2 sand and gravel automatic backwash filters, 3 centri-separator filter systems – Sterling FILTRATION AND SEPARATION SYSTEMS SGM-250A User Manual
Page 6

Page 6
Water Management Systems and Products
1-2 Sand and Gravel Automatic Backwash Filters
Sterling/Sterlco sand and gravel filters are shipped complete with:
• Tank 
• Valve manifold 
• Gauges 
• Initial charge of sand and gravel 
The system switches valves automatically. Two backwash control 
mechanisms are available. Backwash cycles can be based on a time 
cycle (SGM-250A) or pressure differential across the unit (SGM-
250P). 
SGM-250A sand and gravel automatic backwash filters are 
available in a 250-ton (756,000 Kcal/hr) model for cooling towers 
and a maximum-capacity 500-ton (1,512,000 Kcal/hr) chiller 
model. The SGM250A model is equipped with automatic valves 
operated from a timing device so that the backwash cycle 
automatically activates on a periodic basis. 
Filters must be installed in a bypass line so that plugging of the 
filter or temporary shutdown required for back washing does not 
hinder process operation. 
1-3 Centri-Separator Filter Systems
Sterling/Sterlco centrifugal separation systems are used on cooling 
tower or chilled water systems requiring large capacity, heavy-duty 
suspended solids removal. 
The Centri-Separator System (CSM-150) is designed to handle up 
to 150-ton (567,000 Kcal/hr) cooling tower systems and up to 300-
ton (907,200 Kcal/hr) chiller systems. The CSM-150 includes a 
centrifugal separator, 
1
/
3
hp (0.25 kW) pump,
1
/
2
” PVC electrically-
activated ball valve, and a 115 volt single-phase 60 hertz control 
station. The CSM-150 can be mounted on a pump tank or piped in 
a bypass line. The system performs all operations, including 
separator purging, automatically. 
 
The CSM-400 is designed for larger tower water system 
applications; up to 400-ton (1,512,000 Kcal/hr) cooling tower 
systems and up to 800-ton (2,419,200 Kcal/hr) chiller systems. 
