ISO 9001

DH TECH Co., Ltd.Tel : +82-51-314-3321 http://www.dh3321.com

D.H. Tech (Dae Hwa Tech),A professional manufacturer of cooling tower

Water treatment systems in the 21st century.

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Contents

A. JOBSITE INSTALLATION TYPEB. FACTORY ASSEMBLY TYPE (GREEN SERIES)

1. ROUND TYPE (DHG-RO)2. CROSS TYPE (DHG-CR)3. COUNTER TYPE (DHG-CU)

1. WASTE WATER TREATMENT SYSTEM2. COOLING WATER SYSTEM3. PRETREATMENT SYSTEM4. DEMINERALIZED WATER SYSTEM

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It has been long that water, which had been affluent all the time, became an important resource. And it is true that water is a cause for the disputes for rights among nations and it has big influence on companies costs for production. Based on the business ideology of customer-centered quality management, we, D.H. Tech, regard customers important and try to render services to them. With the attitude of continuously changing and making efforts, all of our executives and staff produce and supply various models of products covering environment-friendly industrial/air-conditioning cooling towers and closed circuit type cooling towers with special specifications that can prevent white smoke and minimize any loss of drift. All the engineers of our new technical development research institute are doing our best to meet with customers needs.

Not satisfied with the current outcome, we produce water treatment systems, chemical dosing systems, and peripheral systems for water treatment which are directly related with the cooling tower systems, through which we stretch ourselves to a new leader specialized in the environment of the 21st century. Our cooling circulation water systems and cooling towers of low noise and high efficiency are working for local prominent companies including POSCO and overseas jobsites, dynamically contributing to the development of industries. We will do our best to open a new horizon of the environment industry based on the development of new technologies and the reliable management. We will always carefully listen to customersexcellent opinions so we will go forward.

HISTORY

1993 011999 031999 072000 01

2000 022000 022000 03

2000 042000 042000 052000 052000 052000 052000 062001 07

2001 082001 102001 112002 012002 012002 052003 022003 022004 022004 092004 122005 022005 02

2005 032005 04

2005 122006 05

2006 10

2006 102006 122007 022007 042007 112008 022008 022008 10

2009 02

3DH TECH Co., Ltd

>>Founded Dae Hwa Plant Incorporated under the name of D.H. Tech (Dae Hwa Tech)Be selected as a supplier for POSCO Be selected as a supplier for POSCO Engineering & Construction (cooling tower B grade) Had a groundbreaking ceremony for a new factory at Gamjeon-dong Registered the design of cooling tower filler (Ref. No. 0256243)Be selected as the consortium for industry-academic research cooperation(Dong-Eui University) Registered the new device of a cooling tower (Ref. No. 0185436)Acquired ISO 9001 certification (Ref. No. QSC02608)Completed to construct the factory at Gamjeon-dong Moved the head office to 127-4, Gamjeon-dong, Sasang-guRegistered the factory (Ref. No. 8-149)Registered the trademark (Ref. No. 04070474)Registered the trading business (Ref. No. 12122530)Be registered as a supplier for POSCO Engineering & Construction(water treatment system B grade) Opened Youngnam and Honam Office for Baltimore cooling tower (Ref. No. 91)Constructed ERP I.T. of Small and Medium Business AdministrationBe selected as a promising small business by Busan Bank (Ref. No. 2001159)Registered the new device (Ref. No. 0262285)Registered the new device (Ref. No. 0263031)Be certified to record 1-time no accident (Ref. No. 02-81-0017)Be selected as an excellent company by POSCO Engineering & Construction Attained 3-time no accident Attained 3-time no accident Founded a corporation in Qingdao, China Be selected as a clean workplace (Korea Occupational Safety & Health Agency)Attained 4-time no accident Applied for a new device (Ref. No. 20-2005-005586)-Backwash remaining float collector for water treatment sand filter Be selected as 2005 good-quality supplier by POSCO Engineering and Construction Registered the preventive system business (Ref. No. Shore Protection Division -Water-38)-Type of the preventive system business: Water quality (Busan) Joined Cooling Technology Institute (CTI) Registered the construction business (mechanical system construction) with Sasang-gu, BusanMade a contract for a new factory site in Hwajeon Industrial Complex (the whole area of Shinho and Hwajeon-dong, 2,975.30m)Acquired the approval of the foundation of a research institute for the company Be registered as a member of Korea Industrial Technology Association Attained 6-time no accident Be selected as 2007 good-quality supplier by POSCO Engineering & Construction Be certified as (INNO-BIZ)Attained 7-time no accident Be designated as a prospective exporter Best Company in 2008 significantly improved the quality certificate Korea (Seoul Economic Daily)Achieve Not a disaster 8 times

