Industrial Process Temperature Sensor Comparison

Array of thermoucouple assemblies
Courtesy Durex

It's always useful to have quick references for things. Durex, a globally recognized manufacturer of electric heating solutions, published the Temperature Sensor Element Selection Guide included below in a recent blog posting. It provides a consolidated comparison of the four primary temperature sensing devices used for industrial process control. Many will find it useful, so we share it with you here.

All the technical expertise needed for your process heating challenges is readily accessible at BCE. Share your heating challenges with experts, combining your process and application knowledge with their expertise to develop effective solutions.

Industrial Temperature Sensor Comparison and Selection Guide from Belilove Company-Engineers

Basics of OEM and Industrial Electric Heating Elements - Part 2

This blog entry, reproduced from an electric heating element basics white-paper from Hotwatt, a leading US manufacturer of OEM and industrial heating elements. To download the PDF version, click this link.

Basic Heat Equations

Electric Heating Elements

It would appear at first that calculating all of the heat transfers and losses in a design would be a daunting task. Fortunately a number of equations were developed that help simplify this task. First the equations were divided into three tasks: the wattage needed to heat a material to a specific temperature in a given amount of time; the wattage needed to overcome the losses at operating temperature; and a special calculation needed to reach a melting or vaporizing point.

This equation calculates the amount of wattage (W) needed to raise the temperature of a material a specific amount in °F (ΔF) in a given number of hours (T), you first need to know the mass (m) of the material being heated and its specific heat value (c):

m × c ×ΔF

W=  -------------------

3.412 × T

The mass and specific heat of some materials may be found at www.hotwatt.com/table1.htm for metallic solids, www.hotwatt.com/table2.htm for solids other than metals, and www.hotwatt.com/table3.htm for certain liquids and gases.

Basics of OEM and Industrial Electric Heating Elements - Part 1

This blog entry, reproduced from an electric heating element basics white-paper from Hotwatt, a leading US manufacturer of OEM and industrial heating elements. To download the PDF version, click this link.

Electric heating elements
for OEM and Industry
(courtesy of Hotwatt)

The simplest definition of an electric heater is any device that changes electrical energy into heat energy. But from that simple explanation, electric heaters explode into a myriad of types, sizes, applications, and designs depending upon what’s being heated, the degree of heating needed, and the method by which the heat is applied.

The measure of electrical energy is called the Joule after its discoverer, James Prescott Joule. Through numerous experiments, Joule determined that the quantity

(Q) of heat transferred from electrical energy is proportional to the square of the current (I² ) multiplied by the resistance (R) for the period of time (t) through which it passes:

Q ∝ I² × R × t

However, one seldom sees a reference to Joules used in modern electric circuits. Instead, the controlling factor becomes that of power (P):

P = I² × R

You’ll note the only difference between the formula for determining power and that of determining Joules is the time component. The time factor in heating becomes readily apparent in any device that gets hot when an electric current flows through it: its temperature rises as time passes.