Improvements in Washing and Drying Galvanized Sheets, and in Means or Appliances for Use therein.
Year: 1893

page_text: Date of Application, 9th June, 1893
Complete Specification Left, 9th Mar., 1894-Accepted, 2nd June, 1894
PROVISIONAL SPECIFICATION.
Improvements in Washing and Drying Galvanized Sheets, and in
Means or Appliances for Use therein.
We, DAVIES BROTHERS AND COMPANY, LIMITED, of the Crown Works,
Wolverhampton in the County of Stafford, Galvanizers, and STEPHEN THORPE
THOMAS, Works Manager to the said Company, do hereby declare the nature of
this invention to be as follows:-
-
In the ordinary process of washing and drying a fluxed galvanized sheet the spelter
or coating metal is first allowed to set or crystallise over the entire surface thereof.
The sheet is then dipped first into a bath of hot water and next into a bath of cold water,
and is then placed on edge and allowed to drain. It is then rubbed over by hand with
sawdust or sharps, and any adhering sawdust or sharps is afterwards brushed off; and
the sheet is finally placed in a drying oven to dry the surface and prevent oxidation.
As the sheet is withdrawn from the galvanizing bath the flux thereon continues to
boil, owing to the temperature of the sheet, and rapidly dries up and burns, and it
is desirable therefore to dissolve and wash such flux away before it has become
dried; but when, as in the ordinary method, the sheet is allowed to remain before
washing until the whole surface has set or crystallised, the flux on the portion
thereof which was first withdrawn from the bath frequently dries up and burns
before the whole of the surface has become set. The burnt flux leaves permanent
marks upon the surface of the sheet. Moreover, the sheet requires time to drain
after removal from the cold water bath, and its surface is thus liable to oxidise and
become consequently dull, dead or white in appearance. The necessity for finally
drying the sheets in a stove is occasioned by the sawdust or sharps employed in
rubbing the surfaces of the sheets after washing becoming damp and not thoroughly
drying the sheets.
Now, according to this invention, the sheets, as they pass out through the flux
and are delivered from the galvanizing bath, are caught between a pair of feeding
rolls of which the operative surfaces consist of a number of pegs or projections
terminating outwards in ends of small area so as not to injure the coating of the
sheets. Each sheet is fed, by means of these rolls, between a pair of brushes
which revolve rapidly the one above and the other below the sheet in position so as
to not quite touch the surfaces thereof. These brushes are contained within a
suitable casing or chamber. Water is supplied through a perforated tube at the
top of the case on to the upper brush, and water is projected sideways from a
perforated tube against the lower brush. The brushes as they revolve throw the
water in a fine spray, and with considerable force, against the upper and lower
surface of the sheet. A sheet as it passes forwards between the washing brushes
enters between a second pair of brushes revolving rapidly the one above and the
other below it in position to rub against it as they revolve. These brushes are
contained within a suitable case or chamber which is fitted with a hopper at the top
through which sawdust (sharps or other material suitable for the purpose) is fed;
and, in starting to work, a supply of sawdust is placed also in the bottom of the
case. As these brushes revolve, the sawdust is projected in a continuous shower
against the surfaces of the sheet, and is also rubbed thereagainst by the action of
the brushes. The surfaces are thus thoroughly dried, and the surplus sawdust is
drawn away from the bottom of the case, and fresh sawdust supplied from time to
time to the hopper at the top thereof. The sheet passes from the sawdust brushes
between another pair of brushes by which any sawdust adhering thereto is brushed

page_text: away and the sheet thoroughly cleaned; and the sheet is drawn from between such
brushes by a pair of rolls. The feeding rolls propel each sheet forward between
the washing and drying brushes and the cleaning brushes, until it is caught
between the drawing rolls aforesaid.
The whole apparatus for washing and drying the sheets, and preferably also the
brushes for finally cleaning them, are carried by a frame which is mounted in suitable
slides along which it can be traversed from and towards the bath by means of
screws or racks and pinions, or in other convenient manner; and the apparatus is
so adjusted in relation to the bath, having regard to the temperature thereof, and
to the gauge of sheets under treatment, that the sheets commence to enter between
the washing brushes almost immediately the coating metal has set or cystallised on
the forward ends, the speed of traverse corresponding with the rate at which the
coating metal continues to set or crystallise along the surface of the sheet.
