Device and method for supplying lubricating oil to lubricated site

Abstract

The invention relates to a device (1) for supplying lubricating oil to at least one lubricating point (2) of a machine, in particular for producing, processing and treating a fibrous web, the invention relates to a device for cooling a lubricating oil circuit (3, 3.1, 3.2), comprising the following components hydraulically connected by means of lines: a lubricating oil reservoir (4), at least one feed pump (5), a heat exchanger (6) for cooling the circulating lubricating oil, preferably operable with cooling water, and at least one lubricating point (2), the at least one lubricating point (2) is in turn hydraulically connected to the lubricating oil reservoir (4) by means of a line, and lubricating oil flows through the lubricating oil circuit (3, 3.1, 3.2) in the flow direction. The device according to the invention is characterized in that the lubricating oil return line (3.2) comprises an introduction point (11) which is designed to introduce a protective medium, preferably air or nitrogen, into the lubricating oil return line (3.2). The invention also relates to a corresponding method.

Description

[0001] The present invention relates to a device for supplying lubricating oil to at least one lubrication point of a machine, in particular a machine for manufacturing, processing and treating fiber webs, the device comprising the following components hydraulically connected to form a lubricating oil circuit via a pipeline: a lubricating oil storage container, at least one delivery pump, a heat exchanger for cooling the circulating lubricating oil, which can preferably be operated with cooling water, and at least one lubricating point, wherein the at least one lubricating point is in turn hydraulically connected to the lubricating oil storage container via a pipeline, and the lubricating oil flows through the lubricating oil circuit in a flow direction.

[0002] The invention also relates to a method for supplying lubricating oil to at least one lubrication point of a machine.

[0003] Devices of this type are known. Documents DE 10 2020 114 316 A1 or DE 10 2015224 384 A1 describe, for example, a central oil lubrication device. In a paper machine, a plurality of roller bearings are supplied with lubricating oil, for example, by a central oil lubrication device. During the operation of the machine, the operating temperature of the lubricating oil reaches, for example, an operating temperature of 60° C., and absorbs moisture from the environment during operation until the saturation limit of water in the oil is reached. As the temperature rises, the saturation limit also rises. However, the problem that arises from this is that, for example, during operation, water is released when the oil cools down due to changes in operating conditions or especially after the machine is shut down. The released water can cause corrosion of bearing components or other machine elements and thus lead to failure of the entire production line. In order to solve this problem, after the machine starts running, the relative water content of lubricating oil samples at different temperatures is measured in a laboratory, and a reference curve of the relative water content is determined according to the lubricating oil temperature and the type of oil. The sensor is calibrated using these reference curves and the water content is monitored during operation to check whether the permissible limit value for the water content has been reached, which would most likely result in free water forming in the lubricant oil when the lubricant oil cools down. Since the determination of the reference curve is not particularly accurate and the properties of the lubricant oil also change over time, water absorbed in the lubricant oil may still be released when the machine is stopped, which reduces the operating safety. If the lubricant oil is changed, the expensive and laborious procedure of determining the reference curve and programming the sensor must be repeated to calibrate the sensor. The water saturation limit of a determined lubricant oil type is, for example, 300 ppm at an operating temperature of 60° C. and 200 ppm at a stop temperature of 20° C. If the water content of the oil at 20° C. reaches 200 ppm, the relative water content is 100%. Even if the saturation limit has not yet been reached in the operating state at 60° C., the lubricant oil must be replaced or renewed in order to prevent corrosion damage in the lubrication points.

[0004] In order to remove or extract the water absorbed in the lubricating oil from the lubricating oil, a complex, high-maintenance and expensive cleaning device or drying device is usually also provided in the lubricating oil circuit. For example, a water separator is used here.

[0005] Contaminated lubricating oil can also be replaced by new lubricating oil, however, the cost is higher.

[0006] Document DE 35 43 978 A1 also discloses an oil filter device, in particular for an oil filter system of a vacuum pump, in which an oil spray container is flushed with an inert gas.

[0007] Internal combustion engines are known from DE 25 41 616 A1 and US 2003 / 0 121 491 A1 in which the crankcase of the machine is filled with a protective gas, preferably nitrogen, at a low overpressure, which prevents the ingress of oxygen from the air.

[0008] From document KR 10 2003 044 705 A an automatic cleaning system for an oil filter with nitrogen is known, wherein the cleaning system is arranged in the return flow of a lubricating oil system.

