Filtration HandbookIn the following pages you will find the     Awareness of fluidsbasic principles of filtration illustra...
Once the direct connection between                  fluid condition and the profitability and                  efficiency ...
Why is filtration so important?The selection of the perfect filtration                                                    ...
Causes of contamination                  What are the causes of contamination and which mechanisms can lead to a          ...
Particularly critical are particles whichare the same size as the clearance                                               ...
What types of wear are there?                  1. Abrasion                             1. Abrasion                  by par...
Effect of erosion:                        2. ErosionThe high velocity of the fluid forcesexisting particles against the co...
The smallest cracks in the surface are   4. Surface fatigue                  hollowed out causing material to break       ...
How clean should the fluid be?Classification of the solid particle         Particle counting method                       ...
Cleanliness requirements                    Type of system/Area of application/             Recommended cleanliness       ...
What kind of filters are there and when are they used?Installation location of filters                                    ...
Pressure filters                  Pressure filters are fitted after the                                               CONT...
Return line filtersReturn line filters are located in the                                              CONTROLreturn line ...
Return line & suction boost filters                  The return line & suction boost filter                  RKM was desig...
Offline filterIn hydraulic systems with heavy loads,                                                CONTROLadditional offl...
Tank breather filters                  Tank breather filters are one of the most                                       CON...
Summary                                                                                                                   ...
Filter selection                  Filter efficiency is the most important                Protective filter                ...
Selection of the appropriate filter materialThe variety of applications of HYDAC filters has given rise to different eleme...
Filter sizing                  Once the element material, the                  Use as              Filter construction    ...
How to proceed in practice?If you calculate on the generous side,       The size of the filter can be determined with the ...
Filter calculation according to              Example of concept optimization using the electronic tool "Optimize-IT":     ...
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E7011 0-02-08 filterfibel-katalogversion

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E7011 0-02-08 filterfibel-katalogversion

  1. 1. Filtration HandbookIn the following pages you will find the Awareness of fluidsbasic principles of filtration illustrated As a manufacturer or operator of machines or systems in todays fast movingand explained using simple examples. and globalized market in Central Europe, every possible means must be taken to continually improve competitiveness.For filtration and hydraulicsspecialists requiring more detailed In the first instance, this implies reduction in costs, not only of the purchase costinformation, we recommend but of all costs generated during the whole lifetime of the system (life cycle costdownloading our complete filtration reduction).handbook (www.hydac.com).If you have any questions about the Objective: Life Cycle Cost Optimizationcontents of this brochure or if youhave a specific problem to solve,we will be happy to help you inperson. Please contact your nearestHYDAC representative or contact ourheadquarters. Costs purchase cost one-off installation phase operating phase disposal phase Time The condition of the operating fluid plays a key role in this objective since approximately 70 % of all breakdowns of hydraulic and lubrication systems can be attributed to the condition of the oil - with proven detrimental effects on the efficiency and profitability of systems and equipment. Others: 30 % Related to fluid condition: 70 % Causes of breakdowns in hydraulic and lubrication systems E 7.011.0/02.08 7
