IMPROVE- MENTS IN APPARATUS FOR MIXING DRY POWDERED SUBSTANCES
Year: 1877

page_text: LETTERS PATENT to Henry Faija, of Great Queen Street, Westminster, in
the County of Middlesex, Civil Engineer, for the Invention of "IMPROVE-
MENTS IN APPARATUS FOR MIXING DRY POWDERED SUBSTANCES."
Scaled the 22nd September 1877, and dated the 27th March 1877.
PROVISIONAL SPECIFICATION left by the said Henry Faija at the Office
of the Commissioners of Patents on the 27th March 1877.
HENRY FAIJA, of Great Queen Street, Westminster, in the County of Middlesex,
Civil Engineer. "IMPROVEMENTS IN APPARATUS FOR MIXING DRY POWDERED
SUBSTANCES."
My Invention has for its object improvements in apparatus for mixing dry
powdered substances. The substances to be mixed are fed by a hopper to a set of
adjustable rollers for breaking up lumps, thence the substances pass between a
second set of adjustable rollers, whereby the requisite subdivision of the particles is
completed. From the second set of rollers the powders descend into a mixing
vessel furnished with curved blades or stirrers carried by spindles, which are caused
to rotate upon their own axes, and to revolve around the vertical axis of the mixing
vessel.
By a spring device or equivalent means the blades or stirrers are caused to bear
gently against the bottom of the mixing vessel, accommodating themselves to any
inequalities in the surface thereof, and scrapers are caused to bear similarly against
the lower lateral portion of the mixing vessel. By this arrangement I ensure action
upon the entire body of powdered substances, so that their intermixture shall be
thoroughly effected.
The blades or stirrers, with their spindles and actuating apparatus, and the
scrapers are capable of being raised above the lower portion of the mixing vessel, so
that its bottom, or the vessel itself, may be removed as required for taking out the
substances when mixed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Faija in the Great Seal Patent Office on the 24th September
1877.
HENRY FAIJA, of Great Queen Street, Westminster, in the County of Middlesex,
Civil Engineer.
"IMPROVEMENTS IN APPARATUS FOR MIXING DRY POWDERED
SUBSTANCES."
My Invention has for its object improvements in apparatus for mixing dry
powdered substances. The substances to be mixed are fed by a hopper to rollers,
whereby the requisite division of the particles is effected. From the rollers the
powders descend into a mixing vessel furnished with curved blades or stirrers
carried by spindles, which are caused to rotate upon their own axes, and to revolve
around the vertical axis of the mixing vessel.
By a spring device or equivalent means the blades or stirrers are caused to bear
gently against the bottom of the mixing vessel, accommodating themselves to any
inequalities in the surface thereof, and scrapers are caused to bear similarly against
the lower lateral portion of the mixing vessel. By this arrangement I ensure action
upon the entire body of powdered substances, so that their intermixture shall be
thoroughly effected.
The blades or stirrers, with their spindles and actuating apparatus, and the
scrapers are capable of being raised above the lower portion of the mixing vessel, so
that its bottom or the vessel itself, may be removed as required for taking out the
substances when mixed.
Fig. 1 of the Drawings is a front elevation of my improved apparatus; Fig. 2 is
a vertical section; Fig. 3 is a sectional plan in the line 1, 2, of Fig. 1; Fig. 4 is a
sectional plan in the line 3, 4, of Fig. 2.
A is a hopper wherein the powders to be mixed are placed; B, B¹, are rollers
between which the powders are drawn in, and which thoroughly crush all lumps,
and also act as a feed to the mixers; one roller (B¹) is made to go faster than the
other so as to give a grinding action. C is the mixing vessel into which the
powders fall from the rollers; Y, Y, are blades or stirrers, which not only rotate
about their own axes, but also revolve around the vertical axis of the mixing vessel.
This action is accomplished by the use of a central fixed pinion D, through the centre
of which works a spindle E, which carries the blades or stirrers; F, F, are arms fixed
on the spindle E; they carry a loose pinion G, and the blades or stirrers Y. The
pinion G gears with the fixed pinion D and with a pinion H, which is keyed into the
stirrer spindle; it will be evident that as the spindle E rotates it will carry round
the arms F and the blades or stirrers, and that as the pinions keyed into the
stirrer spindles are geared by means of the intermediate pinion G to the central
fixed pinion D; the stirrers will not only have a circular motion around the mixing
vessel, but will also rotate about their own centres in a reverse direction, and, being
formed with a slight twist, the stirrers will turn the materials over and over, and
thoroughly incorporate them. I is a scrapor which travels round the mixing vessel,
and throws the powders on to the stirrers; this scraper is fitted loosely on to the
arm Z, and is kept to the bottom of the mixing vessel by means of a spring, as
shewn; the scraper in form somewhat resembles a ploughshare, so that its shape
always tends to keep it close to the sides of the mixing vessel. By this arrange-
ment, the friction which would result from the use of a fixed scraper is avoided,
and the scraper adjusts itself to any inequalities of the vessel.
The scraper and stirrers are allowed to rest freely on the bottom of the mixing
vessel, so as to be always in contact with it. The spindle E has a square top
which works freely in the bevel wheels K, admitting of ready adjustment to all
inequalities. But
have found it advisable in practice not to allow the entire
weight of the stirrers, scraper, and other parts to rest on the bottom of the mixing
vessel, therefore the lever L, which is forked at one end to pass under a loose collar

