JP6410836B2 - Pressure feeding method and vacuum pump system in a system for pressure feeding - Google Patents

Description

  The present invention relates to a pumping method that makes it possible to reduce the consumption of electrical energy and improve the performance with respect to flow rate and final vacuum in a pumping system in which the main pump is a lubricated rotary vane vacuum pump. Similarly, the present invention relates to a pumping system that can be used to accomplish the method of the present invention.

  The general trend in the industry to increase the performance of vacuum pumps and reduce equipment costs and energy consumption has led to significant developments in drive systems in terms of performance, energy economy, bulkiness, and the like.

  The state of the art has proven that an auxiliary stage must be added to a multistage root or multistage claw vacuum pump in order to improve the final vacuum and reduce energy consumption. In a screw vacuum pump, there must be an additional turn of the screw and / or the internal compressibility must be increased. In a lubricated rotary vane vacuum pump, one or more auxiliary stages must be added in series to increase the internal compressibility.

  The state of the art for a pumping system that attempts to improve the final vacuum and increase the flow rate is a root-type booster pump located upstream of the main lubricated rotary vane pump. This type of system works with bypass valves that cause bulk and reliability problems, or works with means of measurement, control, regulation or servo control. However, these control, adjustment or servo control means must be actively controlled, which inevitably results in an increase in the number of components of the system, its complexity and cost.

The present invention has the object of proposing a pumping method in a pumping system that makes it possible to reduce the electrical energy required to evacuate the chamber and maintain the vacuum in the chamber and to reduce the temperature of the outlet gas.
The invention also has the object of proposing a pumping method in a pumping system that makes it possible to obtain a flow rate that is greater than that obtainable with the aid of a single lubricated rotary vane vacuum pump at low pressure during pumping of the vacuum chamber. .
The invention also has the object of proposing a pumping method in a pumping system that makes it possible to obtain a better vacuum than can be obtained in the vacuum chamber with the aid of a single lubricated rotary vane vacuum pump.

  These objects of the present invention are achieved with the aid of the pumping method achieved in the framework of a pumping system, which essentially consists of a gas inlet port connected to a vacuum chamber, and in the atmosphere or other device. Consisting of a main lubricated rotary vane vacuum pump with a gas outlet port leading to a conduit with a check valve before exiting. The suction end of the ejector is connected in parallel to this check valve and its outlet reaches the atmosphere or, after the check valve, reconnects to the main pump conduit.

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

  Such a method essentially consists in discharging the rising gas through its outlet while the main lubricating rotor blade pump pumps the gas contained in the vacuum chamber through the gas inlet port. While the vacuum pump maintains a predetermined pressure (eg, final vacuum) in the chamber, it consists of supplying working fluid to the ejector and continuously operating the ejector.

  In accordance with the first aspect, the present invention does not require measurement and specific equipment (eg, pressure, temperature, current, etc.), servo control or data management and calculation to connect the main lubricated rotary vane vacuum pump and ejector. There is. Accordingly, a pumping system suitable for implementing the pumping method of the present invention has a minimal number of components, has excellent simplicity, and is much cheaper than existing systems.

  Due to its nature, the ejector integrated into the pumping system can always operate without damage according to such pumping method. Its sizing is determined by the minimum consumption of working fluid during operation of the device. The ejector is usually a single stage. Its nominal flow rate is selected depending on the volume of the outlet conduit of the main lubricated rotary vane vacuum pump which is limited by the check valve. This flow rate can be 1/500 to 1/20 of the nominal flow rate of the main lubricated rotary vane vacuum pump, but can be less than or greater than these values. The working fluid for the ejector can be compressed air, but can also be other gases, such as nitrogen.

  A check valve placed in the conduit at the outlet of the main lubrication rotary vane vacuum pump can be a standard component on the market. The check valve is dimensioned according to the nominal flow rate of the main lubricated rotary vane vacuum pump. In particular, it is foreseen that the check valve will close when the pressure at the suction end of the main lubricated rotary vane vacuum pump is between 500 millibar absolute pressure and the final vacuum (eg, 100 millibar).

In other variations, the ejector is multi-stage.
In yet another variation, in a single stage ejector variation, just like that of a multi-stage ejector, the ejector may be made from a material that has chemical resistance to materials and gases commonly used in the chemical and semiconductor industries. it can.
The ejector is preferably small.

In another variation, the ejector is integrated into a cartridge that incorporates a check valve.
In another variant, the ejector is integrated into a cartridge incorporating a check valve, which is itself housed in the oil separator of the main lubricating rotary vane vacuum pump.
In yet another variation 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” manner to meet specific requirements. In practice, control consists in measuring one or more parameters and activating or deactivating the ejector according to certain predetermined rules. Parameters supplied by suitable sensors are, for example, the motor current of the lubricated rotary vane vacuum pump, the temperature or pressure of the gas in the space of the outlet conduit of the main lubricated rotary vane vacuum pump, which is limited by a check valve, or these It is a combination of parameters.

