US1543963A - Metallic packing - Google Patents

Description

June 30, 1925. 1,543,963

J. N. WALTON METALLIC PACKING Filed July 25, 1925 packing, more or deterioration of Patented June 30, 1925.

UNITED STATES JULIAN N. WALTON, or NEW YORK, n. Y.,

ASSIGNOR TO CRANE PACKING COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

METALLIC PACKING Application filed July 25, 1923. Serial No. 653,673.

To all whom it may concern:

Be it known that I, JULIAN N. WALTON, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Metallic Packings, of which the following is a specification. v

My invention relates to improvements in particularly metallic packing used in condensers, evaporators and the like.

A flexible metallic packing has been developed which has been used very successfully in packing condenser tubes in that said packing not only prevents leakage, even where a high vacuum is being maintained, butalso substantially eliminates electrolysis the tubes. The packing is formed from soft'metal foil and has been made in long lengths, which are cut into shorter pieces of the required length so that they may be bent around to form a split ring. Such condenser packings are disclosed in Payne Patent 1,387,901, issued August 16, 1921.

It is the object of the invention to pro vlde an improved packing for this and similar purposes. A contributory object is to provide economically a flexible metallic packing formed as a continuous ring, i. e., with the gap eliminated. Other objects are to provide a packing of this character cOnsisting of rings which are accurately formed as to their dimensions so that they may be readily slipped over the condenser tubes and may be readily compressed longitudinally of the tube and caused to expand laterally thereof to provide a tight joint and good electrical contact.

Further objects and advantages will be apparent from the following description of several forms of the invention.

Figure l is a section through part of a condenser tube sheet showing the end of the tube and the stufiing box containing one form of my improved packing;

Fig. 2 is a similar section showing another form of packing;

. Fig. 3 is an enlarged view showing one of the packing rings cut open to illustrate the construction thereof;

Fig. 4 illustrates themethod of winding the ring;

Fig. 5 is a sectional elevation, on an en- 'tube, to provide a larged scale, of a modified form of inven- F ig. 6 is a similar section of a further modification;

Fig. 7 illustrates the an additional modified ring;

Fig. 8 is a section of a die illustrating the manner of forming the packing after any one of the rings has been rolled; and

Fig. 9 shows a typical section before'and after the application of lateral pressure.

Referring to Fig. 1, the end of the condenser or tube sheet, illustrated at l, consists ofa metal plate having an opening therethrough slightly larger than the condenser tube 2 which passes therethrough. Said opening is enlarged for the greater portion of its length forming a shoulder 3, the enlarged portion being screw-threaded throughout part of its length as shown at 4, whereby it may receive the screw-threaded ferrule 5. The packing ring is confined within the space thus formed and compressed between the inner end of the ferrule method of winding 5 and shoulder 3 to expand it laterally, i. e.

press transversely against causing it to the Wall of*the opening and against the joint sufliciently tight to prevent even minute bubbles from showing, at the same time permitting back and forth movement of the tube during expanform of packfing 51011 and contraction of the various parts of the condenser and at the same time maintaining sufliciently good electrical contact to substantially eliminate electrolysis which has been a serious difficulty in condensers of the oldertypes.

In forming the packing, a sheet or strip of sheet metal 7 is rolled spirally on itself, preferably on a mandrel, to form a ring of definite thickness. The sheet metal is preferably in the form of a narrow ribbon of a width somewhatgreater than the desired width ofthe final packing ring. Lead foil is suitable for this purpose although other soft metal ribbon may be used. Also the wide sheet metal may be rolled up and there after cut into rings of the desired width.

Each ring thus formed is then placed in a die 8, one form of which is illustrated in Fig.8, the ring slipping over a cylindrical projection and being confined within an outer ring 9. It is thereafter subjected to pressure from the tubular member 10 which is forced down on it or may be struck by hammer blows to compress the ring vertically, in the position in which it is shown, that is to say, in such a direction to make the ring narrower but somewhat thicker.

. During this operation, the substantially coners except that in actual practice the wavy portions are not quite as regular as those shown. The extreme outer and inner curved surfaces of the ring present the appearance -of a flat continuous strip of metal, which when examined closely, however, or deformed, discloses cracks where the metal has been folded. Throughout the major por-.

tion of the mass the interfitting sheets engage each other along diagonal lines whereby pressure on the sides of the ring develops radial components tending to thicken the ring, that is, the metal tends to press both inwardly and outwardly. The ring thus formed may he slipped into the opening surrounding the tube 2, installation being ac-. complished readily by means of a tool or mandrel, over which the ring is first slipped and from which it slides onto the tube, after which it may be swaged in place to press it in a direction to make it narrower, at the same time thickening it so that it bears firmly against the inner surface of the studing box and the outer cylindrical surface of the tube. Therings formed in this manner provide very effective packin in that they are soft and flexible and quite easily deformed by a calking tool or a packing tool. They may be very accurately .formed so as to fit the stufiing box very accurately and render the installation thereof comparatively easy.

