Vacuum pump and method for injecting a purge gas

Abstract

The vacuum pump (1) includes at least one injection passage (10) exposed through at least one injection hole (15) configured to inject purge gas onto the support surface of the valve seat (5) and / or onto the movable sealing member (6) and / or onto at least one guide element (13) fixed to the stator component (12) of the vacuum pump (1) in the open position of the check valve (4), the guide element (13) being configured to guide the movement of the movable sealing member (6) between the open and closed positions of the check valve (4).

Description

Technical Field

[0001] This invention relates to a dry vacuum pump. It also relates to a method for injecting (or spraying) purge gas into the vacuum pump. Background Technology

[0002] Some vacuum pumps use a so-called "powder" method because they utilize gases that produce a large amount of solid byproducts. This is the case, for example, in certain semiconductor manufacturing processes, some coating deposition processes, flat panel display manufacturing processes, or LED manufacturing processes.

[0003] When pumping gases produced by these methods, solid compounds may form and deposit in the vacuum pump or piping, which can limit gas passage size and lead to a loss of pumping capacity. These deposits can also disrupt the proper operation of the moving parts of the vacuum pump, especially the rotor rotating in the stator and the moving parts of the recirculation, depressurization, or discharge check valves.

[0004] Check valves function as pressure relief valves, opening to prevent unwanted overpressure in the vacuum pump. They also allow gas to circulate in only one direction. Check valves need to be able to open based on a pressure differential, but they must also close tightly. One consequence of excessive deposit buildup in the vacuum pump can be that one of these two functions is no longer properly guaranteed. Such a failure can negatively impact productivity, pose safety risks to personnel, and damage equipment.

[0005] These risks can be mitigated by applying a non-stick coating such as PTFE to the moving parts and seats of the valve, but this material is expensive and its use has a significant environmental impact due to its potentially toxic properties. Coatings can also be deposited by sputtering, but their strength cannot be guaranteed over time. Another solution is to arrange check valves horizontally, allowing gravity to help remove deposited powder. However, generally adherent deposits may be difficult to remove by gravity alone. Summary of the Invention

[0006] One object of the present invention is to provide an enhanced vacuum pump that at least partially addresses one of the shortcomings of the prior art.

[0007] Therefore, the subject of this invention is a vacuum pump, comprising:

[0008] - At least one pump stage, in which two rotors are configured to rotate synchronously in opposite directions to drive the gas to be pumped.

[0009] - At least one check valve, comprising a valve seat and a movable sealing member, the check valve being configurable in a closed position and an open position, wherein in the closed position the movable sealing member closes a passage in the valve seat, and in the open position the movable sealing member releases the passage, the pressure difference across the movable sealing member enabling the check valve to open, characterized in that the vacuum pump further comprises at least one injection passage exposed through at least one injection orifice configured to deliver purge gas:

[0010] - In the open position of the check valve, spray onto the support surface of the valve seat and / or

[0011] - Spray onto the active closure component and / or

[0012] - The spray is applied to at least one guide element fixed to the stator component of the vacuum pump, the guide element being configured to guide the movement of the movable closing member between the open and closed positions of the check valve.

[0013] The injection of purge gas cleans the check valve, preventing the presence of deposits that could hinder its operation. Cleaning the check valve ensures its sealing and opening functions under overpressure conditions for a longer period.

[0014] The vacuum pump may include at least one injection channel exposed through at least one injection orifice configured to inject purge gas onto the support surface of the valve seat when the check valve is in the open position. This purging of the support surface ensures that the surface of the valve seat in contact with the moving sealing member is free of particles or deposits when the valve is in the closed position, guaranteeing a tight closure of the check valve.

[0015] The movable closed component can be translated, rotated, or moved by a combination of motions.

[0016] The check valve may include at least one guide element fixed to a stator component of the vacuum pump, the guide element being configured to guide movement of a movable sealing member between an open position and a closed position of the check valve. The vacuum pump may include at least one injection channel exposed through at least one injection orifice configured to inject purge gas onto the guide element, which ensures the guiding function of the movable sealing member.

[0017] According to an exemplary embodiment, the guiding element includes a rod that engages with a guiding sleeve of the movable closure member to guide axial translational movement of the movable closure member. The injection channel may be configured to inject purge gas along the rod of the guiding element. The rod and / or the guiding sleeve of the movable closure member may therefore have helical grooves communicating with the injection channel for guiding the purge gas.

[0018] According to another exemplary embodiment, the check valve has a rotary guide element for the movable closing member.

