Figure 1: Refrigerant Machine.

Table of Content

1. Measurements of glycol-based cooling systems
2. Glycol concentration monitoring with SRV
3. Detection of deposition and coolant degradation
4. Rheonics advantages over other systems
5. Outlook
6. Communication and Integration

1. Measurements of glycol-based cooling systems

The most widely used coolants are solutions of glycols and water, together with degradation and corrosion inhibitors to prevent coolant failures and corrosion of electronic and piping systems. Therefore, accurate and sensitive monitoring of glycol-based coolant condition is a crucial link to ensure the reliability and stability of equipment.
There are several methods currently used for monitoring of coolant condition. They measure two critical aspects of coolant properties:

• Glycol concentration can be measured by:
  • Viscosity, which varies strongly with concentration
  • Optical refractometry, which measures the index of refraction of the coolant, which is also dependent on glycol concentration
• Glycol degradation can be measured by:
  • Laboratory chemical analysis to detect expected degradation products
  • pH measurements to detect potentially corrosive acids in degradation products
  • Electrical conductivity measurements to detect ionic degradation products

Optimal monitoring of coolant condition should be a continuous online process whose reliability and stability should be maintained without calibration over the lifetime of the sensor.
Rheonics SRV is a compact, robust inline viscosity sensor that can reliably monitor viscosity and temperature of coolants directly in the coolant line. It can also detect and quantify material deposited by coolant, that give an early indication of corrosion products, biofilm formation, and other degradation processes.

Figure 2: Dimensions SRV Inline Viscometer G1/2″ Thread.

Figure 3: SRV mounted in HPT-12G for coolant line

SRV is exceptionally stable. Its factory calibration remains valid over its 25+ years of lifetime, therefore never requiring recalibration. Its resolution is better than 1% of viscosity reading. Reproducibility of readings is also better than 1%, making it perfect for tracking both short- and long term trends in coolant properties with a high degree of confidence. SRV incorporates a high accuracy temperature sensor immersed directly in the coolant that enables robust and accurate temperature compensation of viscosity readings. SRV further incorporates a self-checking function that indicates if the sensor has accumulated any deposits on its surface, from, for instance, corrosion products or adherent biofilms that can indicate chemical or biological degradation. Deposition checking functions independently of viscosity measurement, and can provide additional, crucial information about coolant condition.

2. Glycol concentration monitoring with SRV