About usage environment｜Products｜IRIE KOKEN CO., LTD.

About usage environment

Name	Description
Internal vacuum	Conditions under which the inside of bellows is vacuum and the outside is atmospheric pressure
External vacuum	Conditions under which the inside of bellows is atmospheric pressure and the outside is vacuum
Internal pressure	State in which a pressure higher than the outside of bellows is applied to the inside, or its pressure
External pressure	State in which a pressure higher than the inside of bellows is applied to the outside, or its pressure
Equal pressure	State in which equal pressure is applied to the inside and outside of bellows * Normally, both the inside and outside are atmospheric pressure in this state * This state is frequently used during maintenance
Fluctuating pressure	Pressure changes in operating cycle, which greatly affects life performance depending on condition * There are cases when it occurs at the time of stop bellows or due to volume changes caused by expansion/contraction, etc.
Average pressure	Average pressure in the case where fluctuating pressures are applied; assuming that the external pressure is negative and the internal pressure is positive: (maximum pressure + minimum pressure)/2
Pressure fluctuation width	Pressure broadening in the case where fluctuating pressures are applied; assuming that the external pressure is negative and the internal pressure is positive: \|maximum pressure - minimum pressure\|

Name	Description
Working temperature	Temperature at which the bellows is used, the characteristics of which are dependent on the materials used. With increasing temperature, the life performance deteriorates. SUS304(L), SUS316(L) --- 500°C or less AM350 equivalent --- 450°C or less Hastelloy®C-22 --- 800°C or less
Baking	Treatment by raising temperature, which is commonly performed in the vacuum industry with a heater in order to remove moisture and impurities in vessels. The commonly-used temperature is about 100 to 250°C.
Working fluid	Gas, liquid, or vapor filled inside or outside the bellows. Corrosive fluid is taken into consideration when bellows material is selected.