By the employment of this invention, every portion of the surface of a sheet is
washed almost immediately after the coating metal has set or crystallised, and thus
the flux is dissolved and washed off before it can become burnt.
Any other
impurities are, of course, washed away also. A small amount of water only is
required, and the dirty water passes away at once from the bottom of the washing
chamber, and is not used over again. The sheets retain their heat to a considerable
degree while passing between the drying brushes, and pass out from the drying
casing or chamber in a dry condition, so that there is no need to place them
subsequently in a drying stove; and the rapidity of the whole operation, which is
entirely automatic, does not allow time for oxidation. A considerable saving in
labour is thus effected, and a better and more uniform appearance of the surface of
the sheet ensured.
The apparatus above described is intended, more especially, for use with
apparatus which delivers the sheets automatically from the bath into the feed rolls
first above described, and is specially suitable for employment with the delivery
rolls, by which sheets are delivered from the galvanizing bath, described in Patent
Specification No. 18066 of 1890, the sheets being delivered first on to a drum,
having parts of small area projecting therefrom, as therein described, and passing
from the drum direct into the feed rolls.
The sheets as they leave the drawing or feeding rolls, by which they are drawn
out from between the last pair of brushes, may pass direct on to a carrier system
such as described in the said Patent Specification No. 18066 of 1890, and be thus
conveyed where required.
Dated this 8th day of June 1893.
STEPHEN WATKINS,
Wolverhampton, Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Washing and Drying Galvanized Sheets, and in
Means or Appliances for Use therein.
We, DAVIES BROTHERS AND COMPANY, LIMITED, of the Crown Works,
Wolverhampton in the County of Stafford, Galvanizers, and STEPHEN THORPE
THOMAS, Works Manager to the said Company, 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:-
In the ordinary process of washing and drying a fluxed galvanized sheet the
spelter or coating metal is first allowed to set or crystallise over the entire surface
thereof. The sheet is then dipped first into a bath of hot water and next into a
bath of cold water, and is then placed on edge and allowed to drain. It is then
rubbed over by hand with sawdust or sharps, and any adhering sawdust or sharps
is afterwards brushed off by hand; and the sheet is finally placed in a drying oven

page_text: to dry the surface and prevent oxidation.
As the sheet is withdrawn from the
galvanizing bath the flux thereon continues to boil, owing to the temperature of
the sheet, and rapidly dries up and burns, and it is desirable therefore to dissolve
and wash such flux away before it has become dried; but when, as in the ordinary
method, the sheet is allowed to remain before washing until the whole surface has
set or crystallised, the flux on the portion thereof which was first withdrawn from
the bath frequently dries up and burns before the whole of the surface has become
set. The burnt flux leaves permanent marks upon the surface of the sheet.
Moreover, the sheet requires time to drain after removal from the cold water bath,
and its surface is thus liable to oxidise and become consequently dull, dead or
white in appearance.
The necessity for finally drying the sheets in a stove is
occasioned by the sawdust or sharps employed in rubbing the surfaces of the sheets
after washing becoming damp and not thoroughly drying the sheets.
Now, this invention has for its object to cause every portion of the surface of a
sheet to be washed almost immediately (or as nearly so as may be conveniently
practicable) after the coating metal has set or crystallised, so that the flux may be
dissolved and washed off before it can become burnt, and to cause also any other
impurities to be washed away at the same time, and to ensure, without the use of
a drying stove, that the sheet shall be so rapidly and thoroughly dried as to avoid
any liability of oxidation, and finally to effect also a considerable saving in labour
and ensure a better and more uniform appearance of the surface of the sheet.
The above object is effected, according to this invention, by carrying the sheets,
on their passage from the galvanizing bath, first between washing brushes or
appliances which project the water at a high velocity in the form of a fine spray
against the surfaces of the sheets, and then between drying brushes to which
drying material is supplied, and which dry and clean the sheets, the sheets being
entered between the washing brushes or appliances as soon as may be conveniently
possible after the coating metal on their forward ends has set or crystallised, and
passed between such brushes or appliances at the speed at which the setting of the
metal takes place along their surfaces.
