DEVICE FOR CAPTURING A MEDIA PRINT

Description

[0001] The present invention relates to a device for detecting a medium pressure within a flowable medium contained in a container, comprising a shield and a pressure sensor associated with or connected to the shield, wherein the shield shields the pressure sensor at least on one side from turbulences occurring in the medium, for example during filling or emptying of the container, wherein the pressure sensor communicates with an external data processing unit for evaluating sensor data and the shield is connected to a pump lance of a container pump in the region of a pump base and forms a measuring chamber in which the pressure sensor is accommodated.

[0002] Such a device is already known from US 2011 / 181426 A1. This device is for detecting the pressure within a fuel tank. In this case, the fill level is measured and electronically transmitted via a sensor that is electronically linked to an RFID chip.

[0003] Furthermore, reference is made to DE 100 60 007 A1. This concerns a pressure sensor in a fuel tank, which is intended to detect the fuel level and is intended to be protected by a shield against surges in the moving vehicle.

[0004] From DE 102 26 523 A1, it is also known to arrange a pressure line in a pump lance that has an opening into the pumping tank at a minimum fill level. Due to a pressure drop when the minimum fill level is undershot, an external pressure sensor can at least draw some conclusions about the fill level.

[0005] DE 36 39 455 A1 concerns a fully electronic level measurement of liquids and gases, for which flat pressure sensors are used.

[0006] Furthermore, EP 1 391 612 B1 describes determining the height of the liquid level above a pressure sensor using a pressure sensor associated with the pumping mechanism described therein. However, according to the teaching of EP 1 391 612 B1, the new liquid level can only be determined after each pump run, not during the run.

[0007] The reason for this is that the pressure sensor is based on measuring static pressure. To measure the fill level of a container, one usually tries to place the pressure sensor at the lowest point of the container so that it can determine the fill level relative to this lowest point. However, this lowest point is also particularly advantageous for locating the pumps for completely emptying the container, for example, in the so-called pump sump.

[0008] If one or more pump lances are inserted into the container and begin pumping the medium from the immediate vicinity of the pressure sensor, where the pressure sensor is also located, the pressure sensor will no longer be able to operate under its ideal conditions, i.e., at static pressure. Rather, its measurement results will be significantly distorted due to the movement of the medium. This effect can be explained using the Bernoulli equation: P t = P dynamisch + P statisch

[0009] When the pump is switched off, the fluid is at rest and the dynamic pressure component is zero. In this special case, the following applies: P t = P statisch

[0010] When the pump is switched on, however, the fluid in the container is set in motion. Since the resulting losses are minimal, a constant total pressure Pt can be assumed, while the static pressure P static drops during the pumping process. If a level measurement is then performed as described, an incorrect fill level will be displayed due to this drop in static pressure.

[0011] Particularly in more complex systems where the fill levels in containers are to be subject to permanent monitoring, this can lead to false alarms if the pressure measurement suggests that a container containing, for example, a production-relevant and critical medium is almost completely empty.

[0012] Against this background, the present invention is based on the object of creating a device for detecting a media pressure within a flowable medium held in a container, which device also returns correct measured values ​​with regard to the filling level resulting from the static component of the media pressure during the pumping process.

[0013] This object is achieved by a device according to the features of claim 1. Further useful embodiments of such a device can be found in the subclaims.

[0014] According to the invention, a static environment is created around the pressure sensor that is as flow-free as possible so that static pressure can be measured. For this purpose, the pressure sensor is connected to a shield, which in the simplest case can be a shielding plate. The shield can have different shapes and sizes and be made of different materials, with the choice of material also being largely determined by the medium. A key aspect here is that the shield is selected to be large enough to define a flow-free area within the medium in which the pressure sensor is housed.

