Bellows diaphragm assembly

Abstract

A diaphragm assembly for a mass flow controller is disclosed. [Solution] The diaphragm assembly comprises an opening, side walls extending from the opening and positioned around a central axis, including a plurality of ripples, and a poppet including an inner and outer sealing surface facing the opening. At least a portion of the diaphragm assembly is movable and extendable within the control valve cavity of the mass flow controller. A pushrod extending from the inner surface of the poppet moves in response to an actuator of the mass flow controller, allowing the outer sealing surface of the poppet to open and close the flow path through the control valve cavity.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to systems and methods for mass flow control, and more specifically to diaphragms for mass flow controllers.

Background Art

[0002] Mass flow controllers are used to regulate the mass flow of gas to a desired position. For example, some mass flow controllers accurately adjust mass flow in environments where process gas is delivered for processing applications, such as in plasma processing systems. When regulating mass flow, such mass flow controllers often utilize deflection of a diaphragm along a gas flow path, also known as a "wetted part".

[0003] Diaphragms for mass flow controllers often comprise a thin circular sheet of metal typically 25 mm or more in diameter, which can accommodate large deflection (e.g., 60 to 100 microns). However, mass flow controllers with a smaller footprint require smaller diameter diaphragms, which cannot accommodate the large deflection required for certain applications.

[0004] There is increasing demand for such smaller-footprint mass flow controllers, and therefore new diaphragm designs are needed in the art that address some of the current drawbacks, particularly those associated with maintaining large deflection capacity with smaller diameter diaphragms.

Summary of Invention

[0005] The following provides a simplified overview of one or more aspects and / or embodiments disclosed herein. Therefore, the following overview should not be considered a broad overview relating to all possible aspects and / or embodiments, nor should it be considered to identify important or significant elements relating to all possible aspects and / or embodiments, or to describe the scope relating to any particular aspect and / or embodiment. Accordingly, the following overview is intended solely to provide a simplified overview of certain concepts relating to one or more aspects relating to the mechanisms disclosed herein, prior to the detailed description presented below.

[0006] Some aspects of this disclosure may be characterized as a mass flow controller having a flow path including a control valve cavity having a control valve cavity inlet port and a control valve cavity outlet port. The mass flow controller comprises a mass flow meter configured to measure the mass flow rate of a gas flowing through the flow path, a controller configured to provide an actuator control signal in response to a mass flow signal from the mass flow meter, and an actuator configured to move in response to the actuator control signal. The mass flow controller further comprises a diaphragm assembly configured to extend and retract so as to be movable within the control valve cavity, at least in part. The diaphragm assembly comprises an opening, a side wall extending from the opening and arranged around a central axis and including a plurality of ripples, and a poppet including an inner surface facing the opening and an outer sealing surface facing the control valve cavity inlet port. A push rod may extend from the inner surface of the poppet along the central axis through an opening into which the push rod can be coupled to an actuator. The push rod may move along the central axis in response to the movement of the actuator, and the outer sealing surface of the poppet may open and close the flow path through the control valve cavity.

[0007] Other aspects of the present disclosure may be characterized as a mass flow controller having a flow path including a control valve cavity having a control valve cavity inlet port and a control valve cavity outlet port. The mass flow controller may include a mass flow meter configured to measure the mass flow rate of a gas flowing through the flow path, a controller configured to provide an actuator control signal in response to a mass flow signal from the mass flow meter, and an actuator configured to move in response to the actuator control signal. The mass flow controller may further include a diaphragm assembly, the diaphragm assembly may include means for sealing the control valve cavity away from the actuator, means for opening and closing the flow path through the control valve cavity, and a bellows coupled between the sealing means and the opening and closing means. A push rod may couple the diaphragm assembly to the actuator so that the diaphragm assembly moves in response to the actuator. [Brief explanation of the drawing]

[0008] [Figure 1] A cross-sectional view of an exemplary embodiment of a mass flow controller with a diaphragm assembly is shown. [Figure 2] Figure 1 shows an enlarged cross-sectional view of the normally open control valve assembly of the mass flow controller, with a diaphragm assembly having a formed flanged top surface. [Figure 3] A cross-sectional view of an exemplary embodiment of a normally-open control valve assembly for a mass flow controller, with a diaphragm assembly having a separately coupled flanged top surface, is shown. [Figure 4] A cross-sectional view of an exemplary embodiment of a normally-closed control valve assembly of a mass flow controller, including a diaphragm assembly and a biasing spring, is shown. [Figure 5] A cross-sectional view of an exemplary embodiment of a normally-closed control valve assembly for a mass flow controller, with a diaphragm assembly having an integrated pushrod, is shown. [Figure 6]A cross-sectional view of an exemplary embodiment of a normally open control valve assembly for a mass flow controller is shown, with a diaphragm assembly having a formed poppet integrated with a clamp block. [Figure 7] A cross-sectional view of an exemplary embodiment of a normally-open control valve assembly for a mass flow controller is shown, with a diaphragm assembly having a separately coupled poppet integrated with a clamp block. [Figure 8A] A cross-sectional view of an exemplary embodiment of a diaphragm assembly having a formed flanged upper surface is shown. [Figure 8B] A cross-sectional view of an exemplary embodiment of a diaphragm assembly having a separately coupled flanged top surface is shown. [Figure 9A] A cross-sectional view of an exemplary embodiment of a diaphragm assembly having an integrated push rod and a formed flanged upper surface is shown. [Figure 9B] A cross-sectional view of an exemplary embodiment of a diaphragm assembly having an integrated push rod and a separately coupled flanged upper surface is shown. [Modes for carrying out the invention]

[0009] The term “exemplary” is used herein to mean “serving as an example, illustration, or representation.” Any embodiment described herein as “exemplary” should not necessarily be construed as being preferable or advantageous to other embodiments.

[0010] This disclosure may enable a small-diameter diaphragm (e.g., 7–9 mm) of a mass flow controller to have a potentially large deflection capacity (e.g., 40–60 microns), thereby enabling mass flow control at higher flow rates (e.g., 20 standard liters per minute (SLM)) than previously possible. Furthermore, this disclosure may enable the removal of certain typical mass flow controller components, such as springs and pushrods of a typical control valve assembly, from the gas-contacting parts, potentially preventing corrosion or other degradation of such components associated with gas exposure. Moreover, this disclosure may enable the control valve assembly of a mass flow controller to operate without requiring a spring that was conventionally associated with the control valve. Implementing the device of this disclosure may result in significant improvements to the mass flow controller, potentially enabling a more reliable mass flow controller with a smaller footprint.

