EP3028777B1 - Mixing device with connector for simultaneous internal and external cleaning - Google Patents

Description

The invention relates to a mixing unit for producing ready-to-use rinsing solutions for medical purposes according to the preamble of patent claim 1.

The aim of this development is the cost-effective preparation, storage and mobile administration of irrigation solutions by using Purisole, Ringer, saline, and concentrates that are mixed with a locally prepared, chemically and microbiologically highly pure liquid into a ready-to-use irrigation solution for surgical operations, e.g. Gynecology, urology, arthroscopy can be mixed.

A mobile liquid storage device that is equipped with a sterile disposable item, an exact volume determination and a sterile removal make it easy and inexpensive to use and administer.

An application of this development for other areas such as for general surgery, veterinary medicine, in the laboratory or in biology and in pharmacy as a high-purity rinsing liquid or preparation medium for the production of medication, cell cultures and the like is conceivable and practical. Medical rinsing solutions are usually processed from distilled water as the basic material, which is produced centrally, processed into rinsing solutions in a central production process and brought to the application site with considerable logistics costs.

The US 2005/0171501 A1 discloses a mixing unit according to the preamble of claim 1, with a mixing chamber and lines opening therein for high-purity water and for concentrate to be ready for use in the mixing chamber To form rinsing solutions, with a concentrate bag, which is provided with a concentrate bag connection connector, and with a connection connector of the mixing chamber, which can be connected to the concentrate bag connection connector.

A similar state of the art is in the DE 4 121 568 A1 disclosed.

The EP 2 142 316 B1 discloses a chamber for washing the pouring out of a milk storage and cooling container. The milk container is provided with a drain pipe, to which a hose can be connected to pump milk. A fixed element is permanently mounted on the nozzle, which forms a wash cabinet together with a movable element in the form of a bowl. The rinsing liquid comes out of the nozzle. In addition, a vent tap is connected to the wash cabinet.

The mixing unit according to the invention according to claim 1 has a mixing chamber and lines leading into it for high-purity water and for concentrate in order to form the ready-to-use rinsing solution in the mixing chamber, furthermore with a concentrate bag into which the concentrate can be filled and which has a concentrate-bag connection connector is provided, and is provided with a connection connector of the mixing chamber which can be connected to the concentrate bag connection connector, the connection connector of the mixing chamber being connected to a pivotable concentrate flap which, in its closed state, covers the connection connector in such a way that a tight washing space is formed around the connection connector is, and wherein the mixing unit has a flushing line, which is provided with a pump and a flushing valve and opens into a rear annular gap of the connection connector, with peripheral flushing holes leading from there into the flushing chamber, so that when running the pump the connector inside and outside is completely cleanable

For medical use, for example, industrially manufactured flushing solutions with a volume of 3l, 5l, 10l are made available to the hospital. disposed of.

For the duration of the operation or examination, these bag volumes, for example for a bladder operation with approx. 60 l of rinsing liquid, are not sufficient, so that a jumper must be available outside the central operating area in order to prepare, warm up and hand in the bags.

The administration is partly gravimetric or with bag pressure cuffs. In addition, expensive disposable items such as pump segments or the bag warmer are often required.

A significant disadvantage e.g. in endoscopic examinations there is a lack of visibility due to floating tissue or pulsating rinsing liquid because, for example, the required rinsing liquid pressure is not kept constant between 0.1 bar and 0.3 bar.

Rinse generously to improve wound hygiene. This causes personnel and material costs.

The regulatory and normative requirements for the quality of water as a raw material are so high that it has not been possible to date, e.g. in the hospital to produce verifiable medical irrigation solutions on demand. On the one hand, there are the high microbiological and, on the other hand, the required chemical requirements for the raw material water, which stand in the way of a verifiable and verifiable normatively required quality of the locally controlled production.

The decentralized production of medical irrigation solutions by hospital staff requires safe processes in terms of both operation and the reliability of the technology with regard to the irrigation solution quality.

