Classifications

• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D7/00—Control of flow
  • G05D7/06—Control of flow characterised by the use of electric means
  • G05D7/0605—Control of flow characterised by the use of electric means specially adapted for solid materials
• • 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 relates to the continuous precision metering of pulverulent product in a process for the continuous preparation of a mixture produced from different constituents at least one of which is formed of said pulverulent product. More specifically, the invention relates to an apparatus and an installation for delivering a constant, continuous, but adjustable flow rate, of powdered product.
• this comprises a feed hopper including a vertical capacity mounted on weighing means and directly feeding a extraction system, in particular an extruder screw located at the bottom of this capacity.
• the interval _d_t between two effective measurements is of the order of 30 s with such a known device.
• the weighing system must be calibrated regularly. This calibration is extremely delicate and immobilizes the device for too long a time which is conventionally one day.
• a cylindrical weighing device comprising a rotor defining cells or pockets which are filled with product and a frame for this rotor mounted on a dynamometric weighing device.
• the product is supplied discontinuously in each of the pockets or cells.
• the regulation is neither precise nor rapid, since the interval cft of sample LLonnage of the measurements is necessarily greater than the time of passage of the volume of a pocket.
• the accuracy of the output flow depends, essentially, on the accuracy in the rate of filling and emptying of the pockets or cells.
• significant wear and tear caused by the friction of abrasive product on the sealing faces, is inevitably created at the joints, between the bottom and the chassis cover and the rotor defining the pockets, causing leaks and disturbances.
• the present invention aims to remedy the aforementioned drawbacks of the devices of the prior art. Its object is therefore to provide an apparatus and an installation making it possible to deliver a constant, continuous, but adjustable flow rate at will, of a pulverulent product, in which the product cannot inadvertently and uncontrolled fuse and which allows the Continuous and precise control and regulation of the actual value of the flow actually delivered at the output.
• the invention also aims to provide such an installation whose longevity and reliability are increased, that is to say in which the phenomena of wear or abrasion are negligible.
• the installation for continuous dosing of pulverulent product according to the invention is characterized in that it comprises at least:
• a storage hopper placed under the valve of a storage hopper to be always filled with product between two upper and lower levels, . provided with an outlet duct opening in the capacity above the upper level and the passage section of which is controlled by a flow regulator,. internally comprising a withdrawal means in the form of a motorized endless conveyor with vanes, immersing in the product and passing through a feed chamber opening above the orifice of the duct and to which the conveyor continuously supplies a flow of product greater than the maximum flow capacity of the duct,
• - And regulation means calculating, with respect to a set value, the real value of the flow delivered, as provided by the appraisal system and acting on at least the flow regulator of the outlet conduit.
• FIG. 1 is a schematic overview of an installation according to the invention
• FIG. 2 is a view in longitudinal section of an apparatus according to the invention
• FIG. 3 is a partial view in cross section along line III-III of FIG. 2,
• - fig. 4 is a partial section along line IV-IV of FIG. 2
• - fig. 5 is a partial view in detail in section, on a larger scale, of the means for extracting a supply device according to the invention
• FIG. 6 is a schematic view of another embodiment of an installation according to the invention.
• FIG. 7 is a top view of a control device according to the invention, the upper part of the chassis, supporting the sole and the adjustment flap of the supply device, not being shown, - FIG. 8 is a view along line VIII-VIII of FIG. 6,
• - fig. 9 is a view along line IX-IX of FIG. 7,
• - fig. 10 is a detail view in section along the line X-X of FIG. 8.
• the invention relates to an installation capable of delivering a constant, continuous, but adjustable flow at will, of a pulverulent product and of carrying out the control and continuous regulation of the real value of this flow actually delivered.
• the installation according to the invention comprises a hopper 1 for storing the pulverulent product.
• the hopper 1 is intended to deliver the pulverulent product, not necessarily continuously, by a hatch or a valve 2, to an apparatus 3 capable of delivering a constant, continuous flow, but adjustable at will, controlled by means of '' a regulation circuit 4.
• the apparatus 3, shown in figs. 2 to 5, includes a buffer capacity 3a which is not necessarily continuously supplied with product and means 6, 7 for extracting the product.
• These means 6, 7 deliver a flow D. of product into a supply chamber 112 and into an upper orifice 8 of an outlet duct 9 of the apparatus 3.
