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Pneumatic actuators with positioners

Pneumatic actuators with positioners

Introduction

What are pneumatic actuators with positioners and how do they work in industry?

Pneumatic actuators with positioners are technologically advanced devices used in industrial automation for precise control of piston movement. In this article, we will explain what these actuators are, how they work, and why they are indispensable in industries such as energy, mining, and metallurgy. Drawing on technical specifications from market leaders like APLISENS (APIS) and Siemens (SIPART PS2), we will discuss their construction, operating principles, and practical applications. They enable piston positioning with an accuracy of tenths of a millimetre, making them an ideal solution where precision and reliability are critical – from controlling valves in power plants to regulating ventilation flaps in mines.

Double-acting pneumatic actuators with positioners are equipped with positioners – either pneumatic or electropneumatic – that control piston movement by comparing a control signal (typically 4-20 mA with the HART protocol) with its actual position. Their design, based, among other things, on magnetic coupling between the piston and the position transmitter, ensures stability even in extreme conditions such as high temperatures, dust, or humidity. This makes them suitable for automating processes like adjusting the tension of conveyor belts or precisely positioning components in steelworks.

Basic operating principles of pneumatic automation systems

The operation of pneumatic actuators relies on compressed air as the working medium. The key components of the system include: a compressor supplying compressed air, a filtration system ensuring the medium’s purity (particles ≤5 µm), an actuator performing mechanical movement, and a positioner that precisely regulates airflow. Modern positioners, such as APIS and SIPART PS2, offer diagnostic functions and auto-calibration, enhancing the reliability and efficiency of industrial processes. Pneumatic automation systems are valued for their simplicity, speed, and ability to operate in challenging conditions, including explosion-hazard zones (ATEX), as confirmed by industry standards like ISO 8573-1.

What is a positioner in pneumatic actuators?

A positioner, also known as a pneumatic or electropneumatic positioner, is an advanced industrial automation device that precisely controls the position of a piston in pneumatic actuators or control valves. Its primary role? Ensuring accurate piston positioning by comparing a control signal – typically an electrical 4-20 mA with the HART protocol – with its actual position, measured using sensors such as potentiometers or non-contact NCS sensors. In this article, we will explain how a positioner works, the types available, and why it is essential in industries ranging from energy to metallurgy. Drawing on technical data from market leaders like APLISENS (APIS) and Siemens (SIPART PS2), we will discuss their specifications and advantages.

Types of positioners: pneumatic vs electropneumatic

Depending on their design, two main types of positioners can be distinguished:

  • Pneumatic positioner: Controlled solely by a pneumatic signal, it is simpler in construction and reliable in basic applications, such as older industrial installations.
  • Electropneumatic positioner: Converts an electrical signal (e.g., 4-20 mA) into a pneumatic one, offering greater precision and advanced features like diagnostics and auto-calibration. Examples? APIS and SIPART PS2, which support remote monitoring and operation in challenging conditions.

Comparison of positioner types – advantages and limitations

Which positioner should you choose? Here’s a brief comparison:

Pneumatic:

  • Advantages: Simplicity, lower cost, resistance to electrical interference.
  • Limitations: Lower precision, lack of advanced diagnostics.

Electropneumatic:

  • Advantages: High accuracy (up to 0.1 mm), diagnostic functions (e.g., leak detection), compatibility with DCS systems.
  • Limitations: Higher cost, requires electrical power.

Modern positioners, such as APIS (with ATEX certification) or SIPART PS2 (with a “Fail Safe” function), are designed for demanding industrial applications. Their technical specifications – such as a temperature range from -40°C to +85°C or an IP65 protection rating – comply with industry standards (e.g., EN 60079-11). This makes them suitable for precise control of valves, dampers, or conveyor belts, even in extreme conditions like dust or humidity.

