DE102021126632A1 - Mixing device with spray device and method for operating a mixing device - Google Patents

Abstract

A mixing device (1) for mixing material to be mixed (16) has a mixing chamber (2) and an emptying device (13) with an emptying flap (6) for emptying the mixing chamber (2). The mixing chamber (2) and the discharge flap (6) each have closing surfaces (2a, 6a) which cooperate to close the mixing chamber (2). The mixing device has a spray device (11) which is designed to apply an anti-adhesive agent (12) to an area of the emptying device (13) and/or the mixing chamber (2) below the closing surfaces (2a, 6a).

Description

The present invention relates to a mixing device and a method for preventing material to be mixed from adhering to the mixing device. The material to be mixed can in particular be a raw rubber mixture.

When processing raw rubber material, the raw material, which is usually a mixture of different components, is mixed in one process step. After mixing, the mixing apparatus must be emptied. When emptying the mixing apparatus, the problem can arise that mixed material sticks in an ejection area and the mixing apparatus malfunctions due to an emptying error. The sticky mix then has to be removed manually with scrapers when the plant is at a standstill. The emptying area is often difficult to access and working in this area is associated with high risks.

The DE 10 2017 212 378 A1 discloses a mixing device in which a lubricant is applied to sealing, anti-equal edge surfaces of a chamber housing or saddle.

It is an object to provide a mixing chamber with improved properties. In particular, adhesion of mixed material should be reduced or prevented.

According to a first aspect of the present disclosure, a mixing device has a mixing chamber and an emptying device having an emptying flap for emptying the mixing chamber. The mixing device is designed for mixing a material to be mixed. In particular, it can be a raw rubber mixture. The emptying flap can close an opening in the bottom of the mixing chamber and release it for emptying. The discharge device and the mixing chamber each have closing surfaces which cooperate to close the mixing chamber. The mixing device has a spray device which is designed to apply an anti-adhesive agent to an area of the discharge device and/or the mixing chamber below the closing surfaces.

The closing surfaces close off the mixing chamber at the bottom and are designed as surfaces inclined in opposite directions to one another. It is also possible that there is a small gap between the closing surfaces, from which, for example, lubricant can escape from the mixing chamber.

The anti-adhesive agent is thus not applied to the closing surfaces, but to areas below the closing surfaces. It has been found that when the discharge flap is opened or closed, mixed material can unintentionally get into an area below the closing surfaces and stick there. This can prevent the mixing chamber from closing properly after it has been emptied and can lead to a malfunction.

For example, there is a cavity between the emptying device and a wall of the mixing chamber. The spray device can be designed to wet surfaces that adjoin the cavity with the anti-adhesive agent. When the discharge flap is opened, the mix can simply fall out of this area due to wetting and the resulting poor adhesion. Other cavities in the emptying device, which are below the closing surfaces and in which mixed material can accumulate, can also be wetted with the anti-adhesive agent. For example, such a cavity can be located between carriers of the discharge flap.

A further advantage of wetting surfaces below the closing surfaces is that the entry of anti-adhesive agent into the mixing chamber can be prevented. The spray device can be designed to release the anti-adhesive agent when the mixing chamber is closed. In this way, contamination of the mixing chamber with the anti-adhesive agent can be avoided.

In addition, the spray device can be easily integrated into the mixing device. For example, the spray device is attached to a wall on the underside of the mixing chamber. The spray device does not have to be integrated into a wall. For example, the spray device can also be fitted subsequently in a mixing device. However, it is also possible for the spray device to be integrated in a wall. In particular, the spray device can be arranged partially or completely within a wall of the mixing device, for example a wall of the mixing chamber, below the closing surfaces.

The anti-adhesion agent can have water as at least the main component. The anti-adhesion agent can also be water. The use of water as an anti-adhesion agent has the advantage that the anti-adhesion agent wets the surfaces but can evaporate relatively quickly and does not accumulate on the surfaces. This means that there is little or no mixing and contamination of the material to be mixed with the anti-adhesive agent.

