Show application of electric drive contributed the application of electric drive in the operation of a cement mill and the advantages to be derived are unusually well exemplified in the plant of the southwestern portland cement company at vic torville california the town of victorville Vic torville is in the southwestern part of california about about one hundred miles from los angeles on the santa fe railroad the tracks of which pass by the plant affording a convenient outlet for the finished product the mill has an output of barrels a year of portland cement and employs ap irk X ta sixty cycle 72 hp rpm volt motor driving klinker elevator proximately eighty people all of the build buil ings are of substantial concrete construction built to withstand the severe conditions imposed by the heavy cement mill machinery installed the system of manufacture used is known as the wet process and water for use throughout the mill is raised to a reservoir on a hill back of the plant by a 15 horse power motor driven triplex pump rock and shale are brought to the mill from the quarry which is located seven miles distant by steam locomotive hauling trains of cars which have two compartments or hoppers one of which is dumped at a time to the crusher electric current is purchased from the southern sierras power company thus re lieving the company of the expense and trouble incident to the operation of a power plant current is received at volts and stepped down to volts for application to the various motors installed throughout the mill the transformers and switching apparatus are of the outdoor type located immediately adjacent to the mill the current is taken from here to a seven panel marble switchboard built by the westinghouse electric manufacturing company from which it is distributed to the various power and lighting circuits in the mil the lime rock is delivered from the hopper cars direct to the crusher but a reserve pile of crushed stone amounting to between and tons is maintained sufficient to keep the mill operating for a period of approximately thirty days this reserve is maintained in the event of an accident such the railroad service as a washout crippling from the quarry to the mill the crusher and williams mill are driven by a horsepower westinghouse type CW wound rotor motor as shown in figure 1 which break the rock into pieces about the size of a walnut or a little larger from here the rock is elevated to a storage bin by a bucket elevator driven by a 30 horsepower motor and thence by belt conveyor to the pulverizing house up to this time no water has been put with the rock except what is thrown on at the time it goes into the crusher which is done with a hose to eliminate whatever dust rises at that time during the process of pulverization water is added eliminating the dust after being thoroughly pulverized the mixture is taken to the slurry tanks where it is kept in motion by air agitation until ready for admission to the kiln there are six slurry tanks served in pairs by elevators operating at a speed of approximately eighty eight feet per minute for elevating the mixture from the pulverizing house tanks and driven by a 7 horse power constant speed motor after the mixture has been thoroughly agitated it is transferred to the slurry tanks nearest the kiln from here it flows into a raised and lowered by a 14 horsepower 1725 rpm motor by means of remote control from the klinker end of the kiln the large laige scale is visible to the operator at the klinker end and lie he can feed the proper amount of mixture to the kiln and watch his fire at the same time the rotary kiln the rotary kiln is approximately feet long and twenty feet in diameter lined with fire brick and heated by an oil burner to a 4 4 74 W sixty cycle hp rpm volt westinghouse type CW motor g 44 P L 7 sixty cycle 50 hp 3 phase rpm motor driving rotary kiln sump and is delivered to the kiln by a motor operated measuring device illustrated in figure 4 which shows the rear of the scale the dipper is made in the shape of an S the outlet being in the center by raising and lowering the dipper in the sump the amount of slurry entering the kiln can be controlled the dipper is driven by an extended shaft provided with two universal joints from one of the elevators and is temperature of about 2500 degrees which is measured by a radiation pyrometer it is driven at a speed of one revolution per minute by a 50 horsepower type CW rpm motor through foote reduction gears as shown in figure 3 the kiln is elevated at the raw end so that as it rotators rota toes the mixture will travel toward the klinker end upon coming from the kiln the klinker falls about twenty feet into a pit to allow it to cool somewhat it is then elevated by the klinker elevator which is driven by the 71 horsepower rpm motor shown in figure 2 to an automatic scale and dumped into the storage bin from the klinker storage it is transferred by means of a locomotive crane with a clam shell bucket to a bin from which it is fed into the finish mill the locomotive crane is also used for mixing the klinker as it will vary somewhat in quality after being ground and analyzed by the chemical department it is ready for the packing house to which it is carried on oil 0 a belt conveyor over a weighing machine which automatically records the number of 0 1 barrels that pass from the storage bins from the storage bins the cement is taken to the sacking machines driven by a 15 horsepower motor A sack cleaner is westinghouse estin ghouse single phase y va hp volt 1725 rpm motor driving kiln slurry feed control dipper driven by a 7 horsepower rpm motor through a foote reduction gear arid and a 15 horsepower motor driven blower for collecting dust from the sacking and sack cleaning machines is also used the motors are of the alternating current volt 60 cycle three phase and were furnished by the westinghouse electric manufacturing company of east pittsburgh pennsylvania this plant was designed and built by L D gilbert and has been in operation over three years during which time no shutdowns to any an due have been experienced trouble with th the e electrical equi equipment piment furnished fure 1 it by the westinghouse company is a model plant from every standpoint int and is practically dustless |