Sermatech Ethylene
 

Vacuum Ratings for Flexijoint® Bellows
 

The vacuum rating of a Flexijoint will decrease with increasing temperature, diameter and number of convolutions. The table below gives the maximum working temperature for a Flexijoint operating at full vacuum.

Vacuband™ vacuum rings enable Flexijoints through 42" diameter to be rated for full vacuum at temperatures to 350°F. The Vacuband is a metal hoop inserted into the root of the convolution. Metal selection is based on the

customer's specification. Material such as Tantalum, Hastelloy, Monel, stainless steels, Nickel and Zirconium are commonly used. Consult the factory for sizes or temperatures not listed.

Maximum Temperature (°F) for Full Vacuum Service
(without Vacubands)

Size

Number of Convolutions

2 3 4 5 6 7 8 9 10
1 450 450 450 425 400 400 400 400 400
1-1/2 450 450 450 425 400 400 400 400 400
2 450 450 450 425 400 400 400 400 400
2-1/2 425 425 425 400 400 350 350 300 300
3 425 425 400 350 350 300 300 250 250
4 400 400 350 300 300 250 250 200 200
5 400 350 300 250 250 200 200 150 150
6 320 300 250 200 200 150 100 – –
8 250 200 200 150 100 – – – –
10 200 200 150 100 – – – – –
12 150 120 100 – – – – – –
14-16 120 – – – – – – – –
18-24 100 - - - - - - - -