l ~ l a y .191j
T H E J 0U R
A L O F I N D 1's T RI A L, .A S D E S GI Y E E RI ATG C H E M I S 1'R E'
t h e air blast, also pre\-ents t h e sand from escaping, a n d t h e glassware is t h e n withdrawn. From t h e construction of t h e apparatus very little sand is blown out during the marking, even though high pressure is used. Where large quantities of bottles are t o be marked t h e cost of marking becomes a n important factor from t h e financial point of view, not only for time consumed, b u t also Tvith reference t o cost of t h e material. During t h e past year over twenty thousand ( 2 0 , 0 0 0 ) bottles have been marked a t a cost of less t h a n ten cents for sand and t w o dollars ( $ 2 . 0 0 ) for stencils, in addition t o t h e cost of compressing t h e air. T h e last item is t o be considered and varies in different locations. I n places where steam power is available, as in factories, creameries etc., t h e expense is scarcely t o be considered after t h e initial cost of installing an air compressor. Where only a limited number of bottles are t o be marked a h a n d compressor will ansiver quite n-ell; for rapid work the pressure need not exceed 2 0 t o 2 5 lbs. per sq. in. I t has been possib!e for an experienced man t o mark six t o eight gross per hour, in a very satisfactory manner. T h e sand blast requires no previous cleaning of glasslvare, as is frequently the case when marking with hydrofliioric acid.
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The fundamental design of this apparatus can be made use of in marking various kinds of glassware. Stencils can be easily made containing a greater number of letters or rows of letters. Stencils having plain openings may be used in etching laboratory glassware, beakers, necks of flasks, etc.. or for "spot" etching. PVRDUEU N I V E R S I T Y , LAFAYETTE. IKDIANA -~
A MODERN HYDRATED LIME PLANT B y RICHARD K. MEADE Received March 23, 1915
One of the newest hydrated lime plants is t h a t of t h e Dutchess County Lime Company, a t Dover Plains, N . T. This plant vias completed in t h e fall I I
D E S C R I P T I O S O F DRATVISGS
Fig. I is a brass receptacle of such dimensions as will accommodate the bottle to be etched or marked. This receptacle has a guide opposite t h e opening containing the stencil. T h e stencil is held in front of t h e piece of glassware t o be marked. b y t w o clamps. Fig. z shows plans of a n d elevations of the air-tight box which encloses all t h e etching mechanism. The spring (A\)through t h e medium of t h e roller (B) forces t h e guide a n d t h e bottle against t h e stencil. This rotation is obtained b y pressing t h e foot-lever (G) a n d is communicated through the bell-crank and rod ( H ) . The spring ( A ) is adjusted t o obtain the proper pressure of t h e bottle or piece of glassware against t h e stencil. The sand is blown from the nozzle ( D ) a n d forced against t h e stencil. T h e receptacle is rotated by means of the handle ( I ) sufficiently t o bring each letter of the stencil normal t o t h e blast of sand. T h e sand enters t h e nozzle i D ) through t h e opening (E) b y gravity. The compressed air enters through t h e valve ( F ) , n-hich is controlled by t h e foot-lever ( G ) :this one lever operating t h e valve (F) and spring (A) simultaneously. T h e sand entrance t o the nozzle is so located t h a t no sand escapes when t h e air pressure is removed. All t h e motions necessary t o mark each piece of glassware are controlled by t h e foot-lever simultaneously, except t h e rotation of t h e receptacle, t h e speed of which depends upon t h e depth t o which t h e glassware is t o be marked. All t h e sand blown into t h e box escapes through the opening ( K ) into a container. The sand is returned t o t h e sand box supplying t h e sand t o t h e nozzle. This sand box is placed two or three feet above t h e apparatus a n d t h e sand is carried by means of rubber tubing or small glass pipe t o t h e opening ( E ) of t h e nozzle.
FIG.I-PLANT
OF T H E
DUTCHESS COCNTYLrnE C O . , DOVERP L A I X SS, . T.
and has now been in operation for about four months. This company, however, has been in existence for several years, operating tJvo small kilns about two
FIG.2-LIME
KILNS D U R I N G CONSTRUCTION
miles from t h e town of Dover Plains, hauling their lime t o t h e railroad with teams and bringing the coal and other supplies t o t h e plant b y t h e same means.
