PH87/PH97 Retractable pH and ORP Assemblies and Electrodes

The PH87 retractable assembly is suitable for "Hot-Tap" service, allowing for removal from a pressurized process line or vessel without interrupting the flow or draining the tank.  The housing assemblies are constructed of chemically resistant titanium sheathes and are used with Model PH97 rugged sensors. The insertion assembly is suitable for service in a process line or tank where variable insertion lengths are required. Blowout protection is provided by the flared tip design of the titanium sheath that provides a metal-to-metal stop during retraction. Integral junction boxes are provided for simple installation and wiring.

The Model PH97 electrodes are designed to be durable and rugged for use with the PH87 assemblies. The PH97 is a combination all-in-one sensor for either pH or ORP in a rugged Ryton™ body. In many applications the large volume reference reservoir will provide an extended functional life.

Common Applications

  • Pulp and Paper Stock
  • Slurries
  • Process Tanks
  • Scrubbers



  • Suitable for Hot-Tap applications with ball valve
  • Integral Junction Box for simple installation
  • Titanium sheath for chemical protection
  • Adjustable insertion length
  • Integral anti-blowout guard
  • Built-in Solution Ground
  • Coaxial porous PTFE reference junction
Application Note

For control of batch neutralization, a pH measurement coupled with a timer-controlled chemical feed scheme provides very satisfactory results.

This system can be adapted for either acid waste or alkaline waste neutralization.


The treatment of wastewater from pulp and paper plants is a serious environmental concern. Yokogawa's submersion holder with an ultrasonic+air-jet cleaner (customized product) can reduce the manual cleaning frequency to just once every one or two months.

Industry:Pulp & Paper


Current trend for increasing mercury awareness throughout the public sector has caused the government to take action. Recently, the Environmental Protection Agency (EPA) has focused their efforts on controlling mercury levels produced in various coal fired power plants. Based on information from several case studies, the EPA developed the Mercury and Air Toxics Standards to cut back mercury emissions. The most popular technology utilized by coal plants to meet the new standards is a scrubber which cleans the off gas from the combustion process. ORP sensors can further monitor the effluent from these scrubbers to ensure optimal mercury emission levels are achieved. By closely monitoring the mercury concentrations in the effluent, plant managers will be able to easily confirm their plants are meeting the EPA's standards.




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