Anyone can answer why a flow restriction or an orifice is usually placed in the primary seal vent line when considering the tandem seal design without intermediate labyrinth? Does the orifice directs the flow towards the secondary seal, given the back pressure it develops, and also 'cause secondary seal line has no nitrogen or other gas input like that in the intermediate labyrinth design? Here I saw the PSV in the primary seal vent line, but then it's a tandem seal with intermediate labyrinth.
Unless you exceed the pressure rating of the seal (which is unlikely if you are coming from discharge), a high differential pressure across the process laby shouldn't damage the dry gas seal. It would simply increase the flow through the process laby, up to a choked flow condition.
Thanks for clear important, i have a question utilizing your John crane experience, When using dry gas seal in Centrifugal compressor is mandatory? other than hazardous gas service?
There is no pressure difference in the primary seal cavity, between the process laby and the primary seal. The pressure will drop as the gas moves across the primary seal face and the process laby (or any restriction in a flowing application). The pressure entering the primary seal is a controlled parameter, controlled by the support system to a setpoint in order to maintain a specified velocity across the process laby. The pressure downstream of the process laby is approximately equal to the compressor suction pressure (if the compressor is balanced). The pressure downstream of the primary seal is approximately equal to the primary vent back pressure, which is controlled with a back pressure regulator or a check valve with a specified cracking spring pressure (usually around 5 to 10 psig in normal seal conditions).
Thanks Kevin Dwyer for this wonderful presentation, so clear and simple.
Thank you Kevin. Very useful analysis of problems, and solutions too!
Thanks Kevin.. Dry seal system simplified. Best presentation have ever seen on this subject.
Thanks Kevin Dwyer and John crane team for the crisp & clear presentation. Valuable content for DGS users.
Anyone can answer why a flow restriction or an orifice is usually placed in the primary seal vent line when considering the tandem seal design without intermediate labyrinth?
Does the orifice directs the flow towards the secondary seal, given the back pressure it develops, and also 'cause secondary seal line has no nitrogen or other gas input like that in the intermediate labyrinth design?
Here I saw the PSV in the primary seal vent line, but then it's a tandem seal with intermediate labyrinth.
tell me what happened when refrence gas and buffer gas difference pressure is high is it damage the seal
Excellent presentation
Very good explanation.
Thank you very much...
Thank you so much for this video!
tell me what happened when reference gas and buffer gas diffencal pressure is high is it damage seal?
Unless you exceed the pressure rating of the seal (which is unlikely if you are coming from discharge), a high differential pressure across the process laby shouldn't damage the dry gas seal. It would simply increase the flow through the process laby, up to a choked flow condition.
Thanks for clear important, i have a question utilizing your John crane experience, When using dry gas seal in Centrifugal compressor is mandatory? other than hazardous gas service?
What pressure difference is there between the fluid entering the primary seal and the fluid heading towards the labyrinth seal
There is no pressure difference in the primary seal cavity, between the process laby and the primary seal. The pressure will drop as the gas moves across the primary seal face and the process laby (or any restriction in a flowing application). The pressure entering the primary seal is a controlled parameter, controlled by the support system to a setpoint in order to maintain a specified velocity across the process laby. The pressure downstream of the process laby is approximately equal to the compressor suction pressure (if the compressor is balanced). The pressure downstream of the primary seal is approximately equal to the primary vent back pressure, which is controlled with a back pressure regulator or a check valve with a specified cracking spring pressure (usually around 5 to 10 psig in normal seal conditions).
@@rareoaq thank you that was neatly explained
my question again is how is the pressure difference is distributed across the seal
useful info
Can any body please send me what do it there is a loss of separation gas during centrifugal compressors operation with dry gas seal system in place