Mass flow control system

Abstract

The invention relates to a mass flow control system (300) comprising a carrier plate (301) which has, on a first side (302), fluid interfaces for attaching valve modules (304), wherein each fluid interface is provided with a plurality of channel openings (345), wherein each channel opening (345) is connected to an inlet channel (306, 307) or to one of a plurality of outlet channels (309), wherein the inlet channel (306, 307) extends from a first supply port (401) through the carrier plate (301) to a second supply port (401), wherein in the inlet channel (306, 307) a blocking element (406) is arranged which subdivides the inlet channel (306, 307) into a first inlet channel portion (407) and a second inlet channel portion (408), wherein the first inlet channel portion (407) is fluidically connected to at least one of the channel openings (345) allocated to the first inlet channel portion (407) and wherein the second inlet channel portion (408) is fluidically connected to at least one of the channel openings (345) allocated to the second inlet channel portion (408), and comprising a plurality of valve modules (304) each having at least one valve arrangement (325).

Description

[0001] Mass flow control system

[0002] The invention relates to a mass flow control system for the controlled provision of fluid mass flows. Such systems are intended, for example, for use in production plants to specifically supply one or more work spaces with defined fluid mass flows, in particular compressed air mass flows or process gas flows, or to specifically withdraw fluid mass flows from them to generate or maintain a negative pressure or a vacuum.

[0003] The invention is therefore based on the object of specifying a modular mass flow control system for the controlled provision of fluid mass flows, which enables a controlled provision of two fluid mass flows, in particular for the fluid supply and the fluid evacuation of work spaces.

[0004] The object is achieved by a mass flow control system for the controlled provision of fluid mass flows, with a carrier plate which has fluid interfaces on a first side for the attachment of valve modules, wherein each fluid interface is provided with a plurality of channel openings, wherein each channel opening is connected to a first inlet channel formed in the carrier plate or to one of a plurality of outlet channels formed in the carrier plate, wherein the inlet channel extends from a first inlet connection through the carrier plate to a second inlet connection, wherein a blocking element is arranged in the inlet channel, in particular one which can be freely positioned in the inlet channel and which divides the inlet channel into a first inlet channel section and a second inlet channel section which are fluidically separated,wherein the first input channel section is fluidly connected to at least one of the channel openings assigned to the first input channel section and wherein the second input channel section is fluidly connected to at least one of the channel openings assigned to the second input channel section, as well as to a plurality of valve modules each having at least one valve arrangement, each of which is designed to influence at least one fluid mass flow, wherein each of the valve modules has an input connection which is sealingly connected to the input channel via an assigned channel opening, and has an output connection which is sealingly connected to one of the output channels via an assigned channel opening, with an electronic processing unit, an electrical supply interface and with electrical control interfaces for coupling the valve modules,wherein a flow resistance is arranged in each of the output channels, and wherein each of the output channels is assigned sensor openings in the region of the flow resistance, which open out on a second side of the carrier plate facing away from the first side of the carrier plate, and wherein pressure sensors are assigned to the sensor openings, wherein the processing unit is electrically connected to the pressure sensors and to the supply interface and the control interfaces and is designed to evaluate sensor signals from the pressure sensors and to control the valve modules connected to the control interfaces for carrying out mass flow control. With the inventive design of the mass flow control system, it is possible to provide fluidly separated fluid mass flows in a controlled manner,The fluidic separation is achieved via the blocking element arranged in the inlet channel. For the controlled provision of the fluidically separated fluid mass flows, the mass flow control system forms a first fluid circuit and a second fluid circuit. The first fluid circuit is formed by the first inlet connection, the first inlet channel section, the channel openings assigned to the first inlet channel section, the flow modules sealingly connected to these channel openings, and the outlet channels to which the flow modules are sealingly connected. Analogously, the second inlet connection, the second inlet channel section, the channel openings assigned to the second inlet channel section, the flow modules sealingly connected to these channel openings, and the outlet channels to which the flow modules are sealingly connected form the second fluid circuit.

[0005] For example, a fluid mass flow, in particular in the form of a process gas, can be supplied to a working space in a controlled manner via the first fluid circuit and, at the same time, a fluid mass flow can be withdrawn from a further working space in a controlled manner, in particular in order to evacuate this further working space or to maintain a predetermined or predeterminable negative pressure therein.

[0006] By way of example, the inlet channel can comprise a first bore formed in an end face of the support plate adjacent to the first side of the support plate, and a further bore fluidly connected to this bore, which is formed in a side surface of the support plate adjacent to the first side and the end face. The locations at which the first bore pierces the end face and the second bore pierces the side face define the first inlet connection and the second inlet connection, respectively.

[0007] The channel openings are preferably fluidly connected to the second bore, in which the blocking element can also preferably be arranged. Thus, depending on the position of the blocking element, which can in particular be freely positioned in the inlet channel, a number of channel openings assigned to the first inlet channel section and a number of channel openings assigned to the second inlet channel section can be determined. Consequently, the carrier plate or the mass flow control system can be adapted to the conditions of a site of use by exchanging the carrier plate during production, wherein the number of channel openings assigned to the first inlet channel section or the second inlet channel section also determines the number of respectively assigned valve modules and thus the maximum fluid mass flow of the respective fluid circuit.

[0008] The blocking element is advantageously designed as a spherical element which has a larger diameter than the inlet channel and is made of a material which is harder than the material of the carrier plate. The blocking element can therefore be pressed into the inlet channel in order to divide the inlet channel into the first inlet channel section and the second inlet channel section, the press fit between the inlet channel and the blocking element achieving the required fluidic separation of the first inlet channel section and the second inlet channel section. Other geometries for the blocking element are also conceivable. Alternatively, the blocking element can also be a materially bonded blocking element, in particular a soldered joint or an adhesive joint.

