KR20170005410A - Method of Pumping in a Pumping System And Vacuum Pump System - Google Patents

Abstract

The present invention relates to a pumping method in a pumping system (SP, SPP) which comprises a gas inlet opening (2) connected to a vacuum chamber (1) and a pre- A first lubricating vane screw vacuum pump 3 having a gas outlet opening 4 opening to the conduit 5 at the outlet 5 and a check valve 5 located at the conduit 5 between the gas outlet opening 4 and the gas outlet 8, (6), and an ejector (7) connected in parallel with the check valve (6). According to the above method, the first lubricating vane screw vacuum pump 3 is operated to pump the gas contained in the vacuum chamber 1 through the gas outlet opening 4; At the same time, the working medium is supplied to the ejector 7, and the first lubrication screw vacuum pump 3 and the first lubrication screw vacuum pump 3 are purged during the time that the gas contained in the vacuum chamber 1 is pumped and / The ejector 7 is continuously supplied with the starting medium over the period of maintaining the predetermined pressure in the vacuum chamber 1. [ The present invention relates to a pumping system (SP, SPP) suitable for use in implementing the method.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pumping method for a pumping system,

The present invention relates to a pumping method capable of reducing the consumption of electrical energy as well as improving performance associated with flow rate and final vacuum in a pumping system in which the main pump is a lubricating rotary vane vacuum pump. The present invention also relates to a pumping system which can be used to achieve the method according to the invention.

The general tendency to improve the performance of vacuum pumps, reduce installation costs and reduce energy consumption in the industrial sector has led to significant advances in terms of performance, energy economy, and volume at the drives.

The current technology indicates that to improve the final vacuum and to reduce the consumption of energy replenishment steps must be added to multi-stage Roots type or multi-stage claw type vacuum pumps. For screw vacuum pumps, there must be additional rotation of the screw and / or the rate of internal compression must be increased. One or more supplemental steps must be added in series for the lubrication rotary vane vacuum pumps and the rate of internal compression must be increased.

Current techniques for pumping systems with the goal of improving the final vacuum and increasing the flow rate are root type booster pumps located upstream from the first lubrication rotary vane pumps. These types of systems are operated by bypass valves that are bulky and exhibit reliability problems, or by employing measures, controls, adjustments or servo control means. However, the means of such control, regulation or servo control must be controlled in an active manner, which inevitably leads to an increase in system components, complexity and cost.

It is an object of the present invention to propose a pumping method of a pumping system which not only reduces the temperature of the outlet gas but also can reduce the electrical energy required to keep the chamber under vacuum and to maintain the vacuum in the chamber.

It is also an object of the present invention to propose a pumping system pumping method capable of achieving a higher flow rate at a lower pressure than can be obtained with the aid of a single lubrication rotary vane vacuum pump during pumping of the vacuum chamber.

It is a further object of the present invention to propose a pumping system pumping method which allows a vacuum to be obtained in a vacuum chamber that is superior to that obtainable with the aid of a single lubrication rotary vane vacuum pump.

The above objects of the present invention are achieved with the aid of a pumping method in the structure of a pumping system which comprises a gas inlet port connected to a vacuum chamber and a check valve, And a first lubrication rotary vane vacuum pump in which a gas outlet port leading to a conduit provided in the first lubrication rotary vane vacuum pump is installed. The suction end of the ejector is connected in parallel to the check valve and its outlet is connected again to the conduit of the first pump after the check valve or to the atmosphere.

Such a pumping method is in particular the subject of independent claim 1. The different preferred embodiments of the invention are subject of the dependent claims.

The method consists essentially of supplying a working fluid to the ejector and continuously operating it while the first lubrication rotary vane vacuum pump is pumping the gas contained in the vacuum chamber through the gas inlet port, Thereby allowing the first lubricating rotary vane vacuum pump to do so throughout the duration of maintaining the predetermined pressure (e.g., the final vacuum) in the chamber.

According to a first aspect, the present invention provides a method of controlling a vacuum pump comprising the steps of: coupling a first lubrication rotary vane vacuum pump and an ejector to a first lubrication apparatus, Is not required. As a result, a pumping system suitable for implementing the pumping method according to the present invention includes minimal components, is very simple, and is much cheaper than existing systems.

