Scroll pumps and scroll pump intake valves

Abstract

An intake valve for a scroll pump and a scroll pump are disclosed. The intake valve for the scroll pump includes a valve seat formed by at least one of a stator and an intake cover of the scroll pump, and a sealing mechanism attached to the stator or the intake cover. The sealing mechanism includes an actuator configured to move the sealing mechanism between an open position in which the scroll mechanism and an intake port of the scroll pump are in fluid communication and a closed position in which the sealing mechanism engages the valve seat to seal the scroll mechanism from the intake port.

Description

[Technical Field]

[0001] The field of the invention relates to scroll pumps, and more particularly to intake valves for scroll pumps. [Background technology]

[0002] Scroll pumps may include a backflow prevention exhaust valve to prevent backflow of fluid into the pump from the exhaust, which may be at atmospheric pressure when the scroll pump is shut down. Such backflow is particularly problematic when the scroll pump is used as a vacuum pump. For example, when the scroll pump is used to evacuate a semiconductor process chamber and / or when the scroll pump is used to back a turbomolecular pump (TMP), such backflow can cause rapid pressure changes within the TMP, potentially damaging the pump and / or contaminating the chamber.

[0003] This can be addressed by providing an intake valve rather than an exhaust valve. This configuration prevents fluid within the scroll pump itself from leaking into a low-pressure environment, such as a TMP or semiconductor process chamber. Such an intake valve may be provided as an accessory mounted upstream of the pump, which takes up valuable space and can be expensive. Summary of the Invention [Problem to be solved by the invention]

[0004] It would therefore be desirable to provide a device that addresses one or more of the drawbacks associated with conventional valves. [Means for solving the problem]

[0005] According to one aspect, an intake valve for a scroll pump is provided, the intake valve including a valve seat formed by at least one of a stator and an intake cover of the scroll pump, and a sealing mechanism attached to the stator or the intake cover, the sealing mechanism including an actuator configured to move the sealing mechanism between an open position in which the scroll mechanism is in fluid communication with an intake port of the scroll pump and a closed position in which the sealing mechanism engages the valve seat to seal the scroll mechanism from the intake port.

[0006] In this manner, an intake valve is provided that is formed at least in part into the pump itself. This is a compact configuration that eliminates the need for an external intake valve, thereby reducing the number of connections and additional components required, thereby saving space and cost and reducing system complexity. This is particularly important when using a scroll pump as part of a pumping system to evacuate semiconductor process chambers where space is at a premium. Furthermore, reducing the number of connections reduces the number of potential leak sites, thereby reducing the likelihood of leaks.

[0007] In comparison to an exhaust valve, providing a valve at the inlet prevents backflow from the scroll pump into the pumped environment, such as the process chamber, and helps maintain the environment at a low pressure and free of contaminants such as tip seal dust from the scroll pump, especially when the pump is stopped.

[0008] In some embodiments, the sealing mechanism can be configured to cooperate with the stator and / or the intake cover to define a portion of an intake passage of the scroll pump when the sealing mechanism is in an open position, the intake passage defining a flow path between the intake port and the scroll mechanism.

[0009] Using a sealing mechanism to define the intake passage provides an efficient method of integrating a valve into a scroll pump with reduced additional components.

[0010] In some embodiments, the seat may be formed by the perimeter of a portion of the intake passage. By using the perimeter of a portion of the intake passage to create the valve seat, the sealing mechanism can effectively seal across the entire intake passage defined by that perimeter.

[0011] In some embodiments, the actuator comprises a solenoid coil.

[0012] The intake valve may be a simple on-off valve, with a solenoid coil providing the force to move a sealing mechanism between open and closed positions.

[0013] In some embodiments, the intake valve includes a valve body and a valve seat, the valve body and the valve seat being formed by at least one of the intake cover and the stator. Forming the valve body within the stator and / or intake cover reduces the need for additional components required with an external intake valve within the intake passage, allowing for a more compact configuration. In this way, the number of additional components required to achieve an integrated valve at the intake port is reduced, providing a more compact pump.

[0014] In some embodiments, the valve body and valve seat are formed by machining the metal that forms the stator and / or intake cover.

[0015] According to a further aspect, there is provided a scroll pump comprising an intake port, a scroll mechanism formed by a stator and a rotor, an intake cover, and an intake valve according to one aspect.

