Vacuum pumping system with multiple positive displacement vacuum pumps and method for operating a vacuum pumping system

Abstract

The present invention relates to a vacuum pumping system having a plurality of positive displacement vacuum pumps and to a method for operating a vacuum pumping system. The present invention relates to a vacuum pumping system (100) having a plurality of positive displacement vacuum pumps (20, 30) and, more particularly, a plurality of positive displacement vacuum pumps working in parallel, and to a method for operating such a vacuum pumping system. The vacuum pumping system (100) comprises a management unit (90) which controls synchronously all the positive displacement vacuum pumps of the vacuum pumping system and thus allows to check the possible contamination risks of the vacuum pumping system and, if necessary, to carry out the necessary corrective actions without the need to make any modifications to the configuration of the vacuum pumping system.

Description

Technical Field

[0001] The present invention relates to a vacuum pumping system having multiple positive displacement vacuum pumps, and more particularly multiple positive displacement vacuum pumps operating in parallel.

[0002] The present invention also relates to a method for operating a vacuum pumping system having multiple positive displacement vacuum pumps, and more particularly multiple positive displacement vacuum pumps operating in parallel and / or connected to vacuum chambers in communication with each other. Background Technology

[0003] Vacuum pumps are used to achieve a vacuum state, that is, to empty a chamber (the so-called "vacuum chamber") and establish a sub-atmospheric pressure state within it. Many different types of vacuum pumps with different structures and operating principles are known, and a specific vacuum pump must be selected each time based on the needs of a particular application, that is, based on the degree of vacuum to be achieved in the corresponding vacuum chamber.

[0004] Positive displacement vacuum pumps displace gas from a sealed area to the atmosphere or downstream pump stages.

[0005] Positive displacement pumps are highly efficient and cost-effective in generating low vacuum conditions. For this reason, they can be used as the main pump in vacuum systems, but they are often used as pressure pumps for other pumps, such as turbomolecular pumps.

[0006] Unfortunately, in some cases, positive displacement vacuum pumps, such as rotary vane pumps or vortex pumps, can contaminate the vacuum system in which they are installed.

[0007] Rotary vane vacuum pumps can be considered through non-limiting examples.

[0008] Figures 1 and 2 schematically illustrate a vacuum pumping device 150, which includes a conventional rotary vane vacuum pump 110 and an associated motor 140.

[0009] As shown in Figures 1 and 2, a conventional rotary vane vacuum pump 110 typically includes a housing 112 receiving a pump body 114, within which a stator defines a cylindrical pumping chamber 116 surrounding and defining the pump body 114. The pumping chamber 116 houses a cylindrical rotor 118, which is eccentrically positioned about the axis of the pumping chamber 116; one or more radially movable radial vanes 120 (two in the example shown in Figure 2) are mounted on the rotor 118 and held against the wall of the pumping chamber 116, for example by springs 122.

[0010] During operation of vacuum pump 110, gas flows from vacuum chamber through pump inlet port 124 and is delivered to pumping chamber 116 via suction line 126, where it is propelled and thus compressed by vanes 120, and then discharged via discharge line 128 terminating at the corresponding outlet port 130.

[0011] An appropriate amount of oil is introduced from an oil tank (not shown) into the housing 112 to serve as a coolant and lubricating fluid. In the example shown in Figure 2, for example, the inner housing 114 is immersed in an oil tank 132.

[0012] In order to drive the rotor 118 of the vacuum pump, the vacuum pumping device 150 also includes a motor 140, and the pump rotor 118 is mounted to a rotating shaft driven by the motor.

[0013] As mentioned above, in rotary vane vacuum pumps, oil is used to lubricate and cool the pump's moving parts. In this type of pump, oil is also used as a sealant to provide a seal between areas under different pressures.

[0014] There is a risk of oil vapor causing backflow and contamination of the vacuum chamber emptied by the vacuum pump at the inlet of the vacuum pump.

[0015] This risk is even higher in vacuum pumping systems in which there are two or more rotary vane vacuum pumps operating in parallel and / or connected to vacuum chambers that are interconnected.

[0016] Indeed, in such a complex vacuum pumping system, if one of the rotary vane vacuum pumps stops due to failure, the other rotary vane vacuum pump in the system can draw oil vapor from the inlet of the stopped pump. Therefore, the drawn-in oil is transferred through the vacuum chamber to which the pumps are connected, ultimately contaminating the entire vacuum pumping system.

[0017] To prevent contamination of the vacuum chamber, positive displacement vacuum pumps, such as rotary vane vacuum pumps, can be equipped with protective devices to prevent pressure rise and / or oil backflow into the vacuum chamber when the pump is shut down. In this way, the vacuum chamber can be completely isolated from the positive displacement vacuum pump.

[0018] In the case of a vacuum pumping system with multiple positive displacement vacuum pumps operating in parallel, each positive displacement vacuum pump is equipped with its own protection device, such as a backflow prevention valve, which prevents backflow into the vacuum chamber, thereby suppressing the risk of contamination of the vacuum chamber.

[0019] However, when two or more positive displacement vacuum pumps are connected in parallel to the same vacuum chamber, the anti-backflow valve mounted on each individual pump may fail under certain operating conditions, exposing the vacuum chamber to contamination.

[0020] To avoid the risk of contamination in all situations (during normal operation and malfunction), vacuum pumping with an external system or device can be installed. For example, an isolation valve can be installed for each positive displacement vacuum pump.

[0021] However, this solution is not attractive because it increases the number of parts and the complexity of the vacuum pumping system, and involves additional costs.

[0022] In previous analytical instruments (mass spectrometers) that relied on vacuum pumping systems and were operated by the applicant, multiple vacuum pumps were in fluid communication with the vacuum chamber of the vacuum pumping system, for example, through T-connectors that shared a common vacuum port with the vacuum chamber. Contamination of these systems due to vacuum pump failure was unknown. Recent developments by the applicant have resulted in the need for vacuum pumps that are separately connected to the vacuum chamber, creating fluid paths between the vacuum pumps. While the vacuum pumps operate in a conventional manner, the inventors have unexpectedly discovered the contamination problem of such systems. Therefore, the inventors recognized the need for a system and method for operating multiple vacuum pumps that are separately connected to the vacuum chamber, reducing the risk of vacuum chamber contamination.

[0023] The main objective of this invention is to provide a vacuum pumping system that suppresses the risk of contaminating the vacuum chamber while avoiding the introduction of additional external devices or systems.

[0024] Another object of the present invention is to provide a method for operating a vacuum pumping system that allows the risk of contaminating the vacuum chamber to be avoided without implementing any additional external devices or systems.

[0025] These and other objectives are achieved by the vacuum pumping system and the method for operating the vacuum pumping system as described in the appended claims. Summary of the Invention

[0026] The inventors have discovered that when two or more vacuum pumps are connected to a vacuum chamber, i.e., when at least one vacuum pump is connected to the vacuum chamber through separate vacuum ports in fluid communication with the vacuum chamber, the vacuum chamber of the vacuum pumping system may become contaminated. Under certain pump operating conditions, one vacuum pump in the vacuum pumping system may cause backflow through another vacuum pump, thereby drawing contaminated gas into the vacuum chamber and thus contaminating it.

[0027] The vacuum pumping system according to the invention comprises a plurality of positive displacement vacuum pumps that operate in parallel, i.e., are designed to be connected to the same vacuum chamber and / or to vacuum pumping chambers that are connected to each other.

