SU957014A1 - Device for automatic graduation of thermal converters in dynamic mode - Google Patents

Description

one

The invention relates to thermal measurements and is intended for automatic calibration of thermal converters in a dynamic mode.

A device for automatic calibration of thermoelectric thermal converters in a dynamic mode is known, which contains a low-in-speed electric furnace, switching and separation devices, an exemplary thermoelectric converter, a software temperature controller, a controller, and a two-coordinate recorder 1.

However, this device is characterized by comparative complexity and lack of accuracy due to the lack of possibility of taking thermal inertia into account in dynamic error.

The closest to the proposed by the technical essence is a device for automatic calibration of thermocouples in a dynamic mode, containing an exemplary thermoconverter and switch, connected respectively to the inputs of two thermometric parameter meters, recorder, clock generator, graduated thermocouples connected to the input of the switch . In addition, the device is equipped with a control thermocoupler, a computing device, which includes an electrical analogue of the switchable thermoconverter 2.

However, the known device is rather complicated. The presence of a thermocouple thermoconverter, which should have the same thermophysical properties as an exemplary thermocouple, and the electrical analogue of the thermocouple being converted, reduce the accuracy of calibration, especially in a wide range of temperatures. The disadvantages include the fundamental difficulties of simultaneously calibrating thermocouples of various types, which are caused by the need to have suitable different electrical analogs.

The purpose of the invention is to improve the accuracy of calibration and simplify the device.

The goal is achieved by the fact that the device additionally contains two thermal inertia meters of thermal converters, the inputs of which are respectively connected to the switch output and an exemplary thermal converter, and the outputs

they are connected to the inputs of the thermometric parameter meters, with the output of thermometric meters that are connected to the inputs of the detector, and the clock pulse controller is connected to the clock input of the switch.

The drawing shows 6lo -circuit device.

The device contains cryoetat 1 e located in it: 1E | .K) m 2 for model 3 and calibrated 1 ×) 4 thermal converters, meter 5 of thermometric parameter and meter b of thermal inertia of exemplary thermal converter, switch 7, generator 8 clocks imulyator 10 thermometric1 aaramet, 1 a calibrated thermal transducer, registrator driver P. As thermometric parameter meters 5 and 10, you can use any nromnileynuk) automatic apparatus for measuring sonrottling or direct; ve registrar 11 - punch, tsifronechatayuschee device, caMoiJiiceu. or EVD.

The operation of the device is based on the comparison of the thermometric parameters of the image of the 11th and graduated thermal converters for different times1 1, when their initial temperatures coincide.

The device is working afterwards.

The temperature of the working area, in which the output is calibrated and the image of the thermocouples, is unchangeable, changing the direction of change. The rate of change of temperature is chosen such that the MOJVO disregards the change in the m. Temperature of the operating 30t: h; during the comparison period for one calibrated thermocouple.

The signal from the generator 8 pulses switch connects to the inputs of the meters 9 and 10 of the first graduated thermocouple. When a calibrated thermocoupler is connected, a commutator generates a synchronization pulse that triggers meters 6 and 9 of thermal inertia, which provides an indication of the measurement of thermal inertia of calibrated and reference thermocouples.

The principle of operation of the thermal inertia measure is based on the heating of the thermal transducer by a current pulse and the recording of the time interval during which the value of the derivative of the temperature relaxation reaches a predetermined change. The ratio of the derivative values is chosen such that the time interval of the change is equal to the value of the thermal inertia.

After measuring the values of thermal inertia of a calibrated ital model thermocouple from meters 6 and 9, they form control signals that determine the times of measurement of the thermometric meter.meter thermometers

of parameters 5 and 10, at which the true temperatures of the reference and calibration. most of those | transducers coincide. The first thermometer will be measured, the thermal inertia of which is less. The measured values of the thermometric parameters are recorded by the recorder 11.

After the termination of the first thermocoupler, the commutator switches the remaining thermal converters in series. Onroos.M of the last graduated thermotransformer completes the calibration in the vicinity of the given comparison temperature.

The next signal from the 8mpulse generator causes a repetition of graduated Jipotucea in the vicinity of the next temperature in the village.

The introduction of thermal inertia meters into the device allows us to pin down its TO4iiOCTb and expand its functionality.

Elimination of the control thermocoupler and its connection of c; their wires from the working area lead to an improvement in the metrology of the container's possible capabilities and improves the accuracy of calibration, especially in the cryogenic temperature range. Accuracy is also increased in addition to the fact that the output of intermediate transforms of real heat inertia is equivalent to the equipalent parameters of the control thermal transducer and the electrical analogue of the thermal converter.

Since in the device the thermal inertia of the sample and calibrated thermocouples is directly measured, it became possible to perform calibration in a wide range, including the low temperature region, and at the same time for an unlimited number of different types of thermocouples.

Claims (2)

1. USSR author's certificate number 165327, cl. G 01 K 15/00, 1963. 2. USSR author's certificate No. 657278, cl. G 01 K 15/00, 1976 totip).