[0016] In some embodiments, the scroll pump includes a control circuit configured to control the actuator to move the sealing mechanism between the open and closed positions. The control circuit can be separate from the circuitry that controls the general operation of the motor and pump, or can be incorporated into the general control circuit that controls the motor that drives the pump.

[0017] In some embodiments, the control circuit is configured to control the actuator to move the sealing mechanism to a closed position in response to stopping the scroll pump. In this way, the scroll mechanism is no longer in fluid communication with the intake port and any additional pumps or process chambers to which the pump is attached. This can prevent fluid in the scroll pump from leaking into a lower-pressure environment, such as a pump or process chamber to which the scroll pump is connected. It should also be appreciated that this can mitigate fluid from flowing backward into the scroll pump when the scroll pump is connected to a higher-pressure environment.

[0018] In some embodiments, the control circuit may be configured to control the actuator to move the sealing mechanism to an open position in response to actuation of the pump.

[0019] In some embodiments, the control circuit can be configured to control the actuator to move the sealing mechanism to the open position at a predetermined time after the pump is actuated. Opening the intake valve immediately upon start-up, when the pressure within the scroll pump is atmospheric, can allow gas within the scroll pump to flow through the intake port into additional pumps and / or the environment being evacuated, such as a process chamber. Opening the intake valve after a predetermined time allows the scroll pump time to drain fluid within the pump and reduce pressure, thereby mitigating backflow into the pumped environment. Control circuitry providing a simple time delay is low-cost, reliable, and simple.

[0020] In some embodiments, the control circuitry may provide an adjustable time delay such that the predetermined time period can be varied in response to an input, such as an input provided by an operator. In this regard, the appropriate time delay may vary depending on the system being pumped and other factors, such as the presence or absence of an exhaust valve, and the adjustable time delay provides a flexible pump that can be configured to operate effectively under a variety of conditions.

[0021] In other embodiments, the control circuit may be configured to control the actuator to move to the open position in response to receiving a signal indicating that the pump is operating normally.

[0022] Some scroll pumps may include sensors and circuitry configured to generate a signal indicating that the pump is operating normally after startup. Such a signal can be used for safe operation of the scroll pump and to provide a warning if the pump is not operating normally. For example, this signal can be used to shut down the motor driving the pump before damage occurs if the control circuitry controlling the motor does not receive the signal within a predetermined time. Because this signal occurs after the pump has started and appears to be functioning normally, it is a very appropriate time to open the intake valve. Furthermore, using this signal to control when the intake valve opens after startup eliminates the need for additional circuitry to generate an additional control signal to control the opening of the intake valve, potentially reducing circuitry, reducing costs, and increasing pump reliability.

[0023] In some embodiments, the signal includes an indication that the pump has reached a predetermined rotational speed. The predetermined rotational speed can be, for example, a normal operating speed. Reaching the predetermined rotational speed is a good time to open the intake valve because the pressure in the pump drops when the pump reaches the predetermined rotational speed, reducing backflow when the intake valve is opened. The scroll pump can include a sensor that measures the rotational speed and sends a signal to the control circuit.

[0024] In some embodiments, the scroll pump further includes a first pressure sensor attached to the intake port and a second pressure sensor attached between the intake valve and the scroll mechanism, and the control circuit is configured to control the actuator to move the sealing mechanism to an open position when the pressure measured by the second pressure sensor is equal to or less than the pressure measured by the first sensor.

[0025] The provision of a pressure sensor reduces backflow into the process chamber or TMP to which the scroll pump is connected because the intake valve only opens when the pressure in the scroll mechanism is equal to or less than the pressure at the intake port. This provides an effective method of reducing or eliminating backflow, but requires an additional active component in the form of a pressure sensor.

[0026] In some embodiments, a control circuit is configured to control a motor configured to drive the scrolling mechanism. A control circuit within the pump generates and sends a control signal to the motor indicating that the motor should start, which can also be used to control the opening of the intake valve. In this manner, a unified control circuit can be used to control both the motor and the intake valve. This ensures synchronization between the two operations, reduces the need for additional components, and improves reliability.

[0027] Although the control circuit is described above with reference to controlling an intake valve according to one embodiment, such a control circuit can be used to control other types of intake valves located at the intake of a scroll pump.