[0028] The vacuum pumping system also includes a management unit that synchronously controls all positive displacement vacuum pumps in the system. Synchronous adjustment of the vacuum pump operating parameters prevents one or more vacuum pumps from potentially flowing back into the shared vacuum chamber.

[0029] More specifically, the management unit is configured as follows:

[0030] - Identify one or more operating parameters that are associated with the risk of contamination of the vacuum pumping system by the positive displacement vacuum pump;

[0031] - Set a threshold or threshold state for each of the parameters;

[0032] - All positive displacement vacuum pumps in the vacuum pumping system are controlled by detecting the identification parameters of each pump and by comparing the current value or state of the identification parameters with the corresponding threshold or threshold state for each pump.

[0033] In this embodiment, the management unit can be configured as follows:

[0034] - Monitor one or more operating parameters of each of the vacuum pumps in the parallel vacuum pumping system;

[0035] - Identify, based on monitoring, the state in which at least one of the pumps is operating at a threshold level that indicates the risk of potential backflow from the vacuum pumping system or the state of potential backflow from the vacuum pumping system.

[0036] - Based on the identified state, synchronize the vacuum pumps of the vacuum pumping system to prevent backflow.

[0037] In some aspects, synchronized operation may include increasing the operating speed of one or more vacuum pumps that are underpumping relative to one or more other vacuum pumps. In some aspects, synchronized operation may include decreasing the operating speed of one or more vacuum pumps that are overpumping relative to one or more other vacuum pumps. In some aspects, one or more operating parameters include a measure of pump speed / frequency.

[0038] The management unit is also configured to synchronously perform correction actions on multiple positive displacement pumps (preferably all of the positive displacement vacuum pumps) of the vacuum pumping system when the detection value of one or more identification parameters exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state.

[0039] More specifically, the management unit is also configured to synchronously shut down multiple positive displacement pumps (preferably all of the positive displacement vacuum pumps) of the vacuum pumping system when the detection value of one or more identification parameters exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state.

[0040] The management unit can also be configured to trigger an alarm when the detection value of one or more identification parameters exceeds the corresponding threshold or when the detection status of one or more identification parameters is inconsistent with the corresponding threshold status.

[0041] Advantageously, the present invention provides synchronous management of multiple positive displacement vacuum pumps (preferably all of the positive displacement vacuum pumps) in a vacuum pumping system, such that the failure of a single vacuum pump is immediately considered not only on the failed vacuum pump but also on the other vacuum pumps in the vacuum pumping system, thereby effectively preventing any risk of contamination of the vacuum pumping system itself.

[0042] The management unit can simultaneously control all positive displacement vacuum pumps in the vacuum pumping system.

[0043] Alternatively, the management unit can control all positive displacement vacuum pumps of the vacuum pumping system sequentially or in a predetermined order.

[0044] The management unit can continuously control the positive displacement vacuum pump of the vacuum pumping system.

[0045] Alternatively, the management unit can control the positive displacement vacuum pump of the vacuum pumping system in a discrete manner at predetermined time intervals.

[0046] Advantageously, the management unit of the vacuum pumping system according to the invention allows for the inspection of potential contamination risks of the vacuum pumping system and, when necessary, the correction action without requiring any modification to the construction of the vacuum pumping system, i.e., without any additional components such as sensors, vacuum gauges, isolation valves, etc.

[0047] As is known, although positive displacement vacuum pumps can be directly connected to a vacuum chamber, they are more often used as backing pumps for high vacuum pumps, such as turbomolecular vacuum pumps.

[0048] Accordingly, the vacuum pumping system according to the invention may further include one or more high vacuum pumps (e.g., one or more turbomolecular pumps), and the management unit may be configured to control the high vacuum pumps for the purpose of improving their service life.

[0049] For example, in the case of turbomolecular vacuum pumps, failure of the turbomolecular vacuum pump can be predicted by checking parameters such as power, frequency and temperature of the bearings.

[0050] Furthermore, in the event of a failure of the positive displacement vacuum pump, which acts as the backing pump for the turbomolecular vacuum pump, the turbomolecular vacuum pump itself will operate in a critical state. In this situation, by synchronously checking the parameters of all vacuum pumps in the vacuum pumping system, the management unit can immediately shut down the turbomolecular vacuum pump, thereby preventing damage and extending its service life.

[0051] In some embodiments of the vacuum pumping system, a management unit may operate to initiate a startup sequence that synchronously and sequentially verifies the operation of the vacuum pumps to confirm that identified operating parameters are maintained within the expected threshold or band before increasing the pumping speed to induce an operating vacuum in the vacuum chamber of the vacuum pumping system. In some aspects, the vacuum pumping system may include one or more vacuum pumps in multiple groups, each of which is in communication with a vacuum chamber of the vacuum pumping system. Anti-backflow valves may isolate each of the groups of one or more vacuum pumps from the vacuum chamber. During operation, the management unit may operate to activate one or more pumps in a first group to operate at a low startup level, while one or more pumps in another group remain inactive. The inactive pumps do not apply suction to their respective backflow valves, causing the backflow valves to remain closed, thereby preventing backflow. The management unit monitors one or more operating parameters of the first group of pumps to identify that the first group of pumps is operating as expected. After confirming the expected operation of the first group of pumps, the management unit activates one or more pumps in the next group. The operating parameters of the next group of pumps are set to synchronize the operation of the next group of pumps with the previously activated group of pumps to avoid backflow when the backflow valve opens and the first group of pumps is connected to the second group of pumps. In some aspects, other groups of pumps can be activated, monitored, and synchronized similarly to avoid backflow. In some embodiments of the vacuum pumping system, a management unit can operate to monitor the operation of the vacuum pumps, thereby confirming that they are operating synchronously by monitoring the pumps' operating parameters to confirm that they are maintained within a desired threshold or band for a given operating state. In some aspects, the vacuum pumping system may include one or more vacuum pumps in multiple groups, each of which is in communication with a vacuum chamber of the vacuum pumping system. Anti-backflow valves can disconnect each of the one or more groups of vacuum pumps from the vacuum chamber. During operation, the management unit can operate to monitor one or more operating parameters of the pumps to identify that they are operating as expected. When the management unit detects that a pump is operating outside of its expected state, for example by detecting that the pump's operating parameters meet or deviate from a desired threshold, the management unit can operate to synchronize the operation of the pumps to avoid operating states of other pumps that would cause backflow through one or more pumps in the system.

[0052] Accordingly, the method for operating a vacuum pumping system comprising a plurality of positive displacement vacuum pumps according to the present invention includes the following steps:

[0053] - Identify one or more operating parameters related to contamination of the vacuum pumping system by the positive displacement vacuum pump;

[0054] - Set a threshold or threshold state for each of the parameters;

[0055] - Parameters are detected and identified for each positive displacement vacuum pump;

[0056] - For each positive displacement vacuum pump, the detected value or state of the identified parameter is compared with the corresponding threshold or threshold state.

[0057] The method further includes a step of synchronously performing a correction action on multiple positive displacement pumps (preferably all of the positive displacement vacuum pumps) of the vacuum pumping system when the detection value of one or more identification parameters exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state.

[0058] More specifically, the method preferably includes the step of synchronously shutting down multiple positive displacement pumps (preferably all of the positive displacement vacuum pumps) of the vacuum pumping system when the detection value of one or more identification parameters exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state.

[0059] In addition, the method may also include a step of triggering an alarm when the detection value of one or more identification parameters exceeds the corresponding threshold or when the detection state of one or more identification parameters is inconsistent with the corresponding threshold state.

