US2143477A - Liner for condenser tubes - Google Patents

Description

Jam 0, R. E. DILLO N ET AL 2,143,477

I LINER FOR CONDENSER TUBES Filed June 24, 1937 zz a 1 ff I g W A Jfl Z/ 2/ 7 170%)? if Wz'Z/azz waifl /aa may Patented Jan. 10, 1939 UNITED STATES PATENT OFFICE LINER FOR CONDENSER TUBES Application June 24, 1937, Serial No. 150,144

2 Claims.

This invention relates to improvements in heat interchangers of the tubular type, and more particularly to condensers wherein a liquid, such as Water, is caused to flow into and through a number of pipes which open into a header.

When a liquid flows from a reservoir such as a condenser header into a tube, it undergoes an abrupt change in velocity and consequently an abrupt change in pressure, so that just within the orifice of the tube the stream may contract away from the wall of the tube and then expand again to fill the tube. The pressure drop at the contracted point in the stream tends to cause dissolved gases to separate from the stream and to collect in the space between the stream and the tube wall. The presence of such gases promotes corrosion of the tube wall adjacent thereto and, to a lesser degree, along the interior of the tube where the gas bubbles are dragged along by the stream. To combat such corrosion or erosion, short liners have been used in the inlet ends of the tubes. These liners greatly prolong the lives of the tubes but corrosion or erosion occurs at the inner end of the liner, although at a considerably slower rate than at the entrance of an unlined tube.

It is an object of the present invention to reduce the rate of local corrosion of the tube wall at the inner end of the liner. According to the invention, this is done by providing within the liner one or more longitudinal fins or the like adapted to prevent a swirling or helical flow of the liquid through the liner. For reasons not wholly understood at the present time, such structure actually results in a marked reduction in the rate of corrosive action in the tube wall just beyond the inner end of the liner. In places where the practice is to employ successive liners of increased length to cover corrosion occurring during the use of shorter liners, the effect of the invention is to increase very substantially the period of use of a liner before it is replaced by a longer liner.

For a more complete understanding of the invention, reference may be had to the following description of certain embodiments thereof, and to the drawing of which Figure 1 is a sectional view of a portion of a condenser having a liner therein embodying the invention.

Figure 2 is a similar sectional view showing a modified form of the invention.

Figure 3 is a section on the line 3-3 of Figure 1.

Figure 4 is a section on the line 4-4 of Figure 2.

Figure 1 illustrates a fragmentary portion of the header In of a condenser through which the inlet end of a condenser tube l2 projects. There are various means for securing the end of the tube in the header, one such means being illustrated in Figure 1 and consisting of a ferrule M which is screw-threaded into the header and which abuts against suitable packing 16. This ferrule surrounds the inlet end of the tube l2 and secures it in position. Inserted in the inlet end of the tube and ferrule is a liner or sleeve 20, the inlet end of the liner being preferably flared as at 22 to conform in some measure to the stream lines of flow of the stream entering the tube. The inner end of the liner is preferably internally chamfered as at 24 so that the liner ends in a sharp edge 26, thus avoiding any shoulder behind which an eddy can form. In spite of the use of the tubular liners, it has been found that the condenser tube tends to corrode the tube adjacent to the inner end of the liner, as at 2B. In some power plants where condensers are used, it has been the custom to replace the liners periodically by longer liners so as to cover up and protect the successive corroded areas 28 before such corrosion reaches a serious stage. It is an object of the present invention to improve the liner in such a manner as to retard materially the corrosion of the condenser tube adjacent to the inner end of the liner, and thus to increase the intervals between replacements of the liners. To this end, one or more suitable longitudinal guiding fins are provided within the liner extending in the same direction as the axis of the liner. This guiding means prevents swirling flow of the stream and acts in combination with the chamfered inner end of the liner to retard the corrosive action of the stream on the tube.

The means for guiding the flow may be in a variety of forms, two of which are illustrated on the drawing by way of example. In Figures 1 and 3 is shown a single fin or partition 30 which extends diametrically across the tube and from the inlet end thereof a substantial distance toward the inner end thereof.

Figures 2 and 4 illustrate another form of the invention consisting of a plurality of fins 32 projecting from the wall of the liner toward the axis thereof and extending from the inlet end thereof a substantial distance toward the inner end. Four such fins are illustrated in Figure 4, but it is understood that a greater or smaller number of such fins may be employed if desired.

It is evident that various other modifications and changes may be made in the invention as herein shown and described without departing from the spirit or scope of the invention as defined 5 in the following claims.

We claim:

1. In a condenser tube for the flow of water therethrough, a liner within the inlet end portion of said tube having its inner end internally cham- 10 fered to a sharp end edge, and a plane fin within the liner extending a substantial portion of the length thereof in the same direction as the axis thereof.

2. In a condenser tube for the flow of water therethrough, a liner within the inlet end portion of said tube having its inner end internally chamfered to a sharp end edge, and a plurality of plane fins projecting from its inner wall toward the axis thereof and extending longitudinally for a substantial portion of the length thereof.

ROBERT E. DILLON. ALBERT E. MACE.

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