KR102235562B1 - 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 is a gas inlet opening 2 connected to the vacuum chamber 1 and prior to opening of the pumping system SP, SPP to the gas outlet 8 A first lubrication vane screw vacuum pump (3) with a gas outlet opening (4) that opens to the conduit (5), a check valve located in the conduit (5) between the gas outlet opening (4) and the gas outlet (8) (6) And, it includes an ejector (7) connected in parallel with the check valve (6). According to the method, the first lubrication 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 ejector 7 is supplied with a working medium, the first lubrication screw vacuum pump 3 is pumping the gas contained in the vacuum chamber 1 throughout the time and/or the first lubrication screw vacuum pump 3 is The starting medium is continuously supplied to the ejector 7 throughout 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

Pumping method and vacuum pump system in a pumping system {Method of Pumping in a Pumping System And Vacuum Pump System}

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

The general trend of improving the performance of vacuum pumps in the industrial field, reducing installation costs and reducing energy consumption has resulted in remarkable developments in terms of performance, energy economy, and volume in driving parts.

Current technology indicates that improving the final vacuum and reducing the consumption of energy replenishment stages must be added to vacuum pumps of the multi-stage roots type or multi-stage claw type. For screw vacuum pumps, there must be an additional rotation of the screw and/or the rate of internal compression must be increased. For lubricated rotary vane vacuum pumps, one or more supplementary steps have to be added in series and the rate of internal compression has to be increased.

The current technology for pumping systems with the aim of improving the final vacuum and increasing the flow rate refers to booster pumps of the route type arranged upstream from the first lubricating rotary vane pumps. Systems of this type are bulky and operate as bypass valves that present a problem of reliability, or by employing means of measuring, controlling, regulating or servo control. However, this means of control, regulation or servo control must be controlled in an active manner, which inevitably leads to an increase in system components, complexity and cost.
On the other hand, international publication WO 2014/012896 discloses a "method and apparatus for pumping a process chamber", and French application FR 2 952 683 discloses a "pumping method and apparatus with low power consumption", and Japanese Laid-Open Patent Publication In Japanese Unexamined Patent Publication 2007-100562, "a vacuum device is disclosed.

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

It is also an object of the present invention to propose a pumping method of a pumping system capable of obtaining a flow rate higher than that obtained with the aid of a single lubricating rotary vane vacuum pump during pumping of a vacuum chamber at a low pressure.

Moreover, it is an object of the present invention to propose a pumping method of a pumping system that makes it possible to obtain a vacuum better than that obtained with the aid of a single lubricating rotary vane vacuum pump in a vacuum chamber.

The above objects of the present invention are achieved with the help of a pumping method made in the structure of the pumping system, wherein the configuration of the pumping system includes a gas inlet port connected to the vacuum chamber, and a check valve before exiting to the atmosphere or other devices. It consists of a first lubricating rotary vane vacuum pump installed with a gas outlet port leading to a conduit installed in the. The suction end of the ejector is connected in parallel to the check valve, and its outlet is bonded back to the conduit of the first pump after the check valve or goes to the atmosphere.

Such pumping methods are in particular the subject of independent claim 1. Different preferred embodiments of the invention are the subject of the dependent claims.

The method consists essentially of supplying a working fluid to the ejector and continuously operating it while the first lubricating rotary vane vacuum pump pumps the gas contained in the vacuum chamber through the gas inlet port, but also rises through the outlet. It consists in doing so throughout the first lubricating rotary vane vacuum pump maintaining a defined pressure (eg final vacuum) in the chamber by discharging the gas.

According to the first aspect, the present invention is a combination of a first lubrication rotary vane vacuum pump and an ejector measuring and specific devices (for example, sensors such as pressure, temperature, current), servo control, or data management and calculation. It is in that it does not need. Consequently, a pumping system suitable for implementing the pumping method according to the present invention contains a minimum of components, is very simple and is much cheaper than existing systems.

