HACH GLI Differential ORP/pH sensor

Differential ORP/pH sensor

HACH GLI

The GLI differential ORP/pH sensor uses differential technology with three electrodes instead of the traditional two electrodes, and a built-in preamplifier, providing accurate and reliable performance. This ORP/pH sensor is available in corrosion-resistant Ryton or PEEK materials to handle strongly alkaline environments or reduce thermal creep, and the salt bridge can be replaced to extend the service life of the ORP/pH sensor.

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Operating Principle

The GLI differential ORP/pH sensor is based on differential electrode measurement technology, using three measuring electrodes instead of the two electrodes in traditional pH sensors. The pH values measured by the measuring electrode and the reference electrode are differential values relative to the third solution ground electrode. A preamplifier is used to amplify the output of each electrode, and the current signal is converted into the pH value of the water sample, which is the measurement result of the pH sensor.

Application Industries

The GLI differential ORP/pH sensor is suitable for industrial process monitoring in petroleum, pharmaceutical, papermaking and other industries; it measures, displays and transmits pH value and temperature in water treatment processes.

Features and Benefits

The GLI differential ORP/pH sensor adopts differential technology, with three electrodes replacing the two electrodes of traditional pH sensors, reducing drift and errors for accurate and reliable results.
The built-in preamplifier provides strong interference resistance, ensuring high-fidelity output signals from the pH sensor.
The GLI differential ORP/pH sensor offers a choice of Ryton or PEEK materials for measuring special water samples. The Ryton material pH sensor has good compatibility with strongly alkaline substances, reducing maintenance and downtime. The PEEK material pH sensor reduces thermal deformation.
The built-in field-replaceable salt bridge extends the service life of the GLI differential ORP/pH sensor.
The pH sensor is compatible with the HACH sc200 or sc1000 universal controller, featuring plug-and-play operation and multiple mounting options.
Optional self-cleaning assembly

Specifications

Measuring range: pH: 0 ～14 pH
ORP: -1500～+1500mV
Sensitivity: pH: ± 0.01pH
ORP: ± 0.5mV
Temp. range: -5～95℃
Maximum pressure: 6.9bar at 105℃
Probe material: PEEK, Ryton optional

Accessories Information

1000F3374-002 PEEK electrode protective sleeve
1000F3374-003 Ryton electrode protective sleeve
SB-P1SV Salt bridge for PEEK electrode
SB-R1SV Salt bridge for Ryton electrode
25M2A1001－ 115 200mV ORP standard solution, 500mL
25M2A1002－ 115 600mV ORP standard solution, 500mL
25M1A1025 －115 Electrolyte

Ordering Guide

Note:
A. When using a convertible sensor for immersion mounting, it is recommended to order the optional protective sleeve, whose material must match that of the sensor. This protective sleeve is connected to the sensor via threads.
B. The HF-resistant glass electrode pH sensor is implemented through an internal PFE (perfluoroelastomer) O-ring. C. To obtain the best ORP measurement results in solutions containing zinc, cyanide, cadmium or nickel, please specify the gold electrode.
Source: Public information from the HACH Water Quality website

Municipal Wastewater Treatment

Municipal Wastewater Treatment · Controllers and Sensors — Application Case

Site Conditions

This is a Municipal Wastewater Treatment customer whose plant is at the inlet, biological and outlet stages of a municipal plant. The main task was online water monitoring with a controller and sensor combination.

The Problem

The difficulty lies in high solids and corrosive fractions, with large diurnal flow swings; at the same time effluent parameters drift and probes foul with sludge and biofilm. Specification therefore means matching each controller channel to its sensor type.

What We Did

We took a Hach channel approach — supplying against the Hach original part numbers. Delivery was built around matching each controller channel to its sensor type, with point-by-point checks on: stable compliance with Grade 1A discharge limits and online data reporting.

Operating Outcome

In service the system performs as intended — factory-matched combinations that make faults easier to locate, with routine maintenance falling noticeably.

Food & Beverage

Food & Beverage · Controllers and Sensors — Application Case

Application Context

dosing, pasteurising, filling and CIP stages is a typical Food & Beverage duty. The project started from Controllers and Sensors, focusing on online water monitoring with a controller and sensor combination.

Process Constraints

frequent cleaning demands instruments that withstand hot CIP/SIP caustic cycles, and syrups, dairy and beverages that scale easily, under strict hygienic requirements only amplify it. The Controllers and Sensors specification must therefore cover matching each controller channel to its sensor type.

Delivery Approach

Delivery was handled as the Hach channel — supplying against the Hach original part numbers. Execution centred on matching each controller channel to its sensor type, together with food-safety and hygienic design per 3-A / EHEDG.

Field Results

Operation shows the benefit clearly — factory-matched combinations that make faults easier to locate, with confidence in this measuring point improving markedly.

Chemical & Pharmaceutical

Chemical & Pharmaceutical · Controllers and Sensors — Application Case

Customer Profile

The typical setting in Chemical & Pharmaceutical is reactors, metering vessels and finished-product tanks. The measuring point is Controllers and Sensors; the focus is online water monitoring with a controller and sensor combination.

Key Difficulties

Conditions are highly corrosive media with solvents and crystallisation, partly in explosive atmospheres and, on top of that, corrosion plus Ex protection shortens instrument life and makes downtime costly, which a standard configuration cannot handle for long. The design therefore starts with matching each controller channel to its sensor type.

Implementation

The scope ran through the Hach channel: supplying against the Hach original part numbers. Technically it hinges on matching each controller channel to its sensor type, and on these requirements: Ex certification and GMP traceability of records.

Customer Benefit

In practice this means factory-matched combinations that make faults easier to locate, which cut the workload on the site maintenance team.

Power & Energy

Power & Energy · Controllers and Sensors — Application Case

Project Background

The project covers boiler feedwater, turbine condensate and FGD/DeNOx systems. The work centres on Controllers and Sensors and the core task is online water monitoring with a controller and sensor combination.

Operating Challenges

The medium and duty are characterised by high temperature and pressure with both steam and saline water, and drift under high temperature and pressure, with very costly unplanned outages. So Controllers and Sensors cannot be specified generically — it calls for matching each controller channel to its sensor type.

Solution

The Ainstru engineering team worked through the Hach channel: supplying against the Hach original part numbers. The configuration involves matching each controller channel to its sensor type, with these requirements in view: compliance with power-industry codes and unit availability targets.

Results

Since start-up the system has run steadily; the practical result is factory-matched combinations that make faults easier to locate.

HACH

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GLI Differential ORP/pH sensor