|
Flex-Cycling
Bellows are moved through the full rated axial travel at a rate of 10 cycles per minute for a minimum of 100,000 cycles while being subjected to the pressures listed below. No leakage is allowed.
Table 1: Flex-Cycling Test Pressures
| Number of Convolutions |
Test Pressure |
|
2
3
4
5 |
150
135
120
105 |
Pull Testing of Limitlink Limit Cables
All Limitlink cables are tested for Tensile Strength by means of a pull tester before installation. Each cable is loaded to the minimum allowable loads shown on Table 2. These values give a 4 to 1 safety factor based on the maximum operating pressure of the bellows, maximum cross-sectional area and the number of cables used in the assembly.
Table 2: Pull Test Loads
Size
Bellows
(inches) |
Allowable
Limitlink
Load (lbs.) |
|
1/2
3/4 to 1-1/2
2
3 and 4
6
8 and 10
12 and 14
12
18 to 24 |
72
150
264
360
555
750
960
1170
1350 |
Pressure Testing
Each Flexijoint is subjected to a minimum pressure of 100psi during manufacture.
Material Properties
The PTFE Bellows material shall have a minimum ultimate tensile strength of 4000psi by ASTM D1708, a minimum ultimate elongation of 300% by ASTM D1708 and a minimum specific gravity of 2.14 by ASTM D792.
Inspection for Defects
The PTFE bellows shall be free of scratches, tool marks, dents, pits, tears, inclusions or any other defects which occupy or penetrate 20% or more of the wall thickness.
All units are subjected to a high intensity light test for imperfections and inclusions.
The entire bellows surface is subjected to a 10,000 volt spark test without arcing through.
|
