Air Washer Unit


Air Washer Unit

Usha Die Casting Industries (Industrial Equipment Division)" offers Well Engineered proven Designs and Constructions for Evaporative Cooling Wet Ventilation Systems / Air Washers. Humidification is rapidly gaining importance in many industries. The requirements of modern high-speed production techniques and increases in internal plant heat loads often result in the need for better control of humidity levels in the plant environment. Many industries face stringent indoor air quality standards. Meeting these standards can often require bringing more outside air into the plant. If this outside air is dry or cold the result can be much lower indoor humidity levels. We undertake Design, Supply, Erection and commissioning of Equipment and Project of Industrial Humidification and Ventilation systems on turnkey basis.

We can offer such Systems in Completely Modular & Pre Fabricated Constructions or in Civil Constructed Chambers with installed Modular System Components.
Operation of a Wet Ventilation System / Air Washer :-

The basic components of an Air Washer system is a chamber that contain a series of
  • Evaporative Cooling Pads with Top Water Spray System
  • An eliminator section that removes water from the air that is exiting the Air washer
  • Sump which catches both the sprinkled water droplets and the water that was collected by the eliminators.

The Evaporative Cooling Pad section will either add moisture to the air or dehumidify the air.

The eliminator section in many cases is a "W" or a series of "W"s in shape. This section, forces the air to contact the eliminator components, which in turn knocks down water droplets and air borne solids.

The sump is the collection basin for the system. The washed out solids, lint, dust, and water all collect in this area.
An air washer will humidify the air during the seasons when the outside air is low in humidity. This is usually during the Peak Summer / In arid climates. The reason that the air is humidified, is to create the proper condition for the operation of the plant. In the production of Textiles, Electronics, and other related industries, where the humidity of the air is crucial for the air quality and material production, the Air Washer will balance the required humidity of the plant air by humidifying the air during the dry seasons, and dehumidifying the air when the air conditions are more humid than the plant requires.

With evaporative cooling, a complete air change of the room takes place. This offers a great health advantage over traditional refrigerated air conditioning, which employs a complicated "closed" system that recirculates the same stale dry air over and over. Constant cool air movement pushes heat out -- along with stale air, smoke, odors and pollution. The high volume of fresh, cool air produced by the evaporative cooler helps your body ventilate naturally .Evaporative cooling helps maintain natural humidity level.

Generally our Evaporative Type Wet Ventilation Systems / Air Washers consists of following Components / Modules
PreFabricated Wet Ventilation Chamber / Civil Constructed Chamber as per Our DesignCentrifugal DIDW Fan / Axial Flow Fan
Inlet Bird ScreenDucting
Inlet Screen LouveresOutlet Louveres
Inlet MiroV Pre FiltersWater distribution system with Sump & Spray piping
Primary MicroV FiltersFasteners / Gaskets
Secondary MicroV Filters (Optional)Air Tight Doors
Evaporative Cooling PadsInstrumentation like Manometers / Hygrometers
Mist EliminatorsWet Bulb Thermometers

PreFabricated Wet Ventilation Chamber / Civil Constructed Chamber as per Our Design :-
PreFabricated Chamber is supplied in case of Space Limitations / Time Limitatons for Project Completion or on Specific Request from Customer. The Chamber is either completely fabricated or supplied in form of Panels for Site Assembly and Erection. In either case Heavy Gauge Steel is used with additional Double Coats of Red Oxide Primer and Two Coats of Epoxy Based Colour. In special cases chambers made of SS or lined with FRP are also supplied for long Life.

These are well fabricated to prevent any leakages after final assembly.

Civil Constructed Chambers are more suitable for Long Life and Sturdy Operation. These are usually built by Customer as per Designs / Drawings provided by us. These are generally large rooms having ample space for maintenance and other daily operational activities.

