Electric actuator for controlling ball valve
Automating the control of ball valves (BV) in engineering systems is designed for water supply, ventilation, air conditioning and heating systems. An electric actuator (EA) streamlines the process of automation of engineering systems by saving money and time. The EA with a coupling device is fastened to the BV stem. The coupling device comprises an engagement adapter with projections, an adapter washer and a securing member. The reduction gear main shaft is provided with a through hole for receiving the BV stem and the securing member, and a seat provided on the side of the EA and BV stem joint. The adapter washer is placed in the main shaft seat and the engagement adapter is joined permanently with the EA case and engages the BV body with projections.
1. An electric actuator (EA) for controlling a ball valve (BV), comprising:
an electric motor, comprising a gear and a shaft;
a set of intermediate gears and a release gear connected to the electric motor;
a reduction gear comprising a main shaft and a fitted main gear, the reduction gear installed inside an EA case, the main shaft having a through hole and a seat having a shape; and
a coupling device to fasten the EA on a BV stem having a thread, wherein the coupling device comprises:
an adapter washer having a shape matching the shape of the seat in the main shaft of the reduction gear, the adapter washer placed in said seat and resting against lands on the BV stem;
an engagement adapter with projections, the engagement adapter rigidly fastened on the EA case to engage a BV body with the projections;
and
a securing member to secure the EA on the BV stem, when the EA is mounted on the BV stem via the through hole in the main shaft of the reduction gear,
wherein the securing member is one of a retaining nut, or a retaining nut and a retaining screw, wherein the retaining nut has a thread corresponding to the thread of the BV stem.
2. The EA of claim 1 , wherein the securing member is the retaining nut, when the BV stem has an external screw thread.
3. The EA of claim 1 , wherein the securing member comprises the retaining nut and the retaining screw, when the BV stem has an internal screw thread.
4. The EA of claim 1 , wherein the main shaft has grooves to receive a manual opening handle.
5. The EA of claim 1 , wherein the EA comprises a limit switch actuating pin to limit the extreme positions of an EA angle of rotation.
6. The EA of claim 5 , wherein the limit switch actuating pin passes through a hole in an upper plate of the EA and is attached to the main gear fastened on the main shaft.
7. The EA of claim 1 , wherein the EA is operated in an automatic mode, the automatic mode comprising transmitting a torque from the shaft of the electric motor via the electric motor gear and through the set of the intermediate gears and the release gear to the main gear and the main shaft, wherein the main shaft is rigidly joined via the adapter washer and secured with the retaining member to the BV stem, thus transmitting the torque to the BV stem to open or close the BV.
8. The EA of claim 7 , wherein the rotation of the EA case relative to the BV is prevented by the engagement adapter, the EA is secured in extreme position with the help of a limit switch actuating pin, wherein the limit switch actuating pin depresses the limit switches to break the electric circuit and prohibit further electric motor rotation in a given direction.
9. The EA of claim 1 , wherein the EA is operated in a manual mode, the EA comprising a release button which acts on the release gear to disengage the release gear from the set of the intermediate gears, thus disengaging the main shaft from the electric motor shaft, and a manual opening handle is used to open or close the BV.