mass flow controller

Abstract

This invention relates to a mass flow controller (1) for providing a fluid mass flow rate, comprising a valve module (2) and a measuring assembly (3), wherein at least two valve assemblies (72) are provided in the valve module (2) between a supply connector (7) and an outlet connector (113), and the measuring assembly (3) has an inlet connector (43) for connecting to the outlet connector (113) and a working connector (8) for connecting to a fluid consumption device, wherein an extension is provided between the inlet connector (43) and the working connector (8). An extension working channel (42) is provided, in which a flow throttle (201) is provided, and the working channel (42) is equipped with a pressure sensor assembly (61, 62) for measuring the pressure difference at the flow throttle (201), and has a control device (75) electrically connected to the pressure sensor assembly (61, 62) and connected to the valve module (2), and is configured to calculate the fluid mass flow rate in the working channel (42) from the sensor signals of the pressure sensor assembly (61, 62), and to control the valve assembly (72).

Description

Technical Field

[0001] The present invention relates to a mass flow controller for providing a mass flow rate of a fluid. Prior Art

[0002] US Pat. No. 101,656,684 B2 discloses a fluid manipulation device capable of establishing a cable connection even when multiple fluid manipulation devices are arranged adjacently. The fluid manipulation device includes a fluid manipulation unit for manipulating the flow rate or pressure of a fluid, a circuit board for transmitting and receiving signals to the fluid manipulation unit, a housing for accommodating the fluid manipulation unit and the circuit board, and a device-side connector disposed between the circuit board and a cable electrically connected to the circuit board. The fluid manipulation device further includes a connecting plate designed to be mounted on the device-side connector. The connecting plate is fixed to the circuit board, with at least a portion of the connecting plate in surface contact with the circuit board, or the circuit board overlaps at a distance therebetween. Summary of the Invention

[0003] The object of the present invention is to provide a mass flow controller with a compact structure. With respect to the mass flow controller of the type described at the beginning for providing a fluid mass flow rate, the purpose of the present invention is achieved by the following features: the mass flow controller includes a valve module and a measuring combination, the valve module has a supply connector for connecting to a fluid source, and an outlet connector for providing a fluid mass flow rate to the measuring combination, and at least two valve combinations are provided between the supply connector and the outlet connector in the valve module, each responsible for proportionally influencing the fluid mass flow rate, and the measuring combination has an inlet connector for connecting to the valve module outlet connector, and a working connector for connecting to a fluid consumption device, and a working channel extends between the inlet connector and the working connector, in which a flow throttling is provided, and a pressure sensor combination is configured for the working channel to measure the pressure difference before and after the throttling, and a control device electrically connected to the pressure sensor combination and connected to the valve module, and the control device is designed to detect the fluid mass flow rate in the working channel by means of the signal of the pressure sensor combination, and to control the valve combination so that it maintains the required value of the fluid mass flow rate.

[0004] The purpose of the valve assembly in a valve module is to influence a fluid flow rate provided by a fluid source, such as a compressed air source or a process gas source, at a supply connection of the valve module so that a desired fluid mass flow rate is provided at a working connection of a mass flow controller. The valve assembly of the valve module is preferably designed to throttle a maximum fluid mass flow rate provided by the fluid source to a desired fluid mass flow rate at the working connection based on a throttling effect. This throttling effect is generated by at least two valve assemblies provided in the valve module. Particularly preferably, each valve assembly of the valve module can individually and freely adjust this throttling effect.

[0005] Multiple, particularly at least two, valve assemblies are each electrically connected to a control device and can be switched between a closed position and an open position in response to an electrical control signal from the control device. Each valve assembly functions to influence a portion of the fluid mass flow in the working channel. Preferably, each valve assembly influences the fluid mass flow by the same amount. This can be achieved by designing the valve assemblies of the valve module to have identical structures and supplying control signals from the control device in the same manner. Particularly preferably, each valve assembly is individually parameterized in the control device to ensure that the same maximum valve cross-section is always released for each valve assembly.

[0006] The use of multiple valve assemblies in a valve module particularly allows for a particularly compact design of the valve module and its mass flow controller in one of three Cartesian spatial directions, which may represent, for example, the width, length, and height of the valve module. This compact design results from the fact that each valve assembly has a relatively small dimension in one spatial direction and that the valve assemblies are arranged adjacent to each other in another spatial direction. For example, the valve assemblies may be of a square design with a circular, rectangular, or square cross-section and arranged adjacent to each other in the valve module in a spatial direction perpendicular to the longest side of the valve module.

[0007] The fluid mass flow rate originates from the supply connector of the valve module, passes through at least two valve assemblies within the valve module, and flows out of an outlet connector of the valve module before being directly supplied to the inlet connector of a measuring assembly. A mechanical separation can be implemented between the valve module and the measuring assembly, and a seal can be provided between the outlet connector and the inlet connector. Alternatively, the valve module and the measuring assembly can belong to the same structural group.

[0008] In addition to the inlet connector, the measuring assembly also includes a working connector for connecting a fluid consuming device. The fluid consuming device may be, for example, a fluid actuator or a reaction tank, which needs to be supplied with a preset fluid mass flow rate when executing a production process.

[0009] A working channel, also referred to as a measuring section, extends through the measuring assembly between the inlet connector and the working connector. A flow restriction is provided in this working channel, designed to generate a pressure drop between the inlet connector and the working connector that depends on the fluid mass flow rate. This pressure difference allows for measurement, and the mass flow rate of the fluid flowing through the working channel can be calculated from the pressure difference using an appropriate calculation model.

