Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G11/00—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers
  • G01G11/08—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having means for controlling the rate of feed or discharge
  • G01G11/083—Apparatus for weighing a continuous stream of material during flow; Conveyor belt weighers having means for controlling the rate of feed or discharge of the weight-belt or weigh-auger type

Definitions

• the invention concern apparatus and method for weighing continuous stream of pourable (bulk) material, comprising a first housing for receiving the material to be weighed, a second housing for weighing the material and a frame, said housings having means for moving the material in portions from said first housing to said second housing and releasing the material therefrom back in a new continuous stream of material.
• Various types of apparatus are known for weighing of loose or pourable material. It is common to use flow weighing, or dynamic weighing scales, which refer to apparatus with one or more weighing sensors installed beneath a conveyor belt. The part of the conveyor belt which is above the weighing sensor at any time assumes the role of the weighing platform. Thus the material is continuously weighed without interrupting its flow. Such apparatus functions well when the material to be weighed does not tend to clot or stick.
• portion scales are known. Most portion scales are based on interrupting the flow of the material and channelling it into two or more separate flows or portions. Each portion is then weighed separately. From German Patent DE-C 3235039 a typical weighing and dosing apparatus is known. The patent describes apparatus where pulverised material is feed into a housing with dosing means where each dosing is weighed and then released again into a new material stream.
• a disadvantage of these types of weighing devices are fex. that flow scales are hypersensitive for weighing of fine-grained material. The material tends to pile up and clot onto the moving parts of the equipment, particularly when it is wet. This requires greater maintenance and cleaning, and the accuracy of the equipment is correspondingly reduced.
• Another disadvantage of dynamic weighing devices is that they cannot be zero-calibrated while the weighing is actually being performed.
• a disadvantage of portion scales is the large number of moving parts that the equipment contains, resulting in high levels of maintenance. For example, the opening of the weighing tray is often performed by using compressed air, which may have an impact on the weighing accuracy. Furthermore, the material flow is often broken up into portions, being too large for accurate weighing.
• the object of the invention is to present apparatus and method which is simple and requires little maintenance and supervision, but at the same time contributes to high accuracy in weighing of loose pourable material.
• the flow of material is broken up into many smaller and more accurate controlled portions for weighing, so that the method approaches that of dynamic weighing.
• the invention is characterised in that the first housing having an outer wall unit and a bottom plate, the bottom plate having an aperture for feeding of the material through, the second housing having an outer wall unit and a bottom unit, the bottom unit including a weighing device for receiving of the material to be weighed in portions, the means for moving the material including preferably one or more pair of shovel devices, fastened to one or more axles extending vertically through the housings, the shovel device moving the material in portions from the first housing to the second housing and therefrom, into a continuous stream of material in such a way that accurate weighing of each portion can be conducted in the second housing on the weighing device without disturbance from a prior or a latter portions of material.
• first and second housing are cylindrical and co-axial, the axle extend through the first and second housing and the shovel devices being connected thereto and their rotation co-ordinated.
• the means for moving the material comprises one or more pairs of axle's extending vertically through the first and second housing, one or more pair of shovel devices, fastened to the axles, driving means connected to the axle for rotating it and the shovel devices.
• the shovel device extending from the axle towards the outer wall unit of the first and the second housing.
• the aperture in the bottom plate of the first housing spanning over a 15°- 180° of the bottom plate's circular surface, more specifically 45°-90° and in particular a 50°-75°.
• the weighing device comprises a strain gauge and the weighing device being connected to /or including a computer system for receiving weighing signals from the weighing device and utilising the weighing signals representing individual portion weighings to compute weighing measurements representing the weight of the actual material stream.
• the method is furthermore characterised in that the material is fed with one or more shovel devices through an aperture in the bottom plate of the first housing onto a weighing device in the second housing where the material is weighed in portions and then removed from the weighing device by a second shovel device and directed to a new stream of material all done in such a way that it is possible to conduct weighing of one portion of material at a time without disturbance from a prior or latter portion of the material.
