Double Dump Valves
Double dump valves (or double-flap valves) work within the ash handling process as gravity feed mechanical devices designed for removing hot, abrasive materials from your process, while at the same time preventing undesirable air leakage by maintaining system pressure.
The principle of operation of double dump valves is based on two housing/flap assemblies continually alternating in operation, with one closed and collecting material while the other is open and discharging material.
Double Dump Valve Features
Unlike a rotary valve where eventual air leakage occurs due to constant rubbing between the blades and housing, double dump valves are not subject to the same kind of wear, even in extreme conditions. Double dump valves allow material to flow, while preventing the back flow of air or gas that is critical in many conveying systems. These devices are commonly used wherever dry solids need to be moved between areas of differing air pressure, including ash handling.
Typical double dump valve equipment applications include drop-out box hoppers, dust collectors, baghouses, precipitators and screw conveyors. Common materials collected by double dump valves include fly ash, sawdust, lime, shavings, cement, clinker, sinter and sand. Other types of material can be collected as long as they are granular, not sticky and flow freely by gravity.
Double Dump Valve Sizes and Types
There are three sizes of double dump valves offered (listed below), and three types available for each size.
- The ST (Standard Temperature) type is rated for operating temperatures up to 650°F and includes abrasive resistant internals.
- The HT (High Temperature) double dump valve is rated for operating temperatures between 650°F and 1000°F, and also includes abrasive resistant internals.
- The WF (Wood Fired) type is rated for operating temperatures up to 650°F, but includes internal parts which are better suited to withstand thermal shock caused by fires.
Parts for all sizes and types are always in stock and ready for immediate shipment. Contact us today to see how your system can be improved by using Process Barron double dump valves.
|Double Dump Valves: Standard Sizes|
|Size||Opening Size||Material Capacity||Unit Height|
|8"||8" Square||93lbs / ft3||32"|
|10"||10" square||165lbs / ft3||36"|
|12"||12" Square||300lbs / ft3||44"|
Electric, pnuematic and gravity operation construction features
Each double dump valve can be built for electric, pneumatic or gravity operation. Our unique design also features large, easily removable panels for quick, easy access to service internal flaps and seats. All required maintenance can be performed with the unit in its operating location. Listed below are some of the construction features common to all designs, and those of electric and pneumatic arrangements.
- Ductile cast iron bodies with rugged, heavy walls
- Designed for 650 F operating temperatures as standard
- Ni-Hard flaps and seats for high abrasion resistance
- Stainless steel shafts for high-temperature service and corrosion free sealing surfaces and bearing journals
- All bolted construction, requiring no special tools or welding
- Completely interchangeable parts with close design tolerances
- Designed for around-the-clock operation to keep material evacuated from your process while maintaining an airlock seal
- In-place service and maintenance of flaps and seats
- Dutchman spacers can be added in between the housings to increase the operating capacity
- Valve flaps are powered open and closed by counterweights, which are self-flushing if overloaded
- Operating linkages have spherical rod end bearings for proper alignment
- Factory-set slip clutches prevent damage to the drive in the event the valve becomes jammed
- Gear boxes are spring mounted to absorb possible impact shocks or overloads
- TEFC motors are available in any standard voltage requirement
- Valve flaps are powered open and powered closed by air cylinders, guaranteeing a positive seal
- Each cylinder has two flow control valves to control stroke speed and prevent slamming
- Operates on low volumes of 30 to 50 psig compressed air
- Control packages are available for single or multiple valve operation and can include solenoid valves, timers and relays in a NEMA 12 enclosure
- Cylinder mounted solenoid valves and position indicating switches are also available