Speeding up the Lpg Cylinder Filling Process with RFID

In 2002, EDiT iD Ltd, a New Zealand based radio frequency identification (RFID) reader development company, discussed with ELPIJI Sdn Bhd of Malaysia, an lpg equipment manufacturer, the advantages of deploying RFID tags on each of its cylinders.

EDiT iD commenced development of a low frequency RFID reader that would meet IECEx, an international standard for equipment operating in a potentially explosive environment in 2002. The goal of the RFID system was to speed up the process of filling lpg cylinders in an automated plant, and then to track each cylinder as it moved from filling plant to distributor to end user, and back to the filling plant.

“The process of distribution in many countries is torturous, with potentially many companies and individuals involved,” said Mark Powell, general manager of EDiT iD. “For example, in Malaysia, it’s normal that a distributor obtains cylinders from a filling plant then passes some of those cylinders to a sub distributor, who then passes them on to a delivery person for delivery to the end user.

“In the ideal scenario, when the cylinder is depleted of gas, the end user will hand the empty cylinder back to the person who delivered it originally, who will then return it to the sub distributor, who will at some stage return it to the main distributor, who will in turn return it to the filling plant. While this does occur most of the time, it doesn’t happen every time. As usual, the exceptions to the rule create the necessity to have sophisticated software solutions.”

EDiT iD’s first task was to provide RFID readers that could be safely used within the hazardous area of an lpg gas filling plant. Internationally, there are two standards for equipment operating in hazardous areas where gas is involved, ATEX and IECEx. It was mutually agreed that EDiT iD should develop its RFID equipment to meet the IECEx standard.

“Kosel Industries modified its lp gas filling plant software to enable the RFID system to be operated in filling plants where its equipment was installed and, by mid-2008, we delivered the world’s first IECEx approved RFID reader,” said Mark.

Every country has a requirement for cylinders to be tested by a competent company five or ten years after manufacture, and date of manufacture and tare weight are required before attempting to fill a cylinder. Currently, as empty cylinders arrive on the conveyor, an operator keys in the tare weight of each and visually verifies that it is within the requirements for testing and refurbishment, removing those that aren’t.

“Even with the operator solely concentrating on this verification process, each cylinder takes on average at least 30 seconds to verify that it should continue on the conveyor to be filled,” said Mark. “As the cylinders can’t pass this point until verified, there is often a further delay, especially if the operator is busy doing other tasks as well.”

The RFID system allocates and attaches a unique 125KHz tag to each cylinder, and its tare weight and date of manufacture are recorded on a database in a non-hazardous area.
“It takes less than a minute to place the non-removable tag and record the tare weight and date of manufacture of each cylinder,” said Mark.

The lpg cylinders are placed on the conveyor and stopped at the verification point, where the RFID tag is read and the date of manufacture and tare weight retrieved. If no tag is present or if the date of manufacture is not within requirements, the cylinder is automatically pushed to a side conveyor.

“Using RFID, the process of accepting or rejecting a cylinder is two seconds compared to a manual system where it takes at least thirty seconds and requires a human operator,” said Mark. “ELPIJI’s decision to invest in RFID and new filling plant software is clearly justified.”

 

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