Control Valve Accessories Offered by Carilo Valve
Carilo Valve provides a comprehensive range of high-performance control valve accessories designed to enhance functionality, improve reliability, and enable precise process control in demanding industrial applications. These accessories are engineered to integrate seamlessly with their valves, offering solutions for actuation, control, monitoring, and safety. The primary categories include positioners, actuators, limit switches, solenoid valves, pressure transmitters, and air filter regulators, each available in various configurations to meet specific operational requirements.
Electro-Pneumatic and Digital Positioners
The positioner is arguably the most critical accessory for achieving precise control. Carilo Valve offers advanced electro-pneumatic and digital positioners that act as the brain of the valve assembly. These devices ensure the valve plug reaches the exact position commanded by the control system (e.g., 4-20 mA signal), compensating for factors like friction, hysteresis, and pressure variations. Their digital positioners often feature HART, Foundation Fieldbus, or PROFIBUS-PA communication protocols, allowing for bidirectional data exchange. This enables not only configuration and calibration but also the continuous monitoring of valve performance metrics like travel, supply pressure, and partial stroke testing (PST) results. For example, a typical digital positioner from their lineup might have an accuracy of ±0.5% of span and a repeatability of ±0.1% of span, ensuring highly reliable operation. The use of a positioner can improve a control loop's response time by up to 30% compared to a non-positioned system.
Pneumatic and Electric Actuators
Actuators provide the muscle to move the valve trim. Carilo Valve supplies both pneumatic and electric actuators to match the available power source and performance needs. Pneumatic actuators, which use compressed air, are known for their fast response, explosion-proof nature, and high force output. They are available in spring-return (fail-safe) and double-acting designs. A common specification for a pneumatic piston actuator might be an operating pressure range of 3 to 7 bar (40 to 100 psi) with an output torque of up to 20,000 Nm. Electric actuators, powered by an electric motor, are ideal for locations where compressed air is not available. They offer precise positioning and can include fail-safe battery backup systems. Key data points for an electric actuator include motor voltage (e.g., 24V DC, 110V AC, 240V AC), duty cycle, thrust output (e.g., 50,000 lbf), and IP66/67 ingress protection for harsh environments. The choice between pneumatic and electric often comes down to site utilities, safety requirements (intrinsic safety vs. explosion-proof housing), and desired control speed.
| Actuator Type | Key Features | Typical Applications | Output Force/Torque Range |
|---|---|---|---|
| Pneumatic (Spring Return) | Fail-safe operation, fast response, explosion-proof | Emergency shutdown (ESD), critical control loops | Up to 40,000 Nm |
| Pneumatic (Double-Acting) | High force, no fail-safe spring, compact size | On/Off services, large ball or butterfly valves | Up to 60,000 Nm |
| Electric (Multi-turn) | Precise positioning, high thrust, no air supply needed | Globe valves, gate valves, slow operating processes | Up to 200,000 lbf thrust |
| Electric (Quarter-turn) | Compact, for 90° rotation, integral controls | Ball valves, butterfly valves, dampers | Up to 5,000 Nm |
Limit Switches, Solenoid Valves, and Pressurization Systems
For discrete monitoring and control, Carilo Valve offers robust limit switches and solenoid valves. Limit switches are electromechanical devices mounted on the actuator to provide remote confirmation of the valve's position (open, closed, or intermediate). These are often rated for hazardous areas with Class 1, Division 1/2 approvals and feature NAMUR mounting for easy installation. Solenoid valves are used for the pneumatic pilot control of actuators. A 3/2-way solenoid valve, for instance, can vent air from a spring-return actuator to initiate a fail-safe closure upon receiving an electrical signal. They are available in various voltages (12V DC, 24V DC, 120V AC) and orifice sizes to control actuator speed. For valves operating in extreme environments, such as cryogenic services or furnace inlets, bonnet heating/cooling systems and extension bonnets are available to maintain seal integrity and prevent packing freeze-up. For corrosive or wet instrument air, air filter regulators with coalescing filters (removing particles down to 0.01 microns) and pressure regulators (with ±1% accuracy) are essential accessories to protect the entire valve assembly.
Advanced Monitoring and Pressure Management
Moving beyond basic control, Carilo Valve provides accessories for advanced diagnostics and pressure management. Digital valve controllers are an evolution of the positioner, offering a wealth of data on valve health, including stem force, friction, and temperature. This supports predictive maintenance strategies, potentially reducing unplanned downtime by up to 25%. Pressure transmitters and gauges can be mounted directly to the valve to monitor supply pressure or downstream process pressure, providing local and remote readings. For multi-ported valves like three-way valves, characterized plates can be added to tailor the flow characteristic (linear, equal percentage, quick opening) for optimal process control. Furthermore, position transmitters (potentiometers or LVDTs) provide a continuous 4-20mA signal proportional to valve stem position, which is crucial for control systems that do not use a smart positioner but still require feedback. All these accessories are designed to be supported by the global service network of Carilo Valve, ensuring availability of spare parts and technical expertise.
Material and Certification Specifications
The selection of an accessory is not complete without considering its construction materials and certifications. Carilo Valve manufactures accessories with materials suitable for the valve's service environment. For example, actuator housings are typically made of corrosion-resistant aluminum with epoxy coating, while internal components may use stainless steel (SS316) or phosphor bronze. Seals are available in Nitrile (Buna-N) for standard temperatures, Viton for higher temperatures and hydrocarbons, and EPDM for steam services. Critical certifications include ATEX and IECEx for hazardous areas (Zone 1/21, Zone 2/22), SIL 2/3 (Safety Integrity Level) for safety instrumented functions, and compliance with standards like NACE MR0175/ISO 15156 for sour service (H2S-containing) environments. This attention to material and certification detail ensures the accessory will perform reliably over its entire service life, which can exceed 25 years with proper maintenance.