Improvements in Apparatus employed in the Manufacture of White Lead.
Year: 1893

page_text: Date of Application, 11th Feb., 1893
Complete Specification Left, 13th Nov., 1893-Accepted, 16th Dec., 1898
PROVISIONAL SPECIFICATION.
Improvements in Apparatus employed in the Manufacture of
White Lead.
1 JACOB VICKERS WALTON, of Bollihope Lead Works near Darlington in the
County of Durham, Lead Manufacturer do hereby declare the nature of this
invention to be as follows:-
My invention has for its object to provide mechanical appliances for use in the
manufacture of white lead by the Dutch method whereby the handling of the white
lead in course of manufacture is entirely superseded and the injurious effects on
the health of the operatives incidental to that process as now carried on are
obviated.
The invention has also for object to provide means of regulating the ventilation.
and temperature of the stack in which the conversion of blue lead into carbonate
is effected, whereby to bring the process of conversion completely under control
and increase the yield of carbonate.
The process of making white lead may be divided into four stages, to all of
which my invention applies in a greater or less degree, but particularly to the first,
third, and fourth stage, viz.-
1. Loading and unloading the white lead stack.
2. Grinding and washing the white lead.
3. Drying the washed white lead in stoves.
4. Packing the dried white lead in casks.
For the purpose of carrying out the first stage of the process, the stack is n
structure within which tiers of girders of I-section are fixed in such manner that
the lower flanges of the girders of each tier are adapted to form railways on which
wheeled trays introduced at the open side of the stack may be run into position
into the stack, the spaces intervening between the tiers being reserved for the beds
of tan laid upon boards resting on the girders. The trays are of cellular
construction and are adapted to hold a large number of pots charged with blue
lead and acid, and to oppose the least possible obstruction to the transmission of
the heat of the beds to the pots. In the operation of building up the stack with
beds and tiers of pots alternately, I employ wagons to bring the loaded trays from
the casting room to the stack, running on a railway passing in front of the stack
and I provide a set of receiving tables supported on wheels running on another
line of rails, said tables corresponding respectively in height to the several tiers of
girders of the stack and being either separate structures or a step-like series of
tables in a single structure so that in either case a table corresponding in height to
the particular tier to be loaded, may be brought opposite any pair of girders of
that tier. Upon these tables, rails are fixed which match with those of the girders,
so that a tray raised by a crane from the wagon which brought it to the stack and
deposited on the rails of the table may be quickly run into position in the stack.
Doors are provided for closing the apertures at which the trays are introduced.
In loading the stack, the tiers are filled with trays in succession and in unloading,
the same appliances are employed. The tan to form the beds is introduced, in
barrow-loads, at apertures in the opposite or back wall of the stack which apertures,
as each bed is completed, are closed by suitable doore, the operation of laying the
floor boards for and preparing the beds being performed in succession from the
lowest upwards and inversely in unloading the stack. In these doors or in other
suitable positions, apertures closed by dampers are provided whereby the admission
and circulation of the air from below upwards through the whole series of tiers

page_text: may be regulated and hand-holes or sight-holes are provided in each tier whereat
thermometers may be introduced into the air current or be visible from without to
enable the temperature and working condition of all parts of the stack to be
ascertained without interfering with the circulation of the air.
For the purpose of preventing the inhalation of the white lead dust by the
operatives in the grinding operation, I provide hoods in connection with an exhaust
fan, the hoods being so situated with respect to the operatives that the air
contaminated with any dust arising in the operation of grinding will be carried
away from the operative and replaced by a pure atmosphere, the dust so carried off
being intercepted and deposited in a closed receiver before the dust-laden air is
discharged by the fan.
After the white lead has been ground and washed in the ordinary way it is
charged into basin-like receptacles which are loaded on to cellular trays or grids
provided with bows or other means whereby they may be slung from above upon
parallel cross-bars supported removably upon pairs of girders fixed in tiers in the
drying stove. The loaded trays are carried in and out of the stove upon wagons
adapted to the heights of the various tiers and running on railways on the floor of
the stove, each wagon being constructed with an elevating platform operated by
screw or other gear whereby the height of the platform may be so adjusted with
regard to that of the tier to be loaded or unloaded that the tray may be brought
into position to allow of the removable cross-bars being inserted or removed. The
operation of loading the shed is performed from the top tier downwards in succession
and that of unloading in the inverse order.
When the drying operation is completed, the trays are removed and run on the
wagons to the packing shed where the trays are removed by a crane and transferred
to a convenient position for packing the white lend into casks. This is performed
by running the tray containing the dry white lead in basins, beneath a hood and in
connection with an exhaust fan, the hood being open only on the side next the
workman. Beneath the hood is a spout leading to the cask to receive the white
lead and into which the contents of the basins are discharged by means of tongs
whereby the basin is seized and inverted over the spout without the workman
approaching so close thereto as to be liable to inhale particles of white lead, any
dust arising being carried away by the exhaust current of air and intercepted and
deposited as above described.
Dated February 11th 1000
COMPLETE SPECIFICATION.
Improvements in Apparatus employed in the Manufacture of
White Lead.
I, JACOB VICKERS WALTON of Bollihope Lead Works, near Darlington, in the
County of Durham, Lead Manufacturer, 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 relates to the manufacture of white lead by the Dutch method and
has for its object to facilitate the loading and unloading of the white lead stack, to
provide means of regulating the ventilation and temperature of the stack, and to
provide means whereby the handling of the white lead and the consequent liability
of the operatives inhaling white lead dust, in the operations of drying the white
lead, are obviated.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein Figure 1 is a longitudinal section (partly broken ont)

