FILTRATION UNIT

Abstract

Engine or machine oil filtration unit, the filtration unit being mobile and comprising an oil filtration system (10) including a main oil circulation circuit (11) and at least one particle filter (17, 20), and a particle counting system (25) including a secondary oil circulation circuit (27) and a particle counter (26), the secondary circuit (27) being connected to the main circuit (11) of the filtration system (10), the particle counting system (25) being configured to estimate, during filtration, the number of particles present in the oil, using the particle counter (26), by diverting a portion of the oil from the main circuit (11) into the secondary circuit (27) and to pressurize the oil circulating in the secondary circuit (27) to a minimum of 60 bar. Abstract figure: Figure 1

Description

Title of the invention: FILTRATION GROUP Technical field

[0001] The present disclosure relates to the field of oil filtration units, used in particular for the filtration of oil in public works and transport machinery, such as bulldozers and excavators, and relates in particular to a hydraulic filtration unit with mobile particle counting on site or in the workshop. Prior art

[0002] Public works and transport machinery, just like industrial machines, house oils under pressure in a closed circuit, acting as lubricants and means of transmitting energy. With time and use, these oils become loaded with undesirable solid particles, due for example to the friction of the engine(s) generating metallic particles, to the generation of hydrocarbons, burnt oil residues, or to a dusty environment, particularly when it comes to public works machinery, or to another type of pollution.

[0003] To avoid fouling, wear and even breakdown of the machines caused by oil pollution and despite the presence of oil filters within the machines themselves, and therefore to improve the operation and longevity of a machine, it is necessary to regularly change the oil by carrying out an oil change or to filter it with a filtration unit.

[0004] Changing the oil generates polluting waste for the environment and significant costs because each machine contains a large volume of oil.

[0005] It is therefore preferable, as much as possible, to filter the engine oil using a filtration unit so that it can be reused. In fact, the oil does not deteriorate, it becomes contaminated.

[0006] It is known to carry out on-site filtration of the oil of a machine or machine. A sample of the oil thus filtered is taken. There are two ways of determining the purity of the oil. Either an express diagnosis can be carried out on site, in about ten minutes, which may not be entirely reliable in terms of results, or the sample of oil taken is sent to a laboratory which provides an analysis of the oil within 72 hours. If the sample of oil taken has sufficient purity, the machine or machine can continue to be used. On the other hand, if the oil taken has insufficient purity, then either a new filtration must be carried out followed by a new sample of filtered oil sent to the laboratory, or an oil change in the machine or machine and the replacement of the contaminated oil with new oil is carried out, which is more common.

[0007] There is therefore a need to improve the filtration of engine or machine oil. Summary

[0008] The present disclosure improves the situation.

[0009] A unit for filtering engine or machine oil is provided, the filtration unit being mobile and comprising - an oil filtration system comprising a main oil circulation circuit and at least one particulate filter, - a particle counting system comprising a secondary oil circulation circuit and a particle counter, the secondary circuit being connected to the main circuit of the filtration system, the particle counting system being configured to estimate, during filtration, the number of particles present in the oil, using the particle counter, by diverting a portion of the oil from the main circuit into the secondary circuit, the particle counting system being configured to put the oil circulating in the secondary circuit at a pressure at least equal to 60 bar.

[0010] Thus, a hydraulic filtration unit with mobile particle counting is provided which makes it possible to filter the oil and to estimate, using the particle counter, the number of particles, in particular solid particles, present in the oil being filtered, from the counting of particles in the oil diverted from the main circuit into the secondary circuit. In addition, the pressure greater than or equal to 60 bar in the secondary circuit in which the number of particles is counted makes it possible to have sufficient pressure to degas by compression, that is to say to remove the air bubbles present in the oil before carrying out the counting. Indeed, the air bubbles, when present in the filtered oil, can be counted as solid particles by the particle counter, which distorts the estimation of the number of particles.By applying a pressure of at least 60 bar to the secondary circuit, air bubbles are expelled from the secondary circuit, so that the oil passing through the particle counter is substantially free of air bubbles.

[0011] The estimation of the number of particles present in the oil, by particle size categories, is based on the ISO codes of the manufacturer of the machine or equipment.

