JP2001208505A - Method for measuring shrink quantity of corrosionproof lining layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly and accurately measure the shrink quantity of a lining layer excellent in chemical properties but high in shrinkage factor at a time of curing to easily and accurately know the addition amount of a shrink inhibitor. SOLUTION: A material for forming a pipe lining layer 2 is applied to the inner surface of a pipe 1 having a smooth inner surface to which the material does not adhere and the formed layer is cured to measure the strain quantity between the inner surface of the pipe 1 and the lining layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for measuring the amount of shrinkage of a corrosion-resistant lining layer.

[0002]

2. Description of the Related Art Metal pipes such as ductile cast iron pipes are subjected to lining treatment with a lining material made of a material having excellent chemical resistance and excellent physical strength from the viewpoint of preventing corrosion of the inside.

As such excellent lining materials, for example, unsaturated polyester resins are known. However, these unsaturated polyester resins have a large amount of shrinkage during curing, and if this amount of shrinkage is large, the lining layer is peeled off from the inner surface of the tube, or a tensile stress is always applied to the lining layer even if it does not peel off, There is a problem that peeling will occur in the future.

Conventionally, in order to prevent this, a shrinkage reducing agent such as a thermoplastic composition compatible with the crosslinkable vinyl monomer contained in the unsaturated polyester resin is added to reduce the amount of shrinkage during curing. The separation is prevented by reducing the size or slightly expanding the state.

[0005]

However, since the amount of shrinkage of the polyester resin differs depending on the temperature conditions and the amount of the resin, JIS A 62 is used as a means for measuring the amount of shrinkage.
Test methods for measuring the amount of expansion and contraction of mortar as found in Appendix 02 are not suitable.

Therefore, to know the amount of the shrinkage reducing agent,
It is difficult to accurately know the shrinkage amount of the lining layer, and it is difficult to set the amount of the additive. The present invention solves the above-mentioned problems, enables the amount of shrinkage of the lining layer to be quickly measured, and easily adds the amount of the anti-shrinkage agent,
The task was to know exactly.

[0007]

According to the method for measuring the amount of shrinkage of a corrosion-resistant lining layer according to the present invention, a material for forming a corrosion-resistant lining layer is applied to the inner surface of a tube having a smooth inner surface to which the material does not adhere, and the layer is cured. Thereafter, the amount of strain between the inner surface of the pipe and the lining layer is measured.

According to the above method, when a corrosion-resistant lining material such as a resin is applied and then cured, the lining layer is easily peeled off from the inner surface of the pipe, and the shrinkage is easily and accurately measured by measuring the amount of distortion during the lining layer. It becomes measurable.

[0009]

Next, an embodiment of the present invention will be described. Embodiment 1 FIG. 1 is a longitudinal sectional view showing a method for measuring a shrinkage amount of a corrosion-resistant lining layer according to Embodiment 1, and FIG. 2 is a transverse sectional view of the same.

In FIG. 1, reference numeral 1 denotes a pipe having a smooth inner surface made of a material generally used as a corrosion-resistant lining material of a cast iron pipe to which an unsaturated polyester resin does not adhere, for example, polyethylene.

Reference numeral 2 denotes a layer made of a material for forming a corrosion-resistant lining layer to be tested, for example, a lining layer made of the above-mentioned unsaturated polyester resin. To form the corrosion-resistant lining layer, the tube 1 is rotated, and the material 2 for forming the corrosion-resistant lining layer is uniformly dispersed on the inner surface of the tube by centrifugal force to form a cured film.

Therefore, even if the pipe 1 is a polyethylene pipe having a property to which the unsaturated polyester resin does not adhere, a film of the resin can be formed on the inner surface of the pipe. When the lining layer is formed on the inner surface of the tube 1 in this manner, the lining layer shrinks with curing, and eventually peels off from the inner surface of the tube 1 as shown by a dotted line in FIG. Although the contracted state of the coating film is exaggerated in FIG. 2 for the sake of explanation, it does not actually shrink so much.

Therefore, when the corrosion-resistant layer 2 is peeled off from the inner surface of the tube 1 after curing, if the interval t of the gap is measured, this becomes the amount of distortion, and the amount of shrinkage and the shrinkage ratio can be determined based on t.
That is, assuming that the inner diameter of the tube 1 is D, the contraction amount τ is τ = πD−π (Dt) = πt, and the contraction ratio φ is φ = πt / πD = t / D. The rate turns out.

Based on these values, the amount of shrinkage reducing material added is calculated, and the actual amount of shrinkage of the corrosion-resistant lining resin is adjusted so as to be zero or slightly expanded. Embodiment 2 FIG. 3 is a longitudinal sectional view showing a method for measuring the amount of shrinkage of a corrosion-resistant lining layer according to Embodiment 2, and FIG. 4 is a transverse sectional view of the same.

In FIGS. 3 and 4, the same members as those of the first embodiment are denoted by the same reference numerals, and the detailed description is omitted. In FIG. 3, reference numerals 3... 3 denote strain gauges, and a plurality of strain gauges 3.

Reference numeral 4 denotes an output line of the strain gauge, which penetrates the wall of the tube 1 and is led out of the tube. The strain force applied to the strain gauge 3 via the output line 4 can be electrically measured by the strain gauge 5.

Then, a layer 2 made of a material for forming a corrosion-resistant lining layer to be tested is formed on the inner surface of the tube 1 to which the strain gauge 3 has been temporarily fixed and hardened. As in the first embodiment, the film is formed by rotating the tube, uniformly dispersing it by centrifugal force, and curing the film.

When the lining layer is cured, the strain gauge 3
3 are fixed to the hardened lining layer, and the strain gauges 3. Therefore, as shown in FIG. 4, the strain gauges 5 are sequentially connected to the respective strain gauges 3... 3 to measure the strain, and the values are averaged to measure the strain amount.

When it is necessary to know the strain direction and the strain amount of the lining layer in as much detail as possible, the mounting posture of the large number of strain gauges 3 may be varied in the axial direction of the pipe, the circumferential direction of the pipe, or the intermediate angle direction thereof. Paste in different directions,
Measure the strain in each direction.

The shrinkage and shrinkage of the lining layer are obtained from the obtained values, and the amount of shrinkage reducing material added is determined.

[0021]

As described above, according to the method for measuring the amount of shrinkage of a corrosion-resistant lining layer of the present invention, the shrinkage of a corrosion-resistant material which is excellent in chemical stability but shrinks upon curing, which may cause peeling. Since the ratio can be accurately grasped and the amount of the shrinkage reducing agent added can be set appropriately, there is an effect that an anticorrosive paint having excellent chemical stability can be used without fear of peeling.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a method for measuring a shrinkage amount of a corrosion-resistant lining layer according to a first embodiment.

FIG. 2 is a transverse sectional view of the same.

FIG. 3 is a longitudinal sectional view showing a method for measuring a shrinkage amount of a corrosion-resistant lining layer according to a second embodiment.

FIG. 4 is a transverse sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tube made of material to which resin paint does not adhere 2 Corrosion-resistant lining layer 3 Strain gauge 4 Output line of strain gauge 5 Strain gauge

Claims (1)

[Claims] 1. A material for forming a corrosion-resistant lining layer is applied to the inner surface of a tube having a smooth inner surface to which the material does not adhere, and after stratification and curing, the amount of distortion between the inner surface of the tube and the lining layer is measured. A method for measuring the amount of shrinkage of the corrosion-resistant lining layer.