JPS62237008A - Blade ring for steam turbine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam turbine, and more particularly to a blade ring for a steam turbine having a baffle or baffle plate disposed around the outer periphery.

A vane ring supports a series of fixed vane diaphragms and is generally a semicircular cylindrical member with a bolted horizontal joint that fits within the turbine casing. In high pressure turbines, the blade ring has an integral baffle that is used to control the flow rate of cooling steam. However, since the radial thermal gradient exerts a lifting moment on the bolted part, which adds to the pressure and thermal stresses in the vane ring, bolting in the horizontal joint does not provide sufficient rambuca, resulting in , steam leakage occurs at the horizontal joint of the blade ring, reducing the thermal efficiency of the steam turbine. Although removing the baffle would eliminate the thermal lift problem, additional problems arise with respect to properly cooling the other components of the steam turbine.

11α11 In general, a steam turbine vane ring, when constructed according to the present invention, comprises upper and lower semicircular portions; bolting means for bolting to form a pressure-resistant horizontal joint between the upper and lower semicircular portions; and a bolting means disposed to extend circumferentially outwardly from each of the upper and lower semicircular portions. It has a semicircular arcuate plate. each of said arcuate plates having a plurality of slots extending radially inwardly from an outer circumferential edge thereof, thereby reducing thermal stress on said bolting means and improving pressure integrity of said horizontal joint; This prevents leakage of steam through the horizontal joint and prevents loss of thermal efficiency of the steam turbine.

Referring in detail to the 1 t day drawings, especially to Figure 1, it will be seen that the high pressure turbine (
0 The vane ring 1 is shown consisting of upper and lower semicircular parts 3 and 5, these upper and lower semicircular parts at the horizontal joint. They are bolted together by a plurality of bolts/nuts (only two shown) or other bolting means 7. Further, the vane ring 1 has a plurality of circumferential grooves 9 provided inside and a fixed vane diaphragm 11, and a sealing strip (not shown) is disposed in the circumferential groove 9. It is held by a caulking strip (not shown).

An integral circumferential baffle 13 extends radially outwardly from each semicircular portion 3 and 5 of the vane ring 1 . Baffle 13 has a plurality of radial slots 15 extending inwardly from the radially outer edge of baffle 13 beyond the center of the baffle. The radially inner end of the slot 15 terminates in a circular aperture 17 whose radius is greater than half the width of the slot 15 to relieve stress at the ends of the slot.

As shown in FIG. 2, the slots 15 are symmetrically spaced about a vertical plane, but the spacing between adjacent slots is equal, with each semi-circular section having approximately 36 mm as shown in FIG. °
There are four slots spaced apart at an angle of , and the recess 19 in the horizontal joint also forms a slot.

Although slotting the baffle as described above is simple and easy to implement, it solves the problem of reduced thermal efficiency of the turbine due to gaps in the horizontal joints and the resulting leakage of steam.

Additionally, the baffle's function of directing the flow of cooling steam is maintained to cool other components of the turbine.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a vane ring constructed in accordance with the present invention, and FIG. 2 is an explanatory diagram showing the angular relationship of the slots in the baffle. 1... Feather ring 3... Upper semicircular part 5
... Lower semicircular part 7 ... Bolt tightening means 13
... Arcuate plate (baffle) 15 ... Slot 19 ...
・Slot (recess)

Claims (1)

[Claims] A steam turbine blade ring having upper and lower semicircular sections bolted together to form a pressure-tight horizontal joint between the upper and lower semicircular sections. a semicircular arcuate plate disposed to extend circumferentially outwardly from each of said upper and lower semicircular portions, each of said arcuate plates extending outwardly from said upper and lower semicircular portions; Having a plurality of slots extending radially inwardly from the circumferential edge reduces thermal stress on the bolting means to improve the pressure integrity of the horizontal joint and prevents steam leakage through the horizontal joint. A vane ring for a steam turbine that prevents loss of thermal efficiency of the steam turbine.