Necessary improvements, purpose and aim of this invention are therefore the cost-effective, user-friendly on-site manufacture of a flushing solution with little personnel and a flushing volume corresponding to the examination or also to several operations.

Storage, long-term stability and the lowest possible volume of the concentrates are of particular importance. Further requirements are the uninterrupted administration without additional personnel expenditure while maintaining the application temperature and hygiene of the solution.

A space-saving technology for the production of the rinsing solution and a mobile rinsing solution container are to be used, which contain the essential components for high hygiene, safety, simple operation and a constant flow and pressure for the administration of the rinsing liquid.

Residual quantities should be easy to dispose of.

A high availability of the devices for all measurement and monitoring tasks with regard to their intrinsic safety and only a remote probability of failure is important in order to avoid a catastrophic impact for the patient under all circumstances, or the quality or toxicity of the liquid produced is flawless in the assured acceptance criteria to monitor.

This object is effectively achieved in that the combination of a reverse osmosis membrane and two further filter stages, for example ultra or sterile filters, preferably as a capillary membrane, are used to produce the rinsing solution.

This filter combination and other components are referred to below as the filling station.

For the preparation of, for example, approx. 60 l of ready-to-use purisol solution, approx. 56 l of sterile-filtered permeate must be diluted or mixed proportionally with approx. 3.6 l of highly concentrated purisole concentrate so that the rinsing solution formed can be used without further tests for intra- and postoperative bladder irrigation.

A formulation in the final dilution of 27.0 g sorbitol and 5.4 g mannitol per liter of highly pure liquid is required for purisol concentrates. In practice, a tolerance range of 25.65 - 28.35 g for sorbitol and 5.13 - 5.67 g for mannitol plus approximately 1 liter of liquid is acceptable.

Through trials and tests, the sorbitol concentration for a concentrate volume of 1 l was approx. 443.6 g, the mannitol concentration was approx. 88.7 g with a liquid quantity of approx. 648.7 g to a concentration factor of approx. 16.43 and one Density increased by approx.1.1806 g / cm ³ (20 ° C).

A concentrate volume of approx. 3.652 l + 56.38 l high-purity liquid results in approx. 60 l finished purisol rinsing solution. This concentrate then contains approx. 1620 g sorbitol, approx. 324 g mannitol and approx. 2369 g liquid.

The solubility of the substances in the manufacture of the concentrate and a permanent solution thereof without precipitation at low temperatures e.g. at 5 ° C the concentration factor of approx. 16-17 times suggests by examinations.

The above rinsing solution is representative e.g. for Ringer's and / or other sodium chloride solutions, which can be used in particular in the field of surgery, but also in other medical or named areas. The concentrates and their mixing ratios have to be adapted to the respective applications.

Frequently used as a rinsing solution e.g. 0.9% sodium chloride solutions. With a ratio of 1:35, a concentrate volume of approx. 2.9 I is sufficient to prepare approx. 100 l of this solution.

Wrestler flushing solutions are to be produced with slight deviations from the above. For example, with a mixing ratio of 1: 34.6 and approx. 2.872 l wrestling concentrate, 100 l wrestling solution must be prepared.

The concentration to approx. 30-35 times, at a solubility temperature of approx. 10 ° C shows the potential of logistics, handling and space savings.

However, the described method and the components and volumes used are not limited to this. Due to the high-purity active ingredients, the exact mixing and dilution, a wide range of rinsing solutions can be produced.

Advantageously, due to the high concentration, the germ growth of the concentrate is almost prevented.

To prepare the rinsing solution, the concentrate container, which is designed as a bag, is hung on the prepared receptacles of the filling station concentrate scales and the mixing process is initiated. The scale is first verified by the known bag weight.

The filling station-side connections of the concentrate as well as the rinsing solution bag to be described are made by the user to self-cleaning, confusion-proof connection connectors of the filling station, which in this application are designed, for example, as flap solutions, but can also be designed as flexible hose lines on the device side.

