U.S. patent application number 10/183965 was filed with the patent office on 2003-01-30 for granular material dispensing valve and integral hopper.
Invention is credited to Maguire, Stephen B..
Application Number | 20030021181 10/183965 |
Document ID | / |
Family ID | 26722663 |
Filed Date | 2003-01-30 |
United States Patent
Application |
20030021181 |
Kind Code |
A1 |
Maguire, Stephen B. |
January 30, 2003 |
Granular material dispensing valve and integral hopper
Abstract
A valve for dispensing granular material from a material storage
device having a discharge orifice comprising a member reciprocally
resident within the orifice over at least a portion of the
reciprocal stroke, the member having an aperture therein remote
from the extremities of the member, one end of the member defining
a discharge orifice for granular material dispensed thereby, a
skirt at least partially surrounding the member, having an opening
formed therein and communicating with the member aperture when the
member is at a first position in a range of reciprocating travel,
the opening and the aperture being displaced from one another and
hence in non-communicative relationship when the member is at a
second position in the range of travel, and a piston-cylinder
combination for vertically moving the tubular member within the
range.
Inventors: |
Maguire, Stephen B.; (Glen
Mills, PA) |
Correspondence
Address: |
Charles N. Quinn, Esq.
Fox, Rothschild, O'Brien & Frankel, LLP
10th Floor
2000 Market Street
Philadelphia
PA
19103
US
|
Family ID: |
26722663 |
Appl. No.: |
10/183965 |
Filed: |
June 25, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10183965 |
Jun 25, 2002 |
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09076498 |
May 4, 1998 |
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6467943 |
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60045343 |
May 2, 1997 |
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Current U.S.
Class: |
366/141 ; 141/83;
177/59; 222/58; 366/151.1 |
Current CPC
Class: |
B29B 7/78 20130101; B01F
27/213 20220101; B01F 27/0727 20220101; B01F 23/64 20220101; B01F
27/50 20220101; B01F 27/70 20220101; B01F 35/832 20220101 |
Class at
Publication: |
366/141 ;
366/151.1; 141/83; 177/59; 222/58 |
International
Class: |
B01F 015/00 |
Claims
I claim the following:
1. A gravimetric blender comprising: a. a vertically elongated
rectangular frame having a transparent or open side extending
substantially the vertical height of said housing; b. a material
storage hopper removably mounted on said frame and comprising means
within said hopper and proximate the hopper bottom for dispensing
material within said hopper; c. a weigh bin connected to said frame
below said hopper; d. means connected to said frame for sensing
weight of material in said bin; and e. a mix chamber below said
weigh bin.
2. The gravimetric blender of claim 1 wherein said means for
dispensing material within said hopper includes a valve and means
for actuating said valve, wherein said valve and said valve
actuating means are fixedly connected to said hopper.
3. The blender of claim 2 wherein said actuating means is at least
partially within said hopper.
4. The blender of claim 3 wherein said valve means is at least
partially within said hopper.
5. The blender of claim 2 wherein said actuating means fully within
said hopper.
6. The blender of claim 3 wherein said valve means is fully within
said hopper.
7. The blender of claim 1 wherein said hopper with said valve and
actuating means affixed thereto is manually removable from said
housing.
8. The blender of claim 1 further comprising a plurality of
hoppers, each with valve means therewithin and respective
individual valve actuation means.
9. The blender of claim 1 wherein said actuating means is
pneumatically driven and includes a vertically elongated member for
transmitting motion to said valve.
10. The blender of claim 1 wherein said actuating means comprises a
piston-cylinder combination connected to said hopper wall.
11. The blender of claim 1 further comprising means connected to
said frame for selectably contacting and opening said bin to
release material in said bin downwardly into said mix chamber.
12. The blender of claim 12 further comprising means for biasing an
openable portion of said bin towards a closed position.
13. The blender of claim 13 wherein said openable portion is
movable about a pivot.
14. The blender of claim 14 wherein said openable portion pivots
about a horizontal axis.
15. The blender of claim 12 wherein said means for selectably
contacting and opening said bin in pneumatically actuated.
16. The blender of claim 12 wherein said means for selectably
contacting and opening said bin is a piston-cylinder
combination.
17. The blender of claim 17 wherein said cylinder is outboard of
said housing.
18. The blender of claim 17 wherein said piston moves transversely
to the axis about which said openable portion pivots.
19. The blender of claim 17 wherein said piston contacts said bin
directly.
20. The blender of claim 17 wherein said piston contacts said bin
indirectly.
21. The blender of claim 12 wherein said openable portion is
pivotally connected to a remaining, stationary portion of said
bin.
22. The blender of claim 1 wherein said frame is a single piece of
material.
23. The blender of claim 22 wherein said frame is steel.
24. The blender of claim 22 wherein said frame has three sides, two
of which are parallel and perpendicular to the remaining side.
25. The blender of claim 22 wherein said frame extends vertically
upwardly in a straight line from the bottom of said blender to said
hopper.
26. The blender of claim 22 wherein one side of said frame is
open.
27. The blender of claim 22 further comprising an upwardly
extending removable panel adapted for fitting together with said
frame to provide an enclosure for said weigh bin.
28. A gravimetric blender comprising: a. a housing; b. a weigh bin
mounted on said housing, having an aperture at the bottom thereof
and comprising; i. a movable weigh pan defining a portion of the
bin bottom; ii. a sloped section forming a portion of said bin
bottom and extending downwardly from a bin side; iii. remaining
sides of said bin having co-planar lower extremities; iv. at least
a central part of said pan when said aperture is open being below
said sloped portion; c. means, connected to said housing, for
sensing weight of material in said bin; d. a mix chamber below said
bin and connected to said housing including mixing means
therewithin; e. means for selectably moving said pan between a
position covering said aperture at which said pan defines a portion
of said bin bottom and an position at which said aperture is open
for releasing material in said bin downwardly into said mix
chamber.
29. The blender of claim 28 wherein said sloped section is
planar.
30. The blender of claim 28 wherein said remaining sides of said
bin are of common vertical height.
31. The blender of claim 28 wherein said central part of said weigh
bin in said aperture uncovering position is parallel with said
sloped section.
32. The blender of claim 28 wherein said central part of said weigh
bin and said aperture uncovering position is under said sloped
section.
33. A gravimetric blender comprising: a. a vertically elongated
frame having an open side and defining an enclosure for a weigh bin
and a mix chamber; b. a material storage hopper mounted on said
frame; c. said weigh bin connected to said frame below said hopper;
d. means, connected to said frame, for sensing weight of material
in said bin as received from said hopper; e. said mix chamber below
said bin and receiving material therefrom including rotatable
mixing means therewithin; f. a vertically elongated panel adapted
for fitting together with said frame to close said enclosure, said
panel being transparent; g. drive means supplying rotary motion for
said mixer; and h. means transferring rotary motion from said drive
means to said mixer disconnecting said mixer from said drive means
upon disconnection of said panel from said frame.
34. The blender of claim 33 wherein said means connecting said
mixer to said panel for axial movement of said shaft responsively
to said panel disconnecting from said frame provides movement of
said mixer unitarily with said panel upon panel disconnection.
35. The blender of claim 33 wherein said mixer axis is
perpendicular to said panel.
36. The blender of claim 33 further comprising drive means for
supplying arcuate rotary motion to said mixer.
37. The blender of claim 36 wherein said arcuate rotary motion
supplied by said drive means is fixed in amount.