  2. 2. Once the direct connection between fluid condition and the profitability and efficiency of hydraulic and lubrication systems is recognized, the action required becomes obvious: cooling, continuous online conditioning and a well-engineered filtration concept guarantee the efficiency and operating reliability of the whole system. Although this filtration handbook - as the name suggests - deals primarily with the "filter" component, HYDAC experts will also provide you with modern solutions which are specific to your system in the areas of cooling and condition monitoring. Only by taking a holistic approach is it possible to improve the condition of fluid the fluid used and to reduce the Life awareness Cycle Costs. As HYDACs hydraulic experts, we want to focus attention on fluid awareness and we would like to share our experience with you. The following pages relate to filtration, but we can also help you in relation to cooling and condition monitioring if required.E 7.011.0/02.08 8
  3. 3. Why is filtration so important?The selection of the perfect filtration What kinds of damage doessolution contributes significantly contamination cause?to preventing damage caused bycontamination, to increasing the Contamination has a detrimental effectavailability of the system and therefore on the functions of hydraulic andto increasing productivity considerably. lubricating fluids, e. g. transfer of heat and energy, right up to system failure.The new filter element technologyBetamicron®4 has been specially From subsequent damage analysesdeveloped for the reduction of approx. 75 % of system failuresthe Life Cycle Cost. The previous can be attributed to damage toglass fibre elements from HYDAC the components used, caused by(Betamicron®3 generation) provided contamination of the operating fluid.complete security: a high level of fluidcleanliness and long-term stability foryour hydraulic or lubrication system.The new generation goes one better:with further improvements to theperformance data the elements withBetamicron®4 technology ensurethe highest fluid cleanliness. Byoptimizing the filter media structureboth the separation performance andthe contamination retention capacityhave increased to a large extent. Thismeans that sensitive components areprotected over the long term and thefilter element has a significantly longerservice life. Spiro lock seam support tubes Optimized longitudinal seamFurthermore, even fluids withextremely low conductivity can be Optimized mat structurefiltered without electrostatic discharge Discharge capability Protective envelopetaking place within the filter element, Zinc-free structuredue to a special feature on the filtermesh pack. This is another benefittherefore in the area of operatingreliability and gives HYDAC the cuttingedge in the area of element innovation.The table below summarizes the minimizedpositive effect of the new elementtechnology, Betamicron®4, on the Energy lLife Cycle Cost of your machine or Personnel l l l lsystem. Logistics l l Failure l l l l l Production l l l cost Repair l l l l l Maint enance l l l l l Spare parts l l l l l Waste disposal l More detailed information such as technical specificatons and customer benefits can be found in the brochure "Filter Elements Betamicron®4. For Reduced Life Cycle Cost". E 7.011.0/02.08 9
  4. 4. Causes of contamination What are the causes of contamination and which mechanisms can lead to a rise in the above-mentioned costs? The following illustration indicates possible contamination sources: External contamination Wear (cylinder) Initial contamination of the valve External contamination when system opened Repairs Initial contamination (in the oil) Wear (pump) Origin / formation of If the usually expensive components contamination: are damaged by solid contamination in the hydraulic and lubricating media, Built-in contamination from system faults right up to unplanned components fitted shutdowns can occur. (e.g. valves, fluids, cylinders, pumps, tanks, hydraulic motors, hoses, pipes) The severity of the component damage depends on the material of the contamination, the operating type Contamination produced during V02, must be fitted (round or sharp- assembly of the system, by opening edged) and on the size and quantity of the system, during system operation particles. and during fluid-related system failure The following rule applies: The harder the particles, the greater the Contamination entering from outside component damage and the higher the the system, through: operating pressure the more forcefully the particles become lodged in the - tank breathing lubrication clearance. - cylinders, seals It often goes unrecognized that the majority of these solid particles is Contamination entering the system smaller than 30 µm and they are during maintenance procedures therefore not visible to the naked eye. - system assembly This means an apparently clean fluid can in fact be badly contaminated. - opening the system - filling with oilE 7.011.0/02.0810