A mobile flushing solution container, which is preferably designed as a pressure container, is fitted with great advantage with an insertable sterile flushing liquid bag which is filled with a correspondingly large volume.

The flushing solution bag contains an inseparable connection connector that can be inserted and fixed through the lockable lid of the pressure vessel. The connection connector can be provided with further flexible hose lines which are designed as filling or transfer lines. The connector can advantageously also be designed as a hose that can be used either as a filling hose or as a transfer hose depending on the sterility requirements.

For the administration of the rinsing liquid at the application site, a transfer system, for example with an endoscopy system, can be connected to the transfer connection of the rinsing solution connector. A connection to other systems common in surgery, for example to irrigation suction systems, is also practical and possible.

The task of simple operation and administration with a constant flushing flow and pressure was solved by introducing compressed gas (air) either preferably into the pressure container or optionally directly into the flushing liquid bag.

The pressure gas control and monitoring are advantageously set up within the mobile flushing solution container. Compressed gas generation and feed can be generated, for example, by an in-house source, but also on the device side.

The proportioning of concentrate and permeate is carried out by means of a concentrate and a rinsing solution container scale, the concentrate scale being verified in the filling station each time the filled concentrate container is attached.

For this purpose, the mobile rinsing solution container also advantageously includes a scale that monitors the filling level and which is to be tested automatically for safety reasons using the reference weight.

For homogenization and temperature control, highly pure or almost sterile permeate is heated and mixed with the added concentrate in a mixing block.

A second sterile filtration of the mixed solution was carried out before introduction into a sterile rinsing solution container / bag.

The cleaning of the system or germ prevention and reduction are achieved by the combination of a slightly toxic, citrate-based disinfection and Detergent running with water heating. Whereby both the primary and the secondary side of the reverse osmosis are separated from each other by means of a additional pump must also be disinfected or cleaned without transmembrane flow.

In principle, all process-relevant data are recorded by both the operating and the protection computer and, if necessary, calculated. The measurement results are sent from the operating computer to the protection computer and vice versa. Each computer compares the measurement results with its own and returns an acknowledgment.

After confirmation of the operating and protection computers, the data are written to the trend data memory together with a checksum, which can preferably be designed as an Eprom, but also as another storage medium.

The electronics of the mobile rinsing solution container can be operated by means of rechargeable batteries. The display of the mobile rinsing solution container shows all necessary parameters as well as their deviations such as weight, temperature and container pressure.

By establishing a wireless data exchange between the filling station and the mobile flushing solution container, the filling, the proportionality and the temperature are monitored, for example.

Further details and advantages are described in the figures shown below.

Figure 1 shows the entire preparation up to the application. The liquid to be processed can be passed on to the RO system (2), for example, via an optional prefiltration (1), which can be designed as particle and or further filter stages to eliminate hardness formers and chlorine.

In order to eliminate microbiological contamination, the RO (2) contains, for example, a disinfection unit (4) with which chemothermal disinfection can be carried out without the user having to do anything. Canister (67) contains the disinfectant / cleaning agent which is advantageously used as a citrate-containing solution. The further function of device (4) is derived from the representation and is not further described here. Of course, there is the possibility of hot cleaning the RO system without the use of further disinfectants.

The permeate generated by the RO system (2) is circulated over the primary side of the filter (3). The permeate released by the RO controller (58) by means of a conductivity measurement (not shown) reaches the secondary side of the filter (3) and via permeate release valve (5) to the mixing unit (12).

Permeate that has already been preheated by the RO system (2) is heated to the required rinsing solution temperature by means of a heater (9) and temperature controller (8,13). The permeate is fed to a mixing chamber (15) via line (11), into which concentrate from bag (26) and line (25), the connector (24) and the device-side connection connector (22) is fed by means of a pump (23).

