RU2042930C1 - Method of portion weighing of dosage of liquid - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: method of portion weighing of dosage of liquid is performed by setting of vessel 1 into loading position, by opening of valve 12 for filling of vessel with portion of specified weight, by stopping of filling by shutting valve followed by emptying of vessel. In this case vessel hinged on axle 2 with gravity center displaced towards tipping over is returned into loading position each time with counterweight 5. Strength of current in immobile coil 8 with open ferromagnetic core 9 before filling is set by regulating element 11 in accordance with graduation characteristic. Magnetic circuit of coil core in this position is closed with ferromagnetic armature 6 made fast to outer surface of vessel. Filling is performed till moment of electromagnetic attraction of coil with closed magnetic circuit equals moment of tipping over gravity force of filled vessel. Vessel is emptied in process of tipping over. Counterweight is also imparted with damping capabilities when vessel moves. EFFECT: increased functional efficiency thanks to use of electromagnetic counterbalancing force, increased precision of operation due to partial suppression of internal force with movement of vessel. 2 cl, 1 dwg, 1 tbl

Description

 The invention relates to methods for portioned weight dosing of liquids, allowing to provide various technological processes in the food, chemical and other industries with portions of liquids of the same weight and frequent reconfiguration according to technological requirements for portions of other scales.

 Known automatic portioned scales and dispensers designed to weigh liquids in equal portions for packing or batching (Viktorov V.A. Lunkin B.V. Measurement of the quantity and density of various media. M. Energia, 1973, pp. 23-24; P. Profos, Measurements in Industry, M. Metallurgy, 1980, pp. 311-328).

 These devices are, as a rule, an equal-arms rocker, to which a bucket is suspended on one side and a weight on the other. Above the bucket is a hopper, the inlet of which is closed by a damper controlled by the balance. Rising up after unloading, the bucket opens the damper and fluid begins to flow into it by gravity or with the help of feeders. When the bucket is full, the flap closes.

 Known weighing devices, which use a load of known mass as a balancing force, have a relatively complex structure, the elements of which require precise manufacture and contain spring elements having insufficient stability. The balancing process does not allow a smooth change in the portion weight, since the portion weight can only be changed discretely, by removing or adding weights.

 The technical solution, selected as a prototype, is a method of portioned weight dosing of liquid, in which, in order to increase accuracy and reliability, the vessel is set to its initial position, filled through an open valve, and then the dosing process is interrupted using push-button switching elements, the total pressing force of which corresponds to the weight of a portion of liquid (ed. St. USSR N 1666926A, CL G 01 F 13/00, 1991).

 However, this method, although it improves the accuracy and reliability of dispensing viscous liquids, does not provide a smooth reconfiguration of the system for dispensing portions of other weights, since the switching elements have a rigid relay static characteristic, and discrete tuning is achieved by changing the number of switching elements used. With the required large portion weight, it is necessary to use many switching elements, which complicates the design and reduces reliability. In addition, in practice, the disadvantages inherent in the spring elements.

 The aim of the proposed method is to increase the efficiency of operation due to the use of electromagnetic balancing force, as well as to increase the clarity of work due to the partial repayment of the inertia force when the tank moves.

 This goal is achieved by the fact that in the known method of portioned weight dosing of liquid, which consists in installing the container in the loading position, opening the valve for supplying liquid, dosing to a predetermined portion weight and stopping dosing by closing the valve and then emptying the container, a certain in accordance with the calibration characteristic, the current strength in the coil with an open ferromagnetic core, which is rigidly fixed to a fixed the first rack, and the magnetic circuit of the core in the loading position of the tank is closed with a ferromagnetic anchor, moreover, the anchor is rigidly fixed to a container pivotally suspended in the rack and balanced by a counterweight with a displaced center of gravity relative to the suspension axis and the filling is carried out until the moment from the electromagnetic force of attraction of the coil to the moment from the overturning capacity is equal the gravity of the liquid and the container are emptied in the process of overturning. In addition, when the container is rotated, additional air damping creates a concave counterweight surface.

 A comparative analysis of the claimed technical solution with the prototype shows that the claimed method differs from the known one in that the balancing force is created due to the electromagnetic force of the coil with a closed magnetic circuit, and the reconfiguration of the system is carried out by a regulatory element in the electrical circuit of this coil with a ferromagnetic core in accordance with previously removed calibration characteristic. In this case, the counterweight is endowed with damping ability when turning the tank. These differences allow us to conclude that the claimed technical solution meets the criterion of "novelty."

