SU1516792A1 - Method of weighing loose materials and weigher for loose materials - Google Patents

Abstract

The invention relates to a dosing technology and can be used in technical means for dosing bulk materials. The method improves dosing accuracy when unloading bulk materials from a feed bin installed with a feeder on a weighing system using an operation evaluating the equality of actual and specified performance, after which the stabilization performance mode is maintained by equalizing the total signal proportional to the decreasing mass of the bunker and the integral of specified performance with the magnitude of the reference signal. When the product is discharged from the feed bin 11 by the feeder 12, the total signal at the output of the adder 17, proportional to the decreasing mass of the bunker and the performance integral, changes with a speed proportional to the difference between the actual and specified performance. An additional adder 4, in one of the inputs of which a delay block 3 is connected, generates a signal proportional to the rate of change of the signal at the output of the adder 17. When aligning the set and actual performance, the signal at the output of the additional adder 4 disappears, and the discriminator 5 generates a command signal to reset the integrator 16, adder 17, storing in the memory cell 7 the signal of the load transmitter 10 and the beginning of a new measurement cycle and stabilization of the performance relative to the reference signal la in the memory cell 3 7. yl.

Description

The invention relates to a weight dosing technique and can be used in technical means for dosing bulk materials.

The purpose of the invention is to improve dosing accuracy.

Figures 1 and 2 are graphs of changes in the mass of the product in the tank, illustrating the method of weight dosing; on fig.Z - diagram of the dispenser.

The essence of the method is as follows.

Figure 1 shows a graph of the process of changing the mass of the product in the tank (curve A) and the cyMMaJjHoro signal (curve B) formed by adding the integral value from the specified capacity and mass of the product in the tank.

At the beginning of the cycle, the performance of the dispenser does not correspond to the specified flow rate (usually lower), which results in accumulation of the integral error in the mass of the unloaded product as the product leaves the bunker. The metering control system changes the feeder capacity in the direction of reducing this error in such a way that The determined time interval is the sum of the integral value of the given flow rate Gp and the current value of the mass are compared (point a,). However, at the moment of mass equalization (point U,), the performance of the feeder will be higher than the specified one, which leads to accumulation of the integral error 4 G (of another sign). Thus, the mass leveling process

Gq, + Gp

generates a process of destabilization of the production capacity of the feeder and leads to an increase in the metering error.

In other words, in order to equalize the sum and Gp with the value of Od, it is necessary to increase the performance of the feeder, and the higher, the greater the deviation of the specified and actual performance.

Fig. 2 is a graph showing the mass change of the product in the tank with the correction of the level of the GO reference signal. At the beginning of the process (in the area d-e) changes in the performance of the feed

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When aligning the total signal Cp + G relative to G, the increments of the variances of the LC are simultaneously measured at set time intervals (polling time).

As soon as the increment value aG decreases to the set threshold (0.1%), which corresponds to the equality of the actual performance to the predetermined value, the signal space proportional to the mass of the product in the tank is stored in the memory cell and then the process of stabilizing the feeder performance is carried out by comparing the total GP + G signal with G ,.

Thus, the process of controlling and stabilizing the performance of the feeder is carried out not only by comparing the sum of the unloaded and remaining in the product tank with the initial (controlled) load mass, but also by choosing a new reference signal proportional to the product mass in the tank at the moment of equalizing given value. Further, the process of controlling the capacity of the feeder with small deviations l G is carried out in a known manner.

The introduction of the reference signal selection operation allows reducing the time to reach the required performance mode, ensuring a stable dosing process and thereby increasing its accuracy.

The bulk materials dispenser (FIG. 3) has a clock generator 1, valves 2, block 3 signal delays, additional, adder 4, discriminator 5 with setting device 6 level, memory cell 7, the output of which through switch 8 is connected to the first input of controller 9 , the information input of the cell 7 is connected to the Shifter -10, on which the feed hopper 11 is installed, a feeder 12 equipped with a drive 13, which is controlled from the adder 14, the first input of which is connected to the output of the regulator 9, and the second to the setting device 15 produce which signal is simultaneously fed through the integrator 16 to the first input of the adder 17, the second input of which is connected

to the power transducer 10, and the output to the second input of the regulator 9. The output of the silometer measuring converter 10 is connected to the input of the comparison device 18, the control inputs of which are controlled by the mass of the product in the tank, and the output connected to the control inputs of the switch 8 and clock generator 1,

The dispenser works as follows.

Bulk material from the hopper 11 enters the feeder 12. The product mass, located in the hopper 11 and the feeder 12, is measured by a force-measuring transducer 10, the output signal of which is fed to the inputs of the comparison device 18, the memory cell 7 and the first the input of the adder 17, the second input of which receives a signal from the output of the integrator, proportional to the integral of the specified performance set on the setting unit 15.

On the comparison device 18, the signal of the load converter is compared with the set value coming from the unit 19 for controlling the mass of the product in the tank 11.

