Systems and methods for electrical heating trace system management

Abstract

Embodiments of the present invention provide an electric heating trace (EHT) control system for use with a piping system having a pipe and capable of conveying a fluid. The EHT control system includes an EHT circuit for heating the piping system; a temperature sensor that outputs a temperature value; a flow state sensor that outputs a flow state value; and an EHT management system. The EHT management system may include a controller connected to the EHT circuit to selectively energize the EHT circuit. The controller may be connected to the temperature sensor to receive the temperature value, and to the flow state sensor to receive the flow state value. The controller may be configured to execute an EHT management program, the EHT management program including the following steps: receiving the temperature value; receiving the flow state value; and using the temperature value and / or the flow state value to determine whether to energize the EHT circuit.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims priority to U.S. Provisional Application Serial No. 62 / 776,902, filed on December 7, 2018, entitled “Devices and Methods For Electric Heating Trace System Management,” the entire contents of which are incorporated herein by reference. Background Art

[0003] Pipeline systems are often used to transport liquid and / or gaseous products (e.g., petroleum products) over long distances, such as from an extraction point to a processing facility. If the extraction location and / or processing facility is located in a cold weather environment, it may be necessary to provide heating elements or heat traces to maintain the pipeline at a desired temperature to prevent the fluid product from freezing, or temperature sensitive operation to maintain a temperature that allows the fluid product to flow efficiently. The heating element and any associated components may be referred to as an electric heating trace (EHT) circuit.

[0004] Currently, typical EHT circuits are energized or de-energized based on the temperature of the pipe or the temperature of the surrounding environment. When the EHT circuit is energized, the fluid in the pipe can be maintained at a temperature above a temperature set point. The temperature set point can be a temperature that keeps the fluid relatively liquid enough to support fluid flow. If the EHT circuit is not energized for too long, the lower temperature may cause the transported fluid to freeze, become more viscous and / or the fluid may not flow properly. Increased viscosity or phase changes may cause undesirable pressure buildup in the pipe system.

[0005] While leaving the EHT circuit continuously energized can keep the fluid in the pipe above the temperature set point, this approach has drawbacks. For example, the EHT circuit can draw more energy than is required to keep the fluid above the temperature set point. Additionally, if the fluid in the pipe is flowing, the fluid may not require any heating from the EHT circuit to continue flowing. When the EHT circuit is unnecessarily energized, the EHT circuit can waste energy and cause undue wear and tear on the EHT circuit and associated equipment. Summary of the invention

[0006] Embodiments of the present invention provide an EHT control system and method for effectively and cost-effectively managing an EHT circuit while overcoming the above-mentioned deficiencies of previous systems. According to one embodiment of the present invention, an electric heating trace (EHT) control system includes: an EHT circuit, the EHT circuit being used to heat a piping system; a temperature sensor, the temperature sensor outputting a temperature value; a flow state sensor, the flow state sensor outputting a flow state value; and an EHT management system. The EHT management system may include a controller connected to the EHT circuit so as to selectively energize the EHT circuit. The controller may be connected to the temperature sensor to receive the temperature value, and to the flow state sensor to receive the flow state value. The controller may be configured to execute an EHT management program, the EHT management program including the steps of: receiving a temperature value; receiving a flow state value; and determining whether to energize the EHT circuit using the temperature value and / or the flow state value. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram of an electric heating trace (EHT) control system according to some embodiments of the present invention.

[0008] Figure 2 is included in Figure 1 Schematic diagram of the heat trace cables in the EHT control system.

[0009] Figure 3 is included in Figure 1 Schematic diagram of the temperature sensor in the EHT control system.

[0010] Figure 4 is a schematic diagram of an EHT control system according to another embodiment of the present invention.

[0011] Figure 5 is a schematic diagram of an EHT control system according to another embodiment of the present invention.

[0012] Figure 6 is a schematic diagram of an EHT control system according to another embodiment of the present invention.

[0013] Figure 7 is a schematic diagram of an EHT control system according to another embodiment of the present invention.

[0014] Figure 8 is a flow chart of an EHT management system according to one embodiment of the present invention.

[0015] Fig. 9 is a flow chart of an EHT management system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0016] Figures 1 to 3 An electric heating trace (EHT) control system 100 according to one embodiment of the present invention is shown. The EHT control system 100 can be used with a piping system 110, which can also be referred to as a "fluid delivery system." The EHT control system 100 can also include an EHT heating element 120, a temperature sensor 130, a flow state sensor 140, and an EHT management system 150.