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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
T h e stone found on t h e property is a high-grade magnesian limestone of which t h e following analyses give a good idea. ANALYSESOF LIMESTONE From old quarry From new quarry Silica.. ..................... 0.74 0.88 Iron oxide and alumina.. , , . , 0 . 9 2 0.90 Lime ....................... 31.04 30.74 Magnesia.. . . . . . . . . . . . . . . . . . . 21.03 21.11 Loss on ignition.. 46.31 46.64
.
............
T h e lime has been sold for years in New York City, Albany, Poughkeepsie a n d other cities along t h e line of t h e New York Central R. R. a n d enjoys t h e reputation of being a very high-class building lime. About a year ago, t h e company decided t o build a new plant consisting of both kilns a n d hydrating equip ment a n d commissioned the writer t o prepare p l a n s a n d specifications for this plant. I t w a s decided also t o locate t h e plant on a p a r t of t h e property adjacent t o t h e r a i l r o a'd, where the same quality of stone a s a t t h e old plant is found a n d t o extend a siding f r o m the r a i l r o a d t o t h e plant. A t t h e new site, t h e stone lies t o t h e south of t h e plant in a hill, having quite a considerable elevation, while a n ideal location for t h e mill was found on a level plateau immediately adjacent t o t h e hill a n d easily reached from t h e railroad. Work was begun upon t h e plant last winter a n d completed in t h e late summer. T h e general layout of t h e plant is shown in Fig. I . T h e kilns are located a t t h e end nearest t h e quarry; next comes t h e cooperage a n d barrelling department, t h e n t h e boiler room a n d t h e hydrating plant in t h e order named a n d finally a storage for hydrated lime, which latter is not yet completed. T h e kiln building is designed t o receive five, kilns, t w o of which are already in place. These kilns are
r"
Vol. 7, No. 5
of t h e general t y p e found throughout Llaryland a n d Southern Pennsylvania (Fig. z ) . T h e y have been modified, however, so as t o obtain both increased o u t p u t and economy over t h e latter. T h e kilns a r e equipped with two fire boxes, one on each side a n d a cooling cone below. T h e y also have a storage for stone in t h e upger p a r t of t h e kiln. T h e capacity of t h e kilns o n t h e stone found a t Dover Plains will average about 1 2 tons per day. T h e fuel ratio is about I of coal t o 4 of lime. Arrangements have been made t o install a belt conveyor t o carry t h e lime from t h e kilns t o t h e hydrating plant but at the present time t h e lime will be w h e e l e d from one t o t h e other. On e n t e r ing the hydrating plant, t h e lime is first p a s s e d through a Stu r t e v a n t open-door crusher (see Figs. 3,and 4). This reduces t h e lime to 3 such a size t h a t i t will all pass through aone-half inch screen, which is fine enough for hydrating purposes. From t h e crush e r the lime is elevated t o t h e third and t o p floor of t h e building into a large steel bin which holds about 20 tons of lime and is provided a t t h e bottom with a spout and gate, t h e latter being opened and closed b y a lever. Below t h e spout is located t h e weighing hopper and beneath this, t h e Clyde hydrator (Fig. s), which rests on t h e second floor: t h e scale box a n d indicator t o t h e water t a n k are also on this floor, so t h a t all t h e operations of t h e hydrator are controlled a t one point. T h e lime is weighed o u t in batches of zoo lbs. and dumped directly from t h e scale hopper into t h e hydrator. T h e water is measured in a t a n k beside t h e lime bin and is sprayed on the lime after t h e latter is introduced into the hydrator. T h e process of
hlay, 1915
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