  5. 5. Particularly critical are particles whichare the same size as the clearance Size comparisonbetween moving parts.What makes it worse is that hydraulicusers are always stipulating smallerand lighter, high-performancecomponents which reduces the Diameter in µmclearances even further.In the following diagrams you will findthe typical clearances. bearing lubrication film fine/coarse particles human hairOn hydraulic pumps: Gear pump Vane pump Piston pump Dynamic clearance Dynamic clearance Dynamic clearance Tooth to side panel: 0.5-5 µm Vane rim: 5-13 µm Piston to bore: 5-40 µm Tooth point to housing: 0.5-5 µm Vane duct: 0.5-1 µm Valve plate to cylinder: 0.5-5 µmOn valves:Servo valve 1-4 µmProportional valve 1-6 µmDirection control valve 2-8 µm Gap Load, no movementThe operational or dynamic lubricatingfilm is not the same as the machine Slide Ball bearing bearingclearance and is dependent on theforce, speed and viscosity of thelubrication oil.Therefore the lubricating filmseparates the moving surfaces in orderto prevent metal-to-metal contact.Components Clearance (µm)Slide bearing 0.5-100Ball bearing 0.1-3Hydrostatic 1-25 E 7.011.0/02.08ball bearing Load and movement and Ball bearing Lubrication lubrication oil cage film 11
  6. 6. What types of wear are there? 1. Abrasion 1. Abrasion by particles between adjacent moving load surfaces. 2. Erosion by particles and high fluid velocity. 3. Adhesion dynamic from metal-to-metal friction (loss of lubrication film fluid). (µm) 4. Fatigue wear surfaces damaged by particles are subjected to repeated stress. 5. Corrosion by water or chemicals (not covered Effects of abrasion: below). - Changes to tolerances - Leakages - Reduced efficiency - Particles produced in the system create more wear! Abrasion caused by foreign bodies Effects of wear in the case of a hydraulic cylinder: Guide bush Piston seal and bearing Rod seal wear  External oil leakage Guide bush wear  Loss of rod alignment Piston seal wear  Loss of cylinder speed  Loss of holding ability Piston rod seal Piston bearing wear Piston rod wiper  Loss of rod alignment Damaged cylinder pistonE 7.011.0/02.0812
  7. 7. Effect of erosion: 2. ErosionThe high velocity of the fluid forcesexisting particles against the cornersand edges of the system.Other coarse and fine particlestherefore become detached from thesurface and there is a gradual attackon the surfaces in the system. Erosion damage on the cog wheelEffect of adhesion: 3. AdhesionLow speed, excessive load and/or a load loadreduction in fluid viscosity can reducethe oil film thickness.This can result in metal-to-metalcontact, and also possible shearing. cold welded deposit produced by wear Adhesion on ball bearing E 7.011.0/02.08 13
  8. 8. The smallest cracks in the surface are 4. Surface fatigue hollowed out causing material to break off, therefore creating new particles. Particle caught Dented surface This action causes an increase in wear. load load Cracks form as a result Surface cracks, of repeated cycles further particles break off load load chips Surface fatigue on ball bearingE 7.011.0/02.0814
  9. 9. How clean should the fluid be?Classification of the solid particle Particle counting method Particle sizes (Code no.)contamination Automatic > 4 µm(C) > 6 µm(C) > 14 µm(C) particle counterThe classification of solid particle Microscopiccontamination in lubrication and counting --- > 5 µm > 15 µmhydraulic fluids follows ISO 4406/1999.To determine the cleanliness level thesolid particles present in 100 ml fluidare counted, sorted according to sizeand quantity and classified into particleranges.Depending on the method of particlecounting, there are 2 or 3 ranges: ISO Code Particle quantity/100ml Determined using...The ISO Code can be "translated" into (to ISO 4406) from to ...electronic particle countera maximum particle quantity for eachparticle size range with the aid of the 5 16 32 21 / 18 / 15adjacent table. 6 32 64 >4µmc >6µmc 14µmcThis code is specified for each size 7 64 130range. ...microscopic counting 8 130 250The oil cleanliness level determined – / 18 / 15by electronic particle counters is 9 250 500 >5µmc 15µmcexpressed as a combination of 10 500 1000three numbers, e.g. 21/18/15; the 11 1000 2000particle quantity determined by 12 2000 4000microscopic counting is expressed as acombination of two numbers, 13 4000 8000e.g. -/18/15. 14 8000 16000 15 16000 32000 16 32000 64000 17 64000 130000 18 130000 260000 19 260000 500000 20 500000 1000000 21 1000000 2000000 22 2000000 4000000 23 4000000 8000000 24 8000000 16000000 25 16000000 32000000 26 32000000 64000000 27 64000000 130000000 28 130000000 250000000Typical cleanliness level: ISO 22/21/18 ISO 19/18/15 New oil, delivered in drums New oil, delivered in road tanker E 7.011.0/02.08 ISO 17/16/13 ISO 15/14/11 New oil, delivered in mini-container required for modern hydraulic systems 15
