Mass flow controller

Abstract

The invention relates to a mass flow controller (1) for providing a fluid mass flow, comprising a valve module (2), in which at least two valve devices (72) are arranged between a supply connection (7) and an output connection (113), and comprising a measuring device (3), the measuring device (3) comprising an input connection (43) for connecting to the output connection (113) and a working connection (8) for connecting to a fluid consumer, a working channel (42) extends between the input connection (43) and the working connection (8), in which working channel a throttle device (201) is arranged, and the working channel (42) is provided with a pressure sensor device (61, 62) for measuring a pressure difference at the throttle device (201), and having an actuating device (75) which is electrically connected to the pressure sensor device (61, 62) and is connected to the valve module (2), the actuating device is designed to determine a fluid mass flow in the working channel (42) as a function of a sensor signal of the pressure sensor device (61, 62) and to actuate the valve device (72) in a controlled manner.

Description

Technical Field

[0001] This invention relates to a mass flow controller for providing fluid mass flow rate. Background Technology

[0002] A fluid control device is known from US 101 656 684 B2, which enables the establishment of a cable connection even when several fluid control devices are arranged adjacently. The fluid control device includes a fluid control unit for controlling the flow rate or pressure of a fluid, a circuit board for receiving or transmitting signals to the fluid control unit, a housing for accommodating the fluid control 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 control device further includes a connecting plate designed to be mounted on the device-side connector. The connecting plate is fixed to the circuit board, and at least a portion of the connecting plate makes surface contact with the circuit board, or the circuit board overlaps the circuit board in a way that maintains a distance therebetween. Summary of the Invention

[0003] The object of this invention is to provide a mass flow controller with a compact structure. This object is achieved by means of the following features, addressing the mass flow controllers of the type described above for providing fluid mass flow. The mass flow controller includes a valve module and a measuring device. The valve module has a supply interface for connecting to a fluid source and an output interface for providing fluid mass flow to the measuring device. At least two valve devices are provided between the supply and output interfaces in the valve module, each valve device being configured to partially influence the fluid mass flow. The measuring device has an input interface for connecting to the valve module's output interface and a working interface for connecting to a fluid consumption device. A working channel extends between the input and working interfaces, in which a throttling device is provided. A pressure sensor is configured to measure the pressure difference before and after throttling in the working channel. An operating device is electrically connected to the pressure sensor and to the valve module. The operating device is designed to detect the fluid mass flow in the working channel using the signal from the pressure sensor and to controllably operate the valve devices to maintain a set value for the fluid mass flow.

[0004] The purpose of the valve devices in the valve module is to influence the fluid flow rate supplied at the supply interface of the valve module from a fluid source, such as a compressed air source or a process air source, so that the desired fluid mass flow rate can be provided at the working interface of the mass flow controller. The valve devices of the valve module are preferably designed to throttle the maximum fluid mass flow rate supplied by the fluid source to the required fluid mass flow rate at the working interface, by means of a throttling effect generated by at least two valve devices disposed in the valve module. Particularly preferred is that each valve device in the valve module can individually and freely adjust this throttling effect.

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

[0006] The use of multiple valve devices in a valve module allows for a particularly compact configuration of the valve module and its mass flow controller within one of the three spatial directions of a Cartesian coordinate system. These spatial directions may, for example, indicate the width, length, and height of the valve module. This compact configuration arises from the fact that each valve device has a small dimension in one spatial direction and is arranged adjacent to each other in another. For example, the valve devices may be square in shape with a circular, rectangular, or square cross-section and are arranged adjacent to each other within the valve module in a spatial direction perpendicular to its longest side.

[0007] The fluid mass flow rate originates from the valve module supply interface, passes through at least two valve devices located within the valve module, and exits from the valve module's output interface before being directly supplied to the input interface of a measuring device. Mechanical separation can be implemented between the valve module and the measuring device, with a seal provided between the output and input interfaces. Alternatively, the valve module and the measuring device can belong to the same structural group.

[0008] In addition to the input interface, the measuring device also includes a working interface for connecting a fluid consumption device, such as a fluid actuator or a reaction tank, which requires a default fluid mass flow rate supply when executing the production process.

[0009] Between the input interface and the working interface, there is a working channel extending within the measuring device, which may also be referred to as the measuring section. A flow throttling mechanism is incorporated within this working channel, designed to generate a pressure drop between the input and working interfaces that depends on the fluid mass flow rate. This pressure difference can be measured, and the fluid mass flow rate flowing through the working channel can be calculated from the pressure difference using a suitable computational model.

[0010] Using a flow throttling method can create a significant pressure difference across the flow throttling between the first upstream measurement point and the second downstream measurement point in the working channel.

[0011] To measure the pressure drop across the flow throttling, a pressure sensor is configured in the working channel and electrically connected to the control device. The pressure sensor can detect the pressure difference across the flow throttling; therefore, the pressure difference signal generated directly by the pressure sensor can be submitted to the control device, or multiple discrete pressure signals can be submitted to the control device for further processing.