[0012] The features set out in the following paragraphs may, optionally, be implemented, independently of one another or in combination with one another:

[0013] The particle counting system may be configured to put the oil circulating in the secondary circuit at a pressure of between 60 bar and 110 bar, preferably between 80 bar and 110 bar, or even between 90 bar and 110 bar. It should be noted that the pressure in the secondary circuit may be adapted according to the viscosity of the oil. In particular, the higher the viscosity of the oil, the higher the pressure will have to be important. The filtration unit is preferably configured to allow pressure adjustment in the secondary circuit.

[0014] Said at least one particulate filter is preferably arranged in the main circuit on the oil circulation path.

[0015] The filtration system may comprise a pump for circulating the oil in the main circuit and the particle counting system comprises a micro-pump for circulating the oil in the secondary circuit. The filtration unit preferably comprises a single motor for operating said pump and said micro-pump. The pump and the micro-pump are then coupled to the single motor. The pump is for example a hydraulic pump with an external gear. The micro-pump may be a micro-pump with an external gear. The pump is preferably coupled to the micro-pump, the assembly of the pump and the micro-pump itself being preferably coupled to the single motor. The pump may be characterized by a maximum pressure of 5 bar. The pump may be characterized by a flow rate, that is to say a volume of oil delivered by the pump in a given time, of between 25 l / min and 35 l / min.

[0016] The micro-pump can be characterized by a maximum pressure of 110 bar. The micro-pump can be characterized by a flow rate of between approximately 0.2 1 / min and 0.4 1 / min.

[0017] An advantage of having only one motor to operate both the main circuit pump and the secondary circuit micro-pump is to limit the volume, mass and cost of the filtration unit, while maintaining sufficient performance. This means that a second motor and an electrical cabinet can be saved.

[0018] The motor may have a power of approximately 0.75 kW. The motor may be a single-phase electric motor (220V).

[0019] The particle counting system may comprise a pressurization valve, in particular mounted in series in the secondary circuit, configured to pressurize the oil in the secondary circuit.

[0020] The particle counting system comprises, for example, a safety valve, in particular mounted as a bypass of the secondary circuit, configured to protect the particle counter in the event of overpressure in the secondary circuit, in particular in the event of pressure greater than 120 bar.

[0021] In one example, the pressurization valve and the safety valve, which are both pressure limiters, are separate and independent of each other. Alternatively, they are integrated into the same drilled block.

[0022] The particle counter can be configured to give an estimate of the number of particles, in particular solid particles, in particular by particle size categories, present in the part of the derived oil and therefore of the oil being filtered. This allows for an immediate count of the number of particles without having to go through laboratory analysis. In addition, the particle counter can be configured to provide information on the number of particles, including via a display screen, in particular according to international standards, such as ISO 4406, NAS 1638, SAE AS 4059.

[0023] The particle counter can be configured to measure water saturation and possibly provide information relating thereto.

[0024] The particle counter may be configured to measure the temperature of the oil and optionally provide said temperature.

[0025] The particle counting system advantageously comprises, on the secondary circuit, a sampling outlet for taking an oil sample. This makes it possible to collect an oil sample and send it to the laboratory for a more precise analysis, for example of the nature and proportions of solid particles according to their size and nature, present in the oil. The laboratory analysis also makes it possible to have the result certified.

[0026] The filtration unit may include a single switch for switching on the particle counter and the motor. Thus, a single user action is sufficient to start and switch off the filtration unit, which makes it easier to use.

[0027] The volume of oil filtered by the filtration group for a given machine is for example between 101 and 4001, in particular approximately 1001. Such a machine may be a public works machine, such as a bulldozer or an excavator, or a transport machine.

[0028] The filtration unit may comprise a chassis mounted on wheels supporting the filtration system and the particle counting system. A user can then handle the filtration unit alone, by maneuvering the chassis. The filtration unit may have a mass of less than 50 kg, for example, in order to facilitate its handling by a technician-operator.

[0029] According to another aspect, in combination with the above, there is provided a method for filtering the oil of a machine or a vehicle, in particular for public works or transport, using a mobile filtration unit as defined above, comprising: - transport the mobile filtration unit near the machine, - connect the filtration system to the machine's oil circuit, - switch on the filtration unit, in particular turn on the filtration unit switch, - carry out filtration with the filtration system, - simultaneously with filtration, carry out a particle count in the oil using the particle counter, - continue filtration until the number of particles estimated by the particle counter is below a predetermined cleanliness threshold.

