Leak is a four-letter word that no industrial manufacturer ever wants to hear. Industrial leaks can slow down manufacturing lines, destroy equipment, and possibly harm workers — making them a top concern for industrial teams.
For that reason, leak detection systems are a critical yet often unseen aspect of the manufacturing process. Today’s manufacturing plants rely on specialized equipment to detect the smallest leaks, but in some cases, an easy way to detect a leak — or prevent one — is with the human eye peering through sight glass.
Sight glass, thanks to advanced engineering, can stand up to the most adverse conditions in the manufacturing world in order to keep equipment running smoothly and protect workers from hazardous chemicals.
Through the looking glass
Sight glass is designed to withstand adverse conditions in industrial plants, including high pressures, excessive corrosion, and extreme temperatures. Two aspects of a modern sight glass, the quality of its parts and the seal, ensure its effectiveness in extreme environments.
The glass alone is a specialized piece of equipment. Because the glass comes in direct contact with the contents of a pipe or container, it must be made strong enough to resist damage, decay, and outright failure. Many modern sight glasses are equipped with borosilicate glass, a specialty glass that can withstand high temperatures, thermal shock, and chemical corrosion. This chemically unique glass is rugged enough to resist abrasion and scratches, thermal changes, fluctuating temperatures, and chemical attacks, but still offers clear views into pipes, storage tanks, and extraction systems when installed as part of a sight glass.
But toughness isn’t enough. Borosilicate glass must be exceptionally smooth and flat in order to create a flush seal when it’s fabricated into a sight-glass application. Even small imperfections in the glass can prevent a proper seal and allow a leak that can have catastrophic effects. All of the qualities of borosilicate glass, along with strict tolerances during assembly, minimize the risk of failure.
Leak detection with the human eye
Installed on various equipment, including manufacturing vats, hoppers, and reactors, sight glasses allow workers to see inside massive pieces of equipment from a safe vantage point. In pipelines, sight glass helps workers monitor the flow of liquid, and also check the color, clarity, and viscosity of the material.
“While leak detection systems use electronic sensors to monitor for pressures or volumes that fall outside normal tolerances, looking through sight glass can be an additional form of leak detection in certain applications,” said Andy Obertanec, Product Sales Specialist at Jacoby-Tarbox, a Clark- Reliance Product. “By monitoring flows through pipes, for example, operators can ensure substances continue to flow and pipes remain airtight. Sight glasses allow workers to observe changing liquid levels in a pipe that can indicate or confirm a leak has occurred.”
For example, sight glass installed on the outlet side of a valve designed to stop and seal flow allows workers to visually check if a proper seal is maintained. Another scenario involves lube systems: If machines that are designed to continuously lubricate bearings are struck with a leak, machinery can lock up and then shut down industrial production, so observation through sight glass is crucial in ensuring proper functionality.
The same principle holds true in scenarios where chemical spills can halt production, as is the case in oil refinement. When draining oil tankers, workers on the ground must verify each car is fully drained—oil refiners don’t want to move rail cars that aren’t completely drained because any small spill can cause an EPA spill zone quarantine and halt production. Sight glass, therefore, helps ensure proper and full rail car drainage, and continuous monitoring of the flow prevents accidental leakage or backups.
How sight glasses offer another layer of detection
Sight glasses play an important role in the safety and monitoring of manufacturing equipment. The strict standards and specialized glass in each device reduce the risk of failure in the most inhospitable manufacturing applications, and help guarantee the safety of workers on the production line.
The borosilicate glass in these devices is manufactured to stay strong against fluctuating temperatures, corrosive substances, and intense pressures. These qualities of sight glass allow workers to peer into a vat or pipeline, while minimizing risk of leakage, an important, but sometimes overlooked, cog in the manufacturing process.
Tina Gallo, Manager is Applications and Logistic Services for SCHOTT’s Home Tech division.