LUBRICANT DISPENSER

Description

[0001] The invention relates to a lubricant dispenser with at least a lubricant supply, e.g. a cartridge filled with lubricant, an electromechanical drive, e.g. an electric motor which operates on at least one actuating element (e.g. a piston, a pump or the like) to eject lubricant from the lubricant supply, a battery (or battery arrangement with several batteries) which provides a battery voltage, a control board arrangement which has at least one main board with an electronic circuit arrangement with at least one central microcontroller and additional functional components and conductor tracks, wherein the control board arrangement is connected on the one hand to the battery and on the other hand to the electromechanical drive.

[0002] Such lubricant dispensers are used, for example, for the automated lubrication of machine or system components such as rolling bearings, plain bearings, linear guides, chains, or the like. The lubricant dispensers are connected to a lubrication point (e.g. a bearing) and can dispense lubricants, for example, depending on the running time of a machine or at predetermined or variable intervals. Greases or oils, for example, are used as lubricants. The reservoir is also referred to as a cartridge, and such a cartridge can usually be detachably and replaceably connected to an electromechanical drive or a housing of the lubricant dispenser to form a structural unit, e.g. by means of a screw connection, plug connection, snap connection, bayonet connection, or the like. The electromechanical drive is preferably an electric motor orThe electromechanical drive or drive unit comprises an electric motor. The electric motor is preferably a (battery-operated) DC motor. The electromechanical drive and the control board assembly are typically located in a (common) housing of the lubricant dispenser, which is coupled, for example, to the lubricant reservoir.

[0003] The electromechanical drive can, for example, operate on an actuating element designed as a piston, which is guided, for example, in the lubricant cartridge for pressing out the lubricant, wherein the piston is connected, for example, to a spindle or the like, which is driven by the electromechanical drive. The circuit board arrangement, which is arranged, for example, inside the housing of the lubricant dispenser, accommodates a circuit arrangement as the control electronics of the lubricant dispenser. The electromechanical drive is specifically controlled via this control electronics, for example to dispense lubricant at preselected dispensing intervals. The control electronics can also determine the temperature, for example to dispense the lubricant depending on the temperature or to control the drive depending on the temperature. Furthermore, displays can be implemented via the control electronics, e.g.LCD displays and / or LED displays as well as a control panel for adjusting the lubricant dispenser.

[0004] A lubricant dispenser of the type described above with an electromechanical drive is marketed by the applicant, for example, under the product name "Star Vario." Simple and self-explanatory operation is achieved via an LCD display with adjustment buttons, allowing adjustments to be made at any time. The electromechanical, reusable drive with battery pack ensures reliable, precise lubricant dispensing, regardless of temperature and backpressure.

[0005] DE 10 2011 056 247 B4 and DE 4422407 A1 describe a generic lubricant dispenser with an electromechanical drive that actuates a piston via a spindle, with a control board also being integrated into the housing of the lubricant dispenser.

[0006] Furthermore, from DE 10 2012 100 035 B4 a lubricant dispenser of the type described above is known, in which the lubricant cartridge is detachably connected to a carrier or housing which accommodates a battery-operated motor for driving the spindle, wherein in this embodiment too the spindle is connected to a piston for squeezing the lubricant out of the reservoir.

[0007] As an alternative to these embodiments, in which the drive operates via a spindle on a piston as the actuating element, the invention also encompasses embodiments in which an electromechanical drive drives a pump to convey a lubricant from a reservoir to an outlet. Such an embodiment is known, for example, from DE 10 2019 106 681 A1.

[0008] The invention therefore always relates to a lubricant dispenser with an electromechanical drive, e.g., with an electric motor. The electric motors are generally designed as DC motors powered by one or more batteries. Such lubricant dispensers with electromechanical drives have proven extremely effective in practice, as they enable, in particular, reliable, precise, and variably adjustable lubricant dispensing. They can be used in a wide variety of environments.

[0009] However, particular challenges arise when the lubricator is to be used in potentially explosive areas where safety is of particular importance, such as areas where flammable substances are manufactured, processed, transported, or stored. Potentially explosive areas can occur, for example, in the chemical and petrochemical industries, as well as in oil and gas production and mining. Potentially explosive areas are also known in the automotive industry, for example, in paint shops. Furthermore, this includes power plants and steel mills, and areas where coal or similar materials are transported, where conductive, explosive dust occurs.

[0010] To ensure a high level of safety in such areas, there are usually strict legal safety requirements and standards that plant operators must adhere to. Potentially explosive areas are divided into different zones, each requiring a different level of safety. Zone 0 represents the greatest danger and therefore the highest level of safety.

[0011] Particularly in such zones with the highest safety levels, electrochemical lubricant dispensers are used in practice for the automated lubrication of machines, systems, or the like. These do not operate with an electric motor drive, but rather with electrochemical drives equipped with electrochemical gas cells, which, for example, actuate a piston to expel the lubricant. The use of electrochemical lubrication systems has proven successful in potentially explosive areas. However, there is a fundamental need to also use electromechanical lubrication systems in potentially explosive areas. This is where the invention comes in.

[0012] The invention is based on the object of creating an electromechanically operated lubricant dispenser of the type described above, which is characterized by a high degree of intrinsic safety. Preferably, the lubricant dispenser should also be usable in potentially explosive atmospheres of "Zone 0," i.e., have an EPL (Equipment Protection Level) "a."

[0013] To achieve this object, the invention teaches, in a generic lubricant dispenser of the type described above, that the electronic circuit arrangement is divided into several circuit islands (so-called "explosion-proof islands") or has several circuit islands, with some or all of the circuit islands each being power-limited. Accordingly, the invention provides that the maximum possible power within each circuit island is limited to a predetermined maximum value.

[0014] The invention is based on the recognition that in the electronic components of the lubricant dispenser and in particular on or in the control board arrangement, on the one hand, excessive temperature increases must be limited or avoided and, on the other hand, sparking must be avoided or the spark energy generated during sparking must be severely limited.