[0030] A technician-operator can thus easily filter the oil of a machine while simultaneously carrying out a particle count. This avoids having to systematically resort to laboratory analysis to validate the quality of the filtered oil.

[0031] The predetermined cleanliness threshold may be defined by an ISO or NAS standard, in particular the ISO 4406:1999 standard and the NAS 1638 (1964) standard. Such a cleanliness threshold may correspond to a tolerance, generally indicated by the manufacturer for a given machine or device and may include, for example, one or more maximum thresholds for the number of particles larger than different sizes, for example, a maximum threshold for the number of particles larger than 4 pm, a maximum threshold for the number of particles larger than 6 pm and a maximum threshold for the number of particles larger than 14 pm, which corresponds to a maximum ISO code and / or a maximum NAS code. It may be specified by the manufacturer of the machine or device and be specific to it.

[0032] The volume of oil filtered by the filtration group for a given machine is for example between 101 and 4001, in particular approximately 1001. The flow rate of oil in the main circuit is advantageously constant, in particular between 20 1 / min and 50 1 / min, being for example approximately 34 1 / min. The duration of the filtration can be between 5 min and 3 h, in particular between 30 min and 2 h. The duration depends on the quantity of oil to be filtered and the initial level of cleanliness thereof as well as the required cleanliness threshold.

[0033] The method may also comprise: providing information relating to the number of particles, for example on a display screen of the particle counter.

[0034] The method may also include: recording the results relating to the cleanliness of an oil and storing them in a memory.

[0035] The method may comprise: measuring the water saturation and / or the temperature of the oil and possibly providing information relating to the water saturation and / or the temperature.

[0036] The method may comprise: taking a sample of oil from the secondary circuit. This allows the sample thus taken to be sent to a laboratory for further analysis, in particular of the viscosity index, the water saturation, the cleanliness class, the nature and possibly the distribution of the types of particles in the oil, before and / or after filtration and / or after a predetermined filtration time, preferably after filtration. The sample may contain approximately 125 ml of oil.

[0037] The method may include: purging the sampling point before taking the sample.

[0038] The method may comprise: purging the oil remaining in the filtration group at the end of filtration.

[0039] The process may include prior filtration and calibration, in particular according to the usual ISO standards. Brief description of the drawings

[0040] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

[0041] [Fig. 1] shows, schematically and in perspective, an example of a filtration group, in transport position.

[0042] [Fig.2] shows, schematically and in perspective, the filtration group of [Fig.l], ready for filtration, the filtration group being shown without the oil circulation pipe and power cable for the electrical connection.

[0043] [Fig.3] shows an example of an electrical diagram of the filtration group.

[0044] [Fig.4] shows an example of a hydraulic diagram of the filtration group.

[0045] [Fig.5] shows a block diagram of an example filtration process.

[0046] [Fig.6] shows in isolation, schematically and in perspective, an example of a pressure limiter for the filtration group.

[0047] [Fig.7] shows in isolation, schematically and in perspective, another example of a pressure limiter for the filtration group.

[0048] [Fig.8] shows an isolated, schematic and perspective view of an accessory of the filtration group.

[0049] [Fig.9] schematically shows an example of a display screen according to the ISO standard.

[0050] [Fig. 10] schematically shows an example of a display screen according to the NAS specification. Description of the embodiments

[0051] Reference is now made to Figures 1 and 2 showing a mobile filtration group 1, in accordance with an example of implementation of the present disclosure. The filtration group 1 comprises a chassis 2 mounted on two wheels 3, of the all-terrain inflatable type in this example, thus forming a trolley, the chassis 2 comprising a support base 4, a support ladder 5 comprising two uprights 6 whose upper ends form two handles 7 for handling the filtration group 1. The chassis 2 also comprises an axle 8 near the support base 4, on which the wheels 2 are mounted. The filtration group 1 is mobile, which means that its mass, its volume and its configuration allow it to be moved relatively easily by a person. The mass of such a filtration group 1 may be of the order of 40kg-50kg for example.

[0052] [Fig.l] illustrates the filtration group 1 in its transport position, with the uprights 6 inclined and the filtration group 1 resting only on the wheels 3, for be able to be moved.