The concentrate flap (20) is open, detector (19) reports "open" because magnet (21) has exceeded the required distance. The concentrate flush valve (17) is only opened when the flap (20) is closed and the flushing programs selected or preset accordingly in order to clean the connection connector (22).

Concentrate bag (26) is suspended with its suspensions (27) in corresponding hooks on the concentrate bag scale (28). The known bag weight is used for verifying the scales.

The second conductivity and temperature measurement (16) detects the corresponding values for reasons of redundancy. The flushing liquid homogeneously mixed and tempered by chamber (15) reaches a second sterile filter (30) via line (29). Faulty rinsing liquid is discarded to the drain (100) via the bypass valve (31).

When the valve (31) is closed and the rinsing solution release valve (33) is open, the rinsing liquid is conducted via the rinsing solution connector (35) on the device side, the bag connector (38), line (39) connected to it, to the mobile rinsing solution container (40), in which a sterile rinsing solution bag (82) is inserted. The possibility of taking a quantity of rinsing solution is provided by taking a sample (32).

The mobile flushing solution container contains a scale (43) which registers the respective fill level or the weight of the flushing quantity. A temperature sensor (59) is also attached so that the rinsing liquid temperature can be measured directly.

When the rinsing solution flap (36) is closed and a suitable rinsing program is selected and initiated, the device-side connector (35) is rinsed or disinfected with sterile liquid or cleaning solution via the rinsing drain (99). The filter (3/30) is tested with closed flaps (20/36) by filtered air supply by means of an air pump (6) and can optionally apply air to the secondary side of the filter (3) or the primary side of the filter (30) by valve switching. The liquid is partially displaced by the air. Due to the hydrophilic character of the filter membrane, there is only a very small pressure drop with an intact filter characteristic, which can be registered or monitored by means of pressure sensor (14) and electronics (58).

With this test, both the filters (3/30) and the tightness of the flaps (20, 36) can be verified or checked.

Likewise, in Figure 1 schematically shows a possible transfer of the rinsing liquid to an endoscopic system (57). Compressed air connector (48) can be connected to an in-house compressed gas source using flexible hose lines (49).

To ensure a constant flow of flushing liquid, the pressure control unit (47) includes an adjustable pressure regulator (50), an emergency stop with mushroom button and forced ventilation (51), a manual pressure relief valve (52), a pressure gauge display (53) and an electronic pressure sensor (54), which, like all sensors and actuators, can be evaluated and displayed using redundant electronics (58).

The low pressure control valve (50) is adjustable. The pressure control unit (47) can be designed for a control range from 0 to 0.5 bar and is set to 0.3 bar delivery pressure for practical use, for example in prostate surgery. The air regulated in this way is introduced into the pressure container (45) via a hose connection (66).

The rinsing liquid in the bag (82) is conveyed to the endoscopic system (57) by the pressure supplied via the transfer connection (55) and a suitable transfer system (56).

It goes without saying that system (56) can also be connected to units other than endoscopic systems, such as, for example, the irrigation suction systems customary in surgery.

In addition, it is found that a further sterile filter (not shown here) could be connected to line (56).

There would also be the option of introducing the regulated pressurized gas medium directly into the flushing solution bag (41) or directing the transfer via a pump with a single-use hose segment.

Figure 2 spatially illustrates the overall unit of a mixing plant or filling station. Due to the assumed space constraints in the hospital, the filling station (60) was constructed as flat as possible so as not to interfere with the passageways in corridors or rooms. This requires a vertical construction of the RO system (2) with membrane (68), flow tank (69) and pump (70). A cleaning canister (67) is also shown.

The mixing unit (12) is attached above the RO system, only the position of the concentrate flap (20), the rinsing solution flap (36) in this drawing. the heater (9) and the sterile filter (30) is pointed out to illustrate the handling. The flaps are shown here in the closed state. Concentrate bag scale (28) is mounted below the electronics (58) and is shown in the form of an extension arm (71) with a hook for the concentrate bag.

