Improvements in Apparatus for Removing Measured Quantities of Pulverulent or Granular Materials from a Receptacle.
Year: 1893

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by die Firma FRIED. KRUPP, Grusonwerk, of
Magdeburg-Buckau, in the Empire of Germany, Manufacturers.]
Improvements in Apparatus for Removing Measured Quantities of
Pulverulent or Granular Materials from a Receptacle.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 apparatus which during a unit of time will remove from
a receptacle filled with pulverulent or granular materials an accurately measured
quantity of such materials. The said apparatus comprises a hopper beneath the
delivery opening of which rotates a horizontal plate or table from which the
pulverulent or granular materials falling thereon from the hopper, or a portion of
said materials are or is scraped by means of a blade or metallic strip. If, as is the
case with apparatus of this kind heretofore employed, the material is allowed to
drop freely upon the rotating plate or table, the heap will assume a more or less
pyramidal form, the side of which according to the condition of the material will be
inclined at a smaller or greater angle of slope, and the base of which will spread to
a smaller or greater extent. Consequently under these circumstances the quantity
which is scraped off during the revolution of the plate, can never be accurately
determined. Moreover, with each material the angle of slope changes to a
considerable extent according to the moisture in the air, so that the quantity
conveyed will also vary. This defect is remedied by the devices hereinafter
described, which prevent the formation of the sloped side, and provides for the
material which drops from the hopper upon the uniformly rotating plate being
scraped from the plate only after it has passed full bore through an orifice of known
sectional area. The quantity or bulk of the material scraped off in a given time is
thus exactly equal to the sectional area of the said orifice multiplied by the distance
that would be traversed in that time by the centre of the orifice assuming that
it were moving round with the rotating plate or table. And this quantity
does not change if after leaving the orifice the stream of material alters its form.
Two forms of apparatus constructed according to this invention are represented
in the drawings.
Figure 1 is a vertical section,
Figure 2 is a half plan and a half horizontal section on the line a x of Figure 1,
and
Figure 3 is a section on the line y, y, y of Figure 2 showing one form of the
invention.
Figure 4 is a vertical section partly in elevation,
Figure 5 is a half plan and half horizontal section on the line z z of Figure 4,
and
Figure 6 is a section on the line v of Figure 5 showing a modification of the
invention.
Like letters denote corresponding parts throughout the drawings.
Referring to Figures 1 to 3 a is the hopper; is the rotary plate or table;
c, c are the scrapers, there being two in this case, secured to the hopper. The
hopper a is provided with a bottom plate d, Figures 2 and 3, in which are formed
one or more radial slots e, Figures 1 and 2. To the lower face of the said plate d
at the edge of each slot e which is towards the direction of rotation of the plate
(indicated by the arrow in Figure 2) is fixed a strip or bar f. The lower edge of
Figure 4 is a vertical section partly in elevation,
Figure 5 is a half plan and half horizontal section on the line z z of Figure 4,
and
Figure 6 is a section on the line v v of Figure 5 showing a modification of the
invention.
Like letters denote corresponding parts throughout the drawings.
Referring to Figures 1 to 3 a is the hopper; b is the rotary plate or table;
c, c are the scrapers, there being two in this case, secured to the hopper. The
hopper a is provided with a bottom plate d, Figures 2 and 3, in which are formed
one or more radial slots e, Figures 1 and 2. To the lower face of the said plate d
at the edge of each slot e which is towards the direction of rotation of the plate
(indicated by the arrow in Figure 2) is fixed a strip or bar f. The lower edge of

