Fluid flow control device

Abstract

A fluid flow control device is described. The apparatus includes a set of at least two control valves, each valve having a first port, a second port, and a third port, and an actuator configured to switch the control valves between a first state in which the first port is in fluid communication with the second port, and a second state in which the first port is in fluid communication with the third port. The first port is in fluid communication with the third port. The apparatus further comprises a controller arranged to control the actuators of the control valves such that, at a given time, one of the at least two control valves is selected to be in a first state and the remaining of the at least two control valves is in a second state.

Description

Technical Field

[0001] The present invention relates to a fluid flow control device and a method for controlling fluid flow, and in particular to a device and a method for controlling the flow of fluid (eg, gas) from multiple sources. Background Art

[0002] For low biogas flow conditions (such as those nearing the completion of biochemical methane potential (BMP) testing), automated analysis of methane (CH4) and carbon dioxide (CO2) components is challenging due to the small volume of fluid released from the reactor and the high precision required for measurement. For example, the volume of fluid flowing out of a reactor may be less than 7ml. This fluid must be transported to the sensor through a fluid channel that may have a volume of several milliliters. It is also necessary to use a single probe or sensor to measure multiple channels while ensuring that carryover from previous readings is not counted and taking into account the effect of increased back pressure on the calibration values ​​of existing volume displacement units. In addition, if necessary, a system designed to handle small volume fluid flow and composition analysis may also need to maintain the ability to measure other important gas components of interest (such as H2S). Further, it is generally desirable to implement such a system at a low cost. Summary of the Invention

[0003] According to a first aspect of the present invention, there is provided a fluid flow control device, comprising: a set of at least two control valves, each valve having a first port, a second port, and a third port; and an actuator configured to switch the control valve between a first state and a second state, wherein in the first state, the first port is in fluid communication with the second port, and in the second state, the first port is in fluid communication with the third port. The fluid flow control device further comprises a controller arranged to control the actuators of the control valves such that, at a given time, one of the at least two control valves is selected to be in the first state, and the remaining of the at least two control valves is in the second state.

[0004] Thus, the controller can control the flow of fluids (e.g., gases) from multiple sources, for example, to a manifold, where the second port can be connected to a corresponding port on the manifold. This can allow fluid from one of the multiple sources to be measured, while any fluid from the remaining sources is exhausted to the outside of the device. Exhausting the remaining fluid sources may reduce the pressure in the fluid delivery channels of the device, thereby improving measurement accuracy.

[0005] In the first state, the third port can be closed. In the second state, the second port can be closed.

[0006] Only one of the at least two control valves may be selected to be in the first state.

[0007] The apparatus may include a manifold having a plurality of inlet ports and an outlet port, wherein each second port is fluidly connected to a respective inlet port.

[0008] A one-way valve may be provided between each second port of the control valve and the corresponding inlet port of the manifold to prevent fluid from flowing from the inlet port of the manifold to the corresponding second port of the control valve.

[0009] The apparatus may further comprise a sensor, wherein the outlet port of the manifold is connected to the sensor.

[0010] In the second state, the third port may be fluidly connected to the vent.

[0011] That is, when the control valve is in the second state, fluid may be released from the control valve.

[0012] The sensor may be a fluid flow sensor. The sensor may be a substance sensor, such as a methane sensor or a carbon dioxide sensor.

[0013] A one-way valve may be provided between the outlet port of the manifold and the sensor, which may allow fluid to flow only from the outlet port of the manifold to the sensor and may prevent fluid from flowing from the sensor to the outlet port.

[0014] The actuator may be an electromechanical actuator. For example, the electromechanical actuator may be a solenoid. The control valve may be a solenoid-controlled valve.

[0015] At least two of the control valves may be zero-pressure valves. This may reduce the pressure in a channel conveying a fluid in the device, thereby improving the measurement accuracy of the system or device.

[0016] The first and second states of at least two of the control valves may be stable states. At least two of the control valves may be bistable. That is, the control valves may remain in the first or second state without continuous or intermittent power. At least two of the control valves may be latching valves.