[0009] The mass flow control system according to the invention also has a high degree of modularity, which enables the mass flow control system to be used in different configurations. For example, two or more valve modules can be connected to the carrier plate so that two consumers can be supplied with one fluid mass flow, or the first of the two valve modules can initially supply the consumer and, in the event of a malfunction in the first valve module, the supply can be switched to the second valve module. The number of valve modules used can also be adapted depending on the application. For example, five valve modules can be provided to supply five different consumers.The number of valve modules can be flexibly adjusted, since the necessary evaluation of the sensor data and the provision of control commands for the valve arrangement of the valve modules are carried out via the electronic processing device located on the main board, which can be implemented, in particular, as a processor or microcontroller. No dedicated control system is required in the valve modules.

[0010] The carrier plate is provided, on the one hand, for mechanically fixing the valve modules and, on the other hand, for a fluid connection between a fluid source, the valve modules and one or more consumers, in particular working spaces. In the event of an evacuation to be carried out, the working space to be evacuated can be interpreted as a fluid source which, for example, supplies a vacuum pump, which can be interpreted as consumption, with a fluid mass flow. For example, the carrier plate is made of plastic or of a metallic material, in particular aluminum, and preferably has a substantially cuboid shape.

[0011] The valve modules are preferably lined up adjacently along a row direction with opposite side surfaces, which are in particular the largest surfaces of the respective valve modules. The housings of the valve modules each have two side surfaces aligned parallel to one another, wherein these side surfaces are connected to one another by narrow sides and wherein at least one of these narrow sides is designed to rest on the carrier plate. It is preferably provided that this narrow side is flat and that the carrier plate is also flat, at least in the region of the fluid interfaces.

[0012] The housing of the respective valve module can, for example, be cuboid-shaped and has, on an end face which is oriented perpendicular to the narrow side which is intended for support on the carrier plate, a plurality of shafts which are in particular spaced apart from one another at a constant pitch and aligned parallel to one another. Each of the shafts extends, starting from the end face, as a recess along an extension axis into the housing of the valve module. The shafts preferably have a substantially constant cross-section and their openings are preferably located in an opening plane aligned parallel to the end face. Each of the shafts is designed to receive a valve arrangement, wherein the respective valve arrangement can be pushed into the respective shaft starting from the opening in the direction of the extension axis.The valve arrangement has a supply connection and an outlet connection, which are each designed as an orifice of a supply channel and an outlet channel of the valve arrangement, respectively. A valve seat and a valve member that can move between a closed position for the valve seat and an open position for the valve seat are arranged in the outlet channel, so that a cross-section of the outlet channel can be changed. The valve member is coupled to an actuator that can cause the valve member to move between the open position and the closed position as a function of an electrical control signal.

[0013] It is preferably provided that the valve member releases a maximum cross-section of the outlet channel in the open position and completely closes the outlet channel in the closed position.

[0014] The flow resistors arranged in the respective output channels of the carrier plate, in conjunction with the pressure sensors arranged on the main board, enable fluid mass flow measurement using the differential pressure method in the respective output channels. The flow resistor can be designed, for example, as a throttle, an orifice plate, or a Laval nozzle. The pressure sensors assigned to the output channels each protrude into the sensor openings arranged in the region of the flow resistor and are each fluidly connected to the respective output channel. Associated sealing elements are provided to ensure a fluid-tight connection between the pressure sensors and the carrier plate.The pressure sensors are arranged directly on the main board so that the electrical sensor signals provided by the sensors are fed to the electronic processing unit via the signal lines integrated in the main board and processed there.

[0015] The electronic processing unit is electrically connected to a supply board of the respective valve module via the electrical control interfaces for coupling the valve modules. This allows the electrical processing unit to send control signals to the valve assemblies arranged in the valve module.

[0016] According to the invention, the electronic processing unit is designed to carry out mass flow control for the respective output channel in order to provide a predeterminable fluid mass flow at the output connection of the respective output channel. For this purpose, the electronic processing unit controls the valve modules as a function of the measured fluid mass flow. Provision can be made for all valve arrangements assigned to an output channel to be operated simultaneously and each to have a substantially identical valve opening. With such an operating mode, a maximum fluid mass flow can be made available when all valve arrangements assigned to the respective output channel are fully open, provided the actuator of each valve arrangement releases a maximum cross-section of the respective outlet channel in the open position.

[0017] Alternatively, it can be provided that, for example, two valve arrangements of a valve module are connected in pairs to form a first group, and two further valve arrangements of the valve module are connected to form a second group. Subsequently, only the first group is initially used to control the fluid mass flow, while the second group is only activated if at least one valve arrangement of the first group fails, so that the second group can be referred to as a redundant group.

[0018] The electrical supply interface serves to supply power to the electrical and electronic components, in particular the processing device and the pressure sensors, and via the respective control interfaces also to the valve modules.

[0019] In addition, the supply interface can be designed for communication between the mass flow control system, for example, and a higher-level controller of a networked system. For this purpose, the supply interface is designed to connect the mass flow control system to a communications system. Purely as an example, the supply interface is designed for communication according to a communications standard from the group: OPC UA (Open Platform Communication Unified Architecture), bus communication system, 10 Link. In this case, data can be exchanged via the supply interface, for example with a higher-level controller, in particular a programmable logic controller (PLC), or with a control level or a cloud.

[0020] Advantageous further developments of the invention are the subject of the dependent claims.

[0021] In an advantageous embodiment of the mass flow control system, the electronic processing unit, the electrical supply interface, the electrical control interfaces, and the pressure sensors are arranged on a main board. The arrangement of the processing unit, the supply interface, the control interfaces, and the pressure sensors on the main board enables central supply and control of all components, so that all steps required for mass flow control can be carried out using the main board. Complex wiring of separately implemented boards, for example a sensor board and a control board, can be omitted. The blocking element is expediently arranged detachably in the inlet channel.It can thus be provided that the blocking element, which is designed, for example, as a screw-in blocking element, is initially not arranged in the inlet channel, which at least in sections has a thread corresponding to the thread of the blocking element, or only closes the second inlet connection in a fluid-tight manner, so that the inlet channel is not divided and the mass flow control system only has one fluid circuit starting from the first inlet connection. If the mass flow control system is to be designed for operation that requires both fluid circuits, the blocking element can be screwed into the inlet channel in order to form the first inlet channel section and the second inlet channel section and to fluidly separate them from one another.

