System and method of monitoring a diagnostic system of a process control system

Monitoring systems and methods for a relief valve system. In one example, a monitoring system for a relief valve includes at least one tilt sensor coupled to one or more of a cover or a latch of the relief valve. The at least one tilt sensor is associated with an interface. Upon detection by the at least one tilt sensor that one of the cover is open or the latch is unlocked, a signal is transmitted by the interface indicating one or more of the cover is open or the latch is unlocked.

FIELD OF THE DISCLOSURE

The disclosure generally relates to process control systems and, more specifically, to a system and method of monitoring a diagnostic system of the process control system.

BACKGROUND OF THE DISCLOSURE

Process control systems often employ control valves to control the flow of process fluids. Relief systems, such as relief valves, are typically used for various control valves and include emergency pressure relief vents and pressure vacuum relief valves. In some examples, the conventional relief systems are coupled to a tank and monitored by observing an overall pressure of the tank. In other examples, physical, visual indicators are attached to one or more parts of the valve and require physical inspection to determine a state of the relief system, for example.

An increasing number of laws have been enacted on limiting an amount of volatile organic compounds (VOCs) being emitted from process control systems. The VOCs include organic compounds that easily become vapors or gases and contain elements that may cause various health effects including eye, nose and throat irritation, headaches, nausea, and links to cancer. As a result, for at least this reason, it is imperative for companies to constantly monitor relief valve systems to avoid or minimize fines and an excess amount of harmful VOCs being emitted into the environment.

SUMMARY OF THE DISCLOSURE

In accordance with a first exemplary aspect of the present disclosure, a monitoring system for a relief valve, the relief valve having a body and a cover coupled to the body by a latch, comprises at least one tilt sensor adapted to be coupled to one or more of the cover or the latch of the relief valve. The monitoring system further includes an interface associated with the at least one tilt sensor. Upon detection by the at least one tilt sensor that an angle of one or more of the cover or the latch is greater than zero, the interface transmits a signal indicating one or more of the cover is open or the latch is unlocked.

In accordance with a second exemplary aspect of the present disclosure, a monitoring system for a relief valve comprises a first wireless accelerometer adapted to be coupled to a first portion of a control assembly near a first relief opening and is for detecting a valve disk is in the open position. The relief valve includes a body having the first relief opening and a second relief opening, a cover coupled to the body, a control assembly disposed within the body and having a valve disk moveable between an open position and a closed position. The monitoring system further comprises a second wireless accelerometer adapted to be coupled to a second portion of the control assembly near the second relief opening and is for detecting the valve disk is in the open position. A first interface is associated with the first wireless accelerometer, and a second interface is associated with the second wireless accelerometer. Upon detection by the first wireless accelerometer of acceleration of the first portion of the control assembly in a direction toward an open position, the first interface transmits a signal indicating the valve disk is in the open position. In addition, upon detection by the second wireless accelerometer of acceleration of the second portion of the control assembly in a direction toward the open position, the second interface transmits a signal indicating the valve disk is in the open position.

According to a further exemplary aspect of the present disclosure, a monitoring system for a relief vent, the relief vent comprising a base adapted to be coupled to a tank and a cover rotatably coupled to the base by a hinge mechanism, comprises one of a tilt sensor coupled to the cover or a rotary motion sensor coupled to the hinge mechanism. One of the tilt sensor or the rotary motion sensor is for detecting an angle of the cover relative to an axis. An interface is associated with the tilt sensor or the rotary motion sensor. Upon detection by one of the tilt sensor or the rotary motion sensor the angle of the cover is greater than zero, the interface transmits an alarm signal indicating the cover is open.

According to another exemplary aspect of the present disclosure, a monitoring system for a pressure vacuum relief valve comprises one of a first travel sensor or a first wireless accelerometer adapted to be coupled to a pressure pallet and is for measuring a distance traveled by the pressure pallet. The pressure vacuum relief valve includes a body defining a pressure chamber and a vacuum chamber, the pressure chamber having a valve seat and a pressure pallet adapted to sealingly engage the valve seat, and the vacuum chamber having a valve seat and a vacuum pallet adapted to sealingly engage the valve seat of the vacuum chamber. The monitoring system for the pressure vacuum relief valve further comprises one of a second travel sensor or a second wireless accelerometer adapted to be coupled to the vacuum pallet and for measuring a distance traveled by the vacuum pallet. A first interface is associated with one of the first travel sensor or the first wireless accelerometer. In addition, a second interface is associated with one of the first travel sensor or the second wireless accelerometer. Upon detection by one of the first and second the travel sensors or the first and second wireless accelerometers that the distance traveled by the pressure pallet or the vacuum pallet remains constant in a direction associated with an open position of one or more of the pressure pallet or the vacuum pallet, one or more of the first interface or the second interface transmits a signal indicating one or more of the pressure pallet or the vacuum pallet is failing to close. In addition, upon detection by one of the first travel sensor or the first wireless accelerometer that the distance traveled by the pressure pallet is zero and a pressure in a tank of the body of the valve is greater than a setpoint pressure, the first interface transmits a signal indicating the pressure pallet is failing to open. Also, upon detection by one of the second travel sensor or the second wireless accelerometer, that the distance traveled by the pressure pallet is zero and the pressure in the tank is less than a setpoint pressure, the second interface transmits a signal indicating the vacuum pallet is failing to open.

