SU1295337A1 - Flame ionization detector - Google Patents

Abstract

This invention relates to gas chromatography, in particular to detection devices. The purpose of the invention is to simplify the design, increase the detection sensitivity. For this, the ionization chamber of the detector is formed by a cone collector mounted on the base of the chamber located below the upper edge of the burner nozzle, which is the diffuser torus mounted on the base of the burner and enclosing it with a gap. The apex of the conical ionization chamber is connected to the exit channel of the combustion products, which is made in the cylindrical part of the collector electrode and in the insulator of the collector electrode, which exits at one end to the outside of the detector housing. The detector is provided with a spring located inside the housing between the lower part of the insulator of the collector electrode and the ring associated with the upper part of the housing. The collector electrode isolator, isolator: torus diffuser and burner are installed in the housing, 1 sludge. i (L (G SP with & 0 1

Description

The invention relates to gas chromatography, in particular to detectors for gas chromatographs.

The purpose of the invention is to simplify the design and increase the detection sensitivity.

The drawing shows the proposed device, the cut.

The flame ionization detector contains a housing 1, a base 2 with input channels of hydrogen 3, air 4, and a carrier gas from a chromatographic column 5. On the base, a burner 7 with a nozzle 8 and a base 9 are installed through the sealing ring 6 of electrically insulating material in which holes 10 are made for the passage of air. In the center of the case on the insulator 11 a collector electrode 12 is fixed with a conical lower part 13 ,.

On the base of the burner 9, an insulator-diffuser 14 is installed, the upper plane of which is located below the upper edge of the nozzle of the burner 8, forms an ionization chamber 15 with a tapered part 13 of the collector electrode 12. Between the burner and the diffuser there is an air passage 16

In the upper part of the isolator 1I, coming out of the detector with its end 17, channel 18 is made to exit

(Combustion products, which are amplified and recorded as a forehead, channel 19 in the collector electrode is connected to the ionization chamber 15. In the lower part of the insulator I, an ignition coil 20 is fixed, which goes into the radial channel 21 of the collector electrode, which connects combustion products,

On insulator 11, a spring 22J is mounted which, by its second end, rests on a ring 23 connected by means of a locking ring 24 to the upper part of case 1. The case is connected by means of pins 25 and 26 to the base 2 with a bayonet connection. An electrical conductor 27 connected to the burner 7 passes through the hole in the base, and through the insulator 11 and conductor 28, connected to the collector electrode 12, the Insulator-diffuser 14

a collector electrode 12 with an insulator I 55 of the Zion chamber with an output channel of the pro and burner 7 is installed in a housing with combustion ducts, which are made in the cylindrical part of the collector electrode and in the insulator of the collector electrode.

the possibility of providing by means of the spring 22 a hermetic sealing of the burner 7 with the base 2, -isol; the possibility of carrying out the ion-diffuser with the base of the burner 9 and the collector electrode with the diffuser-insulator,

Plasma Ionization Detector

It works on the well-known principle of ionization of molecules of organic substances in a flame of hydrogen. Hydrogen through channel 3 enters the burner 7, air to maintain combustion through the channel

4 at the base, the holes 10 in the burner and the gap 16 enters the space around the burner nozzle. The flame is ignited by the lighter 20, which is energized

ignition. The output of the combustion products is depleted through the hole 21 of the collector electrode and the channel 18 of the insulator 11. A constant polarizing voltage of 150-300 V is applied between the burner nozzle 8 and the collector electrode 12 and an electric field is generated. The carrier gas from the chromatographic column through the channel 5 and the burner nozzle enters the

Combustion zone. An ionized medium is formed in the hydrogen flame between the burner nozzle and the collector electrode. Ions under the action of an electric field formed between

electrodes, move between electrodes and are neutralized on them (give off i), thereby creating a current in the external circuit of the detector which

35 new current. Organic matter

entering the detector from the chromatographic column, when burned in a hydrogen flame, causes a noticeable increase in the ionization current. Ionic

40 current (signal). The detector is directly proportional to the amount of organic matter entering the flame per unit of time.

