Method for differentially pumping endblock seal cavity
View Patent ↗A system for providing a seal between a rotating part and a stationary part that comprises two seals in series separated by a cavity is disclosed. The cavity may be at low pressure and failure of either seal may be detected by a change in cavity pressure. An alarm may be triggered when cavity pressure rises above a threshold, or when it remains above a threshold for more than a predetermined period of time. In a system comprising multiple cavities, a cavity may be selectively isolated to determine if a seal associated with that cavity is experiencing a leak.
1. An apparatus sufficient to maintain subatmospheric pressure in a chamber comprising rotatable parts mechanically coupled to an exterior of the chamber, the apparatus comprising:
a static chamber portion;
a rotatable chamber portion;
a gap, a first seal and a second seal located between the static chamber portion and the rotatable chamber portion;
a cavity located between the first seal and the second seal; and
a monitoring device sufficient to monitor pressure of the cavity and to signal when pressure in the cavity exceeds a predetermined pressure for a predetermined period.
2. An apparatus sufficient to maintain subatmospheric pressure in a chamber comprising rotatable parts mechanically coupled to an exterior of the chamber, the apparatus comprising:
a static chamber portion;
a rotatable chamber portion;
a gap, a first seal and a second seal located between the static chamber portion and the rotatable chamber portion;
a cavity located between the first seal and the second seal;
a monitoring device sufficient to monitor pressure of the cavity and to signal when pressure in the cavity exceeds a predetermined pressure; and
a flow-restricting device connecting a volume at a first reduced pressure to the cavity and sufficient to create a second reduced pressure in the cavity, the second reduced pressure being higher than the first reduced pressure.
3. An apparatus sufficient to maintain subatmospheric pressure in a chamber comprising rotatable parts mechanically coupled to an exterior of the chamber, the apparatus comprising:
a static chamber portion;
a rotatable chamber portion;
a gap, a first seal and a second seal located between the static chamber portion and the rotatable chamber portion;
a cavity located between the first seal and the second seal;
a monitoring device sufficient to monitor pressure of the cavity and to signal when pressure in the cavity exceeds a predetermined pressure; and
a pressure gauge sufficient to communicate pressure in the cavity to the monitoring device.
4. The apparatus of any of claims 1 and 2 , further comprising a pressure gauge sufficient to communicate pressure in the cavity to the monitoring device.
5. The apparatus of any of claims 1 and 3 , wherein the monitoring device is sufficient to signal when pressure in the cavity exceeds a predetermined pressure for a predetermined period.
6. The apparatus of any of claims 2 and 3 , further comprising a flow-restricting device connecting a volume at a first reduced pressure to the cavity and sufficient to create a second reduced pressure in the cavity, the second reduced pressure being higher than the first reduced pressure.
7. The apparatus of any of claims 1 - 3 , further comprising a pressure gauge sufficient to measure pressure in the cavity.
8. The apparatus of any of claims 1 - 3 , further comprising at least one other cavity in communication with the cavity via a conduit, wherein the monitoring device is sufficient to monitor pressure in the conduit.