Dispensing – Processes of dispensing
Reexamination Certificate
1998-11-20
2001-02-13
Kashnikow, Andres (Department: 3752)
Dispensing
Processes of dispensing
C222S181200, C222S203000
Reexamination Certificate
active
06186360
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to bulk material handling and, more particularly, to apparatus for emptying portable receptacles, e.g., flaccid/limp/soft-sided bags, by “jarring” or “working” them.
BACKGROUND OF THE INVENTION
Many types of dry, finely-divided (i.e., powdered or powder-like) materials, e.g., flour, rice hulls, pharmaceuticals, plastic, colorant, cement among many, many others, are shipped to a point of usage using large, soft-sided, reusable bags. Such bags, commonly cubic, have a top fill opening and a bottom spout and after being emptied, the soft bags may be collapsed to but a fraction of their filled volume for return to a filling site.
At the point of usage, such bags are mounted one-at-a-time on a machine of the type generally known as a bag unloader or bag frame. There, the contents of the bag are emptied through the spout for, e.g., repackaging into retail containers, compacting into tablet form, mixing with other constituents or for other, further processing. A representative list of companies selling (or which have sold) bag unloading equipment includes National Bulk Equipment, Inc. (NBE), Holland, Mich.; Vac-U-Max, Belleville, N.J.; and Beta Raven, Inc. of Earth City, Mo. And Schenck AccuRate, Inc., Whitewater, Wis., is a leading manufacturer of such equipment.
A characteristic of bag-confined, finely-divided or powdered materials is that when the bag is full or nearly so and the spout is opened for material discharge, the material tends to “bridge,” i.e., to repose in an arch-like formation. While such formation is structurally quite weak, it is sufficient to impede material flow. Similarly, such materials may “rat hole,” i.e., may flow from the spout in such a way that a downwardly extending hole forms. This, too, impedes material flow.
This characteristic of dry powder materials has long been recognized and steps have been taken to prevent such bridging and rat holing. NBE uses a pair of double-faced paddles moved by a common cylinder to agitate the powder in a bag. NBE literature indicates this arrangement is to promote powder flow if bagged material becomes packed during transportation or storage. Another arrangement available from NBE involves arm-mounted hammers which periodically strike the sides of the bag.
Another aspect of prior art involves what is often referred to as a bag tensioning or bag lifting mechanism. One known type of such mechanism supports the bag using what are known as gas cylinders or, more typically, gas springs. (As an illustration, a gas spring is often used to automatically raise the rear hatch of a hatchback auto when unlatched.) The known type of mechanism uses four such gas springs.
While these prior art arrangements have been generally satisfactory for their intended purposes, they are not without disadvantages. As a general observation, such prior art arrangements seem not to optimally address the need to help assure smooth powder flow during all phases of bag emptying, i.e., at initial discharge, when the bag is about half empty and when the bag is nearly empty.
More specifically, known prior art arrangements do not optimally prevent close-to-the-spout material bridging at the onset of material flow from a fully-filled bag. Nor do such arrangements optimally prevent bridging and rat-holing well upward in the bag as emptying progresses. And such arrangements have not fully recognized how to deal with the tendency of material to lodge in the bag lower portions when the bag is nearly, but not entirely, empty.
A difficulty with the aforedescribed bag tensioning or bag lifting mechanism is that the gas springs sometimes tend to bind. And there is no opportunity to control operation by manipulating gas pressure; the gas spring is permanently sealed and, for a particular rod position, such pressure is fixed.
And aside from the matters of assuring smooth powder flow during all phases of bag emptying, prior art arrangements seem not to have appreciated how smooth, substantially bridge-free bag unloading can be improved by process control which changes the operation of a bag unloading machine as a function of the degree to which the bag is emptied.
An improved bag unloading machine and method which address these deficiencies perceived in prior art arrangements would be an important advance in this field of technology.
OBJECTS OF THE INVENTION
It is an object of the invention to overcome some of the problems and shortcomings of prior art arrangements.
Another object of the invention is to provide a new machine and method which help assure smooth powder flow at initial discharge from a full bag.
Another object of the invention is to provide a new machine and method which help assure smooth powder flow when the bag is only partially full.
Yet another object of the invention is to provide a new machine and method which help assure smooth powder flow when the bag is nearly empty.
Another object of the invention is to provide a new machine and method which involve monitoring of one or more process variables.
Still another object of the invention is to provide a new machine and method which change the operation of a bag unloading machine as a function of the degree to which the bag is emptied.
Another object of the invention is to provide a new machine and method which involve monitoring of one or more process variables.
Still another object of the invention is to provide a new machine and method which provide substantially bind-free operation of a bag tensioning mechanism and the opportunity for process-based control of such mechanism.
How these and other objects are accomplished will become apparent from the following descriptions and from the drawings.
SUMMARY OF THE INVENTION
Aspects of the invention involve improvements in a machine for unloading a bulk-material bag of the type having a bottom portion, a side portion and a transition portion between the bottom and side portions. In this specification, such side portion and transition portion are also referred to as the first side portion and the first transition portion, respectively. The machine has at least one apparatus aiding discharge of the material from the bag.
In the improvement, the apparatus includes a tri-section panel mounted for movement on the machine, thereby configuring the panel to contact the bottom, transition and side portions of the bag. The tri-section panel includes first, second and third segments and in a specific embodiment, the first and second segments are angle-mounted to one another and the second and third segments are angle-mounted to one another. More specifically, at least two (and, preferably, all three) of the first, second and third segments are substantially planar.
The tri-section panel has an actuator coupled to it at a pivot-type actuator joint. A pivot mount is also coupled to such panel at a location laterally spaced from the actuator joint. In a specific embodiment, the tri-section panel includes an inward edge and the pivot mount is coupled to the tri-section panel between the inward edge and the actuator joint.
Other features of the invention facilitate changing the operation of the bag unloading machine as a function of the degree to which the bag is emptied and the resulting compressibility of the bag. That is, a controller is coupled to the actuator and regulates its movement. In a specific embodiment where the actuator is a pneumatic cylinder, the controller regulates movement of the cylinder rod. But however such actuator is embodied, the controller regulates actuator movement as a function of bag/material compressibility.
Another aspect of the invention recognizes and deals with the propensity of powdered material to lodge in the bag lower portions when the bag is nearly, but not entirely, empty. In a highly preferred embodiment, the machine includes a bag lifting mechanism positioned above the tri-section panel and connected by hooks or the like to the top bag portion. The bag lifting mechanism includes an extensible device such as an exemplary air bladder. In a specific embodiment, there are thre
Becker Steven L.
Kelly Thomas G.
Nauman Jeffrey M.
Bocanegra Jorge S.
Jansson, Shupe Bridge & Munger, Ltd.
Kashnikow Andres
Schenck AccuRate, Inc.
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