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US 10,871,167 B2Granted
Reduced emission gas seal
AssigneeJohn Crane UK Limited
InventorsIan Martyn Goldswain, Kanza Amanullah, Raphael Rouillon
Life of this patent
Estimating the term…
Abstract
A dry gas mechanical seal system configured to inhibit the emission of process gas. The mechanical seal system having tandem first and second stage seals, and a single separation gas supply subsystem configured to direct a supply of separation gas from an inlet through interfacing portions of the first stage seal into a process cavity and from the inlet through the interfacing portions of the second stage seal and out through an outlet to the atmosphere, thereby inhibiting the emission of process gas between a compressor housing and a rotating compressor shaft.
Claims30
A mechanical seal system for a compressor operating on a process gas in a process cavity at a process cavity pressure, the mechanical seal system comprising:
- a mechanical seal including a rotating ring operably coupled to a compressor shaft, and a stationary ring operably biased towards the rotating ring by a biasing mechanism operably, coupled to a compressor housing, the rotating ring defining grooves that during normal operation are configured to pressurize gas passing between interfacing portions of the rotating ring and the stationary ring to partially counteract a biasing force of the biasing mechanism;
- a dense barrier gas supply subsystem configured to direct a supply of dense barrier gas from an inlet through the interfacing portions of the rotating ring and the stationary ring at a pressure below the process cavity pressure, during normal operation the grooves of the mechanical seal configured to pressurize the dense barrier gas to a pressure above the process cavity pressure to promote an upstream flow of the dense barrier gas from an inner diameter of the mechanical seal to an outer diameter of the mechanical seal and into the process cavity and to maintain an interface gap between the interfacing portions of the rotating ring and the stationary ring;
- and
- a starting mechanism configured to supply an additional supply gas into the interfacing portions of the rotating ring and the stationary ring during a starting operation to provide an initial gap between the interfacing portions until the rotating ring reaches a rotational speed at which the interface gap between the interfacing portions is sustainable.
1 more element
A non-contacting, dry gas, tandem mechanical seal system having a starting mechanism configured to artificially provide an initial gap between interfacing portions of a first stage seal during a starting operation, the mechanical seal system comprising:
- a first stage seal including a rotating ring operably coupled to a compressor shaft, and a stationary ring operably biased towards the rotating ring and operably coupled to a compressor housing, the rotating ring defining grooves that during normal operation are configured to pressurize gas passing between interfacing portions of the rotating ring and the stationary ring;
- a dense barrier gas supply subsystem configured to direct a supply of dense barrier gas through the interfacing portions of the rotating ring and the stationary ring at a pressure below a process cavity pressure of a process cavity, during normal operation the grooves of the first stage seal configured to pressurize the dense barrier gas to a pressure above the process cavity pressure to promote an upstream flow of the dense barrier gas from an inner diameter of the first stage seat to an outer diameter of the first stage seat and into the process cavity and to maintain an interface gap between the interfacing portions of the rotating ring and the stationary ring;
- and
- a starting mechanism configured to supply an additional supply of gas into the interfacing portions of the rotating ring and the stationary ring during a starting operation to artificially provide an initial gap between the interfacing portions until the rotating ring reaches a rotational speed at which the interface gap between the interfacing portions is sustainable.
1 more element
A method of artificially providing, an initial gap between interfacing portions of a mechanical seal during a starting operation, the method comprising:
- providing a direct supply of dense barrier gas through interfacing portions of a rotating ring and a stationary ring of mechanical seal at a pressure below a process cavity pressure, wherein during normal operation grooves defined by the mechanical seal are configured to pressurize the dense barrier gas to a pressure above the process cavity pressure of a process cavity to promote an upstream flow of the dense barrier gas from an inner diameter of the mechanical seal to an outer diameter of the mechanical seal and into the process cavity to maintain an interface gap between the interfacing portions of the rotating ring and the stationary ring;
- and
- providing an additional supply of gas into the interfacing portions of the rotating ring and the stationary ring during the starting operation to artificially provide the initial gap between the interfacing portions until the rotating ring reaches a rotational speed at which the interface gap between the interfacing portions is sustainable.
A mechanical seal system for a compressor operating on a process gas in a process cavity at a process cavity pressure, the mechanical seal system comprising:
- a mechanical seal including a rotating ring operably coupled to a compressor shaft, and a stationary ring operably biased towards the rotating ring by a biasing mechanism operably coupled to a compressor housing, the rotating ring defining grooves that during normal operation are configured to pressurize gas passing between interfacing portions of the rotating ring and the stationary ring to partially counteract a biasing force of the biasing mechanism;
- a dense barrier gas supply subsystem configured to direct a supply of dense barrier gas from an inlet through the interfacing portions of the rotating ring and the stationary ring at a pressure below the process cavity pressure, during normal operation the grooves of the mechanical seal configured to pressurize the dense barrier gas to a pressure above the process cavity pressure to promote an upstream flow of the dense barrier gas from an inner diameter of the mechanical seal to an outer diameter of the mechanical seal and into the process cavity and to maintain an interface gap between the interfacing portions of the rotating ring and the stationary, ring;
- and
- a starting mechanism configured to supply the process gas from inside the compressor into the interfacing portions of the rotating ring and the stationary ring during a starting operation to provide an initial gap between the interfacing portions until the rotating ring reaches a rotational speed at which the interface gap between the interfacing portions is sustainable.
1 more element
A method of operating a mechanical seal operation, the method comprising:
- providing a direct supply of dense harrier gas to a harrier gas chamber in the seal and through interfacing portions of a rotating ring and a stationary ring of the mechanical seal at a pressure below a process cavity pressure of a process cavity, wherein during normal operation grooves defined by the mechanical seal are configured to pressurize the dense harrier gas to a pressure above the process cavity pressure to promote an upstream flow of the dense barrier gas from an inner diameter of the mechanical seal to an outer diameter of the mechanical seal and into the process cavity to maintain an interface gap between the interfacing portions of the rotating ring and the stationary ring;
- reducing an amount of the dense barrier gas supplied to the harrier gas chamber;
- providing an additional supply of process gas into the interfacing portions of the rotating ring and the stationary ring to provide the interface gap between the interfacing portions when the rotating ring is below a rotational speed at which the interface gap between the interfacing portions is sustainable.
Dependencies are inferred from the claim text.