38. The blender of claim 36 wherein said drive means arcuately
reciprocates said mixing means.
39. The blender of claim 36 wherein said arcuate motion is less
than a full circle.
40. The blender of claim 36 wherein said arcuate motion is greater
than a full circle.
41. The blender of claim 36 wherein said drive means arcuately
reciprocates said mixing means through arcs which are less than
full circles.
42. The blender of claim 36 wherein said drive means is
pneumatically driven.
43. A valve for vertically dispensing a precisely controlled flow
of granular material from a material storage device having a
discharge orifice at a lower extremity thereof, comprising: a. a
vertically reciprocable tubular member axially aligned with and
slidably resilient within said orifice, having a lateral aperture
formed therein remote from the vertical extremities of said member,
a lower end of said tubular member defining a discharge orifice for
granular material dispensed thereby; b. a skirt at least partially
surrounding said tubular member, having a lateral opening formed
therein; c. said skirt opening communicating with said tubular
member aperture when said tubular member is at a first position in
a range of vertical travel, said opening and said aperture being
displaced from one another and hence in non-communicative
relationship when said tubular member is at a second position in
said range of vertical travel; d. pneumatic means for vertically
moving said tubular member within said range.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to methods and apparatus
for providing precisely measured amounts of granular materials
preparatory to further processing of the combined granular
materials and specifically to gravimetric blenders providing
precisely measured amounts of plastic resin material and mixing
these components prior to supplying the blended mixture to plastics
manufacturing and processing equipment such as plastic injection
molding, compression molding and extrusion equipment.
FIELD OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART
[0002] The modern gravimetric blender was essentially originated by
the applicant of this invention and is widely used throughout the
world by industries concerned with precision feeding of granular
material, especially plastic resin material.
[0003] Gravimetric blenders operate by blending solid plastic resin
material components and additives, by weight, in batches. Typically
batches of material may consist of several solid material
components. One of these may be "regrind", consisting of ground
plastic resin which had previously been molded or extruded and
which either resulted in a defective product or was excess material
not formed into a desired product.
[0004] Another component may be "natural" plastic resin which is
virgin in nature in the sense that it has not previously been
processed into a molded or extruded plastic part.
[0005] Yet another component may be a solid color material,
typically flakes or freeze dried material, used to produce a
desired color of the finished plastic part.
[0006] Still yet another component may be an additive used to
adjust the blend to provide required performance characteristics
during molding, extrusion or subsequent processing.
[0007] The gravimetric blender as originated by the applicant and
as copied widely throughout the world typically includes hoppers
for each of the components of the solid material to be blended
together. Typically several hoppers or several compartments in a
hopper may be provided, such as one compartment for "regrind"
material, one compartment for "natural" material, one component for
solid color additive material and one compartment for
"additive".
[0008] When the gravimetric blender operates, the unit desirably
operates automatically, adding each of the component solid
materials in the proper, desired percentages. Each solid material
component is dispensed by weight into a single weigh bin. Once the
proper amounts of each component have been serially dispensed into
the weigh bin, all of the components are dropped together into a
mixing chamber from the weigh bin.
[0009] Mixing is performed, preferably continuously, and preferably
even as additional batches component are dispensed in the mixing
chamber. When mixing is complete, the resulting blend is preferably
provided directly to the desired molding or extrusion machine.
[0010] Feedback control of the dispensed amounts of each solid
material component provided to the weigh bin and measured by weight
assures that in the event of an error in the amount of a dispensed
component, the succeeding batch may have the blend adjusted to
account for the error detected in the preceding batch of blended
material.
[0011] As one of the components forming a part of the resulting
blend it is known to supply solid color additives to the blend in
order to provide a blend of a desired color. These color additives
may be flaked pigments on wax carriers or in freeze dried form. It
is also known to provide the color as pigment powder constituting
one component of the resulting blend.
SUMMARY OF THE INVENTION
[0012] In one of its aspects this invention provides a gravimetric
blender including a frame, a material storage hopper removably
mounted on the frame, valve means proximate the hopper bottom for
dispensing material within the hopper, and means connected to the
hopper and remaining so upon removal of the hopper from the frame,
for actuating the valve means to downwardly dispense material
within the hopper, a weigh bin connected to the frame below the
hopper, means connected to the frame for sensing weight of material
in the bin, and a mix chamber below the weigh bin.
[0013] Desirably, the means for actuating the valve is fixedly
connected to the hopper, the actuating means is at least partially
within the hopper, the valve means is at least partially within the
hopper, the hopper is manually removable from the frame, and it
further includes a plurality of hoppers, each with valve means
therewithin and respective individual valve actuation means. The
actuating means is pneumatically driven and includes a vertically
elongated member for transmitting motion to the valve.
[0014] The gravimetric blender includes a frame, a weigh bin, means
connected to the frame for sensing weight of material in the bin, a
mix chamber below the bin and connected to the frame, means
connected to the frame for selectably contacting and opening the
bin to release material in the bin downwardly into the mix chamber.
The blender further preferably includes means for biasing an
openable portion of the bin towards a closed position; the openable
portion is preferably movable about a pivot; the openable portion
preferably pivots about a horizontal axis; the means for selectably
contacting and opening the bin is preferably pneumatically
actuated; the means for selectably contacting and opening the bin
is preferably a piston-cylinder combination; the cylinder is
preferably outboard of the frame; the piston preferably moves
transversely to the axis about which the openable portion pivots;
the piston may contact the bin directly or indirectly; the openable
portion is preferably pivotally connected to a remaining,
stationary portion of the bin.
[0015] The piston is preferably disconnected from the bin when the
movable portion is at the closed position.
[0016] The means for selectably contacting and opening the bin
further includes
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a front elevation of a reduced size gravimetric
blender illustrating principally, but not entirely, design aspects
of the invention.
[0018] FIG. 2 is a rear elevation of a reduced size gravimetric
blender illustrated in FIG. 1, illustrating principally, but not
entirely, design aspects of the invention.
[0019] FIG. 3 is a left side (with reference to the blender
positioned as shown in FIG. 1) elevation of a reduced size
gravimetric blender illustrated in FIGS. 1 and 2, illustrating
principally, but not entirely, design aspects of the invention.
[0020] FIG. 4 is a right side (with reference to the blender
positioned as shown in FIG. 1) elevation of a reduced size
gravimetric blender illustrated in FIGS. 1, 2 and 3, illustrating
principally, but not entirely, design aspects of the invention.
[0021] FIG. 5 is a bottom view of a reduced size gravimetric
blender illustrated in FIGS. 1, 2, 3 and 4, illustrating
principally, but not entirely, design aspects of the invention.
[0022] FIG. 6 is a top elevation of a reduced size gravimetric
blender illustrated in FIGS. 1, 2, 3, 4 and 5, illustrating
principally, but not entirely, design aspects of the invention.
[0023] FIG. 7 is a top elevation of a reduced size gravimetric
blender illustrated in FIGS. 1, 2, 3, 4, 5 and 6, but with the top
of the hopper open, illustrating principally, but not entirely,
design aspects of the invention.
[0024] FIG. 8 is a front elevation of a reduced size gravimetric
blender shown in FIGS. 1 through 7, but with the hopper removed,
illustrating principally, but not exclusively, design aspects of
the invention.
[0025] FIG. 9 is a rear elevation of a reduced size gravimetric
blender shown in FIGS. 1 through 8, but with the hopper removed,
illustrating principally, but not exclusively, design aspects of
the invention.