[0011] Some embodiments of the present disclosure may include a mass flow controller having a flow path including a control valve cavity with an inlet port and an outlet port. The mass flow controller may further include a mass flow meter configured to measure the mass flow rate of gas flowing through the flow path, and a controller configured to provide an actuator control signal in response to a mass flow signal from the mass flow meter. The mass flow controller may further include an actuator configured to move in response to the actuator control signal. The actuator may be implemented, for example, by a piezoelectric, a solenoid, or other actuator known in the art. The mass flow controller may further include a diaphragm assembly configured to extend and retract so as to be movable within the control valve cavity, which may enable control of the gas flow through the flow path. The diaphragm assembly may include an opening, a side wall extending from the opening and positioned around a central axis and including a plurality of ripples, and a poppet including an inner surface facing the opening and an outer sealing surface facing the inlet port. The side wall with a plurality of ripples may also be referred to as a bellows. Such unique diaphragm assembly designs, referred to herein as “bellows diaphragm assemblies” (or more simply “diaphragm assemblies”), can enable greater deflection with a smaller diameter than conventional diaphragm assemblies. The mass flow controller may further include a pushrod extending from the inner surface of the poppet along the central axis through an opening through which the pushrod can be coupled to an actuator. The pushrod moves along the central axis in response to the movement of the actuator, causing the outer sealing surface of the poppet to open and close a flow path through the control valve cavity, providing a means for opening and closing the flow path through the control valve cavity.

[0012] In some embodiments, the diaphragm assembly may include a flanged top surface configured to seal the control valve cavity, thereby controlling and maintaining the pressure within the flow path. Furthermore, the seal provided by the flanged top surface may allow the push rod and other mass flow controller components to be protected from exposure to the gas in the flow path, potentially preventing corrosion or other gas-related degradation. Thus, the flanged top surface may provide a means for sealing the control valve cavity away from the actuator, and a bellows may be connected between the sealing means, such as the flanged top surface, and the means for opening and closing the flow path through the control valve cavity, such as the outer sealing surface of a poppet. The flanged top surface and the poppet, respectively, may be formed as a component integrated with the side wall of the diaphragm assembly, or alternatively, they may be machined parts bonded to the side wall of the diaphragm assembly, such as by welding, with the flanged top surface bonded close to the opening and the poppet bonded to the end opposite the opening.

[0013] In some embodiments, the inner surface of the poppet may include a recess, such as a conical notch, configured to receive a push rod. Such a recess may potentially improve the reliability of the mass flow controller by preventing lateral movement of the push rod that could interfere with proper valve closure.

[0014] In other embodiments, the pushrod may be integrated with the inner surface of the poppet, thereby forming a single part. Integrating the pushrod, as with the poppet recess described above, can potentially improve reliability by preventing lateral pushrod movement, and can also enable a simpler, more robust structure by reducing the number of parts, potentially limiting error propagation associated with the combination of individually manufactured parts.

[0015] In some embodiments, the rotation of the diaphragm assembly, i.e., the bellows, can be configured to deform along the central axis of the diaphragm assembly, and when deformed, exert a restoring force. This restoring force can fix the poppet in its default resting position, provided it is not disturbed by other forces, such as a pushrod. As a result, the diaphragm assembly itself can function as a spring within the mass flow controller, allowing the mass flow controller to operate without the additional springs conventionally associated with the control valve. The spring-like function of the diaphragm assembly can be used in some embodiments to enable various configurations with improved functionality, such as a configuration in which the diaphragm assembly exerts a spring and a reverse restoring force to enhance the tendency of the diaphragm assembly to return to its default resting position. The geometry of the wall thickness, torsion, and rotation can be modified to achieve specific effective spring constants. The restoring force of the diaphragm assembly can be used, for example, as a compression or expansion spring force, depending on the application and mass flow controller design.

[0016] In some embodiments, the outer sealing surface of the poppet may be positioned in a default resting position such that the flow path through the control valve cavity is normally open. For example, the resting position of the outer sealing surface of the poppet may be a retracted state, leaving an unobstructed flow path between the inlet and outlet ports of the control valve cavity. A push rod may push the poppet out into an extended state, obstructing the flow path between the inlet and outlet ports of the control valve cavity with the outer sealing surface of the poppet. When the force from the push rod decreases to a normal level, the outer sealing surface of the poppet returns to its default resting position, and the flow path through the control valve cavity may return to its normally open state.

[0017] In other embodiments, the outer sealing surface of the poppet may be positioned in a default resting position so that the flow path through the control valve cavity is normally closed. For example, the resting position of the outer sealing surface of the poppet may be an extended state that obstructs the flow path between the inlet and outlet ports of the control valve cavity. The force applied to the poppet by the pushrod may decrease, thereby causing the outer sealing surface of the poppet to retract, leaving an unobstructed flow path between the inlet and outlet ports of the control valve cavity. When the force from the pushrod increases to a normal level, the outer sealing surface of the poppet may extend back to its default resting position, and the flow path through the control valve cavity may return to its normally closed obstructed state.

[0018] Referring here to the drawings, Figure 1 shows a cross-sectional view of an exemplary embodiment of a mass flow controller 100 with a diaphragm assembly 130. The mass flow controller 100 may have a flow path that receives gas through a mass flow controller inlet port 102 and allows the gas to flow into a bypass portion 104 of the mass flow controller 100, a portion of which is diverted to a mass flow meter 106 and then rejoined downstream into the main flow path of the gas. When the flow path through the control valve cavity 110 is open and unobstructed, the gas may proceed along the flow path through the bypass portion outlet port 108 to the control valve cavity inlet port 109 and enter the control valve cavity 110. The gas may then proceed along the flow path through the control valve cavity outlet port 111 and exit the mass flow controller 100 through the mass flow controller outlet port 112.

[0019] The flow of gas along the flow path can be adjusted using a control valve assembly of a mass flow controller 100, which may comprise an actuator 114, a motion booster assembly 116, a push rod 118, a clamp block 120, and a diaphragm assembly 130. The control valve assembly may be coupled to a mass flow controller base plate 122. The mass flow meter 106 may be configured to measure the mass flow rate of gas flowing through the flow path and output a mass flow rate signal 125 based on the mass flow rate of the gas. The controller 126 of the mass flow controller 100 may be configured to respond based on the mass flow rate signal 125 from the mass flow meter 106 and provide an actuator control signal 127 to the actuator 114. A mass flow rate setpoint 128 may be communicated to the controller 126 via a mass flow rate setpoint signal 129, and the controller 126 may compare the mass flow rate signal 125 with the mass flow rate setpoint signal 129 to determine an appropriate actuator control signal 127 and transmit the same to the actuator 114. The actuator 114 may be configured to move in response to the actuator control signal 127, and may be implemented by, for example, a piezoelectric actuator, a solenoid, or other actuators known in the art. The actuator 114 may interface with the motion booster assembly 116, which can amplify the movement of the actuator 114 and transmit the amplified movement to the push rod 118. The push rod 118 may interface with the diaphragm assembly 130 to provide a force that can extend the diaphragm assembly 130 from a normally open retracted state.

