RU2666379C2 - Method of pumping in pumping system and vacuum pump system - Google Patents

Abstract

FIELD: motors and pumps.SUBSTANCE: group of inventions relates to a pumping method in a pump system and a vacuum pump system. Pumping method in a pump system, comprising primary vacuum pump (3) with lubricated blades, having gas inlet (2) connected to vacuum chamber (1), and gas outlet (4) communicating with channel (5) upstream of gas outlet (8) of the pump system, a check valve (6) installed in the channel (5) between opening (4) and gas outlet (8), and ejector (7) installed in parallel to valve (6). Pump (3) is started to pump the gases contained in chamber (1) through opening (4), working fluid is simultaneously supplied to ejector (7), and is continuously supplied to ejector (7) until pump (3) pumps out the gases contained in chamber (1) and/or for the entire time during which pump (3) maintains a certain pressure in chamber (1).EFFECT: group of inventions is aimed at reducing the electrical power needed to obtain a vacuum in the vacuum chamber and to maintain the vacuum in said chamber to ensure a decrease in the temperature of the exhaust gases.34 cl, 3 dwg

Description

Technical field

The present invention relates to a pumping method that allows to reduce the consumption of electrical energy, as well as to improve performance in terms of flow rate and final vacuum in a pump system in which the main pump is a vacuum pump with lubricated blades. The present invention also relates to a pumping system that can be used to implement the method in accordance with the present invention.

State of the art

The general tendencies for increasing the productivity of vacuum pumps, reducing the cost of plants and energy consumption in the industry have led to significant changes in terms of improving performance, saving energy, reducing size, improving drives, etc.

Known solutions have shown that to improve the final vacuum to reduce energy consumption, it is necessary to add additional stages to multi-stage vacuum pumps such as Roots or multi-stage vacuum pumps such as Claws. For screw vacuum pumps, it is necessary to add additional screw speeds and / or increase the internal compression ratio. For vacuum pumps with lubricated vanes, it is also necessary to add one or more series-connected additional stages and increase the degree of internal compression. Well-known solutions related to pumping systems designed to improve final vacuum and increase flow rate, offer Roots type booster pumps installed at the input of primary pumps with lubricated blades. Systems of this type are cumbersome and work either with bypass valves, which creates reliability problems, or with the use of measuring, control, regulation or feedback tools. However, these means of control, regulation or feedback must be actively managed, which leads to an inevitable increase in the number of system components, its complexity and its cost.

WO 2014/012896 A2 proposes to use a relatively dry root type primary vacuum pump, an ejector, connected in parallel with the output of the primary pump to reduce the final vacuum obtained by this type of pump. In this document, the ejector is provided with a driving medium flowing through the external gas path, which, preferably, could correspond to the system used to clean the root type primary vacuum pump. SUMMARY OF THE INVENTION

The present invention is intended to provide a pumping method in a pumping system, which allows to reduce the electrical energy required to obtain a vacuum in a vacuum chamber and maintain a vacuum in this chamber, in order to reduce the temperature of the exhaust gases.

The present invention is also intended to provide a pumping system in a pumping system that allows to obtain a low pressure flow rate in excess of the low pressure flow rate that can be obtained using only one vacuum pump with lubricated vanes in the vacuum chamber.

To solve these problems, a pumping method is proposed that is implemented as part of a pumping system, the configuration of which mainly involves a primary vacuum pump with lubricated blades, having a gas inlet opening connected to a vacuum chamber, and a gas outlet opening in communication with a channel equipped with a check valve before the outlet into the atmosphere or other devices. The suction ejector is installed in parallel with this non-return valve, while its outlet enters the atmosphere or is connected to the channel of the primary pump after the non-return valve.

Such a pumping method is the subject of independent claim 1. Various preferred embodiments of the invention are also disclosed in the dependent claims.

Basically, the method consists in supplying the working fluid to the ejector and operating it continuously for the entire time, while the primary vacuum pump with lubricated blades pumps the gases contained in the vacuum chamber through the gas inlet and also during the whole time until the primary vacuum pump with lubricated blades maintains a certain pressure (for example, final vacuum) in the chamber, forcing incoming gases through its outlet.