[0060] For all positive displacement vacuum pumps in a vacuum pumping system, testing and comparison steps can be performed simultaneously.

[0061] Alternatively, the detection and comparison steps can be performed sequentially or in a predetermined order on the positive displacement vacuum pump of the vacuum pumping system.

[0062] The detection and comparison steps can be performed in a continuous manner.

[0063] Alternatively, the detection and comparison steps can be performed discretely at predetermined time intervals.

[0064] In some embodiments, a vacuum pumping system is provided. The vacuum pumping system may include at least one interconnected vacuum chamber and a plurality of vacuum pumps, each of the plurality of vacuum pumps being connected to the at least one vacuum chamber. A management unit may be configured to control the operation of the plurality of vacuum pumps and monitor one or more operating parameters of the plurality of vacuum pumps. Based on the monitoring, the management unit may identify anticipated pumping mismatches between one or more of the plurality of vacuum pumps based on one or more operating parameters. In some aspects, the at least one interconnected vacuum chamber of the vacuum pumping system comprises a plurality of interconnected vacuum chambers, wherein one of the plurality of vacuum pumps is separately connected to a first vacuum chamber of the plurality of vacuum chambers, and another of the plurality of vacuum pumps is separately connected to another of the plurality of vacuum chambers. In some aspects, at least one of the vacuum chambers is in communication with the atmosphere. In some respects, the management unit can also operate to activate multiple vacuum pumps by: activating a first vacuum pump among the multiple vacuum pumps, monitoring one or more operating parameters of the first vacuum pump, confirming based on the monitoring that the first vacuum pump is providing the expected pumping, such as by operating within the expected pumping speed range, and based on the confirmation, activating a second vacuum pump (among the multiple vacuum pumps); monitoring one or more operating parameters of the first and second vacuum pumps, while synchronizing the operation of the first and second vacuum pumps to match the expected pumping speed of the first and second vacuum pumps, thereby preventing backflow from one of the multiple vacuum pumps into at least one interconnected vacuum chamber.

[0065] In some embodiments of the above-described vacuum pumping system or method, one or more operating parameters may be selected from the group consisting of pump speed or frequency, power, current, voltage, and temperature of pump components. Attached Figure Description

[0066] The following description, with reference to the accompanying drawings, illustrates some preferred embodiments of the invention by way of non-limiting examples, wherein:

[0067] Figure 1 is a longitudinal cross-sectional view of a portion of a prior art vacuum pump;

[0068] Figure 2 is a cross-sectional view of a portion of a prior art vacuum pump similar to Figure 1;

[0069] - Figures 3a-3c This is a schematic diagram of a possible configuration of the vacuum pumping system according to the present invention;

[0070] - Figure 4 This is a flowchart illustrating the operation of the management unit of the vacuum pumping system according to the present invention in a first operating state;

[0071] - Figure 5This is a flowchart illustrating the operation of the management unit of the vacuum pumping system according to the present invention in a second operating state;

[0072] - Figure 6 This is a flowchart illustrating the operation of the management unit of the vacuum pumping system according to the present invention in a third operating state;

[0073] - Figure 7 This is a flowchart illustrating the operation of the management unit of the vacuum pumping system according to a variant of the present invention in a third operating state;

[0074] - Figure 8 This is a schematic diagram illustrating an embodiment of a vacuum pumping system according to various aspects of the present invention in an exemplary mass spectrometer system;

[0075] - Figure 9 This is a block diagram illustrating a computer system on which embodiments of the present teachings may be implemented according to various aspects of the applicant's teachings. Detailed Implementation

[0076] The present invention can be advantageously applied to vacuum pumping systems comprising two or more positive displacement pumps operating in parallel and / or connected to interconnected vacuum chambers.

[0077] Figures 3a-3c Some exemplary, non-limiting examples of the construction of such a vacuum pumping system 100 are shown.

[0078] However, it should be understood that the present invention can be applied to vacuum pumping systems that include multiple positive displacement vacuum pumps of any type and structure and may also include one or more high vacuum pumps of any type and structure.

[0079] Figure 3a A first exemplary embodiment of the vacuum pumping system 100 of the present invention is shown, wherein two positive displacement vacuum pumps 20, 30 are respectively connected to the same vacuum chamber 60, i.e., they operate in parallel, but are connected to the vacuum chamber 60 through separate vacuum ports. Figure 3a In the middle, the vacuum chamber 60 is fluidly connected between the vacuum pumps 20 and 30.

[0080] Figure 3b A second exemplary embodiment of the vacuum pumping system 100 of the present invention is shown, wherein a first positive displacement vacuum pump 20 is connected to a first vacuum chamber 60, and a second positive displacement vacuum pump 30 is connected to a second vacuum chamber 70, the vacuum chambers 60 and 70 being in fluid communication with each other. Similar to... Figure 3a Vacuum chambers 60 and 70 form a fluid connection between vacuum pumps 20 and 30.

[0081] Figure 3cA third exemplary embodiment of the vacuum pumping system 100 of the present invention is shown, wherein a first positive displacement vacuum pump 20 is connected to a first vacuum chamber 60, and a second positive displacement vacuum pump 30 operates as a backing pump (e.g., a turbomolecular vacuum pump) for a high vacuum pump 40, which in turn is connected to a second vacuum chamber 70, the vacuum chambers 60 and 70 being in fluid communication with each other. Similar to... Figure 3a Vacuum chambers 60 and 70 and high vacuum pump 40 form a fluid connection between vacuum pumps 20 and 30.

[0082] exist Figures 3a-3b In the exemplary vacuum pumping system, the first and second positive displacement vacuum pumps can be grease-lubricated pumps, such as the first and second rotary vane vacuum pumps, which have the overall structure shown in Figures 1 and 2.

[0083] However, positive displacement vacuum pumps with different structures and operations can be selected as the first and second positive displacement pumps in the vacuum pumping system.

[0084] More specifically, different types of vacuum pumps can be selected as the first and second positive displacement pumps in the vacuum pumping system: for example, one of the positive displacement vacuum pumps can be a grease-lubricated pump, such as a rotary vane vacuum pump, which has the overall structure shown in Figures 1 and 2, while the other can be a positive displacement vacuum pump with a different structure.

[0085] It will be apparent to those skilled in the art that, in all the embodiments shown, failure of one of the first rotary vacuum pump 20 and the second rotary vacuum pump 30 could result in a risk of contaminating the vacuum pumping system.

[0086] In all the configurations shown, for example, if the first rotary vane vacuum pump 20 stops due to failure when the vacuum pumping system is started, and the second rotary vane vacuum pump 30 starts, the oil vapor at the inlet of the first rotary vane vacuum pump 20 will be pumped by the second rotary vane vacuum pump 30 and drawn into the vacuum chamber 60 or vacuum chambers 60, 70, thus contaminating the vacuum pumping system.

[0087] In some arrangements, anti-backflow valves may be introduced between vacuum pumps 20, 30 and vacuum chambers 60, 70. When vacuum pumps 20, 30 are not operating, the anti-backflow valves can close to prevent backflow into vacuum chambers 60, 70. When vacuum pumps 20, 30 are actuated, the anti-backflow valves open under the vacuum generated by vacuum pumps 20, 30. The inventors have determined that, under certain operating conditions, the anti-backflow valves can open upon actuation of their associated pumps 20, 30, but under certain flow conditions in vacuum chambers 60, 70, they may cause backflow from pumps 20, 30 to vacuum chambers 60, 70. These operating conditions may typically occur during uncoordinated startup, defective operation, or uncoordinated shutdown of vacuum pumps 30, 40. Backflow from pumps 20, 30 to vacuum chambers 60, 70 can lead to contamination and inaccurate measurements by analytical instruments operating within the vacuum system 100.