In accordance with yet another aspect, a method of monitoring a diagnostic system of a process control system comprises coupling a tilt sensor to one or more of a latch, an arm, or a cover of a diagnostic system, and monitoring a position of one or more of the latch, the arm or the cover relative to an axis via the tilt sensor. The method further comprises detecting, via the tilt sensor, one or more of the latch, the cover, or the arm is disposed at an angle from an axis that is greater than zero, and transmitting, via an interface, a signal indicating the cover is open.

In accordance with yet another aspect, a method of monitoring a relief valve of a process control system comprises coupling a first wireless accelerometer to a first portion of a control assembly near a first relief opening of the relief valve and a second wireless accelerometer to a second portion of the control assembly near to a second relief opening of the relief valve. The method further comprises detecting, via the first wireless accelerometer, acceleration of a first portion of the control assembly, and detecting, via the second wireless accelerometer, acceleration of the second portion of the control assembly. Upon detecting acceleration of the first portion of the control assembly in a direction toward an open position, the method comprises transmitting, via an interface associated with the first wireless accelerometer, a signal indicating a valve disk of the control assembly is in an open position. In addition, upon detecting acceleration of the second portion of the control assembly in a direction toward the open position, the method also comprises transmitting, via an interface associated with the second wireless accelerometer, a signal indicating the valve disk of the control assembly is in the open position.

In accordance with yet another aspect, a method of monitoring a relief vent of a process control system comprises coupling one of a tilt sensor to a cover of a relief vent or a rotary motion sensor to a hinge mechanism of the relief vent, the hinge mechanism coupling the cover to a base of the relief vent, and the base having an axis. The method further comprises measuring a position of the cover via one of the tilt sensor or the rotary motion sensor, and detecting, via one of the tilt sensor or the rotary motion sensor, when the cover is disposed at an angle from the axis of the base that is greater than zero. The method also comprises transmitting, via an interface, a signal indicating the cover is open upon detecting the cover is disposed at an angle from the axis of the base that is greater than zero.

In accordance with still yet another aspect, a method of monitoring a relief valve comprises coupling one of a travel sensor or a wireless accelerometer to a pressure pallet and a vacuum pallet of the relief valve and measuring a distance traveled by one or more of a pressure pallet or a vacuum pallet via one of the travel sensor or the wireless accelerometer disposed on the pressure pallet or the vacuum pallet. The method further comprises detecting, via one or more of the travel sensor or the wireless accelerometer, one or more of the pressure pallet or the vacuum pallet is failing to close when the distance traveled by the pressure pallet or the vacuum pallet remains constant in a direction associated with an open position of the relief valve. The method further comprises detecting, via one or more of the travel sensor or the wireless accelerometer, the pressure pallet is failing to open when the distance traveled by the pressure pallet is zero and a pressure of a tank of the relief valve is greater than a setpoint pressure. The method still further comprises detecting, via one or more of the travel sensor or the wireless accelerometer, the vacuum pallet is failing to open when the distance traveled by the vacuum pallet is zero and the pressure of the tank is less than the setpoint pressure. The method also comprises transmitting a signal, via one or more interfaces associated with one of the travel sensor or the wireless accelerometer, when detecting one or more of the vacuum pallet or the pressure pallet is one or more of open or failing to open.

In further accordance with any one or more of the foregoing exemplary aspects, the monitoring system may comprise a base station including a base processor and a base memory, and the base station may be communicatively coupled to one of the tilt sensor or the wireless accelerometer via a wireless network and adapted to receive the signal transmitted by the interface.

In some preferred forms, the monitoring system may further comprise a temperature sensor for measuring the temperature of the tank and a pressure sensor coupled for measuring the pressure of the tank, each of the temperature sensor and the pressure sensor having an interface for transmitting a signal indicating one of the measured temperature or the measured pressure. Further, each of the measured temperature, the measured pressure, and the detected distance traveled by one or more of the pressure pallet and the vacuum pallet, or the angle of the cover of the relief valve may be used to estimate an instantaneous fluid flow value F out of the pressure vacuum relief valve during an overpressure event.

In some other preferred forms, the method may include detecting, via one or more of the first and second wireless accelerometers, one or more of an opening speed or a closing speed of the valve disk of the control assembly. In addition, the method may further include detecting, via one or more of the first and second wireless accelerometers, oscillatory movement of one or more of the first portion of the control assembly or the second portion of the control assembly, the oscillatory movement indicating the valve disk is in the open position.

Additional optional aspects and features are disclosed, which may be arranged in any functionally appropriate manner, either alone or in any functionally viable combination, consistent with the teachings of the disclosure. Other aspects and advantages will become apparent upon consideration of the following detailed description.

DETAILED DESCRIPTION

Generally, the present disclosure is directed to methods and systems of monitoring relief valves by sensing movement, orientation and/or acceleration (instead of pressure or flow) of one or more parts of the relief valve. In particular, the monitoring systems use one or more of a rotary motion sensor, a tilt sensor, a travel sensor, a wireless accelerometer, and/or a gyroscope to determine a state of the relief valve. In this manner, the state of the relief valve, including whether it is operating correctly, in an open or a closed position, or experiencing different behaviors, such as oscillation, can be determined. As a result, the detection of pressure and flow of fluid of a tank associated with the relief valve in conventional relief valve monitoring systems and methods is not required.

In one example, the various motion sensors are communicatively coupled to a remote base station, which receives signals from one or more of the sensors indicating a current state or condition of the relief valve. So configured, diagnostic information about the relief valve is transmitted through a wireless network and to the base station, allowing the relief valve and/or process control system to be remotely monitored without having to physically examine fluid leaving a tank associated with the relief valve, for example. Various configurations and examples of this present disclosure are described more below.

