Powering sensors with existing process control loops

Abstract

Hardware configured to collect data on a process line. These configurations may include devices that can be connected to existing process control networks, such as 4-20 mA control loops. These devices may include a rechargeable power supply, such as a supercapacitor. The power source may power a sensor or similar hardware located near a control valve or other device on the process line. The sensor may need for a short time to significantly exceed a power level available from a 4-20 mA current loop network. As an additional benefit, the circuitry may be used to allow the power source to store power or recharge at periodic intervals to ensure that the sensor may collect data periodically during the life of the control valve.

Description

Background Art

[0001] Industrial process facilities use networks to relay control signals from a central process controller to many process devices. These networks can use various standards to transmit data and information. One of the oldest and most widely used standards in multiple industries is the 4-20mA current loop. Since the 1950s, this standard has provided reliable communication through a relatively simple two-wire cable. However, despite its simplicity, the infrastructure only provides a fixed, limited power supply at the process device. This limitation may hinder efforts to expand functionality or add new hardware near the controlled device, because any new feature may require power that exceeds the power available through the existing network structure. Therefore, even if it is beneficial, operators do not like to adopt any equipment that requires them to invest in new infrastructure to provide sufficient power locally at the process device. Summary of the invention

[0002] The subject matter of the present disclosure relates to improvements that allow operators to add new hardware on existing industrial networks. Of particular interest is the implementation of sensing hardware that can be located, for example, near process equipment on a process line. The hardware can draw power from the existing network infrastructure to store or recharge local power. The sensor can then draw power from the local power supply. This design eliminates the need for any additional power infrastructure beyond the connections already available on the process line or industrial facility. This feature is beneficial because operators can adopt new, more robust data collection without investing in separate power resources such as cables, batteries, or renewable energy sources (e.g., solar energy). BRIEF DESCRIPTION OF THE DRAWINGS

[0003] This specification refers to the following drawings:

[0004] Figure 1 A schematic diagram showing an exemplary embodiment of hardware for use in proximity to a process plant;

[0005] Figure 2 Shows Figure 1 A schematic diagram of an example of hardware;

[0006] Figure 3 Shows Figure 1 A schematic diagram of an example of hardware;

[0007] Figure 4 The test circuit is shown as Figure 1 A schematic diagram of an example of hardware for characterizing the ability of a supercapacitor to periodically power a 1.4W methane sensor; and

[0008] Figure 5 Shows the description Figure 4 A data graph of the operation of the test circuit.

[0009] These figures and any description herein represent examples that may disclose or explain the present invention. The examples include the best mode and enable any person skilled in the art to practice the present invention, including making and using any device or system and performing any combined method. The accompanying drawings may use similar reference numerals to represent the same or corresponding elements. The method is exemplary only and may be modified by, for example, reordering, adding, deleting and / or changing individual steps or stages. The specification may utilize the words "one" or "a kind" to identify such stages and any part, component, element or function; however, this should not exclude a plurality of any such designations unless the specification explicitly states or explains such exclusion. Similarly, reference to "one embodiment" or "a specific implementation" should not exclude the existence of other embodiments or specific implementations that also incorporate the features. DETAILED DESCRIPTION

[0010] Features of the embodiments shown in the above figures will now be discussed. These features can periodically consume energy in a local storage device to power sensors or other data collection devices adjacent to or near process equipment (such as control valves). These new sensors can provide data that is complementary to sensors already installed on nearby process equipment. Other embodiments are within the scope of this disclosure.

[0011] Due to the common use of 4-20mA control loops, the proposed design can be used in many process applications. Thermal power plants utilize 4-20mA control loops to control the flow of fuel gas, feed water, steam or cooling water to turbines, boilers, evaporators and other equipment. Natural gas pipeline control uses 4-20mA control loops to manage variable gas flows to power stations, residential communities or industrial facilities such as refineries. Most, if not all, of these facilities use control valves with position control, which in part require control signals from a central platform such as a central PLC or distributed control system ("DCS"). These platforms support 4-20mA control loops due to their simplicity and stability. However, an additional benefit is that the proposed design can utilize the same architecture to provide rechargeable power that can power new hardware, including the sensors disclosed herein.

[0012] Figure 1A schematic diagram of an exemplary embodiment of additional hardware 100 is shown. This example is a portion of a distribution network 102 that moves a material 104 through a conduit 106. A flow controller 108 can be built inline with the conduit 106. The flow controller 108 can include a valve assembly having a valve 110 coupled to an actuator 112. A controller 114 can be coupled to the actuator 112. The controller 114 is also coupled to a process control system 116, shown here as having a process controller 118 and a data exchange network 120. As also shown, the additional hardware 100 can include a sensor device 122 coupled to the data exchange network 120. The sensor device 122 can include a sensor 124 coupled to a rechargeable power source 126.

