Video: AE736A
AE736A: SF6 gas servicing cart built to order for large breakers and gas-insulated switchgear, which recovers down to below 0.5 mbar while compressing up to 50 bar. What it does, how its gas circuit works, and how it recovers, dries out, refills and cleans the gas.
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See the product page: AE736A: SF6 gas servicing cart
Video transcript
What the AE736A is, how it is built to order, and how it recovers, dries out, refills and cleans the SF6 of large equipment. In large breakers and gas-insulated switchgear, every millibar left in the compartment is gas that is lost. The equipment then has to be dried out under a deep vacuum before it is refilled, and the gas must go back clean. The AE736A does the whole servicing cycle in one machine. The figures. It recovers the gas down to below 0.5 millibar,
while compressing up to 50 bar, so it liquefies even in hot weather. Its vacuum circuit goes below 0.0001 millibar. It dries and filters the gas to 0.5 microns, and recovers 99.9% of it. Four functions, in one cart. It removes the gas and stores it as liquid. It evacuates the equipment to dry it out. It re-evaporates the gas and refills the equipment. And it purifies the gas, absorbing decomposition products and moisture. The circuit. From the equipment, the inlet regulator and the suction gauge.
An oil-free suction pump, in parallel, for the deep end of the recovery. The compressor, the condenser, the discharge gauge and the high-pressure shutdown. The drier, the purifier and the filter, the moisture indicator, and the storage tank. Below, the refilling line, and the vacuum line on its own. Recovery. The gas leaves the equipment through the regulated inlet, which also takes high-pressure bottles directly, without throttling. The compressor raises it to up to 50 bar and the condenser liquefies it.
It is dried, purified and filtered on its way into the storage tank. For the last part of the recovery, an oil-free suction pump draws the gas from the equipment and feeds it to the compressor. That is how the residual pressure goes below 0.5 millibar, and why so little gas is left in the compartment. Then the equipment is evacuated for dry-out. The vacuum pump works on its own line and takes the compartment below 0.0001 millibar, so air and moisture are out before the gas goes back in.
Refilling. The liquid gas from the tank is re-evaporated and returned to the evacuated equipment. When a weigh scale is fitted under the tank, it shows how much gas has gone in. In outline, a service follows that order: connect, recover, evacuate and dry, refill, and purify whenever the gas needs it. With the optional touch screen, start and stop take a single touch. Each cart is built to order. Trailer, caster or skid mounting. An aluminium enclosure or roll-up tarpaulin sides.
With or without storage on board. Oil-less, oil-free or oil-lubricated compressors, any voltage and frequency, and manual or PLC control, with an optional touch screen. Safety is designed in. The compressor shuts off automatically at the maximum allowable pressure, and a warning light shows a high-pressure stop. An internal equalisation circuit allows the restart. Valves and fittings are instrumentation grade,
and heavy-duty gauges and a colour-change moisture indicator follow the process. And the specification, in one table. Where it is used: gas-insulated switchgear and breakers, bus ducts, accelerators and transformers that use SF6 as dielectric, during commissioning and maintenance. It works with tanks, bottles or other carts, and it is sized for breakers of the 256 and 400 kilovolt class. SF6 gas handling, from Amperis.