In order that the invention may be clearly understood, we will proceed to
describe a practical application of it with reference to the accompanying drawings,
of which
Figure 1 is a longitudinal section through the apparatus, constructed according
to this invention, for use in washing and drying galvanized sheets in the manner of
the invention.
Figure 2 is a longitudinal section through apparatus for finally cleaning, the
sheets after they have been washed and dried in the apparatus illustrated by
Figure 1.
Figure 3 is a plan of the apparatus shewn by Figure 1.
Figure 4 is a plan of the apparatus shewn by Figure 2. And
Figure 5 is an elevation of the apparatus for drying the sheets, as seen viewed in
the direction of the arrow a, Figure 1.
The apparatus illustrated by Figures 2 and 4 is shewn on separate sheets from
the apparatus illustrated by Figures 1 and 2, simply for convenience of illustration.
The former apparatus is really connected with the latter, and the parts through
which the connection is made are shewn, in the several figures, as if broken off.
A is the delivery side or end of the galvanizing bath. ff are a pair of rolls of
which the operative surfaces consist of a number of projections terminating
outwards in ends of small area so as not to injure the coating of the sheets.
These rolls correspond to the rolls ff described in Patent Specification No. 18066
of 1890 (except that the number of projections is greatly increased, and the
projections are shaped as small pyramids with flattened tops for convenience in
forming them in the same pieces of metal as the rolls), and are similarly placed in
relation to the metal in the bath, and are positively driven as is the case with such
rolls. For convenience of manufacture, the rolls are made in a number of short
lengths which are put on the spindles and dowelled together. These rolls. draw.

page_text: the sheets out from the molten coating metal, and as they do so the sheets fall on
to a drum C having parts of small area projecting therefrom. This drum
corresponds to the drum C described in the aforesaid Patent Specification, and is
positively driven in a direction to convey the sheets away from the bath. A
drum C, like the drum C, is carried in position some distance from the drum C ;
and endless chains form with the drums a short carrier system similar to the
carrier system described in the said former Specification. The sheets are carried
forward in turn by this carrier system and fed thereby between a pair of brushes bb
which revolve rapidly, in the directions, respectively, indicated by the arrows
adjacent thereto, the one above and the other below the sheet, the ends of the
fibres or bristles composing the brushes being about two inches from the surface of
a sheet as it passes between the brushes so that they do not come in contact with
the sheet. These brushes are contained within a suitable casing or chamber B.
Water, at a boiling temperature, or at as high a temperature as it can conveniently
be obtained, is supplied through a perforated tube c, at the top of the case, on to
the upper brush; and water is projected sideways from a perforated tube d against
the lower brush. The brushes as they revolve throw the water in a fine spray,
and with considerable force, against the upper and lower surfaces of a sheet; and
the dirty water falling to the bottom of the case B, runs away through an outlet
slit, into a trough F from which it passes away through a pipe e to the drain.
The slit k runs the whole length, or approximately so, of the bottom of the case,
and the dirt is thus readily washed out through the slit by the water as it flows
out therethrough. The sheet is guided between top and bottom guides h h through
the case B within which the brushes b b revolve, and as it passes forwards from
between the washing brushes b b it is guided between the top and bottom guides hh
to, and enters between, a pair of feed rolls g g each formed with narrow collars g¹
having plain cylindrical bearing surfaces. The collars are formed narrow so as to
bear on a small width only of the surface of a sheet, and thus minimise the
risk of rolling on to the surface any impurities. The rolls 9 g feed the
sheet forwards between top and bottom guides i i, and between a second
pair of brushes ; j revolving rapidly, in the directions, respectively, indicated
by the arrows adjacent thereto, the one above and the other below it in
position to rub against it as they revolve. The outer ends of the fibres
or bristles of one of these brushes should overlap those of the other brush,
say about an inch, when no sheet is passing between the brushes. These
brushes revolve within a case or chamber D which is provided with a hopper E
at the top. Sawdust (sharps, or other material suitable for the purpose)
is supplied to the hopper E, and passes therefrom into the upper portion of
the case D. As the brushes jj revolve, they throw the sawdust in all directions,
and as a sheet passes through between the brushes the sawdust is projected in a
continuous shower against its surfaces, and is also rubbed thereagainst by the
action of the brushes. The surfaces are thus thoroughly dried and are also cleaned,
and the surplus sawdust falls out through a narrow opening m in the bottom of
the case, and thence down a shoot G into a well H from whence it is elevated, by
elevator chains J J (or an elevator band) carrying elevator buckets J' J', and is
delivered into the hinder end of a shoot K, and runs down such shoot into the
hopper E, so that the sawdust is used over and over again. The forward end of
the shoot K is suspended by a rod n from a bearer o, and the hinder end is fixed
to the lower end of an arm p which is pivoted at its upper end to a support q.
