DE102005063154B4 - Dosing system for a liquid - Google Patents

Abstract

Dosing system (3) for a liquid (7), with a control unit (19) controlled mixing valve (15) via which the liquid (7) from a reservoir (12) can be metered, wherein one of the liquid (7) flows through Sensor (16) for detecting the liquid to be dosed (7) is provided, which has an upper electrode (20) and at least one lower electrode (21), wherein the electrodes (20, 21) are arranged one above the other, a distance S to each other and via the liquid flowing through (7 ') are in electrical contact and the upper electrode (20) is formed as a pipe section through which the liquid to be metered (7') flows, characterized in that the passage cross section of the upper electrode (20) is selected such that it remains filled with liquid (7 ') due to capillary forces when the mixing valve (15) is closed.

Description

Technical area

The The invention relates to a dosing system for a liquid with a control unit, wherein the dosing over the control unit has controlled mixing valve via the the liquid is metered, and a treatment unit and a method for Dosing with such a dosing.

State of the art

to Improvement of the water quality become dental treatment units with an integrated disinfection system offered. The disinfection system is usually made up of a mixing container, according to the regulation on a Air distance is separated from the drinking water network and with a predefined Water volume filled and at the same time a certain amount of disinfectant added becomes. With the thus treated water are then over a Pump supplies the respective consumers of this treatment unit. The Disinfectant is located in a housing part and will be over a valve supplied as needed to the mixing vessel. The disinfectant is usually added timed.

Except one level sensor in the reservoir, which generates only an empty message, there is no response, whether, on the fly, actually Added disinfectant has been. A faulty function of the valve can lead to despite operation no or other unintended amount of disinfectant the mixing container added becomes.

From the DD 257 115 A1 is a flow signal transmitter is known, which changes its resistance value when it is flowed through by electrically conductive liquid. The Strö determination signal generator has an upper pipe section formed as a first electrode and a second electrode disposed below, which are electrically contacted with each other. The disadvantage here is that an exact dosage is not possible that the filling state of the tube formed as a pipe top electrode is not known.

A flow switch is out of the DE 40 18 254 A1 a measuring device for flow measurement of Körberflüssigkeit is known from the DE 39 26 630 A1 known.

Of the Invention has for its object to form a dosing such and to order that a precise, correct dosage on the one hand and a feedback about the On the other hand ensured metered amount is.

Presentation of the invention

According to the invention the dosing system for a liquid one over a control unit controlled mixing valve through which the liquid from a storage container can be metered. Therefore is one of the liquid flowed through Sensor for detecting the liquid to be dispensed, which provides an upper Having electrode and at least one lower electrode. Show the electrodes at a distance S to each other, are one above the other arranged horizontally and stand over the flowing liquid in electrical contact. The upper electrode is as a pipe section formed, through which the liquid to be metered flows, wherein the passage cross-section of the electrode is selected such that this with closed mixing valve or after closing the same due to capillary forces at least partially, preferably completely filled with liquid remains. The with the liquid contact resulting change the electrical resistance between the two electrodes is recorded and so on with the dosing process for itself and the metered amount of liquid determined.

Of the electrical contact between the two electrodes is made over the flowing through Liquid by it that reaches the liquid is electrically conductive and forms a continuous liquid column. This liquid column forms So a kind of conductor between the two electrodes, causing the Resistance between the two electrodes is reduced. On the one hand Due to the capillary action, the liquid in the respective Electrode remain standing, on the other hand serves at least the lower Pipe section for catching or discharging in the open air Case between the two electrodes located liquid. The capillary action, from the surface tension of the liquid and that for dependent on the pipe section used is ensured that with sufficiently small pipe cross-section, the liquid at the lower end of the pipe section does not exit automatically. The pipe section thus remains after closing the Filling mixing valves. After opening of the mixing valve flows the liquid starting from the lower open end of the pipe section and after some time reaches the second electrode, bringing a contact is made. The leaked until then from the pipe section amount of liquid is neglected the level the liquid volume constant. The level the liquid volume has only an effect on the exit velocity of the liquid and is for the purposes of this invention are negligible.

It is only necessary to take into account the height of the fall to be overcome when determining or determining the desired volume of liquid, where against run-in times to fill the electrode, such as in the case of an empty electrode required or the emptying of the electrode need not be considered. Immediately with the opening of the mixing valve, the disinfectant flows out of the upper electrode.