Cooling Principle of Cooling Tower

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Cooling Tower

The heat, which is generated from a freezer and production processes, is sent to cooling water through a water cooling heat exchanger, and the heated cooling water is sent to a cooling tower through a cooling water circulation pump. This water is cooled at the temperature required by the freezer and the production processes, and then, is sent to the water cooling heat exchanger again. In order to remove the heat of cooling water, the fan on the top of the cooling tower induces the air in the optimum status through the air intake at the bottom of the cooling tower and then, inhales it into the cooling tower. And then, it vertically increases it evenly on the whole filler. The cooling water that has heat load passes through the cooling water inlet, goes through the water distribution system, is sprayed evenly on the top front of the filler from the injection nozzle, and vertically flows down along the trough of the filler by gravity. At this time, the air and the cooling water meet so heat is transferred due to the evaporation latent heat and the temperature difference between the air and the water, which makes the water cool.Counter-type cooling tower removes heat from cooling water like this: when cooling water is sprayed from the injection nozzle of the water distribution system, about 5~10% gets cooled and 80~90% of the total required heat removal is cooled in the filler; and the remaining heat is removed when the water passes through the filler, arrives at the lower basin, and crosses the cold air that is inhaled into the cooling tower.The rate of heat removal by the evaporation latent heat is different, depending on the dry bulb temperature of the air, the relative humidity, and the cooling range, which amounts to about 60~90%. The higher the dry bulb temperature is and the lower the relative humidity is, the higher the heat removal rate by evaporation is. The cooling tower that is opposed to the dry cooling tower and that transfers heat through the direct contact between the cooling water and the air is called an evaporation type cooling tower. The loss of cooling water caused by evaporation is inevitable so through a makeup water system, the loss should be supplemented.

Composition of Cooling Tower

Cooling Water Outlet

Inspection Door

Casing

Cooling Water Inlet

Fan Cylinder

MotorBelt Driving Device

Axial Fan Cooling Water Inlet

Injection Nozzle

Filler

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CORROSION RESISTANCE

EASY MAINTENANCE Prefabricated construction will be the most convenient to maintain the system

ANTI-WATER DRIFT LOSS Excellent eliminator will prevent from any water drift loss

LOW NOISE OPERATIONNewly developed V-belt double reducer or geared double reducer and FRP fan will give water scattering to the outside of tower.

HIGH PERFORMANCE OF WATER-SPRAYING

Low pressure in upper water tank (piping) gives excellent distribution of water spraying.

RECTIFICATION TYPE LOUVERUtilizing rectification system increases the efficiency of filling and also prevents any water scattering to the outside of Tower.

BIG CAPACITY OF COLD WATER BASIN

Big sized cold water basin equipped with drain and filling system will prevent any air inflow in pipe lines.

COMPACT FRP CYLINDER

Specially designed Dae Hwa Tech Co., Ltd. bell mouth type FRP cylinder guarantees high preformance.

The Kinds of frame are metal, RF CONC and DOUGLAS FIR. Which is treated to preserve from decay with ACQ and all metal frames are coated with zinc alloy and casting is composed of zinc coated plate or CACB combinated With FRP These features will give you high resistance of corrosion and guarantee high durability.

