Improvement in Safety Devices for Grain Mills.
Year: 1891

page_text: Date of Application, 8th Sept., 1891-Accepted, 17th Oct., 1891
COMPLETE SPECIFICATION.
Improvement in Safety Devices for Grain Mills.
We, LOUIS WAGNER and JOHN MARR, both of Baltimore City, in the State
of Maryland, United States of America, Engineer and Maltster, respectively, 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 an automatic safety device for mills.
The invention has for its object to provide mechanism for avoiding the damage
that follows an explosion, and also to prevent fires that usually follow such
explosions.
Referring to the accompanying drawings,
Figure 1 is a side elevation of a roller-mill with the improvements attached.
Figure 2 is a vertical section of the same.
For the purpose of illustrating the invention an ordinary malt mill is here
shown.
The letter A designates the hopper of the mill, a are the rollers or grinders
of any approved kind enclosed in a case C, terminating in a funnel, and a conduit
pipe D leads from said case-funnel to an elevator or a receptacle. The case and
hopper are supported by the frame B.
The journal, a', of one roller a, turns in a stationary box or bearing, b, on the
frame B, while the journal, «³, of the other roller, a, turns in a movable box, b',
which rests in the horizontal slide-way, c.
The journals at both ends of these rollers are mounted in the same way.
Both boxes, b', of the movable roller have a side pin d, which passes freely
through a hole indicated by broken lines, in a post, c', at the end of the slideway,
and the end of said pin projects beyond the post. At each side of the case a
lever, e, is pivoted adjacent to said post and near the pivot has at its under side a
right-angled lug or arm e', which bears against the projecting end of the side
pins d; each lever, e, has a weight, e, attached. By this arrangement any hard
foreign substance that may happen to be in the grain, like a nail or piece of metal,
may pass down between the rollers, a, because the roller whose ends, a³, are in the
movable boxes, b', may move sidewise, as the weighted levers, e, will tilt up when
said hard substance gets between the rollers.
The conduit, D, has a contraction f, at the top of which a valve seat, q, is formed
for the plug valve, p. This valve has a tubular neck p', and the hanger-rodj passes
loosely through the neck and also through a stationary guide bar r, extending cross-
wise of the conduit. Thus the hanger-rod ; may move up or down without affecting
the plug valve; or, on the other hand, the plug valve may move up or down
without affecting the hanger-rod.
At the lower end of the contraction is an inverted shoulder or valve seat, g,
and a vertically-movable valve, E, closes upward against this seat; a stud g is
fixed on a cross-bar, g³, and stands upright, and enters a socket, g³, in the bottom
of the valve E; this stud guides the valve. A hanger-rod, j, is attached to this
valve, E, and projects upward, and its upper end is connected with an arm, I, within
the case and mounted rigidly on a rock shaft, I, passing through the case C; the
end of the arm, I, has a slot k, through which the joint pin, passes; thereby
allowing of the necessary lost motion. At the outer end of the rock-shaft, I, is
attached a beam or arm, 1', having a collar, o, which is loose or adjustable along
the beam, and a weight n, hangs from said collar. This counterpoised weight n will
normally sustain the cat off valve, E, and keep it elevated to its seat, g, and prevent
the ground grain passing below; but the ground grain will accumulate above the

