There are three distinct phases involved in removing or displacing water from another liquid.  The first is particulate filtration.  Many refer to this stage as prefiltration.  During this phase, the goal is to remove as much particulate from a liquid as possible before it enters into the next portion of the process.  During the second phase, coalescing, the liquid enters a coalescer where we develop small droplets of water where it then combines into larger droplets of water, making it easier to remove.  During the third stage, separation, we’re aiming to completely separate the water from the rest of the liquid.  Essentially, the separator will act as a screen and repel any water droplets that are still around the stream.  However, the only way to ensure that this final stage does its job is to be confident that stages one and two are done properly. Part two (coalescing) is becoming more of an essential step in more and more industries, especially those that involve fuel and oil.

For coalescing to have the desired impact, it must be handled properly.  This means walking through the process of properly sizing and specifying the tools we’re using for this stage. And this all starts with accurate inputs. 

First, we must have a complete understanding of the operating parameters in a system.  More specifically, we want to know the flow rate, operating pressure, operating temperature and the liquids at play.

Particulate filtration is an essential but not exactly a complicated exercise. You can be both cost conscious and effective in this stage as oversizing a filter will achieve both.  When a filter is oversized, operators can be confident that the filter will do its job properly, and they will spend less time replacing them, saving on operating costs.

However, if you apply this principle to coalescing, it will no longer be effective.  We must combine the particles, so knowing the flow rate is essential.  If the rate is too low, the liquid may not separate.  If it’s oversized, the velocity isn’t high enough to coalesce properly.  When sizing the coalescer, we’re looking for optimal efficiency, staying within +/- 15% of the design operating parameters of the system: flowrate, temperature and pressure.  The general principle of sizing is based off Stokes law.  

Coalescing is a critical step in the filtration process. If you’re unsure about your setup, and want to ensure optimization, reach out to one of our experts to help walk you through what will work best for your process. Along with my colleague Joe Bodle, I wrote an article about this subject that was published in International Filtration News last year.  Give it a read if missed it.
 

In many industrial and pneumatic systems, pressure control is essential. But not all pressure regulators are created equal. Two of the most commonly used devices—pressure regulators and back pressure regulators—perform very different roles. Choosing the right one depends on where you need to control pressure in your system.

In this post, we’ll explain the key differences between a pressure regulator and a back pressure regulator, highlight typical applications, and help you determine which is best for your system.

What Is a Pressure Regulator?

A pressure regulator (also known as a pressure reducing regulator) is used to control downstream pressure. It is installed upstream of the equipment that requires consistent, reduced pressure. Its main function is to take high inlet pressure and reduce it to a controlled, lower outlet pressure.

As the downstream pressure drops, the pressure regulator opens to allow more flow. As pressure builds back up, it closes to maintain the desired setpoint.

Common Pressure Regulator Applications:

• Supplying compressed air to pneumatic tools
• Delivering controlled pressure to process instruments
• Maintaining stable gas pressure in distribution systems

Bottom line: A pressure regulator ensures that what comes after it in the system receives a steady, manageable pressure.

What Is a Back Pressure Regulator?

A back-pressure regulator works in the opposite direction. It controls upstream pressure, ensuring that pressure on the inlet side of the valve does not exceed a set level. When the upstream pressure gets too high, the back pressure regulator opens to bleed off excess pressure.

This type of regulator is typically installed downstream of the area where pressure needs to be maintained. Think of it as an adjustable relief valve that keeps upstream systems from becoming over-pressurized.

Common Back Pressure Regulator Applications:

• Controlling pressure in closed-loop systems
• Maintaining pressure in chemical reactors or tanks
• Regulating pump discharge pressure
• Managing backflow in return lines
• Flow controllers

Bottom line: A back-pressure regulator protects the system by holding pressure in, then releasing it only when it rises too high.

Which Regulator Do You Need?

Choosing between a pressure regulator and a back-pressure regulator depends entirely on your system’s requirements:

• If your goal is to deliver a consistent pressure to a downstream device or process, use a pressure regulator.
• If you need to maintain a minimum pressure level in a vessel, loop, or upstream line, a back-pressure regulator is the right choice.

Need Help Selecting the Right Pressure Regulator?

Whether you’re trying to maintain steady output pressure or control upstream pressure build-up, ControlAir can help. We offer a full range of pressure regulators and back-pressure regulators designed for high performance in demanding industrial environments.

Talk to one of our experts today at (855) 737-4714, or fill out our online form to learn more. 

Understanding Linear Motor Terminology for Better Motion System Selection

In industrial automation and motion-control systems we often use terms interchangeably, but words have meaning — and often carry very different technical implications.

• Linear motor actuators
• Linear motor stages
• Linear motor positioners
• Linear servo motor versions of all of the above
• Linear stepper motor versions, too

But, each of these linear motion terms has a nuanced meaning and technical implication when designing machine automation solutions.  If you've ever found yourself asking "What exactly is a linear servo motor positioner versus a linear servo motor actuator versus a linear servo motor stage?" you're not alone. Let’s break this down clearly and simply.

