JP6775527B2 - Vacuum pump system - Google Patents

Description

The present invention relates to a vacuum pump system for discharging the contents in a chamber, particularly a processing chamber or a lock chamber.

Prior art is known for vacuum pump systems for periodically ejecting the contents of large chambers. See FIG. Vacuum pumps that operate dry and compress are often used for this purpose. In general, a vacuum pump is composed of a combination of a backing pump such as a screw pump, a claw pump or a multistage roots pump and a roots pump connected in parallel. In a large pump system, a plurality of pumps and a plurality of roots pumps are connected in parallel.

Typically, such pump systems are used in lock chambers, such as load locks or unload locks, such as coating plants. In such plants, the contents in the chamber must be delivered in a short time, from atmospheric pressure to a transfer pressure of typically about 0.1 mbar to 10 mbar, with a delivery time of, for example, 20 to 120 seconds. The vacuum pump is then separated from the chamber for discharging the contents by a valve on the inlet side and operates at a discharge pressure operation for a certain period of time, typically 1 to 10 times the delivery time.

A more typical application is a large processing chamber for heat treatment or purification of metals. In this case, the typical delivery time is 2 to 30 minutes. After that, a low gas flow must be continued to be delivered, which is much smaller than the gas flow required to achieve the delivery time. The typical holding time for this working pressure is 2-10 times the delivery time.

In such applications, the vacuum pump system must be fairly large to achieve short delivery times. However, during pauses and / or retention times, the pump system's large suction capacity is not required. Therefore, unnecessarily high energy consumption of the pump is required during downtime and / or retention time.

Various techniques are known to reduce the high power consumption of the pump system during downtime and / or retention time.

Temporarily shut down parts of the pump system with backing pumps and / or roots pumps. In this case, there is a disadvantage that the pump cools and adversely affects the service life of the components. In addition, the linings may stick together and interfere with the rotor. During short pauses and / or holding times, the pump must be accelerated again frequently, which requires additional power and a very large motor. Therefore, stopping the pump is not a common practice.

Further, prior art is known to have an additional small auxiliary pump connected in series on the outlet side of each backing pump. See FIG. Such a pump may be, for example, an ejector pump or another smaller backing pump. To avoid too high pressure between the backing pump and the auxiliary pump during delivery time, a switching valve or check valve with a suitable cross section should usually be placed in parallel with the auxiliary pump. Such a solution is disadvantageous due to the large number of additional pumps. Moreover, very small auxiliary pumps, such as ejector pumps, cannot reduce the outlet pressure of the backing pump quickly enough to obtain adequate power savings during short pauses and / or holding times. In addition, auxiliary pumps require energy to operate.

In another solution known in the prior art, a small number of larger backing pumps may be arranged as larger auxiliary pumps on the outlet side of the backing pump. See FIG. These backing pumps are connected in series with the backing pumps via a pipeline system. Again, at least one valve with a suitable cross section must normally be placed in parallel with the auxiliary pump to avoid high pressure between the backing pump and the auxiliary pump during delivery time. This solution is disadvantageous due to the additional purchase and operating costs and the space required for the auxiliary pump.

It is an object of the present invention to provide an improved pump system that reduces power consumption, especially during downtime and retention time.

This objective is achieved by a pump system with multiple vacuum pumps connected in parallel to each other and each connected to a chamber on each inlet side. See FIG. The pump system further comprises an outlet line connected to the outlet side of the vacuum pump. Further, the pump system includes an intermediate line connecting at least one inlet side of the vacuum pump to the outlet side. During the delivery time, all vacuum pumps are connected in parallel, and during the downtime and / or holding time, at least one of the vacuum pumps is connected in series with the other vacuum pump as a backing pump.

Sufficient suction capacity is available for the delivery process because all the vacuum pumps in the pump system are connected in parallel during the delivery time. The vacuum pump system further includes switching means on both the inlet side connection to the chamber and the intermediate line. Such switching means may have, for example, a valve. Thus, during pauses and / or holding times, one of the vacuum pumps may be connected in series with the other vacuum pump as a backing pump. Such a configuration is realized by the switching means correspondingly arranging the switching means to fix or release the connection so that the vacuum pumps are connected in series or in parallel with each other in various ways. Therefore, the outlet pressure of the vacuum pump drops rapidly, and the power consumption is significantly reduced. However, the pump continues to operate for use in the next delivery cycle without any loss of time.

