WO2020071977A1

WO2020071977A1 - System for condition monitoring of pressurized system

Info

Publication number: WO2020071977A1
Application number: PCT/SE2019/000015
Authority: WO
Inventors: Roger Gustavsson
Original assignee: Thordab Industri Innovation AB
Current assignee: Thordab Industri Innovation AB
Priority date: 2018-10-03
Filing date: 2019-10-03
Publication date: 2020-04-09
Anticipated expiration: 2021-04-03
Also published as: SE2030245A1; SE546779C2

Abstract

A system (1) for condition monitoring of at least one component of a pressurized fluid system, said pressurized fluid system comprising at least one first tank (3) and at least one first pressurizing device for pressurized fluid (4) such as a first pump and at least one hydraulic component connected directly or indirectly to the tank (3) via at least one leakage line (8). System (1) is intended to be used to monitor the condition of at least one hydraulic component of the pressurized fluid system and to remove at least one contaminant or the like from the pressurized fluid (4) and that the functions of the system (1) are controlled by at least one control system. Condition monitoring is done by the system (1) comprising at least one second tank (6) into which at least one leakage line (8) opens. The system comprises at least one first sensor (15) for sensing at least one first liquid level in the second tank (6) and for the leakage per time unit to be calculated by the control system. The system (1) comprises at least one pump (10) for pressurizing fluid which is passed through at least one filter (13) from the first tank (3) to the second tank (6).

Description

System for condition monitoring of pressurized system

Technical field

The present invention relates to a system for condition monitoring of pressurized fluid systems in accordance with the claims.

Technical background and known technology

Over time, systems for monitoring the condition of a pressurized fluid system, as well as components included in the pressurized fluid system, have been developed in a number of variants. Although systems for monitoring the condition of pressurized fluid systems have been developed, there are problems with these systems. More specifically, problems exist with systems for monitoring the condition of pressurized hydraulic systems of the hydraulic system type.

One of the problems with existing hydraulic systems is the difficulty of monitoring the status regarding; for example, wear in components included in the hydraulic system or in components connected to the hydraulic system.

Another problem with hydraulic systems is caused by how pressure fluid is handled via so- called leakage pipes. The pressurized fluid is usual ly conveyed to the tank via leak pipes without separating particles or other impurities from the pressurized fluid. The reason for this is that a back pressure is not sought in the leak pipes. The problem with the pressure fluid is not filtered is that particles and other things are brought directly to the tank without separating particles and other things in the pressure liquid. These causes wear on components driven by pressure fluid from the hydraulic system. The wear in components causes particles to be added to the hydraulic system. Studies conducted indicate that in hydraulic systems, up to about 30 percent of the particles in the hydraulic oil are due to wear in components of the hydraulic system.

Furthermore, there are problems in that systems for monitoring of conditions in hydraulic systems cannot effectively predict the cost of wear and the like in these. The difficulty is that it is difficult to detect _^whether the hydraulic system w^rorks efficiently or not. In case of overcapacity in the hydraulic system, problems with wear and increased flow in leakage line can be hidden by said overcapacity. It is only when the leakage becomes as large as the overcapacity that the problems become apparent. Another problem with pressurized fluid systems of the hydraulic system type is caused by the volume of pressurized liquid and the volume of air in the hydraulic system tank or tanks varying. This means that air needs to be brought into the respective out of the tanks. With the air, particles come into the tank, which in turn is transferred to the hydraulic oil. Studies conducted indicate that in about 30 percent of particles in hydraulic oil originate in the air that moves in and out of the hydraulic tank in the event of volume changes in the hydraulic tank.

Equipment for dehumidifying air that comes into contact with hydraulic oil is already known. For example in the Swedish patent application SE 1400166-3, applicants for the present patent application describe a variant of a dehumidifier which dehumidifies air in a hydraulic tank and the air which is introduced into the hydraulic tank. The design differs from the design examined as it is not a system for monitoring the condition of a hydraulic system.

In patent application SE173G295-1, of the applicant to the present patent application, discloses a variant of a dehumidifying device whi ch is intended to separate moisture from air in a hydraulic tank and the air which is introduced into the hydraulic tank in connection with volume reduction in the tank. The design differs from the design examined as it is not a system for monitoring the condition of a hydraulic system.

A further problem is caused by the hydraulic tank being pressurized to prevent particles from entering via air. This type causes problems with leakage lines which shoul not be

pressurized.

