US 3106928 A
Description (OCR text may contain errors)
Oct. 15, 1963 B. RAND 3,106,928
MACHINED PARTS CLEANING APPARATUS HAVING AIR CONTROL SYSTEM Filed May 3, 1962 2 Sheets-Sheet 2 INVENTOR BURTON l-FA ND ATTORNEY United States Patent 3,106,928 MACHINED PARTS CLEANING APPARATUS 1 HAVING AIR CGNTROL SYSTEM Burton Rand, Bala Cynwyd, Pa., assignor to Autosonics Inc, Philadelphia, Pa, a corporation of Pennsylvania Filed May 3, 1962, Ser. No. 192,115 5 Claims. (Cl. 134-49) This invention relates to a cleaning apparatus, and more particularly, to a cleaning apparatus for removing grease and hydrocarbon deposits in addition to dirt from machined parts by treatment with solvents.
The cleaning apparatus of the present invention is an improvement over the cleaning apparatus set forth in my prior Patent No. 3,019,800. Experience has shown that the cleaning apparatus in my above mentioned patent adequately performs its intended function. I have now discovered that a cleaning apparatus of the type disclosed in my above mentioned patent need not be provided with a top wall and that a comparable efficiency may be obtained in preventing loss of evaporated solvent when an air control system in accordance with the present invention is incorporated therein. The air control system of the present invention may also be provided on other types of cleaning apparatus lacking a top Wall such as the cleaning apparatus disclosed in my copending application Serial No. 60,106 filed on October 3, 1960, now Patent No. 3,073,323, and entitled Cleaning Apparatus.
I have discovered that an air control system may be provided on a cleaning apparatus lacking a top wall regardless of whether or not the apparatus is provided with means causing the formation of a vapor zone above the level of the solvent. Tests performed on the apparatus in my above mentioned patent were run with and without the air control system of the present invention. When the air control system of the present invention was not utilized on a cleaning apparatus of the type illustrated in my above mentioned patent and lacking a top wall, the presence of vaporized solvent in the atmosphere was very noticeable. Such vaporized solvent in the atmosphere or fumes of vaporized solvent constitute a danger to operating personnel. When the air control system of the present invention was incorporated in the cleaning apparatus disclosed in my above mentioned patent, the presence of vaporized solvent in the atmosphere adjacent the cleaning apparatus was substantially eliminated.
In accordance with the present invention, an air control system is located at a point close to and above the level of the liquid solvent or the vapor zone thereabove. Conduit means are provided so that a mixture of air and vaporized solvent may be removed from the space in the apparatus above and adjacent to the vapor zone or liquid level. Such mixture is removed by means of a fan or pump which is coupled to the interior of the cleaning apparatus through a condenser. The condenser sepa rates the mixture into cool air and liquid solvent which is returned to the lower portion of the cleaning apparatus. The cool air is ducted to the opposite side of the cleaning apparatus and returned thereinto.
The cool dry air which is returned by means of an uninsulated duct to the opposite side of the cleaning apparatus is preferably returned at the same height at "ice which the mixture is removed. There is no heating of the returned air since it is desirable to have the cool dry air settle into the cleaning apparatus rather than rise out from the top thereof as would occur if the returned air were heated. When a cleaning apparatus is provided with means causing a vapor zone above the level of the liquid solvent, the air control system of the present invention is a supplementary control.
It is to be emphasized that the fan or pump of the present invention is extremely small. Hence, the circulation in the air control system is conducting a small volume of air on the order of five to thirty cubic feet per minute depending upon the size of the cleaning apparatus. As the size of the cleaning apparatus increases, the amount of air which is moved by the control system of the present invention increases. In all cases, the amount of air which is being moved is barely noticeable and may be referred to as a waft of air.
The present invention may be utilized in conjunction with cleaning apparatus of the type illustrated in my above mentioned patent or copending application wherein localized cavitation is provided by means of an ultrasonic transducer which generates downwardly toward the par-ts to be cleaned. In this manner, the contaminate which is removed from the machined parts cannot settle onto the transducer, but instead will settle on the bottom wall of the cleaning apparatus. Preferably, the machined parts to be cleaned are supported in a manner so that there is no conveying apparatus between the transducers and the machined parts which could interrupt the localized cavitation and thereby elfect'the efficiency of the ultrasonic cleaning effect.
The present invention provides an effective means for controlling dangerous or toxic fumes in such instances where a top wall on apparatus is impractical. For example, it is impractical to use a top Wall on a batch tank wherein the parts to be cleaned are lowered into and raised from the tank by means of an overhead hoist.
The National Conference of Industrial Hygienists has recently reduced the limits of toxic tolerance for degreasing solvents from 200 parts per million to 100 parts per million. Hence, it will be seen that there is a definite need for the present invention and that the importance, usefulness and desirability of the present invention are greater than they have been heretofore.