[0053] [Fig.2] shows the filtration group 1 parked autonomously on the ground, with the uprights 6 vertical, thanks to the parking stability provided by the wheels 3 and the support base 4.

[0054] The filtration group 1 comprises a filtration system 10 configured to filter the oil circulating in a machine, externally thereto. The filtration system 10 comprises a main circuit 11 for circulating the oil comprising at one end a suction pipe 12 for connection to the oil circuit of the machine and for withdrawing the oil from the machine and at another end a delivery pipe 13 for connection to the oil circuit of the machine in order to return the filtered oil to the machine. Between the suction pipe 12 and the delivery pipe 13, the main circuit 11 comprises an oil circulation pipe 14, shown very schematically in [Fig.l] and not shown in [Fig.2] for the sake of clarity of the drawing.

[0055] The filtration system 10 also comprises, as visible in [Fig.4], within the main circuit 11, a pump 15 driven by a motor 16 to manage the circulation of oil in the main circuit 11, with a maximum pressure of approximately 5 bar for example. The motor 16 can be of the three-phase type for continuous and prolonged use.

[0056] The filtration system 10 also comprises, in this example, a main particle filter 17 for filtering the oil circulating in the main oil circulation circuit 11. A clogging sensor 18 of the particle filter 17 is also provided, which can be connected to a clogging indicator 19 configured to give information to the user on the clogging state of the particle filter 17. The information can be in the form of a light indicator which can be of a first color, for example green, when the clogging is satisfactory, for example below a predetermined threshold, and of a second color, for example red, when the clogging becomes unsatisfactory, for example above said predetermined threshold, requiring a change of the particle filter 17. The information can be in another form, for example in the form of a bar indicator indicating the filling level of the filter.The particulate filter 17 may be housed in a filter housing 22 and form an easy-to-change cartridge designed to remove large and small particles, for example filtering particles down to 10 pm or 5 pm or even 3 pm, with a beta ratio efficiency of 200 or even 1000. The particulate filter 17 may optionally remove water present in the oil, in particular when it is undissolved. A safety bypass 60 of the main circuit around the particulate filter 17 is provided in this example. The bypass is provided with a non-return valve 61 and makes it possible to protect the particulate filter 17 from an explosion in the event of a full filter.

[0057] In the example illustrated, the filtration system 10 also comprises a secondary particle filter 20, visible in [Fig. 4], between the suction pipe 12 and the pump 15. It is of course not outside the scope of the invention if there is no secondary particle filter or if it is at another location in the main circuit 11. The secondary particle filter 20 is a suction filter to protect the pump 15.

[0058] The filtration group 1 further comprises a particle counting system 25 comprising a particle counter 26 and a secondary circuit 27 for circulating the oil. As can be seen in [Fig. 4], the secondary circuit 27 is connected to the main circuit 11 of the filtration system 10. The secondary circuit 27 constitutes a circuit derived from the main circuit 11 into which a portion of the oil circulating in the main circuit 11 is diverted for the purpose of counting the number of particles present in the oil, the portion of the oil which is diverted returning after counting from the secondary circuit 27 to the main circuit 11. The secondary circuit 27 is connected at two points to the main circuit 11 to allow said portion of the oil to enter the secondary circuit 27 and to exit the secondary circuit 27, respectively.

[0059] The particle counting system 25 is configured to estimate, during filtration, the number of particles present in the oil, using the particle counter 26, by diverting a portion of the oil from the main circuit 11 into the secondary circuit 27. The particle counting system 25 is also configured to put the oil circulating in the secondary circuit 27 at a pressure at least equal to 60 bar. Such a pressure makes it possible to significantly or even completely reduce the quantity of air bubbles in the oil which could be assimilated to particles by the particle counter 26, which makes it possible to make the counting of particles actually present in the oil, which are not air bubbles, more reliable. Degassing is thus carried out by compression.

[0060] In the example illustrated, the particle counting system 25 is configured to put the oil circulating in the secondary circuit 27 at a pressure of between 90 bar and 110 bar. A pressure gauge 24 makes it possible to measure the pressure in the secondary circuit 27.

