JPS6221589B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When it is necessary to apply a corrosion-resistant material to the inner surface of a steel pipe or the like, if mortar is conventionally applied based on the experience and intuition of an operator, there is a risk of lack of uniformity.

The present invention was made especially for the purpose of lining a large-diameter pipe with high quality.When the pipe is rotated and mortar is applied to the inner surface, the mortar is subjected to centrifugal force, resulting in a high-density lining on the pipe surface. A high quality lining material with a smooth surface can be obtained.

Conventionally, in the case of large-diameter pipes, construction technology for mortar lining has not been established, and other lining materials, such as coal tar, which are easy to handle, are generally used. However, in the case of waterworks, the dissolution of tar is a pollution problem for such lining materials, and in the case of chimneys, there are various problems such as deterioration of the lining due to heat and chemical reactions.Although it is easy to handle, it is difficult to use as a lining material. There are also disadvantages of
There is a problem in performance compared to the quality of cement mortar. Therefore, by changing the way centrifugal force is applied, high-quality lining can be achieved to overcome the disadvantage of mortar lining materials, which are poor workability.

To explain the present invention by way of an example, Fig. 1 is a perspective view showing the concept of a method of applying mortar on the inner surface of a pipe, in which 1 is a member to be lined, 2 is a lining supply device, and 3 is a lining material applied into the pipe. 4 is a power supply that rotates the member to be lined; 5 is a mechanism that transmits the power to the tube; and 6 is a roller that assists the rotation of the tube. When the lining material is conveyed to the inner surface of the tube while it is rotating at a low speed, the lining material is piled up on the inner surface of the tube, as shown in FIG. 7 indicates the pipe body, 8 indicates the lining material at the moment it is introduced, 10 indicates the highest point ho of the lining material, and 1
1 indicates the contour lines of the lining material 8. FIG. 3 shows a state in which lining has been completed, and reference numeral 11 indicates a contour line ((the entire surface is at the same level) at an arbitrary point on the surface of lining material 8 after lining has been completed.

In FIG. 2, 13 indicates the force that the lining material receives, and 14 indicates the direction in which the lining material 8 moves when it receives the centrifugal force 13. To explain the phenomenon from the state shown in Fig. 2 to the state shown in Fig. 3, the introduced lining material is subjected to centrifugal force 13 by rotating the pipe body, and the top 10 of the lining material at the time of introduction increases the rotation. Accordingly, the height h ₀ of the apex 10 gradually decreases and moves to h ₁ . When h ₁ is reached, the lining is balanced in all directions and its movement is stationary.

This kind of diffusion occurs when centrifugal force is applied, but
When the lining material is introduced, it will spread in the circumferential direction due to its own weight at low rotations, and as the rotation increases, it will spread due to centrifugal force. This does not mean that a different lining can be obtained. Furthermore, if the rotation is increased and too much centrifugal force is applied, the water and aggregate in the lining material will separate, and the fluidity will decrease, making it increasingly difficult for the lining material to spread.

Regarding the rotation and diffusion force of the tube body, we will consider the centrifugal force and diffusion force of the lining material by dividing the rotation speed into low speed rotation, medium speed rotation, and high speed rotation.

When the lining material is carried into the tubular body and the tubular body is rotated, the lining material stays at one point on the tubular body, and considering the minimum rotational speed at which the lining material rotates with the tubular body, the centrifugal force at this time is defined as F ₀ . Below this speed is called low speed rotation, above this speed is called medium speed rotation, and when the lining material is turned so fast that it does not spread to the inner wall of the pipe, it is called high speed rotation.

First, during low-speed rotation, the lining material tends to fall down along the inner surface of the cylinder when the wall surface is lying down as the tube rotates, but since the cylindrical wall is rotating, the lining material remains at the same position on the inner surface of the cylinder. In this state, when the lining material reaches the ceiling of the tube, it peels off and falls.
Let F ₁ be the limit of centrifugal force that does not cause peeling and falling.

At F ₁ or below, almost no centrifugal force is generated, and as the lining material moves along the inner surface of the tube according to gravity as it rotates, the lining material just crawls along the circumferential inner surface, and no diffusion due to centrifugal force occurs. do not have. _F1
In the state of ~F ₀ , the lining material conveyed into the pipe rotates slowly as it slides down the pipe surface when rotating upward, and slides down the pipe surface faster than the movement of the pipe when rotating downward. As a result, the lining material undergoes a relative movement and a significant spreading in the circumferential direction.

When the centrifugal force associated with rotation becomes larger than F ₀ , the lining material moves in the same manner as the tube, and slowly spreads back and forth due to the centrifugal force. In this case, the diffusion rate depends on the quality of the lining material and the centrifugal force.

When the rotation becomes high speed, the lining material does not spread and acts similar to a centrifugal separator, the aggregate and water in the lining material are separated, and the cement and aggregates with heavy specific gravity are firmly attached to the inner surface of the tube. , water with a light specific gravity adheres to the surface of cement and aggregate. This moisture on the surface of the lining becomes free surface water, which has significantly less viscosity than mortar, so surface water
The movement is similar to the state of F ₁ to _{F 0} , and the surface of the mortar, which has become smooth, is washed away along with the vibrations generated when the tube rotates, and the erosion is repeated, and surface water accumulates on the eroded cross section, causing further erosion. It makes it bigger. Therefore, it is necessary to apply centrifugal force to suppress the erosion caused by this surface water.