[0017] The controller may be a microcontroller. The controller may be operably connected to one or more relay modules. Each relay module may control the state of one or more control valves of the at least two control valves, for example by controlling their corresponding actuators.

[0018] The controller may be arranged to receive a signal from one or each mass flow sensor in a set of two or more mass flow sensors, each mass flow sensor corresponding to a respective control valve.

[0019] The mass flow sensor may be a tumbler mass flow sensor, and the signal may indicate that the tumbler has tumbled, released gas, and is in a new stable state. Thus, the controller receives a signal from the mass flow sensor indicating that fluid is to be received at the first port of a corresponding one of the set of two or more control valves.

[0020] The controller, upon receiving the signal from the mass flow sensor, may be configured to send a signal to the actuator of the corresponding control valve to place the corresponding control valve in the first state.

[0021] The controller may be configured to send signals to the remaining actuators (i.e., actuators corresponding to the mass flow sensor that sensed the signal) to place their corresponding control valves (i.e., those control valves not corresponding to the mass flow sensor that received the signal) in the second state.

[0022] The first port can be connected to a gas source. For example, the gas source can be a bottle, a tank, or a reactor. The reactor can be an anaerobic reactor.

[0023] According to a second aspect of the present invention, a method is provided, comprising: placing a first actuator of a plurality of actuators in a first state; and placing the remaining actuators of the actuators in a second state. Each actuator is configured to switch a control valve between the first state and the second state, each valve having a first port, a second port, and a third port, wherein in the first state, the first port is in fluid communication with the second port, and in the second state, the first port is in fluid communication with the third port, and each second port is connectable to a corresponding inlet port of a manifold.

[0024] The step of placing the actuator in the first state or the second state includes sending a signal to the actuator, and the signal may be received from a mass flow sensor.

[0025] The signal designating the first state and the second state and the operation of placing the control valve in the first state and the second state may be performed simultaneously.

[0026] The method may further include measuring a property of any fluid released from the second port of the control valve in the first state. The property may be, for example, volume or composition. For example, if the fluid is a gas, the presence or concentration of methane or carbon dioxide may be measured.

[0027] According to a third aspect of the present invention, there is provided a computer program comprising instructions which, when executed by one or more processors, cause the one or more processors to perform the method according to the second aspect.

[0028] According to a fourth aspect of the present invention, there is provided a computer program product comprising a computer readable medium storing the computer program according to the third aspect.

[0029] According to a fifth aspect of the present invention, there is provided a module, the module being configured to execute the method according to the second aspect. The module may be a hardware module.

[0030] According to a sixth aspect of the present invention, there is provided a monolithic integrated circuit comprising: a processor subsystem comprising at least one processor and a memory; and a module according to the fifth aspect of the present invention.

[0031] According to a seventh aspect of the present invention, there is provided a system comprising: an apparatus according to the first aspect; and an integrated circuit according to the sixth aspect, the integrated circuit being arranged to control the apparatus.

[0032] The integrated circuit may be a digital integrated circuit. The integrated circuit may include memory. The memory may be volatile memory, such as DRAM or SRAM. The memory may be non-volatile memory, such as EPROM, EEPROM, NOR flash memory, or NAND flash memory. The integrated circuit may be a microintegrated circuit, such as a microprocessor, a microcontroller, or a signal processing chip. The integrated circuit may be a microcontroller with embedded flash memory. The integrated circuit may be a processor without embedded flash memory. The integrated circuit may be a system on chip (SoC). The integrated circuit may be a logic integrated circuit, such as an application-specific integrated circuit chip, standard logic, or a display driver. The integrated circuit may be a fixed logic integrated circuit. The integrated circuit may include a field programmable gate array (FPGA).

