Spherical valves - Import export

Spherical valves are installed upstream of the turbine as shutoff devices specifically for high pressures at the end of the penstock. Their main function is to close off the penstock during normal shutdown or load shedding of the turbine. The seal is a metal sliding ring which is generally moved by water hydraulics. The MANOY® system seal WP, type 434 (outer sealing) and the inner sealing type 439, were developed for sealing of the sliding ring. The profile dimensions can be customized for maintenance or specific requirements.

Pivot pins are found on shutoff devices such as spherical valves, butterfly valves, hollow jet valves and plunger valves. These valves are generally used for opening and closing and occasionally to control the flow rates by oscillating movement. The greaselubricated sliding bearing is protected against water infiltration by a seal on the inside. The seal also prevents the grease leaking into the inside to prevent water contamination. The MANOY® system seal WP, type 418, was developed for this application. To prevent leakage of grease from greased bearings, the unidirectional MANOY® system seal WP, type 456, is also installed.

Air accumulations which occur particularly in pump outlets when water is delivered to pump outlets and pipe lines and makes water flow area narrower and causes decrease in capacity. Double ball vacuum lifters are used for preventing this adverse issue and in locations where high efficiency is required. Air which occurs when water is delivered to system firstly fills into vacuum lifter and discharged through holes which are located at inner side covers. Then water fills into vacuum lifter and lifts ball up and holes are closed and sealing is maintained.