• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    12 ABSTRACT A flow meter for measuring a fluid flow comprising a first flow sensor, a second flowsensor, a flow direction sensor and switching means. The first flow sensor isarranged to generate a first signal being representative of a rate of said fluid flow in afirst flow direction. The second flow sensor is arranged to generate a second signalrepresentative of a rate of said fluid flow in a second flow direction, where the secondflow direction is opposite the first flow direction. The flow direction sensor is arrangedto indicate the direction of the fluid flow. The switching means is arranged tocooperate with the flows sensors and the flow direction sensor, and is configured toconnect the first flow sensor to provide said first signal as an output signal when theflow direction sensor indicates said first flow direction, and to connect the second flowsensor to provide said second signal as said output signal when the flow direction sensor indicates said second flow direction. (Fig. 1)
    公开号:SE538430C2
    申请号:SE1550165
    申请日:2015-02-16
    公开日:2016-06-21
    发明作者:Göran Bahrton
    申请人:Göran Bahrton；
    IPC主号:
    专利说明:

    FLOW METER Field of the inventionThe invention relates to the field of flow meters for measuring a fluid flow in for example a pipe or conduit.
    Background Flow meters for accurately measuring a flow rate of a fluid are known in the art. Oneexample of such a flow meter is disclosed in US4167873 which describes a flowmeter of the fluidistor-oscillator type. Another type of flow meter which is primarilyused to measure gas flow is thermal mass flow sensors measuring the temperature difference between a heated and non-heated temperature sensor.
    A problem with these known flow meters is that they may only measure flows in onedirection. ln certain applications, it is however necessary to measure fluids which flowin different direction. ln for example large compressed air circuits comprising severalcompressors, the direction of the air flow may rapidly change depending on theinstantaneous input and output of compressed air at various positions in the circuit.Thus, there is a long-felt need for a flow meter which allows measurement of fluid flows independent of flow direction.
    SummaryAn object of the present invention is to provide a flow meter which is able to measure fluid flows flowing in both directions through for example a pipe, conduit or channel.
    These and other objects are achieved by the present invention by means of a flowmeter according to the independent claim. Preferred embodiments are defined in the dependent claims.
    According to the invention, there is provided a flow meter for measuring a fluid flow,flowing through for example a pipe, conduit or channel. The flow meter comprises afirst flow sensor, a second flow sensor, a flow direction sensor and switching means.The first flow sensor is arranged to generate a first signal being representative of arate of said fluid flow in a first flow direction. The second flow sensor is arranged to generate a second signal representative of a rate of said fluid flow in a second flowdirection, where the second flow direction is opposite the first flow direction. The flowdirection sensor is arranged to indicate, or provide an indication of, the direction ofthe fluid flow. The switching means is arranged to cooperate with the flows sensorsand the flow direction sensor, and is configured to connect the first flow sensor toprovide said first signal as an output signal when the flow direction sensor indicatessaid first flow direction, and to connect the second flow sensor to provide said secondsignal as said output signal when the flow direction sensor indicates said second flowdirection.
    Put differently, the invention may be described according to the following. First andsecond flow sensors are arranged in or in fluid communication with a pipe, conduit orchannel through which the fluid flows. Each flow sensor is arranged to generate oroutput a signal being representative or corresponding of a rate of said fluid flowsolely in one flow direction, wherein the flow sensors are arranged in oppositedirections such that the first flow sensor measures the flow in a first flow direction,and generates or outputs a first signal corresponding thereto, and the second flowsensor measures the flow in a second flow direction, and generates or outputs asecond signal corresponding thereto. The flow direction sensor is arranged tomeasure or detect the direction of the fluid flow in the pipe, conduit or channel, andmay generate or output a direction signal representative or corresponding to saiddirection. The flow sensors and the flow direction sensor are electrically connected orcoupled to the switching means. The switching means is configured to connect, routeor switch the first signal from the first flow sensor to an output of the flow meter (asan output signal) if a direction signal is received which corresponds to the first flowdirection. Analogously, the switching means is configured to connect, route or switchthe second signal from the second flow sensor to an output of the flow meter (as anoutput signal) if a direction signal is received which corresponds to the second flowdirection.
