EP0299234A2 - Device for filling and dosing liquids in casks - Google Patents

Abstract

The invention relates to a device for the controlled metering of flowable media which reduces a subsequent dripping of the filling material to a minimum while reducing cross-sectional contractions in the piping and conveying system. The device includes a container having a constantly maintained level of the filling material, in which is arranged a bearing- and sealing-free centrifugal pump 14 which has a stopping device for the counter-current braking of its drive motor 11. The centrifugal pump feeds a rising tube having a discharge elbow 17 which has a quadratic cross-section at its entry part which merges into an outlet cross-section having the approximate shape of an isosceles triangle placed on its vertex. <IMAGE>

Description

The invention relates to a device for the flow-controlled dosing of various types of flowable media in the viscosity range below 500 mPa.s with the aid of a pump drive. It can be used for filling solutions, dispersions, emulsions, e.g. in the food industry and in chemistry, especially for paints.

It is known to generate the conveying flow of the filling material by means of pumps which displace volumes in cycles. These are positive displacement, piston or diaphragm pumps. Accordingly, volume-controlled metering is carried out by means of the same.

With these or other pumps and also by means of level control, the amount of the filling material in the container is dosed via a level control. The characteristic volume control is thus device-oriented, the one referred to as level control is used in a container-oriented manner. Filling for profit -Roberts, T.P.-Modern Paint and Coatings-New York 71 (1981) 5., Pp. 58-60.

The filling machines of the manufacturer De Vree (Belgium), which is very well known in the paint sector, also work on the basis of the positive displacement piston filling machine principle. By appointment to the paint industry filling machines by "De Vree" -Polym. Paint Col. J.-Reelhill 173 (1983) 4091, pp. 177-178.

Certain piston filling machines from "De Vree" have a pneumatic drive. With this dosing technology, the required energy expenditure is considerable. This disadvantage is exacerbated if considerable friction has to be overcome when conveying non-lubricating media for filling.

Displacer filling machines work with inlet and outlet valves (suction and pressure valves). The outlet valve is usually located in a filler neck that directs the fill jet. When the valve closes, there is regularly a larger, undefinable product residue in the dead space between the valve seat and the outlet end, which contaminates the filling station and the containers by dripping and spilling, and also causes a loss of product.

As far as remedial measures are known, all of them basically result in a fixation of the product residue between the filling operations in the nozzle by means of an additional cross-sectional constriction. Pressing the filling material through the same means a further considerable expenditure of energy.

In the case of piston filling machines, the dosing accuracy quickly decreases significantly as a result of valve and piston cylinder wall wear. The liquid filling material escapes unnecessarily at certain points, contaminates the machine and also causes a loss of the filling material.

In order to compensate for these dosing inaccuracies, the piston filling machine has not defined the quantity of product by the stroke volume, and instead a "level filling" with ultrasonic level measurement in the container and switching of the signal "filling" upon reaching the filling mark on an outlet valve mechanism has been introduced. Controlli ultrasourici accrescoulo le precisione velle operationioni de riempimento (ultrasonic controls increase the accuracy of filling processes) -Euaneler, B.-Pitture e Vernici, Milano (1986) 12., pp. 44-46.

It must be summarized that in all cases the cross-section of the filling line has to be brought to the value zero in order to stop the filling flow and metering intervals are forced onto the conveying flow of the filling material by valve actuations.

However, valves represent obstacles in the flow of the filling material, the passage of which requires additional energy expenditure and where machine wear begins in principle.

The associated effects can be considerable, and mastering the difficulties of pump wear due to abrasive media presents the designer with special technical problems. Handling manageable at high pressure, G. Vetter-Chemische Rundschau-Düsseldorf 109 (1986), pp. 944-950.

The object of the invention is to provide a device for filling and dosing liquids by means of a pump drive, which doses flow-controlled, generates the flow with less energy consumption and reduces the frictional resistance, thereby reducing cross-sectional constrictions in the line and conveyor system and dripping at the product outlet on Minimum should be reduced.

The object is achieved in that a centrifugal pump is arranged in the filling material in an automatically level-controlled filling material container, which is fed from a reserve, on the pressure side of which ascending fill pipe connects with a bend of approx. 180 ° running in the summit of the same and a shorter, shorter outlet spout, which has the same cross-section throughout. The centrifugal pump is freely accessible from the suction side. The impeller is not supported on the pump side, without a seal and connected to the drive motor with a relatively short shaft. The impeller and shaft can be easily removed.

The constant level of the filling material in the filling container is carried out with different methods, which can be selected per se, with the same characteristics as the dosing of the filling material into the container, so that the level is constantly maintained during the filling operation.

This constant level of product in the product container, which includes the suction and pressure side and is also present in the ascending filling tube, is the prerequisite for ensuring that each filling process is given a special consistency by starting from the same starting level of the product level in the filling tube, and this is ensured by a constantly sufficient supply of filling material on the suction side, i.e. a constant flow, is still supported.