[0012] The purpose of the control device is to calculate a pressure difference from the sensor signal of the pressure sensor device, and then use a mathematical model to calculate the current fluid mass flow rate in the working channel from the pressure difference. Next, the control device compares the calculated fluid mass flow rate with a pre-defined (expected) fluid mass flow rate. If there is a difference between the calculated fluid mass flow rate and the pre-defined fluid mass flow rate, one or more control signals to the valve module will be generated to minimize the difference. The control signals provided by the control device are converted in the valve module, causing the valve module to throttle and generate the required fluid mass flow rate. A closed control loop (dead loop) ensures that the mass flow controller provides the fluid mass flow rate to the working interface.

[0013] Further improvements to the invention are described in the appendices to the patent claim.

[0014] Significantly, the fluid throttling is designed as a turbulent throttling device, comprising at least two flow guiding components selected from the group consisting of an inlet plate having at least one inlet orifice, a throttling plate having at least one throttling orifice, and an outlet plate having at least one outlet orifice. The two flow guiding components are arranged spaced apart from each other in the working channel, and the at least one inlet orifice, at least one throttling orifice, and at least one outlet orifice are staggered from each other in a spatial direction transverse to the central axis of the working channel.

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

[0016] The basis of the function of the turbulent flow throttle is that the fluid mass flow rate is directed and diverted multiple times, especially at least twice, through the turbulent flow throttle, and thus undergoes multiple changes in flow direction, thereby achieving the desired significant pressure drop on the turbulent flow throttle.

[0017] Therefore, at least two, preferably three, flow guiding components are provided on the turbulent flow throttle, each pierced by one or more grooves. The grooves of the flow guiding components are arranged adjacent to each other, and the flow guiding components are designed and arranged on the projection plane transverse to the main flow direction of the fluid mass flow rate, especially transverse to the central axis of the outlet channel, and the projection lines of the grooves of adjacent flow guiding components do not overlap.

[0018] Depending on the design of the flow guiding assembly and the fluid pressure supplied at the supply interface, the fluid in the flow guiding assembly (inflow plate and / or throttling plate and / or outflow plate) flows through the grooves (inflow orifice and / or throttling orifice and / or outflow orifice) at a subsonic speed (subcritical flow mode) or a supersonic speed (supercritical flow mode). Turbulent flow throttles operating in a subcritical flow mode require more construction space. Conversely, turbulent flow throttles operating in a supercritical flow mode require a more streamlined construction. Depending on the specific application of the mass flow controller, the turbulent flow throttle is designed to operate in either a subcritical or supercritical flow mode throughout the entire specific mass flow control range.

[0019] Depending on the design of each turbulence throttle, it always maintains the same throttling characteristics regardless of the flow direction. This allows the mass flow controller's supply interface to be connected to both a pressurized fluid source and a low-pressure fluid source. However, sometimes it may be necessary to modify the valve module to adapt to the fluid source.

[0020] Preferably, the at least one inlet orifice, at least one throttling orifice, and at least one outlet orifice are arranged non-overlappingly and staggered from each other on a projection plane transverse to the central axis. This forces the gas molecules in the fluid flow to undergo multiple changes in flow direction, which are essential for ensuring high accuracy in differential pressure measurement. Through the deflection arrangement between the at least one inlet orifice and the at least one throttling orifice, and between the at least one throttling orifice and the at least one outlet orifice, no gas molecule can pass through the turbulent flow throttle along a streamline parallel to the central axis of the working channel.

[0021] Advantageously, the inflow plate has multiple inflow holes with radial distances relative to the central axis, and / or the throttling holes of the throttling plate are coaxial with the central axis, and / or the outflow plate has multiple outflow holes with radial distances relative to the central axis.

[0022] In another embodiment of the invention, the total cross-section of the inlet orifice is equal to or greater than the cross-section of the throttling orifice, and / or the cross-section of the throttling orifice is equal to or greater than the total cross-section of the outlet orifice. The total cross-section refers to the cross-section resulting from the sum of all cross-sections of the inlet orifice or outlet, and is related to the cross-section of the throttling orifice, preferably being a single cross-section. As long as the total cross-section of the inlet and / or outlet orifice is equal to the cross-section of the throttling orifice, then under additional conditions—that is, when the distance between the inlet plate and the throttling plate is equal to the distance between the outlet plate and the throttling plate—the throttling effect of the turbulent flow throttling device is unaffected by the flow direction. If such flow direction independence is not necessary, the total cross-section of the inlet orifice can be greater than the cross-section of the throttling orifice. Alternatively or supplementarily, the total cross-section of the outlet orifice can be smaller than the cross-section of the throttling orifice. This enhances the throttling effect of the turbulent flow throttling device, and thus achieves a higher pressure differential at the same fluid flow rate compared to a turbulent flow throttling device with independent flow direction.

