1840.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



121 



TOPHAM'S PATENT SLIDE-VALVE COCKS. 



Fig.l. 



Fib- ■^■ 



DESCRIPTION. 



The outer case, in wliicli tlie slide-valve is enclosed 

 and worked, consists uf a box, a a, with socket outlets, 

 ti I), cast in one, and a cap, c c, secnreil to tlie box by 

 means of four wrouglit-iron bolts, tlie position shown 

 at dcldd, in figures 1, 2,3, and A. Fig. 1 represents 

 a vertical section of one form of the patent cocks, and 

 fig. il is a plan of it with the cap oW; ef is the slide 

 with a rack cast upon the back of it;yy is a cast-iron 

 spindle, with a screw cast upon it : g g l^ the stuffing- 

 box; h li is the gland. 'I'liis cock is intended onlj' for 

 what are termed siiiglt-i.>.ceA cocks. 



Fig. 3 is a vertical section of another form of the 

 patent cocks, and tig. 4 is a plan of it with the cap oti'; 

 I i is the slide witli the double face, and with lugs, 

 kk, cast upon it, to receive a female brass screw-nut, 

 / /, antl a w ronght-iron square-threaded screw spindle, 

 m m, as in the common double-faced screw cocks. 



Observations. — In the screw cocks commonly used, the box is cast 

 in two pieces, and the outlets are generally made with flanges, to 

 which a socket and spigot piece with corresponding flanges are bolted. 

 It is a well known fact that cast iron is not so liable to corrode as 

 wrought iron, and therefore that dispensing with numerous bolts and 

 three lead joints, will not only render the casing more durable, but 

 enable it to be made at less cost. The side joints in the box or casing 

 sometimes yield unequally ; this prevents the slide shutting close to 

 the face, thereby allowing the cock to "let by :" this is prevented by 

 dispensing with the joint. Some cocks of the smaller sizes have here- 

 tofore been cast with spigot and socket instead of flange outlets ; in 

 the patent cocks, sockets are cast on both ends of all sizes; although 

 it might originally have been supposed that by removing the cock, ami 

 leaving the flange, spigot and socket attached to the main or service, 

 a new cock might have been introduced without breaking the main or 

 service ; in practice, when a new cock has to be introduced, the main 

 or service is broken, and the junction formed by a double socket : it is 

 therefore evident that the separate spigot and socket castings with 

 flange joints are imnecessary. In the single-faced cock, the reason for 

 introducing a cast iron screw and rack instead of a wi'ought iron screw, 

 is that cast iron is less liable to corrosion than wrought iron, and there- 

 fore more durable. 



The advantages of the patent cock are its simplicity and greater 

 durability, (owing to there being fewer joints,) and cheapness. The 

 facings of the cocks hereinbefore described are iron ; if, from the na- 

 ture of the water, cast iron is liable to corrode rapidly, the socket or 

 sockets for single or double-faced cocks are made to screw in, and can 

 therefore be faced with brass. The water supplied by the Water 

 Works Companies in London, is of such a quality that corrosion of cast 

 iron is very slow, and the extra exjiense of brass faces, or gun-metal 

 screws, would be greater, when the interest of the money expended is 

 taken into account, than the renewal of the cocks when rendered use- 

 less by corrosion. 



Mr. Wicksteed, the engineer, has introduced these patent cocks into 

 the services of the East London Water Works, and in a certificate 

 dated Nov. 23, 1S3S, he states, that 



"The chief difiereiice between your patent cocks .iiul those commonly 

 used, consists in the body of the cock being cast in one, and the outlets in 

 cocks of all sizes being cast on the body, instead of li.aviiig flange, spigot and 

 socket pipes attached thereto. By this means you undoubtedly not only dis- 

 pense with the greatest portion of the lead-joints and screw bolts ordinarily 

 required, and in consequence reduce the cost also, but the slide will be less 

 Mable to get out of its true working position, which it is apt to do from un- 

 equal yielding of the side-joints ; and thus the necessity and expense of re- 

 l)airs, which have been rendered hitherto necessary, will I)e dispensed with. 

 Although the application of the cast iron worm and rack may not be new, it 

 is certainly not in general use : and, in single-faced cocks, may be used to 

 great advantage. It will, in my opinion, Ije more diualile, and is more sim- 

 ple, and less expensive, than the wrouyht iron screw spindle and brass screw 

 nut. 



" My experience inclines me to consider the use of brass facing in cocks, 

 where Thames or River Lee water is used, unnecessary, as I know several 

 cast iron sluice gates, with iron facings, that have been worked, and exposed 

 to the action of these waters, for a period of nearly thirty years, that are now 

 in as good a state as possible ; the faces are not at all corroded, and the gates 

 are water-tight. I therefore consider the use of brass, in such instances, as 

 unnecessary and expensive. Nevertheless, should the water contain salts 

 that wouhl aftect cast iron so as to injure the faces, the mode you propose in 

 your specification, for facing with brass, appears to me well calculated for the 

 purpose, without affecting the principle of dispensing with the side and other 

 joints and bolts." 



Mr. Wicksteed has furnished Mr. Topham with another testimonial 

 of recent date, March lb, wherein he states, that 



" After having used your patent cocks constantly for two years, I feel en- 

 abled to speak as liighly of them as I did in my letter to you dated Nov. 23, 

 1838, and would stJ'ongly recommend their general adoption," 



