Rotary Airlock Valve Feeders
STT supports your ongoing maintenance needs with a complete offering of rotary airlock valves and other accessories. Available in a variety of models and sizes, you can count on STT to provide the right solution to your airlock and metering needs.
Airlock Rotary Valve Solutions for Your Material Processing Needs
Rotary airlock valves are essential for your dry bulk material handling and pneumatic conveying systems to run safely and efficiently. Rotary airlock valves, also known as rotary airlocks, rotary feeders, rotary valves, and countless other variations, regulate the flow of and a variety of material from one chamber to the next while preventing air leakage. Beyond controlling the flow of material, rotary valves are also important safety mechanisms acting as a flame barrier in the event of a dangerous dust explosion.
ROTARY AIRLOCK PRODUCTS
Why Choose an Industrial Rotary Airlock Valve From STT?
STT understands rotary airlock valves play a crucial role in the performance of your bulk material handling and pneumatic conveying systems. Selecting the correct rotary airlock valve is key to maintaining a productive and reliable plant operation. We pride ourselves on the attention we give every valve that leaves our shop.
Our 50 plus years of experience in the design of both dust collection and pneumatic conveying systems, as well as, the design and manufacture of rotary airlock valves, provides us with the engineering expertise to understand which type of rotary valves will best meet your airlock and feeder needs. We make it our priority to understand your processes and your applications so we can confidently recommend the right solution that best addresses your material processing needs whether it be a new valve or the need to refurbish and repair an existing valve.
The Features and Benefits of Our Rotary Airlock Valves and Feeders
- A variety of designs provides options addressing your specific needs.
- Cast iron construction offers rugged design providing maximum structural stability.
- Precision-machined housing minimizes rotor-to-barrel clearances, limiting leakage.
- Outboard bearing design protects bearings from contaminants extending maintenance cycles.
- Packing gland type seals makes for easy maintenance saving on costs.
- Open throat valve inlet design ensures material flows to rotor pockets maximizing performance.
- Handles pressure differentials up to 15 psi making it well suited for pneumatic conveying operations.
- Chain and sprocket drive offers a smaller footprint and greater speed selection providing flexibility to the applications being used in your process.
Industries We Serve
Our rotary airlock valves are used throughout a variety of industrial, agricultural, and specialty material handling systems including, but not limited to:
- Water Treatment
- Chemical Processing
- Grain Handling
- General Industrial
- Oil and Gas
- Glass and Ceramics
- Pulp and Paper
Key Considerations for Rotary Airlock Valve Selection
Selecting the right rotary airlock valve for your dry bulk material handling and pneumatic conveying systems is essential. Several key considerations need to be taken into account when selecting rotary airlock valves:
- Type of bulk material being processed
- Type of application
- Operating temperature
- Level of abrasion resistance required
- Material density and moisture levels
Sizing and Valve Design Considerations
Selecting the right valve size and design is critical to running your feeding and metering systems safely and efficiently while minimizing pressure loss. When selecting your valve, consider the following:
- If clearances are not set correctly, air can leak through the valves. Air loss through the valve can contribute to inadequacies in feed rate capacity, create unstable flow conditions, create blockages in conveying line and cause excessive wear on the interior surfaces. Pressure, rotor clearances and material properties are all contributing factors to the amount of rotary valve leakage.
- Maintaining a constant vacuum or air pressure differential between the inlet and outlet ports while continuously moving material is critical to proper functioning of a rotary valve.
- For abrasive applications, hard chrome interior surfaces are necessary.
- Open end rotors are typically used for abrasive materials. With open end rotor design, the material encounters the housing bore and the inside surfaces of both end plates.
- Closed end rotors are used for handling pellets. In a closed end rotor design, the only blade area that is affected is the blade tip adjacent to the housing bore. The housing end plates are not affected.
Not sure what type or size of rotary valve you need. Ask our experts. We’re here to help.
Rotary Airlock Valve Feeders
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Contact STT today to discuss your airlock application with one of our technical experts. We’re here to help you select the best rotary airlock solution for your application.
How does a rotary airlock valve work?
Material is fed from a silo hopper through the valve’s inlet and dropped into a rotor pocket. As the blades rotate, material is carried in the rotor pockets toward the outlet of the valve. Shaft seals prevent material and air leakage into or out of the valve ensuring a proper airlock and uniform feed.
What happens if you use the wrong sized rotary valve?
An incorrectly sized rotary valve can result in poor efficiency, extra maintenance and operator hours, product degradation, frequent wear and tear and equipment replacement and decreased production due to frequent shutdowns.
How is rotary airlock capacity calculated?
A rotary airlock capacity is calculated using the fixed volume of the rotary valve cavity (at 100% fill efficiency) and that volume when one full revolution of the blade is made. You then obtain a “volume per revolution” in either ft3/rev or m3/rev to help calculate the capacity in lbs./hr. or kg/hr.
Now consider the following calculation:
CAP = Rotary airlock valve capacity in lbs./hr. [kg/hr.]
BD = Bulk density of the product going through the rotary valve in lbs./ft3 [kg/m3]
V = Volume of rotary airlock valve based on one complete cycle of the rotor ft3/rev [m3/rev]
EF = Fill efficiency of the rotary airlock valve, in percent
SP = Rotational speed of the rotary airlock valve, in RPM
CAP = BD x V x EF x SP x 60 (min/hr.)
Example: Require a capacity output of 19,000 lbs./hr. [8,618 kg/hr.] for quicklime at 55 lbs./ft3 [881 kg/m3] with a fill efficiency or 85%. Now, it should be considered that a rotary airlock valve should be operating at a max speed approximately 20 RPM to maximize its fill efficiency. Also, we need to consider the upstream and downstream equipment connections for the rotary valve. Assuming an 8” connection size is best; we can evaluate the size of an RV-308:
BD = 55 lbs./ft3
V = 0.3 ft3/rev
EF = 0.85
SP = 20 RPM
CAP = 55 x 0.3 x 0.85 x 20 x 60 min/hr. = 19,800 lbs./hr. [8,981 kg/hr.]
Therefore an 8” rotary valve would be well suited for the application.