[0088] In some embodiments, one of the vacuum chambers 60, 70 of the vacuum system 100 may be in communication with the atmosphere, for example, through a port. In these embodiments, the vacuum chambers 60, 70 are maintained at different operating pressures during operation, and fluid is continuously drawn in through the port by the operation of the vacuum pumps 20, 30. When operating on these embodiments, it has been found that asynchronous operation of the vacuum pumps 20, 30 generates unexpected flow conditions, which may cause backflow from one or more of the vacuum pumps 20, 30 into the vacuum chambers 60, 70.

[0089] The above is Figures 3a-3c In all exemplary embodiments shown and described, the vacuum pumping system 100 also includes a management unit 90.

[0090] The management unit 90 is configured to control both rotary vane vacuum pumps 20 and 30 synchronously. By controlling the vacuum pumps 20 and 30 synchronously, backflow from at least one of the vacuum pumps 20 and 30 into the vacuum chambers 60 and 70 is avoided.

[0091] In detail, the management unit 90 is designed to check for potential pollution risks and, if a risk is identified, to perform necessary corrective actions to prevent such pollution from occurring.

[0092] For this purpose, management unit 90:

[0093] - Identify one or more operating parameters related to contamination of the vacuum pumping system by the positive displacement vacuum pump;

[0094] - Set a threshold or threshold state for each of the parameters;

[0095] -Detect the identification parameters of each positive displacement vacuum pump 20, 30;

[0096] - For each positive displacement vacuum pump 20, 30, compare the current value or state of the identified parameter with the corresponding threshold or threshold state;

[0097] - If the detected value of one or more identification parameters in the positive displacement vacuum pump exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state, the positive displacement vacuum pumps 20 and 30 are corrected synchronously.

[0098] Preferably, when the detection value of one or more identification parameters in one or more of the positive displacement vacuum pumps exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state, the management unit 90 synchronously shuts down both positive displacement vacuum pumps 20 and 30.

[0099] Preferably, if the detection value of one or more identification parameters of one or more positive displacement vacuum pumps exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state, the management unit 90 also triggers an alarm.

[0100] By acting synchronously on the positive displacement pumps of the vacuum pumping system, and preferably on all positive displacement pumps of the vacuum pumping system, the management unit 90 of the vacuum pumping system according to the invention allows for the effective prevention of any contamination risk resulting from the operation of a positive displacement vacuum pump after the failure of another positive displacement vacuum pump in the vacuum pumping system, or allows for the slowing and shutdown of the positive displacement vacuum pump in a manner synchronized with the slowing and shutdown of the failed pump or a pump operating outside its expected operating parameters.

[0101] Furthermore, this effect can be achieved through the present invention without the need to introduce any additional safety components.

[0102] refer to Figure 3c In an exemplary configuration, the management unit 90 can also be configured to control the turbomolecular vacuum pump 40.

[0103] More specifically, if the detection value of one or more identification parameters in one or more of the positive displacement vacuum pump exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state, the management unit 90 can also be configured to perform a correction action on the turbomolecular vacuum pump 40.

[0104] For example, if the detection value of one or more identification parameters in one or more of the positive displacement vacuum pump exceeds the corresponding threshold or the detection state of one or more identification parameters is inconsistent with the corresponding threshold state, the management unit 90 can also be configured to shut down the turbomolecular vacuum pump 40.

[0105] Figures 4-7The flowchart illustrates, by way of non-limiting example, the operation of the management unit 90 of the vacuum pumping system according to the present invention in a possible operable state of the vacuum pumping system itself.

[0106] exist Figures 4-7 In, it is shown that there is a basis Figure 3a The operation of the management unit of the vacuum pumping system is governed by its construction. However, for vacuum pumping systems with different constructions, such as... Figure 3b and Figure 3c The ones shown can also be used to draw similar flowcharts.

[0107] exist Figures 4-6 In the flowchart, pump frequency is primarily used as a parameter to control the operation of the positive displacement vacuum pumps 20 and 30 in the vacuum pumping system. The operating frequency of pumps 20 and 30 is selected corresponding to the desired pressure within vacuum chambers 60 and 70. When the system includes multiple vacuum pumps 20 and 30 that are separately connected to vacuum chambers 60 and 70, the pressure in each of the vacuum chambers 60 and 70 depends on the vacuum pump 20 or 30 operating at the selected operating frequency for that pump. Therefore, monitoring the pump frequency is a useful parameter for synchronizing pumps 20 and 30 to achieve the desired pressure range in each of the vacuum chambers 60 and 70.

[0108] However, it is clear that this choice should not be construed as a limitation: a positive displacement vacuum pump is a complex device in which various operating parameters are closely related, such as the power absorbed by the pump, current, voltage, and temperature of the pump components; any of these parameters, along with others, can be used as control parameters. In some embodiments, operating parameters may include measurements of the environment of the vacuum pumping system, such as the pressure in each of the vacuum chambers 60, 70, the flow rate through the connection between the pumps 20, 30 and the vacuum chambers 60, 70, or some combination of such factors. Furthermore, in more complex control algorithms, several parameters may be used to check the operation of the positive displacement vacuum pump.

[0109] Figure 4 The operation of the management unit 90 in a first operating state of the vacuum pumping system is illustrated by way of a non-limiting example, which corresponds to the normal operating state of the vacuum pumping system 100.

[0110] In this operational state, the rotary vane vacuum pumps 20 and 30 operate at the nominal frequency, and the pressure in the vacuum chambers 60 and 70 matches the expected operating pressure and flows into each of the vacuum pumps 20 and 30.

[0111] Management unit 90 identifies two parameters related to the potential contamination risk of the vacuum pumping system:

[0112] - First parameter: Rotary vane vacuum pump failure;

[0113] - Second parameter: Pump frequency of the rotary vane vacuum pump.

[0114] The first parameter can present two states: yes or no. The management unit 90 sets "no" to a state where there is no risk of pollution, and "yes" to a state where there is a risk of pollution.

[0115] The second parameter can present a certain range of values, while the management unit 90 sets a minimum threshold value; if the value is lower than the minimum threshold value, there is a risk of contamination.

[0116] Therefore, in this first operable state, the management unit 90 operates as follows:

[0117] - Rotary vane vacuum pumps 20 and 30 operate at the nominal frequency (step 101);

[0118] - The management unit 90 checks the actual frequency of pumps 20 and 30 and compares the actual frequency with the nominal frequency for each pump (step 103);

[0119] - If the actual frequency is equal to the nominal frequency, no correction action is performed, and a new control cycle is started;

[0120] -If not, the management unit checks for each pump whether the pump is being derated (step 105);

[0121] -If any of the pumps is being derating, the management unit 90 further detects the pump frequency of each pump 20, 30 and compares the detected frequency with a minimum threshold (step 107).

[0122] - If the frequency detected for the two pumps 20 and 30 is higher than the minimum threshold, the management unit 90 triggers an alarm, indicating that the pump frequency of one of the pumps is different from the nominal frequency (step 109);

[0123] -If the detection frequency for one of pumps 20 and 30 is lower than the minimum threshold, the management unit 90 detects a dangerous situation and triggers a synchronous shutdown procedure for both pumps 20 and 30 (step 111).

