Dry lubricants are divided into two main classes: laminar soft materials whose low shear allows surfaces to slip over each other and hard materials which run with minimal wear. Ball bearings with dry lubricants are employed for space applications where bearings must run in vacuum and temperature extremes. It provides lubrication for most surfaces, including metal, plastic, wood, leather, fiber, elastomers, and glass.
Dry pipe valve is a dry pipe sprinkler system water-supply control valve that makes possible the installation of sprinkler systems in buildings subject to freezing temperatures. It is designed so that air pressure in the piping system can hold back water pressure at the valve until such time as a sprinkler is activated. Upon such activation the air pressure in the system can decay sufficiently to cause automatic operation of the valve and admission of water into the system. The valve has a 5:1 pressure differential ratio.