RU1835309C - Gas mixing and proportioning device - Google Patents

Abstract

Usage: the invention relates to the field of dosing, namely gas dispensers, and can be used for proportional mixing of two gases. Essence: the device contains diaphragms 1.0 installed in the supply pipelines of constant cross section in front of the mixer 10. At its output there is a dispenser 14 controlled by an electro-pneumatic valve 15. Behind the diaphragms 1.0, gas reducers 1.1 and 1.2, adjustable chokes 2.1 and 2.2 s are installed in series in front of the mixer. actuators 3.1 and 3.2, behind which pressure sensors 4.1 and 4.2 are placed in each highway with amplifiers 5.1 and 5.2 connected in series, dispersion calculators 6.1 and 6.2, the outputs of which are connected to the synchronized synchronizer flows 7. And the output from it is connected to the software comparator 8, the outputs of which are connected to the blocks of the correcting circuits 9.1 and 9.2, which control the drives of the chokes 3.1 and 3.2. An additional pressure gauge 4.3 with successively connected amplifier 5.3, calculator 11, and comparator 12, the output of which is connected to drive 3.3 of adjustable throttle 2.3 installed at the output of mixer 10, is placed on the outlet pipe of dispenser 14; a time sensor with timer 13 is connected to an electropneumatic valve 15 pneumatic metering drive-14 and to the drive of adjustable throttle 3.3. 1 ill. YO 00 CA) SP IS IS

Description

The present invention relates to the field of dosing, namely gas dispensers, and can be used in the chemical, gas and metallurgical industries for proportional mixing of two gases as an independent device, or as an independent unit of a complex production plant, production line or automatic machine .

The purpose of the invention is to increase the accuracy of gas mixing and metering within a predetermined range.

This goal is achieved in that the device contains diaphragms installed in the supply piping in front of the mixer, at the outlet of which there is a metering unit controlled by a pneumatic drive, and behind the diaphragms there are additionally gas reducers installed in front of the mixer, adjustable chokes with actuators, behind which pressure sensors are placed with series-connected amplifiers, dispersion calculators, the outputs of which are connected to the synchronized flow comparator, and the output of the latter is connected to grammnomu comparator, outputs of which are connected to the correcting circuit units, actuating drives chokes. Moreover, a pressure sensor with a serially connected amplifier, calculator and comparator, the output of which is connected to an adjustable throttle drive installed at the mixer output, and a time clock with a timer controlling the electro-pneumatic valve of the dispenser are additionally placed on the inlet piping of the dispenser. Formulated distinctive features of the proposed solution achieve the objective of the invention - improving the accuracy of mixing gases and metering the gas mixture. Improving the accuracy of gas mixing by the criterion of minimum flow dispersion, and dosing by the criterion of minimum standard deviation of pressure is based on the dependence of the dispersion of the synchronized parameter in the supply line. In FIG. 16, as an example for air, the functional dependences of the dispersion of the flow rate DQ on pressure are shown, obtained by processing the set by implementing Q (t) and calculating the values of the correlation functions. An analysis of the obtained dependences of the variance of the controlled parameter on pressure for systems operating in different but statistically stationary modes showed that for each fixed value of the position of the flow regulators, changing the outlet pressure, the dispersion of pressure DP f (P) or flow rate DQ f can be changed (P), and hence their root mean square. practical deviation and, therefore, to achieve its minimum.

The essence of the proposed solution is explained in the drawings. Figure 1 presents a block diagram of a device.

0 The device (Fig. 1) has gas reducers 1.1 and 1.2 installed at the inlet of the supply pipelines, connected respectively to adjustable throttles 2.1 and 2.2, and the outputs from the chokes

5 are connected to the mixer 10. The inductors are connected by clutches to the actuators 3.1 and 3.2. At the output of the adjustable chokes 2.1 and 2.2, pressure sensors 4.1 and 4.2 are installed, respectively connected to the amplifiers 0 lm 5.1 and 5.2, which are respectively connected to the calculators 6.1 and 6.2. The output signals from the amplifiers, converted into DC signals, are supplied to the calculators 6.1 and 6.2, respectively

for calculating variances

AIS costs and DQ2. To determine the law of the change in the cross-section of the pipeline - the movement of adjustable chokes - the calculators 6.1 and 6.2 are connected to the controller of 7-synchronized flows, where the calculated dispersions of the flow rates of the AHR and DQ2 are compared. The comparator 7 is connected to the software comparator 8, where the result is compared with

5 by the allowable (or desired) variance deviation value for each channel. The sign of deviation and the number of adjustable throttle are determined. Each of the variance calculators may contain,

0 for example, the quadrator and the current averager connected in series, and the calculator of the mean square value of the integral law, and if synchronization is performed according to the 5 m criteria related to the standard deviation, the integrator, averager, adder, quadrator and the second averager are connected in series. The outputs of the comparators 8, respectively, are connected to

0 to correction blocks 9.1 and 9.2, where the control law, for example, the first and second derivatives of the mismatch, is taken into account. The outputs from the blocks of the correcting circuits 9.1 and 9.2 are respectively connected to the drives 3.1 and 3.2 of the adjustable chokes 2.1 and 2.2.

