Abstract
A moisture separator for a steam turbine power plant for separating moisture from a flow of vapor or gas that includes a bundle of vanes having a corrugated portion and a trailing edge. The trailing edge includes means to collect moisture on the surfaces of the trailing edge. These means can include a clip-like attachment, or a U-shape of the trailing edge itself. The collection means on the trailing edge contribute to the overall moisture separation efficiency of the moisture separator and a decrease of risk of damage to the steam turbine driven by the steam flow.
Claims
1. A moisture separation apparatus for a steam turbine power plant for the generation of electricity, the moisture separation apparatus comprising: a housing with an inlet for a gas or vapor or steam flow, a bundle of vanes arranged within the housing, where the vanes are vertically arranged in parallel and evenly spaced from one another, and each vane comprises a corrugated portion arranged closest to the inlet for the gas or vapor or steam flow and a trailing edge portion arranged opposite from the inlet, and a clip attachment on at least one vane of the bundle of vanes enveloping an end face of the trailing edge portion and extending over a first surface of the trailing edge portion and a second surface of the trailing edge portion, wherein the clip attachment comprises two legs converging and extending at an angle to the first surface of the trailing edge portion and to the second surface of the trailing edge portion, and wherein the two legs of the clip attachment have chamfered end portions.
2. The moisture separation apparatus according to claim 1, wherein the clip attachment is arranged over the end face of the trailing edge portion and extends over a length of the trailing end portion.
3. The moisture separation apparatus according to claim 1, wherein the clip attachment comprises a first leg, a second leg, and a bend portion, attached to the end face of the trailing edge portion.
4. The moisture separation apparatus according to claim 3, wherein the clip attachment is attached to the end face of the trailing edge portion by means of spot welds.
5. The moisture separation apparatus according to claim 3, wherein the first leg extends over the first surface of the trailing edge portion and the second leg extends over the second surface of the trailing edge portion.
6. The moisture separation apparatus according to claim 1, wherein the clip attachment is configured for collecting moisture on the first surface of the trailing edge portion and for directing the moisture to a bottom end of the at least one vane.
Description
BRIEF DESCRIPTION OF THE FIGURES
(1) FIG. 1a shows a perspective view of a bundle of corrugated vanes as may be arranged in a moisture separator according to the invention.
(2) FIG. 1b shows a cross-section of the corrugated vane of FIG. 1a along the line Ib-Ib.
(3) FIG. 2a shows an individual corrugated vane of an embodiment of the moisture separator according to the invention and in particular a trailing edge having clip-like means to collect moisture.
(4) FIG. 2b shows a cross-section of the corrugated vane of FIG. 2a along the lines IIb-IIb.
(5) FIG. 3a shows an individual corrugated vane of an embodiment of the moisture separator according to the invention and in particular a trailing edge having a further embodiment of clip-like means arranged in the mid-region of the trailing edge to direct moisture to the bottom of the vane.
(6) FIG. 3b shows a cross-section of the corrugated vane of FIG. 3a along the lines IIIb-IIIb.
(7) FIG. 4a shows an individual corrugated vane of an embodiment of the moisture separator according to the invention and in particular a trailing edge having a U-bend means to collect moisture.
(8) FIG. 4b shows a cross-section of the corrugated vane of FIG. 4a along the lines IVb-IVb.
(9) FIG. 5a shows an individual corrugated vane of a further embodiment of the moisture separator according to the invention having grooves imparted on the trailing edge's surface.
(10) FIG. 5b shows a cross-section of the corrugated vane of FIG. 5a along the lines Vb-Vb.
(11) FIG. 6 shows a cross-section of an individual corrugated vane of a further embodiment of the moisture separator according to the invention having a protrusion on the trailing edge's end face.