A further problem with the known pressurized systems is that they only filter out particles or moisture without an effecti ve condition monitoring of hydraulic systems.

The object of the present invention is to eliminate or substantially reduce at least one of the aforementioned, or in the following description, problems with existing types of system. The object is solved by a system as well as a method of using the system in accordance with the present patent application. Brief description of figures

In the following detailed description of the present system, references and references to the fol lowing figures wi ll be made. Note that the figures are schematic and some parts of the system may be omitted which will be apparent to one of ordinary skill in the art in which the syste is comprised.

Figure 1 shows an illustrative system according to a first embodiment of the present patent application.

Figure 2A shows in a hydraulic diagram a system in its first embodiment.

Figure 2B shows in a hydraulic diagram a first alternative embodiment of the system.

Figure 3A shows in a hydraulic diagram a second alternative embodiment of the system.

Figure 4 shows in a hydraulic diagram a third alternative embodiment of the system.

Figure 5 shows an alternative embodiment of a system according to the present patent application.

Figure 6 shows a further embodiment of the present system.

Figure 7 show's a further embodiment of the present system.

Figure 8 shows a further embodiment of the present system.

Figure 9 shows a further embodiment of the present system.

Figure 10 show's a further alternative embodiment of the present system.

Detailed description of the invention

With reference to the figures, a system ! for condition monitoring of at least one pressurized fluid system will be described in more detail. The pressurized fluid system in the exemplary' embodiments comprises at least one hydraulic system 2. The system 1 for monitoring hydraulic system 2 is intended to be connected to, or integrated with, any type of existing hy draul ic system 2. The design of the hydraulic syste 2 can vary' to a very large extent in the preferred embodiments, system 1 is also intended to completely or partially reduce the presence of at least one contaminant in the pressurized liquid system. Contaminants refers to substances, particles or the like that are not sought in the pressurized liquid. By contamination for example, is meant water, particles, or air or anything else that is not sought in the pressurized liquid.

Referring to Figure 2, it is shown that the hydraulic system 2 comprises at least one first tank 3, main tank, hydraulic tank or the like. The tank 3 comprises at least one inlet and a partial volume respectively of the pressurized liquid system pressure fluid 4. The tank 3 further comprises a partial volume of air 5. The volume of air 5 in the tank 3 varies depending on the volume of pressure liquid in the tank. The pressurized fluid is pressurized via at least one first pump, not shown in figures, and is passed through the piping system into the hydraulic system 2. In order to clarify the system 1 construction, parts of the hydraulic system 2 in the figures are omitted. Thus, for example, components driven by the hydraulic system 2 are not included in the figures.

The hydraulic system 2 monitoring system 1 comprises at least one second tank 6. The second tank comprises at least one inlet and at least one outlet. The tank 6 comprises a volume of pressurized fluid 4 and a volume of air 5. The volume of air 5 in the tank 6 varies depending on the volume of pressurized fluid 4 in the tank. The second tank 4 is standalone but communicates with the first tank 3 via at least one line 7 such as pipes, tubing or the like. In an alternative embodiment, the second tank is integrated with the first tank 3. Pressure fluid is supplied to the second tank 4 from at least one leakage line 8 from a hydraulic component such as motor, pump or other hydraulic component. In the illustrated system of the figures, pressure fluid is combined from at least one first leakage line 8a, at least one second leakage line 8b and at least one third leakage line 8c to the leakage line 8 The advantage of the system 1 comprises at least one second tank 6 in which at least one leakage line results in that no counter pressure or substantially low back pressure exists in the leakage line or leakage lines.

The system 1 consists of a subsyste which is connected to or integrated with the hydraulic system. The system comprises at least one drive unit such as, for example, a motor 9 which drives at least one pump 10, such as a hydraulic pump. The pump 9 sucks pressure fluid 4 from the second tank 6 via at least one suction line 1 1. The pump 6 pressurizes pressure fluid 4 and for the pressurized pressure fluid 4 via at least one pressure line 12 to at least one filter 13. The filter 13 Is in the exemplary_' embodiment a particle filter in which particles are filtered away from the pressure fluid 4. From the filter 13, the pressure fluid 4 is passed directly or indirectly via at least one conduit 14, pipe, hose or the like to the first tank 3. By the above-mentioned process, filtration of the pressurized liquid 4 is effected by the separation of particles in the filter 13. The result of the filtration is that the pressurized liquid 4 comprises a smaller amount of particles after the filtration. A smaller amount of particles in the pressure flui 4 increases the service life of components included in the hydraulic system.