[0019] The vacuum pump may include at least one injection channel exposed through at least one injection orifice configured to inject purge gas onto the movable sealing member, particularly in the closed position of the check valve. Injecting purge gas onto the movable sealing member prevents the accumulation of deposits that could prevent or limit the opening of the check valve.

[0020] For example, a vacuum pump may include an injection channel comprising a first channel formed in a guide element, the first channel being exposed through at least one injection hole to inject purge gas onto the movable sealing member when the check valve is in the closed position.

[0021] Vacuum pumps may also include one or more of the features described below, either individually or in combination.

[0022] The injection passage may include at least one injection orifice for purge gas, which is blocked by a movable sealing member in the closed position of the check valve and released in the open position. The check valve is thus self-closing; closing the check valve stops the injection of purge gas.

[0023] The check valve may include a resilient reset member that applies a force to the movable closing member to bring it into a closed position (closed position).

[0024] The vacuum pump may include an injection channel comprising a first channel formed in a guide element and at least one second channel formed in a movable closure member, the second channel being exposed through at least one injection orifice arranged facing the valve seat, the first and second channels communicating with each other. Purge gas thereby cleans the support surface of the valve seat through the guide element.

[0025] When the guiding element includes a rod that cooperates with the guiding sleeve of the movable closure member to guide the axial translational movement of the movable closure member, at least one injection hole of the first channel of the guiding element and the guiding sleeve of the movable closure member can be positioned relative to each other as follows:

[0026] -Purge gas can be injected through at least one injection orifice of the guide element when the check valve is in the closed position, and

[0027] - Purge gas can be injected through at least one injection hole exposed from the movable sealing member when the check valve is in the open position.

[0028] The injection of purging gas therefore varies depending on the position of the check valve, thus cleaning the support surface of the valve seat when the check valve is open, or cleaning the rear portion of the moving sealing member when the check valve is closed.

[0029] According to another exemplary embodiment, the injection channel exposed through at least one injection hole is configured to inject purge gas along a direction tangent to a plane that separates the planar support surface of the valve seat and the complementary planar surface of the movable closing member when the check valve is in the open position.

[0030] According to another exemplary embodiment, the injection channel exposed through at least one injection hole is configured to inject purge gas onto the conical flank of the head of the movable sealing member that blocks the channel when the check valve is in the closed position.

[0031] At least one injection channel can be configured to inject a vortex-shaped purge gas. The vortex of the purge gas can improve cleaning.

[0032] A vacuum pump may include at least two pump stages, and a check valve is a pressure relief valve located at the output of the first or second pump stage. In the open position, this pressure relief valve allows the last few pump stages of the vacuum pump to be short-circuited (bypassed), which may limit the total generated flow rate when pumping a strong gas flow.

[0033] A vacuum pump may include at least two pump stages, and a check valve is a discharge valve located at the output of the last pump stage. This discharge check valve prevents pumped gas from returning to the vacuum pump.

[0034] The check valve can be a recirculation check valve connected between the output and input of the first pump stage. When pumping a strong gas flow, opening the check valve allows the gas to be pumped to recirculate within the same pump stage.

[0035] Another subject of the invention is a method for injecting purge gas into a vacuum pump as described above, characterized in that, in the open position of the check valve, the purge gas is injected onto the support surface of the valve seat, and / or onto the movable sealing member, and / or onto a guide element fixed to the stator component of the vacuum pump, the guide element being configured to guide the movement of the movable sealing member between the open and closed positions of the check valve. Attached Figure Description

[0036] Other features and advantages of the invention will become apparent from the following description, given with reference to the accompanying drawings and as non-limiting examples, in which:

[0037] Figure 1 This diagram shows a pump unit that includes a multi-stage primary vacuum pump and a Roots vacuum pump installed upstream of the primary vacuum pump.

[0038] Figure 2 A schematic cross-sectional view of a check valve according to a first exemplary embodiment is shown, in the closed position.

[0039] Figure 3 It shows Figure 2The check valve in the middle is in the open position.

[0040] Figure 4 It shows Figure 2 The moving sealing component of the check valve, which is related to... Figure 2 The view has been flipped compared to the previous one.

[0041] Figure 5 A schematic cross-sectional view of a check valve according to a second exemplary embodiment is shown, in the closed position.

[0042] Figure 6 It shows the relationship with Figure 5 A similar view, which is in the open position.

[0043] Figure 7 A schematic cross-sectional view of a check valve according to a third exemplary embodiment is shown, in the open position.

[0044] Figure 8 Shown from above Figure 7 A variant of the check valve.

[0045] Figure 9 A schematic cross-sectional view of a check valve according to a fourth exemplary embodiment is shown, in the closed position.

[0046] Figure 10 A schematic cross-sectional view of a check valve according to a fifth exemplary embodiment is shown, in the closed position.

