Frequently Asked Questions - Conveying Systems

Material buildup and flow issues like bridging can happen when plastic resins flow through the system too quickly, or when your equipment lacks the proper accessories to handle flow issues. Ensure rotary valves are properly sized for your material, system, and desired rate of flow, and consider accessories such as shear protectors and air purge kits to prevent issues such as shearing, jamming, and buildup.

The CI and MD Series rotary airlock valves excel at maintaining the consistent, uniform flow needed for metering pharmaceutical ingredients, and they can be customized to fit most applications. In more specialized cases, you might need a BT Series blow-through valve to optimize air flow, or a mini- or micro-sized valve for small test batches. There are also rotors that limit pocket size or control material flow in various ways to suit your needs. Your supplier should be able to explain the best choice for your application.

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. 

Standard rotary valves can be time-consuming to maintain because they require tools to disassemble. Quick-cleaning models speed up the cleaning process by making it easy to access the valve’s internals. In the case of a Quick-Clean Valve with RotorRail, for example, you just need to turn a handle and slide out the rotor, which is set up on a rail system. It only takes a minute before you can start cleaning.

In pet food processing, we typically see the best results with stainless-steel, Lectrofluor, or a special anti-corrosive coating called XTR-Coat. All three can help you comply with food safety regulations and prevent materials from sticking to the valve. To choose the right one, we’ll look at your application and material characteristics such as weight and moisture.

If you swap ingredients often, you can cut downtime significantly by installing a quick-cleaning rotary valve. These are built on a rail system with handles that make it easy to open up the valve, clean the internal surfaces, and close it up without using tools. Another option is a valve with multiple compartments for split feeds, where each compartment can handle a different ingredient.

Not all rotary valves are designed to be interchangeable between ingredients, but ACS Valves has options for plants with split conveying feeds or multiple ingredients. The Multi-Port valve is one to consider, since it features multiple separate compartments in a single valve, making it easier to convey materials from different lines into a single valve. Many of our customers also use the Quick-Clean valve to convey multiple ingredients, because it can be cleaned and sanitized quickly thanks to its rail-based design.

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.

Capacity is the volume of material your rotary valve can handle per rotation. The calculation involves the rate of conveying, material bulk density, valve efficiency, and RPM of your rotor. We can help you with the math, but if you're just looking for a valve sizing recommendation, you can use our handy calculator tool.

It depends! Do you want a valve with an easy-to-clean design? A valve with multiple ports for split conveying lines? Maybe a valve for heavy-duty applications, for corrosive material, or for metering small batches?

We could go on, but the best way to determine which valve you need is to speak with an ACS Valves rep. Give us the details and we’ll help you choose a rotary valve that’s optimized for your needs.

Because rotary valves come in so many different types and sizes, we don’t list prices online. Please contact an ACS Valves rep to request a quote. We’re happy to walk you through exactly what you need and why.

There are so many! Our standard CI Series valve is popular with its efficient construction and plenty of customization options. But there are dozens of other options, and they depend on:

1. Your application (e.g., construction, pet food, or cannabis processing?)
2. Your material (e.g., cement, plastic, or flour?)
3. Your system (bulk material, dust collector, or pneumatic conveyor?)
4. Your desired valve type (airlock with metering, metering/feeding, or airlock?)

You could go even further down the rabbit hole and customize valves with different rotors, coatings, and accessories for maximum efficiency. The easiest approach is to contact an ACS Valves rep to discuss your options — we’ll only recommend what your process actually needs.

A valve is a transfer point in your material handling system, moving bulk solids from containers (think bins, hoppers, and silos) to the conveyor below. It may also move material from one container to another.

Valves can be used to provide a pressurized seal between those points, help control the flow of material, or both. Basically, they help you move material efficiently and safely, preventing product loss.

This is a great question because they’re also called airlocks (or rotary airlock valves, or rotary airlock feeders) — just to make it extra confusing. The catch-all term is rotary valve, which is what we use most often.

The exact term changes depending on how the valve is used. Anything with the word “airlock” in the name is used to maintain a pressure differential between two separate compartments. Feeders are more about controlling the rate of material flow from one place to the next. If a valve does both, you would call it a rotary airlock feeder.

At ACS Valves, we have a lot of multifunctional rotary valves that can serve any of these roles, as well as more specialized valves for airlock or feeding/metering purposes. If you’re not sure what you need, give us a call and we’ll help you figure it out!

That depends on you. Do you need to control the rate of material flow (feeder), maintain a pressure differential between compartments (airlock), or a combo of both (airlock feeder)?

Not sure? That’s okay — give us some details about your process needs, and we’ll make a recommendation.

The capped pipe is called a housing vent port. Rotor pockets can sometimes contain a volume of pressured air, which can impede material flow into the airlock inlet, reducing your efficiency. Also, in conveying systems that run at 6 PSI and higher, large releases of air up the return side of the airlock can cause pulsing in the material flow into the conveying line. Using a vent helps solve both of these issues, and is also helpful in improving your fill efficiency.

Too much clearance between the rotor, endplates and or housing can result in air loss. Measure the rotor to endplate and rotor to housing clearances to confirm that they are an NFPA compliant 0.0079 inches. If the clearance is larger than this, it might be time to replace your rotor, rotary valve, or have it sent back to ACS for a repair or evaluation. Make sure to stick to a maintenance schedule and check your clearances at least every three months.

Sometimes the rotation of the rotor is reduced due to an overload of material, or larger pieces of material being fed through the valve, jamming in the clearances. In this case, shear pin sprockets will shear the pin on the sprocket, reducing the risk of damage to the rotor.

Shear protectors reduce the flow of material at the valve's inlet. Reduced flow allows for better pocket fill and also reduces the risk of product jams in your housing clearances–ultimately protecting your product from damage.