[0015] In this way, the pressure sensor is shielded from surrounding flows and, despite its possible proximity to the pump base, is at least located in a largely static medium. Depending on the number and height of the wall sections surrounding the pressure sensor, the proportion of static pressure in the total pressure can be influenced to a certain extent. However, one or more openings can also be provided in the shield with some advantage, so that even if the pressure sensor is more or less completely surrounded by the shield in a cup-shaped manner, the level can still drop below the upper edge of the shield. The shield is open at the top and has a compensation hole in the lower area as a through-opening.

[0016] The shield is mounted directly on a pump lance and, together with its wall, forms a measuring chamber in which the pressure sensor is housed. This is done in the area of ​​the pump base to ensure the closest possible proximity to the lowest point in the tank.

[0017] The sensor data is communicated to a data processing unit, which determines the fill level from the raw data of the pressure sensor and processes it further as required, i.e. calculates it with container information, compares it with limit values ​​and forwards the results of its calculations to process computers or interfaces.

[0018] The design of the measuring chamber can be subject to various specifications; with some advantage, the pressure sensor can be completely enclosed by the measuring chamber, so that it is completely subject to the influence of the at least approximately purely static pressure within the measuring chamber. Additionally, through-openings can also be provided in the outer wall sections to avoid completely isolating the measurement within the measuring chamber from the container, but rather to allow the medium to penetrate the measuring chamber. In particular, there should essentially be no housing part above the pressure sensor, but only the medium, in order to allow the static pressure to be measured to act on the pressure sensor.

[0019] The pressure sensor itself can be connected to the data processing unit, for example, via a cable connection. Such a cable connection can serve to supply power to the pressure sensor on one side, but in the opposite direction, it can also transmit the pressure sensor data to the data processing unit. In such a configuration, when inserting the pump lance into the container, the pressure sensor can first be plugged into the measuring chamber and then the cable can be routed along the pump lance to the data processing unit.

[0020] In a further embodiment of the pump lance, the cable connection is directly and firmly connected to the pump lance and is led out of the container in a holder running along the pump lance.

[0021] In the event that the pumping tube is screwed to the tank opening by means of a union nut, such integration into the casing of the pump lance eliminates the need for a separate feedthrough for the cable connection out of the tank.

[0022] Alternatively or additionally, the pressure sensor can also incorporate an energy storage device in the form of a battery or a rechargeable accumulator. In this case, the pressure sensor draws its power directly from the energy storage device and also features wireless communication means, such as a wireless radio module such as Bluetooth or a similar technology. In this case, measurement data is transmitted wirelessly to the data processing unit, eliminating the need for a cable connection.

[0023] This solution can be further developed by assigning an induction coil to the pressure sensor for power supply. A voltage is induced in this coil to power the pressure sensor, as well as to operate the wireless communication module or to charge the energy storage device, by assigning an excitation magnet, in particular a permanent magnet, to the pump rotor. The rotation of the pump rotor, driven by the pump motor, thus powers the pressure sensor, without requiring a separate cable routing.

[0024] Furthermore, in this configuration, the pressure sensor can easily detect whether the pump is active. This is essential if the pressure sensor is also intended to detect unwanted withdrawals due to theft or leakage. If the fill level changes without the excitation magnet moving, an alarm signal can be issued, which can be evaluated and interpreted by the data processing unit. If multiple pumps are operated on the same tank, a further check can be performed to determine whether another pump is operating. If this is not the case, the data processing unit will trigger an alarm.

[0025] The data processing unit, for its part, can be organized in different ways. Since the present invention assumes that the data processing unit is only assigned to a closed system, it can be assigned to the pumping station, the pump motor, or the container.

[0026] In a first case, in which the data processing unit is connected to the container, it can have container information based on a one-time assignment, for example by reading an RFID chip of the container or by storing it in a read-only memory of the data processing unit. The container information can include data such as the volume, the fill level, and possibly also restrictions regarding media, among other things. Since the data processing unit remains directly on the container, this information does not change easily. If the data processing unit now receives sensor data from the pressure sensor, this can be converted based on the container information, for example from a pressure taking the medium into account into a fill level, and from a fill level taking the total volume into account into a fill quantity. This also makes it easier to assess the leaks mentioned above.

