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36 | TRAE Marine Review COOK'S METALLIC PACKING Probably no other appurtenance of a steam etigine is as much discussed among engineers as packing. In the past ten years it has become classified as metallic packing until now scarcely a large power plant is built without the engine con- tracts specifying some kind of metallic packing. "The sub- ject, therefore, reaches importance as the various features that go to make up a packing's working efficiency are con- sidered. What may be held among them as principal are: simplicity, or least possible number of parts; each part em- bodying a prominent factor to the whole; each part, while . subject in its service to the remaining parts, as little depend- ent upon the other parts as possible for its merit. . It seems that as this is the object to be sought in the device's mechanical make-up, the results it should work out are as follows: A minimum degree of friction on rods, a maximum lasting quality of the wearing parts, low cost .of renewal of wearing parts, convenience of application of packing and ease of making renewals, uniformity of design in varying kinds of service in order that conditions of all classes of packing may remain the same, and finally that the packing should in a high degree be automatic in its accom- modation to the working and wearing conditions of the en- gine. A prominent feature thereof is the ill alignment of rods,-so as to avoid the annoyance of adjustment. Cook's metallic packing, which we herewith describe, seems to ap- proach these qualifications without exception. ' The packing consists of spring guide "A,' which first en- ters stuffing-box of the engine, and holds spiral spring "B" in central position around rod. This spring presses against follower "C,' which in turn compresses segmental babbitt rings "F" and "J" to the rod. These rings receive their com- pression to the rod by means of their outside surfaces, which are conical. The rings fit into a cone shaped cup, or casing, "K" having the same degree of taper as the rings. Thus it is seen that as the spring assisted by the steam pressure, forces. the rings against the taper of the casing, the rings in turn' are compressed to the rod. The segments of the babbitt ring overlap each other, which seals the openings where segments are cut, and on one of the segments there ® "4 hag. ims lug is arranged so as to hold the openings of the segments at right angles to each other, making a leak through them impossible. The follower "C," which compresses the rings into the casing, is also tapered, to which a corresponding taper on the back of ring "F" is fitted. This results in a double cone packing. On the front end of the described casing "K," ball ring "N" is at- tdched with a ground joint, the opposite side of which is flat, and is ground to the gland "O." This arrangement is to allow the packing to follow any vibratory action of the rod, and still retain a steam-tight joint. The gland "O" to which the packing is fitted and which forms a part of the packing, is equipped with copper wire gasket "P," making a joint between gland 107 and cylinder head, when' gland is bolted home. ' Over ten years of experience has demonstrated that this packing will enter into any kind of steam service, from low pressure under high vacuum, to high pressure above 250 lbs., super-heated 150 degrees, without changing the design of a single part of the packing. This type of packing is extensively in use on both piston rods and Corliss valve stems of the Carnegie Steel Co., the New York subway, and for marine work, the double type packing, which comprises two distinct sets, exactly alike, bolted' together, and which is used in the United States navy, is especially recommended. The packing is made by the C. Lee Cook Mfg. Co., Louisville, Ky., and their new catalog, just out, which describes and illustrates fully all the features of the packing, will be gladly sent to any ad- ° dress upon request. PISTON VALVE FOR REVERSING STEAM TURBINES The accompanying illustration shows a piston valve re- 'cently invented by the Hon. C. Parsons for use in connec- tion with the application of steam turbines to marine pro- pulsion. In this work difficulty has sometimes occurred with the piston valve which regulated the steam supply to the turbines used for driving the vessels ahead or astern. The usual construction of the valve is either with an accurately machined mechanical fit or with split rings to prevent leakage. © Leakage is decidedly objectionable with a turbine as when going forward the leakage allows live steam to pass from .the "go ahead" turbine to the "go astern" turbine, thus causing considerable loss of power as well as destroying the vacuum in which the latter nominally runs. If the valve is made with such a nice fit as to pre- vent this leakage there.is danger of its jamming, and when . rings are used the friction of the rings under steam press- ure causes serious resistance to the operation of the valve. Mr. Parsons has designed the present valve to prevent this leakage, without using packing rings~or being under the necessity of accurately fitting the piston in the valve chamber. ! ross SS SSsao SS See Uf YM YY WY D Y MD LAE YZ S) XS \ = WN MARINE REVIEW Y The piston valves .as usually constructed consist of a cylindrical casing with two rows of ports near each end. Within this casing a cylindrical shell is introduced of such length that when it is pushed from one end to the other it alternately covers or uncovers' the ports. After live steam is admitted to the center of the shell, that steam will be permitted to pass into either one of the ports. and delivered to the turbines used for driving the vessels ahead or astern, according to the position of the shell. The improvement in the valve consists in providing a piston valve which has faces which are adapted to close against seatings fixed to the valvé casing when the 'valve is at its extreme position. Leakage is thus prevented when the valve is at either end of the chamber and the necessity of rings or accurate fitting of the piston is avoided. The 'illustration is a section through the valve, the valve being in its open or "go ahead" position. The. piston valve *