Improvements in Apparatus for Drying Offal and the like.
Year: 1886

page_text: Improvements in Apparatus for Drying Offal and the like.
I, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P.A. of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, in the County of Lancaster, and
323 High Holborn, in the County of Middlesex, Civil Engineer do hereby declare the
nature of this invention (a communication from abroad by Valerius D. Anderson
of Cleveland, in the State of Ohio, United States of America, Inventor,) 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 apparatus for drying offal and refuse, particularly such
as comes from rendering tanks in which the offal from slaughter houses is cooked.
The apparatus consists of a series of connected pipes of large diameter, passing
through a steam boiler or drum, and forming a continuous passage for the travel
of the material, shafts extending axially through the pipes and provided with
inclined blades to advance and stir the material, and a fan or equivalent device for
producing a current of air through the pipes in a direction opposite to the travel
of the material.
In the annexed drawings:
Figure 1 is a perspective view of the improved drier with the casing partly
broken away.
Figure 2, a rear end view partly broken away.
Figure 3 a vertical transverse section on the line x-x of Figure 4.
Figure 4 a vertical longitudinal section on the line y―y Figure 3.
Figure 5 a detail view.
.
The purpose of this invention is to produce a drying apparatus in which the
material of the character mentioned may be rapidly dried and pulverized in large
quantities, with steam heat instead of the direct heat of a fire.
It has been determined by experience that the direct heat of fire, and even of
superheated steam, is unsuitable for drying material of the character mentioned,

page_text: and greatly impairs the value of the finished product as a fertilizer for which
purpose it is extensively used.
To overcome this difficulty it has been proposed to use steam as a heating agent
in such machinery, but to do this requires a much larger travel of the material,
than where the direct heat of a fire is used and so long a travel that it is,
impracticable to make the cylinder or passage in one straight and continuous body,
and to extend and drive the shafting through the same from end to end.
To avoid the necessity of so doing the inventor employs the series of pipes
arranged parallel, and connected with each other at opposite ends alternately, s0
that the same effect is secured that would be done by the continuous straight
cylinder, and in order to get the requisite fall of the material without undue
height of apparatus the pipes are set alternately to one and the other side of a
given vertical plane.
Prior to this invention such pipes have been connected end to end, but placed
one directly above another in a chamber requiring extensive stay-bolting and thus
the cost of manufacture has been unduly great.
The passing the pipes through a cylindrical steam boiler obviates the necessity
of such stay-bolting; secures the necessary space for proper and convenient
location of the pipes with reference to the delivery of material from one to another,
and produces a machine, the steam drum or body of which can be procured ready
for use, as a regular article of trade, thus greatly facilitating the manufacture and
the placing of the apparatus upon the market.
With all prior apparatus of this class known to the inventor there has been
a considerable amount of dust discharged into the atmosphere causing much
inconvenience and annoyance.
By the use of a fan at the receiving end of the apparatus and producing a
current of air through the machine from the discharge to the receiving end, the
fine dust is carried back into the upper tubes or chambers where it encounters the
moisture of the undried material and is deposited in the mass so that little or none
of the dust passes to the fan.
Another and far more important result of using the fan at this point is that the
steam and moisture are carried off by the air current and the drying is greatly
facilitated, the deposit or collection of the dust in the manner described permitting
the use of a strong air current and the consequent rapid withdrawal of steam and
vapor, which would otherwise be impracticable.
Referring now to the drawings:-
A indicates the shell of a cylindrical steam boiler, riveted together as usual,
and B, C, D, indicate three large pipes passing longitudinally through said shell at
different levels, and projecting beyond the ends thereof as shown in Figure 4,
though such projection is not essential.
The pipe B is provided at its front end with a supply hopper or inlet T, to
receive the material to be treated, and is placed at a higher level than pipès C
and D.
At the rear end of the apparatus the pipe B is cut away on one side to permit
the escape of material therefrom to pipe C, which is placed below pipe B and to
one side, as shown in Figures 1, 2 and 3.
From the opening a thus formed the material passes to a similar opening b, in
the side of pipe C at its rear end, the material being conducted from one opening
to the other by a head or cap E connecting the two pipes, and tightly closed to
prevent escape of steam, vapors or liquid.
In order to get pipes of adequate size within the boiler without making the
latter unduly large or wasting space, the difference in elevation or level is
necessarily made comparatively slight, and does not give the heads or caps E
sufficient inclination to cause the descent of the material if delivered thereon
hence in forming the outlet a, the pipe is cut away only from the top to a point
above the bottom at the discharge side, leaving a raised edge c, over which the