[0047] Figure 11 A schematic cross-sectional view of a check valve according to a sixth exemplary embodiment is shown, in the closed position.

[0048] In these figures, the same elements have the same reference numerals. Detailed Implementation

[0049] The following embodiments are examples. Although the description relates to one or more embodiments, this does not necessarily mean that every reference relates to the same embodiment, or that these features apply only to a single embodiment. Simple features of different embodiments may also be combined or interchanged to provide other embodiments.

[0050] A primary vacuum pump is defined as a positive displacement vacuum pump, constructed using two rotors to draw in, transfer, and then discharge the gas to be pumped at atmospheric pressure. The rotors are supported by two shafts, which are driven to rotate by the motor of the primary vacuum pump. A primary vacuum pump can be multistage, meaning it comprises multiple stages (at least two), for example, two to nine pump stages.

[0051] A Roots vacuum pump (also known as a "Roots blower") is defined as a positive displacement vacuum pump, constructed to use a Roots rotor to draw in, transfer, and then discharge the gas to be pumped. The Roots vacuum pump is installed upstream of and in series with a primary vacuum pump. The rotor is supported by two shafts, which are driven to rotate by the Roots vacuum pump's motor. A Roots vacuum pump consists of one to three pump stages.

[0052] "Upstream" should be understood as an element located before another element relative to the gas circulation direction. On the other hand, "downstream" should be understood as an element located after another element relative to the circulation direction of the gas to be pumped.

[0053] Vacuum pump 1 is connected, for example, to a chamber for pumping gas. It may be a chamber in which deposition and etching processes or coating processes, flat panel display manufacturing processes, or LED manufacturing processes are carried out for fabricating microelectronic devices on silicon wafers.

[0054] This invention applies to any type of single-stage or multi-stage dry vacuum pump, i.e., it includes one or more stages (at least two). The vacuum pump can be a multi-stage primary vacuum pump configured to discharge the gas to be pumped at atmospheric pressure, or a Roots vacuum pump with one to three pump stages connected upstream of the primary vacuum pump in use.

[0055] As is known per se, vacuum pump 1 includes a mechanical drive section (not shown here), which includes a motor driving a rotor, a rotor synchronizing gear, and bearings supporting the rotor shaft. Vacuum pump 1 also includes a dry pump stage in which gas circulates, and vacuum pump 1 further includes a sealing device that allows the shaft to rotate in the dry pumping section while restricting lubricant transfer from the mechanical drive section to the dry pumping section.

[0056] In the dry pumping section, the vacuum pump 1 includes at least one pump stage 1a-1e, in which two rotors are configured to rotate synchronously in opposite directions to drive the gas to be pumped. The vacuum pump 1 is called "dry" because during operation, the rotors rotate within the stator without any mechanical contact with the stator, which allows oil to be eliminated in the dry pumping section.

[0057] Vacuum pump 1 is, for example, a "Roots" or "claw" type, or a spiral or screw type, or a primary vacuum pump based on another similar positive displacement vacuum pump principle.

[0058] therefore, Figure 1 An example of a pump unit is shown, which includes a single-stage vacuum pump arranged upstream of a multi-stage vacuum pump.

[0059] A multistage vacuum pump 1 includes, for example, five pump stages 1a-1e, which are connected in series between an inlet 2 and an outlet 3. Pump stage 1a, connected to the inlet 2 of the vacuum pump 1, is the first pump stage, also known as the low-pressure stage, and pump stage 1e, connected to the outlet 3, is the last pump stage, also known as the high-pressure stage. The compression chambers of the successive pump stages 1a-1e are connected in series one after another via at least one corresponding interstage channel connecting the output of the compression chamber of the previous stage to the input of the compression chamber of the next stage. During rotation, the gas drawn in from the inlet 2 of the vacuum pump 1 is confined in the volume created by the rotor and the stator of the pump stages 1a-1e, then compressed and driven to the next stage, and so on, until it is driven to the outlet 3 of the vacuum pump 1. The generated volume (i.e., the pumped gas volume) of the pump stages 1a-1e decreases (or remains equal) with each stage, with the first pump stage 1a having the highest generated flow rate and the last pump stage having the lowest generated flow rate.

[0060] The vacuum pump 1 also includes at least one check valve 4. The check valve 4 includes a valve seat 5 and a movable sealing member 6. The movable sealing member 6 can translate, rotate, or move in a combination of movements.

[0061] Check valve 4 can be in the closed position. Figure 2 ) and opening position ( Figure 3 In the closed position, the movable sealing member 6 contacts the support surface of the valve seat 5 and closes the passage 7 in the valve seat 5 for the gas to be pumped. In the open position, the movable sealing member 6 leaves the valve seat 5, allowing the gas to be released.