Applications of pneumatic actuators with positioners in industry

Pneumatic actuators with positioners are versatile devices that revolutionise precise control in industrial automation. Where are they used? From mines to power plants – their ability to accurately regulate piston position makes them indispensable across many sectors. In this section, we will explore how pneumatic actuators with positioners support critical processes in industries such as mining, energy, and metallurgy. Drawing on examples of applications from devices like APIS (APLISENS) and SIPART PS2 (Siemens), we will demonstrate why they are an excellent choice for precise control in challenging conditions.

Mining industry: precise control of dampers and gate

In mines, pneumatic actuators with positioners, such as APIS with ATEX certification, are used for precise control of ventilation dampers and gates in ventilation systems. Why is this important? Accurate airflow regulation ensures worker safety and optimises underground working conditions. Thanks to their resistance to dust and ability to operate in explosion-hazard zones (II 2G Ex ia IIC T5/T6 Gb), these devices guarantee reliability where other solutions might fail.

Energy industry: accuracy in controlling regulating valves

In the energy sector, pneumatic actuators with positioners, such as SIPART PS2, play a crucial role in precisely controlling regulating valves in power plants. They enable stable control of steam, gas, or water flow in boiler and cooling systems, enhancing process efficiency and safety. Features like “Fail Safe” and “Partial Stroke Test” in SIPART PS2 allow for rapid response in emergency situations, minimising the risk of downtime.

Metallurgy industry: control of component positioning in production processes

W hutnictwie precyzyjne ustawienie tłoka siłowników pneumatycznych z ustawnikiem pozycyjnym wspiera kontrolę ruchu elementów linii produkcyjnych. Przykładowo, urządzenia te sterują przesuwaniem form, otwieraniem klap piecowych czy pozycjonowaniem detali – wszystko z dokładnością do 0,1 mm, nawet przy wysokich temperaturach (do +120°C). Ich wytrzymałość na ekstremalne warunki, potwierdzona normami branżowymi (np. ISO 8573-1), czyni je idealnym wyborem dla wymagających procesów hutniczych.

Other applications: from conveyor belts to linear automation

Pneumatic actuators with positioners also find applications beyond the main industries:

  • Transport and logistics: Tension adjustment of conveyor belts in conveyor systems, ensuring smooth processes.
  • Chemical industry: Precise control of valves in installations resistant to aggressive media.
  • Paper industry: Control of paper tension and mechanical movements in production lines.

Thanks to advanced diagnostic features and flexible mounting options (direct or remote), these actuators meet the demands of modern automation.

Construction and operating principle of pneumatic actuators with positioners

How do pneumatic actuators with positioners work, and what makes them so precise in industrial automation? These advanced devices combine compressed air with positioning technology, enabling accurate control of piston position even in extreme conditions. In this section, we will explain their construction and operating principle, drawing on examples of popular models such as APIS (APLISENS) and SIPART PS2 (Siemens). You’ll discover which structural components ensure reliability and why these actuators are chosen for precise control in industries ranging from mines to power plants.

Structural components of a pneumatic actuator with a positioner

Pneumatic actuators with positioners consist of three main modules that work together to ensure precision and stability:

Pneumatic module: the heart of the system

The pneumatic module powers the actuator with compressed air, regulating its flow to precisely position the piston. Key features? The working medium (e.g., compressed air or nitrogen in SIPART PS2), filtration compliant with ISO 8573-1 (particles ≤5 µm, recommended ≤1.5 µm for APIS), and an operating pressure range of 1.4 to 8 bar. Minimal air consumption (e.g., 0.035 kg/h in APIS) reduces operating costs, making it an efficient solution for industry.

Electrical module: precise control

The electrical module converts a control signal – typically 4-20 mA with the HART protocol – into a pneumatic signal. With a power supply of 10-36 V DC and resistance to power interruptions (e.g., in SIPART PS2), it ensures stability in harsh conditions. Options such as analogue outputs or DIO (Digital I/O) modules in SIPART PS2 enable remote monitoring of piston position – ideal for DCS systems.

