SU828079A1 - Automatic burette - Google Patents

Description

made in the form of an optical impulse system that includes a disk-shutter 4 placed on the driving screw 3 of the drive 2, the radiation source 5 and the light receiver 6.

The light receiver 6 is connected to the second input of the account correction unit 7, the control inputs of which are connected to the output of the correction factor input unit 8. The control input unit 8 includes a control device 9, an adder 10, a converter 11 into a code, an encoder 12. The output of the account correction unit is connected to the input of an electronic pulse counter 13, the output of which is connected to the input of the programmable driver 14 2. The burette has a distribution valve 15.

The meter 16 produced by the metering device 1 has real dimensions (outer diameter) smaller than the limit, specified by the technological tolerance. In the process of factory or laboratory calibration, the test dosing determines its deviation from the size limit in percent, and this correction is entered into the account correction input unit 7. The disc obturator 4 is made with a number of holes (grooves), proportional to the flow rate of the liquid in the metering device 1, which has a maximum positive tolerance.

Automatic burette works as follows. The actuator 2 reports a reciprocating motion to the rod 16 of the metering device 1. Moving upward, the rod through the distribution valve 15 displaces from the vessel of the metering device 1 volume of liquid equal to the true volume of the moving part of the brush. The disc obturator 4 placed on the driving screw 3 of the actuator 2 is rotated to form pulses using a pair of radiation source 5 and a light receiver 6, which are fed to the input of the correction unit No, and from its output to the counter input 13. The number of pulses counted by counter 13 Is a measure of extruded oem. During operation of the device, the account correction unit 7 will automatically reduce the number of pulses passing from the light receiver b to the input of the counter 13, thereby compensating for the deviation of the dimensions of the rod of the metering device 1.

to correct the systematic error occurring when preparing the dosing solution, it is determined as a percentage of its deviation from the calculated value, and the correction will be entered into the correction correction input node 7 equal to the sum (taking into account the sign. OW) of the dosing device 1 and the preparation error of the dosing liquid .

The billing correction node 7 operates in such a way that the number of pulses that have passed from the light receiver 6 to the input of the counter 13 is determined by the state of its controlled inputs, information on which is received in a certain code, since the number of pulses Q KQi arrives at the input of the electronic counter 13 where QI is the number of pulses at the input

account correction node; K - correction factor specified by the input unit of the correction factors, and.

The correction coefficient input node 8 is a converter of the numerical value of the coefficients in

code.

The correction factor input unit 8 comprises a control device 9, for example, switches for deviations of the sizes of the rod Ki and titration correction.

solution Cg- The device should be calibrated in percent, for example, with schchom 0.1%. To enter Ki Kz into the correction node 7, it is necessary to sum both coefficients taking into account the sign of the coefficient

correction of the titrating solution (K Ki + K2), for which serves the adder 10 and the converter 11 to the code corresponding to the code of the inputs of the account correction node. The conversion operation is performed by the encoder 12.

The software driver 14 serves to control the end of the dosing process when the volume is reached.

The introduction of additional nodes (the account correction node and the correction coefficient input node) allows, in mass production conditions, to go from individual selection of discs-shutters to

their serial production and installation of the division factor in the process of adjustment and calibration, which makes the instruments cheaper, increases their accuracy. This device allows replacement.

stocks in consumer conditions. The introduction of the correction of the titrating solution allows to increase the labor productivity by reducing the processing time of the analysis results, eliminate errors possible in

processing result.

The company made prototypes of the described device. The glass slides are made with an ic tolerance of ± 20 microns (previously used with a tolerance of +5 microns, which

greatly simplified the process of their manufacture). This device allowed us to easily calibrate the stock to an accuracy of 0.2-0.5% dosed. When changing the rod to different volumes of dosing, the calibration operation is reduced by 1.5-2 times.

The digital introduction of a titer correction factor reduces the time for post-processing of results by 20–30% and reduces the likelihood of subjective errors.

Claims (2)

1. Karanov A. Century and other Titrometers. M., “Mechanical Engineering, 1973, p. 151, 152. 2. USSR author's certificate number 637670, cl. G 01N 31/18, 1977 (prototype). 15