[0028] In some embodiments, the scroll pump is a vacuum pump that can be used to evacuate process chambers for semiconductor manufacturing.

[0029] According to another aspect, there is provided a vacuum pumping system comprising a scroll pump according to the further aspect and a turbomolecular pump, the scroll pump being arranged as a backing pump for the turbomolecular pump.

[0030] Preventing backflow is particularly important when the scroll pump is used as a backing pump for a turbomolecular pump, because exposing the turbomolecular pump to higher pressures, such as atmospheric pressure, would significantly slow down the turbomolecular pump, which would adversely affect its pumping and could potentially damage the pump.

[0031] According to yet another aspect, a method of controlling an intake valve of a scroll vacuum pump is provided, the method including the steps of: supplying power to a motor driving a rotor of the scroll pump; determining whether an intake valve open condition is satisfied, the intake valve open condition including either the passage of a predetermined time period or receiving a control signal indicating that the rotor has reached a predetermined speed; and opening the intake valve of the scroll pump in response to the condition being satisfied.

[0032] In some embodiments, the intake valve is an intake valve according to one aspect.

[0033] According to a further aspect, there is provided a computer program comprising instructions operable, when executed by a processor of a scroll pump, to control said scroll pump to perform the steps of the method of yet another aspect.

[0034] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

[0035] It should be understood that when features of an apparatus are described as being operable to provide a certain function, this includes features of an apparatus that provide that function or that are adapted or configured to provide that function.

[0036] Embodiments of the present invention will now be further described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0037] [Figure 1] 1 illustrates a cross section of a scroll pump intake valve in a closed position according to one embodiment. [Figure 2A] 2 illustrates a cutaway view of the scroll pump intake valve of FIG. 1 in an open position. [Figure 2B] 2 illustrates a cutaway view of the scroll pump intake valve of FIG. 1 in a closed position. [Figure 3] 1 illustrates a vacuum pumping system according to one embodiment. [Figure 4] FIG. 2 is a flow diagram illustrating steps of a method according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0038] Before describing the embodiments in more detail, an overview will first be provided.

[0039] An embodiment provides a scroll pump intake valve in which a valve body is integrated into the pump stator or intake cover to save cost and space. The scroll pump intake valve includes a valve seat and a sealing mechanism or means for selectively sealing against the valve seat to block an intake passage defined between the scroll pump intake port and the scroll mechanism. The valve seat is formed from at least one of the scroll pump stator and intake cover. The sealing mechanism includes an actuator attached to the stator or intake cover and configured to move the sealing mechanism between an open position, in which the scroll mechanism is in fluid communication with the scroll pump intake port, and a closed position, in which the sealing mechanism engages the valve seat to seal the scroll mechanism from the intake port.

[0040] Incorporating the intake valve body into the scroll pump eliminates at least some of the fittings and reduces the extra space required for the valve. Solenoids can be used to actuate the valve because they are simple and inexpensive to operate. The valve body and valve seat can be machined into the scroll stator or intake cover. A sealing mechanism, which can include a solenoid actuator coil and armature, can be attached to the stator / intake cover to complete the assembly.

[0041] In use, the valve opens when the pump is running and closes when the pump is stopped. The valve coil can be connected to the motor power supply. A time delay circuit can be included to delay the opening of the valve for a few seconds, allowing the pump to accelerate to full speed and evacuate its own intake space before opening.

[0042] FIG. 1 shows a portion of a scroll pump 1 with an integrated intake valve 10. The intake valve 10 is located downstream of an intake port 18 of the scroll pump 1 and upstream of the scroll mechanism of the scroll pump 1 formed by a rotor 14 and a stator 12, as is known in the art. When the intake valve 10 is in an open position, it is configured to allow fluid to enter the scroll pump, as shown by arrow A. The scroll mechanism is enclosed by an intake cover 15 attached to the stator 12. The scroll pump 1 is a vacuum pump that can be used as a backing pump for a turbomolecular pump (TMP).

[0043] Intake valve 10 includes a valve seat 11, a valve body 16, and a sealing mechanism 13 having an actuator configured to move the sealing mechanism between an open position (shown in FIG. 2A) in which the scroll mechanism is in fluid communication with intake port 18 of scroll pump 1, and a closed position (shown in FIGS. 1 and 2B) in which sealing mechanism 13 engages valve seat 11 to seal the scroll mechanism from intake port 18.