connecting-rod r is pivoted at one end to the arm p, and is engaged at its other
end with a crank-pin s carried by the overhead wheel s' of the elevator; and thus,
once during each revolution of the wheel s', the hinder end of the shoot K is
moved outwards and allows a bucket which has already delivered its contents into
such shoot to pass down clear of the shoot. The special form of elevator described
and illustrated is not, of course, essential, as any convenient arrangement of
elevator may be used; and, if the elevator chains (or band) are carried sufficiently
inclined, it is obvious that the shoot K need not be moved outwards for a bucket
A

page_text: to clear it, as ample clearance may be given for a bucket to clear the shoot after
delivering its contents thereinto.
As the sheets are washed while still in a heated condition, and retain their heat
to a considerable extent as they pass out from the washing chamber B, they
become considerably dried before entering the chamber D; and thus a given
quantity of sawdust may be passed through the chamber D a considerable number
of times before it is too damp to be efficient in drying the sheets; and when it is
required to be changed it can be removed from the well H, and fresh sawdust
supplied thereto.
The sheets are carried forwards from the drying brushes jj along the guides i i
which pass through the chamber D and extend beyond it, and euter between a pair
of feed rolls tt, of which each roll is formed with narrow collars t' which press
against narrow surfaces of the sheets only and thus minimise the risk of rolling
any sawdust adhering to the sheets on to the surfaces thereof; and the sheets are
fed forwards by these rolls along guides u u which curve in an upward direction,
as shewn, and between brushes v revolving rapidly in the directions, respectively,
indicated by the arrows adjacent thereto, which brush away any sawdust adhering
to the surfaces of the sheets and thoroughly clean the surfaces. The sheets are
drawn from between the brushes vv by means of rolls d¹ d' which are similar to
the rolls g and t before described; and as the sheets emerge from the rolls d' they
are deflected by curved guides 61 on to a carrier system having chains c¹, such as
the carrier system described in the said former Specification, by means of which
they are conveyed away.
The brushes vv are shewn by Figure 2 as placed in position to operate against a
sheet whilst the same is in a nearly vertical position, so that any particles of dirt
may readily fall clear of the sheet when separated therefrom by the brushes; but
the brushes may be arranged, if preferred, so that the sheets shall pass between
them horizontally, as in the manner of brushing sheets by means of revolving
brushes described in the said former Specification.
The method of driving the various portions of the apparatus may, of course, be
modified. In the particular apparatus illustrated, the lower of the pair of brushes j
is driven by means of a band passing around a pulley on an overhead shaft (not
shewn in the drawings) and around the pulley e¹ fixed on one end of the brush
spindle. The upper brush j is driven by means of a belt f¹ from a pulley on the
opposite end of the lower brush spindle to that on which the pulley e' is fixed.