[0009] The technical problem to be solved by the present invention is therefore to provide a device and a method for preventing moist air or contaminants from entering the lubricating oil. In addition, the technical problem is to avoid corrosion in the lubricating points of the machine that may be caused by water in the oil. By avoiding possible corrosion, the operating safety can be increased at low cost. The main purpose here is to prevent contamination due to the entry of water at possible entry points.

[0010] The technical problem is solved by the features of the independent claims. A device for supplying lubricating oil to at least one lubricating point of a machine, in particular a machine for producing, processing and treating fibrous webs, is proposed, comprising the following components which are hydraulically connected via lines to form a lubricating oil circuit: a lubricating oil reservoir, at least one delivery pump, a heat exchanger which can preferably be operated with cooling water for cooling the circulating lubricating oil, and at least one lubricating point, wherein the at least one lubricating point is in turn hydraulically connected to the lubricating oil reservoir via a line and the lubricating oil flows through the lubricating oil circuit in a flow direction.

[0011] The present invention is characterized in that the lubricating oil return pipeline comprises an introduction portion, and the introduction portion is designed to enable a protective medium to be introduced into the lubricating oil return pipeline, and the protective medium is air.

[0012] This solution makes it possible to introduce air as a protective medium into at least one lubricating oil return line and to load the lubricating oil return line with an operating pressure or an overpressure relative to the atmospheric pressure and / or a volume flow as far as the lubrication point. As a result, the lubrication points connected to the at least one lubricating oil return line are also loaded with the operating pressure and / or the volume flow. As a result, the at least one lubricating point can be protected from the surroundings from the ingress or penetration of contaminants, such as moist ambient air, steam or foreign substances into the lubricating oil. The lubricating point is usually provided with at least one seal relative to the surroundings, such as a labyrinth seal, through which contaminants can enter during normal operation.

[0013] By introducing the protective medium, a slight overpressure or volume flow, preferably an air flow, can be generated at the lubrication point and its seal, which is sufficient to reduce and / or prevent the ingress of contaminants.

[0014] In practical cases, the introduction site is connected to a protective medium pipeline, and the introduction site and / or the protective medium pipeline comprises a protective medium control valve.

[0015] The at least one lubrication point can include a rolling bearing and / or a sliding bearing and / or a gear transmission.

[0016] In practical cases, the lubricating oil circuit can have at least one heating device for heating the lubricating oil and / or at least one cleaning device for cleaning the lubricating oil. The heating device can include a heat exchanger. The lubricating oil is preferably heated when the machine is restarted from a stopped operating state to an operating state.

[0017] The cleaning device is suitable for removing absorbed water and other contaminants from lubricating oil.

[0018] Viewed in the flow direction, it is advantageous if the lubricating oil supply line comprises a siphon before the lubricating oil flows back into the lubricating oil storage container.

[0019] In practical cases, the introduction point may be arranged before the siphon along the flow direction of the lubricating oil.

[0020] The siphon tube forms a protective medium closure relative to the lubricating oil reservoir. The structural height of the siphon tube or the storage height of the siphon tube has a limiting effect on the possible operating pressure of the protective medium (air) introduced into the return line. The arm length of the siphon tube must therefore be adapted to the desired operating pressure of the protective medium to be introduced.

[0021] In an advantageous embodiment, the lubricating oil circuit can be a lubricating oil circuit which is open to the surrounding environment.

[0022] In practical cases, the lubricating oil return line from the lubricating point to the lubricating oil storage container, preferably from the lubricating point to the siphon, can be a lubricating oil circuit that is partially open to the surroundings. This means that the lubricating oil return line from the siphon to the lubricating point is only partially filled with lubricating oil, preferably filled to a maximum of 75%, in particular 50%, and the remaining portion is occupied by ambient air. This advantageously allows the lubricating oil return line to be simply charged with a protective medium, preferably air. By introducing a protective medium, for example pressurized air, i.e. compressed air, into the lubricating oil return line, an overpressure is generated relative to the surroundings, wherein a relatively low overpressure is sufficient to charge a lubricating point located at a relatively high position (static pressure) in a machine for producing a fibrous web with an overpressure relative to the surroundings.

[0023] In an advantageous embodiment, the lubricating oil return line can include a non-return valve which is arranged to prevent the protective medium from escaping and at the same time to assist the lubricating oil return.

[0024] The non-return valve configures the lubricating oil return line in such a way that the operating pressure cannot escape from the interior to the environment, but prevents an undesired negative pressure from occurring in the lubricating oil return line, for example due to returning oil.

[0025] In practical cases, the lubricating oil return line can include at least one closed ventilation device. The introduction of the protective medium makes it necessary to seal any existing ventilation devices with respect to the environment when modernizing existing equipment. This also has the advantage that the ingress of contaminants through the ventilation device can be prevented.

