Patent ID: 7383859
Filing Date: 2008-06-10
Classification: F16K,Y10T

Abstract:
1. A main steam valve for a steam turbine, comprising: a main valve seat; a main valve body having an inner surface, defining a steam passageway, and an outer surface cooperating with the main valve seat; a bypass valve body axially slidably provided in the steam passageway of the main valve body so that a side surface of the bypass valve slidably engages with the inner surface of the main valve body, the side surface comprising a steam inlet that comprises a plurality of inlet openings arranged along the side surface, the inlet openings arranged in rows and columns, wherein the inlet openings in each row comprise holes from every other column; at least four keys provided in either the inner surface of the main valve or the side surface of the bypass valve; at least four keyways, each of which mates with one of the keys, provided in the other of the inner surface of the main valve or the side surface of the bypass valve, to prevent the bypass valve from rotary movement; and at least one groove provided on the side surface of the bypass valve extending axially, the at least one groove being other than one of the keyways, wherein each row of the inlet openings is arranged along a line aligned perpendicular to an axis of the bypass valve, wherein each of the plurality of inlet openings in each row is radially symmetrically arranged in the bypass valve and oriented such that each of the openings introduces steam toward the center of the steam passageway, and wherein positions of the openings in each of the rows are circumferentially offset from the positions of openings in the next inlet row.