JPS60114582A - Prevention of corrosion in joint part of different materials - Google Patents

Abstract

PURPOSE:To prevent corrosion in the joint part of different materials for a long period of time in the stage of joining mechanically pipings, etc. consisting of different materials by using gaskets consisting of a special material. CONSTITUTION:The part near the flange 4 of a piping 2 is corroded if the natural potential in a corrosive liquid 6 of pipings 1, 2 consisting respectively of, for example, different materials is higher with the piping 1. On the other hand, gaskets 5 are made of a metallic material for which the metal having the natural potential lower than the natural potential of the pipings 1, 2 is selected. The shape of said gaskets consists of a pipe having a length (l) and a flange part. The length (l) is determined by taking the flow, electrical conductivity, corrosiveness, etc. into consideration and is made longer as the electrical conductivity is larger. The flange parts of the gaskets 5 are sandwiched by flanges 4 of the pipings and are bolted 3 to provide a satisfactory seal. Then the gaskets 5 act as a sacrifical anode to prevent the corrosion occurring in the formation of a corrosion cell and therefore the gaskets are exchanged if the thickness (t) decreases.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing corrosion of dissimilar +A/half' joints.

In the equipment used in various types of flan 1-, such as the pine for the upper head 1 water ring 1A, there are various connections of 411 that go up to the flange/flan/h/h/d.

At this (〉p) connection, corrosion (Iff
occurs.

Conventional methods to prevent this corrosion.

Methods such as painting the joints, insulating them with packing, and using insulated joints have been used, but due to defects such as deterioration of the paint and poor insulation.

It is difficult to prevent corrosion over a long period of time.

The present invention provides a method for preventing the above-mentioned corrosion, which prevents corrosion by using a special packing when joining various plant piping, etc., and is easy to install. in.

It is characterized by the fact that it can be easily replaced after being used for a certain period of time. In other words, the present invention is a method for preventing corrosion of a 4A joint between different materials, which is characterized by interposing a packing made of feed having a lower natural potential than the different material in the mechanical connection between pipes made of different materials. be.

Next, the present invention will be specifically explained using examples.

FIG. 1 shows an example in which the present invention is applied to a flange connection part.

Piping 1 and piping 2 are made of different metals (they stand outside the walls from A - in this case, if the natural potential of each metal material in corrosive liquid 6 is piping 1 (high) > piping 2 (low), then piping The part near 4i of Franz 4 of No. 2 is subject to corrosion. On the other hand, the seal 51d for corrosion prevention is made of a metal material.

Select the metal material so that the natural potential is as follows: Piping 1, 2 (high) > Packing 5 (low). The shape of the basoki 15 is as shown in Figure 1 (C).It is uniformly formed from the pipe part and the flange part (j4), and the length of the pipe part is 1>ulIIL, the flow of the body, electrical conductivity, corrosiveness, etc. Fluid i)
The higher the electrical conductivity, the longer the length is required. The flange 4 holds the flange portion of the packing 5 and fixes with the bolt 3 with good stability. Packing 5 is a sacrificial oxide that prevents IK corrosion due to the formation of a corrosive battery (because it acts as a saw, the highly corrosive It I4 medium becomes thicker than Melting 11C when used for a long time) decreases. So.

It needs to be replaced from time to time. Replacement is Fludge 4fr,
Conventionally, the corroded part was cut and replaced with a new pipe by welding, but by using Kutsugin 5 of the present invention, corrosion of the pipe can be easily removed. '4jj IL and at the same time narrow it down to exchange' 2 number reduction 75! done.

In this example, Nokutsukin 5 is made of aluminum.

Piping X was made of carbon steel, and piping Z was made of 18-8 stainless steel. In this case, as shown in Table 1, the natural potential in seawater decreases in the order of 18-8 stainless steel, carbon steel, and aluminum. , Gal ζ Nick 1 Dark Erosion 2. I = · and crevice corrosion of carbon steel were prevented.

@1 Table

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention. 1.2... Piping, 3... Bolt, 4... Flange. 5...Patzkin, 6...Corrosive liquid. dirt country

Claims (1)

[Claims] For mechanical joints such as piping made of 5°4
This is the first method of food protection, characterized by the intervention of (+g joint part).