[0015] Dividing the electronic circuitry into multiple explosion-proof islands has the advantage that the maximum possible power can be limited in each individual protection island, e.g., by a power-limiting series resistor. If, for example, a short circuit were to occur in a circuit island connected by a power-limiting resistor, the maximum possible power would be dissipated in this island or the affected faulty part. By using a power-limiting resistor, this maximum possible power is reduced; the resistor goes into power adjustment, so that the available electrical power is only the reduced value calculated from P = U 2 < / (4 x R).In practice, the power-limiting resistor is then designed so that, in the event of a fault during power adjustment, the maximum possible power does not exceed the maximum permissible power dissipation for the integrated circuits used in the circuit island. To achieve a particularly high level of explosion protection, a safety factor can also be considered.

[0016] The measures according to the invention make it possible, in particular, to select relatively small spacings between conductor tracks and component sizes within each individual protective island. In contrast, the spacings between conductor tracks and components between individual protective islands are selected to be larger, so that overall, undue heating and sparking are reliably avoided. Thus, it is preferably provided that the spacings of the conductor tracks between individual circuit islands do not fall below a predetermined minimum distance, whereby this minimum distance is preferably greater than the spacing of the conductor tracks within the circuit islands. This allows even very small SMD components with close spacing and, in particular, close spacing of the connections to be used within the circuit islands. In this way, the respective specifications from the relevant standards, e.g., from the IEC 60079-11 standard, can be implemented according to the invention.

[0017] The division of the circuit arrangement into several explosion-proof islands is an essential aspect of the invention, which will be discussed in more detail below. Even if, according to the invention, the explosion-proof islands are each power-limited, circuit islands can be implemented within the control board arrangements whose components do not permit power limitation, e.g., in the case of a motor in which the use of a power-limiting series resistor would generate such a large voltage drop that the remaining residual voltage would no longer be sufficient for the correct operation of the motor. In such circuit islands, in which power limitation via, for example, a resistor is dispensed with, it is expedient to implement a temperature fuse in each case. This will also be discussed below.

[0018] The focus is on limiting the power of the individual circuit islands, or at least some of them. For this purpose, the aforementioned power-limiting resistors, e.g., series resistors, are preferably used. Alternatively or additionally, (additional) power limitation can be implemented between individual circuit islands, preferably by one or more resistors (intermediate resistors) arranged between the interconnected circuit islands or integrated into the electrical connection between the respective circuit islands. For example, a (central) circuit island is implemented with a central microcontroller, and one, several, or all other circuit islands are connected to this central circuit island.Since the individual circuit islands are each supplied with power separately, it is advantageous if the central circuit island with the microcontroller is protected by the aforementioned intermediate resistors, across which, for example, the short-circuit voltage drops in the event of a short circuit on a circuit island, thus protecting the central circuit island. In addition to the above-mentioned series resistors, which are integrated into the power supply line in the aforementioned circuit islands, intermediate resistors can be integrated between individual circuit islands that are electrically or functionally connected to each other to protect a circuit island if a fault occurs in a neighboring circuit island.

[0019] In a preferred development of the invention, the operational reliability or intrinsic safety of the lubricant dispenser can be improved by providing or connecting the circuit arrangement (as a whole) with a current limiting device which limits the total energy within the (entire) circuit arrangement. In addition to the power limitation within the individual protective islands, an overall current limitation is therefore preferably implemented so that, in particular, the energy of a spark that could potentially occur in the event of a defect is limited. The aim here too is to achieve the desired explosion protection level, e.g. for use in Zone 0. The current limiting device is preferably designed with multiple redundancy. For this purpose, several, e.g. at least three current limiters, which are connected in parallel, for example, are optionally implemented. The redundancy ensures the operational reliability orIntrinsic safety is further increased because even in the event of a failure or defect of one or possibly two current limiters, the overall current limiting device of the circuit arrangement functions reliably, thus reliably reducing the energy limitation within a resulting spark. Optionally and particularly preferably, the current limiting device (additionally) includes a fuse, e.g., a safety fuse. When the maximum permissible current is reached, the safety fuse is destroyed in a controlled manner, e.g., via a crowbar circuit.

[0020] In an alternative embodiment, an active (multi-redundant) current limiting device with active current limiters may be omitted. It may be sufficient to use only one fuse, e.g., a fuse, or optionally, multiple fuses, e.g., fuses, for current limitation.

[0021] According to a further aspect of the invention, the circuit arrangement is preferably provided with or connected to a voltage regulator which reduces the battery voltage to a regulated operating voltage. Such a configuration is particularly advantageous when components are used which must / should be operated at a lower voltage than that supplied by the battery(ies). Furthermore, standards may require a safety margin between the maximum permissible voltage and the voltage used. In order to reduce this permissible (voltage) safety margin, a regulated voltage reduction is implemented, with the voltage supply for these components also preferably being designed with triple redundancy. Thus, it is provided that the voltage regulator is designed with multiple redundancy and preferably comprises several, e.g. at least three, voltage regulators, which are preferably connected in series.Since, in the event of a voltage regulator failure, the components would no longer be supplied with the reduced voltage (e.g. 3.3 V) but with the full battery voltage (e.g. 4.5 V), the multiple redundant design has the advantage that components, e.g. a microcontroller, can actually be used that are designed for the reduced voltage and do not have to be designed for the higher battery voltage. So-called LDO components, i.e. low-dropout voltage regulators, are particularly preferred as voltage regulators. The alternative Zener diodes, which are usually used to limit the voltage in explosion protection, are preferably dispensed with.

[0022] The use of a voltage device or voltage regulator has the advantage that components designed only for this reduced voltage, such as a microcontroller, can be used without compromising safety. However, the redundancy is particularly advantageous when such components are used.

[0023] It is also possible to design the voltage regulation device or each individual voltage regulator as a separate circuit island with power limitation, so that, for example, the voltage regulation device as a whole or, preferably, each individual voltage regulator can be limited by a power-limiting resistor. In the case of voltage regulators, such a power-limiting resistor is preferably not connected as a series resistor, since a voltage drop across the series resistor could lead to too low a voltage for the downstream components. For this reason, it is advisable to provide a power-limiting resistor in the ground line of the component, e.g., in the ground line of the voltage regulator (e.g., LDO), so that the full voltage is available for the voltage to be regulated and only the control circuit itself is current-limited.