[0022] Analogously, a separation that has been carried out can also be reversed if a second fluid circuit or the second fluid circuit is no longer required or if a larger fluid mass flow is to be provided in a controlled manner via the first fluid circuit.

[0023] In a preferred embodiment, a first sensor opening is arranged upstream of the flow resistance in the direction of flow and a second sensor opening is arranged downstream of the flow resistance in the direction of flow, wherein a first pressure sensor, which is assigned to the first sensor opening, and a second pressure sensor, which is assigned to the second sensor opening, are each designed as absolute pressure sensors. Thus, the pressure loss induced by the flow resistance can be determined as a pressure difference between the sensor signals of the first pressure sensor and the second pressure sensor, and the fluid mass flow can be calculated on this basis. The calculations required for this are carried out in the electronic processing unit.The electronic processing unit is further configured to send suitable control signals to the valve modules in the event of deviations between the currently calculated fluid mass flow and a predetermined target fluid mass flow, in order to regulate the fluid mass flow to the target fluid mass flow. In this embodiment of the first and second pressure sensors, the main board can additionally be assigned a further pressure sensor for determining an ambient pressure, the sensor signals of which are also evaluated in the electronic processing unit.

[0024] Alternatively, the first pressure sensor and the second pressure sensor can be configured as relative pressure sensors, and an ambient pressure sensor can be provided on the main board for measuring ambient pressure. This allows simpler relative pressure sensors to be used, whose measurement results can be corrected using the measured ambient pressure before calculating the fluid mass flow.

[0025] Alternatively, it is provided that the first sensor opening is arranged upstream of the flow resistance in the direction of flow and the second sensor opening has a first inlet channel and a second inlet channel, wherein the first inlet channel opens into the outlet channel upstream of the flow resistance in the direction of flow and the second inlet channel opens into the outlet channel downstream of the flow resistance in the direction of flow, wherein the first pressure sensor, which is assigned to the first sensor opening, is designed as an absolute pressure sensor and wherein the second pressure sensor, which is assigned to the second sensor opening, is designed as a differential pressure sensor or the first pressure sensor is designed as a relative pressure sensor and the second pressure sensor is designed as a differential pressure sensor and an ambient pressure sensor for measuring an ambient pressure is provided on the main board.Thus, a differential pressure gauge can advantageously be used to directly measure the differential pressure of the pressure loss induced by the flow resistance, which, in addition to the absolute pressure measured upstream of the flow resistance, is included in the calculation of the mass flow.

[0026] The valve module expediently has a plurality of output connections and contains a plurality of valve arrangements, each of which is connected to the input connection and to one output connection or to a plurality of output connections. For example, in a valve module having four valve arrangements, two valve arrangements are fluidly connected to a first output connection and the other two valve arrangements are fluidly connected to a further output connection, each output connection being sealingly connected to a respective outlet channel via a respective channel opening. In the respective outlet channel, in turn, it is possible to determine the fluid mass flow provided via the respective outlet channel. For example, two different consumers can each be supplied with a fluid mass flow simultaneously or alternately, and the respective fluid mass flow provided can be determined.Alternatively, the fluid separation between the first output connection and the second output connection makes it possible to supply the respective consumer with different fluids.

[0027] In an advantageous embodiment, a channel plate is provided on the valve module, which is designed for connecting a plurality of valve assemblies arranged in the valve module. The channel plate is designed for attachment to the front side of the valve housing. A first connecting channel and a second connecting channel are formed in the channel plate, wherein the first connecting channel is fluidically connected to the respective supply connection of the valve assembly and the second connecting channel is fluidically connected to the respective output connection of the valve assembly. The inlet connection of the first connecting channel is connected to the inlet channel via a channel opening, and the outlet connection of the second connecting channel is sealingly connected to one of the output channels via one or more channel openings.Depending on the number of valve arrangements arranged in the valve module and / or depending on the fluid mass flow to be provided, different configurations of the first connecting channel and the second connecting channel can be realized by exchanging the channel plate.

[0028] For example, it is conceivable that only two valve arrangements are arranged in a first shaft and in a second shaft of the valve module, wherein in this case the first connecting channel and the second connecting channel each have only two connections for valve arrangements.

[0029] The supply interface preferably has a data and power interface for connection to a supply module, wherein an exchangeable supply module is plugged into the supply interface and is connected to the supply interface via the data and power interface. In this way, the supply interface can be adapted to a wide variety of conditions by exchanging the supply module. For example, it is possible to provide a supply module for connection to a 50 Hz power supply or a supply module for connection to a 60 Hz power supply. The supply module also preferably contains a communication unit designed for integration into the respective communication system, so that a wide variety of communication systems can be operated by exchanging the supply module.

[0030] In a further embodiment of the mass flow control system, the carrier plate has a plurality of recesses, each of which can accommodate a plug section of the valve module for a plug-in connection between the valve module and the main board in a plugged-in state. This initially secures the valve module to the carrier plate, and the latter is correctly aligned according to its connections. Once aligned, the valve module can be secured to the carrier plate, for example, using additional fastening elements.

[0031] It is advantageous if the actuator of the valve arrangement is designed as a piezo bender. A proportional valve function can be implemented using a piezo bender, which can be designed in particular in strip form as a monomorph, bimorph, or trimorph, with or without an electrically conductive intermediate layer. By changing the radius of curvature of the piezo bender, a change in the position of the valve element coupled to the piezo bender is brought about, and thus an influence on the cross-section of the outlet channel, so that the fluid mass flow released by the valve arrangement can be continuously adjusted by suitable control signals from the processing unit.

[0032] The valve module preferably comprises a supply board with high-voltage electronics which is provided for the electrical supply of the actuator designed as a piezo bender. In this context, high voltage is understood to mean a direct current voltage in the range of 300 V. The supply board can be adapted to the valve assemblies inserted into the valve module. However, control is still carried out via the processing device, so that the high-voltage electronics contained in the valve module only converts the control signals received from the processing unit into corresponding high-voltage signals for the actuator or actuators. In this way, the complexity of the supply board can be significantly reduced and the high-voltage electronics can be matched to the valve assemblies arranged in the valve module.This means that when the valve module is replaced, the high-voltage electronics required to supply the valve arrangements are also replaced.