The system 1 comprises at least one subsystem for measuring the leakage volume per unit of time. This can be done in several ways. For example, by using at least one first sensor 15, or the like. In the exemplary embodiment, this is done by the second tank 6 comprising at least one first sensor 15 and at least one second sensor 16. The first sensor 15, the sensor, is located at a first distance, height, from the bottom 17 of the second tank 6. The second sensor 16 is located at a second distance, height, from the bottom 17 of the second tank 6. The first sensor

15 consists of an "on-off’ sensor of the appropriate type. This detects when the liquid level 18 reaches the first level. The second sensor is an on-off sensor of the appropriate type which detects the liquid level on a second level 19. In alternative embodiments, the sensors 15 and

16 may be of an analog type or some other suitable type of sensor. The flow' in leakage lines is calculated based on how long it takes to fill the tank 6 between the level 18 of the first sensor and the level 19 of the second sensor. Through the design, leakage per unit of time can be determined, that is, flow per unit of time.

In alternative embodiments, the system for measuring the flow^? in leakage lines ma use another type of sensor suitable for the purpose in the monitoring system. The sensor in the monitoring system may be of another type of sensor or the like, which senses the flow per unit time in the leakage line constituting an alternative embodiment of the present invention.

Referring to Fig. 2B, a first alternative embodiment of the system 2 shown in Fig. 3 is shown, the system comprising at least one first particle counter 20, particle sensor, particle sensor or the like. In the exemplary embodiment, the particle counter 20 is connected to the pressure line between the pump 10 and the particle filter 13. In the first embodiment, the first particle counter 20 may be positioned at another suitable position in the system 1. The first particle counter 20 is, for example, an optical sensor or another suitable sensor for the purpose.

Furthermore, it is conceivable that the first particle counter 20 is of a magnetic type.

With reference to Figures 3 A, 3B and 5, it is shown that the system in embodiments further comprises at least a first regulating valve 21 intended to enable one to control the flow through the pump 6, the filter 9 and the particle counter 20, the particle sensor. The first regulating valve 21 is connected via at least one conduit 22, pipe, hose or the like to the tank 3 and at least one conduit, tube hose or the like to the tank 6. By operating the first regulating valve 21 , pressurized liquid which is purified can be taken from the tank 6 or the tank. 3. By means of the first regulation valve 21, a so-called bypass circuit is created where purification of the pressure fluid in the tank 3 can take place during a time when a measurement of leakage in leakage pipes is made, that is during the time as the volume, the measuring volume, between sensors 15 and 16 in tank 3 is filled. During purification, the control system controls the pumped flow so that the purification of the pressure fluid in the particle filter preferably takes place with an optimum or substantially optimal flow for the particle filter.

Referring to Fig. 3B, a second alternative embodiment of the system is shown which comprises at least a third sensor 23 for sensing at least one pressure fluid parameter in the main tank 3. For example, the sensor 23 can sense the functional content of the pressure fluid, sense the temperature or sense another parameter or other parameters. The figure does not show pumps and pipes, hoses for conveying the pressure fluid, such as the hydraulic oil, from and to the main tank via components and the like driven by the pressure fluid. The system in accordance with the embodiment further comprises at least a first gear valve 21 intended to enable the flow to be controlled via the pump 6, the filter 9 an the particle counter, the particle sensor.

Referring to Figures 4 and 5, an alternative embodiment of the system is shown. In that embodiment, the system 2 comprises a dehumidifying device 24 which dehumidifies the air 5 in at least one of the tanks 3 or 6. The dehumidification takes place in connection with volume changes in the tank 3 and or 6 and the air is discharged from the tank 3 and / or 6 and introduced in the respective out of the tank 3 and / or the tank 6 via the dehumidifying device 24. The dehumidifying device 24 communicates via at least one conduit 25 with the tank 3. The dehumidifier 24 steel, via conduit 26, contacts the second tank 6. In a preferred embodiment, the system 1 comprises at least one expandable body 27, balloon, to which air from the hydraulic tank is brought in conjunction with an increase in the hydraulic oil level in the tank and from which air is introduced at a decrease in the hydraulic oil level in the tank. Through the construction, dehumidification of the air at flow occurs both in at least one of the tank 3 and the second tank 6 and out of at least that tank 3 and the second tank 6, that is, in both directions. In an alternate embodiment, the respective leakage line opens directly or indirectly into the second tank 6. At least one of the leakage lines is provided with at least one flow sensor in alternative embodiments 28 In the exemplary embodiment of Figure 5, each leakage line is provided with at least one flow sensor 28 or the like. The design makes it possible to measure the flow in at least one second leakage line. Furthermore, it is conceivable that the respective leakage line comprises at least one particle counter each.