[0026] FIG. 10 is a left side elevation (with reference to the
blender positioned as shown in FIG. 8) of a reduced size
gravimetric blender shown in FIGS. 1 through 9, but with the hopper
removed, illustrating principally, but not exclusively, design
aspects of the invention.
[0027] FIG. 11 is a right side elevation of a reduced size
gravimetric blender shown in FIGS. 1 through 10, but with the
hopper removed, illustrating principally, but not exclusively,
design aspects of the invention.
[0028] FIG. 12 is a top view of a reduced size gravimetric blender
shown in FIGS. 1 through 11, but with the hopper removed,
illustrating principally, but not exclusively, design aspects of
the invention.
[0029] FIG. 13 is a front elevation of the reduced size gravimetric
blender illustrated in FIGS. 1 through 12, with the hoppers in
place.
[0030] FIG. 14 is a top view of the reduced size gravimetric
blender illustrated in FIGS. 1 through 13, with the hoppers in
place and the cover removed from the hoppers.
[0031] FIG. 15 is a top view of one of the hoppers of the reduced
size gravimetric blender illustrated in FIGS. 1 through 14 with the
cover removed.
[0032] FIG. 16 is a side sectional view taken at arrows 16-16 in
FIG. 15 of the hopper illustrated in FIG. 15 showing the valve and
the hopper in an open position.
[0033] FIG. 17 is a sectional view similar to FIG. 16 showing the
valve and the hopper in a closed position.
[0034] FIG. 18 is a side elevation of a movable tubular portion of
a valve for pulsing, controlled feeding operation which resides
within a hopper such as illustrated in FIGS. 15 through 17.
[0035] FIG. 19 is a front elevation of the structure illustrated in
FIG. 18.
[0036] FIG. 20 is a view of a valve holder base part used at the
bottom of a hopper such as illustrated in FIGS. 15, 16 and 17.
[0037] FIG. 21 is a front view of the valve holder base part
illustrated in FIG. 20.
[0038] FIG. 22. is a side view of the valve holder base part
illustrated in FIG. 20.
[0039] FIG. 23 is a front elevation of a valve skirt which fits
within a hopper such as illustrated in FIGS. 15 through 17.
[0040] FIG. 24 is a top view of the valve skirt illustrated in FIG.
23.
[0041] FIG. 25 is a side elevation of the valve skirt illustrated
in FIGS. 23 and 24.
[0042] FIG. 26 is a side elevation of a movable tubular portion of
a valve for on-off, shut-off operation, which resides within a
hopper such as illustrated in FIGS. 15 through 17.
[0043] FIG. 27 is a front view of the movable tubular portion
illustrated in FIG. 26 of a valve which resides within a hopper
such as illustrated in FIGS. 15 through 17.
[0044] FIG. 28 is a top view of the movable tubular portion
illustrated in FIGS. 26 and 27 of a valve which resides within a
hopper such as illustrated in FIGS. 15 through 17.
[0045] FIG. 29 is a front view of the female member of a coupling
between the reciprocating rotating pneumatic drive and the
agitator.
[0046] FIG. 30 is a side sectional view of the structure
illustrated in FIG. 29.
[0047] FIG. 31 is a side view of a male portion of the coupling
apparatus for the agitator and the pneumatic drive apparatus.
[0048] FIG. 32 is a front view of the structure illustrated in FIG.
31.
[0049] FIG. 33 is a front elevation of the agitator.
[0050] FIG. 34 is a side elevation of the agitator shown in FIG.
33.
[0051] FIG. 35 is a front view of the liner for the mix
chamber.
[0052] FIG. 36 is a top view of the liner for the mix -chamber
illustrated in FIG. 35.
[0053] FIG. 37 is a front view of the weigh bin dump flap.
[0054] FIG. 38 is a side view of the weigh bin dump flap
illustrated in FIG. 37.
[0055] FIG. 39 is a front elevation of the stationary weigh bin
basket portion.
[0056] FIG. 40 is a right side elevation of the structure
illustrated in FIG. 39.
DESCRIPTION OF THE PREFERRED EMBODIMENTS AND BEST MODE KNOWN FOR
PRACTICING THE INVENTION
[0057] Referring to the drawings and to FIG. 13 in particular, a
gravimetric blender is designated generally 10 and includes a
hopper assembly 11 including a plurality of hoppers, which are
individually designated generally 12. The collection of hoppers 12,
each of which is individually removable from blender 10 manually,
without the use of tools, is supported by a frame designated
generally 14 which holds a weigh bin 15 into which portions of
solid plastic resin or other granular or powdery material can be
metered and-weighed prior to release into a mix chamber as
described below.
[0058] Frame 14 preferably includes four upstanding side panel
members, three of which are preferably steel and formed from a
single sheet, bent to form the three sides, with each of the three
sides being identified 30. The remaining front side panel of frame
14, which is removable and detachable from sides 30, is designated
17 in the drawings and is preferably clear, transparent
plastic.
[0059] Hopper assembly 11 with the desirable plurality of hoppers
12 allows a plurality of different solid resinous materials to be
dispensed from the hoppers 12 into weigh bin 15 by suitable valve
mechanisms, designated generally 19, located within and proximate
to the bottom of a given hopper 12. The hoppers 12 are individually
manually mountable on and removable from gravimetric blender 10 by
hand, without use of tools.
[0060] The upper extremity of each solid side panel 30 of frame 14
is formed into an outwardly flared guide flap 34. In the preferred
configuration since there are three solid side panels 30, three
outwardly flared guide flaps 34 result. Outwardly flared guide
flaps 34 are integral with and formed as a part of solid side
panels 30 by bending the upper extremities of solid side panels
into the shape illustrated in the drawings, particularly in FIG.
13.
[0061] A fourth outwardly flared guide flap 34A is positioned above
transparent removable front panel 17 and is welded to the upper
extremities of the two solid side panels 30 between which
transparent removable front panel 17 fits.
[0062] Outwardly flared guide flaps 34 preferably include tab
members 36 which are perpendicular to the remaining portion of
guide flap 34 and extend therefrom in a generally downwardly
direction. This provides a convenient hand-hold for an operator
while lifting a hopper 12 from blender 10.
[0063] Guide flaps 34 have vertical slots formed therein at the
central portions thereof with the slots extending from a lower
extremity of guide flap 34 upwardly but not to the juncture of the
upper edge of guide flap 34 with tab 36. These slots retain a
cross-frame 21 which consists of two inter-engaging members. One of
these members, which extends parallel to transparent removable
front panel 17, is indicated 21A in the drawings; the other member
is indicated as 21 in the drawing, particularly FIG. 13.
[0064] Cross-members 21, 21A have slots formed at the central
portions thereof, with one member having an upwardly facing slot
and the other member having a downwardly facing slot for engagement
one with another. Hence, when cross-members 21, 21A are resident in
the vertical slots in outwardly flared guide flaps 34, a
cross-frame defined by cross-members 21 is fixed in position
relative to frame 14 for supporting hoppers 12 in position.
[0065] Cross-members 21 are notched with the notches formed in the
lower surface thereof, to engage the unnumbered vertical slots in
outwardly flared guide flaps 34. Engagement of the notches in the
lower portions of cross-members 21 with these upwardly extending
slots and the angular orientation of outwardly flared guide flaps
34 securely retains the cross-frame defined by cross-members 21 in
place.