[0033] In an advantageous embodiment of the invention, the processing unit is designed for individual control of each actuator. Thus, for each valve arrangement, the respective valve cross-section can be adjusted independently of the other valve cross-sections. In particular, each actuator can be electrically controlled by the processing unit using an individually adapted set of parameters.

[0034] The flow resistance is expediently designed as a turbulence throttle. The use of a turbulence throttle enables the generation of a significant pressure difference, which permits precise differential pressure measurement, while maintaining a small installation space requirement. This is particularly true when comparing the installation space requirement of the turbulence throttle with the installation space requirement of a laminar flow element. The function of the turbulence throttle is based on the fluid flow being deflected several times as it passes through the turbulence throttle and thus experiencing a multiple change in flow direction, whereby the desired significant pressure drop across the turbulence throttle can be achieved. For this purpose, at least two, preferably three, flow guide elements are arranged in the turbulence throttle, each of which is penetrated by one or more recesses.The recesses of adjacently arranged flow guide elements are arranged and designed in such a way that in a projection plane which is aligned transversely to a main flow direction of the fluid mass flow, in particular transversely to a central axis of the outlet channel, there are no overlaps between the projections of the recesses of the adjacently arranged flow guide elements.

[0035] The invention is explained in more detail below using the attached drawing, which shows:

[0036] Figure 1 is a schematic and perspective view of a mass flow control system,

[0037] Figure 2 is a perspective view of the mass flow control system from Figure 1 in an exploded view,

[0038] Figure 3 is a schematic and perspective view of a valve module in an exploded view, Figure 4 is a schematic view of a first fluidic circuit in a mass flow control system,

[0039] Figure 5 is a schematic representation of a second fluidic circuit in a mass flow control system,

[0040] Figure 6 is a schematic representation of a fluidic overall circuit in a mass flow control system,

[0041] Figure 7 is a sectional view of the mass flow control system from Figure 1 along the section plane I-I in a side view,

[0042] Figure 8 is a detailed view of an output channel from detail A in Figure 7,

[0043] Figure 9 is a side view of a turbulence throttle designed as a flow resistance in a sectional view,

[0044] Figure 10 shows an inlet plate of the turbulence throttle shown in Figure 9 in a top view,

[0045] Figure 11 shows a throttle plate of the turbulence throttle shown in Figure 9 in a plan view.

[0046] A mass flow control system 300 shown in Figure 1 is provided for the fluid supply of a plurality of consumers (not shown). Purely by way of example, the mass flow control system 300 comprises a cuboid-shaped carrier plate 301 made of aluminum, on whose upper side 302, also referred to as the first side, a plurality of valve modules 304 are attached. Figure 2 shows an exploded view of the mass flow control system 300. On a first end face 305 of the carrier plate 301, which is aligned perpendicular to the upper side 302, a first inlet connection 402 of a first inlet channel 306 and a first inlet connection 402 of a second inlet channel 307 are arranged, by way of example, which are each provided for a connection to a fluid source 308 (Figures 4 and 5).The mass flow control system 300 can be supplied with one pressurized fluid or with two pressurized fluids, in particular compressed air or process gas.

[0047] Furthermore, eight output couplings 311 are arranged purely as an example on the front side 305, to which fluid hoses (not shown) can be connected for coupling consumers (not shown).

[0048] In the illustrated embodiment, the first inlet connection 401 of the first input channel 306 and the first inlet connection 401 of the second input channel 307 each have an input coupling 310 designed as a pneumatic connector. The output couplings 311 each delimit associated output channels 309, which extend into the carrier plate 301.

[0049] By way of example only, five valve modules 304 are arranged on the support plate 301, each having a connector section 312, as shown in Figures 2 and 3. The connector sections 312 are provided for electrically connecting the valve modules 304 and each pass through a recess 313 in the support plate 301. The valve modules 304 are each attached to the support plate 301 with two fastening screws 386, 388.

[0050] The valve modules 304 are arranged adjacent to one another along an arrangement axis 303 with their largest side surfaces 315 lying opposite one another. The housing 316 of the valve modules 304 has two side surfaces 315 aligned parallel to one another, which are connected to one another by narrow sides 318, one of which can be referred to as the underside 319. In this case, it is provided that the valve modules 304 rest with the respective underside 319 on the top side 302 of the carrier plate 301. Accordingly, the housing 316 is essentially cuboid-shaped. A first valve module 304 borders with a side surface 315 on a housing 321 of a supply module 322, which is also fastened to the carrier plate 301.For fastening the supply module 322, a support plate recess 314 is provided adjacent to the end face 305, which can be closed by means of a cover plate 317 and in which the supply module 322 is accommodated in sections. The cover plate 317 is secured to the support plate 305 by means of fastening screws 320.

[0051] By way of example, the valve module 304 shown in an exploded view in Figure 3 has, on a front end face 323 which is oriented perpendicular to the underside 319, a plurality of shafts 324 (Figures 4, 5 and 6) which are spaced apart from one another at a constant pitch and aligned parallel to one another. The shafts 324 have a substantially constant cross-section and are designed to accommodate valve assemblies 325. The valve module 304 shown by way of example has four shafts 324, in each of which a valve assembly 325 is accommodated such that a first side 328 of the valve assembly 325, which has a supply connection 326 and an outlet connection 327, is arranged in the region of the end face 323. On the second side 329 of the valve arrangement 325 opposite the first side 328, four electrical connectors 330 are formed as an example, which are prepared for an electrical connection to a supply board 331.However, it is also possible that a smaller number or a larger number of shafts 324, in particular eight shafts, are present.

