An automatic drain valve for removing excess water

To protect your equipment, you'll want a condensate management solution including a manual or automatic drain valve, filters, dryers, and separators.

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Estimated time to read: 5 minutes

Atmospheric air always contains some moisture, also referred to as humidity. When air is compressed, the concentration of these water vapors increases. This moisture can cause all sort of production problems, from corrosion in your piping system to faulty tools and compromised products. 

To protect your equipment, you'll want a condensate management solution including a manual or automatic drain valve, filters, dryers, and separators.

As an example, based on a 47 l/s compressor running at 7 bar in 21 C and 50% humidity, about 9.5 liters of condensate is generated in just 8 hours. If this moisture isn't removed, operational issues may arise.

While this moisture runs through your air compressor and compressed air system, it can contain microorganisms and particles, such as oil droplets. In addition to posing a threat to the end product, this water vapor can also lead to rust and corrosion in your compressor and air system. Therefore, it’s important to make sure it’s thoroughly removed.

As mentioned above, to combat moisture, there's many condensate treatment options, including drains. This article focuses on drain valves, which are often placed at the bottom of the compressor's air receiver tank.

Why use an automatic drain valve?

Using the example above, you can see why it's advised to drain an air compressor at least once a day. A manual valve adds an extra step to your operations checklist. If you install an automatic drain valve, everything happens for you. This occurs with a liquid/float sensor, which signals when the valve opens.

Also, when shopping around, you'll encounter various types including a solenoid automatic drain, motorized time ball valve, and pneumatic zero loss drain, to name a few. While you can continue operations with a standard manual drain valve, it's advised to invest in an automatic valve. It helps prevent unnecessary buildup and corrosion.

Valve installation

It's important to match your valve with your compressor for the correct fit. Typically, a 1/2-inch male NPT inlet pairs with most air compressor machines.

There's also discharge time and internal time to consider. Discharge determines the length of time a valve remains open. Internal time reflects the open frequency. Look for a discharge time between 0.5 and 10 seconds and an internal time between 30 and 45 seconds.

You'll also want to make sure the drain valve operates at the same pressure levels as your air compressor. In most cases, an automatic drain valve with a 200 PSI/13 bar rating or above will work.

When placing the drain, it must be on a downward slope. This helps avoid pocket water from building up. You might also need a reducer for the valve to work correctly.

Completing your setup

Of course, the automatic drain valve is just one piece of handling wastewater from an air compressor. You'll also want to invest in an oil-water separator if using an oil-injected compressor. This will help ensure you're meeting government and environmental guidelines.

Traditional oil-water separators work by using gravity and coalescing filtration. Oil particles bind to a series of filters, allowing for easy separation. Through this method, it's possible to get oil levels down to 5 ppm. This is deemed safe for disposal.

Treating compressor water vapor

If you want to treat moist air coming from your air compressor, you'll want to add proper dryers, filters, and aftercoolers, as stated in the intro. All this equipment is designed to both protect your machine and the end product.

The right setup will be based on several factors including the type and size of the compressor and desired pressure dew point (PDP). This is determined by International Organization for Standardization (ISO) 8573-1 air quality classes for your industry.

We're here to help

We hope this guide is useful in understanding the benefits of an automatic drain valve, like the CDE Electronic zero loss drains. These intelligent drains are energy efficient. They ensure only water, and not compressed air is discharged.

While exploring our full range of drains and air treatment equipment, feel free to reach out at any time. Our team is happy to help point you in the right direction. We're available to answer any questions you may have. Feel free to reach out today.