7777/7777D Immersion/In-Line Glass Mounting

Accurate pH and ORP monitoring and control in a range of industrial processes results in efficient product quality and reagent control. Honeywell’s 7777/7777D mountings provide cost effective and accurate pH measurements in easy in-line or immersion installations.

What Is It?
Honeywell’s 7777 series use either Durafet® II pH (7777D) or Meredian II pH/ORP electrodes that offer a reliable combination of pH measuring and reference electrodes together with an integral automatic temperature compensator in a 1-piece corrosion-resistant molded Ryton body.
The Durafet II non-glass sensor is durable and provides exceptionally fast response, making it ideal for a range of in-line applications. It produces low impedance pH signals even at low temperatures with no sodium error or ORP interference. The Durafet II mountings are available for only in-line installations.
The Meridian II pH/ORP electrodes use glass pH sensors and platinum or gold ORP sensors. These mountings are suitable for in-line and submersion applications. ​

How Does It Work?
​The Durafet II and Meredian II pH electrodes have a ¾-inch NPT thread at each end. This allows for direct screw-in insertion into process pipelines. The Meredian electrodes can also be screwed to the end of a pipe for immersion style applications. The electrodes’ compact size eliminates the need for O-rings or any special seals. Quick disconnect plugs enable easier installation and maintenance. 
While the combination Durafet II pH electrode includes a replaceable reference junction frit and gel for durability, the Meredian II includes a permanent but maintenance-free reference junction with gel fill. The junction’s large surface area resists fouling while its symmetrical annular shape minimizes the effects of electrical current passing through the process solution for improved pH measurement. ​

What Problems Does It Solve?
​Honeywell’s 7777/7777D assembly is easy to install, virtually maintenance-free and provides users with cost effective, yet accurate and dependable pH measurement. This leads to a smooth and hassle-free process, enhanced control and improved product quality.