[0033] The device may further include a connection module, for example, a wireless connection module or a local area network connection module, such as a Bluetooth module, a WiFi module, etc. The connection module may be configured to retrieve data from a server (such as a cloud server). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Certain embodiments of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0035] Figure 1 is a schematic block diagram of an apparatus for controlling fluid flow;

[0036] Figure 2 is a schematic block diagram of an apparatus for controlling fluid flow;

[0037] Figure 3 is a schematic block diagram of an apparatus for controlling fluid flow;

[0038] Figure 4is a schematic block diagram of a fluid flow path of a fluid flow measurement device;

[0039] Figure 5 A first multi-channel manifold is illustrated;

[0040] Figure 6 is a vertical cross-sectional view of eight mass flow sensors and their connection to a perspective view of multiple bioreactors;

[0041] Figure 7 illustrates a top view of a second multi-channel manifold;

[0042] Figure 8 illustrates a side view of a second multi-channel manifold;

[0043] Figure 9 illustrates a bottom view of a second multi-channel manifold;

[0044] Figure 10 illustrates a vertical cross-sectional view of a second multi-channel manifold;

[0045] Figure 11 illustrates a perspective view of a second multi-channel manifold;

[0046] Figure 12 illustrates a perspective view of a second multi-channel manifold;

[0047] Figure 13 illustrates a bottom view of a second multi-channel manifold;

[0048] Figure 14 illustrates a top view of a second multi-channel manifold;

[0049] Figure 15 illustrates a vertical cross-sectional view of a second multi-channel manifold;

[0050] Figure 16 illustrates a first side view of a second multi-channel manifold;

[0051] Figure 17 illustrates a second side view of a second multi-channel manifold;

[0052] Figure 18 illustrates a first horizontal cross-sectional view of a second multi-channel manifold;

[0053] Figure 19 illustrates a second horizontal cross-sectional view of a second multi-channel manifold;

[0054] Figure 20 illustrates a third horizontal cross-sectional view of a second multi-channel manifold; and

[0055] Figure 21 is a flow chart of a method of operating a fluid flow measurement device. DETAILED DESCRIPTION

[0056] refer to Figure 1 , shows a system 1 for measuring the volume or composition of a fluid.

[0057] System 1 can be used for residual biogas potential (RBP) and biochemical methane potential (BMP) testing.

[0058] The system 1 comprises a controller 2 (eg a microcontroller) and one or more actuators 31, 32, 33, 34, ... 3 n The actuator 3 may be an electromechanical actuator, such as a solenoid valve, a hydraulic or a pneumatic actuator. Each actuator 3 is arranged to control a corresponding control valve 41, 42, 43, 44, ... 4 n Each actuator 3 can operate more than one control valve 4. The control valve 4 can be a zero-pressure valve, such as a zero-pressure solenoid valve or a zero-pressure latching valve. This can have the effect of reducing the pressure in the channel conveying the fluid in the device, which can improve the measurement accuracy of the system 1 or device.

[0059] The actuator 3 may be controlled via a relay driver 5 that includes one or more relay modules 6 for relaying signals from the controller 2 to the one or more actuators 4. The relay driver 5 may include a second controller 7 that may receive signals from the first controller 2 and send signals to control each of the one or more relay modules 6.

[0060] The first controller 2 (also referred to as "controller") may include a processor 8 (e.g., a central processing unit (CPU) or a graphics processing unit (GPU)), a sensor reader 9, a wireless controller 10 (e.g., a Bluetooth or WiFi controller), a memory 11 (e.g., dynamic random access memory (DRAM) and static random access memory (SRAM)), and data storage 12, which may be in the form of non-volatile memory, such as NVRAM.

[0061] The first controller 2 can be operably connected to one or more sensors 15, such as a methane (CH4) sensor, a carbon dioxide (CO2) sensor, and a flow sensor. The first controller 2 is connected to an interface 16 via a wireless controller 10. The interface 16 can be a local area network (LAN) computer that can display data from the sensors in real time or near real time. The data from the sensors 15 can be downloaded to the interface 16 (e.g., a computer) for further processing. The sensors 15 can also be connected to the controller 2 via the wireless controller 10. The controller 2 and the sensors 15 can be connected via a suitable cable. The controller 2 may also include a clock (not shown) and a level converter (not shown).

[0062] refer to Figure 2, shows a second example system 12. In the second system 12, the wireless controller 10, the memory 11, the data storage 12, the clock 17 and the level converter 18 can be modules separate from the controller 2 and operatively connected to the microprocessor 2.

