Systems and methods for fluid leak detection

1 . A leak detection system comprising:

a pressure sensor measuring pressure of fluid within a hollow structure;

a fluid flow sensor measuring at least one of a fluid flow rate, a fluid flow velocity, or a fluid flow event duration;

a shut-off valve having an open state allowing fluid to enter the hollow structure and a closed state blocking fluid from entering the hollow structure; and

electric circuitry in communication with the pressure sensor and the shut-off valve and comprising one or more processors and one or more storage devices on which are stored instructions that are operable, when executed by the electric circuitry, to cause the electric circuitry to perform operations comprising:

obtaining, from the fluid flow sensor, a plurality of fluid flow measurements of the fluid in the hollow structure measured while the shut-off valve is in the open state;

determining whether the plurality of fluid flow measurements measured while the shut-off valve is in the open state do not satisfy at least one fluid flow signature and pressure measurements should be obtained, wherein the pressure measurements would not be obtained if the plurality of fluid flow measurements satisfy the at least one fluid flow signature;

detecting, using a result of the determination whether the plurality of fluid flow measurements measured while the shut-off valve is in the open state do not satisfy the at least one fluid flow signature, an abnormal fluid flow and that pressure measurements should be obtained,

in response to detecting the abnormal fluid flow and that pressure measurements should be obtained, obtaining, from the pressure sensor, a plurality of pressure measurements of the fluid in the hollow structure measured while the shut-off valve is in the closed state;

obtaining, from the pressure sensor, a different plurality of pressure measurements of the fluid in the hollow structure measured while the shut-off valve is in the open state;

determining that the plurality of pressure measurements measured while the shut-off valve is in the closed state change in a uniform direction indicating a pressure decrease over time, wherein determining that the plurality of pressure measurements measured while the shut-off valve is in the closed state change in the uniform direction indicating the pressure decrease over time uses one or more line fitting methods;

determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in another uniform direction indicating a pressure increase over time, wherein determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in the other uniform direction indicating the pressure increase over time uses one or more line fitting methods; and

identifying a fluid leak event in response to i) determining the pressure decrease over time of the plurality of pressure measurements while the shut-off valve is in the closed state, and ii) determining the pressure increase over time of the different plurality of pressure measurements while the shut-off valve is in the open state.

2 . The leak detection system of claim 1 , wherein identifying the fluid leak event comprises:

comparing the plurality of pressure measurements to the different plurality of pressure measurements; and

identifying the fluid leak event upon determining that the plurality of pressure measurements are less than the different plurality of pressure measurements by a difference greater than a predefined threshold value.

3 . The leak detection system of claim 1 , wherein the operations comprise:

actuating the shut-off valve to switch to the open state after obtaining the plurality of pressure measurements; and

obtaining the different plurality of pressure measurements of the fluid after actuating the shut-off valve.

4 . The leak detection system of claim 3 , wherein identifying the fluid leak event comprises:

identifying the fluid leak event based on a negative slope or a degree of decrease of the plurality of pressure measurements over time, or based on characteristics of a function associated with the plurality of pressure measurements over time.

5 . The leak detection system of claim 3 , wherein identifying the fluid leak event comprises:

maintaining the shut-off valve in the open state prior to obtaining the plurality of pressure measurements;

obtaining, prior to obtaining the plurality of pressure measurements, an initial plurality of pressure measurements of the fluid after causing the shut-off valve to switch to the open state;

actuating the shut-off valve to switch to the closed state after obtaining the initial plurality of pressure measurements; and

identifying the fluid leak event based on the initial plurality of pressure measurements, the plurality of pressure measurements, and the different plurality of pressure measurements.

6 . The leak detection system of claim 5 , wherein identifying the fluid leak event comprises:

comparing the plurality of pressure measurements to the different plurality of pressure measurements;

comparing the plurality of pressure measurements to the initial plurality of pressure measurements; and

identifying the fluid leak event upon determining that (i) the plurality of pressure measurements are less than the different plurality of pressure measurements by a first difference greater than a first predefined threshold value and (ii) the plurality of pressure measurements are less than the initial plurality of pressure measurements by a second difference greater than a second predefined threshold value.

7 . The leak detection system of claim 5 , wherein identifying the fluid leak event is (i) based on a positive slope or a first degree of increase of the plurality of pressure measurements over time and a negative slope or a second degree of decrease of the different plurality of pressure measurements over time, or (ii) based on characteristics of a function associated with the plurality of pressure measurements and the different plurality of pressure measurements over time.