The automatic level maintenance of the filling material in the filling container takes place in that a continuously charged overflow container is arranged in the same as an intermediate container, into which the centrifugal pump is immersed and from which the rising filling pipe starts on the pressure side.

The energy to be used by the filling material metering pump (centrifugal pump) up to the head from which the filling jet flows freely into the container is relatively low. The dosing process can be started without delay. To achieve the filling end, however, the drive motor is required not just to turn it off, but to stop it artificially. This is done by a stop circuit integrated in the sequence control.

This is switched so that a contactor that is switched on activates a neutral relay via a make contact, which in turn switches on a brake contactor via a make contact. This ensures that the three-phase voltage reversed in two phases is applied to the brake contactor compared to the conveyor drive, which is immediately effective as the braking current of the conveyor drive motor when the operating contactor is switched off due to the programmed filling end of the filling device.

The shutdown of the service contactor results in the shutdown of the neutral relay and this process in turn results in the shutdown of the brake contactor, which separates the phase-inverted voltage for braking from the drive motor. The motor is then no longer braked. Due to the switching inertia of the neutral relay and the downstream brake contactor in the millisecond range between the switching off of the service contactor and that of the brake contactor, there is surprisingly a reduction in the speed of three-phase motors with an output of up to 250 watts and a realizable speed of maximum 1400 min⁻¹ in the flow-ineffective Sufficient braking time range causes, that is, a phase-reversed braking current passed for a sufficiently long time without the drive motor noticeably starting again in the opposite direction.

It has been found that the solution according to the invention in the class of lower-power three-phase motors characterized above, in addition to its actual switch-off function, results in a time delay in switching off the braking current, including a timer, in the millisecond range.

When the filling jet is stopped, the entire contiguous liquid column in the filling tube automatically falls back to the level of the filling material container due to the suction lifter effect acting in this direction. This minimizes the risk of the product dripping out of the outlet end because there is no larger liquid residue in the outlet end.

To prevent dripping, an outlet elbow is designed so that the cross section of the pressure line is square. The manifold adjoins this in such a way that the boundary surface of the inner curve thereof tapers from the amount of one side of the square inlet cross-section to the amount zero at the end of the manifold, that is, when developed, there is an approximately isosceles triangle. The boundary surface of the outer arch of the same ends, likewise starting from the square side length of the inlet cross section, at the end of the elbow with a side edge of approximately twice the amount, that is to say developed as a trapezoid. The inner and outer boundary surfaces are connected with a smooth or slightly rounded section, with the manifold widening somewhat in cross-section towards its end.

The substantial last section of the outer boundary surface of the elbow is guided in an arc, the radius of which is smaller than that of the arc of the inner boundary surface, and ends earlier than the lower elbow end, with respect to the perpendicular through the end point of the inner boundary surface.

The arc of curvature of the outer boundary surface has a peak followed by a downward slope, the tangent being an angle through the end point thereof from 50 ° to 45 ° with the horizontal. The curve of the inner boundary surface, on the other hand, rises steadily until the end.

The manifold end delimited by the outer, inner and one abstracted lateral surface represents the filling mouth from which the liquid filling material is dispensed by the filling system. It has the shape of an approximately isosceles triangle placed on its tip, which forms an angle of 1 ° to 10 ° with the vertical from the lower end of its edge.

• 1. In den Füllpausen haften gebliebene, herabrinnende flüssige Füllgutreste tropfen nicht aus der Füll­mündung heraus, sondern werden von der unteren, vor­stehenden, nach innen abwärts geneigten Bodenfläche aufgefangen und in die Abfülleitung zurückgeführt.
• 2. Die entlang der gekrümmten äußeren Begrenzungsfläche geförderten flüssigen Füllgutströme werden mittels des dorthin verlagerten größeren Querschnitts der Druck­leitung durch Verzögerung beruhigt.
• 3. Die geförderten flüssigen Füllgutströme werden zusätz­lich durch den bis zur Füllmündung allmählich zunehmen­den Gesamtquerschnitt der Druckleitung beruhigt, ver­gleichbar der an sich bekannten Wirkung von Diffusoren.
• 4. Der Strahl des flüssigen Füllgutes, der von einer um 91° bis 100° gegenüber der Senkrechten rückwärts ge­neigten Austrittsöffnung in die waagerechten Öffnungen der zu befüllenden Gebinde abgegeben wird, läßt sich definiert in die verschieden weiten Öffnungen der Ge­ binde richten ohne zu spritzen, zusammenzufallen u.ä.

