US2594659A

US2594659A - Valve construction

Info

Publication number: US2594659A
Application number: US6907A
Authority: US
Inventors: Ivar L Langvand
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1948-02-07
Filing date: 1948-02-07
Publication date: 1952-04-29
Anticipated expiration: 1969-04-29

Description

Aprl'29, 1952 l. l.. LANGVAND VALVE CONSTRUCTION Filed Feb. 7, 1948 \NVENTOR l ATTORNEY ffm [angl/and Patented Apr. 29, 1952 UNITED STATES PATENT OFFICE 2,594,659- l VALVE CoNs'rniie'frid'ri IvarI L. Langvand, Barberton; Ghio; assigner to The Babcock & Wilco' GompayfNew Yorks- N. Y'., a corporation of New Jersey Application February 7, 19428',K Serial No. 5,4907

(ci. mir-' ret 8 Claims.

This invention involves an improvement in a valve construction, and more' particularly in a valve particularly adapted for use as an attempei'ator control valve, automatically operable in response to'te'rriperatre changes of a high temperature' fluid, to variably proportion the nuid flow between two flow paths one of which bypasses an atte'riiperator while the other includes the attemperator. Such a valve is particularly adapted in a system for controlling the superheat in a high pressure steam generator-superheater installation.

In casting a metal body for a high pressure valve adapted for use with superheated Ysteam of a pressure of the order of 1200 p. s. i. and above, the external walls must be of substantial thickness while the diaphragm, because of the limited diier'e'nce in pressures on its opposite sides may be" `made relatively thin to advantageously attain a compact structure.

It is an object of the present invention to provide a valve construction for such purposes havingV a thick wall valve body with an integral diaphragm which is so arranged that any stresses which may occur during changing temperature conditions involved in the casting of the Valve body and diaphragm, or which may occur under" high pressure and temperature operating conditions Amaybe controlled and limited in their nal effect on' the diaphragm, in such a manner that the operation of the valve will not be functionally impaired.

More specifically it is the object of the invention topro'vide an integral diaphragm extending between opposite thick walls of a valve body whichis so arranged the strains, resulting from the cooling of the molten cast metal of the diaphragm or as the' result of operating temperature conditions, will occur within the diaphragm. To this end, the transverse diaphragm which is cast integrally with the opposite body walls is arranged with a central elongated wall section of materially less thickness than the remainder of the diaphragm to provide a zone for localization of such strains. Such a strain may be evidenced by a crack, but because of its symmetrical location with respect to the contiguous opposite' walls and because of its limited character will not involve an opening of sufficient flow area 'to impair the functioning of the diaphragm as a means for separating the flow passages.

The invention will be described with reference to the accompanying drawing in which a pre-Y ferred embodiment is shown, and other objects 2. of` the invention willY appear as` the description proceeds.

In'thev drawings: Y I

Fig. l is a longitudinal section through thel illustrative valve;

Fig. 2v is a longitudinalV section `at right angles toFig. l, taken on the line 2-2 of Fig.v 1, and looking in thedirection of the'v arrows applied to thatpsection line;

Fig. 3is transverse' section onf the linefj-f--S oi Fig. 1, and loking in the direction of the arrows; .and l Fig. fi is a"frag'rnentaryV section on the line t-iioi Fig. 2, illustrating the diaphragm construction inthe z'oneof itsl weakened sectionA e'ii tending along a median line aligned with the axis of the valve damper.

The illustrative valve includeswa valve body It?. This is asingle piece casting forming' anV inlet l2, the main outlet lliy and a side outlet I6. Formed as* an integral part'of the casting anddividing the flow paths leading to the sepa-rate outlets-is a transverse diaphragm i8, the up`` stream edge of which is disposed closelyr adjacent to the circumferential edge of the circularcentral web 20 of a two-bladed damperl 22. This damperis a single piece casting with the valve blades 2"'4- and ze, on opposite sides of the web zo, set 9o`fapart as-clearly indicated inthe drawings (Fig. 2)'. The web 20 forms a substantialV continuation of the flow dividing wall formed by the diaphragm IB, and, due to the 90" setting of the valve blades, the yflow to theoutlet i4 is decreased and the flow to the outlet I6 simultaneously and correspondingly*increased when the damper is turned in one direction.