• the value of this flow D. is greater than that of the maximum admissible flow rate D volunteerin this duct 9, so that this duct 9 is stuffed with product which is constantly regenerated.
• the part excess of the flow D .., delivered to the upper orifice 8 is recycled by gravity into the buffer capacity 3a, as soon as the product leaves the supply chamber 112. It is thus ensured that the outlet conduit 9 delivers, in permanently, a continuous flow D p from the orifice 8.
• the means 6 r 7 consist of drive plates 7 mounted regularly spaced along at least one cable or traction chain 6_ driven, preferably at constant speed. These means b, 7 are arranged to flow from the bottom bottom 85 of the capacity 3a, passing through the supply chamber 112, then around a first upper guide roller 86 located substantially above the orifice 8 upper of conduit 9, to a second upper guide roller 87 located on the opposite side of the outlet orifice 8 and above the maximum upper level N_ of the product in capacity 3a, then to a lower guide roller 88 located near from the bottom 85 of the capacity 3a, substantially below the minimum lower level N_ of product in this capacity 5.
• the extraction means 6, 7 carry out mixing of the product and recycling of the excess flow rate of product not poured in the outlet orifice 8.
• the device 3 comprises an inclined partition plate 89 delimiting the supply chamber 112 and disposed above the trajectory of the means 6, 7 of extr action between the lower guide roller 88 and the upper outlet orifice 8.
• the product drive plates 7a_ extend transversely to their direction of travel along the arrow f and over the entire width of the supply chamber 112 and are mounted on the cables 6a by a wing 102 fixed to a crimping block 101 connecting two cable segments 113.
• the lower guide roller 88 and the upper guide roller 86 which is situated substantially above the orifice 8, are arranged in such a way that the drive plates 7a_ are flush at least up to '' at orifice 8, on the one hand, the separating sheet 89 whose shape is adapted to allow the passage of cables 6 and crimping blocks 101 (fig. 4) and, on the other hand, an outer wall 104 forming part of a closed casing 90, defining the capacity 3a_.
• the inclined wall 104 is parallel to the sheet 89 with which it defines the chamber 112.
• the upper end 114 of the partition sheet 89 is located at least substantially in the horizontal plane passing through the highest point 115 of the orifice 8 upper of the outlet conduit 9, while the lower end is located substantially in the plane of level j .
• the partition plate 89 and the various guide rollers 86, 87, 88 are mounted integral with the casing 90.
• the outlet duct 9 is also rigidly associated with this casing 90 and the outlet orifice 8, opening into the capacity 3, is formed by an opening in the outer wall 104 of this casing 90.
• the device 3 comprises a motor 91 cooperating with a reduction gear 92 which rotates one of the guide rollers 86.
• the motor 91 and its reduction gear 92 are mounted on the upper wall 93 of the casing 90.
• the output shaft 94 of the reduction gear 92 rotates a toothed pinion 95 which drives a transmission chain 96 cooperating, moreover, with a toothed pinion 97 integral in rotation with the rotation shaft 98 of the guide roller 86.
• the casing 90 has a supply opening 100 offset transversely relative to the means 6, 7 and to the supply chamber 112 (FIG. 3), so that the product discharged from the hopper 1 does not directly interfere with the extraction means 6, 7.
• the casing 90 is supported by weighing means 15, for instantaneous measurement of the weight of the apparatus 3.
• These means 15 are constituted by sensors and are connected to the circuit 4 which comprises a calculation and management device 16, of the type microcomputer, composed of a keyboard 26 and a screen 27.
• the device 16 is connected to the sensors 15 by an amplifier 28 and a converter 29.
• the device 16 is, moreover, connected to means of comparison and correction 17 themselves connected by a line 109 to a means 10 for controlling the passage section of the conduit 9.
• the means 10 is preferably designed in the manner of a flow controller comprising, for example, a shutter of the guillotine type, of ascending or descending orientation, controlled by a motor 18. The installation operates as follows.
• the device 16 controls The supply to the motor 91 of the device 3 which has been filled to level N_ by the hopper 1.
• the device calculates the flow rate D supplied by the pipe 9 using the weighing sensors 15, at the density of the product and the characteristics of the conduit 9.
• the device 16 provides the comparator 17 with a signal 108 corresponding to this actual measured flow rate value D ⁇ and a signal 107 corresponding to the preset preset value displayed by the device 16.