[0066] Hoppers 12 are easily individually manually lowered into
position in cross-frame 21 and are easily manually lifted out
thereof.
[0067] Gravimetric blender 10 further includes pneumatically
actuated spring-loaded piston means housed within cylinders which
are wholly within hoppers 12. The piston-cylinder combinations,
which are designated generally 18 in the drawings, are indirectly
fixedly connected to hoppers 12 via skirts 38. Pistons of the
piston-cylinder combinations 18 are preferably spring-loaded and
operate in response to pressurized air to actuate tubular valve
members housed within skirts 38. When the pistons move the tubular
valve members housed within skirts 38, in a direction indicated by
arrow A in FIGS. 16 and 17, a given piston moves a given associated
valve member vertically downwardly into the position illustrated in
FIG. 16, discharging granular material contained within the
associated hopper 12 downwardly into the weigh bin of the
blender.
[0068] When pneumatic pressure supplied to a given piston is
released, an internal spring portion of the piston-cylinder
combination causes the piston to retract, thereby retracting the
valve member in a vertically upward direction, into the position
illustrated in FIG. 17, at which the valve is closed and granular
material cannot flow downwardly from hopper 12 into the weigh bin
15.
[0069] The valve members are designated generally 19 in the
drawings. Each valve member includes a tubular, preferably
cylindrically configured stem member designated generally 40 and
illustrated in FIGS. 26, 27 and 28.
[0070] Tubular stem member is connected to a movable piston portion
of piston-cylinder combination 18 via a piston shaft 42 as
illustrated in FIG. 16. Preferably piston shaft 42 does not
directly connect with tubular stem member 40 but rather has a yoke
or clevis 44 connected to the end of piston shaft 42 which is
remote from piston-cylinder combination 18. Yoke 44 includes a pair
of arms 46 extending from a body portion of yoke 44 in the manner
illustrated in FIG. 16. Yoke arms 46 are bored with the bores
through parallel yoke arms 46 being transverse thereto and parallel
one with another.
[0071] A pin 48 connects yoke 44 with tubular stem member 40 by
passing through the parallel bores in yoke arms 46 and through an
aperture 50 in tubular stem member 40. Pin 48 fits slidably in
aperture 50 and the bores in yoke arms 46.
[0072] Tubular stem member 40 is housed within a skirt designated
generally 38 in the, drawings and illustrated in stand-alone form
in FIGS. 24, 25 and 26. Skirt 38 is of generally rectangular
configuration, as illustrated in FIG. 24, and has two adjoining
closed sides 52, 54 and two non-adjoining open sides 56, 58, all as
illustrated in FIG. 24. Open sides 56, 58 of skirt 38 include
holes, which have not been numbered in the drawings, via which
suitable sheet metal screws or other fasteners secure open sides 56
and 58 and therefore skirt 38 to adjoining vertically-oriented
walls 60, 62 of a hopper 12. Walls 60, 62 adjoin one another at a
right angle and are as illustrated in FIG. 15. One such sheet metal
screw, which has been designated 64, is illustrated in FIG. 15
securing an open side 56 of skirt 38 to vertical wall 62 of hopper
12.
[0073] Skirt 38 further includes a closed top portion 66 having an
aperture 68 formed therein. Piston-cylinder combination 18 is
secured in place on closed top 66 of skirt 38 and passes through
aperture 68 with securement being effectuated by a nut 70 which
threadedly engages a threaded portion of the housing of
piston-cylinder combination, retaining the piston-cylinder
combination in position on closed top 66 of skirt 38 as illustrated
in FIGS. 16 and 17.
[0074] Skirt 38 is preferably formed by folding a single piece of
sheet metal into the shape of closed sides 52, 54 and open sides
56, 58. Closed top 66 is preferably welded onto the single piece of
metal folded to form closed sides 52, 54 and open sides 56, 58 of
skirt 38.
[0075] Further forming a portion of each valve assembly 19 in each
hopper 12 is a valve holder base illustrated in FIGS. 20, 21 and 22
and shown in position within hopper 12 in FIGS. 15, 16 and 17. The
valve holder base is designated generally 72 and is preferably
fabricated from a single piece of sheet metal. Valve holder base 72
includes a flat, horizontally disposed planar portion 74 and a pair
of upstanding side walls 76, 78.
[0076] Within planar portion 74 is an aperture 80 which is of
suitable size for sliding clearance of the lower portion of tubular
stem member 40, which resides within and reciprocates along
aperture 80 in planar portion 74 as illustrated in FIGS. 16 and
17.
[0077] Side walls 76, 78 include holes formed therein to receive
sheet metal screws 64 which retain valve holder base in position at
the bottom of hopper 12 by passage through hopper vertical walls
60, 62. One of sheet metal screws 64 is illustrated in FIG. 17
retaining valve holder base in position within hopper 12.
[0078] The configuration of valve holder base 72 and the diameter
of aperture 80 vis-a-vis the outer diameter of tubular stem member
40 are-such that granular or other material contained within hopper
12 cannot pass between the exterior of tubular stem member 40 and
the periphery of aperture 80. Additionally, other than aperture 80,
valve holder base 72 and particularly planar portion 74 thereof
close off the bottom of hopper 40. As a result, for any granular
material contained within hopper 40 to exit downwardly therefrom,
that granular material must pass through the hollow interior of
tubular stem member 40.
[0079] The two closed sides 52, 54 of skirt 38 have rectangular
cut-outs formed therein at the lower extremities thereof. One of
these cut-outs formed in the lower portion of closed side 52 is
designated 82 in FIG. 23. Since cut-outs 82 are formed in the lower
portions of closed sides 52, 54 of skirt 38, and since closed sides
52, 54 of skirt 38 are not in facing contact with vertical walls
60, 62 of hopper 12, the two communicating rectangular cut-outs 82
form an open notch 84 in skirt 38 at the lower extremity thereof,
facing away from the interior corner of hopper 12 defined by the
juncture of vertical sides 60, 62. Notch 84 is specifically defined
by a pair of vertical edges 86 formed respectively in closed walls
52, 54 and a horizontal edge 88 formed in closed walls 52, 54, as
illustrated in FIGS. 23 and 25.
[0080] Tubular stem member 40 also has a notch 90 formed therein.
Notch 90 is defined by a pair of semi-circular edges 92 and a pair
of vertically extending edges 94 connecting edges 92 thereby to
define a semi-cylindrical notch 90.
[0081] As illustrated in FIGS. 16 and 17 showing the valve-assembly
19 in hopper 12 in the open and closed positions respectively, at
the open position the piston in piston-cylinder combination 18 is
extended such that piston rod 42 is vertically extended downwardly
and notch 90 in tubular stem member 40 is in facing communication
with notch 84 in skirt 38. With tubular stem member 40 in this
relationship with skirt 38, communication between notch 84 and
notch 90 permits flow of granular material downwardly from within
hopper 12 into the hollow interior of tubular stem 40 and
downwardly therethrough out of hopper 12. This configuration is
illustrated in FIG. 16.
[0082] When the piston in piston-cylinder combination 18 is
retracted, tubular stem member 40 is carried upwardly into a
position at which notch 90 is not in communication with notch 84.
At this position, communication from the interior of hopper 12 with
notch 90 is blocked by closed sides 52, 54 of skirt 38 as
illustrated in FIG. 17. As a result, granular material within
hopper 12 cannot reach the hollow interior of tubular stem member
40 and thus cannot flow downwardly through the hollow interior of
tubular stem member 40 out of hopper 12. Hence, the valve assembly
19 is closed when in the position illustrated in FIG. 17.
