An accessory guide for your rotary valves
When it comes to conveying different types of material, some love flowing through your rotary valves with ease.
Others can get a little overzealous and flow much too easily, damaging your valves by creating a miniature sandstorm inside its housing.
The third kind is stubborn, passive aggressive, and causes material jams, ultimately disallowing any other material from continuing on with their flow.
That’s why we’ve compiled a list of accessories that can help your rotary valves regulate flow, so that you’re getting the best product output, every time.
The shear protector is used for more granular materials such as plastic pellets, plastic flakes, wood pellets and larger, bulkier pieces of material.
It comprises of a mild-steel plate that sits on the valve’s inlet port. It includes a bent wiper blade, with a flexible polyurethane tip. Its function is to prevent rotor jamming by stopping materials from getting pinched within the clearances of the rotor and housing. As material enters the rotor pockets through the inlet port, the shear protector’s wiper blade sweeps any overflow granules into the next pocket, preventing jams.
Shear Pin Sprocket
For any material that is going to be introduced into a pressure conveying system, a blow-thru adapter is needed. This allows your material to drop out of the valve’s outlet port and blow wherever it needs to go in your plant. This accessory should also be accompanied with a housing vent port in your valve’s housing to relieve the air coming up from the conveying line and leaking into the empty side of the valve as it rotates back up.
Dust Hazard Analyses (DHA) are mandatory for new and existing facilities that handle, generate, or store combustible dusts under NFPA 652. They outline what the fire and explosion risks are of each particular dust, and define methods to prevent or mitigate hazards or accidents. See our list of types of DHA’s below.
An air purge sits either behind the shaft seal or the rotor pocket of your valve, blowing compressed air against it.
The rotor pocket connection is highly recommended with a closed end rotor, as it should help prevent material build up between the rotor shroud and endplate. It is also recommended for sticky or fluffy materials, as it helps keep the material aerated.
The shaft seal purge is used to keep material away from the shaft seal which prolongs its life. This is important when you’re conveying fine powders that are small enough to build up on the shaft seal and put you at risk of contamination or a combustible dust explosion. The air purge keeps your shaft seal clean, and keeps your machinery working.
Discharge Flange Guard
Used in gravity applications, a discharge flange guard acts as a preventive safety measure. It is essentially a grate that sits on the outlet port and prevents access to the rotor, should material get stuck and someone feels so inclined to reach their hand up and loosen it without taking the proper safety precautions—which we would never recommend.
Zero Speed Switch
Industry 4.0 is here, which is why a zero-speed switch comes in handy for monitoring your valve. It lets your PLC system know when your shaft stops rotating, and will send an alarm out to prevent issues down the line.
There are more options than packing gland for your rotary valves, but we won’t go into detail here. Read our crash course on seal types for rotary valves here.
Depending on your material type, it’s a good idea to look at different rotor types that can treat your product with the most respect. For example, if you’re looking for more uniform output, the Staggered Pocket Rotor might be for you. We have a breakdown of different rotor types here.