[0024] According to a further interesting aspect of the invention, it is optionally provided that the control board arrangement is not only implemented by a single board, but that in addition to the main board, an additional board connected to it is provided. For example, it is possible to arrange the current limiting device on the additional board. Alternatively or additionally, the voltage regulation device can be arranged partially or completely on the additional board, for example by arranging one or more voltage regulators on the additional board and, if appropriate, at least one voltage regulator on the main board. It can be advantageous to implement all voltage regulators on the additional board.

[0025] A first advantage of the design with a main board on the one hand and an additional board on the other hand is that different types and sizes of insulating protective coatings can be implemented for the circuits. In order to increase operational reliability or intrinsic safety, it can be advantageous to provide the circuit arrangement partially or completely with one or more electrically insulating protective coatings. This can be implemented differently on the main board on the one hand and the additional board on the other. It can therefore be expedient to dispense with a protective coating entirely on the main board and only provide a protective coating (partially or completely) on the additional board. Alternatively, it is within the scope of the invention if the components on the main board are coated at least partially with a protective coating, e.g. a protective varnish. This makes it possible, for example, tothe possibility of reducing the distances between the conductor tracks between individual protective islands, namely in the areas where the conductor tracks and components are coated with a (standard-compliant) protective coating. Technically, there may be areas in which the function of components would be negatively affected by a protective coating, e.g. in the area of ​​optical or mechanical components, e.g. LED lenses or buttons. There may therefore be areas in which a protective coating is completely omitted. In these areas, relatively large distances between the components / conductor tracks are then realized. In other areas of the mainboard, components may be hidden by other components, making protective coating impossible or difficult. Even in these areas, e.g. under a display, components and conductor tracks can be designed in such a way that they comply with the standard-specified distances without protective coating.Overall, the mainboard can be specifically designed to coat as many areas as possible with a protective coating, allowing the gaps in these areas to be further reduced. Regardless of this, it is important to note that a distinction can be made between the gaps between individual protective islands on the one hand and within the protective islands on the other. As described, it is also possible to completely dispense with a protective coating, such as a protective coating, on the mainboard.

[0026] A particular advantage of implementing a (separate) add-on board is that the add-on board can be provided with a protective coating - independently of the main board - e.g., it can be provided with a protective coating or encased in sections or completely. This means that the add-on board can be completely encapsulated or injected into an electrically insulating material. It can also be expedient or sufficient to provide the add-on board with a coating only on one side of the board (completely or partially), e.g., with a suitable potting compound, so that the board is only potted on one side. In addition to electrical insulation, potting has the advantage that heat can be dissipated over a large area through the potting compound.Any heating of components that would cause the surface temperature to exceed the permissible explosion protection limit is absorbed by the encapsulation and slowly transferred to the encapsulated surface, ensuring that the encapsulated surface temperature remains within the permissible limits. Furthermore, the encapsulation—like a protective coating—enables the realization of smaller conductor track and component spacing and sizes.

[0027] In one possible, particularly advantageous embodiment, all voltage regulators (e.g., three voltage regulators) are arranged on the additional circuit board. All voltage regulators can be implemented very close to one another on the additional circuit board, so that all voltage regulators can be equipped with one or more thermal fuses, e.g., a common thermal fuse, for example, by gluing a thermal fuse over all three voltage regulators. In the event of a fault or excessive heating, the thermal fuse triggers, thus de-energizing the device. As already mentioned, the additional circuit board can be partially or completely encapsulated, or, for example, encapsulated on the top side where all components are mounted.In principle, it may be sufficient to distribute the heat generated by the voltage regulators across the circuit board's encapsulation so that the encapsulated surface does not exceed the temperature permitted for the protection level. However, the optional thermal fuse can prevent the encapsulation compound itself from overheating, thus preventing, in particular, the maximum permissible temperature of the encapsulation compound from being exceeded, for example, directly at a voltage regulator, and thus damaging the encapsulation compound. Such damage to the encapsulation compound must be avoided to ensure the important property of hermetically sealing an ignitable gas mixture for explosion protection.

[0028] Overall, it is possible to vary the spacing of the conductor tracks and components. Preferably, a predetermined first minimum spacing, which may be, for example, 1.5 mm, is implemented between individual circuit islands without a protective coating. Alternatively or additionally, a second minimum spacing, which may be, for example, 0.5 mm, can be implemented between individual circuit islands with a protective coating. Alternatively or additionally, a third minimum spacing, which may be, for example, 0.2 mm, can be implemented within a circuit island. In this case, it is irrelevant whether a protective coating is implemented, since the power is limited in the area of ​​the circuit island anyway.

[0029] The design with a main board on the one hand and an additional board on the other hand has the further advantage that all components required for the function of a lubricant dispenser, regardless of use in potentially explosive areas, are implemented on the main board, and that the additional components required for the operation of the lubricant dispenser in potentially explosive areas are provided on the additional board. Consequently, in a preferred embodiment, the main board can be fully or essentially functional without the additional board, but then for use in non-potentially explosive areas. The additional board can, for example, be arranged "piggyback" on the main board, e.g., plugged onto the main board and / or soldered. Since current limitation and voltage regulation are of particular importance (e.g.,For explosion-proof applications, the current limiting device and the voltage control device are preferably arranged entirely or partially on the additional circuit board. The current limiting device is particularly relevant for the explosion-proof version of the circuit arrangement, so it can be arranged entirely on the additional circuit board. Voltage control can also be advantageous if the lubricant dispenser is not intended to be operated in explosion-proof areas. However, multiple redundancy of the voltage control device is then not necessary. For this reason, at least one voltage regulator can optionally be arranged on the main circuit board, while the other voltage regulators for redundancy can be arranged on the additional circuit board.However, it is preferable to locate all voltage regulators (required for the explosion-proof version) on the add-on board, so that in this case, no voltage regulator is provided on the main board. However, if this board is optionally intended for operation in a non-explosion-proof area, the add-on board is omitted and the main board can be optionally equipped with a voltage regulator instead.