[0061] The particle counting system 25 further comprises a micro-pump 28 for circulating the oil in the secondary circuit 27, the micro-pump 28 being driven by the motor 16, which also operates the pump 15. The use of the same motor to operate both the pump 15 and the micro-pump 28 coupled together makes it possible to reduce the electricity required for the operation of the filtration unit 1 and therefore the size of the latter, which in particular makes it possible to make it mobile, i.e. portable. The motor 16 may have a power of 0.75 kW. The pump and the micro-pump may be external gear pumps. It should be noted that the support ladder 5 of the chassis 2 comprises a protective plate 38, especially in aluminum alloy, to protect the terminal board of the motor 16.

[0062] The particle counting system 25 comprises a pressurization valve 29, mounted in series in the secondary circuit 27, configured to pressurize the oil in the secondary circuit 27. It is thanks to this pressurization valve 29 that the pressure in the secondary circuit 27 is greater than 60 bar, improving the quality of the estimation of the number of particles.

[0063] The particle counting system 25 comprises a safety valve 30, mounted as a bypass of the secondary circuit 27, configured to protect the particle counter in the event of overpressure in the secondary circuit 27, in particular in the event of pressure greater than 120 bar.

[0064] The particle counter 26, in addition to counting particles, is also configured in this example to give the user at least one piece of information relating to the number of particles, in particular via a display screen 31, visible in particular in [Fig.l]. The particle counter 26 can measure the water saturation and / or the temperature. The particle counter 26 can give precise indications on the level of cleanliness of the oil and possibly the water saturation and / or the temperature in particular via one or more light indicators, for example on an LCD or LED screen.For example, we can have a green indicator when the test result is good, that is to say that none of the alarm thresholds are exceeded; a yellow indicator when the lower cleanliness limit is exceeded but not the upper limit; a red indicator when the upper cleanliness limit is exceeded; a blue indicator when the upper water saturation limit is exceeded; an indicator in alternating red and blue when the cleanliness limit as well as the water saturation limit are exceeded; a purple indicator when the upper temperature limit is exceeded.

[0065] The particle counter 26 may comprise a connector, for example a USB port, for transferring data to an external device, in particular a computer. The data transfer may also be carried out via a wireless communication protocol, such as Bluetooth or other. The data transfer may take place during and / or after filtration.

[0066] The particle counting system 25 also comprises, on the secondary circuit 27, a sampling outlet 32 ​​for taking an oil sample. This makes it possible to take an oil sample at any time during filtration, in particular at the end of the filtration, in order to send it to a laboratory for a more in-depth analysis, for example an analysis of the nature of the solid particles, the distribution by nature of the particles, an even more precise counting of the number of particles.

[0067] In this example, the filtration group 1 comprises a single switch 33 for the switching on of the particle counter 26 and the motor 16. In the example illustrated, the switch 33 is a switch-disconnector, that is to say that it performs the function of a conventional switch and a disconnector separating the electrical circuit from the power supply, via the control visible in [Fig.l], in order to secure the electrical installation. A switch could also be suitable, as a variant.

[0068] A purge outlet 39 is provided to empty the oil remaining in the filtration group 1 at the end of filtration in one machine, before filtering the oil from another machine.

[0069] The volume of oil filtered by the filtration group for a given machine is for example between 101 and 4001, with a flow rate for example of 30 1 / min. The type of machine whose oil can be filtered using the filtration group 1 is advantageously a public works or transport machine, for example an excavator or a bulldozer, containing approximately 1001 of oil. The treated oils have in particular kinematic viscosities of between 38 cSt and 68 cSt.

[0070] The filtration group 1 is implemented using the following method described with reference to [Fig. 5]. As indicated, the filtration method makes it possible to filter the oil of a machine, in particular a public works or transport machine, using a mobile filtration group 1. First, in a step 40, the mobile filtration group 1 is brought close to the machine, for example by vehicle such as a truck or a van, then, on site, by rolling it on the ground in the position illustrated in [Fig. 1].

[0071] Then, in a step 41, the filtration system 10 is connected to the oil circuit of the machine, using the suction 12 and discharge 13 pipes.

