Technical blog
Problem solving
We offer a complete range of products and services for filtration, but above all the advice and technical assistance necessary to identify the most advantageous treatments for our customers, because they can improve the performance of the machines and, thanks to the programming of maintenance plans, hoc, help prevent breakdowns and arrests in production. La Ricambi Udinese offers hydraulic advice on filtration and similar, retrofitting sizing on filtration in pre-existing hydraulic systems.
PROBLEM SOLVING: DEFECT SEALING
The problem
Sometimes even the best filter cartridge can have unexpected defects. A customer called us because there were a number of malfunctions in oleodinamic plants, he complained starature of proportional valves and on-off valve stuck. From a first inspection, the facilities were properly designed and dimensioned on the side filtration, they were also all with the fluid in the off-line purification systems.
The cause
An analysis in the fluid line, however, has revealed a high degree of contamination of the system, especially of small particles. The first suspect went to the installed filters, where the filter cartridges had just been unified all with one brand and related correspondence.
The quality of the products installed was high and therefore the cartridges were not considered, so the focus was placed on any damages and / or on the block of the bypass valves, filters or other by-pass points. This point was immediately excluded, given that the problem was presented on all machines, making it very difficult that all the systems shown the same defects. After verifying the correct operation of the by-pass valves and the correct equivalence of cartridges, we decided to replace them on a machine, to verify that there had been no problems on the production lot. We removed the cartridge, but we found soon that it goes out very easily from the filter housing. So we checked the cartridge inner diameter, also considering the OR Ring thickness, that makes radial sealing for the intake side of the filter housing, finding an Increasing of 1mm in diameter, with respect to the inside diameter of the original cartridge.
A difference so high inevitably leads to create a by-pass on the seal: the fluid, once the cartridge is in work, if the differential pressure between the dirty and clean side increases, will tend to choose the path less tiring to cross the filtration media. The absence of filtration of the fluid, contributed to pollute the same fluid which created problems to the system.
The quality of the products installed was high and therefore the cartridges were not considered, so the focus was placed on any damages and / or on the block of the bypass valves, filters or other by-pass points. This point was immediately excluded, given that the problem was presented on all machines, making it very difficult that all the systems shown the same defects. After verifying the correct operation of the by-pass valves and the correct equivalence of cartridges, we decided to replace them on a machine, to verify that there had been no problems on the production lot. We removed the cartridge, but we found soon that it goes out very easily from the filter housing. So we checked the cartridge inner diameter, also considering the OR Ring thickness, that makes radial sealing for the intake side of the filter housing, finding an Increasing of 1mm in diameter, with respect to the inside diameter of the original cartridge.
A difference so high inevitably leads to create a by-pass on the seal: the fluid, once the cartridge is in work, if the differential pressure between the dirty and clean side increases, will tend to choose the path less tiring to cross the filtration media. The absence of filtration of the fluid, contributed to pollute the same fluid which created problems to the system.
The solution
We proceeded to install a particle counter in the filter exit manifold, measuring the contamination with the ink cartridge with the wrong OR and the correct one. We found that the solid particle contamination drop down with correct gaskets. After making sure of the cause of the problem, it was decided to install filter elements sealed correct and the problem was solved.
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