Page 436 - Centrifugal Pumps 2E

400 Centrifugal Pumps: Design and Application

Figure 17-37. Package double opposed metal bellows seal for high temperature
(courtesy of John Crane).

Figure 17-38. Package symmetrical seal (courtesy of John Crane).

heads. If the pressure is greater than the liquid being pumped, it is operat-
ing as a double seal. If the pressure is less than the liquid being pumped,
it is operating as a tandem. This seal is designed to operate at the follow-
ing operating conditions:
* Liquid sealed: various
• Buffered liquid: oil, water, or a non-hazardous liquid compatible with
the process
• Temperature: 300°F (max)
* Speed: 3600 rpm