[0044] In this embodiment, intake valve 10 is incorporated into scroll pump 1 by forming valve seat 11 and valve body 16 within stator 12. Valve seat 11 is formed by the outer periphery of a portion of the intake passageway that extends into space 17 defined by valve body 16 and sealing mechanism 13. Space 17 defines a portion of the intake passageway. When sealing mechanism 13 is in the open position, sealing mechanism 13 is configured to cooperate with stator 12, particularly valve body 16, to define a portion of the intake passageway that includes space 17. When sealing mechanism 13 is in the closed position, sealing mechanism 13 is disposed within space 17 and seals against valve seat 11.

[0045] The valve seat 11 and valve body 16 are machined into the stator 12. It should be understood that the valve seat 11 and valve body 16 do not have to be machined but can be manufactured using any suitable technique, such as additive manufacturing, to create a flow path between the intake port 18 and the scroll mechanism via the sealing mechanism 13. It should also be understood that some or all of the intake port 18, the valve seat 11, and the valve body 16 can be defined in the intake cover 15 rather than the stator 12.

[0046] The sealing mechanism 13 further comprises an attachment means 23 configured to attach the sealing mechanism 13 to the stator 12. The attachment means 23 may comprise a threaded structure configured to mate with a complementary structure defined on the stator 12. The attachment means 23 may comprise a seal, such as an O-ring, to create a fluid-tight seal. It should be understood that when the sealing mechanism is attached to the valve body 16, any attachment means that creates a fluid-tight seal between the valve body 16 and the sealing mechanism 13 may be used. For example, a push-fit or snap-fit ​​attachment means may be used.

[0047] Intake valve 10 is a magnetically actuated valve. The actuator of sealing mechanism 13 includes a solenoid coil configured to move armature 20 such that, in the closed position, a rubber pad 22 (shown in FIG. 2) attached to the end of armature 20 engages valve seat 11, and in the open position, rubber pad 22 and armature 20 move away from valve seat 11 to form an intake passage that defines a flow path between intake port 18 and the scroll mechanism.

[0048] In this embodiment, there are also pressure sensors 26 and 27 for sensing the pressure on either side of intake valve 10. In some embodiments, these can send a signal to a control circuit (not shown) that controls valve opening. In this way, valve opening can be controlled to occur when the pressure on the pump side of intake valve 10 is equal to or less than the pressure on the other side of intake valve 10.

[0049] 2A shows that the armature supports a rubber pad 22 for sealing against the valve seat 11 when in the closed position to prevent fluid flow between the intake port 18 and the scroll mechanism. The portion of the armature 20 that includes the rubber pad 22 is biased toward the valve seat 11 by a biasing member 21 that includes a coil spring to help create and maintain a fluid-tight seal when the sealing mechanism 13 is in the closed position. It should be understood that the entire armature can be biased to achieve substantially the same effect.

[0050] Figure 2B shows how the intake valve sealing mechanism 13 is secured to the pump by mounting means 23. The valve seat 11 is located within a stator 12. The sealing mechanism comprises an armature 20 for driving the sealing mechanism 13 towards an open position and biasing means 21 for biasing the sealing mechanism towards a closed position when the armature is not driven. Figure 2B shows the sealing mechanism in the closed position.

[0051] FIG. 3 illustrates a schematic diagram of a vacuum pump system including a scroll pump 1 supplemented by a turbomolecular pump 34. The scroll pump 1 includes an intake valve 10 incorporated within a scroll pump mechanism 36, which includes at least a stator 12 and a rotor 14. The scroll pump 1 also includes a control circuit 30 configured to control an actuator to move a seal mechanism 13 of the intake valve 10 between an open position and a closed position. The control circuit 30 also controls a motor 32 to drive the scroll pump rotor. The control circuit 30 can coordinate the starting of the motor and the opening of the intake valve. In some embodiments, the control circuit 30 can receive a signal from a sensor associated with the scroll pump indicating when a predetermined rotational speed of the rotor has been achieved after starting. This signal can be used by the control circuit 30 to determine whether the pump is operating normally, and if this signal is not received within a predetermined time, the control circuit 30 can shut down the motor 32.