8 . The leak detection system of claim 1 , wherein identifying the fluid leak event comprises:

identifying the fluid leak event based on characteristics of a function associated with the plurality of pressure measurements over time.

9 . The leak detection system of claim 1 , wherein identifying the fluid leak event comprises:

actuating the shut-off valve to switch to a second open state to allow the fluid to flow through the hollow structure after obtaining the plurality of pressure measurements;

obtaining a plurality of fluid flow rate measurements after actuating the shut-off valve to switch to the second open state;

estimating, using the plurality of fluid flow rate measurements, a fluid volume indicative of an amount of fluid flowing through the hollow structure after causing the shut-off valve to switch to the second open state;

comparing the fluid volume to a predefined fluid volume value; and

identifying the fluid leak event further based on the comparison of the fluid volume to the predefined fluid volume value.

10 . The leak detection system of claim 1 , wherein:

determining that the plurality of pressure measurements indicate a pressure decrease over time comprises determining, using the one or more line fitting methods, that a line for the plurality of pressure measurements measured while the shut-off valve is in the closed state has a negative slope indicating the pressure decrease over time; and

determining that the different plurality of pressure measurements indicate a pressure increase over time comprises determining, using the one or more line fitting methods, that the different plurality of pressure measurements measured while the shut-off valve is in the open state has a positive slope indicating the pressure increase over time.

11 . The leak detection system of claim 1 , wherein identifying the fluid leak event is responsive to i) determining that the plurality of pressure measurements measured while the shut-off valve is in the closed state change in the uniform direction indicating a pressure decrease over time and ii) determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in the other uniform direction indicating a pressure increase over time.

12 . A method of leak detection comprising:

obtaining, from a fluid flow sensor measuring at least one of a fluid flow rate, a fluid flow velocity, or a fluid flow event duration, a plurality of fluid flow measurements of the fluid in a hollow structure measured while a shut-off valve is in an open state;

determining whether the plurality of fluid flow measurements measured while the shut-off valve is in the open state do not satisfy at least one fluid flow signature and pressure measurements should be obtained, wherein the pressure measurements would not be obtained if the plurality of fluid flow measurements satisfy the at least one fluid flow signature;

detecting, using a result of the determination whether the plurality of fluid flow measurements measured while the shut-off valve is in the open state do not satisfy the at least one fluid flow signature, an abnormal fluid flow and that pressure measurements should be obtained,

in response to detecting the abnormal fluid flow and that pressure measurements should be obtained, obtaining, by a pressure sensor, a plurality of pressure measurements of a fluid in a hollow structure measured while a shut-off valve is in a closed state;

obtaining, by the pressure sensor, a different plurality of pressure measurements of the fluid measured while the shut-off valve is in the open state;

determining that the plurality of pressure measurements measured while the shut-off valve is in the closed state change in a uniform direction indicating a pressure decrease over time, wherein determining that the plurality of pressure measurements measured while the shut-off valve is in the closed state change in the uniform direction indicating the pressure decrease over time uses one or more line fitting methods;

determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in another uniform direction indicating a pressure increase over time, wherein determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in the other uniform direction indicating the pressure increase over time uses one or more line fitting methods; and

identifying a fluid leak event in response to i) determining the pressure decrease over time of the plurality of pressure measurements while the shut-off valve is in the closed state, and ii) determining the pressure increase over time of the different plurality of pressure measurements while the shut-off valve is in the open state.

13 . The method of claim 12 , wherein identifying the fluid leak event comprises:

comparing the plurality of pressure measurements to the different plurality of pressure measurements; and

identifying the fluid leak event upon determining that the plurality of pressure measurements are less than the different plurality of pressure measurements by a difference greater than a predefined threshold value.

14 . The method of claim 12 , wherein obtaining the different plurality of pressure measurements comprises:

actuating the shut-off valve to switch to the open state after obtaining the plurality of pressure measurements; and

obtaining, by the pressure sensor, the different plurality of pressure measurements of the fluid after actuating the shut-off valve.

15 . The method of claim 14 , wherein identifying the fluid leak event comprises:

identifying the fluid leak event based on (i) a negative slope or a degree of decrease of the plurality of pressure measurements over time, or (ii) characteristics of a function associated with the plurality of pressure measurements over time.

