US-12624976-B1 - Clamp-on thermal meter for non-intrusive flow measurement in a conduit

US12624976B1US 12624976 B1US12624976 B1US 12624976B1US-12624976-B1

Abstract

Compact, non-intrusive thermal flow measurement devices, systems and methods configured to clamp externally onto a pipe, tube, or conduit and quantitatively determine fluid flow without penetrating the conduit or disturbing the internal fluid. Flow rate of fluid includes gas and liquid flows of fluid. The devices, systems and methods include a compact flexible clamp structure housing at least one low-power heater and a plurality of temperature sensors positioned upstream, downstream, and at the heater location along the conduit wall. The conformal clamp enables rapid, one-handed installation on conduits of varying diameters. During operation, the heater raises the pipe wall temperature at the point of measurement, and the flow of fluid induces a directional thermal gradient detected by the sensors. An electronic processor calculates fluid flow rate based on steady-state temperature differences using phase-specific empirical calibrations. The devices, systems and methods accommodate both gas and liquid flows using the same sensor configuration. Additional features include an integrated digital display, wireless communication, and support for portable, battery-powered use. The devices, systems and methods enable precise flow measurement across a range of applications, without pressure drop or fluid access, and supports field deployment, diagnostics, and integration into external monitoring platforms.

Inventors

Michael Kenneth West

Assignees

Advantek Consulting Engineering Inc.

Dates

Publication Date: 20260512
Application Date: 20250610

Claims (19)

