EP3721779A1 - Cleaning trolley with a metering device and method for metering - Google Patents

Abstract

A cleaning trolley with a dosing device (18) for surface cleaners comprises a mixing container (20) that can be filled with any amount of water up to a maximum amount, at least one storage container (12; 14) for surface cleaning agents and a measuring cell (24) in the mixing container (20) for determining the conductance of the mixture, a computing unit (28) being provided which compares the conductance determined by the measuring cell (24) with a given conductance and outputs a signal when the given conductance is reached.

Description

Field of invention

The invention relates to a cleaning trolley with a metering device for surface cleaners and a method therefor.

State of the art

In professional cleaning applications, the cleaning liquor, i.e. a mixture of surface cleaner in water, made on site. Often only a concentrate of the surface cleaner is carried on conventional cleaning trolleys, while the water required to produce the mixture is handled by the cleaning staff on site due to the otherwise high weight to be carried, e.g. in toilet rooms or kitchens. The cleaning solution is usually dosed manually, using dosing aids such as measuring cups or discrete amounts of surface cleaner that is already packaged in individual portions or that can be dispensed in defined individual portions when added to water.

The problems with manual dosing are, on the one hand, the unknown amount of water, on the other hand, the need to clean certain cleaning objects in areas with different dosages, for example in order to use an antiseptic effect of a surface cleaner in a particularly targeted manner at certain points. If there are strict guidelines here, the individual cleaning staff are usually overwhelmed when calculating the correct dosage. Sometimes it is even impossible to do that Determine the dosing amount with the required accuracy because the amount of water is unknown.

Presentation of the invention

The invention is based on the object of proposing a cleaning trolley and a method for dosing a surface cleaner on a cleaning trolley, with which it can be ensured that a cleaning person on site correctly carries out the dosage.

This object is achieved with a cleaning trolley with the features of claim 1 and a method for dosing a surface cleaner on a cleaning trolley according to claim 7. Preferred embodiments are described in the remaining claims.

The cleaning trolley according to the invention with a dosing device for surface cleaner comprises a mixing container that can be filled with any amount up to a maximum amount of water specified by the volume of the mixing container, in particular for receiving or containing a mixture of water and surface cleaner, (at least) one storage container for (at least . One or more different) surface cleaners and a measuring cell (preferably in the mixing container) to determine the conductivity of the mixture (of water and surface cleaner), with a computing unit being provided that converts the conductivity (actual value) determined by the measuring cell with a specified conductivity (Target value) compares and outputs a signal when the specified conductivity is reached.

In other words, automatic or semi-automatic dosing takes place directly on the cleaning trolley, which makes use of the fact that, with increasing addition of surface cleaner to a mixing container filled with any amount of water, the conductivity of the Mixture changed and the desired concentration of surface cleaner in the water is characterized by a certain conductance that is stored in the computing unit. If this target value is reached, the computing unit outputs a signal. The signal can be processed with semi-automatic dosing, in which the cleaning staff stops adding the surface cleaner as soon as the signal has been issued. In the case of an automatic dosing device, the signal is directed to a dosing device which stops the supply of surface cleaner to the mixing container.

According to a preferred embodiment of the invention, there is automatic metering. For this purpose, the cleaning trolley further comprises a metering element, preferably a metering pump, for adding the surface cleaner from the storage container to the mixing container in order to produce a mixture of water and surface cleaner by conveying the surface cleaner into the mixing container. The arithmetic unit ends the energy supply to the metering pump when the specified conductance is reached.

According to a preferred embodiment, the cleaning trolley further comprises a mixing device (for mixing water and surface cleaner) in the mixing container. This serves to reduce and ideally eliminate differences in concentration when adding surface cleaner locally to the mixing container, so that the conductivity measured at the measuring cell is as precise as possible.

The cleaning trolley preferably further comprises an input device for user-controlled input of a desired concentration of surface cleaner, as well as a storage device in which the conductance values of one or more surface cleaners are stored depending on their concentration or a calculation algorithm for Determination of the conductivity is stored according to the desired concentration.