[0020] Figure 2 shows an enlarged cross-sectional view of the normally open control valve assembly 200 of the mass flow controller 100 in the exemplary embodiment of Figure 1, where the diaphragm assembly 130 has a flanged top surface 236, which may be formed as a single unit. The diaphragm assembly 130 may comprise an opening 231, a side wall 234 extending downward from the opening 231 and positioned around a central axis, including a plurality of ripples forming a bellows, and a poppet 232 including an inner surface facing the opening 231 and an outer sealing surface facing the control valve cavity inlet port 109. The diaphragm assembly 130 may be configured so that at least a portion thereof is movable and expandable within the control valve cavity 110, thereby enabling control of the gas flow through the passage. The design of the diaphragm assembly 130 may allow for greater deflection with a smaller diameter than conventional sheet metal diaphragm assemblies. The push rod 118 may extend from the inner surface of the poppet 232 along its central axis through the opening 231, and the push rod 118 may be coupled to the actuator 114 via a motion booster assembly 116, which may amplify and transmit the movement of the actuator 114 to the push rod 118 via a hinge-like mechanism. The actuator 114 and the push rod 118 may interface with the motion booster assembly 116, which has a rounded surface, and the motion booster assembly 116 may pivot without generating excessive stress through such interface. The push rod 118 moves along its central axis in response to the movement of the actuator 114, which may allow the external sealing surface of the poppet 232 to open and close the flow path through the control valve cavity 110, providing a means for opening and closing the flow path through the control valve cavity 110.

[0021] The diaphragm assembly 130 can include a flanged top surface 236, which is configured to seal the control valve cavity 110 and can control and maintain the pressure in the flow path. Further, the seal provided by the flanged top surface 236 can enable the push rod 118 and other mass flow controller components to be protected from exposure to gas in the flow path, potentially preventing corrosion or other gas-related degradation. Therefore, the flanged top surface 236 can provide a means for sealing the control valve cavity 110 separately from the actuator 114 and the motion booster assembly 116. The side wall 234, i.e., the bellows, can be coupled between a sealing means such as the flanged top surface 236 and a means for opening and closing the flow path through the control valve cavity, such as the external sealing surface of the poppet 232. The illustrated flanged top surface 236 is formed as an integrated part with the side wall 234 adjacent to the opening 231, while the poppet 232 can be a separate part such as a machined part coupled to the side wall 234 at the end opposite the opening 231, such as by welding. The inner surface of the poppet 232 can include a recess such as a conical notch configured to receive the push rod 118 which can have a rounded end. Such a recess can potentially increase the reliability of the mass flow controller 100 by preventing lateral movement of the push rod 118 that could interfere with proper valve closing. However, other embodiments can potentially feature various push rod geometries, for example, a push rod with a flat end that can directly interface with the poppet without a recess.

[0022] The diaphragm assembly 130 may be seated within the control valve cavity 110 and fixed in place between the clamp block 120 and the mass flow controller base plate 122. The flanged top surface 236 of the diaphragm assembly 130 may be seated within the orifice of the mass flow controller base plate 122 and held in place by a projection of the clamp block 120 that extends into the orifice and presses the flanged top surface 236 into the lip within the orifice, thereby ensuring a seal of the control valve cavity 110. An O-ring, such as a metal O-ring, may be placed between the clamp block 120 and the mass flow controller base plate 122 within the orifice. The clamp block 120 may include a recess configured to receive a push rod 118 and may be coupled to the mass flow controller base plate 122, for example, via screws or other fasteners.

[0023] The rotation, or bellows, of the side wall 234 of the diaphragm assembly 130 can be configured to deform along the central axis of the diaphragm assembly 130 and exert a restoring force during deformation. This restoring force can bias the poppet 232 to the normally open resting position, provided it is not disturbed by other forces, such as via the push rod 118. As a result, the diaphragm assembly 130 itself can function as a spring within the mass flow controller 100, allowing the mass flow controller 100 to operate without the additional springs conventionally associated with the control valve. The wall thickness, torsion, and rotation geometry of the side wall 234 can be modified to achieve a specific effective spring constant.

[0024] The resting position of the outer sealing surface of the poppet 232 may be in a normally open, retracted state, thereby the flow path through the control valve cavity 110 between the control valve cavity inlet port 109 and the control valve cavity outlet port 111 is in a normally open, unobstructed state, while the diaphragm assembly 130 is shown in an extended, closed state, which is the resting position that is not open. The push rod 118 can push the poppet 232 into such an extended state, obstructing the flow path between the control valve cavity inlet port 109 and the control valve cavity outlet port 111 to the outer sealing surface of the poppet 232. In some examples, the outer sealing surface of the poppet 232 may be fully extended to interface with the control valve cavity inlet port 109, preventing any flow through the control valve cavity 110. As the force provided by the pushrod 118 decreases to a normal resting level, the outer sealing surface of the poppet 232 may return to its normally open resting position, and the restoring force of the diaphragm assembly 130 causes the outer sealing surface of the poppet 232 to retract, allowing the flow path through the control valve cavity 110 to return to its normally open state. The flow of gas through the mass flow controller 100 can be regulated by controlling this expansion and contraction of the diaphragm assembly 130 via the actuator 114.

[0025] Referring here to Figure 3, a cross-sectional view of an exemplary embodiment of a normally open control valve assembly 300 of a mass flow controller, with a diaphragm assembly 330 having a separately coupled flanged top surface 336. The control valve assembly 300 in Figure 3 is substantially the same as the control valve assembly 200 shown in Figure 2, except for the flanged top surface 336 of the diaphragm assembly 330 and the clamp block 320. In particular, the flanged top surface 336 and the poppet 332 of the diaphragm assembly 330 are separate parts, such as machined parts, which are coupled to the side wall 334 of the diaphragm assembly 330, for example by welding, with the flanged top surface 336 positioned close to the opening 331 and the poppet 332 positioned at the end opposite the opening 331. The resulting flanged top surface 336 has a greater thickness than the formed flanged top surface 236 in the embodiment of Figure 2. As a result, the opening 331 is slightly more elongated compared to the opening 231 in the embodiment of Figure 2. Furthermore, the clamp block 320 applies pressure to the thicker flanged top surface 336 in place by applying pressure to its flat bottom surface, rather than to the protruding portion of the clamp block 120 as in the embodiment of Figure 2, thereby ensuring a seal over the control valve cavity 110. This sealing configuration of the flanged top surface 336 may allow for the control and maintenance of pressure within the flow path. Moreover, the seal provided by the flanged top surface 336 may allow the push rod 118 and other mass flow controller components to be protected from exposure to gases within the flow path, potentially preventing corrosion or other gas-related degradation. Thus, the flanged top surface 336 may provide a means for sealing the control valve cavity 110 away from the actuator 114 and the motion booster assembly 116. In all other embodiments, the embodiment in Figure 3 is identical to the embodiment in Figure 2.

