EP0333910B1 - Drum-filling device with a balance and a suction extractor controllable in height - Google Patents

Description

The invention relates to a barrel filling device mentioned in the preamble of claim 1.

Drum filling devices with scales are known, for example, from the applicant's prospectuses. They allow the precise filling of drums (sheet metal or plastic drums of usually 200 l content), whereby the filling process can be controlled by hand or monitored by an automatic control device that checks the empty weighing, filling and switching off the filling valve after the specified filling value has been reached supervised.

Drum filling devices of this type are equipped with a filling tube that either only dips a little into the bunghole for filling above-level mirrors or dips deeply for filling below-level mirrors and is slowly raised by a corresponding lifting device during filling.

If harmful gases or vapors are filled with liquids, and environmental protection regulations, drum filling devices of the type mentioned at the outset are required, which use suction devices to suck off the gases escaping from the drum during filling. Such suction devices are for example from the publication:
"Program for the Prevention of Health Damage from Work Agents"
the professional association of the chemical industry. These suction devices create a space encompassing the filling pipe in the filling position of the barrel filling device in the height region of the bung hole, which is sealed laterally and upwards against the filling pipe and has an opening over the bung hole below. The cited document describes two constructions.

In one of these known constructions, the suction device has an opening on a funnel which widens downwards and is placed on the drum. In a second construction shown there, the suction device rests on the barrel surface with an elastic bellows to reduce the support weight.

Both known constructions mentioned have in common that the barrel is weight-loaded during suction, that is to say during the entire filling operation. However, this leads to an influencing of the weighing process, so that such constructions are not permitted according to German calibration regulations.

The object of the present invention is therefore to create a drum filling device of the type mentioned at the outset which, with sufficient suction, allows a verifiable weighing operation.

This object is achieved with the features of the characterizing part of claim 1.

The drum filling device according to the invention has a suction device which is in the filling position of the device with its lower edge surrounding the suction opening at an all-round distance from the drum surface and the bunghole wall. This avoids any strain on the barrel during weighing. Since the edge of the suction opening is arranged at a short distance from the drum surface, there is a gap which largely limits the intake of air. In contrast to the known construction with suction funnel, in which considerable amounts of air are sucked in, air admixtures to the extracted gas are avoided as far as possible, so that the removal device connected downstream of the suction device is not overloaded by excessive amounts of gas. Adjusting the height of this gap is difficult if only one lifting device is provided, which is also intended to quickly overcome the large differences in height when the filling pipe and suction device are pulled up to change the drum. For this purpose, the invention provides that when lowering is first lowered until it touches the barrel. This can be done quickly and without complicated controls. The lifting device is then switched over and the vehicle is raised until the sensor indicates the correct altitude. During this start-up operation, the vehicle can be driven slowly so that the correct gap setting can be carried out with great precision. The barrel contact is not only advantageous for switching to reversing operation, but also gives the further advantage that it makes it possible to recognize whether the barrel has been hit correctly, that is to say in an open bunghole and not approximately in the middle of the barrel surface. The touch of the barrel can also be used to re-center the roughly pre-centered bunghole in relation to the filling pipe. Overall, this results in an extremely safe and precise filling device.

The features of claim 2 are advantageously provided. The switching signal could also be triggered by the sensor when approaching the barrel. Then there is uncertainty as to whether the barrel is actually touched, for example if the touch is used for other purposes, such as centering or bunghole detection. A very simple option is to use the load signal of the scale when touching the barrel to reverse the lifting device.

The features of claim 3 are also advantageously provided. In this way, the large difference in height from the barrel change position to the barrel touch can be overcome quickly, which speeds up the filling operation, but at the same time the suction gap height can be set very precisely in slow travel operation. For all types of lifting equipment, e.g. With hydraulic cylinders or with a rack and pinion drive, problems with load changes or play, which can occur with the exact height adjustment, can be avoided.

When using a pneumatic lifting device, the features of claim 4 are advantageously provided. When moving upward, small pressure surges are rapidly given in succession to the lifting device, which is designed, for example, as a piston / cylinder arrangement, so that it moves upwards step by step and stops after the small step at which the sensor responds. In this way, the known problems in the fine control of a pneumatic lifting device can be reduced.

The features of claim 5 are also advantageously provided. In this way, it is very easy to achieve that, when the drum comes into contact, it is recognized whether the filling pipe protrudes into an open bung hole or, for example, touches the bung surface next to the bung hole or e.g. on a bunghole closed with a lid. The geometry of the arrangement ensures that in such a case the sensor does not come sufficiently close to a part of the barrel and therefore does not indicate. If the sensor signal is missing, the filling process is not triggered and it is avoided that the filling valve opens and the liquid to be filled runs over or next to the barrel.