    The invention is based on the insight that a bi-directional flow meter for accuratelymeasuring a fluid flow may be achieved by combining two flow sensors arranged tomeasure the flow rate in opposite directions with a flow direction sensor which allowsthe correct flow sensor to provide the output signal. lt is understood that the term fluid comprises liquids and gases. lt is also understoodthat flow sensor describes a device for measuring a mass or volume flow rate of thefluid in the sense that an electrical signal representative or corresponding to the massor volume flow rate of the fluid is generated or outputted. The flow sensors mayinclude signal processing means to convert or process the generated electrical signalinto an appropriate signal which may be directly proportional to the measuredquantity. Othervvise, the signal processing means may be provided separately, e.g.the flow meter comprises an additional signal processing component which convertsor processes the first and/or second electrical signal from the flow sensors or theoutput signal into an appropriate signal, or alternatively, the first and second signalsare provided directly as output signals, and any signal processing, if necessary, maybe performed separately from the flow meter.
    According to an embodiment of the invention, the flow meter further comprises a pipeor conduit arranged to allow at least a portion of the fluid flow to pass there through.A flow restriction is arranged to restrict the at least portion of the flow passing throughthe pipe or conduit. The flow restriction may be arranged in the pipe or conduit, forexample in the form of a restriction plate. Alternatively, the flow restriction may beformed integrally with the pipe or conduit, or may be formed by the pipe or conduititself, i.e. the flow restriction results from the flow resistance of a portion of, or thewhole, pipe or conduit, which depends on for example the dimensions and/orcurvature of the pipe or conduit. ln embodiments, the whole or essentially the wholefluid flow may pass through the pipe or conduit of the flow meter. ln embodiments,the flow sensors, the flow restriction and the flow direction sensor are arranged as asingle integrated unit.
    The flow direction sensor may comprise a channel, an indicating element and aposition sensor, where the channel has first and second opposite ends arranged influid communication with the conduit at flow wise opposite sides of said flowrestriction, respectively. ln other words, one of the first or second ends (depending onthe flow direction) may be in fluid communication with the conduit upstream of theflow restriction, and the other end may be in fluid communication with the conduitdownstream of the flow direction. The indicating element may be arranged in the channel and be reciprocally movable between the ends in response to the fluid flowin the direction of the fluid flow. The position sensor may be arranged to indicatewhen the indicating element has reached first and second predetermined positionscorresponding to the first flow direction and said second flow direction, respectively.The first and second predetermined positions may be the first and second endpositions, i.e. when the indicating element is at the first and second ends,respectively. The position sensor may be arranged to generate or output a directionsignal representative or corresponding to the flow direction. This is an advantageousembodiment since it provides a robust and reliable flow direction sensor of simple design.
    The indicating element may advantageously be a hollow spherical body, e.g. a hollowball. This is advantageous since such an indicating element quickly and with littleforce moves from one end to the other allowing measurement of flow with rapidlychanging flow direction. The position sensor may comprise at least one inductivesensor located in cooperative relationship with the indicating element. This isadvantageous since it allows detection of the position of the indicating elementwithout physical contact therewith, thus providing an even more robust and reliable SenSOF.
    Alternatively, the flow direction sensor may comprise a pressure difference sensorarranged in fluid communication with the conduit at flow wise opposite sides of theflow restriction, respectively, to generate or output a direction signal representative orcorresponding to the flow direction, for example a positive pressure difference signalwhen the fluid flows in the first flow direction, and a negative pressure differencesignal when the fluid flows in the second flow direction. This is an advantageous embodiment since it provides a robust and reliable flow direction sensor.