As the product leaves the metering device at external receivers, the signal at the output of load transducer 10 decreases and, when the preset level is reached, the signal comparison device 18 is triggered, generating a command to turn on the clock generator 1, switch 8, integrator 16 and adder 17.

Switch 8, actuation, connects the output of the setting device 19 to the first input of the regulator 9 and the second input of the controller to the output of the adder 17, which summarizes the signals proportional to the mass of the product in the capacitance and 11 and the integrated value of the specified performance set on the performance setting 15. The output signal at the output of the adder 17 is proportional to the sum of the amount of product left in tank 11 and the amount of product that must be unloaded by the feeder 12 from tank 11 during the time interval from the moment the signal comparison device 18 operates.

When the performance of the feeder is equal to the specified value, the signal

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the output of the adder is equal to the signal of the setpoint 19 KOHTpoJTHpyeMoA of the product mass, and the signal at the output of the regulator 9 is stabilized, since the signals at its inputs are equal to each other.

When the performance of the feeder deviates from a predetermined value, which most often happens at the beginning of the dosing cycle, for example, downwards, the signals at the controller input are not equal to each other, i.e. the signal from the output of the adder 17 is lower than the signal from the output of the setpoint 19. In this case, the 5 signal from the output of the adder 14, equal to the sum of the signals of the setting knob 15 and the controller 9, increases, which leads to an increase in the performance of the feeder.

Simultaneously with the inclusion of the clock generator 1, the additional 1 adder 4 receives two signals from one upstream of the adder 17. With a time delay in block 3, the output of the additional adder 4 shows a signal proportional to the rate of change of the signal at the output of the adder 17.

As the performance of the feeder increases, the rate of increase of the signal at the output of the adder 17 will decrease and, at the same time as the performance of the feeder, the specified value decreases to zero. At this, at the output of the additional adder, the signal will disappear and the discriminator 5 will command a command of setting device 6 to reset the integrator 16, the adder 17 and turn on the memory cell 7 to remember the signal of the load-measuring converter 10 and switch the memory switch 8 to connect the memory cell 7 to the first input regulator 9.

From this point on, the process of adding signals in the adder J7 starts from the zero level and, if the feeder performance is equal to the specified value, the signal at the output of the adder 17 does not change and is equal to the signal at the output of the memory cell 7. Regulator 9 when the input signals are equal stabilizes the operation of the drive of the feeder.

In case of small performance deviations, the control of the feeder is carried out by comparing the sum of the signals, proportional to the mass of the unloaded and remaining capacity.

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11 of the product, with a reference in cell 7. With large performance deviations up or down, the installation of a new reference signal in cell 7 can be repeated at the command of discriminator 5.

Claims (1)

1. The method of weight dosing of volatile materials, which consists in sequentially setting the signal proportional to a given mass flow rate at a current time, forming a signal proportional to i the current mass of the product in the tank, feeding the drive of the feeder proportional to a given mass flow , integrate the signal proportional to the specified capacity, summarize the signals proportional to the current value of the mass of the product in the tank and the integral of the given performance, compare Received first total signal with a signal proportional to the upper specified mass value. product and form a correction signal for controlling the capacity of the feeder to stabilize the first total signal relative to the signal proportional to the specified upper mass value of the product in the container, characterized in that, in order to increase the metering accuracy, simultaneously with the stabilization of the first total signal proportional to the upper specified value the mass of the product in the tank, determine the amount of rotation of its deviation from the upper set value at the beginning of the dosing cycle, and at the moment of stabilization of the increments of the deviations, the value of the reference signal, proportional to the current value of the mass of the product in the tank, is stored, which is then compared, c. signal obtained by summing the signals, one of which npouopiLHOHtijifjH is the current value of the mass of the product in the container, l the second is obtained by integration with; A memory signal proportional to a predetermined performance and, based on the result of the comparison, a correction control signal is generated by the feeder for Q stabilizing the sum signal relative to the reference signal. 2, Bulk materials dispenser containing a supply tank with a feeder mounted on a force-measuring converter, an integrator, a switch, a product flow setter, the output of which is connected to one of the inputs of the first drive actuator adder and through the switch with an integrator, the second adder, unit of controlled mass of the product in the supply tank, a comparator device and a controller, the output of which is connected to the second input of the accumulator adder of the feeder, the first input is connected to the unit of controlled mass product In the tank, the second input through the switch is connected to the output of the second adder, the first input of which is connected to the load transmitter, and the second input to the integrator output, characterized in that, in order to improve the metering accuracy, a memory cell is inserted into it , select5 minator, additional adder. 0 a delay unit, two valves and a control clock generator connected to a control input unit with a comparison unit, with the additional adder connected to the output of the second adder by the first input through the first valve, and the second input through the second valve and the delay unit, the output of the additional adder through the discriminator is connected to the control inputs of the switch, integrator and memory cell, the input of which is connected to the force-measuring transducer, and the output through 0 The switch is connected to the controller. ABOUT Fi9.2