Referring to Fig. 6, it is shown that the system 1 comprises at least one second tank 6 and at least one third tank 29. In the embodiment, the respective leakage line comprises at least one second regulating valve 30. The second regulating valve 30 controls the flow to either the second tank 6 or the third tank 29. At least one leakage line is connected to the third tank 29. In the exemplary embodiment, at least one first leakage conduit 8a, at least one second leakage conduit 8b and at least one third leakage conduit 8c are connected to the third tank 29. With at least one second gear valve 30a and a second gear valve 30b in the exemplary embodiment, a choice can be made if the flow of leakage lines 8a or 8b per unit of time to be analyzed. In the exemplary embodiment, the embodiment includes the alternating valves 30a, 30b and 30c, a choice can be made about which flow of leakage lines 8a, 8b or 8c per unit of time to be analyzed.

In a preferred embodiment of tanks 3 and 6, at least one of these tanks 3 or 6 has a bottom which contains a sub-surface which is angled relative to the horizontal plane (when using the system). The bottom consists of at least one first sub-surface 31 and at least one second sub surface 32 The second sub-surface 32 is angled with respect to the first sub-surface 31. The construction means that sedimentation of particles and the like in the pressure fluid in the tank tak

Referring to Fig. 7, there is shown a further alternative embodiment of the present patent application which includes at least one vacuum pump 33, undersupply unit or the like, which puts the tank 28 and / or the tank 6 under vacuum. With the vacuum pump 33, the pressure liquid is degassed. In the exemplary embodiment, the construction comprises at least one conduit 34 which connects the vacuum unit 33 to the tank 28. If the oil has a sufficient heat, the underpressure means that water in the pressurized liquid can boil and a degassing thereof takes place.

Referring to Fig. 7, an embodiment of the system 1 is shown whi ch comprises at least one heater 34, the heat release device with which the pressure fluid in the system in the tank 28 and / or the tank 6 is heated . The heater can be of different types. The heater is used in cases where the pressure fluid is cold and needs to be heated in order for an effective degassing of the pressure fluid to take place. Preferably, both the pressurized liquid is heated and it is pressurized. However, this does not exclude that only one of the heat or vacuum is used.

Referring to FIG. 8, the system is shown in accordance with FIG. 7, but this also includes at least one dehumidifying device 24 in accordance with the prior art. The system 1 may further comprise at least one expandable body according to previously described. The system comprises at least one control system 35 which includes at least one control unit 36 with which monitoring and control of the system's functions takes place. The control system controls the functions of the system. The control system preferably also logs the state, status, of the hydraulic system. In the illustrated embodiment, the controller comprises at least one display and at least one communication unit. The control system also communicates with at least one external device. The communication is preferably wireless, but in alternative embodiments can be via wires placed on the part located at the bottom of the tank.

Referring to Fig. 9, a variant of the system according to Fig. 8 is shown where the vacuum unit 33 is connected to the expandable body. The embodiment comprises at least one valve through which the flow to and from the expandable body can occur. The embodiment shown in Figure 9 constitutes a closed system or substantially closed system.

Referring to Fig. 10, an alternative embodiment of the system comprising a first sensor, meter or the like is shown. For example, the sensor may consist of a first sensor. With the construction, thus, the measurement of the flow per unit of time is achieved by a sensor that senses a first level and one that senses a second level.

With the present system 1 , it is possible to calculate the power loss in one or more

components of the hydraulic system 2. This is preferably calculated by the following formula:

(Pressure x Leakage) / 600 ^:= Power loss

This assumes that the pressure in the hydraulic system is measured at the component or that the pressure is estimated at the component or components. The leak in liters per minute is measured with equipment described in this patent application. The pressure of the leakage volume is 0 or substantially 0. In the detailed description of the present system 1, details and subsystems may be omitted which will be apparent to one skilled in the art to which the system 1 relates. Such obvious details and subsystems are included to the extent required to obtain a satisfactory function for the present system 1.

