JPH0443758Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a steel ball disperser for removing soot and the like adhering to the surfaces of heat exchanger tubes in a heat exchanger.

(Prior art) Conventional methods for removing dust attached to heat exchanger tubes, etc. of heat exchangers include a suit blow method using high-pressure air or steam, or a method of spraying steel balls over a group of heat exchanger tubes to remove dust attached to the heat exchanger tube surfaces. Methods such as removal are adopted.

(Problems to be solved by the invention) However, the conventional suit blowing method
The running cost of the high-pressure air or steam generator is high and uneconomical, and the steel ball dispersion method has problems such as the dispersion performance of the steel ball dispersion device greatly affecting the soot removal effect.

Conventionally, a device consisting of a square steel ball supply pipe and a spherical circular distribution plate as shown in FIG. 1 has been proposed.
This is done through a square steel ball supply pipe from above the central axis of the spherical circular dispersion plate. When the falling steel balls fall onto the spherical circular dispersion plate and scatter, the steel balls that have fallen from the central axis are directly above the central axis. However, the angle of repulsion increases as you move toward the circumference, causing the particles to scatter farther away. Note that the steel balls are supplied in the form of squares, and the steel balls that fall from around the corners fall and collide with the outer circumference of the spherical circular dispersion plate, scattering further away, and as a result, the shape of the scattering is similar to that of a steel ball. It has a similar shape to the supply pipe, that is, it spreads out in an angular shape.

Generally, a heat exchanger has a rectangular cross section, and is very similar to the dispersion form of steel balls by the present disperser. Therefore, dust can be efficiently removed by installing the minimum number of devices. In addition, the falling density of steel balls in the square steel ball supply pipe and the repulsion scattering of the spherical circular dispersion plate,
Theoretically, the dispersion density of the steel balls reaching the heat exchanger and tube handle will be similar shapes, and this situation can be determined by calculation if the curvature of the spherical circular dispersion plate, the coefficient of restitution, the falling speed of the steel balls, etc. are given. In reality, the steel balls collide with each other while traveling from the square steel ball supply pipe to the spherical circular dispersion plate, and spread out slightly before reaching the spherical circular dispersion plate. As a result, some of the particles are scattered outside the predetermined dispersion area. However, in actual machines, several dispersers are arranged next to each other, so
Steel balls scattered outside the predetermined dispersion area also effectively remove dust from other areas, but there are problems in that those scattered towards the outer circumference of the heat exchanger are not utilized effectively.

The present invention aims to provide a steel ball disperser that can reduce the amount of particles scattered outside the predetermined dispersion area and make effective use of all steel balls.

(Means for Solving the Problems) Therefore, the present invention includes a dispersion plate having an upwardly convex spherical surface above a group of heat transfer tubes of a heat exchanger, and an opening at a predetermined distance above the dispersion plate. In a steel ball dispersing device in which a steel ball supply pipe is arranged, and the steel balls are dropped and collided onto a dispersion plate through the supply pipe to be dispersed in a group of heat transfer tubes, the surface hardness of the dispersion plate is It is made by forming a predetermined hardness difference in the direction,
This is a means to solve problems.

(Function) The flight distance of a steel ball that falls onto a dispersion plate having a spherical surface and is repulsed and scattered is proportional to the surface hardness of the dispersion plate, assuming that the falling height of the steel ball and the surface curvature of the dispersion plate are constant. Therefore, when the steel balls reach the dispersion plate from the square steel ball supply pipe, the steel balls collide with each other and spread out, and as a result, the steel balls that were scattered outside the predetermined dispersion area have a surface hardness at the impact position on the dispersion plate. By arranging members with a small diameter, the flight distance of the steel balls is shortened, and the steel balls can be dispersed within a predetermined dispersion area.

(Example) The present invention will be described below with reference to the drawings. Figures 1 to 3 show examples of the present invention, Figure 1 is a perspective view of a distributor, and Figure 2 is a plane view of a distribution plate. Figure 3 shows the trajectory of the steel balls scattered by the present dispersion plate. In the figure, 1 is a spherical circular dispersion plate convex upward, and the dispersion plate 1 has an angular region 2 with high surface hardness.
It has a member consisting of in the center part, and the surrounding area 3
is made of a member with relatively low surface hardness. Further, a square tube 5 for supplying steel balls and a steel ball quantitative supply device (not shown) are provided above the distribution plate 1, and the square tube 5 holds the spherical circular distribution plate 1. A flange 6 is provided for the dispersion plate 1.
is suspended from the collar 6 by a support 7.

Next, to explain the operation based on FIG. 3, the steel balls 4 fed into the square tube 5 by an appropriate quantitative feeding device such as a rotary feeder fall naturally inside the square tube 5 and form a spherical shape. It falls and collides with the distribution plate 1 in an angular shape. Among the steel balls 4' that have fallen onto the dispersion plate 1, those close to the center scatter and fall in the vicinity, and steel balls 4'' that have fallen toward the outer circumference of the dispersion plate 1 scatter and fall further away.
The above steel ball falling position is region 2 made of a member with a low surface hardness, but the steel ball 4 falling further toward the outer circumference of the dispersion plate 1 falls in region 3 made of a material with a relatively small surface hardness. The amount of repulsion becomes small, and the particles scatter and fall in the vicinity as shown by the broken line. In addition, in Fig. 3, the surface hardness is similar to that near the center,
The scattering and falling locus of the steel ball when the surface hardness is high is shown by the dashed-dotted line.

In addition, in this example, the case where two members with different hardnesses are combined is explained, but the same material is used and subjected to charcoal quenching treatment etc. to obtain the necessary hardness difference (for example, Hv300 to 900). ), the effect is exactly the same.

(Effects of the Invention) Since the present invention is constructed as described in detail above, the drawbacks of the conventional art can be eliminated. In the operation of dispersing steel balls over a group of heat exchanger tubes to remove soot and dust adhering to the heat exchanger tubes, dispersing more of the supplied steel balls within a predetermined range greatly affects the dust removal effect. When steel balls are fed falling into a square tube, the steel balls collide with each other as they fall, spread over a predetermined range, and then fall and collide with the dispersion plate. Conventionally, scattering outside the predetermined range has been avoided. However, according to the dispersion plate of the present invention, the steel balls are prevented from scattering to areas outside the predetermined range, and the steel balls can be used effectively.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a steel ball disperser showing an embodiment of the present invention, Fig. 2 is a sectional view taken from A to A in Fig. 1, and Fig. 3 shows a scattering trajectory of a dispersion plate in an embodiment of the present invention. It is an explanatory diagram. Explanation of the main parts of the figure, 1... Spherical circular dispersion plate,
2...A region made of a member with high surface hardness, 3...
A region made of a member with relatively low hardness, 4, 4',
4″, 4... Steel ball, 5... Square tube, 6... Tsuba,
7...Support.

Claims (1)

[Scope of utility model registration request] A dispersion plate having an upwardly convex spherical surface is arranged above the heat transfer tube group of the heat exchanger, and a steel ball supply pipe with an opening is placed above the dispersion plate at a predetermined distance, and the steel balls are passed through the supply pipe. A steel ball dispersing device in which steel balls are dropped and collided onto a dispersion plate to be dispersed into a group of heat transfer tubes, characterized in that the surface hardness of the dispersion plate forms a predetermined difference in hardness in the inner and outer directions of the surface. Steel ball disperser.