With that feature, the ejector incorporated in the pumping system can always be operated without damage due to the current pumping method. Its dimensioning is determined by the minimum consumption of working fluid for operation of the device. This is normally single staged. The nominal flow rate is selected according to the volume of the outlet conduit of the first lubricating rotary vane vacuum pump, which is defined by the check valve. This flow rate may be 1/500 to 1/20 of the nominal flow rate of the first lubricating rotary vane vacuum pump, but may be larger or smaller than these values. The working fluid for the ejector may be compressed air, but it may be other gas, for example nitrogen.

The check valve is disposed within the conduit at the outlet of the first lubrication rotary vane vacuum pump and may be a commercially available standard element. The dimension can be determined according to the nominal flow rate of the first lubricating rotary vane vacuum pump. In particular, it is expected that the check valve will close when the pressure at the suction end of the first lubricating rotary vane vacuum pump is between 500 mbar absolute and the final pressure (e.g., 100 mbar).

According to another variant, the ejector is multi-stage.

According to another variant, the ejector can be made of a material which is chemically resistant to gases and materials commonly used in the chemical and semiconductor industries, even in the single stage ejector variants, such as in multi-stage ejectors.

The ejector is preferably small.

According to another variant, the ejector is integrated into the cartridge including the check valve.

According to another variant, the ejector is integrated into the cartridge including the check valve, and the cartridge itself is housed in the oil separator of the first lubrication rotary vane vacuum pump.

According to another variant of the method of the invention, the gas flow rate at the pressure required for the operation of the ejector is controlled in an "all or nothing way" manner to meet certain requirements. In practice, control consists in measuring one or more parameters and activating or deactivating the ejector in accordance with certain predefined rules. The parameters provided by the appropriate sensors are, for example, the motor current of the lubricating rotary vane vacuum pump, the gas pressure or temperature in the space of the outlet conduit of the first lubricating rotary vane vacuum pump, defined by the check valve, Lt; / RTI >

Beginning with a cycle of emptying the chamber, the pressure therein rises and rises, for example, to atmospheric pressure. When compression is effected in the first lubricating rotary vane vacuum pump, the pressure of the gas exiting the outlet is higher than the atmospheric pressure (if the gas at the outlet of the first pump is discharged directly into the atmosphere) Is higher than the pressure at the inlet of the other device connected to the outlet. This causes the check valve to open.

When the check valve is opened, the action of the ejector feels very weak because the pressure at its inlet is almost the same as the pressure at its outlet. In contrast, the action of the ejector progressively reduces the pressure difference between the conduit and the chamber after the check valve when the check valve is closed at a certain pressure (because the pressure in the chamber falls between them). The pressure at the outlet of the first lubricating rotary vane vacuum pump is the pressure at the inlet of the ejector and the pressure at its outlet is always the pressure in the conduit after the check valve. As the ejector is further pumped, the pressure drop at the outlet of the first lubrication rotary vane vacuum pump (defined by the check valve) in the closed space is increased and eventually the pressure between the outlet of the first lubrication rotary vane vacuum pump and the chamber The difference decreases. This slight difference reduces the internal leakage in the first lubrication rotary vane vacuum pump and at the same time causes a reduction in pressure in the chamber, which makes it possible to improve the final vacuum. Moreover, the first lubrication rotary vane vacuum pump consumes less energy for compression and less heat of compression.

In the case of control of the ejector, there is an initial position for starting the pumping system when the sensors are in a predetermined state or provide an initial value. As the first lubrication rotary vane vacuum pump pumps the gas of the vacuum pump, parameters such as the current of its motor, the pressure and temperature of the gas in the space of the outlet conduit begin to change and the threshold value Lt; / RTI > This causes a switch action in the ejector. When these parameters return to the initial range with time lag (out of set values), the ejector is stopped.

According to another variant of the invention, the gas flow at the pressure required for the operation of the ejector is provided by the compressor. In a noteworthy manner, such a compressor can be driven by a first lubrication rotary vane vacuum pump, or alternatively or additionally, in an autonomous manner independent of the first lubrication rotary vane vacuum pump. Such a compressor is capable of sucking air or gas in the atmosphere from the gas outlet conduit after the check valve. The presence of such a compressor makes the first lubrication rotary vane vacuum pump system independent of the compressed gas source, which can meet the needs of specific industrial environments. The compressor can provide a flow of gas at the pressure required to operate the plurality of ejectors, each of which forms part of a plurality of vacuum pump systems having a first lubricating rotary vane vacuum pump. The compressor forms part of the system in the case of continuous operation of the ejector, as well as in the case of control according to parameters, which are controlled by appropriate sensors.

