Powering sensors using existing process control loops

Abstract

Hardware configured to collect data on a process line. These configurations may include devices that can be connected to an existing process control network, such as a 4-20 mA control loop. These devices may include a rechargeable power source, such as a supercapacitor. This power source can power sensors or similar hardware that reside in proximity to control valves or other devices on the process line. The sensors may require power levels for short periods of time that significantly exceed those available from the 4-20 mA current loop network. As an added benefit, the circuit may find use in allowing the power source to store or recharge power at periodic intervals to ensure that the sensors can collect data periodically throughout the life of the control valve.

Description

[Technical Field]

[0001] Industrial process facilities use networks to relay control signals from a central process controller to many process devices. These networks may use a variety of standards to transmit data and information. One of the oldest and most widely used standards across multiple industries is the 4-20 mA current loop. This standard has provided reliable communication over a relatively simple two-wire cable since the 1950s. However, while uncomplicated, the infrastructure only provides a fixed, limited power supply at process devices. This limitation can hinder efforts to expand functionality or add new hardware near controlled devices, as any new features may require more power than is available through the existing network structure. As a result, operators are reluctant to adopt any equipment that requires investing in new infrastructure to provide adequate power locally to process devices, even if it would be beneficial. Summary of the Invention

[0002] The subject matter of this disclosure relates to improvements that allow operators to add new hardware onto existing industrial networks. Of particular interest are embodiments of sensing hardware that can reside in proximity to process devices on a process line, for example. This hardware can draw power from the existing network infrastructure to store or recharge a local power source. Sensors can then draw power from this local power source. This design eliminates the need for any additional power infrastructure outside of the connections already available on the process line or industrial facility. This feature is beneficial because it allows operators to adopt new, more robust data collection without having to invest in separate power resources such as electrical cables, batteries, or renewable energy sources (e.g., solar). [Brief explanation of the drawings]

[0003] This specification makes reference to the following drawings: [Figure 1] 1 depicts a schematic diagram of an exemplary embodiment of hardware for use in proximity to a process device. [Figure 2] 2 illustrates a schematic diagram of one embodiment of the hardware of FIG. 1. [Figure 3] 2 illustrates a schematic diagram of one embodiment of the hardware of FIG. 1. [Figure 4] 2 depicts an example schematic diagram of the hardware of FIG. 1 in the form of a test circuit for characterization of a supercapacitor's ability to cyclically power a 1.4 W methane sensor. [Figure 5] 5 depicts plots of data illustrating the operation of the text circuit of FIG.

[0004] These drawings and any descriptions herein represent examples that may disclose or describe the invention. The examples, including the best mode, enable one skilled in the art to practice the invention, including making and using any device or system and performing any incorporated methods. The drawings may use like reference numerals to indicate the same or corresponding elements. The methods are merely exemplary and may be modified, for example, by reordering, adding, removing, and / or changing individual steps or stages. The specification may identify such stages, as well as any parts, components, elements, or functions, in the singular using the word "a" or "an." However, this should not exclude the plural of such designation unless the specification expressly lists or describes such exclusion. Similarly, reference to "one embodiment" or "one implementation" should not exclude the existence of additional embodiments or implementations that also incorporate the recited features. DETAILED DESCRIPTION OF THE INVENTION

[0005] Next, we will describe features of the embodiments shown in the above figures. These features may periodically consume energy in a local storage device to power sensors or other data collection devices found adjacent or proximate to process devices such as control valves. These new sensors can provide complementary data to already installed sensors mounted on nearby process devices. Other embodiments are within the scope of this disclosure.

[0006] The proposed design may find use in many process applications due to the commonly found use of 4-20 mA control loops. Thermal power plants utilize 4-20 mA control loops to control the flow of fuel gas, feedwater, steam, or cooling water to turbines, boilers, evaporators, and other equipment. Natural gas pipeline controls use 4-20 mA control loops to manage variable gas flows to power plants, residential communities, or industrial facilities such as refineries. Most, if not all, of these facilities use control valves with position controls that require, in part, control signals from a central platform such as a central PLC or distributed control system ("DCS"). These platforms prefer 4-20 mA control loops for their simplicity and stability. However, an added advantage is that the proposed design can leverage the same architecture to provide rechargeable power that can power new hardware, including the sensors disclosed herein.