For example, the spray device is arranged between the emptying device and the mixing chamber. For example, the emptying device has a shaft to which the emptying flap is attached. The mixing chamber is opened by rotating the shaft. For example, the spray device is arranged between the shaft and the mixing chamber.

The mixing device can have a control device for controlling the spray device. The control device is designed, for example, to control dispensing of the anti-adhesive agent as a function of process steps of the mixing device. Such process steps are, for example, the progress of the mixing process and the actuation of the emptying device.

For example, the control device is designed to control the spray device for dispensing the anti-adhesive agent when the mixing chamber is closed. For example, the anti-adhesive agent is only released shortly before the emptying flap is opened.

The control device can be designed to control the spray device in such a way that the release of the anti-adhesive agent is terminated at the latest when the discharge flap is fully opened. For example, delivery is already ended before the discharge flap opens, or delivery is ended during the opening process.

According to a further aspect of the present disclosure, a method for operating the mixing device described above comprises the following steps. The material to be mixed is mixed in the mixing chamber. After the end of the mixing process, the discharge flap is opened to empty the mixing chamber so that the mixed material can fall down through the discharge flap and out of the mixing chamber. During the process, anti-seize agent is dispensed from the spray device onto the area of the discharge device and/or the mixing chamber below the closure surfaces.

For example, the anti-adhesive agent is released before the discharge flap is opened. Delivery can be stopped again before opening, so that delivery only takes place when the discharge flap is closed. For example, the anti-adhesive agent is released just before the discharge flap opens.

It is also possible to stop the release of the anti-seize agent even during the opening process. In particular, the opening can be ended at the latest when, due to the movement of the emptying flap, the anti-adhesive agent no longer reaches the intended areas of the emptying device. For example, the delivery is terminated at the latest when the discharge flap is rotated by 90°.

The present invention comprises several aspects, in particular devices and methods. The features, properties and embodiments described for one of the aspects should also apply correspondingly to the other aspect.

In addition, the description of the objects given here is not limited to the specific embodiments. Rather, the features of the individual embodiments can be combined with one another, insofar as this is technically sensible.

The objects described here are explained in more detail below using schematic exemplary embodiments.

• 1 im Querschnitt eine Mischvorrichtung mit geschlossener Entleerungsklappe gemäß einer Ausführungsform,
• 2 die Mischvorrichtung aus 1 mit geöffneter Entleerungsklappe,
• 3 Verfahrensschritte zur Vermeidung einer Anhaftung von Mischgut bei einer Mischvorrichtung gemäß einer Ausführungsform.

Show it:

• 1 in cross section a mixing device with a closed discharge flap according to one embodiment,
• 2 the mixing device off 1 with open discharge flap,
• 3 Method steps for preventing material to be mixed from adhering to a mixing device according to one embodiment.

In the following figures, the same reference symbols preferably refer to functionally or structurally corresponding parts of the various embodiments.

1 shows an embodiment of a mixing device 1. The mixing device comprises a mixing chamber 2. The mixing chamber 2 can be filled from above via a loading shaft 3. FIG. For example, the mixing chamber 2 is filled with a mixture 16 in the form of a raw rubber mixture.

In the exemplary embodiment, two rotors 4 are arranged in the mixing chamber 2, which rotors can, for example, rotate in opposite directions. In other embodiments, any number of rotors, which can rotate in different or the same directions, can be used.

A discharge shaft 5 adjoins the mixing chamber 2 at the bottom. In the exemplary embodiment, an opening is provided in a wall 15 of the mixing chamber 2 on the floor 17 through which the material to be mixed 16 can be conveyed into the discharge shaft 5 . The mixing material 16 is conveyed by the rotors 4 and is additionally favored by the effect of gravity.