Due to the fact that the diaphragm I8 is integral with the valve body casting, and also due to the' wide temperature differentials to which the valve parts' are subjected when thevalve is used as apart of a system for controlling the superheat of high temperature steam, thermally created stresses of considerable magnitude may develop in the diaphragm. They are apt to result in such crackingl of the diaphragm that the effectiveness f the valve might be impaired. This is prevented and the position of cracking controlled by constructing' the integral diaphragm of relatively small wall thickness and of spherical sirf'a'ce with alinear (or circumferential) section of reduced thickness, as indicated at 30 in thc drawings. This" section extends intermediately of the diaphragm, from a point midway of the curved free edge of the diaphragm adjacent the web 20 to a point midway of the opposite side of the diaphragm where it joins the thicker metal of the valve body adjacent the side outlet I6. With this construction, if the diaphragm is caused to crack by thermally created stresses, the crack will occur along the line of the reduced section 30, and the sections on either side of the crack will not be subject to unequal stress conditions because of the location of the crack in its central position.

The diaphragm I8 is of a spherical form having its upper circular free edge I9 in alignment With the circular valve web 20, while the other margins are integrated with the body walls. The spherical form contributes to its strength as a diaphragm and avoids straight line strut or tie action between the spaced side walls of the valve body. As shown by Figs. 1 and 4 the diaphragm has a circumferential section 30 of reduced thickness extending from the free edge I9 to the lower edge 2| where the diaphragm joins the body at the bottom of the outlet portion I6. In the illustrative valve Where the connections I2, I4 and I6 are of 71A internal diameter and the body wall thickness of the order of 2 inches, the diaphragm is of spherical form having a radius of 14 inches, and of a Wall thickness of 5/8 inch tapering down to a minimum Wall thickness of 1A inch as shown by Fig. 4. The wall thickness reduction is accomplished by grooves from both faces of the diaphragm so that the remaining wall thickness is symmetrically positioned between the contiguous main portions of the diaphragm. A small hole 23of a diameter 0f the order of the minimum wall thickness extends through the diaphragm at its lower margin for the purpose of preventing the extension of any strain effect beyond the margin of the diaphragm and into the body wall.

With the above described arrangement, the spherical shaped diaphragm is so supported from the surrounding body that even should a crack develop along the predetermined line of the reduced thickness no appreciable relative displacement of the edges marginal to the crack will occur and substantial leakage through the diaphragm will be avoided.

The valve damper 22 is rotatably mounted at its right-hand side (Fig. l) within a bonnet 32 removably secured over a side opening in the valve body by the bonnet studs 34 and their associated stud spoolsy 36 and hex-nuts 38.

The bonnet 32 has a finned extension 40 Within which is rotatably mounted a valve stem 42, with the interposed thrust bushing 44, thrust collar 46, packing 48, stuiing box gland 50 tightenable by a stud I, and outer bushing 52. The outer end of the valve stem is squared as at 54 for the reception of a valve operating member, and provided with a washer 56 and a top bolt 58 for holding an operating memberlon the valve stem. The opposite end 60 of the valve stem, on the opposite side of the thrust collar 62, is similarly squared and operatively joined by the sleeve 64 with the similarly squared stud B6 integral with the damper 22. A pin 68 secures the sleeve 64 to this stud. To the left of sleeve 64 the damper is formed with a bearing stud 'I0 rotatable within the top damper bushing '12.

The rotatable mounting at the opposite side of the damper includes the bearing stud 14, the lower damper bushing 16, and the end plug 18 secured to the valve body I0 by the end plug studs 80.

What is claimed is:

l. In a valve, a one piece metallic valve body presenting separate valve outlets and a transverse diaphragm separating ow paths extending from the valve interior to said outlets, said diaphragm having a line section of reduced wall thickness at an intermediate position relative to the diaphragm width, the wall thickness of said line section of the diaphragm being much less than the wall thickness of the remainder of the diaphragm to present a thermal stress localizing line across the diaphragm.

