Valve actuation can be broken down as follows:

Manual operation: It is done, for example, by a button, a pedal or a lever.
Mechanical actuation: It is carried out, for example, by a roller button, a spring or a mechanical lock.
Pneumatic actuation: It is by pressure, differential pressure or low pressure.
Electrical actuation: This is usually done by an electromagnet

Actuation of way valves according ISO 1219

remark:  ISO = Abbreviation for International Standard Organisation

Link:           http://www.iso.org/iso/home.html