JPH01150097A - Ceramic lining bent pipe - Google Patents

Abstract

PURPOSE: To prevent local wear and damage so as to be used for a long time by providing well-balanced lining wear resistance to an entire bent portion of a ceramic-lined bend used in the pipe system for pumping slurry or the like. CONSTITUTION: A ceramic lining having more excellent wear resistance than ceramics in other regions is applied in the region where the collision angle θagainst a pipe wall for pumping particles, which can be expressed by the formula θ=tan<-1> (2n)<112> /(n-1/2), is 10-30 degrees in the bend for pumping powder and particles with ceramic lining L applied on an inner surface thereof. In the formula, n equals to R/D, where R is the curvature radius of the pipe axis of the bend, and D is an outer diameter of the bend.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic-lined bent pipe used as a bent pipe in a pipe for transporting powder, slurry, etc.

[Conventional technology]

Metal pipes and synthetic resin pipes are used as pipe materials for pipes for transporting powders, slurries, etc. (hereinafter simply referred to as "powder transport pipes"), but the inner wall surface of the bent pipe in these pipes is difficult to transport particles. Since wear due to collisions is likely to occur, bent pipes with ceramic lining on the inner surface of the pipe are used. The ceramic lining is generally formed by adhering ceramic tiles to the inner surface of the pipe, or by connecting short ceramic torus bodies formed into a cylindrical shape and installing them inside the pipe. As the ceramic, alumina (Azzoz) is mainly used.

[Problem that the invention seeks to solve]

However, conventional ceramic lined bent pipes are susceptible to local wear damage to their linings. This is because the entire inner surface of the bent pipe is made of the same ceramic material.

In other words, although the progress of wear on the lining differs depending on the collision angle of transported particles passing through a bent pipe with the pipe wall surface, material design has not been done that takes into account the relationship between the collision angle and the amount of wear, so the lining area The overall wear resistance is not balanced, and wear in specific areas progresses over long-term use. As a result, damage accidents such as local openings occur even though wear in other areas is minor.

The present invention provides an improved ceramic lined bent pipe to solve the above problems.

[Means and effects for solving the problems] The ceramic lined bent pipe of the present invention has the following formula: θ-tan-IGn<n-1/2)-(1) [wherein,
n = R/D, where R is the radius of curvature on the tube axis of the bent tube, and D is the outer diameter of the bent tube], and the collision angle (θ) of the transported particles with the tube wall is 10 to 30'. It is characterized by a ceramic lining that is more resistant to wear than ceramic linings in certain areas.

In the ceramic lined bent pipe of the present invention, the ceramic lining has higher wear resistance than the ceramic lining in other areas in the area where the collision angle (θ) calculated by the above equation (1) is 10 to 30 degrees. This is because the lining in that area wears out faster than the lining in other areas.

FIG. 1 shows an example of a ceramic lined bent pipe. (P) is a metal tube, and (L) is a ceramic lining formed on the inner surface of the metal tube (P). In this bent pipe, the region where the collision angle (θ) calculated by the CI) formula is 10 to 30 degrees is, for example, (A) and (
B), and the collision angle (θ) of the remaining area is 10°
In the case of smaller or bent pipes exceeding 30°, a ceramic with higher wear resistance is applied to the inner surface of the pipe wall in the areas (A) and (B).

FIG. 2 shows the results of a wear test of ceramic lining in a region where the particle collision angle (θ) is 10 to 30 degrees in a bent pipe of a slurry transport pipe. The bent pipes tested had three types of ceramic lining materials: silicon carbide, silicon nitride, or alumina, all of which had an outer diameter (
D) is 600mm.

The slurry also contained 10% silica sand (particle size 2-5 mm), and the flow rate was 15 m/sec. The wear resistance of the ceramic lining of each bent pipe was compared based on the wear resistance time (Hr/m [11). As shown in the figure, the wear time of the silicon carbide lining in this wear test was approximately 52 Hr/mn, which is approximately 1.7 times more wear resistant than that of the alumina lining, which was 30 Hr/in. The wear resistance of the bare lining is 4611 r/mm, which is a high wear resistance similar to that of silicon carbide lining. Therefore, in the bend pipe of this slurry transport pipe, the particle collision angle (θ)
By applying silicon carbide or silicon nitride lining to the area where the angle is 10 to 30° and applying alumina lining to other areas, the wear resistance of each area of the lining layer is well balanced, and local This makes it possible to prevent damage and accidents caused by holes in the pipe wall. Of course, the above is just an example, and the selection and combination of ceramic lining materials, lining layer thickness, etc. in the region where the particle collision angle (θ) is 10 to 30 degrees and in other regions are determined by the usage environmental conditions, such as the transport fluid. This should be determined individually depending on the type of water, flow rate, shape of the bend pipe, etc.

〔Example〕

As a bent pipe for silica sand-containing slurry transport piping, a bend in which a lining layer of silicon carbide ceramic tiles is formed in the area where the particle collision angle (θ) is 10 to 30'' and a lining layer of alumina ceramic tiles is formed in the other areas. A pipe (lining layer thickness: 4 m, pipe outer diameter 700 mm) was used. The silica sand content of the slurry was 15%, and the flow rate was 20 m/sec. Used for 8 months (transport flow rate: 256 tons)
I. Later, the degree of lining wear on the inner surface of the bend pipe,
As a result of comparison with a conventional bent pipe (lining material: alumina ceramic tile, layer thickness 4 mm) used under the same conditions, the amount of lining wear of the bent pipe of the invention example was approximately 0% less than that of the conventional bent pipe. It was observed that the product remained in a state where it could be used for a long period of time.

〔Effect of the invention〕

The ceramic lined bent pipe of the present invention has well-balanced lining abrasion resistance over the entire bent part, so it does not suffer from localized wear damage unlike conventional products, and can be used stably over a long period of time. This makes it possible to prevent accidents such as punctures, and to greatly reduce piping maintenance.

[Brief explanation of the drawing]

FIG. 1 is an axial sectional view showing an example of a bent pipe with ceramic lining, and FIG. 2 is a graph showing the results of a wear test of the ceramic lining. P: Metal pipe, L: Ceramic lining, F: Transport fluid.

Claims (1)

[Claims] (1) In a bent pipe for transporting powder and granular materials with ceramic lining on the inner surface of the pipe, the following formula: θ: tan^-^1√(2n)/(n-1/2) [where n= R/D, where R is the radius of curvature of the bend tube on the tube axis, and D is the outer diameter of the bend tube. The collision angle (θ) of the transported particles with the tube wall is 10 to 30 degrees. A ceramic lined bent pipe characterized in that a ceramic lining having superior abrasion resistance than ceramic lining in other areas is applied to the area.