Year: 1887

page_text: Date of Application, 5th July, 1887
Complete Left, 3rd Apr., 1888
Complete Accepted, 4th May, 1888
We, SAMUEL HENRY JOHNSON and CHRISTOPHER CLARKE HUTCHINSON both of
the Engineering Works Stratford in the County of Essex Engineers do hereby
declare the nature of this invention to be as follows:-
Our Invention has for its object the improvement of the construction of filter
presses so as to facilitate the opening of the same after they have been filled and so as
to enable them to be worked at high pressure. Usually the loose or sliding head or
follower of an ordinary filter press has been moved to and fro to open or close the
press by means of a central screw and when the press has had to be worked at high
pressures the screw has had to be made of fine pitch. Many turns of the scrow have
in such cases been required to open or close the press and much time consequently
wasted.
We remedy this by providing the loose or sliding head or follower with a hollow or
tubular boss projecting from the centre of its back and open at its rear end.
The internal diameter of the tubular boss we make large enough to allow the boss
to telescope or slide freely over the screw. We also provide a thrust block which can
be interposed between the end of the screw and the boss for the end of the screw
to work against. This block may either be hinged to the boss or it may in other
ways be made readily removeable from in front of the end of the screw.
When the press is to be opened the screw is turned back until the thrust block
is relieved from pressure-the thrust block is then turned aside or otherwiso
removed from in front of the end of the screw and the sliding head or follower
can be then run quickly back the screw then passing into the interior of the
hollow boss.
To enable one workman at one side of the machine to run back the follower easily
and rapidly we mount the follower on two small wheels running on the side bars of
the machine, these runner wheels we fix on a common axle which moves in journals
and is provided at the end with a crank handle or hand wheel or other equivalent
lever by means of which both wheels can be simultaneously revolved and the machine
is thus opened or closed by turning it in either direction.

page_text: To turn the central screw of an ordinary filter press whenever it is required to do
so we provide a spur wheel gearing into a pinion attached to a capstan or hand wheel
or lever free to revolve and slide on a fixed mandril attached to the screw standard of
the filter press, this arrangement we prefer, but the gear may be arranged so that the
spur wheel is fixed on to the central screw by means of a feather along which the
spur wheel can slide in an axial direction but must revolve with the screw, and in this
case the pinion need not slide axially on the fixed mandril before referred to-In
order to increase the strength of the screw threads and diminish their pitch so that
the screw shall be mechanically more efficient, we employ a form of thread having
flat surface at right angles to the axis of the screw shaft to sustain the thrust when
the press is screwed up, but the side opposite to that on which the thrust comes
is inclined at such an angle to the axis of the screw shaft as to make the surfaco
of attachment of the thread to the shaft the greatest that the pitch will admit.
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page_text: Improvements in the Construction of Filter Presses.
We, SAMUEL HENRY JOHNSON, and CHRISTOPHER CLARKE HUTCHINSON, both of
the Engineering Works, Stratford, in the County of Essex, Engineers, 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:-
Our Invention has for its object the improvement of the construction of filter
presses so as to facilitate the opening of the same after they have been filled and so as
to enable them to be worked at high pressure. Usually the loose or sliding head or
follower of an ordinary filter press has been moved to and fro to open or close the
press by means of a central screw and when the press has had to be worked at high
pressures the screw has had to be made of fine pitch. Many turns of the screw
have in such cases been required to open or close the press and much time con-
sequently wasted.
We remedy this by providing the loose or sliding head or follower with a hollow or
tubular boss projecting from the centre of its back and open at its rear end.
The internal diameter of the tubular boss we make large enough to allow the boss
to telescope or slide freely over the screw. We also provide a thrust block which can
be interposed between the end of the screw and the boss for the end of the screw to
work against. This block may either be hinged to the boss or it may in other ways
be made readily removeable from in front of the end of the screw.
When the press is to be opened the screw is turned back until the thrust block is
relieved from pressure-tho thrust block is then turned aside or otherwise removed
from in front of the end of the screw and the sliding head or follower can be then run
quickly back the screw then passing into the interior of the hollow boss.
To enable one workman at one side of the machine to run back the follower easily
and rapidly we mount the follower on two small wheels running on the side bars of
the machine those runner wheels we fix on a common axle which moves in journals
and is provided at the end with a crank handle or hand wheel or other equivalent
lover by means of which both wheels can be simultaneously revolved and the machine
is thus opened or closed by turning it in either direction.
To turn the central screw of an ordinary filter press whenever it is required to do
so we provide a spur wheel gearing into a pinion attached to a capstan or band wheel
or lever free to revolve and slide on a fixed mandril attached to the screw standard of
the filter press, this arrangement we prefer, but the gear may be arranged so that the
spur wheel is fixed on to the central screw by means of a feather along which the spur
wheel can slide in an axial direction but must revolve with the screw, and in this case
the pinion need not slide axially on the fixed mandril before referred to. In order to
increase the strength of the screw threads and diminish their pitch so that the screw
shall be mechanically more efficient, we employ a form of thread having a flat surface
at right angles to the axis of the screw shaft to sustain the thrust when the press is

page_text: screwed up, but the side opposite to that on which the thrust comes is inclined at such
an angle to the axis of the screw shaft as to make the surface of attachment of the
thread to the shaft the greatest that the pitch will admit.
In order that our said invention may be more fully understood and readily carried
into effect we will proceed to describe the drawings herounto annexed.
to our invention.
Figure 2 is an end elevation.
Figure 3 is a plan, and
Figure 4 is an elevation of a follower.
The
a is the follower having a hollow or tubular boss a¹ projecting from the centre of its
back, of a sufficient internal diameter to receive the screw b. c is a thrust block
interposed between the screw and the boss. This block is pivoted at e¹ (see Figure 4),
and it can be turned out of the way, as shown by dotted lines in that figure, as soon
as a few turns have been given to the screw to relieve it from pressure.
follower a can then he run back, the screw passing into the interior of the hollow
boss a¹. In order to enable the follower to be quickly run back it is mounted upon
two wheels d d running on the side bars e e of the machine. The wheels d run upon
a common axis d' one end of which is provided with a crank handle d². The screw b
has fixed to it a spur wheel which gears with a pinion ffixed to the hand wheel g,
the pinion and hand wheel g are free to slide upon the fixed mandrel f¹ attached to
the frame of the press.
Figure 5 shows the form of screw we adopt in filter presses.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is—
1. A follower for a filter press having a hollow to receive the screw when run back
substantially as described.
2. The follower a provided with the boss a¹ and removable thrust block c sub-
stantially as described.
3. A follower of a filter press mounted on wheels upon a common axis provided
with a handle or other means for turning it substantially as described.
4. A screw of a filter press carrying a spur wheel gearing with a pinion attached to
a capstan or hand wheel or lever revolving and free to slide upon a fixed mandrel
substantially as described.
5. A screw of a filter press having free to slide upon it a spur wheel gearing with a
pinion attached to a capstan or hand wheel or lever substantially as described.
6. A screw of a filter press provided with teeth substantially of the form shown at
figure 5.
7. Our improvements in the construction of filter presses substantially as described.
Dated this 31st day of March 1888.
SAML. H. JOHNSON.
C. C. HUTCHINSON.