Document 446nYDJYjRqRoGr1NmBovagje

licit can cause heat and destruction. Strangely enough, in /Afj case slippage would be leas on a 244a. bell subject to same pull. Reason is that a belt weigh* ing .less per linear loot creates leas centrifugal force. Hence a larger per* centage of the belt Is available lor driv* ing, as less Is needed to overcome cen trifugal force. Brantford, Ont. W L Goyan Resurface Flywheel Years aco I saw a rider belt on a drive similar to that mentioned by IM. It was in a plant of tho JohnrMaaville Co in Brooklyn. The rider bell did slop ihe slip. Bui belt dressing was also applied, and I believe it was partly re* sponsible for the result Another method is to apply a friction facing on the flywheel. This friction material can be nothing more than thin duck canvas, glued securely on the sur* face of the pulley. Usually it is the smaller pulley that slips, not the large one. In this case the idler pulley very likely takes core of the smaller pulley, giving it sufficient arc of contact. This suggests the use of another idler pulley as shown' above. This will increase the arc of contact on the flywheel. I have never seen two idlers on a single drive but see no reason why they would not be prac* ticable. I believe the friction loss would be less than with a rider faelL My suggestion is this: First use a high-grade belt dressing. If that doesn't solve the problem completely, give the flywheel a friction surface. I believe that would cost less than a second idler pulley. Cost, these days, is important. Newark, N.J. J H Squires (log, **) - 1 * X fs log, HO f/p 5*000 s velocity of belt in ft Der min T, Maximum tension of bdt coefficient of friction, which is 0.3 for leather to cast iron arc of contact in radians. For convenience, log, can be changed to 2.3026 X logi. The arc of contact is obtained from the formula shown oo the sketch above, and is found to be 215 deg. Since we do not know the diameter of the idler, which would add some to ihe arc of contact, we will omit it. T, is obtained by r, - t x a - r, T - aitoweble unit tension of I sq in. of leather belt; it Is 42.1 lb per sq in., and A is the area 7*. centrifugal tension of belt, ob tained by r Hr X * *P W -- weight of a ft length of belt, de tained by multiplying 0.43 by the croaa-sectional area of the belt 1 assume 3-ply belt is X in. (hick. m belt velocity In ft per sec squored. 9 - the force of gravity 32.2. 1 worked this out, and found the belt good for over 408 hp. Since it is equal to the job, let us see where the trouble Is. Tho only thing we can alter is the friction between flywheel and belt. The practical way is to clean the contact side of the belt thoroughly. Re move all oil and gum with a good cleaner or fuller's earth. After this ( thorough cleaning, ooat the aurfaca* freely with neat'a-foot oil. Tho proeess| should be repeated regularly. I believe j this will stop all slipping. I cannot see how a rider belt wiQ 1 help. Bronx, N. Y. 1 Cloaca Gatrru I Put Idler at Flywheel IM COULD PROBABLY ELIMINATE tOtBS slip on flywheel by using a rider belt. Usually the slip between belts offsets any gain because of excessive wear o both belts. His idler pulley should be placed at A or B, as in sketch below, depending on rotation of flywheel to increase bell wrap or contact on flywheel. To get best results don't have belt too tight before applying the idler. Neither should belt he too slack, as this will put an exces sive load on the Idler. This is especially important an heavy multiple leather belts like /Afi as they are hard to flex. I recommend using a small amount of good-quality-stick belt dressing to in crease belt grip on flywheel. If outside of belt is rubbed with a little neat's-foot oil every few months it keeps belt pll* (Continued on page 152) Belt Is Heavy Enough To Pull the Load I CHECKto 1M'$ PROBLEM to see if his belt is good for the horsepower it must deliver. I used the following formula: m |4?| POWER January 1444 ...increasing resistance to dezincification ifteen years ago engineers of The Ameri Fcan Brass Company found that the addition of a very small percentage of arsenic to the standard Admiralty Alloy would substantially increase its resistance to corrosion by dczincification. Arsenical Admiralty "439" alloy has been produced since 1934, and has given consistently satisfactory performance in almost every kind of service. This alloy is but one of 10 standard and several special Anaconda Condenser Tube Alloys. They cover a wide range of heat transfer requirements. For further information, ask for Publication B*2 -- or consult our Technical De partment on choosing the alloy best fitted to your needs. Illustration shows Anaconda Arsenical Ad miralty Tubes going into a new condenser being built for a Missouri utility by the C. H. Wheeler Manufacturing Co. in Philadelphia. This dual bank, two-pass type condenser, has a surface area of 11,000 sq. ft. and a capacity of 77,000 pounds of steam per hour. Tubes are 34" O.D. x .049" wall and 16' 2-34" long. Tubes sheets are Anaconda Muntz Metal -- H4" thick x 104" diameter. t '* cmutcanaa CONDENSER TUBES THE AMERICAN BRASS COMPANY General Offices: MPoterbury 88, Connecticut Subsidiary of Anaconda Copper Mhung Company l Canada: AjvacONOa Akieican Diass Ltd. Nnt> Threat*, Ont. POW|R Janu#fy |94B II)