Referring now toFIG. 1, a monitoring system10for a diagnostic system12of a process control system14according to aspects of the present disclosure is depicted. The process control system14includes at least one tank16and the diagnostic system12may be coupled to the tank16. The diagnostic system12may include one of an emergency pressure relief vent, a pressure vacuum relief valve, and/or a lockdown hatch, as explained more below. The monitoring system10includes at least one motion detector17coupled to the diagnostic system12. As explained more below, the motion detectors17may include one or more of a rotary motion sensor, a tilt sensor, an wireless accelerometer, a travel sensor, or a gyroscope, each of which may include a memory18, a processor19coupled to the memory18, a transmitter19and an interface20.

In another example, the monitoring system10includes a base station22located remotely from the process control system14and monitoring system10. The base station22is communicatively coupled to the monitoring system10via a wireless network24, as depicted inFIG. 1. The base station22includes a base memory26, a base processor28, a base transmitter30, and a base interface32, all of which interact with the motion detectors17and associated interface21, as explained more below. So configured, at least one or more motion detectors17detect movement of one or more parts of the diagnostic system12and the signal is transmitted, such as by the interface21associated with the motion detector18to the base station22, indicating a state of the relief system. In some examples, the signal transmitted is an alarm signal indicating the diagnostic system includes a relief valve which is one of failing to open or failing to close, for example, allowing a remote operator to understand the state of the diagnostic system12without having to physically evaluate the diagnostic system12.

In one example, and referring now toFIGS. 2 and 3, an exemplary monitoring system100for a diagnostic system12of the present disclosure is depicted. In this example, the exemplary diagnostic system12is a relief valve120, such as Enardo Models ES-660 and ES-660-L Thief Hatches. The relief valve120is adapted to be coupled to a tank, such as the tank16(FIG. 1) of the process control system14, and includes a body122with a flow passageway123and a cover124rotatably attached to the body122by a latch126. As depicted inFIG. 2, the body122includes an axis A, the cover124includes an axis C, and the latch126includes an axis L. In one example, when each of the cover124and the latch126are in an initial position, such as a closed position (FIG. 2), the axis C of the cover is parallel to the axis A of the body, such that the cover is not disposed from an angle of the axis A of the body122. Likewise, the axis L of the latch126is also not disposed from an angle of the axis A of the body122in this initial position.

Further, a control assembly128is disposed in the body122and enclosed by the cover124. The control assembly128includes a valve disk130adapted to move between an open position in which fluid flows through the flow passageway123and a closed position in which fluid is prevented from flowing through the flow passageway123. The relief valve120also includes a first relief opening132disposed adjacent to the valve disk130and a second relief opening134.

As depicted inFIG. 2, at least one tilt sensor136is disposed on a portion of the latch126and another tilt sensor136is disposed on the cover126. Each tilt sensor136is associated with an interface21(FIG. 1), such as the interface121depicted. So configured, upon detection by the at least one tilt sensor136that one or more of the latch126or the cover124is disposed at an angle from the axis A of the body122that is greater than zero, an alarm signal is transmitted indicating the cover124of the relief valve120is one of open or not securely closed. In one example, the interface121of the tilt sensor136transmits the alarm signal to the base station22(FIG. 1), informing the operator of the state of the relief valve120.

In one example, the at least one tilt sensor136includes a first tilt sensor136aadapted to be coupled to the latch126and a second tilt sensor136badapted to be coupled to the cover124. In this example, the first tilt sensor136adetects when an angle of the latch126is greater than zero relative to an axis, such as the axis A of the body122, and, therefore, that the latch126is unlocked. In addition, the second tilt sensor136bdetects when an angle of the cover124is greater than zero relative to an axis, such as the axis A of the body122, and, therefore, that the cover124is open.

In another example, the at least one tilt sensor136includes the first tilt sensor136aadapted to be coupled to an arm, such as the arm226inFIG. 4, as explained more below, and the second tilt sensor136bcoupled to a cover, such as the cover224, also ofFIG. 4, as explained more below. In this example, the first tilt sensor136adetects when an angle of the arm226is greater than zero relative to an axis, and, therefore, that the cover224is open. In a similar manner, the second tilt sensor136bdetects when an angle of the cover224is greater than zero relative to an axis, and, therefore, that the cover224is open.

Alternatively, and as depicted inFIG. 3, instead of or in addition to using the tilt sensors136on the latch126and cover124of the relief valve120, as inFIG. 2, a pair of wireless accelerometers138may be coupled to other portions of the relief valve120. Specifically, and in this example, a first wireless accelerometer140of the pair of wireless accelerometers138is coupled to a first portion137of the control assembly128immediately adjacent to the first relief opening132. In addition, a second wireless accelerometer142of the pair of wireless accelerometers138is coupled to a second portion139of the relief valve120immediately adjacent to the second relief opening134, as depicted inFIG. 3. The first wireless accelerometer140detects motion, such as acceleration, of the first portion137of the control assembly124in a first direction, such as a direction associated with an open position, e.g., a direction away from the base122. An interface141associated with the first wireless accelerometer140then transmits a signal indicating the valve disk130is in the open position. In a similar manner, the second wireless accelerometer142detects motion, such as acceleration, of the second portion139of the control assembly128in the first direction, such as the direction associated with the open position. An interface143associated with the second wireless accelerometer142transmits a signal indicating the valve disk130is in the open position. More generally, the operation of the pressure relief and/or the vacuum relief functions are sensed, as further explained below.

