SU853409A1 - Automatic batch-type scale - Google Patents

Description

54) AUTOMATIC WEIGHT PORTIONAL

DISPENSER

The invention relates to weight dosing devices and may be applied to automate the dosing of bulk and liquid materials. An automatic weight portioning dispenser is known, containing a metering device with a weight mechanism, the axis of which is associated with a rosin of a resistive sensor connected in an indicator circuit with a resynominal receiver, coarse and precise metering control signal formers 1. This device does not provide high accuracy and not enough reliably. An automatic weighing device is also known, comprising a scale with a pointing device and a selsyn sensor, the rotor of which is connected to the axis of the arrow of the pointing device, a demodulator and a coding unit 2. Its disadvantage is the complexity of the design of the sensor, due to the presence of an additional selnsi-sensor and mechanical transmission between selsyns. The closest technical solution to the invention is an automatic weight portioning dispenser containing a weight mechanism connected to a selsyn sensor having a three-phase and a single-phase winding, the last of which is connected to one of the demodulator inputs, an encoding unit that weighs the portion weight to the inputs which is connected to a three-phase voltage source, coarse and accurate dosing triggers, the outputs of which are connected to coarse and accurate dosing signals, the threshold unit and the differentiator B are known In a given device, the instances of the end of the group & d and exact metering are determined by the amplitude of the voltage on the stator winding of the axle sensor operating in transformer mode. Therefore, the instability of the supply voltage of the coding unit, which forms the voltage on the rotor windings of the selsyn sensor, greatly affects the dosing accuracy. The principle used in this device requires programming not only the weight, but also its additional characteristic. This complicates the design of the coding block,

its management, as well as the logical structure of the circuit, which leads to a decrease in the reliability of the device as a whole. The purpose of the invention is to improve the accuracy and reliability of the dispenser in operation.

This goal is achieved by the fact that the three-phase winding of the selsyn sensor is directly connected to a three-phase voltage source, with the output of the coding unit connected to other inputs of the demodulator, the output of which through the differentiator is connected to the trigger input of exact metering, and through the threshold unit to the trigger input of coarse dosage. Fig. 1 shows a functional diagram of the dispenser described; Fig. 2 shows a voltage chart at the dispenser demodulator output.

The dispenser contains a weight mechanism 1, the pointer of which is mechanically connected with the rosin of the resolver sensor 2. The single-phase winding of the selsyn sensor is connected to the first pair of inputs 3 and 4 of the phase demodulator 5, the outputs of the coding unit 8 are connected to another pair of inputs b and 7 The output of the phase demodulator through the differentiator and the threshold unit 10 is connected to the inputs of the exact dosing and coarse metering triggers 11, 12, respectively, associated with the exact 13 and coarse 14 dosing signal conditioners. The outputs of the three-phase voltage source 15 are connected to the three-phase winding of the selsyn sensor 2 and to the inputs of the coding unit 8.

The dispenser works as follows.

The coding unit 8 allows programming the portion value by setting the initial phase of the output sinusoidal voltage. In the initial state, the triggers 11 and 12 are reset. The start signal includes these triggers, and their output voltages include coarse-14 and precise 13 metering signal drivers. The weight gain and rotation of the rotor of the tele-sensor 2 begins,

In this case, the difference between the initial phases of the output voltages of the selsyn sensor 2 and the coding unit 8 is reduced. The voltage at the output of the phase demodulator 5 changes according to the law described by the diagram shown in FIG. 2.

When this voltage reaches the trigger level of the threshold unit 10 (point a in figure 2), the latter turns off the coarse metering trigger 12. In this case, the driver 14 is turned off.

Kate only the weight of the material to be dosed will reach the value programmed in the coding block (point b in Figure 2), HAPPENSING

a change in the output voltage of the demodulator 5 (segment bv in Fig. 2), the differentiator 9 gives a signal to turn off the trigger 11 of the exact metering. Together with the trigger 11, the precision dosing signal generator 13 is turned off, and the dosing process is terminated.

The width of the precision metering zone is set by setting the trigger level of the threshold unit 10.

In the proposed metering unit, the output voltage of the phase demodulator, which determines the end points of coarse and precise metering, depends only on the difference between the initial phases of the output voltages of the sensor and the coding unit and does not depend on their amplitudes, which increases the accuracy of the metering unit. The linear form of this dependence improves the accuracy of setting the width of the exact metering zone, as well as eliminates the programming of an additional weight characteristic and simplifies the logical structure of the circuit. An additional increase in accuracy is possible when using as a coding device a resolver identical to the resolver sensor, which makes it possible to compensate the influence of the phase imbalance of the three-phase voltage source on the initial phases of the output voltages of the sensor and the setpoint generator.

Claims (1)

Claims of an Automatic Weight Portioning Dispenser comprising a weight mechanism connected to a selsin sensor having three-phase and single-phase windings, the last of which is connected to one of the demodulator inputs, an encoding unit specifying the weight of the portion to which the three-phase voltage source is connected. , coarse and precise metering triggers, the outputs of which are connected to coarse and exact metering signal conditioners, a threshold unit and a differentiator different from TeNf, which, in order to Improving its accuracy and reliability in operation, the three-phase winding of the selsyn sensor: is directly connected to a three-phase voltage source, the outputs of the coding unit are connected to other inputs of the demodulator, the output of which is through the differentiator connected to the trigger input of the exact metering, and through the threshold unit - the entrance of the t.rigger coarse dosing. Sources of information taken into account in the examination 1, USSR Copyright Certificate No. 456211, C. 01 G 13/28, 1970, 2, USSR Author's Certificate 311147, C. 01 G 13/28, 1970. 3, USSR Author's Certificate 347587, class, C 01 G 13/28, 1970 (prototype). V. 5b / g D60 ° fll73 ffCJ77 fl y fff ff & Jf ff S /; 70 e // cpffffa / m / ffffff rrfffloeff ffeff C / 77/7 7uff / 7 7 dcfffcfHHdfV jffff