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Actuated Butterfly Valve — Complete Automation for Every Material, Diameter, and Control System
The butterfly valve is the most economically efficient isolation and control solution for medium and large diameters, and the actuator is the component that makes it an active element of your control system — capable of responding in seconds to electrical or pneumatic signals, integrable with PLCs, DCS, SCADA, and building management systems, and configurable with the correct fail-safe position for each process. Cematic supplies both as an integrated assembly: a valve selected for your fluid, an actuator sized for the required torque with a verified safety factor, and control accessories installed and tested in our workshop before shipment.
The first decision when automating a butterfly valve is the type of actuator: pneumatic when a compressed air network is available and maximum response speed is required, or electric when there is no pneumatic infrastructure or when proportional modulating control or direct digital communication without an additional positioner is needed. The second decision is the fail-safe mode: normally closed (NC), normally open (NO), or fail-last. Cematic advises on both decisions free of charge based on your application data.
The two actuator families — pneumatic vs. electric
Pneumatic Actuator — Speed, Reliability, and Spring Fail-Safe
The pneumatic rack and pinion actuator converts compressed air pressure (4–8 bar) into 90° rotational motion to operate the butterfly disc. It is the most in-demand actuator in the Mexican industry for butterfly valves for three specific reasons:
- Speed: Operates the butterfly from fully closed to fully open in 1 to 5 seconds — adjustable with speed regulators to prevent water hammer in water systems or synchronize with process sequences.
- Mechanical Spring Fail-Safe: The single-acting NC or NO takes the valve to its predefined position by spring force in case of any failure of air supply or electrical signal — no batteries, no capacitors, no electronic components that can degrade. The reliability of a mechanical spring is superior to any electrical fail-safe system.
- Millions of Cycles: Without an electric motor that can overheat, the pneumatic actuator operates continuous high-frequency cycles with no limitation on cycles per hour.
Requires: Dry compressed air network (4–8 bar) available at the installation point.
👉 See full range: Butterfly Valves with Pneumatic Actuator →
Electric Actuator — No Pneumatic Network, Modulating, and Digital Communication
The electric actuator converts electrical energy (24 VDC, 110 VAC, or 220 VAC) into 90° rotational motion via a motor and gear reducer. It is the solution when the installation point does not have a compressed air network or when the process requires:
- Proportional Modulating Control: 4–20 mA input signal to position the butterfly at any angle between 0° and 90° with position feedback — without an additional positioner.
- Direct Digital Communication: Native Modbus RTU or BACnet protocol for integration with SCADA, DCS, or building management systems without additional signal converters.
- Remote Installation Without Pneumatic Infrastructure: Only an electrical cable to the control point — no air piping, no local compressor.
- Power from Solar Panels or Batteries: 24 VDC models operate directly from low-voltage sources for installations in remote areas or solar irrigation systems.
Operating Time: 15 to 120 seconds for full travel (0°–90°) — slower than pneumatic but sufficient for most process applications.
👉 See full range: Butterfly Valves with Electric Actuator →
Fail-safe modes — the most critical decision
The fail-safe mode defines the valve's behavior in the event of a power supply failure (compressed air or electricity) or control system failure. It is the first technical question to answer when specifying any automated valve:
| Fail-Safe Mode | Behavior on Failure | Actuator | Typical Application |
|---|---|---|---|
| Normally Closed (NC / Fail-Close) | Valve CLOSES by spring upon power loss | Single-acting pneumatic NC | Dosing of hazardous reagents, feed to reactors, ESD systems |
| Normally Open (NO / Fail-Open) | Valve OPENS by spring upon power loss | Single-acting pneumatic NO | Cooling systems, lubrication, emergency ventilation |
| Fail-Last | Valve MAINTAINS its last position upon power loss | Double-acting pneumatic or electric | Systems where the last position is the correct safe condition — most general process applications |
| Fail-Close or Fail-Open with battery (electric) | Battery or capacitor moves valve to predefined position in <5 sec | Electric with battery backup | Installations without pneumatic network where defined fail-safe is required |
ON/OFF Control vs. Modulating Control
ON/OFF Control — The Most Demanded Configuration
The valve operates only between fully closed (0°) and fully open (90°) positions. The actuator receives a digital signal from the PLC — dry contact, 24 VDC, or 110/220 VAC — and completes the travel to the mechanical stop. This is the correct mode for:
- Tank filling and emptying sequences
- Automatic network sectioning
- Filter backwash systems
- Emergency Shut-Down (ESD) valves
- Any application where only "flow" or "no flow" of fluid is needed
Pneumatic actuators and most electric actuators operate in ON/OFF mode as standard — without additional accessories.