Positioning module: precision in detail

The key to accuracy? Position transmitters, such as potentiometers or non-contact NCS sensors (in SIPART PS2). Combined with magnetic coupling, they measure piston position with an accuracy of 0.1 mm. The separated sensor mounting option (e.g., in APIS) allows operation in extreme temperatures or vibrations, proving effective in steelworks and mines.

The role of magnetic coupling and resistance to external conditions

What makes these actuators reliable in dusty environments or at +120°C? The magnetic coupling between the piston and the transmitter eliminates mechanical wear and is insensitive to dust, moisture, or aggressive media. Standards such as IP65 (protection against dust and water) confirm their durability. In APIS, the temperature range extends from -40°C to +85°C, making them ideal for ATEX zones, such as in the chemical industry.

Mounting options for the positioner: flexibility in practice

How to install a positioner? There are two options:

  • Direct mounting: A compact solution on the actuator, popular in APIS and SIPART PS2, suitable for stable conditions.
  • Remote mounting: The sensor on the actuator and the positioner in a safe location – perfect for extreme environments like high temperatures or vibrations.

How does it work? Operating principle in brief

A pneumatic actuator with a positioner uses compressed air to move the piston, while the positioner regulates airflow based on an electrical signal. Thanks to auto-calibration (e.g., in APIS) and diagnostic functions (e.g., “Valve Signature” in SIPART PS2), the device adapts to requirements and monitors the system’s condition. The result? Precision and reliability in controlling valves, dampers, or conveyor belts.

Technical characteristics of pneumatic actuators with positioners – what you need to know

What technical parameters make pneumatic actuators with positioners so valued in industrial automation? Their precision, versatility, and reliability stem from an advanced design that performs well in a wide range of applications – from small valves to large gates. In this section, we will examine the key features of these devices, based on specifications from market leaders like APIS (APLISENS) and SIPART PS2 (Siemens). You’ll learn how to select the right actuator for your needs and why technical parameters are crucial for the efficiency of industrial processes.

Range of actuator diameters: from D20 to D320 – flexibility in selection

Pneumatic actuators with positioners offer a wide range of piston diameters – from compact D20 mm to robust D320 mm. Why is this important? It allows the device to be tailored to specific tasks:

  • Small diameters (D20-D50 mm): Ideal for precise control of small valves in process automation.
  • Medium diameters (D63-D125 mm, e.g., D63x80 cylinder, order number 18.3712): A versatile solution for flow regulation in industrial installations.
  • Large diameters (D160-D320 mm, e.g., D250x200 actuator with BTL linear transducer, order number 18.4518): Used in energy or mining industries to control large gates and valves.

This enables you to select a pneumatic actuator perfectly suited to the force requirements and mounting space of your application.

Range of strokes: from 10 mm to 3000 mm – from precision to long movements

These actuators support strokes ranging from short 10 mm to an impressive 3000 mm, making them versatile in automation. How does this work in practice?

  • Short strokes (10-100 mm, e.g., ISO D250x40 BSPT actuator, order number: 18.3652): Precise control of dampers or regulating valves, e.g., in SIPART PS2.
  • Medium strokes (100-1000 mm, e.g., ISO D125x320 actuator with BTL linear transducer and APIS positioner, order number: 18.4612): Tension adjustment of conveyor belts or technological movements.
  • Long strokes (1000-3000 mm): Transport systems and production lines in steelworks or mines.

This range allows for flexible application – from subtle movements to large-scale displacements.

Operating temperature range: from -20°C to +120°C – reliability in all conditions

Pneumatic actuators with positioners operate in temperatures from -20°C to +120°C, and in special versions (e.g., APIS) even from -40°C to +85°C. What does this mean? They are ready for:

  • Low temperatures: Special seals ensure tightness in freezing conditions, such as in cold storage warehouses.
  • High temperatures: Heat-resistant materials perform reliably in steelworks or power plants.

Standards like IP65 confirm their durability, making them a reliable choice in extreme environments.