page_text: this strip or bar is situated at a definite known distance from the upper surface of
the rotating table b, and determines the depth of the mass of materials which can
be carried away by the said rotating table. At the outer edge e² of each slot e the
cylindrical neck al of the hopper a is prolonged down to the table b so producing
cheeks g between which are openings g¹ to allow the materials to escape.
The table is caused to turn at a uniform velocity by the shaft h to which the
table is fixed. The thickness of the annular material carried away by the turning
movement of the plate b is determined by the lower edge of the strip, while the
cheeks and the casing h¹ around the shaft h determine the outer and inner
boundaries of the materials and prevent the formation of a slope in the radial
direction.
Each blade c can be adjusted parallel to itself in such a manner that its edge
moves in a plane containing the axis of rotation of the table b. By this blade it is
now possible to scrape off either the whole stream of material passing beneath the
strip for only a portion of the stream according to requirements. That portion of
the material which is scraped off, then slides along the surface of the blade until it
drops over the edge of the rotating table.
The scraping blade will evidently operate under the most favourable conditions
if it does not change the direction of motion of the separated materials at all or but
very slightly and gradually as there will not then be any stowing or crowding of
the materials. This result is effected in the construction shown, for in all positions
of the blade c its surface is tangential to the circle of division between the materials
removed from the table and those left on the table so that the deflection of the
material scraped off by it is practically nil.
The adjustment of each scraping blade e as shown in Figures 2 and 3 is effected
by turning a hand wheel which is secured upon a screw m adapted to turn in a
support k. In its turning movement the screw displaces a nut which is mounted
on the screw m and slides in the guide k and is secured to or forms a part of the
blade holder i.
In consequence of this construction the scraper c is always displaced in a direction
at a right angle to its surface, so that, when once arranged tangentially to a circle
struck with the axis of the shaft h as centre it constitutes in every position the
tangent of the circle at which the material is separated.
In the arrangement represented by Figures 4 to 6, use is made, instead of the
adjustable scraping blade, of unchangeable scrapers in combination with slots e
which are adapted to be regulated. This form of apparatus has also a hopper a
with a bottom plate d through the radial slots e of which the material to be
measured falls upon the rotary table which then carries it below the strips f to the
curved scrapers c fixed to the hopper a. The strip determines, as in the previously
described apparatus, by the distance of its lower edge from the table b, the height
of the layer lying upon the table and conducted to the scraper. The formation of
the slope towards the periphery is in this apparatus prevented not by the fixed
wall of the casing prolonged down to the table but by a wall g adapted to be
adjusted in the radial direction. This wall forms the downwardly bent part of a
horizontal slide n which according as it is adjusted closes the slot e more or less.
The displacement of each of these slides n and therefore of the wall takes place
by means of the hand wheel o¹ of a screw o held in a support p fixed to the hopper.
By a pointer p', Figure 4, fixed upon the support p, the adjustment of the slide n
is indicated in each case on a graduated scale provided thereon.
A plate q
extending from the rear edge e³ of each slot e down to the table 6 closes the space
beneath and behind the slot and prevents on that side the formation of a slope.
Owing to this arrangement the material falling through each of the slots e on to
the table b is limited behind by the fixed plate 9, exteriorly by the adjustable
wall g and interiorly by the fixed casing of the shaft h.
Accordingly also in this apparatus, when it is in operation, a continuous stream
of material of rectangular transverse section passes through the opening below the
plate, the quantity of the same passing in a given time being equal to the sectional

page_text: area of the said opening multiplied by the distance that would be traversed in the
time by the centre of said area, were it supposed to be turning with the table.
By displacing the slide n. through the medium of the screw o, not only the
sectional area but also the distance of its centre from the shaft can be changed
during the operation. The displacement of the slide therefore effects a change in
the volume of the material conducted away during a revointion of the plate, the
pointer p indicating on the graduated scale the quantities of material conveyed for
each position thereof per unit of time.
By increasing the number of slots e and scrapers, the output of the machine may
be correspondingly augmented.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. An apparatus for removing measured quantities of pulverulent or granular
materials from a receptacle, in which apparatus the materials are arranged to fall
through slots in the bottom of the receptacle, on to a rotating table and into a space
which is so limited by walls as to prevent the formation of sloping surfaces at the
sides of the heap, said materials being then compelled to pass full bore through an
opening of a known sectional area, and being subsequently removed by scrapers, for
the purpose specified.
2. An apparatus of the kind specified in the first claim wherein the limitation of
the space into which the materials fall is effected exteriorly by the fixed wall of the
receptacle extending down to the rotating table, and the change in the output of
the apparatus is effected by displacing the scraper to and from the axis, substantially
in the manner described.
3. The modification of the apparatus, wherein the limitation of the space into
which the materials fall is effected by the bent part of a slide extending downwards
to the rotating table and the radial displacement of which effects a change in the
sectional area of the outlet orifice and therefore in the output of the apparatus,
substantially as described.
4. An apparatus for removing measured quantities of pulverulent or granular
materials from a receptacle, constructed substantially as described with reference
to Figures 1 to 3 or to the modification illustrated in Figures 4 to 6, and operating
as specified.
101 1
L
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.