JPH0445305A - Sleeve for fuel injection nozzle - Google Patents

Abstract

PURPOSE:To improve abrasion resistance and crack resistance by providing a cylinder of thin metal plate outside a cylinder of abrasion-resisting nonmetallic material such as ceramics, filling brazing filler metal into a gap between both the cylinders and heating and melting said metal to fill said gap. CONSTITUTION:A sleeve 20 comprises a cylinder 3 of abrasion-proof nonmetallic material such as ceramics having a layer of brazing filler metal 8 over its outer surface and a cylinder 4 of thin metal which is fitted onto said layer. The sleeve 20 is heated in a furnace to melt the metal 8, so that the gap between the cylinders 3 and 4 is filled with the molten metal and further a through hole 11 communicating with a through hole 10a of a body 5 of fuel injection nozzle is provided. Although the sleeve 20 is fitted into a mixing chamber 5' of two-liquid-mixing type formed in the body 5, where mixed flow of two liquids causes violent abrasion, by the use of the cylinder 3 of abrasion-resisting material, the abrasion can be reduced. Furthermore, since the cylinder 3 is compressed by large thermal contraction forces of the cylinder 4 through the metal 8, compressive stresses remain in the cylinder 3, thereby preventing cracks from occurring therein.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a coal-oil mixture (hereinafter referred to as eOM)-fired,
The present invention also relates to sleep for a two-fluid mixture type fuel injection nozzle that is subject to large wear and is applied to coal-water mixture (hereinafter referred to as CWM)-fired boilers.

[Conventional technology]

The injection nozzles used in COM-fired and CWM-fired boilers are usually of the two-fluid mixing type with steam, etc.
Generally, wear resistance and cracking resistance against thermal shock are required. In other words, this injection nozzle has the ability to withstand wear on the passage walls caused by coal particles colliding and passing through at high speed, heating due to radiant heat from the furnace, cooling due to start and stop, and being subjected to thermal shock. It is necessary to prevent cracking.

FIG. 5 shows a part of a sectional view of a fuel injection nozzle of a conventional two-fluid mixing boiler. In the figure, 1a is the injection hole of the nozzle, for example, one is steam and the other is COM or CW.
Two fluids 4a and 5g of M are mixed in the same nozzle la and are ejected to the furnace of the boiler. Reference numeral 2a denotes a sleeve made of a wear-resistant non-metallic material that is attached to the inner wall of the injection hole (mixing chamber) of the injection nozzle body 3a.

[Problem to be solved by the invention]

The sleep 2aK of the conventional non-metallic materials mentioned above is generally %
Ceramics such as 5iCe8'5PJa and cemented carbide such as WC are used.

However, due to material properties, materials with high hardness that have good wear resistance generally have poor toughness and poor cracking resistance due to thermal shock caused by heating and cooling when the boiler starts and stops; It has the advantage and disadvantage that it has poor wear resistance.

For example, SiC has extremely good wear resistance, but cracks occur due to thermal shock caused by starting and stopping during boiler operation, resulting in problems. On the other hand, Si, N4, WC, and the like have extremely good cracking resistance, but their wear resistance deteriorates, resulting in a short life.

It was extremely difficult to develop materials to solve both of the above problems, and it was considered technically difficult to create a ``sleep'' that was hard and hard to break.

In view of this situation, the present invention is an attempt to provide a sleep pipe for a fuel injection nozzle that has excellent wear resistance and good crack resistance.

[Means for Solving the Problems] The present invention provides a cylinder body made of a wear-resistant non-metallic material such as ceramics in a sleeve for a fuel injection nozzle that is inserted and fixed into the mixing chamber wall of a two-fluid mixing type fuel injection nozzle. A cylinder made of a thin metal material is disposed on the outside of the sleeve, a brazing material is installed in the gap between the two, and this is heated and melted to fit over the gap between the two sleeves.

[Effect]

Generally, it is well known that if compressive stress remains in an object, that object is less likely to break.

