RU2575516C2 - Multinozzle oxydric torch - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to flame processing of materials. This oxydric torch comprises case with nozzle plate. Plate nozzles are composed of metallic capillary 0.1-0.6 mm ID tubes sealed in through bore of metallic or ceramic nozzle plate. Extra plate is arranged in torch case parallel with nozzle plate. Said metallic capillary tubes are sealed in through bores of nozzle and extra plates for water to flow there between. Nozzle plate has one or several ledges extending through appropriate grooves in extra plate. Capillary tubes-nozzles are sealed in through holes in said ledges. Gaps between ledges and extra plate are sealed.

EFFECT: fire- and explosion-proof design, lower production costs.

3 cl, 8 dwg

Description

The invention relates to burners for flame treatment of materials, and more particularly to multi-nozzle hydrogen-oxygen burners used in the production of quartz optical fibers and single crystals.

The technology of the above industries is associated with the need to heat surface areas by burning a hydrogen-oxygen mixture exiting the burner nozzles at a speed of not more than 30-60 m / s. For this purpose, external-oxygen hydrogen-oxygen burners are used everywhere, despite their inferior thermal performance compared to pre-mixed burners, as well as the explosion and fire hazard of cylinders with compressed (or tanks with liquefied) gases, which are necessary for their supply. It is impossible to use explosion-proof electrolysis water generators to power external mixing burners, as generators produce a mixture of hydrogen with oxygen, and not each of these gases separately. It is also not possible to replace the external mixing burners with industrial oxygen-gas pre-mixing burners, as at the required low speeds of the hydrogen-oxygen mixture, the so-called “back strike” occurs - the front of the flame is drawn into the burner.

The subject of the present invention is a hydrogen-oxygen pre-mixing burner that operates stably when the gas mixture leaves the burner nozzles at speeds of up to 30-60 m / s.

It was experimentally established that for burning a hydrogen-oxygen mixture with such low speeds, the nozzle diameter should be no more than 0.55-0.30 mm, its length should be at least 5 mm, and there should be no transverse irregularities on the walls that swirl the gas flow. Industrial gas-oxygen burners have nozzles with a diameter of 0.60 mm and more [1, 2]. Therefore, they cannot operate at the required feed rates of the hydrogen-oxygen mixture.

Closest to the proposed, adopted as a prototype, is the burner of the company "TETRA LAVAL HOLDINGS AND FINANCE S.A." [3]. The nozzle plate of this burner is a stack of flat metal sheets with a thickness of 0.5-2.0 mm, in which precisely positioned through holes are made. The sheets are stacked so that at least part of the holes are aligned with each other, forming nozzles. This design allows you to make holes of a sufficiently small diameter (for example, a laser) and to form long nozzles. However, it is not possible to obtain nozzles with smooth walls. The gas flow will necessarily swirl at the borders of the sheets. In addition, a decrease in the diameter of the nozzles of the burner leads to a significant reduction in the flame core. Because of this, the nozzle plate needs to be brought close to the heated surface, and it will be heated very strongly by both the gas flow reflected from the heated surface and its radiation. Therefore, for the long continuous operation necessary both in the manufacture of quartz optical fiber and in the growth of single crystals, the nozzle plate must be intensively cooled. However, this design of the burner does not allow liquid (water) cooling of the nozzle plate.

In the proposed burner nozzles are metal capillary tubes, hermetically fixed in the through holes of a metal or ceramic nozzle plate, flush with its outer surface. The industry produces metal capillary tubes with an inner diameter of 0.10-0.12 mm or more with different wall thicknesses (see GOST 14162-79 and others). Therefore, it is always possible to choose a tube with the required inner diameter and with such an outer diameter (0.6 mm or more) that the holes for the capillaries in the nozzle plate are feasible. The described burner is shown in FIG. 1. The capillary tubes 1 are fixed in the nozzle plate 2 mounted in the housing 3, into the cavity "A" of which a gas mixture is supplied. In this case, the nozzle plate may be rectangular, round or any other shape in accordance with the desired shape of the heating spot. Furthermore, it may not be flat, as in FIG. 1, but arbitrarily bent, for example, as in FIG. 2.

In contrast to the prototype, the proposed design made it possible to obtain long nozzles of small diameter with smooth walls.