[0083] Piston-cylinder combination 18 is preferably a spring-loaded
piston-cylinder combination such that a spring within the cylinder
serves always to urge the piston portion of the combination
vertically upwardly considering FIGS. 16 and 17 into the position
at which tubular stem member 40 does not communicate with the
interior of hopper 12 and hence valve assembly 19 is closed.
Application of pneumatic pressure to piston-cylinder combination 18
drives the piston of the combination downwardly, against the force
of the spring, thereby moving tubular stem member 40 into the
position at which the valve member 19 is open. The valve member
remains open for so long as the pneumatic pressure is applied to
piston-cylinder combination 18. When the pneumatic pressure is
released, the spring forces the piston vertically upwardly in FIGS.
16 and 17, thereby closing valve member 19.
[0084] An important aspect of the invention is the feature whereby
the valve members designated generally 19 are entirely contained
within hoppers 12 and are fixedly secured thereto. As a result,
when an operator desires to change a hopper, all that is required
is for the operator to disconnect a pneumatic tube from a pneumatic
fitting 96 on a given hopper and lift the hopper off of the
supporting cross and outwardly flared guide flaps 34 on which the
hopper rests. Note that hoppers 12 are not mechanically secured to
the remainder of blender 10; this is not necessary. The external
pneumatic fitting for each hopper is designated 96 and illustrated
in FIG. 13. A pneumatic line 98 leads from fitting 96 to the
piston-cylinder combination 18 within each hopper 12; this is
illustrated in FIG. 14.
[0085] One of the important features of this invention is the
compact size of the gravimetric blender. The compact size of this
blender facilitates use of this blender with very small injection
molding and compression molding machines and with small extruders.
The small size of the blender in the preferred embodiment of the
invention facilitates dispensing of exceedingly small and precisely
measured amounts of plastic resin material and other granular
materials, as well as liquid color if that might be desired as a
part of the blend, for supplying such small molding machines and
extruders.
[0086] In the preferred embodiment of the invention, hoppers 12 are
eight inches square at the upper extremities thereof; this is
denoted by dimension A in FIG. 14. The close spacing together of
adjacent hoppers, with adjacent hoppers being only about one-eighth
inch apart, which is the thickness of the cross-members defining
cross-frame 21, results in an overall maximum width dimension
indicated as B in FIG. 14 of about sixteen and one-eighth inches in
the preferred embodiment of the invention.
[0087] Similarly, the blender in the preferred embodiment of the
invention is very compact in height. In the preferred embodiment,
the blender is only about twenty-two inches from the top of the
hoppers to a base portion of the blender frame. This twenty-two
inch dimension is indicated by dimensional arrow C in FIG. 13. The
pneumatic piston which preferably actuates the weigh bin to dump
the weigh bin contents into the mixing chamber is preferably about
eleven and five-eighth inches above the base; this dimension is
indicated by dimensional arrow D in FIG. 13.
[0088] With this arrangement of hoppers 12 as illustrated generally
in FIGS. 13 and 14, the blender of the invention may be operated
with only a single hopper in place or with two or with three or all
four hoppers in place. Absence of one hopper or more than one
hopper does not adversely affect operation.
[0089] Depending on the particular material being fed and blended,
piston-cylinder combinations 18 may be operated to open and to
close valve members 19, i.e. to move valve members 19 between open
and closed positions. Alternatively, if it is desired to very
precisely regulate the amount of granular material supplied from a
given hopper 12, piston-cylinder combination 18 may be operated in
a pulsating fashion with the piston rapidly reciprocating as pulses
of pneumatic pressure are alternately applied and relieved
respecting the piston of piston-cylinder combination via pneumatic
fitting 96.
[0090] FIGS. 18 and 19 illustrate an alternate embodiment of the
tubular stem member which has been designated 40A in FIGS. 18 and
19. In this embodiment, tubular stem member 40A has a blocking wall
100 positioned in notch 90 where blocking wall 100 includes a
horizontal portion 102 and a vertically extending portion 104.
Horizontal portion 102 runs along and is secured to a lower one of
semi-circular edges 92 while vertical portion 104 extends
vertically upwardly therefrom and runs along and is connected to
vertical edges 94 up to approximately the vertical midpoints
thereof, as illustrated in FIG. 19. An outwardly angled lip, of
generally curved configuration, designated 106 in FIGS. 18 and 19
may be optionally provided at the upper extremity of vertical
portion 104; the optional character of outwardly angled lip is
denoted by the dotted lines in which it is shown in the
drawings.
[0091] With this configuration of the blocking wall 100 in place on
tubular stem member 40A, when the associated piston-cylinder
combination is operated in a pulsed, fashion, the rate of
dispensing of granular material from the associated hopper may be
extremely closely controlled.
[0092] Positioned within and preferably slidably retained by frame
14 below weigh bin 15 is a mix chamber 20 having a mixing means
which is preferably in the form of a mixing agitator 22 rotatably
disposed therewithin. Agitator 22 is mounted for rotation about an
axis 24 preferably shared with a pneumatically powered
reciprocating rotary drive 26.
[0093] Weight of material in weigh bin 15 is preferably sensed by a
load cell 32 which is preferably connected to a microprocessor
control, not illustrated in the drawings, which regulates operation
of gravimetric blender 10 through electrical connection with the
load cell, the actuators which control the piston-cylinder
combinations 18 which actuate the valves 19, the pneumatic drive,
the piston-cylinder controlling weigh bin dump and the like.
[0094] The microprocessor provides control of gravimetric blender
10 by monitoring, preferably on a continuous basis, weight of
material, if any, at a weighing station defined by weigh bin 15. By
sensing weight of weigh bin 15 and actuating appropriate
piston-cylinder combinations 18 in given hoppers 14, the
microprocessor serially meters respective components of solid
granular resinous material to the weighing station defined by weigh
bin 15 until a pre-selected weight of each of the respective
components has arrived at the weigh station.
[0095] Blender 10 preferably operates by blending components by
weight based on settings provided to and retained within the
microprocessor.
[0096] Each granular material component is preferably dispensed
separately into weigh bin 15 and then all components are dropped
together into mixing chamber 20.
[0097] Blender 10 is designed to mount directly over the feed
throat of a process machine used to mold or extrude plastic
material with blender 10 being bolted or otherwise fixedly
connected to the process machine.
[0098] When exclusively solid materials are being blended,
typically regrind material is dispensed first according to the
percent of regrind material required. If no regrind material or a
limited amount of regrind material is present, then portions of
natural material, solid color material and additive material are
increased to bring about a full batch weight. Natural material is
typically added second. The amount of natural material added is
preferably calculated by the microprocessor to leave exactly the
right amount of room in the mix chamber for the solid color
material and additive material. Once the natural material fill
portion of the cycle has been completed, the exact weight of the
natural material that has been actually dispensed is determined to
detect any errors. Based on this actual weight of natural material
dispensed, color additive in the form of solid color additive
material is metered into the weigh bin, then other solid additive
materials are metered into the weigh bin in the same manner. All
components are then dumped into the mixing chamber which is
preferably continuously running.
[0099] In the case where liquid color material is used in place of
solid color material, the liquid color material is preferably added
to the weigh bin last.