In the present invention, as a means for applying the compressive stress, a thin-walled cylinder made of a metal material with high toughness is arranged on the outside of a cylinder made of a non-metallic material such as ceramics, which has high wear resistance but is easily broken. A brazing material is placed in the gap and heated and melted to fill the gap between the two cylinders.

That is, in the present invention, the brazing material installed between both cylinders is melted by heating to a predetermined temperature, fills the gap between both cylinders, and eliminates the gap caused by the difference in thermal expansion between the two cylinders. The increase in nine gaps is filled.

After that, the brazing filler metal solidifies during the cooling process, and the diameter of both cylinders shrinks as the temperature decreases, but the metal material with the larger contraction amount on the outside corresponds to the difference in the amount of contraction between the two cylinders. The cylindrical body is plated with gold wire to the inner non-metallic cylindrical body through the molten and solidified brazing filler metal, producing the same effect as so-called shrink fitting, and applying compressive residual stress to the inner cylindrical body. -It will happen.

In this manner, the present invention provides a cylinder for a fuel injection nozzle that is hard to break and has a wear-resistant cylinder on the inside where two fluids pass and is prone to wear.

Ninth, by disposing the brazing material between the two cylinders, the fit between the two cylinders can be made tighter. Furthermore, the soft brazing material acts as a so-called cushion (buffering material) to prevent localized high compressive stress from occurring, eliminating the risk of cracking.

On the other hand, it is also possible to arrange a metal cylinder outside of a wear-resistant non-metallic cylinder and shrink-fit both cylinders, but in this method: (1) Dimensions of both cylinders Accuracy must be extremely high.

(2) In order to secure the shrink-fitting allowance, it is necessary to carry out the shrink-fitting work at a considerably high temperature.

There are constraints on accuracy and productivity, such as (3)
It is extremely difficult to apply compressive stress uniformly, and if a high compressive force is applied locally, there is a risk that the sleeve will crack.

However, in the present invention, as described above, by attaching the brazing material to the gap between the two cylinders and heating and melting it to fill the gap +1 between the two cylinders, The problems associated with the above-mentioned shrink fitting can also be solved.

〔Example〕

An embodiment of the present invention will be explained with reference to FIGS. 1 to 4.

FIG. 1 shows an example of how the sleeper according to this embodiment is attached to a fuel injection nozzle, and corresponds to Figure 5, which shows the sleeper of a conventional fuel injection burner nozzle.

A nozzle hole 1 is provided in the wall of the mixing chamber 5a of the two-liquid mixing wrinkle formed in the fuel injection nozzle body 5, and a sleeve 2 made of cemented carbide (WC) or 5jsN4 with emphasis on crack resistance is provided. A sleeve 20 is attached to the vicinity of the nozzle hole 1 with a ring-shaped spring 9, and is made by joining a cylindrical body 3 made of a non-metallic material such as ceramics and a cylindrical body 4 made of a metal material via a brazing material 8 according to the present embodiment described below. is installed at the junction of the two liquids 6 and 7 inside the mixing chamber 5a where the wear is most severe. One of the two liquids 6 passes through a through hole 10a provided in the fuel injection nozzle body 5.
and the sleep 2 through the nine holes 11 provided in the sleep 20.
The other liquid 7 is supplied into the sleeve 20 from one end of the sleeve 20 through a through hole 10bi provided in the fuel injection nozzle body 5. As the two liquids 6.7, for example, COM and steam are used in the case of COM firing, and CWM and steam are used in the case of CWM firing. Note that the previous sleeper 2 may be omitted and only the sleeper 20 according to this embodiment may be attached.

