Hach's pH sensors are available in a wide variety of body materials, mounting styles, pH electrode types, and cable connections. PEEK is suitable for most applications, and Ryton is preferred for use in clean water. Use the blue filter bar below to select the right inline process pH sensor for your application.
Hach Digital pHD sc sensors are available in convertible (PEEK® or Ryton®), insertion, and sanitary body styles. Three electrodes are used in these sensors to increase measurement accuracy and eliminate sensor ground loops.
Differential Electrode Measurement Technique
This ﬁeld-proven technique uses three electrodes instead of the two normally used in conventional pH sensors. Process and reference electrodes measure the pH differentially with respect to a third ground electrode. The end result is unsurpassed measurement accuracy, reduced reference junction potential, and elimination of sensor ground loops. These sensors provide greater reliability, resulting in less downtime and maintenance.
The former GLI, now a Hach Company brand, invented the Differential Electrode Technique for pH measurement in 1970. The pHD™ sensor series (U.S. Patent Number 6395158B1, May 28, 2002) takes this ﬁeld-proven technology to a new level.
Replaceable Salt Bridge/Protector
The unique, replaceable salt bridge holds an extraordinary volume of buffer to extend the working life of the sensor by protecting the reference electrode from harsh process conditions.
Built-in Encapsulated Preamp
Encapsulated construction protects the sensor’s built-in preamp from moisture and humidity, ensuring reliable sensor operation. The preamp in the pHD analog sensor produces a strong signal, enabling the sensor to be located up to 1000 m (3280 ft.) from the analyzer.
Durable Body Materials
Both the digital and analog pH and ORP differential sensors feature a durable PEEK® body for chemical compatibility with most process solutions. For less aggressive solutions, Hach offers a Ryton® sensor in a convertible style for pH and ORP measurement. A sensor with a stainless steel body is available for immersion applications.
Versatile Mounting Styles
Sensors are available in four mounting styles—convertible, insertion, immersion, and sanitary.