On the other hand, it is clear that the study of the mechanical concept seeks to reduce the space with the aim of lowering the pressure more quickly in the space between the gas outlet port of the first lubricating rotary vane vacuum pump and the check valve.

BRIEF DESCRIPTION OF THE DRAWINGS The features and advantages of the present invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, which illustrate, by way of example and not limitation,
1 schematically illustrates a pumping system suitable for implementation of the pumping method according to the first embodiment of the present invention.
Figure 2 schematically illustrates a pumping system suitable for implementation of the pumping method according to the second embodiment of the present invention.
Figure 3 schematically illustrates a pumping system suitable for implementation of the pumping method according to the third embodiment of the present invention.

1 shows a pump system SP suitable for implementing the pumping method according to the first embodiment of the present invention.

The pump system SP comprises a chamber 1, which is connected to the suction port 2 of the first lubrication rotary vane vacuum pump 3. The gas outlet port of the first lubricating rotary vane vacuum pump (3) is connected to the conduit (5). A non-return discharge valve 6 is disposed in the conduit 5, which continues to the gas outlet conduit 8 after the check valve 6. The check valve (6) allows the formation of a space (4) contained between the gas outlet port of the first vacuum pump (3) and itself when closed. The pump system SP also includes an ejector 7, which is connected in parallel with the check valve 6. The suction port of the ejector is connected to the space (4) of the conduit (5) and the discharge port is connected to the conduit (8). The supply conduit 9 provides a working fluid for the ejector 7.

From the start of the first lubricating rotary vane vacuum pump 3, the working fluid for the ejector 7 is injected through the supply conduit 9. The first lubrication rotary vane vacuum pump 3 then sucks the gas in the chamber 1 through the port 2 connected to its inlet and compresses the gas so that it is then discharged from the outlet in the conduit 5, And discharged through the valve 6. When the closing pressure of the check valve 6 is reached, the check valve is closed. Starting from this moment, the pumping of the ejector 7 progressively reduces the pressure in the space 4 to its limiting pressure value. In parallel, the power consumed by the first lubrication rotary vane vacuum pump 3 is gradually reduced. This occurs in a short period of time, for example, for a specific cycle of 5 to 10 seconds.

By wisely adjusting the closing pressure of the check valve 6 and the flow rate of the ejector 7 as a function of the space of the chamber 1 and the flow rate of the first lubricating rotary vane vacuum pump 3, It is possible to reduce the time before the check valve 6 is closed in relation to the duration and thus to reduce the loss of the working fluid during the operation time of the ejector 7 without affecting the pumping. Moreover, this "loss" is small and is taken into account in the assessment of energy consumption. On the other hand, the advantages of simplicity, as compared to similar pumps with programmable automatic control and / or speed controllers, controlled valves, sensors, etc., give the system excellent reliability as well as low cost.

Fig. 2 shows a pumping system SP suitable for implementing the pumping method according to the second embodiment of the present invention.

With regard to the system shown in Figure 1, the system shown in Figure 2 further includes a compressor 10 that provides a flow of gas at the pressure required for operation of the ejector 7. In practice, this compressor 10 is capable of sucking the air of the gas or atmosphere in the gas outlet 8 after the check valve 6. Its presence ensures that the pumping system is independent of the compressed gas source, which can meet the requirements of a particular industrial environment. The compressor 10 can be driven by the first lubrication rotary vane pump 3 or by its own electric motor and thus can be driven from the pump 3 in a completely independent manner. In all cases, the energy consumption of the compressor 10 when providing the gas flow at the pressure necessary to operate the ejector 7 is substantially small compared to the advantages achieved with the energy consumption of the main pump 3.

3 shows a system of a vacuum pump (SPP) suitable for carrying out the pumping method according to the third embodiment of the present invention.

