US2925821A - Apparatus for treating metal borings - Google Patents

Description

Feb. 23, 1960 w. D, MacDQNALD 2,925,821

APPARATUS FOR TREATING METAL BORINGS Filed Feb. 20, 1956 2 fleets-Sheet 1 CLEAN DRY, AND COOLED CUTTINGS Ward D. MacDonald ATTORNEY OILY METAL CUTTINGS Feb. 23, 1960 w. D. MacDONALD 2,925,321

APPARATUS FOR TREATING mam. BORINGS Filed Feb. 20, 1956 2 SheetsSheet 2 uvmvrm Wa r0! D, Mac Donald A TTORNE Y APPARATUS FOR TREATING METAL BORINGS Ward D. MacDonald, North Muskegon, Mich., assignor to Michigan Foundry Supply Company, Muskegon, Mich, a corporation of Michigan Application February 20, 1956, Serial No. 566,495

11 Claims. (Cl. 13465) This invention relates to apparatus for treating metal borings. More particularly, this invention relatesto apparatus for cleaning oily, metallic cuttings for use in making aniline or any other compound requiring clean iron particles.

Aniline (C H NH is a parent substance for making dies, drugs and other chemicals. It is made by the reduction of nitrobenzene with iron filings or borings, generically referred to herein as cuttings, with hydrochloric acid as a catalizer. This reduction process requires exceedingly clean iron cuttings. The source of such cuttings are foundries or other machine shops of which cuttings are a by-product from their boring, milling and other operations. In these operations, cooling and lubricating oils are used. This oil adheres to the cuttings, requiring the removal of same before the cuttings can be used in the aniline reduction process. This invention relates to the method and apparatus for cleaning this oil from the cuttings.

The only known method for cleaning such cuttings is to burn oil therefrom and then cool the cuttings by passing them through a zone surrounded by a cooling jacket through which water or other coolant is circulated. This previous type method and apparatus used has been unsatisfactory for several reasons. First, the oil content of the cuttings produced by. such apparatus has been comparatively high, thus adversely influencing the effectiveness of the iron in the reduction process. These prior apparatuses also have a relatively low production rate of three to five tons per hour. In passing through the cooling zone at the extreme temperatures of the cuttings, oxidation occurs, which also influences the efiectiveness of the iron in the reduction process. Such oxidation also results in great losses of iron particles. Losses of iron particles, particularly the fines is an unsatisfactory result from the high air currents passing through the cooling chambers.

Another disadvantage of previous apparatus is the required low oil content of the cuttings which can be handled by such methods. To my knowledge, other apparatus requires less than 1% oil content. Apparently, this is due to the extreme temperatures, fuel and time ,required to burn ofl? greater quantities, such temperature elevation requiring more fuel and more elaborate cooling equipment.

This invention is designed to avoid and eliminate these disadvantages of prior methods. Therefore, an object of this invention is to provide apparatus for faster cleaning of oily cuttings.

Another object of this invention is to provide apparatus for cleaning oily cuttings in which the resultant product has a low oil content and very little oxide or corrosion.

Still another object of this invention is to provide apparatus for cleaning oily cuttings in which the loss due to oxidation and loss of fines is appreciably reduced.

A further object of this invention is to provide apparatus for cleaning oily cuttings which, under certain connited States Patent ice ditions, will not require any fuel except to start the method, thus making the process exothermic.

Other objects of this invention will become obvious upon reading the following specification in conjunction with the accompanying drawings wherein:

Fig. 1 is a block diagram of my method schematically representing the various steps.

Fig. 2 is a side elevational view of my apparatus for carrying out the method.

Fig. 3 is an end view of the burner taken along the plane III-Ill of Fig. 2.

Fig. 4 is an end view of the mixer taken along the plane IV--IV of Fig. 2.

Fig. 5 is an end view of the dryer taken along the plane V--V of Fig. 2.

Briefly, this invention is concerned with apparatus for cleaning oily, metallic cuttings. The apparatus performs the steps of burning the oil from the cuttings and mixing 1 water with the cuttings after the oil has been burned therefrom. This mixture of water and cuttings is then passed through a drying zone, the cuttings being almost entirely cooled by the evaporation of the water. Thus, the heat removed from the cuttings is substantially equal to the heat of vaporization required by the water. The specific apparatus for performing this method comprises a burner having means for burning the oil from the cuttings as they pass therethrough. A mixer is provided for mixing water with the cuttings. The mixer passes the mixture of water and cuttings to a dryer where the cuttings are dried by evaporation of the water from the cuttings.