[0052] The electrical connectors 330 extend through a receiving web 333 formed in the region of a second end face 332 of the housing 316 opposite the first end face 323, wherein a sealing ring 335 is provided between a sealing surface 334 of the valve arrangement 325 and an invisible inner surface of the receiving web 333 facing the shaft 324, which sealing ring seals the shaft 324 against the receiving web 333 in a fluid-tight manner. In the region of an outer side 336 opposite the inner surface of the receiving web 333, a receiving space 337 is formed in the housing 321, in which the supply board 331 is received when it is connected to the electrical connectors 330. In this state, the supply board 331 partially protrudes through the plug section 312 such that an electrical connector 338 of the supply board 331 protrudes beyond the plug section 312. The receiving space 337 can be closed by means of a cover 339.In the region of the first end face 333, a channel plate 340 is arranged, in which a first connecting channel 341 and a second connecting channel 342 are formed, the first connecting channel 341 being sealingly connected to a supply connection 326 of the respective valve arrangement 325 and the second connecting channel 342 being sealingly connected to the outlet connection 327. For a fluid seal of the respective valve arrangement 325 with respect to the channel plate 340, a sealing element 344 is provided between the first side 323 and the channel plate 340.

[0053] Channel openings 345 are formed on the upper side 302 of the carrier plate 301, via which an inlet connection 346 of the first connecting channel 341 is sealingly connected to the first inlet channel 306 or the second inlet channel 307, and an outlet connection 347 of the second connecting channel 342 is sealingly connected to one of the outlet channels 309. For this purpose, a further sealing element 348 is provided that can be placed on an underside 343 of the channel plate 340. On the side 349 of the channel plate 340 facing away from the underside 343, a cover 351 is provided that is sealed with a cover seal 350 and can be fixed to the channel plate 340 by means of the fastening screw 386. By way of example, two channel openings 345 each represent a fluid interface that is assigned to the respective valve modules 304.

[0054] The pneumatic circuit described above can be seen particularly in the schematic representation of a first circuit in Figure 4. The fluid source 308 is connected, for example, via the first inlet connection 401 of the first inlet channel 306 to the mass flow control system 300 and supplies it with a fluid mass flow. In the illustrated embodiment, this fluid enters the first inlet channel 306 in the carrier plate 301, leaves it via a channel opening 345, enters the first connecting channel 341 of the channel plate 340 via the inlet connection 346 and is guided via this to the supply connection 326 of the valve arrangement 325 shown as an example in Figure 4. From there, the fluid mass flow passes via the supply connection 326 of the valve arrangement 325 via a supply channel 352 into a pressure chamber 353 formed in the valve arrangement 325.The supply channel 352, like two outlet channels 354, is formed in a nozzle carrier 355 arranged in the valve arrangement 325, wherein the pressure chamber-side opening 356 of each outlet channel 354 has a valve seat 357 which can be closed in a fluid-tight manner by means of a valve member 358 of an actuator 359 of the valve arrangement 325, designed as a piezo bender, or such that a cross-section of the outlet channel 354 can be changed by the actuator 359. It is preferably provided that the actuator 359 releases a maximum cross-section of the outlet channel 354 in an open position and completely closes the outlet channel 354 in a closed position.Depending on the set cross-section of the respective outlet channel 354, a part of the fluid mass flow passes through the respective outlet channel 354 via the associated outlet connection 327 into the second connecting channel 342, the outlet connection 347 and via the channel opening 345 into an outlet channel 309 and can be supplied from there to the consumer. To determine the fluid mass flow conducted via the outlet channel 309, a flow resistance 201, designed as a turbulence throttle by way of example, is provided in the outlet channel 309, as can also be seen in the illustrations in Figures 7 and 8, the induced pressure loss of which is measured via a first pressure sensor 361 and a second pressure sensor 362 of a main board 363, which are each assigned to sensor openings 364 which open out on a second side 365 of the carrier plate 301.In the exemplary embodiment shown, the first pressure sensor 361 and the second pressure sensor 362 are designed as absolute pressure sensors, with a first sensor opening 364 being arranged upstream of the flow resistance 201 in the direction of flow. The second sensor opening 364 has a first inlet channel 366 and a second inlet channel 367, with the first inlet channel 366 being arranged upstream of the flow resistance 201 in the direction of flow and the second inlet channel 367 being arranged downstream of the flow resistance 201 in the direction of flow.

[0055] In an embodiment not shown, the second sensor opening 364 can have only one inlet channel arranged behind the flow resistance 201. In an embodiment also not shown, the first pressure sensor 361 and the second pressure sensor 362 can be designed as relative pressure sensors, wherein in this embodiment, a further pressure sensor designed as an absolute pressure sensor is provided on the main board 363 and is configured to measure the ambient pressure.

[0056] A processing unit 368 arranged on the main board 363, which is embodied as a microcontroller by way of example, is electrically connected to the first and second pressure sensors 361, 362 as well as to a supply interface 369 and control interfaces 370. The supply interface 369 of the main board 363 is prepared for a connection to the supply module 322, via which the main board 363 is supplied with voltage and which, for example, enables communication with an overall system (not shown) in which the mass flow control system 300 is integrated. For this purpose, the supply interface 369 has an internal data and power interface, via which the connection between the supply interface 369 and the supply module 322 is established when, as shown here, the supply module 322 is plugged into the supply interface 369.The control interface 370 is designed to accommodate the electrical connectors 338 of the supply board 331 and enables the voltage supply of the valve arrangements 325 through the main board 363 as well as the transmission of control signals from the processing unit 368 to the actuator 359 of the valve arrangement 325. This allows the supply board 331 to contain only the high-voltage electronics, and further control of the valve arrangement 325 to take place via the processing unit 368. The control interfaces 370, the supply interface 369 and the first and second pressure sensors 361, 362 are arranged on a top side 372 of the main board 363, with each output channel 309 of the carrier plate 301 being assigned a pair of a first and a second pressure sensor 361, 362.By way of example, the processing unit 368 is also arranged on the top side 372, but can also be arranged on a bottom side 373 of the main board 363 opposite the top side 372 of the main board 363.