page_text: Figure 2 a part transverse section, part elevation, and Figure 3 a horizontal section
of the stack illustrating the construction and, in part, the special means employed
in loading and unloading the same.
Figures 4 and 5 are front and side elevations of the truck-supporting brackets,
drawn to a larger scale and shewing in section the front wall and one of the
ventilating passages therein.
Figures 6, 7, 8, are side and end elevations and plan of the loading and
unloading truck, and Figures 9 and 10 a plan and longitudinal section of the
charging crates, for supporting the pots in the stack shewn in Figures 1, 2, 3.
Figures 11 and 12 are respectively a longitudinal section and half sectional end
elevation of the drying stove.
Referring to Figures 1 to 3 :-The stack A is a brickwork structure having tiers
of parallel girders B extending between, and supported by, the front and rear
walls a a¹ and also by intermediate columns if required. The girders are preferably
made of teak and they are of 1-section. They are suitably spaced to receive
between each two adjacent girders cellular frames or crates (carrying pots con-
taining acid and blue lead) introduced through apertures C in the front wall, said
apertures extending the whole width between the webs of the girders and being
closed by hinged flaps when the stack is charged. The crates rest on the
flanges of the girders whose length from front to back is sufficient to accom-
modate a number of crates introduced in succession, whilst the depth of the
girders and crates is such that the latter and their contained pots do not rise above
the webs of the girders. In the spaces E the beds of tan are laid upon loose floor
boards e resting on each tier of girders.
The crates I, Figures 9 and 10, are introduced through the apertures C and
deposited upon the flanges b of the girders, by means of the truck represented in
Figures 6, 7, 8, whose wheels also run on the flanges of the girders. The truck
before entering the aperture C rests on a platform F having rails f which match
with the girder flanges b, the platform being temporarily supported upon a pair of
brackets & corresponding to the pair of girders to be loaded, there being as many
brackets as there are girders, the brackets being pivoted to the front wall of the
stack so that they may be swung aside or turned outwards as required.
Figures 9 and 10 shew one of the rectangular cellular frames or crates I in
which the pots i charged with acid and lead are placed, the pots which rest on
ledges being round whilst the cells are square and open at bottom to permit the
transmission of the heat of the beds to the pots.
The loading and unloading truck, Figures 6, 7, and 8, is a wheeled frame J
provided with a pair of rearwardly-projecting arms and with two sets of worm
and screw gear situated at the front and rear ends of the truck, the worms j¹
being on a common shaft operated by a crank handle and the screws being
connected to cross-bars to which the armsj are fixed, the whole forming a lifting
and lowering cradle which is guided by vertical posts working in guide sockets
Upon the arms, when raised to the dotted position shewn in Figure 6, the crate I
is carried into its destined position, the arms being then lowered the crate is
deposited on the flanges of the girders.
b
In loading the stack the lowermost bed of tan is first laid on its floor e and then
crates I containing the charged pots are raised by a crane and deposited on the
truck J which has previously been placed on the platform F resting on a pair of
brackets G. The truck J is then run through the aperture Con to the girder
flanges upon which the crate is deposited, the truck returning to the platform to
receive another crate which is introduced in turn, and so on, until the space.between
a pair of girders is full after which the flap D is closed. The platform F, with the
truck J upon it, is then transferred by the crane to another pair of brackets G and
the operation is repeated, and so on, until the tier is filled. The floor boards e are
then laid upon the girders which have been loaded and the next bed of tan having
been spread on them the platform and truck are raised to the next tier above which
is then loaded, and so on.