[0100] The microprocessor provides the serially metered components
and the optional preselected weight of liquid color material
unitarily to a mixing station defined by mix chamber 20 by opening
weigh bin 15 thereby to permit the materials vertically supported
thereby to fall downwardly into the mix chamber. Weigh bin 15 is
preferably opened by a pneumatic piston-cylinder combination 136,
which is controlled by the microprocessor and is illustrated FIG.
13. Pneumatic piston-cylinder combination 136 is mounted on frame
14 and is proximate to, but not in contact with, weigh bin 15 so
that weigh bin 15 opens responsively to movement of the piston
member of the piston-cylinder combination.
[0101] Weigh bin 15 is illustrated in FIG. 13 in solid lines in the
closed position. Weigh bin 15 is opened by actuating
piston-cylinder combination 136, causing a piston rod to
extend.
[0102] When weigh bin 15 is in the closed position, there is no
contact nor connection with the piston or its actuating
cylinder.
[0103] In mix chamber 20 the solid material components which have
been preferably unitarily supplied and serially metered to weigh
bin 15, and optionally a pre-selected weight of liquid color
material, are mixed into a blend preparatory to being supplied to
the manufacturing processing machine such as a molding press or an
extrusion machine.
[0104] Desirably, monitoring of weight of material at the weighing
station is performed continuously by the microprocessor
continuously digitally sensing signals supplied by the load cell
identified generally 32. Weigh bin 15 is suspended by and from load
cell 32 with respect to frame 14.
[0105] The microprocessor actuates to dispense material as
required.
[0106] The solenoid valves and especially the solenoid actuators of
the valves are preferably maintained within an enclosed frame which
is remote from the blender and hence is not shown in the drawings.
As with the microprocessor, the valves and their associated
actuators are preferably remote from the gravimetric blender, being
connected thereto via suitable pneumatic tubing.
[0107] Vertically extending extremities may provide an open
envelope structure which permits weigh bin 15 and particularly a
weigh bin bracket to move slidably horizontally, in a direction
perpendicular to the plane of the paper in FIG. 13, to be
positioned so that weigh bin 15 effectively hangs on and is
cantilevered from load cell 32.
[0108] Affixed to load cell 32 for receiving the weight load and
transferring the same to load cell 32 is a load transfer beam
having an upper horizontally extending portion fixedly connected by
a screw to the upper surface of load cell 32, a lower generally
horizontally extending portion and a central portion extending
between upper and lower portions and being slightly canted from the
vertical. Load cell 32 senses the weight load of weigh bin 15 and
any material contained therein by strain resulting at the upper
surface of load cell 32 where the load transfer beam is fixedly
connected thereto. Load cell 32 is fixed to a load cell enclosure
box, particularly to a lower horizontally extending portion of the
load cell enclosure box via suitable screws.
[0109] Affixed to a central portion of a load transfer beam is a
load transfer plate which is preferably slotted at the central
portion thereof with the slot being relatively short, preferably
being only about 1 inch in length, to receive a screw which extends
laterally from vertical portion of a weigh bin bracket, as weigh
bin 15 is slidably positioned on and supported by a load transfer
plate. In this position weigh bin 15 may be effectively
cantilevered with respect to load cell 32 and the load represented
by the weight of the weigh bin 15 and any material contained
therein is transferred directly to load cell 32 by the load
transfer plate and load transfer beam, with load cell 32
effectively sensing the weight of material contained within bin
15.
[0110] To protect load cell 32 from contact and possible damage by
operators, load cell 32 is preferably within a load cell enclosure
box as illustrated in FIG. 13. The load cell enclosure box is in
turn preferably connected to a load cell mounting plate by suitable
nut and bolt combinations. The nut and bolt combinations are spaced
away from and do not contact frame 14.
[0111] Load cell 32 is fixedly connected to the bottom of the load
cell enclosure box via screw connectors which rigidly hold the load
cell in position vis-a-vis the load cell enclosure box. Hence the
bottom of the load cell is fixed whereas the upper portion of the
load cell, where the load is sensed, is free to deflect in response
to loads applied as result of material being in the weigh bin.
[0112] Suitable load cells are available from Tedea Huntleigh, an
Israeli company. Model 1010 load cells available from Tedea
Huntleigh may be used.
[0113] Solenoid actuated valves are available in the United States
under the trademark MAC; the model 45A-L00-DDAA-1BA9 is
suitable.
[0114] Weigh bin 15 includes a stationary open bottomed basket
portion 108 illustrated in FIGS. 39 and 40 where basket portion 108
is also visible in FIG. 13. Basket portion 108 is preferably formed
of sheet metal in the manner shown generally in FIG. 39 with planar
front and rear portions designated 110, 112 in FIGS. 39 and 40. The
top of basket 108 is open to receive granular material, and
optionally liquid color, from above, with the granular material
being supplied from one or more of hoppers 12.
[0115] Basket 108 further includes one vertically elongated side
114 at one side of basket 108 and a vertically foreshortened side
116 at the other side of basket 108.
[0116] Basket 108 further includes a sloped downwardly facing
surface 118. The bottom of basket 108, designated 120 in FIGS. 39
and 40, is open to permit downward flow of granular and,
optionally, liquid color material, out of basket 108.
[0117] Weigh bin 15 further includes a dump flap designated
generally 120 in the drawings which is pivotally connected to
basket portion 108 so that upon pivotal motion of dump flap 120,
the contents of basket 108 are dropped out of weigh bin 15 and
permitted to fall into mix chamber 20. Dump flap 120 is illustrated
in FIGS. 37 and 38 and is also clearly visible in FIG. 13.
[0118] Dump flap 120 includes a pair of upstanding wall portions
122, 124, both of which extend generally vertically upwardly from a
planar bottom portion 126. Dump flap 120 further includes an angled
bottom portion 128 which is positioned at an angle to essentially
complementally fit against sloped downwardly facing surface 118 of
basket 108, as shown in FIG. 13.
[0119] Upstanding walls 122, 124 of dump flap 120 have apertures
130 formed therein on a common horizontal axis. Apertures 130
receive pin, screw or other pivotal connection means for pivotally
connecting dump flap 120 to basket 108 through similar apertures
132 formed in sides 110, 112 of basket 108.
[0120] Affixed to a vertical extremity of an upstanding extension
portion of upstanding wall 124 of dump flap 120 is a flat head
rivet 134, which is preferably welded in position.
[0121] Mounted in one of solid side panels 30 of frame 14,
specifically the right hand solid side panel 30 as illustrated in
FIG. 13, is a piston-cylinder combination designated generally 136
in FIG. 13. Piston-cylinder combination 136 is preferably mounted
using a suitably threaded nut, illustrated in FIG. 13 but not
numbered, which engages a threaded collar portion of
piston-cylinder combination 136 protruding through an aperture of
suitable size in side panel 30.
[0122] Affixed to the end of a piston rod extending from
piston-cylinder combination 136 is a preferably plastic, such as
nylon, knob 138 illustrated in FIG. 13.
[0123] When material within weigh bin 15 is to be dumped,
piston-cylinder combination 136 is actuated by supply of pressured
air thereto. This causes the piston portion of piston-cylinder
combination 136 to extend, moving to the left in FIG. 13. As a
result, knob 138 contacts the flat head rivet 134 which is fixed in
the upper extremity of vertical side wall 130 of dump flap 120
thereby causing dump flap 120 to pivot in a counterclockwise
direction, viewed in FIG. 13, about a pivot point defined by
pivotal connections mounted in apertures 130 illustrated in FIG.
