Dear sir,
The point Tim Gardner makes is a good one. The theoretical design of the Venturi orifice trap means that it ought to show lower steam losses from idling equipment than an orifice-plate trap.
My understanding of the design is that there will be some leakage of live steam from idling equipment even with a Venturi configuration, depending on how well the equipment itself is insulated.
If Tim Gardner has any drawings and thermodynamic calculations for the Venturi system I would be pleased to include these in a future article.