It is an object of the present invention to provide a cleaning apparatus having an air control system.
It is another object of the present invention to provide a cleaning apparatus lacking a top wall with an air control system thereby substantially eliminating the danger of fumes caused by vaporized solvent.
It is another object of the present invention to pnovide a novel air control system for a cleaning apparatus lack- '50 is fixedly secured to the shaft 42.
shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.
FIGURE 1 is a longitudinal sectional view of the cleaning apparatus of the present invention.
FIGURE 2 is a transverse sectional View taken along the lines 22 in FIGURE 1.
FIGURE 3 is a top plan view of the cleaning apparatus of the present invention.
Referring to the drawing in detm'l, wherein like numerals indicate like elements, there is shown in FIGURE 1 a cleaning apparatus designated generally as 1%.
The cleaning apparatus includes a housing designated generally as 12. The housing 12 includes opposite side walls 14 and 16. The side wall 14 extends for the full height of the housing 12. The side wall 16 extends up to a horizontally disposed portion 20. A side wall 18 extends from the horizontally disposed portion to the top of the housing 12. The housing 12 lacks a top wall and is provided with a bottom wall 24. The housing 12 also includes a front wall 22 and a rear wall 26.
A mechanical means is provided within the housing 12 to mechanically convey parts to be cleaned through the housing 12. Such means includes a stationary plate 28 which is supported by means of brackets 30 and 32. A pair of arcuate plates 34 and 36 are affixed to one surface of the plate 28. The plate 34 has one free end 34' and a second free end 34". The plate 36 has a free end 36' and a free end 36".
An arcuate plate 38 having an arcuate length greater than 180 degrees is spaced from and partially surrounds the plates 34 and 36. The plate 33 is secured to and extends from the periphery of plate 28.
A hearing 40 is fixedly secured to the plate 28 in a central portion thereof. The bearing 40 rotatably sup ports one end of a shaft 42. The other end of shaft 42 is rotatably supported by a bearing 44 fixedly secured to the inner surface of wall 14. A plate 46 is fixedly secured to the shaft 42 adjacent a central portion thereof. A plate 46 is juxtaposed to the plate 28 and is provided adjacent its periphery with a plurality of spaced rows of pusher vanes 48. The rows of pusher vanes 48 have a length slightly less than the distance between the inner arcu'ate plates 34 and 36 and the outer arcuate plate 38. 7
As seen more clearly in FIGURE 1, a driven sprocket A flexible belt or chain 52 extends around the driven sprocket 50 and a driving sprocket 54-. The driving sprocket 54 is fixedly secured to a shaft 56 extending from the motor 58. The motor 58 is conveniently mounted on the rear wall 26. The chain 52 and sprocket 50 do not require lubrication.
A pair of space'd parallel plates 60 are fixedly secured in any convenient manner to the top edge of Wall 22 of the housing 12. A roller 62 extends between the plates 60. A flexible belt 64 extends around the roller 62. The belt 64 extends around a driving roller (not shown) which causes the belt 64 to move and thereby convey machined parts to the cleaning apparatus 10.
A driven roller 66 is rotatably mounted on a shaft 68. which extends between the fixed inner arcuate plates 34 and 36. A crown-shaped plate 76 is fixedly secured intermediate the fixed inner arcuate plates 34 and 36. A driving roller 72 is rotatably. supported in any convenient manner and is rotated by a conventional motor means. A flexible belt 74 extends around the rollers 66 and 72, whereby rotation of the driving roller 72 causes the belt 74 to convey cleaned machined parts away from the cleaning apparatus 10. These parts are above the vapor zone and therefore do not require a separate lubrication system. 7 V
The roller 66 and the crown-shaped plate 70 are positioned intermediate the free upper ends 34' and 36 so that the belt 74 is crown-shaped at the point where the pusher vanes 48 move the clean machined parts thereon for conveyance away from the cleaning apparatus 10. The belt 74 is caused to assume a crown-shape between the ends 34- and 3 6 so that the clean machined parts will be positioned at the middle area of the belt 74 before the machined parts move out of the influence of the rotating pusher vanes 48. In order to attain this result, the speed of belt 74 must be correlated with the speed of the vanes 48.
The wall 18 is provided with an opening 76 and the fixed plate 23 is provided with an opening 78 through which the belt 74 extends. The openings 76 and '78 are of sufiicient size so as not to interfere with the clean machined parts being conveyed on the belt 74.