[0057] Figure 5 shows a second circuit in which the previously described first circuit is included and in addition the first inlet connection 401 of the second inlet channel 307 is connected to a further fluid source 308. For this circuit, a further channel plate 340 is used which, in addition to the connecting channels 341 and 342, has a further first connecting channel 341 with a further inlet opening 346 and a further second connecting channel 342 with a further outlet opening 347. The fluid mass flow provided by the further fluid source 308 enters the carrier plate 301 via the first inlet connection 401 of the second inlet channel 307, leaves the carrier plate 301 via a further channel opening 345, enters the further first supply channel 341 of the further channel plate 340 via a further inlet connection 346 and is guided via this to a supply connection 326 of a valve arrangement 325.From there, the further fluid mass flow reaches a further outlet channel 309 of the carrier plate 301, as described above, which also contains all the elements required for measuring the fluid mass flow, in particular a further flow resistor 201, a further first pressure sensor 361 and a further second pressure sensor 362, a further sensor opening 364, etc. Since the mass flow control system shown as an example contains a plurality of first pressure sensors 361 and a plurality of second pressure sensors 362, these are each framed by a dashed frame in Figure 2.

[0058] A complete pneumatic circuit of the mass flow control system 300 is shown in Figure 6, wherein the mass flow control system 300 shown as an example has a total of five valve modules 304 (marked by dashed frames), two of which are designed such that they are supplied by both fluid sources 308, but each provide the received fluid mass flow via an outlet channel 309. The three other flow modules 304 each supply two separate outlet channels 309, which are each fluidically connected to only one of the two fluid sources 308, so that only the fluid mass flow of one of the two fluid sources 308 can be provided to a supplier (not shown) via each of these outlet channels 309.

[0059] The first inlet channel 306 and the second inlet channel 307 each comprise a first bore 403 which is formed in the end face 305 of the support plate 301 adjacent to the top side 302 of the support plate 301 and oriented perpendicularly thereto, and a further bore 404 which is fluidly connected to this bore 403 and is formed in a side surface 405 of the support plate 301 adjacent to the top side 302 and the end face 305. The points at which the first bore 403 pierces the end face 305 and the second bore 404 pierces the side surface 405 define the first inlet connection 401 and the second inlet connection 402, respectively. The channel openings 345, which are fluidically connected to the respective first connecting channel 341 of the respective valve module 304 via the inlet connection 346, are in fluid communication with the second bore 404.A blocking element 406 is arranged in each of the first inlet channel 306 and the second inlet channel 307, whereby the first inlet channel 306 and the second inlet channel 307 are each divided into a first inlet channel section 407 and a second inlet channel section 408, wherein the division results in a fluidic separation. By way of example, the first inlet channel section 407 of the first inlet channel 306 and the first inlet channel section 407 of the second inlet channel 307 are each fluidically connected to four channel openings 345, which supply four of the flow modules 304 with the fluid mass flow from one or both fluid sources 308. The second inlet channel section 408 of the first inlet channel 306 or the second inlet channel 307 is each assigned a channel opening 345 which is fluidly connected to the flow module 304 not supplied by the two fluid sources 308.As shown in the figure, the outlet channels 309 assigned to this flow module 304 are connected to a vacuum pump 409, so that this flow module 304 can also be referred to as a vacuum flow module 304. The mass flow control system 300 shown thus has a first fluid circuit, in which a fluid mass flow of a process gas can be supplied to a consumer (not shown) through the two fluid sources 308, and a second fluid circuit which is connected to the vacuum pump 409 and via which a fluid mass flow from a working chamber (not shown) which is connected to the second inlet connection 402 of the first inlet channel 306 and to the second inlet connection 402 of the second inlet channel 307, can be discharged in a controlled manner.

[0060] In this case, the blocking element 406 arranged in the first inlet channel 306 and the second inlet channel 307 in conjunction with the second inlet connections 402 formed in the side surface 405 of the carrier plate 301 ensures that the vacuum flow module 304 is flowed through in the same direction as the other flow modules 304, so that neither the valve arrangements 325 accommodated in the vacuum flow module 304 nor the flow resistance 201 arranged in the associated outlet channels 309 have to be adapted to a changed flow direction when switching from an operation requiring only the first fluid circuit to an operation requiring both fluid circuits by arranging the blocking element 406.

[0061] By way of example, in the assembled state, the main circuit board 363 is received in a circuit board receptacle 375 formed on an underside 374 of the carrier plate 301 and is secured to storage sections 377 by means of fastening elements 376. The circuit board receptacle 375 is delimited by a cover 390 which can be mounted parallel to the underside 374 in grooves 389 formed in the carrier plate 305, as well as by the cover plate 317.

[0062] To seal the first and second pressure sensors 361, 362, two sleeves 378 are provided, which are arranged between the main circuit board 363 and the carrier plate 301 and each have a first sealing groove 379 and a second sealing groove 380 for receiving a first and a second annular sealing element 381, 382. The first sealing groove 379 is designed on the side of the sleeve 378 facing away from the main circuit board 363 in order to receive the first annular sealing element 381, which serves to seal the sleeve 378 from the environment between the sleeve 378 and the second side 365 of the carrier plate 301.The second annular sealing element 382 seals the main board 363 from the output channel 309, wherein the second sealing groove 380 receiving the second annular sealing element 382 is formed in the sleeve 378 such that the second annular sealing element 382 bears against a cylinder section 383 of the respective first and second pressure sensors 361, 362.

[0063] To seal the second inlet channel 367, a drop-shaped sealing element 384 is provided, which is arranged in a sealing recess 383 of the carrier plate 301.

[0064] As can be seen from Figure 7, the valve modules 304 are each connected by a fastening recess

[0065] 385 in the channel plate 340 extending fastening screw

[0066] 386 and by a fastening recess

[0067] 387 in the cover 339 extending fastening screw

[0068] 388 .

[0069] The turbulence throttle 201 arranged in the outlet channel 309 as shown in Figure 8 is shown in more detail in Figure 8. The turbulence throttle 201 is designed as an independent assembly which can be mounted independently of other components of the mass flow control system 300 and tested for its functionality. The turbulence throttle

[0070] 201 comprises a purely exemplary rotationally symmetrical to a central axis 202 and along the central axis

[0071] 202 extended, tubular throttle sleeve 203.