The installation is flush with the wall at a suitable location with a corresponding height distance from the floor to ensure communication - as explained later - and cleaning.

The mobile flushing solution container (40) consists of a transport carriage (46) with a pull and push handle (61), the pressure container (45), a lid (44) and an infusion rod (63).

Components of the mobile flushing solution container (40) are a pressure control unit (47), the output of which opens directly into the pressure container (45) via a flexible hose connection (66) and electronics (62) with a communication display (65), for example for displaying the fill level Temperature, compressed air and other relevant values and a traffic light (64).

Communication between the rinsing solution container (40) and the filling station (60) takes place wirelessly by means of sensors in the roller area below the base plate (104) of the transport trolley (40).

The detection of the parking or docking positions of the rinsing solution container (40) at the filling station (60) is predetermined by the position of the preferred infrared sensors.

A corresponding sensor is attached to the filling station on the same level. The docking angle and position to the filling station must be influenced by the selection and position of the sensors.

The other components are partly explained from the illustration or will be explained at a later point in time. It goes without saying that this is a space-saving construction of the components, the arrangement of which may differ from that shown or is also conceivable in other embodiments. Likewise, reference was not made to the labeling in all points.

Figure 3 shows schematically the pressure vessel (45) with open lid (44) and a connector receptacle (78) through which the cylindrical bag connector (83) is inserted, and is held by means of a movable connector lock (79) and holding groove (87).

To ensure a positive seal with good sliding properties between the connector (83) and the connector receiving seal (78), the seal (78) preferably consists of a Teflon insert (128), which is fitted with an O-ring (126) and a pressure plate (127). is pressed against connector (83) in such a way that the aforementioned goals are achieved.

A form-fitting and sealing connection of the cover (44) to the pressure vessel (45) is produced on the one hand by the cover seal (74) and the conical seal bearing (77) in the pressure vessel opening in the closed state.

To lock, hook (126) pulls the lid lock (76) into position using the locking handle (80). Locking device (81) snaps behind the swivel joint (124).

Lid clamp hinge (75) holds lid (44) in the open position in an upright position.

It goes without saying that the bag (41/82) has to be introduced into the container.

For vertical support, two lateral guides (73) are attached to the pressure vessel (45).

The compressed air supply (66) is mounted, for example, in the hinge area (75) by means of a connection (84).

In the event of a fault, the connector lock (79) can be opened from the outside using the rotary shaft (85) using a tool.

Also shown in this figure is the filling line (39) with connector (38) which is to be connected to connection (35) in the filling process. After the filling process, clamp (72) can be closed. To differentiate the filling line (39) and the transfer line (55), these are equipped with different connectors and are of different lengths, as shown.

Figure 4 schematically shows in perspective the concentrate flap (20), the opening, closing, excavation and cleaning process of which is described as follows.

There is a magnet (21) in the flap (206), which activates a magnetic contact (19) when the flap is closed.

For flushing, the flap (20) is closed, so that the flap locking hook (91) of the flap locking (89) engages in the locking collar (96) of the connection connector (22).

By pushing the locking mechanism (89) back over the pivot point (92) using the flap locking handle (90), the locking spring (93) is compressed and the flap locking hook (91) releases the lifting process of the flap (20). The flap swings up. This is supported by lifting spring (102) which engages on the side of the pivot point (101).

For complete flushing of the connector (22), the seal (94) presses positively on the outer cone (95) of the connector (22) when the flap is closed, thereby sealing the flushing chamber (103).

When the flush valve (17) is open, liquid flows via line (18) into a rear annular gap (97) of the connector (22) and from there through the circumferential side

Rinsing holes (98) to the wash cabinet (103). With the pump (23) running, the connection (22) is completely cleaned inside and out and can be freed from liquid residues after the cleaning process during the pressure maintenance test.

