9.3 ACCOMMODATION OF THERMAL EXPANSION
Stainless steel metal hoses are slightly elastic in the longitudinal direction. It is possible to reduce the length by max. 0.6% without compromising the pressure resistance of the hose. Further compression is therefore not allowed.
The following designs are possible to compensate thermal expansion.
9.3.1 Installation plan
![](files/rattay/pictures/wellschlauch/einbaubeispiele/waermedehnung-en.png)
Straight or with displacement
Movement: lateral (not for vibrations!)
installation distance E ≈ NL · 0,994 minimum hose length FL min = 8 · a1 |
||
E | mm | installation distance in axis direction |
NL | mm | total length of the metal hose |
FL | mm | free-moving hose length |
r | mm | smallest bending radius for frequent movements |
l | mm | length of a connection part |
a | mm | total lateral path = 2 · a1 |
a1 | mm | lateral path from the middle axis (max.100 mm) |
Example 7
![Beispielberechnung](assets/images/c/9.3.1-formel-10-48abfc6f.png)
Example
Rattay stainless steel corrugated hose DN 20 Type HR I/S, on both sides screw connections made of stainless steel, Fig. 101.
Movement data
- Movement accommodation a = 60 mm
Calculation
a1 = = 30 mm
r = 170 mm see hose table
l = 79 mm see dimension table connection parts
NL = + 2 · 79 = 477 mm
FL = 477 - 2 · 79 = 319 mm
E = 477 · 0.994 = 474 mm
i.e. for installation in axis position (middle position) must be shortened by 3 mm
9.3.2 Installation plan
![9.3.2 Einbauschema 90°-Bogen Bewegung aus einer Richtung (nicht für Schwingungen!)](files/rattay/pictures/wellschlauch/einbaubeispiele/waermedehnung-90grad-eine-richtung.png)
90° elbow
Movement from one direction (not for vibrations!)
Value from bending angle table
The bending angle may not exceed max. 60°.
E1 | mm | installation distance |
E2 | mm | installation distance |
NL | mm | total length of the metal hose |
r | mm | smallest bending radius |
l | mm | length of a connection part |
a | mm | expansion accommodation |
![]() |
![]() |
bending angle |
Example 8
![Beispielberechnung](assets/images/2/9.3.2-formel-10-en-1862b142.png)
Example
Rattay stainless steel corrugated hose DN 25 Type HR I/S, on both sides screw connections made of stainless steel, Fig. 114.
Movement data
- Movement accommodation a = 60 mm
Calculation
r = 205 mm see hose table
l = 85 mm
=
= 0,293
27° see bending angle table
NL = 0.035 · 205 · 27 + 1,57 · 205 + 2 · 85 = 685.7 mm (Order length NL = 700 mm)
E1 = 205 + 205 (0.035 · 27 - 2 · sin 27°) + 85 = 297.6 mm
E2 = 205 + 2 · 205 · sin 27° + 85 = 476.1 mm
9.3.3 Installation plan
![9.3.3 Einbauschema 90°-Bogen Bewegung aus zwei Richtungen (nicht für Schwingungen!)](files/rattay/pictures/wellschlauch/einbaubeispiele/waermedehnung-90grad-zwei-richtungen.png)
90° elbow
Movement from two directions (not for vibrations!)
E1 | mm | installation distance |
E2 | mm | installation distance |
NL | mm | total length of the metal hose |
r | mm | smallest bending radius |
l | mm | length of a connection part |
a1 | mm | expansion accommodation axial |
a2 | mm | expansion accommodation lateral |
![]() |
![]() |
bending angle = + ![]() |
β | ![]() |
bending angle = + ![]() |
Example 9
![Beispielberechnung](assets/images/6/9.3.3-formel-10-en-6c4b435f.png)
Example
Rattay stainless steel corrugated hose DN 32 Type HR I/S, on both sides screw connections made of stainless steel, Fig. 101.