[0026] The technical problem is also solved by a method for operating a device for supplying lubricating oil to at least one lubricating point of a machine, in particular a machine for producing, processing and treating fibrous webs. The device comprises the following components which are hydraulically connected by lines to form a lubricating oil circuit: an oil storage container, at least one delivery pump, a heat exchanger for cooling the circulating lubricating oil, and at least one lubricating point, wherein the at least one lubricating point is in turn hydraulically connected to the oil storage container and wherein the lubricating oil flows through the lubricating oil circuit in a flow direction.

[0027] According to the invention, a protective medium line and an introduction point are provided in the lubricating oil return line, and thus a protective medium, which is air, is introduced and controlled in the lubricating oil return line at an operating pressure or an excess pressure and / or a volume flow relative to atmospheric pressure.

[0028] In some practical situations, it has proven difficult to set a suitable operating pressure to achieve protection against the influence of moist air, steam and / or contaminants. This situation often occurs in complex branching lubricating oil circuits and is caused by difficult to determine pressure losses in the pipe system.

[0029] Therefore, in an alternative embodiment, a fixed operating pressure is not set at the inlet point, but a defined volume flow of a protective medium, preferably air or a protective medium, is introduced and regulated. This volume flow is monitored and regulated at the inlet point. As a result, the protective medium can flow reliably into the return line of the lubricating oil circuit and a flow directed in the opposite direction to the ingress of moist air, steam or other contaminants is thus present.

[0030] Advantageously, the protective medium is introduced and regulated at an operating pressure of 0.01 bar to 0.1 bar, preferably 0.02 bar to 0.05 bar above atmospheric pressure. Even a low overpressure relative to atmospheric pressure can prevent contaminants from penetrating into at least one lubrication point.

[0031] Advantageously, the protective medium is introduced and controlled with a flow rate which depends on the operating pressure to be set, the size of the lubricating oil circuit and the lubrication points to be supplied.

[0032] In one possible practical case, the protective medium is introduced and controlled with an operating pressure and / or volume flow only after the lubricating oil temperature has reached 40° C. to 80° C., preferably 50° C. to 65° C.

[0033] In one possible practical case, during the startup process and / or when the machine is shut down, the protective medium is introduced and controlled with an operating pressure of 0 bar and / or a volume flow of 0 m 3 / s, ie preferably without pressure and / or flow.

[0034] Further features and advantages of the present invention emerge from the following description of preferred embodiments with reference to the accompanying drawings.

[0035] The only attached picture Figure 1The flow chart of a device 1 for supplying lubricating oil to at least one lubrication point 2 of a machine is shown. The example is a machine for producing, processing and finishing fibrous webs. In such a paper machine, the device 1 supplies lubricating oil to a plurality of bearing points of a roll via a central lubricating oil system, of which only four are shown here for the sake of simplicity. These lubrication points 2 are partially exposed to extreme temperatures and high humidity. In the drying section in particular, the temperature is high, the humidity is high and the environment contains steam. Moisture can accumulate in the lubricating oil until a saturation limit is reached by a condensation process. Since the saturation limit depends on the temperature, water is released during operation and in particular when the machine is shut down due to the cooling of the lubricating oil and this causes corrosion in the bearing points. Other contaminants can also penetrate into the lubricating oil via the lubrication points 2. By Figure 1 The design of the device 1 can eliminate this problem and avoid the ingress of contaminants or the contamination of the lubricating oil.

[0036] The device 1 comprises the following components which are hydraulically connected to form a lubricating oil circuit 3 via pipelines: a lubricating oil storage container 4, at least one delivery pump 5 for generating a lubricating oil flow along the flow direction of the lubricating oil circuit 3, wherein two delivery pumps 5 are provided in the exemplary embodiment, a heat exchanger 6 which can be operated with cooling water for cooling the circulating lubricating oil during operation of the machine, and four lubricating points 2 in the exemplary embodiment. These components are in turn hydraulically connected to the lubricating oil storage container 4 via metal pipelines or hoses. The lubricating points 2 are advantageously supplied with at least one lubricating oil supply line 3.1, and the lubricating oil inflow at each individual lubricating point 2 is controlled via at least one corresponding control valve 16.

[0037] Starting from at least one lubrication point 2, the lubricating oil circuit 3 comprises at least one lubricating oil return line 3.2 per lubricating point 2. In the example described, four lubricating oil return lines 3.2 from the lubricating point 2 lead into a common lubricating oil return line 3.2 after a short line section.

[0038] The lubricating oil return line 3 . 2 leads back into the lubricating oil storage container 4 .

