SU773474A1 - Apparatus for automatic sampling of gas from gas flow - Google Patents

Description

(54) DEVICE FOR AUTOMATIC SELECTION OF GAS SAMPLES FROM A FLOW

one

The invention relates to technical means for the qualitative analysis of gas mixtures, in particular to gas sampling devices from a stream, and can be applied in the chemical, petrochemical, metallurgical and other sectors of the industry.

An automatic sampling device is known that is designed to operate under the conditions of sampling gases containing polymerizable products, consisting of inert gas throttles and the mixture being analyzed, an inert gas pressure regulator, a pressure regulator of the mixture being analyzed, and a unit for maintaining the pressure ratio on the throttle x 1.

The closest to the technical essence of the invention is a device for the automatic sampling of gas from a stream, comprising a sampling device, inert gas flow rate controllers and the mixture to be analyzed, and an inert gas supply line 2.

A disadvantage of the known device is the low reliability associated with the unsatisfactory stability of the dilution of the gas being analyzed with inert, due to the instability of the operation of the pneumatic generator, as well as with the failures of the pulse metering device.

The purpose of the invention is to increase the reliability of the device by eliminating the instability of diluting the analyzed gas with an inert gas.

This goal is achieved by the fact that the device is additionally equipped with an electric pulse generator with adjustable duty cycle, an pneumoelectric alternator, an electropneumatic converter, a normally open valve with a nozzle, a normally-closed inert gas discharge element and a blocking valve, while the input of the electric pulse generator is connected to a pneumatic electric generator AC, and the output is with an electropneumatic transducer, the pneumatic input of which It is connected with the output of an inert gas flow controller and a deaf chamber of a normally open valve, and a pneumatic outlet with flow chambers of a normally-closed inert gas reset element and a normally-open valve, the nozzle of which is connected to the deaf chamber of a normally-closed reset element and the control inlet of the sampler, connected by its output through the blocking valve to the flow controller of the analyzed mixture, and the control chamber of the blocking valve is connected to the inert gas supply line and pneumatic This is the input of a pneumoelectric generator, the pneumatic output of which is connected to the input of an inert gas flow controller.

The drawing shows a block diagram of an apparatus for automatically sampling gas from a stream.

The device consists of an analyzer gas sampler 1, an inert gas flow regulator 2, an analyte flow rate regulator 3, an electric pulse generator 4 with adjustable duty cycle, a pneumoelectric generator 5 generating an alternating electric current due to the energy of an inert gas flow through it, electropneumatic a converter 6, a normally-open valve 7, a normally-closed inert gas discharge element 8, a blocking valve 9, and an inert gas supply line 10. The device works as follows.

The inert gas flow regulator 2 stabilizes the flow through the pneumoelectric generator 5 and the electropneumatic transducer 6. The pneumoelectric generator 5, using the energy of the inert gas flowing through it through the supply line 10, generates an electric alternating current that is used to power the electronic circuit of the electric generator 4 pulses with adjustable duty cycle. Electrical impulses are supplied to an electropneumatic transducer 6, which converts them into a corresponding pressure differential between the inlet and the outlet. The normally open valve 7 under the action of this differential, applied to it, closes and cuts off the flow of inert gas to the control input of the separator 1. This increases the pressure at the outlet of the electropneumatic converter 6, which becomes higher than the pressure of the analyzed gas and opens the normally-closed element 8 inert gas discharge to the atmosphere. The flow rate controller 3 of the analyzed mixture continuously draws gas for analysis. At the moment of shutting off the inert gas supply to the control input of the sampler 1, a portion of the analyzed gas is taken. In the absence of an electrical signal on the electropneumatic converter 6, the pressure drop between its input and output drops and the normal-open valve 7 under the action of the spring, opens, the flow of inert gas flows to the control input of the selector 1, and the normally-closed reset element 8 closes the discharge of inert gas into the atmosphere. In this mode, sampling of the gas to be analyzed does not occur, and the sampler is purged with an inert gas. The generator 4 electric pulses produces periodic pulses with a frequency of 0.1-0.05 Hz and a duration of 0.05-0.5 s. In this case, periodic sampling of portions of the gas to be analyzed takes place, which are displaced in selector 1 with portions of inert gas and at the outlet form a mixture of a certain, constant ratio. The block valve 9 ensures that the line of the gas to be analyzed overlaps when the pressure of the inert gas drops below the permissible value.

RIG + 0.2-0.4 kgf / cm2, where RIG is the inert gas pressure at the device inlet;

EGR - pressure of the analyzed gas in the process pipeline.

A decrease in the pressure of the supply nitrogen causes the inert gas consumption to disappear at the control inlet of the sampler 1. In this case, there is a continuous selection of the gas to be analyzed, which causes a quick plug-in of the sampler. When the blocking valve 9 is triggered, the flow rate of the gas to be analyzed is stopped and this prevents the take-off of the sampling device 1.

High reliability of the device is ensured by using membrane elements in the mode of one-sided small pressure drops in the range of 0.05.

0.2 KGS / CM2.

The stability of dilution of the analyzed gas with inert gas is ensured by the stability of the electronic pulse generator 4 and the speed of the electropneumatic transducer 6.

The economic effect on the plant with a capacity of 60000 tons of ethylene per year from one device will be 80 thousand rubles.

Claims (2)

1. USSR author's certificate No. 458731, cl. G 01 N 1/22, 05/18/73. 2. USSR author's certificate No. 453606, cl. G 01 N 1/22, 1/30/3/73 (prototype).