[0063] The controller 2 may be operatively connected to one or more flow sensors 19 , such as mass flow sensors, and configured to receive signals from the flow sensors 19 .

[0064] refer to Figure 3 , the controller 2 is connected to four relay modules 61, 62, 63, 64, each relay module 6 is connected to four actuators 3, and each actuator 3 controls one control valve 4. Therefore, in this example, one controller 2 can control sixteen control valves 4. Additional relays 6, actuators 3, and control valves 4 can be added to appropriate controllers 2.

[0065] refer to Figure 4 Each control valve 4 is a three-way control valve having a first port 21, a second port 22, and a third port 23. The control valve 4 can be switched between a first state and a second state. In the first state, the first port 21 is in fluid communication with the second port 22, and in the second state, the first port 21 is in fluid communication with the third port 23. For clarity, Figure 4 In the figure, only the first control valve 41 is labeled with the first port 211, the second port 221, and the third port 231. The control valve 4 can be bi-stable; for example, the first and second states of the control valve 4 can be stable. That is, the control valve 4 can remain in the first or second state without continuous or occasional power supply. The control valve 4 can be a latching or locking valve, such as the LHL series control solenoid valve, such as the LHLA1221411H, which is a three-way latching valve.

[0066] The control valve 4 can be a magnetic latch-controlled solenoid valve. The control valve can be an ultra-low power valve, for example, with a power consumption as low as 5.5 mJ per switching. The control valve 4 can also have low heat dissipation. If the control valve 4 is a latching valve, moving the valve from one state to another (i.e., latching movement) may require only a momentary current pulse to switch to each flow state and maintain it in that state. When the control valve 4 remains in a specific flow state for an extended period of time, it may consume no power, generate no heat, or produce no noise.

[0067] Each first port 21 is connected to a corresponding fluid source 25, such as a gas source. The fluid source 25 can be a reactor, such as a bioreactor that releases gas from a biological reaction. The gas released from the bioreactor can include methane (CH4) and carbon dioxide (CO2). Multiple fluid sources 25 can be present in a fluid source unit 26 (e.g., a static batch reactor system). If the fluid source is a bioreactor, such as a bioreactor bottle containing a fluid (e.g., digestate), each fluid source 25 can also include a corresponding agitator (not shown) or "stirring device". The agitator stirs the digestate to make it uniform.

[0068] The fluid from each fluid source 25 then enters a corresponding flow sensor 19. The fluid flow sensors can take any suitable form; for example, they can be differential pressure flow sensors or thermal mass flow sensors. If the fluid is a gas, each flow sensor 19 can take the form of a gas tumbler having a housing containing a pivoting trapezoidal block and partially filled with water. When the gas enters the tumbler, it is trapped beneath the block, which is initially in a resting position. A certain volume of gas begins to accumulate and begins to lift one side of the block. This continues until a large enough volume of gas has accumulated to tilt the block enough to allow that volume of gas to escape. The block returns to its resting position (i.e., it flips over), and the process is then repeated. The volume of gas required to cause the block to tip over is known, and by counting each time the block tips over (e.g., using a magnet and a reed switch attached to the block), the total volume of gas can be calculated.

[0069] The fluid flow sensor 19 may be mounted in a single block 29 .

[0070] Each second port 22 is connected to a corresponding inlet 31 of a multichannel manifold 32. The multichannel manifold 32 can have any number of inlets, for example, eight or sixteen inlets. The multichannel manifold has an outlet 33 through which fluid from one of the inlets flows out of the multichannel manifold 32. Optionally, a one-way valve 34 can be present between the second port 22 and the inlet 31 of the multichannel manifold 32 to prevent fluid from flowing from the multichannel manifold 32 to the control valve 4.

[0071] The third port 33 is connected to the first vent 35. For example, if the fluid is a gas, the vent can be in fluid communication with the atmosphere surrounding the system. Alternatively, the vent can be connected to a collection bag (not shown) or other fluid waste storage. A one-way valve (not shown) can also be connected to the third port 23 to prevent fluid from entering the valve 3 through the vent 35.