The following effects are achieved with this constructive measure:

• 1. Liquid filling residues stuck in the filling pauses do not drip out of the filling mouth, but are caught by the lower, protruding, inwardly inclined bottom surface and returned to the filling line.
• 2. The liquid filling material flows conveyed along the curved outer boundary surface are calmed by delay by means of the larger cross-section of the pressure line which is moved there.
• 3. The conveyed liquid filling material flows are additionally calmed by the overall cross-section of the pressure line, which gradually increases up to the filling mouth, comparable to the known effect of diffusers.
• 4. The jet of the liquid filling material, which is emitted from an outlet opening that is inclined backwards by 91 ° to 100 ° with respect to the vertical, into the horizontal openings of the containers to be filled, can be defined in the openings of the Ge having different widths straighten bandage without splashing, collapsing, etc.

With the device according to the invention, all types of relatively wide open containers such as cans, hobbocks, jugs, etc. can be filled.

The invention is explained in more detail below using an exemplary embodiment.

• Fig. 1: die Dosier- und Abfülleinrichtung in einer axonometrischen Darstellung;
• Fig. 2 und 3: die Steuerung, die beispielsweise aus elektrischen oder aus pneumatischen Schalt­elementen aufgebaut werden kann;
• Fig. 4 und 5: die Stoppschaltung des Pumpenantriebes;
• Fig. 6: den Auslaufkrümmer in einer Vorderansicht;
• Fig. 6a: den Krümmer nach Fig. 6 in einer Seiten­ansicht;
• Fig. 6b: den Krümmer nach Fig. 6 in einer Drauf­sicht.

In the accompanying drawing:

• 1: the dosing and filling device in an axonometric representation;
• 2 and 3: the control, which can be constructed, for example, from electrical or pneumatic switching elements;
• 4 and 5: the stop circuit of the pump drive;
• 6: the outlet elbow in a front view;
• 6a: the manifold of Figure 6 in a side view.
• Fig. 6b: the manifold of Fig. 6 in a plan view.

If, according to FIGS. 1 and 2, an energy supply 7 is activated, auxiliary energy is provided for the control and message 9, a container conveyor 13 transports a container 18 to the effective area of a container detection 15. When the sensor for container detection 1 has detected the container 18, Via a path switch 2 and an amplifier 5, a drive 6 of the container conveyor 13 stopped so that the container 18 under an outlet manifold 17 comes to a standstill.

The coasting time of the drive of the container conveyor 6 is shorter than the time it takes a centrifugal pump 14 to lift the filling material from the level in the filling material container 16 to the level of the discharge elbow 17, so that the filling of a container 18 always begins after it has stopped .

Simultaneously with the start of a centrifugal pump drive 11, a filling quantity program 3 is started.

For this purpose, a start command 25 switches on a service contactor 21 via a programmed runtime control 26, and a three-phase motor 24, which has a power of up to a maximum of 250 watts and a maximum speed of 1400 rpm, starts up (filling process). A neutral relay 28 is activated via a make contact 27 of the operational contactor 21, which switches on a brake contactor 20 via a make contact 29 and thus prepares for braking.

The programmed filling termination switches off the operational contactor 21 and its power contacts 23 switch to the open position. If the neutral relay 28 and the brake contactor 20 switch off with a delay of one millisecond, depending on the type, with respect to the operating contactor 21 connected upstream of them, i.e. are still briefly activated for switching the braking current, the main current paths for such a current are turned in the opposite direction via a contact set 22 of the still activated brake contactor 20 and the contact set 23 of the already falling contactor 21 closed, whereby the braking is effected by countercurrent. The relays 28 and brake contactor 20, which drop sequentially in the millisecond range, finally disconnect the motor from the mains again.

A further rotation of the motor in the conveying direction or in the opposite direction up to a speed that would cause the flow rate of the metering pump can thus be reliably prevented.

After the filling quantity has been reached, the centrifugal pump drive 11 is stopped by a filling quantity program 3 via the amplifier 10. The period of time required for the liquid cross-section to be torn off from the outlet elbow 17 is programmed in the start-up delay of the container conveyor 4.

After this time program has expired, the amplifier 5 starts the drive of the container conveyor 6 and transports the filled container 18 out of the effective range of the sensor 1. This resets all switching functions.

When a container 18 is recognized again on sensor 1, the program described is executed again.

The outlet elbow 17 prevents dripping. It is designed in such a way that the cross section of an inlet part 30 is selected to be square, while its outlet cross section 33 is triangular approximately isosceles. The outlet pipe end piece, which is curved, acts as a diffuser.

The curvature of a top surface 31 takes place shortly before the apex, the radius R 1, and then merges into the radius R 2. The ratio of the radii R 1: R 2 is approximately 4.

At the end point of the top surface 31, a tangent forms an angle of 50 ° to 45 ° with the horizontal. The development of the top surface 31 is a trapezoid, the Parallels are formed from one side of the square entry part 30 and an edge 34 of the top surface 31. The length ratio between one side of the inlet part 30 and the edge 34 of the top surface 31 is approximately 0.6. The development of the arcs R 1 and R 2 forms the length of the axis of symmetry of the trapezoid.