As shown in FIGS. 2 and 3, the sleeve 20 according to the present embodiment has a brazing material 8 attached to the outer circumferential surface of a cylindrical body 3 made of a non-metallic material such as wear-resistant ceramics, and the sleeve 20 shown in FIG. As shown in FIG. 2, a thin metal cylindrical body 4f is fitted on the outside thereof to form the state shown in FIG. and the cylindrical body 4, and the through hole 10a of the main body 5 of the fuel injection nozzle is filled in the summer.
It is constructed by providing a through hole 11 that communicates with the.

The brazing material 8 used in this embodiment varies depending on the conditions of use, but in general, a soft material such as silver solder is suitable, and its thickness is suitably about 0.05 to 0.02 mm. Furthermore, the gap between the two cylindrical bodies 3.4 needs to be larger than the thickness of the brazing filler metal 8 to be installed, but if the gap is too large, the filler filler metal 8 will not be able to fill that gap. Appropriately, the thickness of the material 8 is +0.05 to 0.1.

As described above, this embodiment configured as above has the following features:
For example, as shown in FIG. 1, it is installed at the confluence of the two liquids that undergoes the most wear in the two-liquid warming type mixing chamber 5a formed in the fuel injection nozzle body 5, but is highly wear-resistant. By using the cylindrical body 3 made of a non-metallic material, its wear can be reduced.

Moreover, as shown by the arrow in FIG. 4, the sleep according to the embodiment fully valves the brazing material 8 due to the large heat shrinkage force of the outer metal cylinder 4 and presses it into the non-metal cylinder 3. A tightening force is applied, and compressive stress remains in the cylindrical body 3, causing the cylindrical body 3, which was originally prone to cracking, to crack.

In addition, by disposing the brazing material 8 between the two cylindrical bodies 3 and 40, the accuracy of the fitting of the two cylindrical bodies 3 and 4 can be reduced, and this brazing material 8 acts as a cutter, It is possible to prevent the occurrence of locally high compressive stress and completely eliminate the risk of cracking.

Table IK shows an example comparing the thermal shock resistance temperature (maximum heating temperature until cracks occur in the sleeve) of this example (SiC is used as the material of the non-metallic cylindrical body) and the conventional sleeve.

According to this, it is shown that the thermal shock resistance temperature of this example is 250° C. higher than that of the conventional SLEEP, and that cracks are less likely to occur.

Table 1 〔Effect of the invention〕 The present invention can have the following effects.

(11) Abrasion resistance is poor. Because compressive residual stress is applied to the cylindrical body made of non-metallic materials such as ceramics, which are prone to breakage, cracks may occur due to thermal stress caused by heating and cooling as they start and stop during use. K becomes harder.

Productivity and workability are improved because the dimensional accuracy of the fit between the two inner and outer cylindrical bodies can be moderately adjusted.

(3) Furthermore, since the brazing filler metal acts as a cushioning material, it is possible to prevent the generation of localized high compressive force, thereby preventing the occurrence of cracks.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a part of a fuel injection nozzle equipped with a sleeper according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view showing the components of the embodiment, and Fig. 3 is a longitudinal sectional view of the same embodiment. FIG. 4 is a cross-sectional view of an IJ-tub for water purification according to the same embodiment, and FIG. 5 is a cross-sectional view showing a part of a conventional fuel injection nozzle. . DESCRIPTION OF SYMBOLS 1... Nozzle hole, 3... Cylindrical body made of non-metallic material, 4... H cylinder body made of metallic material, 5... Fuel injection nozzle body, 8...
Brazing material, 20...Sleep. Agent: Patent Attorney Akatsuki Sakama, 2 others, Figure 1, Figure 3rXi, Figure 5, 2nd Leg, 4th Session

Claims (1)

[Claims] In a sleep for a fuel injection nozzle that is inserted and fixed into the mixing chamber wall of a two-fluid mixing type fuel injection nozzle, a thin-walled metal cylinder is arranged outside a wear-resistant non-metallic cylinder,
A sleeper for a fuel injection nozzle, characterized in that a brazing material is installed in the gap between the two cylinders, and is heated and melted to fill the gap between the two cylindrical bodies.