Description:TECHNICAL FIELD
[0001] The present disclosure generally relates to a flow sensing device for determining a rate of flow of a fluid. In particular, the present disclosure relates to a diaphragm spring based bi-directional fluid flow sensing device for determining a rate of flow of a fluid in a fluid conduit.

BACKGROUND
[0002] The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] In a conduit adapted for flow of liquids, such as oils, fuel, gas, etc., it is important to measure a flow rate of the fluid to determine a volume of the fluid passing through the conduit in a given time duration.
[0004] Some of the typical spring and piston-based flow sensors work on the principle of measuring the displacement of a piston when a flowing fluid pushes the piston by overcoming the force of a spring mounted on the periphery of the piston. The displacement of the piston opens an orifice at the piston head, causing the fluid to flow to the outlet side. Whereas some other spring and piston-based flow sensors work on the principle of measuring the differential pressure of the fluid across an orifice plate when a flowing fluid pushes the piston by overcoming the force of a spring mounted on the periphery of the piston. The displacement of the piston opens an orifice at the piston head, causing the fluid to flow to the outlet side. The fluid flow rate is derived from the differential pressure measurement. These type of flow sensors have following limitations –
• Placement of the meters along the direction of fluid flow results in a large restriction to the fluid flow, so these meters will not be suitable for use in devices like a ventilator where minimal restriction to fluid flow is required.
• These meters may not be responsive to low flow rates due to not being able to overcome the spring force at low flow rates, so these meters will not be suitable for use in devices like a ventilator where measurement of low flow rates is required.
• Digital measurement and feedback of the flow rate is not possible in these meters since the measurement of displacement in the meter is done by the user using a dial gauge with a pointer moving across the scale, so these meters will not be suitable for use in devices like a ventilator where digital measurement and feedback is required.
• Bidirectional measurement of flow rate is typically not possible in these meters, so these meters will not be suitable for use in devices like a ventilator where bidirectional measurement of flow rate is required.
• These flow meters are large and contain many mechanical parts, resulting in low accuracy, bulky design, unreliability, and low life, so these meters will not be suitable for use in devices like a ventilator where these limitations are unacceptable for a meter.
[0005] Most conventional sensors used for determining flow rate of the fluids are expensive and complex, resulting in high cost of maintenance.
[0006] There is, therefore, a requirement in the art for a means to determine fluid flow rate in a conduit that is accurate, and economical.

OBJECTS OF THE PRESENT DISCLOSURE
[0007] An object of the present invention is to provide a flow sensing device to determine a rate of flow of a fluid in a conduit.
[0008] Another object of the present invention is to provide a flow sensing device which is placed in a bypass configuration with respect to the conduit and measures the flow rate of the fluid flowing in the conduit.
[0009] Another object of the present invention is to provide a flow sensing device that enables digital measurement and feedback.
[0010] Another object of the present invention is to provide a flow sensing device that allows bidirectional measurement of flow rate.
[0011] Another object of the present invention is to provide a flow sensing device that is small in size.
[0012] Another object of the present invention is to provide a flow sensing device that has a long life.

SUMMARY
[0013] The present disclosure overcomes one or more shortcomings of the prior art and provides additional advantages discussed throughout the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
[0014] In one non-limiting embodiment of the present disclosure, a flow sensing device for determining a rate of flow of a fluid is disclosed. The flow sensing device comprises a fluid conduit, the fluid conduit includes flow restriction member with a hole adapted to produce a pressure drop when placed in line with fluid flow, and conduit ports. The flow sensing device further comprises a sensor body fluidically configured across the hole for measuring the flow rate of the fluid in the fluid conduit, the sensor body includes a fluid chamber having sensor ports adapted to be connected to conduit ports, a diaphragm spring positioned inside fluid chamber separating the left and right fluid chambers, a shaft affixed to the diaphragm spring, and an electronics housing including a displacement measuring element attached to the shaft adapted to record the displacement of the shaft. An annular groove is present at the end of the shaft and another annular groove is present in the sensor body. The flow sensing device further comprises a processor connected to the displacement measuring element adapted to measure the flow rate of the fluid based on the data provided by displacement measuring element about the recorded displacement of the shaft.
[0015] In one non-limiting embodiment of the present disclosure, wherein an O-ring is placed between the two annular grooves present at the end of the shaft and sensor body, the O-ring is adapted to creates a hermetic sealing between the two sides of the grooves preventing any fluid entrance into the electronics housing. The O-ring further enables the low friction movement of the shaft inside sensor body.