  A vacuum evacuation cycle of the chamber is initiated and the pressure therein is increased, for example, equal to atmospheric pressure. When compression is applied in the main lubrication rotary vane vacuum pump, the pressure of the gas discharged from its outlet is higher than atmospheric pressure (if the gas at the outlet of the main pump is discharged directly into the atmosphere), Or it is higher than the pressure in the inlet_port | entrance of the other apparatus connected downstream. This causes the check valve to open.

  When the check valve is open, the operation of the ejector is felt very lightly because the pressure at its inlet is close to the pressure at its outlet. In contrast, when the check valve closes at a constant pressure (because the pressure in the chamber has dropped in the meantime), the operation of the ejector will cause a pressure differential between the chamber and the conduit after the check valve. Causes a gradual decrease. The pressure at the outlet of the main lubricating rotary vane vacuum pump becomes the pressure at the inlet of the ejector, and the pressure at the outlet is always the pressure in the conduit after the check valve. The more the ejector pumps, the lower the pressure at the outlet of the main lubrication rotor vacuum pump in a closed space (limited by the check valve), resulting in the chamber and the main lubrication rotor vacuum pump. The pressure difference between the outlet and the outlet becomes smaller. This slight difference reduces internal leakage in the main lubricated rotary vane vacuum pump and at the same time causes a drop in pressure in the chamber, which makes it possible to improve the final vacuum. Furthermore, the main lubricated rotary vane vacuum pump consumes a smaller amount of energy for compression and produces a smaller amount of compression heat.

  In the case of controlling the ejector, there is an initial position for starting the pumping system when the sensor is in a predetermined state or gives an initial value. When the main lubricated rotary vane vacuum pump pumps the gas in the vacuum chamber, parameters such as the motor current, the temperature and pressure of the gas in the outlet conduit space begin to change and reach the threshold detected by the sensor. This causes the ejector to switch on. When these parameters return to the initial range (outside the set value) with a time lag, the ejector is stopped.

  In yet another variation 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, the compressor can be driven independently of the main lubricated rotary vane pump by the main lubricated rotary vane pump, or alternatively or in addition. This compressor can suck in the gas in the gas outlet conduit after the atmosphere or check valve. The presence of such a compressor makes the lubricated rotary vane vacuum pump system independent of the compressed gas source, thereby meeting certain industrial environment requirements. The compressor can supply a flow of gas at a pressure required for operation of a plurality of ejectors, each forming part of a plurality of vacuum pump systems having a lubricated rotary vane vacuum pump as the main pump. The compressor forms part of the system both when the ejector is operating continuously and also when it is controlled according to parameters controlled by appropriate sensors.

  On the other hand, it is also clear that research on the mechanical concept is trying to reduce the space between the gas outlet port of the main lubricated rotary vane vacuum pump and the check valve in order to reduce the pressure there more quickly. It is.

  The features and advantages of the invention will become more apparent in the context of the following description. By way of example, and not limitation, examples are given in conjunction with the accompanying drawings.

1 schematically shows a pumping system suitable for carrying out a pumping method according to a first embodiment of the invention. 2 schematically shows a pumping system suitable for carrying out a pumping method according to a second embodiment of the invention. 3 schematically shows a pumping system suitable for carrying out a pumping method according to a third embodiment of the invention.

FIG. 1 shows a pumping system (SP) suitable for implementing the pumping method according to the first embodiment of the present invention.
The pumping system (SP) includes a chamber 1 connected to an intake port 2 of a main lubricating rotary vane vacuum pump 3. The gas outlet port of the main lubricating rotary vane vacuum pump 3 is connected to the conduit 5. A check valve 6 is placed in the conduit 5 and, after this check valve 6, continues into the gas outlet conduit 8. When closed, the check valve 6 enables the formation of a space 4 contained between the gas outlet port of the main lubricated rotary vane vacuum pump 3 and itself. The pressure feeding system (SP) also includes an ejector 7 connected in parallel to the check valve 6. The intake 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 supplies working fluid for the ejector 7.

  From the start of the main lubricating rotary vane vacuum pump 3, the working fluid of the ejector 7 is injected through the supply conduit 9. Thereafter, the main lubricated rotary vane vacuum pump 3 sucks the gas in the chamber 1 through the port 2 connected to its inlet, compresses it, and then exhausts it through the check valve 6 from the outlet of the pump in the conduit 5. . When the closing pressure of the check valve 6 is reached, the check valve 6 is closed. From this moment, the pressure in the space 4 gradually decreases to the limit pressure value by the pumping of the ejector 7. In parallel, the power consumed by the main lubricating rotary vane vacuum pump 3 gradually decreases. This occurs within a short period of time (e.g., in 5-10 seconds in some cycles).

