DE20100972U1 - Device for suction of coarse material - Google Patents

Description

TERMEER STEIN.MEÜST&FI-&

GBP

PATENT ATTORNEYS - EUROPEAN PATENT ATTORNEYS

Dr. Nicolaus ter Meer, Dipl.-Chem. Peter Urner, Dipl.-Phys.
Gebhard Merkle, Dipl.-Ing. (FH)
Mauerkircherstrasse 45
D-81679 MUNICH

Helmut Steinmeister, Dipl.-Ing. Manfred Wiebusch

Artur-Lade beck-Strasse D-33617 BIELEFELD

51

ABS POl / Oil

Wi/li 17.1.2001

Friedhelm Albrecht

Oberveischederstr. 5

57462 Olpe / Oberveischede

DEVICE FOR SUCTION OF COARSE MATERIAL

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DEVICE FOR SUCTION OF COARSE MATERIAL

The invention relates to a device for sucking off coarse material, with a filter container which is connected to a suction fan via a filter and to which a suction line is connected.

During excavation work, for example when creating earth boreholes, trenches or shafts, it is common practice to extract the excavated material, such as drilling debris, loose soil or other filled materials, using a powerful suction fan. The material sucked in via a suction nozzle and the suction line is collected in the filter container under negative pressure, while the suction fan is protected against dust and fine-grained material by the filter. The filter container and the associated suction fan are usually mounted as a transportable unit on a truck or similar. The filter container should have as large a capacity as possible to enable long operating times. When the capacity is exhausted, the filter container must be ventilated and emptied or replaced with an empty filter container. This results in relatively long interruptions in operation.

The object of the invention is to provide a device which enables an extension of the operating time for a given capacity of the filter container.

This object is achieved according to the invention in that a pre-separator is arranged in the suction line, which has a discharge device for discharging separated material while the suction fan is running.

The pre-separator separates coarse-grained material before it enters the filter container, so that less material reaches the filter container and the capacity is therefore only exhausted after a longer period of operation. Since the fine-grained material that cannot be separated in the pre-separator generally has a higher bulk density than a mixture of fine-grained and coarse-grained material, the capacity of the filter container is also used more efficiently in the solution according to the invention. It is also often a desired side effect of the invention that

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The pre-separator already pre-sorts the excavated material.

The material retained in the pre-separator is removed at intervals using the discharge device, so that the pre-separator itself only needs to have a small capacity. In order to open the locking mechanism of the discharge device against the negative pressure prevailing in the pre-separator, the pre-separator only needs to be ventilated for a short time. However, the operation of the powerful suction fan does not need to be interrupted. Overall, this results in a considerable extension of the usable operating times.

Advantageous embodiments of the invention emerge from the subclaims.

Since the pre-separator is only intended to hold back coarser-grained material, it does not need to have its own filter device. It can simply be formed by a vacuum chamber in which the coarse-grained material settles due to the calming of the air flow. The discharge device preferably has a lock chamber arranged below the vacuum chamber, which can be closed off largely hermetically from the environment. When the separated material in the vacuum chamber has reached a certain fill level, a bottom flap or a bottom valve of the vacuum chamber is opened so that the material falls into the lock chamber by gravity. Since the lock chamber is sealed off from the environment in this state, it is evacuated by the suction fan so that the suction operation can continue uninterrupted or at least be resumed before the bottom flap is closed. When the bottom flap is closed again, the lock chamber is ventilated and an outlet of the lock chamber is opened so that the material falls out. The material discharged in this way can be temporarily stored on site or directly picked up and transported away by a transport vehicle.

In a particularly preferred embodiment, the vacuum chamber has a level monitor that automatically activates the lock mechanism when a certain level is reached. The level can be detected using optical or mechanical sensors or optionally

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by means of a weighing device which records the weight of the contents or the total weight of the vacuum chamber with contents.

If the material discharged from the outlet of the lock chamber is to be collected directly in a transport device, it is convenient if the opening and closing of the outlet of the lock chamber can be controlled manually or at least the automatic operation can be temporarily blocked manually until the transport device has been brought into position.