[0010] Using a flow restriction can generate a significant pressure differential across the flow restriction between a first upstream measuring point and a second downstream measuring point in the working channel.

[0011] To measure the pressure drop across the flow restriction, a pressure sensor assembly is assigned to the working channel and electrically connected to a control device. The pressure sensor assembly detects the pressure differential across the flow restriction. To this end, a pressure differential signal generated directly by the pressure sensor assembly can be provided to the control device, or multiple discrete pressure signals can be provided to the control device for further processing.

[0012] The purpose of the control device is to calculate a pressure differential from the sensor signals of the combined pressure sensors and, using a mathematical model, to determine the current state of the fluid mass flow in the working channel from the pressure differential. The calculated fluid mass flow is then compared with a predetermined (expected) fluid mass flow in the control device. If there is a difference between the calculated fluid mass flow and the predetermined fluid mass flow, one or more control signals are generated for the valve module to minimize the difference. The control signal provided by the control device is converted in the valve module, causing the throttling effect of the valve module to produce the required fluid mass flow. A closed control loop ensures that the mass flow controller provides the fluid mass flow to the working connector.

[0013] Further improvements of the invention are described in the appendix to the patent claims.

[0014] It is meaningful that the fluid throttling is designed as a turbulent throttling, which includes at least two flow-guiding elements, selected from the group of an inlet plate with at least one inlet hole, a throttling plate with at least one throttling hole, and an outflow plate with at least one outflow hole, and the two are arranged in the working channel to keep a distance from each other, and the at least one inlet hole, the at least one throttling hole, and the at least one outflow hole are offset from each other in a spatial direction transverse to the center axis of the working channel.

[0015] A turbulent flow throttle can accurately predict the pressure drop of the mass flow of the fluid flowing through the working channel and can accurately measure the pressure difference. In addition, compared with other throttling elements, especially laminar flow elements, the turbulent flow throttle has a simple and cost-effective structure.

[0016] The basis of the turbulence throttle function is that the fluid mass flow is diverted multiple times, in particular at least twice, through the turbulence throttle and thus undergoes multiple changes of flow direction, so that a desired significant pressure drop can be achieved across the turbulence throttle.

[0017] To this end, at least two, preferably three, flow guide elements are provided on the flow throttle, each of which is penetrated by one or more grooves. The grooves of the flow guide elements are arranged adjacent to each other, and the flow guide elements are designed and arranged in a projection plane transverse to the main flow direction of the fluid mass flow, in particular transverse to a central axis of the outflow channel, so that the projection lines of the grooves of adjacent flow guide elements do not overlap.

[0018] Depending on the design of the flow guide element and the fluid pressure applied at the supply connection, the fluid in the flow guide element (inlet plate and / or throttle plate and / or outlet plate) flows through the grooves (inlet orifice and / or throttle orifice and / or outlet orifice) at a speed below the speed of sound (subcritical flow regime) or above the speed of sound (supercritical flow regime). Turbine throttles operating in a subcritical flow regime require more space. In contrast, turbine throttles operating in a supercritical flow regime require a more compact design. Depending on the specific application of the mass flow controller, the turbine throttle is designed to operate in either a subcritical or supercritical flow regime throughout the specified mass flow control range.

[0019] The design of each flow-throttling device maintains the same throttling characteristics regardless of flow direction. This allows the mass flow controller's supply connector to be connected to a source providing both pressurized fluid and a low-pressure fluid source. However, sometimes the valve module may need to be modified to accommodate the fluid source.

[0020] Preferably, the at least one inlet, at least one throttle, and at least one outlet are offset from each other in a non-overlapping manner along their mid-axis in a transverse projection plane. This ensures that each gas molecule in the fluid flow is forced to undergo multiple changes in flow direction, which are necessary to ensure high accuracy in differential pressure measurement. Due to the offset arrangement between the at least one inlet and at least one throttle, and between the at least one throttle and at least one outlet, no gas molecule can pass through the turbulent flow restriction on streamlines parallel to the mid-axis of the pair of working channels.

[0021] Advantageously, the inflow plate has a plurality of inflow holes at a radial distance from the center axis, and / or the throttle hole of the throttle plate is coaxial with the center axis, and / or the outflow plate has a plurality of outflow holes at a radial distance from the center axis.

[0022] In another embodiment of the present invention, the combined cross-section of the inflow holes is equal to or greater than the cross-section of the throttle holes, and / or the cross-section of the throttle holes is equal to or greater than the combined cross-section of the outflow holes. The combined cross-section refers to the cross-section resulting from the sum of all cross-sections of the inflow holes or outflow holes, and is related to the cross-section of the intercepting hole, preferably a single cross-section. As long as the combined cross-section of the inflow holes and / or the outflow holes is equal to the cross-section of the intercepting hole, then under the additional condition that the distance between the inflow plate and the intercepting plate is equal to the distance between the outflow plate and the intercepting plate, the throttling effect of the throttling flow is unaffected by flow direction. If this flow direction independence is not necessary, the combined cross-section of the inflow holes can be greater than the cross-section of the intercepting hole. Alternatively or additionally, the combined cross-section of the outflow holes can be smaller than the cross-section of the throttling hole. This can enhance the throttling effect of the throttling flow, thereby achieving an increased pressure difference at the same fluid flow rate compared to a throttling flow independent of flow direction.

