Question

List four (4) instances when you would use dual mechanical seals in preference to single mechanical seals.

Answer 1

whenever there is a requirement of maximum sealing safety we will use a double mechanical seals. as single seal is not providing zero emission, we can get the advantage from the double seal.

1) vertical mounting centrifugal pump - when this pump is used for high amount of dissolved gases it can cause serious problem with simple mechanical seal because there must be some liqiuid needed in between the seal and it can be provided by the sual mechanical seal.

2) metering pumps - metering pumps are generally used in the chemical industries where it is used for metering of toxic and flammable liquids.as dual seal is giving full protection aganst the leakage therefore it is used in this type of application where aggressive medium is used.

3)it is used over the single mechanical seals when there is sticky media is used. this is generally used in food processing and pharmaceuticals.

4)agitator - with the use of double mechchanical seal we can get high pressure and any vapourised liquid in vessel. or fluids to the environment can be eliminated.