According to the first aspect, the invention consists in the fact that the connection of the primary vacuum pump with lubricated blades and an ejector does not require special measurements and instruments (for example, pressure sensors, temperature, current, etc.), feedback or data management and calculation. Therefore, the pumping system for implementing the pumping method in accordance with the present invention contains a minimum number of components, is very simple and costs significantly less compared to existing systems. By design, an ejector built into the pumping system can operate reliably in accordance with the present pumping method. Its parameters are determined by the minimum consumption of the working fluid for the operation of the device. As a rule, it is single-stage. Its nominal flow rate is selected depending on the volume of the outlet channel of the primary vacuum pump with lubricated blades, limited by a check valve. This flow rate can be from 1/500 to 1/20 of the nominal flow rate of the primary vacuum pump with lubricated blades, but can be less or more than these values. The working fluid for the ejector may be compressed air, as well as other gases, such as nitrogen.

A check valve installed in the channel at the outlet of the primary vacuum pump with lubricated blades may be a commercially available standard element. Its parameters are calculated depending on the nominal flow rate of the primary vacuum pump with lubricated blades. In particular, it is envisaged that the check valve closes when the suction pressure of the primary vacuum pump with lubricated blades is in the range from 500 mbar absolute pressure to the final vacuum value (for example, 100 mbar).

According to another embodiment, the ejector is multi-stage. According to another embodiment, the ejector may be made of a material having enhanced chemical resistance to substances and gases commonly used in the chemical industry, in the semiconductor industry, both in the case of a single-stage ejector and in the multi-stage ejector.

Preferably, the ejector is small in size.

According to another embodiment, an ejector is integrated in the cartridge, which comprises a check valve.

According to another embodiment, an ejector is integrated in the cartridge, which contains a check valve, and this cartridge, in turn, is installed in the oil separator of the primary vacuum pump with lubricated blades.

According to another variant of the claimed method, in order to satisfy these specific requirements, the flow of gases with the pressure necessary for the operation of the ejector is controlled according to the “all or nothing” scheme. Indeed, control consists in measuring one or more parameters and in starting or stopping the ejector, depending on some predefined rules. The parameters coming from the respective sensors are, for example, the current of the vacuum pump motor with lubricated blades, the temperature or pressure of the gases in the volume of the outlet channel of the vacuum pump with lubricated blades limited by a non-return valve, or a combination of these parameters. At the beginning of the chamber emptying cycle, the pressure in it is high, for example, equal to atmospheric pressure. Given the compression in the primary vacuum pump with lubricated blades, the pressure of the gases pumped at its outlet is higher than atmospheric pressure (if the gases at the outlet of the primary pump are injected directly into the atmosphere), or higher than the pressure at the inlet of another device connected at the exit. This causes the check valve to open.

When this check valve is open, the action of the ejector is felt very weakly, since the pressure at its inlet is almost equal to the pressure at its outlet. On the other hand, when the check valve closes at a certain pressure (since the pressure in the chamber decreased at that time), the action of the ejector leads to a gradual decrease in the pressure difference between the chamber and the channel after the check valve. The pressure at the outlet of the primary vacuum pump with lubricated blades becomes equal to the pressure at the inlet of the ejector, while the pressure at its outlet remains equal to the pressure in the channel after the non-return valve. The more the ejector evacuates, the more the pressure at the outlet of the primary vacuum pump with lubricated vanes in a closed volume (limited by a closed non-return valve) decreases, and, therefore, the pressure difference between the chamber and the outlet of the primary vacuum pump with lubricated vanes decreases. This slight difference reduces internal leakage in the primary vacuum pump with lubricated blades and reduces the pressure in the chamber, which improves the final vacuum. In addition, a primary lubricated vane vacuum pump uses less and less energy to compress and produces less and less heat of compression.

In the case of control of the ejector, there is an initial starting position for the pumping system when the sensors are in a certain state or give initial values. As the primary vacuum pump with lubricated blades pumps the gases out of the vacuum chamber, parameters such as its current, temperature and gas pressure in the volume of the outlet channel begin to change and reach the threshold values detected by the sensors. This leads to the inclusion of the ejector. When these parameters return to their original ranges (except for the set values) with a delay, the ejector switches off.