Thereby the volume of the liquid to be dispensed can be sufficiently accurate be determined. Furthermore If a faulty function of the dosing system can be detected, if, despite the operation of the Valve no disinfecting liquid flows through between the two electrodes. An additional timer or one liquid sensor are not necessary.

The delivered volume of the flowing through liquid can from the cross section of the liquid column, the Exit speed and the distance S are determined.

there it is obvious that the volume of the liquid column with the height S between the two electrodes the smallest dosed and reproducible Represents volume.

It is possible, too, make the lower electrodes flat and the liquid over a to lead it from separate pipeline in which case the two electrodes are arranged in such a way that they over as the liquid jet trained conductors are connected to each other.

Furthermore the lower electrode can be a funnel-shaped inlet for metered liquid so that they the free-falling liquid jet without substantial Record losses and forward or can deliver to the mixing vessel.

From special meaning is for the present invention that the electrodes for detection the electrical resistance change via control lines can be connected to the control unit metrologically. The Control unit is used to evaluate the detected electrical Resistance values for calculating the metered volume of liquid.

In an embodiment, at least one display means provided be that information about the type and / or the amount of the done dosage gives. About the Display means can be controlled, whether by pressing the Mixing valve disinfectant was ever delivered and in which amount this was dosed. In that regard, the proper condition the for the treatment provided to the patient at the medical treatment unit Liquid, which must contain a prescribed amount of disinfectant, better controllable.

According to the invention includes a treatment unit with a filling container for dosed liquid and water a disinfectant system with a reservoir for disinfectants. The disinfectant system includes the dosing system according to the invention.

Especially at medical Treatment units is the aforementioned separation of the various Liquid container for water and disinfectants on the one hand and the use of a disinfectant on the other on the other hand prescribed, which metered added to the water must become.

at a method according to the invention for Dosing a liquid with a dosing system, the mixing valve is opened via the control unit, so that the liquid exits the upper electrode and after a predetermined fall distance S enters the arranged at a distance S lower electrode.

Advantageous It may be when the change of electrical resistance resulting from the electrical contact the two electrodes resulting from the liquid is over the Detected control unit, which differs from the flow area the electrode and the distance S resulting amount of dosed liquid be determined.

Further it is advantageous if the liquid conductivity is determined and from the type of liquid is determined. Next the type of fluid can by means of the conductance determination, if necessary, the state or the Concentration of the liquid used be rated.

Brief description of the drawing

The Dosing system according to the invention and the method according to the invention will be explained with reference to the drawing. Show it:

1 a schematic diagram of a medical treatment unit according to the invention;

2 a sectional view of the dosing system according to the invention in the first embodiment;

3 a perspective view of a dosing in the second embodiment.

embodiment

An in 1 illustrated treatment unit 1 has a disinfectant system 2 with egg ner dosing 3 as well as a mixing container 4 and a water connection 5 with a control valve 6 on. In the mixing container 4 will that be out of the water connection 5 taken water with a on the disinfectant system 3 dosed disinfectant 7 ' mixed. About a pump 8th this mixture is provided to the respective consumers, not shown.

Next to it, the mixing container 4 two level sensors 9 . 10 which report the high and low. Next to it is an overflow 11 intended.

The disinfectant system 2 points next to the dosing system 3 a preferably above arranged reservoir 12 for disinfectants 7 with a level sensor 13 and a filler neck 14 on.

The disinfectant 7 is via a mixing valve 15 to a sensor 16 and over this to the mixing container 4 issued. Both the mixing valve 15 as well as the sensor 16 are via control lines 17 . 17 ' . 18 . 18 ' with a control unit 19 electrically connected, in which also a display means 19.1 is available.

The sensor 16 has an upper electrode 20 in the form of a pipe section and a second funnel-shaped electrode arranged at a distance S below it 21 on.

Once the mixing valve 15 opens, the disinfectant flows 7 through the upper electrode 20 , emerges from this and hits after the fall S on the lower funnel-shaped electrode 21 on or passes through them. The two electrodes 20 . 21 Be that way about the disinfectant 7 in the form of a liquid column 7 ' electrically connected, so that the control unit 19 the associated change in the electrical resistance between the two electrodes 20 . 21 recorded and evaluated.

Depending on the flow cross-section of the liquid column 7 ' , which is the internal cross-section of the upper electrode 20 and the distance S between the upper and lower electrodes is the amount of dosed disinfectant 7 certainly. By repeatedly opening and closing the mixing valve 15 upon impact of the disinfectant 7 in the form of a liquid column 7 ' on the lower electrode 21 a desired amount is dispensed.