INDUSTRIAL TYPE COOLING TOWER

DH TECH Co., Ltd

Structures and

CharacteristicsPerfect refrigeration effect to meet purchasers' needs

BODY

EXCELLENT SPRINKLER DESIGN ANDREDUCTION IN AUTOMATIC FEED WATER

The sprinkler rotates automatically with the low pressure of thecirculating cooling water jet spray. So that it can reduce the automatic water.

GOOD PERFORMANCEThe proper designs provide the good ventilation and wide contact area between liquid and vapor.

CORROSION RESISTANCEThe main parts are made of FRP, plastics, and other metallic parts are hot dip galvanize plated, which can give Good Corrosion resistance and good durability.

LOW CONDUCTIVITYFRP body has low conductivity of the solar heat, correspondingto about 1/300 of metal, so that it can maintain the high cooling efficiency

LOW NOISEThe fan is the axial flow type developed by the Dae Hwa Tech Co., Ltd. To generate much airflow with low noise. It is Made Of FRP in most models.

The body is made of FRP which has the graceful figure. It is firmly assembled to from the bell-mouth shape, so That it can reduce the pressure loss.

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GREEN TYPE COOLING TOWER (DHG-RO)

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Round Type(DHG-RO)

Planned manufacturing based on smaller-size, lighter-weight, and standardized plan

MINIMIZATION AND LIGHTWEIGHTOF INSTALLATION SPACE

ENERGY SAVINGThe power of fan is reduced by smoothing air flow due to bell mouth-shaped fan stack and energy is saved, using packing materials with less pressure loss.

CORROSION RESISTANCE

It has made been semi-permanent by using PP and PVC not to corrode, water to touch all parts within cooling tower, and made corrosion resistant FRP for hot water basin, cold water basin and casing

BUILT-UP TYPE AND FINISHED PRODUCT

The cooling tower shall be manufactured, assembled and installed in the factory at same time, so it has good quality due to simple and rapid installation. The kind under 500R/T cannot need assembling process

PROTECT AGAINST NOISE POLLUTION DUE TO LOW NOISE TYPE

CHEAP PRICE AND EASY TO MAINTERNANCE

Installation space is reduced and operation weight is minimized,using high effceincy packing materials specially designed for cooling tower of vertically alternating current.

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GREEN TYPE COOLING TOWER (DHG-CR)

DH TECH Co., Ltd

Cross Type(DHG-CR)

Planned manufacturing based on low-noise, low-arsenic acid, and standardized plan

FILLER OF HIGH EFFICIENCY

THE DUPLEX DISTRIBUTIONSYSTEM

We improved the efficiency of heat exchange by jetting out the cooling water sufficiently through the SPRIAL TARGET NOZZLE and the DISTRIBUTION EQUIPMENT which is added at the top of the filler.

WIDE AIR TRAVEL The width of filler was made longer.

THE PROFITABLE DESIGN OF AIR FLOW

Optimum arrangement in fan and filler removed DEAD SPACE of air flow and promoted the efficiency

FAN OF HIGH EFFICIENCY

The weak point which the cooling water leaned to one side is removed by the air velocity which is sucked and the heat exchange efficiency is maximized. The interval maintenance method of filler was especially designed and the air resistant minimized.

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WE ADOPT FRP AXIAL BLADE OF HIGH EFFICIENCY

THE EQUIPPED HOOD ON THE TOP OF THE FAN STACK CHECKEDJ A SCATTER AND REDUCED A NOSIE

CASING AND WATER BASIN DECRESE WEIGHT USING THE QUALITY OF MATERIAL. CORROSION OF STRUCTURE IS PROTECTED BY HOT DIP GALANZING

IT HAS NICE LOOK FOR HARMONIZE WITH ANY PLACE

GREEN TYPE COOLING TOWER (DHG-CU)

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Counter Type(DHG-CU)

Planned manufacturing based on low-noise, low-arsenic acid, and standardized plan

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The motor of the cooling tower is totally closed and designed to make high efficiency. Based on Customers requirement, a pole change type or an inverter type is supplied. The reducer and the shaft are designed suitably for the horse power and the RPM of fan speed. It is special waterproof-treated so it can stand long-term consecutive driving under high temperature and humidity.