The user can enter the type of surface cleaner and / or the desired concentration via the input device. Using the conductivity values stored in the memory device as a function of the concentration of one or more different surface cleaners, or by storing suitable calculation algorithms for determining the conductivity value on the basis of a desired concentration, the correct dosage can be triggered by the input of the user, with different surface cleaners and, moreover, different concentrations of these surface cleaners can be used in order to be able to achieve an optimal cleaning result adapted to the individual cleaning situation.

The cleaning trolley preferably also has a digital interface to the computing unit for entering the concentration and / or the type of surface cleaner.

The use of a digital interface makes it possible to avoid sources of error in the user-controlled input by the cleaning staff. The corresponding input can be made either via a processing unit installed centrally in the object to be cleaned, or via a PDA (Personal Digital Assistant) carried by the cleaning staff, which allows, for example, weather-dependent individualization of the cleaning tasks and thus the correct performance of special tasks Carrying out work to be carried out regularly, but only to be carried out at certain time intervals. For example, in addition to cleaning tasks that have to be carried out regularly, there may also be special tasks that have to be performed at longer intervals, such as cleaning glass surfaces. Such special specifications can be made via the digital interface to the computing unit which takes on the task of not only informing the cleaning staff about the work to be carried out, but at the same time also informing them about the cleaning agent to be selected and regulating its correct dosage.

According to a preferred embodiment, the concentration of the surface cleaner can be predetermined as a function of the position of the cleaning trolley, the current position of the cleaning trolley being recorded by a central processing unit installed in the object to be cleaned. In other words, a suitable position determination can be used to determine in which room or building section the cleaning trolley is moving, in order to then enable the correct concentration of surface cleaner in the form of manual or automatic dosing.

The method according to the invention for dosing a surface cleaner on a cleaning trolley comprises the steps of a continuous measurement of the conductance of a mixture of water and surface cleaner while the surface cleaner is being added to the mixing container, the transmission of the measured conductance to a computing unit and the output of a signal by the computing unit, as soon as a master value stored or entered in the processing unit has been reached.

According to a preferred embodiment of the method, this further comprises the introductory step of measuring the conductance of the water and inputting the conductance as a reference value to the computing unit. In other words, the conductivity of the pure water is measured before the surface cleaner is added, because depending on the locally different water quality, such as the amount and type of minerals, there are different conductivity values of the pure water, which when using an algorithm to calculate the desired concentration in Depending on the conductance can be taken into account in the calculation equation. This measure can further improve the accuracy of the dosage.

Automatic metering is also the preferred variant in the method according to the invention, the operation of a metering pump for adding surface cleaner to the mixture being automatically stopped as soon as the signal has been output by the processing unit.

Brief description of the drawings

Fig. 1

schematisch einen Reinigungswagen mit einer Dosiereinrichtung zeigt; und

Fig. 2

ein Beispiel für die Veränderung des Leitwerts abhängig von der Konzentration eines Oberflächenreinigers und der Wasserqualität darstellt.

The invention is described below purely by way of example with reference to the figures, wherein

Fig. 1

shows schematically a cleaning trolley with a metering device; and

Fig. 2

represents an example of the change in the conductance depending on the concentration of a surface cleaner and the water quality.

Ways of Carrying Out the Invention

In Fig. 1 a cleaning trolley 10 is shown schematically, which is deliberately shown only schematically, since the geometry of the cleaning trolley can be selected as desired, as soon as the core components described below for the dosage of surface cleaner are available.

The cleaning trolley has a storage container 12 for surface cleaner, which is provided as a liquid concentrate. Alternatively, it is possible to equip the cleaning trolley with one or more additional storage containers 14. The storage containers 12, 14 each have an outlet 16 through which the surface cleaner can Storage container is conveyed in the direction of a metering element 18. In the schematic representation according to Fig. 1 only a single metering element 18 in the form of a metering pump is provided for the two reservoirs 12, 14. However, it should be clear that, on the one hand, each individual storage container can be connected to a separate metering device, especially if the individual surface cleaners cannot be mixed with one another and undesirable precipitations or flocculations or undesirable chemical reactions between individual surface cleaners can occur. In the simplest case, however, the flow connections between the outlets 16 and the metering elements open into a common metering pump.

