Method and device operational control of the concentration of the gas phase undissolved gas in the fluid flow

 

(57) Abstract:

Group of inventions relates to measurement technology and is intended for use in production lines of various industries, in particular in the circuits of nuclear reactors. The control is as follows: with a continuous and constant flow of liquid medium through the U-shaped vessel, the "left" part of the resulting physical and mechanical separation of the phases during the time t1in the upper part is the accumulation of gas phase and liquid replacement, resulting in a fall of the liquid level with a certain speed is directly proportional to the volumetric fraction of the gas phase in the coolant dh/dt = k*Cext. The sensor monitors the change in this level, producing an analog signal in the form of a linearly increasing or linearly falling time of the current that is supplied to the preamplifier, the preamplifier this current is amplified in proportion to the ratio k=Q/S, is converted into linearly falling voltage and fed to a microprocessor controller, where by differentiation is converted into a DC voltage directly proportional to the value of the desired concentration, and in the loop and preparation for measurement, through power electronic key control solenoid valve. At the end of the measurement time t1microprocessor controller generates a pulse of duration t2the electromagnetic valve is opened, the return fluid from the right side of the U-shaped receptacle on the principle of communicating vessels flows into the left part of the U-shaped sensor, restoring the level of the liquid in it to original position, simultaneously displacing the gas phase from the "left" side in the coolant flow. After a time t2the valve is closed and the measurement process automatically begins again. Achieved acceleration and increase efficiency control, and sealing of the sample. 2 S. p. f-crystals, 1 Il.

The invention relates to a measuring technique of determining the gas content of the liquid, and solves the problem of operational control of the concentration of the gas phase (dissolved gas) in the fluid flow process circuits of various industries, mainly on the NPU.

There is a method of determining the gas content of the solution by the method of displacement of fluid from the calibrated vessel analyzed the breakdown (Bender O. S., Mahin C. M., Abalkin A. K., Zotov, E. A., G. reports fourth interdisciplinary conference on reactor materials science, so 1, Dimitrovgrad 1996, page 214), which includes operations for supplying and filling of the vessel obezvozhennoy fluid and sealing from the atmosphere, the operation for supplying the sample into the vessel, the operation of the depressurization of the vessel and discharge from the rest of the liquid in the volume not exceeding internal volume of the calibrated vessel, the steps of measuring the volume released in the vessel of the gas phase, the amount of drained fluid and the operation for measuring absolute pressure and temperature in the vessel.

The desired concentration of the gas phase is calculated as the ratio of the volume of the gas phase to the bulk liquid phase, from which the gas phase was separated.

C= Vg273Pc/(VW-Vg)0,1013 Tc, [NCM3/kg],

where Vgthe volume of gas collected in the vessel, cm3;

VW- the volume of drained liquid, cm3;

Pwiththe absolute pressure of the sample in the vessel, MPa;

Twiththe temperature of the sample in the vessel, TO;

- density of fluid, kg/cm3.

The disadvantages of the method are:

- large measuring cycle 0.5 - 1 h;

- reduction of thermophysical properties of the fluid pressure and temperature at 0.1 MPa and K respectively, inevitable because of the presence of operalaboratorio version;

contact of the sample with the atmosphere, unwanted when controlling the gas content in the first contours of the NPU.

These drawbacks are due to the method of determining the specific concentration, i.e., the expression on her through the ratio of the volumes of the gas and liquid phases, to determine which require time-consuming preparatory operations, such as supply and filling, sealing from the atmosphere and depressurization, plums, measurement of the volume of drained fluid.

The aim of the invention is to provide a method of operational control of the concentration of the gas phase in the fluid flow process circuits of various industries by further development of the method of displacing liquid from a container, which consists in the expression of the desired concentration through the rate of displacement of fluid from the vessel.

Mathematically it can be proven that the rate of displacement of fluid from the vessel directly proportional to the concentration of the gas phase. Transform the well-known expression of the concentration of the gas phase over the ratio of the volumes of the gas and liquid phases:

C=VgRwith/VW0,1013 Tc=VgTOn, (1)

where Cthe concentration of the gas phase (the total value of concentration is the origin of the volume of gases to normal conditions;

Vg- the amount of undissolved gas in metered quantity of fluid;

VW- the volume of fluid in metered amount of fluid.

Here

Vg= CVW/Kn, (2)

Express the volume of drained fluid through the coolant flow Q at time t and substituting it into equation (2), we get:

Vg= Cx Q t/Kn, (3)

dividing both side of equation (3) on the cross-sectional area of the vessel S, we obtain the expression:

Vg/S = h =Cx Q t/S Kn, (4)

where h is the height of the liquid column in the "left" part of the connected vessel. Will predifferentiated equation (4) at time t:

dh/dt = CQ/SKn= CKg/Kn, (5)

where Kgis the coefficient of proportionality if the condition Q=const, depending on the flow volume and the geometric dimensions of the vessel.

Kg=Q/S

From equation (5) shows that the concentration of the gas phase solution can be expressed through the velocity of the falling level of the liquid phase in the vessel is displaced by the gas, resulting from physico-mechanical phase separation in a downward laminar flow.

