Bespoke dosing equipment for plastics processor

Watson-Marlow Bredel is renowned for high-quality off-the-shelf pumps, but company also undertakes the design and manufacture of bespoke OEM pump systems, recently supplying ColorMatrix with a design

ColorMatrix Europe is part of the ColorMatrix Group of Companies, a global leader in liquid colorant and additive technologies for the plastics industry, serving both the injection moulding and extruding sectors.

One of the latest products to be added to the ColorMatrix range is the CM500 dosing unit that can dispense up to 1.66 ml/s into injection moulding or extrusion processes.

Commonly handling colorants, the unit can also handle a variety of additives such as scavengers which prevent packaging tainting the taste of foods and beverages, as well as enhancers to improve material processing properties, UV absorbers and slip additives.

Many of the colorants are based on organic surfactants and oils and are generally free flowing, but viscosities can be as high as 12000 centipoise (similar to corn syrup).

The most economical pumping, metering and dispensing method for such fluids is by peristaltic pump.

So, rather than develop a pump from scratch, ColorMatrix decided to prepare a detailed specification and use a know manufacturer to design, develop and produce the unit.

Watson-Marlow Bredel was awarded this contract, being the world's leading manufacturer of peristaltic pumps.

When working on the ColorMatrix project, Watson-Marlow Bredel based the pump design around a new 300 series pump that was not yet launched on the market as a standard product.

Added to this pump was a specially designed controller and signal interface which allows the operator to view information such as pump speed, and guides the user through programming and calibration functions.

The whole unit is housed in a casing similar to that used for Watson-Marlow Bredel range of scientific pumps.

In a typical application, the unit may dispense several different colours in a day, so it is important to have quick changeovers with no need for cleaning.

Watson-Marlow Bredel was able to offer a pump-head that allows the tubing to be changed without tools and with automatic tube tensioning.

While most customers use 4.8mm bore silicone tubing, low-dose applications can utilise a smaller tube within the same pump-head.

For handling aggressive fluids, Watson-Marlow Bredel Marprene tubing can be specified instead.

Although Watson-Marlow Bredel is renowned for producing high-quality off-the-shelf pumps, the company also undertakes the design and manufacture of bespoke OEM pump systems.

Where appropriate, specialists are sub-contracted to undertake tasks such as programming to enable the pump, controller, display and any auxiliary inputs or outputs to be integrated so as to perform particular functions.

With the ColorMatrix project, the programming included a facility to allow the operating language to be selected from English, French, German, Dutch, Spanish and Italian.

Pump speed range 0.1 to 50rpm and extrusion-tracking can be input as a 4-20mA or 0-10V DC signal.

All units allow the user to choose between a potential-free or 24V DC run signal, and there is a multi-regional mains input of 115-230V AC at 50/60Hz.

An agreement was signed whereby Watson-Marlow Bredel took responsibility for the design and development of the dosing unit to meet the specification and ColorMatrix is contracted to accept 235 units over a two-year period.

Brian Jones, Equipment Development Engineer for ColorMatrix Europe, comments: " Watson-Marlow Bredel has proved to be an excellent business partner, rigidly adhering to the specification, although flexible when late changes were requested.

The CM500 peristaltic dosing units have been popular with our customers, being easy to set-up and use, as well as thoroughly reliable.

We would certainly be prepared to work with Watson-Marlow Bredel on future projects".

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