[0026] Referring here to Figure 4, a cross-sectional view of an exemplary embodiment of a normally closed control valve assembly 400 of a mass flow controller, with a diaphragm assembly 130 and a biasing spring 424, is shown. The control valve assembly 400 in Figure 4 is largely identical to the control valve assembly 200 shown in Figure 2, except for the normally closed arrangement of the control valve assembly 400, which is achieved by a different motion booster assembly 416 with the associated biasing spring 424 and a slightly different control valve cavity inlet port 409 contained within the mass flow controller base plate 422. The control valve cavity inlet port 409 is substantially identical to the control valve cavity inlet port 109 shown in the embodiment of Figure 2, except that the control valve cavity inlet port 409 features an additional ridge adjacent to the bypass portion outlet port 108. The control valve cavity inlet port 409 may be flat or have an additional ridge. The additional ridge is another way of creating a sealing surface. The additional protrusions increase the pressure between the poppet 232 and the control valve cavity inlet port 409 by reducing the contact area.

[0027] The motion booster assembly 416 interfaces with the push rod 118 and actuator 114 on both sides of the pivot point 417, allowing the movement of the actuator 114 to be amplified and transmitted to the push rod 118 via a lever-like mechanism, thereby changing the force applied to the poppet 232 by the push rod 118. For example, if the actuator 114 extends or moves downward and a force is applied to the motion booster assembly 416 on the right side of the pivot point 417, the force applied to the push rod 118 via the motion booster assembly 416 decreases as the portion of the motion booster assembly 416 on the left side of the pivot point 417 pivots upward, allowing the push rod 118 to move upward along the central axis of the diaphragm assembly 130. The push rod 118 can move along the central axis of the diaphragm assembly 130 in response to the movement of the actuator 114, allowing the external sealing surface of the poppet 232 to open and close the flow path through the control valve cavity 110, providing a means for opening and closing the flow path through the control valve cavity 110.

[0028] The motion booster assembly 416 may interface with a biasing spring 424 located adjacent to the push rod 118 and to the left of the pivot point 417. The motion booster assembly 416 may have an upwardly extending projection into the central recess of the biasing spring 424, thereby allowing the biasing spring 424 to maintain its position over time during operation. The biasing spring 424 may be attached to the wall of the control valve assembly 400 at the end opposite to the motion booster assembly 416 and, when deformed, may exert a restoring force on the upper surface of the motion booster assembly 416. For example, the biasing spring 424 may bias the outer sealing surface of the poppet 232 toward a normally closed extended resting state by applying a downward force to the motion booster assembly 416, and when compressed, the outer sealing surface of the poppet 232 retracts from the extended resting state. The force applied by the biasing spring 424 can be transmitted to the poppet 232 via the pushrod 118 and the motion booster assembly 416. The actuator 114 can counteract the force applied by the biasing spring 424 via the motion booster assembly 416 by retracting the external sealing surface of the poppet 232 and opening the normally closed passage through the control valve cavity 110. Furthermore, the spring-like function of the diaphragm assembly 130 can also be utilized to cooperate with the biasing spring 424 associated with the motion booster assembly 416, for example, in a configuration in which the biasing spring 424 and the diaphragm assembly 130 exert opposing restoring forces, increasing the tendency for the diaphragm assembly 130 and the external sealing surface of the poppet 232 to return to their default resting positions. Alternatively, the biasing spring 424 and the diaphragm assembly 130 may be configured to exert a non-counter-responding restoring force that reduces the load applied to both the biasing spring 424 and the diaphragm assembly 130, potentially extending the lifespan of both components.

[0029] The stationary position of the outer sealing surface of the poppet 232 may be positioned in a normally closed extended state, thereby obstructing the flow path through the control valve cavity 110 between the control valve cavity inlet port 409 and the control valve cavity outlet port 111 in a normally closed state as shown. In some examples, the outer sealing surface of the poppet 232 may be fully extended to interface with the control valve cavity inlet port 409, preventing any flow through the control valve cavity 110. The force applied to the poppet 232 by the push rod 118 may be reduced, for example, by the movement of the actuator 114 transmitted to the push rod 118 via the motion booster assembly 416, thereby retracting the outer sealing surface of the poppet 232 and leaving an unobstructed flow path between the control valve cavity inlet port 409 and the control valve cavity outlet port 111. The external sealing surface of the poppet 232 can extend and return to its normally closed resting position when the force provided by the pushrod 118 increases to a normal resting level, such as when the force applied to the motion booster assembly 416 by the actuator 114 decreases as the actuator 114 moves upward or retracts. A restoring force from at least one of the biasing spring 424 and the diaphragm assembly 130 can extend the external sealing surface of the poppet 232, returning the flow path through the control valve cavity 110 to its normally closed inhibited state. The gas flow can be regulated by controlling this extension and contraction of the diaphragm assembly 130 via the actuator 114.

[0030] Referring here to Figure 5, a cross-sectional view of an exemplary embodiment of a normally closed control valve assembly 500 of a mass flow controller, with a diaphragm assembly 530 having an integrated push rod 539. The control valve assembly 500 in Figure 5 is substantially the same as the control valve assembly 400 shown in Figure 4, except for the diaphragm assembly 530 having an integrated push rod 539, a slightly different motion booster assembly 516 design, the absence of a biasing spring, and the control valve cavity inlet port 109 being identical to the control valve cavity inlet port 109 shown in the embodiment of Figure 2.

