SU773459A1 - Apparatus for measuring heat-sensor heat inertia velues - Google Patents

Description

one

The invention relates to a measurement technique and is intended to measure the parameters of the exponential processes in heat engineering measurements.

A device for determining the thermal inertia index of thermal sensors is known, in which the derivative of the signal of the thermal sensor 1.10 is used to increase speed.

The drawback of the device is the MSA accuracy of measurement, due to the fact that the result is determined by the absolute value of the derivative with the help of an amplifier with a nonlinear expo-sure characteristic, controlled by voltage.

The closest to the technical essence of the invention is a device for measuring the thermal inertia index 20 of temperature sensors, comprising a series-connected temperature transducer and a differentiator, a comparator connected by one input to the output of differentiator, and the recorder 2,

However, such a device does not provide a sufficiently high measurement accuracy, since the result is non-linear, transcendental 30

function of thermal inertia indicator of a thermal sensor.

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

The goal is achieved by introducing into the known device a null organ, the input of which is connected to the output of the temperature converter, and the output to the control input of the first memory block connected by the information input to the output of the differentiator and through a shifting chain connected to another input. the comparator, and the second memory block, the information and control inputs of which are connected respectively to the outputs of the temperature converter and the comparator, and the output to the recorder.

FIG. 1 is a block diagram of the described device; in fig. 2 - timing diagrams, explaining the principle of its work.

The device comprises a temperature converter 1, a differentiator 2, a null organ 3, a first memory block 4, a bias circuit 5, a comparator 6, a second memory block 7, a recorder B.

Claims (2)

The device works as follows. When a temperature sensor is placed at a constant temperature, its temperature and, accordingly, the output signal 4 - ((t) of the temperature converter 1 change according to the exponential law 4Ct)). (1) where and is the value of the output signal of the temperature converter before the beginning of the transition process; n is the value of the output signal of the temperature converter after the end of the transient process; E. is an indicator of thermal inertia of a thermal sensor; t - time At time t, the output signal of converter 1 reaches the zero-left level, the zero-organ J triggers and fixes at the output of the first memory block the value of the derivative at the point t, which is transmitted to the input comparator through the bias circuit and shifted by U2. In Fig. 2). At the second input, the com parator 6 derivative arrives unchanged (curve n in Fig. 2). At time t. the signals at the inputs of the comparator 6 are compared, the comparator operates and records in the second memory block 7 a sample, which is recorded by the recorder 8, as a result of the measurement. value, (t is directly proportional to the thermal inertia index t of the thermal sensor. Indeed, taking into account the equivalent recording of expression (1) using the derivative and, (t), for the values of the function P., (t) in time t, and t. we obtain ou -u; tt,) - t U). г (Reading the expressions (2) one by one from the other, we obtain Uo - 4C4) ,, u; (4). (3 Since the comparator 6 is triggered when the conditions are fulfilled. (It immediately follows from (3). See. The use of this device allows to increase the measurement accuracy of the thermal inertia of thermal sensors by four times. The proposed device has good manufacturability, its setting is selecting the bias voltage of the bias circuit in accordance with the scale of the registering instrument, the constant thermal inertia meter is easily implemented on simple elements that do not require individual adjustment. A device for measuring the thermal inertia indicator of thermal sensors, containing a series-connected temperature transducer and a differentiator, a comparator connected by one input to the output of the differentiator, and a recorder, differing from the fact that, in order to improve the measurement accuracy, a null-organ is entered into it, connected to the output of the temperature converter, and the output to the control input of the first memory block connected to the differentiator, and through a shifting chain connected to the other input of the compa ora, and a second storage unit, information and control inputs connected respectively to the outputs of the temperature transducer and a comparator, and an output - with a registrar. Sources. Informations f taken into account in the examination. 1. USSR author's certificate W 525862, cl. G 01 K 15/00. 2. USSR author's certificate number 456157, cl. G 01 K 7/14, 04.11.72 (prototype).