Document qZEJNyjooEpzDpnpBq2VZMRj

How Can I Save Steam From Curing Cylinders? To CURB COHCflCTB BLOCKS W UW lit cylinder*, each 65 ft long and 6 fl in diameter. The block* are itseked in the cylinder*, which ore then filled with lire (team.. Tbo caring cycle contliti of eooking for 2 hr at 12 p*i, then gradually bringing pressure up lo 100 p*l and cooking lor 4 hr. Steam it then exhauited to atmosphere In ahottt 40 min. Only two cylinders ar* cook, ing at one time; the other* are being filled or emptied. Each operation tokea about iy$ br. Steam I* generated in an hrt boiler baring 2000 tq ft of heating surface. We draw raw water from tbe Oetrolt River lor feedwater. At times we do not use the feedwater pomp becou* we cannot keep steam up with cold woter going into the boiler. We tried using an injector but it woitee a lot of time. At present we re tiling *b#,, ton* ot 11,000 Btu cool in 24 br. ci\ It fired by an underfeed stoker, ja|J Can Towm readers suggest same $ of using the exhaust steam *o it be a total loss? I thought of uttnikyji beat feedwater but don't know beotjjl, make ate of it In the short ethaua pt/gjl of 40 min out of each 12 hr, Maybt ej|f engineer know* of * simitar tep tyj ha* a good method for using want II W, chief engineer. Readers' Answers Why Does One Cooling Tower Take More Air? IFe have two cooling lowers, each de signed to cool 1300 gpm of water from 105 to 85 F with a maximum wet bulb of 79 F. One u an induced-draft tower and the other a forced-draft. The induced-draft tower is IS ft wide, 32 ft long, and 25 ft high. It is equipped with three 7-ft disk fans oper ating at 325 rpm. Each fan, which has a 7Yt-hp motor, produces 46400 cfm of air at }&4n. of u>ater sidle pressure. The forced-draft tower is 20 ft wide, 36 ft tong and 26 ft high. It is equipped with two ll-/t aluminum-alloy adjustable blade fans operating at 250 rpm. Each of these fans requires 15 Ap and gives 120,000 c/m of air at Vs-in. pressure. Decking of both towers is the same. It consists of six sets of l%x6-in. raft ers with IxS-in. strips of wood, spaced 2ft, 3 in. apart and nailed on both sides of the rafters. IFater is sprayed on the decking by 1^-in. nossles at 5 psig. I would like lo know why the forceddraft tower requires about 72% more dr and 30% more horsepower than the induced-draft tower.--HB Calculate the Horsepower Output A r-o TOWER Requires more air bocause a certain amount o( air handled is recirculated. Fans create a auction along the aide of the tower, which 'tends to pull a certain amount ol healed air from the top or exhaust side ol the tower back to the inlet. Since this re circulated air does no cooling, or at best very little, it U necessary (or the 1-d tower to circulate more air. The I-d tower naturally takes tess power because the air is moving at a lower velocity. Another (actor, which contributes to the power consumption of the f-d tower, is that air after leaving the fan must make a 90-dcg turn, thus causing the fan to work against a higher head. Thia Is not true in the M fan where the air is taken in at a lower velocity. Here, air makes the turn into the tower decking at low velocity. Tbe fan discharge is directed In a straight line away from the tower. Motor sizes are probably rated val ues, not actual horsepower consumed. I suggest that HB determine power actually used by each fan. Power in put to each motor can be measured and the horsepower output calculated, using the Input value and the motor efficiency. This latter can be obtained from the motor manufacturer's dtta. P*d W Weiaenbacb, Wayne* Pa. Check Performance Of Both Towers Ficures civen In the problem are de sign ratings only. HB should check ' actual power consumed by each tower. Compare water- and air-outlet tempera tures, and relative humidities of outlet and inlet air for comparison. Two manufacturers, or even manufacturer at different times, mjj supply different towers lo meet tbe mxt operating conditions. The oetnjj standard design at the time will t*i offered, and standard fans used. A$ one manufacturer may provide a fntul er margin of safety as regards capacity*? either as a matter of policy or s uM guard due to lack of experience. AgiM higher power consumption with tvjj fans may be compenaated for by hlgkoL. first cost and more mainteosne* q|] three fans. Motor size* tnsy gin false idea of the power, at motors tifj only made in a limited number d] standard horsepower sizes. Thus, del three 7%-hp motors may be rurutia(| overloaded but not enough to juttifyl 10-hp motors; while the two 15-hpeotel may be consuming fast enough pe*) lo make the use of 10-hp motors lionable. \ An f-d cooling tower requires oenj power* not leaa, than a f-d. The dj Ivelocity from the former is high, sadlij wasted power. But this reduoes dtafofll of recirculation of air. (See "Perfor** once and Selection ot Mechanical Drt&, Cooling Towers,H by J Lichtenstein *Li Foster Wheeler Corp, in Transaction*^ ASME, October 1943.) An i-d f", possfng the same weight of dry *`r", a f-d ian has to handlo a greater weifbj: of vapor and also a greater volume J| air. Thia Is the result of moisture heat picked up by the air in pt*^ through the tower, and also h loss In the tower. W L Covan, 0***^ ford, Ont. (Continued on page 116) ere's an interesting exchanger using ex H tended surface for the more efficient cooling o( gases. Built by the Griscom-Russell Company of New York, the heal transfer sur face of this G-Fiu Gas Cooler is made of Anaconda Arsenical Admiralty Alloy tubes and fins. The use of this alloy provides rust proof, workable metal with special resistance to deeincificalion- . Arsenical Admiralty is but one of ten standard and several special Anaconda tube alloys for heal exchange applications. To help yon select , the alloys best suited for your needs, our Technical Department will be glad lo assist you and make recommendations. Also, write for your copy of Publication B2* which- provides detailed information! *** 114 (113) POWER February 1 fOWER . Fsbfusw 1948 The heot transfer element* of (hi* C-Ffn exchanger nsut of smnifej* lutes with longitudinal fins equally spaced about tA etrami/ercnce. Admiralty Alloy fins are thoroughly bonded to Arsenical Admiratty Alloy Tubes by o special mechanical process. This design gives six to eight times ej much outer o Inner surface --faeiiitatfng the transfer vj heat Jrom gas to cooling fluid. fA c/huzc<mc/a HEAT EXCHANGER TUBES THE AMERICAN BRASS COMPANY Cenersl Offices: Weterbury S8. Connecticut Subsidiary of Anaconda Copper Mining Company frM,.( Cn4i A*im Aossksh gu Ln, Mm* Om. fej*