RU1778467C - Method of determination of vapor content in refrigerant flow - Google Patents

Abstract

Usage: measurement of process parameters of refrigeration units. SUMMARY OF THE INVENTION: when determining the vapor content in the refrigerant stream after the unit has reached a steady state, the microflow to the evaporator is limited by the throttle, the magnitude of this microflow is measured by the sensor, and its signal is supplied to the controller, which also receives the signal from the sensor in the microflow after the evaporator. The controller equalizes the microflows and measures the power of the heat sources installed on the microflows. From the temperature and pressure of the liquid refrigerant, as well as from the boiling pressure, the controller determines the enthalpies from the state tables and continuously calculates the vapor content. Moreover, the accuracy of the calculation depends only on the accuracy of the measurement of micro-streams, power of sources and temperatures and pressures. 1 ill.

Description

The invention relates to refrigeration, in particular to the measurement of various process parameters of refrigeration units.

The aim of the invention is to reduce energy consumption during the heat treatment of the refrigerant stream and to obtain a continuous current value.

The drawing shows a device for implementing the method.

The device includes a compressor 1, a condenser 2, a cold choke 3, an evaporator 4, pressure sensors 5 and temperature 6, liquid refrigerant after condensate, a pressure and evaporation sensor 7, a heat source 8, a flow restriction choke 9 and a flow rate sensor 10. Elements 8 -10 placed on the microflow line allotted to the evaporator, which also placed

temperature sensors 17 after the heat source 8. A temperature sensor 15, a heat source 11, a control valve 12 for the second microflow value, a temperature sensor 16, a sensor for the magnitude of the second microflow 13, an input device for the status table console are located on the line of the second microflow allocated after the evaporator 4 refrigerant 18, a computing control device (controller) 19, a device for reflecting and recording 20 the vapor content and other parameters of the device, temperatures, flows, pressures.

The method is carried out using the device as follows. After the device enters steady state, the latter is completely automatically controlled by the device 19, where state tables from the remote control 18 are entered and which supports the required device mode as measured by X XI

2

Oh x |

no vapor content in the equality of microflows. For this, the throttle device 9 limits the sampling flow to the evaporator 4 of about 0.5% of the main refrigerant flow (about 160 g / s), this flow is measured by the flow sensor 10 and its signal is supplied to the controller 19, which also receives the signal of the microflow detector 13 ( taken after evaporation). The signal of the sensor 10, which is the master for the controller 19, which is compared with the signal of the sensor 13, generates a control signal to the control valve 12. by means of which the micro flow through the sensor. 13 becomes equal to the microflow along sensor 10, i.e. 0.5% (0.8 g / s). The measured temperatures before the source 8 and after the sensors 14 and 17 are 20 ° C and 20.1 ° C, respectively. In this case, the controller increases the power of the source 8 until the output temperature reaches 20.1 ° C and measures the power of the (electric) source, or, which is the same, the heat flux, which is q2 0.9 kJ / s. The temperature is also measured before (by sensor 15) and after (by sensor 16) source 11, which is 20 ° C and 20.1 ° C, respectively. In this case, the controller 19 also increases the power (heat flux) of the source (electric heater 11) until the output temperature exceeds the input by the same preset value of 0.1 ° C (set point) and at the same time measures the power corresponding to this excess, which is qi 0,093 kJ / s. Using the measured temperature and pressure of the liquid refrigerant, the signals of the sensors 5 and 6 at a condensation temperature of 40 ° C, the controller 19 determines the enthalpy of throttling, which is read on the screen of the display 20, and is equal to 131 kJ / kg from its state tables. Using the measured boiling pressure (sensor signal 7), the controller determines the enthalies at zero h0 125 kJ / kg and a single hi 311 kJ / kg vapor content from the state tables. The boiling point is 20 ° C. Further, according to the formula:

X 1 qi. (um bd)

Q2 (hi -h0)

 l

0.093 (311 -131) 0.9 (311 -125)

 1 -0.1 0.9

The controller continuously calculates the vapor content. Moreover, the accuracy depends only on the accuracy of measuring microflows, power sources, temperatures and pressures,

which is not difficult to ensure high enough.

The presented method allows for minimal energy consumption and the simplest measurements of heat flow, temperature and pressure to obtain a continuous value of such a difficult to measure parameter as steam content, the value of which is necessary to ensure the required quality of the process

vaporization, and to ensure reliable operation of compressors carrying out the compression process.

Claims (1)

Using the inventive method allowed to reduce the energy consumption of the source from 18.6 kJ / s in the prototype to 0.993 kJ / s, i.e. almost 200 times, and ensure continuous measurement of steam content, as it is determined by measured capacities, temperatures and pressures, which are measured quickly and simply. SUMMARY OF THE INVENTION Method for determining vapor content in a refrigerant stream by heating a refrigerant stream with a heat source, measuring temperature and determination of vapor content, characterized in that, in order to reduce energy consumption during the heat treatment of the refrigerant stream and obtain a continuous current value the vapor content, organize the microflow of the refrigerant before evaporation with the first heat source and the microflow after evaporation with the second heat source, these microflows are further mixed with the main tray, the temperature at the inlet and outlet of the heat sources of each microflow is measured, the evaporation pressure and the pressure of the liquid refrigerant after condensation, for each microflow, the heat flux of the heat source is increased until the input temperature exceeds the output temperature and the heat fluxes of the sources are measured at the initial moment of this increase, and the steam content is defined as the difference between unity and the ratio of the difference in the enthalpies of a single steam content and throttling multiplied by the heat flux of the first heat source and the difference in the enthalpies of a single and zero vapor content, multiplied by the heat flux of the second heat source.