An immersion chamber 80 is provided within the lower portion of the housing 12. The immersion chamber 80 contains a cleaning solvent such as trichlorethylene or the like. A vapor zone 82 is maintained above the cleaning solvent in the immersion chamber 89. The interface between the vapor zone 82 and the solvent in the immersion chamber 80 is designated as 83. The upper limit of the vapor zone 82 is determined by the cooling coils 84 which extend around the inner periphery of the housing 12 at the level of the shelf 20.
A sump 86 is provided within the housing '12 and a heating coil 88 is positioned Within the sump 86. The heat from the heating coil 88 vaporizes the solvent within the sump 86 so as to maintain the vapor zone 82. The solvent within the sump 86 is maintained separate from the sol-vent within the immersion chamber 80 by an upright wall 89.
A plurality of ultrasonic transducers 90 extend from the inner surface of the plate 28 and are positioned between the ends 34" and 36" of the inner arcuate plates 34 and 36 respectively. The transducers 90 radiate downwardly toward the inner surface of the outer plate 38 so as to generate cavitation only in that portion of the solvent through which the machined parts will pass. It will be noted that the lower portion of the outer arcuate plate 33 is provided with a plurality of small holes or slots 91 so that contaminate may settle onto the bottom wall 24 of the housing 12.
The outer arcuate plate 38 is provided with a hole in the vapor zone 82 through which extends a nozzle 92. The nozzle 92 is connected to a pump (not shown) which in turn is connected to a trough (not shown) located below the cooling :coils 84. The nozzle 92 directs a stream of clean distillate at the machined parts after they have emerged from the solvent in the immersion chamber 84). The nozzle 92 is positioned so as not to interfere with the machined parts being pushed along the inner surface of the plate 38. If desired, the nozzle 92 may be in plate 36.
A platform 94 is secured to the front wall 22. A condenser 96 is supported on the platform 94. The condenser 96 has its inlet side in communication with the interior of the housing '12 above the vapor zone 82 by means of a conduit 98 which may be a manifold conduit. The outlet side of the condenser 96 is connected to the inlet side of a fan or pump 160'. A return condensate conduit 102 extends from the condenser 96 to a lower portion of the housing 12 in the area of the immersion chamber 811.
. The outlet side of the fan 100 is connected to a'conduit 102. The conduit 102 is uninsulated and extends along wall 14 to the wall 26 as shown more clearly in FIGURE 3. The conduit 102 may be supported by brackets 106. The conduit 162 may terminate in a pair of parallel branch conduits F168 and Md. The conduits 1G8 and are at substantially the same level as the conduit 98.
The operation of the cleaning apparatus 18 of the present invention is as follows:
Machined parts having adhering contaminate are posi tioned on the belt 64 in any convenient manner. Movement of the belt 64- causes the machined parts to fall off the belt 64 directly onto the outer surface of the inner arcuate plate 34. The machined parts to be cleaned are moved along the outer surface of the inner arcuate plate 34 by the pusher vanes 48. As the pusher vanes 48 move the machined parts through the vapor zone 82, the machined parts tumble due to gravity so that they are moved through the solvent in the immersion chamber 80 on the inner surface of the outer arcuate plate 38. As the machined parts move through the vapor zone 82, they are degreased. As the machined parts pass through the solvent in the immersion chamber 8i) on the inner surface of the outer arcuate plate 38, they are subjected to the cavitation generated by the ultrasonic transducers 99. At the lowermost point of the plate 38, the machined parts are out of the control of the vanes 48 for a short period of time. The ultrasonic transducers 90 are mounted directly above and adjacent the machined parts when they pass out of the control of the pusher vanes 48. At this point, the machined parts are directly subjected to the cavitation generated by the transducers 9d. The spacing between the pusher vanes 48 prevents any structure from interrupting the cavitation. Any contaminate removed from the machined parts will settle onto the inner surface of the outer arcuate plate 38 and pass through the holes or slots 91. Thereafter, the sediment will not be in a position to interfere with the cavitation generated by the ultrasonic transducers 9%.
While still being subjected to the cavitation generated by the transducers 99, the machined parts are moved by the pusher vanes 48 along the inner surface of the outer arcuate plate 33 out of the cavitation zone and through the vapor zone 82 on the lefthand side of FIGURE 2. As the machined parts pass through the vapor zone 82, they are subjected to a stream of clean distillate by the nozzle 92. The stream of distillate from the nozzle 92 rinses the machined parts. As the machined parts pass through the vapor zone 82, the temperature of the parts is increased so that the parts may dry more readily.