[0023] In another embodiment of the invention, the throttling plate is designed as a disc. A throttling orifice extends from the front circular surface to the rear circular surface, and a front annular flange extends axially from the front circular surface, the front annular flange being configured to contact the inflow plate surface, and / or a rear annular flange extends axially from the rear circular surface, the rear annular flange being configured to contact the outflow plate surface. Thus, in addition to its throttling function—determined by the arrangement of the throttling orifice and its inflow orifice relative to the inflow plate and / or the outflow orifice relative to the outflow plate—the throttling plate also has the function of ensuring a predetermined distance between the inflow plate and / or the outflow plate. For this purpose, the throttling plate has a disc-shaped base, which can also be described as having a cylindrical cross-section with a central throttling orifice. From the front circular surface of this base, the front annular flange can extend axially, having an end face away from the base for contacting the inflow plate. From the rear circular surface of this base, the rear annular flange can extend axially, having an end face away from the base for contacting the outflow plate. The inner diameter of the front annular flange and / or the inner diameter of the rear annular flange are preferably selected so that there is no need to worry about the fluid flow rate being affected between the inflow plate and the throttling plate, and / or between the throttling plate and the outflow plate.

[0024] Advantageously, all inlet orifices are constructed on the inlet plate with the same angular division, the same orifice diameter, and the same radial distance relative to the central axis, and / or all outlet orifices are constructed on the outlet plate with the same angular division, the same orifice diameter, and the same radial distance relative to the central axis. This ensures that the fluid flow rate supplied at the supply interface is symmetrical about the central axis of the working channel by the inlet and / or outlet plates, resulting in advantageous flow behavior in the turbulent flow regulator. Differential pressure measurement is more stable compared to an asymmetrical zoning of the fluid flow rate supplied at the supply interface.

[0025] The preference is set such that the axial extension of the throttling orifice along the central axis is equivalent to 2 to 10 times the axial extension of the inflow orifice, and / or equivalent to 2 to 10 times the axial extension of the outflow orifice.

[0026] Advantageously, the turbulent flow throttle includes an inlet plate, a throttling plate, and an outlet plate, all housed within a throttling sleeve. This forms a separate assembly that can be manufactured, assembled, and tested independently, without involving other components of the mass flow controller, offering advantages in the mass flow controller manufacturing process.

[0027] In another embodiment of the invention, the valve module has multiple valve boxes with mutually parallel extending axes, each housing a valve device. The inlet of each valve box is adjacent to an output interface, which radially connects to a working channel. The starting point here is that each valve device has its own housing, and its functionality can be tested before assembly into each valve box. Furthermore, it is envisioned that each valve device seals its valve box at its inlet area, allowing all valve boxes to be pressurized by the pressure fluid at the supply interface. Preferably, one or more output ports are present on the front end face of the valve device protruding from the valve box, and a portion of the fluid flow released by each valve device flows from the output ports toward the output interface. Additionally, the output interface radially connects to the working channel, which is preferably designed as a cylindrical cavity. Thus, the fluid flow has already been redirected during the transition from the valve module to the measuring device.

[0028] Advantageously, each valve device has at least one valve channel extending between a supply port and an output port, in which a valve seat and a piezoelectric bender are disposed. The piezoelectric bender carries a sealing element, and the valve seat is closed or opened depending on the functional position of the piezoelectric bender. For example, the valve seat is constructed on the inner wall of the valve channel, serving as an inlet for a connection hole, in fluid communication with each output port of the valve device. The piezoelectric bender located in the valve channel, together with the sealing element mounted thereon, functions to change the distance between the sealing element and the valve seat by means of shape change, particularly a flexural change, and thus 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 disposed thereon, the stretching of which changes when a voltage is applied to the piezoelectric layer. This causes the piezoelectric bender to undergo the desired shape change, particularly a flexural change. The valve device is preferably a proportional valve with a freely selectable valve cross-section that can be given by an appropriate control voltage.

[0029] Particularly preferred is that a first and a second valve seat are provided in the valve passage, and each valve seat is equipped with a sealing element with a piezoelectric bender, so that the valve device has a dual valve function. The preferred method of using this dual valve function is that the two piezoelectric benders are controlled by a control device, and if necessary, the individual control parameters of each piezoelectric bender are used to make them simultaneously open the same orifice cross section of the valve seat.

[0030] The preferred configuration is that the pressure sensor device has a pressure sensor, specifically a first absolute pressure sensor, connected to the working channel upstream of the turbulence throttle, and a second absolute pressure sensor connected to the working channel downstream of the turbulence throttle. The pressure drop across the turbulence throttle can be calculated by interpreting the sensor signals. If both pressure sensors are implemented as relative pressure sensors, an additional absolute pressure sensor is provided as an ambient pressure sensor to measure the pressure level in the working channel. Preferably, the first pressure sensor is configured as a first absolute pressure sensor, and the second pressure sensor is configured as a second absolute pressure sensor; in this case, an ambient pressure sensor is not required.

[0031] In addition, the absolute pressure level of the fluid mass flow rate in the working channel can also be determined by sensor signals. The control device can then determine the current fluid mass flow rate in the working channel based on this information.

[0032] Advantageously, the pressure sensor device has an absolute pressure sensor connected to the working channel upstream of the turbulent flow throttle, and a differential pressure sensor connected to a first differential pressure measurement point located upstream of the turbulent flow throttle in the working channel, and a second differential pressure measurement point located downstream of the turbulent flow throttle in the working channel. This type of pressure sensor device is less expensive than a pressure sensor device with two absolute pressure sensors, and is therefore particularly suitable for price-sensitive mass flow controller applications.