Therefore, because it is not necessary to stop a pump, the pump remains warm and remains fully operational. Another advantage comes from the fact that the drive unit does not need to be configured for frequent acceleration and does not require an additional pump. The additional expenditure for the pump system according to the present invention is limited only to the modification of relatively small pipelines and switching means, such as valves and pump controls.

The pump operates relatively cold so that the reduced energy consumption of the pump system significantly extends the useful life of power electronics in normal wear areas such as oil, bearings, seals and drives. .. In addition, this reduction in energy consumption due to the reduction in waste heat reduces the cost of air conditioning and pump cooling at the installation site. By reducing the pressure at the outlet during operation, condensation of steam in the pump is also prevented, which can reduce damage caused by corrosion.

Very low discharge and / or working pressures can be reached if at least one vacuum pump can be connected in series as a backing pump.

Therefore, a particular processing step may be possible without any additional pumps. For example, leak detection usually requires low working pressure, thus enabling leak detection in the plant before the actual processing operation. During the downtime and / or retention time realized by the present invention, most of the noise emission of the pump is further reduced with reduced load, thus reducing the noise level of the pump system.

The pump system according to the present invention allows for high redundancy, as processing can continue in the event of failure of individual pumps in such a group. Therefore, all pumps can complete their tasks without any auxiliary pumps. In addition, multiple pumps may be incorporated so that they can be used as auxiliary pumps. In addition to reducing power consumption and thus operating costs, CO ₂ emissions for such applications according to the present invention are reduced.

For the operation according to the present invention, it is particularly preferable that a vacuum pump connected in series as a backing pump meets certain technical requirements. It is particularly preferred that these vacuum pumps be hermetically sealed to ensure operation with significantly reduced outlet pressure without any gas or oil leaks. It is particularly preferred that the outlet pressure of the backing pump during the pause and / or hold operation is in the range of 10 mbar to 500 mbar. In addition, it is particularly preferred to ensure operation at outlet pressures where the temperature characteristics of the pump are significantly reduced. This aspect is particularly relevant to clearance height, oil viscosity and bearing lubrication.

Furthermore, it is particularly preferred that the oil-lubricated space be sealed to the work space so that the oil does not diffuse violently even in very fast cycles. Further, the sealed portion of the shaft is preferably configured so that it is not prematurely damaged by wear caused by rapidly changing pressure differences. One possibility in this regard is the use of compensation lines between the oil-lubricated space and the work space with the oil separator.

Further favorable configurations and changes are shown in the drawings below. However, the features provided by each are not limited to individual drawings or configurations. More precisely, one or more of the features described above may be combined with the individual features or features of the drawing for further modification.

It is a figure which shows the embodiment which concerns on the example of the prior art. It is a figure which shows the embodiment which concerns on the example of the prior art. It is a figure which shows the embodiment which concerns on the example of the prior art. It is a figure which shows the exemplary embodiment which concerns on this invention. It is a figure which shows the exemplary embodiment which concerns on this invention. It is a figure which shows the exemplary embodiment which concerns on this invention.

1, the lock chamber 10, shows the vacuum pump system 1 that includes a pump P ₁ to P ₅ which are connected in parallel, the pump P ₁ to P ₅ are coupled with each lock chamber 10 and the inlet side There is. Further, the vacuum pumping system 1 includes a valve V ₁ ~V _5, the valve V ₁ ~V _5, coupling may be cut off from the pump inlet of pump P ₁ to P ₅ to the lock chamber 10. The illustrated vacuum pump system is known in the prior art. Valves V _{1 to} V ₅ are open during delivery time. Pumps P _{1 to} P ₅ consume a lot of power during the delivery time and operate at maximum speed. The pressure in the lock chamber is continuously reduced.

During the downtime, valves V _{1 to} V ₅ are closed, pumps P _{1 to} P ₅ operate at maximum speed, and power consumption is essentially equivalent to power consumption when operating at discharge pressure. It remains relatively high. The pressure in the lock chamber is equal to the transfer pressure.

