IMPROVEMENTS IN MILLS FOR PREVENTING OR CONSIDERABLY REDUCING "DUST EXPLOSIONS WHILST GRINDING OR CRUSHING DRY GRAIN
Year: 1884

page_text: I HENRY JOHN WORSSAM, of Wenlock Road, St Leonard's Shoreditch, in the
County of Middlesex, Engineer, do hereby declare the nature of my said invention
for IMPROVEMENTS IN MILLS FOR PREVENTING OR CONSIDERABLY REDUCING
"DUST
EXPLOSIONS WHILST GRINDING OR CRUSHING DRY GRAIN," to be as
follows:-
"
This Invention relates to what is termed "dust explosions" which occur whilst
grinding or crushing malt or other dry grain. These explosions are supposed to be
caused by small flint stones, nails, or lucifer matches, passing between the grinding
or crushing rollers and igniting the dust below such rollers; the dust boing caused
by the powdered grain falling into a hopper or other receiving vessel below.
The object of the Invention is to prevent or considerably diminish such
explosions.
In carrying my said Invention into practice I cut off direct communication
between the grinding rollers and the receiving vessel below by fixing under such
rollers two or more smaller rollers made of or covered with India Rubber, Leather
or other soft substance; or they may be made of wood or metal, smooth or grooved,
where found necessary or desirable.
The said small rollers have their surfaces in contact with each other and the two
grinding rollers, they are driven either by suitable gearing or by friction from the
grinding rollers. I give the small rollers a light pressure to keep them up to
their work; for this purpose they run on bearings fixed on levers, with either a
spring or a weight to keep their surfaces in contact.
The ground grain, passing between the grinding rollers, falls into the space
between the small rollers, but is not able to pass through them in consequence of
their revolving in the wrong direction; the said space would be partially filled
with the ground inaterial, and it would pass over the tops of the small rollers, and
between them and the grinding rollers, and fall into the receiving vessel below; or
the ground grain could be guided to pass between the small and grinding rollers
•

page_text: by a fixed guide-bar, made and arranged so as to occupy as much of the space as
possible, leaving just sufficient room for the ground grain to pass.
If a lucifer match, stone, nail or any other material in passing between the
grinding rollers, gets hot or ignited, the only dust it could ignite would be the
very small quantity floating in the space between the rollers; and if an explosion
did occur, it would be of so small a magnitude that no damage would be done;
and even supposing a Lucifer match to pass alight between the grinding rollers,
in passing between a small roller and a grinding roller, it is immediately
extinguished.

page_text: I HENRY JOHN WORSSAM, of Wenlock Road, St Leonard's, Shoreditch, in the
County of Middlesex, Engineer, do hereby declare the nature of my said invention
for "IMPROVEMENTS IN MILLS FOR PREVENTING, OR CONSIDERABLY REDUCING
DUST EXPLOSIONS,' WHILST GRINDING OR CRUSHING DRY GRAIN," 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 what are termed 'dust explosions,' which occur whilst
grinding or crushing malt or other dry grain. The explosions are supposed to be
caused by small flint stones, nails, or lucifer matches, passing between the grinding
or crushing rollers, and igniting the dust below such rollers; the dust being caused
by the powdered grain falling into a hopper, or other receiving vessel below.
The object of the invention is to prevent or considerably diminish such
explosions.
In order that my said invention may be more fully understood, and be more
readily performed, I will explain the same with the aid of the accompanying
drawing, which forms part of this specification; reference being made thereto by
the numerals and letters marked thereon, which reference applies to each figure of
the said drawing where the same index numerals and letters appear.
Fig. 1 is a front elevation; fig. 2 is an end view; and fig. 3 is a plan of my
improved apparatus.
In carrying this invention into practice, I cut off direct communication between
the grinding rollers a, a¹ and the receiving vessel below, by fixing two smaller
rollers b, b', as shown, made of wood, metal, or other suitable material, and covered
with leather, india-rubber, or any other suitable soft material. These rollers run
on spindles, with a plate at each end of the rollers, which plate moves slightly on
a pivot on two levers h. The rollers b, b' are so fixed as to have, by a slight
pressure from the levers h, their surfaces in contact with each other and with the
grinding rollers a, a, as shown; they are driven either by suitable gearing, or by
friction from the rollers a, a¹. A saddle-shaped guide plate directs the crushed
material to pass between the rollers a, a¹ and b, b¹.
Two girders g are attached to the framing of the rollers a, a¹ in any suitable
way; and the two levers are fitted to slide upon the said two girders g; the ends
of which levers h are raised, and spiral springs d are fitted thereon, as shown, to
give the necessary pressure to the rollers 6, 6', and to cause them to revolve with
and in the same direction, as the rollers a, αι.
Or I use a guide-plate, k fig. 2, to direct the crushed material between only two
rollers, say a and b'. The course of the crushed material is indicated by the
arrows. The whole of the crushed material passing by only one small roller,
instead of being distributed by two, the rollers are rendered less liable to clog, and
thereby to cease revolving, as the one working small roller is always kept up to its
work, by the means already described.

page_text: In either case, any substance which passes through, or between the grinding
rollers a, a immediately falls upon the guide-plate to the small roller or rollers, and
is carried over by them or it in the direction shown by the arrows; and the
spring d being depressed thereby, are suited to the thickness of the substance
passing through or between the rollers; this can be varied according to require-
ments.
If a lucifer match, stone, nail, or any other material, in passing between the
grinding rollers a, a¹, becomes ignited, the only dust it could ignite would be the
very small quantity floating in the space k¹; and, if any explosion should take
place, it would be of so trifling a character, that not any damage of consequence
could occur; and, even supposing a lucifer match to pass alight between the
grinding rollers a, a', in passing between the small rollers b, b, or between a small
roller and a grinding roller a¹, it would be immediately and effectually
extinguished. It is, however, all but impossible for any explosion to occur, as
the crushed' material would fall so rapidly as instantly to smother any flame from
a lucifer match or flint stone. 3
The rollers may be fixed by any other method which may be found suitable.
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
Firstly The fitting and fixing of two small soft-faced rollers below and
touching the grinding or crushing rollers and each other, and thereby cutting off
direct communication between the grinding or crushing rollers and the open space
below such soft-faced rollers; substantially as herein described.
་
Secondly-The fitting and fixing springs, levers, and girders; and the method'
of mounting the said soft-faced rollers, so as to permit the said soft-faced rollers,
when rotating, to adapt themselves to suit the thickness of the substance or
substances passing between them and the grinding roller or rollers, substantially as
herein described.