The mixing device 1 has an emptying device 13 with an emptying flap 6 . The opening in the wall 15 is closed by the emptying flap 6 . The discharge flap 6 remains closed during the mixing process. In order to hold the discharge flap 6 in the closed position, a latch 7 is provided which is pushed under the discharge flap 6. In the present exemplary embodiment, the bolt 7 is embedded in a wall of the emptying shaft 5 and can be opened by sliding it to the side.

The discharge flap 6 fits into the wall 15 of the mixing chamber 2, so that the bottom 17 of the mixing chamber 2 is closed. Here are closing surfaces 6a of the emptying flap 6 closing surfaces 2a of the wall 15 opposite. The closing surfaces 6a have complementary surfaces, ie surfaces inclined in opposite directions, and work together to close the mixing chamber 2 .

It can be advantageous if the closing surfaces 2a, 6b do not close completely, but instead a gap remains between the closing surfaces 6a of the discharge flap 6 and the closing surfaces 2a of the wall 15 of the mixing chamber 2 even when the discharge flap 6 is in the closed state. For example, lubricants or similar undesirable substances can escape from the mixing chamber 2 through the gap.

The discharge flap 6 is attached to a shaft 9 . For example, the discharge flap 6 is attached to the shaft 9 via a support arm 8 . There can also be two support arms 8 which are arranged at a distance from one another.

There is a hollow space 10 between the shaft 9 and the closing surfaces 2a, 6a. The hollow space 10 is present, among other things, in order to ensure that the shaft 9 can rotate and that the discharge flap 6 closes properly.

The mixing device 1 has a spray device 11 which is designed to apply an anti-adhesive agent 12 to surfaces which adjoin the cavity 10 . These are, for example, a surface 6b of the emptying flap 6 below the closing surface 6a or surfaces 2b of the wall 15 below the closing surface 2a of the wall 15. These surfaces 2b, 6b are not designed to complement one another, ie surfaces not inclined in opposite directions. The designation "below" refers to the closed state of the emptying flap 6 . "Below" means that a component is located further down in the direction of gravity.

It has been found that material to be mixed 16 can unintentionally get into this cavity 10 when opening or closing the discharge flap 6 and can stick there to the surface 6b of the discharge device 13 or to the surface 2b of the mixing chamber 2 . For example, the material to be mixed 16 can also stick to or between the carrier arms 8 of the emptying device 13 . This can prevent the discharge flap 6 from closing, so that the mixing device 1 malfunctions.

The spray device 11 is designed to apply the anti-adhesive agent 12 to a surface of the emptying device 13 and/or the wall 15 of the mixing chamber 2 below the closing surfaces 2a, 6a. For example, the spray device 11 is designed to apply the anti-adhesive agent 12 when the emptying flap 6 is closed. In this way it can be prevented that the anti-adhesive agent 12 gets into the mixing chamber 2 . For example, the spray device 11 is designed in the form of one or more nozzles.

The anti-adhesion agent 12 is a liquid, for example. In particular, the anti-adhesive agent can be water or have water as the main component. A main component is present, for example, if the water content is at least 70% by volume. For example, the water content is at least 90% by volume. The anti-adhesion agent 12 can also be applied in the form of steam.

The use of water as an anti-adhesion agent has the advantage that the anti-adhesion agent 12 wets the surfaces, but can evaporate relatively quickly and does not collect on the surfaces. As a result, there is little or no contamination of the mix with the anti-adhesive agent.

For example, the material to be mixed 16 and/or the wall 15 of the mixing chamber 2 has a temperature in the range of 150°C, which is well above the evaporation temperature of water of 100°C. It is also possible to use a different anti-adhesion agent that has a vaporization temperature well below 150°C.

In addition to this, the discharge flap 6 and/or the mixing chamber 2 can have a non-stick coating on the surfaces that come into contact with the material to be mixed 16 . For example, the surfaces are chrome-plated or coated with Teflon. The chrome plating can prevent or at least reduce the adhesion of the material to be mixed 16 .