[0062] Check valve 4 can open based on the pressure difference across the movable sealing member 6. For example, check valve 4 opens in the event of overpressure in the pump stage. When the upstream / downstream pressure difference is below the load threshold of check valve 4, check valve 4 closes, and the movable sealing member 6 prevents gas from passing through. When the upstream / downstream pressure difference of check valve 4 is above the load threshold of check valve 4, the movable sealing member 6 separates from the valve seat 5, releasing the gas to be pumped through the check valve 4.

[0063] Vacuum pump 1 includes, for example, a recirculation check valve 4a and / or at least two pump stages 1a-1e with at least one pressure relief check valve 4b and / or at least one discharge check valve 4c.

[0064] A recirculation check valve 4a (also known as a pressure relief check valve) is connected between the output and input of the same pump stage 1a. It is configured to open as soon as possible when the pressure difference between the input and output of pump stage 1a exceeds a predetermined threshold. In the case of pumping a strong gas flow, the opening of the check valve 4a allows the gas to be pumped to be recirculated within the same pump stage 1a. The threshold is predefined, in particular, based on the resulting flow ratio and according to mechanical safety settings. The recirculation check valve 4a is also arranged between the output and input of, for example, a Roots vacuum pump having one to three stages, positioned upstream of the primary vacuum pump.

[0065] For example, during chamber depressurization at atmospheric pressure, the pressure relief check valve 4b allows for the absorption and timely transfer of a strong gas flow while limiting the power consumption of the vacuum pump 1. It is positioned, for example, at the output of a low-pressure pump stage, such as the output of the first or second pump stage 1a, 1b of a multi-stage vacuum pump 1. In the open position, the pressure relief check valve 4b allows for the short-circuiting of the last few pump stages 1c-1e of the vacuum pump 1, which may limit the total generated flow rate.

[0066] The discharge check valve 4c (also known as a one-way check valve) is located at the output of the last pump stage 1e, that is, at the discharge port 3 of the multistage vacuum pump 1, which is usually located upstream of the silencer of the vacuum pump 1. It prevents the pumped gas in the vacuum pump 1 from flowing back.

[0067] In all arrangements of the check valve 4, the head 8 of the movable sealing member 6 is configured to block the passage 7 for gas.

[0068] exist Figures 2 to 4 In the example, the valve seat 5 has a planar form, and the head 8 has a cylindrical form that complements the channel 7 of the valve seat 5. The movable sealing member 6 and / or the valve seat 5 may also have a sealing coating or gasket 9, which is made of, for example, an elastomeric material or silicone resin, to enhance mechanical strength and high-temperature resistance.

[0069] The check valve 4 may include a resilient reset member 11 that pushes the movable sealing member 6 to the closed position. The resilient reset member 11 may include, for example, a spring inserted between the movable sealing member 6 and the stator component 12 of the vacuum pump 1. Alternatively, gravity may be used instead of a spring to push the movable sealing member 6 to the closed position.

[0070] The check valve 4 may include at least one guide element 13 fixed to the stator component 12, the guide element 13 being configured to guide the movement of the movable closing member 6 between the open and closed positions of the check valve 4.

[0071] According to an exemplary embodiment, the guide element 13 includes a rod that engages with a guide sleeve 14 of the movable closure member 6 to guide axial translational movement of the movable closure member 6. The guide sleeve 14 is, for example, a cylindrical cavity. It may be configured along the central axis of the movable closure member 6. A resilient reset member 11 is, for example, arranged around the rod of the guide element 13, and the rod also guides compression of the resilient reset member 11.

[0072] The vacuum pump 1 also includes at least one injection channel 10 exposed through at least one injection hole 15 configured to inject purge gas onto the support surface of the valve seat 5 and / or onto the movable sealing member 6 and / or the guide element 13 when the check valve 4 is in the open position.

[0073] The purging gas is, for example, nitrogen.

[0074] The jetting of purge gas cleans the check valve 4, preventing the presence of deposits that could hinder its operation. Therefore, the check valve 4 can maintain its sealing and opening functions under overpressure conditions for a longer period between maintenance cycles.

[0075] The purging gas is injected locally onto the moving parts of the check valve 4, such as the support surface of the valve seat 5, the movable sealing member 6, and / or the guide element 13.

[0076] The purging gas injection can be continuous or timely and directional. The discontinuous injection in time allows for pumping by vacuum pump 1 and the final vacuum performance level (in the absence of a pumpable gas flow).