The first interface141associated with the first wireless accelerometer140may transmit a signal, such as an alarm signal to the base station22(FIG. 1), upon detection that the valve disk130is in the open position. Likewise, the second interface142associated with the second wireless accelerometer142may transmit a signal, such as an alarm signal to the base station22, upon detection that the valve disk130is in an open position. In addition, each of the first and second wireless accelerometers140,142also may detect oscillatory motion of one or both of the first portion137and the second portion139of the control assembly128. The detection of oscillatory motion further indicates the valve disk130is in the open position. Moreover, the first wireless accelerometer140may detect upward movement of the first portion137of the control assembly128without downward movement, indicating the valve disk130is in the open position. Likewise, the second wireless accelerometer142may detect upward movement of the second portion139of the control assembly128without downward movement, indicating the valve disk130is in the open position.

Referring now toFIGS. 4 and 5, another exemplary monitoring system200for a diagnostic system12of the present disclosure is depicted. In this example, the exemplary diagnostic system12is a lockdown hatch220, such as Enardo Model1000. Lock Down Hatch. The lockdown hatch220is adapted to be coupled to a tank, such as the tank16(FIG. 1) of the process control system14, and includes a body221with a flow passageway223(FIG. 5) and a cover224attached to an arm226having a handle228. Upon movement of the arm226and the handle228in a direction away from the cover224, for example, the cover224is lifted upward with the arm226and the flow passageway223is open, providing relief. Like the relief valve120ofFIG. 2, at least one tilt sensor136is coupled to the arm226or the cover222, and the interface121is associated with each tilt sensor136.

So configured, upon detection by the at least one tilt sensor136that one or more of the arm226or the cover222is disposed at an angle from an axis B of the body221(FIG. 5) that is greater than zero, an alarm signal is transmitted indicating one or more of the arm226or the cover222of the lockdown hatch220is one of open or not securely closed. In one example, the interface20of the tilt sensor136transmits the alarm signal to the base station22(FIG. 1), informing the operator of the state of the lockdown hatch220.

Referring now toFIGS. 6 and 7, another exemplary monitoring system300of the diagnostic system12of the present disclosure is depicted. In this example, the exemplary diagnostic system12is a relief vent320, such as an Enardo Pressure Relief Vent, model2000. The relief vent320may also be adapted to be coupled to the tank16(FIG. 1) of the process control system14and includes a base322and a cover324rotatably mounted to the base322by a hinge mechanism326. In this example, one of a tilt sensor136is coupled to the cover324or a rotary motion sensor340is coupled to the hinge mechanism326. Each of the tilt sensor136and the rotary motion sensor340detects a change in an angle of the cover324relative to an axis, such as an axis D of the base322. Each of the tilt sensor136and the rotary motion sensor340is associated with the interface121.

So configured, upon detection the cover324is disposed at an angle from the axis D of the base322of the relief vent320that is greater than zero, the interface121transmits a signal indicating the cover324is open, as depicted inFIGS. 6 and 7. In addition, upon detection that the cover324is not disposed at an angle from the axis D of the base322that is greater than zero, the interface121transmits a signal indicating the cover324is closed. In one example, the signal transmitted by the interface20is an alarm signal, and the interface121transmits the alarm signal to the remotely located base station22(FIG. 1) coupled to the process control system14via the network24, for example, informing the operator of the state of the relief vent320.

In another example, and as depicted inFIG. 7, a tank temperature sensor342may be coupled to a portion of the tank16(FIG. 1), such as a body of the tank16, to which the relief vent320is adapted to be attached. In addition, a pressure sensor344may be coupled to another portion of the tank16, again such as the body of the tank16, to which the relief vent320is adapted to be attached. The temperature sensor342may continuously measure the temperature of the tank16, and the pressure sensor344may continuously measure the pressure of the tank16. So configured, each of the measured temperature of the tank, the measured pressure of the tank16, and the cover angle data measured by one of the tilt sensor136or the rotary motion sensor340may be used to estimate a fluid flow total during an overpressure event, for example and as explained more below.

More specifically, the fluid flow value F is calculated, by one or more processors, in accordance with the following formula:

PT=Absolute pressure of gas in tank

TT=Absolute temperature of gas in tank

G=specific gravity of gas in tank

Θ=cover angle or cover position

K1=Absolute temperature constant

K2=cover angle constant

K3=Trim shape constant

In addition, and in one example, the monitoring system300may further include one or more of a wireless accelerometer or a gyroscope coupled to a portion of the cover324and for sensing one or more of the motion and position of the cover324.

Referring now toFIGS. 8 and 9, another exemplary monitoring system400for the diagnostic system12of the present disclosure is depicted. In this example, the exemplary diagnostic system12is a pressure vacuum relief valve (PVRV), such as an Enardo Pressure Vacuum Relief Valve, Model850. The pressure vacuum relief valve420includes a body422defining an inlet424, an outlet426, a pressure chamber428, and a vacuum chamber430. The pressure chamber428is enclosed by a lid432and includes a valve seat434and a pressure pallet436, which together form a seal and prevent any vapors to pass through the outlet426during normal operation. Likewise, the vacuum chamber430is enclosed by a lid438and includes a valve seat440and a vacuum pallet442, which together form a seal, preventing vapors from passing through the outlet426, for example. So configured, the pressure vacuum relief valve420maintains a tight seal until system pressure or vacuum exceed the set pressure of the pressure vacuum relief valve420, for example. When overpressure occurs, the pressure pallet436lifts, breaking the seal between one or more of the valve seat434and corresponding pallet436. When underpressure occurs, i.e., increased vacuum, the vacuum pallet442lifts. Upon relief, the pressure vacuum relief valve420reseals and remains sealed.