  10. 10. Cleanliness requirements Type of system/Area of application/ Recommended cleanliness for lubricating and hydraulic Components class components Systems with servo hydraulics 15/13/10 The cleanliness level in lubricating and sensitive to fine contamination hydraulic systems is determined by the Industrial hydraulics 17/15/12 most sensitive component. l Proportional technology Numerous manufacturers of l High pressure systems components for lubrication, industrial Industrial and mobile hydraulics and mobile hydraulics specify the l Solenoid control valve technology 18/15/12 optimum cleanliness requirements l Medium pressure and low pressure systems 19/16/14 for their components. More heavily Industrial and mobile hydraulics with 20/18/15 contaminated fluids can lead to a low requirement for wear protection significant reduction in service life of those components. Therefore Forced-feed circulatory lubrication on we recommend contacting the transmissions 18/16/13 particular manufacturer for written New oil 21/19/16 recommendations concerning the Pumps/Motors cleanliness of the fluid. l Axial piston pump 18/16/13 In the case of warranty claims, this l Radial piston pump 19/17/13 information is important in order to l Gear pump 20/18/15 reject claims for damages. If the l Vane pump 19/17/14 component manufacturers do not Valves have specific data concerning the l Directional valves 20/18/15 required cleanliness level available, the l Pressure valves 19/17/14 following table can be used: l Flow control valves 19/17/14 l Check valves 20/18/15 l Proportional valves 18/16/13 l Servo valves 16/14/11 Cylinders 20/18/15 The cleanliness levels shown in the Correction factor for the table are based on an operating recommended cleanliness pressure from 100 to 160 bar, a normal Operating pressure less than 100 bar 1 class worse level of ambient contamination and more than 160 bar 1 class better normal system availability. Expected life expectancy up to 10 years no correction Therefore the following criteria must be of the machine over 10 years 1 class better taken into account when determining the required cleanliness levels of the Repair and spare part costs high 1 class better fluid: Stoppage costs due up to 10,000 €/hr. no correction to shutdown over 10,000 €/hr. 1 class better Pilot system 1 class better (system which significantly affects the manufacturing process or cycle)E 7.011.0/02.0816
  11. 11. What kind of filters are there and when are they used?Installation location of filters return line filter pressure filter filtration unit off-line filter air breatherSuction filterSuction filters serve to protect the CONTROLpump from coarse fluid contaminationwhich can cause a sudden pumpfailure.Due to the risk of cavitation of thepump, relatively coarse filter materialswith a filtration rating of > 25 µm areused. SF, SFM, suction filter elementFor this reason, suction filters are notsuitable for ensuring the component Extract from product rangeprotection necessary for theeconomical operation of the system. Suction filter Benefits Remember l Protects the pump against coarse l Fine filtration not possible contamination l Pump must be protected against cavitation (vacuum switch) l Risk of cavitation, particularly at low temperatures (cold start) l To guarantee protection from wear, another filter must be installed E 7.011.0/02.08 17
  12. 12. Pressure filters Pressure filters are fitted after the CONTROL pump and they are sized for the system pressure and the flow rate of the pressure line in which they are installed. Pressure filters are particularly suitable for protecting sensitive components, located directly after the filter, such as servo valves. High pressure filters must withstand the maximum system pressure and the fatigue strength must also be guaranteed owing to the frequent pressure peaks in the system in many cases. Pressure filters must always be fitted with a clogging indicator. Before particularly critical components, only inline filters without bypass valves should be used. Such filters must be fitted with a filter element which must itself be able to withstand higher differential pressures without sustaining any damage. Inline filters The filter housings must withstand the Extract from product range maximum dynamic system pressure. DF 420 bar MFM 280 bar LPF 50 bar Manifold-mounted filters Extract from product range DFZ 315 bar DF...M A 250 bar DFP 315 bar DF...Q E 315 bar Pressure filters Benefits Remember l Filtration directly before the components l More expensive filter housing and which need protection element due to pressure load l Required cleanliness level is l Complex element construction as a guaranteed result of the necessary differential pressure resistance l Pump is not protected l In the case of single filters, the system must be switched off for element changes.E 7.011.0/02.0818