[0033] Advantageously, the working channel has a quiescent zone designed as a blind orifice in a spatial direction parallel to the central axis, opposite to the main flow direction of the fluid. In this quiescent zone, there is almost no fluid flow, allowing the first absolute pressure sensor to be positioned to measure at least substantially static, or even completely static, pressure. This improves the accuracy of differential pressure measurement across the throttling device.

[0034] Advantageously, the control device forms an interface for supplying power and communicating with a communication network selected from the following groups: Modbus serial communication protocol, I / O link, EtherCat Ethernet, Profibus standard, DeviceNet, Ethernet-IP, and ProfitNet. This allows for both power supply to the mass flow controller and communication between the mass flow controller and other members of the communication network. It can also be configured to communicate with a cloud database. Attached Figure Description

[0035] Advantageous embodiments of the invention will be shown in the drawings, wherein: The present invention will be further described below with reference to the accompanying drawings, which show... Figure 1 A 3D view of a mass flow controller. Figure 2 Figure 1 An exploded 3D view of the central component of the mass flow controller in the image. Figure 3 Figure 1 A plan view of the mass flow controller in the diagram. Figure 4 A schematic diagram of a mass flow controller designed as a turbulent flow throttle, which includes an inflow plate, a throttle plate, and an outflow plate. Figure 5 Figure 1 Top view of the inflow plate, and Figure 6 Figure 1 Top view of the middle throttle plate. Figure 7 A detailed view of the working channel of the mass flow controller, which is equipped with an absolute pressure sensor and a differential pressure sensor. Detailed Implementation

[0036] Figure 1 The mass flow controller 1 shown is designed as a standalone functional component for use in a fluid system (not shown). The fluid system could be, for example, a process gas supply device for product manufacturing. For instance, the mass flow controller 1 is used to deliver a predetermined mass flow of a process gas, such as nitrogen, into a work area (not shown) for processing products according to pre-defined process specifications.

[0037] To perform this task, the mass flow controller 1 must be connected to a fluid source (not shown) and a fluid consumption device (not shown). Furthermore, the mass flow controller 1 requires electrical power and, if necessary, needs to issue control or communication signals regarding the mass flow rate of fluid to be supplied by the mass flow controller 1.

[0038] To allow the mass flow controller 1 to connect to a fluid source (not shown), a supply interface 7 is provided on the front side 21 of the mass flow controller 1 as a connector for connection to a fluid pipeline (not shown). Additionally, to allow the mass flow controller 1 to connect to a consumption device (not shown), a working interface 8 is provided on the rear side 22, opposite to the front side 21 of the mass flow controller 1, as a connector for connection to a fluid pipeline (not shown). As will be explained in detail below, the fluid mass flow rate, which may originate from a fluid source (not shown), is guided by the mass flow controller 1 to the working interface 8. Here, the mass flow controller 1 is configured to influence the fluid mass flow rate so that a fluid mass flow rate conforming to a predetermined set value is provided at the working interface 8.

[0039] For example, the assembly plate 31 is fixed on the bottom side 24 of the mass flow controller 1 to facilitate the assembly of the mass flow controller 1 onto a machine base not shown in detail.

[0040] Depend on Figure 1 It can also be seen that the mass flow controller 1, on the upper side 23, for example, has an electrical interface 4 designed as a 9-pin D-Sub connector. External power can be supplied to the mass flow controller 1 through interface 4. In addition, the electrical interface 4 can be used for the mass flow controller 1 to communicate with a higher-level controller (not shown).

[0041] On the upper side 23 near the electrical interface 4, for example, a first status display 5 and a second status display 6 are provided, which can be used to optically display the status messages of the mass flow controller 1, and can be designed as light-emitting diodes, for example.

[0042] A selection switch 10 is provided on the right side 26 of the mass flow controller 1. For example, it can be designed as a DIP switch combination. By selecting different switch positions, the mass flow controller 1 can be configured to suit the user.

[0043] Figure 2 The exploded view shows Figure 1 The main functional components of the mass flow controller 1. The main functional components that need to be understood are: valve module 2 and measuring device 3, which includes channel plate 11 and sensor plate 12.

[0044] For example only, the channel plate 11 is made of a metallic material, particularly aluminum, or of plastic, and is contained within... Figure 3 Supply channel 41 is visible in the middle, and also in Figure 3 The visible working channel 42. Furthermore, the channel plate 11 has a working channel 42 on its upper side 52. Figure 2 The 3D diagram shows input interface 43. Starting from the input interface, in... Figure 3 The visible inlet channel 44 extends into the working channel 42. For example, the channel plate 11 is designed to be rectangular, while the supply interface 7 and the working interface 8 are located on opposite end faces, which are respectively the front side 21 and the rear side 22 of the mass flow controller 1.