Modulating Control — For Proportional Flow Regulation
The valve can be positioned at any angle between 0° and 90° proportionally to the PID controller's analog signal (4–20 mA). At 4 mA, the valve is closed; at 20 mA, fully open; at 12 mA, it is at 50% opening. This allows controlling the flow passing through the line in response to a process variable (temperature, level, pressure, or flow). Requires:
- Pneumatic actuator + electropneumatic positioner: The positioner receives the 4–20 mA signal from the controller and adjusts the air pressure to the actuator to precisely position the disc. See Cematic positioners →
- Modulating electric actuator: Electric models with a 4–20 mA input signal incorporate modulating control natively — without an additional positioner. The 4–20 mA position feedback confirms the actual position to the controller. See Cematic electric actuators →
Note on the butterfly as a control valve: The flow characteristic of the concentric butterfly is "quick opening" — the flow increases rapidly in the first degrees of opening and stabilizes in intermediate positions. For precise modulating control throughout the range (0–100%), the double offset high-performance butterfly offers better linearity. For high-precision flow control with greater rangeability, the V-port ball valve or globe valve are technically superior. The concentric butterfly with modulating control is suitable for moderate regulation applications, especially in large diameters where the cost of an equivalent globe valve is prohibitive.
The Cematic package — valve + actuator assembled and tested
The difference between buying the valve and actuator separately and acquiring the Cematic assembly is not just convenience — it is technical reliability from the first operating cycle:
- ✅ Verified technical selection: Calculation of valve operating torque for process diameter and pressure, actuator sizing with correct safety factor (minimum 1.25×), verification of compatible ISO 5211 interface between valve and actuator
- ✅ Professional assembly: Correct alignment of the ISO 5211 coupling with verified bolt torque, installation and connection of the solenoid on the NAMUR port without intermediate piping, installation of limit switch box and adjustment of coupling cam
- ✅ Complete functional test before shipment: Full opening and closing cycles, verification of valve seat tightness, verification of limit switch signals (LS1 open, LS2 closed), adjustment of speed regulators according to application requirements
- ✅ Technical documentation: Assembly datasheet, functional test certificate, electrical connection diagrams for solenoid and limit switches, IOM manual
- ✅ Free integration advice: Guidance for connecting the assembly to the customer's PLC or control panel — identification of terminals, feedback signals, and control logic configuration
Valve materials available in the range with actuator
- Cast iron with EPDM, NBR or Viton: For water, HVAC, general industrial processes, oils and hydrocarbons. The lowest cost option for large diameters. DN50 to DN1200. See →
- Stainless steel SS316 with EPDM or PTFE: For seawater, saline solutions, moderate chemicals, purified water and food distribution processes. DN50 to DN600. See →
- Corrosion-resistant with PTFE liner: For diluted acids, alkalis, hypochlorite, aggressive saline solutions and moderately corrosive fluids in large diameters. DN50 to DN400. See →
- High Performance double and triple offset: For high pressure (ANSI 300–600), high temperature, process vapors and frequent cycles with metallic seat. DN50 to DN1200. See →
- Hygienic SS316L clamp or weldable with EPDM or FDA silicone: For food, beverage and pharmaceutical industries with direct product contact. DN25 to DN150. See →
- PVC with EPDM: For water, agricultural irrigation, swimming pools and processes where metal is not an option. 24 VDC electric or pneumatic actuator. DN50 to DN300. See →
