Machine Improves Efficiency, Safety in Processing Dilute Agent
CCDC Chemical Biological Center Public Affairs | July 20th, 2017
These ampules show the difference between one that is sealed correctly and one that bubbled from the heat of the blowtorch during the sealing process.
The U.S. Army Edgewood Chemical Biological Center (ECBC) has acquired a new machine that improves speed, efficiency and safety in processing orders of dilute agent for customers.
ECBC’s Chemical Transfer Facility (CTF) manages chemical agents for research and testing, on behalf of the Army and the nation in accordance with the Chemical Weapons Convention treaty. The CTF, part of the Chemical Biological Applications and Risk Reduction (CBARR) business unit, prepares the dilute agent in support of the Chemical Agent Standard Analytical Reference Material (CASARM) Quality Assurance Team.
The CASARM Quality Assurance Team provides the National Institute of Standards and Technology (NIST) traceable chemical agent dilute solutions to customers, including laboratories and chemical storage depots. This year the CTF must prepare 2,400 vials to fill customer orders.
“The dilute agent solutions contain a high-purity sample of chemical agent dissolved in solvent that has been analyzed and certified, so other research labs, when they use it, know exactly what concentration they’re working with,” said Brandon Bruey, a chemist at the CTF. “Most customers utilize the dilute agent solutions as standards to ensure they can identify and quantify chemical agent material on analytical instrumentation.”
Once a dilute solution containing agents such as mustard, lewisite and sarin, among others, are certified they must be injected into open-ended glass vials called ampules, and the glass is heat-sealed closed. Until now, each ampule was carefully sealed by hand using a hand torch and glass rod. Although they can be sealed manually, the process can be quite labor-intensive. “To hand-seal that many is a time-consuming and labor-intensive process,” said Bruey.
But now the CTF has begun to utilize an innovative bench-scale ampule sealer that automatically seals each ampule. Ampules are loaded onto a slotted carousel and passed one by one in front of a fixed torch. The system spins each ampule and melts the glass over so that the glass is evenly sealed. “This gives every one of our vials a uniform seal and speeds up the process immensely,” Bruey said.
Previously, inconsistencies in the hand-torching method led to imperfections in the glass which could cause leakages. Technicians inspect each ampule inside a chemical fume hood before final packing; any defective ampule would automatically be snapped open and discarded, its contents transferred to another vial.
The new machine provides consistent heating with a gas mixture of oxygen and propane that is controlled to ensure the best flame temperature. The weld time can also be adjusted for optimum performance. If the vial is not in the flame long enough, it does not fully seal. If the vial is in the flame too long, the glass will expand like a bubble, forming very thin and fragile glass, Bruey explained.
“Once the flame temperature and weld times are set, the ampule sealer will produce a more uniform seal for all ampules,” he said. “It takes human error out of the equation.”
It takes a team of four, including chemists and chemical engineering technicians, to complete a production run: one filling the ampules, one operating the ampule sealer, one performing leak checks as each ampule comes off the sealer, and one person labeling the ampules.
“The machine didn’t eliminate the work,” Bruey said. “It just made it simpler and improved the quality of our product.”
About 10 different customers will receive dilute agent solutions this year, including other departments within ECBC. Other customers include chemical demilitarization operations such as the Pueblo Chemical Agent Pilot Plant (PCAPP) in Colorado, which uses it to verify their lab instruments are working properly and calibrated. “These are the gold standard agent solutions,” Bruey explained. “The labs work from them as a reference.”