The steps performed by the apparatus of this invention as schematically illustrated by Fig. 1 comprises three main steps-bufning'of oil from the cuttings; mixing the hot cuttings with a predetermined amount of water; and

then cooling and drying the cuttings by the evaporation of the water therefrom.

In accordance with a broader aspect of this invention, the oil is burned from the cuttings by any conventional method. It is important that substantially all of the oil be evaporated from the cuttings and burned. To accomplish this purpose, I have found that the operating temperature of the burner should indicate from 700 to 1200 degrees F. In the conventional method, the burner is fired by fuel such as gas, oil, or other hydrocarbon fuels.

In passing the oily cuttings through the burner, the cuttings themselves should normally reaeh a temperature of 800 to 900 degrees F., at which temperature substantially all of the oil is evaporated from the cuttings and burned into waste gases.

Although conventional apparatus for burning the oil from the cuttings is used in a broader aspect of this invention, I havefound that a much improved result is obtained by my preferred and novel apparatus which causes initial auxiliary firing of the furnace by the addition of hydrocarbon fuel but eventually causes self-firing by the oil on the cuttings by passing excess oxygen and sufficient cuttings through the burner to provide enough fuel for firing the process. In order to accomplish this, I draw excess air through the burner supplying it with additional oxygen for completing the combustion of the oil.

In conventional burners of the size comparable to that of this invention, passing more than five tons of oily cuttings through the burner is extremely hazardous due to the large quantities of stored combustible material accumulating in the burner. These excess quantities of combustible materials, in the form of smoke, gases and suspended liquid hydrocarbons, frequently causeexplosions. I have found that when excess oxygen is supplied to the burner this hazard is eliminated. Such excess oxygen provides a self-firing, exothermic process rcquiring no additional fuel except that necessary for initially starting the process. The excess oxygen permits passing cuttings of high oil content, and greater quantities of such cuttings through the burner with resultant greater quantities of oil beingburned from the cuttings. My apparatus will process cuttings with any oil content, the greater the better. Older apparatus require cuttings of less than 1% oil. The oil content range of the cuttings resulting from my invention is from to 0.005%. My apparatus can handle fifteen tons per hour of cuttings as compared to three to five tons per hour in old methods.

By supplying excess oxygen as used herein, is meant the supplying of oxygen in quantities greater than that normally occurring in the burner. Therefore, forcing or drawing excess air through the burner supplies excess oxygen. Pure oxygen or oxygen in various degrees of concentration in a particular gas is satisfactory but cost prohibitive. This additional air can be injected or drawn into the burner at the front of theburnenat several points or any suitable location which proves to be successful in causing'more complete combustion of the oil on the cuttings. In my preferred form, the excess air is injected or withdrawn at the inlet end of the burner.

The next step after the oil has been burned from the cuttings is to mix the cuttings with water. The amount of water mixed with the cuttings is extremely important. The optimumquantity is that which whenrevaporated by the heat in the cuttings will cool the cuttings to the desired temperature.

. It is well-known that the B.t.u.s of heat required to evaporate water is equal to the heat required to raise the water to 212 degrees F. plus that required to evaporate the water. This can be expressed as follows:

Qw= w w w+ w w where Q =total quantity of heat; m =mass ofwater; L =the heat of vaporization of water; c =thermal capacity of water; and 't =temperature change of the water in rising to 212 degrees F. L =970 B.t.u.s per pound and c,,, 1 B.t.u. per pound.

This formula, disregarding the efiect of the ambient air, gives the quantity of heat required to evaporate a certain mass of water. Accordingly, if the quantity of heat present in the cuttings is known, the amount of water which the cuttings are capable of evaporating can be resolved. 1

The .quantity of heat present in the cuttings is expressed by the following formula:

In this formula Q =the quantity of heat present in the iron cuttings; m =mass of cuttings; c =the thermal capacity of the iron cuttings; and t =the drop in temperature of the cuttings.

Disregarding the very small effect which the ambient air has on the cooling of the cuttings, in the preferred form of the method of this invention the heat required to evaporate the water is equal to the heat lost by the cuttings. Thus, Q,,,=Q and m L +M c t =M c t Accordingly,

mlcc a uz w w Utilizing this formula and knowing the value of the factors therein, the mass of the water can be determined. Itisthis massof water upon which the optimum amount to be mixed with the cuttings is determined in accordance with the preferred form of this invention. A hypo'thetical problem will illustrate the procedure for detel-mining this amount of water.

