SU765662A1 - Device for weighing in conditions of vibration of loads - Google Patents

Description

The invention relates to weighing equipment and can be used for weighing in conditions of oscillation of loads (on floating vehicles, on cranes, etc.).

The known device containing primary and secondary power converters does not provide the necessary weighing accuracy .10

The closest in technical essence to the present invention is a device for weighing under the conditions of oscillation of loads, containing an autocompensator consisting of a sequentially 5 input circuit, a zero-organ, an output node, a divider, the output of which is connected to the input circuit input, block main and additional power transducers, according to 20 SPOKL23,

The drawbacks of the device are comparatively low, measurement accuracy and difficulty in manufacturing and operation .25

The purpose of the invention is to improve the measurement accuracy and simplify the design.

To achieve this goal, a summing and de jg node has been entered into the device.

voltage coupler, one of the inputs of which is connected to the output from additional power converters through a matching device, others to the output node of the autocompensator, with the inputs of the summation node connected to the output of the main power converters and output of the voltage divider, and the output connected to the second input of the input compensator . FIG. 1 shows the design of the proposed device; FIG. 2 is a block diagram thereof.

The device has a weighing platform 1, based on the main (measuring) power converters 2 (for example, strain gauge power converters), on which measured load 3 of unknown mass T is superimposed. Additional platform 4, supported by force converters 5 (similar force converters 2), is loaded with control load b with constant mass td. Under static conditions, the power converters 5 with the load imposed on the platform are balanced to the zero of the output voltage. The output of the power converters 2 is connected to one of the inputs of the summing node 7, the output of which is connected to the auto-compensator (highlighted in Fig. 2 by the dashed line). An autocomp.nator consists of an input circuit 8, a zero-org on 9, an output node, made, for example, in the form of a reversible counter 10 and a measuring divider 11, which produces a compensating voltage 13 proportional to the mass m in the weighed load 3. Input Voltage divider 12 is connected to the output of additional power converters 5 through matching device 13, and its control inputs are connected to a reversible counter 10 of the autocompensator output node. In addition, the output of the voltage divider is connected to the second input of the summation node 7. Power transducers 2 and. 5 are connected with each other (for example, at the base of the weighing device), in connection with which two loads 3 and 6 experience the same disturbances in the dynamics of movement of the base of the balance. The device works as follows. Under the conditions of the base oscillation, under the action of a weighed load 3 with mass t, a voltage of llx ± AUj arises at the output of the main power converters 2 (, consisting of a constant component proportional to the mass mX and acceleration of free fall, and a component of dynamic disturbance + AUx, which is also proportional to: the mass m and, for example, the acceleration of the oscillating motion of the base of the balance, the resulting voltage can be expressed in terms of the parameters of the balance i, (ui and „„; and „„), where Ufij, and t and mon are constant and variable corresponding stresses The corresponding maximum load on platform 1 with a weight of m Uxo AU) jU;, "is the load factor of the load cell pc, varying from zero (the balance is unloaded) to one (maximum load on the balance), at the output of additional power converters 5 in these Under the conditions of oscillation of the base of the balance, an interference voltage + Uo arises proportional to the effect of the test load 6 with a constant mass m due to the acceleration of the oscillatory movement of the base of the balance. This voltage is supplied through matching device 13 to divider 12 and is divided in proportion to the mass m of the weighed load 3 to the value ± лОо, since divider 12 is connected with a reversible counter 10 of the output node of the autocompensator, the reading of which in this case corresponds to the weighed weight of mass m. Then, the output voltage of the divider is summed up in the node summing IN 7 with the output voltage of the main power converters 2 in anti-phase Jitter ± d U, (. Consequently, the voltage coming from the output of the summation node 7 to the input circuits 8 of the autocompensator will be U, U, ot4Ux ± | U, AUo Ux-U, otfU, (). To suppress dynamic disturbances in the voltage U, arrive at the input of the autocompensator, for any masses t, (weighed load 3, the condition uDf must be met, which is easily achieved with the adjusting coefficient transfer matching devices 7. It follows from the last expression that when changing from zero to one, i.e. when weighing loads over the entire range of weights loads, only the constant component Ux Uxo6e3 of the dynamic disturbance is fed to the input of the autocompensator. The following is a weighing process using a numerical example: It is assumed that the scale is designed for a maximum load of 10 tons and the weight of the weighed cargo is 5 tons, i.e. equal to half the limit reading of the scale. The scales are installed on a vessel with such a roll that the slope of the basis of the scales leads to an underestimation of the scales by 10%. Before placing the load on the weighing platform, the readings of the autocompensator were zero, the transfer coefficient of their divider 12 was also zero. When loading the load, the platform 1 at the output of the main power converters 2 appears, for example, a useful signal of size U X 10 and dynamic disturbance (due to the roll of the vessel) of 1 mV (the sign of the disturbance is negative, as the scales lower readings). In the control cargo path, there is always a signal: the signal of interference due to the ship’s heel and its magnitude already for yes, there is an interference signal due to the ship’s heel and its value already at the output of divider 12 could be UQ 2 mV, if automatic counter 10 was completely aa full. But since before the installation of the load on the platform, the meter readings are still zero, at the output of divider 12, the interference signal will also be zero (/ U X О). The load was now installed on the platform, and the reversible counter began to fill, and the process of compensating the signal at the output of the summation node 7 with the signal Ik taken from the output of the measuring divider 11 began.

the starting time is 11 10-1 9 mV. DR-YoPajut that at some intermediate time, the reversible counter, increasing its readings, reached a reading of 0.25. Now, the input of the summation node 7 receives a signal of interference from the test load of 0.25 X 2 0.5 mV, as a result of which the signal of the compensator will not be 9 mV, but 9 +0.5 9.5 mV. When the counter reaches the reading of 0.4 from the limit at the input of the autocompensator, the signal will later become equal to 9 + 0.4x2 9.8 mV. Finally, when the counter reaches 0.5 from the limit, the signal at the input of the autocompensator will become equal to 9 + 0.5 X 2 10 mV, i.e. the auto-compensator will show the exact value of the weight of the weighed cargo of 5 tons. Here it can be seen that the process of establishing proportionality between the interference signals in both channels is inextricably linked to the weighing process.

If the counter readings change randomly from the original readings of 0.5 to 0.6, the signal at the autocompensator input will become equal to 9 + (0.6 X 2) + 10.2 mV. Since the meter readings were taken to be 0.6, the output of the divider 11 would be a voltage of 12 mV. This means that the input circuit 8 has two voltages: one is 10.2 mV with a plus sign, and the other is 12 mV with a minus sign. The resulting voltage at the output of circuit 8 will be 1.8 mV and the zero-body 9 will change the counting direction of the reversible counter 10 to subtract pulses, i.e. counter 10 will decrease its readings (not increase, but decrease). Even if the meter readings have decreased to 0.501 (i.e., slightly more than a correct reading of 0.5), then in this extremely close (but still greater) reading at the first input of circuit 8 there will be 9 + (0.501 x

2) +10.002 mV, and the compensating voltage at the second input of the circuit 8 will be -10.02 mV, i.e. in this very unfavorable case, it will also be larger than the measured value of 0.018 mV. Therefore, the null authority 9 will indicate the execution of the subtraction operation. Only with a counter value of 0.5, the measured signal will be accurately compensated, and the counter 10 will stop at this position.

Claims (2)

1. USSR author's certificate 185508, cl. G 01 G 1/22, 42 F, 1962. - 2. Patent of France No. 2123226, cl. G 01 G 19/00, publ. 1972 (prototype). S  g tl