RPL - Model Arthur 026-301 -Simplified Respirometer Unit

The Simplified Respirometer is a low cost version of the fully automated model.  Although it is less automated, it has all of the important features of the Phase V, and it is just as capable of providing significant information.  The readout of volume of oxygen use is manual, not electronic, thus reducing the cost. A simple, sturdy instrument for many purposes.

On the following pages we invite you to explore the capabilities of the two models, the instrument specifications and some
of the test methods we have developed.

Respirometry Plus is currently searching for distributors in Asian and Latin American countries who are knowledgeable in activated sludge wastewater treatment.

• Aerobic or anaerobic test capability
• No contact between sensor and sample tested
• No limit on ambient air supplied to test chambers
• Vigorous airlift mixing of liquids prevents settling
• Fine bubble diffusion ensures excellent oxygen transfer
• Modular construction for easy cleaning, replacement of parts

Each measuring device utilizes a combination of sample chamber, carbon dioxide scrubber, volume manometer and air pump. The air pump provides continuous air circulation through the sample chamber and the scrubber. The entire air system is closed to the atmosphere. As the specimen in the chamber utilizes oxygen and generates carbon dioxide, the carbon dioxide is immediately removed by the caustic solution in the scrubber. The volume of carbon dioxide produced is, therefore, not present to balance the volume of oxygen utilized, and there is a net loss of gas volume equal to the volume of oxygen utilized. The change of gas volume is sensed by the gas volume manometer. It can also be used to measure the volume of gas produced, as in anaerobic processes.

Sample Chamber The instrument has a standard two-liter cylindrical chamber, but other sizes and shapes can also be provided. On the removable top of the sample chamber is a fill tube closed with a threaded plug. The plug is fitted with a syringe connector for calibration. Sample Chambers are disassembled to clean. With liquid samples the chamber utilizes an airlift pump to aerate and mix the sample. Air is distributed at the base of the airlift column through a fine bubble diffuser. Solid samples are usually placed on a set of porous, acrylic stages and air flows continuously through the solid samples on the stages.

CO2 Scrubber...The CO2 Scrubber is an acrylic tubular chamber containing 400 ml of potassium hydroxide solution. The purpose of the scrubber is to remove the volume of CO2 which is generated in metabolism so it will not interfere with the volume of oxygen used in respiration. A color indicator is added to the KOH solution that gradually fades when the CO2 absorption capacity is spent and must be replaced with new solution. The scrubber can be removed from the base to drain.

Air Pump...The Air Pump continuously forces air through the fine bubble diffuser in the sample chamber and CO2 scrubber at a rate of 3 liters per minute. The combination of fine bubble diffuser and airlift column creates a mixing reaction in the sample chamber to ensure good contact of organic matter, microorganisms and oxygen.

• Model No:.026-301 Single
• Sample Chamber (2-Liter): Inside, 4"D x 13"H Other sizes available:
• CO2 Scrubber - Inside 2 1/2"D x 13"H
• Net Weight: 25 pounds
• Shipping Weight: 30 pounds
• Air Pump:.Pumping rate: 3 L/min at 1 ft. Head
• Air Capacities: 1000 ml without venting
• Range of total oxygen demand: not limited
• Power Source.100-240V AC 50-60 Hz
• Output 12V DC 60 Watts
• Precision: + 2% as measured with sodium sulfite
• Warranty.Fully warranted against manufacturer’s defects for Eighteen months