Due to its feature, the ejector integrated into the pumping system can be operated at all times without damage according to the current pumping method. Its dimensional setting is determined by the minimum consumption of working fluid for the 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, defined by a 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 greater or less than these values. The working fluid for the ejector may be compressed air, but may be other gases, for example nitrogen.

The non-return valve is disposed in the conduit at the outlet of the first lubricating 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 lubrication rotary vane vacuum pump. In particular, it is expected that the check valve closes when the pressure at the suction end of the first lubrication rotary vane vacuum pump is between 500 mbar absolute and the final pressure (eg 100 mbar).

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

According to another variant, the ejector may be made of a material having chemical resistance to gases and substances commonly used in the chemical industry and the semiconductor industry, even in a single stage ejector variant, such as in a multi-stage ejector.

The ejector is preferably compact.

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

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

According to another variant of the method of the present invention, the gas flow rate at the pressure required for operation of the ejector is controlled in an "all or nothing" way to meet certain requirements. In practice, control consists of measuring one or more parameters and activating or stopping the ejector according to certain predetermined rules. The parameters provided by suitable 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 a check valve, or these parameters. It is a combination of them.

Beginning with the cycle of emptying the chamber, the pressure in it rises, e.g. equal to atmospheric pressure. When compression is performed in the first lubrication rotary vane vacuum pump, the pressure of the gas discharged from its outlet is higher than the atmospheric pressure (if the gas from the outlet of the first pump is discharged directly to the atmosphere), or downstream Higher than the pressure at the inlet of other devices connected to the side. This causes the check valve to open.

When the check valve is open, the action of the ejector feels very weak as the pressure at its inlet is approximately equal to the pressure at its outlet. In contrast, when the check valve is closed at a certain pressure (because the pressure in the chamber drops in between), the action of the ejector will gradually reduce the pressure difference between the conduit and the chamber after the check valve. The pressure at the outlet of the first lubrication rotary vane vacuum pump becomes 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. The more the ejector is pumped, the greater the pressure drop at the outlet of the first lubricating rotary vane vacuum pump in the closed space (defined by the check valve), and eventually the pressure between the outlet and the chamber of the first lubricating rotary vane vacuum pump. The difference decreases. This slight difference reduces internal leakage in the first lubricating rotary vane vacuum pump and at the same time causes a pressure reduction in the chamber, which makes it possible to improve the final vacuum. Moreover, the first lubricating rotary vane vacuum pump consumes less energy for compression and generates less compression heat.

In the case of the control of the ejector, there is an initial position for starting the pumping system when the sensors are in a defined state or provide an initial value. As the first lubrication rotary vane vacuum pump pumps the gas from 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 detected by the sensors. Reach. This causes a switch action in the ejector. When these parameters return to their initial range (out of the set values) with a time lag, the ejector stops.

According to another variant of the invention, the gas flow at the pressure required for operation of the ejector is provided by the compressor. In a notable way, this compressor can be driven by a first lubricating rotary vane vacuum pump, or alternatively or additionally, in an autonomous manner independently of the first lubricating rotary vane vacuum pump. Such a compressor can draw atmospheric air or gas from the gas outlet conduit after the check valve. The presence of such a compressor makes the first lubricating rotary vane vacuum pump system independent of the compressed gas source, which can meet the needs of certain industrial environments. The compressor can provide a flow of gas at the pressure required for operation of a plurality of ejectors, which form part of a plurality of vacuum pump systems each having a first lubricating rotary vane vacuum pump. The compressor forms part of the system not only in the case of parameter dependent control, controlled by suitable sensors, but also in the case of continuous operation of the ejector.

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.

Features and advantages of the present invention will be presented as details in the detailed description, which are described with reference to the accompanying drawings, by way of example and not limitation, with the given embodiments.
1 schematically shows a pumping system suitable for implementing a pumping method according to first embodiments of the present invention.
2 schematically shows a pumping system suitable for implementing a pumping method according to a second embodiment of the present invention.
3 schematically shows a pumping system suitable for implementing a pumping method according to a third embodiment of the present invention.