-Suppose 100 lbs. of cuttings leave the burner and enter thernixer at IOOOdegrees F. andthe water mixed with the cuttings is at 60 degrees F. Also suppose the de- 4 sired resultant temperature of the cuttings is degrees F. The thermal capacities of water (c and iron (c are l and .15, respectively. The heat of vaporization L for water is 970 B.t.u. per pound. Neglecting the effect of the ambient air, the formula would read as follows:

m =l2+lbs.

in accordance wtih this calculation, 12 pounds of water is added to each 100 pounds of cuttings as they enter the mixer at 1000 degrees F.

Obviously, the ambient air has some efiect upon cooling the cuttings. The extent of such effect is very difficult to determine or predict. This cooling effect of the ambient air will decrease the amount of water required to cool the cuttings by the evaporation thereof and accordingly the quantity of water to be mixed with the cuttings may fall somewhat below the quantity as determined. by the above procedure. On the other hand, other ambient conditions such as the humidity, temperature, etc. may have the opposite effect of requiring more water than that determined by the above formula. Therefore, it should be understood that in accordance with the preferred form of this invention, the percentageof water to the Weight of cuttings may vary at least 25% more or less than the amount determined by the above formula. The quantity of water added to the cuttings in the above hypothetical case would their lie within the limits of 9 to 15 pounds of water per 100 pounds'of cuttings.

This mixture of Water and cuttings has the consistency of mortar. It will stand alone but is still wet. Thus, the entire cuttings are surrounded by particles of water and in the drying step the water withdraws the heat from the cuttings as it evaporates.

Although in the preferred form of this invention the amount of water to be added to the cuttings is 25% more or less than the greatest amount of water that the cuttings will evaporate as determined 'by the above formula, I have found that less satisfactory results, but better results than that obtained by previous type methods, is obtained by mixing with the cuttings water in quantities outside this preferred range. It should be understood, however,.that in all aspects of this invention the cuttings are cooled by some heat of evaporation. Water added to the cuttings in quantities greater than the preferred range must be less than the amount which by thermal capacity alone-will cool. the cuttings to a temperature of 100 degreesF. This upper limit is easily determined by the following formula:

Substituting the above hypothetical values for the factor in this formula, m becomes equal to:

100 .15X (1000- 100) i 1x40 In this hypothetical case, 338 pounds of water will absorb the heat in the cuttings solely by its' thermal capacity. Thus, it should be evident that a quantity less than 338 pounds requires some cooling of the cuttings by heat of evaporation. 'e

The advantage of adding less than this amount of water is that less additional heat is required to dry the cuttings. The extreme case is the preferred or optimum quantity of water wherein .the raising the water to 212 degrees F. and evaporating it utilizes all of the excess heat content of the cuttings, thus requiring no additional heatto dry the cuttings. The exact amount of water within the broad range depends upon the additional heat available at the operation site For example,- excess heat may be available for drying the cuttings, in which case it may be advantageous to cool the cuttings more quickly by adding more water and then drying the cuttings of that water which is not evaporated by the heat of the cuttings. The flue gases from the burner could probably be used for this purpose. In any event it should be realized that sufiicient additional excess heat is practically never available for evaporating all the water mixed with the cuttings. The heat in the cuttings usually evaporates most of the water. As a result, rarely, if ever, is it feasible to mix with the cuttings a quantity of water which will almost entirely absorb the heat in the cuttings by its thermal capacity alone. In cases, it is advisable to use water in quantities falling within the optimum range of limits as previously described.

The cuttings ultimately produced by this invention are cooled to a temperature of 100 degrees F. At temperatures exceeding 100 degrees F., the cuttings are subjected to oxidation which adversely influences the effectiveness of the cuttings for use in the aniline reduction process. In some cases, the temperatures of the cuttings can be 200 degrees F. but preferably should not exceed that temperature.

The temperature of the water, of course, has a great effect upon the amount of water added to the cuttings. This temperature is taken into account in the above formulas and thus the amount of water will change accordingly. The higher the temperature, the more water required and the lower the temperature the less water required.

The temperature of the cuttings also has an efiect upon the amount of water required. This effect is reflected in the above formulas and should be evident therefrom. Considering the hypothetical case set up above, in accordance with the broadest aspect of this in vention, water should be added to 100 lbs. of cuttings in quantities less than 338 pounds. In the preferred and narrow aspect of this invention, the amount of water added would lie in the range of 9 to pounds per 100 pounds of cuttings. In such hypothetical case, this invention also covers all quantities of water from 9.0 to 338 pounds per 100 pounds of cuttings.

