Residual Analyzers

Residual Analyzers, Including Reagentless Chlorine Analyzers, Fruit Washing Chlorine Analyzers, and High Range Chlorine Analyzers

For maximum safety in the production of clean water, it is essential to chlorinate to the point of establishing a level of residual chlorine. Assurance that the treatment has been properly carried out must be confirmed through the usage of testing equipment capable of measuring residual chlorine levels.

Hydro Instruments offers a collection of advanced residual analyzers that can be relied on for years of accurate measurements. Made with the finest corrosion-resistant materials available and thoroughly tested during assembly, our residual chlorine analyzers are capable of providing precise readings in applications where accuracy is a necessity.

To achieve and maintain the desired flow rate for water samples, the usage of a flow meter and rate control valve in conjunction with a residual analyzer may be necessary. Call Hydro Instruments for further information and to find a chlorine analyzer that matches your industry’s particular specifications.

Definition of Terms & Types of Chlorine Commonly Measured

Residual Chlorine – The available chlorine remaining after the reaction interval and still available to combat the more resistant organisms and to safeguard against any later contamination.

Free Chlorine – The portion of the total residual chlorine remaining in the chlorinated water or waste at the end of a specified contact period, which will react chemically and biologically as hypochlorous or hypochlorite ions.

Applications typically measuring free chlorine residual include:

  • Municipal Drinking Water Treatment
  • Cooling Tower
  • Fruit & Vegetable Wash-down

Combined Chlorine – The portion of the total residual chlorine remaining in the chlorinated water or waste at the end of a specified contact period, which will react chemically and biologically as chloramines or organic chlorine.

Total Chlorine – The sum of both the free chlorine residual and combined chlorine residual.

Applications typically measuring total chlorine residual include:

  • Municipal Waste Water Effluent
  • Pool & Spa

Measurement Methods

Peracetic Acid: Disinfection – During the measurement process, peracetic acid is often utilized as a disinfectant. It’s capable of eliminating large quantities of microorganisms in a short period of time.

Colorimetric – Uses DPD reagents that cause a chemical reaction to change the color of the water. A photocell is used to determine the residual concentration of the sample based on the color change.

Amperometric: Open Cell – Uses two electrodes in direct contact with the sample water, with the sample water acting as an electrolyte. An electrical signal is produced proportional to the residual concentration. The monitor is able to determine the residual level of the sample water based on the strength of this electrical signal.

Amperometric: Probe – Uses two electrodes submerged in an electrolyte behind a permeable membrane. The target disinfectant species is able to permeate through the membrane where it can read. An electrical signal is produced proportional to its concentration. The monitor is able to determine the residual level of the sample water based on the strength of this electrical signal.

Potentiostatic: Probe – Uses three electrodes that operate in the same fashion as the Amperometric: Probe style.

Hydro Instruments’ Residual Analyzers

Model No. RAH-210

Applications

Municipal drinking water, Municipal wastewater effluent, Cooling tower, Fruit & Vegetable wash-down, Pool & Spa

Disinfectant

Free Cl2 or Total Cl2

Measurement Method

Amperometric: Open Cell

Key Benefits

  • Versatile and field-adjustable measurement range
  • Tolerant to less than optimal water quality

Advantages

  • Readings are not affected by air bubbles
  • Inexpensive maintenance
  • Self-cleaning measurement electrodes

Disadvantages

  • Sample water pH must be compensated for
  • Total Cl2 measurement requires KI reagent
  • Moving parts
  • Water cannot contain corrosion inhibitors

Learn more about the RAH-210

Model No. RAH-280

Applications

Municipal drinking water, Municipal wastewater effluent, Cooling tower, Fruit & Vegetable wash-down, Pool & Spa

Disinfectant

Free Cl2 or Total Cl2

Measurement Method

Amperometric: Open Cell

Key Benefits

  • Versatile and field-adjustable measurement range
  • Tolerant to less than optimal water quality
  • Large 320×240 pixel, color graphical display
  • Live graph charting

Advantages

  • Readings are not affected by air bubbles
  • Inexpensive maintenance
  • Self-cleaning measurement electrodes

Disadvantages

  • Sample water pH must be compensated for
  • Total Cl2 measurement requires KI reagent
  • Moving parts
  • Water cannot contain corrosion inhibitors

Learn more about the RAH-280

Model No. RPH-250 (Reagentless Analyzer)

Applications

Municipal drinking water, Cooling tower, Fruit & Vegetable wash-down, Rubber processing, Pool & Spa

Disinfectant

Free Cl2, Total Cl2, Chlorine Dioxide… (Others available, see RPH-250 product literature)

Measurement Method

Amperometric: Probe or Potentiostatic: Probe

Key Benefits

  • A wide range of disinfectant sensors are available to meet application needs.
  • We also have high-range chlorine analyzers. They can be used for applications requiring a very high range of residual measurement
  • Reagentless chlorine analyzer

Advantages

  • Inexpensive maintenance
  • Very easy and simple maintenance
  • Self-cleaning measurement electrodes* (Air bubbles in the sample do not affect reading.)

Disadvantages

  • Free Cl2 measurement requires sample water pH compensation
  • Air bubbles in the sample can affect readings
  • Changes in sample water pressure and flow can affect readings
  • Requires periodic control of sensor signal

(*) Only for F3 and D3 disinfectant sensors

Learn more about the RPH-250

Model No. RPH-260 (Reagentless Analyzer)

Applications

Municipal drinking water, Cooling tower, Fruit & Vegetable wash-down, Rubber processing, Pool & Spa

Disinfectant

Free Cl2, Total Cl2, Chlorine Dioxide… (Others available, see RPH-260 product literature)

Measurement Method

Amperometric: Probe or Potentiostatic: Probe

Key Benefits

  • There are a wide range of disinfectant sensors available to meet application needs
  • High range chlorine analyzer can be used for applications requiring a very high range of residual measurement
  • Reagentless chlorine analyzer
  • Up to two (2) different disinfectant sensors can be used simultaneously
  • Large 320×240 pixel, color graphical display
  • Live graph charting

Advantages

  • Inexpensive maintenance
  • Very easy maintenance
  • Self-cleaning measurement electrodes* (Air bubbles in the sample do not affect reading.)

Disadvantages

  • Free Cl2 measurement requires sample water pH compensation
  • Air bubbles in the sample can affect readings
  • Changes in sample water pressure and flow can affect readings
  • Requires periodic control of sensor signal

(*) Only for F3 and D3 disinfectant sensors

Learn more about the RPH-260

For Advanced Chlorine Analyzer Technologies, Call Hydro Instruments

Since 1978, Hydro Instruments has developed innovative and effective flow measurement monitoring equipment for clients worldwide. With our line of residual gas analyzers and chlorine measuring systems, water supply centers, food processing plants, and other industries can have confidence they’re receiving accurate readings. 

Contact us today to learn more about our residual analyzers and to place an order.