Rotary valves are immune to most supernatural forces, like werewolf claws and vampire fangs and even witches’ brews. But if you leave them to their own devices, valves can sometimes get a little … spooky.
Have you noticed strange occurrences in your plant? Weird noises, product losses and creepy pale children staring back at you in the mirror (am I the only one that sees them)? You may need to bust out the Ouija board or make some changes in your process.
Is your valve haunted? Maybe. Okay, probably not — but here’s how to tell if it needs repairs, maintenance or a full
You hear scary sounds
One big sign of trouble is when your rotary valve gets too noisy. If the valve is much louder than usual, barks like a dog or otherwise makes sounds you’ve never heard before, shut down your system and inspect it.
Rotor clearances can increase over time, making them a common culprit in this scenario. You could also be looking at a mechanical problem with the drive chain or drive shaft, a jam involving some kind of foreign object, or product buildup inside the valve.
Once you have pinpointed the issue, check your valve maintenance manual for the appropriate fix.
You find product in places it shouldn’t be
It happens all the time in horror movies: objects move around and end up in places they shouldn’t. There’s a similar problem with rotary airlocks where you expect to see product continue down your conveying line, but it ends up leaking through unsealed areas of the valve instead.
While slightly less alarming than teleporting objects, leaking material costs money and, as a source of combustible dust, increases the risk of fire in your plant. Leaks are often caused by worn shaft seals. When clearances expand too much, the valve will stop sealing properly, reducing capacity and increasing pressure at the seal area.
These symptoms can be indicators of different issues. Depending on the magnitude of the problem, you may need to replace your shaft seals, adjust rotor clearances, or call a medium and run.
Material is getting stuck
Jamming is only cool when Bob Marley is involved. When it happens on your conveying line, too much material buildup can overload your motor, break a chain or bend the rotor to the point that it breaks.
Material jams may result in extra downtime as you stop the process for cleanup. This is more common in certain applications, such as conveying sugar or other sticky or powdery materials. Moist or humid conditions can cause those materials to stick inside the rotor.
The right coatings and features can help prevent jamming, but from a repair or maintenance perspective, just make sure your rotor is clean before checking for problems with your supply source or the piping layout of your conveying line.
The airlock stops rotating
Oh, the horror! If the airlock has stopped rotating, it may be too late to save it. Issues like a broken shaft are serious enough to warrant an entirely new valve.
No need to panic, though. You should also check for electrical issues with your motor or look for a foreign object stuck in the inlet — once your system is fully locked out and tagged, of course. Signs of wear on the chain or gearbox could also mean those components need replacement, so it’s worth exploring all the possibilities first.
When the time comes to replace your rotary valve, speak with a specialist who can help you custom-build a valve that suits your particular application. The right construction will reduce the need for repairs, downtime and wasted material — and save you money in the long run.
Still stuck? Call for professional help
If none of these methods work, you should either call an exorcist or a rotary valve expert. We recommend the latter.