It should also be clear that the metering device does not necessarily have to be a pump. At the in Fig. 1 The arrangement shown, in which the storage containers 12, 14 for surface cleaners are arranged higher up on the carriage 10 than the mixing container 20, the conveyance of the surface cleaner from the storage container to the mixing container can take place exclusively under the influence of gravity. In this case, the metering element can be a valve that can either be opened and closed manually by the user, or, in the case of automatic metering, is operated automatically, for example by being designed as a solenoid valve.

The mixing container 20 can either be removed from the cleaning trolley 10, or it has a filling nozzle with which cleaning liquid can be discharged from the mixing container into a suitable output vessel, in the simplest case into a tub or a bucket. This case is also of interest because after a mixture has been produced in the mixing container 20, only part of the cleaning liquor is removed from the mixing container, and pure water is then refilled into the mixing container. This situation is for the user it is no longer apparent which concentration of surface cleaner is in the mixing container, which underlines the advantage of the dosage according to the invention.

A feed channel 22, which connects the metering element 18 to the interior of the mixing container 20, ends in the mixing container 20. When a plurality of storage containers for surface cleaners and a plurality of metering elements are provided, a plurality of supply channels 22 are also to be provided, which in the simplest case can be designed in the form of a hose.

In the mixing container 20 there can also be a mixing device (38) which, in the simplest case, is designed as a stirrer and ensures that the concentration differences of surface cleaner are as small as possible within the mixing container. The mixing device can be coupled to the metering pump 18 via a connection so that the mixing device 38 is always operated when the metering element 18 conveys surface cleaner in the direction of the mixing container 20.

In the mixing container 20 there is a measuring cell 24 at a suitable location, with the aid of which the conductance of the mixture in the mixing container 20 is measured. The measuring cell 24 is connected to a computer unit 28 with a connected display 30 via a signal connection, in the simplest case via cabling 26. Via the display 30, which can also be an input device and can be in the form of a touchpad, for example, the user can enter data, such as the desired type of surface cleaner and the desired concentration, and also receive information.

The computing unit 28 has a permanent memory 34 in which either calculation algorithms for the desired conductance of the mixture based on a predetermined concentration of surface cleaner are stored, or empirically determined conductance values at specific concentrations are entered in the form of a mapping, between which can be interpolated .

The arithmetic unit 28 receives information about the conductivity determined by the measuring cell 24 during a dosing process and compares this actual value with a nominal value that can be taken directly from the memory 34 or on the basis of the value pairs contained in the memory 34 between concentration and conductivity in the Arithmetic unit is interpolated.

If the actual value of the conductivity has reached the nominal value of the conductivity during the dosing, this can either be communicated to the user in the display or can be communicated via a suitable signal output unit, for example in the form of a notification tone, so that the user can manually stop the operation of the dosing element 18 . In the case of automatic dosing, however, an automatic control loop can be present in the same way, according to which the computing unit 28 prevents further dosing of surface cleaner via the dosing element 18 via the signal connection 36 when the setpoint is reached. Of course, in order to increase the accuracy, the computing unit can also take into account that after the dosing element 18 has been closed, there is still a residual amount of surface cleaner in the supply channel 22 and therefore end the dosing somewhat earlier.

Centrally in the object to be cleaned, a central processing unit 40 can be provided, which coordinates the cleaning tasks to be carried out by different cleaning staff with their respective cleaning trolleys and via a communicates wireless connection with the interfaces 32 of the cleaning trolleys. With the help of the central processing unit 40, for example, the cleaning staff can be informed about cleaning tasks that have changed at short notice, which may require different surface cleaners and / or different dosages of surface cleaners. In the context of semi-automatic dosing, the user can be informed so that he can enter the correct input data, or the cleaning mixture in the mixing container 20 can be produced completely automatically so that cleaning staff with poor language skills can also perform the cleaning tasks to be performed without errors.

Finally, the cleaning trolley can also have an interface 32 via which data can be fed in from outside. For example, a position sensor 36 can also be provided on the cleaning trolley, which detects the position of the cleaning trolley in a larger object to be cleaned, such as a hospital, and which is in information exchange either with the computing unit 28 or with the interface 62. It is thus possible to communicate with a cleaning person via the interface 32 or, in the case of automatic metering, the required cleaning liquors are automatically produced. In the latter case, there would also be a storage tank with fresh water in the cleaning trolley so that a sequence of different cleaning liquors, for example with different concentrations and / or different surface cleaners, can be produced completely automatically and the cleaning staff only has to remove these automatically produced cleaning mixtures.