[0045] On the left side 51 of the channel plate 11, it is preferred to be flat, and two [unclear text - possibly related to a specific surface or feature] are provided. Figure 3The visible sensor holes 57 and 58 lead into the working channel 42. Additionally, a concealed screw hole is provided on the left side 51, allowing pressure sensors 61 and 62 to be sealed to the channel plate 11. Pressure sensors 61 and 62 constitute a pressure sensor device, located on the upper side of the sensor plate 12 facing the left side 51, and can be fixed to the left side 51 of the channel plate 11 by a fixing screw 63 passing through the sensor plate 12. For example, the sensor plate 12 includes electronic circuitry (not shown in detail) for generating pressure signals from the pressure sensors 61 and 62. Furthermore, the sensor plate 12 and the control plate 75 are electrically connected (not shown), for example, via 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 plate 75. For example, it can be assumed that the electronic control circuitry on the control plate 75 also includes a controller that controls the valve device 72 located in the valve module 2 based on the sensor signals from the pressure sensors 61 and 62.

[0046] Valve module 2 is located on the upper side 52 opposite to the channel plate 11, and includes valve housing 71 and multiple valve devices 72 within valve housing 71, collection plate 73, plate retainer 74, control plate 75, upper sealing element 76, and lower sealing element 77.

[0047] The valve housing 71 has a cubic shape, and a left screw guide 80 and a right screw guide 81 are provided on the narrow sides 78 and 79 of the valve housing 71 that are opposite to each other. The two screw guides 80 and 81 are penetrated by a fixing screw 82, which can fix 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.

[0048] For example, the valve housing 71 may be configured such that the width extension 83 and the height extension 84 substantially equal to the width extension 83, while the depth extension 85 of the valve housing 71 is only a small portion of the width extension 83, such as 20 percent.

[0049] Starting from the bottom side 86 of the valve body 71, for example, there are five in Figure 3 As can be seen, the valve box 88 extends in the height extension direction 84. For example, each valve box 88 houses a cartridge-type valve device 72, which can be pushed into the valve box 88 through the inlet 90 of each valve box 88, as will be described below. Figure 3 Further explanation.

[0050] In the embodiment of the mass flow controller 1 (not shown), if all of the above is not required... Figure 2 and 3 The valve device 72 shown can be configured such that, in one or more valve boxes 88, only a position holder is provided instead of the valve device 72.

[0051] A plate retainer 74 is provided on the opposite side of the upper side 87 of the valve body 71 to accommodate the control plate 75.

[0052] The control board 75 is configured as a printed circuit board (leadboard) that carries electrical and electronic components (not detailed in detail) and constitutes the control device for the mass flow controller 1. For example, in addition to passive electrical components such as resistors and capacitors (not shown), one or more microcontrollers or microprocessors are also provided on the control board 75, which can perform fluid mass flow control as further described below.

[0053] Since each valve device 72, by way of example, has two piezoelectric benders 101, which will be further described below, the control panel 75 is also equipped with a high-voltage component (not shown), which is provided for supplying individual high voltage, particularly DC voltage in the range of 250 volts to 500 volts, to supply each piezoelectric bender 101 of each valve device 72. The preferred configuration is that all piezoelectric benders 101 of all valve devices 72 are controlled by the operating device on the control panel 75, causing each valve device 72 to flow through a substantially equal proportion of fluid mass flow rate to the working interface 8. This may differ from... Figure 3 As shown, some or all valve devices 72 are also provided with only one piezoelectric bender 101.

[0054] In the simplified configuration of the mass flow controller 1 (not shown), the valve assembly has two piezoelectric benders, or each of the two valve assemblies has a piezoelectric bender, such that at least one dual valve function is always available.

[0055] Depend on Figure 3 It is known that the piezoelectric bender 101 of the valve device 72 passes through the contact pin 105 of the plate retainer 74 and is electrically connected to the control board 75.

[0056] In addition, by Figure 3 It can be seen that each valve device 72 has a valve channel 102, which is formed in... Figure 2 and 3 The interior of the cartridge housing 108 of each valve device 72 is visible. The valve channels 102 of the valve device 72 communicate fluidly with the feed channel 89 of the valve housing 71, and the feed channel itself is connected to the supply channel 41 via the branch channel 53 on the channel plate 11. Therefore, all valve channels 102 of the valve device 72 are pressurized in the same way by a uniform fluid pressure supplied by the supply interface 7.

[0057] Depend on Figure 3As can be seen, each pair of piezoelectric benders 101 are arranged in a mirror image manner within each cartridge housing 108. Furthermore, the piezoelectric benders 101 are pressed by leaf springs 106, also located within valve passages 102, onto a support blade (not further shown) within the valve passage 102. This support blade is adapted to the strip-shaped piezoelectric benders 101 so that when a high voltage is applied to the corresponding contact pins 105, the piezoelectric benders 101 undergo a bending change. As a result, the sealing elements 103 on the opposing surfaces of the piezoelectric benders 101 of each valve device 72 are raised by the opposite valve seats 104. Figure 3 The detailed drawing clearly shows this. It should be noted that, since it is a cross-sectional view, only the sealing element 103 of the right piezoelectric bender 101 is visible. The same applies to the valve seat 104, which also only shows the right piezoelectric bender 101.

