SU426182A1 - DEVICE FOR DETERMINING THE COMPOSITION OF GAS MIXTURES - Google Patents

Description

one

The invention relates to gas mixture analysis devices. The device is intended to automatically determine the composition of a gas mixture by the potential of a breakdown gap and can be used in work with sensors, in which as a result of the formation of ions in the gas phase under the action of an electric field, a jump-like current is observed.

To determine the composition of gas mixtures, gas analyzers are used, whose work is based on measuring the voltage of the breakdown discharge gap when changing the state of the gas in the sensor.

Known gas analyzers have insufficient selectivity.

The purpose of the invention is to expand the measurement range and increase the selectivity of the device for determining the composition of the gas mixture.

This is achieved by sequentially switching between a synchronization unit, the input of which is connected to the output of a clock generator, and a high current generator, the output of which is connected to a measuring ionization sensor.

The drawing shows a block diagram of the proposed device.

The clock pulse generator 1 sets the rate of operation of the device and determines the onset of each measurement cycle. The clock pulse repetition period is selected based on the spectral characteristic of the change in gas concentration over time in accordance with the Kotelnikov theorem. The generator operation is provided either in standby mode when controlled from an external device, for example, a digital control machine, or in self-oscillating mode. A linearly varying high voltage pulse generator 2 operates in standby mode and serves to power the ionization sensor with impulses with predetermined characteristics and control the operation of the secondary recorder. Measuring circuit 3 captures the potential of a discharge gap in an ionization sensor filled with a gas mixture.

A feedback pulse generator 4 is provided to stop the generation of an electrical measuring pulse at the time of the discharge gap. Secondary

The recorder 5 registers the voltage of the breakdown gap, functionally related to the concentration of the gas mixture in the ionization sensor. Synchronization unit 6 launches

heat pulse generator during the passage of an electrical measuring pulse with a shift in relation to the front edge of the measuring pulse. The shift time can be fixed or determined by an automatic search system in a certain time interval, depending on the nature of the analyzed gas. The synchronization unit is subject to strict requirements with respect to the stability of the shear time. For example, fadron-type generators can perform this function.

A strong current pulse generator 7 operates in a standby mode and serves to provide the measuring electrode with a short, high-power electric pulse, through which pulsed heating of the measuring electrode is carried out in order to change the energy state of the surface of the solid - the adsorbed gas is specific to a specific gas system located in contact with the surface of the measuring electrode.

In the device from generator 1, the clock pulses with a period of time T, shifted in time relative to each other, are sent to generators 2 and 7 and the secondary recorder 5. In the secondary recorder, the first pulse is reset with the first pulse, and the second pulse starts the secondary recorder 5, the third synchronizing pulse in time is the high current pulse generator. The generator 7 provides the measuring electrode with a powerful short-time electric pulse that pulses the measuring electrode.

In the case of adsorbed molecules 11, due to a thermal pulse with certain parameters, it provides a selective decrease in the potential of the discharge gap. In the moment of breakdown of the gap in the sensor, there is an abrupt increase in current. A surge current through the generator 4 pulses reverse feedback enters the generator 2 and causes a termination

generation of an electrical measuring pulse in generator 2 at the time of the breakdown of the discharge gap. The generation breakdown pulse arrives at the secondary recorder 5 and records the voltage of the breakdown, which is fuvcioially related to the concentration of the gas mixture in the sensor. The device is in the considered state before the onset of a new measurement cycle.

Subject invention

A device for determining the composition of a gas mixture, comprising a clock pulse generator, a linearly varying high voltage pulse generator, a feedback pulse generator, a measuring circuit, and a secondary recorder, characterized in that, in order to expand

measuring range and improving the selectivity of analysis; a synchronization unit is connected in series, the input of which is connected to the output of a clock generator, and a high current pulse generator, the output of which is connected to a measuring electrode of an ionization sensor.