According to another embodiment of the present invention, the flow of gases with the pressure necessary for the operation of the ejector, provides a compressor. It should be noted that this compressor can be driven into rotation by a primary pump with lubricated blades or, alternatively or additionally, can rotate independently, regardless of the primary pump with lubricated blades. This compressor can pump atmospheric air or gases in the gas outlet channel after the check valve. The presence of such a compressor ensures the independence of vacuum pump systems with lubricated blades from a source of compressed gas, which may correspond to some conditions of an industrial environment. The compressor can produce a gas flow with the pressure necessary for the operation of several ejectors, which are part of several vacuum pump systems, such as primary pumps with lubricated vanes. The compressor is part of the system both in the case of continuous operation of the ejector, and in the case of its control by parameters controlled by the respective sensors.

On the other hand, it is obvious that the study of the mechanical aspect is aimed at reducing the volume between the gas outlet of the primary vacuum pump with lubricated vanes and the check valve, so that the pressure in this volume decreases faster.

Brief Description of the Drawings

Distinctive features and advantages of the present invention will be more apparent from the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a diagram of a pumping system configured to implement a pumping method according to a first embodiment of the present invention.

FIG. 2 is a diagram of a pumping system configured to implement a pumping method according to a second embodiment of the present invention.

FIG. 3 is a diagram of a pumping system configured to implement a pumping method according to a third embodiment of the present invention.

Detailed Description of Embodiments

In FIG. 1 shows a pumping system SP configured to implement a pumping method according to a first embodiment of the present invention.

This pumping system SP includes a chamber 1, which communicates with the suction hole 2 of the primary vacuum pump 3 with lubricated blades. The gas outlet opening of the primary vacuum pump 3 with lubricated blades is connected to the channel 5. The pressure check valve 6 is installed in the channel 5, which after this check valve 6 is continued by the gas outlet channel 8. In the closed position, the check valve 6 allows you to get the volume 4, enclosed between it and the gas outlet of the primary vacuum pump 3. The pump system SP also contains an ejector 7 installed in parallel with the check valve 6. The suction port of the ejector is connected to the volume 4 of channel 5, and the injection hole is connected to the channel 8. The working fluid for the ejector 7 comes from the supply channel 9.

Immediately after starting the primary vacuum pump 3 with lubricated blades through the supply channel 9, the working fluid for the ejector 7 begins to pump, then the primary vacuum pump 3 with lubricated blades sucks in the chamber 1 through the channel 2 connected to its inlet and compresses them for subsequent discharge to its outlet into the channel 5 through the check valve 6. When the closing pressure of the check valve 6 is reached, this valve closes. From this moment, the pumping performed by the ejector 7 gradually leads to a decrease in pressure in the volume 4 to the value of its limiting pressure value. In parallel, the power consumed by the primary vacuum pump 3 with lubricated blades gradually decreases. This happens in a short period of time, for example, with a certain cycle in 5-10 seconds.

With proper control of the flow rate of the ejector 7 and the closing pressure of the non-return valve 6 depending on the flow rate of the primary vacuum pump 3 with lubricated blades and the volume of the chamber 1, it is also possible to shorten the time before closing the non-return valve 6 relative to the duration of the emptying cycle and, therefore, reduce the loss of working fluid during this time, the operation of the ejector 7, without affecting the pumping. In addition, these “losses”, which are negligible, are taken into account in the balance of energy consumption. On the other hand, the advantage in simplicity provides high reliability of the system, as well as the cost lower by 10% -20% compared with similar pumps equipped with a programmable machine or controller, controlled by valves, sensors, etc. In FIG. 2 illustrates a pumping system SP configured to implement a pumping method according to a second embodiment of the present invention.

Unlike the system shown in FIG. 1, the system shown in FIG. 2 further comprises a compressor 10, which provides a gas flow with a pressure necessary for the operation of the ejector 7. Indeed, this compressor 10 can suck in atmospheric air or gases in the gas outlet channel 8 after the check valve 6. Its presence ensures that the vacuum pump system is independent of the source compressed gas, which meets certain conditions of the industrial environment. The compressor 10 can be driven into rotation by a primary vacuum pump 3 with lubricated blades or its own engine, that is, completely independent of pump 3. In all cases, its energy consumption for providing the gas flow with the pressure necessary for the operation of the ejector 7 is much less (for example, about 3% -5%) in relation to the gain obtained by energy consumption by the main pump 3.