In the context of the system shown in Figures 1 and 2, the system shown in Figure 3 corresponds to a controlled pumping system, which further comprises sensors 11, 12, 13, which, for example, (Sensor 13) of the gas in the space of the outlet conduit of the first lubricating rotary vane vacuum pump (limited by the check valve 6), the motor current (sensor 11) of the vane vacuum pump 3, (Sensor 12) or a combination of these parameters in the space of the outlet conduit of the first lubricating rotary vane vacuum pump. Indeed, when the first lubrication rotary vane vacuum pump 3 begins to pump the gas in the vacuum chamber 1, the parameters (in particular, the current of the motor, the pressure of the gas in the space at the outlet of the conduit 4, Temperature) begins to vary and reaches the threshold values detected by the corresponding sensor 11, 12, 13. This causes the ejector 7 to start (after a certain time lag). When the parameters return to the initial range (outside the set point), the ejector stops (again after a certain time delay). Of course, the controlled pumping system (SSP) may have the compressor 10 or the supply network as a compressed gas source under the conditions shown in FIG.

In particular, the present invention may have various modifications as regards its implementation. Although various embodiments have been described, it will be appreciated that not all possible embodiments may be conceived to be described in a manner that fully explains them. It is, of course, contemplated to replace the described means with equivalent means without departing from the scope of the present invention. All these variations form part of the common knowledge of those skilled in the art of vacuum technology.

1. Vacuum pump 3. First lubrication rotary vane vacuum pump
4. Gas outlet port 5. Conduit
6. Check valve 7. Ejector

Claims (34)

