JPH0353061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an air/water spray nozzle for a secondary cooling zone of slabs during continuous casting, for example. In conventional continuous casting machines, the mainstream method for secondary cooling of the slab was spray cooling of the slab using a fluid nozzle. However, with this method, excessive thermal stress is generated in the solidified shell that is solidifying and growing on the surface layer of the slab, resulting in problems such as the occurrence of surface cracks.

In contrast to spray cooling, an air-water cooling method is also known, but this air-water spray cooling method mixes pressurized air with water and converts the kinetic energy of the air into the kinetic energy of the water. The mist-like water droplets generated when the nozzle is ejected from the nozzle are used to cool the slab. In this method, the fine water droplets are scattered over a wide area by the air, and the slab can be cooled uniformly. This air-water atomizing nozzle eliminates clogging of the nozzle and is highly effective in improving the quality of steel.The present invention aims at achieving complete atomization by dividing water into smaller pieces with the minimum amount of air in such an air-water atomizing nozzle. The purpose is to bring about the state.

Two embodiments will be described below with reference to the drawings. In FIG. 1, 1 is an air pipe, and a nozzle tip 4 for air/water spraying is attached to the tip of this pipe.
Reference numeral 2 denotes a water pipe, which is bent concentrically within the air pipe 1 and has a water jet nozzle chip 3 screwed to its tip, and is arranged so that the water jet nozzle chip 3 is near the air/water spray nozzle chip 4. has been done.

As shown in FIG. 2, the water injection nozzle tip 3 includes a small-diameter cylindrical portion 3a connected to the water pipe 2;
It is composed of a large-diameter disk portion 3b facing the air-water spray nozzle tip 4 and having a larger diameter than the small-diameter cylindrical portion and forming an annular constricted portion with the inside of the air pipe 1,
For example, 4 to 8 openings 3c each having a diameter of 3 to 5 mm are equally distributed on the side surface of a small-diameter cylindrical part 3a on the air inflow side of the disc part 3b of the water injection nozzle chip 3.

A premixing chamber A is formed by the large-diameter disk portion 3b, the small-diameter cylindrical portion 3a, and the air pipe 1, and the air-water spray nozzle tip 4, the air pipe 1, and the air pipe 1 form a premixing chamber A in which water and air are mixed in advance. A mixing chamber B is formed by the diameter disk portion 3b.

Now, the accelerated air of about 5 atm maximum flowing in from the air pipe 1 collides with the disc part 3b while shearing water ejected from the opening 3c provided on the side surface of the cylindrical part 3a and mixing with the water. , mixed with the finely divided water in premixing chamber A. The water, which is further divided by the accelerated air flowing in one after another, becomes high speed as it passes through the annular constriction from the premixing chamber A while mixing with air, and flows into the next mixing chamber B at high speed.
Due to this action, the sped up air and the finely divided water are further mixed in the mixing chamber B, and the water becomes fine water droplets and becomes atomized. The water is injected into the atmosphere through the tip opening C and becomes completely atomized.

As mentioned above, after pressurized air and water are mixed in the premixing chamber A, they are accelerated in the annular constriction part and further mixed in the mixing chamber B, and then into the atmosphere through a three-stage mixing action. The water is completely atomized, allowing efficient air-water atomization with minimal air consumption.

FIG. 3 is a graph showing the relationship between the amount of water in the air-water spray nozzle and the amount of air required for atomization.

The △ mark in the figure indicates when there is no water injection nozzle chip.
The □ mark is a graph of the relationship between the amount of water and the amount of air when four openings are provided on the side surface of the cylindrical water injection nozzle chip, and the ◯ mark is a graph of the relationship between the amount of water and the amount of air when the water injection nozzle chip 3 according to the present invention is provided. As is clear from the figure, by providing the cylindrical water injection nozzle tip, the amount of air required for atomization is considerably reduced, but by using the water injection nozzle tip 3 of this patent, even less air is required. It can be seen that atomization is possible based on the amount.

FIG. 4 shows another embodiment. In this example,
A water pipe 2 is bent upstream within the air pipe 1. A water injection nozzle tip 3 is provided at the tip of the nozzle, and water is ejected facing the air flow. In this case, the water injection nozzle tip 3 is composed of a cylindrical body having a diameter approximately equal to the diameter of the large-diameter disk portion 3c, and is provided with an opening for upward water injection that is opposed to the air flow. ing.

The premixing chamber A is formed by the air pipe 1 and the end face of the water injection nozzle tip 3.

In this example as well, the water is first injected upward facing the pressurized air and premixed in the premixing chamber A, and then the water is injected downward from the annular constriction between the water injection nozzle tip 3 and the inside of the air pipe 1. It is designed to be injected into mixing chamber B. Then, water and air are mixed in the premixing chamber A and the mixing chamber B, and then the water is completely atomized into the atmosphere through three stages of mixing.

According to the present invention, first, air and water are premixed in a premixing chamber A, and a water injection nozzle tip or a cylindrical body having a large diameter disk portion between the premixing chamber A and the mixing chamber B is provided. A water injection nozzle tip is installed to generate a pressure drop, and the atomized mixture in the mixing chamber B is ejected from the opening of the air/water atomization nozzle tip, achieving efficient atomization with the minimum amount of air. It has become possible to do so.

As a result, the power cost of the compressor for generating pressurized air can be reduced, and an extremely economical air-water spray nozzle can be obtained.

[Brief explanation of drawings]

FIG. 1 shows an air/water spray nozzle according to the present invention. Figure 2 is a detailed view of the water injection nozzle chip. Figure 3 is a graph of the relationship between water volume and air volume. FIG. 4 shows another embodiment of the air/water spray nozzle. FIG. 5 is a detailed view of the water injection nozzle chip of FIG. 4. In the diagram; 1...Air piping, 2...Water piping,
3... Nozzle chip for water injection, 4... Nozzle chip for air water spray.

Claims (1)

[Scope of Claims] 1. An air/water spray nozzle in which an air/water spray nozzle chip is attached to the tip of the air pipe, and a water pipe with a water injection nozzle tip attached to the tip of the air pipe is disposed, Inserting the water spray nozzle chip near the water spray nozzle chip,
The water injection nozzle tip has a cylindrical portion with a small diameter on the water piping connection side, and the end facing the air/water spray nozzle tip has a large diameter circle so that an annular constriction can be formed between it and the inside of the air piping. As a plate part, a water and air premixing chamber is formed by the disc part, a small-diameter cylindrical part, and an air pipe, and water is supplied to the side surface of the small-diameter cylindrical part on the air inflow side from the disc part of the water injection nozzle tip. An air/water spray nozzle characterized in that the premixing chamber is provided with an opening for spraying water. 2. In an air-water spray nozzle in which an air-water spray nozzle is attached to the tip of the air pipe, and a water pipe with a water-spray nozzle chip attached to the tip of the air pipe is installed in the air pipe, the air-water spray nozzle is installed near the air-water spray nozzle tip. A water injection nozzle chip is inserted, the water injection nozzle chip is formed into a cylindrical body having a smaller diameter than the inner diameter of the air pipe, and an opening for water injection directed toward the air inflow side is provided in the cylindrical body, and An air/water spray nozzle characterized in that an annular constriction is formed between a cylindrical body and the inside of an air pipe.