[0124] -If there is no pump derating, the management unit 90 further checks whether one of the pumps has failed (step 113);

[0125] - If any of the pumps fails, the management unit 90 detects the danger and triggers the synchronous shutdown procedure of the two pumps 20 and 30 (step 115);

[0126] - If there is no pump failure, no corrective action will be taken and a new control cycle will begin.

[0127] The aforementioned control cycle can be performed continuously or at predetermined time intervals.

[0128] Figure 5 The operation of the management unit 90 in a second operating state of the vacuum pumping system is shown by way of non-limiting example, which corresponds to the discharge stage when shut down.

[0129] In this operational state, rotary vane vacuum pumps 20 and 30 will typically stop and the anti-backflow valve (ASBV) will close. This ensures that the vacuum system will not be contaminated unless the ASBV malfunctions. Therefore, the risk of contamination during the discharge phase is relatively low.

[0130] In this state, management unit 90 identifies a single parameter related to the potential contamination risk of the vacuum pumping system, namely that the rotary vacuum pump is still operating.

[0131] This parameter can present two states: yes or no. The management unit 90 sets "no" to a state where there is no risk of pollution, and "yes" to a state where there is a risk of pollution.

[0132] Therefore, in this second operational state, the management unit 90 operates as follows:

[0133] -Emissions phase begins (step 201);

[0134] - Simultaneously shut down rotary vane vacuum pumps 20 and 30 (step 203);

[0135] - Management unit 90 checks whether each pump has stopped (step 205);

[0136] -If both pumps 20 and 30 have stopped, the management unit does not perform any correction action, and the vacuum pumping system is left exposed to air;

[0137] - If not, the management unit 90 triggers an alarm to instruct the operator that one or both of the vacuum pumps 20 and 30 must be manually shut down.

[0138] Figure 6 This is a flowchart showing the operation of the management unit 90 in the third operating state of the vacuum pumping system, which corresponds to the start-up of the vacuum pumping system.

[0139] Given the risk of contamination in the vacuum pumping system, the startup phase is the most critical phase because the ASBV of pumps 20 and 30 is open under atmospheric pressure.

[0140] If, during the start-up phase, one of pumps 20 and 30 reaches the target frequency, while the other pump 30 or 20 stops for any reason, the operating pump can draw oil vapor from the other pump 20 through the vacuum chamber 60. The end result is that the vacuum pumping system becomes contaminated.

[0141] During the startup phase, the pump starts at its minimum frequency and gradually increases to the nominal frequency. During this gradual frequency increase, the difference in pumping speed among pumps connected to the same vacuum chamber must be kept to a minimum. In embodiments employing pumps of different sizes or models, the pumping speed of each pump may differ during synchronized operation; however, their effective pumping speed in the vacuum is matched to avoid one pump drawing backflow through the other. The pumping speed, or effective pumping speed, can be reflected by one or more operating parameters, including, for example, pump frequency, power extraction, etc.

[0142] In this state, management unit 90 identifies two parameters related to the potential contamination risk of the vacuum pumping system:

[0143] - First parameter: Failure of the rotary vane vacuum pump;

[0144] - Second parameter: The difference between the pumping frequency of the first rotary vane vacuum pump 20 and the pumping frequency of the second rotary vane vacuum pump 30 at a specific delay after the rotary vane vacuum pump has been turned on.

[0145] Management unit 90 sets a maximum threshold for the difference in pump frequencies.

[0146] Therefore, in this third operational state, the management unit 90 operates as follows:

[0147] - Startup phase begins (step 301);

[0148] -Make the frequency of the rotary vane vacuum pumps 20 and 30 reach the first check value (step 303);

[0149] - The management unit checks whether the two pumps have reached the first check value after the first predetermined time interval, that is, whether the difference between the pump frequencies is within the set threshold (step 305);

[0150] - If not, the management unit checks whether any of the pumps is malfunctioning (step 307); if yes, the management unit shuts down both pumps 20 and 30 (step 309); if no, the pump frequency continues to gradually increase and a new check is performed.

[0151] -If so, the frequency is gradually increased and continued until both pumps reach the second check value (step 311);

[0152] - The management unit checks whether the two pumps have reached the second check value after the third predetermined time interval, that is, whether the difference between the pump frequencies is within the set threshold (step 313);

[0153] - If not, the management unit checks whether any of the pumps has failed (step 315), and further checks whether the frequency of any of the pumps has dropped below the first check value (step 317); if one of these states is met, the management unit shuts down both pumps 20 and 30 (step 309); if these states are not met, the pump frequency continues to gradually increase, and a new check is performed.

[0154] -If so, the frequency continues to increase gradually until both pumps reach the final check value corresponding to the nominal frequency (step 319);

[0155] - The management unit checks whether the two pumps have reached the final check value after the fourth predetermined time interval, that is, whether the difference between the pump frequencies is within the set threshold (step 321);

[0156] - If not, the management unit checks whether any of the pumps has failed (step 323), and further checks whether the frequency of any of the pumps has dropped below the second check value (step 325); if one of these states is met, the management unit shuts down both pumps 20 and 30 (step 327); if these states are not met, the pump frequency continues to gradually increase and a new check is performed.

[0157] - If so, the vacuum pumping system is operating normally (step 329).

[0158] Figure 7 This shows the management unit 90 in relation to... Figure 6 The flowchart shows the operation under the same conditions, but it is applied to a vacuum pumping system that includes two rotary vane vacuum pumps with significantly different sizes.

[0159] In this scenario, only the smaller pump is started initially, while the larger pump is started at a later stage.

[0160] therefore, Figure 7 Flowcharts and Figure 6 The difference in the flowchart is that it initially includes the following steps:

[0161] -Make the frequency of the first rotary vane vacuum pump 20 reach the first check value (step 331);

[0162] - The management unit checks whether the first pump has reached the first check value after the first predetermined time interval (step 333);

[0163] - If not, shut off the pump (step 335);

[0164] - If so, make the frequency of the second rotary vane vacuum pump 30 reach the first check value (step 337).

[0165] Then, the operation and reference of the management unit. Figure 6 The described operation is the same.

[0166] It will be apparent to those skilled in the art that the above description is given by way of non-limiting example only, and many variations and modifications are possible without departing from the scope of the invention as defined by the appended claims.

[0167] For example, many other operating conditions of the vacuum pumping system and corresponding parameters related to potential contamination risks can obviously be considered.

[0168] Furthermore, although a rotary vane vacuum pump is referenced in the description of the preferred embodiment of the invention, it is clear that the invention can be applied to vacuum pumping systems having multiple positive displacement vacuum pumps.

[0169] For example, the present invention can be applied to a vacuum pumping system having multiple vortex vacuum pumps.

[0170] In this scenario, the risk of contamination is related to dust that may be present at the inlet of the vortex vacuum pump: if one of the vortex vacuum pumps stops due to failure, the other vacuum pump in the vacuum pumping system may suck up the dust from the inlet of the stopped vortex vacuum pump; thus, the sucked-up dust will pass through the vacuum chamber to which the vacuum pump is connected, and the end result is that the vacuum pumping system becomes contaminated.

[0171] Now for reference Figure 8 An example property spectrometer system 800, illustrating a vacuum pumping system implementing various aspects of this teaching, is depicted schematically. Figure 8 As shown, an exemplary mass spectrometer system 800 typically includes an ion source 802 for generating ions within an ionization chamber 850. The ions are then transported in the general direction indicated by the arrows through various differentially pumped vacuum chambers 860, 870, and 880a, 880b housing one or more ion directors (e.g., ion director 806, ion director 810, ion director 814, mass spectrometer 818) for processing, mass analysis, and / or detection. A management unit 890 is operatively connected to a vacuum pumping system including one or more positive displacement vacuum pumps 820, 830 and one or more turbomolecular pumps 840a, 840b. The management unit 890 is configured to maintain the respective chambers at various operating pressures as discussed elsewhere herein.