[0072] An outer surface 204 of the throttle sleeve 203 is divided purely by way of example into three sections adjacent to one another along the central axis 202, namely a first guide section 205, a fluid section 206, and a second guide section 207. The first guide section 205 and the second guide section 207 each have an undesignated outer diameter which essentially corresponds to an inner diameter of a throttle section 391 in the outlet channel 309, said throttle section serving to accommodate the turbulence throttle 201. The fluid section 206 arranged between the first guide section 205 and the second guide section 207 has a smaller outer diameter than the two guide sections 205, 207 and forms an annular channel 392 with the throttle section 391 when the turbulence throttle 201 is mounted in the throttle section 391 of the outlet channel 309.

[0073] The second inlet channel 367 opens into this annular channel 391 and is associated with the second pressure sensor 362 shown in more detail in Figure 8.

[0074] A recess 208 of the throttle sleeve 203, which is designed purely as an example to be rotationally symmetrical to 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 larger diameter than the holding section 210. Purely as an example, it is provided that both the inflow section 209 and the outflow section 211 are each designed to be slightly conical, starting from the holding section 210, and widen to an inflow opening 212 or an outflow opening 213.

[0075] In the inflow section 209, a plurality of flow guide elements are arranged, with which the desired turbulence throttling function can be induced when a gaseous fluid flows through the turbulence throttle 201. Starting from the inflow opening 212, an inlet plate 214, a throttle plate 215 directly adjacent to it in the axial direction along the central axis 202 and an outlet plate 216 directly adjacent to the throttle plate 215 in the axial direction along the central axis 202 are provided in the inflow section 209. As can be seen from the illustration in Figure 10, the inlet plate 214 is circular disk-shaped and designed as a plane-parallel plate and has a plurality of inlet bores 217, which are arranged purely by way of example on a common pitch circle 220 at a constant angular pitch to one another.For example, the entry plate 214 can be made from a metal sheet that is provided with the entry holes 217 by a laser cutting process or an etching process. Alternatively, the entry plate can also be made from a plastic material, in particular by a plastic injection molding process.

[0076] It is preferably provided that the inlet plate 214 and the outlet plate 216 are of identical construction.

[0077] The throttle plate 215 has a considerably greater axial extent along the central axis 202 compared to the inlet plate 214 and the outlet plate 216. Functionally, the throttle plate 215 can be divided into a throttle disk 221 and an upstream spacer ring 222 and a downstream spacer ring 223. The throttle disk 221 is circular in shape and has an outer diameter (not designated) that is slightly smaller than an inner diameter (likewise not designated) of the inflow section 209. The throttle disk 221 is provided with precisely one throttle bore 218 that is arranged coaxially to the outer diameter of the throttle disk 221. Purely as an example, the throttle bore 218 is circular in shape.As can be seen from the illustration in Figure 8, the throttle plate 221 has an axial extension along the central axis 202 which corresponds approximately to seven times the axial extension of the inlet plate 214 or the outlet plate 216. On opposite axial end faces 224, 225, circular spacer rings 222, 223 protrude from the throttle plate 221 and serve as axial spacers for the inlet plate 214 or the outlet plate 216. The spacer rings 222 , 223 each have an undesignated inner diameter which is selected such that the inlet bores 217 of the inlet plate 214 and the outlet bores 219 of the outlet plate 216 are not covered .Rather, the spacer rings 222, 223 are provided exclusively for the spaced arrangement of the inlet plate 214 and the outlet plate 216 and have no significant contribution to the throttling effect of the turbulence throttle 201 described in more detail below.

[0078] The task of the holding section 210, which has a slightly smaller inner diameter than the subassembly comprising inlet plate 214, throttle plate 215 and outlet plate 216, is exclusively to provide axial support for this subassembly and also has no significant contribution to the throttling effect of the turbulence throttle 201, which is described in more detail below.

[0079] The outflow section 211 has a substantially identical axial extension along the central axis as the inflow section 209 and serves to calm the fluid flow after passing the flow guide elements described above (inlet plate 214, throttle plate 215, outlet plate 216).

[0080] Furthermore, a radial bore 226 is formed in the outflow section 211, which ensures a fluid communication between the outflow section 211 and the above-described annular channel between the fluid section 206 and the outlet channel 309 and thus enables a fluid pressure prevailing in the outflow section 211 to be tapped for the purpose of differential pressure measurement.

[0081] As can be seen from the illustration in Figure 10, a projection 227 of the throttle bore 218 onto the inlet plate 214 has no overlaps with the inlet bores 217. This ensures that a fluid, in particular a compressed air flow or a process gas flow flowing through the turbulence throttle 201, experiences multiple deflections of its flow direction. This causes the desired turbulent flow in the turbulence throttle 201.The advantage of such a turbulent flow is that the compact design of the turbulence throttle 201 enables a differential pressure measurement in which a pressure value upstream or in front of the turbulence throttle 201, particularly in the region of the inlet opening 212, can be significantly differentiated from a pressure value downstream or after the turbulence throttle 201, particularly at the radial bore 226, thereby enabling a precise differential pressure measurement. From this differential pressure measurement, the fluid mass flow through the turbulence throttle 201 can then be determined with high accuracy.

[0082] As described above, the turbulence throttle 201 is accommodated in the throttle section 391, which for this purpose has an enlarged diameter (not designated) compared to the rest of the outlet channel 309. The throttle section 391 extends from the end face 305 of the support plate 301 against the flow direction into the outlet channel 309, wherein a throttle section base (not designated) which delimits the throttle section 391 at an end facing away from the end face 305 is arranged in the flow direction between the first inlet channel 366 and the second inlet channel 367. As a result of the enlarged diameter, the throttle section base forms a sealing seat (not designated). In the assembled state, a throttle seal 393 is provided between the sealing seat and a throttle end face 228 (Figure 8).To fix the turbulence throttle 201 and to provide a sealing force on the throttle seal 393, a fixing sleeve 394 is arranged between the output coupling 311 and the turbulence throttle 201, which in each case bears against the turbulence throttle 201 and the output coupling 311 with an annular surface not designated.

