This section explains the precautions to be taken and the handling of the melting post.
Even if the bellows are exactly the same, the service life that can be guaranteed will vary depending on how and under what conditions they are used. Find out what you need to know and be aware of when using the bellows.
Key points for the use of welded and formed bellows
When bellows are used, it is not only the performance of the bellows itself that is important, but also the construction of the bellows assembly to ensure that it performs to its full potential. We have the design capability that we have developed over the years. Please do not hesitate to contact us.
Choice of bellows material
Corrosion resistance and magnetism are generally considered when using bellows. If you do not have specific requirements for either of the above, please let us know. We will consider materials with short face spacing and low cost.
Interference with shafts etc.
Bellows with a clearance of at least 2 mm on each side between the inner and outer diameter of the bellows and the shaft etc. must be selected. This is to avoid a reduction in service life due to contact caused by bellows meandering or horizontal distortion. In multi-block construction, the inner diameter of the shaft can be used to support the bellows to prevent buckling, so the clearance on one side can be greater than 2 mm.
Meandering and buckling
Longer bellows can have a multi-block construction to prevent meandering and buckling due to springiness. If a shaft is provided on the bore side to prevent meandering and buckling, the clearance to the bellows bore must be large, taking into account the sliding parts.
Dust emission.
Foreign matter from the equipment can cause premature damage. Note that the horizontal position is significantly affected.
How to use bellows inexpensively
When designing bellows, we can take into account the environment in which the bellows will be used by the customer. However, if the following considerations are taken into account in the design of the customer's equipment, it may be possible to design a bellows with shorter face-to-face dimensions and at a lower cost than if the bellows were designed to specification.
The pressure inside (outside) the bellows is constant and does not fluctuate.
No pressure fluctuations. No axial perpendicular or angular misalignment when axial misalignment is desired.
The working speed should not exceed 100 mm/sec.
Welding of fittings and bellows to be carried out by us. Design in our own sizes.
Bellows handling instructions
About receiving
When the product arrives at your premises, the first thing to check is that it is exactly as ordered. Although the bellows are thoroughly inspected according to the specifications before shipping, deformation may occur due to handling during transportation to your company, so please inspect the bellows immediately upon arrival. Please open the plastic bag in an environment free from dust and dirt. (If dust or dirt gets inside the bellows or into the troughs, it may cause premature damage).
Storage
When storing the product for a long time, avoid deformation due to external forces, dust and dirt accumulation, exposure to direct sunlight and storage in a corrosive environment (high humidity, salt damage, contact with air containing corrosive substances).
Transportation
It is recommended that the product be transported in its original packaging. If the product is transported alone, it should be handled with care to avoid damage, bending or deformation due to impact.
・Mount between short surfaces
If the axial centres of the left and right (top and bottom) ends of the bellows are misaligned during installation, an offset will be added to the vertical axial displacement, resulting in a reduction in service life. To avoid this, the bellows should be set as short as possible in the operating range so that they are perpendicular to the mounting surface. However, bellows subject to atmospheric buckling may buckle during atmospheric operation. Carefully set the bellows perpendicular to the mounting surface without operating the bellows).
・Strictly anti-torsion
Bellows do not tolerate large torsional displacements.If axial displacement is applied on the compression side, the bellows will be heavily loaded, resulting in a reduced service life. In case of torsion, torsional buckling occurs and The bellows tends to be inclined towards the axial centre. Care should be taken when adjusting the bellows.
・Local deformation and buckling
Bellows perform best when all the peaks act equally. If the shaft passes through the bellows, or if the bellows is damaged by tools such as wrenches when tightening the bolt, the bellows should not be fitted easily.If a shaft passes through the bellows, it can be easily inserted and scratched.If partial deformation occurs, stress may be concentrated locally, resulting in premature failure of the deformed part. The interior cannot be inspected after installation.Care should be taken as it is not possible to inspect the inside of the unit after installation.
・Working range
The operating range (pressure, expansion/contraction, etc.) must be used within the limits specified in the specifications, catalogue or approved drawings.Use outside the operating range will not only cause premature damage but may also result in accidents.
How to use flexible tubes
Tube characteristics table |
Nominal size |
Inside diameter |
Outer diameter |
Board thickness |
Shape |
Minimum bending radius |
Bending radius |
10A |
VF |
10.5 |
15.0 |
0.25 |
U type |
40 |
105 |
VFP |
12.4 |
17.1 |
0.15 |
U type |
35 |
130 |
16A |
VF |
13.2 |
18.5 |
0.30 |
U type |
50 |
125 |
VFP |
18.7 |
24.9 |
0.20 |
U type |
50 |
140 |
25A |
VF |
25.0 |
34.0 |
0.20 |
Ω type |
70 |
180 |
VFP |
25.0 |
32.2 |
0.22 |
U type |
70 |
230 |
40A |
VF |
38.2 |
50.0 |
0.25 |
Ω type |
90 |
230 |
VFP |
41.0 |
50.5 |
0.25 |
U type |
80 |
350 |
50A |
VF |
53.3 |
66.5 |
0.30 |
Ω type |
110 |
300 |
VFP |
50.1 |
60.5 |
0.25 |
U type |
100 |
410 |
65A |
VF |
66.5 |
86.5 |
0.40 |
Ω type |
180 |
200 |
VFP |
62.8 |
85.0 |
0.40 |
U type |
150 |
250 |
80A |
VF |
78.0 |
101.0 |
0.40 |
Ω type |
200 |
250 |
VFP |
78.0 |
102.0 |
0.40 |
U type |
220 |
300 |
100A |
VF |
103.0 |
127.0 |
0.40 |
Ω type |
250 |
300 |
VFP |
100.0 |
126.0 |
0.40 |
U type |
280 |
380 |
Flexible tubes are flexible but have a standard bend radius.
Please use a radius greater than the minimum bend radius and repeat bend radius.
Glossary of bellows terms