The features of claim 6 are advantageously provided. Only if this deepest point can dip into the bung hole under the barrel surface, will the sensor come sufficiently close to the barrel surface to be able to indicate.

• Fig. 1 eine erfindungsgemäße Faßfüllvorrichtung zur Überspiegelabfüllung,
• Fig. 2 einen Achsschnitt durch die Absaugeinrichtung der Faßfüllvorrichtung gemäß Fig. 1,
• Fig. 3 einen Ausschnitt in Darstellungsweise gemäß Fig. 1 einer Faßfüllvorrichtung für Unterspiegelabfüllung,
• Fig. 4 eine Darstellung gemäß Fig. 2 einer Variante der Füllvorrichtung.

The invention is shown schematically and by way of example in the drawings. Show it:

• 1 shows a barrel filling device according to the invention for filling over mirrors,
• 2 shows an axial section through the suction device of the barrel filling device according to FIG. 1,
• 3 shows a detail in the representation according to FIG. 1 of a barrel filling device for bottom mirror filling,
• FIG. 4 shows a representation according to FIG. 2 of a variant of the filling device.

Fig. 1 shows a side view of a complete drum filling device with a drum 1. This is on the table 2 of a scale 3, on which it was previously brought by hand or with devices not shown and aligned in the correct filling position.

A support column 4 is provided on the balance 3, which carries a lifting device 6 with an arm 5 in the preselected basic height setting. The lifting device 6 has a driver 7 which is height-adjustable in the direction of the arrow and which carries a coupling device 8, of which the upper end of a filling tube 9 is held interchangeably.

In the exemplary embodiment in FIG. 1, the filling tube 9 is designed for filling above-level mirrors. It is therefore sunk only slightly into the bung hole of the barrel 1 shown with its bunghole wall 10 into the height position shown in FIG. 2, in order then to fill the barrel from above. When the filling is complete, the lifting device 6 disengages it from the barrel 1. Fig. 1 shows a filling tube 9 of conventional design, which has at its lower end 11 a foot valve, not shown, which is switched by a valve control 12, which is arranged at the upper end of the filling tube 9. A connecting piece 13 for a filling hose 14, through which liquid to be filled in the direction of the arrow is fed from a storage tank, not shown, opens into the filling pipe 9.

In this respect, the construction shown corresponds to the prior art, which also already has gas extraction devices which extract gases escaping in the area of the bunghole when filling.

In the illustrated construction according to the invention a suction device 15 is provided, which is explained in more detail with reference to FIG. 2 in an axial section. The suction device 15 is designed as a tubular housing which concentrically surrounds the filling tube 9 in the illustrated embodiment. At the upper end of the suction device 15, a seal 16 sealing against the filling pipe 9 is provided. The interior of the suction device 15 is vented via a pipe socket 17 and a suction hose 18, through which the extracted gases lead in the direction of the arrow to suction devices (not shown) and downstream treatment devices for the extracted gases, such as devices for returning them to the liquid storage tank, combustion devices or other removal devices.

The underside of the suction device 15 is open and forms the suction opening which draws gas from below with the edge 19. The edge 19, as shown in FIG. 2, is designed with a diameter which is somewhat larger than the outer diameter of the bunghole wall 10. In the in Fig. 2 shown position of the suction device 15, the edge 19 is arranged at a low height above the surface of the barrel 1. In this position, gas emerging from the barrel in the direction of arrow 20 is drawn in. In addition, secondary air is drawn in from the atmosphere in the direction of arrow 21. The sucked-in secondary air (arrow 21) is strongly throttled when it passes through the narrow gap between the edge 19 and the surface of the barrel on the one hand and through the annular channel between the inside of the suction device 15 and the outside of the bunghole wall 10. This ensures that only a relatively small amount of secondary air is drawn in, so that the subsequent gas treatment devices can be designed for low throughputs in a cost-saving manner.

Fig. 2 shows the suction device 15 in the height position above the barrel 1, which must be observed during the entire filling process. Care must be taken to ensure that this position is maintained exactly, since touching the barrel would disrupt the weighing and, on the other hand, enlargements of the gap with the resulting increase in the amount of secondary air sucked in should be avoided.

Therefore, a sensor 22 is arranged on the suction device 15, which is designed such that it determines the distance to the barrel surface in an inductive manner, for example. Depending on this, the lifting device 6 can be adjusted accordingly.

During filling breaks, especially when changing the barrel, 9 drops can fall down from the raised filling tube, which would have unpleasant consequences in the case of highly toxic liquids. For this purpose, it is customary to arrange a drip tray under the raised filling tube.