[0007] 1 depicts a schematic diagram of an exemplary embodiment of additional hardware 100. This example is part of a distribution network 102 that moves material 104 through a conduit 106. A flow control 108 may be configured in-line with the conduit 106. The flow control 108 may include a valve assembly having a valve 110 coupled to an actuator 112. A controller 114 may be connected to the actuator 112. The controller 114 also connects to a process control system 116, shown here with a process controller 118 and a data exchange network 120. As also shown, the additional hardware 100 may include a sensor device 122 that connects to the data exchange network 120. The sensor device 122 may include a sensor 124 coupled to a rechargeable power source 126.

[0008] Generally, the additional hardware 100 is configured to provide additional data or functionality. These configurations may include devices capable of collecting information for diagnostics, such as device-level or process line analysis. These devices may recover power from local storage, which may replenish or recharge during normal operation of the process line. However, devices according to the present disclosure may also draw power from available sources. This feature is beneficial because it allows operators to avoid the need for capital investment in additional hardware.

[0009] The distribution network 102 may be configured to deliver or move resources. These configurations may find use in a wide range of applications. In this example, the material 104 may include fuel gas, steam, feedwater, or cooling water, although the material 104 may also include other gases, liquids, solids, or mixtures. The conduits 106 may often include pipes or pipelines that connect to pumps, turbines, condensers, boilers, etc. In some implementations, these pipes may form an intricate network that connects to tanks or reservoirs within industrial infrastructure or even to residential or commercial facilities.

[0010] Flow control 108 may be configured to regulate flow throughout this infrastructure. These configurations may include devices that connect to conduits 106. For example, valve assemblies may embody control valves, and valves 110 may have a closure member that moves relative to a valve seat. Examples of closure members may embody plugs, balls, butterflies, etc. Actuators 112 may manage the position of the closure member. This device may be operated pneumatically or hydraulically, as well as with an electric (or electrical) motor. Controller 114 may include devices capable of providing signals to actuators 112 for this purpose. These devices may be capable of exchanging and processing signals, for example, to provide pneumatic or "instrument" air signals to pneumatic actuators and electrical feedback signals.

[0011] 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 devices on the process line to ensure that material flows according to the process. The process controller 118 may generate control signals having operating parameters that describe or define the operation of the flow control 108 for this purpose. These signals may be transmitted over a data exchange network 120. In one implementation, the operating parameters may define a command position that the controller 114 processes to generate a signal to the actuator 112. The parameters of the instrument air signal, such as pressure or flow rate, may depend in large part on the command position of the valve assembly 110.

[0012] 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 standard 4-20 mA current loops, which are common in many industries for providing communication between DCSs and process devices (such as flow control 108). This loop architecture is ideal for long distances because current signals do not degrade like voltages. This architecture is also less sensitive to background electrical noise.

[0013] The sensor devices 124 may be configured to collect data at or near the device over a 4-20 mA control loop. These configurations may include devices that measure conditions or parameters and generate data that the controller 114 or DCS 118 can use to maintain or optimize the performance of the process line. The devices may respond to changes in temperature, pressure, humidity, vibration, wind speed, etc.

[0014] The rechargeable power supply 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 can include a battery; however, in one embodiment, a supercapacitor or multiple supercapacitors (or "capacitor bank") are connected to the current loop to store energy. Periodic discharge from the capacitor can power adjacent sensors. This feature avoids the need for additional hardware or power infrastructure to provide sufficient power to support these expanded data collection devices.

[0015] FIG. 2 depicts a schematic diagram of one embodiment of additional hardware 100. This embodiment connects sensor 124 in series with rechargeable power source 126. Electronics 128 can help implement this proposed design. Electronics 128 can include control circuitry 130 that can control the discharge of power source 126 to energize sensor 124. This feature can change the state of sensor 124, for example, from "on" to "off" and vice versa. This level of control avoids continuous draw from power source 126. In one implementation, protection circuitry 132 can be inserted between connection 134 connecting sensor 124 to loop 122 and available power source P. Circuitry 132 can be configured to prevent overvoltage, voltage reversal, or overcurrent events that could damage other components in the design. Loop 122 can also include resistors 136, 138, or similar hardware. Resistor 136 can convert voltage to current. The resistor 138 may limit the current to the sensor 124 .