[0023] In another embodiment of the present invention, the throttle plate is designed as a disk. A throttled hole extends from the front circular surface to the rear circular surface, and a front collar extends axially from the front circular surface and is designed to abut against the inlet plate plane, and / or a rear collar extends axially from the rear circular surface and is designed to abut against the outlet plate plane. Thus, in addition to its throttling function, which is determined by the throttle hole and its arrangement relative to the inlet hole of the inlet plate and / or the outlet hole of the outlet plate, the throttle plate also has a function of ensuring a predetermined distance between the inlet plate and / or the outlet plate. To this end, the throttle plate comprises a disk-shaped base body, which can also be described as having a cylindrical cross-section, with a central throttle hole. A front collar can extend axially from a front circular surface of the base body and has an end face facing away from the base body, for abutting against the inlet plate. A rear collar can extend axially from a rear circular surface of the base body and has an end face facing away from the base body, for abutting against the outlet plate. The inner diameter of the front collar and / or the inner diameter of the rear collar are preferably selected so that there is no concern that the fluid flow rate is affected between the inlet plate and the throttle plate and / or between the throttle plate and the outlet plate.

[0024] Advantageously, all inflow holes formed on the inflow plate have the same diameter at the same angular interval and the same radial distance from the center axis, and / or all outflow holes formed on the outflow plate have the same diameter at the same angular interval and the same radial distance from the center axis. This ensures that the inflow and / or outflow plates symmetrically partition the fluid flow provided at the supply connection relative to the center axis of the working channel, resulting in favorable flow behavior in the throttling process. Compared to an asymmetrical partitioning of the fluid flow provided at the supply connection, differential pressure measurement is more stable.

[0025] Preferably, an axial extension of the throttle opening along the center axis corresponds to 2 to 10 times an axial extension of the inlet opening and / or corresponds to 2 to 10 times an axial extension of the outlet opening.

[0026] Advantageously, the flow throttle comprises an inlet plate, a throttle plate, and an outlet plate, which are disposed within a throttle sleeve. This forms an independent structural group that can be manufactured, assembled, and tested independently without involving other mass flow controller components, providing advantages in the mass flow controller manufacturing process.

[0027] In another embodiment of the present invention, the valve module comprises a plurality of valve boxes with mutually parallel extension axes, each housing a valve assembly. The inlet of the valve box is adjacent to the output interface connector, while the outlet connector opens radially into the working channel. The starting point here is that each valve assembly has its own housing and can be tested for functionality before being assembled into the respective valve box. Furthermore, it is envisaged that each valve assembly seals off the respective valve box in the inlet region, so that, for example, all valve boxes can be pressurized together by a pressure fluid supplied from the supply connector. Preferably, the front end face of the valve assembly protruding from the valve box has one or more outlets, through which the fluid flow released by each valve assembly flows partially toward the outlet connector. Furthermore, the outlet connector opens radially into the working channel, which is preferably designed as a cylindrical bore. This ensures that the fluid flow is already diverted during the transition from the valve module to the transducer assembly.

[0028] Advantageously, each valve assembly has at least one valve channel extending between a supply connection and an outlet connection, wherein a valve seat and a piezoelectric bender are disposed. The piezoelectric bender carries a sealing element that closes or opens the valve seat depending on the functional position of the piezoelectric bender. For example, the valve seat is formed in the inner wall of the valve channel and serves as an opening for a connecting hole, which is in fluid communication with the outlet ports of the valve assembly. The piezoelectric bender, provided in the valve channel, together with the sealing element mounted thereon, functions to change the distance between the sealing element and the valve seat through a shape change, particularly a deflection change, thereby selectively partially or completely opening or closing the valve seat. For example, the piezoelectric bender is implemented as a combination of a metal strip and a piezoelectric layer mounted thereon. If the voltage applied to the piezoelectric layer changes, the expansion of the piezoelectric layer changes. This causes the piezoelectric bender to produce the desired shape change, particularly a deflection change. The valve assembly is preferably a proportional valve having a freely selectable valve cross section that can be set by an appropriate control voltage.

[0029] Particularly preferably, a first and a second valve seat are provided in the valve channel, and each valve seat is equipped with a sealing element comprising a piezoelectric bender, so that the valve assembly has a dual valve function. This dual valve function is preferably used in that the two piezoelectric benders are actuated by an actuation device, and when necessary, the piezoelectric benders are actuated individually to simultaneously open the same orifice cross section of the valve seats.

[0030] Preferably, the pressure sensor assembly includes a pressure sensor, particularly a first absolute pressure sensor, connected to the working channel upstream of the spoiler restriction. The pressure sensor assembly also includes a second absolute pressure sensor connected to the working channel downstream of the spoiler restriction. The sensor signals can be interpreted to calculate the pressure drop across the spoiler restriction. If both pressure sensors are designed as relative pressure sensors, an additional absolute pressure sensor is provided as an ambient pressure sensor to determine the pressure level in the working channel. Preferably, the first pressure sensor is designed as a first absolute pressure sensor and the second pressure sensor is designed as a second absolute pressure sensor. In this case, the ambient pressure sensor is not required.

[0031] In addition, the absolute pressure level of the fluid mass flow in the working channel can also be determined from the sensor signal. The control device can use this information to calculate the current fluid mass flow in the working channel.

[0032] Advantageously, the pressure sensor assembly includes an absolute pressure sensor connected to the working channel upstream of the turbulence restriction. The pressure sensor also includes a differential pressure sensor connected to a first differential pressure measurement point located in the working channel upstream of the turbulence restriction and to a second differential pressure measurement point located in the working channel downstream of the turbulence restriction. This pressure sensor assembly is less expensive than a pressure sensor assembly comprising two absolute pressure sensors and is therefore particularly suitable for applications in price-sensitive mass flow controllers.