The monitoring system400of the pressure vacuum relief valve420and includes a first travel sensor450attached to the pressure pallet436and a second travel sensor452attached to the vacuum pallet442. Alternatively, and as depicted inFIG. 9, a first wireless accelerometer454may be attached to the pressure pallet436and a second wireless accelerometer456may be attached to the vacuum pallet442(instead of using the first and second travel sensors450,452ofFIG. 8). In either example, both the first travel sensor450and the first wireless accelerometer454measure a distance traveled by the pressure pallet436relative to a period of time, for example. Both the first travel sensor450and the first wireless accelerometer454also detect movement of the pressure pallet436in a direction associated with an open position of the relief valve420, such as a direction away from the valve seat434when a distance traveled by the pressure pallet436is greater than zero, for example. In addition, both the first travel sensor450and the first wireless accelerometer454detect the pressure pallet436is failing to open, e.g., stuck in a closed position, when the distance traveled of the pressure pallet436remains at zero during an overpressure event, as described more below.

In a similar manner, both the second travel sensor452and the second wireless accelerometer456measure a distance traveled by the vacuum pallet442relative to a period of time, for example, and detect movement of the vacuum pallet442in a direction associated with an open position of the relief valve, e.g., moved away from the valve seat440when a distance traveled by the vacuum pallet442is greater than zero. In addition, both the second travel sensor452and the second wireless accelerometer456detect the vacuum pallet442is failing to open, e.g., stuck in a closed position, when the distance traveled by the vacuum pallet442remains at zero during a vacuum event.

Further, each of the first and second travel sensors450,452and the first and second wireless accelerometers454,456is associated with an interface458that implements a signal, such as an alarm signal, when it is detected one or more of the pressure pallet436or the valve pallet442is open, failing to open, or failing to close, as explained more below.

In another example, and as depicted inFIG. 8, a pressure sensor460is attached to a tank portion459of the body422of the pressure vacuum relief valve420. In addition, a temperature sensor462is also attached to the tank portion459of the body422of the pressure vacuum relief valve420. The pressure sensor460measures pressure in the tank portion458and the temperature sensor462measures pressure in the tank portion458relative to a period of time, for example. Each of the pressure sensor460and the temperature sensor462is associated with an interface that transmits a signal indicating one of the measured temperature or the measured pressure to the base station22, for example. So configured, a fluid flow value F out of the tank458may be estimated by one or more processors, such as the processor28of the base station22, for example, (FIG. 1) based on the measured temperature, the measured pressure of the tank, and the distance traveled by the pressure pallet436during an overpressure event, as also explained more below. More specifically, and in one example, the fluid flow value F is calculated in accordance with the following formula:

Where

PT=Absolute pressure of gas in tank

TT=Absolute temperature of gas in tank

G=specific gravity of gas in tank

Y=pressure pallet distance traveled

K1=Absolute temperature constant

K2=Pressure pallet travel constant

K3=Trim shape constant

Referring now toFIGS. 10A-10B, flow charts of example methods500and600of monitoring a diagnostic system of a process control system14are depicted. The methods500and600may be implemented, in whole or part, on one or more of the devices or systems such as those depicted in the monitoring system10ofFIG. 1, the monitoring system100ofFIGS. 2 and 3, the monitoring system200ofFIGS. 4 and 5, and the monitoring system300ofFIGS. 6 and 7, as explained more below. The methods500and600may be saved as a set of instructions, routines, programs, or modules on memory, such as a memory18of one of the previously defined motion detectors17or the base station memory26ofFIG. 1, and may be executed by a processor, such as the processor19of one of the motion detectors17or the base processor28ofFIG. 1.

The method500begins when a tilt sensor136is coupled to one or more of the cover124,224,324, latch126or arm226of one of the relief valves120,220or the relief vent320, as described above. After being coupled to the relevant portion of the relief valves120,220or the relief vent320, the tilt sensors136are zeroed (Block502) at installation. In the example ofFIGS. 6 and 7, as an alternative, the rotary motion sensor340may be coupled to the hinge mechanism326and zeroed after installation. After this step, the tilt sensors136monitor a position, such as an angle, of one or more of the latch126, arm226, or cover124,224,324relative to an axis, such as one of axis A, B, C and D, depending upon the diagnostic system12being monitored. More specifically, the tilt sensors136may monitor the angle of the latch126and the cover124of the relief valve120ofFIG. 2relative to axis A of the base122, axis L of the latch126or axis C of the cover124, for example. In addition, the tilt sensor136may monitor the angle of the arm226or the angle of the cover224relative to an axis B of the base221(FIG. 5) and may monitor the angle of the cover324relative to the axis D of the base322(FIGS. 6 and 7). In the example ofFIGS. 6 and 7, the alternative rotary motion sensor340may monitor the angle of the cover relative to the axis D, for example.