The following is a specific example of how to dose a surface cleaner. Surface cleaner with a proportion of nonionic surfactants of less than 5% by volume and with the chemical Composition 1-10% by volume ethanol, 1-5% by volume (2-methoxymethylethoxy) propanol, 1-5% by volume fatty alcohol polyglycol ether in water with the addition of small amounts of benzisothiazolinone and methylisothiazolinone as fragrances has a measured conductance in the undiluted state of 3.228 mS. A conductivity of 0.668 mS was determined for pure tap water. A conductance of 2.076 mS is measured at a 50% concentration. From this data it can be interpolated that at 30% the conductance would have to be around 1.45 mS. If the user wishes a concentration of 30% for the surface cleaner, a conductivity of 1.45 mS is specified as the target value and the conductivity value is continuously measured with the help of the measuring cell while the surface cleaner is being metered into the mixing vessel until this target value is reached, whereupon the Dosing is stopped either manually or automatically.

This connection is in the Fig. 2 in which the conductance of the surface cleaner (OFR) is shown in pure form and in two dilution stages. As in Fig. 2 is shown, the water quality also has an influence. Polluted water has a higher conductivity due to its higher salinity. The tap water itself also has an influence on the conductivity. so that an initial calibration of the dosing device is useful in order to improve the accuracy of the dosing.

The cleaning trolley according to the invention can be of modular construction in order to be able to perform not only simple, semi-automatic dosing tasks, but also complex tasks, which range from automatic dosing to cleaning mixtures that are automatically produced depending on the object to be cleaned. What all embodiments have in common, however, is that, due to the measurement of the conductance, the dosage is completely independent of the amount of water and that which is often found in the professional cleaning sector Overdosing some can be avoided due to ignorance or uncertainty of the cleaner.

Claims (9)

Cleaning trolley with a metering device (18) for surface cleaner, comprising: - A mixing container (20) which can be filled with any amount of water up to a maximum amount; - At least one storage container (12; 14) for surface cleaner; as - A measuring cell (24) in the mixing container (20) for determining the conductivity of the mixture; in which - A computing unit (28) is provided which compares the conductivity determined by the measuring cell (24) with a predetermined conductivity and outputs a signal when the predetermined conductivity is reached. The cleaning cart of claim 1 further comprising: - A metering element (18) for surface cleaner, preferably a metering pump for conveying the surface cleaner from the storage container (12; 14) into the mixing container (20) in order to produce a mixture of water and surface cleaner; in which - The arithmetic unit (28) terminates the energy supply to the metering element (18) when the predetermined conductance is reached. The cleaning trolley according to claim 1 or 2, further comprising a mixing device (38) in the mixing container. Cleaning trolley according to one of the preceding claims, further comprising: - An input device (30) for user-controlled input of a desired concentration of surface cleaner; and - A memory device (34) in which the conductance values of one or more surface cleaners are stored as a function of their concentration, or a calculation algorithm for determining the conductance value according to the desired concentration is stored. Cleaning trolley according to one of the preceding claims, further comprising: - A digital interface (32) to the computing unit (28) for inputting the concentration of the surface cleaner and / or the type of surface cleaner. Cleaning trolley according to claim 5,
characterized in that
the concentration of the surface cleaner can be specified as a function of the position of the cleaning trolley; wherein the current position of the cleaning trolley can be detected via a central processing unit (40) installed in the object to be cleaned. Method for dosing a surface cleaner on a cleaning trolley (10), preferably according to one of the preceding claims, comprising the steps (a) continuous measurement of the conductance of a mixture of water and surface cleaner during the addition of surface cleaner; (b) sending the measured conductance to a computing unit (28); (c) Output of a signal by the arithmetic unit (28) as soon as a conductance value specified in the arithmetic unit has been reached. The method of claim 7 further comprising, prior to step (a): - Measurement of the conductivity of the water and input of the conductivity as a reference value to the computer unit. The method according to any one of claims 7 and 8, further comprising the step:
(d) automatically stopping the operation of a metering element, preferably a metering pump, for adding surface cleaner to the mixture as soon as the signal has been output in step (c).

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