[0033] Advantageously, the working channel has a rest zone designed as a blind hole in a spatial direction opposite to the main flow direction of the fluid flow and parallel to the central axis. In this rest zone, there is virtually no fluid flow. Placing the first absolute pressure sensor in this rest zone ensures at least a substantially static, or even completely static, pressure. This improves the accuracy of differential pressure measurement across the flow restriction.

[0034] Advantageously, the control device provides a connection point for power input and communication with an AC network. The AC network consists of the following protocols: Modbus, IO Link, Ethernet (EtherCAT), Profibus, DeviceNet, Ethernet-IP, and Profitnet. This allows for both power supply to the mass flow controller and communication with other members of the AC network. Optionally, communication with a cloud database is also possible.

[0035] An advantageous embodiment of the present invention is shown in the drawings, which show: Simple diagram description

[0036] The present invention will be further described below with reference to the accompanying drawings, which show Figure 1 is a stereogram of a mass flow controller. Figure 2 is an exploded view of the central component of the mass flow controller in Figure 1. FIG3 is a planar cross-sectional view of a mass flow controller in FIG1 , FIG4 is a schematic diagram of a mass flow controller designed as a throttling flow controller, which has an inlet plate, a throttling plate, and an outlet plate. Figure 5 is a top view of one of the inflow plates in Figure 1, and Figure 6 is a top view of the throttle plate in Figure 1, FIG7 is a detailed view of a working channel of a mass flow controller equipped with an absolute pressure sensor and a differential pressure sensor. Implementation Method

[0037] A mass flow controller 1 shown in FIG1 is designed as an independent functional component for use in a fluid system (not shown). The fluid system may be, for example, a process gas supply device used in a product manufacturing process. For example, the mass flow controller 1 is used to deliver a predetermined mass flow of a process gas, such as nitrogen, into a workspace (not shown) to process the product according to predetermined process specifications.

[0038] To perform this task, the mass flow controller 1 must be connected to a fluid source (not shown) and a fluid consumer (not shown). Furthermore, the mass flow controller 1 requires electrical energy and, if necessary, a control or AC signal, which indicates the mass flow rate of the fluid to be provided by the mass flow controller 1.

[0039] To connect the mass flow controller 1 to a fluid source (not shown), a supply connector 7 is provided on a front side 21 of the mass flow controller 1, serving as a connector for connecting to a fluid line (not shown). Furthermore, to connect the mass flow controller 1 to a consumer (not shown), a working connector 8 is provided on a rear side 22 opposite the front side 21 of the mass flow controller 1, serving as a connector for connecting to a fluid line (not shown). As will be described in detail below, a fluid mass flow, which may originate from a fluid source (not shown), is directed by the mass flow controller 1 to the working connector 8. The configuration is such that the fluid mass flow is affected within the mass flow controller 1 so that a fluid mass flow rate that meets a predetermined setpoint value is provided at the working connector 8.

[0040] For example, an assembly plate 31 is fixed to the bottom side 24 of the mass flow controller 1 to facilitate assembly of the mass flow controller 1 on a machine platform (not shown in detail).

[0041] FIG1 also shows that the mass flow controller 1 has, purely by way of example, an electrical interface 4 on its top side 23, designed as a 9-pin D-Sub connector. External electrical energy can be supplied to the mass flow controller 1 via interface 4. Furthermore, electrical interface 4 can be used to communicate between the mass flow controller 1 and a higher-level controller (not shown).

[0042] On the upper side 23 near the electrical interface 4, purely by way of example, a first status display 5 and a second status display 6 are provided, which can be used to optically display status information of the mass flow controller 1 and can be designed as light-emitting diodes, for example.

[0043] A selection switch 10 is provided on the right side 26 of the mass flow controller 1. Purely for example, it can be designed as a DIP switch combination. By selecting different switch positions, the mass flow controller 1 configuration suitable for the user can be set.

[0044] The exploded perspective view of Figure 2 shows the main functional components of the mass flow controller 1 in Figure 1. The main functional components that need to be understood are: the valve module 2 and the measurement assembly 3, which includes a channel plate 11 and a sensor plate 12.

[0045] Purely by way of example, the channel plate 11 is made of a metal material, in particular aluminum, or of a plastic, and includes a supply channel 41, which is visible in FIG. 3 , and a working channel 42, which is also visible in FIG. Furthermore, the channel plate 11 has an inlet connection 43, which is visible in the perspective view of FIG. 2 , on one upper side 52 , from which an inlet channel 44, which is visible in FIG. 3 , extends and opens into the working channel 42 . For example, the channel plate 11 is designed in a cuboid shape, with the supply connection 7 and the working connection 8 being provided on opposite end faces, namely, the front side 21 and the rear side 22 of the mass flow controller 1 , respectively.

[0046] On a left side 51 of the channel plate 11, which is preferably flat, are two sensor holes 57 and 58 (visible in FIG3 ), each of which opens into the working channel 42 . Furthermore, screw holes, not visible, are provided on the left side 51 to allow pressure sensors 61 and 62 to be securely fastened to the channel plate 11 in a sealed manner. Pressure sensors 61 and 62 form a pressure sensor assembly, located on the upper side of the sensor plate 12 facing the left side 51 and secured to the left side 51 of the channel plate 11 by fixing screws 63 extending through the sensor plate 12. Purely by way of example, the sensor plate 12 includes an electronic circuit (not shown in detail) for generating pressure signals from the pressure sensors 61 and 62. Furthermore, the sensor plate 12 is electrically connected to the control board 75 by means (not shown), such as a cable connection or a flexible conductive assembly, to provide the sensor signals from the pressure sensors 61 and 62 to the electronic control circuitry of the control board 75. For example, it can be determined that the electronic control circuit on the control board 75 also includes a controller that controls the valve assembly 72 provided in the valve module 2 according to the sensor signals of the pressure sensors 61 and 62.