During the holding time, valves V _{1 to} V ₅ are open and pumps P _{1 to} P ₅ operate at low working pressure.

The vacuum pump system 2 shown in FIG. 2 is known in the prior art. The vacuum pump system 2 is extended by a relatively large auxiliary pump P ₂₆ and check valves CV _{21 to} CV ₂₅ .

Pumps P _{21 to} P ₂₅ connected in parallel are connected to chamber 20. Both valves V _21- V ₂₅ and check valves CV _21- CV ₂₅ are open during delivery time. Inlet pressure of the additional auxiliary pump P ₂₆ is substantially equal to the outlet pressure of the auxiliary pump.

Valves V _21- V ₂₅ are closed during the downtime. After that, the check valves CV _{21 to} CV ₂₅ are also closed. During this operation, the inlet pressure of the auxiliary pump P ₂₆ is substantially less than the outlet pressure of the auxiliary pump P _26.

FIG. 3 shows the prior art configuration of the vacuum pump system 3 for the lock chamber 30 with the small auxiliary pumps P ₃₃ , P ₃₄ . For example, the ejector pump may be selected as the auxiliary pump.

Valves V ₃₁ , V ₃₂ and check valves C V ₃₁ , CV ₃₂ are open during delivery time. Inlet pressure of the auxiliary pump P _33, P ₃₄ is substantially equal to the outlet pressure of the auxiliary pump P _33, P _34.

Valves V ₃₁ and V ₃₂ are closed during the downtime of vacuum pump system 3.

Check valves CV ₃₁ and CV ₃₂ are also closed during the pause. Outlet pressure of the auxiliary pump P _33, P ₃₄ during downtime, substantially higher than the inlet pressure of the auxiliary pump P _33, P _34.

FIGS. 4 to 6 show the configuration of the vacuum pump system 4 according to the present invention.

The vacuum pump system shown in FIG. 4 comprises five vacuum pumps P ₄₁ , P ₄₂ , P ₄₃ , P ₄₄ , P ₄₅ connected in parallel. The inlets of the vacuum pumps P ₄₁ , P ₄₂ , P ₄₃ , P ₄₄ , P ₄₅ are connected to the vacuum chamber 40. Valves V ₄₁ , V ₄₂ , V ₄₃ , V ₄₄ , V ₄₅ are installed between the respective vacuum pumps P ₄₁ , P ₄₂ , P ₄₃ , P ₄₄ , P ₄₅ . The outlet side of the pumps P ₄₁ , P ₄₂ , P ₄₃ , P ₄₄ , P ₄₅ is connected to the common outlet 41 via check valves CV ₄₁ , CV ₄₂ , CV ₄₃ , CV ₄₄ , CV ₄₅ .

In an exemplary embodiment of the vacuum pump system of FIG. 4, pump P ₄₁ may be connected in series with pumps P ₄₂ , P ₄₃ , P ₄₄ , P ₄₅ at a connecting line 42 where valve V ₄₆ is located.

The vacuum pump P ₄₁ used as a backing pump or an auxiliary pump can generally be configured smaller than other vacuum pumps. Therefore, the power consumption during the hibernation operation and / or the holding operation is further reduced. FIG. 4 shows a vacuum pump system in which valves V _41- V ₄₅ are open and valves V ₄₆ are closed during delivery time. Furthermore, the check valves CV _{41 to} CV ₄₅ are open during the delivery time.

During the downtime, valves V _{41 through} V ₄₅ are closed and valve V ₄₆ is open. The check valve CV ₄₁ is also open during this operation as long as the contents in the pump system are ejected by pump P ₄₁ . After that, the check valve CV ₄₁ is closed. Check valves CV _{42 to} CV ₄₅ are closed during hibernation. The reduction in power consumption in hibernation can be up to 40% in some exemplary embodiments. In particular, the above-mentioned series connection of a vacuum pump as a backing pump can be further used to improve the supply of light gas. In addition, this pump connection can be further used to regulate chamber pressure or processing flow. The auxiliary pump ensures that the working pressure range is reached. Therefore, the backing pump can be reliably adjusted within a very large speed range.