[0058] Starting from each valve seat 104, an outlet channel (not shown in detail) extends within the cartridge housing 108, through which portions of the fluid mass flow through the valve seat 104 can exit the cartridge housing. Within this outlet channel, in... Figure 2 The visible outlet flange 111 protrudes from the collection plate 73, which is basically designed as a flat parallel plate, extending towards each valve device 72 and sealingly connecting with the outlet channel. Figure 3 As can be seen from the cross-sectional view, the collecting plate 73 has a square groove 113 on the bottom side 114, which forms a collection chamber for a portion of the fluid mass flow rate, collecting a portion of the fluid mass flow rate provided by each valve device 72 through the outlet channel and the associated outlet flange 111.

[0059] Starting from groove 113, which can also be called the output interface of valve module 2, the fluid mass flow rate enters the input interface 43 of channel plate 11 and is guided into inlet channel 44. Inlet channel 44 has inlet channel axis 46, which is transverse to the central axis 45 of working channel 42 and enters radially into inlet channel 44. Since working channel 42 extends straight along central axis 45 to working interface 8, the fluid mass flow rate makes a right-angle turn at central axis 45 when exiting from inlet channel 44 and can flow out to working interface 8 from there. Thus, a main flow direction is symbolically drawn in working channel 42, parallel to central axis 45.

[0060] For example, the working channel 42 is configured such that it extends along the central axis 45 past the inlet channel 44 in the opposite direction to the main flow direction 47, thus forming a section of the working channel 42. This section is formed in a blind-hole manner and is called the quiescent zone 48. Due to the aforementioned reversal of the fluid mass flow rate, starting from the input interface 43, the flow direction is reversed to the main flow direction 47 within the working channel 42. Fluid pressure can be detected in the quiescent zone 48 because the dynamic portion of the fluid pressure is very small or even disappears in the quiescent zone, and it is mainly or even entirely static pressure. Therefore, in the quiescent zone 48, within the working channel 42, a first sensor hole 57 is provided transversely to the central axis 45, and a first pressure sensor 61 on the control board 12 is inserted into the sensor hole. A second sensor hole 58 is also provided transversely to the central axis 45 within the working channel 42, and the second sensor hole 58 is... Figure 3 The area is obscured by the turbulence throttle 201, which will be described further below, and is therefore indicated only by dashed lines. The second sensor 62 is inserted into the second sensor hole 58, and the second sensor 62 is also located on the control board 12.

[0061] In order to reliably and accurately measure the differential pressure within the working channel 42, the working channel 42, for example, is equipped with a throttling device designed as a turbulent throttling device 201, which extends completely across the cross-section of the working channel 42 and is located between the inlet channel 44 and the working interface 8.

[0062] exist Figure 4 The turbulence throttle 201 shown in detail is constructed as an independent assembly, which can be installed and functionally tested independently of other components of the mass flow controller. The turbulence throttle 201 includes, for example, a tubular throttling sleeve 203, which is rotationally symmetrical about the intermediate axis 202 and extends along the intermediate axis 202.

[0063] The outer surface 204 of the throttling sleeve 203, for example, consists of three sections adjacent to the central axis 202, namely a first guide section 205, a sealing section 206, and a second guide section 207.

[0064] The first guide section 205 has a first outer diameter 231, which is substantially relative to the inner diameter of the first throttling section 49 that accommodates the first guide section 205. For example, the first guide section 205 and the first throttling section 49 may be configured to have mating external and internal threads, such that the turbulence throttling device 210 can be screwed into the working channel 42.

[0065] The outer diameter 233 of the sealing section 206 of the first guide section 205 and the second guide section 207 is smaller than that of the two guide sections 205 and 207. When the turbulent flow throttle 201 is assembled on the throttling section 49 of the working channel 42, it forms a first annular channel 54 with the throttling section 49, in which a sealing ring 227 is provided to ensure that the throttling sleeve 203 seals the throttling section 49. In addition, the second guide section 207 has an outer diameter 232 similar to or the same as that of the first guide section 205. Since the working channel 42 has a second throttling section 50 adjacent to the throttling section 49 in the main flow direction 47, which has a larger outer diameter, the turbulent flow throttle 201 and the working channel 42 form a second annular channel 55, which is restricted by a radially outward protruding collar 228 formed on the end side of the throttling sleeve 203. The second annular channel 55 is like a static zone 48 in terms of fluid technology, located on the other side of the main flow of fluid mass flow, and the second pressure sensor 62 is located in this second annular channel 55.

[0066] As a mere example, the groove 208 of the throttling sleeve 203, which is rotationally symmetrical about the central axis 202, can be divided into an inflow section 209, a holding section 210, and an outflow section 211. The inflow section 209 and the outflow section 211 have a diameter larger than that of the holding section 210. As a mere example, both the inflow section 209 and the outflow section 211 gradually taper from the holding section 210 until they reach the inlet 212 and the outlet 213, respectively.

[0067] Multiple flow guiding components are provided in the inflow section 209, which can generate the desired turbulent throttling function when the gaseous fluid flows through the turbulent throttling device 201. Starting from the inflow hole 212, the inflow section 209 is provided with an inflow plate 214, a throttling plate 215 directly adjacent to the inflow section 209 along the intermediate axis 202, and an outflow plate 216 directly adjacent to the throttling plate 215 along the intermediate axis 202.

