SU815657A1 - Direct-reading calorimetric power meter - Google Patents

Description

one

The invention relates to a measurement technique and can be used to measure the absorbed power of continuous and average values of pulsed modulated electromagnetic oscillations.

A direct calorimetric wattmeter is known in which the absorbed power is proportional to the temperature difference between the hot and cold thermal sensors connected at the outlet and the inlet of the calorimetric load along the hydraulic line along the mass flow rate of the calorimetric fluid.

The disadvantage of this wattmeter is the limitation of measurement accuracy due to various temperature disturbances in the hydraulic system of the wattmeter occurring when absorbed by the load of electromagnetic energy.

The closest technical solution to this invention is a direct absorbed ms meter containing a calorimetric load connected between cold and hot thermal sensors connected respectively to the inputs of a temperature difference meter, a calorimeter flow meter, a multiplication unit, where the difference signals are multiplied temperatures

and the flow of calorimetric fluid, and measuring device t.

However, during operation of the meter, in the event of a temperature fluctuation of the calorimetric fluid, a dynamic error occurs in the measurement of the temperature difference caused by the finite transit time of the calorimetric fluid from the cold to the hot thermal sensor. That is, any temperature perturbation in the hydraulic system at each time point in an unequal manner affects the readings of each temperature sensor, which causes an error in measuring the temperature difference and, therefore, an error in measuring the absorbed power. This is most pronounced for closed hydraulic systems, when the establishment of a stationary thermal regime in a hydraulic system when supplying or changing the level of absorbed power is one and

for tens of minutes, in such thermal processes, the temperature of the calorimetric fluid varies according to the nv-exponential law.

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

The goal is achieved by the fact that in a direct calorimetric wattmeter contains a calorimetric load connected between cold and hot thermal sensors connected respectively to the inputs of the temperature difference meter, the flow meter of the calorimetric fluid, the output of which is connected to the first input of the multiplication unit, is connected to the output of the temperature difference meter measuring device, additionally entered adder, subtraction unit, delay line, the output of which is connected to one of the inputs of the subtraction unit, etc. The corresponding input and the input of the delay line are connected to the output of the cold thermal sensor, the output of the subtraction unit and the output of the temperature difference meter are connected respectively to the inputs of the adder, the output of which is connected to the second input of the multiplication unit, and the delay time of the delay line is equal to the cold to Hot temperature sensor.

The drawing shows a block diagram of a wattmeter.

The wattmeter contains a calorimetric load 1, connected along the hydraulic path between the cold thermal sensor 2 and the hot thermal sensor 3, which are connected to the input of the meter 4 temperature differences. In addition, the wattmeter also includes a calorimetric flow meter S, an multiplication unit b, a delay line 7 with a delay time t equal to the time it takes for the calorimetric fluid to pass from a cold to a hot sensor, a subtraction unit 8, an adder 9, and a measuring device 1

Electromagnetic energy is absorbed by the flow of calorimetric fluid passing through the calorimetric load 1, while the flow meter 5 determines the flow rate V, which is converted into an electrical signal. The output of the flow meter 5 is connected to the first input of the multiplication unit 6. The temperature difference between the hot temperature sensor 3 and the cold temperature sensor 2 is proportional at constant consumption, the absorbed power j is converted into a temperature difference meter and also into an electrical signal DT, which is fed to the input of the adder 9. The other input of the adder 9 is connected to the output of the subtraction unit 8 / but

the output of the adder 9 is connected to the second input of the multiplier b, the output of which is connected to the measuring device 10. The first input of the subtraction unit 8 is connected to the output of the delay line 7, its other input is connected to the input of the delay line 7 and the output of the cold thermal sensor 2,

The signal from the cold temperature sensor 2, proportional to the input water temperature TO /, enters the input of the subtraction unit 8. The other input of the subtraction unit 8 receives the signal Tor, delayed by a period of time t as it passes through the delay line 7. At the output of the subtraction unit 8, a TOTTQ signal is generated, which is summed algebraically with the main signal q T in the adder 9, if the input temperature of the calorimetric liquid rises , TO - and from the main signal d T is subtracted the correction signal OG-0 6SLI the input temperature of the calorimetric fluid decreases Tyf. T (o, then to the main signal d t is added the value of T TO the corrected difference signal

temperatures d T ± (Tdr. - T) are multiplied in block b of multiplication with a signal V proportional to the consumption of the calorimetric fluid. From the output of multiplication unit 6, a signal proportional to the absorbed power is fed to a measuring device 10, calibrated accordingly.

Eliminating the unequal influence of temperature fluctuations in the hydraulic system on the sensors significantly reduces the magnitude of the dynamic error and at the same time helps to reduce the traditional lack of calorimetric wattmeters a long time to establish readings.

Claims (2)

1. Authors certificate USSR 498566, cl. B 01 R 21/02, 1974. 2. Electronic technology. Seri 11, 1967, no. 3, s. 16-22 (prototype) WITH P