Motor actuators for rising stem valves can be powered by air, gas, hydraulic or electric power.
The Fig. 1710 Balancing valve is a non-rising stem design incorporating a parabolic (plug) shaped disc.
Sluice valves are to be of a non-rising stem type and to have solid wedge discs.
"While they are more compact than rising stem valves, the stem threads are always exposed to flowing media, allowing for possible erosion/corrosion. Open/close indication is not provided with this design."