page_text: The tan is introduced in barrow-loads at a doorway K, the doorway extending
the whole height of the wall a¹ and being closed by two sets of boards & dropped
into grooves at the inside and outside of the doorway as the loading of the
stack proceeds, the space between the two sets of boards being filled with tan.
The circulation of air throughout the stack is provided for by passages L L' in
the front and back walls a a¹, which connect in zig-zag order the spaces E,
regulators M M' in the lowermost and uppermost flaps D permitting the ingress
and egress of air. Glazed sight-holes are provided in the wall a¹ for the
inspection of thermometers placed in the air-passages L₁ so that the temperature
of the air may be ascertained at any part of the stack. To promote the corrosion
of the lead in the lower tier the air may be heated and supplied to the stack by
flues M2, shewn in dotted lines, built in the front wall a (instead of by the
regulators M in the lowermost flaps D).
After the conversion of the blue lead into carbonate of lead the crates are
removed by the truck J, Figures 6, 7, and 8, and lowered by the crane.
The white lead is removed from the pots i and transferred to the grinding mill.
The ground white lead is filled into earthenware or copper pans t secured in
trays T and transported to the drying stove illustrated in Figures 11 and 12.
This is a shed having pairs of supporting ledges u arranged in superposed tiers at
proper distances apart to receive the trays T. These ledges may be fixed to the
side walls U of the shed and to intermediate posts U¹, there being generally two
or more series of tiers of ledges arranged side by side. Beneath each series is a
tramway upon which run wagons V for depositing the trays on, or removing them
from, the ledges u. For this purpose each wagon V is provided with an elevating
table v capable of being raised and lowered by a central screw v¹ whereby several
tiers of ledges u are brought within range of one wagon, several wagons of different
heights being used. The loading of the drying stove is commenced by first raising
the elevating table vso that the tray T is just above the level of the uppermost
pair of ledges u, then running the wagon into the stove, lowering the table v so
that the tray rests on the ledges u, and then running the empty wagon out to
receive another tray and so on. The operations are then repeated for placing
trays on the ledges next below, and so on in succession, another wagon of less
height being used for the lowermost tiers, a turnplate being provided opposite each
entrance to the stove and sidings for the wagons not in use.
The stove is divided
into two stories similarly arranged and worked, the trays being raised by a crane
to the wagons running on the tramways of the upper storey.
When the stove is
filled, the doors are closed and heat applied in the usual way.
When the drying
operation is completed, the trays are removed by running the wagons under them
and lifting them off the ledges u beginning with the lowermost tiers. The trays T
are then transported to the packing shed.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
Apparatus for the manufacture of white lead by the Dutch method, com-
prising:
:-
1. A stack having tiers of parallel flanged girders, apertures in the front wall
between each pair of girders, doors closing said apertures, floors resting on the
girders to receive tan beds and dividing the spaces between superposed tiers of
girders from one another, air passages connecting said spaces in zig-zag order, as
specified.
2. In combination with a stack constructed as herein described, cellular pot-
holding frames or crates adapted to be introduced between the girders of the
stack and to rest upon the flanges thereof, as specified.
3. In combination with a stack constructed as specified, brackets pivoted to the
front wall of the stack, a platform supported by said brackets and having rails
watching the flanges of the girders, and a wagon adapted to run upon said rails

page_text: and flanges to carry pot-holding cellular frames or crates into or out of position on
the flanges of the girders, substantially as specified.
4. In combination with a stack constructed as described and provided with
extension platform supporting brackets, a wagon adapted to run on the rails of the
extension platform and on the flanges of the stack girders, said wagon being provided
with a rearwardly-projecting crate-carrying cradle adapted to be raised and lowered
by worm-operated screw mechanism for introducing and depositing the crates in the
stack or removing the same therefrom, substantially as specified.
5. A white lead drying stove provided with pairs of rails in superposed tiers
adapted to receive pan-holding trays upon them, in combination with wagons
provided with screw-operated raising and lowering gear adapted to run between
the pairs of rails in the stove and to deposit the pan-holding trays thereon or
remove the same therefrom, substantially as specified.
Dated this 13th doy of November 1802
J. V. WALTON,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.