[0017] Pipeline system 110 may include pipeline 112 and pump 111. Pipeline system 110 can convey fluid 115, such as oil, water, or any other material that may become more viscous at ambient temperature. Pump 111 may include a pump motor (not shown). Pump 111 can be used to pump fluid 115 throughout pipeline 112. Some applications may not require pump 111 to make fluid flow, such as gravity feeding applications where fluid 115 flows downward. Pipeline 112 can be included in a larger pipeline network. Pipeline system 110 can also include equipment that can store and / or transmit fluid in addition to pipelines, such as storage tanks and / or storage containers. Pipeline system 110 may include accessories, such as adapters, elbows, couplings, unions, threaded joints, reducers, tees, crosses, end caps, electric valves or mechanical valves, flanges, and / or other equipment interconnected with pipelines, storage tanks, storage containers, etc. The piping system 110 may include support structures, such as pipe anchors and / or pipe guides configured to hold the pipe 112 in place and / or prevent rotation of the pipe 112. As will be discussed further below, certain elements of the piping system 110, such as valves, flanges, pipe anchors, and / or pipe guides, may be a significant source of heat loss in the piping system.

[0018] The EHT heating element 120 (also referred to as an EHT heating circuit) can heat the pipe system 110. More specifically, the EHT heating element 120 can heat the pipe 112 so as to transfer heat to the fluid 115. With particular reference to Figure 2 , the EHT heating element 120 may include one or more heat trace cables 122. The heat trace cables 122 (eg, heat trace cables 122A and 122B) may be coupled together in series and / or in parallel such that all heat trace cables 122 are energized or de-energized in unison.

[0019] like Figure 1As shown, the temperature sensor 130 may be placed on the exterior of one of the pipes 112 and coupled to an EHT management system 150 including a controller 152. The temperature sensor 130 may be connected to the controller 152 wirelessly (e.g., using WiFi or Zigbee), or coupled to the controller 152 using a wired connection (e.g., a three-wire connection). In some embodiments, a network of wireless sensors may communicate with the controller 152 using a mesh communication protocol. The temperature sensor 130 may be a resistance thermometer, a resistance temperature detector, or other suitable sensor capable of detecting temperature. The temperature sensor 130 may output a temperature value. The temperature value may be an approximation of the temperature of one or more of the pipes 112. As will be described below in conjunction with Figure 7 As described, in some embodiments, the temperature sensor 130 may be a linear temperature sensor, such as a distributed temperature sensing (DTS) system. The DTS system may include an optical fiber configured to sense temperature at multiple data points along the length of the optical fiber. The optical fiber may be arranged throughout the pipeline system 110. More specifically, the optical fiber may be arranged on the outer surface of the tube 112. In some embodiments, the optical fiber may be arranged in the pipeline 112. In these embodiments, the temperature sensor may include an independent signal controller configured to provide a laser source to the optical fiber and process signals from the optical fiber to determine multiple temperature values ​​at various locations along the optical fiber. Alternatively, the controller 152 may provide the functionality of a signal controller.

[0020] In some embodiments, temperature sensor 130 may be positioned near duct system 110, rather than on the exterior of one of ducts 112, to measure ambient air temperature. Temperature sensor 130 may be positioned such that the temperature sensed by the temperature sensor is correlated to the ambient temperature near duct system 110. Temperature sensor 130 may alternatively be a remote sensor located within a geographic area (e.g., a zip code) of duct system 110. The temperature may be monitored by a weather monitoring service (e.g., AccuWeather). TM ) monitors a remote sensor. In some embodiments, multiple temperature sensors may be used to monitor multiple temperatures at different locations in and / or near the piping system 110.

[0021] like Figure 1 and Figure 3 As shown, the EHT control system 100 may include a plurality of temperature sensors arranged at different locations. For simplicity, elements such as the flow state sensor 140 are not shown. Figure 3As shown, the controller 152 may be coupled to a first temperature sensor 130A disposed on the exterior of a first pipe 112A included in the pipe system 110. The controller 152 may be coupled to a second temperature sensor 130B disposed on the exterior of a second pipe 112B included in the pipe system 110. The first temperature sensor 130A may output a temperature value associated with the temperature of the first pipe 112A, and the second temperature sensor 130B may output a temperature value associated with the temperature of the second pipe 112B.