[0172] Ion source 802 can be any known or subsequently developed ion source for generating ions and modified according to this teaching. Non-limiting examples of ion sources suitable for this teaching include atmospheric pressure chemical ionization (APCI) sources, electrospray ionization (ESI) sources, continuous ion sources, pulsed ion sources, inductively coupled plasma (ICP) ion sources, matrix-assisted laser desorption / ionization (MALDI) ion sources, glow discharge ion sources, electron-bombardment ion sources, chemical ionization sources, or photoionization ion sources, etc. Additionally, as shown in FIG1, system 800 may include a sample source configured to supply a sample to ion source 802. The sample source can be any suitable sample inlet system known in the art. For example, ion source 802 can be configured to receive fluid samples from various sample sources, including reservoirs containing fluid samples to be delivered to the sample source (e.g., pumped), liquid chromatography (LC) columns, capillary electrophoresis devices, and methods for jetting samples into a carrier liquid. Figure 8 In the example shown, the ion source 802 includes an electrospray electrode that may include a capillary (e.g., through one or more conduits, channels, pipes, tubes, capillaries, etc.) coupled to the sample source fluid and terminates at an outlet that extends at least partially into the ionization chamber 850 to discharge a liquid sample therein.

[0173] The analyte of interest contained in the sample discharged from ion source 802 can be ionized within ionization chamber 850, which is separated from first vacuum chamber 860 by a baffle plate 804a and an orifice plate 804b having an orifice (e.g., orifice 861) providing fluid communication between ionization chamber 850 and first vacuum chamber 860. In this embodiment, the orifice in baffle plate 804a and orifice plate 804b is large enough to allow incoming ions to enter first vacuum chamber 860. As an example, the orifice (e.g., orifice 861) can be generally circular in diameter ranging from about 0.6 mm to about 10 mm.

[0174] Although Figure 8 The schematic diagram is not shown, but system 800 may include various other components. For example, system 800 may include a shielding gas supplier (not shown) that provides a shielding gas flow (e.g., N2) adjacent to shielding plate 804 to help reduce contamination in the downstream vacuum chamber of the high vacuum (e.g., by depolymerization and removal of large neutral particles). In some aspects, a portion of the shielding gas may flow out from shielding plate orifice 861 into ionization chamber 850, thereby preventing droplets and / or neutral molecules from entering through shielding plate orifice 861.

[0175] In various respects, the ionization chamber 850 can be maintained at a pressure P0, which can be atmospheric pressure or approximately atmospheric pressure (e.g., about 760 Torr). However, in some embodiments, the ionization chamber 850 can be evacuated to a pressure below atmospheric pressure, for example, via a pump (not shown) coupled to the ionization chamber 850.

[0176] Initially, ions generated by ion source 802 could be produced by... Figure 8 The ion beam is continuously transmitted in the direction indicated by the arrow through upstream ion directors 806, 810, 814 located in the differential pumping intermediate vacuum chambers 860, 870, 880a to generate a narrow and highly focused ion beam (e.g., along the central longitudinal axis of the system 800) for further m / z-based analysis in the high vacuum chamber 880b in which the mass spectrometer 818 is arranged.

[0177] The upstream ion directors 806, 810, and 814 can have various different configurations. As a non-limiting example, the first ion director 806 may include a collection of rods arranged in a twelve-pole configuration to provide a pathway for ions to pass through the ion director 806. An example of such an ion director is described in U.S. Patent No. 10,475,633, the teachings of which are incorporated herein by reference in their entirety. More generally, the first ion director 806 may include any number of rods, for example, multiple rods maintained in a quad, hexa, octa, or twelve-pole configuration, or may be formed using a series of stacked rings such that applying a DC and / or RF voltage to one or more of these rods or rings in a manner known in the art, combined with gas dynamics, can allow the ion director 806 to concentrate ions received through the aperture 861 as the ion director 806 passes through the ion director 806 to be transported to downstream elements.

[0178] As further described herein, the operation of the vacuum pumping system can maintain the pressure in each chamber within a desired range. For example, a first positive displacement vacuum pump 820 can be connected to the first chamber 860 via, for example, an opening or port, to apply negative pressure to the chamber 860 to maintain the pressure (P1) in the first vacuum chamber 860 between about 1 Torr and about 100 Torr, although other pressures may also be used for this or other purposes. In some aspects, chamber 860 can be maintained in the range of about 1 Torr to about 15 Torr, for example, in the range of about 4 Torr to about 8 Torr.

[0179] An aperture 871 located in an ion lens 808 (also referred to herein as IQ00) downstream of the first ion guide 806 allows ions to be transferred from the first vacuum chamber 860 to a second downstream vacuum chamber 870, in which another ion guide 810 is positioned. It should be understood that the vacuum chambers 860 and 870 are thus fluidly connected through the aperture 871, allowing gas to flow between them based on, for example, the pressure difference between them. In this embodiment, the aperture 871 in the ion lens 808 is large enough to allow ions transferred from the first ion guide 806 to enter the second vacuum chamber 870.

[0180] Ion director 810 may have the same or different configuration as ion director 808, but is generally configured to, for example, use a combination of electric field and gas dynamics to converge ions received through orifice 871 to downstream elements. As described above, a power source (not shown) may apply RF and / or DC voltages to the rod of ion director 810 to radially confine and converge ions as they pass through.

[0181] like Figure 8 As shown, the vacuum pumping system may further include at least a second positive displacement vacuum pump 830, which may be coupled to chamber 870 (e.g., via an opening or port) to apply negative pressure to chamber 870 to maintain the pressure (P2) in the second vacuum chamber 870 within a desired range. In some embodiments, the pressure within chamber 870 is typically maintained at a pressure lower than that in chamber (P1). As a non-limiting example, the pressure (P2) in the second vacuum chamber may be maintained in the range of about 500 mTorr to about 5 Torr, but other pressures may be used for this or for other purposes.

[0182] An ion lens 812 (also referred to as IQ0) separates a second vacuum chamber 870 from a third vacuum chamber 880a, in which another ion guide 814 can be disposed. An aperture 881 disposed within the ion lens 812 allows ions transported from the ion guide 810 to pass through into the third vacuum chamber 880a. It should be understood that the vacuum chambers 870 and 880a are thus fluidly connected through the aperture 881, allowing gas to flow between them, for example, based on a pressure difference. In this embodiment, the aperture 881 in the ion lens 812 is large enough to allow ions transported from the second ion guide 810 to enter the third vacuum chamber 880a.

[0183] Ion director 814 may have the same or different configuration as ion director 810, but is generally configured to further converge ions received through aperture 881 as they pass through an intermediate pressure zone before being transported to mass spectrometer 818 via aperture 891 (also referred to herein as "IQ1") in ion lens 816. In some embodiments, ion director 814 (also referred to herein as "Q0") may be an RF ion director and may include a quadrupole assembly. As described above, a power source (not shown) may apply RF to the bars of ion director 814 to radially confine and converge ions as they pass through.

[0184] like Figure 8 As shown, the vacuum pumping system may also include at least a first high vacuum pump 840a for maintaining the vacuum chamber 880a containing the ion guide Q0 at an intermediate pressure (P3) between the vacuum chamber 870 (e.g., at P2) and the vacuum chamber 880b (e.g., at P4).

