Gala tempered water systems are an integral part of a pelletizing system. The TWS conveys and cools pellets from the pelletizer cutting chamber to the resin outlet of the centrifugal dryer. The TWS is a closed loop system.
The individual components relevant for the process are selected according to the specific application requirements. Gala’s tempered water systems are typically used in pelletizing process at rates up to 15.000 kg/h.
The MB500® Tempered Water System is a result of a cooperative effort between Gala and its Customers to develop a machine which directly addresses the need for the Custom Compounder to thoroughly clean the system between products. Small color masterbatch runs require frequent changeover. The MB500 targets this speciﬁc Customer need.
The process water system BF fulfils the following functions:
- Collecting of the process water and feeding it at the required pressure to the individual locations of consumption
- Cooling of the process water
- Separating dust and contaminations from the process waterProcess water systems BF can be retrofitted into existing pelletizing systems.
The process water treatment unit PWA serves for filtering, tempering, and circulating the process water in compound and masterbatch production and can be integrated into the base frame of the cooling trough or positioned externally. Using a heat exchanger, the PWA separates the contaminated process water circuit from the primary cooling circuit from the central water supply.
Gala’s IS (Integrated Sieve) Tempered Water System features a V-wire screen mounted directly under the dryer water outlet to ﬁlter solids from the process water prior to recirculation to the pelletizer. The screen is easy to remove for cleaning, reducing downtime between product changes. TWS 20 – 80 systems are skid mounted.
The Gala Continuous Band Filtration (CBF) is also designed as a retrofit for the pellet production line where there are fines created regularly on some products and operator attendance would normally be required to clean the IS drawer in the production frequently. After installation of the CBF, the operator does not have to monitor the system anymore. The advance of the filter media is continuous and does not need any activation in order to catch fines larger than 150 µm. The process water contamination is in most cases eliminated. The fines are continuously separated from the process water and collected in a mud cart.
The Gala Band Filtration System (BF) is designed for the pellet production line where there are several color changes throughout the day, and for the system used for cutting a product that creates fines resulting in contamination in the process water system. The operator do not have to monitor the system, the advance of the filter media is automatically activated in order to catch all fines down to 20 µm created before the process water becomes contaminated. In most of the cases, the water does not need to be replaced as it stays perfectly clean. The fines are continuously separated from the process water and collected in a mud cart.
The Gala FRS removes fine particles >0.15 mm from the process water. Clean process water prevents product contamination and the settling of fines in key system components. The curved screen and collection basin are made of stainless steel. A self-priming pump and internal piping may be used to convey process water from the dryer and over the curved screen. If the gradient is appropriate, gravity feeding will be sufficient. The process water contaminated with particles is first conducted into a holding chamber and then flows evenly over the curved screen. The fines >0.15 mm are separated and collected in a collection basin. The filtered water is recirculated.
The Gala DFRS removes particles down to 0.14 mm from the process water. Clean process water avoids the contamination of the product and the settling of fines in key system components.The entire volume of process water separated from the pellets in the centrifugal dryer is conveyed by a self-priming waste water pump to a vibrating screen where it is continuously filtered. The fines are automatically separated from the circulating water and collected in a container outside the water tank. The water dripping from the container is recycled into the process. By actuating a valve, the vibrating screen can be by-passed so the process water is conveyed directly into the tank.
The dual canister filter provides extra process water filtration in high production situations where shutdowns are kept to a minimum or when processing highly filled products that create fine particulates not caught by a standard fines removal screen. The dual canister filter assembly is located after the process water pump in the tempered water system. Its purpose is to filter any fine particulates that may not have been caught in the standard water system filtration screen. Most customers requesting this feature wish to eliminate unnecessary downtime for cleaning or for extra protection when pelletizing heavily filled products that cause fine dust. This system is typically used on pellet production lines running 250 gpm (60 m³/h) or greater. The system consists of two stainless steel cylindrical housings, each containing a screen basket with 100 – 200 micron mesh bag. Valves and piping complete the system, as well as appropriate electrical controls. This filtration system can be programmed for an alarm to sound for manual filter changing or, in most cases, fully automated changing from one filter to another. One canister is in operation while the second is being prepared or ready for use.