Manual SDI15 Analyzer

Manual SDI15 Analyzer

>>Features‌‌

① ‌Lightweight and low-cost‌, yet durable and long-lasting
② ‌Stainless steel composite filter‌ offers high flow rate and maintains shape under pressure
③ ‌Built-in air vent valve‌ eliminates the need for manual adjustment
④ ‌Quick-connect fittings‌ on all joints for easy assembly and disassembly
⑤ ‌High-quality filter membrane‌ ensures accurate and reliable testing
⑥ ‌Complies with ASTM D4189-23 standard

>>Technical Parameter

>>Technical Parameter

SDI is a measurement of the pollution level determined by the amount of flow through a 47mm, 0.45um microporous filter membrane in a filter holder over 15 minutes, while maintaining a constant feed water pressure of 30 psi into the filter. Flow rates are measured at the start of the test (t=0) and at 5, 10, and 15 minutes. The maximum possible SDI 5 value is equivalent to 100% divided by 5 minutes (or 20 SDI units per minute of plugging percentage). The maximum possible SDI 10 value is equivalent to 100% divided by 10 minutes (or 10 SDI units). The maximum possible SDI 15 value is equivalent to 100% divided by 15 minutes (or 6.7 SDI units).‌

‌If 100% plugging occurs during the 15-minute test:‌ Stop the test and calculate as follows.
(100% plugging is defined as the continuous water stream breaking into drops)
SDI = 100 / T
Where T is the time (in minutes) from the start of the test until 100% plugging occurs.
Example: 100% plugging occurs at 4 minutes using a 0.45um membrane.
SDI = 100 / 4 = 25.0

‌If 100% plugging does NOT occur by 15 minutes:‌ Calculate using the following formula:
t = 0 min --> t₀ (s) = Time (seconds) to collect 500ml of filtrate at 30 psi pressure
t = a min --> tₐ (s) = Time (seconds) to collect 500ml of filtrate at 30 psi pressure after a minutes of testing
SDI=(100/(a-0))*((tₐ-t₀)/tₐ)

‌SDI 15 Value (Theoretical Maximum)‌  ‌Ranges:‌

Ultra-Filtered Water: SDI < 0.1

Filtered Water: 0.5 < SDI < 3

Waste Water: SDI > 5
At this point, calculating SDI over 10 or even 15 minutes becomes meaningful.