Although some preferred embodiments of the system have been described in more detail, the scope of the invention may relate. All such modifications and variations are considered to fall within the scope of the appended claims.

Advantages of the invention

The present invention provides a number of advantages. The most obvious is that at least one of the problems described in the background with existing designs is eliminated or

substantially reduced.

With the present system, a state monitoring of a hydraulic system allows at the same time a treatment of the pressure fluid. By treatment, for example, is mean t the separation of particles, dehumidification, degassing and more.

Claims

1. A system (1) for monitoring at least one component of a pressure fluid system, said pressure fluid system comprising at least one first tank (3) and at least one first pressure-creating device for pressure fluid (4) such as a first pump and at least one hydraulic component connected directly or indirectly to the tank (3) via at least one leakage line (8), said system (1) suitable to be used to monitor the state of at least one hydraulic component of the pressure fluid system as well as remove at least one pollutant or similar from the pressure fluid (4) and the system’s (1) functions are controlled by at least one control system characterized in that monitoring occurs by the system (1) being comprised of at least one second tank (6) into which at least one leakage line (8) runs, and that the system comprises at least one first sensor (15) for sensing at least one first liquid level in the second tank (6) and that the leakage per time unit is calculated by the control system, and that the system (1) comprises at least one pump (10) that pumps pressure fluid via at least one filter (13) from the first tank (3) to the second tank (6).

2. A system (1) in accordance with claim 1 characterized in that the system comprises at least one first sensor (15) for sensing at least one first level of liquid in the second tank (6) and at least one second level of liquid in the second tank (6)

3. A system (1) in accordance with one of the previous claims 1 or 2 characterized in that the system (1) comprises at least one particle sensor (20).

4. A system (1) in accordance with one of the previous claims 1 or 2 characterized in that each respective leakage line is equipped with a particle sensor (20).

5. A system (1) in accordance with at least one of the previous claims characterized in that the system (1) comprises at least one regulating valve (21) between the tank (3) and the pump (10) and that the regulating valve is connected to the second tank (6) via at least one conduit.

6. A system (1) in accordance with at least one of the previous claims characterized in that each respective leakage line includes at least one regulating valve (21) and that the system comprises at least one third tank (29) and that each respective regulating valve (21) allows for the flow via the leakage line to either go to the second tank (6) or to the third tank (29).

7. A system (1) in accordance with claim 6 characterized in that the system (1)

comprises at least one vacuum pump (33) with which the pressure fluid in the third tank (29) or the second tank (6) is pressurized.

8. A system (1) in accordance with one of the previous claims 6 or 7 characterized in that the system (1) comprises at least one heater (34) which heats the pressure fluid in at least the second tank (6), alternatively the third tank (29).

9. A system (1) in accordance with one of the previous claims characterized in that the control system comprises a function for calculating energy loss in at least one component of the hydraulic system.

10. A system (1) in accordance with one of the previous claims characterized in that the system comprises at least one dehumidifying device.

11. A system (1) in accordance with one of the previous claims characterized in that at least one leakage line (8) is equipped with a flow sensor (28).

12. A system (1) in accordance with one of the previous claims characterized in that the pressure fluid system consists of a hydraulic system (1).

13. A system (1) in accordance with claim 12 characterized in that the hydraulic system consists of a closed system.

14. A method for use of the system in accordance with at least one of claims 3 to 11 characterized in that the system (1) is connected to, or integrated with a pressure fluid system, and that pressure fluid from at least one leakage line flows to the second tank (6) after which a measurement of the flow per time unit is calculated in at least one leakage line, after which the pressure fluid flows from the second tank (6) to a particle sensor after which the pressure fluid is purified by at least one filter (13) after which the pressure fluid flows to tank (3).

15. A method for use of the system in accordance with claim 12 characterized in that the pressure fluid from the first tank (3) flows via the pump when pressure fluid from the second tank is not pumped via the pump to the filter and that the flow is controlled by a control valve.

16. A method in accordance with claim 15 characterized in that degassing of the pressure fluid occurs via at least one vacuum pump (33) and, if necessary, by at least one heating device (34).