DETAILED DESCRIPTION
(12) A moisture separation apparatus according to the invention is shown in figure la as it may be used for the separation of moisture from a vapor flow 1, for example a steam flow for a steam turbine of a power plant, where the steam flow is directed via an inlet in an apparatus housing onto a bundle 2 of vanes 3. The vanes 3 are corrugated on a large part of its area, the corrugations having maxima 3a and minima 3b. The steam flow 1 passes through the narrow spacing 3d between the vanes 3, which are a fraction of the period of the corrugation's period. The spacing between the vanes is assured by spacer elements 10 as shown for example in FIG. 2a. The vapor flow passing between the vanes follows an undulating path due to the corrugation and exits the panel and the apparatus at the end of the vanes 3 via trailing edges 4 shaped substantially planar. While moisture droplets in the vapor flow are impeded by the corrugations as the flow passes over them and collect there by flowing down to the bottom of the vanes, a significant amount of moisture remains still in the vapor flow at the end of the vane and collects on its trailing edge 4. For the purposes of definition and identification within this document, the trailing edge 4 may be described as shown in the cross-sectional view in FIG. 1b having two sides, a first side 4a, a second side 4b, and an end face 4c, and furthermore the corrugations having maxima 3a and minima 3b extending parallel to the length l of the trailing edge 4.
(13) FIG. 2a shows a front view of one of the vanes 3 of the bundle as shown in FIG. 1. The steam flow 1 is indicated to pass over the corrugations 3a, 3b of the vane from the left and leave the vane over the trailing edge 4. The figure shows a first embodiment of the means to collect moisture on the surface of the trailing edge, where these first means are a clip-like attachment 5 enveloping the end face of the trailing edge and extending toward the corrugations of the vane. The cross-sectional view in FIG. 2b shows the specific inventive shape of the clip 5 arranged over the end face 4c of the trailing edge 4 and extending over the entire length l of the vane's trailing edge. The clip 5 having a first leg 5a, a bend portion 5b, and a second leg 5c, is attached to the end face 4c of the trailing edge for example by means of spot welds. Its first leg 5a extends over the first side 4a where the second leg extends over the second side 4b of the trailing edge. Both legs 5a and 5c extend at a slight angle to the surfaces of the trailing edge.
(14) The clip as shown allows moisture having collected on the first side 4a and flowing down from a corrugation maximum to be received by the clip's end and flow into the space between the clip and the trailing edge surfaces. Similarly, moisture having collected on the second side 4b and flowing along toward a corrugation minimum will be collected by the leg 5c extending to the point, where the moisture may otherwise be re-entrained by the steam flow. In the example shown, the second leg 5c extends to the point where the corrugation begins, whereas the first leg 5a extends only over part of the planar first side of the trailing edge leaving part of it free. The clip's legs can however also be of equal length. A suitable choice of the length of the clip's legs depending on the shape and type of the corrugation can optimize the effective direction of a moisture film into the space between trailing edge surface and the clip 5, from where the moisture can run down to the bottom of the vane. Rounded or chamfered end portions of the clip's legs can further optimize the effective direction of moisture into the clip.
(15) FIGS. 3a and 3b show a variant of the clip of FIGS. 2a and 2b, where clip 6 attached to the trailing edge 4 extends over a portion of the trailing edge 4, for example at approximately the mid-point of the length of the trailing edge. The device 6 has for example a triangular shape having one side extending vertically. In its cross-sectional view the clip has symmetrically shaped legs 6a and 6b extending parallel to the trailing edge's first and second sides.
(16) FIGS. 4a and 4b show a further embodiment of the invention, where the trailing edge itself is shaped to generate the means of to collect the moisture. The trailing edge is bent in a substantially U-shaped form, having first arm 7a, a U-turn bend 7b, and a second arm 7c. The first arm 7a of the U-shape is directed at a small angle away from the mid-axis 3′ of the corrugation of the vane 3. The second arm 7c of the U-shape extending substantially parallel to the mid-axis 3′. The second arm 7c extends as far as the onset of the corrugation at point 3e.
(17) A further embodiment of the invention as shown in FIGS. 5a and 5b comprises as a means of collecting the moisture on the trailing edge one or more grooves 8 on one or both trailing edge surfaces. Moisture droplets adhere to the groove and are directed to the bottom of the vane.
(18) FIG. 6 shows a further embodiment of the invention, where the final end face 4c of the trailing edge comprises a protrusion 9 extending away from the trailing edge surface and having a portion 9a that extends towards the corrugation 3a, 3b in the manner of a barb. The protrusion can have for example the shape of an arrow or any barb-like device. Moisture can collect in the space enveloped by the trailing edge surfaces and the barb and be directed to the bottom of the vane.