What Is an Industrial Automation Actuator?

The word “actuator” is the most generic and widely used of the terms.

Definition: An actuator is any mechanism that causes motion.

Actuators can be:

• Electric
• Pneumatic
• Hydraulic
• Manual (yes, even a hand crank can technically be an actuator!) 

In the electric linear actuator world (whether servo linear actuator or stepper linear actuator), you’ll find rod-style, rodless, rack & pinion, direct-drive versions — all of which are key in industrial automation linear motion applications.

There are many form factors…

• Rod-style actuators
• Rodless actuators
• Rack & pinion driven
   

…and transmissions…

• Ballscrew
• Belt & pulley
• Rack & pinion
• Direct drive 

In short, “actuator” is your catch-all term. It could be low-end or high-end, simple or complex.
 

What is an Industrial Automation Stage?

A stage is a specific type of actuator with a particular structure and purpose.

Definition: A stage is a motion platform where the load sits on top, and the platform moves back and forth on a base.

Technically, a stage includes: 

• A moving carriage or platform
• A base or frame
• A guide mechanism (bearings, rails)
• And usually, a motor and transmission causing motion

Stages often incorporate more precision components and tighter tolerances than generic actuators.

A linear stage or motorized linear stage is a specific type of actuator with guide rails, load-bearing carriage and base — often used in robotics, precision dispensing, semiconductor manufacturing and other motion-control systems requiring repeatability.
 

What is an Industrial Automation Positioner?

Now here’s where we bundle the full system together.

Definition: A positioner includes the mechanical stage/actuator, plus the control electronics, feedback, and even sometimes networking or communication protocols.

In other words, it’s a complete motion subsystem — not just the mechanics.

A linear positioner system combines the linear stage mechanics with control electronics, feedback encoder or resolver, networking and motion controller — in other words a full motion-positioning subsystem in factory automation or machine automation.

While a simple actuator might move with just a power source, a positioner is designed to move to an exact position, often based on external commands or automation systems. It includes:

• Motion controller
• Feedback device (like an encoder)
• Software or interface
• Safety and home limit sensors 

This is where the difference in application complexity becomes important:

• Actuator = motion
• Stage = motion + structure
• Positioner = motion + structure + control

Definitions at a Glance

Choosing Between an Actuator, Stage, and Positioner

The choice depends on your application requirements. If you simply need linear motion, an actuator might be sufficient. If you need guidance and precision, you move up to a stage. And if you need integrated feedback, closed-loop control, and coordinated automation, then a positioner is the right fit.

When specifying a linear motion system, consider:

• Required stroke length — short or long stroke
• Desired precision and repeatability
• Load capacity and duty cycle
• Motor type (rotary, stepper, or linear motor)
• Control architecture and feedback needs

Matching the right motion component to the right automation task is where application engineering expertise makes all the difference.

Understanding the other words: “Linear,” “Servo,” and “Motor”

Here are a few other foundational terms that often get bundled with actuators, stages and positioners:

Linear: This just means straight-line motion (as opposed to rotary). So everything we’re discussing here involves motion along a linear path but there are rotary equivalents.
Motor: The motor is the source of movement as opposed to it being pneumatic or hydraulic.  There are fluid power motors, but typically a motor is assumed to be electric which are typically either servo or stepper technology.

Servo vs. Stepper

• Servo motors are controlled by closed-loop systems, which means they constantly adjust to maintain precise position, speed, and torque. This is ideal for dynamic, high-speed, or high-accuracy applications.
• Stepper motors are usually controlled by open-loop controllers. They move in steps and are simpler, but typically lower in performance and accuracy. However, there are closed-loop systems that use stepper motors instead of servos. 

So, when we say:

• Linear Servo Motor Actuator – we’re talking about a straight-line motion device powered by a servo motor.
• Linear Stepper Motor Stage – we mean a stage-style mechanism powered by a stepper motor.
   

Now, let’s tackle the most confusing part: the difference between actuator, stage, and positioner.
 

Where Do Servo and Stepper Fit In?

Linear Servo Motor Actuators / Stages / Positioners

• Used when high accuracy, speed, and repeatability are required
• Feature feedback and closed-loop control
• Ideal for industrial automation, robotics, precision dispensing, lab automation, semiconductor, etc.

Linear Stepper Motor Actuators / Stages / Positioners

• More cost-effective
• Suitable for simpler or open-loop applications
• Ideal for basic positioning tasks or low-speed automation
• Not very common
   

Benefits and Why This Matters

Using the right keyword — whether you’re talking about a linear actuator, linear stage, or linear positioner — helps engineers, machine builders and purchasing teams clearly understand what kind of linear motion system you’re specifying and ensures you match the right solution in your automation application engineering.

If you're building or automating machinery and you’re unsure whether you need a linear actuator, stage, or positioner, or if you’re trying to decide between servo and stepper, Valin’s motion control engineers can help.

 

How to Select Linear Servo Motor Stages, Actuators and Positioners?