Patent Description:
The invention further relates to an apparatus arranged for providing liquid from a storage container to a liquid intake device, which apparatus comprises a tank module.

A tank module with a tank and an inductive conductivity sensor is known from document <CIT>. The inductive conductivity sensor comprises at least one transmitter unit with a transmitter coil for generating an alternating field which generates an annular current in the liquid and at least one receiver unit with a receiver coil for receiving a receive signal generated via the annular current. One of the mentioned applications is fill level detection with respect to the tank.

Document <CIT> discloses a method of detecting the level of molten metal existing within a mold. According to a method disclosed in this document, a plurality of sets of transmission coils and receiving coils are oppositely disposed on the outsides of the mold walls, at intervals in the vertical direction in which the level of the molten steel changes.

Dosing systems implemented as a dosing station arranged for providing liquid from a storage container, like a canister, to a dosing device of the system have previously been disclosed. Such systems generally include an apparatus arranged for providing liquid from a storage container to a liquid intake device. One example of such an apparatus and dosing system is disclosed in <CIT>. The corresponding apparatus for providing liquid from a storage container of this dosing system comprises: (i) an extraction probe for extracting liquid out of the storage container; (ii) a tank module comprising a tank and an inductive conductivity sensor for determining a liquid level of a liquid in the tank, wherein the tank forms a buffer reservoir which is connected to the extraction probe; (iii) a feeding line connecting the buffer reservoir to a liquid outlet of the apparatus, which liquid outlet is adapted for establishing a connection to the liquid intake device; (iv) a venting line connecting the buffer reservoir with an air outlet of the apparatus; and (v) a support for mounting the apparatus on the storage container in such way, that the extraction probe extends through a liquid outlet of the storage container into the interior of said storage container.

A simple inductive conductivity sensor can only determine whether the liquid level of the liquid in the tank is lower or higher than a defined limit value of the liquid level.

Therefore, one object underlying the present invention is to provide an improved tank module, especially an improved tank module for an apparatus arranged for providing liquid from a storage container to a liquid intake device.

This object is achieved by the invention as defined by the independent claim.

The dependent claims detail advantageous embodiments of the invention.

According to various aspects of the invention, the tank module comprises a tank and an inductive conductivity sensor arranged for determining a liquid level of a liquid in the tank. It is provided that the inductive conductivity sensor comprises (a) at least one transmitter unit for generating an alternating field which generates one or more annular currents in the liquid and (b) at least one receiver unit for receiving a receive signal generated via the annular current or at least one of the annular currents, wherein the interior of the tank specifies by its shape different ring-like paths for enabling a plurality of annular currents, wherein for the formation of an annular current in the respective ring-like path an individual minimum liquid level is necessary, wherein the minimum liquid levels differ for the different ring-like paths. With such a tank module a plurality of predetermined liquid levels can be determined very precisely.

According to the invention as claimed, the interior of the tank comprises a first region being the main transmitting region of the transmitter unit and a second region being the main receiving region of the receiver unit, wherein both regions are located on each of the different ring-like paths.

According to the claimed invention, the two aforementioned regions are partially separated by a dividing structure of the tank.

In this embodiment the tank preferably comprises one or more channels through the dividing structure for providing the ring-like paths, wherein each channel is at a well-defined individual height. These different heights correspond to the different liquid levels to be determined.

In accordance with another aspect of the present invention, at least one part of the dividing structure is formed as a divider plate. Preferably, at least one of the channels is realized as a break-through in said divider plate.

In accordance with yet another aspect of the present invention, the tank comprises a first main part serving as an upper part and a second main part serving as a lower part of the tank, wherein the interior spaces of said main parts are connected by two passages separated from each other, wherein at least one of the passages comprises the first and second regions. In one embodiment one of the passages forms the first region and the other passage forms the second region.

Preferably the divider plate is located in the first main part of the tank.

In accordance with another aspect of the present invention, the transmitter unit comprises a transmitter device and a transmitter coil and the receiver unit comprises a receiver device and a receiver coil.

In this case the one passage is preferably surrounded by the transmitter coil and the other passage is surrounded by the receiver coil or only one of these passages is surrounded by both of these coils.

According to various aspects of the invention, the apparatus arranged for providing liquid from a storage container to a liquid intake device comprises:.

In other words, the apparatus according to these aspects of the invention is an apparatus adapted for direct installation at/on the storage container and for a connection to a liquid intake device like a dosing device comprising a dosing pump or any other liquid pumping device. The contact-free liquid level detector for detecting the liquid level in the tank/buffer reservoir takes up only little space and ensures proper function. Since the apparatus is mounted/installed on the storage container for the utilization phase only and not permanently, said apparatus can be used much more flexible.

