Multiple orifice assembly

Claim 2

In combination, a conduit for conducting fluid flow, a multiple orifice assembly for increasing the flow resistance in the conduit comprising, two orifice plates spacedly supported in the conduit, one orifice plate being upstream in a fluid flow sense to the other orifice plate, each orifice plate having a single, centrally located opening therethrough; and a diffuser plate positioned intermediate the two orifice plates, said diffuser plate having a solid, impermeable, central portion, said diffuser plate further having at least two openings therethrough, said diffuser plate being spaced from the upstream orifice plate a distance less than that distance required for fluid issuing from said upstream orifice plate to fully expand back to the constraints of the conduit.

Claim 3

The combination set forth in claim 1, wherein said diffuser plate is spaced from said upstream orifice plate a distance equivalent to one diameter of said conduit.

Claim 4

The combination set forth in claim 2 wherein said other orifice plate is spaced one diameter of said conduit from said diffuser plate.

Claim 5

In a forced circulation steam generating unit having a plurality of steam generating tubes, a common header connected to said multplicity of steam generating tubes for delivering a supply of water to said tubes, a steam and water separating drum operatively connected to the discharge end of said multiplicity of steam generating tubes, and a pump connected to said steam and water separating drum and said common header for receiving water from said steam and water separating drum and delivering it to said common header, an improved multiple orifice assembly for the entrance of each of said multiplicity of steam generating tubes, each of said multiple orifice assemblies comprising two orifice plates spacedly supported in each of said steam generating tubes, each orifice plate having a single centrally located opening therethrough, one orifice plate being upsteam in a fluid flow sense to the other orifice plate, and a diffuser plate supported intermediate the orifice plates, said diffuser plate having a solid, impermeable, central portion, said diffuser plate further having at least two openings therethrough, said diffuser plate being spaced from the upstream orifice plate a distance less than that distance required for fluid issuing from said upstream orifice plate to fully expand back to the constraints of the tube.

Claim 6

In a forced circulation steam generating unit having a plurality of steam generating tubes, a common header connected to said multplicity of steam generating tubes for delivering a supply of water to said tubes, a steam and water separating drum operatively connected to the discharge end of said multiplicity of steam generating tubes, and a pump connected to said steam and water separating drum and said common header for receiving water from said steam and water separating drum and delivering it to said common header, an improved multiple orifice assembly for the entrance of each of said multiplicity of steam generating tubes, each of said multiple orifice assemblies comprising two orifice plates spacedly supported in each of said steam generating tubes, each orifice plate having a single centrally located opening therethrough, one orifice plate being upsteam in a fluid flow sense to the other orifice plate, and a diffuser plate supported intermediate the orifice plates, said diffuser plate having a solid, impermeable, central portion, said diffuser plate further having at least two openings therethrough, said diffuser plate being spaced from the upstream orifice plate a distance less than that distance required for fluid issuing from said upstream orifice plate to fully expand back to the constraints of the tube.