The cooling and drying step is very simple and can be accomplished by several means. The purpose of this step is to expose the cuttings to the ambient air so that the water is permitted to evaporate therefrom. This is preferably accomplished without supplying any additional heat or high air currents. The cuttings are merely agitated to expose them to the air. My preferred amount of water added to the cuttings makes this possible.

0n the other hand, it is conceivable that if an additional supply of heat is available the water content can be increased and the additional heat supply utilized for helping to evaporate the water from the cuttings. It is preferred, however, that the evaporation be accomplished entirely by the cuttings rather than by any additional heat. It is believed that applying additional heat will result in greater oxidation of the cuttings thus adversely influencing the efiectiveness of the cuttings for use in.

the aniline reduction process. Using high air currents results in loss of fines which become entrained in such currents.

Apparatus Apparatus for performing the above operations is shown in Figs. 2, 3, 4 and 5. The burner 10, in this preferred apparatus, is a cylindrical drum. This drum 11, is inclined at an angle. It is supported by two cradles 12 and 13. The drum 11 has helical fins 61 extending throughout the entire length thereof for transferring cuttings inserted at one end to the other end. The drum is rotatably mounted on the cradles or pillars 12 and 13 by roller bearings mounted in bronze liners. The

6 cradles as shown are constructed of concrete but any type of cradle can be substituted therefore without departing from the scope of this invention.

The mechanism for rotating the cradle includes a gear ring 16 secured to the outer circumference of the drum 11. The gear ring is fixed to the drum and driven by a gear motor arrangement 17.

The top end 18 of drum 11 is open. The bottom. end 19 is closed by a funnel 20 (Fig. 3) secured to the cradle 13 by the straps 21. The funnel 20 has an opening 22 at its bottom through which the cuttings pass, by means of chute 29, from the burner to the mixer. It also has an opening 23 communicating with the waste fume stack 24. The funnel 20, waste fume stack 24, and chute 29 are held stationary by straps 21 while the drum 11 rotates.

At the open end 18, a conveyor 25 is provided for carrying the cuttings from a container 26 into the drum 11. A burner unit 27 extends into the end 18 to facilitate the burning or flashing of the oil as the cuttings pass through the burner.

The fume stack 24 leads to a separator or purifier 40, such as a multi-wash unit which is adapted to wash the waste gases removing any harmful or odorous gases. The unit 40 is conventional, consisting of a cylinder or stack 41, having a water inlet 42 and a waste outlet 43 at its top. The outlet 43 has a fan 44 therein which is sufiiciently large to draw air through burner 10, stack 24, and cylinder 41. The fan in this apparatus creates the draft through the burner 10, such draft providing the excess air which is so essential in a preferred form of this invention as previously described. The fan 44 also disperses the water throughout the cylinder 41 so that the water can work effectively in removing the undesirable gases.

An exhaust stack 45 communicates with the outlet 43 for carrying the fumes into the air streams normally occurring in the atmosphere.

The mixer 30 is constructed of a cylinder drum 31 freely rotatable on the cradle 32 in substantially the same manner as the burner 10. The drum 31 extends into the dryer 50 and is concentric therewith. Mixer 30 rotates on the roller bearings 33 which are in turn rotatably mounted in the bronze liners 34 (Fig. 4). The cylinder 31 has helical fins 62 at its inner surface for transferring the mixture of cuttings and the water from one end to the other. The receiving end of the cylinder .31 is closed by the plate 35 which is held stationary in respect to the cylinder 31 by the straps 36 secured to the cradle 32. Plate 35 has an opening 40 for the water supply pipe 37 and an opening communicating with the chute 29 extending to the burner 10. The plate 35, supply pipe 37, and chute 39 are all held stationary by straps 36 as the drum 31 rotates. The drum 31 is driven by motor 410, gear 42, and gear ring 43 (Figs. 2 and 4).

The dryer 50 is of substantially the same design as the mixer 30 and burner 10. It is a long, cylindrical, hollow member having helical fins 63 on its inner surface for transferring the cuttings from one end to the other. The cylinder 51 is supported by several cradlelike supports 52 having the roller bearings 53 and bronze liners 54 (Fig. 5). The cylinder 51 is driven by a mo tor 55 through the driving gear 56 and a ring gear 57 secured rigidly and fixedly to the outer circumference of the cylinder 51. The cylinder 51 is open at both ends. The mixer 30 extends into its receiving end so that the cuttings pass directly into dryer 50. The dispensing end is adapted to dispense the cuttings into a cart 69 or any other type conveying means.