At the output of the mixer 10, an adjustable throttle 2.3 with a drive 3.3 is installed in series, a dispenser 14 with a pneumatic drive 15 connected to a timer and a timer 13. At the output of the adjustable throttle 2.3, a pressure sensor 4.3 with an amplifier 5.3 is installed. to the output of which the calculator 11 is connected in series. The comparator 12. The outputs of the calculator .12 and the time dial with a timer 13 are connected to the drive 3.3 of the adjustable throttle 2.3.

Gas reducers 1.1 and 1.2 for their adjustment have pressure gauges installed at the inlet and outlet. Gearboxes typically operate over a wide pressure range. Depending on the energy capabilities of the supplier and the needs of the consumer, the operating range of the gearbox may be limited by the reduction limits: 0-1; 0-10. 0-20 kgf / cm2, etc. In direct / reverse gearboxes, some pressure fluctuation is observed which reaches up to 1% of its nominal value, which naturally leads to fluctuation and flow. This eliminates the possibility of using it in precision systems without additional smoothing devices. The possibility of using gas reducers of various operating ranges in this technical solution has allowed expanding the scope of the proposed solution. They are well known. Produced by domestic industry.

Adjustable chokes 2.1 and 2.2, 2.3 with drives 3.1, 3.2, 3.3 are well known. As an adjustable throttle, for example, an accurate motor gearbox is used, and as a drive, PIRS (pulse control drive) is used. PIRS is connected to the engine’s precision gearbox by a coupling. This unit is manufactured by the domestic industry and used, for example, in the LRE on 8K51 rockets (see, for example, Technical description of the 8K51 rocket. Engine section), the PIRS rotates the adjustment screw of the engine’s precision gearbox by +1 revolution, and the precise motor reducer here plays the role of a throttle, providing a high reduction accuracy of 0.35% of the nominal value.

Pressure sensors 4.1,4.2,4.3 with amplifiers 5.1, 5.2, 5.3 in the proposed solution can be used of any type. The author used a DD-10 induction-capacitive sensor with an ID-1 amplifier. The reliability and reliability of the measured parameters have been tested many times.

Calculators 6.1. 6.2, 11 are known.

Comparators 7. 8, 12 are known. They are made, for example, in the form of analog devices.

Blocks correction circuits 9.1 and 9.2 are known. They are reinforced by amplification units, the latter can be structurally included in these circuits.

5 Mixer 10, dispenser 14 with pneumatic actuator 15 are well known.

The time clock with a timer 13 are made in one housing. A time clock is a part of an automatic controller by which a desired exposure time value is set. The transmitter sets either a constant value of the exposure time or a variable that can be changed according to a certain law, i.e.

5 software regulation. In the first case, the setter sets the exposure time to the appropriate position by hand, in the second - the timer automatically changes during the adjustment process

0 mechanism with a template having a profile corresponding to a given mode. Time clock and timer are known.

The operation of the device. The operation of the device is based on concrete examples of mixing 5 gases and dosing a gas mixture. Gas displacement and dosing are necessary in the chemical industry based on synthetic production. For example, the basis of the method for producing ammonia is the synthesis of nitrogen and hydrogen from elements. At present, the nitrogen industry is equipped with plants with a wide range of energy parameters; pressure and temperature. As an example, consider the production of a nitrogen-hydrogen mixture in the following mode: obtaining a gas mixture with 80% ammonia at a temperature of + 200 ° C and a pressure of 100 kgf / cm. Getting

0 equilibrium gas mixture at the specified pressure and temperature, i.e. mixtures of stoichiometric composition containing 3 volumes of hydrogen per 1 volume of nitrogen, which corresponds to the ratio of molar fractions

5 MH2 / M (H2 + N2) 0.75, The indicated ratio of ingredients is provided by the system setting. To do this, open the valves in the supply lines x and use the diaphragms 1.0 to set the desired flow rates. Gas reducers 1.1 and 1.2 are adjusted to a pressure of 100 ± 0.5 kgf / cm according to pressure gauges installed at their inputs and outputs. The instantaneous flow rates of hydrogen and nitrogen are measured using flow meters with a fixed constant pressure drop. In this case, they represent adjustable chokes 2.1 and 2.2, through which the established flow rates of gases pass: hydrogen VH2 and nitrogen VN2. The measured gas consumption in this case for each line is determined by the expressions:

- for iodine

Sn2 0.465 pH2 / (273 + tn) VH2:

- for nitrogen

GN2 0.465 Rm2 / (273 + IN) VN2, where / H2 M Vu2 are the volumetric flow rates of hydrogen and nitrogen; PH2 and PM2 are the pressures of hydrogen and nitrogen, respectively; gn and T.N - temperature in ° С.

