SU1758709A1 - Gaseous-discharge electrodeless high-frequency lamp - Google Patents

Abstract

Usage: lamps emitting spectra of chemical elements are intended for use in spectral techniques, in atomic absorption equipment, in goniometers-spectrophotometers. Summary of the invention: the lamp has a sealed flask filled with hydrogen. Inside the bulb is a hollow insert with a hole. Dielectric elements, such as glass granules, are distributed throughout the entire gap between the liner and the wall of the bulb (with the exception of the radiation exit zone). When applied to an external RF circuit, the voltage from the RF generator in the cavity of the liner ignites the RF discharge in hydrogen, and the spectral lines of hydrogen are emitted. 1 h. item f-ly, 1 ill.

Description

The invention relates to electrical engineering, namely, gas discharge lamps without electrodes inside a cylinder, emitting spectra of chemical elements and intended for use in spectral techniques in atomic absorption equipment, goniometers, spectrometers, etc.

A lamp is known that comprises a hermetic cylindrical flask of optically transparent material filled with a working gas, in which a cylindrical hollow insert of an optically transparent material is installed, provided with an axial orifice.

However, if hydrogen is used as a filler, the durability of the lamp is low (15-25 hours).

This is associated with a decrease in the amount of hydrogen due to its diffusion through the walls of the flask to the outside. As a result, the emission intensity of the spectral lines is reduced.

hydrogen, and then the lamp goes out without the possibility of re-ignition.

The closest to the technical essence of the invention is a gas-discharge electrodeless RF lamp containing an optically transparent material made of an optically transparent material cylindrical flask filled with hydrogen, and a cylindrical hollow insert with an axial orifice mounted inside it with a gap, and the size of this gap is O , 01-0.08 of the inner diameter of the bulb, and the outer surface of the liner is separated from the inner surface of the flask by dielectric elements, the total contact surface of which is with the inner surface of the bulb does not exceed 0.006 of its surface. The dielectric elements are protrusions above the surface of the liner. As shown by testing, the durability of such

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hydrogen lamps increased to 100-120 hours.

The disadvantages of the famous lamp are as follows.

Since the working volume differs little from the total internal volume of the lamp (due to the small size of the gap between the insert and the bulb, an increase in which exceeds the specified value leads to an RF discharge, in the volume of the gap, and the service life is not increased) the supply of hydrogen, which provides a further increase in service life, is possible only by increasing the total volume of the lamp. However, the dimensions of the lamp increase (in particular, unification with manufactured electrodeless lamps in size) is not achieved, the size of the light of the body is useless, the RF power required for the lamp to increase significantly, i.e., the efficiency of the lamp decreases. In addition, the radiation stability is deteriorated due to plasma fluctuations that do not completely occupy the flask volume. With a decrease in order to unify the dimensions with serial lamps of the lamp dimensions, its durability falls due to the small supply of hydrogen. In addition to this, the lamp is known to be non-technological, i.e., the liner and bulb must be carefully adjusted, otherwise either the liner does not fit into the flask, or the gap exceeds the allowable and the RF discharge occurs outside the liner volume, and the service life decreases sharply, t. e. the reliability of the lamp is insufficient.

The purpose of the invention is to reduce power consumption and size while increasing reliability,

 The goal is achieved by those. that in a gas-discharge electrodeless high-frequency lamp containing a hermetic flask made of optically transparent material filled with hydrogen and a hollow insert with a hole installed inside it with a gap in which the dielectric elements are located. The dielectric elements are distributed over the entire volume of the gap except for the radiation exit zone.

As dielectric elements glass 1 or quartz chips may be used. The gap volume can also be filled with fiberglass or quartz fiber.

It has been experimentally found that such an implementation of the lamp ensures the achievement of a positive effect, which is the aim of the invention. The volume of the cavity of the insert where the high-frequency discharge in hydrogen burns can

be reduced to 1-2 cm with the total lamp volume, an order of magnitude larger, i.e., the relative supply of hydrogen increases accordingly, which creates prerequisites for increased service life, but the occurrence of discharge outside the cavity of the liner is excluded due to severely hampered conditions for the occurrence and burning of the high-frequency discharge in the microcavities between the dielectric elements. Accordingly, the reliability of the lamp is increased, and the RF power consumption is reduced, while the lamp dimensions can be the same as those of the spectral LV2 electrodeless lamps, and its operation can be ensured by the RF generator built into the lamp design.

The absence of the need to adjust the dimensions, since the gap size ceases to be critical and can have a considerable scatter, significantly improves manufacturability, and lamps in the conditions of mass production.

A small discharge volume of the lamp is completely occupied by the RF plasma, which eliminates the conditions of instability of its radiation, and the reduction in the size of the light of a healthy body increases the efficiency of the lamp.

Increased durability can be explained as follows.