1 . A non-intrusive thermal flow measurement device for quantitatively determining fluid flow in a conduit, comprising: a flexible clamp structure configured to externally conform to and maintain continuous circumferential thermal contact with conduits of varying diameters without requiring interchangeable inserts; at least one heater configured to provide a heat flux of approximately 10 Watts per square inch to approximately 20 Watts per square inch, the heater configured to externally heat only a portion of a conduit wall at a measurement location, without directly heating bulk fluid inside the conduit wall, thereby avoiding vaporization and enabling portable, battery-powered operation; a plurality of temperature sensors positioned along the conduit wall and configured to measure temperature differentials between multiple distinct points along the conduit wall; and an electronic processor configured to calculate and determine a fluid flow rate in the conduit based on steady-state temperature differentials which are the temperature differentials measured by said sensors when the temperature differentials have reached a steady-state within a time of approximately 3 minutes to approximately 15 minutes.
2 . The device of claim 1 , wherein the flexible clamp structure comprises two half-shells configured to flexibly adapt and snugly conform to conduit diameters between a range between approximately ¼ inch to approximately ⅝ inch.
3 . The device of claim 1 , wherein the plurality of temperature sensors includes at least one sensor positioned upstream of the heater, at least one sensor positioned directly on the heater, and at least one sensor positioned downstream of the heater.
4 . The device of claim 1 , further comprising a communication medium configured to transmit measured temperature and flow rate data through a wired connection.
5 . The device of claim 1 , further comprising a communication medium configured to transmit measured temperature and flow rate data through at least one wireless connection selected, from the group consisting of Bluetooth, Wi-Fi Direct, NFC, Zigbee, and Z-Wave.
6 . The device of claim 1 , further comprising: a digital display integrated directly into the clamp structure, configured to locally display measured temperatures and calculated fluid flow rates without requiring an external meter.
7 . The device of claim 1 , wherein the calculation of the fluid flow rate is performed empirically from said steady-state temperature differentials by using calibration constants specific to fluid phases, thereby enabling the determination of a fluid flow of either a gas or a liquid in the conduit using same sensor configuration.
8 . The device of claim 2 , wherein for an approximately ¼″ pipe, the time frame is within approximately 3 minutes.
9 . The device of claim 2 , wherein for an approximately ⅜″ pipe, the time frame is within approximately 6 minutes.
10 . The device of claim 2 , wherein for an approximately ⅝″ pipe, the time frame is within approximately 15 minutes.
11 . The device of claim 2 , wherein overall weight of the device is up to approximately 1 pound or approximately 454 grams, overall length of the device is up to approximately 7.6″ or approximately 193 millimeters, and overall width of the device is up to approximately 1.7″ or approximately 43 millimeters.
12 . The device of claim 2 , wherein spacing between adjacent sensors is up to approximately 1.5 inches or 38 millimeters.
13 . The device of claim 2 , wherein an upper half-shell of the two half-shells, includes: an upper flexible pad pliable support between the upper half-shell and an upper half heater temperature sensor, and an upper half heater pad between the upper half heater temperature sensor and an upper half heater element, and wherein a lower half-shell of the two half shells includes a lower flexible pad pliable support between the lower half-shell and lower half-heater temperature sensor, and a lower half heater pad between the lower half heater temperature sensor and a lower half heater pad between the lower half heater temperature sensor and a lower half heater element.
14 . The device of claim 1 , wherein the flexible clamp structure includes: an upper arm having a grip end and a distal end with a concave lower surface; a lower arm having a grip end and a distal end with a concave upper surface; a spring-loaded member for allowing the upper arm to pivot relative to the lower arm, wherein the concave lower surface on the distal end of the upper arm and the concave upper surface on the distal end of the lower arm grip about a conduit wall.
15 . The device of claim 1 , wherein the flexible clamp structure includes a fixed mechanical clamp assembly that includes: an upper shell having a lower facing concave surface; and a lower shell having an upper facing concave surface, wherein the upper shell and the lower shell wrap about a section of the conduit wall.
16 . The device of claim 15 , wherein the fixed mechanical clamp assembly includes: fasteners selected from at least one of screws and bolts for locking the upper shell to the lower shell.
17 . The device of claim 16 , wherein the fixed mechanical clamp assembly includes: securing members selected from at least one of: magnets, latches, ties, spring clips, and latch clamps for securing the upper shell to the lower shell.
18 . A non-intrusive thermal flow measurement device for quantitatively determining fluid flow in a conduit, comprising: a flexible clamp structure configured to externally conform to and maintain continuous circumferential thermal contact with conduits of varying diameters without requiring interchangeable inserts, the flexible clamp structure comprises two half-shells configured to flexibly adapt and snugly conform to conduit diameters between a range between approximately ¼ inch to approximately ⅝ inch, wherein the flexible clamp structure includes an upper arm having a grip end and a distal end with a concave lower surface, and a lower arm having a grip end and a distal end with a concave upper surface, and a spring loaded member for allowing the upper arm to pivot relative to the lower arm, wherein the concave lower surface on the distal end of the upper arm and the concave upper surface on the distal end of the lower arm grip about conduit wall; at least one heater configured to provide a heat flux of approximately 10 Watts per square inch to approximately 20 Watts per square inch, the heater configured to externally heat only a portion of the conduit wall at a measurement location, without directly heating the bulk fluid inside the conduit wall, thereby avoiding vaporization and enabling portable, battery-powered operation; a plurality of temperature sensors positioned along the conduit wall and configured to measure temperature differentials at distinct points along the conduit wall, the plurality of temperature sensors includes at least one sensor positioned upstream of the heater, at least one sensor positioned directly on the heater, and at least one sensor positioned downstream of the heater, wherein spacing between adjacent sensors is approximately 1.5 inches or 38 millimeters; wherein an upper half-shell of the two half-shells, includes: an upper flexible pad pliable support between the upper half-shell and an upper half heater temperature sensor, and an upper half heater pad between the upper half heater temperature sensor and an upper half heater element, and wherein a lower half-shell of the two half shells includes; a lower flexible pad pliable support between the lower half-shell and lower half-heater temperature sensor, and a lower half heater pad between the lower half heater temperature sensor and a lower half heater element: and an electronic processor configured to calculate and determine a fluid flow rate in the conduit based on steady-state temperature differentials which are the temperature differentials measured by said sensors when the temperature differentials have reached a steady state within a time frame of approximately 3 minutes to approximately 15 minutes, wherein overall weight of the device is up to approximately 1 pound or approximately 454 grams, overall width of the device is approximately 1.7 inches or approximately 43 millimeters, and overall length of the device is approximately 7.6 inches or approximately 193 millimeters.