[0068] Depend on Figure 5 As can be seen, the inflow plate 214 is circular, designed as a planar parallel plate, and has multiple inflow holes 217. For example, the inflow holes are arranged with the same angular component on a common portion circle 220. For instance, the inflow plate 214 can be made of a metal sheet, with the inflow holes 217 manufactured using a laser cutting or etching process. Alternatively, the inflow plate can also be made of plastic material, particularly produced using plastic injection molding.

[0069] Preferably, the inflow plate 214 and the outflow plate 216 have the same structure.

[0070] Compared to the inflow plate 214 and the outflow plate 216, the throttling plate 215 has a significantly larger axial extension along the central axis 202. Functionally, the throttling plate 215 can be divided into a throttling disk 221 and a front distance ring 222 and a rear distance ring 223. The throttling disk 221 is circular and has an unmarked outer diameter, slightly smaller than the inner diameter of an equally unmarked inflow section 209. The throttling disk 221 has a throttling orifice 218, coaxial with the outer diameter of the throttling disk 221. For example only, the throttling orifice 218 is circular. Figure 4 As can be seen, the throttling disc 221 extends axially along the central axis 202, approximately seven times the axial extension of the inflow plate 214 and the outflow plate 216. On opposite axial end faces 224 and 225, annular distance rings 222 and 223 protrude from the throttling disc 221, serving as axial distance maintainers between the inflow plate 214 and the outflow plate 216. Each of the distance rings 222 and 223 has an undetermined inner diameter, chosen to ensure that the inflow hole 217 of the inflow plate 214 and the outflow hole 219 of the outflow plate 216 are not obstructed. Conversely, the distance rings 222 and 223, while specifically designed to maintain distance between the inflow plate 214 and the outflow plate 216, have no significant effect on the throttling function of the turbulence throttling device 201, which will be further explained below.

[0071] The inner diameter of the retaining section 210 is slightly smaller than the inner diameter of the lower structure assembly consisting of the inflow plate 214, the throttling plate 215, and the outflow plate 216. The purpose of the retaining section 210 is only to axially support this lower structure assembly, and it has no significant effect on the throttling effect of the turbulence throttling device 201, which will be further explained below.

[0072] The outflow section 211 has an axial extension along the central axis that is basically the same as that of the inflow section 209, and its function is to make the fluid flow smooth after passing through the aforementioned flow guiding components (inflow plate 214, throttling plate 215, outflow plate 216).

[0073] 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 the detection of the dominant fluid pressure in the outflow section 211 for the second pressure sensor 62 to detect the pressure.

[0074] Depend on Figure 5As can be seen, the projection 227 of the throttling orifice 218 on the inflow plate 214 does not overlap with the inflow orifice 217. This ensures that the flow direction of a fluid (especially a compressed air flow or a process gas flow) undergoes multiple changes as it flows through the turbulence throttling device 201. This generates the desired turbulence in the turbulence throttling device 201. The advantage of this type of turbulence is that the streamlined design of the turbulence throttling device 201 allows for the measurement of pressure differentials. The pressure value upstream or before the turbulence throttling device 201, particularly in the inlet 212 region, can differ from the pressure value downstream or after the turbulence throttling device 201 (particularly in the radial orifice 226), allowing for accurate pressure differential measurement. From this pressure differential measurement, the fluid mass flow rate through the turbulence throttling device 201 can be calculated with high precision.

[0075] In principle, the mass flow controller 1 is used in a fluid-consuming device to provide the mass flow rate of the fluid. The mass flow controller 1 can also be used as a pressure controller.

[0076] Figure 7 Display a cross-sectional view of the channel board 11 and its working channel 42, as a reference for... Figure 3 The only difference is that it doesn't use an absolute pressure sensor 62, but instead uses a differential pressure sensor 66, configured to measure the pressure difference in the mass flow controller 1. For this purpose, the differential pressure sensor 66 has a first measuring point 67, directly located before the turbulence throttle 201, for pressure detection. Furthermore, the differential pressure sensor 66 has a second measuring point 68, for pressure detection in the second ring channel 55. The detection method of the first pressure sensor 61 is the same as... Figure 3 The same applies to region 48 in the static zone. It can also be compared with... Figure 7 Unlike other measurements, the first measurement point 67 is also set in the stationary area 48.

Claims

1. A mass flow controller (1) for providing a fluid mass flow rate, the mass flow controller (1) having a valve module (2) and a measuring device (3), wherein the valve module (2) has a supply interface (7) for connecting to a fluid source and an output interface (113) for providing the fluid mass flow rate to the measuring device (3), wherein at least two valve devices (72) are provided between the supply interface (7) and the output interface (113) of the valve module (2), the valve devices being configured to partially influence the fluid mass flow rate, and the measuring device (3) has an input interface (43) for connecting to the output interface (113) and a working interface (8) for connecting to a fluid consumption device, wherein the mass flow controller (1) has at least two valve devices (72) between the supply interface (7) and the output interface (113 ... at least two valve devices (72) between the supply interface (7) and the output interface (113), the valve devices being configured to partially influence the fluid mass flow rate, and the measuring device (3) has at least two valve devices (72) for connecting to the supply interface (7) and the output interface (113), the valve devices being configured to partially influence the fluid mass flow rate, and the measuring device (3) has at least two valve devices (72) for connecting to the supply interface (7) and the output interface (113), the valve devices being configured to partially influence the fluid mass flow rate, and the measuring device (3) has at least two valve devices (72) for connecting to the supply interface (7) and the output interface (113), the valve devices being configured to partially influence the fluid mass flow rate, and the measuring device (3) has A working channel (42) extends between the input interface (43) and the working interface (8), in which a throttling device (201) is provided, and the working channel (42) is equipped with pressure sensor devices (61, 62) for measuring the pressure difference in the throttling device (201), and the mass flow controller (1) has a control device (75) electrically connected to the pressure sensor devices (61, 62) and connected to the valve device (72), and the control device is configured to determine the fluid mass flow rate in the working channel (42) according to the sensor signal of the pressure sensor devices (61, 62) and to controllably control the valve device (72) to maintain the set value of the fluid mass flow rate.