2. In a valve construction, an integral metallic valve body presenting two separate valve outlets, and means mounted in said body for movement to control fluid flow through said outlets, said body having a diaphragm separation fluid flow paths from said means to said outlets and having a free edge adjacent said means and extending across the valve body at a position remote from said outlets, said diaphragm also having a line section of reduced wall thickness extending across the diaphragm to an intermediate position along the free edge of the diaphragm, the wall thickness of said line section of the diaphragm being much less than the wall thickness of the remainder of the diaphragm to present a thermal stress localizing line across the diaphragm.

3. In a valve for variably proportioning fluid flow through a plurality of valve outlets, an integral metallic casting presenting said outlets and an inlet, and means turnably mounted and extending across the interior of the valve body for regulating the ilow of iluid to said outlets, said valve body casting having an integral diaphragm extending across the interior of the valve body and dividing iiow paths leading from said means to said outlets, the diaphragm having a free edge adjacent said means and extending across the casting at a position remote from said outlets, said diaphragm being grooved to present a narrow stress localizing zone along a median line section of a wall thickness substantially less than the thickness of the remainder of the diaphragm, said section extending from. a position along the inner surface of said body and ybetween said outlets to an intermediate position along the free edge of the diaphragm and adjacent said means.

4. In a branched valve construction, a single piece metallic tubular valve body presenting a main fluid flow path and a branch communicating therewith, a diaphragm integral with said body and disposed transversely of the valve body and providing a continuation of the branch into the valve body, and flow control means mounted within the valve body and extending transversely of the branch and the main fluid flow path, said means including oppositely effective valve damper elements at different radial positions and operable across the branch and the main fluid flow path on opposite sides of the diaphragm, one of said valve members closing the branch while the other valve member is opening the main fluid flow paths, said diaphragm being grooved to present a narrow zone of localization of thermal stresses along a line section extending in the general direction of fluid ow from an intermediate position adjacent the flow control means to a position intermediate the outlets for said branch and the main flow path, the wall thickness of said line section of the diaphragm being much less than the wall thickness of the remainder of the diaphragm to present a thermal stress localizing line across the diaphragm.

5. In a valve, a one piece metallic valve body presenting separate valve outlets and a transverse diaphragm separating iioW paths extending from the valve interior to said outlets, said diaphragm having a line section of reduced wall thickness at an intermediate position relative to the diaphragm width and extending generally in the direction of iiuid flow, the wall thickness of said line section of the diaphragm being much less than the Iwall thickness of the remainder of the diaphragm to present a thermal-stress localizing line `across the diaphragm. y ,Y

6. In a valve'constructioh, an integral metallic valve body presenting two separate valve outlets, and means mounted in said body for movement to control iiuid'flow through said outlets, said body having a`diaphragrn separating fluid flow paths from said :means to said outlets and having a free edge'adjacent said means and extending across the valve body at a position remote from said outlets,"said diaphragm having' a line section of reduced wall thickness extending transversely ofthe free edge of the diaphragm to an intermediate position along the free* edge of the diaphragm, the wall thickness of said'line section of the'diaphragm being much less than the wall thickness of the remainder of the diaphragm to present a thermal stress localizing line across the diaphragm.

7. A unitary metallic valve body presenting a single uid inlet and a plurality of fluid outlets, and means movably mounted within the body for controllably dividing the fluid flow from said inlet into a plurality of paths leading to vthe outlets, said body having a transverse diaphragm separating saidA paths extending from saidmeans to the outlets, the diaphragm being groovedVK along a line extending from a position adjacent said means and intermediate the width of the diaphragm to a position adjacent said outlets and also intermediate the diaphragm width to present a narrow zone of localization of thermal stresses.

8. A one piece metallic valve body presenting a single fluid inlet and a plurality of fluid outlets, and means movably mounted within the body for controllably dividing the fluid flow from said inlet into a plurality of paths leading to the outlets, said body having an integral transverse diaphragm separating said paths extending from said means to the outlets, the diaphragm being grooved Aon both sides along a line extending from a positionv adjacent said means and intermediate the width of the diaphragm to a position adjacent saidio'utlets and also intermediate the diaphragm width to present a narrow zone for the localizatio'r'if'of thermal stresses.

IVAR L. LANGVAN D.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS France Sept. 18, 1925