[0022] The fluid 115 may be different temperatures at different locations within the piping system 110. More specifically, the temperature of the fluid 115 may be lower at locations near elements of the piping system 110 that tend to lose heat more quickly than the pipes 112A to 112C. As described above, valves, flanges, pipe anchors, and / or pipe guides may be more susceptible to heat loss. Valves, flanges, pipe anchors, and / or pipe guides may be referred to as "high heat loss points." Therefore, it may be desirable to place at least one temperature sensor on a pipe near a high heat loss point and / or at a high heat loss point because the fluid 115 may be more susceptible to freezing or falling below a temperature set point at a high heat loss point than at the first pipe 112A and / or the second pipe 112B.

[0023] For example, the second temperature sensor 130B may be placed on the second pipe 112B, near the valve 170, which is coupled to the second pipe 112B and the third pipe 112C. As another example, the third temperature sensor 130C may be placed on the flange 172 coupled to the first pipe 112A and the second pipe 112B, and output a temperature value associated with the temperature of the flange 172. As yet another example, the fourth temperature sensor 130D may be placed on the third pipe 112C, near the pipe anchor 174, which is coupled to the third pipe 112 and is configured to hold the third pipe 112C in place. The fourth temperature sensor 130D may output a temperature value associated with the temperature of the third pipe 112C near the pipe anchor 174. The valve 170 and the flange 172 each have a larger surface area per unit length than the first pipe 112A and the second pipe 112B, and therefore may dissipate more heat than the first pipe 112A and the second pipe 112B. The pipe anchor 174 can conduct heat away from the third pipe 112C and potentially reduce the temperature of the fluid 115. Further, a fifth temperature sensor 130E can be arranged near the pipe system 110 to measure the ambient air temperature. The first pipe 112A can be further coupled to a fluid collection device, such as a holding tank 178.

[0024] The EHT management system 150 may use the temperature values ​​provided by the plurality of temperature sensors (ie, the first temperature sensor 130A, the second temperature sensor 130B, the third temperature sensor 130C, the fourth temperature sensor 130D, and the fifth temperature sensor 130E) to prevent the fluid from freezing or to maintain the fluid 115 above a temperature set point.

[0025] like Figure 1 As shown, the flow state sensor 140 can provide information related to the flow of the fluid 115 to the controller 152. The flow state sensor 140 can be a flow meter, or another suitable device that can measure one or more parameters related to the flow of the fluid 115 (e.g., flow rate). The flow state sensor 140 can also be an ammeter, a speedometer, a motor controller, or another device that can measure one or more parameters related to the operation of the pump 111 and / or the pump motor. The flow state sensor 140 can be a sensor that receives a signal indicating whether the pump 111 and / or the pump motor is on or off. For example, an ammeter coupled to the pump motor of the pump 111 can be used to determine whether the pump 111 is drawing power and is therefore running, which can indicate the flow of the fluid 115. In addition, a motor controller coupled to the pump motor can be used to determine the value of an operating parameter of the pump motor (e.g., motor speed, current drawn, power output, etc.) using a sensor coupled to and / or included in the motor controller.

[0026] The flow state sensor 140 may output a flow state value. The flow state value may be a flow rate, a motor speed, a current value, an electrical power value, a mechanical power value, a Boolean value indicating whether flow is occurring and / or the pump is running (e.g., true) or whether no flow is occurring and / or the pump is not running (e.g., false), or another value related to the flow of the fluid 115 and / or the pump 111 and / or the pump motor. In some embodiments, the flow state sensor 140 may include one or more temperature sensors coupled to the piping system 110, and more specifically to a pipe or tank included in the piping system 110, such as the pipe 112. The flow of the fluid 115 may be determined based on a change in temperature at a particular temperature sensor 130 over a discrete time period or by determining a temperature difference between two or more temperature sensors 130. The change and / or difference in temperature may correspond to how the fluid 115 is moving in the pipe 112. In an embodiment where one or more temperature sensors are used to detect the flow of the fluid 115, the flow state value may be an original temperature value, a temperature difference between two temperature sensors 130, a change in temperature value (ie, a temperature change within a discrete time period), etc.

[0027] In some embodiments, the controller 152 of the EHT management system 150 may be included in a process automation system including at least one processor and at least one memory. In other embodiments, the controller 152 may be an independent controller, such as a microcontroller, which may include at least one processor and at least one memory or a programmable logic controller (PLC). The controller 152 may be configured to execute an EHT management program. The controller 152 may be any controller suitable for receiving input from one or more sensors, devices, or sources of data representing temperature and / or flow. The controller 152 may be coupled to the temperature sensor 130 to receive a temperature value. The controller 152 may be coupled to the flow state sensor 140 to receive a flow state value. The controller 152 may be coupled to the EHT heating element 120 to selectively energize the EHT circuit 120 to heat the pipe system 110. The controller 120 may selectively energize the EHT heating element 120 based on the temperature value and / or the flow state value.

