Field of the invention

The invention relates to closures of bulk material locks. The invention is intended to avoid disruption of the closing process and damage to the closure by bulk material getting between the closure seat and the closing body. In particular, the invention is in- tended to counteract excessive wear on the sealing surfaces.

Prior art

Closures for bulk material locks often comprise a seat having a circular opening rim and a disc-shaped closing body having a chamfered closing surface, wherein the opening rim and the base surface of the closing body are arranged horizontally. Furthermore, they comprise a mechanism which holds the closing body and can move it in a vertical direction, wherein the closing body is connected to the mechanism by a rod, chain or cable. By means of this mechanism, the closing body can close the opening of the bulk material lock. In this case, the chamfered closing surface thereof is pressed against the opening rim. Bulk material locks having closures of this kind are often used to charge fixed-bed pressure gasification reactors, in which a solid, carbon-containing fuel, such as coal or coke, is gasified, using oxygen and steam, to form a synthetic gas consisting primarily of carbon monoxide and hydrogen. For further details of the process, attention is drawn to the relevant literature, cf. U!lmanns Encyclopedia of Industrial Chemistry, Sixth Edition, Vol. 15, page 367 ff.

One example of a closure corresponding to the field of the invention is shown in US application 2014/0191151 A1.

However, another type of closure is also employed for the same purpose, i.e. for closing bulk material locks, one example thereof being shown in German Laid-Open Application DE 40 41 445 A1. One significant difference between these two types of embodiment consists in the shape of the closing body. In the first case, this has the shape of a disc, the upper edge of which is chamfered to form an oblique closing surface.

In the second type of embodiment, the closing body is conical. This shape ensures that the lumps of fuel falling via the closing body as the lock is filled are not retained on the upper side of the closing body. This prevents lumps of fuel being deposited on the closing body, which could fall off due to shocks when the closure is closed and get between the seating edge and the closing surface of the closing body. However, embodying the closing body as a cone is more complex in terms of design and more expensive.

In contrast, the formation of fuel deposits in the case of a disc-shaped closing body cannot be excluded since the upper side thereof is flat. With this type of closing body, there is therefore the risk that lumps of fuel will get between the closure seat and the closing surface during the closing process and that there will be damage during this process, preventing gas-tight closure and thus leading to stoppages for repair of the gasification plant. It is the object of the invention to propose a device with which a closure having a discshaped closing body can be modified in such a way that the disadvantages described are avoided. Description of the invention

The object is achieved by a device according to Claim 1.

Device according to the invention:

Hood for covering the upper side of a disc-shaped closing body of a closure of a bulk material Sock against deposits of bulk material, wherein the hood is conical and wherein the base surface of the hood has the same size as the upper side of the closing body.

Covering the flat upper side of the disc-shaped closing body with a hood according to the invention prevents the deposition of lumps of fuel on the closing body. The hood covers the flat locations of the upper side of the closing body and the fastening elements, rod or chain, which are present on the upper side of the closing body and by means of which the closing body is held and moved. Already existing bulk material locks can be retrofitted in a simple manner with the hood according to the invention, thus reducing problems with sealing caused by unwanted deposits of bulk material on the flat surface of the disk-shaped closing body.

It is advantageous that the hood can be manufactured from thin-walled material since it has merely to deflect the falling bulk material but does not absorb any mechanical forces caused by the pressing of the closing body into the seat of the closure. These are ab- sorbed exclusively by the closing body.

Preferred embodiments of the invention

A preferred embodiment of the invention is characterized in that it is composed of an upper, conical, frustoconical or hemi-spherical part and a lower, cylindrical or frustoconi- cal part. In this way, the shape of the hood can be matched to the respective space conditions without the formation on the hood surface of faces or edges on which deposits could occur. Another preferred embodiment of the invention is characterized in that the hood is configured in such a way that the angle formed between the cone lateral surface thereof and the flat surface of the closing body is greater than or equal to the tipping angle of the bulk material tipped into the bulk material lock. This ensures that the slope of the cone or the hood lateral surface is large enough for lumps of bulk material to slip off. The bulk material angle must be determined experimentally for each bulk material in accordance with standard methods known to a person skilled in the art. Furthermore, the invention comprises a closure for a bulk material lock, comprising a seat having a circular opening rim and a disc-shaped closing body having a chamfered closing surface, wherein the upper side of the closing body is covered by means of a hood according to the invention. Moreover, the invention also relates to a bulk material lock for a fixed-bed pressure gasification reactor, which is equipped with a closure according to the invention.

Finally, the invention also relates to a method for retrofitting a closure of a bulk material lock, equipped with a disc-shaped closing body having a flat surface, which is character- ized in that the disc-shaped closing body having a flat surface is provided with a hood according to the invention. In this way, already existing bulk material locks can be retrofitted, thus reducing problems with sealing caused by unwanted deposits of bulk material on the flat surface of the disk-shaped closing body. Illustrative embodiments

Developments, advantages and possible uses of the invention will also become apparent from the following description of non-restrictive illustrative embodiments and from the drawings. Here, all the features described and/or depicted in themselves or in any combination form the invention, irrespective of the grouping thereof in the claims or the dependency references thereof.

The invention will be explained below by means of the drawings, in which: Fig. 1 shows a longitudinal section through a closing body according to the invention having a conical hood,

Fig. 2 shows a longitudinal section through a closing body according to the invention having a hood which comprises a conical upper part and a cylindrical lower part,

Fig. 3 shows a longitudinal section through a closing body according to the invention having a hood which comprises a conical upper and lower part with different slope angles of the lateral surface relative to the base surface.

Fig. 1 shows a disc-shaped closing body 1 having a chamfered closing surface 2 and a flat upper side 3. The closing body 1 is connected to a rod 4, by means of which it is held and moved in a vertical direction. The hood 5 completely covers the flat upper side 3 of the closing body 1 , ensuring that no bulk material deposits can form there. The lat- eral surface 6 of the hood 5 forms the angle 7 with the flat upper side 3 of the closing body 1.

Fig. 2 shows a closing body according to Fig. 1 , but equipped with a hood which comprises an upper, conical part 6 and a lower, cylindrical part 8.

Fig. 3 shows a closing body according to Fig. 1 , but equipped with a hood which comprises a conical upper part 6 and lower part 9 with different slope angles of the respective lateral surface relative to the base surface. Industrial applicability

The invention protects the closure of bulk material locks from damage due to trapped bulk material. This increases the service life of the closure and reduces the frequency of stoppages for repairs. The invention thus increases the economy of the reactor and production process associated therewith. The invention can therefore be applied to advan- tage industrially. List of reference signs

1 closing body

2 chamfered closing surface

3 flat upper side of the closing body

4 rod

5 hood

6 lateral surface

7 angle

8 cylindrical part of the hood

9 lower, conical part of the hood