DRIVE PART

The V-belt reducer for the cooling tower is used for less than 3600 fan diameter and low hp. Its manufacture and installation are simple, and it is easy to repair and maintain.

V-BELT REDUCER PART

It has neat appearance and close blade tip clearance, through which it improves the performance of thecooling tower. 1,200~10,000 are available and it is made of FRP, steel plate, or wood.

FAN STACK

Main structure of cooling tower

Industrial Type Cooling TowerCharacteristics of Components

DH TECH Co., Ltd

The filler makes the heat transfer area of water and air and the heat exchange time large. A splash type and a film type are available. Wood, PP, PVC, or HIPS, which is heat-resistant enough to stand hot water, is used.

FILLER PART

It is made of concrete, FRP, wood, or steel plate. The nozzle which is suitable for various PIPPs is selected to evenly spray water. By having no dead space, it improves the cooling capacity.

DISTRIBUTION PART

Main structure of cooling tower

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Eliminator, which prevents the loss of water caused by scattering and evaporation, is made of PP, PVC, HIPS, or wood. Depending on the type of the cooling tower, other material, whichis excellent at heat resistance and acidityremoval and has long lifetime, can be used.

ELIMINATOR PART

It is designed to determine the direction of air flow and to increase the cooling effect. FRP or aluminum is used.

FAN

Industrial Type Cooling TowerCharacteristics of Components

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OVERVIEW OF WASTE WATER TREATMENT SYSTEM

This system is for harmful waste water coming from industrial jobsites of dyeing, plating, and leather. It physically, chemically, and biologically treats pollutants, such as organic/inorganic matters and heavy metals. Organically using the nitrogen removal technique, it fundamentally blocks the discharge of pollutants.

SEDIMENTATION TANKIt chemically treats polluted water, naturally precipitates, andisolates. These days, a high-speed condensation and precipitation apparatus is used that each work of mixing, condensation, and precipitation is performed in a sedimentation tank.

AERATION TANKIt makes microorganisms purify water through oxidation, which uses activated sludge process, and through digestion by aerobic bacteria.

SLUDGE STORAGE TANKIt reduces the percentage of water content of the sludge which is generated in the process of treatment, and increases the concentration of suspended solids. Through this, it reduces the volume of raw sludge and at the same time, it makes it harmless.This is for the safe and prompt treatment of sludge.

FILTER PRESSIt evenly mixes sludge which comes from industrial jobsites withpolymer and then, discharges out sludge floc in the form of plate shaped-cake through a dehydrator. It is a dehydrating system that consecutively treats large quantity.

FLOW-SHEET

Waste Water Treatment System

DH TECH Co., Ltd

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OVERVIEW OF COOLING WATER SYSTEM

This system is to supply cooling water to heat loading systems, such as steel manufacturing and power generating facilities. Using the technologies of precipitation, filtering, isolation, and cooling, it cools down hot water and re-circulates. Open and closed circuit types are available.

COOLING TOWERIt cools down the process water of high heat that is generated from industrial processes, and then, uses it again.

SCALE PITIt precipitates, separates, and removes floats and suspended solids included into the industrial water that isgenerated from industrial processes.

SAND FILTERIt secondarily treats the process water that is primarily precipitated and separated in the scale pit. It filters Minute floats and suspended solids.