On the other hand, due to this non-permanent installation, the apparatus preferably comprises safety measures for preventing a leakage of liquid from the tank/buffer reservoir via the venting line and the air outlet respectively. Therefore, the venting line and/or the connection of the venting line with the tank/buffer reservoir comprise(s) a waterproof (but breathable) membrane for preventing a leakage of liquid via the venting line. This membrane preferably is a waterproof, breathable fabric membrane, e.g. a Gore-Tex™ membrane. The major advantages of emptying a storage container by use of this kind of apparatus is that the liquid can be provided free from air or other gases (free of blow-holes), the storage container can be emptied almost completely, an out-of-liquid detection is automatically implied and the apparatus is movable and therefore very flexible in use. All these advantages are of particular value when providing hazardous chemicals from the storage containers.

According to a preferred embodiment of the present invention, the apparatus further comprises a sensing device for determining whether the apparatus is mounted at/on the storage container via the support. Preferably, the sensing device is formed as a button type sensing device with a "connected finger".

In accordance with another aspect of the present invention, the support for mounting the apparatus on the storage container is adapted for providing a connection with a nozzle (or tubular mouthpiece) forming the liquid outlet of the storage container. Many storage containers, like e.g. canisters and so-called save packages for chemical products, do have liquid outlets formed as nozzles. These kinds of nozzles often comprise external threads and/or additional collars. Many storage containers are equipped with standard-type nozzles showing these attributes. The support for mounting the apparatus on the storage container preferably uses further standard attributes like a cap nut arranged for a form fit with the external thread of the nozzle or lever arms arranged for a form fit with the collar surrounding the nozzle.

According to another preferred embodiment of the present invention, the extraction probe comprises a hollow needle, which hollow needle preferably is surrounded by a socket-like safety component. Such kind of extraction probe with a hollow needle (with a sharpened tip) is, e.g., known from a device for dispensing liquids from a storage container provided with a liquid outlet formed as a substantially nozzle or tubular mouthpiece, which device is described in document <CIT>. The needle is arranged for providing a fluidic connection to a suction lance installed in the interior of the storage container.

In general an external air venting pump may be connected to the venting line via the air outlet. According to a preferred embodiment of the present invention, the apparatus further comprises an air venting pump arranged in the venting line.

Preferably, the apparatus further comprises an activated carbon filter arranged in the venting line.

In accordance with another aspect of the present invention, the apparatus further comprises a non-return valve arranged in the feeding line. The non-return valve prevents a reflux/backflow of liquid in the feeding line from the liquid outlet back to the tank/buffer reservoir.

According to yet another preferred embodiment of the present invention, the apparatus comprises a sensor for measuring tilt angles of the apparatus with respect to gravity, especially an inclinometer or a (3D-)acceleration sensor. The sensor is preferably realized as a MEMS sensor (MEMS: Micro-Electro-Mechanical system).

According to yet another preferred embodiment of the present invention, the apparatus further comprises an electronic evaluation unit for evaluation of an out-of-liquid state of the storage container. Thereby the electronic evaluation unit is in signal connection to the contact-free liquid level detector. In other words, a signal line is connecting the electronic evaluation unit to the contact-free liquid level detector.

In accordance with yet another aspect of the present invention, the electronic evaluation unit further on is in signal connection to the sensing device. By use of this signal connection the electronic evaluation unit is able to take the mounting state of the apparatus into account. Preferably, the electronic evaluation unit or another evaluation electronic of the apparatus is in signal connection to the sensor for measuring the tilt angles of the apparatus with respect to gravity. The evaluated data from the sensor can, e.g., be used for controlling a safety shut-off of the air venting pump.

According to a preferred embodiment of the present invention, the electronic evaluation unit is part of a control unit, in signal connection to a control unit or at least connectable to an external control unit.

According to another preferred embodiment of the present invention, the electronic evaluation unit is in signal connection to the air venting pump. By use of this signal connection the electronic evaluation unit (or the control unit respectively) is able to perform an automatic venting step.

According to yet another preferred embodiment of the present invention, the apparatus further comprises an output device arranged for providing a signal like an out-of-liquid alarm signal. In the simplest case the output device is a warning lamp (e.g. an LED-light) and/or an alarm bell.

According to another preferred embodiment of the present invention, the contact-free liquid level detector is arranged for a capacitive measurement of the liquid level or an inductive measurement of the liquid level.

