Norgren Collateral

08 Solutions Q&A 2.5 Performance 2.5.1 Performance of general purpose filters Filters have their flow measured in terms of the pressure drop across them. As the flow increases then the pressure drop also increases. These pressure drops are energy losses in the system. A well designed filter not only removes water and particles efficiently, but also has a low pressure drop at a given flow. The flow figures quoted in IMI Norgren catalogs for general purpose filters are at a pressure drop of 5 psig (0.3 bar), from a 100 psig (7 bar) inlet pressure. Beware! not all competitors quote their flows under the same conditions. If a higher inlet pressure is used or a higher pressure drop is quoted then the apparent flow will be higher. This does not mean it is a better unit , simply that a different point on the curve has been selected. Often the only way to compare units is to test them under the same laboratory conditions. 2.5.2 Performance of coalescing filters: The maximum flow of an oil removal filter is usually determined by the oil removal efficiency under saturated conditions. In the catalog there are maximum flows quoted 'to maintain stated oil removal characteristics.' These are the steady state flows which should not be exceeded to guarantee that the oil in the outlet air remains below the 0.01ppm (parts per million) quoted. Cyclic or pulsating flows will result in oil carry over, as will elevated temperatures. If a higher oil carry over is acceptable (or there is no oil in the air-line) then higher flows are achievable, and will be determined by the 'acceptable' pressure drop. For a new (dry) element a flow which gives a pressure drop of less than 5 psid (0.3 bar) is recommended. 2.6 Simple filter troubleshooting Malfunction Possible cause Remedy Excessive pressure drop Micron rating of element to small for application Use larger micron size element Filter element blocked 1. Clean element (not coalescing element) 2. Replace with new element Flow requirement greater than filter capacity Use larger filter Dirt passing through filter Element seals missing or defective. (N.B. seals not required on some units). 1. Replace seal 2. Tighten element Damaged element Replace element Water passing through filter Water level in bowl above baffle Drain water Flow capacity of filter exceeded Maintain flow within capacity of filter or change to filter capable of handling desired flows Crazing of Polycarbonate bowl or milky appearance Bowl has been cleaned with imcompatible fluid Replace bowl. Clean only with warm water and soap. Bowl is being used in an area containing fumes or vapors incompatible with polycarbonate. Replace bowl. Eliminate source of problem of convert from plastic to metal bowls Compressor oil vapor may be causing problem Replace bowl. Eliminate source of problem of convert from plastic to metal bowls Air intake to compressor may contain fumes or vapor incompatible with polycarbonate. Replace bowl. Eliminate source of problem of convert from plastic to metal bowls Water beyond the filter Inlet air has a high temperature and as it cools downstream, moisture condenses to water Fit dryer, pre-cool air or fit filter immediately prior to application. Filters (cont.)

• Cover