UPW Pressure Vessels


PACT pressure vessels are pre-engineered or custom designed for manual or automatic operation. PACT 's in-house manufacturing facilities provide sand/grit blasting, priming, painting and rubber lining. The pressure vessels are manufactured by technicians specialized in all disciplines of steel and alloy steel handling, forming, metal surface preparation and welding. All apparatus are available at PACT 's manufacturing facilities for nondestructive testing, x-ray inspection, high voltage electric spark lining integrity testing, etc. Standard tanks are designed for working pressure of 7 kg/cm 2 and fabricated to ASME section VIII specifications.


PACT pressure filters are used for a variety of applications and most commonly for filtration of particulates at a slow rate (sand filters), deep filtration at a higher rate (multi-media filters) and adsorption of chlorine/taste/odor and removal of organics (carbon filters).


Hard water contains dissolved minerals in the form of Ca ++ and Mg ++ . Removal of these minerals is accomplished by softening the water through an ion-exchange process. The medium used is a strong acid (cation) resin in the sodium form with a very high bead count. The PACT ion-exchange resin combines high operating capacity with excellent chemical/physical stability. The regeneration cycle can be initiated manually or automatically by a day time clock or a water meter.


Employing cation and anion resins in separate vessels, these units are capable of producing water of low mineral content. The mineral content present in the effluent of the anion consists primarily of trace sodium ion. In conjunction with hydroxyl ions the effluent will have a pH range of 8.5-9.5. There are two types of anion resins each with a different function. One type is weak-base and the other strong-base. Strong base resins react with all minerals removing weak acids such as silica and CO2 . Caustic soda is used to regenerate, often at elevated temperatures when low silica leakage is demanded. Weak- base resins have higher operating capacity than strong-base resins and function only at low pH. They cannot remove silica and CO2 . These resins are generated with caustic soda, soda ash or ammonia. The choice between the two depends upon the purity requirements. Weak-base two-bed units typically produce water with 3-5 ppm residual minerals, excluding silica and CO2 . On the other hand strong-base two-bed units treat the water to a level of ionized solids below 3 ppm including silica and CO2 .


Mixed-Bed deionizers have a proven record as primary equipment to provide extremely high purity water for process use such as semiconductor, electronics, power and similar critical applications. Mixed-bed units employ cation and anion resins in a single vessel. These units produce water of neutral pH and ultra low mineral content of total ionizable solids in the ppb range. They may be used as stand alone units or as polishers downstream of a two-bed deionizer or a reverse osmosis system.