In FIG. 3 illustrates an SPP pumping system configured to implement a pumping method according to a third embodiment of the present invention.

Unlike the systems shown in FIG. 1 and 2, the system shown in FIG. 3 corresponds to a controllable pump system, which further comprises sensors 11, 12, 13 monitoring, for example, the motor current (sensor 11) of the primary vacuum pump 3 with lubricated vanes, pressure (sensor 13) gases in the volume of the outlet channel of the primary vacuum pump with lubricated vanes (limited by the check valve 6), gas temperature (sensor 12) in the volume of the outlet channel of the primary vacuum pump with lubricated vanes (limited by the check valve 6) or a combination of these pairs ametres. Indeed, when the primary vacuum pump 3 with lubricated blades begins to pump gases from the vacuum chamber 1, these parameters (in particular, its motor current, temperature and gas pressure in the volume of the output channel 4) are liable to change and reach the threshold values detected by the corresponding sensors 11, 12, 13. This causes the ejector 7 to start (after a certain delay time). When these parameters return to their original ranges (except for the set values), the ejector stops (also after a certain delay time). Of course, the controlled pump system SSP can use a distribution network or compressor as the source of compressed gas under the conditions described with reference to FIG. 2.

Of course, numerous changes can be made to the present invention with regard to its implementation. Despite the various embodiments described, it is understood that it is not possible to identify excessively all possible options. Of course, you can replace the described tool with an equivalent tool, without going beyond the scope of the present invention. All these changes are available for general knowledge of a specialist in the field of vacuum technology.

Claims (44)