j Performing the ionization chamber of the detector in the form of a sealed truncated cone enclosing the burner nozzle, b. and the connection of the apex of the cone ionizes the ability to carry out ionization in a small limited volume, which simplifies the design of the detector and reduces its size, since the design is much simpler. orpus detector performing in the proposed. the detector only has a shield function, and the case is reduced in size, since the volume of the ionization chamber is reduced. Since the ionization and yield of combustion products are carried out only in the volume of the collector electrode and its insulator and combustion products do not affect the housing, it can be made of non-corrosion-resistant materials, for example, from thin-walled carbon steel pipes, which also simplifies the design of the detector . Placing the ignition coil in the radial channel of the collector electrode, which is connected to the exit channel of the combustion products, simplifies the design and reduces the dimensions of the detector, since it eliminates the need to install an additional electrical insulator.

The detector is supplied with a spring located inside the case between the isolator of the collector electrode and the ring connected to the upper part of the case, and the installation of the electrode isolator to the oldetor of the oltortor and the torch and the torch in the case to the connection of the case with the bayonet base connection with the possibility of providing by means of a spring a hermetic seal of the burner with the base of the detector, of the isolator-diffuser with the base of the burner, and of an elec- trode electrode with an insulated cone with a side surface formed by a conical electrode - a collector, the lower edge of which is located below the upper cut-off 5 J of the burner nozzle, improves the detector sensitivity in comparison with the known commercially available detectors, since it provides the optimum direction of gas flows, better forces for burning a flame and a more uniform distribution of the electric field in the ionization zone .

The test results of the sample are the following; 5; the followings are: the detector works stably for a long period. The background current of the detector is IjS lO A, and the sensitivity threshold is 1-10 mg / ml for propane, which is 2 times better than that of the detectors of commercially available color chromatographs.

20

Claims (1)

Invention Formula 25 thirty A flame ionization detector comprising a housing, a base with gas inlet channels, a burner with a base and a nozzle, which is a feed electrode, a conical collector electrode with an insulator, and a combustion product exit channel, characterized in that, in order to simplify the design and increase sensitivity . Detection, an insulating sleeve-diffuser is installed between the base of the rocket and the lower part of the collector electrode; the insulating sleeve is a diffuser; the burner nozzle is closed with a gap and the closed nozzle is formed with the collector electrode. torus-diffuser simplifies design - KOHycHjro ionization chamber with narrowing the burners and bases, since the fasteners for the burner are eliminated, the dimensions of the detector are reduced, since the tightness of the ionization chamber and the strictly directed flow of gases provide an opportunity to reduce the volume of the ionization chamber, and improve ease of use, as for disassembling and assembling the detector only a slight twist of the de-: tector in the bayonet connection, ; In addition, the implementation of ionization: the chamber in the form of a sealed all-55 upper part of the housing. cone with a lateral surface formed by a conical collector electrode, the lower edge of which is located below the upper edge of the burner nozzle, increases the sensitivity of the detector compared with the well-known commercially available detectors, as it provides the optimum direction of gas flow 0  better forces for burning the flame and a more uniform distribution of the electric field in the ionization zone. The test results of the sample are the following; 5; the followings are: the detector works stably for a long period. The background current of the detector is IjS lO A, and the threshold of sensitivity is 1-10 mg / ml. propane, which is 2 times better than with detectors of serially injected chromatographs Color. 20 Invention Formula 0 25 thirty A flame ionization detector comprising a housing, a base with gas inlet channels, a burner with a base and a nozzle, which is a feed electrode, a conical collector electrode with an insulator, and a combustion product exit channel, characterized in that, in order to simplify the design and increase sensitivity . Detection, an insulating sleeve-diffuser is installed between the base of the rocket and the lower part of the collector electrode; the insulating sleeve is a diffuser; the burner nozzle is closed with a gap and the closed nozzle is formed with the collector electrode. upstream of the gas flow, the base of which is the upper plane of the diffuser sleeve, located below the upper edge of the burner nozzle, and the top of the conical ionization chamber is connected to the combustion product exit channel, which is filled in the cylindrical part of the collector electrode and in the insulator of the collector electrode of the torus, with one end extending outside the detector housing, the detector being equipped with a spring mounted on the collector electrode isolator between its upper plane .. Sdros Hydrogen Editor Oh, Bugir Compiled by And, Shiganov Tehred A. Kravchuk. Proofreader. Shekmar Order 613/52 Circulation 777 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4