[0016] In one non-limiting embodiment of the present disclosure, wherein a highly elastic sealing membrane is attached to the shaft end between the annular grooves present at the end of the shaft and sensor body, the said sealing membrane is adapted to creates a hermetic sealing between the two sides of the grooves preventing any fluid entrance into the electronics housing. The sealing membrane further facilitates large displacements of the shaft, allowing a large range of flow rate to be measured.
[0017] In one non-limiting embodiment of the present disclosure, wherein the diaphragm spring is made of a single material.
[0018] In one non-limiting embodiment of the present disclosure, wherein the diaphragm spring is made of two different materials. One of the two materials is of high elasticity whereas the another is of low elasticity. The high elasticity of material enables large deflections of the diaphragm spring, allowing a large range of flow rate to be measured. The low elasticity material helps it to impart structural strength and fatigue resistance to high elasticity material at high flow rates and during repeated bi-directional operations.
[0019] In one non-limiting embodiment of the present disclosure, wherein the sensor body enables measurement of flow rate of gas or liquid flowing in the fluid conduit.
[0020] In one non-limiting embodiment of the present disclosure, wherein the diameter of the hole of flow restriction member is fixed.
[0021] In one non-limiting embodiment of the present disclosure, wherein the diameter of the hole of flow restriction member is variable.
[0022] In one non-limiting embodiment of the present disclosure, wherein the displacement measuring element inside the electronics housing is a linear encoder, and wherein the flow sensor enables determination of displacement of the shaft vs flow rate mapping.
[0023] In one non-limiting embodiment of the present disclosure, wherein the displacement measuring element inside the electronics housing is a strain gauge, and wherein the flow sensor enables determination of current vs flow rate mapping.
[0024] In one non-limiting embodiment of the present disclosure, wherein the processor compares the recorded displacement of the shaft or the recorded current with prestored data stored in the memory for measuring the flow rate of the fluid inside the conduit.
[0025] In one non-limiting embodiment of the present disclosure, wherein the output flow rate is processed along with one or more transfer functions stored in memory to arrive at final flow rate of the fluid.
[0026] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF DRAWINGS
[0027] The embodiments of the disclosure itself, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings in which:
[0028] Figure 1 illustrates an exemplary representation of flow sensing device 100 for measuring a flow rate of a fluid, in accordance with an embodiment of the present disclosure;
[0029] Figures 2A and 2B illustrate exemplary representations of flow sensing device 100 and its working cases where the fluid is flowing from left to right, and fluid flowing from right to left respectively, in accordance with an embodiment of the present disclosure;
[0030] Figure 3 illustrates an exemplary representation of flow sensing device 100 for measuring a flow rate of a fluid, in accordance with another embodiment of the present disclosure;
[0031] Figures 4A and 4B illustrate exemplary representations of flow sensing device 100 and its working cases where the fluid is flowing from left to right, and fluid flowing from right to left respectively, in accordance with another embodiment of the present disclosure;
[0032] Figure 5 illustrates an exemplary representation of diaphragm spring 114 made of a single material, in accordance with an embodiment of the present disclosure;
[0033] Figure 6 illustrates an exemplary representation of diaphragm spring 114 made of two different materials, in accordance with another embodiment of the present disclosure; and
[0034] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
[0035] The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure.
[0036] The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying Figures. It is to be expressly understood, however, that each of the Figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
[0037] Disclosed herein is a flow sensing device and method for sensing the rate of fluid flowing inside a fluid conduit. When a fluid flows inside the fluid conduit with a certain flow rate and passes through an annular orifice plate or a variable orifice diaphragm, pressure difference is created across the plate or diaphragm. The amount of pressure difference increases with the increase in the fluid flow rate. The fluid conduit also contains two conduit ports across the orifice plate or diaphragm. The fluid enters the sensor body through sensor ports connected to the conduit ports. An impermeable diaphragm spring is placed in the sensor body, separating the left and right fluid chambers. Due to the pressure difference created in the fluid conduit by the orifice plate or diaphragm, the pressure of the fluid on first side of the plate is more than the pressure of the fluid on the second side of the plate so that the pressure in the first fluid chamber is more than in the second fluid chamber. As a result, the diaphragm spring is deflected. The shaft, which is affixed to the diaphragm also gets displaced, the low friction contacts between the O-ring and the grooves or the membrane facilitates this displacement. The amount of shaft displacement is measured by a linear encoder or strain gauge and the measurement is sent to the processor. The processor then determines the flow rate of the fluid based on the obtained measurement and one or more transfer functions stored in the memory relating the shaft displacement to the flow rate. The transfer functions are pre-determined during the design and testing of the flow sensing device and are preferably such that a large range of flow rate can be measured by just a small range of diaphragm spring deflection and shaft displacement.