And it allows dalfaz in the vessel;

- replace operations, supply, fill and drain in a single operation-continuous leakage of liquid through the vessel with a constant flow;

- giving the vessel a U-shape, which helps to ensure continuous spilling of coolant and at the end of the cycle "dimension" to restore the liquid level in the vessel to its original position by the method of communicating vessels when performing the operation of "connection" - cycle "preparing for measurement";

- introduction operations "connection", which consists in the temporary connection of the upper parts conditionally "left" and "right" parts of the measuring vessel for equalizing the pressure in both parts of the vessel, opening the way out of the accumulated gas from the "left" part of the vessel, the alignment of the liquid level in both parts of the vessel, displacement residue gas from both parts of the vessel as they are filled with fluid and the removal of this gas in the flow of coolant;

- convert the differentiated electrical signal into a digital code.

Thus, the measurement of the concentration of the gas phase by measuring the rate of fall of the liquid column can reduce the cycle time to almost continuous (e.g., 17), as the speed of the falling column of liquid which/P> A device for determining the concentration of the gas phase of the sample by the method of displacement, (Bender O. S., Mahin C. M., Abalkin A. K. , Zotov, E. A., gas and Chemical monitoring in the loop experiments on the safety of WWER-type reactors. Proceedings of the fourth interdisciplinary conference on reactor materials, so 1, Dimitrovgrad 1996 , page 214), containing a calibrated receptacle with locking devices, of a device for the controlled discharge of the quantity of solution, the device to determine the amount of accumulated gas, and sensors for measuring temperature and pressure of the sample in the vessel. This device is a handheld portable sampler.

It is also known a device for determining the gas content of the solution containing the upper chamber, working on the principle of liquid displacement from the vessel, means for measuring pressure and temperature, a device for the controlled discharge quantities and closure devices (Sen L. I., Sen, A. L., Kuznetsov P. A., the Method of determining the gas content of the solution and the device for its implementation the application 97103407 from 06.03.97, BI 10, including 1, 1999, S. 217).

The disadvantages of these devices are:


- the inability to use the flow aspropotamos version;

contact the radioactive sample with the atmosphere when used on pressure vessels.

These drawbacks are due to the method of determining the specific concentration, i.e., the expression on her through the ratio of the volumes of the gas and liquid phases.

C= Vg273Pc/VW0,1013 Tc, [NCM3/kg],

The aim of the invention is the creation of automated Assembly device that implements the method of rapid determination of the concentration of the gas phase of liquid in the technological paths of different industries, including nuclear power, by setting it directly in the process line and ensure through it a continuous stream of fluid with a constant flow.

This goal is achieved by expressing the desired value of the rate of displacement of liquid from a container

dh/dt = CQ/SKn= CKg/Kn, (5)

and is implemented by a device shown in the drawing and consisting

- out of the vessel U-shaped 1, "left" and "right is controlling the change in the height of the liquid column in the "left" measuring part;

- from the preamplifier 4, amplifying the current sensor generating a signal required polarity;

from the microprocessor controller 6 containing electronic device differentiation 5, which converts the electrical signal into a digital code and generates command pulses that determine the duration of the measuring period t1and the duration of the period of preparation for the measurement of t2;

- power electronic key 7, reinforcing the command pulses of the controller and the control valve;

from the solenoid valve 2, connecting the upper cavity of both parts of the U-shaped vessel at time t2preparation for measurement;

- device pressure control 9 and the temperature 10 of the gas phase in a U-shaped vessel to bring the measurements to standard conditions;

- flow meter 8, controlling the consistency of the sample flow.

The proposed device works in the following way:

- with a continuous and constant flow of liquid medium through the U-shaped vessel, the "left" part of the resulting physical and mechanical separation of the phases during the time t1in the upper part is the accumulation of the gas phase and the displacement W of the volumetric fraction of the gas phase in the coolant

dh/dt = CKg/Kn.

The sensor monitors the change in this level, producing an analog signal in the form of a linearly increasing or linearly falling time of the current that is supplied to the preamplifier;

- in preamplifier this current increases with Kgis converted into a linearly falling voltage and fed to a microprocessor controller, where by differentiation is converted into a DC voltage directly proportional to the value of the desired concentration, and digital code;

the microprocessor generates control signals that specify the duration of the measuring cycle and cycle training to the dimensions through power electronic key control solenoid valve;

- at the end of the measurement time t1microprocessor controller generates a pulse of duration t2at the opening of the electromagnetic valve. When this occurs the following: the electromagnetic valve is opened, connecting both parts of the U-shaped vessel, opening the way out of skipuseroobe gas from the "left" part of the vessel; the pressure in these parts of the vessel is aligned and the return fluid from the "right" part of the U-shaped soudeh vessel are aligned, and as you fill the vessel with liquid to happen displacement of gas from both parts of the vessel and restore the liquid level of the original position;

- after a time t2the valve is closed and the measurement process automatically begins again.

1. The method of operational control of the concentration of the gas phase undissolved gas in the fluid flow, including a supply of the sample in a calibrated vessel, the liquid displacement of the vessel in the gas phase, the control of liquid level, pressure and temperature in the vessel, the concentration of the gas phase, draining, removing the gas phase from the vessel, wherein the inlet of the sample in the vessel U-shaped and removing samples from perform continuously at a constant flow rate, the concentration of the gas phase passes through the rate of displacement of fluid from the vessel by differentiating the electrical signal transmitter, removing the gas phase from the vessel carried out by the method of displacement gas-liquid by temporarily connect the upper parts of the vessel.

2. Device operational control of the concentration of the gas phase undissolved gas in the fluid flow, done, and temperature, controls the level of the liquid, characterized in that it comprises a vessel, a U-shape, the upper part of which are connected through the solenoid valve with power electronic key device level control with analog current output, preamplifier, microprocessor controller, which produces the operation of differentiation, generating command pulses to control the solenoid valve and converts the measurements into a digital code.

 

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