[0077] Specifically, the injection of purge gas can be controlled during a so-called "cleaning" phase, in which no process occurs in the chamber connected to vacuum pump 1. For this purpose, vacuum pump 1 includes, for example, a driver unit configured to receive information about the process occurring in the chamber and to control the injection of purge gas based on that information.

[0078] Discontinuous jetting can also be determined by predefined jetting times.

[0079] According to another example, this discontinuous injection is triggered by the movement of the check valve 4 itself. The injection channel 10 includes at least one injection orifice 15 for purge gas, which is blocked by the movable sealing member 6 in the closed position and released in the open position. The check valve 4 is thus self-closing, and closing the check valve 4 stops the injection of purge gas.

[0080] This embodiment is particularly applicable to cases where the injection channel 10 is exposed through the injection hole 15, which is configured to inject purge gas onto the support surface of the valve seat 5 of the check valve 4 when the check valve 4 is in the open position.

[0081] The purging gas cleans the support surface, ensuring that when the check valve 4 is in the closed position, the surface in contact with the valve seat 5 and the movable sealing member 6 is free of particles or deposits, thus guaranteeing that the check valve 4 is tightly closed.

[0082] For this purpose, for example, the vacuum pump 1 includes an injection channel 10, which includes a first channel 16 formed in the guide element 13 and at least one second channel 17 formed in the movable closure member 6. The at least one second channel 17 is exposed from the movable closure member 6 through a corresponding injection hole 15 arranged to face the valve seat 5. The first channel 16 and the second channel 17 communicate with each other. For example, a plurality of second channels 17 are exposed through corresponding injection holes 15, such as six or ten, which are evenly distributed around the periphery of the movable closure member 6, thereby forming a "nozzle" to evenly clean the support surface of the valve seat 5. Figure 4 ).

[0083] During operation, when the check valve 4 is in the closed position, the injection port 15 of the purging gas is blocked by the movable sealing member 6.

[0084] Under overpressure conditions, the movable sealing member 6 is pushed back against the elastic reset member 11, thereby opening the check valve 4. The opening of the check valve 4 allows the gas to be pumped to pass through and releases the injection orifice 15 to inject purge gas onto the support surface of the valve seat 5. Figure 3 The jet of purge gas cleans the support surface of valve seat 5 through guide element 13.

[0085] Figure 5 and Figure 6 A second exemplary embodiment is shown.

[0086] In this example, the vacuum pump 1 includes an injection channel 10 exposed through at least one injection port 18 configured to inject purge gas onto the rear portion 19 of the movable sealing member 6. More specifically, the injection channel 10 includes a first channel 16 formed in the guide element 13. The first channel 16 is exposed through at least one injection port 18 to inject purge gas onto the movable sealing member 6 when the check valve 4 is in the closed position. Figure 5 ).

[0087] For example, it has at least two radially opposing injection holes 18 exposed from the first channel 16.

[0088] The injection of purge gas onto the rear portion 19 of the movable sealing member 6 allows the movable sealing member 6 to be cleaned in the closed position to avoid the accumulation of deposits that could prevent or limit the opening of the check valve 4.

[0089] In the case where the guide element 13 includes a rod that cooperates with the guide sleeve 14 of the movable closure member 6 to guide the axial translational movement of the movable closure member 6, it is also conceivable that at least one injection hole 18 of the first channel 26 of the guide element 13 and the guide sleeve 14 of the movable closure member 6 are positioned relative to each other to inject purge gas through at least one injection hole 18 of the guide element 13 in the closed position of the check valve 4, and to inject purge gas through at least one injection hole 15 exposed from the movable closure member 6 in the open position of the check valve 4.

[0090] During operation, when check valve 4 is in the closed position ( Figure 5 The rear portion 19 of the movable sealing member 6 is cleaned by spraying purge gas through at least one first spray hole 18 formed in the guide element 13, and powder clumps are prevented from forming on the movable sealing member 6. Furthermore, the second spray hole 15 is blocked by the movable sealing member 6, which contacts the valve seat 5.

[0091] Under overpressure conditions, the movable sealing member 6 is pushed back against the elastic reset member 11, thereby opening the check valve 4. Figure 6 The opening of check valve 4 allows the gas to be pumped to pass through, releases the second injection port 15 to inject purge gas onto valve seat 5, and closes the first injection port 18.

[0092] The injection of purging gas therefore varies depending on the position of the check valve 4, thus cleaning the support surface of the valve seat 5 when the check valve 4 is open, or cleaning the rear portion 9 of the movable sealing member 6 when the check valve 4 is closed.

[0093] Figure 7 A third exemplary embodiment is shown, wherein the injection channel 10 is located in the (fixed) stator component 12 of the vacuum pump 1.