[0038] Figure 1 illustrates schematic side view representation of a flow sensing device 100 for measuring a flow rate of a fluid therethrough, in accordance with an embodiment of the present disclosure.
[0039] In one implementation, flow sensing device 100 comprises a fluid conduit 102, a sensor body 108, an electronics housing 120, a processor 124 and a memory 126 (not shown in Figure 1). Those of skilled in the art will appreciate that the above-described components are explained according to one embodiment of the present disclosure, and however, the flow sensing device 100 may comprise additional components as well according to the requirement. The fluid conduit 102 may include a flow restriction member 104 with a hole 104-1, and conduit ports 106-1, 106-2. The sensor body 108 may comprise a fluid chamber 110 having sensor ports 112-1, 112-2. The sensor body may be configured to receive the fluid from the fluid conduit 102 through sensor ports 112-1, 112-2. The sensor body 108 may further comprise a diaphragm spring 114 positioned inside fluid chamber 110 separating the left and right fluid chambers 110-1, 110-2. The sensor body 108 may further comprise a shaft 116 affixed to the diaphragm spring 114. An annular groove 116-1 is present at the end of the shaft and another annular groove 108-1 is present in the sensor body 108. The electronics housing 120 may include a displacement measuring element 122 connected to the shaft 116. The processor 124 may be connected to the displacement measuring element 122 and may be configured to measure the flow rate of the fluid based on the data provided by displacement measuring element 122 about the recorded displacement of the shaft 116. The memory 126 (not shown in Figure 1) may be connected to the processor 124.
[0040] In some embodiments, the sensor body 108 is made by connecting, for example by an interference fit, left and right fluid chambers 110-1, 110-2 as shown in Figure 1. It may be noted that other methods of connecting left and right fluid chambers 110-1, 110-2 are also possible. It is important that any mechanical joint, if present in the sensor body 108, must be free from fluid leakage for the correct working of the flow sensing device 100. The diaphragm spring 114 is clamped at the periphery inside the sensor body 108, separating the left and right fluid chambers 110-1, 110-2. The clamping may be done using any method known in the literature, for example, chemical bonding with an adhesive followed by curing with ultraviolet (UV) light.
[0041] In some embodiments, the fluid conduit 102 and the sensor body 108 are connected through conduit ports 106-1, 106-2 and sensor ports 112-1, 112-2, for example by pneumatic tubes. It may be noted that other methods of connecting fluid conduit 102 and the sensor body 108 are also possible. It is important that any mechanical joint, if present in the between fluid conduit 102 and the sensor body 108, must be free from fluid leakage for the correct working of the flow sensing device 100.
[0042] In some embodiments, an O-ring 118-1 is placed between the two annular grooves 116-1, 108-1 present at the end of the shaft 116 and sensor body 108, the O-ring 118-1 is adapted to create a hermetic sealing between the two sides of the grooves 116-1, 108-1 preventing any fluid entrance into the electronics housing 120. O-ring 118-1 further enables the low friction movement of the shaft 116 inside sensor body 108.
[0043] In some embodiments, the sensor body 108 enables measurement of flow rate of gas or liquid flowing in the fluid conduit 102.
[0044] In some embodiments, the diameter of the hole 104-1 of flow restriction member 104 is fixed.
[0045] In some embodiments, the diameter of the hole 104-1 of flow restriction member 104 is variable.
[0046] In some embodiments, the displacement measuring element 122 inside the electronics housing 120 is a linear encoder, and the flow sensing device 100 enables determination of displacement of the shaft vs flow rate mapping. The linear encoder can be any one of optical linear encoder, magnetic linear encoder, capacitive linear encoder, Inductive linear encoder and eddy current type digital encoder.
[0047] In some embodiments, the displacement measuring element 122 inside the electronics housing 120 is a strain gauge, and wherein flow sensing device 100 enables determination of current vs flow rate mapping.