 Signs that distinguish the claimed technical solution from the prototype, are not identified in other technical solutions when studying this and related areas of technology devoted to weighing, measuring mass flow rate and liquid level and, therefore, provide the claimed method with the criterion of "inventive step".

 Portion weight dosing is widely used in many industries, for example, food, it is used in the preparation of grinding batches in mills, mixtures for the production of chocolate masses in the confectionery industry, with the addition of flour, soda, salt, sugar and other additives in the production of bread, during packaging flour, cereals, sugar and other products, and therefore, the claimed technical solution is industrially applicable.

 Carry out the claimed method using a device whose functional diagram is presented in the drawing.

 The device comprises a container 1 pivotally suspended on the axis 2. The axis is fixed in racks 3. rigidly mounted on the base 4. The container is balanced in the loading position on the axis of the counterweight 5. A ferromagnetic armature 6 is attached to the container wall from the outside, in the form of a metal plate of corresponding thickness, closed thin non-ferromagnetic gasket 7. The latter provides greater clarity and stability of the moment of gaining critical portion weight. A coil 8 with a ferromagnetic core 7 is fixed on one of the racks so that in the loading position of the container the magnetic circuit of the coil would be closed by means of an armature. The electrical circuit of the coil includes a regulating 11 and measuring 10 elements, as well as a source of electrical energy 14.

 The fluid flow (shown by double arrows) through the valve 12 enters the tank 1 and is shut off by the valve at the signal of the liquid portion set collection sensor 13 electrically connected to it, which is also rigidly fixed to the rack.

 When the device is operating, the container 1 is first under the influence of the counterweight 5 in the loading position. When you turn on the device, the magnetic circuit of the coil 8 in the form of a core 9 by means of an anchor 6 fixed with a gasket 7 is closed and the coil develops a certain, depending on the position of the regulating element 11, holding the electromagnetic force proportional to the current flowing in the electric circuit: source 14 electric energy, coil 8, regulating 11 and measuring 10 elements. In the same position, the portion set sensor 13, made, for example, on the basis of a reed switch, opens the valve 12 with its signal. Through the last tank, it is filled with liquid. The control element 11 sets the pre-required amount of current in the circuit, corresponding to the weight of the dosed liquid, and controls its value in accordance with the calibration characteristic for the measuring element 10. As the fluid is collected, the gravity increases and the corresponding tilting moment. As soon as this moment becomes equal to the holding electromagnetic moment, the container 1 will begin to rotate on the axis 2, mounted in the racks 3 on the base 4. At this moment, the sensor 13 is activated and closes the valve 12 with its signal, thereby interrupting the flow of liquid into the tank 1. In the process the tipping of the container relative to the axis, it is emptied, and the emptying of the tank ends when it turns to the extreme unloading position indicated by the corresponding stops (not shown). After unloading under the influence of the counterweight 5, the tank returns to its initial loading position, in which again, if the state of the regulating element 11 has not been changed, the holding electromagnetic force of the coil is restored, and the process then proceeds as described above. The capacity approach to the extreme positions is mitigated by the damping force of the counterweight due to air resistance, which significantly increases the clarity of the device.

We obtain the equation of the static characteristic of the device, for which we use the condition that the algebraic sum of the moments of forces acting on the container in the loading position should be equal to zero:
M ₁ + M ₂ M ₃ M ₄ 0, (1) where M ₁ m ₁ xgxl ₁ moment of gravity from the dosed liquid,
m _{1 is the} mass of the dosed liquid;
g acceleration of gravity;
l _{1 the} distance from the center of mass of the liquid to the axis of rotation of the tank.