1. A pumping method in a pumping system (SP, SPP) comprising: - a primary vacuum pump (3) with lubricated blades, having a gas inlet (2) connected to a vacuum chamber (1), and a gas outlet (4) communicating with a channel (5) before the gas outlet (8) of the pump system ( SP, SPP), a check valve (6) installed in the channel (5) between the gas outlet (4) and the gas outlet (8), and - an ejector (7) installed in parallel with the check valve (6), characterized in that start the primary vacuum pump (3) with lubricated blades for pumping the gases contained in the vacuum chamber (1) through the gas outlet (4); simultaneously, the working fluid is supplied to the ejector (7); and the working fluid continues to be fed into the ejector (7) for the entire time until the primary vacuum pump (3) with lubricated blades pumps out the gases contained in the vacuum chamber (1) and / or for the entire time while the vacuum pump (3) ) with lubricated blades maintains a certain pressure in the vacuum chamber (1). 2. The pumping method according to claim 1, characterized in that the outlet of the ejector (7) is connected to the channel (5) after the check valve (6). 3. The pumping method according to claim 1 or 2, characterized in that the parameters of the ejector (7) are designed to minimize the consumption of the working fluid. 4. The pumping method according to claim 1 or 2, characterized in that the nominal flow rate of the ejector (7) is selected depending on the volume of the output channel (5) of the primary vacuum pump (3) with lubricated blades, which is limited by a check valve (6). 5. The pumping method according to claim 4, characterized in that the flow rate of the ejector (7) is from 1/500 to 1/20 of the nominal flow rate of the primary vacuum pump (3) with lubricated blades. 6. The pumping method according to claim 1 or 2, characterized in that the working fluid of the ejector (7) is compressed air and / or nitrogen. 7. The pumping method according to claim 1 or 2, characterized in that the ejector (7) is multi-stage or single-stage. 8. The pumping method according to claim 1 or 2, characterized in that the non-return valve (6) closes when the suction pressure of the primary vacuum pump (3) with lubricated blades is in the range from 500 mbar absolute pressure to the final vacuum value. 9. The pumping method according to claim 1 or 2, characterized in that the ejector (7) is made of a material having high chemical resistance to substances and gases used in the chemical industry and / or in the semiconductor industry. 10. The pumping method according to claim 1 or 2, characterized in that the ejector (7) is integrated in the cartridge, which contains a check valve (6). 11. The pumping method according to claim 10, characterized in that the cartridge is installed in the oil separator of the primary vacuum pump (3) with lubricated blades. 12. The pumping method according to claim 1 or 2, characterized in that the gas flow at a pressure necessary for the operation of the ejector (7) is provided by a compressor (10). 13. The pumping method according to claim 12, characterized in that the compressor (10) is driven into rotation by a primary vacuum pump (3) with lubricated blades. 14. The pumping method according to p. 12, characterized in that the compressor (10) rotates independently, regardless of the primary vacuum pump (3) with lubricated blades. 15. The pumping method according to claim 12, characterized in that the compressor (10) draws in atmospheric air or gases in the gas outlet channel (8) after the check valve (6). 16. The pumping method according to claim 12, characterized in that at least one operating parameter is measured and used to start or stop the ejector (7). 17. The pumping method according to p. 16, characterized in that the said at least one operating parameter is the current of the engine of the primary vacuum pump 3 with lubricated blades, the gas pressure in the volume of the outlet channel of the primary vacuum pump with lubricated blades, limited by a check valve 6, temperature gases in the volume of the outlet channel of the primary vacuum pump with lubricated blades, limited by the check valve 6, or a combination of these parameters. 18. A pumping system (SP, SPP), comprising: - a primary vacuum pump (3) with lubricated vanes having a gas inlet (2) connected to a vacuum chamber (1) and a gas outlet (4) communicating with a channel (5) before the gas outlet (8) of the system (SP ) vacuum pumps, a check valve (6) installed in the channel (5) between the gas outlet (4) and the gas outlet (8), and - an ejector (7) installed in parallel with the check valve (6), characterized in that the ejector (7) is configured to receive power from the working fluid all the time, while the primary vacuum pump (3) with lubricated blades pumps out the gases contained in the vacuum chamber (1), and / or throughout the whole time, while the vacuum pump (3) with lubricated blades maintains a certain pressure in the vacuum chamber (1). 19. A pump system according to claim 18, characterized in that the outlet of the ejector (7) is connected to the channel (5) after the check valve (6). 20. The pump system according to p. 18 or 19, characterized in that the parameters of the ejector (7) are designed for minimum consumption of the working fluid. 21. A pump system according to claim 18 or 19, characterized in that the nominal flow rate of the ejector (7) is selected depending on the volume of the outlet channel (5) of the primary vacuum pump (3) with lubricated blades, which is limited by a check valve (6). 22. A pump system according to claim 21, characterized in that the flow rate of the ejector (7) is from 1/500 to 1/20 of the nominal flow rate of the primary vacuum pump (3) with lubricated blades. 23. A pump system according to claim 18 or 19, characterized in that the working fluid of the ejector (7) is compressed air and / or nitrogen. 24. A pump system according to claim 18 or 19, characterized in that the ejector (7) is multi-stage or single-stage. 25. A pump system according to claim 18 or 19, characterized in that the check valve (6) closes when the suction pressure of the primary vacuum pump (3) with lubricated blades is in the range from 500 mbar absolute pressure to the final vacuum value. 26. A pump system according to claim 18 or 19, characterized in that the ejector (7) is made of a material having enhanced chemical resistance to substances and gases used in the chemical industry and / or in the semiconductor industry. 27. A pump system according to claim 18 or 19, characterized in that the ejector (7) is integrated in the cartridge, which contains a check valve (6). 28. The pump system according to p. 27, characterized in that the cartridge is installed in the oil separator of the primary vacuum pump with lubricated blades. 29. A pump system according to claim 18 or 19, characterized in that it comprises a compressor (10), which provides a gas flow at a pressure necessary for the operation of the ejector (7). 30. A pump system according to claim 18, characterized in that the compressor (10) is driven by a primary vacuum pump (3) with lubricated blades. 31. A pump system according to claim 29, characterized in that the compressor (10) rotates independently, regardless of the primary vacuum pump (3) with lubricated blades. 32. A pump system according to claim 29, characterized in that the compressor (10) draws in atmospheric air or gases in the gas outlet channel (8) after the check valve (6). 33. A pump system according to claim 18 or 19, characterized in that it comprises at least one sensor (11, 12, 13) for measuring at least one operating parameter and for using it to start or stop the ejector (7). 34. The pump system according to p. 33, characterized in that the said at least one operating parameter is the motor current of the primary vacuum pump 3 with lubricated vanes, the gas pressure in the volume of the outlet channel of the primary vacuum pump with lubricated vanes limited by a check valve 6, temperature gases in the volume of the outlet channel of the primary vacuum pump with lubricated blades, limited by the check valve 6, or a combination of these parameters.

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