A filter for cooling systems using low-quality water ALF – Alfa Laval Filter The use of inexpensive secondary cooling water has become a widely accepted and successful solution to cooling problems within industry, on ships, in power plants and in district heating and cooling systems. However, as the supply of good quality cooling water has diminished, the need for cost-efficient solutions to eliminate clogging, fouling and corrosion has become more apparent. In a cooling system incorporating a plate heat exchanger and an Alfa Laval Filter, polluted or corrosive water can now cool even the most sensitive process equipment. The Alfa Laval Filter operates as an integral part of a cooling system to remove debris which can foul and clog a plate heat exchanger or a tubular condenser. The Alfa Laval Filter is also well suited for use with many process liquids for which filtration is required. In spite of effective screening at the water intake, mussels and other forms of marine life can get into the heat exchanger and settle on the heat transfer surface. Such conditions are ideal for the growth of these forms of life and they multiply rapidly, causing reduced heat transfer and even breakdown of the heat exchangers. Measures such as backflushing and chlorination are not always sufficient if the blockage is severe, and in some cases, chlorination is prohibited by environmental legislation. The Alfa Laval Filter protects the heat exchanger from clogging and fouling and also prevents blockages in the cooling water system. This filter, which is generally installed close to the heat exchanger inlet, removes debris and marine life and is automatically backflushed at regular intervals.

Operation and design ALF is a pressure filter with an automatic flushing arrangement. It has a filter casing made of stainless steel (ALF-S), fibreglass reinforced polyester (ALF-P) or rubber lined carbon steel (ALF-R). The internal cylindrical filter basket is made of stainless steel. Optional filter basket material qualities and mesh sizes can be selected. The filter is available for connections ranging from 100 mm / 4" to 600 mm / 24" and is designed for placement directly in the pipe system. This enables installation of the filter in almost any position. ALF has the inlet directly in line...

Installation All of the ALF models are suitable for protecting heat exchangers from clogging. In this case, no valve is required between the filter and the heat exchanger and the flushing outlet can be connected to the heat exchanger outlet. The ALF can also be used with one filter serving a battery of heat exchangers. This manner of operation requires the filter to be placed in close proximity to the heat exchangers with no dead ends or low velocity sections. This installation arrangement is generally combined with a bypass around the filter. Advantages ALF solves most fouling problems in natural...

88 132 220 440 880 1320 2200 4400 8800 22000 44000 psi bar 4,35 0,3 7,25 0,5 0,435 0,03 0,145 0,01 m3/h US gpm kPa How to contact Alfa Laval Contact details for all countries are continually updated on our website. Please visit www.alfalaval.com to access the information direct. PEE00007EN 0312 Alfa Laval reserves the right to change specifications without prior notification. Fig. 5 Alfa Laval Filters in closed loop cooling system protecting plate heat exchangers Fig. 3 Recommended pressure drop and capacity range Fig. 4 ALF20-S with electrical actuators and optional pressure transducers for...