US3454086A - Steam dome - Google Patents

Description

Ju ly 8, 1969 5, PAUL ETAL I STEAM-DOME Filed Feb. 14, 1968 FIG. 3

INVENTORS BURTON PAUL ROBERT J. STOKER United States Patent 3,454,086 STEAM DOME Burton Paul, Princeton, and Robert J. Stoker, Phillipsburg, N.J., assignors to Ingersoll-Rand Company, New York, N.Y., a corporation of New Jersey Filed Feb. 14, 1968, Ser. No. 705,362 Int. Cl. F28f 9/00; F28b 9/10 U.S. Cl. 165-67 10 Claims ABSTRACT OF THE DISCLOSURE A steam dome for use with a steam condenser. The steam dome is formed by a first beam surrounding the inlet and a second beam surrounding the outlet. A truss arrangement interconnects and supports the first and second beams to form a space frame. The shell of the steam dome is formed by curved plates which are attached to the frame only at the inlet supporting beam and the outlet supporting beam.

Background of the invention This invention relates to steam domes for use with steam surface condensers and more particularly to an improved construction of such steam domes.

Prior to this invention steam domes included a shell structure which was supported by a plurality of internally mounted braces extending between the side walls of the steam dome and connected to the supporting structure of the condenser. Such bracing interferes with the flow of steam between the inlet of the steam dome and inlet of the condenser. One approach to eliminate such interference and the accompanying losses is provided in the application of Robert J. Stoker et al., Ser. No. 569,439, filed Aug. 1, 1966, now Patent No. 3,382,918, granted May 14, 1968. In the steam dome of that invention, the normal bracing of prior steam domes was replaced by first structural means surrounding the inlet, second structural means adjacent the outlet of the steam dome and a plurality of spaced apart ribs extending between the first and second structural means. The shell of the dome is welded to the ribs. These ribs transfer the load on the steam dome to the structural means at the inlet and the outlet. Although such arrangement leaves the inside of the steam dome substantially unobstructed and the internal ribs guide the flow of steam, the construction necessitates a large amount of welding during fabrication which results in high costs. It also requires the use of heavy plate material for the shell of the steam dome in order to withstand the load on the shell produced by external atmospheric pressure.

With such prior arrangements, when a lateral force is applied to the shell, due to the external atmospheric pressure, both in-plane and transverse forces are set up in the shell plate. In order to resist the force applied to the shell, heavy plate and bracing must be used. If a member which is to be loaded is curved in accordance with the amount of load to be applied to it, a smaller member can be used to withstand a similar load provided it is supported only at its edges. If the member is supported only at its edges, relatively small in-plane stresses will be set up in the member with transverse stresses greatly reduced provided that the reaction force in the member can be kept parallel to its surface. By this invention, it has been found that this principle can be applied to condenser steam domes to thereby permit their manufacture at a lower cost. Although curved plates have been used in condensers prior to this invention, as shown by US. Patent No. 2,111,240, issued to J. F. Grace, such prior apparatus does not take full advantage of the curved plate structure. In that patent, ribs in load transferring contact with the plates were employed. As soon as a supporting rib is in load transferring "ice contact with the shell plate, the shell acts as a beam and transverse forces are set up which cause a magnification of the otherwise small in-plane stresses.

Summary It is therefore the principal object of this invention to provide a novel steam dome for use with steam condensers which is of adequate strength yet reduces fabrication costs.

It is a further object of this invention to provide a steam dome which leaves the path between the inlet of the steam dome and the inlet of the condenser substantially unobstructed.

lt is still a further object of this invention to provide a steam dome which presents a better flow path between the inlet of the steam dome and the inlet of the condenser.

.In general, these and other objects are carried out by providing for use in combination with a condenser, a condenser dome having an inlet for receiving fluid to be condensed and an outlet for discharging the fluid into a condenser comprising: a frame including first structural means adjacent the inlet, second structural means adjacent the outlet and means for supporting said first and second structural means so that said first structural means is spaced from said second structural means; and shell means positioned within said frame closing the sides of the dome and secured to said frame solely at said first and second structural means.

Brief description of the drawing This invention will be described in connection with the following drawing wherein:

FIG. 1 is a perspective view of a steam dome employing one embodiment of the present invention;

FIG. 2 is a sectional view of a portion of this invention; and

FIG. 3 is a diagrammatic illustration showing the forces applied to the steam dome shell.

Description of the preferred embodiment In FIG. 1 there is shown a steam dome generally indicated at 1 having a plurality of sides defining an inlet 2 and an outlet 3 which leads to the inlet of a condenser, partially shown at 4. The steam dome of this invention is of simple construction. The dome includes a shell and a space frame. The frame includes first structural means 10, which is a box beam illustrated as an angle member, to which the shell is attached to form a closed triangle completely encircling the inlet of the steam dome. A second structural means 11 also illustrated as an angle member completely encircles the outlet of the steam dome. The shape of the beams 10 and 11 is not intended to be limiting but an open sided beam with the side plates closing the beam to form a box beam is preferable. Suitable supporting means such as a truss 12 made up of a plurality of beams 13 support the first and second structural means by extending between the first and second structural means. Although a truss arrangement has been shown, other structural arrangements may be used. The steam dome is supported by the supporting structure of the condenser 4.

