Looking for a Description of Mechanical Shaft Seals

http://en.wikipedia.org/wiki/Mechanical_seal

www.applerubber.com

They have online and print seal design guides for free. If you give some specs for the shaft seal you are trying to make, I could probably give some general pointers (size, rpm, operating environment, material being penetrated, etc.).

Just go to http://www2.chicago-rawhide.com/ and examine the literature there. This is an old and established company that was recently purchased by S.K.F., who made their own line of seals.

Regards,

Ing. Robert Forbus

Basically, a mechanical seal consists of a stationary member and a rotating member. The stationary member is a circular disc fixed in the stuffing box of pump and does not move. The rotating member is fixed on the shaft and consists of a rotating seal face that bears on the stationary member, and a spring that gives flexibility during motion. The sealing is achieved between the rotating and stationary elements. The liquid being pumped cannot escape the stuffing box except through the sealing faces of stationary and rotating elements.

Different materials are used for the seal faces of stationary and rotating elements such as stellite, ceramic material, carbon ring etc. The material of rotating element being lighter than the stationary element is consumed and can be replaced. The advantage of Mechanical seal over gland packing is that the seal is in radial plane and is of much smaller area and therefore allows very little leakage. Like in gland packing a slight leakage is necessary in Mechanical seal too to prevent heat but much less than a gland packing.