page_text: material is raised and from which it falls freely to the opening 6 of the pipe
below.
The material as it is raised up over the edge c falls upon the inclined bottom of
the cap E in a thin even stream and breaks up any lumps or masses that may be
formed, thus facilitating the drying by exposing all the particles to the heat.
The same arrangement of outlet a inlet b, edge c, and head or cap E is used at
the front end of the machine to connect the pipes C, D, and the rear end of pipe D
is formed with an outlet or discharge opening d, as shown in Figure 3.
Within the pipe B and concentric therewith is a shaft F provided at its forward
end beneath the supply hopper or inlet and for a short distance beyond, with a
series of radial blades G, arranged in a spiral row above the shaft, and set with
their edges at or nearly at right angles to the axis of the shaft, for the purpose of
dividing up the pulpy mass of material delivered into the machine.
Beyond the blades G and to the rear end of the pipe or cylinder, to which point
the shaft extends, the shaft is provided with radial arms carrying broader blades
or paddles H set at an inclination to the axis of the shaft to feed the material
along while stirring, turning and mixing it, the arms being arranged in a spiral
line about the shaft so that the blades produce, jointly, a spiral conveyor.
In like manner a shaft I passes longitudinally and centrally through the pipe or
cylinder C, a shaft J passing through the pipe or cylinder D, each provided with
blades or paddles H.
Shaft F is provided with a gear wheel e at its rear end, which receives motion
through a pinion f from any convenient source, and gives motion to a gear wheel g
on the rear end of shaft I.
Shaft I is furnished at its front end with a gear wheel h which meshes with a
gear wheel i on the front end of shaft J.
In this way all these shafts are caused to rotate, the first in one direction, the
second in the reverse direction, and the third in the same direction as the first, an
arrangement which is advantageous in that it causes the material to be turned
first in one direction and then in another. It also avoids the presence of any
gearing at the discharge end of pipe D.
K indicates a fan, located at one side of the feed hopper or inlet T, which hopper
being kept filled with material, permits a little or no air to enter through it. This
fan is arranged to draw air from the interior of pipe B, and as said pipe is con-
nected with pipes C and D and has no other inlet, air will be drawn in at the
discharge outlet d, and pass through pipe D, thence through pipe C, and finally
through pipe B, leaving all dusty matters behind and emerging from the fan case
laden with moisture and vapors.
The boiler is adapted to contain water for the generation of steam and is also
furnished with inlet and outlet pipes M and N, provided with suitable valves O
and P, to regulate the inlet and outlet of steam in case it is desired to produce the
steam in a separate generator and to introduce it into the boiler or shell A in
that form.
In order to adapt the apparatus for use in either way at will, the boiler A is set
in a suitable chamber Q containing a fire pot, ash pit, a grate R and a chimney or
smoke stack S as for an ordinary steam boiler.
If used in this way, the usual pressure gauge, water gauge, gauge cocks, safety
valve and other appliances will of course be provided and in fact they will
ordinarily be supplied in every case to permit the apparatus to be used in either
way at will.
The pipes B, C, D, and the boiler A being all cylindrical, require no stay bolts,
and are cheap in construction, durable, and easily kept tight, whereas any structure
for this purpose requiring stay-bolts will soon leak around such bolts, permitting
steam to enter the space containing the material under treatment, and to prevent
the proper drying thereof. Such leakage also causing waste of steam and escape
of vapors and odors into the atmosphere.
The pipes must of course be smooth or without projections on the inside.

page_text: By extending the pipe out beyond the boiler at each end the gearing can be
placed where it is easy of access, and where it may be oiled and repaired as
occasion requires.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated
to me by my foreign correspondent, I declare that what I claim is :-
1. The herein described drying apparatus consisting of cylindrical boiler A,
longitudinal pipes B, C, D, heads or caps E shafts F, I, J, provided with blades H,
feed inlet T, and fan K, located at the feed inlet all combined and arranged to
operate as set forth.
2. In combination with boiler A; pipes B, C, D, therein, connected by caps E,
shafts F, I, J, mounted in said pipes, meshing gear wheels e, g, secured to the rear
ends of the shafts F, I, a pinion mounted on the machine and meshing with gear e,
and intermeshing gear wheels h, i, secured to the front ends of shafts F, I, whereby
the shafts are turned in reverse directions and the outlet of pipe D is left
unobstructed.
3. In combination with cylindrical shell A, pipes B, C, D, connected at their
ends by.caps E, the pipes B and C being severally provided with opening a and
raised edge c at the lower side of the opening, substantially as and for the
purpose explained.
4. In combination with boiler or shell A, having steam inlet and outlet
openings M N, pipes B, C, D, heads E, and conveyor shafts F, I, J, chamber Q,
containing fire grate R, and provided with stack or chimney S, whereby the
apparatus is adapted to be operated with steam from an outside source, or to
generate its own steam, substantially as set forth.
5. In a drier, the combination with chamber Q boiler A, set therein, pipes B,
C, D, carried by said boiler, and communicating with each other as shown,
conveyors within the pipes, gearing for giving the requisite motion to the
conveyors; a supply inlet, a discharge opening; and an exhaust fan at the supply
opening as and for the purpose set forth.
6. In combination with a steam jacket or drum, and pipes forming a continuous
passage extending back and forth through the same at different levels, conveyors
adapted to move the material through said pipe or passage in one direction, and
a fan adapted to produce a current of air through said pipes or passage in the
opposite direction; whereby the dusty particles are prevented from escaping into
the atmosphere, and the moisture is withdrawn from the material in all parts of
the apparatus.