  13. 13. Return line filtersReturn line filters are located in the CONTROLreturn line as an inline filter or as atank-mounted filter on the tank or in thetank. This means that the operating fluidcoming from the system flows back intothe tank completely filtered. Thereforeall contamination particles are filteredout of the fluid before reaching the tank.When selecting the correct filter size,the maximum possible flow rate mustbe taken in account. This correspondsto the area ratio of piston to pistonminus the rod of hydraulic cylindersand can be greater than the flow rategenerated by the pumps.In order to avoid possible foaming ofthe fluid in the tank, make absolutelysure than the fluid outlet from thefilter is always below the fluid levelin all operating conditons. It may benecessary to fit a pipe or a flow ratediffuser in the filter outlet. It is important Return line filtersthat the distance between the floor ofthe tank and the end of the pipe is no Extract from filter rangeless than two to three times the pipediameter.Return line filters can be fitted withbreather filters as additional equipment. RF NF RFN Return line filters Benefits Remember l All fluid flowing back to the tank l In the case of high-value components is filtered a pressure filter must be used in l No system contamination reaches addition the tank l It is advisable to fit a bypass valve l Filter housing and element are l In the case of elements with low excellent value differential pressure resistance, it is possible for the element to burst as a result of multiple pulsations l In the case of single filters, the system must be switched off to change the element l Large filters are required for high flow rates (area conversion for differential cylinders) E 7.011.0/02.08 19
  14. 14. Return line & suction boost filters The return line & suction boost filter RKM was designed primarily for mobile machines with working hydraulics (e.g. extending and retracting cylinders) and drive hydraulics. These filters have the advantage that filtered oil at a pressure of approx. 0.5 bar is supplied to the charge pump of the traction drive, which reduces the risk of cavitation in the charge pump and therefore provides excellent cold start characteristics. In order to maintain the initial load of approx. 0.5 bar at the connection to the charge pump, a surplus of at least 10% between the return line volume and the suction volume is required under all operating conditions. Through the use of a pressure relief valve, when the ∆p reaches 2.5 bar, the oil flows directly into the tank (no bypass to the closed circuit). Return line & suction boost filter If, in addition to the flow from the open circuit, the leakage oil from the hydrostatic drive also goes through the filter, then the permissible pressure of the leakage oil at the filter must not be exceeded (taking into account the pressure drop of the leakage oil lines, of the oil cooler and of the pressure relief valve) to protect the radial shaft seal RKM rings. Return line & suction boost filter Benefits Remember l Finely filtered oil reaches the user unit l It makes sense if under operating (increases the availability) conditions the return line volume l Oil is precharged in the suction is greater than the volume needed on connection (0.5 bar) (prevents the suction side cavitation, less wear) l Replaces several filters (lower fitting costs, only ONE spare element) l Extremely low pressure drop (full filtration at low temperatures) l Various options (thermal bypass valve, multi port)E 7.011.0/02.0820
  15. 15. Offline filterIn hydraulic systems with heavy loads, CONTROLadditional offline filters are usedincreasingly to avoid the accumulationof fine particles.In contrast to main filters, only part ofthe whole flow in the system is filteredby offline filters.Excellent oil cleanliness levels can beachieved through continual filtration,regardless of the operating cycle of themachine. In addition, the main filtersare relieved, meaning that elementchanging intervals can be extended.Offline filter systems should be usedin addition to main filters. In this casethe main filter should be sized as aprotective filter, i.e. filtering less finelyand without a bypass valve. Offline filter Extract from the product range NF Offline filter Advantages l Excellent cleanliness classes