A first lubrication rotary vane 2 having a gas inlet port 2 connected to the vacuum chamber 1 and a gas outlet port 4 leading to the conduit 5 before exiting the gas outlet 8 of the pumping system SP, SPP, The vacuum pump 3,
A check valve (6) located in the conduit (5) between the gas outlet port (4) and the gas outlet (8)
A pumping system (SP, SPP) comprising an ejector (7) connected in parallel with a check valve (6)
The first lubrication rotary vane vacuum pump 3 is operated to pump the gas contained in the vacuum chamber 1 through the gas outlet port 4;
At the same time, the ejector 7 is supplied with working fluid;
The first lubrication rotary vane vacuum pump 3 maintains a predetermined pressure in the vacuum chamber 1 during the pumping of the gas contained in the vacuum chamber 1 and / or while the first lubrication rotary vane vacuum pump 3 maintains the predetermined pressure in the vacuum chamber 1 , The working fluid is continuously supplied to the ejector (7). The method according to claim 1,
And the outlet of the ejector (7) is again joined to the conduit (5) after the check valve (6). 3. The method according to claim 1 or 2,
Characterized in that the dimensions of the ejector (7) are set so as to consume minimal working fluid. 4. The method according to any one of claims 1 to 3,
Characterized in that the nominal flow rate of the ejector (7) is selected according to the volume of the outlet conduit (5) of the first lubricating rotary vane vacuum pump (3) limited by the check valve (6) Way. 5. The method of claim 4,
Characterized in that the flow rate of the ejector is 1/500 to 1/20 of the nominal flow rate of the first lubricating rotary vane vacuum pump (3). 6. The method according to any one of claims 1 to 5,
Characterized in that the working fluid of the ejector (7) is compressed air and / or nitrogen. 7. The method according to any one of claims 1 to 6,
Characterized in that the ejector (7) is single-stage or multi-stage. 8. The method according to any one of claims 1 to 7,
Characterized in that the check valve (6) is closed when the pressure at the suction end of the first lubricating rotary vane vacuum pump (3) is between 500 mbar absolute and the final vacuum. 9. The method according to any one of claims 1 to 8,
Characterized in that the ejector (7) is made of a material which is chemically and / or highly resistant to gases and materials commonly used in the chemical and / or semiconductor industries. 10. The method according to any one of claims 1 to 9,
Characterized in that the ejector (7) is incorporated into a cartridge contained in the check valve (6). 11. The method of claim 10,
Characterized in that the cartridge itself is received in an oil separator of a first lubricating rotary vane vacuum pump. 12. The method according to any one of claims 1 to 11,
Characterized in that the gas flow at the pressure required for the operation of the ejector (7) is provided by the compressor (10). 13. The method of claim 12,
Characterized in that the compressor (10) is driven by a first lubricating rotary vane vacuum pump (3). 13. The method of claim 12,
Characterized in that the compressor (10) is autonomously driven independently of the first lubrication rotary vane vacuum pump (3). 15. The method according to any one of claims 12 to 14,
Characterized in that the compressor (10) sucks atmospheric air or gas in the gas outlet conduit (8) after the check valve (6). 16. The method according to any one of claims 1 to 15,
Characterized in that at least one operating parameter is measured and used to start or stop the ejector (7). 17. The method of claim 16,
At least one operating parameter is determined by the motor current of the first lubricating rotary vane vacuum pump 3, the gas pressure in the space of the outlet conduit of the first lubricating rotary vane vacuum pump limited by the check valve 6, Is the temperature of the gas in the space of the outlet conduit of the first lubricating rotary vane vacuum pump limited by the temperature of the gas, or is a combination of the above parameters. A first lubrication rotary vane vacuum having a gas inlet port 2 connected to the vacuum chamber 1 and a gas outlet port 4 leading to the conduit 5 before exiting the gas outlet 8 of the system of the vacuum pump SP The pump 3,
A non-return valve 6 located in the conduit 5 between the gas outlet port 4 and the gas outlet 8,
And an ejector (7) connected in parallel to the check valve (6)
The first lubrication rotary vane vacuum pump 3 maintains the predetermined pressure in the vacuum chamber 1 while the first lubrication rotary vane vacuum pump 3 pumps the gas contained in the vacuum chamber 1 and / (SP, SPP), characterized in that the working fluid is supplied to the ejector during operation of the pump (SP, SPP). 19. The method of claim 18,
Characterized in that the outlet of the ejector (17) is reattached to the conduit (5) after the check valve (6). 20. The method according to claim 18 or 19,
Characterized in that the dimensions of the ejector (7) are set so as to consume minimal working fluid. 21. The method according to any one of claims 18 to 20,
Characterized in that the nominal flow rate of the ejector (7) is selected according to the volume of the outlet conduit (5) of the first lubricating rotary vane vacuum pump (3) limited by the check valve (6). 22. The method of claim 21,
Characterized in that the flow rate of the ejector is 1/500 to 1/20 of the nominal flow rate of the first lubricating rotary vane vacuum pump (3). 23. The method according to any one of claims 18 to 22,
Characterized in that the working fluid of the ejector (7) is compressed air and / or nitrogen. 24. The method according to any one of claims 18 to 23,
Characterized in that the ejector (7) is a single stage or multiple stages. 25. The method according to any one of claims 18 to 24,
Characterized in that the check valve (6) is closed when the pressure at the suction end of the first lubricating rotary vane vacuum pump (3) is between 500 mbar absolute and the final vacuum. 26. The method according to any one of claims 18 to 25,
Characterized in that the ejector (7) is made of a material with high chemical resistance to gases and materials commonly used in the chemical and / or semiconductor industries. 27. The method according to any one of claims 18 to 26,
Characterized in that the ejector (7) is incorporated in a cartridge comprising a check valve (6). 28. The method of claim 27,
Characterized in that the cartridge itself is received in an oil separator of a first lubricating rotary vane vacuum pump. 29. The method according to any one of claims 18 to 28,
Characterized in that the pumping system comprises a compressor (10) which provides a gas flow at a pressure necessary for the operation of the ejector (7). 30. The method of claim 29,
Characterized in that the compressor (10) is driven by a first lubricating rotary vane vacuum pump (3). 30. The method of claim 29,
Characterized in that the compressor (10) is autonomously driven independently of the first lubrication rotary vane vacuum pump (3). 32. The method according to any one of claims 29 to 31,
Characterized in that the compressor (10) sucks atmospheric air or gas in the gas outlet conduit (8) after the check valve (6). 32. The method according to any one of claims 18 to 32,
Characterized in that it comprises at least one sensor (11, 12, 13) which measures at least one operating parameter and which uses operating parameters to start or stop the ejector (7). 35. The method of claim 34,
At least one operating parameter is determined by the motor current of the first lubricating rotary vane vacuum pump 3, the gas pressure in the space of the outlet conduit of the first lubricating rotary vane vacuum pump limited by the check valve 6, Is the temperature of the gas in the space of the outlet conduit of the first lubricating rotary vane vacuum pump (3) limited by the temperature of the first lubricating rotary vane vacuum pump (3), or a combination of the above parameters.

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