[0030] In a further possible embodiment, it may be advantageous to equip the control board arrangement with a board detection system that automatically detects whether an additional board is provided, e.g. plugged or soldered onto the main board or connected to the main board. This can be achieved, for example, by operating a pin of the microcontroller with a pull-up resistor. By connecting or soldering the additional board, this pin is connected to ground and the (soldered) additional board is thus detected. This detection system is preferably integrated into the programming of the microcontroller, e.g. in the software, i.e. the software detects whether the additional board is soldered on. This has the advantage that the software parameters can be adjusted accordingly as a result of the detection. This means, for example, that any special functions in the explosion-proof version can be automatically activated or deactivated.Adapt the operating mode to whether the additional board is implemented or not, or whether the board arrangement is intended for the explosion-protected area. For example, a functionality is provided that ensures compliance with certain parameters for the explosion-protected version. For example, the maximum runtime could be limited if the battery pack capacity cannot cover the additional power requirements for the additional explosion-protected electronics. Thanks to automatic detection, no separate software is required for this case, as the parameters are adjusted automatically.

[0031] As already explained, the circuit arrangement contains several circuit islands, each of which preferably has its power limited. Such a circuit island can, for example, accommodate the microcontroller as the central component, whose power is limited, for example, by a series resistor. Additional components can be integrated into this circuit island as functional components. However, these components are only supplied with power via the microcontroller and are not themselves connected to the battery or the voltage regulator, so that these additional components do not need to be power limited themselves. For more information, refer to the description of the figures.

[0032] Additional circuit islands can each contain functional components that are connected to the reduced and regulated battery voltage, i.e., to the voltage regulator, and are also connected to the microcontroller. For these components, it is advantageous if, for example, a power-limiting resistor or series resistor is provided between the circuit island and the microcontroller.

[0033] Further details and optional designs of the circuit islands and their assembly are explained as examples in the figure description.

[0034] The key component of the lubricant dispenser is the electromechanical drive, as the invention provides an electromechanical lubricant dispenser for use in potentially explosive environments. The electromechanical drive is preferably designed as a DC motor or equipped with such a DC motor. A brushless DC motor (BLDC motor) is particularly preferred as the drive. This motor variant dispenses with the brushes found in other motor types, thus preventing the occurrence of brush sparks. This is particularly advantageous due to its use in potentially explosive environments, as in these environments the energy of even small sparks can be sufficient to trigger an explosion. BLDC motors also have the advantage of having a much lower inductance than that of a conventional brushed motor.The use of a BLDC motor allows for higher voltages and higher currents to flow throughout the electronics than with a brushed motor. This means a motor with high torque and low power consumption is used.

[0035] The lubricant dispenser can optionally be designed for wireless communication. For this purpose, the circuit arrangement can be equipped with a communication module, e.g. a radio module, which is arranged, for example, on the main board (e.g. as a separate circuit island). The option of wireless communication, e.g. via radio, is particularly advantageous in potentially explosive areas, since the lubrication points where the lubricant dispensers are used are often difficult to reach and there are often special requirements regarding occupational safety. A Bluetooth protocol, for example, can be considered as a radio protocol, i.e. the radio module can be designed as a Bluetooth module, e.g. as a Bluetooth Low Energy module (BLE). Alternatively, other radio modules or other transmission protocols can also be considered, e.g. WLAN, LPWAN (e.g. LoRa, SigFox).Wireless communication makes it possible to maintain the lubricators, retrieve information, and, if necessary, make adjustments. Lubricators can be equipped with a display and adjustment options on the lubricator. However, it can also be advantageous to transmit the information to a suitable device, e.g. a smartphone, tablet, or computer, so that information can be read from there and, if necessary, settings on the lubricator can be changed. This eliminates the need for wired connections, which are particularly problematic in potentially explosive areas. The battery-operated lubricator with wireless communication has the advantage that there is no need to intervene in the system's power supply. The user can wirelessly access various information from the lubrication system from a safe distance, e.g.with an explosion-proof smartphone. Conversely, personnel can also wirelessly send information to the lubrication system, e.g., to acknowledge faults or trigger special dispensing. Gateways can optionally be used to enable personnel to be away from the lubrication point, meaning communication is possible even beyond Bluetooth range. Information can also be requested directly from the system's control room.

[0036] In a preferred embodiment, the circuit arrangement, e.g. the main board, is equipped with a communication module which is connected on the one hand to the microcontroller and on the other hand to the regulated battery voltage or the operating voltage. Such a communication module, e.g. Bluetooth module, can also be implemented as a separate circuit island. In this case, power limitation via a series resistor may not be possible, since the module requires a relatively high current for a corresponding transmission power, i.e. the module cannot be power limited. In this case, it may be expedient to equip such a circuit island with an additional, separate fuse, e.g. a temperature fuse, which triggers at a certain trigger temperature. Consequently, protection islands can also be implemented which are not power-limited via a series resistor, but which are each equipped with their own safety mechanisms, e.g.are equipped with temperature fuses.

[0037] The same applies, for example, to a protective island that houses the motor circuit. In the case of the motor, power limitation via a series resistor may not be possible. However, it must be ensured that the energy stored in the motor coils is limited. This is achieved through the current limitation described above. Power limitation via a series resistor is not possible with a motor, e.g., a BLDC motor, because the high current of the motor across a series resistor would cause such a large voltage drop that the remaining voltage would no longer be sufficient for the motor to operate correctly. It may also be expedient to use a BLDC motor without Hall sensors to determine the position of the rotor, since Hall sensors may not be able to operate in a low voltage range. The use of motors with Hall sensors is only possible at higher voltages.When controlling a BLDC motor without Hall sensors, certain conditions or specifications must be taken into account. The control could either be carried out directly via the microcontroller (with a downstream driver stage), i.e. the control is then regulated via software. Alternatively, a suitable BLDC motor controller is used. This motor controller receives a PWM signal from the microcontroller to specify the speed. The control of the motor, including the driver stage, is preferably fully integrated into the motor controller. The motor controller sends a speed signal to the microcontroller so that the microcontroller can monitor the number of motor revolutions. The motor controller itself can, in turn, be power-limited via a series resistor.Alternatively, it is also possible to protect the motor controller against excessive heating using a thermal fuse, so that in this case a power-limiting resistor is not necessary.