page_text: valve E, within the contracted part f, of the conduit, until the weight of such
accumulated grain overbalances the counterpoise-weight n, when the cut off
valve E, will descend sufficient to allow the said ground grain to pass down.
During the grinding operation, therefore, a certain quantity of ground grain will
always be in the conduit above the valve E, and this quantity will fill the contracted
part f, and will serve to prevent gases or fire from passing downward. It will be
seen, therefore, the counterpoise-weight n must not only elevate and sustain the
movable cut-off valve E, but must also sustain the weight of a pre-determined
amount of ground grain that will accumulate thereon; in addition to this a plug
valve p is provided in the conduit, above the cut-off cylinder to entirely close the
conduit.
A vent flue, S, connects with the conduit D, above the plug-valve, and leads
outside of the building, and provides an outlet for the harmless escape of fire, or
the sudden expansion due to an explosion. This flue inclines upward and then
passes up vertically, and where it joins the conduit has a flap valve u, pivoted at r,
at its lower part. When this valve is closed, it stands upright, as shown, and when
open it falls to a horizontal position within the vent flue, S.. This flap-valve has at
its lower edge an arm w, which projects toward the plug valve, p, and serves the
purpose hereinafter described. Attached to the neck p¹ of the plug valve is one
end of a lever, a, which is pivoted on a rod, a¹, extending across the conduit. When
the flap valve is closed, its arm w comes on top of the free end of the plug valve
lever , as shown in Figure 2, and its contact therewith keeps said free end down, and
thereby keeps the plug valve p elevated or in the open position, and the frictional
contact also keeps the vent valve u up or in the closed position. When an explosion
ensues the vent valve, u, will open, and in so doing, its arm, w, will set free the
lever x, and allow the conduit valve to close.
The rock-shaft, v, to which the flap-valve u, is rigidly attached has one end
projecting through to the outside of the vent flue, see Figure 1, and to this outer
end a pulley, y, is attached; a cord, y', is on the brim of the pulley, and a weight, y³,
is attached to and is pendant from the cord. The weight, cord and pulley keep the
flap valve u, normally closed, and if said valve should be forced open by an
explosion, these parts will after the subsidence of the explosion, close the flap-
valve again, and, by the action of the arm, w, on the lever, a, will also raise and
open the plug-valve, p.
It will be seen that provision has been made by the valve E, to retain a certain
accumulation of ground grain in the conduit, to entirely close the conduit by the
valve P, when an explosion occurs, and to allow the sudden expansion or pressure
due to an explosion to escape by the vent valve u; in addition to these features,
the hopper A is provided in its bottom with a valve F, mounted on a rock-shaft F';
when this valve is turned one way the bottom of the hopper is entirely closed, and
no grain can pass down to the rollers;-when the valve is turned the opposite way,
see Figure 2, grain can readily pass down from the hopper. This hopper valve F
is connected with the vent valve u, so that upon the occurrence of an explosion the
former valve will close simultaneously with the opening of the latter, and the
supply of grain will be cut off from the hopper to the rollers or grinders.
One end of the shaft, F1, of the hopper valve projects through the side of the
hopper and has attached a ratchet wheel G, a spring H, suitably secured, engages
with the teeth of the ratchet wheel and serves as a pawl; thus this wheel can
--move one way, but not the opposite way, until the spring pawl H is released.
The ratchet wheel G, has a crank-eye J, up through which a rod K, passes
loosely or freely; the said eye J is swiveled to the wheel G, so that while the
rod K maintains its upright position through the crank-eye the wheel may turn.
A collar Lis on the rod below the crank-eye, and is retained thereon rigidly to
its position, by a set-screw; when this rod is moved upward, it will first slip
through the eye J until the collar L comes in contact therewith, then the further
up movenjent of the rod will turn the wheel G and close the hopper valve F.
The lower end of the rod K is attached to a crank pin y³, on the vent flue

page_text: pulley, y. By this combination of parts when the vent valve u, opens on the
occurrence of an explosion, the connecting parts, to wit: pulley y, rod K and
wheel G, will close the hopper valve F.
Instead of two grinding rollers, four may be used.
This invention may be used in any kind of mill.
Having now particularly described and ascertained the nature of this said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:
1st: The combination of the rollers a, one of which has its journals in movable
boxes b¹; and a weighted lever pivoted adjacent to each of said movable boxes, and
having a lug or arme by which side pressure is brought against said boxes, for the
purpose set forth.
2nd: The combination of the conduit, having an inverted shoulder or valve
seat 9; a valve E below said seat, and closing upward; a cut-off valve p, having
a tubular neck, and located above the valve first mentioned, and closing by a down-
ward movement; a hanger-rod j attached to the first valve, and passing loosely
through the neck of the cut-off valve; a counterpoised arm I supporting the
hanger rod; a pivoted lover a, having one end supporting the cut-off valve; and
a vent valve u, provided with an arm, w, which comes in contact with the stem end
of said lever.
3rd: The combination of the conduit; a vent valve u; a pulley y in connection
with the said valve; and a weighted cord on the rim of the pulley.
4th The combination of the conduit, cut-off valve in the conduit; a vent
valve ; means for connecting these two valves; whereby the one is kept open
while the other is closed; a pulley in connection with the vent valve; and a
weighted cord on the rim of the pulley.
5th The combination of a mill hopper A, provided with a valve F, grinders
below the said hopper; a vent flue valve below the grinders; and connections
between the said vent flue valve and hopper valve, whereby on the occurrence of
an explosion the vent flue valve will open, and the valve in the hopper will close,
and cut off the supply of grain to the grinders.
6th: The combination of a mill hopper A, provided with a valve F, grinders
below the said hopper; a conduit for ground grain, having a cut off valve p; a
valve to vent the conduit; and connection between the said three valves, whereby
the hopper valve and cut off valve will close when the vent valve opens.
7th: The combination of a mill hopper A, provided with a valve F; grinders
below the said hopper; a vent flue valve below the grinders; a ratchet wheel G,
to turn the hopper valve, a crank pulley turned by the vent valve; a connection
between the said ratchet wheel and crank pulley; and a pawl, acting on the ratchet
wheel.
Dated this 20th day of February 1891.
LOUIS WAGNER.
JOHN MARR.