The mixing device 1 can have a control device with which the spray device 11 is controlled. The controller can also control the mixing process. The control of the spraying device 11 can be coupled to the procedure in the mixing process. For example, the anti-adhesive agent 12 is applied shortly before the emptying flap 6 is opened.

The anti-adhesive agent 12 is applied, for example, only in the form of a brief spray burst, so that the surfaces of the emptying device 13 are sprayed in a targeted manner and the anti-adhesive agent 12 is not sprayed into the emptying shaft 5 when the emptying flap 6 is open. It can thus be prevented that the anti-adhesion agent 12 is applied in an undirected manner or excessively and leads to contamination.

It is also possible to retrofit already existing mixing devices 1 with the spray device 11 . For example, the spray device 11 can be subsequently attached to a wall 15 of the mixing chamber 2, for example screwed on. This is easily possible since the spray device 11 is not arranged on the closing surfaces 2a, 6a of the mixing chamber 2 or the discharge flap 6, but in a cavity 10 below the mixing chamber 2. It is therefore not necessary to install the spray device 11 in existing surfaces to embed This allows for relatively easy and inexpensive retrofitting.

The spray device 11 is arranged in particular in an area on which normally little or no pressure is exerted, for example by mixed material 16 . Thus, it is not necessary to discharge the anti-adhesion agent 12 under high pressure, so that the spray device 11 can be realized inexpensively. In contrast, when the spray device 11 is integrated into the closing surfaces 2a, 6a, it must be taken into account that the material to be mixed 16 that is located between the closing surfaces 2a, 6a is compressed and pressed against the closing surfaces 2a, 6a and thus also the spray device 11 when it is closed .

The spray device 11 can have a separate control device or an existing control device of the mixing device 1 can be used to control the spray device 11 .

It is also possible to attach the spray device 11 to the emptying device 13 . In this case, the spray device 11 can be moved when the discharge flap 6 is opened and closed. In this case, it is also possible to actuate the spray device 11 with the emptying flap 6 open in such a way that the anti-adhesive agent is applied to the emptying device 13 .

In 2 is the embodiment off 1 shown with the emptying flap 6 open. The bolt 7 is pushed to the side.

The spray device 11 is controlled here in such a way that no anti-adhesive agent is released when the emptying flap 6 is open. The spray device 11 is controlled, for example, in such a way that the delivery begins before or during the opening of the discharge flap 6 and ends during the opening process. It is also possible to end the release of the anti-adhesive agent 12 at the latest when the spray device 11 can no longer wet the intended surfaces of the emptying flap 6 due to the rotary movement of the emptying flap 6 . For example, this state can be reached when the discharge flap 6 has rotated 90° away from the closed state.

If the discharge flap 6 is open, the material to be mixed can fall down from the mixing chamber 2 into the discharge chute 5 . Mixed material 16 that has reached the discharge flap 6 from the side can also fall down due to the wetting of the surfaces with the anti-adhesive agent.

The discharge flap 6 can then be closed without mixed material 16 that has gotten stuck blocking the pivoting movement or the closing of the discharge flap 6 . The bolt 7 can then be pushed back under the closed emptying flap 6 to fasten the closed emptying flap 6 .

In 3 process steps for preventing material to be mixed from adhering to a mixing device are shown schematically. It can be one in the 1 and 2 acting mixing device shown.

The mixing device 1 has a control device 14 which can control the rotors 4 of the mixing chamber 2 , the spray device 11 and the emptying device 13 . It is also possible that separate control devices are present. Process steps A, B, C, D are shown schematically over time T.

In a first step A, the material to be mixed 16 is mixed in the mixing chamber 2 by the rotating rotors 4 .