[0038] Overall, the measures according to the invention provide a lubricant dispenser that is equipped with an electromechanical drive and is also suitable for use in potentially explosive environments. The described measures limit the voltages and currents flowing on a circuit board. Temperature increases are limited or avoided. Sparks are avoided or the spark energy is limited. Should faults occur, the explosion-relevant circuit areas are equipped with protective mechanisms, preferably multiple, preferably triple, redundant.

[0039] Depending on the design, the measures according to the invention can be used to achieve explosion protection certification for the desired level, e.g. for gas group IIB or IIC.

[0040] Furthermore, the invention also relates to a control board assembly of the type described, which is configured for the described lubricant dispenser in the manner described. The control board assembly, which preferably consists of a main board and an additional board and in which it is particularly important that several separate circuit islands are designed as explosion-proof islands, is therefore also protected independently.

[0041] The invention is explained in more detail below with reference to drawings, which represent only one exemplary embodiment. They show: Fig. 1 shows a lubricant dispenser in a simplified representation, Fig. 2 shows a block diagram of a circuit arrangement of the lubricant dispenser according to Fig. 1 , Fig. 3 a block diagram of an additional board of the circuit arrangement according to Fig. 2 , Fig. 4the voltage regulators of the additional board according to Fig. 3 , Fig. 5 an alternative design of the additional board according to Fig. 3 with simplified current limitation, Fig. 6 an alternative embodiment of a circuit arrangement according to Fig. 2 Fig. 7 an alternative embodiment of the voltage regulator on the additional board.

[0042] The figures show a lubricant dispenser 1 intended for use in potentially explosive atmospheres. The lubricant dispenser 1 is used for the automated lubrication of, for example, machine and system components and is preferably used for single-point lubrication. In principle, however, it can also be used for multi-point lubrication. The basic structure of the lubricant dispenser 1 shown as an example in the figures includes a lubricant reservoir 2 in the form of a lubricant cartridge 2, which is filled with lubricant and has an outlet opening 3 for the lubricant. An actuating element 4 in the form of a piston 4 is arranged in the cartridge 2 for pressing the lubricant out of the outlet opening 3. This piston 4 is arranged on a rotatable spindle 5.The lubricant cartridge 2 is connected to a drive 7 arranged in a housing 6. This drive 7 is designed as an electromechanical drive. In the exemplary embodiment, this is an electric motor drive or an electric motor 7, in particular a DC motor, which is preferably designed as a brushless DC motor. The motor 7 drives the spindle 5, via which the lubricant is pressed out of the cartridge 2.

[0043] To supply energy to the lubricant dispenser 1, a battery 8 or a battery arrangement with several batteries 8 is provided, which provides a direct voltage as battery voltage VB (e.g. 4.5 V). Furthermore, a control board arrangement 9 is provided, which is also arranged in the housing 6. This control board arrangement 9 has an electronic circuit arrangement with at least one central microcontroller 10 and additional electronic functional components as well as conductor tracks 11. The control board arrangement 9 is connected on the one hand to the battery 8 and on the other hand to the drive 7. The control board arrangement 9 is designed to control the drive 7 and thus to control the lubricant dispenser 1. For this purpose, the lubricant dispenser 1 is equipped with various electronic components that are arranged on the control board arrangement or connected to it.In particular, a display device 12 and / or setting options 13, e.g., setting buttons or the like, can be provided to make and / or read changes to the configuration of the lubricant dispenser 1, e.g., dispensing intervals or the like. Furthermore, the control board arrangement can be equipped with or connected to sensors, e.g., a temperature sensor.

[0044] According to the invention, the control board assembly 9 is designed for the operation of the lubricant dispenser in potentially explosive environments, preferably for "Zone 0" environments. For this purpose, the voltages and currents flowing on the board assembly are limited. Temperature increases must be limited or avoided, and sparks must be avoided or the spark energy limited.

[0045] To this end, the invention provides that the electronic circuit arrangement is divided into several circuit islands E1 to E9, also referred to as explosion-proof islands. At least some of these circuit islands are each (separately) power-limited, e.g., by power-limiting resistors, e.g., series resistors R1, R1', R2, R3.

[0046] In Fig. 2 The circuit arrangement is shown in Figure 6 and it can be seen that a plurality of protection islands are formed, which are designated, for example, with E1 to E7 and E10.

[0047] An explosion-proof island E1 includes the microcontroller 10 and additional functional components such as a visual display, e.g., an LCD display 14, a temperature sensor 15, and / or a filter unit 16 for filtering or smoothing the motor current. Further, separate circuit islands E2-E6 include, for example, an illumination 17 for the (LCD) display, a radio module, e.g., a Bluetooth module 18, an LED array 20, a circuit component 19 for measuring the battery voltage, and a motor controller or the motor connection device 21.

[0048] It is particularly important that the circuit islands that are connected to the battery or supplied with battery voltage are designed in such a way that the maximum possible power within each circuit island is limited, for example, by a power-limiting resistor, such as a series resistor. Circuit islands without power limitation can be equipped with a thermal fuse. This will be discussed further below.

[0049] Of particular importance is also that the circuit arrangement according to the invention is provided with a current limiting device 22, which limits the total energy within the circuit arrangement. Furthermore, the circuit arrangement is provided with a voltage regulator 23, which reduces the battery voltage VB to a regulated operating voltage VR.

[0050] In the illustrated embodiments, the circuit arrangement comprises, on the one hand, a main board 9a and, on the other hand, an additional board 9b arranged on the main board 9a, which in Fig. 2 or 6 top right and in Fig. 3 or 5. The additional board 9b accommodates in particular the current limiting device 22, which is optionally according to Fig. 3 can be designed with multiple redundancy and comprises three current limiters 22a, b, c that are connected in parallel. The voltage control device 23 is also designed with multiple redundancy. For this purpose, it has three voltage regulators 23a, b, c that are connected in series. A comparative analysis of the Figuren 2 and 4 that of these three voltage regulators (in the embodiment according to Fig. 2 or 4) a voltage regulator 23a is arranged on the main board 9a, while two further voltage regulators 23b, 23c are arranged on the additional board 9b. The voltage regulator 22a on the main board 9a and the voltage regulators 23b, 23c on the additional board 9b each form a separate explosion-proof island E7, E8, E9.