[0028] In some embodiments, the EHT management system 150 and / or the controller 152 can be coupled to a weather monitoring service 180 to receive weather information associated with the geographic area of ​​the pipeline system 110, such as weather forecasts, and raw data such as temperature, atmospheric pressure, humidity, precipitation, wind speed, etc. The EHT management system 150 can be coupled to the weather monitoring service 180 via an Internet connection or other data connection. The weather monitoring service 180 can be an external service such as AccuWeather. TM The EHT management system 150 may determine the cool-down period based on weather information.

[0029] Figure 4 Another embodiment of an EHT control system 100 is shown that includes a process automation system 160. The process automation system 160 can be directly, indirectly, or wirelessly connected to one or more sensors, including a temperature sensor 130 and / or a flow state sensor 140. The sensors 130, 140 can output values, including temperature values ​​or flow state values, to the process automation system 160. The process automation system 160 can be coupled to a controller 152. Any values ​​received by the process automation system 160 can be sent to the controller 152 or read by the controller.

[0030] Figure 5Another embodiment of the EHT control system 100 is shown. The process automation system 160 can be directly, indirectly or wirelessly connected to the temperature sensor 130 and the flow state sensor 140. The temperature sensor 130 and / or the flow state sensor 140 can output values ​​including temperature values ​​or flow state values ​​to the process automation system 160. The process automation system 160 can be coupled to the controller 152. Any values ​​received by the process automation system 160 can be sent to the controller 152 or read by the controller.

[0031] Figure 6 Another embodiment of the EHT control system 100 is shown. The process automation system 160 can be directly, indirectly or wirelessly connected to the temperature sensor 130 and the flow state sensor 140 and the EHT heating element 120. The process automation system 160 can be included in the EHT management system 150. The temperature sensor 130 and / or the flow state sensor 140 can output values ​​including temperature values ​​or flow state values ​​to the process automation system 160. The flow state sensor 140 can be coupled to the pump 111 and configured to output one or more flow state values, including one or more parameter values ​​related to the operation of the pump 111. The flow state sensor 140 can be an ammeter, a speedometer, a motor controller, or any other device that can measure one or more parameter values ​​related to the operation of the pump 111 and / or the pump motor. The flow state sensor 140 can be a sensor that receives a signal indicating whether the pump 111 and / or the pump motor is on or off. The flow state sensor 140 can be a motor controller coupled to the pump motor and configured to output a value of an operating parameter of the pump motor, such as a flow state value, such as a flow rate, a motor speed, a current value, an electrical power value, a mechanical power value, a Boolean value indicating whether flow is occurring and / or the pump is running (e.g., true) or whether no flow is occurring and / or the pump is not running (e.g., false), or other values ​​related to the flow of the fluid 115 and / or the pump 111 and / or the pump motor. The process automation system 160 can selectively power the EHT heating element 120 based on the temperature value and the flow state value.

[0032] Figure 7An additional embodiment of the EHT control system 100 is shown, which includes a linear temperature sensor. The temperature sensor 130 can be a linear temperature sensor, such as a distributed temperature sensing (DTS) system including an optical fiber 184, which is configured to sense temperature at multiple data points along the length of the optical fiber 184. The optical fiber 184 can be arranged throughout the pipeline system 110. More specifically, the optical fiber can be arranged on the outer surface of the tube 112. In some embodiments, the optical fiber can be arranged in the pipeline 112. In some embodiments, the temperature sensor 130 may include an independent signal controller 186, which is configured to provide a laser source to the optical fiber 184 and process the signal from the optical fiber 184 to determine multiple temperature values ​​at various locations along the optical fiber 184 and output the temperature values ​​to the EHT management system 150 and / or the controller 152. In other embodiments, the controller 152 can provide the function of the signal controller 186. Multiple optical fibers can be used in the EHT control system 100.

[0033] about Figures 1 to 7 The elements shown and described may be combined and / or rearranged. For example, any of the sensors (e.g., temperature sensors 130, 130A to 130E and / or flow state sensor 140) may be directly coupled to controller 152 using a wired or wireless connection, or indirectly coupled to controller 152 via process automation system 160. Various flow state sensor types, such as those coupled to pump 110 or to one of the pipes in pipe 112, may be interchangeable. Various temperature sensor types may be used, including linear sensors, such as a DTS system including at least one optical fiber 184 and at least one signal controller 186 and / or a resistance thermometer, resistance temperature detector, or other applicable sensor capable of detecting temperature, which may be used in place of and / or in combination with one another.

