Metallic Bellows for Exhaust Pipe

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Metallic Bellows

Introduction of Metallic Bellows
Metallic Bellows (they are also called compensators) are compensating elements for thermal expansion and relative movement in pipelines, containers and machines. They consist of one or more metal bellows, connectors at both ends, and tie rods that depend on the application. They are differentiated according to the three basic types of movement: Axial, angular and lateral expansion joints.
Expansion Joins are elastic vessels that can be compressed when pressure is applied to the outside of the vessel, or extended under vacuum. When the pressure or vacuum is released, the bellows will return to its original shape (provided the material has not been stressed past its yield strength).

Features of Metallic Bellows
1. Reasonable structure, good elasticity, large range of compensation pipeline and little counterforce to the brackets of pipeline.
2. Shock absorption and noise decrease, heat and dust insulation, environmental protection and simple structure bracket.
3. The displacement can be deflected to prevent damagment caused by subsidence of connected brackets and equipment base. It can adapt itself to the centrifugal difference of pipeline installation to provide convenience to installation and maintenance.
4. Good resistance to milling, heat, aging and corrosiveness and long service life.
5. Little resistance and little weight. Each performance is better than the compensation device of other materials.
6. The temperature range of media is wide: -40300oC

Manufacture of Metallic Bellows
Welded Metallic Bellows can be fabricated from a variety of exotic metals and alloys, whereas formed bellows are limited to alloys with good elongation brass being a prime example. Welded bellows are not fabricated from brass because of its fundamentally poor weldability. Other advantages to welded bellows include compactness (higher performance in a smaller package), ability to be compressed to solid height with no damage, resistance to nicks and dents, and dramatically greater flexibility.
The welding of metal bellows is a microscopic welding process, typically performed under laboratory conditions at high magnification.
Hydroformed bellows are produced by forcing a metal tube to expand under hydraulic pressure inside a bellows-shaped mold, and assume the convoluted shape of the mold.
Electroformed bellows are produced by plating metal onto a bellows-shaped model (mandrel), and the subsequent mandrel removal by chemical or physical means.

nominal diameter DN

length L

axial displacement

horizontal displacement
mm

deflexion angle
a1+a2

mm

inch

extension mm

compression mm

32

1 1/4

95

6

9

9

15

40

1 1/2

95

6

10

9

15

50

2

105

7

10

10

15

65

2 1/2

115

7

13

11

15

80

3

135

8

15

12

15

100

4

150

10

19

13

15

125

5

165

12

19

13

15

150

6

180

12

20

14

15

200

8

210

16

25

22

15

250

10

230

16

25

22

15

300

12

245

16

25

22

15

350

14

255

16

25

22

15

400

16

255

16

25

22

15

450

18

255

16

25

22

15

500

20

255

16

25

22

15

600

24

260

16

25

22

15

700

28

320

16

25

22

15

800

32

340

16

25

22

15

900

36

370

16

25

22

15

1000

40

400

18

26

24

15

1200

48

420

18

26

24

15