SU769339A1 - Tracer heat flowmeter - Google Patents

Description

profile, therefore, in the registrar's zone, it already has the form shown by the dotted line (Fig. 1), and the mark length increases to / l, thus, the speed is limited, since the feeding of the next mark is possible only after time t, at the moment when tag temperature will be less than the threshold temperature T, T ..

Compensation of the indicated label deformation is carried out by installing an additional recorder at a distance equal to half the initial label length.

/ m

where WB is the velocity value on the flow axis, corresponding to the upper limit of the measured flow range; / „, Is the length of the heating section, is the pulse (work) time of the radiator; / „- the initial label length.

The choice of the distance L as the base distance between the main and additional thermal receivers is due to the fact that the maximum temperature falls in the middle of the label, and the position of the maximum temperature relative to the leading edge remains almost unchanged during the whole time of life and remains equal to L.

The rascometer contains a control unit /, a source of heat meters 2, markers 5 and 4, a measuring unit 5, an integrating unit 6, a time counting unit 7, a functional unit 8, an adder 9, a meter 10, a measuring instrument U / and a branch pipe 12.

The flow meter works as follows. The control unit / periodically turns on the source of heat marks 2 by supplying rectangular pulses with a constant frequency to the power supply circuit of the source of marks 2. As non-contact sources of heat marks, you can use microwave, RF or IR emitters.

The flow rate is determined by measuring the time of movement of the label from the point of its entry into the stream to the first (along the current) recorder 3. The time is recorded as follows. The control impulse from the control unit / switches on the MieTOK 2 iStoc and starts the time counting unit 7. The countdown time unit is turned off by a signal from the recorder 3 at the moment of fixing the mark.

In block 5, the signals from the main 5 and additional 4 recorders are summed up.

The output signal, which is the difference between the signals from the recorders 3 and

4, due to the installation of an additional thermal receiver at a distance L from the main one, has the form shown in FIG. 2. The following tag may already be submitted.

; c + 2L

W

 eleven

where WH is the value on the flow axis, corresponding to the lower limit of the measured flow range, with m 4; t, because / „2L; t - has a well-defined value; x is the distance from the radiator to the recorder.

The output signal from block 5 is continuously integrated by the integrator 6 and is measured by the measuring unit 10. At 1 moment, when the difference between the signals from the recorders 5 and 4

equal to zero, the output signal of the meter 10, which is a function of flow and composition, is compared in the adder 9 with the reference signal, which is generated by the functional unit 8.

The magnitude of the reference signal is equal to the integral temperature difference in the recorders area at a constant initial medium composition for the flow values obtained in block 7.

The difference between the reference signal and the measured one, obtained at the output of the adder, is functionally related to the composition of the measured medium.

Cumulative Motion Time

from the source to the recorder and the composition of the measured medium, allows obtaining the mass flow rate recorded by the device 11.

Claims (2)

1.Katys G.P. Systems of automatic control of velocity and expense fields. M .., “Science, 1963. 2. USSR Author's Certificate N ° 605-096, cl. -G 01 F 1/70, 1976. FSh.2