New chemical metering pump delivers major advance in long-life chemical metering

Watson-Marlow Fluid Technology Group (WMFTG) is unveiling the next performance level in its range of industry-leading Qdos chemical metering pumps. Qdos® Conveying Wave Technology (CWT™) extends the capabilities of peristaltic pump technology and offers longer service life than traditional tube-based designs. CWT™ also offers important advantages in water treatment applications; users will benefit from superior accuracy in chemical metering and dosing tasks, and the elimination of expensive ancillary equipment.

Qdos® CWT™ pumps achieve their peristaltic action by operating a unique fluid contact element that, in effect, offers the same basic function as the tube of a conventional peristaltic pump. As well as the elimination of vapour locking, the element delivers stable, reliable performance, even with fluctuations in ambient temperature and pressure. Furthermore, the robust mechanical design provides consistently high accuracy for the life of the pump.

To achieve the peristaltic pumping action, the CWT pump-head incorporates an EPDM element rather than a tube, which acts against a PEEK track. The resulting fluid contact element is subjected to very low stress levels, meaning the Qdos CWT pump will deliver significantly longer service life than a traditional pump.

Qdos CWT pumps offer outstanding chemical dosing accuracy in water treatment applications. The pumps introduce chemicals – including sodium hypochlorite for post-chlorination cycles – without the need to overdose, thus delivering consistently high accuracy for the life of the pump.

Among the pilot sites able to provide testimony is the San Luis Rey Water Reclamation Facility in Oceanside, California. The facility, which collects, treats and disposes of all of the city's sewage, favours the use of peristaltic pumps over diaphragm pumps for their ability to handle off gassing chemicals such as sodium hypochlorite. The installation of the Qdos CWT pump has enabled the site’s engineers to use peristaltic technology in an application where pressure spikes and off gassing affected more traditional pump types.  Since installation the San Luis Rey facility has experienced a significant increase in pump life.  

The sealed CWT pumphead – which delivers accurate, linear and repeatable flow – is also highly safe as it minimises operator exposure to chemicals, while changeover is possible in less than a minute without the need for tools. Qdos CWT users can gain from further operational and environmental safety through leak detection software, failure alarms and fluid recovery capabilities that avoid chemical waste.

From a usability perspective, the pump features a high-visibility keypad and TFT display, along with direct connectivity capability to a range of external monitoring systems.

“This is an exciting launch for us,” says Martin Johnston Strategic Business Development Director at WMFTG. “Qdos CWT is the next level in high performance for our industry leading Qdos® range of chemical metering pumps. Our objective was to design a technology that delivers all the benefits of a traditional pump but with significantly longer service life than traditional tube designs. It’s clear from early user feedback that CWT will help to deliver operational efficiencies to a wide range of users. We look forward to introducing more of our customers to its  benefits.”

Like all pumps in the range, the Qdos CWT is available in a number of variants that provide different levels of control, from Manual, Remote and PROFIBUS, through to Universal (automatic and manual control) and Universal+ (automatic and manual control with configurable 4-20mA input and output).

The new Qdos CWT range offers flow rates from 0.1 to 500 ml/min, and up to 7 bar RMS pressure. Flow control is up to 5000:1 with ±1% accuracy. To ensure suitability for industrial environments, the Qdos CWT features an IP66 NEMA 4X rated casing. A three year warranty is standard.