EP3824236B1 - Air lock - Google Patents

Description

The present invention relates to an air lock with a housing that has a front inlet opening, a rear outlet opening and a lock shaft running in between, through which a transport device passes, which is connected to workpiece carriers in such a way that workpieces arranged thereon can be transported through the lock shaft. Such airlocks are closed inlet locks especially for ovens, such as from the GB515121A known and exemplified in 1 shown. The infeed lock 1 shown here is arranged upstream of a furnace 2 in the transport direction 3 and is designed as a closed infeed lock 1 . The inlet sluice 1 has a front opening 4 through which the workpieces are introduced into the sluice shaft 6 with a transport device 5 . In the exemplary embodiment shown, the transport device is designed as a carrier that is pushed into the lock shaft complete with the workpieces arranged on it using the pushing method. The sluice shaft 6 is then closed and the air in it is drawn off, so that a vacuum forms in the sluice shaft 6 . The lock shaft 6 is then opened towards the furnace 2 and the workpieces can be transported into the furnace 2 without the atmosphere prevailing here being contaminated by air, oxygen and/or other gases.

Such closed inlet sluices are disadvantageous because they only allow the workpieces to be transported in a clocked manner and because the complete pumping out of the air in the sluice shaft is time-consuming and costly.

Proceeding from this, it is the object of the present invention to specify an airlock which at least partially eliminates the problems of the prior art. In particular, an airlock should be specified, the one cost-effective and comparatively fast transport of the workpieces through the air lock.

This object is solved by the airlock according to claim 1. According to the invention, it is provided that the transport device is connected at least indirectly (i.e. directly or indirectly) to partitions arranged transversely to the transport direction, which each delimit workpiece chambers to the front and rear, with the lock shaft having at least one first gas inlet opening and at least one first gas outlet opening, which are located within the Lock shaft open into a workpiece chamber, so that an inert gas can be introduced into the workpiece chamber through the gas inlet opening, which flows through the workpiece chamber from the gas inlet opening to the gas outlet opening.

In other words, seen in the direction of transport, the lock shaft is closed by a plurality of partitions arranged one behind the other, between which a workpiece chamber is formed in each case. The workpiece chambers are not delimited laterally, downwards and upwards by separate partition walls, but by the lock shaft itself, in which the at least one gas inlet opening and the at least one gas outlet opening are arranged at suitable points and transverse to the transport direction. As soon as a workpiece chamber is transported past the gas inlet and gas outlet openings during transport through the lock shaft, inert gas flows through the workpiece chamber and the previous gas-air mixture is discharged through the gas outlet opening. When leaving the air lock, the workpiece chambers are then completely filled with inert gas and the atmosphere located behind the lock, for example in a furnace, is not contaminated by gas or air from the outside. As a result, the workpieces arranged in the workpiece chambers can be transported through the lock shaft continuously or in a clocked manner and comparatively quickly and cost-effectively. In addition, the device is easily constructed and easy to maintain, which means that the manufacturing costs are also comparatively low.

Preferred embodiments of the present invention are given below and in the subclaims.

According to a first preferred embodiment of the present invention, it is provided that the lock shaft is delimited laterally by shaft walls and/or downwards by a shaft floor and/or upwards by a fixedly or movably mounted shaft cover. The partitions, which are loosely mounted on the transport device, lie within the lock shaft at least in regions on the shaft walls, shaft floor and shaft ceiling, so that gas exchange between two adjacent workpiece chambers in the transport direction is blocked. The movably mounted manhole cover is preferably suspended from a number of springs, so that the pressure with which the manhole cover rests on the partition walls can be regulated. Increased pressure ensures additional tightness, but care must be taken to avoid the partition walls wearing out quickly as a result of excessive pressure. As an alternative to a spring-loaded manhole cover, the manhole cover can also be freely suspended, so that gravity ensures that the manhole cover rests on the partition walls. This also makes it possible to compensate for wear and tear caused by wear and tear, in particular on the upper side of the partition walls, manufacturing tolerances and/or heat-related distortion. The shaft walls, the shaft floor and/or in particular the shaft ceiling can have a thin silicone seal, which increases the ability to slide and the tightness. Alternatively and/or additionally, the partition walls can have a seal, in particular a silicone seal, partially or completely at the edges.