[0013] Broadly, the additional hardware 100 is configured to provide additional data or functionality. These configurations may include devices that can collect information for diagnostics, such as for device-level or process line analysis. These devices may draw power from local storage devices that can be replenished or recharged during normal operation of the process line. However, devices according to the present disclosure may also draw power from available power sources. This feature is beneficial because the operator can avoid the need for capital investment in additional hardware.

[0014] Distribution network 102 may be configured to deliver or move resources. These configurations may find use in a wide variety of applications. For this example, material 104 may include fuel gas, steam, feed water, or cooling water; however, material 104 may also include other gases, liquids, solids, or mixtures. Conduits 106 may include pipes or lines that are often connected to pumps, turbines, condensers, boilers, etc. In some implementations, these pipes may form a complex network that connects to tanks or reservoirs in industrial infrastructure or even to residential or commercial facilities.

[0015] The flow controller 108 may be configured to regulate flow throughout the infrastructure. These configurations may include devices connected to the conduit 106. For example, the valve assembly may be embodied as a control valve, wherein the valve 110 may have a closing member that moves relative to the valve seat. Examples of closing members may be embodied as plugs, balls, butterfly pieces, etc. Actuator 112 may manage the position of the closing member. The device may operate pneumatically or hydraulically, as well as operate with an electric (or electrical) motor. Controller 114 may include devices that can provide signals to actuator 112 for this purpose. These devices may be capable of exchanging and processing signals, such as providing pneumatic or "instrument" air signals to pneumatic actuators and providing electrical feedback signals.

[0016] The process control system 116 may be configured to exchange data with the controller 114. These configurations may form a control network (or "distributed control system" or "DCS") that maintains the operation of all equipment on the process line to ensure that materials flow according to the process. The process controller 118 may generate control signals with operating parameters that describe or define the operation of the flow controller 108 for that purpose. These signals may be transmitted over the data exchange network 120. In one specific implementation, the operating parameters may define the command positions that the controller 114 processes to generate its signals to the actuator 112. Parameters for the instrument air signal, such as pressure or flow rate, may depend to a large extent on the command position of the valve assembly 110.

[0017] The data exchange network 122 can be configured to provide data and power to devices throughout a facility or industrial infrastructure. These configurations can utilize a standard 4-20 mA current loop that is prevalent in many industries to provide communication between a DCS and process devices such as flow controllers 108. The structure of this loop is ideal for long distances because the current signal does not degrade like the voltage. The structure is also less sensitive to background electrical noise.

[0018] Sensor devices 124 may be configured to collect data at or near the device across a 4-20 mA control loop. These configurations may include devices that measure conditions or parameters, thereby generating data that the controller 114 or DCS 118 may utilize to maintain or optimize the performance of the process line. The device may respond to changes in temperature, pressure, humidity, vibration, wind speed, etc.

[0019] The rechargeable power source 126 can be configured to power any additional sensors. These configurations can include devices that can utilize a current signal on a 4-20 mA current loop to maintain power output. The device may include a battery; however, in one example, a supercapacitor or multiple supercapacitors (or "capacitor bank") are connected to the current loop to store energy. Periodic discharges from the capacitors can power adjacent sensors. This feature avoids the need for additional hardware or power infrastructure to provide power sufficient to support these expanded data acquisition devices.

[0020] Figure 2A schematic diagram of an example of additional hardware 100 is shown. This example connects a sensor 124 in series with a rechargeable power source 126. Electronics 128 can help implement this proposed design. Electronics 128 can include control circuitry 130, which can control the discharge of power source 126 to energize sensor 124. This feature can change the state of sensor 124, such as from "on" to "off" and vice versa. This level of control avoids continuous drawing from power source 126. In one specific implementation, a protection circuit 132 can be inserted between connections 134, which connect sensor 124 to loop 122 and available power source P. Circuit 132 can be configured to prevent overvoltage, voltage reversal, or overcurrent events that may damage other components in the design. Loop 122 can also include resistors 136, 138, or similar hardware. Resistor 136 can convert voltage into current. Resistor 138 can limit the current to sensor 124.

[0021] Figure 3 A schematic diagram of an example of hardware 100 is shown. The rechargeable energy source 126 may be embodied as a supercapacitor 140. A signal module 142 may be coupled to the supercapacitor 140. The device may facilitate the use of HART signals; however, the present disclosure contemplates that the signal module 142 may also accommodate other types of industrial-grade control signal modalities. In one specific implementation, the design may include a transformer 144. Windings 146, 148 of the transformer 144 may be coupled to the signal module 142 and the current loop 122. This arrangement may allow the hardware 100 to transmit or receive HART signals. The bidirectional exchange of HART signals may be used to power multiple sensors from the supercapacitor 140.