  If the flow rate of the ejector 7 and the closing pressure of the check valve 6 are intelligently adjusted as a function of the flow rate of the main lubricated rotary vane vacuum pump 3 and the space of the chamber 1, before the check valve 6 is closed with respect to the duration of the vacuum exhaust cycle. It is further possible to reduce the working fluid loss during this operating time of the ejector 7 without affecting the pumping. In addition, this “loss” is small but considered in assessing energy consumption. On the other hand, the advantage of simplicity provides superior reliability and low cost of the system compared to similar pumps with programmable automatic control and / or speed controllers, controlled valves, sensors and the like.

FIG. 2 shows a pumping system (SP) suitable for carrying out the pumping method according to the second embodiment of the present invention.
In contrast to the system shown in FIG. 1, the system shown in FIG. 2 further comprises a compressor 10 that supplies a gas flow at a pressure required for the operation of the ejector 7. In practice, the compressor 10 can suck the atmosphere or the gas in the gas outlet 8 after the check valve 6. Due to its presence, the pumping system is independent of the compressed gas source, which can meet the requirements of certain industrial environments. The compressor 10 can be driven by the main lubricating rotary vane vacuum pump 3 or by its own electric motor and thus completely independent of the main lubricating rotary vane vacuum pump 3. In all cases, the energy consumption of the compressor 10 when supplying the gas flow at the pressure required to operate the ejector 7 is compared to the benefits achieved by the energy consumption of the main lubricated rotary vane vacuum pump 3. Significantly smaller.

FIG. 3 shows a vacuum pump system (SPP) suitable for carrying out the pumping method according to the third embodiment of the present invention.
3 corresponds to a controlled pumping system, for example, the motor current (sensor 11) of the main lubricated rotary vane vacuum pump 3, the main system shown in FIG. The pressure of the gas in the space of the outlet conduit (limited by the check valve 6) of the lubricated rotary vane vacuum pump 3 (sensor 13), the outlet of the main lubricated rotary vane vacuum pump 3 (limited by the check valve 6) Further provided are sensors 11, 12, 13 for controlling the temperature of the gas in the space of the conduit (sensor 12), or a combination of these parameters. In practice, when the main lubricated rotary vane vacuum pump 3 begins to pump the gas in the vacuum chamber 1, these mentioned parameters (especially the current of the motor, the temperature and pressure of the gas in the outlet conduit space 4) are: It begins to change and reaches the threshold detected by the corresponding sensor 11, 12, 13. This causes the start of the ejector 7 (after a certain time lag). When these parameters return to the initial range (outside the setpoint), the ejector is stopped (again after a certain time lag). Of course, the controlled pumping system (SSP) can have a supply network or the compressor 10 at the conditions shown in FIG. 2 as a source of compressed gas.

  Indeed, the present invention is subject to numerous variations with respect to its implementation. Although various embodiments have been described, it is well understood that it is not possible to exhaustively identify all possible embodiments. Of course, it is contemplated that equivalent means may be used in place of the means described without departing from the scope of the present invention. All of these modifications form part of the common knowledge of those skilled in the art of vacuum technology.

Claims (26)