l Filtration independent of the system l High contamination retention capacity of filter elements as a result of pulsation- free, low and constant flow through the filter elements l Element change possible without stopping the machine l Cost savings as a result of lower material costs l Less time spent on maintenance l Fewer downtimes l Cost-effective filter elements l Possible to fill hydraulic system l Can be easily retrofitted in systems with insufficient filtration l Dewatering of the fluid is possible l Service life of fluid in the system is extended Generally speaking, offline filters should be installed: l if a high rate of contamination is expected, e. g. on production test rigs, large-scale systems in dusty areas, cleaning systems l when installing a separate cooling circuit l when there are vigorous changes in system flow rate E 7.011.0/02.08 21
  16. 16. Tank breather filters Tank breather filters are one of the most CONTROL important components in filter design. As a result of changes in temperature and of using cylinders or accumulators, the oil level in the tanks of hydraulic and lubrication systems is subject to constant fluctuations. The resulting pressure differential to the ambient is equalized by an exchange of air which means contamination can get into the tanks. The entry of contamination can be prevented by breather filters. Ideally the breather filter should be of at least the same filtration rating as the system filter in the hydraulic circuit. By using breather filters with double check valves, the air exchange between the tank and the ambient can be significantly reduced, minimizing the amount of contamination and dust entering the tank and increasing the Tank breather filter service life of the breather filter. Extract from the product Where there are high temperature range changes and high humidity, water also enters the tank. HYDAC BD filters prevent water from entering and therefore improve the fluid performance. BF ELF/L BD/BDH/BDL Breather filter Benefits Remember l Relieves the system filter by preventing l If the filter is incorrectly sized, damage contamination from entering the tank may occur to the tank and the pump. during tank breathing l High air flow rate l Cost-effective l Environmentally friendlyE 7.011.0/02.0822
  17. 17. Summary FilterFilter location Benefits Remember designationBreather filter l Relieves the system filter by preventing l If the filter is incorrectly sized, damage ELF, BF, BL, contamination from entering the tank may occur to the tank and the pump. BD, ELFL, during tank breathing BT l High air flow rate l Cost-effective l Environmentally friendlyIn the suction line l Pump protection l Coarse filtration only SFE, SF, MF, l Due to the pump suction conditions MFD, LPF, LF, generously sized filters with a low RFL, RFLN, SFM, differential pressure are required SFF, SFR, SFFZ l No protection of components further downstream from pump wear l Unsuitable for many control pumps l Minimal system protection l It is imperative to safeguard the pump against vacuum pressureIn the pressure l Direct protection of the components l Housing and element expensive DF, DFZ, DFNline l Contributes to general cleanliness of since they must be sized for the max. DFP, ILF, the system system pressure LFDK, MDF, l Does not filter contamination from MFM, LPF, LF l Highly efficient fine filter elements can components further downstream MF, MFD, LFM, be used DFM, LFN, LFNF, l Filters pump drive systems l High energy costs LPF, LPFR, LFR, DFF, DFG, DFDK, DF..M A, DF..Q E, HFMIn the return line l Filters the contamination which has l No protection of the pump RF, RFM, RKM, entered the system as a result of l Return line flow rate fluctuations can RFL, RFLD, component friction and worn wipers reduce the filtration efficiency RFN, RFD, RFND, before they can reach the hydraulic tank RFLN, RFLR, l No direct component protection l Low pressure sizing of the filter housing RFMR, RKMR l Large filters may be required, since enables costs to be reduced the return flow is often larger than the l Can be fitted inline or in the tank pump flowOffline l Continual cleaning of the hydraulic fluid, l High investment costs NF, NFD,e. g. cooling also when the system is switched off l Additional space required LF, MFcircuit l Possible to carry out maintenance when l No direct component protection system running l Filtration performance is not affected by flow rate fluctuations and provides optimum service life and performance from the filter elements l Possible to fill tank with filtered oil l Particular cleanliness level can be achieved more accurately and can be maintained. l Possible to integrate fluid cooling easily E 7.011.0/02.08 23