The at least one gas inlet opening and the at least one gas outlet opening are preferably arranged on the side and opposite one another on the lock shaft. As a result, the inert gas flows through the entire workpiece chamber from the gas inlet opening to the gas outlet opening, so that at most minor residual components of the original atmosphere remain in the workpiece chamber during rapid transport.

Outside the lock shaft, the gas inlet opening and the gas outlet opening are preferably each connected to a flushing channel. The inert gas can be introduced through the scavenging duct on the gas inlet opening side and the gas-air mixture can be discharged at the scavenging duct on the gas outlet opening side and possibly fed to a recycling plant where the inert gas is separated from the other gas components for reuse.

In order to also avoid a slight gas exchange between two adjacent workpiece chambers at the edges of the partition walls, according to a preferred embodiment of the present invention, it is provided that the gas inlet opening and the gas outlet opening have at least twice the width of a workpiece chamber, so that at least two adjacent workpiece chambers can Purged with inert gas, with inert gas flowing through the workpiece chambers in the same direction. Due to the fact that the inert gas has the same flow direction and preferably the same flow rate, there are no eddy formations at the ends and sealing surfaces of the partition walls, which would otherwise cause an undesired gas exchange.

In order to also remove the last remaining components of the original gas within the workpiece chambers, according to a preferred embodiment of the invention, it is provided that the flushing channel opens into the lock shaft several times via a number of gas inlet openings and a number of gas outlet openings. As a result, the flushing process can be carried out several times, so that even the last residual components of foreign gas are removed and replaced by inert gas.

In order to prevent residual gas from accumulating in areas that cannot be reached by the inert gas flow within a workpiece chamber during multiple flushing, for example in flow shadows, it is preferably provided that the gas inlet openings and the gas outlet openings are arranged in such a way that the workpiece chambers are flushed in pairs in alternating directions with inert gas. For example, if the first flushing process takes place from left to right, the subsequent gas inlet and gas outlet openings are arranged in such a way that the flushing process is carried out from right to left, etc. There is a distance between a gas inlet opening and an adjacent gas outlet opening on the same side of the lock shaft of at least one workpiece chamber width, so that an opposing air flow between two adjacent workpiece chambers is avoided, which would otherwise lead to an undesired gas exchange due to turbulence at the partition wall edges.

The present air lock with the transport device allows both a continuous and a cycle-bound transport of the workpieces. The transport device preferably has two chains, each of which runs on a guide. The workpiece carriers can be attached to such chains, which in turn are connected to the partition walls. The partitions are preferably connected to the workpiece carriers with L-shaped profile pieces, which preferably have an elongated hole for fastening the partitions, which allow the partitions to be mounted loosely and within limits movable. As a result, height differences caused by wear and heat-related distortion are automatically compensated.

In order to achieve a clean scavenging result with a proposed air lock, it is preferably provided that at least part of the scavenging gas or the inert gas can be conditioned. After this, the volume flow, the flow speed, the pressure, the temperature, the humidity and/or the particle load of the (inert) gas can be set according to the requirements.

The airlock can be used for any application. According to a preferred embodiment, however, the exit opening of the air lock is connected to an oven. Such a furnace can also be equipped with one at the exit corresponding air lock so that the inert gas contained in the workpiece chambers can be collected and reused.

Depending on the area of application, an inert gas is used that does not lead to any contamination within the application. Nitrogen, carbon dioxide and all noble gases are usually suitable as possible inert gases.

A specific embodiment of the present invention is explained below with reference to the figures.

Fig. 1

einen Ofen mit einer Luftschleuse nach dem Stand der Technik,

Fig. 2 bis 7

unterschiedliche Querschnittsansichten einer Luftschleuse und

Fig. 8

eine perspektivische Darstellung einer Luftschleuse.

Show it:

1

a prior art furnace with an airlock,

Figures 2 to 7

different cross-sectional views of an airlock and

8

a perspective view of an airlock.

2 shows the simplest embodiment of an air lock 10 according to the invention, which has a housing 11 with a front inlet opening 12 and a rear outlet opening 13 . In between, the lock shaft 14 is formed, through which a transport device 15 passes. The transport device 15 is connected to workpiece carriers 16 on which workpieces 17 can be arranged. In the present exemplary embodiment, the workpiece carrier 16 is a blade holder, on which various blades are lined up as workpieces 17, which are placed in a furnace downstream of the air lock 10 (in 2 not shown) are supplied. Furthermore, dividing walls 18 which are aligned transversely to the transport direction 3 and close the lock shaft 14 in the transport direction 3 are fastened on the transport device 15 . A workpiece chamber 19 is formed between each of two partition walls 18 and is delimited to the front and rear within the air lock 10 by the partition walls 18 and otherwise by the lock shaft 14 .