[0094] The vacuum pump 1 includes an injection channel 10 exposed through at least one injection hole 15, which is configured to inject purge gas onto the valve seat 5 of the check valve 4 in a direction tangential to a plane separating the planar support surface of the valve seat 5 and the complementary planar surface of the movable closing member 6 when the check valve 4 is in the open position. Injecting purge gas tangentially cleans the support surface of the valve seat 5, ensuring a tight closure of the check valve 4.

[0095] The vacuum pump 1 may also include an injection channel 10 exposed through at least one injection hole 15 configured to deliver purge gas along the rod of the guide element 13, which ensures the guiding function of the movable sealing member 6 and the resilient reset member 11 when necessary.

[0096] The vacuum pump 1 may also include an injection channel 10 exposed through at least one injection port 15, which is configured to inject purge gas onto the movable sealing member 6, particularly in the closed position, to prevent powder from accumulating on the check valve 4. The purge gas may be injected in a direction perpendicular to or tangential to the surface of the rear portion 19 of the movable sealing member 6.

[0097] The purging gas can be injected continuously or directed in a timely manner. For example, the injection of purging gas can be controlled during the so-called "cleaning" phase or determined by a predetermined injection time.

[0098] The at least one injection channel 10 can be configured to inject a vortex-shaped purge gas. Figure 8 ).

[0099] A vortex effect of gas can be achieved through a combination of a specific orientation of one or more injection holes 15 and at least a partial circular or cylindrical geometry of the stator component 12. This vortex-driven purging of the gas improves cleaning efficiency.

[0100] When the check valve 4 is in the open position, swirling gas can be injected onto the valve seat 5 of the check valve 4 along a direction tangent to the plane that separates the planar support surface of the valve seat 5 and the complementary planar surface of the movable sealing member 6. Swirling gas can also be injected around the guide element 13 or onto the movable sealing member 6.

[0101] Figure 9 A fourth exemplary embodiment is shown.

[0102] In this example, the guide element 13 includes a rod that engages with the guide sleeve 14 of the movable closure member 6 to guide axial translational movement of the movable closure member 6. The vacuum pump 1 includes an injection channel 10 exposed through at least one injection orifice 15 configured to inject purge gas along the rod of the guide element 13. The rod and / or the guide sleeve 14 of the movable closure member 6 thus have, for example, a helical groove 20 communicating with the injection channel 10 for guiding the purge gas. This embodiment allows for the avoidance of deposits on the guide surface of the check valve 4 that could impede its movement. The injection of purge gas ensures easy sliding of the rod within the guide sleeve 14. The purge gas can be injected in both the open and / or closed positions of the check valve 4.

[0103] although Figures 2 to 9A generally cylindrical two-stage movable closure member 6 and a planar valve seat 5 are shown, but other embodiments are possible. Specifically, the movable closure member 6 may be spherical or partially spherical, or have a conical or partially conical head, and the valve seat 5 may be conical. The movable closure member may also have a generally planar form, such as a plate, and move between the open and closed positions of the check valve by pivoting via a rotational guide element of the movable closure member.

[0104] Figure 10 and Figure 11 Another example of the movable closure member 6 is shown, whose head 8 has a tapered wing 21 that complements the tapered valve seat 5 to block the passage 7 of the valve seat 5 in the closed position.

[0105] In this example, the injection channel 10 is exposed through at least one injection hole 15, which is configured to inject purge gas onto the tapered side wing 21 of the head 8 of the movable sealing member 6, thereby blocking the channel 7 in the closed position of the check valve 4. The injection channel 10 is, for example, formed in the stator component 12 of the vacuum pump 1. The vacuum pump 1 includes, for example, a single injection channel 10 exposed through a single injection hole 15, which is configured to inject a larger flow rate (…). Figure 10 Alternatively, the vacuum pump 1 may include a plurality of smaller injection channels 10 configured to inject purge gas onto opposite sides of the head 8 of the movable sealing member 6. Figure 11 ).

[0106] The injection channel 10 can be configured to be perpendicular to the axial movement direction of the check valve. Figure 10 Or, purge gas can be injected along a direction perpendicular to the conical flank 21 of the head 8 of the movable enclosure member 6. Figure 11 ).