  18. 18. Filter selection Filter efficiency is the most important Protective filter Working filter but not the only factor involved when evaluating the filter design. A filter can l Component protection l Cleaning function be ineffective if it is installed in the l No bypass valve l Flow with least possible pulsations wrong place and if it is given the wrong where filter installed job. l Does not prevent long term wear l Optional with bypass valve When creating a filtration concept, l Filters more coarsely than working filter l Differential pressure indicator is some fundamental rules play an recommended important role. l High differential pressure resistant l Use of low differential pressure For example, the function of a hydraulic filter elements resistant elements is possible filter is always to reduce wear which means it should filter to a finer level than the critical tolerances. Filters should be used with the highest possible flow rate. Suitable seals on cylinders and on breather filters should prevent contamination from entering the system etc. Therefore we can distinguish between protective filters and working filters. Restricting the flow Maximum recommended flow rate in l/min velocity Threaded Suction filter Return line Pressure filter Pressure filter Pressure filter Since specific flow velocities in the connection 1.5 m/s filter up to 100 bar up to 280 bar up to 420 bar connection lines must not be exceeded, 4.5 m/s 4.5 m/s 8 m/s 12 m/s depending on the filter type, we G½ 14 42 42 46 68 recommend only special maximum flow G¾ 23 69 69 74 111 rates. G1 37 112 112 119 178 Here we give guideline values which are based on our experience. G1¼ 59 178 178 182 274 Exceptions, depending on the G1½ 92 275 275 295 443 application, are of course possible and reasonable. Determining the appropriate 25 19/16/13 - 22/19/16 filter element Filtrating rating x 20 18/15/12 - 21/18/15 ( βx(c) >= 200) Depending on the ambient system conditions, the same filtration ratings 15 17/14/11 - 20/17/14 will achieve different oil cleanliness levels. 10 15/12/9 - 19/16/13 The following oil cleanliness classes 5 12/9/6 - 17/14/11 are typically achieved with HYDAC elements: 3 10/7/4 - 13/10/7 10/7/4 11/8/5 12/9/6 13/10/7 14/11/8 15/12/9 16/13/10 17/14/11 18/15/12 19/16/13 20/17/14 21/18/15 22/19/16 Oil cleanliness to ISO 4406E 7.011.0/02.0824
  19. 19. Selection of the appropriate filter materialThe variety of applications of HYDAC filters has given rise to different element models, each specifically optimized for particularrequirements. We are therefore in a position to provide you with the type of element most technically and economicallyappropriate for your special application. The following table outlines the most important filtration media. Our sales team isalways available to help you select the filtration media which is most appropriate for your application. Element designation Construction of filter mesh pack Typical features Synthetic fine filtration materials Betamicron® Multi-layer, supported, pleated filter l High contamination retention BN4HC (20 bar) mesh pack with glass fibre l High rate of particle separation over BH4HC (210 bar) a wide differential pressure range l High resistance to pressure and low rate fluctuations Mobilemicron Multi-layer, supported, pleated filter l High rate of particle separation MM mesh pack with synthetic fibre l Low pressure drop l Sufficient contamination retention l First class filtration in the suction range possible Ecomicron Multi-layer, supported, pleated filter l High rate of particle separation ECON2 mesh pack with synthetic fibre l Low pressure drop l High contamination retention Support tube and end caps in electrically conductive synthetic l Use of first class synthetic materials material which can be easily disposed of l Low weight l Free of steel and iron Lubimicron Multi-layer, supported, pleated filter l Definition of the filtration performance G/HC mesh pack with synthetic fibre according to API specifications Dimicron® Filter discs with at least two filtration l High contamination retention DM layers in synthetic material (500 g/element) l High rate of particle separation l High cleaning effect in the single pass (fuelling stations) Paper Paper Simply supported, pleated, l Cheap element P/HC organic paper l Low level of particle separation and (usually impregnated with phenolic resin) contamination retention (multipass usually not possible) l Low pressure drop l Low pressure stability (bypass absolutely necessary) Stainless steel and wire mesh materials Wire mesh Multi-layer or single-layer, supported, l Protective filter with low filtration or dutch weave pleated square mesh in stainless steel performance and contamination W/HC or dutch weave retention or T/HC Chemicron Multi-layer construction, pleated l All the components in the element and meshpack with sintered stainless are made of stainless steel. metal fibre steel fibre l For element type "Metal fibre V" V these components are bonded with 2-component adhesive (max. temperature 100 °C). l For element type "Chemicron" the element components are bonded without the use of other materials. E 7.011.0/02.08 25