The bottom flap of the vacuum chamber can be designed in such a way that, when the lock chamber is ventilated, it is held in the closed position by the pressure gradient between the lock chamber and the vacuum chamber. Emptying the vacuum chamber into the lock chamber can then be triggered simply by briefly ventilating the vacuum chamber or evacuating the lock chamber. A manually operated or motor-operated mechanism or a closing spring can be provided to close the bottom flap. In the final phase, the closing process can also be supported by ventilating the lock chamber again.

In a modified embodiment, a diaphragm valve is provided instead of the bottom flap, which is held in the closed position by the pressure difference between the lock chamber and the vacuum chamber.

In the following, embodiments of the invention are explained in more detail with reference to the drawing.

Show it:

Figure 1 shows a schematic section through a device for

Vacuuming of excavated soil;

Figures 2 to 4 show a pre-separator of the device according to Figure 1 in different operating phases; and

Figure 5 shows a pre-separator according to another embodiment

shape.

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The device shown in Figure 1 is used to suck up excavated earth using a suction line 10 which is connected to a filter container 14 via a pre-separator 12. The filter container 14 is in turn connected to a powerful suction fan 18 via a filter 16 arranged in its upper area. The filter 16 retains dust and fine-grained materials which settle in the lower area of the filter container 14. When the capacity of the filter container 14 is exhausted, the filter container must be emptied or replaced. For this purpose, the filter container 14 and the suction fan 18 are mounted on a transport vehicle 20 in the example shown.

The pre-separator 12 has a pressure-tight sealable vacuum chamber 22 in which the air flow entering via the upstream branch 24 of the suction line 10 can temporarily calm down before the air is passed on to the filter container 14 via the downstream branch 26. This means that coarse-grained components of the sucked-in material settle in the vacuum chamber 22 and thus do not even reach the filter container 14. The bottom of the vacuum chamber 22 tapers in a funnel shape to an airtight bottom flap 28, which forms the inlet of a lock chamber 30 arranged directly below the vacuum chamber 22. At the lower end, the lock chamber 30 is closed by a discharge flap 32, which is connected to a discharge shaft 34 at the bottom. The discharge chute has a certain ground clearance so that a collecting container, a conveyor belt or other transport device can be placed underneath to transport the discharged material away.

A ventilation valve 36 is arranged at the upper end of the vacuum chamber 22. A level monitor 38 is arranged in the wall of the vacuum chamber 22 at a certain height that corresponds to the maximum permissible fill level in the vacuum chamber. A second level monitor 40 is located directly above the bottom flap 28.

Figure 1 illustrates the state of the pre-separator 12 during suction operation. The ventilation valve 36 and the bottom flap 28 are closed, so that a certain negative pressure prevails in the vacuum chamber 22. The bottom flap 28 is held in the closed position by a closing spring (not shown). However, this closing spring is dimensioned such that it alone

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is not sufficient to hold the bottom flap in the closed position when the weight of the separated material acts on the bottom flap at maximum fill level in the vacuum chamber 22. The closing force with which the bottom flap 28 is nevertheless held in the closed position is based primarily on the pressure difference between the interior of the vacuum chamber 22 and the lock chamber 30, which is at atmospheric pressure in the state shown in Figure 1.

When the level monitor 38 detects that the maximum level in the vacuum chamber 22 has been reached, the level monitor 38 sends a short signal pulse to the ventilation valve 36, so that this valve opens briefly. Although the suction fan 18 remains in operation, the pressure difference between the vacuum chamber 22 and the lock chamber 30 is reduced, so that the bottom flap 28 gives way.

As soon as the bottom flap 28 is opened a crack, as shown in Figure 2, the pressure difference between the vacuum chamber 22 and the lock chamber 30 continues to decrease, since the coarse-grained material lying on the bottom flap is relatively permeable to air. At this moment, the ventilation valve 36 can be closed again, so that the suction operation continues practically without interruption. Although the vacuum chamber 22 is evacuated again, the suction is not sufficient to close the bottom flap 28 again. Due to the weight of the material resting on it, the bottom flap opens completely, so that the material falls into the lock chamber 30, as shown in Figure 3. Since the discharge flap 32 closes largely airtight, in this state the same negative pressure prevails in the lock chamber 30 as in the vacuum chamber 22.

