SU838391A1 - Crane balance - Google Patents

Description

(54) CRANE SCALES

one

The invention relates to a weight measuring technique and can be used to measure the weight of goods transported by cranes, for example, for weighing a liquid metal in a ladle.

Crane scales are known in which, in order to eliminate the influence of the temperature of the molten metal on the load cells, the latter are built into the crane trolley p ..

However, with a load sensor, not only the weight of the load, but also the weight of the cable is recovered, and when the lift height changes, the weight of the cable weighed together with the load changes, which introduces additional measurement error.

The closest in technical fussiness to the invention are crane scales, containing a force-measuring sensor with an analog-digital converter at the output, a weight display device and a temperature sensor with a system converter at the output {2.

The disadvantage of the device is the presence of additive error due to bias of the characteristic or zero care.

The purpose of the invention is to improve the measurement accuracy.

To achieve this goal, the crane scales are equipped with a series-connected adder and multiplier, the output of the signal converter connected to the inputs of the adder and multiplier through the corresponding scaling amplifiers introduced into the crane scales and the analog-digital converters connected to it, the second input of the adder connected to the analog - a digital converter at the output of a force measuring sensor, and a multiplier output - with a weight indication device.

In the drawing, a block diagram of a crane weigher for weighing molten metal in a ladle is provided.

Crane scales contain force-measuring sensors 1 mounted on the crane's cross member, connected to analog-digital converter 2, the output of which is connected to adder 3. Temperature sensor consisting of temperature-sensitive element 4 installed near force-measuring sensors and signal converter 5 is simultaneously connected to

scaling amplifiers 6 and 7 connected to analog-digital converters 8 and 9, respectively. The outputs of analog-digital converters are connected to adder 3 and multiplier 10. The second turn of the multiplier is connected to the adder, and the output to the display device 11.

Scales work as follows.

The signal from the measuring sensors 1, proportional to the applied load (for example, the mass of liquid metal in the bucket) is fed to the input of the analog-digital converter 2, from the output of which in digital form a signal is fed to one of the inputs of the adder 3, and through the multiplier 10 to the device 11 indications. When the temperature of the load sensors deviates from the nominal temperature caused by the heating of the molten metal in the ladle, the signal from the temperature-sensitive element 4 through the converter 5 simultaneously enters the scaling amplifiers 6 and 7, which produce signals that are equal in magnitude to the additive and multiplicative temperature error of the sensor . When the temperature changes, the output signal of the load cell sensor changes, causing the temperature error j which is determined by two components — additive and multiplicative.

The implementation of these dependencies in scale-amplifiers is carried out by corrective links.

Signals from scaling amplifiers with analog-to-digital converters 8 and 9 are converted into a digital code and are fed accordingly.

adder 3 and multiplier 10, in which corrections for measurement results are entered. The resultant signal from the multiplier output is fed to a weight display 5.

Using the proposed crane scales, it is possible to accurately measure the mass of molten metal in the ladle and to cast the metal Q into molds.

Claims (2)

1. Author's certificate of the USSR 685929, cl. G 01 G 19/18, 1978. 2. The author's certificate of the USSR 531039, cl. G 01 G 19/04, 1975 (prototype).