Inlet Bird Screen :-
Welded Wire Mesh Screens are provided either before Inlet Screening Louvers or before Inlet MicroV PreFilters. The Screen prevents Birds or any other unauthorized personnel to Tamper / Damage the Pre Filters or the System in General.

The screen is made in Steel Flat Panels and is very easy to mount in Bolted Design.

Inlet Screen Louveres :- Z Section Louvers are made in Modular Bolted Panels mounted just before MicroV PreFilters. These help protect the MicroV Prefilters from Atmospheric Dust / Rains / Direct Sunlight and any physical Tampering from Outside of System.

Louvers are made from Medium Gauge Steel and fabricated to be Light in weight to facilitate easy Installations.

Inlet MicroV PreFilters :-
Generally Inlet MicroV PreFilters are provided for screening large dust particles in the range of 50 Microns to 15 Microns depending upon applications.


The Inlet MicroVPrefilters are of HDPE Construction. These can be supplied in frames of different materials of constructions like MS / SS / Aluminum. All Filters come in standard sizes and interchangeable. Each filter is provided with Rubber Gaskets, Fasteners if required for Flange Types. Sliding type arrangements are also available. These filters are washable in case they get choked with dirt & dust.

Primary MicroV Filters :-
Generally Primary MicroV PreFilters are provided for screening dust particles in the range of 10 Microns to 5 Microns depending upon applications.

The Primary MicroVFilters are HDPE Construction. These can be supplied in frames of different materials of constructions like MS / SS / Aluminum. All Filters come in standard sizes and interchangeable. Each filter is provided with Rubber Gaskets, Fasteners if required for Flange Types. Sliding type arrangements are also available. These filters are washable in case they get choked with dirt & dust.


Secondary MicroV Filters :-
Generally Secondary MicroV Filters are provided for screening dust particles in the range of 3 Microns to 2 Microns depending upon applications. The use of these filters increases the Pressure Drop of the System causing more higher size selection & power consumption of Fan Equipment and thereby increasing the system capital cost and running cost.

The Secondary MicroVFilters are HDPE Construction. These can be supplied in frames of different materials of constructions like MS / SS / Aluminum. All Filters come in standard sizes and interchangeable. Each filter is provided with Rubber Gaskets, Fasteners if required for Flange Types. Sliding type arrangements are also available. These filters are washable in case they get choked with dirt & dust.

Evaporative Cooling Pads :-
The Evaporative Cooling Pad / Media is cellulose material impregnated with insoluble anti-rot salts and rigidify saturates. The material has spatial crossing linking technology with high absorb ability. It is water resistant, anti-mildew and has long service life.

Internal geometry of Cooling Pads is of transverse 45 degree and 15 degree alternating Flutes. The 45 degree flute carries the water to the Intake side of the media while the 15 degree flute is aligned with the direction of air flow. This flute arrangement is self-cleaning and increases cooling efficiency by causing air turbulence while air is traveling through the media.

The media must be installed in a proper orientation to the air flow. The 45 degree flute must be aligned upwards in the direction of the air flow (intake side of the flute must be lower than the discharge side) and the 15 degree flute must be aligned downwards with the air flow (intake side of the flute must be higher than the discharge side). If the media is aligned improperly, the water will flow to the discharge side of the media and can be easily entrained in the air flow.

Efficiency of Evaporative Cooling media is upto 90% at 2.5 m/sec face velocity for 300 mm Media depth.

Life expectancy is dependent upon many factors but is usually 3 to5 years when properly maintained and water pH is between 6 and 8.

Cooling Efficiency :-

Cooling efficiency is based on "Saturation Efficiency" (ability to transfer water vapor into the air stream). The two factors to be considered in determining the efficiency of the media are media thickness and air flow face velocity .

It is necessary to know the Dry Bulb Temperature and Wet Bulb Temperature entering the media to be able to apply the percent efficiency.

Mist Eliminators :-
These are provided after the Evaporative Cooling Media to entrain any carryover water droplets in the Air Stream.

