Device and method for operating a conveying system for conveying a lubricant

Abstract

Device (4) for operating a conveying system (2) for conveying a lubricant, comprising: a sensor interface (16) for receiving an information signal containing information about an ambient temperature in an environment of the conveying system (2); and a control interface (20) for outputting a control signal for the conveying system (2), which causes a change in a conveying characteristic of the (8) conveying system (2) which includes a piston pump used for conveying the lubricant, depending on the information signal, wherein the control signal causes a reduction in the number of pump strokes of the piston pump (8) by adjusting the suction time by a defined stop in a suction position of the piston pump when the information about the ambient temperature indicates a reduction in the ambient temperature.

Description

[0001] Exemplary embodiments of the present invention relate to a device and a method for operating a conveying system for conveying a lubricant.

[0002] Applications requiring the simultaneous lubrication of one or more mechanical components or machines with a lubricant are diverse. In systems where a lubricant is distributed from a central reservoir to the components, a distinction can be made between consumption lubrication and circulating lubrication. In consumption lubrication, the lubricant is supplied to the component once and consumed there, or disposed of after use. In circulating lubrication, a lubricant circulates in a closed loop and, possibly after reprocessing, is repeatedly supplied to the component requiring lubrication within the loop.

[0003] To pump the lubricant from the central reservoir to the individual lubricant distributors, which direct the lubricant to the lubrication point at the distributor outlet via a so-called main line, different pump systems are used, including multi-circuit pumps, single-circuit pumps or piston pumps.

[0004] When planning a conveying system for a lubricant, or when planning the central lubrication system, the most unfavorable constellation of relevant functional and environmental parameters expected in real-world operation is typically used as the basis. For example, if viscous fluid media such as greases or similar substances are used as lubricants, the design is usually based on the minimum temperature expected during normal operation, as the pumpability of the lubricant is at its worst at this temperature. This means that flow properties of the media or lubricants being conveyed, which change depending on the environmental conditions, are not taken into account. This, in turn, leads to a mismatch in functionality or the conveying system for the majority of the operating time. For example, if the pump runtime or...Assuming the worst-case scenario for the delivery rate, too much lubricant is delivered under normal operating conditions, leading to over-lubrication of the connected bearings and lubrication points. This reduces the service life of the bearing or system. Excessive lubrication, i.e., the presence of too much lubricant, results in, for example, a temperature increase in the bearing due to the increased rolling work. Besides the expected reduction in service life, such over-lubrication naturally leads to unnecessarily high lubricant costs and, in the case of consumption lubrication systems, to ecologically and economically unsound situations, as more lubricant is consumed than actually required.

[0005] A conveying system not designed for the worst-case scenario can also lead to a reduction in the service life of the lubricated components. The delivery volume of pumps or pump units commonly used for conveying is primarily determined by geometric parameters, such as the shape of the conveying chamber, the number of chambers, and the time the pump requires for a complete delivery stroke or for a delivery stroke with an intervening pause. During the pause, when no active delivery stroke is taking place, the conveying chamber must be completely filled with lubricant, which is why it is usually connected to a lubricant reservoir via a suction port. The filling of the conveying chamber depends, among other things, on the viscosity of the lubricant, which in turn can be affected by temperature or other environmental parameters.In addition to the geometric parameters, the time available to fill the suction chamber naturally also depends on the stroke frequency or the number of rotations and chambers at which the pump is operated. If the operating condition changes, for example to a very low ambient temperature, different fill levels of the pumping chambers can occur with a static design; that is, the available refilling time may not be sufficient to completely fill the pumping chamber for a given viscosity. This leads to fluctuations in the flow rate.

[0006] The fill level of the pumping chamber would then be lower than the percentage (100%) used as the basis for the design of the pumping system. If this percentage falls below 100% of the target value under unfavorable operating conditions, it can, for example, lead to an insufficient supply of lubricant to the bearings, resulting in friction. A change in the lubricant's condition during operation, which can be caused, for example, by the influence of ambient temperature, can thus lead to a change in the lubricant's viscosity and consequently to an insufficient supply to the bearings, resulting in a reduction in the service life of the lubricated components.

[0007] German utility model DE 20 2010 016 721 U1 proposes that a lubricant pump additionally have at least one heating element which can be operated as needed via the control unit assigned to the drive and / or via a separate control unit. The heating can be used selectively whenever a malfunction of the lubricant pump is due to lubricant hardening at low temperatures.

[0008] Publication DE 20 2008 000 748 U1 discloses a lubricant pump for conveying lubricant to a plurality of lubrication points, wherein the lubricant pump comprises a first housing section including a lubricant reservoir, a second housing section in which a plurality of pump elements are accommodated and driven by an eccentric rotating on a shaft, and a third housing section for connecting interchangeable different drive units.

[0009] Publication EP 0 845 631 A1 relates to a lubricant dispenser with a cylindrical housing consisting of a lower housing part and a screw-on upper housing part, with an electric motor drive, an actuating piston, and batteries. According to the invention, the electric motor drive has a substantially cylindrical drive housing containing an electric motor and a reduction gear. An interchangeable insert is arranged in the housing, comprising a cylindrical sleeve and a base mounting plate for the drive housing of the electric motor drive, and containing a receiving space for inserting the batteries.