When the flap (20) is open, the concentrate connection (24), which is equipped, for example, as a female connector with an internal cone 1/18 and a two-start external thread 10x6, can be screwed into the concentrate bag connection connector (22) with the appropriate cones and threads. The crushing cone (112) must be broken. In the coupled state, a form-fitting, sealing connection is ensured, for example, by the inner and outer cones and the thread.

The supply of the permeate via line (11) into mixing chamber (15) and the concentrate via pump (23) is shown schematically. The mixed rinsing solution is discharged via line (29). In order to generate the corresponding homogeneity, the line feeds take place tangentially or in a suitable manner.

In order to avoid confusion for the application, the technical design of the rinsing solution connections was designed differently from that of the concentrate connections.

The shows Figure 5 schematically the concentrate bag (26) which consists of a toxicologically harmless material - preferably PE film.

The bag (26) has a rectangular, welded contour. Bag fillings of approx. 1-5 liters can cover the concentrates used in surgery and their formulations for producing the required rinsing solution.

For connection to the connector (22) on the device side, the connecting hose (25) can be of different lengths. Bag (26) is hung into the extension arm (71) with its hanging openings (109). Boom (71) has a Z-shaped bend and is attached to bending beams by means of screws (115) for reinforcement and positive connection with cutout (114). It goes without saying that at the beginning of the mixing process remove the sterile protective cap (113) and Breaking cone (112) is to be broken. Filling connection (110) is welded. The rear end of the bending beam is screwed to a support arm (106), which in turn is adjustably connected to the rear wall (41) of the filling station (60) by means of an adjusting screw (116). <B> Legend </ b> 1. Pre-filtration Second RO system Third Permeate ultra / sterile filter 4th disinfection unit 5th Permeatfreigabeventil 6th Air pressure supply, air pump 7th Intake air filters 8th. thermostat 9th Heater mixing circuit 10th Overtemperature protection 11th Permeatversorgungsleitung 12th mixing unit 13th Temperature controller / display 14th pressure sensor 15th mixing chamber 16th Redundant conductivity measurement / temperature display 17th Konzentratspülventil 18th flushing line 19th Concentrate flap detector 20th concentrate flap 21st magnet 22nd Device-side concentrate bag connection connector with double-start internal thread and internal outside cone 23rd concentrate pump 24th Concentrate bag connector with crushing cone with 2-thread and internal cone 25th Concentrate bag connection hose 26th concentrate bag 27th Suspension concentrate bags 28th Concentrate bag scales 29th rinse solution conduit 30th Sterile filter 2 31st Spüllösungsbypassventil 32nd sampling 33rd Spüllösungsfreigabeventil 34th Spüllösungsklappendetektor 35th Device-side flushing solution connector with inner cone and two-start external thread 36th Spüllösungsklappe 37th magnet 38th Rinsing solution bag connector with external cone and internal thread 39th Spüllösungsfüllleitung 40th Mobile rinsing solution container 41st Back panel filling station 42nd Cabel Canal 43rd Rinse solution scales 44th cover 45th pressure vessel 46th Dolly 47th Pressure control unit 48th Compressed air connector 49th hose extension 50th pressure regulator 51st Emergency stop switch 52nd Pressure relief valve 53rd pressure gauge 54th pressure sensor 55th Transfer connection with two-start external thread, internal cone and closure flap 56th transfer system 57th OP application 58th electronics 59th temperature sensor 60th filling station 61st Pull and push handle 62nd Electronics for dolly 63rd IV pole 64th Traffic light display 65th Communication display for pressure, temperature, level 66th Compressed air hose connection 67th Disinfectant / detergent canister 68th RO membrane 69th feed tank 70th Pump with drive 71st Concentrate scale boom with bag hook 72nd hose clamp 73rd Lateral guide pressure vessel 74th cover gasket 75th Cover Terminal Hinge 76th lid lock 77th Pressure vessel opening with conical seal bearing 78th Connector mount with internal preloaded sliding seal 79th connector locking 80th Locking handle with hook 81st locking safety 82nd Spüllösungsbeutel 83rd bag connector 84th Compressed air supply 85th Locking rotary shaft with external hexagon socket 86th ejector 87th retaining groove 88th Inner cone concentrate connector 89th lid lock 90th Fold latch handle 91st Door locking latches 92nd Door latch pivot 93rd Lid lock spring 94th flap seal 95th Sealing abutment 96th locking collar 97th Annular gap rinsing flow 98th Circumferential flushing holes 99th Spülabfluss 100th outflow One hundred and first Rotary shaft concentrate flap 102nd excavation spring 103rd Wash cabinet 104th Bottom plate of mobile flushing solution container 105th roll 106th Bracket attachment for load cell 107th Mounting block for permeate conductivity sensor 108th Heater permeate circuit 109th Einhängöffnungen 110th Filling connector 111th labeling 112th crushing cone 113th sterility cap 114th outbreak 115th screw 116th adjustment 117th Bending-beam Wäagezelle 118th 119th 120th 121st 122nd 123rd Pivot for pivot 124th swivel 125th Phase swivel 126th O-ring 127th printing plate 128th Teflon insert 129th 130th Hook locking handle

