HI72911D Titanium Body pH Electrode for Boilers and Cooling Towers with DIN Connector
HI72911D Titanium Body pH Electrode for Boilers and Cooling Towers with DIN Connector Ph Electrodes & Probes Selangor, Malaysia, Penang, Sabah, Kuala Lumpur (KL), Petaling Jaya (PJ), Sungai Nibong, Kota Kinabalu Supplier, Suppliers, Supply, Supplies | Hanna Instruments (M) Sdn Bhd HI70671L Cleaning & Disinfection Solution for Algae, Fungi and Bacteria (500 mL) HI70670L Cleaning Solution for Salt Deposits (500 mL) HI70663L Cleaning Solution for Soil Deposits (500 mL) HI70300L Electrode Storage Solution (500 mL) HI7061L General Purpose Cleaning Solution (500 mL) HI7010L pH 10.01 Calibration Solution (500 mL) HI7007L pH 7.01 Calibration Solution (500 mL) HI7004L pH 4.01 Calibration Solution (500 mL)
RM 1,060.00
500 g
1 in stock
The HI72911D is a titanium body, polymer filled, double reference junction pH electrode with a DIN connector. This flat tip sensing portion of this electrode is made with general purpose glass.


The HI72911D also has a PTFE type junction along with a built-in temperature sensor and amplifier within a single probe design. This design consideration is ideal for measuring the pH in boilers and cooling towers. The HI72911D is designed for use with Hanna’s HI99141 pH meter.

  • Titanium Body
  • Built-In Temperature Sensor
  • Recessed, Flat Tip


Hanna Instruments offers a wide variety of pH electrodes that are designed for many different applications. The type of glass used for sensing pH, bulb shape, body material, type of junction, type of reference and electrolyte used are just some of the design considerations.

The HI72911D uses general purpose (GP) glass, flat tip bulb, titanium body, and PTFE junction with polymer electrolyte.

gp glass

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 HI72911D is suitable to use with samples that measure from 0 to 80°C.

flat tip bulb

Flat Tip Bulb

The recessed flat tip bulb of the HI72911D 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

Titanium Body

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


titanium body

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 fields and the measurement of the pH is altered. The matching pin isolates these current/magnetic fields from the reference electrode. The HI72911D titanium body serves as a matching pin for safe precise pH measurements.

flat tip bulb

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

DIN Connector

The HI72911D uses a DIN connector. This type of connector is generally proprietary to the meters they are supplied with and may not be interchangeable. The HI72911D is designed for use with Hanna’s HI99141 pH meter. Other type of connectors include BNC, screw type, T-type, and 3.5mm to name a few.



Single Junction Versus Double Junction pH Electrodes

single double junction electrode


Conventional electrodes are normally single junction. As depicted by the figure above, these electrodes have only a single junction between the internal reference wire and the external solution. Under adverse conditions, such as high pressure, high temperature, highly acidic or alkaline solutions, the positive flow of the electrolyte through the junction is often reversed resulting in the ingress of sample solution into the reference compartment. If this is left unchecked, the reference electrode can become contaminated, leading to complete electrode failure. Another potential problem with single junction electrodes is the clogging of the junction due to silver chloride (AgCl) precipitation. Silver can be easily precipitate in samples that contain Tris buffer or heavy metals. When the electrolyte solution makes contact with the sample, some AgCl will precipitate on the external face of the junction. The result is drifty readings obtained from the sensor.

Hanna’s double junction system, as the name implies, has two junctions, only one of which is in contact with the sample as shown in the figure. Under adverse conditions, the same tendency of sample ingress is evident. However, as the reference electrode system is separated physically from the intermediate electrolyte area, the contamination of the electrode is minimized. The likelihood of clogging of the junction is also reduced with a double junction electrode since the outer reference cell uses a fill solution that is “silver-free”. Since there is no silver present, there is no precipitate that can form to clog the junction.



Body Material titanium body working as matching pin
Reference double, Ag/AgCl
Junction / Flow Rate PTFE
Electrolyte polymer
Range pH: 0 to 13
Max Pressure 3.0 bar
Tip Shape flat
Diameter 14 mm
Body Length / Overall Length 110 mm / 150.5 mm
Recommended Operating Temperature 0 to 80°C (32 to 176°F) - GP
Temperature Sensor yes
Matching Pin yes
Amplifier yes
Digital no
Cable 7-pole; 1 m (3.3')
Connection DIN
Applications boilers, cooling towers

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