Any liquid or gas leak is a problem, but especially so if it's a corrosive, toxic or flammable fluid. Incorporating an excess flow valve, or EFV, into pipework improves safety by sealing off the flow should a pipe break or be disconnected.
EFV's are used in a wide range of equipment and piping systems, from natural gas distribution to refueling stations and now ChemTec can add HPLC systems to that list.
What is HPLC?
HPLC stands for High Performance Liquid Chromatography. Chromatography is a technique for separating and analyzing mixtures. A chemist might use it to find out what's in a water sample or a solution. There are several different methods. The liquid approach involves putting the sample in a solvent and pumping it through a column of chromatographic packing material. In simple terms, the distance each component of the sample moves up through the column indicates its composition.
The HPLC Application
ChemTec was approached by a company using Liquified Petroleum Gas (LPG) in an HPLC system. The LPG was stored under pressure and delivered to the HPLC system pump at up to 60 mL/minute. Their concern was that should the supply line rupture or become disconnected, LPG would be released. While such an event would be bad, it would happen in a lab setting, so the customer also wanted the ability to quickly reset the valve after correcting the fault.
Clearly, an EFV was needed. The complication was that 60 mL/minute is a lower flow rate than most such devices are designed for. Even allowing a margin to eliminate the possibility of false tripping meant the customer needed something to shut off a flow exceeding 120 mL/minute, still a low-flow situation.
The ChemTec Solution
ChemTec specializes in flow-flow fluid monitoring and control and has EFV's with both automatic and manual reset capabilities. For this application a manually resettable EFV125 was recommended. Manufactured from stainless steel, it resists corrosion and is suitable for air flows up to 155.70 SLPM (5.5 SCFM). (Note that a correction factor is needed for flows of other media.)
To learn more about EFV's contact a ChemTec product specialist today.