[0048] In some embodiments, the processor 124 compares the recorded displacement of the shaft 116 or the recorded current with prestored data stored in the memory 126 for measuring the flow rate of the fluid inside the conduit 102.
[0049] In some embodiments, the output flow rate is processed along with one or more transfer functions stored in the memory 126 to arrive at final flow rate of the fluid.
[0050] Figure 2A illustrates schematic side view representation of a flow sensing device 100 and its one of the working cases where the fluid flows in the conduit 102 from left to right at a certain flow rate, in accordance with an embodiment of the present disclosure.
[0051] A fluid flows in the conduit 102 from left to right at a certain flow rate. It enters the sensor ports 112-1, 112-2 from the conduit ports 106-1, 106-2 into the left and right fluid chambers 110-1, 110-2. Due to the pressure difference created in the fluid by the hole 104-1 of flow restriction member 104, the pressure of the fluid on the left side of the flow restriction member 104 is more than the pressure of the fluid on the right side of the flow restriction member 104 so that the pressure in the left fluid chamber 110-1 is more than that of the right fluid chamber 110-2. As a result, the diaphragm spring 114 is deflected towards right. The shaft 116, which is affixed to the diaphragm displaces towards right as well, the low friction contacts between the O-ring 118-1 and the annular grooves 116-1, 108-1 facilitate this displacement. The amount of the displacement of the shaft 116 is measured by displacement measuring element 122 and the measurement is sent to the processor 124. The processor 124 then determines the flow rate of the fluid based on the obtained measurement of the displacement of the shaft 116 and one or more transfer functions stored in the memory 126 relating the displacement of the shaft 116 to the flow rate.
[0052] The inherent nature of the diaphragm spring 114 enables firstly, to maintain a natural state of zero deflection in the absence of a fluid flow in the conduit 102 in any spatial orientation of the flow sensing device 100 and in the presence of small vibrations, and secondly, to quickly attain its natural state of zero deflection upon a sudden change in the fluid flow direction.
[0053] Figure 2B illustrates schematic side view representation of a flow sensing device 100 and its one of the working cases where the fluid flows in the conduit 102 from right to left at a certain flow rate, in accordance with an embodiment of the present disclosure.
[0054] A fluid flows in the conduit 102 from right to left at a certain flow rate. It enters the sensor ports 112-2, 112-1 from the conduit ports 106-2, 106-1 into the right and left fluid chambers 110-2, 110-1. Due to the pressure difference created in the fluid by the hole 104-1 of flow restriction member 104, the pressure of the fluid on the right side of the flow restriction member 104 is more than the pressure of the fluid on the left side of the flow restriction member 104 so that the pressure in the right fluid chamber 110-2 is more than that of the left fluid chamber 110-1. As a result, the diaphragm spring 114 is deflected towards left. The shaft 116, which is affixed to the diaphragm displaces towards left as well, the low friction contacts between the O-ring 118-1 and the annular grooves 116-1, 108-1 facilitate this displacement. The amount of the displacement of the shaft 116 is measured by displacement measuring element 122 and the measurement is sent to the processor 124. The processor 124 then determines the flow rate of the fluid based on the obtained measurement of the displacement of the shaft 116 and one or more transfer functions stored in the memory 126 relating the displacement of the shaft 116 to the flow rate.
[0055] The explanations for the two working cases in Figures 2A and 2B demonstrate the bidirectional flow rate measuring capability of the flow sensing device 100.
[0056] Figure 3 illustrates schematic side view representation of a flow sensing device 100 for measuring a flow rate of a fluid therethrough, in accordance with another embodiment of the present disclosure. A highly elastic sealing membrane 118-2 is attached to the shaft 116 end between the annular grooves 116-1, 108-1 present at the end of the shaft 116 and sensor body 108 in place of O-ring 118-1. The sealing membrane 118-2 is adapted to creates a hermetic sealing between the two sides of the grooves 116-1, 108-1 preventing any fluid entrance into the electronics housing 120. The sealing membrane 118-2 further facilitates large displacements of the shaft 116, allowing a large range of flow rate to be measured.
[0057] Figures 4A and 4B illustrate schematic side view representations of a flow sensing device 100 and its working cases as illustrated in figures 2A and 2B respectively, in accordance with another embodiment of the present disclosure. The explanations of operations of the flow sensing device 100 in Figures 4A and 4B are similar to those of illustrated for figures 2A and 2B respectively. The only difference is that the sealing membrane 118-2 between the annular grooves 116-1, 108-1 facilitates the displacement of the shaft 116.