• the comparator 17 establishes , by comparison, a control signal to drive the motor 18 and partially open or close, in an adjusted manner, the passage section of the conduit 9 through the shutter 10 for controlling and regulating the flow rate.
• the power supply to the motor 91 is placed under the dependence of the device 16 to rotate at constant speed.
• a variant of flow regulation could involve a variable speed motor 91 which would then be controlled by the comparator 17. In some cases, regulation by flow and speed controls may be provided.
• Weight measurement by weighting is used to control the valve 2 and ensure the filling of the device 3. It can also, in a primary or secondary manner, be provided to control the filling of the device 3 by detectors 30 and 31 of levels N_ and N ⁇ controlling, by the device 16, the operation of the valve 2.
• FIGS. 6 to 10 show, schematically, another version of the installation comprising all of the means described above which are assigned, in the drawings, the same references.
• the conduit 9 is responsible for supplying a regulating device 5 intended to supply a flow rate D i.
• the apparatus 5 comprises a measurement path, of constant length and shape, on which the product delivered by the conduit 9 is moved.
• This path is associated with means 15 for instantaneous measurement of the actual weight of product present on the path, with the regulating circuit 4, and with means 13 for instantaneous measurement of the effective speed at which the product moves along this path, from such means 13 also being associated or connected to circuit 4 by a line 24.
• the regulating apparatus 5 comprises a horizontal circular hearth 11 carried by a vertical axis 21 mounted on a chassis 22 adapted on the weighing means 15.
• the apparatus 5 also comprises means 19, 20 for driving in rotation of The sole and a device 23 for mechanical extraction.
• the sole 11 is formed by a gutter 12 in the form of a circular crown, open on the top, of concave radial section, defined by a surface 52 in a segment of a circle.
• the gutter 12, which defines the measurement path of constant length and shape, is constituted by a part whose actual weight, set with precision, represents a reference tare. This part is formed by the gutter 12, but also by the means of connection with the axis 21, that is to say a circular crown 50 and spokes 53.
• the sole 11 is mounted, by the axis 21, in a bearing 43 carried by crosspieces 44 forming part of a lower frame 40 constituting the chassis 22 with an upper frame 41 to which it is linked by uprights 42.
• the axis 21 is connected to the means 19, 20 comprising a geared motor group 46 fixed, by a flange 48, to a crosspiece 47 of the lower frame 40.
• the output shaft 64 of the group 46 is provided with a pinion 65 linked by a transmission chain or the like 67 to a pinion 66 adapted on the shaft 21.
• the chassis 22, carrying in particular the bottom 11 and the means 19, 20 is mounted, by the means 14, 15, on a frame 35 resting on the ground by elastic supports 39.
• These means 14, 15 comprise , first of all, an axis of oscillation AA 'extending perpendicular to a line 36 passing through the axis 21 and the output shaft 64.
• the axis of oscillation is, moreover, provided for correspond, substantially, to the static balancing axis of the mobile assembly constituted by the chassis 22 and the means that it carries.
• the axis AA ′ is, for example, defined by knives 62 (FIG. 9) carried by longitudinal members 60, 61 integral with the upper frame 41 of the chassis 22. The knives 62 are placed in knife support grooves 63 provided to the upper part of brackets 59 rising from the frame 35.
• the chassis 22 is carried by the frame 35 with the interposition of a dynamometric sensor 14, of the static type, for example with a
• the sensor 14 is arranged on the line 36 while being mounted between a plate 38 secured to the frame and a crosspiece 45 of the lower frame 40.
• the static vacuum balancing of the assembly, chassis 22 - elements that it carries, makes it possible to impose only low stresses on the sensor 14 which thus has a high sensitivity.
• the means 13, associated with the gutter 12 for measuring the speed of rotation, consist of an inductive proximity detector connected to the line 24 and carried by the chassis 22 to be placed opposite the rays 53 whose passage it detects .
• the gutter 12 is arranged, by the means which carries it, so that the open annular surface which it defines is locally placed under the outlet orifice of the conduit 9 which is extended by a feed chute 32 whose axis vertical 33 passes through the axis AA 'and the median circle _ £ of the gutter 12, being located on one side of the line 36 (fig. 7).
• the chute 32 is mounted on the upper frame 41 by elastic blocks 75 allowing relative movement.
• the chute 32 has a wall 76, upstream relative to the direction of rotation of the gutter 12 according to arrow arrow f. and which is extended downward to be flush, by a conjugate edge 77, the surface 52 of the gutter 12.