According to 2 the sensor points 16 a sensor housing 22 with a funnel-shaped inner cross-section, at the upper end of the first electrode 20 and at its lower end the second electrode 21 is provided. Both electrodes 20 . 21 are formed as a pipe section.

For contacting the electrodes 20 . 21 is the upper electrode 20 by means of a spring washer 23 to an electrical connection 24 pressed and in a similar way is the lower electrode 21 via a spring washer 25 to another electrical connection 26 pressed. The spring washers 23 . 25 are between the case 22 and one bunch each 27 . 28 the electrodes 20 . 21 arranged, the electrodes 20 . 21 in the case 22 are attached. The housing 22 itself consists of an electrically insulating material and is at the top with a plug 29 locked.

The disinfectant 7 ' flows through the upper electrode 20 and exits from this via a spout 20.1 out. Then the disinfectant drops 7 ' in free fall through the sensor housing 22 and is in the lower part by the funnel-shaped configuration of the housing 22 into the lower electrode 21 passed and steps out of this into a 1 illustrated mixing container 4 out.

The sensor housing 22 also has a ventilation opening 30 on, allowing unimpeded inflow of the disinfectant 7 in the interior between the two electrodes 20 . 21 or an unhindered exit from this guaranteed. As a result, occurring pressure differences in the interior of the sensor housing 22 balanced to the external pressure.

At the top of the electrode 20 is a hose 31 attached to the in 1 illustrated mixing valve 15 leads.

In the embodiment according to 3 is the sensor 16 as an attachment for the mixing vessel 4 educated. The first, upper electrode 20 is designed as a pipe section and protrudes through the plug 29 therethrough. At the top of the electrode 20 is the hose shown only schematically 31 attached. For electrical contacting of the electrode 20 is also in the stopper 29 fixed electrical connection 24 provided, via the only schematically illustrated line 18 with the in 1 represented control 19 connected is.

Also the second, lower electrode 21 is in the stopper 29 held, but protrudes through it and is in a horizontal distance to the first electrode 20 arranged, with the two electrodes 20 . 21 are electrically isolated from each other. Below the plug 29 At first, the electrode runs approximately parallel to the direction of fall of the first electrode 20 escaping disinfectant 7 ' and then protrudes by means of an angled section 21.1 under the first electrode 20 , The from the first electrode 20 at the outlet 20.1 escaping disinfectants 7 ' then hits after the fall distance S on the angled section 21.1 on, which causes a change in the electrical conductivity. This change is via the line shown only schematically 18 ' from the in 1 represented control 19 evaluable by the over the disinfectant 7 in the form of a liquid column 7 ' formed electrical contact and the associated change in resistance between the two electrodes 20 . 21 is detected.

So the disinfectant 7 ' from the angled section 21.1 expires, is at the end of the electrode, a downwardly directed drain 21.2 intended.

The operation of the dosing system will be described in more detail below. About the control unit 19 ( 1 ) becomes the mixing valve 15 opened and gives the disinfectant 7 free. This flows out of the reservoir 12 through the sensor 16 in the mixing container 4 , The sensor 16 consists of two electrodes 20 and 21 , which are separated by an air gap of length S from each other. The disinfectant 7 flows over the electrode 20 and falls in the form of a liquid column 7 ' on the electrode 21 , About the control unit 19 becomes the electrical connection between the first electrode 20 and the second electrode 21 registered in the form of an electrical resistance change. Immediately after detecting the disinfectant 7 becomes the mixing valve 15 closed and the liquid column 7 ' tears at the exit of the first electrode 20 from. The flow cross section between the mixing valve 15 and the first electrode 20 is suitably chosen so that the disinfectant 7 remains in the resting state by the capillary action and does not leak.

About the distance S between the first electrode 20 and the second electrode 21 and the flow diameter of the first electrode 20 or its outlet nozzle 20.1 defines a volume of liquid or disinfectant volume, the water in the mixing container 4 will be added. The distance S is determined so that there is a liquid column 7 ' training, which is not interrupted.

Depending on the switching speed of the mixing valve 15 can with immediate shutdown regardless of the level of the reservoir 12 , that is without consideration of the possibly existing gravity pressure difference of the liquid 7 in the storage container 12 , a fixed volume of disinfectant is dispensed and detected. By opening and closing several times, a larger amount can be dispensed.

