Basic HIT Scrubber Operation click Photo #1 Use Browser return button Note:
Drawings at bottom of page. To enhance the overall performance, keep condensed hydrocarbons in suspension and ensure internal surfaces are kept relatively clean, we utilize a non-toxic, non-foaming surfactant. This surfactant is an essential aspect of the overall operating effectiveness and efficiency of our scrubber. An exhaust air stream enters the unit and passes through a pre-wet section which provides some initial scrubbing and effective wetting of internal surfaces below the scrubbing trays. Keeping surfaces wetted is essential to minimize material build up. The process air stream then enters the impingement tray section where a very aggressive scrubbing action occurs between this air stream and a flowing bed of water. The trays are perforated metal which atomizes the air stream into small columns of air that interacts with the flowing water over the surface. This scrubbing action provides the most efficient removal of pollutants for the amount of energy consumed of any other comparable device. Since there is an aggressive scrubbing action many air borne droplets of water are carried past the scrubbing tray toward the outlet. There is a low pressure drop demister section, that consists of three rows of offset chevrons, which removes these droplets from the air stream. At the end of the scrubbing section is a weir, which sets the depth of the scrubbing sump, and an overflow gutter for the removal of collected pollutants. The water in the sump is re-circulated by a small horsepower pump through a piping system to the pre-wet section and scrubbing trays. This circulated water flows back into the sump by gravity in a closed loop manner. Surfactant is periodically injected into the sump near the pump suction to ensure rapid and effective distribution throughout the system. Conductivity control rods are used to maintain liquid levels in the scrubber . They control a solenoid fill valve plus initial operation of the circulation pump to ensure the pump suction is flooded prior to energizing. The entire operation is controlled by a PLC package that initiates start up sequence, blow down cycle for the periodic removal of collected pollutants plus injection of surfactant after each blow down. Tied into these controls are contacts for the system fan, flow sensor on the circulation system and verification of flow for the surfactant injection system. Optional features such as hot water trays sprays, cold weather protection and VFD packages also become part of this controls package. The main control panel is mounted on the unit and factory wired to all the major components. A fan motor starter is also provided if a system fan is packaged with the scrubber. A remote control panel is also provided which is field wired between the main panel and this start/stop station. This remote panel has a manual key lock override switch to permit operating the system fan should the scrubber be shut down for a variety of operational problems. A chemical feed package is also included which consists of pump, surfactant storage container and plug connection to the remote control panel. An initial supply of surfactant is furnished by the manufacturer for initial startup. Most applications include a system fan that is mounted on the scrubber frame to provide a complete factory package. This fan is typically a direct drive BI design with TEFC motor, access door, housing drain and slide gate outlet damper for system balancing. Typical option includes spring isolators to eliminate vibrations and associated noises. Some applications demand the use of after filter sections, such as 95% DOP and carbon. These filter sections have side access panels with slide in/out tracks and typically add 30" length to the unit per section. The cold weather package option must be included when units are located outdoors or in non-heated rooms for locations subject to freezing temperatures. This package includes a complete enclosure of the equipment area with hinged access doors. The enclosure is insulated and has an electric enclosure heater with appropriate thermostatic control. There is a sump heater with thermostat to keep the water in the unit at 45 deg F. Because this enclosure can become hot during the summer months a screened intake and fan exhaust are also provided. When the unit is located outdoors in a warm climate an equipment enclosure is provided to protect the various components from the weather and sun. Build up on the scrubbing trays can reduce the effectiveness of the scrubbing action and reduce exhaust flow rates. This is a typical occurrence for systems handling vaporized animal fat. A hot water tray spray option is included in the unit for these applications which is controlled by the PLC. Typically the spray comes on once every hour for about 1 minute. This time can be altered to suit a specific situation. The unit PLC is preprogrammed for the interval between blow down, duration of blow down and
duration of surfactant injection. These times can be field adjusted to suit the actual operating situation to
optimize the consumption of water and surfactant. Note: during blow down cycle the fill valve is opened and
the water level rises above the sump end weir causing a small amount of water and collected pollutants to be
drained from the sump. Since some surfactant is also lost during this cycle the surfactant pump is energized
to inject a small amount of surfactant into the sump. This cycle is repeated as long as the unit is in
operation. HIT Scrubber Dimensions
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