I’m ordering a new rotary valve. Do I need an air purge kit?

Posted by Megan Thompson on Aug 17, 2020

Air purge kits keep material away from places they shouldn’t be. I wish I’d brought one with me on that trip to Area 51.

But I learned a good lesson: tinfoil hats won’t protect me from deep-space radio waves trying to control my mind, and they certainly won’t prevent my rotary airlock valve from breaking down too quickly.

If I were to start over again, I’d equip my rotary valve with an air purge kit. The kits are designed to blow pressurized air through key areas of the valve to prevent abrasion and related issues.

The result is a longer lifespan for your rotary valve.

Preventing abrasion and infiltration

Air purge kits are often used in the food and construction industries, but they have plenty of other applications. The kits blow pressurized air through the rotary valve to keep material flowing smoothly. This prevents material from sticking or wearing down different parts of the valve.

Unless your material has little to no moisture content — think plastic pellets or dry grain — chances are your valve will greatly benefit from an air purge kit. It also works well in dusty facilities, because it reduces the risk of other materials infiltrating the valve.

Two types of air purge kits

There are two types of air purge kits you need to know about: the shaft seal purge assembly and the rotor pocket purge assembly. You can equip your valve with the shaft seal kit alone or with both the shaft seal and rotor pocket purge kits. Sometimes we’ll recommend the rotor pocket purge kit on its own, but those are rare cases — it’s all situational.

We’ll be happy to explain more when you contact us, but for now let’s move on to an explanation of the two air purge kits and how they work.

Which air purge kit and why?

The shaft seal purge kit blows air past the shaft seal and bearings, which is great if you work in an industry with abrasive or very fine materials. If you’re conveying cement, for example, the kit’s pressurized air keeps material from wearing down the shaft seal and bearings area.

For materials that tend to pack inside the V-shaped groove of a typical rotor, a rotor pocket purge kit also comes in handy. It blows compressed air through the rotor area and prevents build-up inside those pockets. If you have a closed-end rotor — a version with a disc on either end, which we recommend for very abrasive, flake or chip materials — it keeps air moving between the endplates and rotor shroud.

By the way, if you work in a food-grade or sanitary application and need extra help with material build-up, a U-shaped rotor pocket could make your job easier. More on different rotor types here.

What else do I need to know?

Not much, honestly! The air purge kits are available for multiple rotary airlock models manufactured by ACS, including the highly customizable CI Series and its round-flange counterpart, the MD Series. It can also be equipped to a Quick-Clean version for a drastically reduced cleaning time.

The air purge kit’s pressure rating is normally 5 PSI above the conveying line pressure, and we can tell you more about things like air consumption when you get in touch with us to configure your rotary valve. Some of these details really depend on your material and your process.

So, what are you waiting for? Get in touch with a friendly ACS Valves rep to get started.

Categories: Conveying Systems , Durability