[0185] Vacuum pump 840a can be any pump known in the art, such as a turbomolecular pump, which is typically capable of maintaining chamber 880a at a pressure at least below about 100 mTorr. In some embodiments, the third vacuum chamber 880a can be maintained at a pressure between about 3 and 15 mTorr, but other pressures can be used for this or other purposes. While positive displacement pumps 820, 830 may not be able to maintain such low pressures alone, a second positive displacement pump 830 can be coupled (e.g., in series) to pump 840a for use as... Figure 8 The forepump shown helps maintain the reduced pressure in the third vacuum chamber 880a.

[0186] Ions are transported from ion guide 814 into a vacuum chamber 880b housing a mass spectrometer 818, which typically operates at very low pressure (high vacuum) to reduce the chance of collisions between the ions and other molecules (e.g., gas molecules) within one or more mass analyzers, in order to characterize the ions based on their mass-to-charge ratio (m / z). As a non-limiting example, in one embodiment, the mass spectrometer 818 may include a detector and two quadrupole mass analyzers (e.g., Q1, Q3) with a collision cell (e.g., q2) located between them. It will be apparent to those skilled in the art that the mass spectrometer 818 employed may take the form of a quadrupole mass spectrometer, a triple quadrupole mass spectrometer, a time-of-flight mass spectrometer, an FT-ICR mass spectrometer, or an orbital trap mass spectrometer, all of which are non-limiting examples.

[0187] like Figure 8 As shown, the vacuum pumping system may further include a second high-vacuum pump 840b for maintaining the vacuum chamber 880b housing the mass spectrometer 818 at a vacuum level of 1 × 10⁻⁶. -4Torr or lower pressure (P4) (e.g., approximately 5 × 10⁻⁶) -5 (P4) can be used for this or other purposes, but other pressures can also be used. As shown, the second positive displacement pump 830 can be coupled (e.g., in series) to pump 840b as a backing pump to help maintain the pressure (P4) within the desired range. That is, in some embodiments, the second positive displacement pump 830 can be used as a backing pump for two turbomolecular pumps 840a, 840b operating in parallel to maintain the two chambers 880a, 840b under a pressure differential.

[0188] It should be understood that not only are adjacent vacuum chambers (e.g., chambers 870, 880a) fluidly coupled through orifices (e.g., orifice 881), but each vacuum chamber in example system 800 is indirectly coupled to one another. In this way, based on the relative pressures between the various chambers, it will be apparent from this teaching that even without direct coupling to a vacuum chamber, the operation (or failure) of a pump (e.g., pump 820) can affect the pressure in that vacuum chamber and the inflow or outflow of gas into or out of the vacuum chamber. As a non-limiting example, if both pumps 420 and 430 are shut down in an uncoordinated manner, an airflow may be generated between the downstream chambers due to the pressure difference between each chamber. However, as further discussed herein (e.g., referring to Figure 3-), Figure 7 The synchronous control of parallel pumps 820 and 830 effectively prevents contamination of system 800 caused by backflow due to uncoordinated operation of one or more of pumps 820 and 830. Such contamination increases the cost of the mass spectrometry system due to higher cleaning costs and instrument downtime. Furthermore, management unit 890 can be configured to perform corrective actions on turbomolecular vacuum pumps 840a and 840b in case of erroneous or asynchronous operation of the positive displacement vacuum pumps 820 and 830. For example, management unit 890 can also be configured to shut down turbomolecular vacuum pumps 840a and 840b if the detection value of one or more identification parameters of one or more of the positive displacement vacuum pumps exceeds the corresponding threshold or if the detection state of one or more identification parameters is inconsistent with the corresponding threshold state.

[0189] Figure 9 This is a block diagram illustrating a computer system 900 on which embodiments of the present teachings can be implemented to prevent backflow from at least one of pumps 820, 830 to Figure 8The recirculation conditions in the vacuum chambers 860 and 870. The computer system 900 includes a bus 922 or other communication mechanism for transmitting information and a processor 920 coupled to the bus 922 to process information. The computer system 900 also includes a memory 924, which may be random access memory (RAM) or other dynamic storage device, coupled to the bus 922 to store instructions to be executed by the processor 920. The memory 924 can also be used to store temporary variables or other intermediate information during the execution of instructions to be executed by the processor 920. The computer system 900 also includes a read-only memory (ROM) 926 or other static storage device coupled to the bus 922 to store static information and instructions for the processor 920. For example, a storage device 928, such as a disk or optical disk, is provided and coupled to the bus 922 for storing information and instructions.

[0190] Computer system 900 can be coupled to display 930, such as a cathode ray tube (CRT) or liquid crystal display (LCD), via bus 922 for displaying information to the computer user. Input device 932, including alphanumeric keys and other keys, is coupled to bus 922 to transmit information and command selections to processor 920. Another type of user input device is cursor controller 934, such as a mouse, trackball, or cursor arrow keys, used to transmit directional information and command selections to processor 920 and control cursor movement on display 930. This input device typically has two degrees of freedom on two axes, namely the first axis (x) and the second axis (y), which allows the device to specify position in a plane.

[0191] Computer system 900 can execute this teaching. Consistent with certain implementations of this teaching, in response to processor 920 executing one or more sequences of one or more instructions contained in memory 924, computer system 900 provides results. Such instructions may be read into memory 924 from another computer-readable medium (e.g., storage device 928). Execution of the sequence of instructions contained in memory 924 causes processor 920 to perform the processes described herein. Alternatively, this teaching may be implemented using hardwired circuitry instead of or in combination with software instructions. Therefore, implementations of this teaching are not limited to any particular combination of hardware circuitry and software. For example, according to various embodiments, this teaching may be executed by a system including one or more different software modules for the operation of a synchronous pump to prevent backflow conditions.

[0192] In various embodiments, computer system 900 can be connected to one or more other computer systems, such as computer system 900, via a network to form a networked system. This network can include a private network or a public network such as the Internet. In a networked system, one or more computer systems can store data and provide data to other computer systems. In a cloud computing scenario, one or more computer systems storing and serving data can be referred to as servers or the cloud. One or more computer systems can include, for example, one or more web servers. Other computer systems that send and receive data to and from the server or cloud can be referred to as, for example, clients or cloud devices.

[0193] As used herein, the term "computer-readable medium" refers to any medium that participates in providing instructions to processor 920 for execution. Such media can take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical discs or magnetic disks, such as storage device 928. Volatile media include dynamic memory, such as memory 924. Transmission media include coaxial cables, copper wires, and optical fibers, including the conductors constituting bus 922.

[0194] Common forms of computer-readable media or computer program products include, for example, floppy disks, collapsible disks, hard disks, magnetic tapes or any other magnetic media, CD-ROMs, digital video discs (DVDs), Blu-ray discs, any other optical media, thumb drives, memory cards, RAM, PROMs and EPROMs, flash memory, any other memory chips or memory cartridges, or any other tangible media from which a computer can read.

[0195] Various forms of computer-readable media may involve carrying one or more sequences of one or more instructions to processor 920 for execution. For example, instructions may initially be carried on a disk of a remote computer. The remote computer may load the instructions into its dynamic memory and transmit them over a telephone line using a modem. A modem local to computer system 900 may receive data over the telephone line and convert the data into an infrared signal using an infrared transmitter. An infrared detector coupled to bus 922 may receive the data carried in the infrared signal and place the data on bus 922. Bus 922 carries the data to memory 924, from which processor 920 fetches and executes the instructions. Instructions received by memory 924 may optionally be stored on storage device 928 before or after execution by processor 920.