    According to an embodiment of the invention, the first and second flow sensors arearranged in series or in parallel to form a flow sensor arrangement which is arrangedin parallel with said flow restriction such that a first sub flow of said fluid flow passesthrough said flow restriction and a second sub flow of said fluid flow passes throughsaid first and second flow sensors. Thus, the flow is divided into a (main) first subflow through the flow restriction and an (auxiliary) second sub flow through the flow sensor arrangement, wherein the first sub flow is normally substantially greater thanthe second sub flow. The second sub flow only has to be of such size that the flow sensors are able to measure the flow. ln the embodiment where the first and second flow sensors are arranged in series,the flow meter advantageously further comprises a first check valve arranged inparallel with the first flow sensor and in a direction to bypass the first flow sensorwhen said fluid flows in the second flow direction, and a second check valvearranged in parallel with the second flow sensor and in a direction to bypass thesecond flow sensor when the fluid flows in the first flow direction. This isadvantageous since the pressure drop over the flow sensor arrangement may bereduced.
    The flow sensors may be of the fluidistor oscillator type. ln other embodiments, theflow sensors are thermal mass flow sensors, which may be arranged in the pipe or conduit.
    Brief description of the drawingsThese and other aspects of the present invention will now be described in more detailwith reference to the appended drawings, which show presently preferredembodiments of the invention, wherein: fig. 1 shows a schematic illustration of a flow meter according to a firstembodiment of the invention, fig. 2 shows a schematic illustration of a flow meter according to a secondembodiment of the invention, fig. 3 shows a schematic illustration of a flow meter according to a thirdembodiment of the invention, and fig. 4 shows a schematic illustration of a flow meter according to a fourth embodiment of the invention.
    Detailed description Figure 1 shows a schematic illustration of a flow meter 1 according to a firstembodiment of the invention. The flow meter 1 is arranged to measure a fluid flowF1, F2 flowing through a pipe or conduit 5. The flow meter comprises a first flowsensor 2a, a second flow sensor 2b, a flow direction sensor 3 and switching means 4.
    The flow sensors 2a, 2b and the direction sensor 3 are arranged in the pipe orconduit 5. ln other embodiments, the flow sensors and/or the direction sensor may bearranged outside the pipe or conduit, but in fluid communication there with. The firstflow sensor 2a is arranged to generate a first signal S1 being representative of a rateof the fluid flow in a first flow direction F1. The second flow sensor is arranged togenerate a second signal S2 representative of a rate of the fluid flow in a second flowdirection F2. The first flow sensor 2a may not generate any signal at all when the fluidflows in the second direction F2, or may alternatively not generate any relevantoutput. The second flow sensor 2b may not generate any signal at all when the fluidflows in the first direction F1, or may alternatively not generate any relevant output.As can be seen in the figure, the second flow direction F2 is opposite the first flowdirection F1. The flow direction sensor 3 is arranged to indicate or detect thedirection of the fluid flow by outputting a direction signal representative orcorresponding to the flow direction, which direction signal is communicated to theswitching means. The switching means 4 is a relay which is arranged to connect thefirst flow sensor 2a to provide said first signal S1 as an output signal S when the flowdirection sensor provides a direction signal which indicates the first flow direction F1(as shown in the figure), and to connect the second flow sensor 2b to provide thesecond signal S2 as said output signal S when the flow direction sensor provides adirection signal which indicating the second flow direction F2.
    Figure 2 shows a schematic illustration of a flow meter 11 according to a secondembodiment of the invention which is similar to the first embodiment except for adifferent type of direction sensor 13, and in that it further comprises a flow restriction16. The flow restriction 16 is a restriction plate arranged in the pipe or conduit 15 torestrict the fluid flow in both flow directions F1, F2. The direction sensor 13 isarranged outside the pipe or conduit 15, but in fluid communication therewith. Theflow sensors 12a, 12b are arranged in the pipe or conduit 15, but may in otherembodiments be arranged outside the pipe or conduit in fluid communication therewith.