[0010] The insert is placed in the lower housing part and has an outer collar that can be clamped between the lower housing part and the upper housing part.

[0011] Publication DE 38 18 256 A1 relates to a method for adjusting the lubrication time of a lubricant pump driven by a motor with fluctuating rotational speed within a cycle time. To ensure that the necessary quantity of lubricant is supplied to the lubrication points despite such fluctuations, the lubrication time is adjusted depending on the number of revolutions made by the pump. Furthermore, a device for carrying out the method is disclosed, comprising a measuring device for recording the number of revolutions of the lubricant pump or the drive shaft of the drive motor, as well as an associated switching device.

[0012] Publication DE 102 23 466 A1 discloses a pump, in particular for lubricating oil of internal combustion engines or for gear oil, with adjustable stroke volume and with at least one actuating means, in particular a vane pump.

[0013] Publication DE 10 2010 019 007 A1 discloses a lubrication circuit for an internal combustion engine, comprising a lubricant pump connected to a reservoir on the suction side and to a distributor on the pressure side. At least one lubrication point is connected to the distributor and a return line leading to the reservoir. An electronic control unit is provided to regulate the output pressure of the lubricant pump based on the lubricant temperature.

[0014] Publication US 5,465,810 A discloses a device for lubricating an operating component of a system in which the operating component is exposed to a series of conditions, such as a temperature range, that require adjustment of at least one physical property of the lubricant. The device uses a first and a second lubricant that are at least partially miscible under a condition of at least partial miscibility, typically at elevated temperature. Under this condition, the lubricants combine to form a third lubricant. This third lubricant is delivered to the operating component when at least one operating condition changes, requiring the properties of the third lubricant for efficient lubrication.

[0015] Therefore, it is necessary to operate conveying systems for a lubricant in such a way as to increase the service life of the lubricated components.

[0016] This necessity is taken into account by the subject matter of the independent patent claims.

[0017] Some embodiments include a device for operating a conveying system for pumping a lubricant, which includes a sensor interface for receiving an information signal containing information about the ambient temperature in the environment of the conveying system. Knowing the information about the state of the lubricant, the device can output a control signal for the conveying system via a control interface. This control signal causes a change in the conveying characteristic of the conveying system, which includes a piston pump used for pumping the lubricant, depending on the information signal. The control signal reduces the number of pump strokes of the piston pump (8) by adjusting the suction time through a defined pause in a suction position of the piston pump when the ambient temperature information indicates a decrease in the ambient temperature.

[0018] This means the device can react to changing operating conditions and make corresponding technical adjustments and changes to relevant operating parameters of a conveying system for pumping a lubricant. This prevents both oversizing the conveying system and the resulting negative consequences, and reliably avoids under-lubrication of the components to be lubricated, provided information about the lubricant's condition is taken into account when adjusting the conveying system's characteristics.

[0019] According to some embodiments, the delivery rate of the pumping system can be kept largely constant without complex flow measurement devices and complicated control algorithms. According to some embodiments, the pump can adjust the priming time depending on the operating point, for example, the ambient temperature or the drive load, by pausing in the suction position in a defined manner, in order to extend this time, for example, until the entire pumping chamber volume is filled with lubricant. This allows the medium or lubricant the time it needs to flow into the pumping chamber. This can lead to discontinuous delivery, which, due to the pump motor stopping during the priming phase, can counteract a rapid pressure increase, such as could occur with an increase in lubricant viscosity, especially at low temperatures.This in turn can contribute to a more even pressure level in the main line of a conveying system.

[0020] In alternative embodiments, information about the lubricant's condition can be obtained without an additional temperature sensor. For example, the information signal can include data on the power consumption of the pump used to deliver the lubricant, which increases when the pumped medium, i.e., the lubricant, offers greater resistance to the pump. Similarly, the information signal can also include data on the pump's rotational speed, the force generated by the pump, or the torque generated by the pump.

[0021] Alternatively, according to some embodiments, the information signal can contain information about a pressure in the lubricant or about a viscosity of the lubricant in order to directly provide information about the consistency of the lubricant, which can lead to an increase in the accuracy of the control.

[0022] Generally speaking, an information signal containing information about the state of the lubricant can be any signal that describes a quantity or property that can be causally linked to the state of the lubricant.

[0023] According to some embodiments, the control signal causes a change in the pump's operating cycle. In some embodiments, this can result in a reduction of the number of pump strokes per unit of time to allow sufficient time for the lubricant to flow into the pump's delivery chamber. In alternative embodiments, however, the pump's operating cycle can also be increased, meaning the number of pump strokes per unit of time is increased to maintain or increase the net delivery rate.

[0024] According to some embodiments, the control signal can also cause the addition of a substance that reduces the viscosity of the lubricant, in order to help maintain or regain the required delivery rate in the event of a significant increase in viscosity and thus a reduction in volume flow.

[0025] Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying figures. These show: Fig. 1. A schematic representation of a conveying system for conveying a lubricant, with an embodiment of a device for operating the conveying system; and Fig. 2a block diagram of an embodiment of a method for operating a conveying system for conveying a lubricant.

