RU56998U1 - GAS FLOW CONTROL DEVICE - Google Patents

Abstract

The gas flow control device is designed to control the gas flow and can be used in the development of devices for the analysis of gas composition. The device consists of a main channel for the passage of gas, in which two constant chokes are arranged in series, one on the gas inlet side and the other on the gas outlet side to the gas analyzer sensor. The section of the main channel between the first and second chokes is connected by an additional channel to the gas pressure regulator in the line "to itself". The same line is a bypass line. Instead of a second constant choke, a group of constant chokes connected in parallel can be installed to power several sensors. The device is designed to work with clean gases and protects clean gases from contamination by impurities.

Description

The proposed utility model of the device relates to the field of gas analysis and can be used in the development of instruments for analyzing the composition of gas.

Known devices for regulating the flow of gas, including a pressure regulator in the line "after itself" and a constant or variable throttle. Using the pressure regulator, a specific pressure is set in front of the throttle. With a constant cross-section of the orifice of the throttle, the flow rate will remain constant when the pressure at the inlet to the device changes.

A disadvantage of the known devices is that they are not very suitable for controlling the flow of pure gases.

Pure gases include gases in which the content of impurities is severely limited. The content of impurities should not exceed parts per million by volume, i.e. in a million pure gas molecules, the number of impurity molecules should be no more than a few units, sometimes tens of units.

Non-metallic materials, especially rubber, from which sealing gaskets and membranes are made, are one of the sources of foreign impurities in gas devices.

Through molecular diffusion, impurities penetrate from the surrounding atmosphere (these are oxygen, nitrogen, carbon dioxide). Non-metallic materials themselves, from their mass, also emit impurities that clean the gas through diffusion.

For these two reasons, impurities can amount to several tens of parts per million.

In the known device for regulating gas flow, non-metallic materials to a greater extent contain a gas pressure regulator in the line "after itself" and to some extent a variable orifice, if applicable.

The best element for building a gas flow control device is a permanent choke. It can be made without a single non-metallic part. A permanent choke is a hole with a certain diameter, made with high accuracy in a metal or, for example, in synthetic ruby or sapphire.

Based on the foregoing, it is proposed the following device for regulating the flow of gas, shown in figure 1.

The device comprises a main channel 1, in which permanent chokes 2 and 3 are located. A section 4 of the main channel between the chokes 2 and 3 is connected by an additional channel 5 to the gas pressure regulator in the line "to itself" 6.

Gas under a certain pressure enters the constant throttle 2 and after passing section 4 it enters the constant throttle 3. In section 4, with the help of the pressure regulator in the line "to yourself" constant pressure is maintained. With constant pressure in section 4 and a constant cross-section of the throttle 3, the gas flow rate at the outlet will be constant.

The operation of the gas pressure regulator in the line "to oneself" is based on balancing the elastic force of the spring 7 acting on the membrane 8 and the gas pressure force under the membrane in the cavity 9. The valve 10, located in the center of the membrane 8, regulates the outflow of gas from the chamber 9, due to wherein the pressure in the chamber 9, the additional channel 5 and section 4 is maintained constant. The level of this pressure is set using the screw 11, acting through the disk 12 on the spring 7.

In the future, the gas outlet flow rate will remain constant and independent of the change in pressure at the gas inlet.

The gas flow through the additional channel 5 at the same time serves as a bypass stream, reducing transport delays when using the device in gas analyzers.

Thus, the gas flow going through the main channel 1 to the sensor of the gas analyzer does not have contact with non-metallic materials and is not contaminated with impurities.

The gas analyzer can have several sensors, for example, on microconcentrations of oxygen, carbon dioxide, nitrogen. In this case, additional constant chokes 3.1,3.2 are installed parallel to the constant choke 3, one for each sensor (see figure 2).

In January 2006, a prototype gas flow control device was manufactured and tested with a positive result. In February-March 2006, the device was introduced into the Baikal-5Ts hygrometer and the Svet gas analyzer, in which one sensor is each, and the Onyx gas analyzer, in which there are three sensors.

Claims (1)

A gas flow control device comprising a main channel for gas passage and a constant choke, characterized in that a second constant choke or a group of constant chokes connected in parallel is installed in series with the first constant choke, and the channel section is between the first and second constant chokes, or between the first a constant choke and a group of chokes connected in parallel is connected by an additional channel to the gas pressure regulator in the line "to yourself".