[0051] In Fig. 3 or 5 it can be seen that the battery voltage VB of, for example, 4.5 V is connected to the current limiting device 22 and voltage regulating device 23. This battery voltage is reduced to the regulated operating voltage VR' or VR of, for example, 3.3 V via the voltage regulating device 23. The circuit arrangement therefore contains three voltage specifications: firstly, the output voltage VB of the battery of 4.5 V, which is arranged behind the current limiting devices and an additional fuse, secondly, the non-reduced main voltage VM of also 4.5 V and finally the reduced, regulated operating voltage VR' or VR of 3.3 V. In addition, the voltage drop V s across the shunt resistor 25 is shown.

[0052] In Fig. 2 It can be seen that the reduced operating voltage VR' supplied by the additional board 9b is still fed through the third voltage regulator 23a, at whose output the reduced operating voltage VR relevant for the electronic circuit is available. This supplies Fig. 2 e.g., the explosion-proof island with the microcontroller and the LCD illumination. It can be seen that these explosion-proof islands, which are connected to the reduced battery voltage, are power-limited via resistors R1, R1', R2, and R3. Thus, the explosion-proof island E1 of the microcontroller 10 is power-limited via at least one power-limiting series resistor, e.g., the series resistor R1. Fig. 2 In the embodiment shown in Figures 1 and 6, the microcontroller is connected to the reduced, regulated operating voltage VR via two power-limiting series resistors R1, R1'. One of the connections supplies the digital parts of the microcontroller 10 and the other supplies the analog parts, e.g., the analog-to-digital converter, with the voltage. Within the explosion-proof island E1 of the microcontroller 10, the functional components also provided there are not directly connected to the operating voltage, but only to the microcontroller 10, so that these functional components do not have to be power-limited separately via series resistors. Furthermore, it can be seen that, for example, the explosion-proof island E5 is power-limited via the series resistor R2. The explosion-proof islands E2, E4, and E10 are also power-limited, each via a series resistor that is not shown in the figures.

[0053] The voltage regulators 23a, b, c themselves are also power-limited via resistors R3, so that the two voltage regulators 23b, c arranged on the additional board 9b and the voltage regulator 23a arranged on the main board 9a each form a separate explosion-proof island E7, E8, E9.

[0054] The resistors R1, R1', R2 and R3 mentioned are series resistors that limit the power of the respective assigned circuit island. Furthermore, the drawings show resistors R4, R5, R6, R7, R8 and R9, which are not power-limiting series resistors, but rather resistors that are arranged between the individual explosion-proof islands and in this way implement power limitation between the interconnected explosion-proof islands. In the illustrated embodiment, this serves in particular to protect the central explosion-proof island E1 and the microcontroller 10, because the other explosion-proof islands are connected to this explosion-proof island E1 via resistors R4, R5, R6, R7, R8 and R9. In a simplified schematic, in some connections only a single intermediate resistor R4, R5 orR6 is shown and in some connections groups of intermediate resistors R7, R8 and R9 are shown as examples, since several connecting lines between the explosion-proof islands are also shown there.

[0055] Furthermore, in Fig. 3 or 5 that the current limiting device 22 additionally comprises a fuse 24.

[0056] In Fig. 5 An alternative embodiment for the current limiter 22 is shown, which can also be used in conjunction with Fig. 2 or Fig. 6 can be used. Fig. 5 , again shows a simplified version of the additional circuit board 9b with the voltage regulator 23 and a current limiting device 22. This current limiting device is not actively configured and therefore does not have any active current limiters. Instead, the current limiting unit 22 consists merely of a fuse 24 that limits the total current.

[0057] While Fig. 4 combined with Fig. 2 shows an embodiment in which only a part of the voltage limiting device 23 is arranged on the additional board, the Figuren 6 and 7 an alternative, advantageous embodiment in which the entire voltage limiting device 23 with all (three) voltage limiters 23a, 23b, 23c is arranged on the additional board. Fig. 6 The version of the main board shown differs from the one in Fig. 2 illustrated embodiment, especially in that no voltage limiter is located on the main board 9a (in explosion-proof operation), since all voltage limiters are located on the additional board. The main board according to Fig. 6 can therefore be used with the additional board according to Fig. 3 equip, whereby the Fig. 3 voltage control device 23, which is only shown in a simplified manner, then according to Fig. 7 equipped with all voltage limiters 23a, 23b, 23c. The additional board can also be used with the main board according to Fig. 6 optionally either with the active current limitation acc. Fig. 3 or with the simplified current limitation via the fuse according to Fig. 4 be realized.

[0058] In this case, Fig. 6 (dashed line) indicates that a voltage regulator 23' can also be arranged on the main board 9a. However, this only applies if the main board 9a is to be used without the additional board 9b for non-Ex protection areas. The main board 9a is therefore only equipped with a voltage regulator 23' or E7' in the non-Ex version. In the Ex-protection version, the voltage regulator 23' is missing from the main board 9a according to. Fig. 6 , since all voltage regulators in this embodiment are arranged on the additional board, as in Fig. 7 shown.

[0059] To automatically activate any special functions in the explosion-proof version of the board, a detection feature can be implemented that automatically detects whether the additional board is soldered on. For this purpose, a pin of microcontroller 10 can be operated with a pull-up resistor. Soldering the additional board connects this pin to ground. Thus, the soldered additional board is automatically detected (via the software stored in the microcontroller).

[0060] In Fig. 5 It is also indicated that the additional board 9b and in particular the voltage limiter 23 can be equipped with a temperature fuse 26.

[0061] Optionally, a radio module, e.g., a Bluetooth module 18, is provided on the main board, which can also be designed as a separate explosion-proof island E3. Fig. 2 or 5 that this explosion-proof island E3 or this radio module 18 is not power-limited by a series resistor. Since the module requires a relatively high current for a corresponding transmission power, power limitation via a series resistor is omitted. However, an additional temperature fuse is arranged in the explosion-proof island, which triggers at a certain trigger temperature, so that power limitation via a series resistor is not necessary for this explosion-proof island. The temperature fuse is glued to the surface of the radio module 18 using a temperature-conductive adhesive, for example. Details are not shown. The Bluetooth module 18 shown in the drawing is merely one possible option for a radio module. Radio modules with other transmission protocols can also be used. The focus is on the possibility of wireless communication.