In the preferred form of this invention, no exterior heat is applied to the dryer 50 and no high air currents are blown through the dryer. The drying is accomplished entirely by exposing the wet cuttings to the ambient air, thus causing the water on the cuttings to evaporate and withdraw heat from the cuttings. i

In its broadest. aspect, it may be desirable when more Water is used than that contemplated by my preferred form of this invention to pass the hot waste gases from the burner around the dryer, either in the form of a coil or a jacket surrounding the dryer. This additional heat would facilitate the drying of the chips if the contents of the cuttings were not suflicient to evaporate all the water. It should be understood that such practice is only contemplated within the broadest aspect of this invention and that within the preferred aspects the evaporation of the Water on the cuttings is accomplished substantially entirely by the heat of evaporation.

The burner 10, mixer 30, and dryer 50, as illustrated are different sizes. Burner 10 has a 42 inch diameter and 14 foot length. Good results are obtained by running it at 15 r.p.m.s which carries the cuttings through the burner in 1 minute and l'sec'onds. The mixer 30 is 3 feet long and 24 inches in diameter; It rotates at 60 r.p.m.s, thus carrying the cuttings through it in 5 seconds. The dryer 50 is 30 feet longand 36 inches in diameter. The cuttings are carried through it in 1 minute and 17 seconds as it rotates at 26 r.p.m'.s.

It should be understood, that although specific sizes and speeds of all these units have been given, that such sizes are not necessarily critical. Various different sizes and speeds can be used depending upon various conditions, including the amount of water and oil in' cuttings and the desired capacity. For example, the burner may be made longer if requiring a longer time to burn the oil from the cuttings. This, of course depends upon the oil content of the cuttings and the temperature ofthe'burner. Increase or decrease in the size of the burner may necessitate changing the size of the mixer and the dryer. The dryers size may be changed in accordance with the time required to dry the cuttings, which depends entirely upon the water content of the cuttings and water mixture.

Operation The operation of this apparatus is simple. First, the

motors for driving the burner, the mixture and the dryer 1 are set into operation, thus, rotating the various units. Then the flame from the burner nozzle, the excess air, and the cuttings are all simultaneously fed into the burner at the receiving open end 18. As the cuttings are introduced into the receiving end 18 of the burner 10, the heating flame from. the heater unit 27 is applied to raise the temperature of the chips. At the same time, excess air is drawn into the burner. Thisforrns a strong draft through the drum and also provides excess oxygen for facilitating a more complete combustion of the oil. I have found that with this apparatus, if more than 5 tons per hour of chips are passed through the drum and the oil content is high and the water contentlow, the heating flame is only necessary during the initial burning process. Thereafter, the oil on the chips furnishes enough fuel to sustain the temperature for flashing or burning of the oil from the cuttings. This is especially made possible by the excess air.

As the chips pass through the drum 11, the heat in the dI'L'tIIl causes all the oil to vaporize and to ignite in the presence of the excess air. Thus, the oil burns to clear waste products such as carbon dioxide, carbon monoxide and water vapor. These fumes are drawn through the fume stack 24 and then passed through the unit 40. The water injected at inlet 42 is dispersed throughout cylinder 41 cleaning the fumes as they pass upwardly and the water spray falls downwardly. The gas is drawn into and blown out of the exhaust stack 45 by fan 44. i V

As stated previously, it is conceivable that these gases which are at rather high temperatures can be used for supplying excess heat to the dryer 50. In the preferred form of this invention, however, these waste gases are merely discarded. p p H V The cuttings; as they pass through the burner, are

, shipment.

transferred to the dispensing end 19 by the rotation of the drum 11 and the helical fins 61. The fins 61, also agitate the chips thus exposing the oil for evaporation and burning. The inclination of the burner 10 also helps to transfer the cuttings from the receiving end to the dispensing end.

