Method and apparatus for the treatment of hydraulic fluids

Abstract

A method and a device (10) for the preparation of a hydraulic fluid (6) are disclosed. The method comprises the steps of: detecting (1) a condition and exceeding (2) a warning threshold for the condition and adding (3) an additive to the hydraulic fluid (6). The device has a sensor (7) designed and configured for detecting (1) a condition and a metering unit (8) designed and configured for adding (3) an additive to the hydraulic fluid (6) when (2) the warning threshold for the condition is exceeded.

Description

Technical FieldThe present disclosure relates to a method and a device for processing hydraulic fluids in hydraulic installations.Most oils are used as the pressure medium or hydraulic fluid in hydraulic systems, which are subject to aging and virtually wear.From the article "COPS-Combined Oil quality and Particle measurement System" (by T. Bley, E. Pignanelli and A. Schutre, published in "2012 Sixth International Conference on Sensing Technology (ICST)", page 561 ff) a measurement system for determining the quality of oil is known. In this case, the oil is passed through a measurement cuvette and, for example, transmitted with infrared light, wherein the light emerging from the measurement cuvette is measured by means of a photodiode.DE 10 2021 201 017 A1 of the applicant discloses a measurement system with which a plurality of characteristic numbers can be obtained which characterize the state of a hydraulic fluid. The indices can be considered together below to provide a statement as to whether or not the hydraulic fluid is still usable. The measuring device is preferably used directly on hydraulic installations or vehicles, for example in order to decide when a change of the hydraulic fluid is necessary.DE 10 2019 217 198 A1 of the applicant discloses a measurement system for monitoring the state of a hydraulic fluid, having a measurement arrangement which has at least two light sources and at least two receivers, which can each be adjusted in a different spectral range. Regions of the infrared and regions of the visible light spectrum are simultaneously detectable by the measuring arrangement. According to the disclosed method, the hydraulic fluid is to be illuminated substantially continuously and an ageing state of the hydraulic fluid is determined.U.S. Pat. No. 6,331,704 B1 discloses a determination of dirt particles in a hydraulic fluid by means of infrared. This is to take place during the running operation of the affected plant.Furthermore, it is known from the prior art that, in the case of high purity requirements, a cleaning medium is continuously added to the hydraulic fluid by means of a system integrated into a hydraulic system, at which cleaning medium dirt particles agglomerate.It is an object of the present invention to further improve the quality or the state of hydraulic fluids. Here, it is also intended to avoid only transitional worsening of the state of the hydraulic fluid. In other words, the state of the hydraulic fluid is always to be kept optimum.This object is achieved by a method according to claim 1 and by a device according to claim 6 and by a hydraulic installation according to claim 10.The method according to the invention serves for the treatment of a hydraulic fluid and has the steps:continuous or periodic or regular detection of a state (parameter), in particular of the state of aging of the hydraulic fluid,exceeding a warning threshold for the state (parameter),supplementing (adding) an additive to be supplemented to the hydraulic fluid, wherein the steps are carried out in the sequence mentioned, and wherein the steps are subsequently carried out again from the front.The corresponding device according to the invention serves for preparing a hydraulic fluid and has a sensor system which is designed and configured for the continuous or periodic or regular detection of a state (parameter), in particular of the state of aging of the hydraulic fluid. Furthermore, the device has a metering unit which, when a warning threshold for the state is exceeded, is designed and configured for supplementing (adding) an additive to be supplemented to the hydraulic fluid. Preferably, said state is determined, in particular measured or calculated, in an automated manner, wherein the determined state is compared with the warning threshold in an automated manner, wherein, depending on the result of the comparison, namely when the determined state exceeds the warning threshold, the additive to be supplemented is dosed in an automated manner to the hydraulic fluid.The invention can significantly extend the service life of the hydraulic fluid in installations (up to the service life filling of the installation). Advantages arise on the one hand from economic savings and also from a reduction in the CO2 emission of the plant due to a reduced requirement for hydraulic fluid.In many applications, the hydraulic fluid is hydraulic oil or lubricating oil with at least one additive present.In the method according to the invention, the detection of the state of the hydraulic fluid is preferably a detection of the proportion of an additive present in the hydraulic fluid, wherein the exceeding of the warning threshold is a falling below a limit value of the proportion of the additive present in the hydraulic fluid. in the corresponding device according to the invention, the sensor system is preferably designed and configured for detecting a proportion of the additive present in the hydraulic fluid. Exceeding the warning threshold is a limit value (of the fraction) of the additive present in the hydraulic fluid being undershot.In the method and apparatus according to the invention, the additive to be added is preferably the same as the additive present.In the method and in the device according to the invention, the additive to be added and the additive present are preferably an antiwear additive. The anti-wear additive is preferably zincdithiophosphate (ZDDP).In the method according to the invention, after the additive to be supplemented has been supplemented (added) to the hydraulic fluid, homogenization of the hydraulic fluid is preferably carried out, or the device according to the invention preferably has a homogenization unit for the hydraulic fluid, or a remaining duration until the additive to be supplemented and / or a lifetime of the hydraulic fluid can / are determined or can be determined from a plurality of states (parameters) detected one after the other, in particular the aging state of the hydraulic fluid, by means of an algorithm.In the method according to the invention, the hydraulic fluid preferably circulates in a hydraulic system (for example in a hydraulic drive), wherein the three to five steps mentioned take place continuously or periodically or regularly during the operation of the hydraulic system.The device according to the invention is preferably further developed to form a hydraulic system (e.g. hydraulic drive), wherein the device can be operated during the operation of the hydraulic system. For this purpose, the device is preferably connected to the closed or open circuit of the hydraulic system.Hereinafter, an embodiment of the present disclosure will be described based on the accompanying figure. FIG. 1 is a flow chart illustrating an embodiment of the method according to the present disclosure; and FIG. 2 shows a hydraulic system including an apparatus according to the present disclosure.The invention is based on a control circuit for regular monitoring 1 of the hydraulic fluid health in hydraulic installations such as lifting mechanisms, transmissions, machines, e.g. motors, etc. If, according to FIG. 1, the state of the hydraulic fluid reaches a critical value 2, an additive is added 3 via a metering unit, so that the performance of the original state of the hydraulic fluid and thus of the hydraulic installations is restored or even improved.In this case, the hydraulic fluid is measured transiently or at short intervals by means of an adequate sensor system 1. This algorithm operates either offline or online as a cloud solution.This algorithm determines which amount of quality-determining additive has been used up by the use. If a critical value is less than 2, the additive concentrate is metered 3 into the hydraulic system via a metering unit and homogenized.In this case, there is also the possibility of deliberately changing (tuning) the hydraulic fluid and of better adapting it to the respective requirements of the hydraulic installation. The invention functions without the prior purification of the hydraulic fluid and during the operation of the hydraulic system, without additional hydraulic fluid volumes.FIG. 2 shows a hydraulic system 4 which is designed as a hydrostatic drive with an open circuit 5, via which a pump P is connected to a motor M. Hydraulic fluid 6 flows under high pressure from the pump P to the motor M via the open circuit 5.The hydraulic system 4 or the open circuit 5 has a tank T. In the region of the tank T, a device 10 is provided which comprises a sensor system 7 and a metering unit 8 and a homogenizing unit 9. The sensor system 7 has a sensor by means of which the proportion of the additive 6 a present in the hydraulic fluid 6 is detected. When the warning threshold is exceeded, the metering unit 8 and the homogenizing unit 9 are activated and the additive added is mixed with the hydraulic fluid 6. The sensor system 7 is then activated again at regular time intervals.More specifically, the method explained with reference to FIG. 1 is carried out with the device 10.List of reference numbers:1 Step Detection 2 Step Exceeding 3 Step Metering 4 Hydraulic system 5 Open circuit 6 Hydraulic fluid 6 a Vorhanden additive 7 Sensor system 8 Metering unit 9 Homogenizing unit 10 Device P Pump M Motor T TankReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 201 017 A1

