RTO Rotary Valve Drive Upgrade: Pneumatic to Electric

February 28, 2022


Pneumatic driven rotary valves on regenerative thermal oxidizers (RTO) have been proven over the past 20+ years, but they do cause significant wear. Pneumatic driven rotary valves also require diligent maintenance and inspections to avoid both nuisance and long-term maintenance shutdowns. The wear is due to the violence of stopping the large-mass valve rotor at the end of travel. Rack and pinion designs work well for these rotary designs, but the cushions at end of travel wear out. If not properly maintained, this leads to other more serious part failures and RTO shutdowns. Pneumatic valve drives use pneumatic air cylinders and solenoids to drive the valve. There are also the typical problems with utilizing pneumatics in RTOs located outdoors due to the risk of moisture/ice forming in the air lines during cold/freezing weather.

This 25,000 scfm capacity Durr Reeco RL RTO had a drive air cylinder and a pinning air cylinder each with its own solenoid actuating valve. These parts are not always readily available which puts the RTO at risk of extended downtime and production schedule upsets.

ORIGINAL DRIVE: Pneumatic Drive Cylinder + Position Locking Cylinder

(RTO valve removed/not shown)




Kono Kogs was chosen to retrofit this electric valve drive upgrade to address the recurring issues experienced with the pneumatic valve drive design. An electric driven rotary switching valve was designed, fabricated and installed in this regenerative thermal oxidizer (RTO). The new electric rotary valve drive included a new rack, a gear box, and variable speed drive, and PLC control logic.

Electric Valve Drive Upgrade- Valve Removed/Stripped Down Main Skid

Electric Valve Drive Upgrade- Partially Re-Assembled

Electric Valve Drive Upgrade- Nearing Completion

Electric Valve Drive Upgrade- Technician Tuning

Electric Valve Drive Upgrade- Valve In Place

Electric Valve Drive Upgrade- Tuned and Operational


The electric valve drive on this RTO and many others have been field proven over thousands of operating hours. If you have wear issues on your current rotary valve drive or freezing pneumatic lines during winter weather, give us a call for a retrofit quote. We have now retrofit this valve upgrade on several Durr-Reeco RL RTOS and MEGTEC Clean Switch RTOs.

See more examples of our custom design and fabrication work.

Equipment / Services provided by Kono Kogs, Inc.
  • Remove pneumatic valve drive
  • Design, fabricate & install electric drive assembly
  • Update PLC controls/Logic for drive control addition
  • Equipment restart

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  • This field is for validation purposes and should be left unchanged.

About Kono Kogs

Kono Kogs has been refurbishing used thermal oxidizers for over 25 years with over 350 installations in nearly every state in the USA and around the world. We offer full refurbishing of quality-built thermal oxidizers and stand behind them with warranties that match new equipment OEM warranties.