- Lug with EPDM, NBR or Viton: For end of line and points where downstream section needs to be disassembled under pressure. DN50 to DN600. See →
Quick selection guide — pneumatic vs. electric actuator
| If your installation has… | Recommended actuator |
|---|---|
| Compressed air network available at the installation point | ✅ Pneumatic — faster, more economical, spring fail-safe |
| No compressed air network — only electrical wiring | ✅ Electric — the only viable option |
| Simple ON/OFF control from PLC | ✅ Pneumatic or electric — both suitable, pneumatic is faster |
| Native 4–20 mA modulating control (without positioner) | ✅ Modulating electric — includes 4–20 mA control from factory |
| Modulating control with existing pneumatic actuator | ✅ Pneumatic + electropneumatic positioner |
| Direct Modbus RTU communication to SCADA | ✅ Electric with Modbus — no additional converters |
| BACnet communication for building management system (BMS) | ✅ Electric with BACnet — standard in HVAC |
| Very frequent cycles (>30 per hour) | ✅ Pneumatic — no cycle limitation due to motor temperature |
| ATEX Zone 1 classified area (flammable gases or vapors) | ✅ Pneumatic + ATEX solenoid — more economical than full ATEX electric |
| Power from solar panel or battery (24 VDC) | ✅ 24 VDC electric — compatible with solar and battery systems |
| Mandatory defined fail-safe (NC or NO) | ✅ Single-acting pneumatic — mechanical spring without electronic dependence |
Industries and applications
- Potable water and wastewater: Remote control of sectioning in PTAP and PTAR, automatic backwash sequences, integration with SCADA for operating agencies. Cast iron butterfly + electric actuator with Modbus for municipal plants without pneumatic infrastructure.
- HVAC and building management: Zone valves in chilled water and hot water circuits, electric actuator with BACnet or Modbus for BMS integration. The absolute standard in the sector — the butterfly is more economical than the ball in these diameters and the electric does not require a compressor in buildings.
- Chemical and petrochemical industry: Pneumatic actuator with ATEX solenoid for classified areas, single-acting NC for ESD systems, positioner in flow control loops. Corrosion-resistant butterfly for aggressive fluids.
- Food and beverage industry: Pneumatic actuator for high-speed automated CIP sequences, hygienic SS316L butterfly for product lines, cast iron butterfly for water distribution and large diameter CIP.
- Mining: 24 VDC electric actuator with Modbus for control from central SCADA in remote locations without pneumatic infrastructure. Cast iron butterfly for process water and corrosion-resistant butterfly for reagents.
- Power generation: High-performance butterfly with large torque pneumatic actuator for process steam, modulating control with positioner for temperature loops in heat exchangers.
- Agricultural irrigation: 24 VDC electric actuator for irrigation sectors integrated with irrigation controllers, PVC or cast iron butterfly depending on diameter and water quality.
- Pulp and paper: Pneumatic actuator for bleaching and CIP sequences in large diameter lines, high-performance butterfly for high-temperature process steam.
Why choose Cematic for your actuated butterfly valves?
We cover the entire range of butterfly materials — cast iron, SS316, corrosion-resistant, high performance, hygienic, PVC, and Lug — in all diameters demanded by the Mexican industry, with pneumatic and electric actuators in the most frequent voltages and fail-safe configurations. We assemble and test in our workshop. We correctly size the actuator with verified torque calculation. We advise on the decision between pneumatic and electric, between ON/OFF and modulating, and between NC, NO, and fail-last. Stock in Mexico City for the most common combinations. Technical quotes on the same business day. Shipping nationwide. Contact us via WhatsApp or at ventas@cematic.com.