WIRELESS MODULES WITH POWER CONTROL CIRCUITS FOR HEAT TRACE SYSTEM

• US 20160245447A1
• Filed: 02/19/2015
• Published: 08/25/2016
• Est. Priority Date: 02/19/2015
• Status: Active Grant

• Current Assignee: Chromalox Incorporated (Spirax-Sarco Engineering PLC)
• Original Assignee: Chromalox Incorporated (Spirax-Sarco Engineering PLC)
• Inventors: Crombie, Mark, Heiligenstein, Adam
• Granted Patent: US 9,651,184 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F16L 53/38 using elongate electric heating elements, e.g. wires or ribbons
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H05B 1/0244 Heating of fluids H05B1/0247 takes precedence
• CPC Class Codes: H05B 1/0291 Tubular elements

Abstract

A heat trace system heats (or maintains the temperature of) vessels of a piping system. Heat trace cables are connected to power control devices in respective wireless modules such that when the power control device in a wireless module is on, the heat trace cable connected to that wireless module conducts current, and thereby heats the vessel contacting the heat trace cable. The wireless module receives control commands for controlling its power control device wirelessly from the main power distribution and control system via a wireless communication network. A wireless module can include a sensor, where the wireless module report backs conditions sensed by the sensor to the main power distribution and control system via the wireless network. The main power distribution and control system can use that information in its control loops to control the switching of the power control devices in the wireless modules, to thereby control whether the associated heat trace cable conducts current or not, to thereby control the temperature at the vessel that is heated by the heat trace cable.

Claims

1. A heat trace system for heating vessels of a piping system, the heat trace system comprising:

a main power distribution and control unit that comprises;

an electrical power source;

a wireless communication gateway;

a front-end controller in communication with wireless communication gateway;

a plurality of heat trace cables, wherein each heat trace cable is adjacent to a vessel of the piping system; and

a plurality of wireless field devices, wherein each of the plurality of wireless field devices comprises;

a power control device having an input connected to the electrical power source of the main power distribution and control unit, and having an output connected to an associated heat trace cable of the plurality of heat trace cables, such that when the power control device is ON, the associated heat trace cable conducts current from the electrical power source of the main power distribution and control unit;

an RF module for communicating with the wireless communication gateway of the main power distribution and control unit via a wireless communication network; and

a field device controller in communication with the RF module and the power control device, wherein the field device controller is for controlling the power control device based on control data sent from the front end controller of the main power distribution and control unit via the wireless communication network to the wireless field device and received by the RF module.

2. The heat trace system of claim 1, wherein:

at least one of the wireless field devices further comprises a sensor that is in communication with the field device controller; and

the field device controller transmits sensed data from the sensor via the RF module and the wireless communication network to the front-end controller of the main power distribution and control unit.

3. The heat trace system of claim 2, wherein:

the sensor comprises a temperature sensor that senses temperature at a vessel of the piping system that is proximate to the associated heat trace cable for the wireless field device; and

the field device controller transmits sensed temperature data from the temperature sensor via the RF module and the wireless communication network to the front-end controller of the main power distribution and control unit.

4. The heat trace system of claim 3, wherein the temperature sensor comprises a RTD.

5. The heat trace system of claim 2, wherein the sensor is a sensor selected from the group consisting of a temperature sensor, a flowmeter, a vibration sensor, a pH sensor, a tank level sensor, and a valve position sensor.

6. The heat trace system of claim 1, wherein the power control device comprises a solid state relay.

7. The heat trace system of claim 1, wherein the wireless communication network comprises a wireless mesh network.

8. A wireless field device for use in a heat trace system, the wireless field device comprising:

a power control device having an input for connection to an electrical power source of a main power distribution and control unit of the heat trace system, and having an output for connection to an associated heat trace cable of the heat trace system, such that when the power control device is ON, the associated heat trace cable conducts current from the electrical power source of the main power distribution and control unit;

an RF module for communicating with the main power distribution and control unit via a wireless communication network; and

a field device controller in communication with the RF module and the power control device, wherein the field device controller is for controlling the power control device based on control data sent from the main power distribution and control unit via the wireless communication network to the wireless field device and received by the RF module.

9. The wireless field device of claim 8, further comprising a sensor that is in communication with the field device controller, wherein the field device controller is for transmitting sensed data from the sensor via the RF module and the wireless communication network to the main power distribution and control unit.

10. The heat trace system of claim 9, wherein:

the sensor comprises a temperature sensor that senses temperature at a vessel of the piping system that is proximate to the associated heat trace cable for the wireless field device; and

the field device controller transmits sensed temperature data from the temperature sensor via the RF module and the wireless communication network to the main power distribution and control unit.

11. The heat trace system of claim 9, wherein the sensor is a sensor selected from the group consisting of a temperature sensor, a flowmeter, a vibration sensor, a pH sensor, a tank level sensor, and a valve position sensor.

12. A method for energizing heat trace cables in a heat trace system that heat vessels in a piping system, the heat trace system comprising:

receiving, by a wireless field device of the heat trace system, via a wireless communication network from a main power distribution and control unit of the heat trace system, a control command to turn on a power control device at the heat trace system, wherein the power control device comprises an input connected to an electrical power source of the main power distribution and control unit, and having an output connected to an associated heat trace cable of the heat trace system; and

in response to receiving the control command, turning on, by a controller of the wireless field device, the power control device such that the associated heat trace cable conducts current from the electrical power source of the main power distribution and control unit.

13. The method of claim 12, further comprising:

sensing, by a sensor of the wireless field device, a condition of the heat trace system; and

wirelessly transmitting the sensed condition from the wireless field device to the main power distribution and control unit via the wireless communication network.

14. The method of claim 13, further comprising the main power distribution and control unit transmitting the control command to the wireless field device based on the sensed condition transmitted to the main power distribution and control unit from the wireless field device.

15. The method of claim 14, wherein the sensor comprises a temperature sensor and the sensed condition comprises a temperature at a vessel proximate to the associated heat trace cable.