hydration lasts a b o u t 2 0 minutes, although i t is probable t h a t when t h e plant is pushed for capacity t h i s t i m e c a n be shortened t o 1 5 minutes, a s t h i s lime h y d r a t e s very rapidly-particularly so for a magnesian lime. After passing t h r o u g h t h e h y d r a t o r , t h e lime is d u m p e d i n t o a large steel bin or hopper, capable of holding comfortably t h e charge from t h e h y d r a t o r , a n d provided a t t h e b o t t o m with a n a u t o m a t i c feeder which serves t o regulate t h e supply of lime going from t h e h y d r a t o r t o t h e pulverizer a n d is so a d j u s t e d * a s t o e m p t y t h e hopper before t h e new charge from t h e h y d r a t o r is ready t o be dumped. T h e lime falls from t h e feeder i n t o a screw conveyor which carries i t t o t h e pulverizer. F o r t r e a t m e n t of t h e lime after passing t h r o u g h t h e h y d r a t o r , t h e R a y m o n d system is used. T h e lime first goes t o a S o . I a u t o m a t i c R a y m o n d pulverizer (Fig. 6), located on the g r o u n d floor; t h i s mill is equipped with a throwo u t TT h i c h separates from t h e h y drate any large pieces of core or unhydrated lime left i n t h e p r o d u c t of the hydrator. F r o m t h e pulv e r i z e r the fine product is sucked u p b y means of a No. 11 f a n , and blown 1 into a 7 ft. d u s t collector located above t h e packing bin, as shown i n Fig. 3. I t will be noticed t h a t for t h e h y d r a t i n g p a r t of t h i s plant only one elevator is used, namely t h a t for carrying t h e lime from t h e crusher t o t h e lime bin. This is a feature of all t h e p l a n t s which t h e writer has designed, t h u s greatly simplifying t h e installation. I n connection with t h e cyclone dust collector t h e r e is also a t u b u l a r collector with 18 ft. tubes. This is designed t o catch t h e d u s t i n t h e exhaust from t h e R a y m o n d system. T h e product obtained from t h i s is so fine t h a t all of i t will pass a I O O mesh screen, a n d o n account of t h i s extreme fineness, it is suitable for t h e manufacture of grease a n d for other uses where a superfine h y d r a t e free from grit is necessary. Space has been left i n t h e building, a n d all arrangem e n t s made f o r adding another h y d r a t o r a n d separating system whenever it is desired t o double t h e capacity of t h e p l a n t , which has been designed with t h i s e n d i n view. F r o m t h e dust collector, t h e h y d r a t e , as we h a v e said,
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falls i n t o a bin above t h e packing machine. This l a t t e r is of steel plate supported on steel columns a n d holds 40 t o n s of h y d r a t e . A novelty in its construction is a partition dividing i t i n t o t w o parts. By a n arrangement of slides, h y d r a t e m a y be packed from either side with t h e same packing machine. This feature is designed t o allow t w o grades of h y d r a t e t o be m a n u factured a t once, t h e uniform product being obtained from t h e Fuller mill a s explained further on. T h e packing is done b y t h e Bates packer a n d Bates valve bags are used (Fig. 7 ) . This packer is now being equipped with a dust catching system which will remove practically all of t h e dust a n d will make t h e plant almost dustless. This system consists of a suction f a n connected with a pipe running along behind t h e packing machine. Branches with openings extend t o t h e t u b e s of t h e machine a n d t h e spill from t h e t u b e s is sucked away through t h e pipe. T h e d u s t is discharged i n t o t h e dust c o l l e c t o r of the Raymond system. ,1 f e a t u r e of t h i s plant is t h e equipment for pulverizing limestone. For t h i s purpose a 36 in. Fuller mill is employed and with i t almost any fineness desired can be obtained. TVh e r e t h e limestone is desired for agr i c u l t u r a1 purposes t h e mill is provided with a '/4 inch mesh woven wire screen. This gives a product sufficiently fine for f a r m requirements. At t h i s fineness t h e mill will grind a b o u t 5 t o n s of t h e Dover Plains dolomite per hour. T h e limestone t o be pulverized is passed through t h e same crusher used for t h e lime, goes u p t h e s a m e elevator a n d i n t o a screw conveyor which carries i t t o a bin over t h e Fuller mill. As t h e capacity of t h e crusher is 8 t o IO tons per h o u r , t h i s is amply large enough t o t a k e care of b o t h t h e h y d r a t o r a n d t h e pulverized limestone d e p a r t m e n t b y hydrating first on lime a n d t h e n on stone. T h e discharge from t h e Fuller mill is t a k e n u p b y a n elevator t o another bin a n d i t m a y be packed f r o m t h i s i n t o bags b y h a n d or i t can be spouted directly from t h e discharge of t h i s elevator i n t o t h e cars. There is also a n elevator leading from t h e throwout of t h e R a y m o n d mill. This t a k e s t h e tailings from t h e l a t t e r u p t o t h e bin above t h e Fuller mill (which l a t t e r
