Brief introduction of metal bellows
Composite hose is a transmission hose that is often used by everyone. In order to be able to use the hose for long-term peace of mind, in addition to daily inspection, everyone needs to do regular inspection. The inspection of composite hoses is mainly carried out from three aspects: appearance, pressure resistance and continuity. Let me explain it in detail.
- Appearance inspection of the hose
1-1 The tube surface inspection of the hose is carried out under normal conditions. Do not twist or squeeze it.
1-2 Please check whether the inner membrane is exposed due to cracks or abrasion.
The appearance of the resin paint on the upper surface of normal use will be slightly off, this will not affect the use, please rest assured.
1-3 If you can see the transparent inner film from the appearance, please update as soon as possible.
1-4 If the diameter of the hose is reduced by more than 1/2 due to wear or rust, please update it as soon as possible.
1-5 If the liquid surface will cause the tube surface to swell, please update as soon as possible.
1-6 If the pipe surface breaks due to contact with other items, please stop using it immediately.
- Appearance inspection of metal joints
2-1 Check whether the metal joint is damaged or deformed.
2-2 Check whether the joint between the hose and the connector is damaged.
2-3 Please check if the screw part is deformed.
2-4 Please check if there is any abnormality in the welding place.
- Pressure test (hydraulic test)
3-1 The test principle is to apply 1.5 times the design pressure of the hose and maintain the pressure for 15 minutes. During this time, please observe whether the entire hose including the metal part is leaking or other
Abnormal situation. The length of the composite hose will stretch about 10% under the test pressure of 10KG / cml. This situation is mostly caused by the characteristics of the material itself, not the structure
Abnormal. (In use, the pressure will be extended and the negative pressure will be shortened.)
3-2 When the hose is under pressure, micro-bubbles are generated on the surface of the hose. This is because the moisture contained in the surface coating layer is squeezed. After a period of time,
The bubbles will disappear. This phenomenon is not an abnormal phenomenon of air tightness. (This situation may also occur during use. Wipe with a dry cloth. Air bubbles will decrease or disappear.)
3-3 Composite hose is a liquid conveying pipe. Please use water pressure test when doing pressure resistance test. Do not use air pressure test to avoid damage to the hose joint.
- Continuity check
4-1 When using volatile liquids such as solvents, check the continuity between the pipe surface and the terminal metal
If there is no abnormality after inspection of appearance, pressure resistance and continuity, please use it with peace of mind.
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