The Eliminator section in many cases is a "W" or a series of "W"s in shape. This section, forces the air to contact the eliminator components, which in turn knocks down water droplets and air borne solids.

Centrifugal DIDW Fan / Axial Flow Fan Heavy Duty SYMBIOSIS Brand Centrifugal Double Inlet Double Width (DIDW) Fan / Axial Flow Tube Fan is provided as per requirements for Prefabricated Air Washers / Civil Constructed Air Washing systems.


The Fan shall be capable of delivering air volume at external static pressure as specified. For DIDW Fan the discharge mode shall be down, side or up as specified. The fan shall have a solid, ground and polished steel shaft with a lubricate self-aligning type bearing on each end.

Motor shall be Totally Enclosed Fan Cooled (TEFC) type as specified and sized to drive the fan at specified capacity without exceeding nameplate rating. Electrical characteristics of the motor shall comply with available electrical services as specified. Motor mount shall be adjustable to allow for drive belt tension and alignment.

Vibration isolation shall be provided under the fan and motor. Isolators shall be selected for minimum deflection. Flexible connector shall be attached between the fan discharge and the cabinet.

DIDW fan is generally provided in MS construction. The Impeller and casing are coated with Double coat Epoxy paint for long life or on specific request from customer FRP Lined for corrosion resistance. SS 304 Casing and Impeller can also be provided as per customer requirements and applications.

Axial Flow Fan tube is coated with Double coat Epoxy paint for long life or on specific request from customer FRP Lined for corrosion resistance. SS 304 Casing and Impeller can also be provided as per customer requirements and applications.

Axial Flow Fan Blades are Cast Aluminum and Bolted to central Hub. This facilitates easy removal / maintenance of Impeller. DIDW Centrifugal Fan Impeller & Axial Flow fan blade is dynamically balanced on computerized balancing machine to give trouble free & smooth running performance.


Ducting :-
Outlet Delivery ducting is provided after the discharge end of the Air Washer chamber for air distribution inside the room. As per customer requirements this ducting can be made in materials like GI / MS / SS.

Outlet Louvers :-
Outlet Louvers are provided at Discharge end of the Duct for proper throw of Air at required position in the room. These louvers can be provided as fixed or adjustable type as per customer requirements.

Water distribution system with Sump & Spray piping :-
Stainless Steel couplings with female pipe thread shall be welded into the sump and side to provide for make-up water, overflow and drain.

Water distribution system shall be Pump re-circulating system with Mechanical float valve assembly to maintain water level in the Sump. Pump horsepower and voltage requirements shall be as specified by customer. A bleed-off system with metering valve,if required, shall be provided when the pump system is used. Bleed-off rate shall be minimum of 21% of evaporation rate. Pump shall be sized to deliver water flow rate at the head and pressure required. Flow rate shall be determined at three (3) times the evaporation rate plus the bleed-off rate. Pump will be Monoblock type standard with impeller MOC as per customer specifications.

Internal plumbing shall be PVC or SS 304 Schedule 40 sized to meet flow rate demand unless otherwise specified. A Balancing valve shall be provided in the riser pipe between the source and header to regulate water flow over the media. Header pipe shall contain drilled and cleaned orifice holes sized to assure proper water flow over the Media. Water from the header pipe shall be discharged upwards against a stainless steel deflector to redirect the water from the header pipe back onto the media, evenly across its' full width. A union shall be provided in the riser pipe below the header pipe to facilitate removal of the header pipe.

Fasteners / Gaskets :-
All fasteners shall be SS or GI for all bolted joints. Gaskets shall be of Asbestos or Neoprene Rubber type as per specific request from customer.

Air Tight Doors :-
All access doors to the prefabricated chamber / civil constructed chamber shall be Air Tight with proper gasket sealing and locking system. The doors shall be sized adequate for movement of manpower , miscellenous tools tackles, cooling media, piping material for regular maintenance work.

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