[0031] The diaphragm assembly 530 may have an integrated push rod 539 integrated with the inner surface of the poppet 532, thereby forming a single part. Similar to the push rod in the previously described embodiment, the integrated push rod 539 may extend from the inner surface of the poppet 532 along the central axis of the diaphragm assembly 530 through an opening 531 between the side walls 534, accompanied by a proximal flanged upper surface 536, and the integrated push rod 539 may be coupled to the actuator 114 via a motion booster assembly 516, thereby amplifying the movement of the actuator 114 and transmitting it to the integrated push rod 539 via a lever-like mechanism. The integrated push rod 539 may move along the central axis of the diaphragm assembly 530 in response to the movement of the actuator 114, allowing the external sealing surface of the poppet 532 to open and close the flow path through the control valve cavity 110, providing a means for opening and closing the flow path through the control valve cavity 110. The integration of the integrated pushrod 539 may enable a potential improvement in reliability by preventing lateral pushrod movement, and may also enable a simpler, more robust structure by reducing the number of parts, potentially limiting the propagation of errors associated with the combination of individually manufactured parts.

[0032] The motion booster assembly 516 can interface with the integrated push rod 539 and actuator 114 on both sides of the pivot point 517, enabling it to amplify the movement of actuator 114 and transmit it to the integrated push rod 539 via a lever-like mechanism, thereby changing the force applied to the poppet 532 by the integrated push rod 539. For example, if actuator 114 extends or moves downward and a force is applied to the motion booster assembly 516 on the right side of the pivot point 517, the portion of the motion booster assembly 516 on the left side of the pivot point 517 will pivot upward, so an upward force is applied to the integrated push rod 539 via the motion booster assembly 516, causing the integrated push rod 539 to move upward and similarly pull the attached poppet 532 upward.

[0033] The motion booster assembly 516 can receive a spherical projection at the end of an integrated push rod 539 in an upward-facing socket located to the left of the pivot point 517. The diaphragm assembly 530 can act as a spring and exert a restoring force transmitted through the integrated push rod 539 on the upward-facing socket of the motion booster assembly 516 during deformation, enabling the control valve assembly 500 to function with fewer required parts. For example, the diaphragm assembly 530 can bias the outer sealing surface of the poppet 532 toward a normally-closed extended resting state by applying an expansion force, and when compressed from the resting state, it can apply a downward force to the motion booster assembly 516, while the outer sealing surface of the poppet 532 retracts from the extended resting state. The actuator 114 can counteract the force applied to the motion booster assembly 516 by the diaphragm assembly 530 as described above, causing the outer sealing surface of the poppet 532 to retract and open the normally-closed passage through the control valve cavity 110. As a result, the integrated push rod 539 can move along the central axis of the diaphragm assembly 530 in response to the movement of the actuator 114, allowing the external sealing surface of the poppet 532 to open and close the flow path through the control valve cavity 110, providing a means for opening and closing the flow path through the control valve cavity 110.

[0034] The stationary position of the external sealing surface of the poppet 532 may be positioned in a normally closed extended state, thereby obstructing the flow path through the control valve cavity 110 between the control valve cavity inlet port 109 and the control valve cavity outlet port 111, as shown. In some examples, the external sealing surface of the poppet 532 may be fully extended to interface with the control valve cavity inlet port 109, preventing any flow through the control valve cavity 110. The upward tensile force applied to the poppet 532 by the integrated push rod 539 may be increased, for example, by the movement of the actuator 114 transmitted to the integrated push rod 539 via the motion booster assembly 516, thereby retracting the external sealing surface of the poppet 532 and leaving an unobstructed flow path between the control valve cavity inlet port 109 and the control valve cavity outlet port 111. The external sealing surface of the poppet 532 may extend and return to the normally closed resting position when the upward pulling force provided by the integrated pushrod 539 decreases to a normal resting level, such as when the force applied to the motion booster assembly 516 by the actuator 114 decreases as the actuator 114 moves upward or retracts, and the restoring force of the diaphragm assembly 530 allows the external sealing surface of the poppet 532 to extend, returning the flow path through the control valve cavity 110 to its normally closed inhibited state. The gas flow can be regulated by controlling this extension and contraction of the diaphragm assembly 530 via the actuator 114.

[0035] Referring here to Figure 6, a cross-sectional view of an exemplary embodiment of a normally open control valve assembly 600 of a mass flow controller is shown, with a diaphragm assembly 630 having a formed poppet 632 integrated with a clamp block 620. The control valve assembly 600 may be coupled to a mass flow controller base plate 622, which may have a flow path that allows gas to pass from a bypass portion outlet port 608 to a control valve cavity inlet port 609 and flow into the control valve cavity 610 when the flow path through the control valve cavity 610 is in an open, unobstructed state. The gas can then proceed along the flow path through the control valve cavity outlet port 611 and exit the mass flow controller through the mass flow controller outlet port 612.

[0036] The diaphragm assembly 630 comprises an opening 631, a side wall 634 extending downward from the opening 631 and positioned around a central axis, including a plurality of ripples forming a bellows, and a poppet 632 including an inner surface facing the opening 631 and an outer sealing surface facing the control valve cavity inlet port 609. The diaphragm assembly 630 may be configured to expand and contract movably within the control valve cavity 610, thereby enabling control of the gas flow through the passage. The design of the diaphragm assembly 630 may allow for greater deflection with a smaller diameter than conventional sheet metal diaphragm assemblies. The illustrated actuator 114 and motion booster assembly 116 are the same as those in the embodiment of Figure 2. The push rod 618 can extend from the inner surface of the poppet 632 along its central axis through the opening 631, and the push rod 618 can be coupled to the actuator 114 via the motion booster assembly 116, thereby amplifying and transmitting the movement of the actuator 114 to the push rod 618 via a hinge-like mechanism. The actuator 114 and the push rod 618 can interface with the motion booster assembly 116, which has a rounded surface, and the motion booster assembly 116 can pivot along such interface without generating excessive stress. The push rod 618 can move along its central axis in response to the movement of the actuator 114, allowing the external sealing surface of the poppet 632 to open and close the flow path through the control valve cavity 610, providing a means for opening and closing the flow path through the control valve cavity 610.

[0037] The diaphragm assembly 630 may have a flanged top surface that is integrated with the clamp block 620, for example by welding, to form a single component. The integration of the flanged top surface with the clamp block 620 is configured to seal the control valve cavity 610 and control and maintain the pressure in the flow path. Furthermore, the seal provided by the integration of the flanged top surface with the clamp block 620 may allow the push rod 618 and other mass flow controller components to be protected from exposure to the gas in the flow path, potentially preventing corrosion or other gas-related deterioration. Thus, the integration of the flanged top surface with the clamp block 620 may provide a means for sealing the control valve cavity 610 away from the actuator 114 and the motion booster assembly 116. The side wall 634, or bellows, may be coupled between sealing means such as the integrated flanged top surface and clamp block 620 and means for opening and closing the flow path through the control valve cavity 610, such as the external sealing surface of the poppet 632. The poppet 632 may be formed as a component integrated with the side wall 634 of the diaphragm assembly 630 at the end opposite the opening 631. The inner surface of the poppet 632 may include a recess, such as a broad indentation, configured to receive a push rod 618 which may have a rounded end. Such a recess may allow for potentially increased reliability of the mass flow controller by preventing lateral movement of the push rod 618 which may interfere with proper valve closure. However, other embodiments may potentially feature various push rod geometries, such as a push rod with a flat end that can interface directly with the poppet without a recess.

