Frequently Asked Questions - Safety

Leakage can happen when rotary valve parts wear down, particularly with abrasive or corrosive chemicals. The most important parts to check and maintain regularly are rotors, shaft seals, and bearings. Anti-corrosive coatings such as XTR-Coat can prevent rotor-to-housing tolerances from wearing down too quickly, which is a key aspect of preventing leakage. Four-lobed shaft seals last longer and have a more reliable seal. Finally, outboard bearings have a longer service life and lower risk of failure.

In pharmaceutical, cosmetics, and food processing plants, quick-clean rotary airlock valves boost sanitation by dramatically speeding up the cleaning process. Standard valves can be time-consuming to disassemble, requiring tools and several steps. Quick-clean models are built on a rail system, so you simply turn a handle, slide out the internal rotor, and start cleaning.

For industries like food, pharmaceuticals, and cosmetics, rotary valves need the right coatings and features to prevent cross-contamination. We typically recommend either stainless-steel, Lectrofluor, or XTR-Coat to ensure your valve has the appropriate protection against sticking and corrosion. Smooth internal surfaces are an essential feature of any valve, but especially for sanitation. Finally, if you find yourself switching between batches often, consider a quick-cleaning design to reduce downtime. 

In terms of options and accessories for the food processing industry, food-grade coatings and materials such as stainless-steel, Lectrofluor, and XTR-Coat are the best at preventing contamination. Rotors with U-shaped vanes reduce material packing and make cleaning easier. The valve itself must be properly welded and finished to ensure the surfaces are smooth and durable, which means there will be no cracks or crevasses for bacteria to build up.

Yes. If your facility generates combustible dusts, these safety features are non-negotiable (and unlike other vendors, ACS Valves does not charge extra for them). According to NFPA rules, a compliant rotary valve has metal tips on the rotor assembly, outboard bearings, and rotors with eight vanes or more. Some options will depend on your exact application, but a valve expert can guide you in the right direction. 

Rotary airlock valves can be specified with features that support food safety and sanitation goals. We often recommend stainless-steel materials of construction, special coatings, and valves designed on a rail system for easy disassembly and cleaning.

Rotary valves can be very effective at minimizing leakage when properly configured by an expert.

As a general recommendation to prevent dust leakage, valves should be equipped with ACST-4 shaft seals and an outboard bearing design. You should also check rotor-to-housing tolerances often, as enlarged tolerances can also cause leaks.

Corrosive materials can damage the rotary valve’s internal parts over time, including the rotor-to-housing tolerances. We recommend a coating called XTR-Coat to minimize the effects of acidic, abrasive, or corrosive materials. Its durability prolongs the lifespan of your valve and parts, and its compliance with FDA and USDA regulations also makes it an excellent choice in many food-grade applications.

Whether you’re conveying ingredients for medicated pet foods, kibble with allergen control, or any pet food that must adhere to strict food safety guidelines, it’s important to prevent cross-contamination between batches. Make sure your valve is designed with outboard bearings and reliable shaft seals that are easy to replace.

To quickly wipe away residual product that may harbor bacteria, choose a Quick-Clean design, which allows you to open up the valve without tools for fast and easy cleaning. You might also consider sanitary materials and coatings, such as stainless-steel and XTR-Coat.

Rotor-to-housing tolerances, or clearances, are the distance between your rotor tips and valve housing. Because they wear down over time, you should measure them as part of your regular maintenance routine. Increased tolerances leave a bigger gap for material to leak through, which prevents the valve from working effectively. This can lead to issues with material flow, NFPA compliance and safety, and overall efficiency. Check them often!