| 摘要 |
A rotating mechanical seal arrangement with an internal pump is designed as a seal based on a sealing medium in that the pump is designed as a positive displacement pump and the space which adjoins the rotating mechanical seal and accommodates the sealing medium under pressure is connected to a liquid drain passage which contains a flow resistance element, in particular a pressure-relief valve which can be set to a pressure above the pressure to be sealed off. On the side of the pump remote from the rotating mechanical seal, a low pressure is established, allowing the arrangement to be sealed off on this side by means of a simpler seal. The use of this arrangement is advantageous particularly in connection with the sealing of shafts of centrifugal pumps, the pressure of which rises more slowly at a low speed than that of the pump contained in the seal arrangement.
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