JPS60152803A - Lamont type forced circulation boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to forced circulation boilers, and more particularly to improvements in Lamont forced circulation boilers.

(Technical background of the invention and its problems) As shown in FIG. It consists of a header 3b), a steam/water separation drum 4, and a circulation pump 5. Each boiler tube 2 has a different heat receiving rate depending on its position, and therefore has a different evaporation rate.

In order to make the evaporation of each tube 2 effective, it is necessary to circulate an appropriate amount of water depending on its evaporation rate. For this reason, a Lamont nozzle having an orifice is provided at the inlet of each tube 2, and by appropriately selecting the size of the orifice, water is fed in an amount corresponding to the evaporation rate.

The configuration of a conventional Lamont nozzle is as shown in FIGS. 2 and 3.

FIG. 2 is a schematic diagram showing the inlet header portion 3a of the forced circulation boiler. The inlet header 3a is connected on its upstream side to a pipe 6 for feeding boiler water from the circulation pump 4, and to its downstream side to be connected to a large number of boiler tubes 2. The conventional Lamont nozzle 7 has the functions of a strainer and four flow rate adjustment nozzles, and is removably attached to the header 3a. The function as a strainer is achieved by a large number of small holes 7a formed in the main body portion of the Lamont nozzle 7. Foreign matter such as dirt mixed into the boiler water is filtered and blocked by this strainer section. The function as a flow rate adjustment nozzle is achieved by the orifice 7b provided at the header outlet.The water amount in each tube is adjusted by the resistance when the boiler water passes through the orifice 7b, and the water supply distribution to each tube is adjusted appropriately. It will be done.

The Lamont nozzle 7 is attached to the header body by grinding. Therefore, when installing the Lamont nozzle, if dirt or the like gets caught in the fitting part 7c between the header 3a and the Lamont/Zulu 7, the short-pass water 11f, as shown in FIG.
This will result in S. As a result, an imbalance in water supply to each heat transfer surface occurs, causing tube overheating and, in the worst case, rupture. Further, the short-path water flow S causes abrasion and thinning W of both the header 3a and the Lamont nozzle 7, and in extreme cases, even causes rupture.

In this way, when installing the Lamont nozzle 7, it is necessary to take sufficient care to prevent dirt from getting caught in it.However, since the Lamont nozzle 7 is generally installed by inserting it from the upper plug, sometimes the installation may be difficult due to the fitting. It is also possible that the parts are fixed with dirt etc. attached to them. For this reason, an internal abnormality occurs in the inlet header 3a as described above, resulting in an imbalance in the water supply to each heat transfer surface, and there are many cases in which water leakage accidents due to tube overheating occur. Renewal of the header 3a and the Simont nozzle 7 required a great deal of effort and a large amount of cost, which caused problems in terms of furnace operation and repair costs.

(Object of the Invention) Therefore, an object of the present invention is to be able to appropriately adjust the water supply distribution to each tube even if dirt or the like is caught in the fitting part between the header and the Lamont nozzle, and to adjust the distribution of water to each tube. An object of the present invention is to provide a forced circulation boiler capable of preventing damage to a moving part.

(Structure of the Invention) In order to achieve this object, the present invention is characterized in that a flow rate adjustment orifice is provided in the boiler tube connected to the downstream side of the inlet header header.

That is, according to the present invention, the orifice is removed from the Lamont nozzle so that the Lamont nozzle functions only as a strainer, while the orifice is provided in the boiler tube connected to the downstream side of the header. This reduces the differential pressure between the header and the Lamont nozzle, thereby preventing further wear at the fitting portion between the header and the Lamont nozzle.

(Specific Examples of the Invention) Next, the present invention will be described in detail based on specific examples shown in the drawings.

FIG. 4 is a schematic view showing the inlet header portion of the forced circulation boiler according to the present invention, and FIG. 5 is a partially detailed view of the header portion shown in FIG. 4.

The basic configuration of the forced circulation boiler according to the present invention is substantially the same as that of the conventional Lamont type forced circulation boiler, but according to the present invention, the orifice that was conventionally attached to the output 1-1 portion of the Lamont nozzle 7 is provided in the boiler tube 2 connected to the downstream side of the header 3a instead of in the Lamont nozzle 7.

The orifices are attached to the two boiler tubes by, for example, connecting a short tube 8 provided with an orifice 8a to the boiler tube 2 by welding or the like, as shown in FIGS. 4 and 5.

2, when boiler water is fed from the circulation boiler 5 to the inlet header 3a, the water is fed into each boiler tube 2 while foreign substances such as dirt in the boiler water are filtered by the strainer 7a. Then, the water is distributed to each heat transfer surface while the amount of water is adjusted by an orifice 8a in a short pipe 8 connected to the tube 2.

(Effects of the Invention) As mentioned in Section 2, according to the present invention, the orifice conventionally provided in the Lamont nozzle is moved to the boiler tube, thereby reducing the differential pressure between the header and the tube. Yose and Lamont nozzle? It is possible to prevent short-path water flow at the fitting portion of 6., and the progress of wear in this portion can be prevented. As a result,
It is possible to avoid an imbalance in the amount of water on each heat transfer surface, and tube rupture can be prevented. In addition, the mounting of the Umont nozzle can improve work efficiency and reduce repair costs.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a general forced circulation boiler, Figure 2 is a schematic diagram of a conventional Lamont nozzle used in a forced circulation boiler, and Figure 3 is a detailed diagram of a part of the tube. FIG. 4 is a schematic view showing a header portion of a forced circulation boiler according to the present invention, and FIG. 5 is a partially detailed view thereof. 1II11 Heat transfer surface 2...Boiler tube 3ae/Inlet header 3b...Outlet header 4...Steam/water separator 5.
・Circulation pump 6・・Pipe 71I・Lamont nozzle 7a・・Small hole 7b・Fist orifice 7c・・Fitting part 8・・Short pipe 8a @ dispute orifice Patent applicant Yoshi Nagai, patent attorney representing Sumitomo Metal Industries, Ltd. Long 4. - Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A Lamont forced circulation boiler characterized by providing a flow rate adjustment orifice in the boiler tube connected to the downstream side of the header.