Rotary Valve / Airlocks
Called by many names: Rotary Airlock, Rotary Valve, Star Valve, Star Feeder, Vane Feeder, rotary valves have been called many things over the years, but no matter what you call them, one needs to understand it’s how you apply them that determines what you call them. And what you call them determines how you select the correct one.
One of the most famous “truths” about a rotary valve is: A rotary valve can be used as a metering feeder to control how much material is passed from point A to point B, but it is not very accurate. A rotary valve can be used as an airlock to separate a high pressure area from a low pressure area, but unfortunately it leaks. So while it is not an accurate feeder and it’s not a good airlock, it’s the only valve that can do both at the same time making it an ideal component of a pneumatic conveying system.
A rotary valve, installed at the beginning of pressure system, where its job is to feed material into a pneumatic conveying system while at the same time taking material from one pressure into the high pressure of the pneumatic conveying system, or a rotary valve installed under a vacuum receiver on a vacuum system whose job it is to separate the high vacuum from atmospheric pressure is a “rotary airlock” or “rotary airlock feeder”. A rotary valve installed at the beginning of a vacuum system whose job it is to meter product into the pneumatic conveying system or a valve installed at the end of a pressure system under a filter receiver are at atmospheric pressure or within a few inches of water of atmospheric are “rotary valves”
When the valve leaves the manufacturing facility, it can be used as either a feeder or an airlock. We do not make a different valve for the different application, but your choice of valve and how you calculate the speed you need to turn it are different.
- Any rotary valve used as an airlock will have lower fill efficiency than a valve used as a feeder
- Any rotary valve used as an airlock will wear out faster than a valve used as a feeder
- All rotary valves used as an airlock leak air and the volume of leakage is directly proportional to the pressure difference across the airlock
- Airlock leakage has NOTHING to do with how fast the airlock is turning
Type 1 Airlock
The Type-1 is a basic, yet versatile rotary valve. With a wide range of options and accessories, the Type-1 will operate efficiently in your system.
Type 2 Airlock
The Type-2 is our most popular abrasion resistant rotary valve. While it is not our most abrasive resistant valve, neither are most of the products that are considered too abrasive for a standard valve.
The Type-3 is our valve with two personalities. Take a standard Type-1 airlock, change the rotor to 304 stainless steel and coat the cast iron end-plates and housing with Nedox® chrome; the rotary valve becomes both corrosion resistant and food grade. You get the performance of a stainless steel valve for the cost of cast iron.
Type 4 Airlock
The Type-4 is our complete Stainless Steel rotary valve with the rotor made out of 304 Stainless Steel with the housing, and end-plates made from cast 316 stainless steel.
Type 5 Airlock
The Type-5 is our complete Stainless Steel rotary valve with the rotor, housing and endplates all made out of 316 Stainless Steel. It is available in our two most popular airlock sizes (our 9” and 12” valves)
Type 6 Airlock
The Type-6 is our abrasion resistant rotary valve is made for the most abrasive environments one would put a rotary valve into. More often than not, the Type-6 has become the “paramedic” valve
Type 8 Airlock
The Type-8 is our newest abrasion resistant rotary valve made for the most abrasive environments one would put a rotary valve into. It was developed to fill the gaps in sizes that were not available with our Type-6.
Dust Collection Applications
The new DC Series have been completely redesigned to provide more efficient and economical solutions for all dust collection applications. This includes groundbreaking features including our all new wiper tip technology.
Smoot offers the cavity air purge process on its entire line of closed end rotary valves to reduce abrasion on the rotor, cylinder, and endplates. This patented design uses low-pressure air from the convey blower and purges the material from the cavity between the rotor shroud and the housing end plates.
The following is a list of available Smoot airlock accessories.