[0072] Then, in a step 42, the switch 33 of the filtration group 1 is activated, which makes it possible to power up the motor 16 and the particle counter 26. Indeed, as visible in [Fig.3] schematically illustrating the electrical circuit of the filtration group 1, the single switch 33, forming a disconnector, makes it possible to power up or power down the motor 16 and the particle counter 26. In this example, a circuit breaker 34 is also present as well as a transformer 35 to change the power supply from a voltage of 100-240V to a voltage of 24V. The filtration group 1 can be connected to a generator or to a mains socket for the 220VAC power supply.

[0073] The next step 43 consists of carrying out the filtration with the filtration system 10. Simultaneously with the filtration, in step 44, a particle count is carried out using the particle counter 26. This consists of estimating the number of particles present in the oil, by measuring those which are present in the part of the oil which passes from the main circuit 11 into the secondary circuit 27. Any particle counting method can be used, for example laser counting. The pressure of at least 60 bar in the secondary circuit 27 makes it possible to reduce or eliminate the number of air bubbles which can distort the particle counts.

[0074] Filtration is continued until the estimated number of particles is lower than a predetermined threshold, for example lower than the ISO and / or NAS code of the manufacturer of the machine (or the machine). To do this, the number of particles is compared, for example continuously or at regular or irregular intervals, to said threshold and if it is lower, then OK in [Fig. 5], filtration is stopped at step 45 by stopping the switch 33. If the number of particles is higher than said threshold, then NOK in [Fig. 5] and filtration is continued until the number of particles is lower than said threshold.

[0075] It is of course possible to display information provided by the particle counter 26 on the display screen 31.

[0076] The method may also include a step consisting of taking an oil sample using the sampling outlet 32, in order to send it to the laboratory, for example for more in-depth analysis than just counting particles, in particular to obtain information on the nature of the particles, their distribution in proportion, etc.

[0077] The present disclosure is of course not limited to the examples which have just been described.

[0078] In the example illustrated in [Fig.6], the pressurization valve 29 and safety valve 30 are separate, as also illustrated in the example of [Fig.4].

[0079] In the example illustrated in [Fig.7], the pressurization valve 29 and safety valve 30 are integrated in the same drilled block. This makes it possible in particular to remove from the filtration unit the pipe 62 connecting the valves 29 and 30 on the hydraulic diagram illustrated in [Fig.4], without changing the latter.

[0080] The filtration group 1 may also comprise a cover for the opening of the tank of the machine to be treated, in order to limit or prevent the penetration of particles, particularly solid particles, into the tank during filtration. An example of such a cover 50 has been illustrated in [Fig. 8]. The cover 50 comprises a circular and substantially flat upper part 51 arranged to cover the opening of the tank of the machine and comprising two openings 52 for the passage, as illustrated, of the suction 12 and discharge 13 rods. The cover 50 also comprises a cone-shaped lower part 53 extending under the upper part 51 and making it possible to guide the suction 12 and discharge 13 rods inside the tank of the machine.

[0081] The table below is shown to which reference can be made to visualize the different categories of oil cleanliness according to the three-digit ISO 4406:1999 standard and according to the NAS standard, in particular the quantity of particles / ml of size greater than 4 pm (“>4 mic”), of size greater than 6 pm (“>6mic”) and of dimension greater than 14 pm (“>14 mie”). Indeed, international standards govern the standards of oil cleanliness at the particle level.

[0082] Group C contains oils with a very good level of cleanliness, which improves the service life of the components of the machine or engine. Group B contains oils of intermediate quality, while Group A contains oils with a level of cleanliness that causes premature wear and breakage.

[0083] [Tables 1] Particles / lOOml ISO 4406:1999 NAS ISO Code > 4 mic > 6 mic > 14 mic 1638 (1964) A 23 / 21 / 18 80000 20000 2500 12 22 / 20 / 18 40000 10000 2500 - 22 / 20 / 17 40000 10000 1300 11 22 / 20 / 16 40000 10000 640 - 21 / 19 / 16 20000 5000 640 10 B 20 / 18 / 15 10000 2500 320 9 19 / 17 / 14 5000 1300 160 8 19 / 16 / 13 5000 640 80 7 18 / 15 / 12 2500 320 40 6 17 / 14 / 12 1300 160 40 - C 17 / 14 / 11 1300 160 20 5 16 / 14 / 11 640 160 20 5 15 / 13 / 10 320 80 10 4 14 / 12 / 09 160 40 5 3

[0084] Figures 9 and 10 show two examples of display screens 31 of the particle counter 26 giving information, in simple mode, relating to the data measured by the particle counter 26.