[0196] For purposes of illustration and description, various implementations of this teaching have been described herein. These are not exhaustive and do not limit this teaching to the precise form disclosed. Modifications and variations are possible based on the foregoing teachings, or may be derived from practice of this teaching. Furthermore, the described implementations include software, but this teaching can be implemented as a combination of hardware and software or solely as hardware. This teaching can be implemented using both object-oriented and non-object-oriented programming systems.

Claims

1. A vacuum pumping system (100) having a plurality of positive displacement vacuum pumps (20, 30), the plurality of positive displacement vacuum pumps (20, 30) being respectively connected to the same vacuum chamber (60) or to interconnected vacuum chambers (60, 70), the system comprising a management unit (90) for controlling the plurality of positive displacement vacuum pumps (20, 30), the plurality of positive displacement vacuum pumps (20, 30) including at least two positive displacement vacuum pumps respectively connected to the same vacuum chamber (60) or to interconnected vacuum chambers (60, 70), the management unit (90) being configured as follows: - Identify one or more operating parameters of the positive displacement vacuum pump, which are related to the risk of the vacuum pumping system being contaminated by one or more components of the positive displacement vacuum pump; - Set a threshold or threshold state for each of the identified parameters; - For each of the positive displacement vacuum pumps, the identified parameters are detected; - For each of the positive displacement vacuum pumps, the detected value or state of the identified parameter is compared with the corresponding threshold or threshold state. The management unit (90) is characterized in that it is further configured as follows: If the detected value of one or more identified parameters of one of the positive displacement vacuum pumps connected to the same vacuum chamber (60) or connected to interconnected vacuum chambers (60, 70) exceeds the corresponding threshold, or if the detected state of one or more identified parameters of one of the positive displacement vacuum pumps is inconsistent with the corresponding threshold state, then all the positive displacement vacuum pumps connected to the same vacuum chamber (60) or connected to interconnected vacuum chambers (60, 70) shall be shut down synchronously.

2. The vacuum pumping system according to claim 1, wherein, The operating parameters are selected from the group consisting of: pump frequency, power absorbed by the vacuum pump, current absorbed by the vacuum pump, voltage absorbed by the vacuum pump, and temperature of one or more selected components of the vacuum pump.

3. The vacuum pumping system (100) according to claim 1, wherein, The management unit (90) is also configured to: An alarm is triggered if the detected value of one or more identified parameters in one or more of the positive displacement vacuum pumps exceeds the corresponding threshold, or if the detected state of one or more identified parameters in one or more of the positive displacement vacuum pumps is inconsistent with the corresponding threshold state.

4. The vacuum pumping system (100) according to any one of claims 1 to 3, wherein, The management unit (90) is configured to perform at least one of the following actions: - Detect the identified parameters and compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps simultaneously. - Detect the identified parameters and compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps in a predetermined order. - Detect the identified parameters and continuously compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps; - Detect the identified parameters and compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps at predetermined time intervals.

5. The vacuum pumping system (100) according to any one of claims 1 to 3, wherein, The positive displacement vacuum pump is a rotary vane vacuum pump (20, 30).

6. The vacuum pumping system (100) according to claim 5, wherein, The rotary vane vacuum pump (20, 30) includes a housing receiving a pump body, a stator defining a cylindrical pumping chamber within the pump body, a cylindrical rotor housed in the pumping chamber and positioned eccentrically relative to the axis of the pumping chamber, one or more radially movable radial vanes mounted on the rotor and held against the wall of the pumping chamber, a certain amount of oil introduced into the housing for use as a coolant and lubricating fluid, and wherein the management unit (90) is configured as follows: -If the detected value of one or more identified parameters of one of the rotary vane vacuum pumps exceeds the corresponding threshold, or if the detected state of one or more identified parameters of one of the rotary vane vacuum pumps is inconsistent with the corresponding threshold state, then all the rotary vane vacuum pumps (20, 30) shall be shut down synchronously. This prevents oil from the at least one rotary vane vacuum pump from being drawn through the vacuum pumping system by the other rotary vane vacuum pump.

7. A method of operating a vacuum pumping system (100) having a plurality of positive displacement vacuum pumps (20, 30), the plurality of positive displacement vacuum pumps (20, 30) being respectively connected to the same vacuum chamber (60) or to interconnected vacuum chambers (60, 70), the plurality of positive displacement vacuum pumps (20, 30) including at least two positive displacement vacuum pumps respectively connected to the same vacuum chamber (60) or to interconnected vacuum chambers (60, 70), the method comprising the steps of: - Identify one or more operating parameters of the positive displacement vacuum pump, which are related to the risk of the vacuum pumping system being contaminated by one or more components of the positive displacement vacuum pump; - Set a threshold or threshold state for each of the identified parameters; - Parameters identified for each of the detectors in the positive displacement vacuum pump; - For each of the positive displacement vacuum pumps, the detected value or state of the identified parameter is compared with the corresponding threshold or threshold state. If the detected value of one or more identified parameters of one of the positive displacement vacuum pumps connected to the same vacuum chamber (60) or connected to interconnected vacuum chambers (60, 70) exceeds the corresponding threshold, or if the detected state of one or more identified parameters of one of the positive displacement vacuum pumps is inconsistent with the corresponding threshold state, then all the positive displacement vacuum pumps connected to the same vacuum chamber (60) or connected to interconnected vacuum chambers (60, 70) shall be shut down synchronously.

8. The method according to claim 7, wherein, The operating parameters are selected from the group consisting of: pump frequency, power absorbed by the vacuum pump, current absorbed by the vacuum pump, voltage absorbed by the vacuum pump, and temperature of one or more selected components of the vacuum pump.

9. The method according to claim 7, wherein, The method includes the following steps: An alarm is triggered if the detected value of one or more identified parameters in one or more of the positive displacement vacuum pumps exceeds the corresponding threshold, or if the detected state of one or more identified parameters in one or more of the positive displacement vacuum pumps is inconsistent with the corresponding threshold state.

10. The method according to any one of claims 7 to 9, wherein, The method includes at least one of the following steps: - Detect the identified parameters and compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps simultaneously. - Detect the identified parameters and compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps in a predetermined order. - Detect the identified parameters and continuously compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps; - Detect the identified parameters and compare the detected values ​​or states of the identified parameters with the corresponding thresholds or threshold states of the plurality of positive displacement vacuum pumps at predetermined time intervals.

11. The method according to any one of claims 7 to 9, wherein, The positive displacement vacuum pump is a rotary vane vacuum pump (20, 30).

12. The method according to claim 11, wherein, The at least one rotary vane vacuum pump (20, 30) includes a housing receiving a pump body, a stator defining a cylindrical pumping chamber within the pump body, a cylindrical rotor housed within the pumping chamber and eccentrically positioned relative to the axis of the pumping chamber, one or more radially movable radial vanes mounted on the rotor and held against the wall of the pumping chamber, a quantity of oil introduced into the housing for use as a coolant and lubricating fluid, and wherein the method includes the following steps: If the detected value of one or more identified parameters of one of the rotary vane vacuum pumps exceeds the corresponding threshold, or if the detected state of one or more identified parameters of one of the rotary vane vacuum pumps is inconsistent with the corresponding threshold state, then all rotary vane vacuum pumps (20, 30) shall be shut down synchronously. This prevents oil from the at least one rotary vane vacuum pump from being drawn through the vacuum pumping system by the other rotary vane vacuum pump.

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