Here's a method for making DIY servo driven butterfly valves for syngas/air mixing, or other gas flow control needs. The industrial versions of these are usually terribly expensive. Here's a way to make them much less so. This method uses a heavy duty RC servo and common plumbing butterfly valves. You can use the method to make nearly any size servo driven butterfly valve. The files and steps below relate to a 1" valve. The valves are available via McMaster Carr here: http://www.mcmaster.com/#9798k35/=88ksru
Servo valve installed on a Power Pallet (July 2010)
1. Armature
CNC plasma or laser cut armature mounting plate (file: ServoValve3.dxf).
Brake armature as indicated and tack weld corners.
Assure snug fit of valve inside bent tabs.
Paint armature.
2. Servo Lovejoy
Attach double servo-arm included with servo to the first shaft couplers by carefully tapping and installing 2 4-40 machine screws. If done manually, a centering jig can be made with a 3/16" round standoff and 6-32 nut through the servo-arm. Shorten arms by cutting and sanding.
3. Valve Lovejoy
Remove packing from valve. Tap the second flex-coupler to 1/4"-20. Install jam nut at the base of the valve stem. Screw on flex-coupler and tighten set screw. Back jam nut against flex-coupler. We also apply a small amount of Loctite to ensure the parts remain tight.
3. Enclosure
Use a hole saw to drill a hole for the 1" barb. Hole is centered at 1.5" over (centered between) and 1.25" up from bottom holes in enclosure.
4. Assembly
Fit valve into armature and use a zip-tie around the valve and bottom of the armature to hold valve in place.
Slide servo into the armature and install spider between valve and servo.
Install armature into enclosure using two 1/4"-20 bolts and nuts. Screw the conduit locknut on the barb and screw the barb into the valve from the back of the enclosure, tighten the lock nut down while holding the valve from the opposite side.
The resulting valve can be mounted in an enclosure if desired. We usually put them in standard NEMA boxes, like below.
Bill of Materials
Part Description |
# per unit |
Vendor |
Part # |
Servo Valve Armature - 1/16" steel |
1 |
In-house
|
ServoValve3.dxf
|
Shaft Coupler - Flexible Spider Shaft Coupling Hub 3/16" Bore, 5/8" OD
|
2 |
McMaster |
6408K912 |
Buna-N Spider |
1 |
McMaster |
6408K61 |
Jam Nut - 1/4-20 |
1 |
McMaster |
|
Butterfly Valve 1" |
1 |
McMaster |
9798K35 |
NEMA 3R Enclosure 8x6x4 |
1 |
McMaster |
7649K38 |
1" barb |
1 |
McMaster |
5363K43 |
1" hose clamps |
1 |
McMaster |
5416K14 |
1" conduit nuts |
1 |
McMaster |
7513K243 |
Servo HS-755HB |
1 |
Servo City |
33755S |
Servo Extension |
1 |
Servo City |
SE2248S |
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