It is known that the service life of electrodeless hydrogen lamps is reduced both due to the high penetrating power of hydrogen and its leakage through the walls of the flask warmed by the lamp, and due to the hydrogenation of glass containing bound oxygen. Under RF-free lamp-free conditions, when the discharge plasma is in direct contact with the hot walls of the flask, the atomic hydrogen produced during the dissociation of hydrogen molecules into the discharge, having the smallest atomic radius among all chemical elements, easily penetrates into the wall material and rapidly diffuses before going outside. Therefore, the density of hydrogen in the volume of the flask decreases rapidly with all the negative consequences. In the proposed construction, hydrogen atoms, having passed through the wall of the liner and being in the gap between it and the flask, recombine into molecules, i.e., only molecular hydrogen is present at the flask wall, whose penetration is an order of magnitude smaller than atomic, and the temperature of the walls of the bulb is much lower than the temperature of the walls of the liner, due to the distance from the RF discharge zone. Therefore, the outflow of hydrogen to the outside compared to the analogs is sharply slowed down, the molecular hydrogen is returned to the discharge volume through the bore of the liner. As for the hydrogenation of glass, its role in such a construction is secondary, according to studies conducted in the emission spectrum of the prototype lamp of the oxygen line is weakly expressed. In the proposed lamp, it is possible to place a water-absorbing element that is outside the discharge volume, but associated with a filler gas (this element can act as one of the dielectric elements).

The drawing shows a variant of the proposed lamp.

The discharge of the electrodeless RF lamp contains a transparent flask 1 filled with hydrogen, in which the insert 2 is installed with a gap 2. having an opening 3. In contrast to the prototype, the shape of both flask 1 and insert 2 is not critical, i.e. to the size of the gap between their walls. In this embodiment, the liner 2 is cylindrical, but may be spherical. The process 4, which plays only a fixing role, is used to fix the insert 2 in flask 1, but another known solution can be used. The dielectric elements 5 fill the entire space between the liner 2 and the bulb 1, except for zone 6, through which the lamp radiation is output, here the gap is reduced so that the dielectric elements 5 cannot penetrate it, as a result the outgoing radiation flux does not weaken due to for dissipation. The output side of the flask 1 can also be output; in this case, the gap between the insert 2 and flask 1 decreases, respectively, at the side wall. In contrast to the prototype, the location is at the side wall. Unlike the prototype, the opening of the hole 3 is not critical, it may not be axial, because due to the distance of the liner from flask 1, the possibility of atomic hydrogen reaching the walls of flask 1 before its recombination is practically absent. The possibility of atomic hydrogen penetration to the walls of flask 1 through the thickness of several dielectric elements 5 through their contact zones is also minimized, since there is a much greater probability that hydrogen atoms will come back into the volume of the lamp during such movement and recombine into molecules. Therefore, it is advantageous to increase the size of the gap between the insert 2 and the flask 1, but at the same time the discharge zone is distant from the external RF inductor, therefore, the specific size of the gap is chosen taking into account the design of the excitation unit

working frequency, etc. In concrete samples, the flask 1 is made of quartz glass, its outer diameter is 16 mm, the wall thickness is 1 mm, the liner 2 is also made of quartz glass, its outer diameter is 10 mm, and the wall thickness is not more than 1 mm.

The implementation of these parts of glass C-52-1, as in the case of the prototype, makes it possible to virtually eliminate the signs

0 hydrogenation of glass, but the manufacturability of such a lamp is lower due to the need for thorough annealing and possible cracking of the glass. The diameter of the hole 3 may be small. 0.5–1 mm, which excludes the possibility of the penetration of dielectric elements 5 into the volume of the insert 2, but does not reflect on the normal operation of the lamp due to the high fluidity of hydrogen. The lamp is filled with hydrogen under

0 with a pressure of 70–80 Pa, when the lamp is operated due to the resulting temperature difference, the density of hydrogen in the volume of the insert 2 somewhat decreases and is optimal for the burning of the RF discharge and from 5 emission of atomic hydrogen lines. The material of the dielectric elements 5 may be different; it should provide low losses in the RF field and hardly interact with hydrogen. In specific

0 samples, elements 5 are particles of quartz glass with transverse dimensions within 0.2-0.5 of the gap between insert 2 and flask 1, except for the gap in the output region, where the gap is smaller than the dimensions of elements 5. To increase the volume of hydrogen, the elements 5 it is advisable to perform in the form of spherical granules, however, and with their other form, the supply of hydrogen compared to

0 prototype significantly increased. The hydrogen supply increases even more if quartz or fiberglass is used as the dielectric elements, but in this case lamp outgassing

5 is complicated when pumped out. Making several granules of silica gel or other water-absorbing material completely eliminates the effect of hydrogenation and improves lamp performance.

0 The device operates as follows.

When applied to an external RF circuit, the voltage from the RF generator in the cavity of the liner 2 is ignited by RF discharge in hydrogen,

5, the spectral lines of hydrogen are emitted, primarily with a length of 434.0. 486.1 and 656.2 nm. Since hydrogen is contained in the molecular form in the gap, including in the zone of the lamp radiation exit, when self-radiation lines pass through the gap of the atomic radiation.

The proposed electrodeless hydrogen lamp is more reliable in comparison with the known one and consumes less RF power, while its dimensions are smaller, other elements are unified with serial lamps. This enhances the performance of the apparatus where the lamp is used. Improving its manufacturability facilitates its production under serial conditions.

Claims (2)

Claim 1. Gaseous electrodeless high-frequency lamp comprising five hermetically sealed flask filled with optically transparent material, filled with hydrogen and a hollow liner with a hole installed inside it with a gap in which dielectric elements are located, characterized in that, in order to reduce its consumed power and size while improving reliability, these dielectric elements are distributed throughout the gap, with the exception of the radiation output zone. 2. The lamp according to claim 1, characterized in that granules of glass are used as dielectric elements.