19 . A non-intrusive thermal flow measurement device for quantitatively determining fluid flow in a conduit, comprising: a flexible clamp structure configured to externally conform to and maintain continuous circumferential thermal contact with conduits of varying diameters without requiring interchangeable inserts, the flexible clamp structure comprises two half-shells configured to flexibly adapt and snugly conform to conduit diameters between a range between approximately ¼ inch to approximately ⅝ inch, wherein the flexible clamp structure includes a fixed mechanical clamp assembly with an upper shell having a lower facing concave surface, and a lower shell having an upper facing concave surface, wherein the upper shell and the lower shell wrap about a section of the conduit wall, the fixed clamp assembly is assembled by either fasteners selected from at least one of screws and bolts for locking the upper shell to the lower shell, or is assembled by securing members selected from at least one of: magnets, latches, ties, spring clips, and latch clamps for securing the upper shell to the lower shell; at least one heater configured to provide a heat flux of approximately 10 Watts per square inch to approximately 20 Watts per square inch, the at least one heater configured to externally heat only a portion of a conduit wall at a measurement location, without directly heating the bulk fluid inside the conduit, thereby avoiding vaporization and enabling portable, battery-powered operation; a plurality of temperature sensors positioned along the conduit wall and configured to measure temperature differential between distinct points, the plurality of temperature sensors includes at least one sensor positioned upstream of the heater, at least one sensor positioned directly on the heater, and at least one sensor positioned downstream of the heater, wherein spacing between adjacent sensors is approximately 1.5 inches or approximately 38 millimeters; wherein an upper half-shell of the two half-shells, includes: an upper flexible pad pliable support between the upper half-shell and an upper half heater temperature sensor, and an upper half heater pad between the upper half heater temperature sensor and an upper half heater element; wherein a lower half-shell of the two half shells includes: a lower flexible pad pliable support between the lower half-shell and lower half-heater temperature sensor, and a lower half heater pad between the lower half heater temperature sensor and a lower half heater element; and an electronic processor configured to calculate and determine a flow rate in the conduit based on steady-state temperature differentials which are the temperature differentials measured by said sensors when the temperature differentials have reached a steady-state within a time frame of approximately 3 minutes to approximately 15 minutes, wherein overall weight of the device is up to approximately 1 pound or approximately 454 grams, overall width of the device is approximately 1.7 inches or approximately 43 millimeters, and overall length of the device is approximately 7.6 inches or approximately 193 millimeters.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a Continuation-In-Part of U.S. patent application Ser. No. 17/869,288 filed Jul. 20, 2022, which is a Continuation-In-Part of U.S. application Ser. No. 17/079,009 filed Oct. 23, 2020, now abandoned. The entire disclosure of each of the applications listed in this paragraph are incorporated herein by specific reference thereto. FIELD OF INVENTION This invention relates generally to flow meters for measuring fluid flow, that includes liquid and gas flow, and in particular to systems, devices and methods for sensing the flow rate of fluid in a pipe, tube or conduit, without physically penetrating the pipe or conduit wall to directly contact the fluid within the pipe or conduit, by clamping about the pipe, tube or conduit by measuring data from heater elements and temperature sensing elements that are in half sensor shells that clamp about the exterior of pipes, tubes and conduits of any cross section shape. BACKGROUND AND PRIOR ART Fluid flow through pipes, tubes, and conduits encompasses both liquid and gas phases. Accurate measurement of such flow is critical in many applications, including refrigeration, semiconductor and pharmaceutical manufacturing, automotive fuel systems, and aerospace hydraulic systems. In these and other fields, accurate real-time flow data is essential for testing, process control, diagnostics, or product measurement and verification. Portability, compactness, and non-intrusiveness are highly desirable due to cost, space, and practicality-particularly in systems where fluid access is limited, such as inside equipment enclosures, or where fluid flow cannot be interrupted. The present invention addresses these critical needs. Most conventional flow sensors require insertion into the conduit, permanent in-line installation, or rerouting of fluid through the measurement device. These configurations are often intrusive and require system shutdown, depressurization, or fluid evacuation to install, particularly in closed systems like refrigeration circuits. Three known non-intrusive alternatives; transit-time ultrasonic, Doppler, and Coriolis flow meters avoid pipe penetration, but they are often bulky, exceedingly expensive, complex to set up, calibrate and use, or ineffective for some fluids and tubing sizes. Other known flow sensors are not compact, portable, self-contained or robust; and as a consequence of these shortcomings, known flow sensors cannot meet many critical needs. The fundamental thermal flow sensing method is a well-established concept. A heater is positioned between two temperature sensors, upstream and downstream. The flow of a fluid past the temperature sensors and the heater element will tend to heat the downstream flowing fluid. The heater raises the fluid temperature differential, which is influenced by the flow velocity. The relationship between temperature difference and flow rate can be mathematically modeled. Some devices alternatively monitor the energy input required to maintain a constant heater temperature, which also relates to flow rate. However, nearly all thermal flow sensors known in the art require fluid to flow directly through the sensor body, making them intrusive by design. This prevents use in systems where breaking the line for installation of the sensor is impractical, unsafe, or costly. Insertion creates limitations when applied to sealed, pressurized systems like chillers or refrigeration equipment, where refrigerant must be evacuated to allow sensor installation, and corrosive fluids, such as acetone or hypochlorous acid, can damage thermal flow sensor components, rendering insertion impractical. In operation, known thermal sensors often require high energy to create large temperature gradients. This creates problems when measuring high-density or high-specific-heat fluids such as water, glycol, and liquid refrigerants, or volatile or flammable liquids such as solvents and hydrocarbon fuels. High thermal input risks vaporizing the fluid, creating measurement error and safety concerns. These constraints strictly limit the practical use of prior art thermal flow sensors. Simpler thermal devices used in leak detection, such as residential water or gas pipe alarms, also employ temperature sensors and/or heaters clamped externally onto pipes. These systems are designed to detect only a binary state: flow or no flow. They lack the resolution and methodology to calculate quantitative mass flow, and they are not portable or readily reusable across multiple systems. Clearly unaddressed by prior art is a compact, clamp-on, self-contained thermal flow measurement device capable of accurately quantifying both gas and liquid flow without penetration of the conduit. Further, while the same sensor configuration may be used to measure either gas or liquid flow, the empirical flow equations and calibration constants differ for each phase. Known references do not teach or suggest the use of externally