Duall OilMaster™ scrubbers are manufactured from Type 2, Grade 1, high-impact polyvinyl chloride (PVC) conforming to ASTM D1784, Cell 1433D, polypropylene or CPVC. All vessels are of hot gas welded construction and are hydrostatically tested at the factory by filling to the air inlet nozzle. Stainless steel or other metal construction is also available.

Multi-Stage Mist Eliminator
The first and last stages consist of random-dumped, high-efficiency filamentous type packing.
The packing is fabricated from polypropylene or other materials and is installed at the factory.
The second stage is a high-efficiency mist eliminator to coalesce and eliminate entrained oil droplets. It is fabricated from polypropylene and is installed within a removable cartridge to facilitate maintenance. The cartridge is mechanically sealed using an interlocking track system to prevent by-passing.

Principle of Operation
Oil droplets carried in the gas stream, by virtue of their mass and velocity, impact on the media in the first and second stages of the OilMaster™, the first stage collecting the larger droplets with the second stage collecting the smaller droplets. Collected oil may be recovered for reuse in the plant if desired, requiring only filtration. Stage 3 serves as a final entrainment separator for collecting oil and wash liquid which can become entrained in the gas stream during the washdown of the Stage 2 mesh type media.

Because it utilizes impaction, the OilMaster™ performance is sensitive to the gas velocity. Units are designed to operate at face velocities for optimum performance. Differential pressure gauges are provided with the unit which give an indirect measure of gas velocity, as well as the condition of the media.

Periodically, the media must be washed to maintain proper performance and throughput. Stages 1 and 2 may be washed on-line, eliminating the need to shut down the system. For very dirty air streams, continuous recirculation and filtration of the wash liquid is recommended.

Access
Access doors with clear PVC covers are provided for inspection of the spray nozzles, packing, and mist eliminators. Gaskets and stainless steel hardware are provided by Duall.

Differential Pressure Gauge
Differential pressure gauges for monitoring pressure drop across each mist eliminator are provided. They are factory-mounted on the scrubber. A liquid trap to prevent water entering the air line is also factory-mounted to the scrubber. Vinyl tubing is provided by Duall.

Washdown System and Controls
Spray nozzles are open-orifice, non-clogging type. Minimum nozzle pressure is 10 psig. Water may be used for water-soluble oils, whereas clean mineral oil must be used for non water-soluble oils. Each header assembly is constructed from Schedule 80 PVC pipe with PVC nozzles. They are installed at the factory. Full bottom drains allow the scrubber to drain completely. Flow meters for indicating or adjusting washdown rate for each scrubbing stage are optional. Recirculation pump, filters and tank for the wash liquid are also optional.

Equipment for automatic control of scrubber washdown is optional. The package includes a control panel with adjustable timers to automatically wash down OilMaster™ Stages 1 and 2 during operation.

Components are in a NEMA 4 enclosure with a main disconnect switch, control voltage transformer, fan motor starter, solenoid valves, *programmable logic controller (PLC), terminal blocks for wiring to external components and an interlock to prevent washdown of Stage #3 final mist eliminator.

*PLC is used instead of relays.