EP3686430B1 - System and method for evacuating a process room - Google Patents

Description

The invention relates to a system for evacuating a process space. The invention also relates to a method for evacuating a process space.

A large number of applications in which a process space has to be evacuated are known from practice. To date, vacuum pumps have been used for this purpose. If vacuum pumps are used to evacuate a process room, this can take too long in process rooms that have a large volume to be evacuated. There is therefore a need for a novel system and method for evacuating a process space, with the aid of which, in particular, large process spaces can be reliably evacuated within a short time.

An example of a system for evacuating a process room is the document JP 2015 102036 , after which two vacuum pumps are used, which can be operated in series or in parallel.

Proceeding from this, the present invention is based on the object of creating a novel system and method for evacuating a process space.

This object is achieved by a system for evacuating a process space according to claim 1.

The system according to the invention for evacuating a process space has a first compressor which can be coupled to the process space via a first supply line and from which medium removed from the process space can be discharged into the environment via a first drainage line.

The system according to the invention for evacuating a process space also has a second compressor which can be coupled to the process space via a second inlet line and from which medium removed from the process space can be discharged into the environment via a second drain line.

The system according to the invention for evacuating a process space also has a connecting line connected between the first drain line and the second feed line.

A first inlet line valve is integrated into the first inlet line. A second inlet line valve is integrated into the second inlet line. A drain line valve is integrated into the first drain line. A connection line valve is integrated in the connection line.

Then, when the first inlet line valve, the second inlet line valve and the first outlet line valve are all open and the connecting line valve is closed, the first compressor and the second compressor can be operated in parallel. Then, when the first inlet line valve and the connecting line valve are both open and the second inlet line valve and the first outlet line valve are both closed, the first compressor and the second compressor can be operated in series.

The system according to the invention for evacuating a process space does not use vacuum pumps, but rather compressors. The first compressor and the second compressor form a compressor group, and the two compressors can be operated in parallel as well as in series. The compressors are operated in parallel above a pressure limit. When the pressure limit value is reached or not reached, the compressors are operated in series. This allows a relatively large process space to be evacuated to a high negative pressure within a short time.

According to an advantageous development, a first external air line valve is integrated into a first external air line leading to the first compressor, a second external air line valve being integrated into a second external air line leading to the second compressor, and the first external air line valve and the second external air line valve depending on the operating conditions of the first compressor and the second compressor are controllable. The external air line valves can be activated depending on the operating conditions of the compressors in order to ensure safe operation of the compressors.

According to an advantageous development, the first feed line valve and the second feed line valve can be controlled as a function of the operating conditions of the first compressor and the second compressor. The activation of the two inlet line valves depending on the operating conditions of the two compressors serves to protect electrical machines that are used to drive the compressors.

According to an advantageous development, a first pressure sensor is assigned to the first inlet line, a second pressure sensor being assigned to the second inlet line, and the second inlet line valve, the first outlet line valve and the connecting line valve all being controllable as a function of measured values from the two pressure sensors. The pressure sensors can be used to easily and reliably monitor the negative pressure up to which the process space to be evacuated was evacuated. Depending on the measured values of the pressure sensors, it is then possible to switch from parallel operation of the compressors to serial operation of the compressors, for which purpose the valves are then controlled accordingly.

The method according to the invention for evacuating a process space is defined in claim 5.

Fig. 1:

ein Blockschaltbild eines erfindungsgemäßen Systems zum Evakuieren eines Prozessraums in einem ersten Betriebszustand,

Fig. 2

das System der Fig. 1 in einem zweiten Betriebszustand.

Preferred developments of the invention emerge from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being restricted thereto. It shows:

Fig. 1:

a block diagram of a system according to the invention for evacuating a process room in a first operating state,

Fig. 2

the system of Fig. 1 in a second operating state.

The invention relates to a system and a method for evacuating a process space, in particular a process space with a large volume.

A large-volume process space should be understood to mean a process space whose volume to be evacuated is in the order of magnitude of more than 10,000 m ³ , in particular more than 20,000 m ³ .

Figs. 1 and 2 each show a schematic block diagram of a system 10 for evacuating a process room 11 in two different operating states.

The system 10 for evacuating the process space 11 has a first compressor 12 and a second compressor 13.