Piston position adjustment accuracy: up to 0.1 mm – precision at the highest level

Thanks to electropneumatic positioners and technologies like NCS (in SIPART PS2) or magnetic sensors (in APIS), these actuators achieve an adjustment accuracy of tenths of a millimetre. This is crucial in applications requiring consistent positioning, such as valve control in the energy sector or component positioning in metallurgy. High precision enhances the quality and efficiency of production processes.

Requirements for medium quality: compressed air ≤5 µm – durability and efficienc

To ensure faultless operation, the working medium – typically compressed air – must meet the ISO 8573-1 standard (class 3, particles ≤5 µm, recommended ≤1.5 µm for APIS). How can this be achieved? Use filters, pressure regulators, and dryers. Clean air extends the device’s lifespan and reduces maintenance costs, as confirmed by manufacturers like APLISENS and Siemens.

Positioners exemplified by APIS and SIPART PS2 – what do they offer in industrial automation?

Which positioners stand out in the precise control of pneumatic actuators? APIS from APLISENS and SIPART PS2 from Siemens are market leaders, combining advanced technology with reliability. In this section, we will examine their technical specifications and explain why they are chosen in demanding industries such as energy, chemicals, and mining. Based on manufacturer data, we will discuss their features – from auto-calibration to operation in ATEX zones – so you can assess which model best suits your application.

Technical specifications of the APIS positioner – precision and safety

The APIS electropneumatic positioner is a versatile solution for single- and double-acting actuators, both linear and rotary. What sets it apart?

Auto-tuning and built-in diagnostics

Thanks to its auto-calibration function, APIS automatically adapts to the actuator, ensuring precise regulation without overshooting. Built-in diagnostics – such as piston position monitoring or error analysis via HART – allow for real-time assessment of the system’s condition. This makes it an ideal tool for preventive maintenance, reducing downtime costs.

Use in hazardous areas (ATEX)

The ATEX certification (II 2G Ex ia IIC T5/T6 Gb) ensures APIS is safe for use in explosive zones, such as in the chemical or gas industries. Its resistance to temperatures from -40°C to +85°C and IP65 protection rating confirm its reliability in harsh conditions.

Optional remote sensor mounting

The position sensor can be mounted separately from the positioner, which is ideal for extreme environments – such as high temperatures or vibrations. This flexibility is something you’ll appreciate in mines or steelworks.

Technical specifications of the SIPART PS2 positioner – advancement and flexibility

SIPART PS2 is one of the most advanced electropneumatic positioners, valued for its diagnostic capabilities and versatility. What does it offer?

Diagnostic and safety functions (“Fail Safe”, “Fail in Place”)

SIPART PS2 ensures safety with modes like “Fail Safe” (moving to a safe position during a failure) and “Fail in Place” (maintaining position). Tests such as “Partial Stroke Test” or “Valve Signature” monitor valve condition, meeting SIL 2 standards. This is critical in the energy sector, where process stability is a priority.

Compatibility with various gases (nitrogen, carbon dioxide)

In addition to compressed air, SIPART PS2 supports gases like nitrogen or CO₂, expanding its use in the chemical or gas industries. Standards such as ISO 8573-1 ensure compatibility with high-quality working media.

Separated position detection mounting

Similar to APIS, SIPART PS2 allows the sensor to be separated from the positioner, which is ideal in harsh conditions – such as radiation or aggressive media. This solution enhances durability and reliability.

APIS vs SIPART PS2 – which positioner to choose?

Feature APIS (APLISENS) SIPART PS2 (Siemens)
Positioner type Electropneumatic Electropneumatic
Control signal 4-20 mA with HART 4-20 mA with HART
Adjustment precision Up to 0.1 mm Up to 0.1 mm
Auto-calibration Yes, automatic adjustment Yes, automatic adjustment
Diagnostics Built-in (position monitoring, HART) Advanced ("Partial Stroke Test", "Valve Signature")
Safety features No specific "Fail Safe" modes "Fail Safe", "Fail in Place", SIL 2
Working medium Compressed air (ISO 8573-1, ≤1.5 µm recommended) Compressed air, nitrogen, CO₂ (ISO 8573-1)
Operating temperature range -40°C to +85°C -20°C to +120°C (depending on version)
ATEX certification Yes (II 2G Ex ia IIC T5/T6 Gb) Optional (in special versions)
Protection rating IP65 IP65
Position sensor mounting Direct or remote Direct or remote
Main application Mines, chemical industry, ATEX zones Energy sector, chemical industry, diagnostics
Air consumption Minimal (e.g., 0.035 kg/h) Low, configuration-dependent
Gas flexibility Limited to compressed air Supports various gases (e.g., nitrogen, CO₂)
Cost Lower, simpler design Higher, advanced features
Best suited for Simplicity and safety in harsh conditions Flexibility and advanced control