The present invention further refers to a liquid intake system comprising: (a) a liquid intake device including a pump; and (b) an apparatus arranged for providing liquid from a storage container to said liquid intake device, which apparatus is designed as an aforementioned apparatus. A suction connection of the liquid intake device is connected to the liquid outlet of the apparatus arranged for providing liquid from the storage container.

According to a preferred embodiment of the present invention, the liquid intake device is a dosing device comprising a dosing pump.

Additional details, features, characteristics and advantages of the object of the invention are disclosed in the figures and the following description of the respective figures, which - in exemplary fashion - show one embodiment and an example of a dispensing system according to the invention. In the drawings:.

<FIG> shows a schematic representation of a tank module <NUM> with a tank <NUM> and an inductive conductivity sensor <NUM> arranged for determining a liquid level <NUM> of liquid in the tank <NUM>. The inductive conductivity sensor14 comprises at least one transmitter unit <NUM> for generating an alternating electrical field which generates one or more annular currents in the liquid and at least one receiver unit <NUM> for receiving a receive signal generated via the annular current or at least one of the annular currents. The tank <NUM> comprises a first main part <NUM> serving as an upper part and a second main part <NUM> serving as a lower part of the tank <NUM>, wherein the interior spaces of said main parts <NUM>, <NUM> are connected by two passages <NUM>, <NUM> separated from each other, wherein one of the passages <NUM> forms a first region <NUM> being the main transmitting region surrounded by a transmitter coil of the transmitter unit <NUM> and the other passage <NUM> forms a second region <NUM> being the main receiving region surrounded by a receiving coil of the receiver unit <NUM>.

The two regions <NUM>, <NUM> are partially separated by a dividing structure <NUM> of the tank <NUM>, which dividing structure <NUM> comprises a divider plate <NUM> located in the first main part <NUM> of the tank <NUM>. The interior of the tank <NUM> specifies by its shape different ring-like paths <NUM>, <NUM> for enabling a plurality of annular currents (current loops), wherein for the formation of an annular current in the respective ring-like path <NUM>, <NUM> an individual minimum liquid level is necessary. For the different ring-like paths <NUM>, <NUM> the minimum liquid levels differ. For this purpose the tank <NUM> comprises channels <NUM>, <NUM> through the dividing structure <NUM> for providing the ring-like paths having the different minimum liquid levels, wherein each channel is at a well-defined individual height h1, h2 defining a first and a second filling level. In the shown example the channels <NUM>, <NUM> are realized as a break-through in the divider plate <NUM>.

An annular current along the first ring-like path <NUM> ("C1-loop") is associated with a cell constant C1 (with C1 = I1 / A1, wherein I1 is the corresponding current and A1 the cross section of path <NUM>). An annular current along the second ring-like path <NUM> ("C2-loop") is associated with a cell constant C2 (with C2 = I2 / A2, wherein I2 is the corresponding current and A2 the cross section of path <NUM>).

The following function results:
When the first main part (upper part) <NUM> is not filled, no annular currents will be generated and no conductivity will be measured ("LL": low level-state of the tank <NUM>). When the interior of the tank <NUM> is filled up to the first filling level h1: the cell constant C1 is active. When the interior of the tank <NUM> is filled up to a filling level <NUM> with h2 > l > h1 ("PLL": pre low level-state of the tank <NUM>): because of the divider plate <NUM> only cell constant C1 is active. In case the divider plate <NUM> is over flooded, that means if the interior of the tank <NUM> is filled up to the second filling level h2: C1 and C2 are active ("HL": high level state of the tank <NUM>).

<FIG> shows a sectional view of a specific design of the tank module <NUM> described schematically in <FIG>. In this embodiment only one of the passages <NUM>, <NUM>, namely passage <NUM>, is surrounded by both of these coils (the coil of the transmitter unit <NUM> and the coil of the receiver unit <NUM>). The tank module <NUM> is designed for use as a buffer reservoir a contact-free liquid level detector for detecting the liquid level in said buffer reservoir in an apparatus <NUM> described hereafter in <FIG>.

The illustration in <FIG> shows an apparatus <NUM> arranged for providing liquid from a storage container <NUM> to a liquid intake device like a dosing device. The storage container <NUM> is a canister, a safe package canister to be precise. The storage container <NUM> comprises a liquid outlet <NUM> formed by a nozzle <NUM> on the upper side of the container <NUM> and an integrated suction lance (suction pipe) <NUM> in the interior of the container <NUM>. The suction lance <NUM> extends from the bottom area of the interior (not shown) up to the liquid outlet <NUM> of the container <NUM>, which outlet <NUM> is closed by a membrane <NUM>.