In block506, the tilt sensor136or the rotary motion sensor340(FIGS. 6-7) detects when the angle of one or more of the latch126, the arm226, or the cover124,224,324is greater than zero, such as greater than zero relative to a respective axis of orientation, including one of axis A, B, C or D, for example, explained above. If the angle is greater than zero, the interface121associated with the tilt sensor136or an interface associated with the rotary motion sensor340transmits a signal, such as an alarm signal, indicating one or more of the latch126, the arm226or the cover124,224,324is open in Block508. In one example, the signal is transmitted to the base station22(FIG. 1) via the wireless network24, allowing an operator to remotely understand the state of the relief valve system12without having to physically inspect/evaluate. If the angle is less than zero, the interface121associated with the tilt sensor136or the interface associated with the rotary motion sensor340transmits a signal indicating one or more of the latch126, the arm226or the cover124,224,324is closed (Block510), and the tilt sensors136and/or rotary motion sensor340continue to monitor one or more of the latch126, the arm226or the cover124,224,324(Block504). In one example, this signal may also be transmitted to the base station22via the wireless network24. In another example, transmitting the signal indicating the cover124,224,324is open may include transmitting an alarm signal one or more of only during a preset period of time or when one or more of the latch126, the cover124,224,324or the arm226is disposed at an angle from an axis greater than zero for a preset period of time.

Referring now toFIG. 10B, the monitoring system300ofFIG. 7may alternatively include the additional method600depicted inFIG. 10B. The method600begins with measuring tank pressure by the tank pressure sensor344and tank temperature by the tank temperature sensor342in addition to the angle of the cover324relative to the axis D of the base322, for example, of the relief vent320(Block602). In one example, the measured tank temperature and pressure and angle of the cover324data is transmitted by the interface121associated with the tilt sensor136(or the interface associated with the rotary motion sensor) to the base station22(FIG. 1).

In block604, a processor, such as the processor28of the base station22, calculates an instantaneous fluid flow rate value F out of the tank based on the measured pressure, measured temperature, and angle of the cover data. More specifically, the fluid flow value F is calculated in accordance with the following formula:

PT=Absolute pressure of gas in tank

TT=Absolute temperature of gas in tank

G=specific gravity of gas in tank

Θ=cover angle or cover position

K1=Absolute temperature constant

K2=cover angle constant

K3=Trim shape constant

In block606, the method600further includes estimating a total fluid flow value F out of the tank during a period of time of an overpressure event, for example. More specifically, the instantaneous fluid flow rate value F is calculated at a first period of time, such as when the recorded overpressure event began. A second instantaneous fluid flow rate value may then be calculated at a second period of time, such as when the recorded overpressure event ended. From this data, an estimated total fluid flow F value out of the tank from the first period of time until the second period of time may be calculated.

Referring now toFIGS. 11A-11B, flow charts of example methods700and800of monitoring a relief valve are depicted. The methods700and800may be implemented, in whole or part, on one or more of the devices or systems such as those depicted in the monitoring system10ofFIG. 1and the monitoring system400ofFIGS. 8 and 9, as explained more below. The method may be saved as a set of instructions, routines, programs, or modules on memory such as base station memory26ofFIG. 1, and may be executed by a processor, such as the base processor28ofFIG. 1.

Referring now toFIG. 11A, and in one example, the method700may begin with a user or an operator entering a pressure setpoint value for the pressure of the tank of the pressure vacuum relief valve420(FIGS. 8 and 9) in Block702. Next, the method700may include measuring the pressure of the tank459of the pressure vacuum relief valve420via the pressure sensor460(FIG. 8) in Block704. In another example, the method may further include measuring the temperature of the tank459via the temperature sensor458. In addition, the method700includes measuring via the travel sensor450disposed on the pressure pallet436a distance traveled by the pressure pallet436, also in Block704. In one example, the method700may further including transmitting via one or more interfaces associated with the travel sensor, a signal indicating the distance traveled by the pressure pallet436, for example, for a period of time, to the base station22or the remote computing device. The base station22or other remote device may save the distance traveled data to the memory26of the base station22or other computing device for use later in calculating an estimated fluid flow value F during an overpressure event, as described above.

In Block706, using this data, the method700further includes determining, via one or more processors, such as the processor28of the base station22, whether the measured tank pressure is greater than or less than and equal to the setpoint pressure. In either scenario, the method700then includes detecting whether the pressure pallet travel is greater than zero (Blocks708and710). When the measured tank pressure is greater than the setpoint pressure, and the pressure pallet travel is not greater than zero, a signal, such as an alarm signal, indicating the pressure pallet is stuck closed, e.g., failing to open, is sent (Block712). Alternatively, when the measured tank pressure is greater than the setpoint pressure and the pressure pallet travel measured is greater than zero, a signal, such as another alarm signal, indicating the pressure pallet is open is sent (Block714).

When the measured tank pressure is determined to be not greater than the setpoint pressure in Block706, and it is determined the pressure pallet travel is greater than zero in Block710, a signal, such as another alarm signal, indicating the pressure pallet is stuck open, e.g., failing to close, is sent in Block716. Alternatively, when the measured tank pressure is determined to be not greater than the setpoint pressure in Block706, and it is determined the pressure pallet travel is not greater than zero in Block710, the method700returns to measuring the tank pressure and the pressure pallet travel in Block704.

In one example, an interface associated with the travel sensor450, for example, or any other interface sends the signal indicating this state of the pressure vacuum relief valve420, such as the signal indicating the pressure pallet is open in Block714, the signal indicating the pressure pallet is stuck closed in Block712and/or the signal indicating the pressure pallet is stuck open in Block716. In another example, the interface sends any of the aforementioned signals of the method700to the base station22that is communicatively coupled to the monitoring system400, for example, to remotely notify an operator. This allows the operator of the monitoring system400for the pressure vacuum relief valve420ofFIGS. 8 and 9to understand the state of the pressure vacuum relief valve420without having to physically inspect the pressure vacuum relief valve420.

