IMPROVEMENTS IN APPARATUS FOR MIXING OR STIRRING LIQUID, OR SEMI-LIQUID, OR PULVEROUS SUBSTANCES
Year: 1876

page_text: LETTERS PATENT to Edward Cowles, of Houn low, in the County of Middlesex,
for the Invention of "IMPROVEMENTS IN APPARATUS FOR MIXING OR STIRRING
LIQUID, OR SEMI-LIQUID, OR PULVEROUS SUBSTANCES."
PROVISIONAL SPECIFICATION left by the said Edward Cowles at the
Office of the Commissioners of Patents on the 8th January 1876.
EDWARD COWLES, of Hounslow, in the County of Middlesex. "IMPROVEMENTS
IN APPARATUS FOR MIXING OR STIRRING LIQUID, OR SEMI-LIQUID, OR PULVEROUS
SUBSTANCES."
My Invention relates to that description of apparatus for mixing or stirring
liquid, or semi-liquid, or pulverous substances in which a set of arms or bars
extending from a central shaft are made to revolve inside a vessel containing the
liquid, the arms or bars being made to pass between other arms or bars which are
either fixed to the sides of the vessel, or are made to revolve in a contrary direction
to the first-named arms. With such apparatus as heretofore employed the mixing
is only effected by the agitation caused by the passage of the said arms through
the liquid, and it is consequently very difficult to effectually mix or incorporate
two or more liquids or semi-liquids that, owing to their different specific gravities,
tend to lie in separate layers above each other in the mixing vessel.
Now my present Invention consists in so constructing such mixing apparatus,
that in addition to the agitating effect produced by the passage of the arms
through the liquid, the motion of the arms shall also induce a definite current in
the whole mass of the liquid in the direction from the bottom to the top, or from
the top to the bottom, whereby it will be seen that any stratification of the
liquid will be effectually overcome and the particles of liquid situated in one part
of the vessel be brought into contact with the particles of liquid contained in all
other parts of the vessel. For this purpose I form the said arms or blades with
surfaces inclined, more or less, to the plane of rotation, so that in revolving in a
liquid they propel the same forward in a direction at right angles to their place
of rotation; and I prefer to make such inclined surfaces of a helical form so as to
act in a similar manner to screw propellers. Such a series of rotating helical
blades may be employed by themselves, but, by preference, I use them in com-

page_text: bination with a similar series of blades having spaces between them of sufficient
width to allow those first mentioned to pass between them. This second series of
blades may either be stationary, or they may be made to revolve in a contrary
direction to the first-named set, being connected for this purpose at their outer ends
to a framing which is fixed to a hollow shaft, through which the other shaft passes
in a manner well understood and employed in mixing apparatus of present con-
struction. Or two or more sets of blades may be fixed on revolving shafts
arranged parallel to each other, the one set of blades passing between the spaces of
the other set.
When the second set of blades is made to revolve in a contrary direction to the
first set, as described, the blades are of course also inclined in a contrary direction
to the inclination of the first set, so that they will propel the liquid in the same
direction as the latter.
If the revolving blades are made of such a length as to 'leave a space between
their ends and the sides of the mixing vessel, the effect will be that, while a
current is induced in the liquid in one direction in the central part of the vessel
by the rotation of the blades, a current in the contrary direction will be produced
in the annulus of liquid surrounding the blades, and thus a most effectual mixing
or stirring of the liquid will be effected. This effect may be increased by pro-
viding on the outside of the framing carrying the second set of blades another
series of blades, extending to the sides of the vessel and inclined in a contrary
direction to the other blades, so as to induce a current in the contrary
direction.
In cases where viscous fluids have to be mixed or stirred, I prefer to provide
such additional blades only on one side of the framing, while on the other side I
provide a scraper, passing in contact with the sides and bottom of the vessel.
Also, in some cases, I dispense with the second series of blades, employing only the
one central set in combination with a revolving framing having the just-described
outer blades inclined in the contrary direction.
When two sets of blades are employed, either both revolving or the one set
.stationary, the stationary set, or the one revolving set, may be made without the
inclined surfaces so as to act merely as agitators.
F
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Cowles in the Great Seal Patent Office on the 4th July
1876.
EDWARD COWLES, of Hounslow, in the County of Middlesex.
"IMPROVEMENTS
IN APPARATUS FOR MIXING OR STIRRING LIQUID, OR SEMI-LIQUID, OR PULVEROUS
SUBSTANCES."
My Invention relates to that description of apparatus for mixing or stirring
liquid, or semi-liquid, or pulverous substances, in which a set of arms or bars
extending from a central shaft are made to revolve inside a vessel containing the
substance, the arms or bars being made to pass between other arms or bars,
which are either fixed to the sides of the vessel or are made to revolve in a
contrary direction to the first-named arms. With such apparatus as heretofore
employed, the mixing is only effected by the agitation caused by the passage of
the said arms through the liquid, and it is consequently very difficult to effectually
"mix or incorporate two or more liquids or semi-liquids that, owing to their
different specific gravities, tend to lie in separate layers above each other in the
"mixing vessel.
Now, my present Invention consists in so constructing such mixing apparatus,
that in addition to the agitating effect produced by the passage of the arms
"through the liquid the motion of the arms shall also induce a definite current
in the whole mass of the liquid in the direction from the bottom to the top, or