page_text: on the spindle E, is at its other end held down by a spiral spring M, and may be so
adjusted that the stirrers may work lightly on the bottom of the mixing vessel.
The bottom N of the mixing vessel is made moveable, and is in reality a slide,
when the powders are mixed (which may be ascertained by opening the trap O), the
handle of the lever L is pushed down, and is held in that position by means of a
catch. This action lifts the stirrors and scraper off the bottom of the mixing vessel,
which can then be drawn out, when the mixed materials will fall through into any
receptacle placed to receive them.
The machine may be worked by either steam or manual power. The main shaft
P gears by means of bevel wheels with the stirrers, and by means of cog wheels with
the rollers.
The apparatus is shown with a sifter, which consists of a light framework X
(which carries the sieve X'), hung by chains to the under side of the mixing vessel;
the seive is moved backwards and forwards by means of the connecting rods Q
worked by the crank shaft R, which in its turn is driven by means of a strap from
the main shaft P.
The operation of the machine is as follows:-The powders are first placed in the
hopper A, thence they pass through the rollers into the mixing vessel, and when
they are mixed, the slide N is withdrawn, and the powders fall into the sieve; the
slide is then replaced, and the same mixing operation repeated while the previous
mix is being sifted, thus securing a continuous delivery. All other mechanical
mixers heretofore proposed to be used have so far as I know been open to objection
owing to lack of proper provision for thoroughly cleaning in such a manner that the
same machine might be used for mixing different compounds. Now by my Invention
I obviate this inconvenience. The back S of the roller case is made moveable; the
hopper A may be taken away, and the back of the lead T may also be removed,
leaving the rollers, hopper, et cætera, perfectly free and easy of access.
The spindle
E, which carries the stirrers, may be easily withdrawn by knocking out the pin U,
thus enabling the mixing vessel and the stirrers to be thoroughly cleaned. The
front of the siove case is made moveable, so that all the inside of the case may be
cleaned, and the sieve changed to suit requirements. The rollers and all the metal
in the machine are by preference tinned, so that no chemical action may be set up
between any powders used and the metal. The hopper, mixing vessel, sieve case,
et cætera, are all lined with tin plate for the same purpose, and also to prevent
secretion of powder; and for facility of cleaning, the gearing on the arms F is all
boxed in, and thus kept from contact with the materials under treatment; the
operations of mixing and sifting are therefore performed wholly within the machine,
wherein all dust is confined.
Though in practice I found it advisable only to have two stirrers, the one working
at a higher level than the other, and overlapping in the centre of the mixing vessel;
it may for some purposes be found convenient to adopt more or less than two.
The diagram Fig. 5 shews the travel of the two ends of a stirrer where six
stirrers are arranged to revolve about a central one. By making the central fixed
pinion with such a number of teeth as shall be indivisable by the number of teeth
in the stirrer pinion, as for instance 41: 10, the same stirrer will never come to
the same place in the mixing vessels until after the number of revolutions cor-
responding to the larger number of teeth, thus ensuring that the entire surface of
the mixing vessel shall be entirely covered by each stirrer. In some cases the
hopper and crushing rollers may be dispensed with altogether, or another form of
crusher and feed apparatus may be substituted, as for instance, an arrangement
resembling a pug mill.
Fig. 6 shews a modification which will be readily understood from the Drawings
without further description.
Having described the nature of my said Invention, and explained the manner of
carrying it into practical effect, I desire to have it understood that I do not intend
to claim as of my Invention or the exclusive use of any of the mechanical parts
herein-before described and shewn when used separately and apart from the combina-

page_text: tion or application thereof in manner and for the purposes herein-before described,
but what I consider to be novel and original, and therefore claim as secured to me
under the Letters Patent herein-before in part recited is, the construction of ap-
paratus, as herein-before described, and shewn in the Drawings, for the purpose
specified.
In witness whereof, I, the said Henry Faija, have hereunto set my hand and
scal, this Twenty-fourth day of September, in the year of our Lord One
thousand eight hundred and seventy-seven.
H. FAIJA. (L.S.)