Referring now toFIG. 11B, and in another example, the method800may begin with a user or an operator entering a pressure setpoint value for a vacuum pressure of the tank of the pressure vacuum relief value420in Block802. Next, the method800may include measuring the pressure of the tank459of the pressure vacuum relief valve420via the pressure sensor460(FIG. 8) in Block804. In another example, the method may further include measuring the temperature of the tank458via the temperature sensor458. In addition, the method800includes measuring via the travel sensor458(FIG. 8) disposed on the vacuum pallet442a distance traveled by the vacuum pallet442, also in Block804. In block806, the method800further includes determining, via one or more processors, whether the measured tank pressure is less than the setpoint pressure or not less than (e.g., equal to or greater than) the setpoint pressure. In either scenario, the method800then includes determining whether the vacuum pallet travel is greater than zero (Blocks808and810). When the measured tank pressure is less than the setpoint pressure, and the vacuum pallet travel is not greater than zero, a signal, such as an alarm signal, indicating the vacuum pallet is stuck closed, e.g., failing to open, is sent (Block812). Alternatively, when the measured tank pressure is less than the setpoint pressure, and the vacuum pallet travel measured is greater than zero, a signal, such as another alarm signal, indicating the vacuum pallet is open is sent (Block814). When the measured tank pressure is determined to be not less than the setpoint pressure in Block806, and it is determined the vacuum pallet travel is greater than zero in Block810, a signal, such as another alarm signal, indicating the vacuum pallet is stuck open, e.g., failing to close, is sent in Block816. Alternatively, when the measured tank pressure is determined to be not less than the setpoint pressure in Block806, and it is determined the vacuum pallet travel is not greater than zero in Block810, the method800returns to measuring the tank pressure and the vacuum pallet travel in Block804.

In one example, an interface associated with the travel sensor458, for example, or any other interface sends the signal indicating this state of the pressure vacuum relief valve420, such as the signal indicating the vacuum pallet is open in Block814, the signal indicating the vacuum pallet is stuck closed in Block812and/or the signal indicating the vacuum pallet is stuck open in Block816. In another example, the interface sends any of the aforementioned signals of the method800to the base station22that is communicatively coupled to the monitoring system400, for example, to remotely notify an operator. This allows the operator of the monitoring system400for the pressure vacuum relief valve420ofFIGS. 8 and 9to understand the state of the pressure vacuum relief valve420without having to physically inspect the pressure vacuum relief valve420.

Referring now toFIG. 11C, another flow chart of an example method900of the monitoring the pressure vacuum relief valve420ofFIGS. 8 and 9is depicted. Said another way, the monitoring system400of the pressure vacuum relief valve420ofFIGS. 8 and 9may additionally operate according to the method900depicted inFIG. 11C. The method900begins in Block902with measuring tank pressure by the tank pressure sensor460, measuring tank temperature by the tank temperature sensor442, and measuring a distance traveled by one or more of the pressure pallet436or the vacuum pallet442, as described inFIGS. 11A and 11Brelative to methods700and800, respectively). In one example, the measured tank temperature and pressure and distance traveled by the pressure pallet436and/or the vacuum pallet442is transmitted by the interface associated with the travel sensor450,452or the wireless accelerometer454,458to the base station22(FIG. 1).

In Block904, a processor, such as the processor28of the base station22or any other processor associated with the pressure vacuum relief valve420, calculates an instantaneous fluid flow rate value F out of the tank, for example, based on the measured pressure, measured temperature, and distance traveled by the pressure pallet436. More specifically, the fluid flow value F is calculated, via one or more processors, in accordance with the following formula:

Where

PT=Absolute pressure of gas in tank

TT=Absolute temperature of gas in tank

G=specific gravity of gas in tank

Y=pressure pallet distance traveled

K1=Absolute temperature constant

K2=Pressure pallet travel constant

K3=Trim shape constant

In block906, which is similar to block606of the method600inFIG. 10B, the method900further includes estimating a total accumulated fluid flow value F out of the tank during a period of time of an overpressure event, for example. More specifically, the instantaneous fluid flow rate value may be calculated (block904) at a first period of time, such as when the recorded overpressure event began. A second instantaneous fluid flow rate value may then be calculated (block904) at a second period of time, such as when the recorded overpressure event ended. From this data, an estimated total fluid flow F value out of the tank from the first period of time until the second period of time may be calculated. In this manner, the method900incorporates both the state of pressure vacuum relief valve420, e.g., diagnostics relative to whether the pressure vacuum relief valve420is open or closed, and the tank pressure and temperature of the pressure vacuum relief valve420. Said another way, the method900in conjunction with one or more of methods700and800inFIGS. 11A and 11B, respectively, allow an operator to monitor if the pressure vacuum relief valve420is both working properly, e.g., monitor tank temperature and pressure, and opening at the desired pressure because the methods700,800, and900allow simultaneous monitoring of both tank pressure and temperature and if the pressure vacuum relief valve420is opening.

Referring now toFIG. 12, a flow chart of another example method1000of monitoring a relief valve is depicted. The method1000may be implemented, in whole or part, on one or more of the devices or systems such as those depicted in the monitoring system10ofFIG. 1and the monitoring system400of the pressure vacuum relief valve420ofFIG. 9, as explained more below. The method may be saved as a set of instructions, routines, programs, or modules on memory such as base station memory6ofFIG. 1, and may be executed by a processor, such as the base processor28ofFIG. 1.

