Multigrade Filters

The SEION industrial Multigrade Filters is a depth filter that makes use of coarse and fine media mixed together in fixed proportion. This arrangement produces a filter bed with adequate pore dimensions for retaining both large and small suspended particles.
This filter performs at a substantially higher specific flow rate than conventional filters. Specific flow rates of 15-30m/h have been successfully obtained for treating waters containing 50-25ppm suspended solids respectively to produce a filtrate with less than 5ppm.

Special Features :

  • Higher flow rate.
  • Raw water can be used for backwashing the filter.

Advantages :

  • Higher specific flow rate than conventional downflow filters thereby saving on space and cost.
  • Very little maintenance required.
  • Low backwash water requirement.
  • In most cases, raw water can be used for backwash.

Applications :

  • The SEION Multigrade Filter is an ideal choice for all applications where a conventional sand filter is used. It is extensively used in side stream filtration of cooling water and in portable water treatment. It is ideal for filtrations of clarified water. In addition it finds application in sea water filtration of chemical solutions. For these types of filtrations rubber lined or epoxy painted filters can be offered.
  • One vertical cylindrical mild steel pressure vessel with dished ends, painted internally with anticorrosive bitumastic paint and externally with a protective coat of red oxide primer.
  • One set of internal water distribution and collection system.
  • One initial charge of filter sand and under bed material.
  • One set of frontal pipe work and valves.
  • Two pressure gauges to monitor head loss across the filter.
  • Maximum/minimum operating pressure will be 3.5kg./cm and 2.0kg./cm respectively.
  • One orifice board (optional) for indicating wash water flow to be fitted in drain sump.
  • SEION Multigrade Filters are available from 600 to 3000mm diameters.
Unit Feed Water Suspended Solids
25PPM 50PPM
F-600

F-800

F-1000

F-1200

F-1400

F-1600

F-1800

F-2000

F-2200

F-2400

F-2600

F-2800

F-3000
8

15

23

33

46

60

76

94

113

135

159

184

211
4

7

12

16

23

30

38

47

56

67

79

92

105

Note :

  • Suitable coagulant should be used for effective filtration.