IMPROVEMENTS IN FILTER PRESSES."
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Gustav Valentin Alsing at the Office
of the Commissioners of Patents on the 1st November 1879.
GUSTAV VALENTIN ALSING, of Bradford, in the County of York, Civil Engineer.
IMPROVEMENTS IN FILTER PRESSES."
This Invention consists in an improved method of and apparatus for pressing
liquid out of matters such as sewerage sediment.
In carrying out this Invention I construct a filter-press in the following
manner :-
I make a proper stand of iron or wood or other suitable material, consisting of
two parallel bars fixed horizontally. Each end of the bars carries a roller or pulley
moving between the bars, and over which a filter cloth fixed as a belt travels
horizontally, and is made of canvas or any other suitable material.
Above each of these two pulleys another pulley of similar construction is placed,
around which also a filterbelt like the before mentioned moves.
When the pulleys are made to rotate by means of suitable gearing, the two filter
belts move or travel in the same direction, but do not touch each other; a space
being left between them according to the thickness of the layer of matter to be
passed. The upper belt is shorter at one end so that the matter to be operated on
can be spread on the under belt. The matter is thus carried forward on the under
belt and between the two belts till it reaches the press frames. These frames I
construct of iron or wood or other suitable material, which may be made square, or
any other suitable shape.
One of these frames is fixed horizontally between the upper filter belt and the
pulleys, and has a cover fixed airtight to its upper surface with a suitable inlet
connected with an air compressing pump or receptacle of compressed air. The
under surface of the frame is open, and is just kept above the underpart of the top
belt.
The other frame is also placed horizontally, but between the underbelt and
exactly below the top frame; it can be moved up and down so that by pressure
can be pressed against the top frame, and thus press the two belts between the
frames.
Both surfaces of the underframe are covered with perforated lids as an outlet for
the liquid pressed from the matter between the belts.
The underframe may be pressed up against the top frame by means of levers,
screws, or any other suitable method; but I prefer to do it by compressed air acting
on a lever or wheel in connection with the frame.

page_text: When the matter to be pressed has travelled until it comes below the press
frames, suitable gearing throws the belt out of motion, enables the compressed air to
lift the under frame up against the top frame and hold it there until the compressed
air, which now is made to enter the top frame, has pressed the liquid out of the
matter between the belts through the perforated lids in the underframe. The
compressed air is then turned off, and the bottom frame resumes its former position,
thereby frees the belts, which again are set in motion by their pulleys being brought
into gear. As soon as the belts have travelled the distance or length of the frames,
the same operation as before is repeated, and the pressed out matter delivers itself
at the other end of the belts, or can be scraped off by suitable constructed and fixed
scrapers.
The feeding to the press can can be made by machinery through a hopper situated
at one end of the apparatus, and thus the filterpress becomes self-feeding and self-
emptying; the filter cloth does not require to be removed until it is worked out,
which hitherto has been the case with other filterpresses.