  20. 20. Filter sizing Once the element material, the Use as Filter construction Total initial differential pressure required filtration rating and the filter (with new filter element) construction have been established, the size of the filter can be determined. Working filter Return line filter, 0.15 to 0.2 • Pindicator Here we can assume that the initial Pressure filter with pressure drop of a filter does not bypass valve exceed a specific value, or that it Offline filter, 0.15 to 0.2 bar comes as close as possible to this Inline filter, value (see adjacent table). Separate units Protective filter Pressure filter without 0.3 • Pindicator bypass valve Suction filter 0.04 bar The total pressure drop of a filter (at a specific flow rate Q) consists of the ∆ptotal = ∆phousing + ∆pelement housing ∆p and the element ∆p and is calculated as follows: ∆phousing = please refer to housing curve (see brochure) element gradient coefficient operating viscosity ∆pelement = Q • • 1000 30 Example Maximum initial differential pressure: 1 bar (=0.2 • Pindicator = 0.2 • 2 bar = 0.4 bar) Sizing a return line filter, tank-mounted, type RFM 150, element material Betamicron®4, ∆phousing: ∆pelement: 10 µm filtration rating, (please refer to "RFM" brochure) (for gradient coefficients for Flow rate in the return line: 60 l/min, element 0150 R 010 BN4HC please Operating fluid: ISO VG 46, RFM 90, 150 refer to "Filter Elements" brochure or Operating temperature: 40 °C. "RFM" brochure) Note: At 40 °C this oil has an operating viscosity of approx. 46 mm²/s (always ∆p [bar] 4,0 46 mm²/s take manufacturers data into account). 60 l/min • • = 0.368 1000 30 60 Q [l/min] ∆ptotal = ∆phousing + ∆pelement 0.09 + 0.368 = 0.458 barE 7.011.0/02.0826
  21. 21. How to proceed in practice?If you calculate on the generous side, The size of the filter can be determined with the help ofi.e. choosing the larger filter, this will l Housing and element pressure drop curves in the brochuresprovide a longer service life, and will (= manual filter sizing)probably cost more. But if the sizingis only just adequate, i.e. you select l Filter sizing program Size-ITthe smallest possible filter, you risk (= computer-aided filter sizing)a shorter service life and reduced l Concept creation tool Optimize-ITcomponent protection despite lower (= computer-aided system optimisation)purchase costs.The aim, of course, is to find the mosteconomical filter whilst taking intoconsideration the total system life cycle(reduction of the Life Cycle Cost).Computer-aided filter sizing using Example of filter calculation using sizing software "Size-IT":Filter Sizing Program "Size-IT". Selecting a filter type in the hydraulic circuit diagramSize-IT enables computer-aided filtersizing, specific to the particular systemand application profile.Size-IT is a component of ourelectronic product catalogue onCD-ROM, Filter-IT.We will of course be pleased to sendyou a copy. Alternatively the programis available on our website(www.hydac.com).By using Size-IT, all the calculationswhich in the previous example had tobe carried out painstakingly step bystep, are done fully automatically. Display of element,Possible errors when reading out housing andgraph values are avoided; the time total curve forsaving is considerable. the selected filter type E 7.011.0/02.08 27
  22. 22. Filter calculation according to Example of concept optimization using the electronic tool "Optimize-IT": the expected contamination rate Determining the expected using the concept creation tool contamination for a particular "Optimize-IT" system This electronic tool, called Optimize-IT, is also a component of our electronic product catalogue, but is only available to our filter specialists. Cleanliness classes and achievable service lives for different filter designs can be identified and compared using this tool. Based on the expected contamination, the optimum filter combination and filter size combination can be determined, right down to a specific calculation of the element costs per year. Calculation of the service lives and element costs/year Graph showing cleaningE 7.011.0/02.0828

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