Both devices offer precision and diagnostics, but they differ in focus: APIS excels in ATEX zones and ease of use, while SIPART PS2 stands out for gas flexibility and advanced safety features. The choice depends on your needs – for example, APIS is ideal for mines, while SIPART PS2 suits power plants. Want to learn more about their parameters and applications? Check the following sections to find the perfect solution for your industry!

Installation and maintenance tips for actuators with positioners – how to ensure their reliability?

How do you properly install and maintain pneumatic actuators with positioners to ensure they operate faultlessly for years? Proper installation and maintenance are key to maximising their precision and durability in industrial automation. In this section, we will provide practical recommendations based on guidelines from manufacturers APIS (APLISENS) and SIPART PS2 (Siemens), with a special focus on safety in ATEX zones. You’ll learn how to avoid common mistakes and optimise the performance of these devices in your application – whether in a mine or a power plant

Manufacturer’s recommendations for installation and commissioning – step by step

Proper installation of an actuator with a positioner is the foundation of its efficiency. Here are the key tips:

  • Location selection: Direct mounting on the actuator (e.g., in SIPART PS2) works well in stable conditions, while remote mounting (e.g., in APIS) is suited for extreme environments like high temperatures.
  • Working medium: Use compressed air compliant with ISO 8573-1 (particles ≤5 µm, recommended ≤1.5 µm for APIS), employing filters and dryers to extend lifespan.
  • Pipe installation: Short, leak-proof pneumatic pipes and properly connected electrical cables (with glands) minimise the risk of failure.
  • Calibration: Utilise auto-tuning (available in APIS and SIPART PS2) to adjust the positioner to the actuator – this ensures precision.
  • Leak test: Before commissioning, check the pneumatic system to avoid leaks and ensure stability.

These steps, aligned with manufacturers’ documentation, form the basis for reliable operation.

Safety guidelines – especially for ATEX versions

In explosion-hazard zones (e.g., the chemical industry), safety is a priority. How can it be ensured?

  • Compliance with standards: Installation in ATEX versions (e.g., II 2G Ex ia IIC T5/T6 Gb in APIS) must meet EN 60079-11 – use certified cables and glands.
  • Earthing: Protect the housing against electrostatic discharges, which is critical in explosive zones.
  • Service: Repairs should only be carried out by authorised personnel – unauthorised interference compromises safety and warranty.

These principles, based on guidelines from APLISENS and Siemens, safeguard both equipment and personnel.

Maintenance and service procedures – how to extend lifespan?

Regular maintenance is the key to keeping actuators in top condition. What should you do?

  • Leak checks: Inspect pipes and valves every few months to detect leaks – this extends the lifespan of the pneumatics.
  • Position transmitter: Verify the sensor’s accuracy (e.g., NCS in SIPART PS2) and recalibrate it if deviations are noticed.
  • Diagnostics: Use built-in tools like “Partial Stroke Test” (SIPART PS2) or HART analysis (APIS) to monitor technical condition.
  • Parts replacement: Regularly replace seals and air filters according to the manufacturer’s schedule – a cost-effective way to prevent failures.
  • Documentation: Record all service activities to simplify tracking history and planning future repairs.

These practices, backed by manufacturers’ expertise, reduce costs and enhance reliability.

How to optimise the operation of actuators with positioners?