Movement data:
- axial a1 = 66 mm
- lateral a2 = 25 mm
Calculation
r = 260 mm see hose table
l = 96 mm see dimension table connection parts
=
= 0.253
28° see bending angle table
β = = 0.0916
18° see bending angle table
NL = 0.035 · 260 · 28 + 0.035 · 260 · 18 + 1.57 · 260 + 2 · 96 = 1,018.8 mm
E1 = 260 + 2 · 260 · sin 18° + 260 (0.035 · 28 - 2 · sin 28°) + 96 = 527.4 mm
E2 = 260 + 2 · 260 · sin 28° + 260 (0.035 · 18 - 2 · sin 18°) + 96 = 603.2 mm
9.3.4 Installation plan
![9.3.4 Einbauschema 90°-Bogen Bewegung aus zwei Richtungen (nicht für Schwingungen!)](files/rattay/pictures/wellschlauch/einbaubeispiele/waermedehnung-90grad-zwei-richtungen-2.png)
90° elbow
Movement from two directions (not for vibrations!)
E1 | mm | installation distance |
E2 | mm | installation distance |
NL | mm | total length of the metal hose |
r | mm | smallest bending radius |
l | mm | ength of a connection part |
a1 | mm | expansion accommodation horizontal |
a2 | mm | expansion accommodation vertical |
![]() |
![]() |
bending angle = + ![]() |
β | ![]() |
bending angle = + ![]() |
Example 10
![Beispielberechnung](assets/images/6/9.3.3-formel-10-en-6c4b435f.png)
Example
Rattay stainless steel corrugated hose DN 40 Type HR I/S, on both sides screw connections made of stainless steel, Fig. 114
Movement data
- Expansion accommodation a1 = 78 mm horizontal
- Expansion accommodation a2 = 23 mm vertical
Calculation
r = 310 mm see hose table
l = 95 mm
=
= 0.252
28° see bending angle table
β = = 0.0742
16° see bending angle table
NL = 0.035 · 310 · 28 + 0.035 · 310 · 16 + 1.57 · 310 + 2 · 95 = 1,154.1 mm
E1 = 310 + 2 · 310 · sin 16° + 310 (0.035 · 28 - 2 · sin 28°) + 95 = 588.6 mm
E2 = 310 + 2 · 310 · sin 28° + 310 (0.035 · 16 - 2 · sin 16°) + 95 = 698.9 mm
9.3.5 Installation plan
![9.3.5 Einbauschema 180°-Bogen Bewegung aus einer Richtung](files/rattay/pictures/wellschlauch/einbaubeispiele/180-grad-waerme-zwei-richtungen.png)
180° elbow
Movement from one direction
E | mm | installation distance |
NL | mm | total length of the metal hose |
r | mm | smallest bending radius |
l | mm | length of a connection part |
a | mm | lift |
h1 | mm | max. height of the 180° elbow |
h2 | mm | min. height of the 180° elbow |
Example 11
![Beispielberechnung](assets/images/7/9.3.5-formel-10-en-59155605.png)
Example
Rattay stainless steel corrugated hose DN 40 Type HR I/S, on both sides screw connections made of stainless steel, Fig. 114.
Movement data
- Lift a = 150 mm
Calculation
r = 205 mm mm see hose table
l = 85 mm
NL = 205 · + 1.57 · 150 + 2 · 85 = 1,049.2 mm (Order length NL = 1,100 mm)
h1 = 205 + 0.785 · 150 + 85 = 407.8 mm
h2 = 205 + + 85 = 365 mm
9.3.6 Installation plan
![9.3.6 Einbauschema 180°-Bogen Bewegung aus zwei Richtungen](files/rattay/pictures/wellschlauch/einbaubeispiele/180-grad-waerme-zwei-richtungen-23.png)
180° elbow
Movement from one direction
E | mm | installation distance |
NL | mm | total length of the metal hose |
r | mm | smallest bending radius |
l | mm | length of a connection part |
a1 | mm | total travel horizontal |
a2 | mm | total travel vertical |
h1 | mm | max. height of the 180° elbow |
h2 | mm | min. height of the 180° elbow |
Example 12
![Beispielberechnung](assets/images/3/9.3.6-formel-10-en-159c2dd7.png)
Example
Rattay stainless steel corrugated hose DN 40 Type HR I/S, on both sides screw connections made of stainless steel, Fig. 114.
Movement data
- Hub a1 = 210 mm horizontal
- Hub a2 = 175 mm vertical
Calculation
l = 89 mm
r = 310 mm see hose table
NL = 310 · + 1.57 · 210 +
2 · 89 = 1,568.6 mm (Order length NL = 1,600 mm)
h1 = 310 + 0.785 · 210 + + 89 = 651.4 mm
h2 = 310 + + 89 = 416.5 mm