The apparatus <NUM> arranged for providing liquid from the storage container <NUM> comprises a support <NUM> for mounting the apparatus <NUM> on the liquid outlet <NUM> of said storage container <NUM> so that an extraction probe <NUM> extends with a hollow needle <NUM> through said liquid outlet <NUM> of the storage container <NUM> and the membrane <NUM> closing this outlet <NUM> into the interior of said storage container <NUM>, or more precisely in the upper opening of the suction lance <NUM>. The extraction probe <NUM> is arranged for extracting liquid out of the storage container <NUM>. Further on, the apparatus <NUM> comprises the tank module <NUM> with the tank <NUM> forming a buffer reservoir connected to the extraction probe <NUM> via a suction pipe <NUM> and the sensor <NUM> forming a contact-free liquid level detector for detecting the liquid level in the buffer reservoir.

The apparatus <NUM> further comprises a feeding line <NUM> connecting the buffer reservoir (tank <NUM>) to a liquid outlet <NUM> of the apparatus <NUM>. A non-return valve <NUM> is arranged in the feeding line <NUM> and the liquid outlet <NUM> is adapted for establishing a connection to (the suction line of) a liquid intake device like a dosing device (not shown). Further on, the apparatus <NUM> comprises a venting line <NUM> connecting the buffer reservoir (tank <NUM>) to an air outlet <NUM> of the apparatus <NUM>, wherein the connection of the buffer reservoir (tank <NUM>) to the venting line <NUM> comprises a waterproof breathable membrane <NUM> for preventing a leakage of liquid via the venting line <NUM> and the air outlet <NUM>. Further on an activated carbon filter <NUM> and an air venting pump (purge pump) <NUM> are arranged in the venting line <NUM> too.

The apparatus <NUM> further comprises a sensing device <NUM> for determining whether the apparatus <NUM> is mounted on the storage container <NUM> via the support <NUM>. The sensing device <NUM> is formed as a button type sensing device with a "connected finger" coupled to a magnet, a spring and a magnetic field sensor (e.g. a hall element) for detecting the position of the magnet. Further on, the apparatus <NUM> includes an electronic evaluation unit <NUM> for evaluation of an out-of-liquid state of the storage container <NUM> (and optional other states either), wherein the electronic evaluation unit <NUM> is in signal connection to the contact-free liquid level sensor <NUM>, to (the magnetic field sensor of) the sensing device <NUM>, the venting pump <NUM>, an external control unit <NUM> via a signal connection <NUM>, and an output device <NUM> of the apparatus <NUM> being an OP mode LED via signal lines <NUM>. Said external control unit <NUM> is, e.g., the control unit of a higher level system including the apparatus <NUM> and the above mentioned (but not shown) liquid intake device comprising a pump fluidically connected to the feeding line <NUM> via the liquid outlet <NUM>. The external control unit <NUM> controls -among others- the pump of the liquid intake device.

One main application for this kind of apparatus <NUM> is providing (liquid) chemical products from a storage container <NUM> to a corresponding liquid intake device. Some of these chemical products are very aggressive. As a result the demand for the aforementioned safe packages is increasing. Such safe packages typically do not have an opening where a state of the art suction lance could be placed. The safety packages instead have a coupling system on top of the storing container (product canister) <NUM>. Low level detection is critical with regard to a change of the storage container. The apparatus <NUM> enables a contactless out of product detection. The full automatic venting technology ensures that the product lines will be refilled after a replacement of the empty storage container <NUM>. This venting will start automatically after a reconnection to a new container/canister.

Claim 1:
A tank module (<NUM>) comprising a tank (<NUM>) and an inductive conductivity sensor (<NUM>) arranged for determining a liquid level (<NUM>) of liquid in the tank (<NUM>), wherein the inductive conductivity sensor (<NUM>) comprises at least one transmitter unit (<NUM>) for generating an alternating field which generates one or more annular currents in the liquid and at least one receiver unit (<NUM>) for receiving a receive signal generated via the annular current or at least one of the annular currents, wherein the interior of the tank (<NUM>) specifies by its shape different ring- like paths (<NUM>, <NUM>) for enabling a plurality of annular currents, wherein for the formation of an annular current in the respective ring-like path (<NUM>, <NUM>) an individual minimum liquid level is necessary, wherein the minimum liquid levels differ for the different ring-like paths (<NUM>, <NUM>), characterized in that the interior of the tank comprises a first region (<NUM>) being the main transmitting region of the transmitter unit (<NUM>) and a second region (<NUM>) being the main receiving region of the receiver unit (<NUM>), wherein both regions are located on each of the different ring-like paths (<NUM>, <NUM>) and are separated by a dividing structure (<NUM>) of the tank.