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WATER JET CONFERENCE - Waterjet Technology Association

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shaken just before use. SUPER<strong>WATER</strong> has been used successfully at temperatures from -15°F<br />

(Massachusetts) to 100°F (Utah).<br />

2. REDUCTION OF METAL EROSION<br />

A concern that polymerblasting might increase erosion of metal parts was allayed when it<br />

was determined experimentally that, in fact, erosion was reduced. In the summary to a Materials<br />

Laboratory Richmond report (26) the following points (quoted verbatim) were made. "The<br />

influence of SUPER<strong>WATER</strong> additions on metal erosion was studied in an experiment conducted<br />

on carbon steel heat exchanger tubes by the Richmond Refinery Chemical Cleaning Specialist.<br />

SUPER<strong>WATER</strong> additive was found to increase the incubation period for erosion by a factor of<br />

nine over plain waterblasting. This incubation period is the length of time that a metal surface<br />

can be directly exposed to the water jet without significant removal of metal. In addition, the<br />

initial surface metal erosion rate using a SUPER-<strong>WATER</strong> solution was found to be half of that<br />

for plain waterblasting." "We expect the addition of 3000 ppm SUPER-<strong>WATER</strong> polymer to<br />

hydroblast water will minimize erosive removal of metal surfaces and reduce the chance of<br />

damage to items being cleaned."<br />

3. INJECTION SYSTEMS<br />

The use of an appropriate system for injecting SUPER-<strong>WATER</strong> into the waterblast<br />

stream is critical to ensure optimum performance. Berkeley Chemical Research Inc. recommends<br />

injection systems specifically designed to proportionally meter SUPER-<strong>WATER</strong> at the optimum<br />

concentration of 0.3%. The polymer upon injection undergoes emulsion breaking and then<br />

hydration as discussed above. Because this hydration is not instantaneous and takes 2 to 3<br />

minutes to complete the polymer must always be injected ahead of the holding tank fitted to most<br />

high pressure waterblasting pumps.<br />

4. SAFETY CONSIDERATIONS<br />

The usual safety precautions employed during hydroblasting are appropriate for<br />

polymerblasting: see the OSHA Material Safety Data Sheet for SUPER-<strong>WATER</strong> . It should be<br />

noted the dilution of properties, apart from the flow characteristics, approach that of water.<br />

Neither polyacrylic acid nor polyacrylamide, or combinations, are listed in the so-called EPA<br />

Consent Decree (27) and neither are they included in the list of chemicals described as being<br />

carcinogenic in the December 1981 Second Annual Report on Carcinogens (28).<br />

At the Chevron U.S.A. Richmond Refinery it has been found that SUPER-<strong>WATER</strong> ,<br />

which is biodegradeable, does not foul the oxidation ponds (29).<br />

SUMMARY<br />

A description has been given of polymerblasting using SUPER-<strong>WATER</strong> concentrated<br />

industrial water blasting additive. The theory of enhanced efficiency and wide range of<br />

applications have been discussed. Also given were appropriate storage conditions, methods for<br />

mixing prior to use and the method of introducing the additive into high pressure waterblasting<br />

systems. ACKNOWLEDGEMENTS The author wishes to express sincere appreciation to Prof.<br />

Jack W. Hoyt (San Diego State University, California), Dr. Douglas A. McCombs (Western<br />

Industrial, Inter-mountain Division, Salt Lake City, Utah), Prof. David A Summers (University<br />

485

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