In a step B, the spray device 11 is controlled to release the anti-adhesive agent. The spray device 11 can be controlled by the control device Device 14 can be controlled in such a way that the anti-adhesive agent 12 is released before the end of the mixing process. It is also possible to release the anti-adhesive agent 12 only after the mixing process has ended. For example, the anti-adhesive agent 12 is released shortly before the emptying flap 6 opens. The dispensing of the anti-adhesive agent 12 can already be terminated again before the emptying flap 6 is opened. It is also possible to release the anti-adhesive agent 12 during the opening process. In this case, the delivery is terminated, for example, when the discharge flap 6 is partially opened, for example at the latest when the shaft 9 rotates by 90°.

In a step C, the emptying device 13 is activated so that the emptying flap 6 opens. The rotors 4 in the mixing chamber 2 can continue to turn during opening and during the entire emptying process. In this way, the material to be mixed 16 can be conveyed out of the mixing chamber 2, it being possible for the material to be mixed 16 to also be conveyed into a cavity 10 below the closing surfaces 2a, 6a. Due to the anti-adhesive agent 12 applied, the material to be mixed 16 can be prevented from adhering, so that the material to be mixed 16 can fall downwards, in particular into a discharge chute 5 .

In a step D, the emptying flap 6 is closed again and can also be locked at the end.

Reference List

1

mixing device

2

mixing chamber

2a

closing surface

2 B

surface

3

feed chute

4

rotor

5

drainage shaft

6

discharge flap

6a

closing surface

6b

surface

7

bars

8th

carrier arms

9

Wave

10

cavity (below mixing chamber)

11

spray device

12

non-stick agent

13

emptying device

14

control device

15

wall

16

mix

17

Floor

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102017212378 A1 [0003]

Claims (10)

Mixing device (1) for mixing material to be mixed (16), having a mixing chamber (2) and an emptying device (13) with an emptying flap (6) for emptying the mixing chamber (2), the mixing chamber (2) and the emptying flap (6) each Having closing surfaces (2a, 6a) which cooperate to close the mixing chamber (2), and having a spraying device (11) which is designed to apply an anti-adhesive agent (12) to an area of the emptying device (13) and/or the mixing chamber ( 2) to apply below the closing surfaces (2a, 6a). Mixing device (1) after claim 1 , in which the anti-adhesive agent (12) has at least water as the main component. Mixing device (1) according to one of the preceding claims, in which the spray device (11) is attached to a wall (15) on the underside of the mixing chamber (2) or partially or completely within a wall (15) below the closing surfaces (2a, 6a ) is arranged. Mixing device (1) according to one of the preceding claims, in which the spray device (11) is arranged between the discharge device (13) and the mixing chamber (2). Mixing device (1) according to one of the preceding claims, having a control device (14) for controlling the spraying device (11), wherein the control device (14) is designed to release the anti-adhesive agent (12) as a function of process steps of the mixing device (1) to control. Mixing device (1) after claim 5 , in which the control device (14) is designed to control the spray device (11) for dispensing the anti-adhesive agent (12) when the mixing chamber (2) is closed. Mixing device (1) according to one of Claims 5 or 6 , in which the control device (14) is designed to control the spray device (14) in such a way that the delivery of the anti-adhesive agent (12) is terminated at the latest when the discharge flap (6) is fully opened. Method for operating a mixing device according to one of the preceding claims, comprising the steps: - Mixing of the material to be mixed (16) in the mixing chamber (2), - Open the discharge flap (6) to empty the mixing chamber (2) so that the material to be mixed (16) can fall down through the discharge flap (6) out of the mixing chamber (2), - Delivery of anti-adhesive agent (12) from the spray device (11) onto the area of the emptying device (13) and/or the mixing chamber (2) below the closing surfaces (2a, 6a). procedure after claim 8 , wherein release of anti-adhesive agent (12) before opening the discharge flap (6) takes place. Procedure according to one of Claims 8 or 9 , in which the dispensing of anti-adhesion agent (12) is terminated before the discharge flap (6) is fully opened.

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