The first compressor 12 is driven by an electric machine 14, which transmits drive power to the first compressor 12 via a transmission 15. The second compressor 13 is also driven by an electric machine 16, which transmits drive power to the second compressor 13 via a transmission 17.

The first compressor 12 can be coupled to the process space 11 via a first feed line 18. The second compressor 13 can be coupled to the process space 11 via a second feed line 19. Medium removed from the process space 11 can be discharged from the first compressor 12 via a first discharge line 20 into the environment. Starting from the second compressor 13, the medium removed from the process space 11 can be discharged into the environment via a second discharge line 21.

A connecting line 22 is connected between the first discharge line 20, which leads from the first compressor 12 into the environment, and the second inlet line 19, which leads from the process space 11 in the direction of the second compressor 13. Via this connecting line 22, medium can be conducted starting from the first compressor 12 in the direction of the second compressor 13.

A first feed line valve 23 is integrated into the first feed line 18. A second feed line valve 24 is integrated into the second feed line 19.

A first drain line valve 25 is integrated into the first drain line 20, namely downstream of the branch of the connecting line 22 from the first drain line 20. A connecting line valve 26 is integrated into the connecting line 22. Although in Figs. 1 and 2 Not shown, provision can also be made to integrate a drain line valve into the second drain line 21, which would then be referred to as a second drain line valve.

As already stated, the connecting line 22 branches off from the first drain line 20 upstream of the first drain line valve 25 and opens downstream of the second supply line valve 24 into the second supply line 19 upstream of the second compressor 13.

Fig. 1 shows a state of the system 10 in which the two compressors 12, 13 are operated in parallel. In this case, the first inlet line valve 23, the second inlet line valve 24 and the first outlet line valve 25 are all open, whereas the connecting line valve 26 is closed.

Fig. 2 shows a state of the system 10 in which the two compressors 12 and 13 are operated in series. In this state, the first feed line valve 23 and the connecting line valve 26 are both open. The first drain line valve 25 and the second supply line valve 24 are both closed.

According to Figs. 1 and 2 the system 10 comprises a first external air line 27 leading to the first compressor 12, in which a first external air line valve 28 is integrated. A second external air line 29, into which a second external air line valve 30 is integrated, leads to the second compressor 13. The two external air line valves 28 and 30 can be controlled as a function of the operating conditions of the two compressors 12 and 13. The two inlet line valves 23 and 24 can also be controlled as a function of the operating conditions of the two compressors 12 and 13.

The system for evacuating a process room also has pressure sensors. A first pressure sensor 31 is assigned to the first feed line 18 and a second pressure sensor 32 is assigned to the second feed line 19. The pressure that prevails in the first feed line 18 leading to the first compressor 12 can be determined via the first pressure sensor 31. The pressure that prevails in the second feed line 19 leading to the second compressor 13 can be determined via the second pressure sensor 32. The second inlet line valve 24, the first outlet line valve 25 and the connecting line valve 26 can be controlled as a function of the measured values of the two pressure sensors 31 and 32.

To evacuate the process space 11, both compressors 12, 13 are initially operated in parallel up to a pressure limit value. In parallel operation of the two compressors 12, 13 they provide a large suction volume or delivery volume, this parallel operation being maintained during evacuation as long as the pressure in at least one of the two inlet lines 18, 19 is greater than the pressure limit value.

When the pressure limit value is reached or undershot, the evacuation of the process space 11 also takes place using both compressors 12, 13, which are then no longer operated in parallel but in series, that is to say in series operation. In this case, although the delivery volume is lower, an even greater evacuation of the process space 11 is possible down to a pressure which is below the pressure limit value.

The method for evacuating the process space 11 is carried out using the system described above. Then, when both compressors 12, 13 are operated in parallel, the first inlet line valve 23, the second inlet line valve 24 and the first outlet line valve 25 are all opened, whereas the connecting line valve 26 is closed. Then, when the two compressors 12, 13 are operated in series, the first inlet line valve 23 and the connecting line valve 26 are both opened, whereas the second inlet line valve 24 and the first outlet line valve 25 are both closed.

It is then preferably of the parallel operation of the two compressors 12, 13 according to FIG Fig. 1 changed or switched to the serial operation of the two compressors 12, 13 according to FIG. 3 when the first pressure sensor 31 and the second pressure sensor 32 each deliver a pressure measurement value that is less than or equal to the pressure limit value.

