This test method describes a procedure for the visual measurement of the color of light colored liquids. It can be referred to by several different names: APHA, Platinum-Cobalt, or Hazen. The measurement was originally developed to detect contamination of water supplies as detected by a slight yellow color. Today it finds use in many industries to measure slight yellowness to determine product quality (either degradation or impurities).
The APHA/Platinum-Cobalt color scale is described in ASTM D1209 “Standard TestMethod for Color of Clear Liquids (Platinum-Cobalt Scale)”. This ASTM method is an off-line manual laboratory method. The original test design required an observer to compare the color of a product to a known standard, and then judge the “color.” The APHA/Platinum-Cobalt color scale ranges from 0 to 500. The lowest value of 0 is referred to as water white. value of 500 is distinctly yellow.
Using a Guided Wave APHA/Platinum-Cobalt Color Analyzer system to automate this measurement within a process eliminates the visual judgment of a technician and delivers online real-time process control information to the process operators.
APHA Analyzer System Configuration
The Guided Wave Saybolt Color Analyzer system is a complete solution. The “ready-to-go” analytical system includes:
- Analyzer – ClearView® db filter photometer technology
- Fiber optic cables
- Sample interface – insertion probe or flow cell
- Control software and Saybolt application calibration
- Accurate, Real-time Reliable Results
The APHA/Platinum-Cobalt Color Analyzer system utilizes a Guided Wave multi-wavelength ClearView db filter photometer analyzer platform. It may be configured for either one (1) or two (2) independent sample monitoring points. The ClearView db analyzer is configured with application-appropriate wavelengths to measure the APHA/Platinum-Cobalt color of the sample. The analyzer employs a dual-beam design – meaning; the system has an continual internal optical reference check that allows it to self-compensate for signal variation due to non-sample conditions. This ultimately provides the system with long term stability. The final product is a total APHA/Platinum-Cobalt Color System that measures the color variation without interference from other factors.
The Smart Color Analyzer Choice
Complete APHA/Platinum-Cobalt (Hazen) Color Analyzer System:
- Unique dual beam optics – for long term, stable operation
- Up to two (2) independent measurement points – for added analytical flexibility at reduced cost per point
- High efficiency yet rugged fiber optics – analyzer electronics can be located away from a hazardous sample point
- In-door touch screen or Ethernet (Modbus TCP) – easy local or remote analyzer operation and control
- Analytical calculations are all encoded in the software – answers and alarms are clearly reported
Guided Wave’s APHA/Platinum-Cobalt Analyzer system delivers accurate, real-time process measurement results. Its linearity and repeatability, as well as its low maintenance requirements make it a cost effective, smart choice to help optimize production, improve yields, ensure consistent product quality and enhance profitability.
Options for a Custom Color Analyzer
Another advantage of the Saybolt Analyzer system is that is can be customized in many ways. For more information about specifications and analyzer operations contact us.
Specifications: APHA/Pt-Co (Hazen) Color Analyzer – Photometer
| Analyzer Technology | Fiber optic dual-beam ClearView db photometer (see also document #1033) |
|---|---|
| Fiber Connectors | SMA 905 |
| Light Source | Tungsten-Halogen, >4000 hours typical |
| Photometric Noise | <50 µAU 450-2100 nm 1 minute rms |
| Photometric Drift | <500 µAU rms/ °C |
| Response Time | 1 second, minimum. User settable |
| Measurement Range | 0-500 APHA/Platinum-Cobalt units (Pathlength can be optimized to increae sensitivity) |
| Measurement Accuracy | Complies with ASTM method D1209 |
| Power | 24 VDC, 3 A; 72 watts |
| Environmental | 0 – 45°C, 0 – 90%, sun and rain sheltered |
| Channels | Up to 2 (two) sample channels and optional turbidity monitoring |
| Outputs (analog) | Up to 6 for a one channel unit, Up to 4 per channel for a two channel unit, 4 – 20 mA, customer powered |
| Outputs (discreet) | Up to 6 for a 1 channel unit, Up to 4 per channel for a 2 channel unit, contact closures |
| Inputs (analog) | 4 (optional) 4 – 20 mA, isolated grounds |
| Local Display | LCD touch screen, color QVGA |
| Communications | Ethernet (TCP Modbus) standard |
| Enclosures | General Purpose NEMA 4 unclassified, Z-Purge, NEMA 4x, CI D2, X-Proof, ICEEx, ATEX, CI D1 |