[0047] The valve module 2 is arranged opposite the upper side 52 of the channel plate 11, and includes a valve housing 71 and multiple valve assemblies 72 in the valve housing 71, a collecting plate 73, a plate retainer 74, a control plate 75, an upper sealing element 76, and a lower sealing element 77.

[0048] The valve housing 71 has a cuboidal shape, with a left screw guide 80 and a right screw guide 81 provided on opposite narrow sides 78 and 79 of the valve housing 71. A set screw 82 penetrates the two screw guides 80 and 81, securing the valve housing 71 and the collecting plate 73 to the channel plate 11. Two sealing elements 76 and 77 are used to provide a seal between the valve housing 71, the collecting plate 73, and the channel plate 11.

[0049] Purely by way of example, it can be provided that the valve housing 71 has a width extension 83 and a height extension 84 which corresponds essentially to the width extension 83 , while a depth extension 85 of the valve housing 71 is only a small fraction of the width extension 83 , for example 20 percent.

[0050] Starting from a bottom side 86 of the valve housing 71, five valve boxes 88, which can be seen in FIG. 3 , extend in a height direction 84 , purely by way of example. Each valve box 88 accommodates, for example, a valve assembly 72 of a snap-on design, which can be inserted into the valve box 88 via an access opening 90 in each valve box 88 , as will be explained further below with reference to FIG. 3 .

[0051] In an embodiment of the mass flow controller 1 not shown, if all the valve assemblies 72 shown in Figures 2 and 3 are not needed, it can be configured such that no valve assembly 72 is provided in one or more valve boxes 88, but only a position holder is provided.

[0052] A plate holder 74 is provided opposite the upper side 87 of the valve housing 71 for accommodating a control plate 75 .

[0053] Control board 75 is constructed as a printed circuit board (PCB) and carries electrical and electronic components (not described in detail) that constitute the control mechanism of mass flow controller 1. For example, in addition to passive electrical components (not shown), such as resistors and capacitors, control board 75 also includes one or more microcontrollers or microprocessors to perform fluid mass flow control, as described further below.

[0054] Since each valve assembly 72, purely by way of example, has two piezoelectric benders 101, which will be described further below, the control board 75 is additionally equipped with a high-voltage component (not shown) that is configured to supply a respective high voltage, particularly a DC voltage in the range of 250 to 500 volts, to each piezoelectric bender 101 of each valve assembly 72. Preferably, all piezoelectric benders 101 of all valve assemblies 72 are controlled by the control device on the control board 75 so that each valve assembly 72 passes a substantially equal proportion of the fluid mass flow rate to the working connection 8. Alternatively, some or all valve assemblies 72 may be equipped with only one piezoelectric bender 101.

[0055] In a simplified configuration of the mass flow controller 1 (not shown), one valve combination has two piezoelectric bender(s), or two valve combinations each have one piezoelectric bender, so that at least one dual valve function is always available.

[0056] As can be seen from FIG. 3 , the piezoelectric bender 101 of the valve assembly 72 passes through the contact pin 105 of the plate holder 74 and is electrically connected to the control board 75 .

[0057] As can also be seen in FIG3 , each valve assembly 72 has a valve channel 102 formed within the cartridge housing 108 of each valve assembly 72, which is visible in FIG2 and 3 . The valve channel 102 of each valve assembly 72 is in fluid communication with a feeder channel 89 of the valve housing 71 , which in turn is connected to the supply channel 41 via a branch channel 53 in the channel plate 11 . Consequently, all valve channels 102 of the valve assembly 72 are pressurized in the same manner with a uniform fluid pressure supplied by the supply connection 7 .

[0058] As shown in FIG3 , two piezobenders 101 are arranged in mirror-image fashion within each cartridge housing 108. Furthermore, the piezobenders 101 are pressed against supporting blades (not shown) within the valve channel 102 by leaf springs 106, also located within the valve channel 102. These supporting blades are adapted for the strip-shaped piezobenders 101, so that when a high voltage is applied to the associated contact pins 105, the piezobenders 101 undergo a bending change. This causes the sealing elements 103 on the facing surfaces of the piezobenders 101 of each valve assembly 72 to be lifted by a valve seat 104 located opposite, as can be seen in the detailed view of FIG3 . It should be noted that, due to the cross-sectional view, only the sealing element 103 of the right-hand piezobender 101 is visible. The same applies to the valve seat 104, which also shows only the right-hand piezobender 101.

[0059] An outlet channel (not shown in detail) extends from each valve seat 104 within the cartridge housing 108. Portions of the fluid mass flow passing through the valve seat 104 can be discharged from the cartridge housing via the outlet channel. An outlet flange 111, visible in FIG. 2 , projects from the collecting plate 73, which is essentially a plane-parallel plate, toward each valve assembly 72 and is sealed to the outlet channel. As can be seen in the cross-sectional view of FIG. 3 , the collecting plate 73 has a square recess 113 on its bottom side 114, forming a collection chamber for a portion of the fluid mass flow provided by each valve assembly 72 via the outlet channel and associated outlet flange 111.

[0060] Beginning at this groove 113, which can also be referred to as the outlet connection of the valve module 2, the fluid mass flow enters the inlet connection 43 of the channel plate 11 and is directed from there into the inlet channel 44. The inlet channel 44 has an inlet channel axis 46, which is transverse to a central axis 45 of the working channel 42 and radially enters the inlet channel 44. Because the working channel 42 extends straight along the central axis 45 to the working connection 8, the fluid mass flow, upon exiting the inlet channel 44, makes a right-angle turn about the central axis 45 and can flow out from there to the working connection 8. This symbolically defines a main flow direction within the working channel 42, parallel to the central axis 45.

