IMPROVEMENTS IN OR CONNECTED WITH SUCTION BOXES FOR PAPER-MAKING MACHINES
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Robert Wilson Loch and George
Bird at the Office of the Commissioners of Patents on the 5th August 1879.
ROBERT WILSON LOCH and GEORGE BIRD, both of Leith, in the County of Mid
Lothian, North Britain, Engineers. "IMPROVEMENTS IN OR CONNECTED WITH
SUCTION BOXES FOR PAPER-MAKING MACHINES."
"
This Invention has principally for its object to diminish the wear and tear to
which in ordinary paper-making machines the "wire or endless wire gauze cloth
is subjected whilst passing over the suction boxes, and in consequence of its great
friction on such boxes as ordinarily constructed.
With ordinary suction boxes the wire is supported by and rubs on the top edges
of the boxes, and on bars fixed across the tops of the boxes; but by the present
Invention the wire is entirely supported on rollers whilst passing over the suction
boxes, and these rollers are driven by gearing so as to have the same surface
velocity as the wire, so that there may be practically no friction between the wire
and the rollers. A partial vacuum being maintained in the suction boxes, as is well
understood, for the purpose of drawing the water from the pulp which is being
carried along by the wire, it is necessary to combine with the rollers certain
appliances to prevent the passage of air into the suction box excepting through the
pulp and wire, and it is also necessary that the area subjected to the suction
should be adjustable in width to suit whatever width the deckles are set at. In
the case of a suction box of ordinary width, three of the rollers which may be of
brass or other suitable metal or alloy are placed in one box, and the outer sides of
the two outer rollers, which sides are close to the insides of the forward and after
sides of the box are in contact with movable closing pieces of wood or other
suitable material or compound, which are pressed against the rollers by springs.
These closing pieces fit closely down upon the tops of the box sides, and are
inclined so as in each case to form an angular channel along the roller, in which
channel water gathers and assists in preventing the leakage in of air. The box is
made practically airtight at the ends by movable end plates, which are shaped
conformably to the bottoms and sides of the box, also to the circumferences of the
rollers; and also to the underside of the wire at the parts between the rollers. The
end plates are adjustable by means of handled rods passing through holes in
the fixed ends of the box; and these handled rods are also made available for
adjusting the tightness of fit between the movable plates and the box, the rods

page_text: being screwed into the main parts of the plates, and acting by collars formed on
them on small plates between which and the main parts a sheet of vulcanized
rubber is held. The rubber is by screwing the rods made to project more or less
beyond the edge of the plate and form a tight joint. The parts of the plates round
the rollers are made sufficiently tight with packing.
Another improvement consists in equalising the suction in each box by
connecting it by two or more branch pipes instead of one to the main suction
pipe; or by fixing inside the box partitions placed so as to distribute the action.