[0034] Figure 8 A method for an EHT management system 154 according to some embodiments of the present invention is shown. The EHT management system 154 may be the above-described EHT management system 150. This embodiment may be used in anti-freeze applications. Figure 8 A process including steps 402-418 is shown, which may be stored as computer-readable instructions on a memory of a computing device (e.g., the controller 152 or the process automation system 160). Steps 402-418 may be included in an EHT management program as computer-readable instructions. The EHT management program may be executed by the controller 152 and / or the process automation system 160.

[0035] At 401, the fluid 115 may be flowing and / or above the freezing temperature of the fluid 115. At 402, the EHT management system 154 may receive a temperature value. The temperature value may be received from the temperature sensor 130 and / or the process automation system 160 and may be the temperature of a pipe included in the pipe system 110 or an ambient temperature sensed near the pipe system 110. In embodiments where the temperature sensor is a DTS system, the EHT management system 154 may receive a plurality of temperature values. In some embodiments, at 402, the EHT management system 154 may receive at least two temperature values ​​from a plurality of sensors (e.g., at least two of the temperature sensors 130A to 130E). In some embodiments, the EHT management system 154 may receive one or more temperature values ​​continuously.

[0036] At 404, the EHT management system 154 may receive a flow state value. The flow state value may be received from the flow state sensor 140 and / or the process automation system 160. The flow state value may be a flow rate, a motor speed, a current value, an electrical power value, a mechanical power value, or another value related to the flow of the fluid 115, the pump 111, and / or the pump motor. In some embodiments, the EHT management system 154 may continuously receive the flow state value from the flow state sensor 140 and / or the process automation system 160.

[0037] At 406, the EHT management system 154 may determine whether the temperature value is above a temperature set point. The temperature set point may be a predetermined value related to freezing or viscosity control of the fluid 115, such as a temperature that will maintain a target viscosity level of the fluid 115. In embodiments where the EHT management system 154 receives multiple temperature values ​​(e.g., embodiments using a DTS system as a temperature sensor or receiving at least two temperature values ​​from at least two temperature sensors), the EHT management system 154 may determine whether all temperature values ​​are above the temperature set point. If the EHT management system 154 determines that the temperature value is above the temperature set point or all temperature values ​​are above the temperature set point (i.e., "yes" at 406), the EHT management system 154 may proceed to 408. If the EHT management system 154 determines that the temperature value is not above the temperature set point or not all temperature values ​​are above the temperature set point (i.e., "no" at 406), the EHT management system 154 may proceed to 410.

[0038] At 408, the EHT management system 154 may continue to de-energize or de-energize the EHT circuit 120. The EHT circuit 120 may not need to be energized because the fluid 115 is already flowing and / or because the temperature value is above the temperature set point. In either case, the fluid 115 may not be at risk of freezing, and the EHT circuit 120 does not need to be energized.

[0039] At 410, the EHT management system 154 may determine whether the flow state value is above a flow state set point. The flow state set point may be a value that may indicate the flow of the fluid 115. For example, if the flow state value is a flow value output from a flow meter, the EHT management system 154 may determine whether the flow value is high enough to indicate the flow of the fluid, such as whether the flow state value is above approximately zero volume units per time period. In another example, if the flow state value is related to the operation of the pump 111 and / or pump motor, the EHT management system 154 may determine whether the pump 111 is operating in a state that may indicate the flow of the fluid 115. In this example, if the flow state value is a current value of the pump motor, the EHT management system 154 may determine whether the pump motor is drawing enough current to flow the fluid 115.

[0040] If the EHT management system 154 determines that the flow state value is above the flow state set point (i.e., "yes" at 410), the EHT management system 154 may proceed to 408. If the EHT management system 154 determines that the flow state value is not above the flow state set point (i.e., "no" at 410), the EHT management system 154 may proceed to 412.

[0041] At 412, the EHT management system 154 may start a cooling timer. The cooling timer may wait for a cooling period until the cooling timer expires. The cooling period may be a predetermined value. In some embodiments, the cooling period may be determined at 412 so as to use a current value representing how long it will take for the fluid 115 to reach a critical predetermined value. The cooling period may correspond to the length of time it may take for the temperature of the fluid 115 to reach approximately the freezing temperature of the fluid (e.g., in some embodiments, within about one degree Celsius). The fluid temperature may be higher than the temperature value because the temperature value is based on the temperature of one or more pipes 112. Due to heat loss, the pipe 112 may have a lower temperature than the fluid 115. The cooling period may be determined at least in part by the heat loss characteristics and other thermodynamic properties of the pipe 112, high heat loss points (e.g., valves, flanges, pipe anchors, and / or pipe guides), and the fluid 115 in the pipe 112, or by the difference between the set point and the temperature of the pipe 112 and / or the ambient temperature when the flow of the fluid 115 stops. In some embodiments, the cool down period may be determined at 412 to use a current value that represents how long it may take for the temperature of the fluid 115 to reach a critical predetermined value.