[0061] For example, the working channel 42 is configured to extend along the central axis 45, past the inlet channel 44, in the direction opposite to the main flow direction 47. This section of the working channel 42 is formed as a blind hole, referred to as the rest zone 48. Due to the aforementioned reversal of the fluid mass flow rate, starting from the inlet connection 43 and redirected back to the main flow direction 47 within the working channel 42, the fluid pressure can be detected in the rest zone 48. In this rest zone, the dynamic component of the fluid pressure is minimal or even absent, leaving the primary or even entirely static pressure. Therefore, in the rest zone 48, a first sensor hole 57 is provided in the working channel 42 transversely to the central axis 45, into which a first pressure sensor 61 on the control panel 12 extends. A second sensor hole 58 is also provided in the working channel 42 transversely to the central axis 45. In FIG. 3 , the second sensor hole 58 is obscured by the turbulence restriction 201, which will be described further below, and is therefore indicated only by dashed lines. The second sensor 62 extends into the second sensor hole 58 , and the second sensor 62 is also provided on the control board 12 .

[0062] In order to reliably and accurately measure the pressure difference in the working channel 42, the working channel 42 is provided, purely by way of example, with a flow restriction designed as a turbulence restriction 201, which extends completely over the cross section of the working channel 42 and is arranged between the inlet channel 44 and the working connection 8.

[0063] The throttle valve 201, shown in detail in FIG4 , is constructed as a standalone component that can be installed and functionally tested independently of the other components of the mass flow controller. The throttle valve 201 comprises, purely by way of example, a tubular throttle sleeve 203 that is rotationally symmetrical about a central axis 202 and extends along the central axis 202.

[0064] An outer surface 204 of the throttle sleeve 203 , purely by way of example, comprises three adjacent sections along the central axis 202 , namely a first guide section 205 , a sealing section 206 , and a second guide section 207 .

[0065] The first guide section 205 has a first outer diameter 231 that substantially corresponds to an inner diameter of the first throttle section 49 for accommodating the first guide section 205. For example, the first guide section 205 and the first throttle section 49 may have matching external and internal threads, allowing the flow-turbulating throttle 210 to be screwed into the working channel 42.

[0066] The sealing section 206 between the first guide section 205 and the second guide section 207 has an outer diameter 233 smaller than the two guide sections 205 and 207. When the throttle valve 201 is assembled with the throttle section 49 of the working channel 42, it forms a first annular channel 54 with the throttle section 49. A sealing ring 227 is provided within the throttle section 49 to ensure that the throttle sleeve 203 seals against the throttle section 49. Furthermore, the second guide section 207 has an outer diameter 232 similar to or identical to that of the first guide section 205. Because the working channel 42 has a second throttle section 50 adjacent to the throttle section 49 in the main flow direction 47, and having a larger outer diameter, a second annular channel 55 is formed by the throttle valve 201 and the working channel 42. This second annular channel 55 is limited by a radially outwardly projecting collar 228 formed on the end side of the throttle sleeve 203. The second annular channel 55 is similar to the rest zone 48 in terms of fluid technology and is arranged on the other side of the main flow of the fluid mass flow. The second pressure sensor 62 is arranged in this second annular channel 55.

[0067] Purely by way of example, the groove 208 of the throttle sleeve 203, which is rotationally symmetrical about the central axis 202, can be divided into an inlet section 209, a retaining section 210, and an outlet section 211. The inlet section 209 and the outlet section 211 have a larger diameter than the retaining section 210. Purely by way of example, the inlet section 209 and the outlet section 211 each expand slightly conically from the retaining section 210 to an inlet 212 and an outlet 213.

[0068] A plurality of flow-guiding elements are provided in the inlet section 209 to produce the desired turbulence-throttling function for a gaseous fluid as it flows through the turbulence-throttling device 201. Starting from the inlet opening 212, the inlet section 209 is provided with an inlet plate 214, a throttle plate 215 directly adjacent thereto axially along the center axis 202, and an outlet plate 216 directly adjacent to the throttle plate 215 axially along the center axis 202.

[0069] As shown in FIG5 , the inlet plate 214 is circular, designed as a plane-parallel plate, and has a plurality of inlet holes 217. For example, the inlet holes are arranged with equal angular components on a common partial circle 220. For example, the inlet plate 214 can be made of a metal plate, with the inlet holes 217 formed by a laser cutting process or an etching process. Alternatively, the inlet plate can be made of a plastic material, particularly by a plastic injection molding process.

[0070] Preferably, the inflow plate 214 and the outflow plate 216 are constructed identically.

[0071] Compared to the inlet plate 214 and the outlet plate 216, the throttle plate 215 has a significantly greater axial extension along the central axis 202. Functionally, the throttle plate 215 can be divided into a throttle disc 221 and a leading distance ring 222 and a trailing distance ring 223. The throttle disc 221 is circular and has an unnumbered outer diameter that is slightly smaller than the inner diameter of the inlet section 209, also unnumbered. The throttle disc 221 has a throttle orifice 218 coaxial with the outer diameter of the throttle disc 221. Purely for example, the throttle orifice 218 is circular. As shown in FIG. 4 , the throttle disc 221 has an axial extension along the central axis 202 that is approximately seven times the axial extension of the inlet plate 214 and the outlet plate 216. On opposite axial end surfaces 224 and 225, annular distance rings 222 and 223 protrude from the throttle disc 221, serving as axial distance maintainers between the inlet plate 214 and the outlet plate 216. Distance rings 222 and 223 each have an unlabeled inner diameter selected to ensure that the inlet opening 217 of the inlet plate 214 and the outlet opening 219 of the outlet plate 216 are not obstructed. Distance rings 222 and 223 are designed solely for maintaining distance between the inlet and outlet plates 214 and 216, and have no significant effect on the throttling function of the turbulent flow throttle 201, described further below.