13.
[0124] This pivotal, rotary motion of dump flap 120 in a
counterclockwise direction (considering FIG. 13) about pivot point
130 opens the bottom of basket 108 permitting material contained
within the weigh bin defined by dump flap 120 and basket 108 to
drop into the mixing chamber.
[0125] Note that knob 138 only contacts flat head rivet 134 when
piston-cylinder combination 136 has been actuated and the dumping
operation is taking place. At all other times, there is no physical
contact between weigh bin 15 and knob 138. A spring 190 biases dump
flap 120 towards the closed position.
[0126] Weigh bin 15 is connected to load cell 32 through an
aperture in solid side panel 30 of frame 14, specifically the
left-hand one of solid side panels 30 considering FIG. 13, by a
slide mount bracket 140 which is bolted to load cell 32 and extends
laterally and then upwardly to fit within a downwardly facing lip
142 formed at an upper extremity of vertically elongated side 114
of basket 108, as illustrated in FIG. 39. Hence, basket 108 and
therefore weigh bin 15 effectively hang from load cell 32 so that
load cell 32 senses the weight of weigh bin 15 and any granular
and, optionally, liquid color, material contained within the weigh
bin.
[0127] Other suitable means for mounting weigh bin 15 respecting
load cell 32 are disclosed in pending U.S. patent application Ser.
No. 08/763,053, filed in the name of Stephen B. Maguire on Dec. 10,
1996, and pending Patent Cooperation Treaty patent application
PCT/US96/19485, filed Dec. 10, 1996 by Maguire Products, Inc., the
disclosures of which are incorporated as reference.
[0128] Mixing agitator 22 is rotatably journeled in preferably
transparent, removable front panel 17 of frame 14. Panel 17 fits
closely along forwardly facing edges of solid side panels 30 and is
fixed thereto via quick release, hand-actuated clips designated
generally 144 in FIG. 13. These clips are mountingly connected to a
horizontal bar 146 extending across front panel 17 at a lower
portion thereof, which provides a solid, preferably metal
receptacle mounting for journeling of agitator 22 in transparent
removable front panel 17.
[0129] Fixed rotatable journeling of agitator 22 in transparent
removable front panel 17 provides an important safety feature. If
an operator removes front panel 17 by disengaging clips 144,
agitator 22 remains fixed to front panel 17 and disengages from the
rotary reciprocating drive means, discussed below, and is removed
from the mix chamber 20 whenever front panel 17 is removed from
blender 10. This provides an important safety advantage in that
agitator 22 ceases rotation as panel 17 is moved even slightly away
from contact with solid side panels 30. Hence, if an operator
reaches inside blender 10, there are no moving parts to inflict
injury when front panel 17 has been removed.
[0130] As illustrated in FIGS. 33 and 34, agitator 22 includes a
central shaft portion 146 with a number of spokes 148 extending
radially outwardly therefrom. Extending longitudinally along the
outer extremities of radial spokes 148 are mixer rails 150 which
extend longitudinally along a major length of central shaft 146 and
are curved radially inwardly at the ends of rails 150 which are
remote from front panel 17 when the agitator is journeled in panel
17.
[0131] Journeling of central shaft 146 in front panel 17 is
accomplished using a plastic, preferably Nylon or Celcon,
cylindrical bearing member 152 illustrated in FIG. 13. The left end
of shaft 146 (when considering FIG. 34) fits into bearing member
152. Mixer rails 150 and particularly the curved, radially inwardly
facing extremities thereof 151 stop short of center shaft 136 in
order to provide clearance for a coupling member which removably
connects the agitator 22 to the rotary reciprocating drive
means.
[0132] To facilitate removal of front panel 17 from blender 10, and
to provide strength for journeling of bearing member 152 in front
panel 17, a metal plate or strap 154 is affixed to front panel 17
and provides a position of attachment for clips 144. A handle 156
is mounted on strap 154 and provides convenient hand gripping for
removal of front panel 17 when clips 144 have been disengaged.
[0133] Agitator 22 is driven in a manner to reciprocatingly rotate
so that agitator 22 rotates about axis 24 defined by central shaft
146 through an angle of about 270.degree. and then reverses,
rotating in the opposite direction thorough an angle of about
270.degree.. This is accomplished by using a drive consisting of
two pneumatically driven piston-cylinder combinations reciprocating
a rack to which a pinion gear is connected. This drive means is a
purchased item and is mounted on the exterior of a rear panel 30 of
frame 14 in position to provide coaxial driving rotation of
agitator 22.
[0134] Means for coupling and decoupling agitator 22 to the
reciprocating rotational drive means is provided by a coupling
assembly having male and female members which are illustrated
generally in FIGS. 29 through 32.
[0135] The smaller of the two members forming the coupling is
designated generally 158 and is illustrated in FIGS. 31 and 32.
This smaller member is referred to as a male member and is
generally cylindrically configured with a curved, cylindrical
exterior surface 160, an axially elongated bore 162 extending
therethrough and a transverse bore 164. Axially elongated bore 162
is of appropriate size for fitting of male member 158 on end 146R
of shaft 146 of agitator 22, as illustrated in FIG. 34. Set screws
or suitable pins in transverse bore 164 may be used to affix male
member 158 to end 146R of central shaft 146.
[0136] Formed in outer surface 160 of male member 158 are a
plurality of angularly evenly spaced flutes 166 which extend
axially respecting male member 158 and are concave, as illustrated
in FIG. 32. Concave flutes 166 are provided to receive and to fit
about pins which extend outwardly from a female member 170 as
illustrated in FIG. 29 and especially in FIG. 30, with one pin 122
being illustrated in position in FIG. 30. The longitudinal
extremity of male member 158, which faces away from agitator 22 and
towards female member 170 when male member 158 is assembled on and
affixed shaft 146, is chamfered with such chamfers indicated as 168
in FIG. 31. These chamfers facilitate engagement of male member 158
generally and specifically of flutes 166 with pin members 172 of
female member 170, so that the pin members may reside within flutes
166 in essentially complemental, facing contact. Male member 158 is
preferably plastic, most preferably Celcon or Nylon.
[0137] Female member 170 illustrated in FIGS. 29 and 30 is of
generally cylindrical configuration, with an annular shoulder 174
defining a stepdown from a larger cylindrical diameter to a smaller
cylindrical diameter. The end of female member 170 of smaller
cylindrical diameter is the end which is closer to the source of
reciprocating rotational movement and is journaled in a rear solid
panel 30 of frame 14, in a position of axial alignment with bearing
member 152 when transparent removable front panel 17 is in position
as a part of frame 14.
[0138] Female member 170 further includes a longitudinal bore 176
extending the longitudinal length thereof with a keyway 178 formed
in bore 176. Keyway 178 is provided for fitting about a driving
shaft providing the source of reciprocating rotational movement for
agitator 22.
[0139] A pair of radial bores 180 are provided in the larger
cylindrical sectional portion of female member 170 for set screws
or other pin connections to tightly retain female member 170 on the
drive shaft coming from the source of reciprocating rotational
motion.
[0140] As can readily be envisioned by comparing FIGS. 30 and 32,
pins 172 fit within flutes 166 and easily find those flutes 166
when the front panel 17 is put into position and the male member
158 fixedly connected to shaft 146 is pushed towards female member
170 and especially pins 172. Chamfer surfaces 168 on male member
158 facilitate pins 172 finding flutes 166 and moving into
complemental, facing engagement therewith. Once this has been
accomplished, driving rotation of female member 170 by the
reciprocating rotational drive means results in corresponding
one-to-one rotation of male member 158 and consequent rotation of
agitator 22.