The shell of the dome is indicated at 15 and includes plates 16 which extend between the first structural means 10 and the second structural means 11. The plates 16 are curved so that they are convex on the inside of the steam dome. The plates 16 are spaced from the beams 13 so that the sole means of support for the plates 16 are the beams 10 and 11. By being supported solely at the first structural means and the second structural means, stresses set up in the plates 16 will be primarily in-plane.

Referring to FIGURE 3, forces act on the shell 16 due to the vacuum within the steam dome produced by steam flowing through the steam dome. These forces are indicated by the arrows 20. By being supported solely at its ends, a resultant force which is parallel to the surface of the plate 16 is set up. The plates 16 are placed mainly in tension throughout their thickness, but this is a relatively low level tension compared to the compression and tension developed in the case where the side plates of the dome are supported at more closely spaced intervals along their surface. The resultant force is countered by an equal and opposite force at their points of support of the plate 16. Such points of support are the first structural member and the second structural member 11. The truss work 12 supports the first and second structural means but does not directly support the plates 16. The radius of curvature of the plates 16 may be different for each application and depends on factors such as the thickness of the plate and the amount of stress in the plate.

The corners of the steam dome and the portion of the plates 16 immediately adjacent the first and second structural means 10 and 11, respectively, will act as beams and will have a bending moment applied thereto. The corner pieces will be sufiiciently strong, however, because where the two side plates 1 6 meet, an angle brace is formed. The beam action in the area immediately adjacent the structural means 10 and 11 does not affect the strength of the dome.

In fabrication, if desired, the plates 16 can be attached to the box beams 10 and 11 in a straight form. As the condenser begins operation, the force developed by the vacuum produced in the steam dome will produce a curved plate 16. By using flat plates in fabrication rather than curved plates, further reduction of fabrication costs can be achieved.

Since there is no contact by the beams 13 and shell 15, a large amount of welding has been eliminated which reduces the overall cost of the condenser. An additional advantage gained by using the construction of this invention is that the thickness of the shell 15 can be substantially reduced. With prior construction plate thickness of one inch is common. With the present invention it is believed that plate thickness can be reduced to as low as one-eighth inch. A further advantage of the present design is the curved plates 16 provide a smooth unbroken path for the flow of steam between the inlet of the steam dome and the inlet of the condenser.

Although the steam dome of this invention has been shown with the shell plates 16 attached to the frame solely at the first and second structural means, there may be situations where other constructions are desirable. In some applications, a brace may be added near the ends of the shell plates of adjacent sides, or the plates 16 may be attached to the space frame at the junction of adjacent sides. With this construction, the portion of the shell between the junction of one side and its adjacent sides would be spaced from the frame while the junction or corner would be secured directly to the frame. The important feature is that the broad area of the shell be spaced from the frame to gain the structural advantages of this invention.

From the foregoing it is apparent that the objects of this invention have been carried out. It is intended that the foregoing description be merely that of a preferred embodiment and that the invention be limited solely by that which is within the scope of the appended claims.

We claim:

1. For use in combination with a condenser, a condenser dome having an inlet for fluid to be condensed and an outlet for discharging the fluid into a condenser comprising:

a frame including first structural means adjacent the inlet, second structural means adjacent the outlet and means for supporting said first and second structural means so that said first structural means is spaced from said second structural means; and

shell means positioned within said frame closing the sides of the dome and secured to said frame solely at said first and second structural means.

2. The combination of claim 1 wherein said shell means includes a curved plate spaced from said supporting means.

3. The combination of claim 2 wherein said supporting means includes a plurality of support members extending between said first and second structural means.

4. The combination of claim 1 wherein said first structural means encircles said inlet and said second structural means encircles said outlet.

5. The combination of claim 4 wherein each of said first and second structural means is a box beam.

6. The combination of claim 5 wherein said supporting means includes truss means extending between said first and second structural means.

7. The combination of claim 6 wherein said shell means includes at least one curved plate spaced from said truss means.

8. The combination of claim 7 wherein said curved plate is convex toward the inside of the dome.

9. For use in combination with a condenser, a condenser dome having a plurality of joined sides defining an inlet for fluid to be condensed and an outlet for discharging the fluid into a condenser, each of said sides comprising:

a frame including first structural means adjacent the inlet, second structural means adjacent the outlet and means for supporting said first and second structural means in spaced relationship to each other; and

shell means closing the side connected to said frame so that the portion of the shell which is between said first and second structural means and the junction of the side and its adjacent sides is spaced from said frame.

10. The combination of claim 9 wherein the shell means of one side is joined to the shell-means of the adjacent side and said shell means is connected to said frame solely at said first and second structural means.

References Cited UNITED STATES PATENTS 1,923,274 8/1933 Miller et al -159 2,111,240 3/1938 Grace 165161 X 2,273,225 2/1942 Semar 6095 2,453,662 11/1948 Graham 165114 3,139,926 7/1964 Tinker 165-111 3,382,918 5/1968 Stoker et al 1651l1 X ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS, Assistant Examiner.

US. Cl. X.R.

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