Usage and precautions of metal hoses

Column：FAQ Time：2023-04-20

It is also called lateral movement or parallel eccentricity. Take the hose with flanges at both ends as an example. The two flanges keep the same distance and do Parallel transport.

Metal hoses in:

Offset Motion

Radial Motion

Axial Motion

Permanent Bend

Random Motion

Used in a certain movement in.

1 Eccentric motion

（Offset Motion）

It is also called lateral movement or parallel eccentricity. Take the hose with flanges at both ends as an example. The two flanges keep the same distance and do Parallel transport. The movement amount is represented by ± M from the centerline of the fixed end to the centerline of the free end, and T represents the total movement amount. When using a flexible hose for vibration absorption, a small eccentricity can be considered as L ≈ C. When used as a hose for thermal expansion absorption, the eccentricity is large, and the difference between L and C is large. Attention should be paid during assembly.

2 Radial movement

（Radial Motion）

Radial motion refers to the horizontal or vertical movement of the starting point of an arc when bending and assembling according to Figures A and B. It is generally referred to as a moving arc, and the amount of movement is represented by the horizontal or vertical movement distance. If the total movement T is known and the radius of curvature is chosen appropriately, the actual length L of the hose and the length K of the arc can be calculated according to the formula shown.

Total length=L+length of joint

3 Axial motion

（Axial Motion）

Axial motion refers to the displacement of a hose along the axis, expressed as the amount of expansion or contraction of the hose or the percentage of expansion or contraction relative to its original length. Hoses with mesh sleeves and S-shaped hoses are not suitable for this purpose. Seamless hoses without mesh sleeves can be used, but there are limitations at the sag point.

We recommend using expansion joints when absorbing axial displacement.

4 Permanent elbow

（Parmanent Bend）

The so-called permanent elbow refers to the use of it to simplify the connection of pipeline components, replacing ordinary elbow connections, and maintaining the same state once bent. At this point, if installed above the minimum bending radius of the hose, a portion of the movement of the piping system can be absorbed by the hose.

5 Irregular movement

（Random Motion）

The so-called irregular motion refers to the irregular motion beyond the aforementioned motion, which is prone to irregular motion when the hose is freely bent.

Precautions for assembly and use (Proper Installation)

Do not create distortion

（DO NOT TORQUE）

Twisting during assembly.
To reduce hose damage caused by twisting, it is recommended to use a loose flange or union at one end of the hose.
Sharp bending during assembly.
The hose inevitably bends during assembly, but it often bends sharply due to incorrect installation. The following figure shows three examples. When using hoses under conditions smaller than the minimum bending radius, fatigue is prone to occur, resulting in hose damage in a short period of time.

Avoid sharp twisting

(AVOID SHARP BEND)