e g soft metal such as copper or a plastic material capable of withstanding the abrasive conditions such as those from the black liquor which may be available to act as a seal between the downstream edge 54 of the valve plate 42 and the opposite sidewall 52 or interior wall of the flash tank 10 a similar strip 60 may be along the upper and lower side edges of the valve plate 42 fig4 is a cross sectional schematic diagram of the inlet nozzle 34 taken along a vertical plane and showing a side of the flash tank 10 fig4 shows a view looking directly into the inlet nozzle 34 in a downstream direction of the flow passage 40 the rectangular cross sectional shape of the flow passage 40 is evident as is the oval or circular shape of the opening 56 to the flash tank 10 the valve plate 42 is shown extending partially across the flow passage 40 and forming a rectangular throat area t the valve plate also extends across and blocks a portion of the opening 56 to the flash tank 10 the area of the flow passage 40 and portion of the opening 56 blocked or closed off by the.