[0058] In some embodiments, O-ring 118-1 is placed between the two annular grooves 116-1, 108-1 present at the end of the shaft 116 and sensor body 108 as well as a highly elastic sealing membrane 118-2 is also attached to the shaft 116 end between the annular grooves 116-1, 108-1 present at the end of the shaft 116 and sensor body 108.
[0059] Figure 5 illustrates an exemplary representation of diaphragm spring 114 made of a single material, in accordance with an embodiment of the present disclosure. The diaphragm spring 114 is made of a single material. The material may be an elastomer such as:
a. Ethylene Propylene Diene Monomer (EPDM) (Young’s modulus ~ 6 MPa, Tensile strength ~ 18 MPa, Elongation ~ 375%, Hardness ~ 65 Shore A, Density ~ 1430 kg/m^3)
b. Polytetrafluoroethylene (PTFE) (Young’s modulus ~ 575 MPa, Tensile strength ~ 31 MPa, Elongation ~ 450%, Hardness ~ 54 Rockwell, Density ~ 2175 kg/m^3)
c. Ethylene Propylene Rubber (EPR) (Young’s modulus ~ 6 MPa, Tensile strength ~ 18 MPa, Elongation ~ 375%, Hardness ~ 65 Shore A, Density ~ 1430 kg/m^3)
d. Polyurethane (Young’s modulus ~ 6 MPa, Tensile strength ~ 25 MPa, Elongation ~ 375%, Hardness ~ 78 Shore A, Density ~ 1250 kg/m^3)
e. Polybutadiene rubber (BR) (Young’s modulus ~ 2 MPa, Tensile strength ~ 13 MPa, Elongation ~ 300%, Hardness ~ 64 Shore A, Density ~ 950 kg/m^3)
f. Styrene butadiene rubber (SBR) (Young’s modulus ~ 6 MPa, Tensile strength ~ 18 MPa, Elongation ~ 475%, Hardness ~ 68 Shore A, Density ~ 940 kg/m^3)
[0060] Figure 6 illustrates an exemplary representation of diaphragm spring 114 made of two different materials, in accordance with another embodiment of the present disclosure. The diaphragm spring 114 is made of two different materials. One of the two materials is of high elasticity and may be:
a. Ethylene Propylene Diene Monomer (EPDM) (Young’s modulus ~ 6 MPa, Tensile strength ~ 18 MPa, Elongation ~ 375%, Hardness ~ 65 Shore A, Density ~ 1430 kg/m^3)
b. Ethylene Propylene Rubber (EPR) (Young’s modulus ~ 6 MPa, Tensile strength ~ 18 MPa, Elongation ~ 375%, Hardness ~ 65 Shore A, Density ~ 1430 kg/m^3)
c. Polyurethane (Young’s modulus ~ 6 MPa, Tensile strength ~ 25 MPa, Elongation ~ 375%, Hardness ~ 78 Shore A, Density ~ 1250 kg/m^3)
d. Polybutadiene rubber (BR) (Young’s modulus ~ 2 MPa, Tensile strength ~ 13 MPa, Elongation ~ 300%, Hardness ~ 64 Shore A, Density ~ 950 kg/m^3)
e. Styrene butadiene rubber (SBR) (Young’s modulus ~ 6 MPa, Tensile strength ~ 18 MPa, Elongation ~ 475%, Hardness ~ 68 Shore A, Density ~ 940 kg/m^3), etc.
Whereas the another is of low elasticity and may be:
a. Polytetrafluoroethylene (PTFE) (Young’s modulus ~ 575 MPa, Tensile strength ~ 31 MPa, Elongation ~ 450%, Hardness ~ 54 Rockwell, Density ~ 2175 kg/m^3)
The high elasticity of material enables large deflections of the diaphragm spring 114, allowing a large range of flow rate to be measured. The low elasticity material helps it to impart structural strength and fatigue resistance to high elasticity material at high flow rates and during repeated bi-directional operations.