[0141] One of the important features of the invention is that the
integral construction of the valve and hopper assembly permits the
valve to be removable integrally with the hopper, thereby
permitting various size valves to be mounted in hoppers. This
facilitates changing of valve size by the user so that the user
merely need remove the hopper having a given size valve and
substitute another hopper having a smaller or other desired size
valve in its place. The integral valve-hopper design also
contributes to safety in that individuals cannot actuate a valve
and injure themselves when a hopper is removed from the blender.
The valve and the shut-off mechanism for granular material simply
is not present when the hopper is not in place. Once the hopper is
in position, an individual cannot insert the individual's fingers
into the way of any of the moving parts of the valve within the
hopper.
[0142] The air cylinders actuating the valves are preferably spring
return air cylinders; internal springs act to pull the cylinder
pistons up and pull the rods attached to the pistons into the
vertical position, creating a shut-off. When the tubular members 40
are in the extreme vertically upward positions, no material can
flow downwardly therethrough; the hopper is necessarily closed at
the bottom and can easily be removed without spilling any material
that may be in the hopper.
[0143] In the variation of this valve which is illustrated in FIGS.
18 and 19, where the hemispheric or half-circular opening in a
tubular portion is covered at the bottom and has a wall running
upwardly, this tubular valve member 40A may be reciprocated up and
down to provide very accurate downward metering of material. When
such accurate metering of material is desired, a stroke limiter in
the form of a sleeve of plastic may be used on the rod 42 which
connects the associated piston to the yoke 44.
[0144] The piston-cylinder combination 18 is desirably reciprocated
electronically, permitting the piston to cycle up to six times per
second providing the reciprocation of the tubular stem member 40A.
Skirt 38 is stationary, fitting around the reciprocating tubular
stem member 40A, skirt 38 is secured to hopper 12 by sheet metal
screws going through the hopper into the skirt. The skirt is
stationary when the valve is in the hopper and shields the tubular
stem member 40 as tubular stem member 40 moves up and down. Skirt
38 allows granular material to enter tubular stem member 40 only
when tubular stem member 40 and particularly the aperture 50
therein is below the upper extremity of the horizontal edge 88
defining the upper boundary of notch 84.
[0145] Skirt 38 is preferably a single piece of sheet metal having
two full-size or closed sides and two shortened or flanged or open
sides facing the two surfaces or walls of hopper 12 to provide
complete closure around tubular stem member 40.
[0146] One pneumatic line preferably goes to each hopper 12 with a
quick disconnect fitting to allow the hopper to be removed from the
blender. Air is pulsed back and forth by solenoid valves. Since the
piston-cylinder combinations have spring return pistons, only one
line is needed to each piston-cylinder combination. This is in
contrast to prior art gravimetric blenders in which two lines are
provided to piston-cylinder combinations driving the various slide
gates and other parts of the machine.
[0147] In the instant invention, the pneumatic supply line goes
through the side of each hopper 12 and connects to the
piston-cylinder combination within the hopper. Removal of the
hopper and piston-cylinder combination is facilitated by
disconnecting the pneumatic line at the quick disconnect fitting 96
provided on the exterior of each hopper 12 and picking off each
hopper 12 and its associated piston-cylinder assembly 18 which is
one effectively unitary assembly and may be lifted directly off of
the top of blender 10.
[0148] Another important aspect of the invention is in the
provision of the separation of knob 138 from flat head rivet 134
for opening the dump flap 120 of weigh bin 15. With piston-cylinder
combination 136 and knob 138 physically separated from weigh bin
15, there is no external connection to weigh bin 15 during the
weighing process and therefore, there is no chance of something
such as a pneumatic line introducing an error into the weighing
procedure.
[0149] Respecting mixing chamber 20, mixing chamber 20 is equipped
with a curved side and bottom member which slides into an out of
the mixing chamber. This curved member is visible in FIG. 13, is
illustrated separately in FIGS. 35 and 36 and is designated
generally 182 in the drawings and sometimes referred to as a mix
chamber insert slide. Insert slide 132 rests on a plastic saddle
184 which is visible in FIG. 13. Saddle 184 is secured to the metal
bottom 186 of frame 14. Solid side panels 30 of frame 14 are
preferably welded to bottom 186 along the three sides of respective
contact therewith. Bottom 186 preferably protrudes forwardly
relative to sides 30 so as to provide a bottom support transom for
transparent removable front panel 17 when panel 17 is in place on
blender 10.
[0150] The reciprocating rotational motion provided by the drive
unit rotates agitator 22 approximately 270.degree. in one direction
and then 270.degree. in the opposite direction.
[0151] One advantage of the coupling defined by male and female
members 158, 170 with the pins 172 of female member 170 engaging
the flutes 166 of male member 158 is that there are no closed
bottom holes into which pins 172 must fit. With an "open" coupling
such as provided by male and female members 158, 170, there is less
likelihood of catching pellets of the granular material in the
coupling itself.
[0152] Yet another feature of the invention is with agitator 22
being journaled within and removable unitarily with transparent
removable front panel 17, there is no need for any interlock
between front panel 17 and the drive means providing the
reciprocating rotational drive for the agitator. Since agitator 22
is removed with transparent front panel 17, whenever panel 17 is
removed, the only moving part remaining in the mixing chamber is
the rotating female member 170.
[0153] When the blender of the invention is used, there is
preferably a single controller provided for each blender at a
remote locale. The controller and microprocessor preferably are not
mounted on the frame of the blender as is the case with known,
larger gravimetric blenders.
[0154] Material components which should be fed and controlled in
very, very small amounts, such as color components, may be
controlled to levels of 3% or 4% of the total blend when the
pulsing action of a piston-cylinder combination is applied to a
modified version of the tubular stem member 40A as illustrated in
FIGS. 18 and 19. In addition to color additives, ultraviolet
stabilizers, inhibitors, strengtheners and the like sometime need
to be fed in such very, very small amounts into plastic resin
blends prior to molding.
[0155] In the blender, there is provided a proximity sensor
indicated as 188 in the drawings. This sensor fits through a rear
wall 30 of frame 14 and protects the machine by shutting off the
machine when material in the mix chamber reaches a certain level.
These proximity sensors are known in the art.
[0156] Using the modification of the tubular stem member 40
illustrated in FIGS. 18 and 19 and with pulsing action of the
spring equipped piston-cylinder combination 18 allows very fine
feeding of material. If air pressure is reduced to piston-cylinder
combination 18, so as to soften the severity of the reciprocation
of the air cylinder, the air cylinder can be regulated to a point
where as little as two to three grams of material per second can be
accurately fed and feeding can be repeatedly controlled at that
rate.
[0157] Utilizing the reduced size gravimetric blender of the
invention, batches of material of about 400 grams may be produced
with such batches being produced in less than one minute per batch.
Hence, about fifty pounds per hour of blended resin material can be
produced using the blender of the invention.
[0158] The valve members 19 with the full half-cylindrical opening
as illustrated in FIGS. 26 and 27 may dispense material at about 35
grams per second. When the pulsing technique is used and the
modified version of the tubular stem member 40A illustrated in
FIGS. 18 and 19 is used, feeding of plastic resin material pellets
can be controlled to a level down below one gram of feed per
second.
* * * * *