[0062] The explosion-proof island E6 for the motor connection or motor controller 21 is also not power-limited by a series resistor. Here, too, a thermal fuse is bonded to the surface of the circuit board or circuit board section, e.g., using a thermally conductive adhesive. For example, a BLDC motor without Hall sensors is used to determine the rotor position, since such a motor can operate with low voltages without Hall sensors. Control is via a BLDC motor controller. This motor controller 21 receives a PWM signal from microcontroller 10 to specify the speed. The motor control, including the driver stage, is fully integrated into the motor controller 21. The motor controller 21 itself is protected against excessive heating by a thermal fuse as described.Furthermore, the energy stored in the motor coils is limited to prevent temperature increases and sparking. This is achieved by the current limiter described above, which is integrated into the additional circuit board, so that no power limitation via an additional series resistor is required for this explosion-proof island.

[0063] The current limiter 22 implemented in the embodiment on the additional board 9b limits the current of the entire circuit 9 at a central point.

[0064] This eliminates the need for any current-limiting measures in the remaining or individual circuit components or explosion-proof islands. The power-limiting resistors R1, R1', R2, and R3 of the explosion-proof islands serve, independently of the current limiting, to ensure that in the event of a fault in an integrated component, e.g., a short circuit that could occur within the component, this component is not loaded beyond its maximum power. In principle, a fault could also occur in the supply line to the power-limiting resistors, causing a short circuit to ground. In principle, this fault could be avoided by maintaining appropriate distances between the conductor tracks and ground, i.e., by making the conductor track "non-susceptible to short circuits." However, by using central current limitation, these measures are no longer necessary.

[0065] Of particular importance in connection with circuit arrangements for potentially explosive atmospheres are the distances between components and conductor tracks, which must not be less than certain minimum distances to avoid short circuits that can occur, for example, due to conductive dust particles. In this context, the design of the circuit arrangement with several separate circuit islands is particularly advantageous because smaller distances can be achieved within the circuit islands than between the circuit islands. Accordingly, the invention provides that the distances between the conductor tracks between individual circuit islands must not be less than a predetermined minimum distance, whereby this minimum distance is greater than the distance between the conductor tracks within the circuit islands.A further improvement can optionally be achieved - depending on the desired level of protection - by providing the circuit arrangement at least in some areas with an electrically insulating protective coating, since such protective coatings can further reduce the permissible distances between the conductor tracks. If necessary, a protective varnish can be used in the area of ​​the main board, i.e. the circuit arrangement on the main board can be coated with a protective varnish in some areas. For example, certain areas are left out, i.e. a protective varnish is omitted in certain areas, since the protective varnish can lead to impairments in certain components or the application of a protective varnish is not spatially possible in certain areas. However, it is also possible to omit a protective varnish entirely from the main board.

[0066] On the motherboard or in areas of the motherboard where no protective coating is provided, a specified initial minimum distance of, for example, 1.5 mm is not exceeded. This applies, for example, to the areas between individual circuit islands that are exposed without protective coating.

[0067] In the areas between individual circuit islands that are provided with a protective coating, a second minimum distance of, for example, 0.5 mm is maintained.

[0068] Within the circuit islands, the minimum distance can be further reduced so that a third minimum distance of, for example, 0.2 mm is maintained within the circuit islands, regardless of whether a protective coating is provided or not.

[0069] Overall safety is further increased by partially or completely covering or encasing the additional circuit board 9b with a protective coating, e.g., encapsulating it in a protective coating. Thus, it may be expedient to encapsulate the additional circuit board only on one side. This is not shown in the drawings.

[0070] In the illustrated embodiment with main board 9a and additional board 9b, it is also advantageous that the circuit arrangement can also be used without the additional board, specifically for applications outside of potentially explosive atmospheres. In this case, the current limiting device is omitted. A single voltage regulator is nevertheless provided on the main board, which consequently no longer needs to be designed with multiple redundancy. The circuit arrangement according to Fig. 2 therefore also works without the additional board, in which case the Fig. 2 shown bridges 25 must be fitted. In the circuit arrangement according to Fig. 6 For use outside potentially explosive areas, a voltage limiter 23' is provided, which in the explosion-proof version is not arranged on the main board 9a, since all voltage limiters in this embodiment are Fig. 6 and 7 are arranged on the additional board. In this case, too, the Fig. 6 shown bridges 25.

[0071] Furthermore, both the embodiment according to Fig. 2 as well as the embodiment according to Fig. 6An optionally available additional block, or an additional circuit island E10, which serves to differentiate between batteries. This circuit island, whose power is limited by a resistor (not shown), applies a controlled current to the battery pack, namely the load from driving the motor and the LEDs. The technology-related voltage drop can be used to determine which battery type is inserted, e.g., whether an alkaline or lithium battery or battery pack is inserted. The aforementioned power limitation between the protection island E10 and the protection island E1 is implemented via resistor R4.

Claims

1. A lubricant dispenser (1) comprising at least - a lubricant reservoir (2), - an electromechanical drive (7) that acts on at least one actuating element (4) to dispense lubricant from the lubricant reservoir (2), - a battery (8) which provides a battery voltage (VB), - a control board assembly (9) having at least a main board (9a) with an electronic circuit arrangement that comprises at least one central microcontroller (10) and additional electronic functional components, as well as conductor tracks (11), characterized in that the electronic circuit arrangement is divided into multiple circuit islands (E1 to E9), or comprises multiple circuit islands (E1 to E9), wherein some or all circuit islands are power-limited, and one or more of the circuit islands are power-limited by at least one power-limiting resistor (R1, R1', R2, R3) .

2. The lubricant dispenser according to Claim 1, characterized in that the respective power-limiting resistor (R1, R1', R2, R3) is a series resistor.