• Fig. 1 shows a perspective view of the apparatus.
• Fig. 2 shows in perspective view with cut through the outer wall unit of the first housing of the apparatus.
• Fig. 3 shows a vertical cross-sectional cut A-A of the apparatus.
• Fig. 4 shows the apparatus seen from above.
• FIG. 1 shows one example of the basic design of the invention.
• a drum alike device comprising a first housing (2) with outer wall (12) and a collecting surface or bottom plate (9), forming a housing for receiving the material to be weighed.
• the first housing (2) is cylindrical and the collecting surface or bottom plate (9) is smooth, but equipped with an aperture or hole ( 10) through which the material to be weighed falls onto a weighing platform (4) underneath.
• a rotary axle ( 1 1) extend to which shovel blades (5, 6) are attached in order to control and activate the feeding-through of the material, both from the first housing (2) and from the weighing platform (4) of the second housing ( 15).
• the axle ( 11) with attached blades (5, 6) driven by a motor
• the upper blade (5) forms a dividing wall within the first housing, extending from the rotary axle (11) to the outer wall unit ( 12), so that when rotated, the material in the housing (2) is moved along with the blade in direction of rotation of the axle. It is quite conceivable to use more than one pair of blades and thereby dividing the first housing into two or more compartments. The same applies to the blades used to transfer the material from the weighing platform of the second housing.
• Fig. 2 shows a arrangement and the positioning of the shovel blades (5, 6) for controlled feeding-through of the material with respect to the bottom plate (9) and weighing platform (4).
• Fig. 3 shows a vertical cross-section cut A-A of the apparatus.
• the material drops onto the bottom plate (9) of the first housing (2).
• the upper blade (5) which is fixed to the rotary axle ( 11)
• the material is transferred in controlled amounts to an aperture ( 10) in the bottom plate, where it drops through onto the weighing platform (4) of the second housing.
• Each amount is weighed before being transferred by the lower shovel blade (6) from the weighing platform (4) and back into a new or the same material flow.
• a conventional motor/ gear (13) drives the axle.
• the aperture (10) may be designed so as to channel the material onto the weighing platform in a specific way, by fitting the aperture with a funnel or other device.
• Fig. 4 shows an view of the apparatus seen from above. It shows the position of the weighing platform (4) with respect to the aperture ( 10) in the bottom plate (9) of the first housing, and likewise the positioning of the shovel blades (5, 6). Since the weighing platform is located below the bottom plate, it is indicated with a broken line.
• a conventional conveyor belt or worm- shaft may be used to transport the material to the apparatus.
• the material falls onto the bottom plate (9) of the first housing where it accumulates.
• the rotary axle ( 11) revolves continuously and the upper blade (5) transfers or sweeps the material from the feed-in point to the aperture ( 10) in the collecting surface. Since the blade (5) forms a compartment between the rotary axle ( 11) and the outer wall (12) of the housing, it is possible to move all the material that has accumulated on the bottom plate.
• the material flows continuously into the feed-in point. After the blade has passed the feed-in point and swept along the material that has accumulated there since its last revolution, a new controlled amount accumulates, and so on and so forth.
• the material which is transferred and fed through in controlled amounts by this means then drops down through an aperture in the plate.
• the aperture is, in principle, a sector cut out of the circular process of the collecting surface, and may measure anywhere from 10° to 180°. An optimum size of aperture is 50°-75°.
• Other configurations of aperture are conceivable, for example a funnel shape to channel the material in a more specific way onto the weighing platform located beneath it.
• the material is fed onto the weighing platform in controlled amounts. Inserting this equipment into the material flow enables controlled individual amounts to be weighed simply by conventional means.
• the lower blade (6) then transfers the material from the weighing platform (4) in virtually the same way as from the collecting surface, and back into the material flow, for example onto a conventional conveyor belt.
• the invention is not confined to the configuration described here. It may be adapted in various ways without deviating from the basic concept of the invention.
• the first and second housing could be separated and connected only with some kind of channel between the aperture ( 10) and the weighing device (4) to allow the material to be fed there between in portions.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Weight Measurement For Supplying Or Discharging Of Specified Amounts Of Material (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=36699733

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (3)

• 1997
  • 1997-05-22 IS IS4487A patent/IS4487A/is unknown
• 1998
  • 1998-05-22 WO PCT/IS1998/000005 patent/WO1998053283A1/en active Application Filing
  • 1998-05-22 AU AU73503/98A patent/AU7350398A/en not_active Abandoned
• 1999
  • 1999-11-22 IS IS5262A patent/IS1997B/is unknown

Patent Citations (3)

Non-Patent Citations (1)

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