If the lower level monitor 40 detects that the vacuum chamber 22 is completely empty, an optical or acoustic signal is generated, which prompts the operator to close the bottom flap 28 manually using an actuating rod (not shown). Alternatively, the bottom flap 28 can also be automatically returned to the closed position by a motor drive or by spring force. Since there is no longer any material on the bottom flap 28, the closing force required is significantly smaller than in the state shown in Figure 1.

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When the bottom flap 28 returns to the closed position, the lock chamber 30 is ventilated again. In the simplest case, this ventilation can be achieved automatically by the discharge flap 32 not closing completely tightly, so that a certain leakage flow enters the lock chamber 30. As the fill level in the vacuum chamber 22 increases again, the closing force acting on the bottom flap 28 also increases until the lock chamber 30 is back at atmospheric pressure.

When this state is reached, the discharge flap 32 is opened so that the material falls out of the lock chamber 30, as shown in Figure 4. The opening of the discharge flap 32 can take place - automatically or by operator intervention - at any time before the fill level in the vacuum chamber 22 has reached the maximum value again. When the discharge flap 32 is then closed again, the state shown in Figure 1 is reached again and the pre-separator 12 is ready for a new discharge process.

Instead of ventilating the vacuum chamber 22 using the ventilation valve 36 to trigger the discharge process, it is also possible in a modified embodiment to briefly connect the lock chamber 30 to the downstream branch 26 of the suction line via a valve and a line (not shown) so that the lock chamber is evacuated. This also leads to a reduction in the pressure gradient between the lock chamber 30 and the vacuum chamber 22 and thus to an automatic opening of the bottom flap 28.

Figure 5 shows a further embodiment which differs from the embodiment according to Figures 1 and 4 in that the bottom flap 28 is replaced by a diaphragm valve 42. This diaphragm valve has two diaphragms 44, for example in the form of wear-resistant rubber mats, which together form a tube- or funnel-shaped structure. If there is a pressure gradient between the lock chamber 30 and the vacuum chamber 22, the two diaphragms 44 lie close to one another, as shown in solid lines in Figure 5. If the pressure gradient is reduced by ventilating the vacuum chamber 22 or by evacuating the lock chamber 30, the diaphragms 44 move apart due to the weight of the material resting on them and they provide an outlet into the lock chamber.

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chamber 30 is free, as shown in dashed lines in Figure 5. When the vacuum chamber 22 is completely emptied and the lock chamber 30 is ventilated again, the diaphragm valve 42 automatically returns to the closed position. 5

Claims (8)

1. Device for suctioning coarse material, with a filter container ( 14 ) which is connected to a suction fan ( 18 ) via a filter ( 16 ) and to which a suction line ( 10 ) is connected, characterized in that a pre-separator ( 12 ) is arranged in the suction line ( 10 ), which has a discharge device ( 28 ; 42 ) for discharging separated material when the suction fan is running. 2. Device according to claim 1, characterized in that the pre-separator is formed by a vacuum chamber ( 22 ) in which a part of the sucked-in material settles due to a calming of the air flow. 3. Device according to claim 2, characterized in that the discharge device has a lock chamber ( 30 ) arranged below the vacuum chamber ( 22 ) and which can be closed in a largely airtight manner with respect to the environment, and a closure member ( 28 ; 42 ) arranged between the vacuum chamber ( 22 ) and the lock chamber ( 30 ), which is acted upon in the opening direction by the weight of the separated material and is held in the closed position by the pressure gradient prevailing between the vacuum chamber ( 22 ) and the lock chamber ( 30 ). 4. Device according to claim 3, characterized in that the closure member is a bottom flap ( 28 ) of the vacuum chamber ( 22 ). 5. Device according to claim 3, characterized in that the closure member is a diaphragm valve ( 42 ). 6. Device according to one of claims 3 to 5, characterized in that the closure member ( 28 ; 42 ) opens automatically when the pressure gradient between the vacuum chamber ( 22 ) and the lock chamber ( 30 ) is reduced. 7. Device according to claim 6, characterized by a ventilation valve ( 36 ) for briefly ventilating the vacuum chamber ( 22 ). 8. Device according to one of the preceding claims, characterized by a level monitor ( 38 ) which automatically actuates the discharge device ( 28 ; 42 ) when the level in the pre-separator ( 12 ) reaches a predetermined value.