It can be seen from the above expressions that the average value of the volumetric flow rates of the ingredients and their temperatures are approximately constant. The most pulsating quantities, determining mainly the accuracy of the measurement, are instantaneous pressure values. Therefore, to increase accuracy, the instantaneous pressure values are measured by sensors 4.1 and 4.2, amplified by amplifiers 5.1 and 5.2, and the data are supplied to dispersion calculators 6.1 and 6.2, respectively. When synchronizing the flow over the dispersion, both the dispersion of its instantaneous and integral values are calculated. The synchronization is carried out by changing the pressure in each of the discharge lines, respectively, by changing the flow rate using adjustable throttles, realizing a pattern similar to that shown in Fig. 16. To determine the law of variation of the cross-section of the throttle, the signals from calculator 6.1 and 6.2 are compared with each other using a comparator 7 , and the result obtained is compared in the comparator 8 further with the allowable or required dispersion deviation value for each channel. In this case, the sign of deviation and the number of the deferred throttle are determined. The required value of the total dispersion DQo6Tp is supplied to the input of the comparator 8 if the supply of the same name ingredients is synchronized, or the value (as in the case under consideration) DQiTpn DQjTp if the supply of unlike ingredients is synchronized: hydrogen and nitrogen. The signals from the output of the comparator 8 are supplied to the correcting circuits 9.1 and 9.2, where the synchronization law is taken into account, for example, the first and second derivatives of the mismatch and then, using the drives 3.1 and 3.2, the reactors 2.1 and 2.2 are driven. passing gases into the mixer 10. In the present case, the mixer is a contact apparatus or a synthesis column, and the proposed device can be used here as a unit of a complex production plant.

The gas mixture is dosed by minimizing the deviation of the current mean square pressure value from the predetermined value. To this end, the instantaneous pressure value is measured continuously at the output of mixer 10 by a sensor 4.1, a signal from which is supplied in the form of an electric voltage to amplifier 5.3 and calculator 11. In case

0 control is carried out to minimize dispersion, taking into account the quadratic average pressure value. The signal from the calculator enters the comparator 12, where it is compared with its required value stored in the memory of the comparator. The mismatch signal generated in accordance with the selected control law is fed to the drive 3.3 of the adjustable interrogation 2.3, which passes the mixture to

0 to the dispenser 14, which is controlled by the pneumatic actuator 15. The time setter with timer 13 sets the type of dispensing: periodic or continuous, as well as the dispensing time by supplying a signal to the pneumatic actuator 15.

The technical and economic effectiveness of the proposed solution is visible from the results of a comparative analysis with the base one. The proto type is chosen as the basic solution. The proposed solution has the following advantages:

The device for metering the gas mixture is precision, because when mixed with ingredients, it satisfies

5 requiring a minimum deviation of the variance from a predetermined value, and dosing is carried out by minimizing the deviation of the current mean square pressure from the predetermined value;

-dosing the metered gas mixture into the receiver is independent of the barometric pressure and pressure in the receiver;

5 - the proposed device makes it possible to take into account the average value of pressure, so it is possible to regulate the pressure to a minimum of its standard deviation from the set value;

Claims (1)

0 Claims A device for mixing and dosing a gas mixture containing the first and second inlet and outlet pipelines, each of which is installed 5 a diaphragm, a gas reducer, an adjustable throttle and pressure sensors installed in front of the mixer, at the output of which a third pressure sensor is installed, the inputs of the mixer are connected to piping inlets, characterized in that that, in order to increase the accuracy of the concentration of the mixture and its metering, it additionally contains first, second and third drives, amplifiers, calculators, a third adjustable choke installed after the mixer on the outlet pipe, the first and second comparison elements, the comparison program element, the first and the second corrective circuits, metering units with pneumatic drive installed after the third adjusting throttle on the outlet pipe, and a timer, moreover, on each inlet pipe orifice, gas reducer, adjustable throttle, pressure sensor, outputs of the first and second pressure sensors through the first and second amplifiers and calculators, respectively connected to the first and second inputs of the first element of comparison, the output of which is connected to the input of the program element of comparison, the first and second outputs of which through the first and second correction loops are respectively connected to the control inputs of the first and second drives, mechanically connected to the first and second adjustable throttle mi exit the third pressure sensor through a third amplifier and calculator is connected to the third comparison element, the output of which is connected to the control input of the third actuator, mechanically connected to the third adjustable valve, the first timer output is connected to the pneumatic metering device, the second is the control input of the third drive.