[0085] In [Fig.9], we see an ISO 55 code, here “21 / 20 / 17” (which means class 21 for particle size >4 pm, class 20 for particle size >6 pm and class 17 for particle size >14 pm) as well as the measured water saturation RH here 39%, and the oil temperature, here 28°C

[0086] In [Fig. 10], we see the NAS 56 code, here “NAS 12”, as well as the saturation in water measured RH here 39%, and the temperature, here 28°C.

[0087] More detailed information may also be displayed on the display screen 31, for example for the ISO standard, for 100 ml, the number of particles measured larger than 4 pm, the number of particles measured larger than 6 pm, the number of particles measured larger than 14 pm, the number of particles measured larger than 21 pm, the number of particles measured larger than 25 pm, the number of particles measured larger than 38 pm, the number of particles measured larger than 50 pm and the number of particles measured larger than 70 pm.For the NAS standard, the display screen 31 can display, for 100 ml, the number of particles of size between 5 and 15 pm, the number of particles of size between 15 and 25 pm, the number of particles of size between 25 and 50 pm, the number of particles of size between 50 and 100 pm and the number of particles of size greater than 100 pm. The flow rate in the secondary circuit 27 can also be indicated, for example 243 ml / min.

Claims

Claims

1. Engine or machine oil filtration unit, the filtration unit being mobile and comprising - an oil filtration system (10) comprising a main oil circulation circuit (11) and at least one particle filter (17, 20), and - a particle counting system (25) comprising a secondary oil circulation circuit (27) and a particle counter (26), the secondary circuit (27) being connected to the main circuit (11) of the filtration system (10), the particle counting system (25) being configured to estimate, during filtration, the number of particles present in the oil, using the particle counter (26), by diverting a portion of the oil from the main circuit (11) into the secondary circuit (27), the particle counting system (25) being configured to put the oil circulating in the secondary circuit (27) at a pressure at least equal to 60 bar.

2. Filtration group (1) according to claim 1, in which the particle counting system (25) is configured to put the oil circulating in the secondary circuit (27) at a pressure of between 60 bar and 110 bar, preferably between 80 bar and 110 bar, or even between 90 bar and 110 bar.

3. Filtration group (1) according to claim 1 or 2, wherein the filtration system (10) comprises a pump (15) for circulating the oil in the main circuit (11) and the particle counting system (25) comprises a micro-pump (28) for circulating the oil in the secondary circuit (27), the filtration group (1) comprising a single motor (16) for operating said pump (15) and said micro-pump (28).

4. A filtration unit (1) according to any preceding claim, wherein the particle counting system (25) comprises a pressurization valve (29) mounted in series in the secondary circuit (27) and configured to pressurize the oil in the secondary circuit (27).

5. Filtration group (1) according to any one of the preceding claims- preceding, in which the particle counting system (25) comprises a safety valve (30) mounted as a bypass of the secondary circuit (27) and configured to protect the particle counter (26) in the event of overpressure in the secondary circuit (27), in particular in the event of pressure greater than 120 bar.

6. Filtration group (1) according to any one of the preceding claims, the particle counter (26) being configured to provide information relating to the number of particles, in particular via a display screen (31).

7. Filtration group (1) according to any one of the preceding claims, in which the particle counting system (25) comprises, on the secondary circuit (27), a sampling outlet (32) allowing an oil sample to be taken.

8. Filtration group (1) according to claim 3 and optionally any one of the preceding claims, comprising a single switch (33) for switching on the particle counter (26) and the motor (16).

9. Filtration group (1) according to any one of the preceding claims, comprising a chassis (2) mounted on wheels (3) supporting the filtration system (10) and the particle counting system (25).

10. Method for filtering the oil of a machine or a machine, in particular for public works or transport, using a mobile filtration unit (1) according to one of the preceding claims, comprising: - transporting the mobile filtration unit (1) close to the machine, - connecting the filtration system (10) to the oil circuit of the machine, - switching on the filtration unit (1), - carrying out the filtration with the filtration system (10), - simultaneously with the filtration, carrying out a particle count in the oil using the particle counter (26), - continuing the filtration until the number of particles estimated by the particle counter (26) is below a predetermined cleanliness threshold.

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