Should the mixing valve 15 have an unintentional leakage flow in the locked state, so the sensor 16 at an amount that forms a continuous column of liquid 7 ' leads, also detect this leakage flow.

In addition, the type of disinfectant can be determined by determining the liquid conductivity 7 be detected.

Essential for the function of the sensor is the free air gap between the two electrodes 20 and 21 ie the two electrodes 20 and 21 must be geometrically separated from each other so that no wetted wall can build between them, resulting in a Fehlmessung or -kontaktierung by the disinfectant 7 can lead.

1

treatment unit

2

Disinfectant system

3

dosing

4

mixing tank

5

mains water supply

6

control valve

7

Liquid, disinfectant

7 '

Liquid column, dosed liquid

8th

pump

9

level sensor

10

level sensor

11

overflow

12

reservoir

13

level sensor

14

filler pipe

15

mixing valve

16

sensor

17

control line

17 '

control line

18

control line

18 '

control line

19

control unit

19.1

display means

20

electrode

20.1

outlet connection

21

Electrode, impedance probe

21.1

Area

21.2

Abtropfmasse

22

sensor housing

23

spring washer

24

electrical connection

25

spring washer

26

electrical connection

27

Federation

28

Federation

29

Plug

30

vent

31

tube

32

casing

S

fall distance the liquid, distance

Claims (11)

Dosing system ( 3 ) for a liquid ( 7 ), with a via a control unit ( 19 ) controlled mixing valve ( 15 ), over which the liquid ( 7 ) from a storage container ( 12 ) is metered, wherein one of the liquid ( 7 ) flowed through sensor ( 16 ) for detecting the liquid to be metered ( 7 ), which has an upper electrode ( 20 ) and at least one lower electrode ( 21 ), wherein the electrodes ( 20 . 21 ) are arranged one above the other, have a distance S from one another and via the liquid flowing through ( 7 ' ) are in electrical contact and the upper electrode ( 20 ) is formed as a pipe section through which the liquid to be metered ( 7 ' ) flows, characterized in that the passage cross section of the upper electrode ( 20 ) is selected such that it with closed mixing valve ( 15 ) due to capillary forces with liquid ( 7 ' ) remains filled. Dosing system ( 3 ) according to claim 1, characterized in that the sensor ( 16 ) due to the liquid to be metered ( 7 ' ) detected changed electrical resistance. Dosing system ( 3 ) according to claim 1 or 2, characterized in that the lower electrode ( 21 ) is flat. Dosing system ( 3 ) according to one of claims 1, 2 or 3, characterized in that the lower electrode ( 21 ) a funnel-shaped inlet opening for the metered liquid ( 7 ' ) having. Dosing system ( 3 ) according to one of claims 1 to 4, characterized in that the electrodes ( 20 . 21 ) for the purpose of detecting the change in resistance via control lines ( 17 ' . 18 ) with the control unit ( 19 ) are metrologically connected. Dosing system ( 3 ) according to one of claims 1 to 5, characterized in that at least one display means ( 19.1 ), which provides information about the type and / or the amount of the done dosage. Treatment unit ( 1 ) with a fillable mixing container ( 4 ) for dosed liquid ( 7 ' ) and water comprising a disinfectant system ( 2 ) with a storage container ( 12 ) for disinfectants ( 7 ), which is a dosing system ( 3 ) according to any one of claims 1 to 4. Method for dosing a liquid ( 7 ) with a dosing system ( 3 ) according to one of claims 1 to 6, characterized by the following method steps: a) the mixing valve ( 15 ) is transmitted via the control unit ( 19 ), so that the liquid ( 7 ' ) from the upper electrode ( 20 ) and after a predetermined fall distance S with a lower electrode ( 21 ) comes into contact; b) with the reaching of the lower electrode ( 21 ) the mixing valve ( 15 ) via the control unit ( 19 ) closed. Method according to claim 8, characterized in that that steps a) and b) are repeated until the desired amount of liquid is delivered. Method according to claim 8 or 9, characterized in that the liquid conductivity is determined and from this the type of liquid ( 7 ) is determined. Method according to Claim 8 or 9, characterized in that the change in the electrical resistance resulting from the electrical contacting of the two electrodes ( 20 . 21 ) through the liquid ( 7 ' ), via the control unit ( 19 ) is detected.