In the embodiment shown, such a drip tray 27 is provided on a lateral movement device 28, which is attached to the lifting device 6 via an arm 29. The height of the drip tray 27, in which it is arranged to be laterally displaceable in the direction of the arrow, is selected such that after pulling up the suction device 15 into the upper end position, the drip tray 27 grips with the smallest possible height distance under the edge 19 of the suction device. Then the suction device can continue to run even during the barrel change and continue to suck off the vapors which are emitted by drops hanging from the filling tube. The narrow gap between the edge 19 of the suction device 15 and the drip tray 27 limits the intake secondary air.

The movements described in the above description of the barrel filling device shown can be controlled in the simplest case by hand. However, automatic control is preferable. A control unit 30 is provided for this purpose. This is electrically connected by lines 31 to 35 to the scale 3, the lateral movement device 28 for the drip tray 27, to the sensor 22 for determining the height of the suction device 15 above the barrel 1, to the lifting device 6 and to the valve control 12 of the filling tube 9. It controls the processes as follows:

First, the scale 3 carries out an empty weighing when the drum is empty. Then the lifting device 6 is actuated in order to deposit the filling pipe 9 and the suction device 15 down to the barrel. The sensor 22 now determines the altitude above the barrel and the lifting device 6 is controlled accordingly in order to move to a lifting position according to FIG. 2. The valve controller 12 is then actuated to open the valve.

It is now filled until the scale 3 reports that the filling weight has been reached. Then the valve control 12 is actuated to close the valve, the lifting device 6 moves the filling pipe and the suction device upwards, to a position coordinated with the height of the drop tray 27 and then by appropriately actuating the lateral movement device 28 under the edge 19 the suction device 15 moves. Then the filled one can be changed to an empty one for a new filling cycle.

FIG. 3 shows an embodiment variant of that in FIG. 1 Barrel filling device shown, in which only the parts necessary for the description of the embodiment are shown in a section. Corresponding parts are provided with the same reference numerals as in FIGS. 1 and 2.

1 with the only difference that it is not equipped for over-mirror filling, but for under-mirror filling. The filling tube 9 'must be moved in height during the filling process and immersed considerably deeper into the barrel. During the filling process, the lower end 11 of the filling tube 9 'should always reach below the respective filling level. This ensures that filling is carried out more smoothly and without splashing, which is particularly necessary in the case of highly foaming liquids. The filling tube should not stand still during the filling process, but rather be pulled up with increasing filling level in order to limit its external wetting by the liquid to be filled to a height range of a few centimeters. The suction device 15 'should be fixed in height during the filling process.

For this purpose, as shown in FIG. 3, a further lifting device 36 is arranged on the driver 7 of the lifting device 6, which carries the suction device 15 via the arm 26, which in turn has a height-controlled driver 37, the coupling device 8 for the upper end of the filling pipe 9 'Carries, which is naturally much longer in this case, but otherwise identical to the filling tube 9 shown in Fig. 1 is formed.

The height position of the suction device 15 is thus controlled, as in the embodiment of FIG. 1, by the lifting device 6, while independently of it the lifting device 36, the filling tube 9 'can be moved in height.

The suction device 15 is essentially unchanged in the same way as the construction shown in FIGS. 1 and 2 with the only difference that the ring seal 16 for sealing the suction device 15 on the filling pipe is to be designed as a sliding seal in this case.

The control unit 30 'is largely identical to the control unit 30 of the embodiment of FIG. 1. It only has a further control line 38 for the additional lifting device 36.

As can be seen from the above description, it is important for the height adjustment with the lifting device 6 that, after touching the barrel, the ramp is raised to the exact extent that (see FIG. 2) there is a correct gap between the edge 19 of the suction opening and the barrel surface. This should be as small as possible so that little secondary air is sucked in through this gap, on the other hand it must be avoided with certainty that the suction device touches the barrel surface, since the weighing would then be falsified. When moving down from above into the height position shown in FIG. 2, the sensor shows the correct height above the barrel, but stopping when driving downwards would never be possible so precisely that the exact gap is maintained. The standstill times of the lifting device 6, dieverses movement or the like. hindering.

Therefore, it is first placed on the barrel and then moved upwards until the sensor 22 indicates the correct altitude. It can therefore be driven quickly to save time while downhill is then driven very slowly in order to precisely adjust the correct gap height. At the exact moment when the sensor 22 indicates the correct height, the drive can be switched off or a brake can be actuated. The gap height of the edge 19 above the barrel surface can thus be adjusted with millimeter precision.

The sensor 22 shown in the figures can be designed, for example, as an inductive sensor that detects the surface of an iron barrel electromagnetically, but it can also be provided, for example, with a mechanical contact switch, an optical distance sensor or the like.