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T H E J O K R S A L O F I N D C ' S T R I A L A N D ENGINEERI,VG C H E M I S T R Y
bin has a special c o m p a r t m e n t for these tailings) where t h e y can be mixed with limestone a n d ground for agricultural purposes or t h e y can be mixed with fresh h y d r a t e ground a n d elevated i n t o one of t h e c o m p a r t m e n t s of t h e h y d r a t e packing bin. T h e idea of this l a t t e r arrangement is t o allow t h e making of a very fine h y d r a t e b y adjusting t h e R a y m o n d mill t o reject all b u t t h e finest h y d r a t e . ' T h e coarse material so rejected is t h e n ground in t h e Fuller mill a n d sold a s second-grade or mason's h y d r a t e . T h e t w o c o m p a r t m e n t s in t h e packing bin are t o allow t h e t w o grades of h y d r a t e t o be manufactured simultaneously. Figs. 3 a n d 4 show t h e general arrangement of t h e h y d r a t i n g plant. Power for driving t h e plant is obtained from a n AtlasCorliss engine which can develop about 13 j H. P. S t e a m for this is supplied from t w o water t u b e boilers which h a v e a r a t e d capacity of a b o u t 60 H.P. each. T h e machinery installed a t t h e present time requires a b o u t 7 j H . P., t h e additional power available being intended for t h e plant after its capacity has been doubled. Coal for t h e boilers is brought in on t h e south side of t h e plant on a n elevated t r a c k a n d dumped into a pocket opposite t h e boiler, while t h e coal pockets
T'ol. 7, NO. 5
columns. All t h e elevators are encased in steel a n d are of t h e chain bucket t y p e . T h e conveyors are of
FIG. RA RAYMOND P U L V E R I Z E R
t h e screw t y p e a n d work i n steel troughs. T h e main shafting is supported o n concrete piers, a n d clutches are used t o make t h e operation of t h e plant more flexible. T h e h y d r a t e d lime plant can be operated a t i t s full capacity with b u t five men a n d it is believed t h a t for quality of product a n d ease of operation it will not be surpassed b y a n y h y d r a t e d lime plant i n t h e country. ,411 plans a n d specifications for t h e h y d r a t e d lime plant were prepared b y t h e writer, who also drew plans
FIG. .%--THE HYDRATOR
f o r supplying t h e lime kilns are located further on along t h e same trestle. The coal is elevated t o t h e firing floor b y t h e use of a bucket elevator. T h e cars t o be loaded are brought i n on t h e n o r t h side of t h e plant a n d t h e platform from t h e bagging machine is on a level with t h e car floor. T h e kiln building is 6 0 ft. x j3 ft. a n d is of steel covered with corrugated iron. T h e firing floor is of concrete a n d steel a n d all of t h e ground floors througho u t t h e buildings are concrete. T h e h y d r a t o r building is 60 f t . x j3 f t . , of frame covered with galvanized iron a n d t h e construction throughout is of h e a v y mill-type. At t h e present time, a storehouse 53 f t . x I O O f t . is being built. This is of light steel construction a n d will be covered with galvanized iron. This storehouse is designed t o hold h y d r a t e d lime i n bags. It is t h e intention, however, very shortly t o p u t i n a steel t a n k storage- i n which t h e h y d r a t e will be stored i n bulk as manufactured a n d t h e n conveyed back t o t h e plant for packing, a s desired for shipment. T h e bins are all of steel a n d with t h e exception of t h e crushed lime bin are all supported on latticed
Fro. 7-BATES
VALVEBAGPACKING MACHINE
for t h e general arrangement of selected t h e mill site, prospected etc. T h e construction work was Ambrose Allen, superintendent of 202 NORTHCALVERT STREET MD. BALTIMORE,
t h e entire plant, t h e store deposits, i n charge of M r . t h e plant.