2. The mass flow controller (1) according to claim 1, characterized in that, The throttling device is designed as a turbulent throttling device (201) having at least two flow guiding components selected from the group consisting of 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 components are arranged spaced apart 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 staggered from each other in a spatial direction transverse to the central axis (45) of the working channel (42).

3. The mass flow controller (1) according to claim 2, characterized in that, The at least one inlet hole (217), the at least one throttling hole (218), and the at least one outlet hole (219) are arranged non-overlappingly and staggered from each other on a projection plane transverse to the central axis (45).

4. The mass flow controller (1) according to claim 2, characterized in that, 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).

5. The mass flow controller (1) according to claim 4, characterized in that, The total cross-section of the inflow hole (217) is equal to or greater than the cross-section of the throttling hole (218), and / or the cross-section of the throttling hole (218) is equal to or greater than the total cross-section of the outflow hole (219).

6. The mass flow controller (1) according to any one of claims 2 to 5, characterized in that, The throttling plate (215) is designed as a disk (221) through which the throttling orifice (218) passes from the front circular surface (224) to the rear circular surface (225). A front annular flange (222) extends axially from the front circular surface (224) and is configured to contact the surface of the inflow plate (214). And / or a rear annular flange (223) extends axially from the rear circular surface (225) and is configured to contact the surface of the outflow plate (216).

7. The mass flow controller (1) according to any one of claims 2 to 6, characterized in that, All inlet holes (217) are constructed on the inlet plate (214) with the same angular division, the same diameter and the same radial distance relative to the central axis (45), and / or all outlet holes (219) are constructed on the outlet plate (216) with the same angular division, the same diameter and the same radial distance relative to the central axis (45).

8. The mass flow controller (1) according to any one of claims 2 to 7, characterized in that, The throttling orifice (218) extends axially along the central axis (45) in a manner equivalent to 2 to 10 times the axial extension of the inflow orifice (217), and / or in a manner equivalent to 2 to 10 times the axial extension of the outflow orifice (219).

9. The mass flow controller (1) according to any one of claims 2 to 8, characterized in that, The turbulent flow throttle (201) includes the inflow plate (214), the throttle plate (215), and the outflow plate (216), and the inflow plate (214), the throttle plate (215), and the outflow plate (216) are disposed on the throttle sleeve (203).

10. The mass flow controller (1) according to any one of claims 1 to 9, characterized in that, The valve module (2) has multiple valve boxes (88) with parallel extended axes and each accommodating a valve device (72). The inlet (90) of the valve box (88) is adjacent to the output interface (113), and the output interface (113) radially enters the working channel (42).

11. The mass flow controller (1) according to any one of claims 9 or 10, characterized in that, Each valve device (72) has at least one valve passage (102) extending between the supply port (7) and the output port (113), in which 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 the functional position of the piezoelectric bender (101).

12. The mass flow controller (1) according to any one of claims 1 to 11, characterized in that, The pressure sensor device (61, 62) has a first pressure sensor, particularly a first absolute pressure sensor (61), which is connected upstream of the throttling device (201), particularly the turbulent throttling device, to the working channel (42), and the pressure sensor device (61, 62) has a second absolute pressure sensor (62), which is connected downstream of the throttling device (201), particularly the turbulent throttling device, to the working channel (42).

13. The mass flow controller (1) according to any one of claims 1 to 11, characterized in that, The pressure sensor device has a first absolute pressure sensor (61) which is connected to the working channel (42) upstream of the throttling device (201), particularly the turbulent throttling device, and the pressure sensor device has a differential pressure sensor (66) which is connected to a first differential pressure measuring point (67) located upstream of the throttling device (201) in the working channel (42) and a second differential pressure measuring point (68) located downstream of the throttling device (201) in the working channel (42), particularly the turbulent throttling device.

14. The mass flow controller (1) according to any one of claims 12 or 13, characterized in that, The working channel (42) has a stationary 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 stationary area (48).

15. The mass flow controller (1) according to any one of the preceding claims, characterized in that, The control device (75) forms an interface (4) for supplying electrical power and for communicating with a communication network selected from the group consisting of: Modbus serial communication protocol, IO link, EtherCat Ethernet, Profibus standard, DeviceNet, Ethernet-IP, and ProfitNet.

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