The lock shaft 14 has a lateral gas inlet opening 20 and _a gas outlet opening 21 opposite. In the workpiece chamber _19b that is transported further, there is at best only inert gas, so that the workpiece 17 can be released at the outlet opening 13 without contamination of the atmosphere.

In order to increase the degree of gas exchange within the workpiece chambers 19, it is preferably provided that the gas inlet opening 20 and the gas outlet opening 21 are at least twice as wide as a workpiece chamber 19, so that two workpiece chambers 19 arranged next to one another are flushed with inert gas at the same time, with the Inert gas flows through both workpiece chambers 19 in the same direction.

3 shows a further preferred embodiment of the invention, in which the air lock 10 has a plurality of gas inlet openings 20 and a plurality of gas outlet openings 21, which are each connected to a flushing channel 24 outside of the lock shaft 14, through which the inert gas or the inert gas-gas mixture can flow multiple times and in different directions flows through the workpiece chambers 19. This prevents gas from accumulating in any flow shadows, so that a complete gas exchange takes place. Furthermore, all gas inlet openings 21 and all gas outlet openings 22 have twice the width of a workpiece chamber 19, so that two adjacent workpiece chambers 19 are flushed with inert gas at the same time and in the same direction. The flow directions of the inert gas are in 3 marked with the arrows 25 which also pass through the arcuate scavenging channels 24 connecting a gas inlet port 21 to an adjacent gas outlet port 20 on the same side of the housing 11 respectively. A distance of at least one workpiece chamber width is provided between them, so that turbulence caused by the flow at the partitions 18 is avoided.

In the illustrated embodiment, the scavenging channels 24 have wall sections 32 arranged in the center, so that each side of the scavenging channel 24 has the width of a workpiece chamber 19 . This results in a uniform flushing of two adjacent workpiece chambers 19 because no pressure differences build up and the inert gas flows in both workpiece chambers 19 at the same speed.

with the inside 3 illustrated embodiment of the present invention, the rinsing processes are connected quasi "in series" and the flow of inert gas is directed in the opposite direction to the transport direction 3 of the workpieces 17 . This means that each workpiece chamber 19 is first flushed with a mixture of inert gas and gas from the original atmosphere during transport through the lock shaft 14 because the mixture has already flowed through several other workpiece chambers 19 and has absorbed gas from the original atmosphere there. Irrespective of the number of rinsing processes provided, in the present embodiment there is a rinsing process with pure inert gas only during the last rinsing process, because there the inert gas is introduced directly from the source into the workpiece chambers 19 .

As an alternative to such a "series connection" of the rinsing processes, a "parallel connection" is also provided, in which the workpiece chambers 19 are directly connected to an inert gas source and each rinsing process is carried out with pure inert gas. Here, too, an alternating flushing direction is advantageous and is therefore provided. The workpiece chambers 19 can each be connected to its own inert gas source or a common inert gas source with suitable supply lines can be used.

4 shows a cross-sectional view of a portion of the airlock 10 (see cross-section XX from 3 ). In this exemplary embodiment, the transport device 15 is designed as a chain 26 which runs on a guide 27 . Workpiece carriers 16 are mounted on the chain 26, which carry the workpieces 17 (here hold razor blades). Furthermore, the workpiece carriers 16 are connected to the dividing walls 18 via L-shaped profile pieces 28 in such a way that the dividing walls 18 bear against the shaft base 29 and the shaft ceiling 30 . This prevents gas exchange between two adjacent workpiece chambers 19 in the transport direction 3 . The flow of the inert gas or the inert gas-gas mixture is in 4 represented by the circled dots and the circled crosses, respectively. In the two right-hand workpiece chambers 19, the gas flow points into the plane of the page, and in the two left-hand workpiece chambers 19, the gas flow points out of the plane of the page. In the workpiece chamber 19 arranged between them, there is no gas flow due to the gas inlet and gas outlet openings 20, 21 being spaced apart from one another.

figure 5 shows a further cross-sectional view of the airlock 10 seen in the transport direction 3, which points in the plane of the page (see cross-section YY from 4 ). Here it can be seen that the partition walls 18 are in contact with the lock shaft 14 on all sides, so that a gas exchange in the transport direction 3 is avoided.

the 6 and 7 correspond to the cross-sectional views of FIG 4 and 5 , A movably mounted manhole cover 30 being provided in the exemplary embodiments shown. For this purpose, the shaft cover 30 is suspended on springs 31 in the lock shaft 14 so that the shaft cover 30 rests on the partition walls 18 with an adjustable pressure. In this way, differences in height of the partition walls 18 caused by wear can be compensated for.