A gas inlet port (4) connected to a gas inlet port (2) connected to the vacuum chamber (1) and a conduit (5) before coming into the gas outlet (8) of the pumping system (SP, SPP) A main lubricating rotary vane vacuum pump (3) having
A check valve (6) positioned in the conduit (5) between the gas outlet port (4) and the gas outlet (8);
A pumping method in a pumping system (SP, SPP) comprising an ejector (7) connected in parallel to the check valve (6),
The main lubricated rotary vane vacuum pump (3) is in operation to pump the gas contained in the vacuum chamber (1) through the gas outlet port (4);
At the same time, working fluid is supplied to the ejector (7),
While the main lubrication rotary vane vacuum pump (3) is pumping the gas contained in the vacuum chamber (1) and / or the main lubrication rotary vane vacuum pump (3) is in the vacuum chamber (1). during the) inside maintains a predetermined pressure, the connection working fluid is supplied to said ejector (7),
The ejector (7) is integrated with a cartridge incorporating the check valve (6), and the cartridge itself is housed in an oil separator of the main lubricating rotary vane vacuum pump (3). Pumping method. In the pumping method of Claim 1,
The pumping method according to claim 1, wherein the outlet of the ejector (7) is reconnected to the conduit (5) after the check valve (6). In the pumping method according to claim 1 or 2,
The pumping method according to claim 1, characterized in that the ejector (7) is dimensioned to have a minimum consumption of working fluid. In the pumping method in any one of Claims 1-3 ,
The pumping method according to claim 1, wherein the working fluid of the ejector (7) is compressed air and / or nitrogen. In the pumping method in any one of Claims 1-4 ,
The pumping method according to claim 1, wherein the ejector (7) is single-stage or multi-stage. In the pumping method in any one of Claims 1-5 ,
The pumping method according to claim 1, wherein the check valve (6) is closed when the pressure at the suction end of the main lubricating rotary vane vacuum pump (3) is between 500 millibar absolute pressure and the final vacuum. In the pumping method in any one of Claims 1-6 ,
The pumping method, characterized in that the ejector (7) is made of a material having a high chemical resistance to substances and gases commonly used in the chemical and / or semiconductor industries. In the pumping method in any one of Claims 1-7 ,
A pressure feeding method, wherein a gas flow having a pressure required for the operation of the ejector (7) is supplied by a compressor (10). The pumping method according to claim 8 , wherein
The compressor (10) is driven by a motor of the main lubricating rotary vane vacuum pump (3). The pumping method according to claim 8 , wherein
The compressor (10) is driven by an autonomous method and independently driven from the main lubricating rotary vane vacuum pump (3). In the pumping method in any one of Claims 8-10 ,
The compressor (10) sucks gas in the gas outlet (8) after the air or after the check valve (6). In the pumping method in any one of Claims 1-11 ,
Pumping method, characterized in that at least one operating parameter is measured and used to start or stop the ejector (7). The pumping method according to claim 12 ,
The at least one operating parameter is the motor current of the main lubrication rotary vane vacuum pump (3), the space of the conduit (5) of the main lubrication rotary vane vacuum pump (3) limited by the check valve (6). The pressure of the gas in the interior, the temperature of the gas in the space of the conduit (5) of the main lubricating rotary vane vacuum pump (3) limited by the check valve (6), or a combination of these parameters Pressure feeding method. A gas inlet port (4) connected to a gas inlet port (2) connected to the vacuum chamber (1) and a conduit (5) before coming into the gas outlet (8) of the pumping system (SP, SPP) A main lubricating rotary vane vacuum pump (3) having
A check valve (6) positioned 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 a pressure feeding system (SP, SPP),
While the main lubrication rotary vane vacuum pump (3) is pumping the gas contained in the vacuum chamber (1) and / or the main lubrication rotary vane vacuum pump (3) is in the vacuum chamber (1). The ejector (7) is configured so that working fluid can continue to be supplied to the ejector (7) while maintaining a predetermined pressure in
The ejector (7) is integrated with a cartridge incorporating the check valve (6),
The pressure feeding system , wherein the cartridge itself is accommodated in an oil separator of the main lubricating rotary vane vacuum pump (3) . The pumping system according to claim 14 ,
Pumping system, characterized in that the outlet of the ejector (7) reconnects to the conduit (5) after the check valve (6). The pumping system according to claim 14 or 15 ,
The pumping system, characterized in that the ejector (7) is dimensioned to have a minimum consumption of working fluid. In the pumping system in any one of Claims 14-16 ,
The pumping system according to claim 1, wherein the working fluid of the ejector (7) is compressed air and / or nitrogen. In the pumping system in any one of Claims 14-17 ,
The ejector (7) is a single-stage or multi-stage pumping system. In the pumping system in any one of Claims 14-18 ,
The non-return valve (6) closes when the pressure at the suction end of the main lubricating rotary vane vacuum pump (3) is between 500 millibar absolute pressure and the final vacuum. In the pumping system in any one of Claims 14-19 ,
The pumping system, characterized in that the ejector (7) is made from a material having a high chemical resistance to substances and gases commonly used in the chemical and / or semiconductor industries. In the pumping system according to any one of claims 14 to 20 ,
The pumping system, further comprising a compressor (10) for supplying a gas flow having a pressure required for the operation of the ejector (7). The pumping system according to claim 21 , wherein
The compressor (10) is driven by a motor of the main lubricating rotary vane vacuum pump (3). The pumping system according to claim 21 , wherein
The compressor (10) is driven independently of the main lubrication rotary vane vacuum pump (3) in an autonomous manner. In the pumping system in any one of Claims 21-23 ,
The compressor (10) sucks gas in the gas outlet (8) after the atmosphere or the check valve (6). In the pumping system in any one of Claims 14-24 ,
Pumping system, further comprising at least one sensor (11, 12, 13) for measuring and using at least one operating parameter to start or stop the ejector (7) . The pumping system according to claim 25 ,
Wherein the at least one operating parameter of the motor current of the main lubricating rotary vane vacuum pump (3), the space of the conduit (5) of said main lubricating rotary vane vacuum pump is limited by said check valve (6) (3) The pressure of the gas in the interior, the temperature of the gas in the space of the conduit (5) of the main lubricating rotary vane vacuum pump (3) limited by the check valve (6), or a combination of these parameters And a pressure feeding system.

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