Rotary Vane Pump Seals: Benefits, Types & Friction

[kandelabr]

hi,
i've read somewhere that modern vane pumps' vanes have an area of contact on the housing and the older versions had line contact. does anyone know how this is achieved? why is this better? how is this connected with friction? what types of seals are used, rubber or synthetic?
any thought is welcome.

 

[S_Happens]

Here's some basic information and terminology to get your searching started. Keep in mind that the applications and operating conditions of these pumps is hugely diverse, so seal type, material, number of seals, etc varies quite a bit as well.

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

 

[kandelabr]

wikipedia is be the first place i seek any information.
you can be sure I've noticed that article.

anything else to be told about seals?

oh I've made a mistake:
"...used, rubber or synthetic?..."
i meant rubber or metal (hard seals).

i also have an idea for non-contact sealing, but don't know how to evaluate it - there's a sketch attached. the moving surface is floating just above pump housing (distance between vane end and housing is drawn exaggerated) and supported by two steel wheels (that is, as little friction as possible). when oil would be present, i guess the liquid would seal the gap like I've drawn.
i guess.

any comments?