In block1002, the method1000begins with measuring an acceleration of the pressure pallet436with the first wireless accelerometer454and measuring an acceleration of the vacuum pallet442with the second wireless accelerometer456(FIG. 9). In block1004, the method1000further includes detecting acceleration in a first direction, such as an upward direction or a direction toward an open position, of one or more of the pressure pallet436by the first wireless accelerometer454or the vacuum pallet442with the second wireless accelerometer456.

Upon detecting acceleration of one or more of the pressure pallet436or the vacuum pallet442in block1004, an alarm signal is transmitted in block1006. The alarm signal indicates one or both of the pressure pallet436or the vacuum pallet442has opened, e.g., moves away from the respective valve seats434,440of the pressure pallet436and the vacuum pallet442, respectively (FIG. 9).

In block1008, after one or more of the pressure pallet436or the vacuum pallet442has opened, small vibrations are detected by one or more of the first wireless accelerometer454or the second wireless accelerometer456. The small vibrations indicate the pressure pallet436or the vacuum pallet442is floating on fluid, such as gas, leaving the tank portion of the body458of the pressure vacuum relief valve420, and that the pressure pallet436and/or the vacuum pallet442is still in an open position.

Upon detecting this condition in block1008, another alarm signal is transmitted in block1010. This alarm signal indicates one or both of the pressure pallet436or the vacuum pallet442is still open or in an open position, e.g., moved away from the respective valve seats434,400of the pressure pallet436and the vacuum pallet442, respectively (FIG. 9).

In block1012, the method1000may further include detecting acceleration in a second direction, such as a downward direction or a direction toward the valve seat434,440, of the pressure pallet436and/or the vacuum pallet442indicating that one or more of the pressure pallet436and/or the vacuum pallet442is moving back to a closed position. Said another way, the pressure pallet436and/or the vacuum pallet442is closing and making sealing contact with the valve434,440corresponding to the pressure pallet436and the vacuum pallet442.

In block1014, after one or more of the pressure pallet436or the vacuum pallet442has closed, the method includes detecting an absence of any small vibrations by one or more of the first wireless accelerometer454or the second wireless accelerometer456. The absence of such small vibrations being detected indicates the pressure pallet436or the vacuum pallet442is not floating on fluid, such as gas, leaving the tank portion of the body458of the pressure vacuum relief valve420, and that the pressure pallet436and/or the vacuum pallet442is closed.

Upon detecting one or more of the pressure pallet436and/or the vacuum pallet442is closed in block1014, another alarm signal is transmitted, such as by an interface associated with one or more of the first wireless accelerometer454or the second wireless accelerometer456. This alarm signal indicates one or more of the pressure pallet436and/or the vacuum pallet442is closed. In one example, the alarm signal indicating one or more of the pressure pallet436and/or the vacuum pallet442is closed in block1016may be transmitted via the network24(FIG. 1) to the remotely located base station22(FIG. 1) and stored in the memory26of the base station22, for example, to record and track diagnostic data relating to the operation and performance of the pressure vacuum relief valve420.

In view of the foregoing, it will be appreciated that the various systems10,100,200,300,400and methods500-1000of the present disclosure offer several advantages. Operators of various relief valve systems are able to constantly monitor their systems to instantaneously and remotely know the state of the diagnostic systems to avoid and/or minimize fines relating to any VOCs being emitted to the atmosphere. In addition, systems10,100,200,300and400and corresponding methods500-1000include wireless monitoring that is not intrusive and does not require the measurement of pressure or flow. Because data about one or more of the state of the relief valve, pressure and temperature of the tank, and/or motion and position of various parts of the relief valve may be sent through the wireless network to a monitoring hub, such as the remote base station22(FIG. 1), operators are able to remotely monitor their various relief valve systems and react quickly to any alarms indicating gas is leaving the tank, for example, without having to physically examine the relief valve system.

Said another way, by wirelessly measuring orientation and/or acceleration instead of pressure and flow to understand a current state of the relief valve, the relief valve systems may be monitored without being intrusive to the relief valve system. Such intrusions to the system could add an additional leak path to the system and/or affect performance. Moreover, by enabling the information about the state of the relief valve system to be wirelessly transmitted, users may remotely access and obtain the data about the state of the relief valve system.

Although certain relief valves and relief vents have been described herein in accordance with the teachings of the present disclosure, the scope of coverage of this patent is not limited thereto. On the contrary, while the invention has been shown and described in connection with various preferred embodiments, it is apparent that certain changes and modifications, in addition to those mentioned above, may be made. This patent covers all embodiments of the teachings of the disclosure that fairly fall within the scope of permissible equivalents. Accordingly, it is the intention to protect all variations and modifications that may occur to one of ordinary skill in the art.

In addition, while certain fluid flow equations described above may be used to calculate a fluid flow rate, for example, various other fluid flow equations may alternatively be used and still fall within the scope of the present disclosure. For example, regression could be used to create a polynomial equation that relates the dependent variable (flow) to the independent variables (tank pressure, temperature, and pallet travel/cover angle). Still other methods understood by persons having ordinary skill in the art may one or more of alternatively and/or additionally be used and still fall within the scope of the present disclosure.

As used herein any reference to “one implementation,” “one embodiment,” “an implementation,” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the implementation is included in at least one implementation. The appearances of the phrase “in one implementation” or “in one embodiment” in various places in the specification are not necessarily all referring to the same implementation.

Some implementations may be described using the expression “coupled” along with its derivatives. For example, some implementations may be described using the term “coupled” to indicate that two or more elements are in direct physical or electrical contact. The term “coupled,” however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The implementations are not limited in this context.