[0083] The section of the outlet channel 309 located upstream of the flow resistance 201 preferably has a passage section 395 which is fluidly connected to the channel opening 345 and is oriented parallel to the end face 305. The passage section 395 opens at an inlet point 397 into a connecting section 396 of the outlet channel 309, wherein the connecting section 396 is oriented perpendicular to the end face 305 or is formed concentrically to the throttle section 391. In the exemplary embodiment shown, the inlet point 397 of the passage section 395 is formed between and a channel base 398, wherein the channel base 398 delimits the connecting section 396 on its side facing away from the throttle section 391.

[0084] Due to this configuration, there is essentially no or only a very slight fluid flow in the region of the connecting section 396 located between the junction 397 and the channel base 398, so that this region can also be referred to as a dead water chamber 399. For the purpose of measuring the pressure upstream of the turbulence throttle 201 with as little interference as possible, the first sensor opening 364 is formed in the region of the connecting section 396 forming the dead water chamber 399. In this context, "interference-free" means that the measured pressure has no or only a slight dynamic pressure component that can be caused by fluid flow. In an embodiment not shown, the second sensor opening 364 or the first inlet channel 366 of the second sensor opening 364 can also be formed in the region of the connecting section 396 forming the dead water space 399.

Claims

Claims 1. Mass flow control system (300) for the controlled provision of fluid mass flows, comprising a carrier plate (301) which has fluid interfaces on a first side (302) for the attachment of valve modules (304), wherein each fluid interface is provided with a plurality of channel openings (345), wherein each channel opening (345) is connected to an inlet channel (306, 307) formed in the carrier plate (301) or to one of a plurality of outlet channels (309) formed in the carrier plate (301), wherein the inlet channel (306, 307) extends from a first inlet connection (401) through the carrier plate (301) to a second inlet connection (402), wherein a blocking element (406) is arranged in the inlet channel (306, 307), in particular one which can be freely positioned in the inlet channel (306, 307), which blocking element blocks the inlet channel (306, 307) is divided into a first input channel section (407) and a second input channel section (408), which are fluidically separated,wherein the first input channel section (407) is fluidically connected to at least one of the channel openings (345) assigned to the first input channel section (407) and wherein the second input channel section (408) is fluidically connected to at least one of the channel openings (345) assigned to the second input channel section (408), and to a plurality of valve modules (304) each having at least one valve arrangement (325) which are designed to influence at least one fluid mass flow, wherein each of the valve modules (304) has a, having an inlet connection (346) which is sealingly connected to the inlet channel (306, 307) via an associated channel opening (345), and having an outlet connection (347) which is sealingly connected to one of the outlet channels (309) via an associated channel opening (345), having an electronic processing unit (368), having an electrical supply interface (369) and having electrical control interfaces (370) for coupling the valve modules (304), wherein a flow resistance (201) is arranged in each of the outlet channels (309), and wherein each of the outlet channels (309) is assigned sensor openings (364) in the region of the flow resistance (201), which open out on a second side (365) of the carrier plate (301) facing away from the first side (302) of the carrier plate (301), and wherein the sensor openings (364) are associated with pressure sensors (361, 362), wherein the electronic processing unit (368) is electrically connected to the pressure sensors (361,362) and is connected to the supply interface (369) and the control interfaces (370) and is designed for evaluating sensor signals from the pressure sensors (361, 362) and for controlling the valve modules (304) connected to the control interfaces (370) to carry out mass flow control.

2. Mass flow control system according to claim 1, characterized in that the electronic processing unit (368), the electrical supply interface (369), the electrical control interfaces (370) and the pressure sensors (361, 362) are arranged on a main board (363).

3. Mass flow control system according to claim 1 or 2, characterized in that the blocking element (406) is detachably arranged in the inlet channel (306, 307).

4. Mass flow control system according to one of claims 1 to 3, characterized in that a first sensor opening (364) is arranged in the flow direction upstream of the flow resistance (201) and a second sensor opening (364) is arranged in the flow direction downstream of the flow resistance (201), wherein a first pressure sensor (361) assigned to the first sensor opening (364) and a second pressure sensor (362) assigned to the second sensor opening (364) are each designed as absolute pressure sensors, or wherein the first pressure sensor (361) and the second pressure sensor (362) are designed as relative pressure sensors, wherein an ambient pressure sensor for measuring an ambient pressure is provided on the main board (363).

5. Mass flow control system according to one of claims 1 to 3, characterized in that a first sensor opening (364) is arranged in the flow direction upstream of the flow resistance (201) and a second sensor opening (364) has a first inlet channel (366) and a second inlet channel (367), wherein the first inlet channel (366) opens into the outlet channel (309) upstream of the flow resistance (201) in the flow direction and the second inlet channel (367) opens into the outlet channel (309) downstream of the flow resistance (201) in the flow direction, wherein a first pressure sensor (361), which is assigned to the first sensor opening (364), is designed as an absolute pressure sensor and wherein a second pressure sensor (362), which is assigned to the second sensor opening (364),is designed as a differential pressure sensor or wherein the first pressure sensor (361) is designed as a relative pressure sensor and the second pressure sensor (362) is designed as a differential pressure sensor and wherein an ambient pressure sensor for measuring an ambient pressure is provided on the main board.

6. Mass flow control system according to one of the preceding claims, characterized in that the actuator (359) of the valve arrangement (325) is designed as a piezo bender.

7. Mass flow control system according to claim 6, characterized in that the valve module (304) comprises a supply board (331) with high-voltage electronics provided for electrically supplying the actuator (359).

8. Mass flow control system according to one of the preceding claims, characterized in that the processing unit (368) is designed for individual control of each actuator (359).

9. Mass flow control system according to one of the preceding claims, characterized in that the flow resistance (201) is designed as a throttle, in particular as a turbulence throttle.

Images