[0072] The inner diameter of the retaining section 210 is slightly smaller than the inner diameter of the lower structural group consisting of the inlet plate 214, the throttle plate 215, and the outlet plate 216. The purpose of the retaining section 210 is only to axially support this lower structural group, and has no significant effect on the throttling effect of the turbulent throttling 201 further described below.

[0073] The outflow section 211 has an axial extension along the middle axis that is basically the same as that of the inflow section 209, and its function is to stabilize the fluid flow after it passes through the aforementioned guide elements (inflow plate 214, throttle plate 215, outflow plate 216).

[0074] In addition, a radial hole 226 is formed in the outflow section 211 to ensure fluid communication between the outflow section 211 and the aforementioned second annular channel 55, and to allow detection of the fluid pressure prevailing in the outflow section 211 for the second pressure sensor 62 to detect pressure.

[0075] As shown in Figure 5, the projection 227 of the throttle hole 218 onto the inlet plate 214 does not overlap with the inlet hole 217. This ensures that a fluid (particularly a compressed air flow or a process gas flow) undergoes multiple changes in flow direction as it flows through the turbulence throttle 201. This produces the desired turbulence in the turbulence throttle 201. The advantage of this type of turbulence is that the streamlined design of the turbulence throttle 201 allows for differential pressure measurement. The pressure value upstream or before the turbulence throttle 201, particularly in the area of the inlet 212, can differ from the pressure value downstream or after the turbulence throttle 201 (particularly in the radial holes 226). This allows for precise differential pressure measurement. This differential pressure measurement allows for highly accurate inference of the fluid mass flow rate through the turbulence throttle 201.

[0076] In principle, the mass flow controller 1 is used in a fluid consuming device to provide a fluid mass flow rate. The mass flow controller 1 can also be used as a pressure controller.

[0077] FIG7 shows a cross-sectional view of the channel plate 11 and the working channel 42 therein. The only difference from FIG3 is that, instead of an absolute pressure sensor 62, a differential pressure sensor 66 is used to measure differential pressure within the mass flow controller 1. To this end, the differential pressure sensor 66 has a first measuring point 67 located directly before the throttle 201 for pressure detection. Furthermore, the differential pressure sensor 66 has a second measuring point 68 for pressure detection within the second annular channel 55. The detection method of the first pressure sensor 61 is the same as that in the resting zone 48 in FIG3 . Alternatively, unlike FIG7 , the first measuring point 67 can also be located within the resting zone 48.

[0078] 1:Mass flow controller 2: Valve module 3: Measurement combination 4: Interface 5: First status display 6: Second status display 7: Supply connector 8: Working joint 10: Selector switch 11: Channel plate 12:Sensor board 21:Front 22: Back 23: Upper side 24: bottom side 26: Right side 31:Assembly board 41: Supply Channel 42: Working channel 43: Channel plate inlet connector 44: Channel plate inlet channel 45: Middle axis 46: Inlet channel axis 47: Main flow direction 48: Resting Area 49: Throttling section 50: throttling section 51: Left side of channel plate 52: Upper side 53: Branch channel 54: First Ring Channel 55: Second Ring Channel 57:Sensor hole 58:Sensor hole 61: Pressure sensor 62: Pressure sensor 63:Fixing screw 66: Differential pressure sensor 67: First measurement point 68: Second measurement point 71: Valve housing 72: Valve combination 73: Collection Plate 74: Plate holder 75: Control Panel 76: Upper sealing element 77: Lower sealing element 78: narrow side of valve housing 79: narrow side of valve housing 80: Left screw guide 81: Right screw guide 82:Fixing screw 83: Valve housing width extension 84: Valve housing height extension 85: Valve housing depth extension 86: Bottom side of valve housing 87: Upper side of valve housing 88: Valve Box 89: Feeder channel 90: Valve box entrance 101: Piezoelectric Bender 102: Valve channel 103: Sealing element 104: Valve seat 105: Contact pin 106:Leaf spring 108: Cassette housing 111: outlet flange 112: Upper side 113: Collection plate groove, valve module outlet connector 114: bottom side of collecting plate 201: Spoiler Throttle 202: Middle axis 203:Throttle sleeve 204: outer surface of throttle sleeve 205: First guide segment 206: Sealing section 207: Second guide segment 208: Throttle sleeve groove 209: throttling sleeve inflow section 210: throttle sleeve retaining section 211: throttle sleeve outflow section 212: throttle sleeve inlet 213: throttle sleeve outlet 214: Inflow plate 215: Throttle plate 216: Outflow board 217: Inflow hole 218: throttle hole 219: Outflow hole 221: Throttle disc 222: Distance Ring 223: Distance Ring 224: axial end face 225: Axial end face 226: Radial hole 227: Sealing ring 228: Collar 231:Outer diameter 232:Outer diameter 233: Outer diameter of sealing section