[0039] The lubricating oil return line 3.2 also includes an inlet point 11, through which a protective medium, preferably air, can be introduced into the lubricating oil return line 3.2. The protective medium can be provided by the pressure system of the machine for producing the fibrous web or by a separate compressor. Alternatively, the protective medium can also be stored in a protective medium storage container 20 under overpressure. In addition, the lubricating oil return line 3.2 is connected to the protective medium storage container 20 and / or the compressor and / or the pressure system of the machine for producing the fibrous web via the inlet point 11 and the protective medium line 9. The protective medium line 9 also includes a control or regulation unit, which can regulate the desired operating pressure or the overpressure relative to the surrounding atmospheric pressure and / or the volume flow or flow rate via the protective medium control valve 21. The protective medium control valve 21 can also be designed as a measuring and control unit for the pressure or flow rate.

[0040] The protective medium is introduced into the lubricating oil return line 3.2 at the operating pressure or at an overpressure relative to the atmospheric pressure at the introduction point 11. The introduction point 11 is advantageously located between at least one lubrication point 2 and a siphon 19 contained in the lubricating oil return line 3.2. Furthermore, the introduction point 11 for introducing the protective medium is preferably arranged directly upstream of the siphon 19 in the flow direction.

[0041] The lubricating oil circuit 3 is designed as a system that is partially open to the environment, which means that the lubricating oil return line 3.2 starting from the lubrication point 2 to the lubricating oil reservoir 4, preferably to the siphon 19 contained upstream of the lubricating oil reservoir 4 in the flow direction, is only partially filled with lubricating oil.

[0042] The siphon 19 contained in the lubricating oil return line 3.2 is arranged upstream of the lubricating oil reservoir 4 in the flow direction of the lubricating oil so that the siphon is closed off from the introduced protective medium and the lubricating oil reservoir 4 is not subjected to excess pressure or operating pressure. The construction height of the siphon 19 or the storage height of the siphon 19 has a limiting effect on the possible operating pressure of the protective medium line 9. The arm length of the siphon must therefore be adapted to the desired operating pressure.

[0043] Furthermore, due to the open system in the at least one lubricating oil return line 3.2, no static lubricating oil column with a corresponding static pressure is formed, against which the overpressure of the protective medium set to the operating pressure must act. The protective medium therefore only has to act against the atmospheric pressure of the air in the lubricating oil return line 3.2.

[0044] The lubrication point 2 is, for example, a roller bearing, a plain bearing and / or a gear drive for a drive and / or a bearing for a roller or other rotating part used in a machine for producing a fibrous web. The lubrication point 2 designed in this way is sealed against the environment or surroundings by means of a seal, for example a labyrinth seal. These seals are usually not 100% tight.

[0045] Figure 1 Also shown is a design comprising a non-return valve 18 in the lubricating oil return line 3.2. The non-return valve 18 is arranged in the lubricating oil return line 3.2 such that the set operating pressure cannot escape from the interior to the environment, but prevents an undesired negative pressure from occurring in the lubricating oil return line 3.2.

[0046] In this example, at least one ventilation device 22 is also shown at each lubrication point 2. This ventilation device is included in at least one lubricating oil return line 3.2. Furthermore, this ventilation device 22 is usually included in existing machines for producing fiber webs, thereby avoiding possible negative pressures caused by lubricating oil flowing in the lubricating oil return line 3.2. In the case of renovations and upgrades by means of the invention, in this case, the ventilation device 22 must be removed or sealed off from the environment by appropriate measures, which has the additional advantage that no other contaminants can enter the system through this open point.

[0047] The heat exchanger 6 is connected to a coolant inflow 13 and a coolant return 14. As mentioned above, water is used as a coolant. A heating device 7 is provided after the heat exchanger 6 in the flow direction, and the heating device can also include a heat exchanger. A branch to a bypass line 17 is provided after the heating device for quickly heating the lubricating oil to the operating temperature. The bypass line 17 leads to the lubricating oil storage container 4 after the filter 8 that can be used optionally. The bypass line 17 can realize the heating operation of the device 1 with a smaller lubricating oil circuit 3. In order to achieve the desired temperature, the bypass line 17 also includes a control or regulation unit, which can regulate the heating device through a control valve 16. In an alternative embodiment, a cleaning device 10 can be optionally included in the lubricating oil circuit 3, which is used to remove contaminants, such as absorbed water or other foreign matter. This can additionally prevent the formation of free water in the lubrication point 2 and thus prevent corrosion. Other filters 8 are also provided in the lubricating oil circuit 3 to further remove dirt particles in the lubricating oil.

