HI-72911D pH Electrode for Cooling Towers and Boilers, DIN connector

The HI-72911D is a pH electrode with titanium body for cooling towers and boilers. This electrode is recommended for use with the HI-99141 pH meter. The HI-72911D uses general purpose (GP) glass, flat tip bulb, titanium body, and PTFE junction with polymer electrolyte.

General Purpose Glass Formulation

The measurement of pH at very high temperatures is detrimental to the sensitive glass bulb and will shorten the life of it. A pH electrode with general purpose (GP) glass will have a resistance of 100 megaohms at 25°C while the resistance of LT glass is around 50 megaohms at 25°C. As the temperature of the glass decreases in the sample, the resistance of the LT glass will approach that of GP glass. If using GP glass, the resistance would increase above the optimum range, resulting in increased impedance and ultimately affecting the measurement. The HI-72911D is suitable to use with samples that measure from 0 to 80°C.

Flat Tip Bulb

The recessed flat tip bulb of the HI-72911D is easy to clean and prevents solids in solutions from collecting on the sensor. Other tip shapes include conic for penetration and spheric for aqueous measurements.

Titanium Body

A titanium body increases immunity to electrostatic and magnetic fields. It also allows for strong corrosion resistance, even in seawater.

Matching Pin

A matching pin is a differential measurement technique used to eliminate ground loops and common mode perturbations for the measurement system. In a system without a matching pin, electrical currents in the sample can affect the reference half cell voltage that is connected via the liquid junction with the sample. In this case, the reference electrode picks up the electromagnetic fields and the measurement of the pH is altered. The matching pin isolates these current/magnetic fields from the reference electrode. The HI-72911D titanium body serves as a matching pin for safe precise pH measurements.

PTFE Junction

Porous polytetrafluoroethylene (PTFE) is a hydrophobic material that is available with different porosities. This type of junction is often used on electrodes with polymer electrolytes. Because of its chemical advantages, PTFE is widely used in industrial applications.

DIN Connector

The HI-72911D uses a DIN connector. This type of connector is generally proprietary to the meters they are supplied with and may not be interchangeable. The HI-72911D is designed for use with Hanna’s HI-99141 pH meter. Other types of connectors include BNC, screw type, T-type, and 3.5mm to name a few.