The bottom surface 32 follows the radius R 3, the length resulting from the ratio R 3: R 1 approx. 0.5.

At the beginning of the outlet pipe end piece, the circularly curved bottom surface 32 rises vertically and ends approximately 3 to 5 mm before reaching a horizontal course, so that the bottom surface 32 is always inclined in the direction of the riser pipe.

The development of the bottom surface 32 is approximately an isosceles triangle, the base line of which is equal to one side of the entry part 30 and the height of which is the development of the circular arc with the radius R 3.

In this way, an outlet cross section is formed from the approximate shape of an isosceles triangle, which stands on the tip and forms an angle of 91 ° to 100 ° with the plane of the filling opening of the container 18 to be filled.

The two side surfaces 35 of the outlet line end piece are formed by abstract connection of the described top surface 31 and bottom surface 32. The side surfaces formed in this way can also be rounded on the outside. Bottom, top and side surfaces enclose the cross sections which increase towards the filling mouth, which leads to the above-mentioned diffuser effect.

This configuration further causes the velocity profile shift due to the curvature to be compensated for with larger amounts towards the top surface and with smaller amounts towards the bottom surface by a larger cross-sectional area at the points of higher speed for the purpose of deceleration and reduction in cross-section at points of lower speed for the purpose of acceleration , so that a smooth outflow jet, which falls freely under the influence of the filling mouth design and gravity in the direction of the container opening and breaks off immediately when the flow drive is stopped.

As a result, filling material still adhering to the inner walls runs together and then in the direction of the bottom surface 32 and is returned to the inlet part 30.

The pressure line described with a specially designed elbow as a filling line end piece is used, for example, in a filling system controlled by a flow.

List of the reference numerals used

• 1 sensor for container detection
• 2 way switching
• 3 Fill program
• 4 Start-up delay of the container conveyor
• 5 amplifier drive of the container conveyor
• 6 Drive of the container conveyor
• 7 energy supply
• 8 energy distribution
• 9 Auxiliary energy for control and reporting
• 10 amplifier centrifugal pump drive
• 11 centrifugal pump drive
• 12 hold-down devices
• 13 container conveyors
• 14 centrifugal pump
• 15 Container detection
• 16 filling containers
• 17 discharge elbows
• 18 containers
• 19 control
• 20 brake contactor
• 21 contactor
• 22 contact set
• 23 power contacts
• 24 three-phase motor
• 25 start command
• 26 Runtime control
• 27 NO contacts
• 28 neutral relay
• 29 NO contacts
• 30 entry part
• 31 top surface
• 32 floor area
• 33 outlet cross section
• 34 edge
• 35 side faces
• R 1 radius
• R 2 radius
• R 3 radius

Claims (5)

1. device for filling and dosing liquids into vessels using a pump drive,
characterized,
that a centrifugal pump (14) is immersed in a filling material container with a stop device, which has a riser pipe on the pressure side with a profiled outlet elbow (17). 2. Device according to claim 1,
characterized,
that the outlet elbow (17) of the riser pipe has a square cross-section at its inlet part (30) and the cross-section of an isosceles triangle placed on the tip at its outlet end (33), the cross-sectional change taking place gradually and with a constant flow cross-section. 3. Device according to claim 1 or 2,
characterized,
that
the bottom surface (32) of the outlet elbow (17) tapers in the course of the inner curve from the amount of one side length of the inlet cross section to the amount 0,
- The bottom surface (32) increases steadily without reaching the summit of the curvature to the outlet.
- The bottom surface (32), based on the direction of the outlet, in the side view of the same deviating by 1 ° to 10 ° from the plumb line, further advanced than an edge (34) of the top surface (31) ends.
a top surface (31) of the same extends in the course of the outer curve from the amount of one side length of the square inlet cross section to approximately twice the amount at the top edge length of the outlet,
- The curvature of the top surface (31), starting shortly before the summit of the curvature, has a smaller radius than the curvature of the bottom surface (32) and runs downwards with a tangential inclination of 50 ° to 45 ° to the horizontal. 4. Device according to one of claims 1 to 3,
characterized,
that the stop device of the bearing and sealless centrifugal pump (14) has switching means for countercurrent braking of its drive motor (11). 5. Device according to claim 1 to 4,
characterized,
that a contactor (21), which is switched on, activates a neutral relay (28) via a make contact (27), which in turn turns on a make contactor (20) via a make contact (29), to which a phase-reversed three-phase voltage for countercurrent braking is applied acts as the braking current of the drive motor when the service contactor (21) is switched off and lasts as long as the type-specific switching inertia of the neutral relay (28) and the brake contactor (20).

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