Methods and apparatus for fluid flow measurement
A fluid flow meter estimates the velocity of water or another fluid flowing through pipe by comparing measurements of the water velocity to one or more pre-determined templates. The fluid flow meter may collect measurement signals from one or more flow sensors (e.g., ultrasonic transducers), estimate the fluid velocity or flow rate by comparing the measurement signals to the template(s), and either store the comparison results in local memory, transmit the results to a remote memory or server, or both. In some embodiments, the fluid flow meter transmits the results to a server via a wireless interface (e.g., a Zigbee, Bluetooth, or Wi-fi interface). The transducers and processing system can be powered by a battery, a power line, or, for manifolds installed outdoors, a solar cell. Example transducers and processing systems may also have a passive wake-up feature for power reduction; that is, they may only draw power when water or another fluid flows through the pipe.
1. A fluid flow meter to measure a velocity of a fluid flowing through a lumen, the fluid flow meter comprising:
a hinged housing to fit about a structure defining the lumen;
a sensor, disposed within the hinged housing, to provide a measurement signal representative of the velocity, the sensor comprising:
(i) a first transducer to transmit an ultrasonic signal through the fluid flowing through the lumen;
(ii) a second transducer to receive a reflected, scattered, or transmitted copy of the ultrasonic signal; and
(iii) a front end to produce the measurement signal from the reflected, scattered, or transmitted copy of the ultrasonic signal;
a memory to store a template associated with a possible velocity of the fluid;
a processor, communicatively coupled to the sensor and to the memory, to perform a comparison of the measurement signal to the template and to determine an estimated velocity of the fluid based on the comparison; and
a communications interface, communicatively coupled to the processor, to transmit a representation of at least one of the estimated velocity and the measurement signal to a server, the server comprising an analytics engine to determine fluid usage information based on the at least one of the estimated velocity and the measurement signal and to provide the fluid usage information to a user or a third party via a wireless device.
2. The fluid flow meter of claim 1 wherein the hinged housing comprises a locking interface to enable tool-less, clamp-on installation of the fluid flow meter.
3. The fluid flow meter of claim 1 wherein:
the ultrasonic signal is a first ultrasonic signal,
the second transducer is further configured to transmit a second ultrasonic signal through the fluid flowing through the lumen,
the first transducer is configured to receive a reflected, scattered, or transmitted copy of the second ultrasonic signal, and
the front end is further configured to produce the measurement signal based on a difference of the reflected, scattered, or transmitted copy of the first ultrasonic signal and the reflected, scattered, or transmitted copy of the second ultrasonic signal.
4. The fluid flow meter of claim 1 wherein the memory stores a plurality of templates, each template in the plurality of templates corresponding to a different possible velocity of the fluid flowing through the lumen, and wherein
the processor is further configured to compare the measurement signal to each template in the plurality of templates.
5. The fluid flow meter of claim 1 wherein the template is produced at a first sampling frequency, sampled at a second sampling frequency lower than the first sampling frequency, and stored in the memory.
6. The fluid flow meter of claim 1 wherein the processor is further configured to interpolate at least one of the measurement signal and the template before or while performing the comparison.
7. The fluid flow meter of claim 1 wherein the processor is further configured to add a first random waveform to the measurement signal and a second random waveform to the template before performing the comparison.
8. The fluid flow meter of claim 1 wherein the processor is further configured to detect a change in the diameter of the lumen and to report the change via the communications interface.
9. A method of estimating a velocity of a fluid flowing through a lumen, the method comprising:
transmitting an ultrasonic signal through the fluid flowing through the lumen;
receiving a reflected, scattered, or transmitted copy of the ultrasonic signal; and
producing a measurement signal representative of the velocity of the fluid flowing through the lumen from the reflected, scattered, or transmitted copy of the ultrasonic signal;
performing a comparison of the measurement signal to a template associated with a possible velocity of the fluid;
determining an estimated velocity of the fluid based on the comparison;
transmitting, to a server, a representation of at least one of the estimated velocity and the measurement signal;
determining fluid usage information based on the at least one of the estimated velocity and the measurement signal; and
transmitting the fluid usage information from the server to a wireless device.
10. The method of claim 9 wherein the ultrasonic signal is a first ultrasonic signal, and further comprising:
transmitting the first ultrasonic signal in a first direction through the fluid flowing through the lumen;
transmitting a second ultrasonic signal in a second direction through the fluid;
receiving a reflected, scattered, or transmitted copy of the second ultrasonic signal; and
producing the measurement signal from a difference between the reflected, scattered, or transmitted copy of the first ultrasonic signal and the reflected, scattered, or transmitted copy of the second ultrasonic signal.
11. The method of claim 9 further comprising:
generating the template at a first sampling frequency; and
sampling the template at a second sampling frequency lower than the first sampling frequency.
12. The method of claim 9 further comprising, before performing the comparison of the measurement signal to the template:
adding a first random waveform to the measurement signal; and
adding a second random waveform to the template.
13. The method of claim 9 wherein performing the comparison of the measurement signal to the template comprises:
comparing the measurement signal to each of a plurality of templates, wherein each template in the plurality of templates is associated with a different possible velocity of the fluid.
14. The method of claim 9 wherein performing the comparison of the measurement signal to the template comprises:
interpolating at least one of the measurement signal and the template.
15. A system for monitoring fluid usage, the system comprising:
(a) at least one fluid flow meter comprising:
(i) a sensor to detect an ultrasonic signal representative of a velocity of a fluid flowing through a lumen and to provide a measurement signal representative of the velocity;
(ii) a memory to store a template associated with a possible velocity of the fluid;
(iii) a processor, communicatively coupled to the sensor and to the memory, to perform a comparison of the measurement signal to the template and to determine an estimated velocity of the fluid based on the comparison; and
(iv) a communications interface, communicatively coupled to the processor, to transmit a representation of at least one of the estimated velocity and the measurement signal; and
(b) a server to receive the representation of the at least one of the estimated velocity and the measurement signal, the server comprising:
(i) an analytics engine to determine fluid usage information based on the at least one of the estimated velocity and the measurement signal; and
(ii) a billing engine to determine billing information based on the fluid usage information.
16. The system of claim 15 wherein at least one of the fluid flow meter and the analytics engine is configured to detect at least one of a change in the diameter of the lumen, a no-flow condition, a fluid leak, a freeze, and a malfunction based on the measurement signal, and
wherein the server is configured to alert the user via a wireless device of the at least one of the change in the diameter of the lumen, the no-flow condition, the fluid leak, the freeze, and the malfunction.
17. The system of claim 15 wherein the fluid usage information includes at least one of estimated fluid flow velocities, estimated fluid flow rates, number of fluid flow events, and durations of flow fluid events.
18. The system of claim 15 wherein the server is further configured to provide a dashboard displaying at least one of the fluid usage information and the billing information via a wireless device.
19. The system of claim 18 wherein the dashboard enables a fluid user and a fluid provider to access real-time data, historic data, and analysis of fluid usage.
20. The system of claim 18 wherein the dashboard enables a fluid user and a fluid provider to access comparisons of fluid usage with fluid usage by other fluid users.