An Improved Screen-bottom for Bone Charcoal Washing and Filter Tanks.
Year: 1887

page_text: Date of Application, 14th July, 1887.
Specification Accepted, 16th Aug., 1887
COMPLETE SPECIFICATION.
An Improved Screen-bottom for Bone Charcoal Washing and
Filter Tanks.
I, ALBERT GAUKROGER of San Francisco in the county of San Francisco and State
of California, United States of America, Gentleman, 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 a screen-bottom to be used in connection with the tanks in
which the bone charcoal used for purifying purposes in sugar houses or elsewhere
is washed and which invention is applicable to the tanks in which liquor is filtered.
It consists of a suitably shaped casing made of wood, metal, or other suitable
material, and of any desired size, having fine perforated or other screen material
upon its upper and lower surfaces, and in combination with this, a filling of course
sand, fine gravel, or other suitable material, introduced into the screen bottom and
between these surfaces.
I now proceed to describe my invention reference being had to the accompanying
drawings the letters and figures of reference marked thereon like letters referring to
similar parts throughout.
Fig. 1, is a perspective view of my invention showing the top. Fig. 2 is a
perspective view of my invention showing the botton. Fig. 3 is a section through
the centre. Fig. 4 shows its application within the wash tanks.
The bone charcoal which is used for purifying the sugar syrups or other liquids is
withdrawn from the chamber or tank in which the filtering or purifying work takes
place and is removed to washing tanks after it becomes necessary to cleanse it, and
is usually washed out with a sufficient quantity of water, after which it is renovated
by burning and again made ready for reusage.
In my invention A is a frame or casing made of the proper size and shape to fit
the inclined bottoms of washing tanks or the bone charcoal filter tanks, this frame
forming continuous sides of a sufficient depth for the purpose, upon the upper
and lower sides of this frame is fixed a screen material B which may be of perforated
metal as shown, thus forming an inclosed casing, the top and bottom of which
are formed of screening material. Within the chamber thus formed, course sand, fine

page_text: gravel, or other suitable material is introduced through an opening C, into which
may be inserted a suitable plug E until it is completely filled and the screen bottoms
are then put in place as shown in Fig. 4.
A channel or recess D, is made around the lower edge of the screen frame or
casing to receive wood or other packing material strips so as to make a tight joint
around the bottom.
These screens will effectually prevent the loss or escape of fine bone charcoal, and
may be easily removed and cleansed, and the material within them removed and
cleansed whenever desired.
In the application of these screen bottoms to bone charcoal filter tanks already
in use any number can be used for each tank and the frame sides can be made
of concrete stone blocks forming the casing or chamber for the reception of course
sand, fine gravel or other suitable material, proper outlets being provided for each
individual screen and the top and bottom perforated screen material fastened down
in any convenient manner with bolts, screws or otherwise. The channel or recess D
in this case may be dispensed with.
In the application of these screen bottoms to new bone charcoal filter tanks and
new washing tanks, recesses may be made in the castings themselves, in order
to form the chambers or casings for the reception of course sand, fine gravel
or other suitable material, these recesses being provided with their proper outlet for
each individual screen; the channel or recess D, in this case also may be dispensed
with.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is.
1. A screen bottom for bone charcoal filter tanks and bone charcoal washing tanks,
consisting of a frame, forming close sides with a top and bottom formed of any
perforated material in combination with the filling of coarse sand, fine gravel or other
suitable material substantially as herein described.
2. The screen bottom with the perforated top and bottom and intermediate filling
without, or in combination with the packing around the lower edge substantially
as herein described.
3. The screen bottom with the perforated top and bottom and intermediate filling,
without or in combination with the opening C through which the screen bottom
is filled, substantially as herein described.
4. The construction and general arrangement of my said invention, substantially
as and for the purposes hereinbefore described, set forth in the claims and illustrated
in the drawings.