Claims

1. A vacuum pump (1), comprising: - At least one pump stage (1a-1e), with two rotors configured to rotate synchronously in opposite directions within the at least one pump stage to drive the gas to be pumped. - At least one check valve (4) comprising a valve seat (5) and a movable closing member (6), the check valve (4) being capable of being in a closed position and an open position. In the closed position, the movable closing member (6) closes the passage (7) of the valve seat (5), and in the open position, the movable closing member (6) releases the passage (7). The pressure difference across the movable closing member (6) is capable of opening the check valve (4). The vacuum pump (1) is characterized in that it further includes at least one injection channel (10) exposed through at least one injection orifice, the injection orifice being configured to deliver purge gas: -In the open position of the check valve (4), spray onto the support surface of the valve seat (5) and / or - Sprayed onto the movable closure member (6) and / or - The spray is applied to at least one guide element (13) fixed to the stator component (12) of the vacuum pump (1), the guide element being configured to guide the movement of the movable closing member (6) between the open and closed positions of the check valve (4). The guide element (13) includes a rod that engages with the guide sleeve (14) of the movable closing member (6) to guide the translational movement of the movable closing member (6). The injection orifice is configured to inject purge gas along the rod, and the guide sleeve (14) of the rod and / or the movable closure member (6) has a spiral groove (20) communicating with the injection channel (10) for guiding the purge gas.

2. A vacuum pump (1), comprising: - At least one pump stage (1a-1e), with two rotors configured to rotate synchronously in opposite directions within the at least one pump stage to drive the gas to be pumped. - At least one check valve (4) comprising a valve seat (5) and a movable closing member (6), the check valve (4) being capable of being in a closed position and an open position. In the closed position, the movable closing member (6) closes the passage (7) of the valve seat (5), and in the open position, the movable closing member (6) releases the passage (7). The pressure difference across the movable closing member (6) is capable of opening the check valve (4). The vacuum pump (1) is characterized in that it further includes at least one injection channel (10) exposed through at least one injection orifice, the injection orifice being configured to deliver purge gas: -In the open position of the check valve (4), spray onto the support surface of the valve seat (5) and / or - Sprayed onto the movable closure member (6) and / or - The spray is applied to at least one guide element (13) fixed to the stator component (12) of the vacuum pump (1), the guide element being configured to guide the movement of the movable closing member (6) between the open and closed positions of the check valve (4). The injection hole is blocked by the movable sealing member (6) in the closed position and released in the open position.

3. A vacuum pump (1), comprising: - At least one pump stage (1a-1e), with two rotors configured to rotate synchronously in opposite directions within the at least one pump stage to drive the gas to be pumped. - At least one check valve (4) comprising a valve seat (5) and a movable closing member (6), the check valve (4) being capable of being in a closed position and an open position. In the closed position, the movable closing member (6) closes the passage (7) of the valve seat (5), and in the open position, the movable closing member (6) releases the passage (7). The pressure difference across the movable closing member (6) is capable of opening the check valve (4). The vacuum pump (1) is characterized in that it further includes at least one injection channel (10) exposed through at least one injection orifice, the injection orifice being configured to deliver purge gas: -In the open position of the check valve (4), spray onto the support surface of the valve seat (5) and / or - Sprayed onto the movable closure member (6) and / or - The spray is applied to at least one guide element (13) fixed to the stator component (12) of the vacuum pump (1), the guide element being configured to guide the movement of the movable closing member (6) between the open and closed positions of the check valve (4). The injection channel (10) includes a first channel (16) formed in the guide element (13), the first channel (16) being exposed by at least one injection hole for injecting purge gas onto the movable sealing member (6) when the check valve (4) is in the closed position.

4. A vacuum pump (1), comprising: - At least one pump stage (1a-1e), with two rotors configured to rotate synchronously in opposite directions within the at least one pump stage to drive the gas to be pumped. - At least one check valve (4) comprising a valve seat (5) and a movable closing member (6), the check valve (4) being capable of being in a closed position and an open position. In the closed position, the movable closing member (6) closes the passage (7) of the valve seat (5), and in the open position, the movable closing member (6) releases the passage (7). The pressure difference across the movable closing member (6) is capable of opening the check valve (4). The vacuum pump (1) is characterized in that it further includes at least one injection channel (10) exposed through at least one injection orifice, the injection orifice being configured to deliver purge gas: -In the open position of the check valve (4), spray onto the support surface of the valve seat (5) and / or - Sprayed onto the movable closure member (6) and / or - The spray is applied to at least one guide element (13) fixed to the stator component (12) of the vacuum pump (1), the guide element being configured to guide the movement of the movable closing member (6) between the open and closed positions of the check valve (4); The injection channel (10) includes a first channel (16) formed in the guide element (13) and at least one second channel (17) formed in the movable closure member (6) and exposed through the at least one injection hole, the at least one injection hole being arranged to face the valve seat (5), the first channel (16) and the second channel (17) communicating with each other.

