Portable chillers made smaller.
What are possibly the smallest portable chillers on the market today have just been introduced by Advantage Engineering, Inc., Greenwood, Ind. The new Maximum series comes in both air- and water-cooled models and seven sizes from 5 to 30 tons. The unit features a new evaporator design, smaller "footprint," and improved electronic controls.
Replacing the tube-and-shell evaporators that have long been the standard with stainless-steel plate-type evaporators has reduced the chillers' size by 25-35% compared with tube-and-shell units of equal heat-transfer capacity, Advantage says.
In the plate-type evaporator, liquid refrigerant enters the heat exchanger and flows down one side of the corrugated steel plates. Water or water/glycol mixture flows down the other side and the plate design produces high turbulence and strong heat transfer between the two fluids, guaranteeing a steady flow of properly cooled water.
While the concept of plate-type heat exchangers is not new, it is only now becoming economically feasible to put them in chillers for plastics molding, according to Advantage spokesmen. The thin corrugated plates of stainless steel joined with copper brazing have rapidly become the standard in chillers for other markets, bringing down their manufacturing costs and making them a viable alternative for plastics chiller makers. Advantage believes in these heat exchangers so much that is has committed to use them in all of its units, discontinuing the tube-and-shell evaporators.
The plate-type exchangers' smaller size gives the chillers an added bonus of being more efficient as the same amount of refrigerant passes through a smaller area, resulting in flows of 20 ft/sec versus the 7 ft/sec of earlier chillers.
This increased velocity maintains a high rate of shear, keeping the surfaces inside the exchanger clear and reducing the possibility of fouling. The evaporators are also lighter than their predecessors and are not prone to rust, according to the company.
Other features include a plastic tank, condenser-water regulating valve, ball valves instead of gate valves, water manifold, and easy access to all internal parts.
Adding to the novelty of these chillers is Advantage's second generation of electronic controls. Based on six years of feedback from users of its first-generation controls, plus extensive research by in-house electronics engineers, Advantage designed a small yet highly functional controller. The unit features 22 dedicated "Go/No Go" diagnostic lights rather than error codes; an easy-to-set-up LED temperature setpoint and readout that can give temperatures in either Celsius or Fahrenheit; and a percent-of-capacity readout. SPI and Cincinnati Milacron CAMAC protocols are both standard.
Advantage says the units are slightly higher priced than many competing models, but offer more for the money because they include many standard features that are optional on other makes of chillers.
PHOTO : A small controller with dedicated diagnostic lights, an easy-to-set-up LED temperature setpoint, and a readout that can give temperatures in either Celsius or Fahrenheit run Advantage's new Maximum chillers.
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|Title Annotation:||Advantage Engineering Inc.'s Maximum series chillers|
|Date:||Apr 1, 1991|
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