3. The lubricant dispenser according to Claim 1 or 2, characterized in that one or more circuit islands, preferably those without power limitation, are each equipped with a thermal fuse which is attached to the board in the region of the respective circuit island, for example, e.g. glued in place.

4. The lubricant dispenser according to any one of Claims 1 to 3, characterized in that the electromechanical drive (7) is designed as a direct-current motor, preferably as a brushless direct-current motor (BLDC), or comprises such a motor.

5. The lubricant dispenser according to any of Claims 1 to 4, characterized in that the spacing of the conductor tracks (11) between individual circuit islands does not fall below a specified minimum distance, wherein this minimum distance is preferably greater than the spacing of conductor tracks within the circuit islands themselves.

6. The lubricant dispenser according to any one of Claims 1 to 5, characterized in that the circuit arrangement is provided with, or connected to, a current-limiting device (22) that limits the total energy within the (entire) circuit arrangement.

7. The lubricant dispenser according to Claim 6, characterized in that the current-limiting device (22) is designed with multiple redundancies and preferably with multiple, e.g. at least three, current limiters (22a, b, c) which are connected in parallel, for example.

8. The lubricant dispenser according to Claim 6 or 7, characterized in that the current-limiting device (22) (additionally) comprises a fuse (24), e.g. a melting fuse.

9. The lubricant dispenser according to any one of Claims 1 to 8, characterized in that the circuit arrangement is provided with, or connected to, a voltage regulation device (23) which reduces the battery voltage (VB) to a regulated operating voltage (VR).

10. The lubricant dispenser according to Claim 9, characterized in that the voltage regulation device (23) is designed with multiple redundancies and preferably comprises multiple, e.g. three, voltage regulators (23a, b, c) which are connected in series.

11. The lubricant dispenser according to Claim 10, characterized in that the voltage regulator or the voltage regulators (23a, b, c) is / are each designed as a separate circuit island (E7, E8, E9) and separately power-limited, e.g. by a power-limiting resistor (R3) in each case.

12. The lubricant dispenser according to any of one of Claims 1 to 11, characterized in that the control board assembly (9) comprises, in addition to the main board (9a), an auxiliary board (9b) connected thereto, e.g. mounted on the main board.

13. The lubricant dispenser according to Claim 12, characterized in that the current-limiting device (22) is arranged on the auxiliary board (9b), wherein the current-limiting device (22) preferably limits the current flowing into the main board (9a).

14. The lubricant dispenser according to Claim 12 or 13, characterized in that the voltage regulation device (23) is partially or fully arranged on the main board and / or partially or fully arranged on the auxiliary board (9b), in that, for example, one or multiple voltage regulators (23b, c) are arranged on the auxiliary board (9b).

15. The lubricant dispenser according to Claim 14, characterized in that at least one voltage regulator (23a) is arranged on the main board (9a) and one or more voltage regulators (23b, c) is / are arranged on the auxiliary board (9b).

16. The lubricant dispenser according to Claim 14, characterized in that all voltage regulators (23a, b, c), e.g. all three voltage regulators (23a, 23b, 23c) are arranged on the auxiliary board (9b).

17. The lubricant dispenser according to any one of Claims 14 to 16, characterized in that all voltage regulators (23a, b, c) on the auxiliary board (9b) are equipped with a thermal fuse, wherein preferably a shared thermal fuse is glued to the auxiliary board across all voltage regulators.

18. The lubricant dispenser according to any one of Claims 1 to 17, characterized in that the circuit arrangement is partially or fully provided with an electrically insulating protective coating, e.g. with a conformal coating.

19. The lubricant dispenser according to Claim 18, characterized in that the circuit arrangement on the main board (9a) is partially coated with a protective coating, e.g. a conformal coating.

20. The lubricant dispenser according to Claim 17 or 18, characterized in that the auxiliary board (9b) is partially or fully provided with a protective coating, e.g. is partially or fully encapsulated in a protective coating, e.g. potted or injection-moulded.

21. The lubricant dispenser according to any one of Claims 1 to 20, characterized in that the spacing of the conductor tracks (11) - between individual circuit islands without a protective coating does not fall below a specified first minimum spacing of e.g. 1.5 mm and / or - between individual circuit islands with a protective coating does not fall below a second minimum distance of e.g. 0.5 mm and / or - within a circuit island does not fall below a third minimum distance of e.g. 0.2 mm, e.g. with or without a protective coating.

22. The lubricant dispenser according to any one of Claims 1 to 21, characterized in that the microcontroller (10) and additional functional components form a common (first) circuit island (E1), wherein the functional components in this circuit island (E1) are only supplied with voltage through the microcontroller.

23. The lubricant dispenser according to any one of Claims 1 to 22, characterized in that the circuit arrangement in one circuit island (E6), e.g. on the main board, comprises a motor controller (21) connected to the motor, which is connected to the non-reduced and unregulated battery voltage (VB), namely preferably without a power-limiting resistor and preferably with a thermal fuse.

24. The lubricant dispenser according to any one of Claims 1 to 23, characterized in that the circuit arrangement comprises, in one circuit island (E3), e.g. on the main board, a communication module (18) for wireless communication, e.g. a communication module for Bluetooth communication.

25. The lubricant dispenser according to any one of Claims 1 to 24, characterized in that the circuit arrangement is equipped with a board detection feature that detects whether an auxiliary board is being used, in that it automatically detects, for example, whether an auxiliary board is plugged into or soldered onto the main board.

26. The lubricant dispenser according to any one of Claims 1 to 25, characterized in that, in addition to the power limitation of one or multiple individual circuit islands, a power limitation is implemented between individual, interconnected circuit islands, e.g. by one or multiple intermediate resistors (R4, R5, R6, R7, R8, R9) arranged between two circuit islands.

27. A control board assembly (9) for a lubricant dispenser according to any one of Claims 1 to 26, wherein the control board assembly (9) has at least one main board (9a) with an electronic circuit arrangement with at least one central microcontroller (10) and additional electronic functional components and conductor tracks (11), characterized in that the electronic circuit arrangement is divided into multiple circuit islands (E1 to E9) or has multiple circuit islands, wherein some or all of the circuit islands are each power-limited.