[0027] However, if the data processing unit is only temporarily assigned to the container, for example due to a connection to the pumping station or pump motor, it makes sense to read in the container information. For this purpose, the data processing unit can have suitable means for reading in container information.

[0028] Specifically, these means for reading container information can be near-field communication means used to read an information carrier within range. This could, for example, be an RFID chip on which the container information is stored, and which engages an RFID reader unit when the pumping station is connected to the container. It is irrelevant whether the RFID chip directly stores all the necessary container information or whether the RFID chip merely carries a unique identifier, which the data processing unit can use to obtain the container information from another source, possibly by accessing a database.

[0029] Finally, it is useful to enable the fastest possible identification and location of the container, especially in the event of a leak alarm. For this purpose, the pressure sensor can, if necessary, incorporate geolocation features, such as triangulation, or even receive and transmit a GPS signal.

[0030] The invention described above is explained in more detail below using an exemplary embodiment.

[0031] It shows Figure 1 shows a container in which a pump motor with pumping mechanism is used, in a cross-sectional view with a wireless pressure sensor, and Figure 2 shows the container according to Figure 1 in a cross-sectional view with a wired pressure sensor.

[0032] Figure 1shows a cross-sectional view of a container 2 for holding flowable media. The container 2 has a container opening 3 in the center of its top side, through which medium 4 can be removed from or introduced into the container 2.

[0033] A pumping unit 7 with a pump motor 1 mounted thereon is inserted into the container 2 and screwed into the container opening 3 by a union nut. In addition to the union nut, the pumping unit 7 comprises a pump lance 8, which extends into the container 2 to a lowest point of the container 2, which is designed approximately as a pump sump 5. Operation of the pump motor 1 activates a pump rotor 9 located in the pump lance 8, which pumps the medium 4 out of the container 2 via an outlet not shown in detail here.

[0034] In order to be able to determine the fill level in the container 2, a pressure sensor 14 is assigned to the pump lance 8 in the area of ​​a pump base 10, which measures the static pressure in the area of ​​the pump sump 5 in order to draw conclusions about the fill level. For this purpose, the pressure sensor records the static pressure around the pump base and transmits its sensor data wirelessly via a Bluetooth connection to a data processing unit 17, which is arranged on the pumping station 7. Both communication partners have a communication interface, via which wireless communication is possible. The pressure sensor 14 is powered by a battery (not described in detail here), which is charged via an induction coil (not shown in detail). The exciter here is an excitation magnet 16, which is assigned to the pump rotor 9 and generates a constantly changing magnetic field due to its movement.

[0035] Since static pressure around pressure sensor 14 only exists when pump rotor 9 is stationary, pressure sensor 14 is housed in a measuring chamber 11, which acts as a shield separating medium 4 from pressure sensor 14. Although measuring chamber 11 has an upper open side 13 and a passage opening 12 on its underside, so that pressure sensor 14 not only detects a local chamber pressure within measuring chamber 11, the dynamic pressure component, which reduces the static pressure component, can be kept as low as possible, and pressure sensor 14 can be isolated from the effects of dynamic pressure. This enables reliable measurement even when pump rotor 9 is running.

[0036] Since the evaluation of the sensor data from pressure sensor 14 requires further information about container 2, this information must be available for suitable evaluation by the data processing unit 17. For this purpose, the latter has an RFID reader 18, which interacts with an RFID chip 6 of the container 2 and can be read when the pumping unit 7 is inserted into the container 2. The RFID chip 6 stores a unique identifier for the container 2 or its design, so that the data processing unit 17 can obtain all required container information about the container 2.

[0037] Figure 2 shows a variant of the Figure 1, in which, on the one hand, the data processing unit 17 is directly assigned to the container 2, and, on the other hand, the data processing unit 17 communicates with the pressure sensor 14 via a cable connection 15. Because the data processing unit 17 is permanently connected to the container, the container information of the container 2 is already permanently stored in the data processing unit 17. Reading in the container data, for example, when inserting the pumping unit 7 into the container opening 3, can thus be omitted.