[0072] Outlet 33 is connected to at least one sensor 15, such as a methane (CH4) or carbon dioxide (CO2) sensor. Optionally, a one-way valve 36 may be present between outlet 33 and first sensor 15. At least one sensor 15 is connected to a second vent 37, and optionally, a one-way valve 38 may be connected between second vent 37 and at least one sensor 15 to prevent fluid from the vent from flowing into sensor 15. Second vent 37 has a similar function to first vent 35 and may have a similar structure.

[0073] Reference again Figures 1 to 4 Controller 2 is configured to receive a signal from a mass flow sensor 19 (e.g., a signal from one mass flow sensor 19 in a set of two or more mass flow sensors 19). Each mass flow sensor 19 may correspond to a corresponding control valve 4. When mass flow sensor 19 is a tumbler mass flow sensor 19, the signal from the mass flow sensor may indicate that the tumbler has tumbled, released gas, and is in a new stable state. Therefore, controller 2 receives a signal from mass flow sensor 19 indicating that fluid is to be received at first port 21 of one of the control valves 4 in the set. Upon receiving the signal from mass flow sensor 19, controller 2 sends a signal to actuator 3 of the corresponding control valve 4 (e.g., via relay driver 5 and relay module 6) to place the corresponding control valve 4 in a first state—i.e., first port 21 is in fluid communication with second port 22, and third port 23 is not in fluid communication with either first port 21 or second port 22. Consequently, the corresponding gas source 25 from which the signal originates is fluidly connected to manifold 32 and sensor 15. The controller 2 also sends signals to the remaining control valves 4 that do not correspond to the mass flow sensors 19 that received the signal, so as to place these remaining control valves 4 in the second state—that is, the first port 21 is in fluid communication with the third port 23, and the second port 22 is not in fluid communication with either the first port 21 or the third port 23. Therefore, the gas from the remaining gas sources 25 is exhausted to the outside of the device or system 1. In this way, the controller 2 can control the flow of fluid (e.g., gas) from multiple sources 25 to, for example, the manifold 32 (e.g., a multi-channel manifold 32), and can allow the gas from one gas source 25 to be measured, while exhausting the gas from other gas sources 25.

[0074] For example, gas is released from the third fluid source 253 into the third flow sensor 193, causing the third flow sensor to flip and send a signal to the controller 2. The controller 2 sends a signal to the third actuator 33 (e.g., via the first relay module 61) to place the third control valve 43 in the first state, and simultaneously to all other actuators 31, 32, 34, 35, 36, ... 3 nSend signals to their respective control valves 41, 42, 44, 45, 46...4 n This allows the measurement of the fluid from the third fluid source 253, while the fluid from the remaining sources 251, 252, 254, 255, ... 25 n Any fluid in the remaining fluid source 25 is exhausted to the outside of the device 1. Exhausting the fluid in the remaining fluid source 25, rather than closing the valve and retaining gas in the device or system, may reduce the pressure in the fluid delivery channel of the device 1, thereby potentially improving measurement accuracy.

[0075] Optionally, if the system is to be used with gas, a desiccant 38 may be placed between the gas source 25 and the sensor 15. The desiccant 38 may be, for example, a bottle filled with silica gel or another suitable desiccant, or a gas drying bottle. The desiccant can reduce the humidity of the gas before it reaches the sensor 15, extending the life of the sensor 15 and potentially improving the accuracy of the sensor 15.

[0076] refer to Figure 5 , the multi-channel manifold 32 may be in the form of a disk, with the outlet 33 located at the center of the disk and the inlet 31 surrounding the circumference of the multi-channel manifold 32 .

[0077] refer to Figure 6 , the fluid source unit 26 in the form of a bioreactor system includes several bioreactor bottles as gas sources 25. The agitator 40 stirs the fluid in the bioreactor bottles to keep the fluid uniform. The gas from each bioreactor bottle (e.g., fluid source 25) then flows to and enters the corresponding flow sensor 19 in the fluid flow block 29. Still referring to Figure 6 The gas flow measurement device block 29 as previously described receives gas from the bioreactor bottles, with eight individual gas flow sensors 19. Each flow sensor 19 receives gas from a corresponding bioreactor gas source 25.