[0052] The motor 32 is configured to drive the rotor 14. Additionally, the actuator of the sealing mechanism 13 may be connected to the power supply of the motor 32 or may have its own power supply.

[0053] In this embodiment, the scroll pump 1 is used as a backing pump for the TMP34.

[0054] In use, the control circuit 30 of the scroll pump 1 controls the actuator to move the seal mechanism 13 to an open position in response to operation of the pump 1 to allow normal pump operation. The intake valve 10 can be opened immediately upon operation of the pump 1, or preferably some time thereafter, to allow residual fluid within the pump to be evacuated before the scroll mechanism is placed in fluid communication with the TMP or process chamber to which the scroll pump 1 is attached. In this way, backflow into the TMP or process chamber is mitigated. This can be accomplished by opening the intake valve 10 a predetermined time after operation of the pump 1 or after the control circuit 30 receives a signal indicating that the pump 1 is operating normally. This signal can indicate that the pump 1 has reached a predetermined rotational speed. Alternatively, this can be accomplished using pressure sensors, as shown in the embodiment of FIG. 1. In this embodiment, the scroll pump includes a first pressure sensor 26 attached to the intake port 18 and a second pressure sensor 27 attached to a portion of the intake passage between the intake valve 10 and the scroll mechanism (i.e., on the opposite side of the intake valve from the first pressure sensor). The control circuit 30 is configured to control the actuator to move the seal mechanism 13 to the open position when the pressure measured by the second pressure sensor 27 is equal to or less than the pressure measured by the first sensor 26. This ensures that the pressure within the scroll mechanism is equal to or less than the pressure at the intake port 18 before opening the intake valve 10. In this way, backflow of fluid through the intake port 18 toward the connected process chamber or TMP can be mitigated.

[0055] When the scroll pump 1 is stopped, the control circuit 30 controls the actuator to move the seal mechanism 13 to a closed position, preventing fluid movement between the TMP or process chamber and the scroll mechanism, thus preventing backflow from the scroll mechanism to the low-pressure TMP or process chamber.

[0056] FIG. 4 is a flow diagram illustrating steps in a method for actuating an intake valve of a scroll pump according to one embodiment. Initially, in step S10, a control signal is received to start the pump. Next, in S20, power is applied to the pump motor. In step D5, it is determined whether an intake valve opening condition has been met. The opening condition may be the passage of a predetermined time or the receipt of a normal operating condition signal. The normal operating condition signal may be generated in response to the rotor reaching a predetermined speed within a predetermined time after start-up. In response to determining that this operating condition has been met, step S30 is executed to open the intake valve. Because the predetermined time may be adjustable, in some embodiments, pump setup may include an initial step of setting the predetermined time to a value appropriate for the particular planned operation of the pump.

[0057] In other embodiments, there may be no such intake valve opening condition, and the intake valve may simply open in response to a control signal starting the pump. This has the advantage of simplicity, but the disadvantage that the pump will be at or near atmospheric pressure when initially connected to the chamber being pumped, which may be at a high vacuum.

[0058] The scroll pump will then operate normally until a signal to stop the motor is received in S40, in response to which the intake valve may be closed in step S50.

[0059] The control circuit 30 of FIG. 3 may be configured to generate a control signal for controlling the operation of the intake valve according to the steps of the method described in FIG.

[0060] Various modifications to the embodiments described herein will be apparent to those skilled in the art. For example, the rubber pad 11 can be any surface suitable for sealing with the valve seat 11. Also, the biasing member 21 need not be a coil spring but can be any suitable biasing member configured to bias the armature 20 toward the valve seat 11 when in the closed position.

[0061] In summary, the valve body 16 is integrated into the pump stator 12 to save cost and space. The intake valve body 16 is integrated into the scroll pump 1, eliminating fittings and reducing the extra space required for a separate, external intake valve. The intake valve 10 can be a magnetically actuated valve, such as a solenoid valve. Solenoid valves are used due to their simple operation and low cost. The valve body 16 and valve seat 11 are machined into the scroll stator 12 or intake cover 15.

