Thermocouples and Digital Control Panels

Electrical Immersion Heaters  

In process heating the manufacturing processes and many industrial applications use immersion heaters for a variety of purposes like heating solvents, oil, water, salts, liquefied wax and for preventing fluids from freezing in chilly weather. These immersion heaters can be easily installed in large reservoirs and tanks used to store fluids for use in industrial processes.   The heating element is immersed above the substance to be heated, which provides fast and efficient heat transfer for even heat distribution and rapid heating. These immersion heaters are low cost heating solutions with an electrical power source, which provides a clean and non-hazardous operating environment. Immersion heaters are largely used in industries like petrochemical, oil & gas, food processing and automotive industry.  

Digital Control Panels   Immersion heaters come in various designs and installation types to cater to the various industrial environments heating requirements. Immersion heaters come equipped with a digital control panel or box that contain the control valves for maintaining temperature and overall functionality of the heating device.   The box can be mounted on the outside wall of the tank or container while the heating element can be immersed inside the tank. The digital control box regulates the desired temperature for the substances in the tank and helps improve the overall performance of the Immersion heater. The control box ensures even heat distribution inside the reservoir and helps to prevent overheating of fluids and any degradation of fluid quality.   Manufacturers of Industrial heating appliances provide customized digital control panels to suit your industrial heating requirement. Installation types and terminal boxes of the digital control panel can be customized depending on the kind of heating device you plan to use and the mounting area of the Immersion heater.  

Types of Control Boxes and their Uses   The digital control panel consists of a terminal box, which is made of special material that helps prevent dust accumulation and is waterproof, explosion resistant and moisture proof.   There are two types of Digital Control Panels offered by manufacturers of Industrial heating appliances.  

NEMA 1: The NEMA 1 is a special digital control panel with a terminal box specifically designed for use in heating fluids in conventional and safe industrial environments. Such digital control panels are used to regulate performance and functionality of heaters in standard industrial applications.  

NEMA 4: These types of terminal boxes are built using advanced sturdy technology and are typically used in high-end industrial applications requiring outdoor operations. The terminal box is made of material that helps in creating resistance to moisture and other environmental hazards like humidity and rain.  

Digital Control Panel Design and Specifications   Industrial heaters are installed along with digital control panels. Typical installations include mounting of the control box on the container wall. Additional accessories include sensors like thermocouple, RTD, wires, switches and power connections for electric power. The wiring and connections provide power source to the electric heater while the thermocouple helps to regulate the desired temperature and observe heater performance.   Most heaters with wattage specifications ranging from 30 to 200 amperes have standard digital control panels for temperature control. These control panels can be customized according to your heaters wattage density and requirement. Customizations can be made to support heaters with watt density up to 600 volts and mounting types can be modified to include remote based automated control boxes. Typical customer support features of the digital control panel installation include:                Power switching unit for electric power feed Design specification documents to help you get familiar with functionality and installation details Spare parts for replacement Operating user manuals for digital control panels    

Applications   The applications of digital control panels depend on the industrial requirements and there are multiple installation types to support different applications.  

Basic digital control box is used within heaters having standard elements like thermocouple sensor, limit controlling system, timers and related components.

Advance digital control box is an ideal solution for heating devices that are used in standard and high-end industrial environments. These control panels provide support for various electrical installations.

Contactor stages are control panels that are used with multi-stage heaters used for heating different kinds of fluids like water, oils, salts, chemical solvents and gases.

Base Load SCR is an installation type that is used in multi stage heating to provide stage control.          

Fig2: Digital Control Panel Installation  

Benefits of Digital Control Panels   Installing a digital control panel with an industrial heating device comes with many benefits and provides a lot of advantage for the heating process. Some of the benefits include:

  • Control panels provide a cost effective and efficient mechanism for temperature regulation and heating device performance measurement.
  • Installation type for control panels include remote controlled execution that makes it easy to operate.
  • There are alarms and timers included that help identify any functional errors and deviations in temperature.

Thermocouples and Their Uses   Thermocouples are sensors that are included with heating appliances to regulate temperature and monitor any changes in heat. They ensure even heat distribution for fluids in industrial containers and to prevent overheating of fluids. The thermocouple consists of two different metallic elements in the form of wires entwined at one end. This thermocouple junction senses temperature changes through the voltage produced by it, which corresponds to the temperature change. Most Immersion heaters come equipped with thermocouples that help in maintaining constant temperature and even heat flow.   The control box usually contains the thermocouple and it is typically installed at the outside of the container wall to provide protection from the fluids inside. The operating mechanisms for the heater are usually installed in a ‘closed system’ or separate room that helps protect the heater from environmental hazards and malfunctioning.   The digital control panels can be customized by the industrial heating appliances manufacturers to support your environment requirements and heater specifications like watt density, size, shape and placement area. Digital control panels are a cost effective and efficient solution for improving overall functionality of the heating device and for providing desired temperature for liquids in Industrial processes.