[0061] The processor 124 is configured to determine a rate of flow of the fluid in the fluid conduit 102 based on the transfer functions stored in the memory 126. Thus, the flow sensing device 100 enables measurement of a rate of flow of the fluid through the flow conduit 102. The transfer functions are pre-determined during the design and testing of the flow sensing device 100 and are preferably such that a large range of flow rate can be measured by just a small range of diaphragm spring deflection and shaft displacement. The transfer functions may be dependent on various parameters, for example, the strain gauge's measured current, the linear encoder's measured displacement, temperature, pressure, relative humidity, etc.
[0062] Though, the electronic housing 120 including displacement measuring element 122, and processor 124 have been shown within the sensor body 108 in figures 1 - 4B, the processor 124 may be outside the sensor body 108.
[0063] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.
[0064] When a single device or article is described herein, it will be clear that more than one device/article (whether they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether they cooperate), it will be clear that a single device/article may be used in place of the more than one device or article, or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself.
[0065] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
[0066] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

[0067]
Reference Numerals
Reference Numeral Description
100 Flow sensing device
102 Fluid conduit
104 Flow restriction member
104-1 Hole
106-1, 106-2 Conduit ports
108 Sensor body
108-1, 116-1 Annular grooves
110 Fluid chamber
110-1, 110-2 Left and right fluid chambers
112-1, 112-2 Sensor ports
114 Diaphragm spring
116 Shaft
118-1 O-ring
118-2 Sealing membrane
120 Electronics housing
122 Displacement measuring element
124 Processor
126 Memory

ADVANTAGES OF INVENTION
[0068] The present invention provides a flow sensing device to determine a rate of flow of a fluid in a conduit.
[0069] The present invention provides a flow sensing device which is placed in a bypass configuration with respect to the conduit and measures the flow rate of the fluid in the conduit.
[0070] The present invention provides a flow sensing device that enables digital measurement and feedback.
[0071] The present invention provides a flow sensing device that allows bidirectional measurement of flow rate.
[0072] The present invention provides a flow sensing device that is small in size.
[0073] The present invention provides a flow sensing device that has a long life. , Claims:1. A bi-directional flow sensing device (100) for measuring a flow rate of fluid, the sensing device (100), comprising:
a fluid conduit (102) including a flow restriction member (104) with a hole (104-1) adapted to produce a pressure drop when placed in line with fluid flow, and conduit ports (106-1, 106-2);
a sensor body (108) fluidically configured across the hole (104-1) for measuring the flow rate of the fluid in the fluid conduit (102), the said sensor body (108), comprising:
a fluid chamber (110) having sensor ports (112-1, 112-2) adapted to be connected to conduit ports (106-1, 106-2);
a diaphragm spring (114) positioned inside fluid chamber (110) separating the left and right fluid chambers (110-1, 110-2); and
a shaft (116) affixed to the diaphragm spring (114);
an electronics housing (120) including a displacement measuring element (122) connected to the shaft (116) adapted to record the displacement of the shaft (116);
a processor (124) connected to the displacement measuring element (122) adapted to measure the flow rate of the fluid based on the data provided by displacement measuring element (122) about the recorded displacement of the shaft (116);
memory (126) attached to the processor (124).
2. The sensing device (100) as claimed in claim 1, wherein the sensor body (108) enables measurement of flow rate of gas or liquid flowing in the fluid conduit (102).
3. The sensing device (100) as claimed in claim 1, wherein the diameter of the hole (104-1) is fixed.
4. The sensing device (100) as claimed in claim 1, wherein the diameter of the hole (104-1) is variable.
5. The sensing device (100) as claimed in claim 1, wherein the displacement measuring element (122) is a linear encoder.
6. The sensing device (100) as claimed in claim 5, wherein the linear encoder can be any one of optical linear encoder, magnetic linear encoder, capacitive linear encoder, Inductive linear encoder and eddy current type digital encoder.
7. The sensing device (100) as claimed in claim 6, wherein the sensing device (100) enables determination of displacement of the shaft (116) vs flow rate mapping.
8. The sensing device (100) as claimed in claim 1, wherein the displacement measuring element (122) is a strain gauge.
9. The sensing device (100) as claimed in claim 8, wherein the sensing device (100) enables determination of current vs flow rate mapping.
10. The sensing device (100) as claimed in claim 1, wherein the processor (124) compares the recorded displacement of the shaft (116) or the recorded current with prestored data in the memory (126) for measuring the flow rate of the fluid inside the conduit (102).
11. The sensing device (100) as claimed in claim 1, wherein the output flow rate is processed based on one or more transfer functions stored in the memory (126) to arrive at final flow rate of the fluid.