[0038] The cable connection 15 to the pressure sensor 14, however, can be established when the pump tube 7 is inserted, so that the pressure sensor 14 can communicate with the data processing unit 17 via the cable connection and receive power from there. If necessary, the cable connection 15 can be integrated directly into the casing of the pump lance 8 to achieve a defined route for the cable connection 15.

[0039] The above describes a pumping station equipped with a pressure sensor that allows static pressure measurement even during pumping operation. This is achieved by accommodating the pressure sensor in a measuring chamber, where it is shielded from fluid turbulence. LIST OF REFERENCE SYMBOLS

[0040] 1 Pump motor 2 Tank 3 Tank opening 4 Medium 5 Pump sump 6 RFID chip 7 Pumping mechanism 8 Pump lance 9 Rotating shaft with impeller 10 Pump base 11 Measuring chamber 12 Passage opening 13 Open side 14 Pressure sensor 15 Cable connection 16 Excitation magnet 17 Data processing unit 18 RFID reader

Claims

1. A device for sensing the pressure of a medium within a fluid medium (4) received in a container, comprising a screen and a pressure sensor (14) associated with or joined thereto, wherein the screen shields the pressure sensor (14) at least on one side from swirls formed in the medium (4), for example during filling or emptying of the container (2), wherein the pressure sensor (14) communicates with an external data-processing unit (17) for evaluation of sensor data, and the screen is designed to be connectible to a pump lance (8) of a container pump in the region of a pump foot (10) and, in the connected state, forms together with said pump lance a measuring chamber (11) in which the pressure sensor (14) is received, wherein the screen is large enough to define a flow-free region within the medium and, in the connected state, is open at the top and has a compensating bore as a through-opening in the lower region.

2. The device according to claim 1, characterized in that the screen forms a measuring basket or a measuring chamber (11) which surrounds the pressure sensor (14) on multiple sides.

3. The device according to any one of the preceding claims, characterized in that the pressure sensor (14) is data-connected by means of a cable connection (15) to the data-processing unit (17) and / or is supplied with voltage thereby.

4. The device according to claim 3, characterized in that the cable connection (15) is designed such that it can be integrated into a jacket of the pump lance (8).

5. The device according to any one of claims 1 and 2, characterized in that the pressure sensor (14) has an energy store and is data-connected to the data-processing unit (17) via a wireless communication link.

6. The device according to any one of the preceding claims, characterized in that the pressure sensor (14) has an induction coil for voltage supply, in which a supply voltage and / or charging voltage for the energy store of the pressure sensor (14) is induced by an exciter magnet (16) joined to a rotor shaft (9) rotating in the pump lance (8).

7. The device according to claim 6, characterized in that the pressure sensor (14) signals to the data-processing unit (17) that the rotor shaft (9) is operating in the event of excitation by the exciter magnet (16).

8. The device according to any one of the preceding claims, further comprising the data-processing unit (17), characterized in that the data-processing unit (17) is designed such that it can be joined to the pump lance (8) or to an external pump motor (1) and has means for reading container information for evaluation of the sensor data of the pressure sensor (14).

9. The device according to claim 8, characterized in that the means for reading container information is a near-field communication unit which reads out information from information carriers of the container (2) which are preferably arranged in the region of the container opening.

10. The device according to claim 9, characterized in that an RFID reader unit (18) which reads from an RFID chip (6) on which container information is stored is used as the near-field communication unit.

11. The device according to any one of the preceding claims, further comprising the data-processing unit (17), characterized in that the data-processing unit (17) is designed such that it can be joined to the container (2) and possesses container information for evaluation of the sensor data of the pressure sensor (14).

12. The device according to any one of the preceding claims, further comprising the data-processing unit (17), characterized in that the pressure sensor (14) and / or the data-processing unit (17) are associated with means for geolocation.