The lower brush b is driven by means of a belt s² from the spindle of the lower
brush; and the upper brush 6 is driven by means of a belt from a pulley on the
opposite end of the spindle of the lower brush 6 to that on which the pulley is
fixed which is operated by the belt s³. One of the brushes v is driven by a belt a¹
from a pulley on an overhead shaft, not shewn, which passes around a pulley ³ on
the brush spindle; and the other brush is driven by a belt from the spindle of
its fellow brush. The chains c¹ of the carrier system beyond the rolls d' d' pass
at the inner end of the carrier system, for convenience in the general arrange-
ment, around drums L, M, and N; but of course one drum only may be used at
such end if preferred. The drum N is driven by means of a belt from a pulley on
an overhead shaft, not shewn, which passes around the pulley O fixed on the
spindle of such drum, and thus the carrier chains are operated. The lower roll t
is operated by means of a chain k' from the spindle of the drum N. One of the
rolls d' is operated by means of a chain l from the spindle of the lower roll t;
and the lower roll is operated also by means of a chain m' from the spindle of
the lower roll t. The barrel C¹ of the carrier system adjacent to the galvanizing
bath is operated by means of a belt n' from the spindle of the lower roll 9. The
barrel C is, of course, operated by the carrier chains c². The rolls of each pair
are geared together by a toothed wheel of the one driving a toothed wheel of the
other. The elevator is driven by means of a chain p₁ from the spindle of
the drum N which passes around a wheel on the lower spindle of the
elevator."

page_text: It is not, of course, essential that in some instances belts, and in some instances
chains, should be used for driving one shaft or spindle from another; the drawings
have been made from the machine as fitted up, and as in some cases belts are shewn,
and in others chains are indicated, the description has been made to correspond
therewith.
In order to obtain the fullest advantage in washing the sheets, they should
⚫commence to enter between the washing brushes immediately the coating metal has
set or crystallised on their forward ends, and regard to this should be had in
fixing the distance between the drum C and the washing brushes. Thin sheets
such as No. 26 B. W. G. require, in order that they may be properly coated, to
pass out from the molten coating metal at the rate of about 18 feet per minute,
and the distance from the centre of the brushes to the surface of the molten metal,
measured along the surface of the sheet, should be about four feet. Thicker sheets
should, as is well understood, leave the bath somewhat more slowly. They retain
their heat, however, longer than the thinner sheets, and the coating metal does not
consequently crystallise so quickly. It is found in practice that four to five feet
is a suitable distance from the centre of the washing brushes bb to the centre of
the drying brushes jj, whatever the thickness of the sheets which are being treated.
"The cleaning brushes vv may be placed at any desired distance from the drying
brushes jj. The washing, drying and cleaning brushes may each be conveniently
about 12 inches diameter. The washing brushes may be run at a velocity of
about 260 revolutions per minute, and the drying and cleaning brushes at a
velocity of about 130 revolutions per minute. The operative parts of the brushes
may be of fibre, such as is used for brushes for other purposes, or may be of
bristles.
In order to enable the distance between the washing brushes and the drum C to
be adjusted to suit different conditions of working, and thus ensure in any case
that each portion of the surface of a sheet shall be washed almost immediately the
coating metal thereon has set, and at the same time maintain the relative
positions of the other parts of the apparatus, the pairs of brushes, guide rolls,
drums C, L, M and N, and the elevator, may be carried on slides P fitted to be
capable of being moved longitudinally along fixed V-guides R, through the
medium of screw pins S fitted to turn within lugs u' on the ends of the guides R
and screwed through lugs v¹ on the ends of the slides P, and of being held by such
screw pins in any position into which they have been moved. A hand wheel w¹ is
fixed on each pin S whereby the pin is operated. The slides P and V-guides R
are shewn in transverse section in Figure 5.
By the employment of this invention, every portion of the surface of a sheet
may be washed almost immediately after the coating metal has set or crystallised,
as the sheets pass of course through the brushes at the rate of speed at which they
leave the bath, and consequently at the speed at which the setting of the metal
takes place along their surfaces, and thus the flux is dissolved and washed off
before it can become burnt; and any other impurities are, of course, washed away
also. A small amount of water only is required, and the dirty water passes away
at once from the bottom of the washing chamber, and is not used over again. The
sheets retain their heat to a considerable degree while passing between the drying
brushes, and pass out from the drying casing or chamber in a dry condition, so
that there is no need to place them subsequently in a drying stove; and the
rapidity of the whole operation, which is entirely automatic, does not allow time
for oxidation. A considerable saving in labour is effected, and a better and more
uniform appearance of the surface of the sheets ensured.
