Valve with low friction coating

A method of controlling the flow of fluid comprising the steps of:

• providing a device having a rotor, at least one stator and compression means wherein said rotor has a rotor fluid communication means and a rotor load bearing surface which rotor load bearing surface sealably engages a stationary load bearing surface, said rotor capable of assuming a first position and a second position by rotation;
• and said at least one stator has said stationary load bearing surface having stator fluid communication means, said stationary load bearing surface sealably engaging said rotor load bearing surface and permitting rotation of said rotor with respect to said stator;
• at least one of said rotor bearing surface and said stationary load bearing surface having a diamond like carbon-silica coating;
• and said compression means for holding said at least one stator and rotor with said rotor load bearing surface and stationary load bearing surface sealably engaged, and said diamond-like carbon-silica coating providing a low friction and increased hardness allowing repeated movement between said first and second positions;
• rotating said rotor from one of said first position and said second position to the other position, to control the flow of fluid.