The cuttings 19, after all the oil has been burned off, pass through the chute 29 into the mixer 30. The cuttings at that time are at a temperature of approximately 800 to1200 degrees F. At this temperature, the cuttings are subject to oxidation, which is commonly referred to as rusting or corrosion. Thus, cooling such cuttings in the ambient air would have a deleterious efiect upon the cuttings for use in the aniline reduction process. In accordance with this invention, the cuttings and the water are introduced simultaneously into the receiving end of the mixer 30. Water can be sprayed either at such entrance or at the intermediate part, depending upon the various circumstances. The percentage by weight of water to cuttings is that previously discussed. In the preferred form of this invention, such ratio is calculated in accordance with the formula mtvc c m c t mwcwiw The water mixed with the cuttings results in a mixture which has the consistency of mortar. During the mixing step, inherently some of the water is evaporated, resulting in the lowering of the temperature of the cuttings. Also the cuttings temperature is lowered due to the thermal capacity of the water which rises to 212 degrees F. before evaporating. This entire mixing process takes about 5 seconds.

The mixture or slurry of cuttings and water passes into the dryer 50. The dryer 50 transfers the cuttings from the receiving end to the dispensing end. During such transfer the drum 51 constantly rotates and agitates the cuttings, exposing them to the ambient air. The chips or cuttings dry by evaporating the water thereon. The entire drying process takes about 1 minute, 17 seconds. I

At the exit or dispensing end of the drum 51, a cart 60 or other conveyance means is located for catching the cuttings which are then transferred to loading spot for packing into boxes or other containers ready for In operating the above described apparatus, the water required to cool a definite amount of cuttings to degrees F. was measured. It was determined that 172 pounds of water was required to cool 2000 pounds of cuttings whose temperature at the exit of burner 10 varied from 880-1020 degrees P. (930.45 degrees F. average). The temperature of the water mixed with the cuttings was 40 degrees F. and the ambient temperature 22 degrees F.

In accordance with the above formula the following quantity of water is required:

m c t uz at...

218 lbs. of water 9 It should be evident that the exact amount of water required in practice is 21% less than that theoretically required. This difference is explainable because of the cooling efiected by the 22 degrees F. ambient air and other conditions. The practical amount required does,

however, fall within the broad and narrow limits of this invention.

With this apparatus, I have found that I can more than triple the output of conventional methods for cleaning cuttings. My apparatus is also much less expensive to run and less complicated than other type apparatuses in which the cuttings are cooled by a cooler jacket.

With my apparatus, the loss due to oxidation and loss of fines is also greatly reduced. In older methods, 12% and above losses are very common while in my apparatus lo'ss is reduced to below 8%. This is due probably to the reduction in oxidation and also due to the reduction in loss of fines resulting from high velocity air currents being injected through the cooling chambers. Usually the velocity of such air currents exceeds the entraining velocity of the bulk of the fines, thus the currents carry the fines out of the cooling chamber, resulting in the loss of such fines. In my apparatus, I do not pass a high velocity air current through the drying chamber. The entire drying process is accomplished with the normal air running through such chamber. This is made possible by cooling the cuttings by the heat of vaporization of the water rather than having the air itself dry and cool the cuttings.

My invention also is more economical because after it is started, it does not require any additional fuel or flame for sustaining the process. Above 5 tons per hour, the oil content of the normal cuttings passing through the burner is sufiicient to fire the process, thus eliminating the need for any additional fuel such as oil or gas.

My invention under the right conditions is thus a selffiring exothermal process rather than an endothermic process. This is made possible due to the capacity of the unit which can handle 5 tons per hour of cuttings of high oil content and also due to the forcing of excess air through the burner, resulting in more complete combustion. In conventional burners, passing more than 5 tons per hour through them would be very hazardous because of the explosion possibilities.

It should be evident that my invention, both as to the method and apparatus, is entirely new and has many advantages over other methods and apparatuses for cleaning. cuttings. It should be understood that although I have described preferred method and apparatus for obtaining these new results, other equivalent structures and methods can be used without departing from the scope of this invention. Therefore, all such equivalent forms -will be considered within the scope of this invention unlessexpressly excluded by the appended claims.

I claim:

1. Apparatus for cleaning oily metallic cuttings comprising a. burner means having a combustion chamber with an inlet at one end and an outlet at the other; means for transferring said cuttings from the inlet to the outlet; meanscausing combustion of the oil on the oily cuttings for burningsaid oil off said cuttings as they'pass from said inlet to said outlet; a mixer having an inlet adapted to receive said cuttings after they pass out of said burner means outlet; a water source communicating with said mixer; means for regulating the amount of water per unit time flowing into said mixer; said mixer having means for mixing said cuttings with said water to form a slurry and transferring said slurry to a mixer outlet; a dryer having an inlet adapted to receive said slurry after it passes out of said mixer outlet; said dryer having means for exposing the particles of said slurry to the ambient air whereby said water on said cuttings evaporates and by the heat of vaporization required by such evaporation cools said cuttings.