[0042] In some embodiments, the cool-down period may be determined based on one or more of the temperature values ​​received by the EHT management system 154, at least a portion of the weather information received by the EHT management system, and / or heat loss characteristics and / or other thermodynamic properties of the pipe 112, heat loss points (e.g., valves, flanges, pipe anchors, and / or pipe guides), and the fluid 115 in the pipe 112. The EHT management system 154 may determine the difference between the set point and the lowest of any of the temperatures received, and determine, based on the difference, that the cool-down period is equal to the time it takes for the fluid 115 to drop to the critical temperature.

[0043] The EHT management system 154 may also determine a cooling period based on weather information. The EHT management system 154 may use a recent history of weather conditions, including ambient temperature and / or wind speed, to determine the cooling period. For example, if the EHT management system 154 determines that the ambient temperature has been trending downward (i.e., becoming colder) and / or the wind speed is trending upward, the EHT management system 154 may shorten the cooling period. Higher wind speeds may increase heat losses throughout the duct system 110. Alternatively, if the EHT management system 154 determines that the ambient temperature has been trending upward (i.e., becoming hotter) and / or the wind speed is trending downward, the EHT management system 154 may extend the cooling period.

[0044] The EHT management system 154 may also use future predicted weather conditions to determine a cool-down period. More specifically, the EHT management system 154 may determine a cool-down period based on weather forecast data that includes predicted future ambient temperatures and / or wind speeds in the geographic area of ​​the duct system 110. For example, if the weather forecast data includes a predicted ambient temperature that is trending down and / or a wind speed that is trending up, the EHT management system 154 may shorten the cool-down period. Alternatively, if the weather forecast data includes a predicted ambient temperature that is trending up and / or a wind speed that is trending down, the EHT management system 154 may extend the cool-down period. Helping to ensure that the cool-down period is accurate may allow the EHT management system 154 to activate the EHT circuit 120 only when necessary, thereby allowing the EHT control system 100 to operate more efficiently and potentially save energy.

[0045] At 414, the EHT management system 154 may determine whether the cooling timer has expired. In some embodiments, at 414, the EHT management system 154 may periodically (e.g., every half hour in some embodiments) update the cooling timer by determining a cooling period based on the most recent temperature value and / or weather information received. The cooling period may be determined using any of the techniques described above in conjunction with step 412. If the EHT management system 154 determines that the cooling timer has expired (i.e., "yes" at 414), the EHT management system 154 may proceed to 418. If the EHT management system 154 determines that the cooling timer has not expired (i.e., "no" at 414), the EHT management system 154 may proceed to 416.

[0046] At 416, the EHT management system 154 may determine whether the flow state value is above the flow state set point using a method similar to 410. In some embodiments, the flow state value may be the most recent flow state value received by the EHT management system 154. If the EHT management system 154 determines that the flow state value is above the flow state set point (i.e., "yes" at 416), the EHT management system 154 may proceed to 408. If the EHT management system 154 determines that the flow state value is not above the flow state set point (i.e., "no" at 416), the EHT management system 154 may proceed to 418.

[0047] At 418, the EHT management system 154 may power on or begin powering on the EHT circuit 120. The EHT circuit 120 may need to be powered on because the cooling timer has expired and the fluid 115 may be at risk of freezing. The EHT management process 154 may then proceed back to 402.

[0048] Fig. 9 A method for an EHT management system 156 according to another embodiment of the present invention is shown. This embodiment may be used in applications that may require a fluid to be at or above a set point temperature, such as process maintenance or critical temperature maintenance applications. The EHT management system 156 may be the EHT management system 150 described above. Fig. 9 A process including steps 502-516 is shown, which may be stored as computer-readable instructions on a memory of a computing device (e.g., the controller 152 or the process automation system 160). Steps 502-516 may be included as computer-readable instructions in an EHT management program that may be executed by the controller 152 and / or the process automation system 160.