[0062] In use, valve 10 opens when pump 1 is running and closes when pump 1 is stopped. The valve coil (sealing mechanism 13) can be connected to the motor power supply for pump 1. A time delay circuit, referred to above as the control circuit, can be included to delay the opening of valve 10 by a few seconds to allow pump 1 to accelerate to full speed and evacuate the intake space of pump 1 before opening valve 10.

[0063] Although exemplary embodiments of the present invention have been disclosed in detail herein with reference to the accompanying drawings, it is understood that the present invention is not limited to the precise embodiments, and that various changes and modifications can be made by those skilled in the art without departing from the scope of the present invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0064] 1 Scroll pump 10 Intake valve 11 Valve seat 12 Stator 13 Sealing mechanism 14 rotors 15 Intake cover 16 Valve body 17 Space 18 Intake port 20 Armature 21 biasing member 22 pads 23 Mounting means 25 Pump housing 26, 27 Pressure sensor 30 Control circuit 32 motor 34 Turbomolecular pump 36 Scroll pump mechanism

Claims

1. a valve seat formed by at least one of a stator and an intake cover of the scroll pump; a sealing mechanism attached to the stator or the intake cover; An intake valve for a scroll pump comprising: The sealing mechanism includes: an intake valve comprising an actuator configured to move a sealing mechanism between an open position in which a scroll mechanism is in fluid communication with an intake port of the scroll pump and a closed position in which the sealing mechanism engages the valve seat to seal the scroll mechanism from the intake port.

2. 2. The intake valve of claim 1, wherein the sealing mechanism is configured to cooperate with at least one of the stator and the intake cover to define a portion of an intake passage of the scroll pump when the sealing mechanism is in the open position, the intake passage defining a flow path between the intake port and the scroll mechanism.

3. 3. The intake valve according to claim 2, wherein the valve seat is formed by an outer periphery of a portion of the intake passage.

4. The intake valve of claim 1 , wherein the actuator comprises a solenoid coil.

5. 5. The intake valve according to claim 1, wherein the intake valve comprises a valve body and the valve seat, the valve body and the valve seat being formed by at least one of the intake cover and the stator.

6. Intake port and a scroll mechanism formed by a stator and a rotor; Intake cover and An intake valve according to any one of claims 1 to 5; A scroll pump comprising:

7. The scroll pump of claim 6 , further comprising a control circuit configured to control the actuator to move the sealing mechanism between the open position and the closed position.

8. The scroll pump of claim 7 , wherein the control circuit is configured to control the actuator to move the sealing mechanism to the closed position in response to stopping of the scroll pump.

9. 9. The scroll pump of claim 7, wherein the control circuit is configured to control the actuator to move the sealing mechanism to the open position in response to operation of the scroll pump.

10. 10. The scroll pump of claim 7, wherein the control circuit is configured to control the actuator to move the sealing mechanism to the open position at a predetermined time after the scroll pump is actuated.

11. 10. The scroll pump of claim 7, wherein the control circuit is configured to control the actuator to move the sealing mechanism to the open position in response to receiving a signal indicating that the scroll pump is operating normally.

12. 12. The scroll pump of claim 11, wherein the signal includes an indication that the scroll pump has reached a predetermined rotational speed.

13. The scroll pump comprises: a first pressure sensor attached to the intake port; a second pressure sensor mounted between the intake valve and the scroll mechanism; Furthermore, 9. The scroll pump of claim 7, wherein the control circuit is configured to control the actuator to move the sealing mechanism to the open position when the pressure measured by the second pressure sensor is equal to or less than the pressure measured by the first pressure sensor.

14. 14. The scroll pump of claim 7, wherein the control circuit is configured to control a motor configured to drive the scroll mechanism.

15. 15. The scroll pump according to claim 6, wherein the scroll pump is a vacuum pump.

16. 16. A vacuum pump system comprising the scroll pump according to claim 6 and a turbomolecular pump, wherein the scroll pump is arranged as a backing pump for the turbomolecular pump.

17. 1. A method for controlling an intake valve of a scroll vacuum pump, comprising: providing power to a motor that drives a rotor of the scroll vacuum pump; determining whether an intake valve opening condition has been met, the intake valve opening condition including either a predetermined time period having elapsed or a control signal being received indicating that the rotor has reached a predetermined speed; opening the intake valve of the scroll vacuum pump in response to the intake valve opening condition being satisfied; A method comprising:

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