The SDI 2200 (Silt Density Index) is a full automatic, multi channels on line analyzers and monitoring systems.
The SDI 2200 is a unique analyzer and designed for continuous, unattended operation in desalination and other water treatment plants.


  • Fully complies with the ASTM D4189-07
  • CE certified
  • Up to 4 sampling points
  • Up to 85 cycles (to complete one paper filter roll) without operator interference
  • Several modes for operation and calculation per channel 
  • Three built-in operational modes:
    1. 1.Manual (one-cycle only)
    2.  Auto (programmable time interval)
    3. 3. Remote (pre-started selected channel from remote station)
  • Two built-in calculation formula can program per channel:
    1. Standard mode test for low SDI water (less than 5.0 for 15minutes)
    2. Auto Time mode test for HIGH SDI water (greater than 5.0 for 15 minutes)
         * Measure time 1-15 minutes 


Principal of operation

Standard Test Mode

Silt Density Index (SDI) is measured by comparing the flow rate of a known volume of water, where the water volume is kept under constant pressure. 

The flow rate is measured twice; first time is when the water flows for reference through a standard unused filter, second time is after the filter is exposed for 15 min. or less. 

The water sample flow is always kept under constant pressure. The drop in flow rate is a direct measure of the silt build-up on the filter.

The pressure is kept constant by precisely regulating air pressure applied on the water surface without the need of any mechanical device


Auto Time Test Mode
In cases where the silt density index (SDI) reading is unstable and readings are higher than 5 (i.e. Plugging Factor is higher than 75%), during the 15 minutes check time, the analyzer can be programmed to work in Auto Time Test Mode based on the following test method:

  • The plugging factor calculations will proceed and will be recorded at intervals of one-minute elapsed
  • Calculations will stop once plugging factor 75% has been reached
  • New SDI readings will be displayed based on the last calculated factor
  • The exact check time has no valuable meaning (as in Standard Test Mode)
  • In general, the higher the SDI reading the more silt is in the water.
When plugging factor is calculated to be lower than 75%, the analyzer will switch and calculate the test results based on the Standard Method.

System types

The SDI format definition: SDI 220 N-A-E-T

N number of channels (1-4)
A number of analog outputs (1-4)
E Ethernet communication
T temperature measurement


  • Optional analog output (programmable range) per channel for remote control and monitoring purposes
  • Booster pump - When supply is in low pressure, one booster pump support all channels
  • Temperature measurement and compensation (if necessary)


  Height Width Depth
Cabinet Wall mounted    1,126 mm    525 mm    310 mm   


Utilities needed

Input pressure            35 – 80 psi
Flow rate                   11/2 l/min. 
Air pressure                80 – 120 psi
Electrical                   110 – 230 VAC at 4 Amp. Or 24 VDC

Filter paper type

Standard Millipore    0.45 micron roll paper 
Length of roll           6 meters, up to 85 measurements per roll 

Control System                            Communication

  • CPU                                
  • Color touch screen
  • RS488
  • RS232


Uptime                    >99.9%
Repeatability           less than 0.1 SDI units
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