Then if, as in Fig. 2 As shown, both compressors 12, 13 are operated in series, the external air line valve 30 integrated in the second external air line 29 is preferably opened in order to mix the medium already passed through the first compressor 12 with external air upstream of the second compressor 13. As a result, the second compressor 13 can then be operated at an optimal operating point, on the one hand to lead a sufficiently high flow rate via the second compressor 13 and on the other hand to keep the temperature of the medium carried via the second compressor 13 below a temperature limit value.

Preferably, in serial operation of the two compressors 12, 13, the second external air line valve 30 is opened to such an extent that a ratio V = F ₂₂ / F ₂₉ between the delivery flow F ₂₂ in the connecting line 22 downstream of the compressor 12 and that via the external air line 29 downstream of the external air line valve 30 guided _{flow rate F 29, the} following applies: 0.9≤V≤2.0. The following preferably applies: 1.0 V 1.7. Particularly preferably, V = 1.0 applies.

To provide compressor protection for the compressors 12, 13, it is possible for the external air line valves 28 and 30 to be activated depending on the power consumption of the electrical machine 14, 16 driving the respective compressor 12, 13.

For example, if the electrical power consumption of the electrical machine 14 driving the first compressor 12 is too low and less than the corresponding limit value, the external air line valve 28 is preferably opened to protect the compressor in order to always lead a sufficiently large delivery rate via the compressor 12. Similarly, when the power consumption of the second electrical machine 16 driving the second compressor 13 is less than a corresponding limit value, the external air line valve 30 is opened in order to always lead a sufficiently large amount of air via the second compressor 13.

Furthermore, in order to protect the motor of the electrical machine 13, 14 driving the respective compressor 12, 13, the feed line valves 23, 24 can be controlled depending on the power consumption of the compressors 12, 13.

If, for example, the power consumption of the electrical machine 14 driving the first compressor 12 is too great, that is to say greater than a corresponding limit value, the first inlet line valve 23 can be closed more strongly in order to provide motor protection for the electrical machine 14. In an analogous manner, if the power consumption of the second electrical machine 16 driving the second compressor 13 is too great, the second feed line valve 24 can be closed more strongly in order to provide motor protection for the electrical machine 16 of the second compressor 13.

The compressor protection and the motor protection are advantageous in order to avoid damage to the compressors 12, 13 and the electrical machines 14, 16 during evacuation operation.

As already stated, the process space 11 is initially evacuated up to a pressure limit value in parallel operation of the two compressors 12, 13 (see FIG Fig. 1 ). When the pressure limit value is reached or not reached, the parallel operation of the compressors 12, 13 switches to serial operation of the compressors 12, 13 (see Fig. 2 ) changed in order to enable an even greater evacuation of the process space 12.

The two compressors 12, 13 can be radial compressors.

For this purpose, it is possible, for example, to use radial compressors that can provide ^{a flow rate of 1400 m 3 / min.}

When the two compressors 12, 13 are operated in parallel, a total delivery rate of 2800 m ³ / min can then be evacuated from the process space 11 by them. This is preferably done until a pressure limit value is reached, which is, for example, -63 kPa.

When the pressure falls below this limit value of -63 kPa, the two compressors are switched from parallel operation to serial operation in order, for example, to evacuate the process space 11 to a pressure of -85 kPa. In serial operation, of course, a smaller delivery rate is available than in parallel operation.

It should be noted that the above numerical examples are only used for illustration and are purely exemplary in nature.

The system according to the invention and the method according to the invention are preferably used for evacuating relatively large process spaces 11 with a volume of more than 10,000 m ³ , in particular more than 20,000 m ³ . Such process spaces can be, for example, transport tubes with a diameter of more than 2 m and a length of more than 1 km.

As already stated, the two compressors 11, 12 form a compressor group. There can be several such compressor groups and each compressor group can be operated in the manner described above.

