Re: Strange stuff from China

Trevor,
I'm pretty sure that "open" feedwater heating systems (where the steam and cold water directly mix) have to have two pumps. A centrifigual cold water pump moves the water from the tender to the heater; this was automatically controlled by a float valve. A positive-displacement hot water pump moves the hot water from the heater into the boiler; this was manually regulated by the fireman or engineer.
David Wardale (in his book "The Red Devil and Other Tales from the Age of Steam") reported that the Chinese units seemed very unreliable in service and somewhat undersized for the application (at least in the case of the QJ 2-10-2's).