furnace sealing valves serve to create a gas-tight chamber.
upper and lower sealing valves are individually installed on the upper and lower part of the burden tank. and they are always switched on alternatively, which could well ensure the pressure stability of the furnace top.
meanwhile, both the upper and lower valves are driven by hydraulic cylinder, and are equipped with a signor source for position sensor. besides that, they are all sealed with fluororubber, which could be heated if needed.