SU1408253A1 - Device for measuring quantity of heat in heat supply system - Google Patents

Abstract

The invention relates to heat engineering measurements. The purpose of the invention is to increase measurement accuracy while simplifying the device. When passing through the flow meter 1 of a certain volume of heat transfer fluid, a signal is received at the input of the generator 2 of the pulses, which is converted into a pulse of stationary duration, which goes to the input of the coincidence circuit 15. The input of the counter 16 receives a packet of pulses, the number of which is proportional to the thermal power. Since the frequency of the packs is proportional to the flow rate of the coolant, the number of pulses recorded by the counter 16 for a certain period of time is proportional to the amount of heat. 1 il. with S (L

Description

The invention relates to heat engineering measurements, and in particular to devices for measuring the amount of heat in heat supply systems.

The purpose of the invention is to improve the measurement accuracy while simplifying the device.

In the drawing the Real circuit Device current shaper, a bridge circuit consisting of two circuits, the first of which includes the resistance of the coolant and the resistance of the coolant, the first 6 and second 7 resistors, amplifier 8, switch 9 polarity of the measuring signal, integrator 10, including a resistor 11, integ. the capacitor 12 and the additional resistor 13, the comparator 14, the matching circuit 15 and the counter 16. I The output of the flow meter 1 is connected to the input of the pulse shaper 2.

The current generator 3 is connected to the supply diagonal of the bridge circuit, the input of amplifier 8 is connected to the measuring one, which is formed by the connection points of resistors 6 and 7 and thermal converters 4 and 5, respectively. The output of the amplifier 8 is connected to the switch 9 polarity of the measuring signal of the bridge circuit. However, the polarity of the measuring signal can be switched by switching the polarity of the current generator 3 in the supply diagonal. The output of the bridge circuit (the output of the switch 9) is connected to the input of the integrator 10. The integrator is made in the operating room with an input resistor 11.

the capacitor 12 is connected in series with the additional resistor 13 and is included in the feedback circuit of the operational amplifier. The input of the comparator 14 is connected to the output of the integrator 10. The first input of the matching circuit 15 is connected to the output of the pulse shaper 2, the second input to the output of the comparator 14, and the output to the input of the counter 16.

The device operates as follows.

The voltage on the measuring diagonal of the bridge is determined by the expression of the amplifier I integrate20 where R _t 4 and R _t 5 - resistance of thermal converters 4 and 5 of resistance, respectively;

- resistance of resistors 6 and 7, respectively;

I is the output current of the current generator 3.

This voltage, amplified by amplifier 8, is supplied to switch 9. Depending on the state of comparator 14, switch 9 multiplies the input voltage by +1 or -1. The voltage from the output of the switch 9 is supplied to the integrator 10. Integration of the input voltage continues until the voltage at the output of the integrator 10 reaches the upper level of the operation of the comparator 14. The latter is triggered, the voltage at its output changes sign and changes the state of the switch 9, after which the direction of integration is changing. Integration continues until the voltage at the output of the integrator reaches the lower level of operation of the comparator 14.

R6 = R7 ^! -41a the input of the matching circuit 15 receives pulses of frequency • to

- ___ ~ ARf, 4 + BR _t -5 + C ¹⁴ 'ϋχ - response level of the comparator,

A, B, C - constant coefficients, the values of which depend on the values of the resistances R6, R11 and R13 of the resistors 6, 11 and 13 where respectively η

^In “R6

U3_.

R11 ’

C = 8U _K

K is a coefficient depending on the parameters of the circuit elements.

The value of the resistor 12 is selected 5 depending on. calibration characteristics of thermal converters 4 and 5 of resistance and parameters of circuit elements.

Pulses of frequency f arrive at 10 the first input of the coincidence circuit 15. When a certain volume of coolant passes through a flow meter 1, a signal is received at the input of the pulse shaper 2, which is converted in it into a pulse of stable duration, which is supplied to the second input of the matching circuit .15. At the input of the counter 16 receives a packet of pulses. The number of pulses in the packet 20 is proportional to the thermal power. Since the repetition rate of the packs is proportional to the flow rate of the coolant, the number of pulses N = S1 Ify recorded by the counter 16 for 25 a certain period of time is proportional to the amount of heat.

Claims (1)

Claim The device for measuring the number of. heat in heating systems, comprising a flowmeter with a frequency output connected to the input of the pulse shaper, a bridge circuit with a current power source, a polarity switch of the measuring signal and resistance transducers of the incident and reverse flows, a matching circuit, the first input of which is connected to the output of the pulse shaper, and the output is with the input of the counter, an integrator whose input is connected to the output of the bridge circuit, a comparator whose input is connected to the output of the integrator, and the output is with the second input ohm of the matching circuit and the control input of the polarity switch of the measuring signal of the bridge circuit, characterized in that, in order to improve the measurement accuracy while simplifying the device, the resistance transducer of the incident and reverse flows are connected in series and connected to the supply diagonal of the bridge cxew, and in series with the integrator capacitor additional resistor.