[0026] Fig. Figure 1 shows a schematic view of an example of a conveying system 2 for conveying a lubricant, as well as a device 4 for operating the conveying system 2. The in Fig. The exemplary conveying system 2 comprises a reservoir 6 for the lubricant, a piston pump 8 which forces the lubricant from the reservoir 6 into a main line 12, through which a plurality of lubricant distributors 14a-c are supplied with lubricant. To ensure a quasi-continuous supply, the lubricant flows from the reservoir 6 into a conveying chamber 10, which is formed above the piston of the piston pump 8, from where the lubricant is forced into the main line 12 during a conveying stroke of the piston pump 8. For the sake of simplicity, the valves that may be necessary for the complete implementation of the process are shown in Fig. 1 not shown.

[0027] The device 4 for operating the conveying system 2 has a sensor interface 16 through which it can receive an information signal containing information about the condition of the lubricant. In this case, a temperature sensor 18 is connected to the sensor interface 16, so that the information includes information about the ambient temperature. The device 4 also has a control interface 20 for outputting a control signal that causes a change in a conveying characteristic of the conveying system 2, dependent on the information signal. For this purpose, the control interface 20 is connected to the piston pump 8, for example, to change an operating cycle of the pump in this exemplary embodiment.For example, the device 4 can extend the duration that the piston of the piston pump 8 remains in the position that allows lubricant to flow from the reservoir 6 into the delivery chamber 10 when the temperature falls below a predetermined value. This makes it possible, for example, to ensure that the maximum pumpable volume can be delivered with each piston stroke, even under such circumstances.

[0028] Although in Fig. Figure 1 shows a piston pump 8 for conveying the lubricant; it is self-evident that in alternative embodiments any other conveying devices or pumps can be used for conveying the lubricant. Furthermore, any other information about the condition of the lubricant can of course be used to effect the situation-dependent control of the conveying system 2.

[0029] Information generated or obtained in this way can be analyzed, processed, and evaluated using both an integrated and an external control unit. In other words, the device 4, although it is in Fig. The device 4, shown separately from the piston pump 8, can also be an integral part of the control system for the piston pump 8 or another component used in the conveying system 2. The results of this evaluation by the device 4 can then be used as a basis for corrective measures or changes to the conveying characteristics of the conveying system 2, which can be initiated automatically or after manual confirmation. In summary, a conveying system 2 is thus enabled to react automatically to changing operating conditions and to make corresponding technical adjustments and changes to relevant parameters. These can generally be changes to physical and / or chemical properties of the medium being conveyed, i.e., the lubricant. Furthermore, changes to the environmental conditions can be made.Alternatively or additionally, changes can be made to the effectively usable conveying chamber size, the rotation and / or stroke rate.

[0030] Fig. Figure 2 schematically shows a flowchart of an embodiment of a method for operating a conveying system for transporting a lubricant. In a receiving step 22, an information signal containing information about the condition of the lubricant is received. In a control step 24, a control signal is output for the conveying unit, which causes a change in a conveying characteristic of the conveying system that depends on the information signal.

[0031] Exemplary embodiments of the invention can be advantageously used in any environment, such as in industrial halls where a number of stationary machines need to be lubricated. The application is also particularly advantageous in mobile applications such as construction vehicles, cranes, trucks, or the like, since these are frequently exposed to particularly strong changes in environmental conditions. Reference symbol list 2 Conveyor system 4 Device 6 Reservoir 8 piston pump 10 Funding Chamber 12 Main line 14a - c Lubricant distributor 16 Sensor interface 18 Temperature sensor 20 Control interface 22 Reception step 24 control step

Claims

[1] Device (4) for operating a conveying system (2) for conveying a lubricant, comprising: a sensor interface (16) for receiving an information signal containing information about an ambient temperature in an environment of the conveying system (2); and a control interface (20) for outputting a control signal for the conveying system (2), which causes a change in a conveying characteristic of the (8) conveying system (2) which includes a piston pump used for conveying the lubricant, depending on the information signal, wherein the control signal causes a reduction in the number of pump strokes of the piston pump (8) by adjusting the suction time by a defined stop in a suction position of the piston pump when the information about the ambient temperature indicates a reduction in the ambient temperature. [2] Device (4) according to claim 1, wherein the information signal further includes information about the current consumption of the piston pump (8), the rotational speed of the piston pump (8), the force generated by the piston pump (8) or the torque generated by the piston pump (8). [3] Device (4) according to one of the preceding claims, wherein the information signal further contains information about a pressure in the lubricant or a viscosity of the lubricant. [4] Device (4) according to one of the preceding claims, wherein the control signal causes a change in an operating cycle of the piston pump (8) or in a force generated by the piston pump (8). [5] Device (4) according to one of the preceding claims, wherein the control signal causes the addition of an additive that reduces the viscosity of the lubricant. [6] Conveying system (2) for conveying a lubricant, comprising: A device (4) according to any one of claims 1 to 5; and At least the piston pump (8) used to pump the lubricant.

Images