    The flow direction sensor 13 comprises a channel 17, an indicating element 18 and aposition sensor 19. The channel 17 has first and second opposite ends arranged influid communication with the conduit via connecting channels 17a, 17b at flow wise opposite sides of said flow restriction 16, respectively. The indicating element 18,which is a hollow ball, is arranged in the channel 17 and is reciprocally movablebetween the ends in response to the fluid flow in the direction of the fluid flow. As canbe seen in the figure, the fluid flow in direction F1 causes a fluid flow from the pipe orconduit 15 to the channel 17 via the connecting channel 17b, which causes theindicating element to move to the left in the figure in the same direction F1 of the flowuntil it approaches the first end of the channel 17. Vice versa, when the fluid flows inthe direction of F2, the fluid flow causes a fluid flow from the pipe or conduit 15 to thechannel 17 via the connecting channel 17a, which causes the indicating element tomove to the right in the figure in the same direction F2 of the flow until it approachesthe second end of the channel 17. The position sensor 19, which is an inductivesensor is arranged to indicate which of the first and second ends the indicatingelement has reached by outputting a direction signal which is connected to theswitching means. Thus, when the indicating element is at the first end of the channel17 (as shown in the figure), the position sensor outputs a direction signal indicatingthe first flow direction F1, and when the indicating element is at the second end of thechannel 17, the position sensor outputs a direction signal indicating the second flowdirection F2.The switching means 14 operates in the same way as described above with reference to figure 1.
    Figure 3 shows a schematic illustration of a flow meter 21 according to a thirdembodiment of the invention which is similar to the second embodiment, mainlydiffering in a different type of flow sensors 22a, 22b. The flow restriction 26 is arestriction plate arranged in the pipe or conduit 25 to restrict the fluid flow in both flowdirections F1, F2. The flow sensors 22a, 22b and the direction sensor 23 arearranged outside the pipe or conduit 25, but in fluid communication therewith. The flow sensors are of the fluidistor oscillator type.
    The flow direction sensor 23 comprises a channel 27, an indicating element 28, aposition sensor 29, and connecting channels 27a, 27b. The above description of theflow direction sensor, with reference to figure 2, applies also to the flow directionsensor 23 of this third embodiment, except for that the connecting channels extendthrough the whole flow direction sensor. This allows the flow sensors 22a, 22b to beconnected to the pipe or conduit 25 via the flow direction sensor. The first and second flow sensors 22a, 22b are connected in series via connecting element 210 toform a flow sensor arrangement which in turn is arranged in parallel with the flowdirection sensor 23 and the flow restriction 26. Due to the pressure difference overthe flow restriction 26, the fluid flow is divided into a (main) first sub flow through theflow restriction 26 and an (auxiliary) second sub flow through the flow directionsensor 23, the flow sensors 22a, 22b and the connecting element 210. As can beseen from the figure, the flow sensors, the flow direction sensor and the connectingelement are arranged as a single unit, which may also comprise the pipe or conduit25 and the flow restriction 26. The switching means 24 operates in the same way as described above with reference to figures 1 and 2.
    Figure 4 shows a schematic illustration of a flow meter according to a fourthembodiment which comprises all features of the above described third embodiment,and further comprises a first check valve 311a arranged in parallel with the first flowsensor 32a and in a direction to bypass the first flow sensor when said fluid flows inthe second flow direction F2, and a second check valve 311b arranged in parallelwith the second flow sensor 32b and in a direction to bypass the second flow sensorwhen the fluid flows in the first flow direction F1 (as illustrated in the figure).
    The description above and the appended drawings are to be considered as non-limiting examples of the invention. The person skilled in the art realizes that severalchanges and modifications may be made within the scope of the invention. Forexample, the switching means may be any type of device achieving the desiredfunction, such as an electronic control unit. Further, the flow direction sensor may bea pressure difference sensor rather than the inductive position sensor describedabove with reference to figures 2-4. The scope of protection is determined by the appended patent claims.
