Poor Electrical Heating Element Lives

Electrical engineering root cause analysis (RCA) related to electrical heating element failures and their solution to the problem.

Electrical engineering root cause analysis (RCA) related to electrical heating element failures and their solution to the problem.

Contents

Article Type:	Root Cause Analysis (RCA)
Category:	Electrical
Equipment Type:	Circuit Breakers
Author:	S. Raghava Chari

Note: This root cause analysis (RCA) is from real-time scenarios that happened in industries during the tenure of two or three decades ago. These articles will help you to improve your troubleshooting skills and knowledge.

Electrical Heating Element Problem

A flanged electrical heating elements assembly (HEA) bolted to the tank bottom nozzle heating the container Vacuum Residue (VR) keeps it at desired viscosity for easy pumping.

The HEA lasted few days only, not the expected years and years.

Root Cause Analysis

The author found charred remains sticking to the heating element sheath portions inside the nozzle and not beyond.

Pondering why he hit the answer in few minutes: the heating elements overheat the product stagnating in the nozzle; the carbonized product sticks to the sheath and prevents heat dissipation.

Eventually, the elements attain too high temperatures and give way. Hence, the heater assembly poor lives – the root cause.

Solution

Few minutes of thought yielded the answer to solve the problem; advice the element maker to start the heating wire 400 mm (300 mm Nozzle length + 100 mm safety length) away from the tip.

Connect the heating element to the terminal using copper wires (below-figure).

Vac Residue Tank Electrical Heating Element

This way the elements would heat the circulating product in the tank only and not the nozzle stagnating product, which will eventually attain tank content temperature by convection.