1 shows a pump system SP suitable for implementing a pumping method according to a 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 lubricating rotary vane vacuum pump 3. The gas outlet port of the first lubrication rotary vane vacuum pump 3 is connected to the conduit 5. A non-return discharge valve 6 is arranged in the conduit 5 which continues after the check valve 6 to the gas outlet conduit 8. The non-return valve 6 allows the formation of a space 4 contained between itself and the gas outlet port of the first vacuum pump 3 when closed. The pump system SP also includes an ejector 7, which is connected in parallel with a 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 the working fluid for the ejector 7.

From the start of the first lubrication rotary vane vacuum pump 3, the working fluid for the ejector 7 is injected through the supply conduit 9. Next, the first lubrication rotary vane vacuum pump (3) sucks the gas in the chamber (1) through a port (2) connected to its inlet and compresses the gas, which is then checked at the outlet in the conduit (5) It is 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 gradually reduces the pressure in the space 4 to its limiting pressure value. In parallel, the power consumed by the first lubricating rotary vane vacuum pump 3 is gradually reduced. This occurs in a short period of time, for example during 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, the evacuation cycle is It is possible to reduce the time before closing of the check valve 6 in relation to the duration and thus reduce the loss of the working fluid during the operating time of the ejector 7 without affecting pumping. Moreover, these "losses" are small and are taken into account in the assessment of energy consumption. On the other hand, compared to similar pumps equipped with programmable automatic control and/or speed controllers, controlled valves, sensors, etc., the advantage of simplicity imparts excellent reliability as well as low cost to the system.

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

With respect to the system shown in FIG. 1, the system shown in FIG. 2 further comprises a compressor 10 that provides a flow of gas at the pressure required for operation of the ejector 7. In practice, such a compressor 10 can suck in gas or atmospheric air at the gas outlet 8 after the check valve 6. Its presence makes the pumping system independent of the compressed gas source, which can meet the requirements of certain industrial environments. The compressor 10 can be driven by the first lubricating rotary vane pump 3 or its own electric motor, and thus can be driven in a completely independent manner from the pump 3. In all cases, the energy consumption of the compressor 10 in providing the gas flow at the pressure required to operate the ejector 7 is substantially small compared to the advantages achieved in 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.

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

In particular, the present invention may have various modifications with respect to its implementation. Although various embodiments have been described, it will be understood that it cannot be construed to present all possible embodiments in an exhaustive manner. Of course, it is conceivable to replace the described means with equivalent means without departing from the scope of the invention. All of these variations form part of the common knowledge of those skilled in the vacuum arts.