2. Apparatus for cleaning oily metallic cuttings comprising a burner having an inlet at one end and an outlet at the other; means for transferring said cuttings from the inlet to the outlet; means for supplying excess oxygen to said burner in greater quantities than normally occurring in the ambient air; means for supplying combustible fuel to said burner whereby when ignited said oil is burned off said cuttings with the help of said fuel and excess oxygen; a mixer having an inlet adapted to receive said cuttings after they pass out of said burner outlet; a water source communicating with said mixer; means for regulating the amount of water per unit time flowing into said mixer; said mixer having means for mixing said cuttings with said water and transferring said mixture to a mixer outlet; a dryer having an inlet adapted to receive said cuttings after they pass out of said mixer outlet; said dryer having means for exposing the particles of said mixture to the ambient air whereby said water on said cuttings evaporates and by the heat of vaporization required by such evaporation cools said cuttings.

3. Apparatus for cleaning oily metallic cuttings comprising a hollow cylindrical burner housing having a combustion chamber with an inlet at one end and an outlet at the other; rotatable helical means for transferring said cuttings from said inlet to said outlet; means causing combustion of the oil on the oily cuttings for burning said oil on said cuttings as they pass from said inlet to said outlet; a mixer having an inlet adapted to receive said cuttings after they pass out of said burner housing outlet; a water source communicating with said mixer; means for regulating the amount of water per unit time flowing into said mixer; said mixer having means for mixing said cuttings with said water to form a slurry and transferring said slurry to a mixer outlet; a dryer having an inlet adapted to receive said slurry after passing out of said mixer outlet; said dryer having means for exposing the particles of said slurry to the ambient air whereby said water on said cuttings evaporates and by the heat of vaporization required by such evaporation cools said cuttings.

4. Apparatus for cleaning oily metallic cuttings comprising a burner housing having a combustion chamber with an inlet at one end and an outlet at the other; means for transferring said cuttings from the inlet to the outlet; means causing combustion of the oil on the oily cuttings for burning said oil off said cuttings as they pass from said inlet to said outlet; a hollow cylindrical mixer having an inlet adapted to receive said cuttings after they pass out of said burner outlet; a water source communicating with said hollow cylindrical mixer; means for regulating the amount of water per unit time flowing into said hollow cylindrical mixer; said mixer having rotatable helical means for mixing said cuttings with said water to form a slurry and transferring said slurry to a mixer outlet; a dryer having an inlet adapted to receive said slurry after it passes out of said mixer outlet; said dryer having means for exposing the particles of said slurry to the ambient air whereby said water on said cuttings evaporates and by the heat of vaporization required by such evaporation cools said cuttings.

5. Apparatus for cleaning oily metallic cuttings comprising aburner housing having a combustion chamber with an inlet at one end and an outlet at the other; means for transferring said cuttings from the inlet to the outlet; means causing combustion of the oil on the oily cuttings for burning said oil ofi said cuttings as they pass from said inlet to said outlet; a mixer having an inlet adapted to receive said cuttings after they pass out of said burner housing outlet; a water source communicating with said mixer; means for regulating the amount of water per unit time flowing into said mixer; said mixer having means for mixing said cuttings with said water to form a slurry and transferring said slurry to a mixer outlet; a hollow cylindrical dryer having an inlet at one end adapted to receive said slurry from said mixer; said dryer having rotatable helical means for exposing the particles of said 1'1 slurry to the ambient air and transferring saidmixture to the other end. i

6. Apparatus for cleaning oily metallic cuttings comprising a burner having an inlet at one end and an outlet at the other; means for transferring said cuttings from the inlet to the outlet; means for burning said oil oif said cuttings as they pass from said inlet to said outlet; means for supplying excess air to said burnerin greater quantities than normally occurring in the burner; means of supplying combustible fuel to said burner whereby when ignited said oil is burned off said cuttings with the help of said fuel and excess oxygen; a hollow cylindrical mixer having an inlet adapted to receive said cuttings after they pass out of said burner outlet; a water source communicating with said hollow cylindrical mixer; means for regulating the amount of water per unit time flowing into said hollow cylindrical mixer; a dryer having an inlet adapter to receive said cuttings after they pass out of said mixer outlet; said dryer having means for exposing the particles of said mixture to the ambient air whereby said water on said cuttings evaporates and by the heat of vaporization required by such evaporation cools said cuttings.