Claims

1. A mass flow controller (1) for providing a fluid mass flow rate, comprising a valve module (2) and a measuring assembly (3), wherein the valve module (2) has a supply connector (7) for connection to a fluid source and an outlet connector (113) for providing the fluid mass flow rate to the measuring assembly (3), wherein at least two valve assemblies (72) are provided in the valve module (2) between the supply connector (7) and the outlet connector (113), the valve assemblies being configured to each proportionally influence the fluid mass flow rate, and the measuring assembly (3) has an inlet connector (43) for connection to the outlet connector (113) and a working connector (8) for connection to a fluid source. A fluid consumption device is connected, and a working channel (42) extends between the inlet connector (43) and the working connector (8), wherein a flow throttling device (201) is provided, and the working channel (42) is equipped with a pressure sensor assembly (61, 62) for measuring the pressure difference at the flow throttling device (201), and has a control device (75) electrically connected to the pressure sensor assembly (61, 62) and connected to the valve module (2), and is configured to calculate the fluid mass flow rate in the working channel (42) from the sensor signals of the pressure sensor assembly (61, 62), and to control the valve assembly (72) to maintain the fluid mass flow rate at a desired value, wherein... The flow throttling is designed as a turbulent throttling (201) having at least two flow guiding elements taken from the following group: an inflow plate (214) having at least one inflow hole (217), a throttling plate (215) having at least one throttling hole (218), and an outflow plate (216) having at least one outflow hole (219). The two flow guiding elements are provided at a distance from each other in the working channel (42), and the at least one inflow hole (217), the at least one throttling hole (218), and the at least one outflow hole (219) are each spatially offset from each other in a direction transverse to the central axis (45) of the working channel (42).

2. As in request item 1, the mass flow controller (1), wherein, The at least one inlet orifice (217), the at least one throttling orifice (218), and the at least one outlet orifice (219) are offset from each other so as not to overlap on a projection plane transverse to the central axis (45).

3. As in request item 1, the mass flow controller (1), wherein, The inflow plate (214) has a plurality of inflow holes (217) that are radially distanced from the central axis (45), and / or the throttling hole (218) of the throttling plate (215) is coaxial with the central axis (45), and / or the outflow plate (216) has a plurality of outflow holes (219) that are radially distanced from the central axis (45).

4. As in request item 3, the mass flow controller (1), wherein, The total cross-section of the inflow orifice (217) is equal to or greater than the cross-section of the throttling orifice (218), and / or the cross-section of the throttling orifice (218) is equal to or greater than the total cross-section of the outflow orifice (219).

5. As in request item 1, the mass flow controller (1), wherein, The throttling plate (215) is designed as a disk (221) through which the throttling orifice (218) passes from an axial end face (224) to an axial end face (225), and a collar (222) extends axially from the axial end face (224) to provide a flat surface to the inflow plate (214), and / or a distance ring (223) extends axially from the axial end face (225) to provide a flat surface to the outflow plate (216).

6. As in request item 1, the mass flow controller (1), wherein, All inflow holes (217) have the same diameter at the same angular division and the same radial distance from the central axis (45) to be formed on the inflow plate (214), and / or all outflow holes (219) have the same diameter at the same angular division and the same radial distance from the central axis (45) to be formed on the outflow plate (216).

7. As in request item 1, the mass flow controller (1), wherein, The throttling orifice (218) extends axially along one of the central axes (45) at a time equivalent to 2 to 10 times the axial extension of the inflow orifice (217) and / or at a time equivalent to 2 to 10 times the axial extension of the outflow orifice (219).

8. As in request item 1, the mass flow controller (1), wherein, The throttling device (201) includes the inflow plate (214), the throttling plate (215), and the outflow plate (216), and the inflow plate (214), the throttling plate (215), and the outflow plate (216) are disposed on a throttling sleeve (203).

9. The mass flow controller (1) as requested in item 1, wherein, The valve module (2) has multiple valve boxes (88) with their extension axes parallel to each other and each accommodating a valve assembly (72). The inlet (90) of the valve box (88) is adjacent to the outlet connector (113), and the outlet connector (113) radially enters the working channel (42).

10. The mass flow controller (1) as requested in item 9, wherein, Each valve assembly (72) has at least one valve passage (102) extending between the supply connector (7) and the outlet connector (113), wherein a valve seat (104) and a piezoelectric bender (101) are provided, and the piezoelectric bender (101) carries a sealing element (103) and opens or closes the valve seat (104) according to one of the functional positions of the piezoelectric bender (101).

11. The mass flow controller (1) as requested in item 1, wherein, The pressure sensor assembly (61, 62) has a first pressure sensor, particularly a first absolute pressure sensor (61), which is connected upstream of the flow throttling (201), particularly the turbulence throttling, to the working channel (42), and the pressure sensor assembly (61, 62) has a second absolute pressure sensor (62), which is connected upstream of the flow throttling (201), particularly the turbulence throttling, to the working channel (42).

12. As in request item 1, the mass flow controller (1), wherein, The pressure sensor assembly has a first absolute pressure sensor (61) connected upstream of the flow throttling (201), particularly the turbulence throttling, to the working channel (42), and the pressure sensor assembly has a differential pressure sensor (66) connected to a first differential pressure measurement point (67) located upstream of the flow throttling (201) in the working channel (42) and a second differential pressure measurement point (68) located downstream of the flow throttling (201), particularly the turbulence throttling, in the working channel (42).

13. The mass flow controller (1) as requested in item 11, wherein, The working channel (42) has a rest area (48) designed as a blind hole in a spatial direction parallel to the intermediate axis (45) and opposite to the main flow direction (47), and the first absolute pressure sensor (61) is located in the rest area (48).

14. The mass flow controller (1) as requested in items 1 to 13, wherein, The control device (75) forms an interface (4) for power supply and communication with an AC network selected from the following groups: Modbus serial communication protocol, I / O connection, EtherCat, Profibus standard, DeviceNet, Ethernet-IP, and Profitnet.

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