M ₂ m ₂ xgxl ₁ moment of gravity of the container;
m ₂ own weight of the tank;
M ₃ F xl ₂ moment of the electromagnetic force of the coil;
F k ₁ x I electromagnetic force of the coil, proportional to the coefficient of proportionality k ₁ , depending on the number of turns of the coil, the material and the geometric dimensions of the core of the electromagnet, the current I flowing through the coil;
l ₂ shoulder forces F relative to the axis of rotation of the tank;
M ₄ m ₃ xgxl ₃ moment of gravity of the counterweight;
m ₃ counterweight mass;
l ₃ shoulder from the center of gravity of the counterweight to the axis of rotation of the tank. The condition M ₁ M ₃ + M ₄ M _{2 will} be called critical, since when it is reached, the overturning of the container with liquid begins. Since the moment M ₂ , M ₃ , M ₄ for a given installation is constant, it is necessary to change the value of M ₁ to change the weight of portions of the liquid. We obtain the dependence of the mass of the dosed liquid on the state of the regulating element if we substitute the equation in (1) for the above relations for each moment. Then we get:
m ₁ k ₁ x I xl ₂ / gxl ₁ + m ₃ xl ₃ / l ₁ m ₂ . (2)
For a particular installation, g, l ₁ , l ₂ . m ₂ , m _{3 the} values are constant, l _{3 the} tuning value. Taking into account IU / R, at a constant electric voltage U, the mass of the dosed liquid m ₁ depends on the resistance value R, which is uniquely determined by the state of the regulating element.

Then the equation of the static characteristic is written:
m ₁ k ₂ / R + m ₃ xl ₃ / l ₁ m ₂ (3) Here the coefficient k ₂ k ₁ xl ₂ x U / gxl ₁ (3) can also be represented as
m ₁ kx I + b, where kk ₁ xl ₂ / gxl ₁ ; bm ₃ xl ₃ / l ₁ m ₂ constant coefficients.

 Therefore, the obtained equation of the static characteristic of the system under consideration is the equation of a line with an angular coefficient -k.

 Calculations and experimentally established that the weight of the dosed liquid in a certain range linearly depends on the current flowing through the coil. Thus, a smooth change in the strength of the current flowing through the coil, in accordance with the previously taken calibration characteristic, leads to a proportional change in the electromagnetic force of the coil with a closed magnetic circuit and, accordingly, in the portion weight of the dosed liquid. The use of electromagnetic force greatly simplifies the system and the process of its reconfiguration, and consequently, significantly increases the efficiency of functioning.

 The following is a specific example of the implementation of the proposed method.

The method was carried out on the installation, the functional diagram of which is presented in figure 1. The tank is made in the form of a rectangular parallelepiped with an inclined (40 ^° ) front wall to the base, with a volume of 0.0016 m ³ and hinged to the axis by the rear wall in its middle. An anchor with a non-ferromagnetic gasket is fixed in the upper part of that wall, and the counterweight pin in the lower part. The coil is wound with a PEV-2 wire with a diameter of 0.10 mm, contains 11 thousand turns, its resistance is 2.4 kOhm. The U-shaped metal core of the coil was taken with a cross section of 8x15 mm ² . The counterweight is made in the form of a threaded pin on which an open rectangular box of the corresponding mass was fixed. Water was used as a liquid. The current flowing through the coil was changed by a potentiometer with a resistance of 5 kOhm. The current was measured with a 50 mA dc milliammeter. A dosed portion of water at each current value was weighed in triplicate on a laboratory balance. Previously, before the experiments, a calibration characteristic was taken proportional to the dependence of the critical mass, at which the capacitance is no longer held by the electromagnetic force of the coil, on current. The latter varied in the range of 25-50 mA. The results of these measurements are tabulated.

 The table shows that the relative dosing error of the experimental setup does not exceed 4.13%. Using the claimed invention can significantly simplify the design and process of reconfiguring the system, reduce downtime and increase productivity with a small dosing error, and thereby significantly increase the technical efficiency of production.

Claims (2)

 1. METHOD FOR PORTIONAL WEIGHT DOSING OF LIQUID, including setting the container in the loading position, opening the valve, filling the container to a predetermined portion weight and stopping filling with closing the valve, characterized in that the container with a displaced center of gravity is suspended on an axis, each once return the container to the loading position by means of a counterweight, set the regulating element before filling determined in accordance with the previously taken calibration characteristic By static current in a coil with an open ferromagnetic core, which is rigidly fixed on a stationary rack, and the magnetic circuit of the core in the loading position of the container is closed by a ferromagnetic anchor, which is rigidly fixed on the outer surface of the container, and when the moment exceeds the gravity force of the filled container, the moment from the holding container the electromagnetic force of the coil with a closed magnetic circuit, the valve is closed and the tank is empty during the tipping process.  2. The method according to claim 1, characterized in that they create an air damping by the surface of the counterweight when capsizing and returning the tank.

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