[0049] At 501, the fluid 115 may be flowing and / or above the freezing temperature of the fluid 115. At 502, the EHT management system 156 may receive a temperature value. The temperature value may be received from the temperature sensor 130 and / or the process automation system 160 and may be the temperature of a pipe included in the pipe system 110 or an ambient temperature sensed near the pipe system 110. In embodiments where the temperature sensor is a DTS system, the EHT management system 154 may receive a plurality of temperature values. In some embodiments, at 502, the EHT management system 156 may receive at least two temperature values ​​from a plurality of sensors (e.g., at least two of the temperature sensors 130A to 130E). In some embodiments, the EHT management system 156 may receive one or more temperature values ​​continuously.

[0050] At 504, the EHT management system 156 may receive a flow state value. The flow state value may be received from the flow state sensor 140 and / or the process automation system 160. The flow state value may be a flow rate, a motor speed, a current value, an electrical power value, a mechanical power value, or another value related to the flow of the fluid 115, the pump 111, and / or the pump motor. In some embodiments, the EHT management system 156 may continuously receive the flow state value from the flow state sensor 140 and / or the process automation system 160.

[0051] At 506, the EHT management system 156 may determine whether the temperature value is above a temperature set point. The temperature set point may be a predetermined value related to freezing or viscosity control of the fluid 115, such as a temperature that will maintain a target viscosity level of the fluid 115. In embodiments where the EHT management system 156 receives multiple temperature values ​​(e.g., embodiments using a DTS system as a temperature sensor or receiving at least two temperature values ​​from at least two temperature sensors), the EHT management system 154 may determine whether all temperature values ​​are above the temperature set point. If the EHT management system 156 determines that the temperature value is above the temperature set point (i.e., "yes" at 506), the EHT management system 156 may proceed to 508. If the EHT management system 156 determines that the temperature value is not above the temperature set point (i.e., "no" at 506), the EHT management system 156 may proceed to 510.

[0052] At 508, the EHT management system 156 may continue to de-energize or de-energize the EHT circuit 120. The EHT circuit 120 may not need to be energized because the fluid 115 is already flowing and / or because the temperature value is above the temperature set point. In either case, the fluid 115 may not be at risk of freezing, and the EHT circuit 120 does not need to be energized.

[0053] At 510, the EHT management system 156 may determine whether the flow state value is above a flow state set point. The flow state set point may be a predetermined value that may indicate the flow of the fluid 115. For example, if the flow state value is a flow value output from a flow meter, the EHT management system 156 may determine whether the flow value is high enough to indicate the flow of the fluid, such as whether the flow state value is above approximately zero volume units per time period. In another example, if the flow state value is related to the operation of the pump 111 and / or pump motor, the EHT management system 156 may determine whether the pump 111 is operating in a state that may indicate the flow of the fluid 115. In this example, if the flow state value is a current value of the pump motor, the EHT management system 156 may determine whether the pump motor is drawing enough current to flow the fluid 115.

[0054] If the EHT management system 156 determines that the flow state value is above the flow state set point (i.e., “yes” at 510), the EHT management system 156 may proceed to 508. If the EHT management system 156 determines that the flow state value is not above the flow state set point (i.e., “no” at 510), the EHT management system 156 may proceed to 516.

[0055] At 516, the EHT management system 156 may energize or begin energizing the EHT circuit 120. The EHT circuit 120 may need to be energized in order to heat the pipe 112 and / or the fluid 115 above a temperature set point and / or to prevent the fluid 115 from freezing. The EHT management process 156 may then proceed back to 502.

[0056] Although the present invention has been shown and described in detail in the foregoing drawings and descriptions, the present invention should be considered illustrative rather than restrictive, and it should be understood that only illustrative embodiments of the present invention are shown and described, and all changes and modifications fall within the spirit of the present invention that is desired to be protected. For example, any feature or function of any embodiment in the embodiments disclosed herein can be incorporated into any embodiment in other embodiments disclosed herein. Various features and advantages of the present invention are set forth in the appended claims.

Claims

1. An electric heating trace control system for use with a piping system, the piping system comprising at least one pipe and capable of conveying a fluid; The electric heating trace control system comprises: an electric heating trace (EHT) circuit for heating at least a portion of the piping system; a temperature sensor that outputs a temperature value corresponding to the portion of the piping system; a flow state sensor that outputs a flow state value corresponding to the portion of the piping system; An electric heating trace management system, the electric heating trace management system comprising a controller, the controller being connected to the EHT circuit to selectively energize the EHT circuit; the controller being connected to the temperature sensor to receive the temperature value; and the controller being connected to the flow state sensor to receive the flow state value; the controller being configured to execute an EHT management program, the EHT management program comprising the following steps: receiving the temperature value; receiving the flow state value; discontinuing energizing the EHT circuit when the temperature value is above a predetermined temperature set point; and The EHT circuit is energized when the temperature value is not above a predetermined temperature set point unless the flow state value is above a predetermined flow state set point indicating flow is occurring through the portion of the piping system. 2 . The control system of claim 1 , wherein the conduit system includes a pump, the flow state sensor is coupled to the pump, and wherein the flow state value includes a value of an operating parameter of the pump. 3 . The control system of claim 2 , wherein the operating parameter of the pump includes at least one of a motor speed, a current value, or a Boolean value indicating whether the pump is running.

