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Double Flap Airlock Valve

Solving Dry Material Handling Problems That No Other Valve Can

AKA Double Pendulum Valve, Double Gate Valve, Double Flap Gate, Double Dump Valves, Tipping Valves, Trickle Valves - all names used to refer to the product we invented more than 60 years ago. The equipment may go by other names, but there is only one Plattco Double Flap Airlock® Valve!

The primary reason companies buy Plattco Double Flap Airlock® Valves is the airlock technology - essential to having a tight production system. Plattco Double Flap Airlock® Valves are designed to create a seal that will eliminate emissions, tramp, and fugitive air into your systems, while continuing to convey dry material.

Dry Material Handling Solution

Double flap airlock valves are most commonly used in industrial applications for dry, bulk material handling applications handling materials ranging from fine powders to chunky, odd-shape large particles with various types of equipment operating under positive or negative pressure. Its primary purpose is to maintain an airlock at a system transition point, preserving the pressure differential above and below the valve while continuously discharging material.

Plattco Double Flap Airlock® Valves are superior to alternatives for bulky or abrasive materials that would jam or damage a rotary airlock.

Download Hinged Easy Access FlyerRead about Valve MAintenanceSee Capacity Chart InformationGet Valve QuoteDOWNLOAD APPLICATION SHEET

How It Works

Plattco Double Flap Airlock® Valves operate using two stacked valves.

At startup, both valves are closed.

First, the top valve opens allowing collected material to drop through to the bottom valve. The top valve then re-closes to prevent leakage of fugitive and tramp air through to the system above.

Second, the bottom valve opens allowing material to continue through to the system below. The bottom valve then re-closes, again, to prevent leakage of fugitive and tramp air, and the cycle begins again.

Valves continuously cycle and one valve is always closed to maintain a steady flow of material and maintain a positive seal on the system.

What you get with a Plattco Double Flap Valve:

  • No rotary action, eliminating the need to build a clearance (leakage) into the valve.
  • Housing is not part of the seal so it can last for decades in the worst operational environments.
  • Airlock is maintained even if the material is abrasive, corrosive, pressurized, and/or subject to high temperatures.
  • Full throat opening eliminates bridging, jamming, & material build up, allowing the passage of large, chunky, fibrous materials and/or foreign objects that may enter the system.
  • Double flaps ensure the seal is never broken through the cycle of filling & emptying the valve.
  • All cast construction, using proprietary alloys for consistency, durability and wear resistance.
  • Seat and flapper design, precision machined flat to eliminate air leakage and allow for renewability in-line.
  • Our Field Service & Repair supplement or eliminate the routine maintenance burden from our customers.
  • The inside of the valve (including seat & flapper) is reached through access covers in the body of the valve – making it safer, easier, and more convenient to perform inspections and maintenance.
  • In pressurized applications our patented mechanical shaft seal eliminates the potential for shaft seal leakage.
  • Externally mounted shaft bearings allow for air circulation.
  • Numerous maintenance friendly features: stainless steel shafts, bushings on the arms, external seat screws, and pipe plugs for removal of flapper pins.
  • We engineer, design, & manufacture our valves on our original campus in Plattsburgh, NY.
  • We customize solutions to the specifics of your application based on proven technology. You get the advantages of a customized solution combined with the benefits of our expertise in similar applications.
  • We invented the Plattco Double Flap Airlock® Valve. We have over 60 years experience engineering and building valves, as well as over 100 years of metallurgical experience. We have thousands of successful applications, in dozens of industries throughout the world.
  • We make our living solving material handling problems that no other valve can handle. Plattco concentrates on designing, engineering, & delivering the best valve in the world.
  • Over the years we have developed & proven valves with many choices for optimal performance:
  • Multiple valve series and slidegates models available with fully customizable options.
  • Standard & custom sizes. Also available in metric.
  • Dutchman (spool pieces) to increase volume throughput for each valve series.
  • Variety of alloys - from cast iron to stainless steel - to handle extremes of material properties & temperatures.
  • Variety of actuation options available that are designed, assembled, and fully calibrated from the factory to ensure quick and accurate startup.
  • Shaft seal design options.

Every application comes with a unique set of needs. Factors like system flow rates, required outputs, temperatures, and pressures, as well as material characteristics like particle size, shape, bulk density, flowability, and hardness, are all evaluated and considered by our skilled in-house engineering team, giving you peace of mind the right valve is designed to fit your needs.

Our Capacity Chart will help you select the exact valve which will handle the amount of material your application demands.

H-Series Premiere Flap Valve

H-Series

Premier Flap Valves

Ideal for dry material handling with successful applications in industries around the world. The robust design of the H-Series is the perfect selection for large volume, large particle sizes, and the most demanding conditions. Rated for up to 40 PSIG / 2.75 Barg application pressure differentials and material temperatures up to 1800°F / 980°C.

Learn More
S8-Series Low Profile Valve

S8-Series

Low-Profile Valves

Same rugged design as our famous H-Series flap valve at roughly half the height for applications where headroom is restricted. This valve is named for its “S”horter profile than our original H-Series. Rated for up to 15 PSIG / 1.0 Barg application pressure differentials and material temperatures up to 1800°F / 980°C.

Learn More
PCV-Series Pollution Control Valve

PCV-Series

Pollution Control Valves & Rotary Valve Replacement

The perfect valve for pollution control systems and other low pressure differential 2 PSIG / 0.14 Barg applications, with the same profile as the S8-Series. Rated for up to 750°F / 400°C.

Learn More

For a side-by-side comparison of our products, download our Complete Product Catalog.

Performance & Safety Enhancements
Available on Most Series

Abrasion Resistant Coatings
Air Cooling Jets
Cylinder Heat Shields
Cylinder Rod Boots
Dust Deflectors

Easy Access Covers (also available hinged)
EZ Seat
Filter Regulators
High Temperature Bearings

Limit Switches
Mechanical Shaft Seals
NEMA Enclosures
Optional Gear Ratios
Position Indicator Switches
Proximity Switches

Safety Guards
Solenoids
Timers
Venting
Viton Air Cylinders
Zero Speed Switches