Transcript:
John Edwards here, talking about contamination control fundamentals, specifically hydraulic elements and element performance and what makes one manufacturer better than the other. In the industry, most of filter elements are rated using a multi-pass test. That's where in a lab type environment, the manufacturer can put an X number of particles into the system upstream of the filter and then measure the amount of particles downstream of the filter and from that, they can know exactly how many particles are caught by the filter element and from that, determine the efficiency of the filter and that's where beta ratios come from. Without getting into all of the calculations, a beta ratio actually lets you know what size particles a filter element may be catching and what efficiency rate it’s doing it at. If you got a filter element that’s catching 99.5% of all the particles that come in, that's pretty good, we call that high efficient, but at thousands of particles per milliliter, it’s still pretty important to get a high efficient high beta filter, also what's important is the beta stability, that actually lets one know how the element performs as it starts to fill it with particles during the life of the filter element. Most all manufacturers will have a good performance when that element is clean but as it starts to fill up in and has pressure pulses, how does it perform, that's beta stabilities, the way we measure that. Pressure rating is the amount of pressure drop that it takes for the fluid to get from one side of the filter to the other and the trick is to catch the particles with as low of a pressure drop as possible, that’s also important; and also the collapse rating, some of these filters are using high pressure applications where the differential pressure is pretty high and the core tubes have to be made out of more solid material as not to internally implode or crush inside the filter housing.