7. Apparatus for cleaning oily metallic cuttings comprising a burner having an inlet at one end and an outlet at the other; means for transferring said cuttings from the inlet to the outlet; means for burning said oil ofi said cuttings as they pass from said inlet to said outlet; means for supplying excess air to said burner in greater quantities than normally occurring in the burner; means for supplying combustible fuel to said burner whereby when ignited said oil is burned off said cuttings with the help of said fuel and excess oxygen; a mixer having an inlet adapted to receive said cuttings after they pass out of said burner outlet; a Water source communicating with said mixer; means for regulating the amount of water per unit time flowing into said mixer; said mixer having means for mixing said cuttings with said water and transferring said mixture to a mixer outlet; a hollow cylindrical dryer having an inlet at one end adapted to receive said cuttings from said mixer; said dryer having rotatable helical means for exposing the particles of said mixture to the ambient air and transferring said mixture to the other end.

8. Apparatus for cleaning oily metallic cuttings comprising a hollow cylindrical burner having an inlet at one end and an outlet at the other; rotatable helical means for transferring said cuttings from said inlet to said outlet; means for supplying excess oxygen to said burner in greater quantities than normally occurring in the ambient air; means for supplying combustible fuel to said burner whereby when ignited said oil is burned off said cuttings with the help of said fuel and excess oxygen; a mixer having an inlet adapted to receive said cuttings after they pass out of said burner outlet; a water source communicating with said mixer; means for regulating the amount of water per unittime flowing into said mixer; said mixer having means for mixing said cuttings with said water and transferring said mixture to a mixer outlet; a dryer having an inlet adapter to receive said cuttings after they pass out of said mixer outlet; said dryer having means for exposing the particles of said mixture to the ambient air whereby said water on said cuttings evap- 12 orates and by the heat of vaporization required by such evaporation cools said cuttings.

9. Apparatus for cleaning oily metallic cuttings comprising: burner means having a combustion chamber; a mixer; and a drier; means in said burner means causing combustion of the oil on the oily cuttings for burning said oil 01f said cuttings while passing through said combustion chamber; means for transferring said cuttings from said burner to said mixer; a water source communicating with said mixer; means for regulating the amount of water per unit time flowing into said mixer; said mixer having means for mixing said cuttings with said water to form a slurry; means for transferring said slurry from said mixer to said drier; said drier having means for exposing the particles of said slurry to the ambient air whereby said water in said slurry evaporates and by the heat of vaporization required by said evaporation cools said cuttings.

10. Apparatus for cleaning o'ily metallic cuttings comprising; burner means; a mixer; and a drier;.means in said burner means for burning said oil ofi said cuttings; means for supplying excess air to said burner in greater quantities than normally occurring in the burner; means for transferring said cuttings from said burner to said mixer; a water source communicating with said mixer; means for regulating the amount of Water per unit time flowing into said mixer; said mixer having means for mixing said cuttings with said water to form a slurry; means for transferring said slurry from said mixer to said drier; said drier having means for exposing the particles of. said slurry to the ambient air whereby said water in said slurry evaporates and by the heat of vaporization required by said evaporation cools said cuttings.

11. Apparatus for cleaning oily metallic cuttings comprising an elongated burner housing having an inlet end and an outlet end; means in said burner for conveying cuttings from said inlet end to said outlet end; means at said inlet end for starting combustion of the oil on said cuttings; and blower means for causing sufficient quantities of excess air to pass through said elongated housing from said inlet end to said outlet end for supporting the combustion of said oil from said inlet to said outlet ends.

References Cited in the file of this patent UNITED STATES PATENTS 620,355 Potter Feb. 28, 1899 935,477 Evans Sept. 28, 1909 1,207,512 Dickson Dec. 5, 1916 1,231,002 Dawson June 26, 1917 1,383,418 Needham July 5, 1921 1,580,723 Hapgo'od Apr. 13, 1926 1,901,803 Davis Mar. 14, 1933 1,912,810 Wechter June 6, 1933 2,288,980 Turin July 7, 1942 2,478,461 Connolly Aug. 9, 1949 2,538,057 Steele Jan. 16, 1951 2,673,081 Fay Mar. 23, 1954 2,717,845 Carter Sept. 15, 1955 FOREIGN PATENTS 128,065 Australia July 8, 1948

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