[0048] Reference numerals list

[0049] 1 Equipment

[0050] 2 Lubrication parts

[0051] 3 Lubricating oil circuit

[0052] 3.1 Lubricating oil inflow

[0053] 3.2 Lubricating oil return

[0054] 4 Lubricant storage container

[0055] 5 Delivery Pump

[0056] 6 Heat exchanger

[0057] 7 Heating device

[0058] 8 Filters

[0059] 9 Protecting medium pipelines

[0060] 10 Cleaning device

[0061] 11 Introduction site

[0062] 13 Coolant inflow

[0063] 14 Coolant return

[0064] 16 Control valve

[0065] 17 Bypass line

[0066] 18 Check valve

[0067] 19 Siphon

[0068] 20 Protective media storage container

[0069] 21 Protective medium control valve

[0070] 22 Ventilation

Claims

1. A device (1) for supplying lubricating oil to at least one lubricating point (2) of a machine, in particular a machine for producing, processing and treating fibrous webs, comprising the following components which are hydraulically connected via pipelines to form a lubricating oil circuit (3, 3.1, 3.2): a lubricating oil storage container (4), at least one delivery pump (5), a heat exchanger (6) for cooling the circulating lubricating oil, which can preferably be operated with cooling water, and at least one lubricating point (2), wherein: The at least one lubrication point (2) is hydraulically connected to the lubricating oil storage container (4) via a lubricating oil supply line (3.1) and a lubricating oil return line (3.2), and the lubricating oil flows through the lubricating oil circuit (3, 3.1, 3.2) along the flow direction, characterized in that the lubricating oil return line (3.2) includes an introduction part (11), which is designed to enable a protective medium to be introduced into the lubricating oil return line (3.2), and the protective medium is air.

2. The device according to claim 1, characterized in that The introduction portion (11) is connected to a protective medium pipeline (9), and the introduction portion (11) and / or the protective medium pipeline (9) comprises a protective medium control valve (21).

3. The device according to claim 1 or 2, characterized in that The lubricating oil circuit (3) has at least one heating device (7) for heating the lubricating oil and / or at least one cleaning device (10) for cleaning the lubricating oil.

4. The device according to any one of the preceding claims, characterized in that The lubricating oil supply line (3.2) comprises a siphon (19) before the lubricating oil flows back to the lubricating oil storage container (4).

5. The device according to claim 4, characterized in that The introduction portion (11) is arranged before the siphon (19) along the flow direction of the lubricating oil.

6. The device according to any one of the preceding claims, characterized in that The lubricating oil circuit (3) is a lubricating oil circuit (3) open to the surrounding environment.

7. The device according to any one of claims 1 to 5, characterized in that The lubricating oil return line (3.2) from the lubricating point (2) to the lubricating oil storage container (4), preferably the lubricating oil return line from the lubricating point (2) to the siphon (19) is a lubricating oil circuit (3) which is partially open to the surrounding environment.

8. The device according to any one of the preceding claims, characterized in that The lubricating oil return line (3.2) comprises a check valve (18) which is arranged to prevent leakage of the protective medium and to assist the return of the lubricating oil.

9. The device according to any one of the preceding claims, characterized in that The lubricating oil return line (3.2) comprises at least one ventilation device (22), and the at least one ventilation device (22) is closed.

10. A method for operating a device for supplying lubricating oil to at least one lubrication point (2) of a machine, in particular a machine for producing, processing and treating fibrous webs, wherein: The device comprises the following components which are hydraulically connected via pipelines to form a lubricating oil circuit (3): a lubricating oil storage container (4), at least one delivery pump (5), a heat exchanger (6) for cooling the circulating lubricating oil, and at least one lubrication point (2), wherein the at least one lubrication point (2) is in turn hydraulically connected to the lubricating oil storage container (4), and wherein the lubricating oil flows through the lubricating oil circuit (3, 3.1, 3.2) in the flow direction, characterized in that a protective medium is introduced into the lubricating oil return line (3.2) via an introduction point (11) contained in the lubricating oil return line (3.2), the protective medium being air, and the protective medium having an operating pressure and / or a volume flow is introduced and regulated relative to atmospheric pressure.

11. The method according to claim 10, characterized in that The protective medium is introduced and regulated at an operating pressure of 0.01 bar to 0.1 bar, preferably 0.02 bar to 0.05 bar above atmospheric pressure.

12. The method according to claim 10 or 11, characterized in that: The protective medium is introduced and controlled with an operating pressure and / or volume flow only after the lubricating oil temperature has reached 40° C. to 80° C., preferably 50° C. to 65° C.

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