[0078] refer to Figure 7 , a top view of a circular or disc-shaped multi-channel manifold 32 shows sixteen actuators 3 attached around the circumference of the manifold 32. Each actuator 3 has a respective inlet 31 and a respective vent 34 arranged on a line between the actuator 3 on the circumference and the center of the manifold 32. In this example, the vent 34 is closer to the center of the manifold 32 than the inlet 31.

[0079] refer to Figure 8 , showing Figure 73. Here, a single outlet 33 can be seen, centered at the bottom of the manifold 32. Outlet 33 is where fluid exits the manifold 32, optionally via a one-way valve 34, and enters the sensor 15. The side view also illustrates the location of the control valves 4 adjacent to their respective actuators 3.

[0080] refer to Figure 9 , shows a bottom view of the manifold 32. The outlet 33 is located in the center of the manifold 32. The control valves 4 are located around the circumference of the manifold 32 adjacent to (or "under") their respective actuators (not shown).

[0081] refer to Figure 10 , Figure 7 The cross section of the mid-manifold shows the first port 21, the second port 22, and the third port 33 of the control valve 4. A first passage 41 connects the inlet to the first port 21. A second passage 42 connects the second port 22 to the outlet 33. A third passage 43 connects the third port 23 to the vent 35. The first and second passages 41, 42 may constitute at least a portion of the flow path in the first state. The first and third passages 41, 43 may constitute at least a portion of the flow path in the second state.

[0082] refer to Figure 11 , shows a perspective view of a multi-channel manifold 32 having sixteen actuators 3 , control valves 4 , inlets 31 and vents 35 .

[0083] refer to Figure 12 , showing Figure 7 3, without the actuator 3, control valve 4, or connectors for the inlet 33 and vent 35. The ends of the first, second, and third channels 41, 42, 43 are shown at the circumference of the manifold 32, connecting to the first, second, and third ports 21, 22, 23, respectively.

[0084] refer to Figure 13 , showing Figure 12 FIG. 3 is a bottom view of the manifold 32 in FIG. 4 , showing the outlet 33 located in the center of the manifold 32 .

[0085] refer to Figure 14 , showing Figure 12 FIG3 is a top view of the manifold 32 in FIG3 , which illustrates the locations of the sixteen inlets 31 and their corresponding vents 35. Each inlet 31 and vent 35 may have an M6 threaded hole for securing a suitable connector.

[0086] refer to Figure 15 , Figure 14Section DD of the middle manifold 32 shows the first channel 41, the second channel 42, and the third channel 43 in the cross section. The third channel is in fluid communication with the outlet 33. The diameters of the first channel 41, the second channel 42, and the third channel 43 can be made as small as possible so that the volume of the channel is very small. For example, the diameters of the first channel 41, the second channel 42, and the third channel 43 can be between 1 mm and 3 mm (e.g., 1.5 mm, 1.6 mm, 1.98 mm, 2 mm, 2.5 mm) to minimize the volume of the channels 41, 42, and 43. Minimizing the volume of the fluid flow channel can ensure that the amount of gas remaining in the previous gas measurement is minimized, and thus the accuracy of the gas measurement can be improved. The first port 21, the second port 22, and the third port 23 can have the same diameter range as the first channel 41, the second channel 42, and the third channel 43, or the same diameter value.

[0087] refer to Figure 16 , showing Figure 12 32. The ends of the first, second, and third channels 41, 42, 43 can be seen at the circumference of the manifold 32.

[0088] refer to Figure 17 , showing Figure 12 A side view of the manifold 32 in FIG. 1 is shown, indicating sections AA, BB and CC. Figure 18 , showing Figure 12 Section AA of FIG. 3 shows sixteen third channels 43 in fluid communication with the outlet 33. Figure 19 , section BB shows sixteen second channels 42. Figure 20 , section CC shows a portion of sixteen first channels 41 and sixteen second channels 42 .