[0016] FIG. 3 depicts a schematic diagram of one embodiment of hardware 100. Rechargeable energy source 126 may embody a supercapacitor 140. A signal module 142 may be coupled to supercapacitor 140. This device may facilitate the use of HART signals; however, this disclosure contemplates that signal module 142 may also accommodate other types of industry-level control signal modalities. In one implementation, the design may include a transformer 144. Windings 146, 148 of transformer 144 may be coupled to signal module 142 and current loop 122. This configuration may enable hardware 100 to transmit or receive HART signals. Bidirectional exchange of HART signals may serve to power multiple sensors from supercapacitor 140.

[0017] FIGS. 4 and 5 provide information regarding an embodiment of the hardware 100 for testing purposes. FIG. 4 illustrates a schematic diagram of a test circuit used to characterize one embodiment of the supercapacitor 140 of FIG. 3. This test circuit operates with a 3.6 mA charge current and a 1 W pulse load. The supercapacitor 140 may embody a 60 F device with a maximum voltage of 2.7 V and an operating temperature of −40° C. to 85° C. This device can provide energy to operate the sensor 124, here a methane sensor, for 30 seconds every two hours. FIG. 5 illustrates a plot of the charge time of a pair of 60 F devices as seen on a circuit powering a methane sensor using 1.4 W for 84 seconds on a 4-20 mA loop. In operation, one implementation of the additional hardware 100 can automatically switch from a “charge” mode to a “discharge” mode in response to the storage voltage of the supercapacitor 140. The discharge mode may, for example, activate the booster inverter to provide (or generate) power of, for example, 7 volts to energize the methane sensor (including its auxiliary sensor heater or electronics, if desired). The charge mode may deactivate certain electronics, such as the booster inverter, to allow charge storage from the 4-20 mA loop.

[0018] In light of the above, improvements herein expand functionality on process lines. Embodiments utilize existing signal infrastructure, such as a 4-20 mA control loop, to store charge for use with sensors. This feature avoids capital expenditures, such as installing dedicated power cables for new sensors, adding dedicated batteries for sensors, or installing renewable sources (such as solar PV cells). Instead, the use of supercapacitor storage facilitates plug-and-play capabilities that can expand data collection to include other data that may be beneficial for online diagnostics, which can improve cost of ownership for operators, reduce downtime, and increase line efficiency for operators.

[0019] The following examples illustrate embodiments contemplated within the scope and spirit of the present disclosure, including certain specific elements or items (one or more of which may be combined with other elements and items). This scope includes and is contemplated by those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they have equivalent structural elements that differ insignificantly from the literal language of the claims.

Claims

1. A sensor device, A sensor, a rechargeable energy source coupled to the sensor and providing a signal to activate the sensor; and circuitry that couples the rechargeable energy source to an industrial control loop.

2. The sensor device of claim 1 , further comprising a protection circuit interposed between the sensor and the industrial control loop.

3. The sensor device of claim 1 , further comprising a circuit interposed between the sensor and the industrial control loop to prevent overvoltage of the sensor.

4. The sensor device of claim 1 further comprising a circuit interposed between the sensor and the industrial control loop that prevents overcurrent in the sensor.

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

7. a signal module coupled to the rechargeable energy source; The sensor device of claim 1 , wherein the signal module is configured to charge the rechargeable energy source from a HART signal.

8. a signal module coupled to the rechargeable energy source; a transformer coupled to the signal module and the industrial control loop; The sensor device of claim 1 , wherein the signal module is configured to charge the rechargeable energy source from a HART signal.

9. The sensor device of claim 1 , wherein the circuitry 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. 1. A system comprising: Valve and an actuator coupled to the valve; hardware coupled to the actuator, the hardware comprising: and hardware comprising a sensor device having a sensor coupled to a supercapacitor.

12. 12. The system of claim 11, further comprising a circuit that couples to and charges the supercapacitor using a 4-20 mA signal.

13. 12. The system of claim 11, further comprising a circuit that couples to and charges the supercapacitor using a HART signal.

14. 12. The system of claim 11, further comprising circuitry that activates the sensor at periodic intervals to draw power from the supercapacitor.

15. The system of claim 11 , further comprising circuitry for changing the state of the sensor between on and off, the sensor drawing power from the supercapacitor in the on state.

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

17. 1. A method comprising: directing a signal from an industrial control loop to a supercapacitor; and drawing power from a rechargeable energy source to power the sensor.

18. further comprising turning the sensor on and off; 18. The method of claim 17, wherein the signal recharges the supercapacitor when the sensor is off.

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

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

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