Water & Wastewater Asia Jul/Aug 2018

WATER & WASTEWATER ASIA July / August 2018 INSIGHT / 51 Filter Feeders A technology that is growing in acceptance for use in chemical introduction to boiler water –with an added bonus of filtration capabilities – is the filter feeder for use in low- pressure gravity or pump return- type steam-heating systems. The filter feeder combines the ability to inject various water-treatment chemicals with the capability to perform high-capacity filtering of the rust, corrosion, scale and coagulated solids into one piece of equipment, killing two birds with one stone. An advantage is the use of a filter bag that has the ability to protect against harmful particles and debris by trapping almost all contaminants rather than relying on inefficient and unreliable strainers or dirt/air separators. While 60- to 90- mesh screens can intercept larger particles, today’s filter bags can capture impurities as small as one micron, or five times smaller than the width of a human hair. Another benefit of the filter bag is that it can be removed from the filter feeder and thrown away when full, ensuring that all captured solid particles will be disposed and not be reintroduced into the boiler system. Filter feeders are ultimately a convenient and reliable way to introduce solid or liquid chemicals into the boiler while at the same time filtering out any rust, scale or other contaminants that may compromise the overall performance of the boiler, or any of its sensitive internal components. Conclusion Boilers are an undeniable necessity in heat production for many different types of buildings, or power generation to provide light for them. The boiler can only perform effectively if the water used to generate steam does not contain some type or level of impurities, deeming it imperative to treat the water with chemicals with the proper doses and feed rates, in order to make it safe for use. Operators of boiler systems are finding many options, with hydraulic and solenoid pumps, along with filter feeders, moving to the fore as a technology of choice in crucial chemical-injection applications. WWA About the author Tom O’Donnell is Director of Business Development for Neptune™Chemical Pump Company and PSG ® . The Solenoid Metering Pump Skid