16 . The method of claim 14 , wherein identifying the fluid leak event comprises:

maintaining the shut-off valve in the open state prior to obtaining the plurality of pressure measurements;

obtaining, by the pressure sensor, an initial plurality of pressure measurements of the fluid after causing the shut-off valve to switch to the open state;

actuating the shut-off valve to switch to the closed state after obtaining the initial plurality of pressure measurements; and

identifying the fluid leak event based on the initial plurality of pressure measurements, the plurality of pressure measurements, and the different plurality of pressure measurements.

17 . The method of claim 16 , wherein identifying the fluid leak event comprises:

comparing the initial plurality of pressure measurements to the plurality of pressure measurements;

comparing the plurality of pressure measurements to the different plurality of pressure measurements; and

identifying the fluid leak event upon determining that (i) the plurality of pressure measurements are less than the initial plurality of pressure measurements by a first difference greater than a first predefined threshold value, and (ii) the plurality of pressure measurements are less than the different plurality of pressure measurements by a second difference greater than a second predefined threshold value.

18 . The method of claim 16 , wherein identifying the fluid leak event comprises:

identifying the fluid leak event (i) based on a positive slope or a first degree of increase of the different plurality of pressure measurements over time and a negative slope or a second degree of decrease of the plurality of pressure measurements over time, or (ii) based on characteristics of a function associated with the plurality of pressure measurements and the different plurality of pressure measurements over time.

19 . The method of claim 12 , wherein identifying the fluid leak event comprises:

Identifying the fluid leak event based on characteristics of a function associated with the plurality of pressure measurements over time.

20 . The method of claim 12 , wherein identifying the fluid leak event comprises:

actuating the shut-off valve to switch to a second open state to allow the fluid to flow through the hollow structure after obtaining the plurality of pressure measurements;

generating, by the pressure sensor, a plurality of fluid flow rate measurements after actuating the shut-off valve to switch to the second open state;

estimating and using the plurality of fluid flow rate measurements, a fluid volume indicative of an amount of fluid flowing through the hollow structure after causing the shut-off valve to switch to the second open state;

comparing the fluid volume to a predefined fluid volume value; and

identifying the fluid leak event further based on the comparison of the fluid volume to the predefined fluid volume value.

21 . A non-transitory computer storage medium encoded with instructions that, when executed by one or more computers, cause the one or more computers to perform operations comprising:

obtaining, from a fluid flow sensor measuring at least one of a fluid flow rate, a fluid flow velocity, or a fluid flow event duration, a plurality of fluid flow measurements of a fluid in a hollow structure measured while a shut-off valve is in an open state;

determining whether the plurality of fluid flow measurements measured while the shut-off valve is in the open state do not satisfy at least one fluid flow signature and pressure measurements should be obtained, wherein the pressure measurements would not be obtained if the plurality of fluid flow measurements satisfy the at least one fluid flow signature;

detecting, using a result of the determination whether the plurality of fluid flow measurements measured while the shut-off valve is in the open state do not satisfy the at least one fluid flow signature, an abnormal fluid flow and that pressure measurements should be obtained,

in response to detecting the abnormal fluid flow and that pressure measurements should be obtained, obtaining, from a pressure sensor, a plurality of pressure measurements of a fluid in a hollow structure measured while a shut-off valve is in a closed state;

obtaining, from the pressure sensor, a different plurality of pressure measurements of the fluid in the hollow structure measured while the shut-off valve is in the open state;

determining that the plurality of pressure measurements measured while the shut-off valve is in the closed state change in a uniform direction indicating a pressure decrease over time, wherein determining that the plurality of pressure measurements indicate a pressure decrease over time comprises determining, using one or more line fitting methods, that a line for the plurality of pressure measurements measured while the shut-off valve is in the closed state has a negative slope indicating the pressure decrease over time;

determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in another uniform direction indicating a pressure increase over time, wherein determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in the other uniform direction indicating the pressure increase over time uses the one or more line fitting methods; and

identifying a fluid leak event in response to i) determining that the plurality of pressure measurements measured while the shut-off valve is in the closed state change in the uniform direction indicating a pressure decrease over time using the one or more line fitting methods, and ii) determining that the different plurality of pressure measurements measured while the shut-off valve is in the open state change in the other uniform direction indicating a pressure increase over time using the one or more line fitting methods.