• the chute 32 has a downstream wall 78 providing, by its lower edge 80 distant from the surface 52, an opening 79 for the passage of the powdery product (fig. 10). This opening 79 corresponds to a flow passage maximum D ,, delivered by the device 3.
• the lower edge defines a re-entrant angle.
• the wall 78 is, in this example, associated with the flow control means 10.
• a means is here constituted by a sliding mounted hatch, in particular by rails 81.
• the hatch 10 has a head 84 linked, by an axis 83, to the motor 18 carried by the chute 32 and capable of moving the hatch over a height H to adjust the flow D-, delivered on the gutter 12.
• the lateral walls of the chute 32 are extended by flaps 111 made of flexible material flush with the surface 52.
• the extraction device 23 consists of a rotor 54, of horizontal axis 56, placed parallel to the plane of the gutter.
• the rotor is arranged so that an axis 37, vertical and perpendicular to the midpoint of axis 56, passes through the axis of oscillation A-A ', being located on the middle circle _ £ and in such a way that this point is preferably placed at an equal distance, but opposite line 36 with respect to axis 33.
• Axis 56 carries blades 55, radial or helical, provided at the end of brushes or flaps 58 able to rub the angular portion which they cover of the surface 52 of the gutter 12.
• the axis 56 is mounted in bearings 57 of the frame 41 and cooperates with drive means 34 comprising an angular gear 68 provided at the upper outlet of the shaft 64 and a chain or the like 71 surrounding two sprockets 70, 72 belonging, respectively, to the reference 68 and to the axis 56.
• the speed of rotation of the rotor 54 is thus synchronized with that of the gutter 12.
• the number, the characteristics of the blades 55 and their axial length, as well as that of the rotor 54 are, in particular, a function of the diameter and of the speed of rotation of the sole 11.
• good results have been obtained with a rotor 54 whose length was between 150 mm and 200 mm, in particular of the order of 180 mm, for a sole 11 whose overall diameter was of the order of 985 mm.
• the middle circle _C having a diameter of the order of 800 mm, the circle forming the radial section of the bottom 52 of the gutter 12 having a radius of the order of 250 mm.
• the speed of La Sole 11 was 24 rpm.
• the rotor 54 rotated twice as fast as the sole 11.
• the device 23 evacuates the pulverulent product from the gutter 12 in a receiving chute 73 secured to the chassis 22 and which includes a screen 74 extending this chute 73 on the outside and above the rotor 54 of the device 23 to recover any projections of powdery product.
• the pulverulent product is supplied according to the flow rate D,
• the computing center 16 determines the actual value of the flow rate D, effectively measured by means of the signals coming from the weighing sensor 14 and from the sensor 13 for measuring the effective speed of the hearth 11. At each pulse supplied by the detector 13, the computing center 16 supplies comparator 17 with a signal 108 corresponding to this actual measured value of the flow rate D i. The computing center 16 also supplies the comparator 17 with a signal 107 corresponding to the setpoint value of the flow D-. desired output. The comparator 17 then establishes, from the comparison of the signals 107, 108, a control signal 109 for the servomotor 18 of the flow control flap 10 D- ,, so that The height of product deposited in the gutter 12 corresponds to a flow rate D, actually delivered equal to the set value. The means 23 ensure complete extraction of the product from the gutter 12, regardless of the height of the product deposited on the floor 11. In normal permanent operation, the value of D is equal to that of D ,.
• the installation thus makes it possible to continuously deliver a flow D, at constant output and adjustable at will and ensures automatic regulation continuously of this flow D, relative to the set value.
• the invention is, more particularly, applicable to a pulverulent product of homogeneous and constant particle size less than 1 mm, in particular in the manufacture of anode paste.
• the invention is, however, applicable in many industries (food industry, public works, chemistry, pharmacy, ... ) .

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Automation & Control Theory (AREA)
• Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
• Weight Measurement For Supplying Or Discharging Of Specified Amounts Of Material (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9377760

Family Applications (1)

Country Status (3)

Family Cites Families (7)

• 1989
  • 1989-01-09 FR FR8900460A patent/FR2641625A1/fr active Pending
• 1990
  • 1990-01-09 EP EP19900901834 patent/EP0454714A1/fr not_active Ceased
  • 1990-01-09 WO PCT/FR1990/000018 patent/WO1990007740A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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