Duall Model HL Hydro-Lance™ scrubbers are manufactured from Type II Grade I PVC, polypropylene, CORZAN™ CPVC, mild steel and stainless steel. PVC materials conform to ASTM P2146. Gray PVC is standard for all equipment that is located indoors. White PVC, which contains titanium dioxide to inhibit degradation by ultraviolet light radiation, is used for equipment to be installed outdoors. All thermoplastic vessels are of hot-gas welded construction. All vessels are hydrostatically tested at the factory by filling to air inlet nozzle. They are skid mounted to facilitate installation by the contractor. Flange sealant is 100% silicone rubber or 2" x 3" x 3/8" neoprene gaskets. Inlet and outlet thermoplastic flanges require field drilling by the contractor.

Structural Design
The structural design is based on operation at a maximum process temperature of 120°F for PVC, 160°F for polypropylene and 200°F for CORZAN™ CPVC, with a 150 mph wind load, or in seismic zone 4. A load safety factor of three (3) is applied to the design. Anchor bolts and foundation are not provided by Duall.

Demister
Model HL scrubbers have an integral, high efficiency chevron blade mist eliminator. The mist eliminator will remove 99% of all entrained droplets of scrubber solution 20 microns and larger. The mist eliminator will be factory-installed, and externally removable through the top of the vessel.

Access
Access doors with clear covers are provided for inspecting the venturi suction and spray action, as well as for washing down scrubber internals and mist eliminator, if required. Gaskets are 100% silicone rubber sealant or neoprene.

Removable Internals
The Venturi assembly and mist eliminator are easily removed without entering the device, if necessary, for maintenance, replacement.

Liquid Level Control System
All Model HL scrubbers are provided with a multi-point liquid level sensor and pre-plumbed brass solenoid valve. The system provides automatic water addition to make up for evaporation losses as well as a high level alarm signal.

Differential Pressure Indicator
A magnehelic gauge for visual indication of pressure drop is preinstalled on every unit.

Connections
Inlet and outlet thermoplastic flanges must be field-drilled by the contractor. This will prevent alignment problems with mating ductwork. Plumbing connections 1/2" to 4" are threaded couplings, while 6" and larger are 150 pound ANSI flanges. The exception is the conical bottom drain fittings, all of which are 150 pound ANSI flanges. Mating flanges, hardware, and gaskets are not provided by Duall.

Optional Accessories
The following items are not included with the standard unit, but are available from the factory:

• AMCA certified material handling fan.
  
• Skid-mounting with fan and interconnecting duct.
  
• Automatic electric or pneumatic actuated drain valve.
  
• Quick opening, clean-in-place access doors.
  
• Manual and automatic sludge drag-out options.
  
• Photohelic differential pressure gauge with high/low alarm contacts.
  
• Automatic hydrogen gas venting for reactive metals collection.
  
• Mist eliminator in cartridge removable through side of vessel.
  
• Electric heat tracing, insulation, and sump heater for freeze protection. Field connection to electrical power source is required.
  
• Control panel in a NEMA 4 enclosure. A fused main disconnect switch is provided. Incoming power to the panel is 460 volt, 3 phase, 60 Hz. Control voltage transformer provides 120 volt power for instruments. Internal components of the panel are pre-wired. The controls provided in the panel would typically include illuminated ON/OFF switch for fan, fan motor starter, illuminated HAND/OFF/AUTO switch for make-up water solenoid valve and drain valve, adjustable drain valve timer, and alarm lights and horn for level and differential pressure alarms.

Maintenance
Maintenance is minimal. Care and cleaning of exhaust fan drive systems. Access to level switches, pressure gauges, and the Venturi throat are as easy as turning a bolt.