[0089] refer to Figure 21 To operate the system 1, the controller 2 optionally receives a signal from the mass flow sensor 19 (step S1). Upon receiving the signal, the controller 2 sends a signal to the corresponding actuator 3 to place the actuator 3 in a first state, and sends a signal to the remaining actuators 3 to place them in a second state (step S2). Optionally, a property (e.g., volume) or the presence or concentration of a substance is measured (step S3).

[0090] The signals can be sent simultaneously so that the actuators 3 are in the desired states simultaneously. As described above, when the actuator is in the first state, it puts the corresponding control valve 4 in the first state, and when the actuator is in the second state, it puts the corresponding control valve 4 in the second state.

[0091] Revise

[0092] It will be appreciated that various modifications may be made to the embodiments described above. Such modifications may involve equivalent and other features known in the design, manufacture, and use of gas measurement devices, systems, and components thereof, and may be used instead of or in addition to features already described herein. Features of one embodiment may be substituted for or supplemented by features of another embodiment.

[0093] Although the claims in this application have been expressed as specific combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel feature or any novel combination of features disclosed herein, whether explicitly or implicitly, or any generalization thereof, whether or not it relates to the same invention as currently claimed in any claim, and whether or not it alleviates any or all of the same technical problems as the present invention. The applicant hereby declares that new claims may be formulated for these features and / or combinations of these features during the prosecution of this application or any subsequent application derived therefrom.

Claims

1. A fluid flow control device, comprising: a set of at least two control valves, each valve having a first port, a second port, and a third port, and an actuator configured to switch the control valve between a first state and a second state, wherein in the first state the first port is in fluid communication with the second port, and in the second state the first port is in fluid communication with the third port; as well as A controller is arranged to control the actuators of the control valves such that at a given time, one of the at least two control valves is selected to be in the first state and the remaining of the at least two control valves is in the second state.

2. The apparatus according to claim 1, further comprising: A manifold having a plurality of inlet ports and an outlet port, wherein each second port is fluidly connected to a respective inlet port.

3. The apparatus according to claim 2, further comprising: A sensor, wherein the outlet port of the manifold is connected to a sensor.

4. The device according to any one of claims 1 to 3, wherein In the second state, the third port is fluidly connected to the vent.

5. The device according to any one of claims 1 to 4, wherein The actuator is an electromechanical actuator.

6. The device according to any one of claims 1 to 5, wherein: The at least two control valves are zero-pressure valves.

7. The device according to any one of claims 1 to 6, wherein: The first state and the second state of the at least two control valves are stable states.

8. The device according to any one of claims 1 to 7, wherein The at least two control valves are latching valves.

9. The device according to any one of claims 1 to 8, wherein The controller is a microcontroller.

10. The device according to any one of claims 1 to 9, wherein The controller is arranged to receive a signal from one of a set of two or more mass flow sensors, each mass flow sensor corresponding to a respective control valve.

11. The device according to claim 10, wherein The controller, upon receiving a signal from the mass flow sensor, is configured to send a signal to an actuator of the corresponding control valve to place the corresponding control valve in the first state.

12. The device according to any one of claims 1 to 11, wherein The first port is connectable to a gas source.

13. A method comprising: placing a first actuator of the plurality of actuators in a first state; placing the remaining actuators in the plurality of actuators in a second state, Each actuator is configured to switch a control valve between the first state and the second state, each valve having a first port, a second port, and a third port, wherein in the first state, the first port is in fluid communication with the second port, and in the second state, the first port is in fluid communication with the third port, each second port being connectable to a respective inlet port of the manifold.

14. The method according to claim 13, further comprising: A property of any fluid released from the second port of the control valve in the first state is measured.

15. The method according to claim 13 or 14, wherein: The property is volume.

16. A computer program comprising instructions which, when executed by one or more processors, cause the one or more processors to perform the method according to any one of claims 13 to 15.

17. A computer program product comprising a computer readable medium storing the computer program according to claim 16.

18. A module configured to perform the method according to any one of claims 13 to 15.

19. A monolithic integrated circuit, comprising: a processor subsystem comprising at least one processor and a memory; as well as The module according to claim 18.

20. A system comprising: The device according to any one of claims 1 to 12; as well as An integrated circuit as claimed in claim 19, arranged to control the device.

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