The apparatus above described is intended, more especially, for use with
apparatus which delivers the sheets automatically from the bath between the
washing brushes above described, and is specially suitable for employment with
delivery rolls of the character of those by which the sheets are delivered from the
galvanizing bath, described in the said former Specification, that is to say, with
the delivery rolls ff above described.

page_text: Having now particularly described and ascertained the nature of our said inven--
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The improved process of washing galvanized sheets, which consists in passing
them between brushes or appliances to which water is supplied and which project
the water in the form of a fine spray and at a high velocity against the surfaces of
the sheets, substantially as described.
2. The improved process of washing galvanized sheets which consists in treating
them in such manner and under such conditions, or as nearly so as may be
practically convenient at the time, that each portion of the surface of a sheet
commences to be washed as soon as the coating metal thereon has set, and in any
case so that the forward portion of each sheet is washed before the coating metal
has set on the hinder portion thereof, substantially as described.
3. The improved process of washing galvanized sheets which consists in entering
then between washing brushes or appliances as soon, or as nearly so as may be
conveniently practicable, as the coating metal has set on their forward ends, and
passing them between such brushes or appliances at the rate of speed at which the
metal sets along their surfaces, substantially as described.
4. An apparatus for use in washing galvanized sheets in which a pair of brushes
or appliances revolve in a casing to which water is supplied, substantially as
described.
5. In apparatus for washing galvanized sheets, the combination of a pair of
washing brushes or appliances revolving in a casing to which water is supplied,
with means by which the sheets are automatically delivered from the galvanizing
bath and carried between the brushes or appliances, substantially as described.
6. In apparatus for washing galvanized sheets, the combination of a pair of
washing brushes or appliances revolving in a casing to which water is supplied,
with means by which the sheets are automatically delivered from the galvanizing
bath and carried between the brushes or appliances, and with means by which the
distance of the brushes or appliances and case from the bath may be readily
adjusted, substantially as described.
7. The improved process of drying galvanized sheets after they have been.
washed, which consists in passing them between a pair of brushes to which
sawdust (sharps or other material suitable for the purpose) is supplied, substantially
as described.
8. An appliance for use in drying galvanized sheets, after they have been.
washed, in which a pair of brushes revolve in a casing to which sawdust (sharps or
other material suitable for the purpose) is supplied, substantially as described.
9. In apparatus for use in drying galvanized sheets after they have been washed,.
the combination of an appliance in which a pair of brushes revolve in a casing to
which sawdust (sharps or other material suitable for the purpose) is supplied,.
with means by which the sheets are automatically delivered from washing apparatus
between such brushes, substantially as described.
10. In apparatus for use in drying galvanized sheets after they have been.
washed, the combination of an appliance in which a pair of brushes revolve in a
casing to which sawdust (sharps or other material suitable for the purpose) is.
supplied, with an elevator by means of which the sawdust (or other suitable
material) falling out from the casing is raised up and deliver into the upper part
thereof, substantially as described.
11. The improved process of washing and drying galvanized sheets, which.
consists in passing them on their passage from the galvanizing bath first between
washing brushes or appliances and then between drying brushes to which drying
material is supplied, whereby dipping the sheets in water and subsequently
drying them in a stove is dispensed with, substantially as described.
12. The improved process of washing and drying galvanized sheets which
consists in conveying them automatically from the galvanizing bath first between.

page_text: washing brushes or appliances and afterwards between drying brushes, substantially
as described.
13. Apparatus for use in washing and drying galvanized sheets, by the instru-
mentality of which the sheets are automatically delivered from the galvanizing
bath and carried forwards through a washing chamber in which brushes or
appliances revolve, and thence through a drying chamber in which brushes
revolve, substantially as described and shewn by the drawings herewith.
14. Apparatus for use in washing and drying galvanized sheets, by the instru-
mentality of which the sheets are automatically delivered from the galvanizing
bath and carried forwards through a washing chamber in which brushes or
appliances revolve, thence through a drying chamber in which brushes revolve,
and finally between revolving cleaning brushes, all substantially as described and
shewn by the drawings herewith.
Dated this 8th day of March 1894
STEPHEN WATKINS,
Wolverhampton, Agent for the Applicants.