page_text: from the top to the bottom, whereby it will be seen that any stratification of
the liquid will be effectually overcome, and the particles of liquid situated in one
part of the vessel be brought into contact with the particles of liquid contained in
all other parts of the vessel. For this purpose I form the said arms or blades with
surfaces inclined, more or less, to the plane of rotation, so that in revolving in a
liquid they propel the same forward in a direction at right angles to their plane of
rotation, and I prefer to make such inclined surfaces of a helical form so as to act
in a similar manner to screw propellers. Such a series of rotating helical blades
may be employed by themselves, but by preference I use them in combination
with a similar series of blades having spaces between them of sufficient width to
allow those first mentioned to pass between them. This second series of blades
may either be stationary, or they may be made to revolve in a contrary
direction to the first-named set, being connected for this purpose at their outer
ends to a framing which is fixed to a hollow shaft through which the other shaft
passes in a manner well understood and employed in mixing apparatus of present
construction. Or two or more sets of blades may be fixed on revolving shafts
arranged parallel to each other, the one set of blades passing between the spaces of
the other set.
When the second set of blades is made to revolve in a contrary direction to the
first set, as described, the blades are of course also inclined in a contrary direction
to the inclination of the first set, so that they will propel the liquid in the same
direction as the latter.
If the revolving blades are made of such a length as to leave a space between
their ends and the sides of the mixing vessel, the effect will be that while a
current is induced in the liquid in one direction in the central part of the vessel by
the rotation of the blades a current in the contrary direction will be produced
in the annulus of liquid surrounding the blades, and thus a most effectual mixing
or stirring of the liquid will be effected. This effect may be increased by pro-
viding on the outside of the framing carrying the second set of blades another
series of blades extending to the sides of the vessel and inclined in a contrary
direction to the other blades, so as to induce a current in the contrary
direction.
In cases where viscous fluids have to be mixed or stirred I prefer to provide
such additional blades only on one side of the framing, while on the other side I
provide a scraper passing in contact with the sides and bottom of the vessel. Also,
in some cases, I dispense with the second series of blades, employing only the one
central set in combination with a revolving framing having the just.described outer
blades inclined in the contrary direction.
When two sets of blades are employed, either both revolving, or the one set
stationary, the stationary set or the one revolving set may be made without the
inclined surfaces so as to act merely as agitators.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shews an elevation of a mixing or stirring apparatus constructed according
to my Invention.
To the tubular spindle A carried by the framing B is attached a frame C having
a number of blades C1, C2, with bosses C3 in their middle corresponding in position
with the spindle A. The blades are inclined, as shewn, those being inclined in
the contrary direction to those C2, and by preference they are made as screw blades,
as shewn, that is, inclined at less acute angles to the horizontal plane at the central
boss than at the outer ends. Between these blades are other helical blades D1, D2,
fixed on
a spindle D passing through the hollow spindle A. The blades are
inclined in the contrary direction to those C¹, C³, so that when the two sets are
immersed in the liquid in the pan E and rotated in contrary directions by the
gearing at F, F, F, of well-known construction, they will not only effectually mix
or stir the liquid in their immediate vicinity, but they will at the same time pro-
duce a continuous upward current of the liquid at the centre of the pan, thereby

page_text: also inducing a downward current at the sides thereof, and thus effecting a perfect
circulation of the liquid so that every portion of the latter is successively brought
under the action of the blades. On the outer side of the framing C are fixed or
formed other blades C inclined in the contrary direction to those C, and reaching
to near the side of the pan so as to accelerate the downward flow of the liquid at
that point, and thus assist the circulation. On the other side of the framing may
be fixed a scraper G, which in rotating with the blades will scrape the liquid when
of a viscous nature from the sides of the pan.
The stirring apparatus is mounted in a frame A¹ which can be raised or lowered
on the frame B, so as to enable the pan E to be removed or tilted on trunnions E¹
for pouring out the liquid when stirred.
By means of the bevil wheel F a quick rotary motion is imparted to the stirring
blades. If a slow motion is required, this wheel is drawn out of gear with the
pinions F, F, and a bevil pinion H is put in gear with the pinions H, H, fixed
respectively on the spindles A and D, the crank handle being transferred to the
spindle of H.
Fig. 2 shews an apparatus of similar construction to that just described adapted
for hand use, as the small egg beaters of ordinary construction. The same parts are
indicated by the same letters as in the previous Figure, and need therefore not be
further described.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim, in respect of apparatus for stirring or mixing
liquids,
First. The use of two sets of revolving blades inclined in contrary directions to
the plane of rotation, the one set of blades being caused in rotating to pass between
the other set, substantially as herein described.
Second. The use in combination with the apparatus described in the preceding
claim of outer blades, inclined so as by their rotation to produce a current in the
contrary direction to that produced by the inner blades, substantially as herein
described.
In witness whereof, I, the said Edward Cowles, have hereunto set my hand
and seal, this First day of July, in the year of our Lord One thousand eight
hundred and seventy-six.
EDWARD COWLES. (LAS.)