The sensor can be used as a signal generator for switching from downward travel to upward travel. However, it is advantageous to use the display of the scale to switch over if the scale briefly shows a weighing load when the drum is touched. In this way, the time of touchdown can be determined precisely and switched immediately.

The correct height adjustment of the gap of the suction device, that is, the edge 19 above the barrel surface, becomes particularly difficult if a simple pneumatic actuating device is used as the lifting device 6, since the amount of air supplied does not necessarily correspond to a certain distance, depending on load changes and pressure fluctuations. Therefore, in an advantageous embodiment, when driving upwards, that is to say after barrel contact and switching the lifting device 6 to upward travel, short pressure surges are used which are fed to the pneumatic lifting device. These cause a "stuttering" upward movement in small steps. As soon as the sensor 22 indicates the correct altitude, it is interrupted and, if necessary applied a brake. The height error can then only be one increment. With very small pressure surges and thus small steps, the altitude can be set very precisely.

The barrel contact when driving down can also advantageously be used to recognize whether a bung hole has actually been hit, as shown in FIG. 2. The barrels are aligned beforehand, but incorrect actuations can occur, so that the filling tube 9 does not come down over a bung hole, but rather, for example, over the flat barrel surface. Then make sure that the filling process is stopped and that the filling valve is not opened first. Otherwise, large amounts of toxic liquid could leak into the open.

Fig. 4 shows a variant of the embodiment of Fig. 2, in which this is explained.

On the suction device 15, a dashed arm 30 is provided inside, which extends down through the bung hole to below the barrel surface. If, as shown, the suction device 15 touches exactly on an open bung hole 10, the arm 30 extends through the bung hole into the interior of the barrel without touching anywhere. The sensor 22 can now arrive sufficiently close to the surface of the drum to display it.

However, if placed in the middle of the barrel surface, the lower end of the arm 30 would touch the barrel surface and hold the sensor 22 at such a distance from the barrel surface that it cannot display. During the subsequent upward movement, the suction device 15 would continue to move upward without reaching a sensor display. It then turns out an error message and the filling process is interrupted.

Even if it is correctly placed on the bung hole, but this is closed by a cover, the arm 30 prevents the sensor 22 from approaching the barrel surface by placing it on the cover. So there is always a correct indication of whether an open bung hole has really been hit.

Instead of the arm 30, the filling pipe 9˝ can also be used for these purposes if it is arranged with its lower end sufficiently deep below the sensor 22.

The placement on the barrel advantageously also serves a further purpose, which is explained with reference to FIG. 4. The filler pipe 9˝ is formed in the area of the upper edge of the bung 10 conically widening upwards. When fitting, the cone hits the edge of the bung hole and centers it fine, which is often necessary if the centering device that is working before the start of the filling process does not work precisely enough.

Claims (6)

1. Drum-filling apparatus with a balance monitoring the filling weight and a suction device which in the filling position is arranged in the vicinity of the bung hole and whose suction opening engages around the filling pipe, characterised in that the suction device (15, 15′) is so arranged in the filling position (Fig. 2, Fig. 3) of the apparatus that the edge (19) of the suction opening is situated at a small height above the surface of the drum (1), that the suction device (15, 15′) is supported by a lifting device (6) which is controlled by a sensor (22) which determines the vertical distance of the suction device above the surface of the drum (1) and that the lifting device is constructed so as to be controlled so that when moving down towards the drum it moves initially downwards until the suction device or the filling pipe contacts the drum and then upwards until the sensor indicates the correct height.

2. Drum-filling apparatus as claimed in claim 1, characterised in that the lifting device (6) is so controlled in dependence on the balance (3) that on contact with the drum the balance indication of the superposed loading effects the switching over of the lifting device from downward movement to upward movement.

3. Drum-filling apparatus as claimed in one of the preceding claims, characterised in that the lifting device (6) is constructed to move rapidly downwards and slowly upwards until it reaches the filling position height.

4. Drum-filling apparatus with a pneumatic lifting device as claimed in one of claims 1 or 2, characterised in that for the purpose of moving upwardly the lifting device (6) is acted on by successive small pressure pulses.

5. Drum-filling apparatus as claimed in one of the preceding claims, characterised in that the shape of the suction device (15, 30) and/or the filling pipe (9, 9′, 9˝) are so selected that on lowering of the filling pipe the sensor (22) can only respond to an open bung hole (10).

6. Drum-filling apparatus as claimed in claim 5, characterised in that at the filling position the lowest point (30, 9˝) of the suction device or filling pipe in the bung hole (10) is below the surface of the drum.

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