Fusible plug

Chlorine is stored and transported as a Hquefied gas in cylinders of 45.4-kg or 68-kg capacity that are under pressure and equipped with fusible-plug rehef devices. Quantities in the range of 15 to 90 t are transported in tank cars having special angle valves on the manhole cover on top of the vessel. Tank barges of the open-hopper type having several cylindrical uninsulated pressure vessels are used for amounts ranging from 600 to 1200 t. Road tankers are used for capacities of 15 to 20 t. 

A further hazard exists when eompressed air jets are used to elean maehine eomponents in workplaees flying partieles have eaused injury and blindness. Cylinders may fail if over-pressurized or weakened by the applieation of heat. Liquefied gases, e.g. butane or propane, respond more rapidly to heat than the permanent gases sueh as nitrogen or oxygen. Cylinders are normally proteeted by pressure relief valves, fusible plugs or bursting dises. 

Cylinders are typieally proteeted from over-pressurization by frangible gold-plated dises and fusible plugs. 

More formal inspections also verily the operation of safety and other controls such as low water and fuel cutoffs, level controls, fusible plugs, pressure gauges, water glasses, gage cocks, stop valves, safety/relief valves, and BD valves and lines. Also, FW pumps, flue and damper arrangements, combustion safeguards, name plate specifications, set pressures, boiler connections, floats, mercury switches, bellows, and other components may be inspected. 

Is each receipt of material checked Yes. The supplier once sent a cylinder of phosgene. Since then, a test is performed by the maintenance staff. In addition, the fusible plugs are inspected for evidence of leakage, before a cylinder is hooked up. 

Are the operators following the operating procedures No. It is reported that some staff do not always check the cylinder s fusible plugs for leaks. Staff should be re-reminded of this procedural item and its importance. 

In some instances it may be beneficial to maintain process inventories of certain process vessels until the incident is actually threatening the container. The inventory of the vessel may be crucial to the restart of a facility or the contents may be highly valuable. Loss of the inventory may be criticized if frequent false trips of the ESD blowdown system occur. In these cases an automatic fusible plug blowdown valve could be installed which would only activate from the heat of a real fire incident. In this way, a false disposal of the inventory can be avoided. 

Deluge systems should generally be activated by automatic means. Activation by manual means defeats the objective of installing a deluge system, and fire water monitors should be provided instead as they are more cost effective where manual means is relied upon. Most systems provided at petroleum facilities are typically activated by a heat detection. Usually a fusible plug pneumatic loop detection system or UV/IR detectors are placed around the equipment. This insures activation when operators are not present and only when a real fire situation is present. 

What if there are pinholes or small leaks at the fusible plugs ... 

Fusible plug A safety relief device that will melt at a predetermined temperature. 

Each chlorine ton cylinder has three fusible plugs on each end of the tank to protect it from over-temperature. These plugs are designed to melt between 158° and 165° F (70° to 74° C). They are designed to protect the tank from overpressure if the cylinder is accidentally... 

The protection philosophy seems to be to protect the cylinder from overpressure by protecting it from over-temperature that would vaporize the liquid chlorine. Each of the fusible plugs is in a 3/4-inch threaded plug. If the fuse melts, the resulting hole is about 11/32 inch in diameter. 

For each of the following terms, write a sentence that shows your understanding of its meaning, atmospheres Boyle s law closed system Condensation Dalton s law of partial pressures fusible plugs ideal gas Kelvin scale... 

Parts of chlorine cylinder, tools and procedures to stop leaks, valve leaks, fusible plug thread and metal leaks, side wall leaks, and installationn of valve hoods. 

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