Double Flap Airlock Valve

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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 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, ranging from fine powders to chunky, odd-shape large particles with various types of equipment operating under positive or negative pressure. The primary purpose is to discharge a flow of material while maintaining an airlock at a transition point, preserving the pressure differential above and below the valve in the system. Plattco Double Flap Airlocks are superior to alternatives for bulky or abrasive materials that would jam or damage a rotary airlock.

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How It Works

Plattco Double Flap Valves operate using two distinct chambers. First, the top chamber opens to allow collected material to drop through into the bottom valve. The top valve then re-closes to prevent leakage of fugitive and tramp air through the valve. Second, the bottom chamber opens to allow material to pass completely through the valve to the system below. The bottom valve then re-closes to prevent leakage of fugitive and tramp air. Then, it continuously cycles to maintain a steady flow of material and maintaining a positive seal on the system. One valve is always in the closed position, which allows the Plattco double flap airlock valve to maintain a positive seal.

What do 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, and/or is pressurized 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 sequence of filling & emptying the valve
  • All cast construction, using proprietary alloys for consistency, durability and wear resistance
  • Propriety Seat and Flapper design, precision machined flat to eliminate air leakage and allow for infinite renewability in-line.
  • Propriety Seat & Flapper design (the seal) allows for the components to be resurfaced to a like new condition and can be replaced without moving the valve or taking it out of service
  • Our Field Service & Repair, supplementing or eliminating 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
  • Outboard 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 the 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 Double Flap Valve & have over 60 years experience building valves and 120 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 a valve with many choices for optimal performance:
  • Four valve models and several slide gates – all available with fully customizable options
  • Standard & custom sizes available (also available in metric)
  • Dutchman (spool pieces) to increase volume throughput for each model of valve
  • Variety of alloys - from cast iron to stainless steel - to handle extremes of material properties & temperatures
  • Pneumatic, electric, hydraulic, gravity, electro-pneumatic options for actuation.  All actuation packages are delivered completely assembled and fully calibrated to insure quick and accurate startup.
  • Shaft seal design options

Every application comes with a unique set of needs. Factors like material characteristics, velocity, flow rates, temperatures, particle size/shape, particle hardness, and system design are all evaluated and optimized by our skilled engineering staff, allowing you to reap the benefits of customization of any of our (4) standard models.

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


Premiere 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 PSI (2.75 Bar) or temperatures up to 1800F/980C.

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R-Series Radial Valve


Radial Valves

Same features of the H-Series with an air tight radial (round) opening with round internal mating components (seat/flapper).  This valve received its name based on its round (radial) opening. Rated for up to 40 PSI (2.75 Bar) or temperatures up to 1800F/980C.

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S8-Series Low Profile Valve


Low Profile Valves

Same rugged design as our famous H-Series Flap Valve at roughly half the height for applications when headroom is restricted. This valve is named for its “S”horter profile than our original H-Series. Rated for up to 15 PSI (1.0 Bar) or temperatures up to 1800F/980C.

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PCV-Series Pollution Control Valve


Pollution Control Valves & Rotary Valve Replacement

The perfect valve for pollution control systems and other low pressure differential (< 2 psi/.14 bar) applications, with the same profile as the S8-Series. Rated for up to 750F/400C.

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Performance & Safety Enhancements - Available on Most Models

Abrasion Resistant Coatings
Air Cooling Jets Rod
Air Cylinder Heat Shields
Cylinder Rod Boots
Dust Deflectors
Easy Access Covers (also in hinged)

End Bearing Seats
EZ Seat
Filter Regulators
Four Way Directional Valves
High Temperature Bearings

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

Safety Guards
Viton Air Cylinders
Zero Speed Switches