Figure 9 illustrates in somewhat exaggerated manner the deformation of a packing of rectangular cross section when pressure is applied thereto in the direction indicated by the arrows. The increase in the vertical height of the section is substantially uniform throughout, particularly where the packing is confined in a stufling box. If an attempt is made to compress a cast ring the maximum pressure is available at the sides and diminishes toward the center of the packing. In other words, sufficient pressure is not transmitted to the central part of the packing to widen it as much as the sides. thereof. This results in a deformed structure which is not a rectangle but. which is widened more at the ends than in the middle. \Vith such a construction, an effective seal is not maintained and furthermore, the localized deformation of the packing crushes the comparatively soft metal condenser tubes.

In Fig. 2 a section of a stuffing box is shown with the packing ring, however, formed of two narrower rings 11, instead of a single wider ring. These rings are separated preferably by a fiber washer 12, a similar second ring being located preferably between the inner packing ring and the shoulder 3. These packing rings may be made of any suitable material, paper stock fiber being suitable, also certain asbestos products. The rings tend to swell under the influence of moisture and further insure against even a very minute leakage under extreme conditions of high vacuum, temperature and movement of the condenser tubes.

In Fig. 5, a modification is shown in which wiper r1ngs,'which may be similar to the fiber rings just described, are formed as part of the complete packing ring. The metal foil ring 13 is rolled around the fiber ring 14:-of which there may be more than oneand the composite packing thus formed is thereafter pressed in a die to cause the foil to surround the rings snugly on three sides, as shown.

In Fig. 6, a packing is made by rolling up a strip off-fabric 15 and a strip of metal foil '16 one being superimposed on the other. The fabric,'in the form shown, ma be of less width than the strip of metal a thou h this need not necessarily be the case. T e superimposed strips are wound spirally, forming a ring with a cross section somewhat as shown in Fig. 6, except that the metal, after being pressed inwardly in the die forms solid metallic ends. The inner surface of the ring is smooth and continuous with a fabric center strip imbedded in the metal.

In Fig. 7 the packing is formedby rolling a strip of metal 17 on a mandrel 18, in the form of a helix. The metal may be wound back and forth, if desired, to obtain the desired thickness or it may be wound from end to end in the same direction, with the joints preferably overlapping. After a tube of the desired thickness has been obtained, acking rings 19 may be cut therefrom and t ereafter pressed in a die to cause the metal to fold as in the forms previously described.

The advantage of the constructions described herein is that the packing rings are of such interior construction that they change their cross sectional outline readily under pressure when being ut in place, or when the packing ring or g and 5 is tightened. This results 111 applying uniform pressure to the condenser tube throughout raaaeee the packing area. Furthermore, there is no gap in the ring as a result of which there is less danger of deforming the tubes. Said tubes are made of soft metal, which necessitates the exercise of some care in calking the rings. WVith a continuous ring the pressure is uniformly applied to the tube throughout its entire circumference, as distinguished from a ring in which there is a slight gap which closes as the packing elongates, during the calking operation.-

\Vhat I claim is- 1. A metallic packing ring formed of coaxial substantially cylindrical layers of metal deformed to a substantiallycontinuous ring having smooth Walls and an internal plaited structure presenting interfittingfolds afiording easy further endwise compressibility in useand inward and outward radial expansibility.

Packing comprising a continuous ring consistlng of a narrow strip of soft metal rolled spirally on itself and compressed axially to fold the adjacent layers alternately back and forth and nest them Within each other.

3. Packing comprising a continuous ring consisting of a narrow strip of soft metal rolled spirally on itself and compressed axially to fold the superimposed layers back and forth, the inner and outer surfaces of said ring being fiat and smooth.

4. Metallic packing comprising a continuous flexible ring having four smooth sides, said ring in cross section comprising solid soft metal in the form of flexible strips of greater Width than the ring, folded to form smooth outer ring surfaces and bent back and forth in the manner of an accordion plaiting and fitting into each other Within the body of the packing.

In testimony whereof, I have subscribed my name.

JULIAN N. WALTON.

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