Actuator for butterfly valves
View Patent ↗An actuator for a butterfly valve, having a gearbox, an actuator stem and a handle. The actuator stem is formed as a single piece, comprising a position indicator, seal disc, worm gear, and stem shaft with splines for fitting into the valve. The handle is also formed as a single piece, comprising the wheel or knob, shaft, and worm for operating the worm gear. By forming the gearbox as a single piece as well, the entire actuator can be made as three major pieces. Optionally, the gearbox can be formed with cylindrical fittings which press-fit over pins on the valve, replacing the conventional mounting bracket.
1. An actuator for butterfly valves, comprising:
a) a gearbox having an upper surface, a lower surface, a first side surface and an opposing second side surface, and a hollow interior;
b) a stem passing through a hole in the upper surface of the gearbox, through the hollow interior, and through a hole in the lower surface of the gearbox, comprising, arranged axially along the stem from an upper end to a lower end:
a seal disc for sealing the hole in the upper surface of the gearbox;
a worm assembly with a worm gear; and
a stem shaft having a lower end for inserting into and actuating the valve;
the stem being integrally formed as a single piece,
c) a handle passing through a hole in the first side surface of the gearbox, through the hollow interior, and through a hole in the second side surface of the gearbox, comprising, arranged axially along the stem from a first end to a second end:
a knob;
an outer shaft portion;
a seal disc;
an intermediate portion;
a worm; and
an end portion;
the handle being integrally formed as a single piece; and
d) a valve attachment on the lower surface of the gearbox.
2. The actuator of claim 1 , in which the stem is formed by investment casting.
3. The actuator of claim 1 , in which the handle is formed by investment casting.
4. The actuator of claim 1 , in which the gearbox is formed by investment casting.
5. The actuator of claim 1 in which the stem further comprises a valve position indicator on the upper end of the stem.
6. The actuator of claim 1 in which the lower end of the stem shaft comprises a spline for press-fitting into a bore in a valve element.
7. The actuator of claim 1 in which the end portion of the handle has a driver slot.
8. The actuator of claim 1 in which the valve attachment comprises a bracket held to the lower surface of the gearbox by fasteners.
9. The actuator of claim 1 in which the valve attachment comprises a plurality of posts formed on the lower surface of the gearbox, each post having a central recess for receiving a pin.