[0038] The diaphragm assembly 630 may be seated within the control valve cavity 610 and within the recess of the clamp block 620, and may be fixed in place by the integration of the clamp block 620 and its flanged upper surface adjacent to the opening 631, and by the upper surface of the clamp block 620. An O-ring, such as a metal O-ring, may be placed between the clamp block 620 and the mass flow controller base plate 622 within the orifice of the mass flow controller base plate 622 adjacent to the side wall 634 of the diaphragm assembly 630. The clamp block 620 may be coupled to the mass flow controller base plate 622, for example, by screws or other fasteners.

[0039] The rotation, or bellows, of the side wall 634 of the diaphragm assembly 630 can be configured to deform along the central axis of the diaphragm assembly 630 and exert a restoring force during deformation. This restoring force can bias the poppet 632 to the normally open resting position, provided it is not disturbed by other forces, such as via the push rod 618. As a result, the diaphragm assembly 630 itself can function as a biasing spring, and the control valve assembly 600 can operate without the additional springs conventionally associated with the control valve. The wall thickness, torsion, and rotation geometry of the side wall 634 can be modified to achieve a specific effective spring constant.

[0040] The resting position of the outer sealing surface of the poppet 632 may be in a normally open, retracted state, thereby the flow path through the control valve cavity 610 between the control valve cavity inlet port 609 and the control valve cavity outlet port 611 is in a normally open, unobstructed state, while the diaphragm assembly 630 is shown in an extended, closed state, which is the resting position that is not open. The push rod 618 can push the poppet 632 into such an extended state, obstructing the flow path between the control valve cavity inlet port 609 and the control valve cavity outlet port 611 to the outer sealing surface of the poppet 632. In some examples, the outer sealing surface of the poppet 632 may be fully extended to interface with the control valve cavity inlet port 609, preventing any flow through the control valve cavity 610. When the force provided by the pushrod 618 decreases to a normal resting level, the outer sealing surface of the poppet 632 can return to its normally open resting position, and the restoring force of the diaphragm assembly 630 causes the outer sealing surface of the poppet 632 to retract, allowing the flow path through the control valve cavity 610 to return to its normally open state. The gas flow can be regulated by the control valve assembly 600, which controls this expansion and contraction of the diaphragm assembly 630 via the actuator 114.

[0041] Referring here to Figure 7, a cross-sectional view of an exemplary embodiment of a normally open control valve assembly 700 of a mass flow controller is shown, with a diaphragm assembly 730 having a separately coupled poppet 732 integrated with a clamp block 720. The control valve assembly 700 may be coupled to a mass flow controller base plate 722, which may have a flow path through which gas can pass from a bypass portion outlet port 708 through an orifice element 713 to the control valve cavity inlet port 709 and enter the control valve cavity 710 when the flow path through the control valve cavity 710 is in an open, unobstructed state. The orifice element 713 may enable better control of specific aspects of the flow to the control valve cavity 710, such as directionality, velocity, and turbulence during operation, by providing a structural geometry that affects the flow. For example, the orifice element 713 may provide a narrower geometry to increase the flow velocity into the control valve cavity 710. The gas then travels along the flow path through the control valve cavity outlet port 711 and can exit the mass flow controller through the mass flow controller outlet port 712.

[0042] The diaphragm assembly 730 may comprise an opening 731, a side wall 734 extending downward from the opening 731 and positioned around a central axis, including a plurality of ripples forming a bellows, and a poppet 732 including an inner surface facing the opening 731 and an outer sealing surface facing the control valve cavity inlet port 709. The diaphragm assembly 730 may be configured to expand and contract movably in part within the control valve cavity 710, thereby enabling control of the gas flow through the passage. The design of the diaphragm assembly 730 may allow for greater deflection with a smaller diameter than conventional sheet metal diaphragm assemblies. The illustrated actuator 114 and motion booster assembly 116 are the same as those in the embodiment of Figure 2. The push rod 718 may extend from the inner surface of the poppet 732 along its central axis through the opening 731, and the push rod 718 may be coupled to the actuator 114 via a motion booster assembly 116, which can amplify and transmit the movement of the actuator 114 to the push rod 718 via a hinge-like mechanism. The actuator 114 and the push rod 718 may interface with the motion booster assembly 116, which has a rounded surface, and the motion booster assembly 116 may pivot along such interface without generating excessive stress. The push rod 718 may move along its central axis in response to the movement of the actuator 114, allowing the external sealing surface of the poppet 732 to open and close the flow path through the control valve cavity 710, providing a means for opening and closing the flow path through the control valve cavity 710.

[0043] The diaphragm assembly 730 may have a flanged top surface that is integrated with a clamp block, such as by welding, to form a single component. The integration of the flanged top surface with the clamp block 720 is configured to seal the control valve cavity 710, allowing for the control and maintenance of pressure within the flow path. Furthermore, the seal provided by the integration of the flanged top surface with the clamp block 720 may allow the push rod 718 and other mass flow controller components to be protected from exposure to gas in the flow path, potentially preventing corrosion or other gas-related deterioration. Thus, the integration of the flanged top surface with the clamp block 720 may provide a means for sealing the control valve cavity 710 away from the actuator 114 and the motion booster assembly 116. The side wall 734, or bellows, may be coupled between sealing means such as the integrated flanged top surface and clamp block 720 and means for opening and closing the flow path through the control valve cavity, such as the external sealing surface of the poppet 732. The poppet 732 may be a separate part, such as a machined part, joined to the side wall 734 at the end opposite the opening 731, for example, by welding. The inner surface of the poppet 732 may include a recess, such as a broad indentation, configured to receive a push rod 718, which may have a rounded end. Such a recess may allow for a potentially increased reliability of the mass flow controller by preventing lateral movement of the push rod 718 that could interfere with proper valve closure. However, other embodiments may potentially feature various push rod geometries, for example, a push rod with a flat end that can interface directly with the poppet without a recess.