5. The vacuum pump (1) according to any one of claims 2 to 4, characterized in that, The guiding element (13) includes a rod that engages with the guiding sleeve (14) of the movable closure member (6) to guide the translational movement of the movable closure member (6).

6. The vacuum pump (1) according to claim 3 or 4, characterized in that, The guide element (13) includes a rod that engages with the guide sleeve (14) of the movable closure member (6) to guide translational movement of the movable closure member (6); the at least one injection hole of the first channel (16) of the rod of the guide element (13) and the guide sleeve (14) of the movable closure member (6) are positioned relative to each other as follows: - Purge gas can be injected through at least one injection hole of the rod when the check valve (4) is in the closed position, and -Purge gas can be injected through at least one injection hole exposed from the movable sealing member (6) when the check valve (4) is in the open position.

7. A vacuum pump (1), comprising: - At least one pump stage (1a-1e), with two rotors configured to rotate synchronously in opposite directions within the at least one pump stage to drive the gas to be pumped. - At least one check valve (4) comprising a valve seat (5) and a movable closing member (6), the check valve (4) being capable of being in a closed position and an open position. In the closed position, the movable closing member (6) closes the passage (7) of the valve seat (5), and in the open position, the movable closing member (6) releases the passage (7). The pressure difference across the movable closing member (6) is capable of opening the check valve (4). The vacuum pump (1) is characterized in that it further includes at least one injection channel (10) exposed through at least one injection orifice, the injection orifice being configured to deliver purge gas: -In the open position of the check valve (4), spray onto the support surface of the valve seat (5) and / or - Sprayed onto the movable closure member (6) and / or - The spray is applied to at least one guide element (13) fixed to the stator component (12) of the vacuum pump (1), the guide element being configured to guide the movement of the movable closing member (6) between the open and closed positions of the check valve (4). The injection orifice is configured to inject purge gas along a direction tangent to a plane that separates the planar support surface of the valve seat (5) and the complementary planar surface of the movable closing member (6) when the check valve (4) is in the open position.

8. A vacuum pump (1), comprising: - At least one pump stage (1a-1e), with two rotors configured to rotate synchronously in opposite directions within the at least one pump stage to drive the gas to be pumped. - At least one check valve (4) comprising a valve seat (5) and a movable closing member (6), the check valve (4) being capable of being in a closed position and an open position. In the closed position, the movable closing member (6) closes the passage (7) of the valve seat (5), and in the open position, the movable closing member (6) releases the passage (7). The pressure difference across the movable closing member (6) is capable of opening the check valve (4). The vacuum pump (1) is characterized in that it further includes at least one injection channel (10) exposed through at least one injection orifice, the injection orifice being configured to deliver purge gas: -In the open position of the check valve (4), spray onto the support surface of the valve seat (5) and / or - Sprayed onto the movable closure member (6) and / or - The spray is applied to at least one guide element (13) fixed to the stator component (12) of the vacuum pump (1), the guide element being configured to guide the movement of the movable closing member (6) between the open and closed positions of the check valve (4). The injection channel (10) is configured to inject purge gas into the conical side wing (21) of the head (8) of the movable sealing member (6) that blocks the channel (7) when the check valve (4) is in the closed position.

9. The vacuum pump (1) according to any one of claims 1 to 4 and 7 to 8, characterized in that, The at least one injection channel (10) is configured to inject a vortex-shaped purge gas.

10. The vacuum pump (1) according to any one of claims 1 to 4 and 7 to 8, characterized in that, The check valve (4) includes a resilient reset member (11) that applies a force to bring the movable closing member (6) into the closed position.

11. The vacuum pump (1) according to any one of claims 1 to 4 and 7 to 8, characterized in that, It includes at least two pump stages (1a-1e), and the check valve (4) is a pressure relief check valve (4b) arranged at the output of the first or second pump stage (1a, 1b).

12. The vacuum pump (1) according to any one of claims 1 to 4 and 7 to 8, characterized in that, It includes at least two pump stages (1a-1e), and the check valve (4) is a discharge check valve (4c) arranged at the output of the last pump stage (1e).

13. The vacuum pump (1) according to any one of claims 1 to 4 and 7 to 8, characterized in that, The check valve (4) is a recirculation check valve (4a) connected between the output and input of the first pump stage (1a).

14. A method for injecting purge gas into a vacuum pump (1) according to any one of the preceding claims, characterized in that, In the open position of the check valve (4), purge gas is injected onto the support surface of the valve seat (5), and / or onto the movable sealing member (6), and / or onto the guide element (13) fixed to the stator component (12) of the vacuum pump (1), the guide element (13) being configured to guide the movement of the movable sealing member (6) between the open and closed positions of the check valve (4).

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