FLOW-SHEET

Cooling Water System

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OVERVIEW OF PRETREATMENT SYSTEM

It isolates turbidity, chromaticity, mud, SS, and organic/inorganic matters from the surface water collected from a river or a lake, using the gravity-sedimentation technique. It filters the water and produces industrial water. This is the raw water purification system. It induces raw water into the clarifier and then, oxidizes and removes N-S compound COD. In addition, it oxides, dissolves, and reacts N-S compounds with NaNO2, and then, removes Cz2+, dissolved heavy metals, and SS at the same time. In addition, by injecting polymer, it helps effective precipitation. At this time, fluorine, which is made as floc, and heavy metal compounds are isolated with gravity. The sludge which is precipitated at the bottom is moved to the thickener to be concentrated. And some of it is re-circulated at the bottom of the clarifier, which prevents sludge stopping. It passes through the COD removal process, maintains ph at neutral, and then, re-produces industrial water.

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GRAVITY FILTERGravity filter filters raw water, which is primarily filtered byA clarifier, by use of the gravity-sedimentation technique.

CLARIFIERIt induces raw water, which has passed through the reaction and the neutralization step, condenses, and isolates primary organic and inorganic matters.

CHEMICAL TANKThis is for chemical injection by step that is necessary for chemical treatment with ALUM, NaOH, or polymer.

FLOW-SHEET

Pretreatment System

DH TECH Co., Ltd

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OVERVIEW OF FILTERING SYSTEM

It is composed of a sand filter and an activated carbon filtering system, which is operated unmanned automatically by gravity and pressure.

PRINCIPLE OF ACTIVATED CARBON FILTERActivated carbon is obtained by activating carbon-containing materials. It is an amorphous carbon aggregate composed of numerous minute pores (10~100,000) and very wide surface area (500~1500m2/g). Therefore, when the size of the minute pores and the surface area are big, it has high absorptive power. It is non-polar and physically and oxidatively very stable so it is extensively used for the purposes of discoloration, deodorization,collection, seperation, assembly, and refining.

FLOW-SHEET

Filtering System

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USAGE OF FILTERING SYSTEM

Absorption of organic matters Absorption and removal of colloids which cant be removed by a filter

Removal of BOD and COD Removal of remaining chlorine and ozone Removal of organic compounds, such as ABS and phenol Deodorization and decoloration

SAND FILTER ACTIVATED CARBON FILTER

15DH TECH Co., Ltd

OVERVIEW OF DEMINERALIZED WATER SYSTEM

It removes cations, anions, and particular harmful materials from a solution, using ion exchange resin.It is used for softening water, removing iron and manganese, and making pure water. With RO and MF system added, it can make Ultra-pure water.

REVERSE OSMOSIS SYSTEMReverse osmosis reversely uses a semipermeable membrane of the osmosis phenomena in nature. It is effective for 99% removing minerals/ionized inorganic matters/numerous impurities/ bacteria/germs which are contained in water a lot, SS which polluted underground water contains, rust stain and iron in waterworks, and secondary compounds in some waterworks flown from industrial waste water (300 molecular weight or more). It is used for the pretreatment of ultra-pure water for semiconductors, and it is extensively applied to various water purification treatments (i.e., changing sea water into fresh water).

MIXED BED ION EXCHANGE SYSTEMThis system is to make pure water by filling strong acid positive ion exchange resin and strong basic negative ion exchange resin in a single tower, and passing raw water through it. In case the raw water contains a lot of salts, it is effective to pre-treat it with strong acid positive ion exchange resin tower and weak basic negative ion exchange tower. Compared with the twin bed ion exchange system, this system can keep stable water quality against the changes in the quality of the given raw water and the velocity of a fluid.

TWIN BED ION EXCHANGE SYSTEMThis system makes pure water by passing raw water through the strong acid positive ion exchange resin tower to remove positive ion, and by passing it through the strong basic negative ion exchange resin tower to remove negative ion. It is desirable to reduce negative ion load by removing carbon dioxide through the degasfier installed on the front of the negative ion exchange tower. It is recommended to make the size of the negative ion exchange tower small to reduce the consumption of NaOh (recycling agent).

FLOW-SHEET

Demineralized Water System

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DH TECH Co., Ltd.Tel : +82-51-314-3321 http://www.dh3321.com