Improvements in or connected with Suction-boxes for Paper-making Machines.
Year: 1890

page_text: Improvements in or connected with Suction-boxes for
Paper-making Machines.
I ISAAC BRATTON of Wilmington Delaware United States Machinist 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 :-
This invention relates to certain improvements in connection with the suction
boxes of paper making machines, the object of my invention being to facilitate the
operation of the machine and improve the product.
In the accompanying drawings
Figure 1 is a longitudinal section of the suction-box of a paper making machine
with my improvements.
Figure 2 a transverse section of the same and
Figure 3 a sectional view of an ejector which I use in carrying out my invention.
A, represents a suction-box of an ordinary Fourdrinier paper machine B the
perforated plate forming the top of the same; D part of the endless web or apron
of wire gauze on which the sheet of pulp is deposited E E the usual deckle straps for
limiting the width of the sheet and FF the adjustable heads or plungers, which
coincide with the deckle straps and are intended to prevent leakage of air into the
suction-chamber G of the box. A partial vacuum being established in said chamber,
the water is drawn from the sheet of pulp as the endless apron D carries the same
over the perforated cover of the box A, the water being drawn from the box through
a pipe H. Ordinarily a pump is used for this purpose and it becomes necessary to
prevent the entrance of air to the suction chamber G, as a mixture of air with the
water would interfere with the operation of the pump, hence it has been usual to seal
the suction chamber by filling the box A with water outside of the adjustable heads F.
A portion of this water finds its way beneath the deckle straps and wets the edges
of the sheet of pulp on the apron D, thus weakening the edges of the sheet and
interfering with the proper uniform drying and calendering of said sheet by the
rollers used for that purpose. In carrying out my invention I dispense with the
usual pump and use in place of the same an ejector J which effects the rapid removal.
of the water from the box A and is not affected in its action by the admixture of air
with the water. For this reason I am enabled to dispense with the water seal for the
heads F, and thus obviate the objections above mentioned and there being no leakage
of air to guard against I am enabled to maintain in the suction-chamber & a condition
more nearly approaching a perfect vacuum than is possible with the pump, the water
being thus rapidly drawn from the sheet of pulp, so that the speed of the apron can
be materially increased without risk of carrying off the pulp while it still retains a
surplus of moisture.
Another advantage of using the ejector in place of the pump is the facility with
which said ejector can be cleansed by passing a current of clean water through the
same.
It is the common practice to convey the discharge from the suction box of the
machine back to the mixing box in order to save the particles of pulp carried off with
the water.
In making colored paper the particles of colored pulp fill the interstices in the
cylinder valve-boxes and other parts of an exhaust-pump to such an extent that it is
difficult to properly clean the latter when changing from the manufacture of paper of
one color to that of another color, or from colored to white paper & in consequence
the first paper produced after the change is apt to be streaky or spotted.
objection is effectually overcome by my invention, there being no parts in the ejector
which would serve to retain the colored particles of pulp so that the thorough
leansing of the ejector can be effected in a few moments.
This

page_text: Incidental to the use of the ejector in place of the pump are the further advantages
of its compactness, its freedom from liability to get out of order, and the facility with
which it can be used in positions where the use of a pump would be impossible.
Various forms of ejectors may be used in carrying out my invention, but the form
which I have found to answer well in practice, and which I prefer, is that shown in
Figure 3, a being the steam-chamber of the ejector, having a branch a', & the inlet
and d the outlet branch. The branch b has a conical end and the branch d a flaring
mouth, and the steam passes from the chamber a through the tapering annular
passage thus formed, the water from the suction box being drawn through the branch b
and forced from the branch d. A free and unbroken flow of water through the
branches and d is thus permitted whereas in an ordinary ejector the water takes a
more or less circuitous course through a contracted passage and when the water
carries with it numerous particles of pulp it has a tendency to clog such a passage
and interfere with the proper working of the device.
I have shown the ejector in a vertical position at the side of the machine but it
may be located wherever convenience or circumstances may suggest.
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:-
The combination of the suction-box of a paper-making machine and its discharge
pipe with a steam ejector connected to said pipe substantially as set forth.
Dated this 21st day of October 1890.
ERNEST SALAMAN,
Agent for Applicant.