4. The control system of claim 1 , wherein the EHT management routine further comprises receiving a second temperature value from a second sensor, and wherein determining not to energize the EHT circuit comprises: determining that the temperature value is not greater than the predetermined temperature set point; determining that the second temperature value is not greater than the predetermined temperature set point; as well as It is determined that the flow state value is above the predetermined flow state set point.

5. The control system of claim 1, wherein the flow state sensor is connected to a process automation system, the process automation system also coupled to the controller. 6 . The control system of claim 1 , wherein the EHT circuit comprises at least two heat trace cables connected together and configured to be energized or de-energized in unison.

7. The control system of claim 1, wherein the temperature value is an ambient air temperature of the duct system. 8 . The control system of claim 1 , wherein the temperature sensor is coupled to a pipe included in the pipe system, and the temperature value is a temperature of the pipe.

9. The control system of claim 1, wherein the EHT management program further comprises the following steps: determining that the temperature value is not greater than the predetermined temperature set point; determining that the flow state value is not above a predetermined flow state set point; starting a cooldown timer configured to wait until a cooldown period expires; determining that the cooling-off period has expired; and The EHT circuit is powered on in response to determining that the cool down period has expired.

10. An electric heating trace control system for use with a fluid delivery system, the electric heating trace control system comprising at least one processor and at least one memory, the at least one memory comprising instructions that, when executed by the at least one processor, cause the electric heating trace control system to: receiving a temperature value corresponding to a portion of the fluid delivery system; receiving a flow state value corresponding to the portion of the fluid delivery system; determining that the temperature value is not greater than a predetermined temperature set point; Once it is determined that the temperature value is not higher than the predetermined temperature set point, determining that the flow state value is not higher than a predetermined flow state set point; Upon determining that the flow state value is not above the predetermined flow state set point, starting a cooling timer, the cooling timer being configured to wait for a cooling period; determining that the cooling-off period has expired; and Unless the flow state value is above the predetermined flow state set point during the cool down period indicating flow is occurring through the portion of the fluid delivery system, energizing the electrical heating trace circuit in response to determining that the cool down period has expired.

11. The control system of claim 10, wherein the cool-down period is the time it will take for the temperature of the fluid to reach a critical predetermined value.

12. The control system of claim 11, wherein the critical predetermined value is approximately the freezing temperature of the fluid.

13. The control system of claim 10, wherein the cool down period is determined based on the temperature value.

14. The control system of claim 13, wherein the at least one memory further comprises instructions for receiving weather information, and wherein the cool down period is determined based on the weather information.

15. The control system of claim 13, wherein the cool down period is determined based on heat loss characteristics of the fluid delivery system.

16. A method for controlling an electrical heating trace circuit coupled to a fluid delivery system and comprising at least one heating cable, the method comprising: receiving a temperature value corresponding to a portion of a fluid delivery system capable of delivering a fluid; receiving a flow state value corresponding to the portion of the fluid delivery system; determining that the temperature value is not greater than a predetermined temperature set point; Once it is determined that the temperature value is not higher than the predetermined temperature set point, determining that the flow state value is not higher than a predetermined flow state set point; Upon determining that the flow state value is not above the predetermined flow state set point, starting a cooling timer, the cooling timer being configured to wait for a cooling period; determining that the cooling-off period has expired; and Unless the flow state value is above the predetermined flow state set point during the cool down period indicating flow is occurring through the portion of the fluid delivery system, energizing the electrical heating trace circuit in response to determining that the cool down timer has expired.

17. The method of claim 16, wherein the flow state value is a value of an operating parameter of a pump included in the fluid delivery system. The method of claim 16 , wherein the temperature value is an ambient temperature of the fluid delivery system.

19. The method according to claim 16, further comprising: determining that the temperature value is not greater than the predetermined temperature set point; determining that the flow state value is above the predetermined flow state set point; as well as In response to determining that the flow state value is above the predetermined flow state set point, energizing the electrical heating trace circuit is stopped.

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