FIG. 5 shows the minimal arrangement for the lock chamber. In the exemplary embodiment of FIG. 5, a vacuum pump system 5 having only two vacuum pumps P ₅₁ and P ₅₂ is selected as an example. These vacuum pumps have a common inlet line connected to the vacuum chamber 50 via valve V ₅₂ . Only the outlet of the vacuum pump P ₅₂ is connected to the common outlet 51 via a check valve CV ₅₁ . The outlet of the vacuum pump P ₅₁ is directly connected to the common outlet 51. Through an additional line 52 where valve V ₅₁ is located and extends from the outlet of pump P _{52 to} the inlet of pump P ₅₁ , pump P ₅₁ both sides the contents in the other pump P ₅₂ during pauses. Can be discharged from. However, in the example of FIG. 5, pump P ₅₁ and pump P ₅₂ cannot be connected in series.

Similar to FIG. 5, FIG. 6 shows the minimal configuration for the processing chamber. During the holding time, valve V ₆₁ is open so that the contents of pumps P ₆₂ , P ₆₁ are drained from both sides. Valve V ₆₁ is closed so that the contents in the processing chamber can be expelled in a short time during the delivery time. In both vacuum pump system 5 and vacuum pump system 6 configurations, additional pumps can be connected in parallel with pumps P ₅₂ , P ₆₂ and can be operated accordingly.

The solutions described herein can be implemented for combinations with two or more backing pumps. The number and size of each pump can be freely adapted to the application. Roots pumps connected in series with the backing pump generally do not affect the solution. Therefore, the roots pump is not shown in the example.

Claims (8)

A vacuum pump system,
Are connected in parallel, a plurality of vacuum pumps that are people connected Chang bar and husband on the inlet side,
An outlet line which is connected to the outlet side of the vacuum pump,
The inlet side of the at least one vacuum pump and an intermediate line which is connected to the outlet line,
The outlet side of the plurality of vacuum pumps is connected to the outlet line via a check valve, respectively.
During transmission time, all of the vacuum pump is connected in parallel, during downtime, at least one inlet side of the plurality of vacuum pumps is connected to the outlet side of the rest of the vacuum pump as a backing pump A vacuum pump system characterized by being. The vacuum pump system according to claim 1, wherein the vacuum pump whose inlet side is connected to the outlet side of the remaining vacuum pump during the downtime is connected in series with another vacuum pump. Each in a plurality of connecting lines that are a plurality of vacuum pumps and said chamber and each connected, valves for opening and closing the connection line is arranged, separate valves for opening and closing the intermediate line before serial are arranged in the intermediate line,
The vacuum pump system according to claim 1 or 2 , wherein the valve and the other valve are arranged to control the parallel or series interconnection of individual vacuum pumps. Claim 1 characterized in that at least one of the vacuum pumps in which the inlet side is connected to the outlet side of the remaining vacuum pumps in a dormant state and is particularly connected in series with the other vacuum pumps is smaller than the other vacuum pumps. The vacuum pump system according to any one of 3 to 3 . A way to evacuate the chamber
By connecting the inlet side of each of the plurality of vacuum pumps to the chamber and connecting the outlet side of each of the plurality of vacuum pumps to the outlet line via each check valve, the plurality of vacuum pumps can be connected. Connected in parallel with each other
At least one inlet side of the plurality of vacuum pumps is connected to the outlet line via an intermediate line.
During the delivery time, all vacuum pumps are connected in parallel,
A method characterized in that at least one inlet side of the plurality of vacuum pumps is connected to the outlet side of the remaining vacuum pumps as a backing pump during a pause time. The method of claim 5, wherein a vacuum pump whose inlet side is connected to the outlet side of the remaining vacuum pumps is connected in series with another vacuum pump during the downtime. A valve for opening and closing the connecting line is arranged in each of the plurality of connecting lines connecting the chamber and the plurality of vacuum pumps.
Another valve that opens and closes the intermediate line is placed in the intermediate line.
The method of claim 5 or 6, wherein the valve and the other valve are arranged to control the parallel or series interconnection of individual vacuum pumps. 5. A vacuum pump in which the inlet side is connected to the outlet side of the remaining vacuum pumps in a dormant state, and in particular at least one of the vacuum pumps connected in series with the other vacuum pumps is smaller than the other vacuum pumps. The method according to any one of 7 to 7.

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