EXAMPLE An example of the results of various experiments will be explained with reference to FIG.

This example is for a large pipe with a diameter of 1.8M, and shows the optimal construction conditions when actually constructed. Of course, if this construction method is adopted, construction can be performed even under conditions other than the optimum conditions.

A, B, and C are actual construction examples, and A is for providing mortar injection and movement for dispersing mortar mainly in the circumferential direction, and the tube circumferential velocity is 10.
It rotates for about 10 minutes at a circumferential speed of about 20 Km/h or less, and then B mainly gives horizontal diffusion, and the circumferential speed of the tube is about 20 Km/h or less.
It is rotated for about 5 to 10 minutes at a speed of less than Km/h. C is a state in which water in the mortar is sufficiently separated and the free surface does not corrode the mortar surface.
It rotates at a circumferential speed of about 80 km/h for about 20 minutes.

As a result of the above experiment, the optimum conditions differ depending on the degree of mixing of the mortar, but in the range shown by the broken line, A is a circumferential speed range of 1 to 20 km/h from A' to A'', and B is a circumferential speed range from B' to A''. B″ ranges from 5 to 50 Km/h, C includes C′ to C″ range from 30 to 120 Km/h.

When the rotational speed is expressed in terms of centrifugal force, the relationship between the two is expressed as Fi=W/g·V ² /Ri. Fi is the centrifugal force, Ri is the radius of the tube, Vi is the circumferential velocity, W is the own weight, and g is the acceleration of gravity (981 cm/sec ² ).

Therefore, the lining construction conditions for each pipe diameter may be determined based on the magnitude of gravity G (gal) applied to the pipe.

G=V ² /g・Ri (cm/sec ² ) Vi=√・cm/sec, and if G is a constant value, the circumferential speed to be given is radius Ri
It can be easily obtained from the above formula.

Figure 5 is a representation of Figure 4 in G (gal), and the states of A, A', A'' in Figure 4 are expressed as a, a', a'' in Figure 5, and B, B. ′、B″、C、C′、
C'' is represented by b, b', b'', c, c', c'', respectively.
At rotational speeds A, A', and A'', centrifugal force is generated only slightly below 4 gal, as shown in Figure 5 a, a', and a'', so it is applied only in the circumferential direction of the tube. It acts on the diffusion of

In addition, the range b that provides diffusion in the horizontal direction is approximately 20 gal or less and approximately 5 gal, and the rotation c required for moisture diffusion is
Give 10-150 gal.

As is clear from the above description, the present invention involves carrying a lining material into a tube with the purpose of uniformly applying mortar to the inner surface of the tube, and rotating the tube at a low speed to spread the mortar in the circumferential direction of the tube. After that, the tube body is rotated at a medium speed to spread the mortar in the horizontal direction, and the thickness of the mortar on the inner surface of the tube is made uniform. Since this is a cement mortar lining construction method that separates moisture, it is now possible to uniformly apply mortar inside large-diameter pipes, which previously could not be done satisfactorily, meeting the gradually increasing demand for mortar-lined pipes. By carrying out the present invention, it is a pipe lining method that can be easily applied and has high productivity. In the manufacturing process, the mortar is spread to a uniform thickness on the surface of the pipe by rotating at low to medium speeds, and at high speeds, water is separated and the free surface water is rotated to the extent that it does not corrode the mortar surface. The finish is uniform and clean.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the concept of an embodiment for explaining the present invention. FIG. 2 is a side view and a plan view showing the state in which the lining material has been introduced into the inner surface of the tube. Figure 3 is a side view showing the state in which the same lining material is diffused;
FIG. FIG. 4 is a chart showing the tube circumferential speed versus operating time, illustrating an experimental example. FIG. 5 is a graph showing gravity versus operating time giving FIG. DESCRIPTION OF SYMBOLS 1... Member to be lined (pipe body), 2... Lining material supply device, 3... Lining material carrying device, 4... Rotating power source, 5... Power transmission mechanism, 6
... Rotation auxiliary roller, 7 ... Pipe body, 8 ... Lining material, 10 ... Maximum point of lining material, 11 ...
Contour line, 13...Centrifugal force of lining material, 14...
...diffusion direction.

Claims (1)

[Scope of Claims] 1. A method for constructing mortar lining inside a large-diameter steel pipe while rotating the pipe, which includes the following steps. (a) Process of transporting lining material into the pipe. (b) A process in which the mortar is spread in the circumferential direction of the inner surface of the tube by rotating the tube at a circumferential speed such that the lining material does not stay at one point due to centrifugal force. (c) A process in which mortar is spread in the horizontal direction by increasing the rotational speed of the tube and rotating the tube at such a circumferential speed that the lining material remains on the circumferential inner surface of the tube due to centrifugal force. (d) A process in which the peripheral speed of the tube is further increased to separate the cement, aggregate, and water in the mortar.