Silton Online SDI Analyser

Product Overview

The Silton 4750 Online SDI Analyser is a fully automated, continuous-monitoring Silt Density Index (SDI) instrument engineered by Tech Inc. for reverse osmosis (RO) and membrane filtration facilities. Unlike manual SDI test kits that require an operator to collect samples and time each run, the Silton 4750 performs unattended SDI measurements around the clock, providing real-time data on feedwater fouling potential.

Designed in Vaughan, Ontario, Canada and manufactured at Tech Inc.’s advanced facility in Chennai, India, the Silton 4750 combines Canadian engineering precision with cost-effective Indian manufacturing. Tech Inc. is a Saudi Aramco approved vendor, and the Silton 4750 meets the requirements of ASTM D4189 — the international standard test method for Silt Density Index of water.

What Is SDI and Why Does It Matter?

The Silt Density Index (SDI) is a dimensionless number that quantifies the fouling potential of a water source by measuring how quickly a 0.45 µm membrane filter plugs under standardized conditions. It is the most widely used indicator for predicting whether feedwater will foul RO membranes, and is referenced in ASTM D4189.

SDI Acceptance Criteria for RO Systems:

• SDI < 1.0 — Excellent feedwater quality; minimal fouling risk
• SDI 1.0–3.0 — Acceptable for most RO membranes without additional pretreatment
• SDI 3.0–5.0 — Marginal; frequent membrane cleaning may be required
• SDI > 5.0 — Unacceptable; upstream filtration required to reduce submicron particulates

Continuous SDI monitoring with the Silton 4750 allows plant operators to detect pretreatment upsets immediately, optimize chemical dosing, and protect expensive RO membrane elements from irreversible fouling damage.

Principle of Operation

The Silton 4750 performs the ASTM D4189 SDI test automatically:

1. Feed water enters through the inlet and passes through a pre-screen filter.
2. The booster pump delivers water at 2.07 bar (30 psi) to the membrane filter holder.
3. Water flows through a 0.45 µm, 47 mm membrane filter. The system measures initial time (Ti) for 500 mL.
4. After 5/10/15 minutes, the system measures final time (Tf) for another 500 mL.
5. SDI is calculated: SDI = [(1 – Ti/Tf) / T] × 100.
6. Results display on screen, log to memory, and trigger alarms if thresholds are exceeded.

Technical Specifications

Measurement Parameters:

• Method: Automatic SDI per ASTM D4189
• Test Modes: SDI-5, SDI-10, SDI-15
• Sample Volume: 500 mL per cycle
• Membrane Filter: 0.45 µm pore, 47 mm diameter
• Operating Pressure: 2.07 bar (30 psi / 2 kg/cm²)
• SDI Range: 0.0–6.67 | Resolution: 0.01 | Repeatability: ±0.1

Components:

• Booster pump with pressure regulation
• Intelligent SDI sensing with precision flow measurement
• Microprocessor controller with LCD display
• SS membrane filter holder, temp/pressure sensors
• Wall-mounted IP-rated enclosure

Data & Communication:

• 1,000+ test result data logging
• 4–20 mA analog output for PLC/SCADA
• RS-485/Modbus for DCS integration
• Configurable alarm relay outputs

Operating Conditions:

• Feed Temp: 5–45°C | Ambient: 5–50°C | Humidity: 0–90% RH
• Power: 220V AC 50/60Hz (110V optional) | <150W
• Wetted Materials: 316 SS, PTFE, Viton®
• Enclosure: IP54 wall-mount | Connections: 1/4” or 1/2” NPT

Key Features and Benefits

• Fully Automated 24/7 Operation — No operator intervention needed
• Real-Time SDI Monitoring with instant digital readout
• ASTM D4189 Compliant with regulated pressure and calibrated flow
• Intelligent Alarm System with configurable relay outputs
• Plant Integration via 4–20 mA and RS-485/Modbus
• 1,000+ Result Data Logging for trend analysis
• SDI-5, SDI-10, SDI-15 test modes with 100/500 mL volumes
• Low Maintenance — only filter disc replacement required
• 316 SS/PTFE/Viton® corrosion-resistant construction
• Side-stream sampling prevents stagnation

Applications and Industries

• Seawater Desalination — SWRO pretreatment monitoring
• Brackish Water RO — Well/surface water quality assurance
• Industrial Process Water — Power, semiconductors, pharma, food/beverage
• Municipal Water Treatment — Pre-RO monitoring in drinking water and reclamation
• Oil & Gas — Produced water and injection well membrane protection
• R&D / Academia — Automated fouling research data collection
• Pretreatment Optimization — Evaluate filters, UF, and chemical programs

Standard Package Includes

• Silton 4750 SDI Analyser (wall-mount enclosure)
• Booster pump and pressure regulation assembly
• SS 47 mm membrane filter holder
• 100x 0.45 µm membrane filter discs
• Fittings, tubing, power cable, and hardware
• Operation manual and factory calibration certificate
• 12-month manufacturer warranty

Why Choose Tech Inc.?

• Canadian Engineering + Indian Manufacturing = world-class at competitive prices
• Saudi Aramco Approved Vendor
• Complete water treatment equipment ecosystem
• Worldwide shipping (50+ countries) with remote support
• Customization available for connections, voltage, protocols, materials

Standards: ASTM D4189 | ISO 9001/14001/GMP compatible

Frequently Asked Questions

Q: What is the Silton 4750?

A: A fully automated online SDI analyzer per ASTM D4189 with booster pump, pressure regulation, sensing system, controller, and display.

Q: How does it differ from manual SDI kits?

A: It automates everything — pressure, timing, calculation, logging, alarms — 24/7 without operator presence.

Q: Can it connect to SCADA?

A: Yes, via 4–20 mA analog and RS-485/Modbus RTU for PLC/SCADA/DCS integration.

Q: What filter does it use?

A: Standard 47 mm, 0.45 µm discs (Millipore, Pall, Whatman, Sartorius). 100 included.

Q: Suitable for seawater?

A: Yes — 316 SS, PTFE, Viton® wetted parts. Widely used in SWRO plants.

Q: How to get a quote?

A: Visit techincresearch.com or email mail@techincresearch.com for quotations with specs, delivery, and installation support.

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