[0044] The diaphragm assembly 730 may be seated within the control valve cavity 710 and within the recess of the clamp block 720, and may be fixed in place by the integration of the clamp block 720 with the flanged upper surface adjacent to the opening 731 and by the upper surface of the clamp block 720. An O-ring, such as a metal O-ring, may be placed between the clamp block 720 and the mass flow controller base plate 722 within the orifice of the mass flow controller base plate 722 adjacent to the side wall 734 of the diaphragm assembly 730. The clamp block 720 may be coupled to the mass flow controller base plate 722, for example, by screws or other fasteners.

[0045] The rotation, or bellows, of the side wall 734 of the diaphragm assembly 730 can be configured to deform along the central axis of the diaphragm assembly 730 and exert a restoring force during deformation. This restoring force can bias the poppet 732 to the normally open resting position, provided it is not disturbed by other forces, such as via the push rod 718. As a result, the diaphragm assembly 730 itself can function as a biasing spring, and the control valve assembly 700 can operate without the additional springs conventionally associated with the control valve. The wall thickness, torsion, and rotation geometry of the side wall 734 can be modified to achieve a specific effective spring constant.

[0046] The resting position of the outer sealing surface of the poppet 732 may be in a normally open retracted state, thereby the flow path through the control valve cavity 710 between the control valve cavity inlet port 709 and the control valve cavity outlet port 711 is in a normally open unobstructed state, while the diaphragm assembly 730 is shown in an extended closed state, not in a normally open resting position. The push rod 718 can push the poppet 732 into such an extended state, obstructing the flow path between the control valve cavity inlet port 709 and the control valve cavity outlet port 711 to the outer sealing surface of the poppet 732. In some examples, the outer sealing surface of the poppet 732 may be fully extended to interface with an orifice element 713 located within the control valve cavity inlet port 709, preventing any flow through the control valve cavity 710. The outer sealing surface of the poppet 732 can return to the normally open resting position when the force provided by the push rod 718 decreases to a normal resting level, and the restoring force of the diaphragm assembly 730 can retract the outer sealing surface of the poppet 732, returning the flow path through the control valve cavity 710 to its normally open state. The gas flow can be regulated by the control valve assembly 700, which controls this expansion and contraction of the diaphragm assembly 730 via the actuator 114.

[0047] Referring here to Figure 8A, a cross-sectional view of an exemplary embodiment of a diaphragm assembly 830a having a formed flanged top surface is shown, such as the diaphragm assembly 130 shown in embodiments of Figures 1, 2 and 4. The diaphragm assembly 830a may be substantially cylindrical and may comprise an opening 831a, a side wall 834a extending downward from the opening 831a and arranged around a central axis 840, including a plurality of ripples forming a bellows, and a poppet 832a including an inner surface facing the opening 831a and an outer sealing surface which may include an illustrated flange configured to interact with the gas in the flow path. The diaphragm assembly 830a may be configured to expand and contract movably, for example, with at least a portion of the diaphragm assembly 830a positioned in a control valve cavity along the flow path of a mass flow controller, thereby enabling control of the gas flow through the flow path. The design of the diaphragm assembly 830a may allow for greater deflection with a smaller diameter than conventional sheet metal diaphragm assemblies. The inner surface of the poppet 832a may include a recess 838a, such as a drawn conical notch, configured to receive a push rod, which may have ends with various geometries, such as rounded ends. Such a recess may potentially improve the reliability of the mass flow controller by preventing lateral movement of the push rod that could interfere with proper valve closure. The side wall 834a may surround the push rod received by the recess 838a, allowing the push rod to extend from the inner surface of the poppet 832a along the central axis 840 through an opening 831a that may potentially be coupled to an actuator. The push rod may move along the central axis 840 in response to the movement of the actuator, allowing the external sealing surface of the poppet 832a to open and close a flow path, for example, through a control valve cavity, providing a means for opening and closing the flow path through the control valve cavity.

[0048] The diaphragm assembly 830a may have a laterally extending flanged top surface 836a, which may be configured to seal, for example, a control valve cavity, thereby controlling and maintaining the pressure in the flow path of the mass flow controller. Furthermore, the sealing function provided by the flanged top surface 836a may allow for the protection of mass flow controller components such as actuators, motion booster assemblies, push rods, or biasing springs from exposure to the gas in the flow path, potentially preventing corrosion or other gas-related deterioration. Thus, the flanged top surface 836a may provide a means for sealing the control valve cavity away from the actuator and motion booster assemblies, and the side wall 834a, i.e., bellows, may be coupled between the sealing means such as the flanged top surface 836a and the means for opening and closing the flow path through the control valve cavity, such as the outer sealing surface of the poppet 832a. The illustrated flanged top surface 836a may be formed as a component integrated with the side wall 834a adjacent to the opening 831a, while the illustrated poppet 832a may be a separate component, such as a machined part, joined to the side wall 834a at the end opposite the opening 831a, for example, by welding. The flanged top surface 836a may provide means for securing the diaphragm assembly 830a. For example, the diaphragm assembly 830a may be seated in the control valve cavity of a mass flow controller, and the flanged top surface 836a may be pressed between a clamp block and a mass flow controller base plate to secure the diaphragm assembly 830a in place.

[0049] The rotation, or bellows, of the side wall 834a of the diaphragm assembly 830a can be configured to deform along the central axis 840 of the diaphragm assembly 830a and exert a restoring force during deformation. For example, this restoring force can bias the poppet 832a to its default resting position if not inhibited by other forces, such as through a push rod. As a result, the diaphragm assembly 830a itself can function as a biasing spring within the control valve assembly, enabling operation without additional springs conventionally associated with the control valve. The wall thickness, torsion, and rotation geometry of the side wall 834a can be modified to achieve a specific effective spring constant. The diaphragm assembly 830a may contain a non-brittle material such as metal, which can allow for a greater restoring force during deformation and protect the diaphragm assembly 830a from fracture.

[0050] Referring here to Figure 8B, a cross-sectional view of an exemplary embodiment of a diaphragm assembly 830b having a separately coupled flanged top surface 836b, similar to the diaphragm assembly 330 shown in the embodiment of Figure 3. The diaphragm assembly 830b in Figure 8B is substantially the same as the diaphragm assembly 830a shown in Figure 8A, except for the flanged top surface 836b and the slightly thicker side wall 834b. As in the embodiment of Figure 8A, the diaphragm assembly 830b may be substantially cylindrical and may comprise an opening 831b, a side wall 834b extending downward from the opening 831b and arranged around a central axis 840, including a plurality of ripples forming a bellows, and a poppet 832b including an inner surface facing the opening 831b which may include a recess 838b and an outer sealing surface which may include the illustrated flange and is configured to interact with the gas in the flow path. In contrast to the embodiment of Figure 8A, the flanged top surface 836b and poppet 832b of the diaphragm assembly 830b are separate parts, such as machined parts, joined to the side wall 834b of the diaphragm assembly 830b, for example, by welding. The flanged top surface 836b is positioned close to the opening 831b, and the poppet 832b is positioned at the opposite end of the opening 831b. The resulting flanged top surface 836b has a greater thickness than the flanged top surface 836a formed in the embodiment of Figure 8A. Furthermore, the side wall 834b includes an elongated neck 850 that extends into the flanged top surface 836b.