Embodiments of a burner with a water-cooled nozzle plate are shown in FIG. 3 and FIG. 4. In both cases, the tubes 1, which are nozzles, are sealed tightly in the through holes of the nozzle 2 and the additional 4 plates installed in the housing 3 parallel to each other (the options differ by fixing the tubes in the additional plate 4). Gas is supplied to cavity “A”, water is supplied to cavity “B”. Instead of water, you can use other coolants. Such a burner, unlike the prototype, does not overheat and therefore can continuously work for an unlimited time.

The construction shown in FIG. 3 and FIG. 4, technological only in mass production. In the case of piece and small-scale production of such burners, it is difficult to ensure both the alignment of the holes in the nozzle and additional plates, and the reliable sealing of the numerous gaps between the capillary tubes and the walls of the holes in both plates. The burner shown in FIG. 5, more technological. On its nozzle plate 2, ridges-protrusions are made, which pass through the grooves in the additional plate 4 into the cavity “A” of the burner. Rows of holes for capillary tubes 1 are drilled in the ridges-protrusions. Therefore, to ensure gas tightness, it is sufficient to seal the gaps between the capillary tubes 1 and through holes in the ridges, and for sealing along the cooling water, to seal the gaps between the ridges-ridges and grooves in septum 4.

The number of ridges-protrusions on the nozzle plate can be different and in each of them there can be several rows of holes, and not one. Examples are in FIG. 6 and FIG. 7. In FIG. 6 shows a burner with five ridges-protrusions on the nozzle plate 1 and one row of holes in each of them (capillary tubes not shown). In this case, the additional plate 2 is also part of the burner body forming the water cooling cavity. The holes in the ridges are stepped in order to facilitate drilling. Instead of a series of holes of larger diameter, one continuous slot can be made in the crest-protrusion. In FIG. 7a shows a burner with one ridge-protrusion and seven rows of holes in it, and in FIG. 7b is a burner with four ridges-protrusions, in two of which one row of holes, and in the other two, three rows (capillary tubes in Fig. 7 are not shown, as in Fig. 6). The diameters of the capillary tubes in the ridges, protrusions of the nozzle plate can be the same or different.

The proposed burner replaces the hydrogen-oxygen burners of external mixing used in the production of optical quartz fiber and in the growth of single crystals. Such a replacement

- makes the specified production explosion and fire safe, as allows the use of explosion-proof electrolysis-water generators instead of compressed cylinders or tanks with liquefied hydrogen and oxygen, which are currently used everywhere;

- removes restrictions on the location of such industries, due to fire hazard;

- reduces production costs, because Electricity consumed by electrolysis-water generators costs 5-10 times cheaper than refueling the corresponding number of cylinders.

The operating experience of such burners in the manufacture of quartz optical fibers with special properties has proven their effectiveness and reliability during continuous operation.

Literature

[1] Gas-flame soldering of metals. - All-Union Research Institute of Autogenous Metal Processing. Guidance materials. Issue 7. Moscow, MASHGIZ, 1955

[2] Nechaev V.D. Burners with external and internal nozzle mixing. - In the book. Proceedings of the All-Union Research Institute of Autogenous Metal Processing. Issue 7. Automatic gas welding, oxygen and gas-electric cutting. Moscow, Engineering, 1964 71-91.

[3] RU 2483247 C2, F23D 14/56 F23D 14/10, 01/20/2009.

Claims (3)

1. A multi-nozzle hydrogen-oxygen burner comprising a housing with a nozzle plate, characterized in that its nozzles are metal capillary tubes with an inner diameter of 0.1 to 0.6 mm, sealed tightly in through holes of a metal or ceramic nozzle plate. 2. The multi-nozzle hydrogen-oxygen burner according to claim 1, characterized in that an additional plate is installed in the burner body parallel to the nozzle plate, metal capillary tubes are sealed in through holes of the nozzle and additional plates, between which water flows. 3. The multi-nozzle hydrogen-oxygen burner according to claim 2, characterized in that on the nozzle plate there are one or more ridges-protrusions passing through the corresponding grooves in the additional plate, the capillary tube nozzles are hermetically fixed in through holes made in the ridges protrusions, and the gaps between the ridges-protrusions and the additional plate are sealed.

Images