Finally shows 8 a perspective view of a specific embodiment of the air lock 10 according to the invention, which is upstream of a furnace 2, so that there is a constant and oxygen-free atmosphere in the furnace 2.

Reference List

1

inlet lock

2

oven

3

transport direction

4

front opening

5

transport device

6

lock shaft

10

airlock

11

Housing

12

front intake port

13

rear exit opening

14

lock shaft

15

transport device

16

workpiece carrier

17

workpiece

18

partition wall

19

workpiece chamber

20

gas inlet port

21

gas outlet port

22

arrow direction

23

arrow direction

24

flushing channel

25

arrow direction

26

Chain

27

guide

28

profile piece

29

shaft bottom

30

manhole cover

31

feathers

32

wall sections

Claims (13)

1. Airlock with a housing (11) which has a front inlet opening (12), a rear outlet opening (13) and an airlock shaft (14) extending therebetween, which is passed through by a transport device (15), which is connected to workpiece carriers (16) such that workpieces (17) arranged thereon can be transported through the airlock shaft (14), wherein

   - the transport device (15) is at least indirectly connected to partition walls (18) arranged transversely to the direction of transport (3), the partition walls (18) each delimiting workpiece chambers (19) to the front and rear,

   characterized in that

   - the airlock shaft (14) has at least one first gas inlet opening (20) and at least one first gas outlet opening (21), which open into a workpiece chamber (19) within the airlock shaft (14), so that an inert gas can be introduced into the workpiece chamber (19) through the gas inlet opening (20), the inert gas flowing through the workpiece chamber (19) from the gas inlet opening (20) to the gas outlet opening (21).
2. Airlock according to one of the preceding claims, wherein the airlock shaft (14) is delimited

   - laterally by shaft walls and/or

   - downwardly by a shaft floor (29) and/or

   - upwardly by a fixed or movably mounted shaft ceiling (30).
3. Airlock according to claim 2, wherein the partition walls (18) within the airlock shaft (14) abut the shaft walls, the shaft floor (29), and the shaft ceiling (30) at least in some regions, so that a gas exchange between two workpiece chambers (19) is blocked in the direction of transport (3).
4. Airlock according to claim 1, wherein the gas inlet opening (20) and the gas outlet opening (21) are arranged laterally and oppositely on the airlock shaft (14).
5. Airlock according to one of the preceding claims, wherein the gas inlet opening (20) and the gas outlet opening (21) are each connected to a flushing channel (24) outside the airlock shaft (14).
6. Airlock according to one of the preceding claims, wherein the gas inlet opening (20) and the gas outlet opening (21) have at least twice the width of one workpiece chamber (19), so that in each case at least two adjacent workpiece chambers (19) are flushed simultaneously with inert gas which flows through the workpiece chambers (19) in the same direction.
7. Airlock according to one of the preceding claims, wherein the flushing channel (24) opens into the airlock shaft (14) plurally via a plurality of gas inlet openings (20) and a plurality of gas outlet openings (21).
8. Airlock according to claim 7, wherein the gas inlet openings (20) and the gas outlet openings (21) are arranged such that the workpiece chambers (19) are flushed with inert gas in pairs in alternating directions.
9. Airlock according to one of the preceding claims, wherein there is a distance of at least one workpiece chamber width between a gas inlet opening (20) and an adjacent gas outlet opening (21) on the same side of the airlock shaft (14).
10. Airlock according to one of the preceding claims, wherein the transport device (5) allows continuous or cycle-dependent transport of the workpieces (17).
11. Airlock according to one of the preceding claims, wherein the transport device (5) has at least two chains (26), each of which runs on a guide (27).
12. Airlock according to one of the preceding claims, wherein the workpiece carriers (16) are connected to the chains (26) and the partition walls (18).
13. Airlock according to one of the preceding claims, wherein the outlet opening (13) of the airlock (10) merges into an oven (2).

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