[0051] The flanged top surfaces 836a and 836b are sealing surfaces, and as a result, the flanged top surfaces 836a and 836b can be sealed with metal O-rings. The greater thickness of the flanged top surface 836b in Figure 8B (in contrast to the thinner flanged top surface 836a in Figure 8A) allows it to handle more force required to seal with metal O-rings without deforming or damaging the flanged top surface 836b. The elongated neck 850 allows the flanged top surface 836b to be welded to the side wall 834b of the diaphragm assembly 830b.

[0052] In some cases, separate, unformed parts such as the flanged top surface 836b and the poppet 832b may allow for greater flexibility in manufacturing with interchangeable and compatible components. For example, an alternative design for the poppet 832b can be manufactured and replaced without changing the manufacturing process for the entire diaphragm assembly 830b, which could potentially reduce manufacturing costs.

[0053] Referring here to Figure 9A, a cross-sectional view of an exemplary embodiment of a diaphragm assembly 930a having an integrated push rod 939a and a formed flanged upper surface 936a is shown, similar to the diaphragm assembly 530 shown in the embodiment of Figure 5. The diaphragm assembly 930a of Figure 9A is substantially the same as the diaphragm assembly 830a shown in Figure 8A, except that it has an integrated push rod 939a and lacks the recess 838a of the embodiment of Figure 8A. As in the embodiment of Figure 8A, the diaphragm assembly 930a may be substantially cylindrical and may comprise an opening 931a, a side wall 934a extending downward from the opening 931a and arranged around a central axis 840, including a plurality of ripples forming a bellows, and a poppet 932a including an inner surface facing the opening 931a and an outer sealing surface which may include an illustrated flange configured to interact with the gas in the flow path.

[0054] In contrast to the embodiment shown in Figure 8A, the diaphragm assembly 930a may have an integrated push rod 939a integrated with the inner surface of the poppet 932a, thereby forming a single part. Similar to the push rod in the previously described embodiment, the integrated push rod 939a may extend from the inner surface of the poppet 932a along the central axis 840 of the diaphragm assembly 930a through an opening 931a between the side walls 934a, accompanied by a nearby flanged upper surface 936a, allowing the integrated push rod 939a to potentially couple with an actuator. The upper end of the integrated push rod 939a may include a spherical projection configured to interface with, for example, a motion booster assembly or actuator of a mass flow controller. The integrated push rod 939a may move along the central axis 840 of the diaphragm assembly 930a in response to the movement of, for example, an actuator, allowing the external sealing surface of the poppet 932a to open and close the flow path through the control valve cavity, providing a means for opening and closing the flow path through the control valve cavity. The integration of the integrated pushrod 939a may enable a potential improvement in reliability by preventing lateral pushrod movement, and may also enable a simpler, more robust structure by reducing the number of parts, potentially limiting the propagation of errors associated with the combination of separately manufactured parts.

[0055] Referring here to Figure 9B, a cross-sectional view of an exemplary embodiment of a diaphragm assembly 930b having an integrated push rod 939b and a separately coupled flanged top surface 936b is shown. The diaphragm assembly 930b in Figure 9B is substantially the same as the diaphragm assembly 930a shown in Figure 9A, except for the flanged top surface 936b and a slightly thicker side wall 934b. As in the embodiment of Figure 9A, the diaphragm assembly 930b may be substantially cylindrical and may comprise an opening 931b, a side wall 934b extending downward from the opening 931b and arranged around a central axis 840, including a plurality of ripples forming a bellows, and a poppet 932b including an inner surface facing the opening 931b and an outer sealing surface which may include an illustrated flange configured to interact with the gas in the flow path. The diaphragm assembly 930b may have an integrated push rod 939b integrated with the inner surface of the poppet 932b, thereby forming a single component with the poppet 932b. In contrast to the embodiment in Figure 9A, the flanged top surface 936b and the poppet 932b are separate parts, such as machined parts, that are joined to the side wall 934b of the diaphragm assembly 930b, for example by welding, along with the integrated push rod 939b of the diaphragm assembly 930b. The flanged top surface 936b is positioned close to the opening 931b, and the poppet 932b is positioned at the opposite end of the opening 931b. The resulting flanged top surface 936b has a greater thickness than the flanged top surface 936a formed in the embodiment in Figure 9A. Consequently, the opening 931b is slightly more elongated compared to the opening 931a in the embodiment in Figure 9A.

[0056] The foregoing description of the disclosed embodiments is provided so that those skilled in the art may construct or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Accordingly, the invention is not intended to be limited to the embodiments shown herein, but rather should be given the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flow path including a control valve cavity having a control valve cavity inlet port and a control valve cavity outlet port, A mass flow meter configured to measure the mass flow rate of gas flowing through the aforementioned flow path, A controller configured to provide actuator control signals in response to a mass flow signal from the mass flow meter, An actuator configured to move in response to the actuator control signal, A diaphragm assembly configured such that at least a portion of it is movable and expandable within the control valve cavity, A push rod extending from the poppet of the diaphragm assembly along the central axis, A motion booster assembly interposed between the actuator and the push rod Equipped with, The motion booster assembly is configured to amplify the movement of the actuator and transmit it to the push rod. The push rod moves along the central axis in response to the movement of the actuator transmitted via the motion booster assembly, and the outer sealing surface of the poppet opens and closes the flow path through the control valve cavity. Mass flow controller.

2. The mass flow controller according to claim 1, wherein the motion booster assembly is configured to amplify the movement of the actuator and transmit it to the push rod via a hinge-like mechanism.

3. The mass flow controller according to claim 1 or 2, wherein the actuator and the push rod are in contact with the motion booster assembly having a rounded surface.

4. The mass flow controller according to claim 3, wherein the motion booster assembly is pivotable at the contact portion with the actuator and the push rod.

5. The mass flow controller according to claim 1 or 2, wherein the motion booster assembly is in contact with the push rod and the actuator on both sides of the pivot point.

6. The mass flow controller according to claim 5, wherein the motion booster assembly amplifies the movement of the actuator via a lever-like mechanism and transmits it to the push rod, thereby changing the force applied to the poppet by the push rod.

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