Petroleum compounds, such as refined hydrocarbon distillates, are generally a difficult-to-clean, oily, molasses-like substance. Traditionally, these compounds are cleaned using hydrocarbon solvents such as diesel fuel; however, this process can be hazardous to personnel and can create environmental disposal problems. In addition, some solvents are illegal due to ozone depleting effects – and flammable solvents can only be used in a Class I, Division II explosion-proof area. Converting to an aqueous-based method can eliminate all of these concerns and will be less costly. The question is: Will an aqueous system clean as effectively as a solventbased system? The answer is yes. Miele’s PG 8536 is the perfect solution.
Effective aqueous cleaning is based on a balanced interaction of four important Factors:
In general, hotter water provides better cleaning and rinsing. Miele washers can heat wash and Dl water up to 95°C. Additionally, wash and Dl water temperatures are independently adjustable on Miele systems for maximum flexibility. For cleaning of petroleum based compounds a wash temperature of 95°C is recommended, followed by a Dl rinse with acid neutralizer, then one or two Dl Rinses heated to 95°C.
It is often assumed that high pressure must be used to provide good cleaning results, but higher pressure also means a greater chance of glassware breakage. Miele’s high turnover rate (circulation) of water at a low discharge pressure provides superior results without risk of glassware breakage. Using only 2.5 gallons of water per cycle, the Miele PG 8536 glassware washer circulates at a rate of 156 gallons per minute. This compares with 25 gpm for typical household dishwashers and 60 gpm for typical lab washers. Miele’s high circulation rate ensures analytically clean results; reduces wash time required, aids in energy efficiency and allows for lower detergent usage. The Miele lower spray arm also features special spray nozzles which angle and feather the jet spray for maximum coverage and impingement.
Most labs cannot spend the time waiting for a washer to complete long cycles. In addition to high circulation rates providing faster cleaning, The PG 8536 utilizes only 2.5 gallons of water per cycle, which is heated by 6000 watts of power at 220 V. This means less time is wasted waiting for water to be heated to temperature. For cleaning of petroleum compounds, a longer wash cycle may be necessary. The wash time on the Miele PG 8536 is programmable, making it flexible for customized washing protocols.
Selecting proper detergents is an important step in achieving critically clean glassware. Miele offers an extensive line of powder and liquid detergents, and acid neutralizers. For petroleum compound applications, liquid detergent, neodisher® FLA has proven effective in combination with an acid neutralizer, and neodisher EM emulsifier- to aid in suspending hydrophobic hydrocarbons in solution.
Because of the nature of petroleum compounds, the door and sump pump seal are likely to deteriorate quickly, causing leaking. Miele utilizes grease resistant NBR polymer gaskets which are chemically resistant to petroleum compounds. The thick nature of these compounds can also cause sump filters to become clogged – but Miele’s triple filter system is easily removed for cleaning. In some instances, Miele’s wash protocol includes an extra wash cycle simply to “de-gunk” the washer.