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 having a gas inlet port 2 connected to the vacuum chamber 1 and a gas outlet port 4 leading to a conduit 5 before exiting the gas outlet 8 of the pumping system SP, SPP Vacuum pump (3),
A non-return valve (6) located in the conduit (5) between the gas outlet port (4) and the gas outlet (8),
An ejector (7) connected in parallel with the check valve (6) and,
As a pumping method of a pumping system (SP, SPP) including a compressor 10,
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 working fluid is supplied to the ejector 7 by the compressor 10 driven by the force driving the first lubrication rotary vane vacuum pump 3;
While the first lubricating rotary vane vacuum pump 3 pumps the gas contained in the vacuum chamber 1 or while the first lubricating rotary vane vacuum pump 3 maintains a predetermined pressure in the vacuum chamber 1 , The operating fluid is continuously supplied to the ejector 7,
Pumping method, characterized in that the working fluid of the ejector (7) is compressed air. The method of claim 1,
Pumping method, characterized in that the outlet of the ejector (7) is re-joined with the conduit (5) after the check valve (6). The method according to claim 1 or 2,
Pumping method, characterized in that the dimensions of the ejector (7) are determined to consume a minimum of working fluid. The method according to claim 1 or 2,
Pumping, characterized in that the nominal flow rate of the ejector 7 is selected in accordance with the volume of the outlet conduit 5 of the first lubricated rotary vane vacuum pump 3 limited by the check valve 6 Way. The method of claim 4,
Pumping method, characterized in that the nominal 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). The method according to claim 1 or 2,
Pumping method, characterized in that the ejector 7 is single-staged or multi-staged. The method according to claim 1 or 2,
Pumping method, characterized in that the check valve 6 is closed when the pressure at the suction end of the first lubrication rotary vane vacuum pump 3 is between 500 mbar as absolute pressure and the final vacuum. The method according to claim 1 or 2,
The ejector 7 is a pumping method, characterized in that it is made of a material having high chemical resistance to gases and substances commonly used in the chemical industry or the semiconductor industry. The method according to claim 1 or 2,
Pumping method, characterized in that the ejector (7) is integrated into a cartridge (cartridge) included in the check valve (6). The method of claim 9,
The pumping method, characterized in that the cartridge itself is accommodated in the oil separator of the first lubricating rotary vane vacuum pump. The method according to claim 1 or 2,
The pumping method, characterized in that the compressor (10) sucks atmospheric air or gas in the gas outlet conduit (8) after the check valve (6). A first lubricated rotary vane vacuum having a gas inlet port 2 connected to the vacuum chamber 1 and a gas outlet port 4 leading to a conduit 5 before exiting the gas outlet 8 of the system of the vacuum pump SP. Pump (3),
A non-return valve 6 located in the conduit 5 between the gas outlet port 4 and the gas outlet 8,
An ejector 7 connected in parallel to the check valve 6 and,
Including a compressor (10),
The compressor 10 is driven by a force driving the first lubrication rotary vane vacuum pump 3,
The first lubrication rotary vane vacuum pump 3 acts to pump the gas contained in the vacuum chamber 3 through the gas outlet port 4, and at the same time, the working fluid is supplied to the ejector 7 by the compressor. Become,
While the first lubricating rotary vane vacuum pump 3 pumps the gas contained in the vacuum chamber 1, or while the first lubricating rotary vane vacuum pump 3 maintains a predetermined pressure in the vacuum chamber 1 Throughout, it is configured to supply a working fluid to the ejector 7 by the compressor 10,
Pumping system (SP, SPP), characterized in that the working fluid of the ejector 7 is compressed air. The method of claim 12,
Pumping system, characterized in that the outlet of the ejector (7) is re-joined with the conduit (5) after the check valve (6). The method of claim 12 or 13,
Pumping system, characterized in that the dimensions of the ejector (7) are set so as to consume a minimum of working fluid. The method of claim 12 or 13,
Pumping system, characterized in that the nominal flow rate of the ejector (7) is selected in accordance with the volume of the outlet conduit (5) of the first lubricating rotary vane vacuum pump (3) limited by the check valve (6). The method of claim 15,
Pumping system, characterized in that the nominal 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). The method of claim 12 or 13,
Pumping system, characterized in that the ejector (7) is single-stage or multi-stage. The method of claim 12 or 13,
Pumping system, characterized in that the check valve (6) is closed when the pressure at the suction end of the first lubrication rotary vane vacuum pump (3) is between 500 mbar as absolute pressure and the final vacuum. The method of claim 12 or 13,
The ejector 7 is a pumping system, characterized in that it is made of a material having high chemical resistance to gases and substances commonly used in the chemical industry or the semiconductor industry. The method of claim 12 or 13,
Pumping system, characterized in that the ejector (7) is integrated into a cartridge comprising a check valve (6). The method of claim 20,
The pumping system, characterized in that the cartridge itself is housed in the oil separator of the first lubricating rotary vane vacuum pump. The method of claim 12 or 13,
A pumping system, characterized in that the compressor (10) sucks atmospheric air or gas in the gas outlet conduit (8) after the check valve (6).

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