List of reference symbols

10

system

11

Process space

12th

compressor

13th

compressor

14th

electric machine

15th

transmission

16

electric machine

17th

transmission

18th

Feed line

19th

Feed line

20th

Drain line

21st

Drain line

22nd

Connecting line

23

Inlet line valve

24

Inlet line valve

25th

Drain line valve

26th

Connecting line valve

27

External air line

28

External air line valve

29

External air line

30th

External air line valve

31

Pressure sensor

32

Pressure sensor

Claims (7)

1. A system (10) for evacuating a process space (11),
   having a first compressor (12), which can be coupled via a first inflow line (18) to the process space (11) and from which, via a first outflow line (20), medium taken from the process space (11) can be discharged into the surroundings,
   having a second compressor (13), which via a second inflow line (19) can be coupled to the process space (11) and from which, via a second outflow line (21), medium taken from the process space (11) can be discharged into the surroundings,
   having a connecting line (22) connected between the first outflow line (20) and the second inflow line (10),
   having a first inflow line valve (23) integrated in the first inflow line (18),
   having a second inflow line valve (24) integrated in the second inflow line (19),
   having a first outflow line valve (25) integrated in the first outflow line (20),
   having a connecting line valve (26) integrated in the connecting line (22),
   wherein in particular when the first inflow line valve (23), the second inflow line valve (24) and the first outflow line valve (25) are all open and the connecting line valve (26) is closed, the first compressor (12) and the second compressor (13) can be operated in parallel,
   wherein in particular when the first inflow line valve (23) and the connecting line valve (26) are both open and the second inflow line valve (24) and the first outflow line valve (25) are both closed, the first compressor (12) and the second compressor (13) can be operated in series, characterized in that
   the first inflow line (18) is assigned a first pressure sensor (31) and the second inflow line (19) a second pressure sensor (32),
   wherein the second inflow line valve (24), the first outflow line valve (25) and the connecting line valve (26) can all be controlled dependent on measurement values of the two pressure sensors (31, 32).
2. The system according to Claim 1, characterized by
   a first external air line (27) leading to the first compressor (12), in which a first external air line valve (28) is integrated,
   a second external air line (29) leading to the second compressor (13), in which a second external air line valve (30) is integrated,
   wherein the first external air line valve (28) and the second external air line valve (30) can be controlled dependent on operating conditions of the first compressor (12) and of the second compressor (13).
3. The system according to Claim 1 or 2, characterized in that the first inflow line valve (23) and the second inflow line valve (24) can be controlled dependent on operating conditions of the first compressor (12) and of the second compressor (13).
4. A method for evacuating a process space (11),
   wherein the process space (11) is evacuated initially up to a pressure limit value using two compressors (12, 13) operated in parallel,
   wherein subsequently the process space (11) is evacuated after the pressure limit value has been reached or undershot, using the two compressors (12, 13) now operated in series, wherein the same is carried out using a system according to any one of the Claims 1 to 3,
   wherein in particular when the two compressors (12, 13) are operated in parallel, the first inflow line valve (23), the second inflow line valve (24) and the first outflow line valve (25) are all open and the connecting line valve (26) is closed,
   wherein in particular when the two compressors (12, 13) are operated in series, the first inflow line valve (23) and the connecting line valve (26) are both open and the second inflow line valve (24) and the first outflow line valve (25) are both closed,
   characterized in that the parallel operation of the two compressors (12, 13) is changed to the series operation of the two compressors (12, 13), in particular when the first pressure sensor (31) and the second pressure sensor (32) both supply a pressure measurement value each that is smaller or equal to the pressure limit value.
5. The method according to Claim 4, characterized in that in particular when the two compressors (12, 13) are operated in series, the second external air line valve (30) is opened in order to mix the medium already conducted via the first compressor (12) with external air upstream of the second compressor (13).
6. The method according to Claim 5, characterized in that the second external air line valve (30) is opened so far that a ratio between the flow rate in the connecting line (22) downstream of the first compressor (12) and the flow rate in the external air line (29) downstream of the external air line valve (30) is between 0.9 and 2.0.
7. The method according to any one of the Claims 4 to 6, characterized in that
   for the compressor protection of the compressors (12, 13), dependent on the power consumption of an electric machine (14, 16) driving the respective compressor (12, 13), an external air line valve (28, 30) interacting with the respective compressor (12, 13) is controlled, and/or
   for the motor protection of the electric machine (14, 16) driving the respective compressor (12, 13), depending on the power consumption of the electric machine (14, 16) driving the respective compressor (12, 13), an inflow line valve (23, 24) interacting with the respective compressor (12, 13) is controlled.

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