Claims (10)

1. A mixing unit (12) suitable for the production of ready-to-use flushing solutions for medical purposes including a mixing chamber (15) and conduits communicating therewith for ultrapure water and for concentrate in order to form the ready-to-use flushing solutions in the mixing chamber, further including a concentrate bag (26), which may be filled with concentrate, and which is provided with a concentrate bag connector (24), and including a connector (22) for the mixing chamber (15), which is connectable to the concentrate bag connector (24), characterised in that the connector (22) for the mixing chamber (15) is connected to a pivotable concentrate flap (20), which so covers the connector (22) in its closed state, that a sealed flushing space (103) is defined around the connector (22), and that the mixing unit (12) has a flushing conduit (18), which is provided with a pump (23) and a flushing valve (17) and communicates with a rear annular gap (97) of the connector (22), wherein peripheral flushing bores (98) lead from there into the flushing space (103) so that when the pump (23) is running the connector (22) may be thoroughly cleaned internally and externally.
2. A mixing unit as claimed in Claim 1, characterised in that the concentrate bag (26) in the mixing unit (12) is connected to a concentrate bag scales (117).
3. A mixing unit as claimed in Claim 1 or 2, characterised in that the concentrate bag (26) consists of a toxicologically harmless material, such as a PE film.
4. A mixing unit as claimed in one of Claims 1 to 3, characterised in that the concentrate bag (26) has a rectangular, welded contour and is suspended with two openings (109) in a cantilever arm (71) of the concentrate bag scales (117).
5. A mixing unit as claimed in one of Claims 1 to 4, characterised in that the concentrate bag connector (24) has an external screwthread and an internal taper and the connector (22) of the mixing unit (12) has a matching internal screwthread and external taper.
6. A mixing unit as claimed in Claims 1 to 5, characterised in that the concentrate bag connector (24) includes a rupture cone (112).
7. A mixing unit as claimed in Claims 1 to 6, characterised in that the concentrate bag (26) additionally includes a filling connector (110) for the concentrate.
8. A mixing unit as claimed in one of Claims 1 to 7, characterised in that a concentrate pump (23) is provided which supplies concentrate in accordance with the measurement values from the concentrate bag scales (117) and a flushing solution container scales (43) of the mixing chamber (15).
9. A mixing unit as claimed in one of Claims 1 to 8, characterised in that the concentrate for the ready-to-use flushing solution is Purisol concentrate, which contains 443.6g sorbitol, 88.7g mannitol and 648.7g water per litre concentrate volume.
10. A mixing unit as claimed in Claim 9, characterised in that the concentration factor of the Purisol concentrate is 16 to 17, wherein the Purisol concentrate remains without sedimentation at low temperatures of ca. 5°C.

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