SU586330A1 - Heat flow meter - Google Patents

Description

the device 16, to the other input of which is energized from the heater 5. At the output of the device 16, a measuring device 17 is turned on.

The flow meter works as follows.

With the help of setting devices 10 and 13, the absolute temperature of measuring 1 and heat insulating 2 sections is set independently and independently of each other and is maintained continuously at a predetermined level during the operation of the flow meter. The flow of the controlled medium entering the measuring section 1 cools the thermal sensor 6, the signal of which in circuit 8 is continuously compared with the signal of setpoint 10. The error signal from circuit 8 through amplifier 11 controls the amount of current in heater 3 so that the latter changes its temperature in the direction of elimination mismatch.

When the flow rate decreases, the temperature sensor 6 overheats with heater 3 and sends a signal to circuit 8 that exceeds the signal of setpoint 10. As a result, the output of circuit 8 changes the polarity of the signal, which causes a change in current in heater 3, its temperature decreases even at equilibrium can be equal to a given. At the moment of equilibrium, the power in the heater 3 is proportional to the measured flow rate, but is not equal to the power consumed by the controller, which requires separate measurement.

In the proposed device, the power in the heater is varied by means of a multiplier-dividing device as the product of electrical quantities proportional to the current value and voltage by the formula ./.

The further work of section 1 occurs in accordance with the above description in the range of a given temperature.

Temperature variations of the main section

1 due to the heat insulating inserts 5 and the absence of electrical connections between the mp 3 and 4 heaters do not affect the operation of the temperature control device of the heat insulating section 2, which responds only to a change in the ambient temperature.

When the ambient temperature decreases, the heat transfer coefficient of the heat insulating section 2 increases, the thermal sensor 7 is also cooled through the measuring circuit 9, the setting device 13 and the amplifier 14 controls the current in the heater 4, restoring its temperature setpoint.

When the temperature rises, the temperature sensor 7 overheats through the measuring circuit 9, the setpoint 13 and the amplifier 14 reduces the current in the heater 4, returning the circuit to an equilibrium position.

Since thermal sensors 6 and 7 do not have electrical and thermal connections between themselves, the temperature of the measuring and heat insulating sections can be set not only different but also equal and maintained

in the process of working with the required accuracy independently of each other.

The equality of the temperatures of the measuring and heat insulating sections determines the absence of heat losses, which contributes to an increase in the accuracy and reliability of flow measurement.

Claims (1)

Invention Formula A heat flow meter containing its measuring and heat insulating section with temperature sensors, a temperature adjusting device for the measuring section with a power source, and a measuring circuit, characterized in that, in order to increase the accuracy and reliability of the measurement, the heat insulating portion is provided with a temperature control device.