As the machined parts pass out of the vapor zone 82., they tumble due to gravity so that they are now being pushed along the outer surface of the inner arcuate plate 36. As the machined parts are moved beyond the upper end 36' of the inner arcuate plate 36, they are deposited on the belt 74. The pusher vanes 43 continue to push the machined parts so that the machined parts are at the middle portion of the belt 74 before the machined parts pass out of the influence of the pusher vanes 48. In order that the pusher vanes may continue to have an influence on the machined parts, the belt 74 is caused to have a crown-shape in the area between the upper ends 34 and 36' by the crown-shaped plate 70. The belt 74 conveys the clean machined parts away :from the cleaning apparatus 10 to any desired location. For purposes of illustration, the belt 74 is shown in FIGURE 1 as extending around rollers 66 and 72 which are supported on the housing 12. if desired, the driving roller 72 may be supported at a location spaced from the cleaning apparatus '10.
A mixture of air and vaporized solvent existing above the vapor zone 32 will be sucked into the condenser 96 due to the fan 100. The condenser 96 separates the mixture into liquid solvent and cool air. The liquid solvent is returned to the immersion chamber by conduit 102. The cool air will be forced by the fan 1% to flow through the conduit 1% and be discharged through the conduits 1&8 and 110.
The cool air discharging from the conduits 103 and 110 is directed toward the cleaned machined parts thereby accelerating the drying of entrained solvent. The temperature of the air returned by the conduits 108 and 110 is lower than the ambient temperature. Hence, the returned air will settle into the housing 12 above the vapor zone 82 rather than rise out of the open top of the housing 12. Due to the low capacity of the fan 101i, little or no ambient air from above the housing 12 will be sucked into the conduit 98. Likewise, little or no vaporized solvent from the vapor zone 82 will be sucked into the conduit 98. I have found that a manifold conduit arrangement such as the provision of conduits 98, 108 and 110 becomes increasingly desirable as the distance between the Walls 22 and 26 increases. The distance between these walls is sometimes less than two feet, then a single port in each wall is sufficient. The same relationship exists with respect to the length of the walls 22 and 26. When the length of these walls exceeds two feet, a manifold arrangement is more eflicient. The most surprising feature of the present invention is the fact that there is substantially no fumes in the area of the apparatus 16 and the amount of solvent lost due to escape of vaporized solvent is extremely small even though the housing 12 lacks a top wall.
As the cleaning apparatus 10 is utilized, there is a gradual build-up of contaminate and sediment within the immersion chamber on the bottom wall 24. A drain (not shown) may be provided so that the solvent within the immersion chamber 80 and the sediment may be removed. The cleaning apparatus 10 includes few moving parts so that it is not susceptible to needing any major repairs or overhauling. If desired, wall 26 or a portion thereof may be made removable so as to provide access to the interior of the housing 12.
It should be noted that the cavitation effect concentrates at certain levels called power nodes wherein the most effective cleaning is obtained. .The-arcuate path of the parts to be cleaned assures that the parts pass through the power nodes.
The present invention prevents delicately machined parts such as ball bearings from impinging against one another since they are separated by the vanes 48. The vanes 48 may be made of a material which is softer than the ball bearings so as to avoid flat spots which may be caused by the drop from the belt 64.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.
'1. In a cleaning apparatus for :degreasing machined parts comprising a housing having an open top, a mechanical means within said housing for receiving parts to be cleaned and for moving the parts through a portion of said housing adapted to contain a cleaning solvent, means coupled to said housing at a point above the level of the solvent adapted to be contained in said portion of said housing for removing a mixture of air and vaporized solvent and returning the air of said mixture in a cool state to said housing at substantially the same level at which the mixture was removed, whereby the amount of solvent lost due to vaporization and escape of fumes through the open top of said housing are reduced.
2. In an apparatus in accordance with claim 1 wherein said mechanical means includes fixed inner and outer plates, a rotary member having pusher vanes disposed between the inner and outer plates, and means coupled to said rotary member for rotating the same.
'3. In an apparatus in accordance with claim 1 including means within said housing providing a vapor zone below the level at which the mixture of air and vaporized solvent is removed by said last mentioned means.
4. In a cleaning apparatus in accordance with claim 1 wherein said last mentioned means includes a fan having its inlet side coupled to the interior of said housing through a condenser, a conduit extending from the opposite side of said fan, and said conduit being connected to said housing and operatively associated with said mechanical means so that cool air may be returned to said housing at a point wherein it may be directed at machined parts which have been conveyed through the solvent adapted to be disposed Within said portion of said housing.
5. In an apparatus in accordance with claim 1 wherein said last mentioned means includes a first manifold structure, a condenser, said condenser being in communication with said housing through said first manifold structure, a fan, the inlet side of said fan being in communication with said condenser, a second manifold structure, a conduit having one end coupled to the output side of said fan, the other end of said conduit being References Cited in the file of this patent UNITED STATES PATENTS 1,399,415 Taliaferro Dec. 6, 1921 1,725,059 Colby Aug. 20, 1929 2,860,646 Zucker Nov. 18, 1958 3,019,800 Rand Feb. 6, 1962