| Build a better ProWeigh Filter |
| Monday, 30 November 2009 13:47 |
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Building a Better ProWeigh® Paul Strickler, Environmental Express Vice President Product Development Environmental Express has long been the industry leader in providing preweighed filters for solids testing. In fact, our ProWeigh filters have been specifically approved for over ten years by Standard Methods for total dissolved solids (Method 2540C, total suspended solids (Method 2540D) and total volatile solids (Method 2540E).
Previously, each of the half-dozen or so manufacturers of glass fiber filters in the world have offered a product that is suitable for TSS & VSS, but none have offered a filter that was specifically designed for TSS – until now. Our new ProTemp binderless borosilicate glass fiber filter material is a significant improvement to existing filters in three ways. First, the material is more weight stable at volatile temperature of 550°C. Previously, many lots of filter material were rejected for use as VSS product due to their inability to meet our quality control criteria for weight stabilization after high temperature heating. Now, every lot of our ProTemp filter material is more stable than even the best lots of other manufacturer’s material.
Second, our ProTemp filter material gives more consistent blanks because it is more resistant to fiber loss from moving water. No more negative blanks due to loss of fibers. Finally, the surface finish and fiber size is more uniform. There are virtually none of the larger glass particles (called shot in the industry) that can wash out during analysis, diminishing results. We have also upgraded our filter cutting process. We now use a 75 watt CO2 laser that cuts perfect filters of any size with a focused laser beam instead of traditional cutting dies and presses. Take a look at our filters and note how uniform the outer edge is. This melt-cut edge maintains its integrity and resistance to fiber loss as each individual filter is washed repeatedly with DI water as the method requires. Functionally, this means that there is less damage to the filter surface and less loose fiber that can be lost in the process and affect the final weight. Finally we have upgraded our robotic system and are now using dedicated weigh cells instead of standard analytical balances for all 42mm, 47mm and 55mm ProWeigh filters. These certified weigh cells are much faster, and stabilize much more quickly than the analytical balances. They are so incredibly fast that we configure them for maximum stability possible before a weight is registered. Also, there is virtually no drift. ProWeighs have always easily met the requirement of being weight reproducible to 0.5mg. Now, the weights are even tighter and closer to the mean. Improved filter material, improved preparation and more accurate weighing result in a better product that always meets the needs of your laboratory. Environmental Express is committed to constant improvement of our processes and products to improve your results and save you time. |
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