    权利要求:
    Claims (12)
    [1] 1. _ Flow meter (1) for measuring a fluid flow (F1, F2), said device comprising: - a first flow sensor (2a) arranged to generate a first signal (S1) beingrepresentative of a rate of said fluid flow in a first flow direction (F1); - a second flow sensor (2b) arranged to generate a second signal (S2)representative of a rate of said fluid flow in a second flow direction (F2), saidsecond flow direction being opposite said first flow direction; - a flow direction sensor (3) arranged to indicate the direction of the fluid flow;and - switching means (4) arranged to cooperate with the flow sensors and theflow direction sensor, and being configured to connect the first flow sensor toprovide said first signal as an output signal (S) when the flow direction sensorindicates said first flow direction, and to connect the second flow sensor toprovide said second signal as said output signal when the flow direction sensor indicates said second flow direction. _ Flow meter according to claim 1, further comprising - a conduit (15) arranged to allow at least a portion of said fluid flow to passthere through; - a flow restriction (16) arranged to restrict said at least portion of said flow;and wherein said flow direction sensor (13) comprises: - a channel (17) having first and second opposite ends arranged in fluidcommunication with said conduit (15) at flow wise opposite sides of said flowrestriction (16); - an indicating element (18) arranged in said channel and being reciprocallymovable in response to said fluid flow; and - a position sensor (19) arranged to indicate when said indicating element (18)has reached first and second predetermined positions corresponding to saidfirst flow direction and said second flow direction, respectively. _ Flow meter according to claim 2, wherein said first and second flow sensors (22a, 22b) are arranged in series to form a flow sensor arrangement which isarranged in parallel with said flow restriction (26) such that a first sub flow of said fluid flow passes through said flow restriction and a second sub flow ofsaid fluid flow passes through said first and second flow sensors. _ Flow meter according to claim 2, wherein said first and second flow sensors are arranged in parallel to form a flow sensor arrangement which is arrangedin parallel with said flow restriction such that a first sub flow of said fluid flowpasses through said flow restriction and a second sub flow of said fluid flowpasses through said first and second flow sensors. _ Flow meter according to claim 3, further comprising - a first check valve (311a) arranged in parallel with said first flow sensor (32a)and in a direction to bypass said first flow sensor when said fluid flows in saidsecond flow direction, and - a second check valve (31 1 b) arranged in parallel with said second flowsensor (32b) and in a direction to bypass said second flow sensor when saidfluid flows in said first flow direction. _ Flow meter according to any one of the claims 2-5, wherein said indicating element (18; 28) is a hollow spherical body. _ Flow meter according to any one of the claims 2-6, wherein said position sensor comprises at least one inductive sensor (19; 29) located in cooperative relationship with said indicating element (18; 28). _ Flow meter according to any one of the preceding claims, wherein said flow sensors (22a-b) are of the fluidistor oscillator type. _ Flow meter according to any one of the claims 1-7, wherein said flow sensors (2a-b; 12a-b) are thermal mass flow sensors. 10. Flow meter according to claim 9 as dependent on claim 2, wherein said flow sensors (2a-b; 12a-b) are arranged in said conduit. 11 1 1 .Flow meter according to any one of the preceding claims as dependent onclaim 2, wherein said flow sensors, said flow restriction and said flow direction sensor are arranged as a single unit. 12. Flow meter according to any one of the preceding claims as dependent onclaim 2, wherein said flow restriction (16) is arranged in said pipe or conduit.
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    同族专利:
    公开号 | 公开日
    SE1550165A1|2016-06-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2017-10-03| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE1550165A|SE1550165A1|2015-02-16|2015-02-16|Flow meter for measuring fluid flow in two directions|SE1550165A| SE1550165A1|2015-02-16|2015-02-16|Flow meter for measuring fluid flow in two directions|
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