14 so that it remains in easy
contact with the said forward edge throughout its whole length. The piece 12 is
shown constructed in two parts.
The plates 15 to be coated are placed on a shelf 17 behind the vessel 1 and are fed
by hand on to travelling belts 18 passing over rollers 19, 20, the roller 19 being
driven from the hand wheel 21 through the worm gearing 22. From the belts 18 the
plates pass on to cylinders 23 contained in a trough 24 situated immediately below
the movable piece 12 and serving to catch any emulsion that may drop between the
plates. The pivots of the cylinders 23 are let into perpendicular slots in the sides of
the trough 24. The cylinders are hollow and are provided with teeth which form a
support for the plates 15 as they are fed along. The trough 24 is preferably filled
with water until the cylinders just begin to float when they will rotate easily on the
passage of the plates. Instead of having teeth on the cylinders a series of discs may
be supported on them at intervals as shown in Fig. S.
The plates 15 then pass on to the web 25 of some good absorbent material kept
taut between the two rollers 26, 27, the roller 26 being driven from a pulley 28 on
the same axis as the roller 19 by means of a belt 29 and gearing 30. The web 25 is
also supported by the intermediate rollers 31 which serve to keep it perfectly
horizontal. The rollers 26, 27 and 31 are supported in bearings in a trough 32
containing cold water which is thus applied by the web 25 to the backs of the coated
plates to set the emulsion. The level of the water may be above that of the axes of
the rollers. According to the weight of the rollers and the height of the water in
the trough, an upper or a lower support may be dispensed with. The best result is
obtained when the rollers are so constructed and the water so adjusted that the rollers

page_text: are just about the point of floating. The rollers are also preferably covered with felt
which serves to supply the cold liquid in the trough to the web 25.
Fig. 11 shows a modified arrangement by means of which the coated plates are
separated. In this arrangement the shaft 33 is driven from the hand wheel 34 through
the toothed wheels 35 36 and bevel gearing 37. On the shaft 33 are fixed the
worms 38 and the double worms 39, 40, the pitch of the worms 39 and 38 being equal
and slightly greater than that of the worms 40. The worm 38 drives by means of a
worm wheel and roller the endless belt 41. Each double worin 39, 40 can be adjusted
on the shaft 33 by means of the screws 18 so that either part can be made to gear
with a worm wheel 42 driving a roller supporting the plates and serving to feed them
onward. By means of these adjustable double worms, an increased speed can be
given to any roller, according to the size of the plates being coated, and to all the
following ones. Any or all of the rollers may be covered with some good absorbent
material.
The endless bands on to which the plates 15 are fed by hand is driven from the
shaft 33 through the toothed wheels 43, 44, worm 45, worm wheel 46, and roller 47,
at the same speed as the slower rollers supporting the coated plates.
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 I
claim is :-
1. In apparatus for coating photographic dry plates and other plane surfaces with
an emulsion or viscous liquid, a trough divided by means of a removable partition
into two compartments communicating at the bottom underneath the said partition,
one compartment serving to receive a regular stream of emulsion and the other being
provided with an overflow lip comprising a flat horizontal surface or of two flat
surfaces meeting at an obtuse angle substantially as described.
2. In apparatus for coating photographic dry plates and other plane surfaces with
an emulsion or viscous liquid, applying to the surface over which the emulsion flows
to the plates to be coated, a movable curved piece substantially as described and for
the purpose specified.
3. In apparatus for coating photographic dry plates and other plane surfaces with
an emulsion or viscous liquid, the arrangement for feeding on and setting the coated
plates consisting of rollers supported in a trough containing water and covered with
some good absorbing material so as to apply the cold water to the backs of the coated
plates, substantially as described.
4. In apparatus for coating photographic dry plates and other plane surfaces with
an emulsion or viscous liquid, the arrangement by means of which an increased speed
can be given to a plate as soon as it is coated whatever its size consisting of a series
of rollers supporting the said plates after they are coated and each of which is driven
by either part of a double worm, the two parts of each worm corresponding to a
quicker or slower speed substantially as described.
5. Apparatus for coating photographic dry plates and other plane surfaces with an
emulsion or viscous liquid substantially as described with reference to the drawings."
1341 this 10th day of Anvil 1800
WHEATLEY & MACKENZIE,
40, Chancery Lane, W.C., Agents.