[0004] DE 10 2019 217 198 A1

[0005] U.S. Pat. No. 6,331,704 B1

[0006] Cited Non-Patent LiteratureCOPS - Combined Oil quality and Particle measurement System" (by T. Bley, E. Pignanelli and A. Schutre, published in " 2012 Sixth International Conference on Sensing Technology (ICST)", page 561ff

[0003]

Claims

Method for preparing a hydraulic fluid (6), having the steps: - continuous or periodic or regular detection (1) of a state (parameter), in particular of the ageing state of the hydraulic fluid (6), - exceeding (2) a warning threshold for the state, - metering (3) or supplementing an additive to be supplemented to the hydraulic fluid (6), wherein the steps (1, 2, 3) are carried out in the order mentioned.Method according to Claim 1, wherein the detection (1) of the state of the hydraulic fluid (6) is a detection of the proportion of an additive (6a) present in the hydraulic fluid (6), and wherein the exceeding (2) of the warning threshold is a falling below a limit value of the proportion of the additive (6a) present in the hydraulic fluid (6).Method according to claim 2, wherein the additive to be supplemented and the additive present (6a) is an anti-wear additive, in particular zincdithiophosphate (ZDDP).Method according to one of the preceding claims, wherein after the metering (3) or supplementing of the additive to be supplemented to form the hydraulic fluid (6), homogenization of the hydraulic fluid (6) takes place.Method according to one of the preceding claims, wherein a remaining duration until the additive to be added and / or a service life of the hydraulic fluid (6) are / is determined from a plurality of successively detected states (parameters), in particular of the state of aging of the hydraulic fluid (6), by means of an algorithm.Device (10) for preparing a hydraulic fluid (6), having a sensor system (7) which is designed and set up for the continuous or periodic or regular detection (1) of a state (parameter), in particular of the ageing state of the hydraulic fluid (6), and having a metering unit (8) which is designed and set up for metering (3) or for supplementing an additive to be supplemented with the hydraulic fluid (6) when a warning threshold for the state is exceeded (2).Device (10) according to Claim 6, wherein the sensor system (7) is designed and configured for detecting (1) a proportion of an additive (6a) present in the hydraulic fluid (6), and wherein the exceeding (2) of the warning threshold is a limit value of the proportion of the additive (6a) present in the hydraulic fluid (6) being undershot.Device (10) according to one of Claims 6 to 7, having a homogenizing unit (9) for the hydraulic fluid (6).Device (6) according to one of Claims 6 to 8, wherein a remaining duration until activation of the metering unit (8) and / or a service life of the hydraulic fluid (6) can / is determinable from a plurality of states (parameters) detected one after the other, in particular of the ageing state of the hydraulic fluid (6), by means of an algorithm.Hydraulic installation (4) having a device (10) according to one of Claims 6 to 9.The hydraulic plant (4) according to claim 10, wherein the device (10) is operable during operation of the hydraulic plant (4).

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