[0022] Figure 4 and Figure 5 Information is provided on examples of testing performed on hardware 100 for qualification purposes. Figure 4 Shown is a characterization of Figure 3 Schematic diagram of an example test circuit of a supercapacitor 140. The test circuit operates at a charge current of 3.6 mA and a pulse load of 1 W. The supercapacitor 140 may be embodied as a 60 F device with a maximum voltage of 2.7 V and an operating temperature from -40 C to 85 C. The device may provide energy to operate the sensor 124 (here a methane sensor) for thirty (30) seconds every two (2) hours. Figure 5A graph depicting charging time for a pair of 60F devices found on a circuit powering a methane sensor using 1.4W for eighty-four (84) seconds on a 4-20mA loop. In operation, one implementation of the add-on hardware 100 may automatically switch from a "charge" mode to a "discharge" mode in response to the stored voltage of the supercapacitor 140. The discharge mode may, for example, activate a boost converter to provide (or generate) seven (7) volts of power, for example, to energize the methane sensor (including its auxiliary sensor heater or electronics, if necessary). The charge mode may deactivate certain electronics, such as the boost converter, to allow charge to be stored from the 4-20mA loop.

[0023] In view of the foregoing, the improvements herein extend functionality on the process line. The embodiments utilize existing signal infrastructure, such as 4-20mA control loops, to store charge for use at the sensor. This feature avoids capital expenditures such as laying new sensor-specific power cables, adding sensor-specific batteries, or installing regenerative sources such as solar PV cells. Instead, the use of supercapacitor storage facilitates plug-and-play capabilities that extend data collection to include other data that may be beneficial for online diagnostics, which may improve the operator's cost of ownership, reduce downtime, and increase the operator's line efficiency.

[0024] The following examples include certain elements or clauses, one or more of which may be combined with other elements and clauses to describe embodiments contemplated within the scope and substance of the present disclosure. The scope may include and contemplate other examples that occur to those skilled in the art. If such other examples have structural elements that are indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are indistinguishable from the literal language of the claims, these other examples are intended to fall within the scope of the claims.

Claims

1. A sensor device, comprising: sensor; a rechargeable energy source coupled to the sensor and providing a signal to activate the sensor; and Circuitry for coupling the rechargeable energy source to an industrial control loop.

2. The sensor device according to claim 1, further comprising: A protection circuit is interposed between the sensor and the industrial control loop.

3. The sensor device according to claim 1, further comprising: A circuit interposed between the sensor and the industrial control loop to prevent overvoltage on the sensor.

4. The sensor device according to claim 1, further comprising: A circuit is interposed between the sensor and the industrial control loop to prevent overcurrent on the sensor.

5. The sensor device of claim 1, wherein the circuit is configured to conduct a signal from a 4-20 mA control loop to charge the rechargeable energy source.

6. The sensor device of claim 1, wherein the circuit is configured to conduct a signal from a HART control loop to charge the rechargeable energy source.

7. The sensor device according to claim 1, further comprising: a signal module coupled to the rechargeable energy source, Wherein the signal module is configured to charge the rechargeable energy source from the HART signal.

8. The sensor device according to claim 1, further comprising: a signal module coupled to the rechargeable energy source; A transformer, the transformer is connected to the signal module and the industrial control loop, Wherein the signal module is configured to charge the rechargeable energy source from the HART signal.

9. The sensor device of claim 1, wherein the circuit activates the sensor at periodic intervals to draw power from a supercapacitor.

10. The sensor device of claim 1, wherein the rechargeable energy source is a supercapacitor.

11. A system comprising: valve; an actuator coupled to the valve; and Hardware, the hardware is connected to the actuator, the hardware includes: A sensor device having a sensor coupled to a supercapacitor.

12. The system according to claim 11, further comprising: A circuit is provided to couple the supercapacitor to charge using a 4-20 mA signal.

13. The system of claim 11, further comprising: A circuit is provided for coupling the supercapacitor to be charged using the HART signal.

14. The system of claim 11, further comprising: A circuit activates the sensor at periodic intervals to draw power from the supercapacitor.

15. The system of claim 11, further comprising: A circuit changes the state of the sensor between on and off, wherein the sensor draws power from the supercapacitor in the on state.

16. The system of claim 11, wherein the sensor comprises a methane sensor.

17. A method comprising: Directing signals from industrial control loops to supercapacitors; Power is drawn from the rechargeable energy source to power the sensor.

18. The method according to claim 17, further comprising: Turning the sensor on and off, Wherein when the sensor is turned off, the signal recharges the supercapacitor.

19. The method of claim 17, wherein the signal is a 4-20 mA signal.

20. The method of claim 17, wherein the signal is a HART signal.

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