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Method for improving durability of ductile cast iron pipe for transportation of desalination seawater

A ductile iron pipe, durability technology, applied in pipeline protection, pipeline anti-corrosion/rust protection, pipe/pipe joint/pipe fittings, etc., can solve the problem of loss of ductile iron pipe protection, ductile iron pipe blunt corrosion, affecting service Durability and service life and other issues, to achieve the effect of improving the corrosion resistance of chloride salts and sulfates, and increasing the service life

Inactive Publication Date: 2020-01-03
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the long-term water transportation environment, especially when the ductile iron pipe is used for desalinated seawater transportation, the water flow in the pipe is erosive to the cement mortar, so that the lining cement mortar layer gradually loses its protective effect on the ductile iron pipe. In turn, it will lead to depassivation and corrosion of ductile iron pipes, which will affect its service durability and service life

Method used

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  • Method for improving durability of ductile cast iron pipe for transportation of desalination seawater
  • Method for improving durability of ductile cast iron pipe for transportation of desalination seawater
  • Method for improving durability of ductile cast iron pipe for transportation of desalination seawater

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Effect test

Embodiment 1

[0027] The present invention is based on a method for improving the durability of a ductile iron pipe lining for transporting desalinated seawater, including:

[0028] mixing cement, slag, river sand and water according to the weight ratio of 6:4:13:4 to obtain the inner liner composition;

[0029] Inject the mixed inner liner composition into the ductile iron pipe and centrifuge at a speed of 2000rpm for 8 minutes until the mixture is evenly embedded in the ductile iron pipe wall;

[0030] Spheroidal graphite cast iron pipes are naturally cured for 3 hours and steam cured for 6 hours.

Embodiment 2

[0032] The present invention is based on a method for improving the durability of a ductile iron pipe lining for transporting desalinated seawater, including:

[0033] mixing cement, slag, river sand and water according to the weight ratio of 6:4:13:4 to obtain the inner liner composition;

[0034] Inject the mixed inner liner composition into the ductile iron pipe and centrifuge at a speed of 3000rpm for 5 minutes until the mixture is evenly embedded in the ductile iron pipe wall;

[0035] Spheroidal graphite cast iron pipes are naturally cured for 1 hour and steam cured for 10 hours.

Embodiment 3

[0037] The present invention is based on a method for improving the durability of a ductile iron pipe lining for transporting desalinated seawater, including:

[0038] mixing cement, slag, river sand and water according to the weight ratio of 6:4:13:4 to obtain the inner liner composition;

[0039] Inject the mixed inner liner composition into the ductile iron pipe and centrifuge at a speed of 2600rpm for 5 minutes until the mixture is evenly embedded in the ductile iron pipe wall;

[0040] Spheroidal graphite cast iron pipes are naturally cured for 2 hours and steam cured for 8 hours.

[0041] The method for improving the lining durability of the ductile iron pipe used for transporting desalinated seawater of the present invention improves the corrosion resistance performance of the ductile iron pipe against chloride salt and sulfate, so that the service life of the ductile iron pipe used for transporting desalinated seawater is greatly improved.

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Abstract

The invention discloses a method for improving the durability of a ductile cast iron pipe for transportation of desalination seawater. The method comprises the steps: mixing cement, slag, river sand and water at a weight ratio of 6:4:13:4 so as to obtain a lining-layer composition, injecting the mixed lining-layer composition into the ductile cast iron pipe, performing centrifugation at a rotationspeed of 2000-3000 rpm for 5-8 minutes until even lining of the mixture to the inner wall of the ductile cast iron pipe, performing natural curing on the ductile cast iron pipe for 1-3 hours, and performing steam curing for 6-10 hours. Through effective utilization of the slag, resistance of the ductile cast iron pipe to corrosion of chloride and sulfate can be improved, so that the service lifeof the ductile cast iron pipe for transportation of desalination seawater is improved greatly.

Description

technical field [0001] The invention relates to the field of water supply and drainage equipment, in particular to a method for improving the durability of a ductile iron pipe used for transporting desalinated seawater. Background technique [0002] Ductile iron pipes lined with cement mortar are widely used as water pipelines. The cement mortar layer lining the ductile iron pipe through the centrifugal process not only avoids the direct contact between the ductile iron pipe wall and the water flow, reduces the friction coefficient between the inner wall of the pipe and the water flow, but also reduces the high alkalinity produced by the hydration of the cement in the lining. The aggressive environment makes a dense passivation film on the surface of the ductile iron, which enhances the protective effect of the lining cement mortar layer on the ductile iron pipe. However, in the long-term water transportation environment, especially when the ductile iron pipe is used for de...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/04F16L58/06
CPCC04B28/04C04B2111/00525F16L58/06C04B18/142C04B14/068
Inventor 左晓宝邹帅汤玉娟殷光吉李向南王佳林马强江恺张林松何绍丽黄文云
Owner NANJING UNIV OF SCI & TECH