Proper installation and regular maintenance are the keys to success. Thanks to these, actuators like APIS and SIPART PS2 will deliver precision and stability across every industry – from logistics to energy.

FAQ – Frequently Asked Questions about pneumatic actuators with positioners

Do you have questions about pneumatic actuators with positioners? In this section, you’ll find answers to the most common queries, helping you better understand their operation, selection, and use in industrial automation. From the differences between positioner types to practical tips – here’s everything you need to know!

What’s the difference between a pneumatic and an electropneumatic positioner?

A pneumatic positioner operates solely on a pneumatic signal, making it simpler and cheaper but less precise, ideal for older installations. In contrast, an electropneumatic positioner, like APIS or SIPART PS2, converts an electrical signal (e.g., 4-20 mA with HART) into a pneumatic one, offering accuracy up to 0.1 mm and advanced features such as diagnostics and auto-calibration. The choice depends on your needs – electropneumatic is best where precision and monitoring matter.

Which pneumatic actuators with positioners should I choose for mining?

For mines, we recommend actuators with positioners in ATEX versions, such as APIS from APLISENS. Their certification (II 2G Ex ia IIC T5/T6 Gb) ensures safety in explosive zones, while resistance to dust and temperatures from -40°C to +85°C guarantees reliability. They’re perfect for precisely controlling ventilation dampers and gates, crucial for underground ventilation.

Why use actuators with positioners in industry?

Actuators with positioners offer precise adjustment (up to 0.1 mm), resilience in extreme conditions (e.g., +120°C, IP65), and diagnostics (e.g., “Partial Stroke Test” in SIPART PS2), improving efficiency and cutting maintenance costs. They’re versatile – from energy to metallurgy – and essential where process stability is a priority.

FAQ – Frequently Asked Questions about pneumatic actuators with positioners

How do I select a pneumatic actuator with a positioner for my application?

Selection depends on several parameters: diameter (D20-D320 mm), stroke (10-3000 mm), operating temperature (-20°C to +120°C), and precision requirements. For example, choose smaller diameters (D20-D50 mm) for small valves, or larger ones (D160-D320 mm) for big gates in energy applications. Also, consider the working medium (e.g., nitrogen in SIPART PS2) and environmental conditions – opt for APIS in ATEX zones.

What does magnetic coupling provide in actuators with positioners?

Magnetic coupling connects the piston to the position transmitter without mechanical contact, eliminating wear and boosting reliability. It’s unaffected by dust, moisture, or temperatures up to +120°C, ensuring actuators like APIS and SIPART PS2 perform precisely in tough conditions, such as steelworks or mines.

What are the compressed air requirements for pneumatic actuators?

Compressed air must meet ISO 8573-1 (class 3, particles ≤5 µm, recommended ≤1.5 µm for APIS) to ensure actuator and positioner durability. Use filters, dryers, and pressure regulators – clean air reduces failure risks and operating costs, as confirmed by manufacturers like Siemens and APLISENS.

APIS or SIPART PS2 – which positioner is better?

It depends on the application. APIS excels in ATEX zones and ease of use, making it ideal for mines or the chemical industry. SIPART PS2 offers advanced safety features (“Fail Safe”) and gas compatibility (e.g., nitrogen), making it a leader in energy applications. Compare your needs – precision, diagnostics, and working conditions will decide.

Summary

Pneumatic actuators with positioners are a reliable and precise solution in industrial automation, ideal for industries such as energy, mining, and metallurgy. In this article, we covered their construction, operating principles, applications, and advantages – from adjustment accuracy (up to 0.1 mm) to resilience in extreme conditions (ATEX, IP65). Using APIS and SIPART PS2 as examples, we demonstrated how to choose the right model, while practical installation and maintenance tips will help you maximise their efficiency.

Contact us!

Have questions or need assistance in selecting pneumatic actuators with positioners? Our experts at CPP PREMA are ready to advise and offer the best solutions for your application. Email us at export@cpp-prema.pl– together, we’ll find the perfect actuator for your business!