US3079286A

US3079286A - Enclosed cold solvent spray cleaner

Info

Publication number: US3079286A
Application number: US177017A
Authority: US
Inventors: Thomas J Kearney; Bruce A Young
Original assignee: Detrex Corp
Current assignee: Detrex Corp
Priority date: 1962-03-02
Filing date: 1962-03-02
Publication date: 1963-02-26
Anticipated expiration: 1980-02-26

Description

Feb. 26, 1963 T. J. KEARNEY- ETAL ENCLOSED cow SOLVENT SPRAY CLEANER 2 Sheets-Sheet 1 Filed March 2, 1962 .& ,Jm Sm 5 WW? mam m m n. 87 1M 3 $9 W m. imi a w I N MmNNNN Feb. 2 6, 1963 1-. J. KEARNEY ETAI. 3,079,286

ENCLOSED COLD SOLVENT SPRAY CLEANER Filed March 2, 1962 2 Sheets-Sheet 2 FIZF: 3

a L/ 233 C INVENTORS.

T170017: J/Karae 6:.

BY Brave 1.701117 ATTORNEYS.

United States Patent ENQLGSED JOLD SOLVENT ShRAY CLEANER Thomas J. Kearney, Detroit, and Bruce A. Young,

Lathrup Village, Mich, assignors to Detrex Chemical industries, The, Detroit, Mich, a corporation of Michigan Filed Mar. 2, 15 62, Ser. No. 177,017 illairns. (Cl. 134-42) This invention relates generally to means for removing soils from the surfaces of work pieces, and particularly to improved apparatus for and methods of degreasing various utilities and electrical components.

, Vapor-type degreasers commonly include a vaporizing chamber or boil sump for the solvent and a vapor zone above the vaporizing chamber. They may also include a rinse or spray chamber in which liquid or vapor solvent rinses or sprays are installed in a desired arrangement. Such degreasers are commonly used for cleaning objects such as metal plates, castings, etc., which have become contwinated with grease, oil, dirt, metal shavings, and the like. In the cleaning of such objects, the high temperatures at which a vapor degreaser is operated are not harmful to the objects, but in the cleaning of many other objects such high operating temperatures must be avoided. For example, in the cleaning of assembled electric motors and certain types of resistors and capacitors, such high temperatures are likely to break down insulating materials and otherwise damage the objects. In addition, still other objects are unsuited for being cleaned by vapor degreasing by reason of the fact that it is unnecessary to resort to such high operating temperatures in order to do an effective cleaning job. Accordingly, an important object of the invention is to provide improved means for cleaning objects which have become contaminated with grease, oil, dirt, metal shavings, and the like, which objects are unsuited for being cleaned by vapor degreasing.

Another object is to provide such means which employs a liquid solvent spray phase followed by an air blow-oil phase with negligible loss of the solvent.

Another object is to provide such means wherein the spray liquid is maintained at a temperature ranging be tween cold and warm, at most.

Other objects of the invention will become apparent when the following specification is read with reference to the accompanying drawing, in which:

FIG. 1 is a schematic showing of a degreaser constructed in accordance with the invention; and

FIG. 2 is a schematic showing of the activated carbon solvent recovery unit.

The apparatus includes a cold solvent washer, generally designated 11), provided with an upright front wall 12, an upright rear wall 14, upright opposite side walls 16 and 18, a bottom wall 211 sloping downwardly toward the center thereof, and a horizontally extending top wall 22. The front wall 12 is fitted with a transparent access door 24-. Within the washer are a set of brackets 26 which support baskets 28. The washer is fitted With a lamp 30. Arranged within the washer are a multiplicity of nozzles 3-2 carried by a spray manifold 34 connected to a branch conduit 36.

The apparatus also includes a solvent storage tank, generally designated 38, having an upright front wall :0, an upright rear wall 42, upright opposite end walls 44 and 46, a horizontally extending bottom wall 43, and a horizontally extending top wall 50. Within the tank is an upright partition, generally designated 52, having an inclined apron 54. The partition 5-2 divides the interior of the tank into two reservoirs respectively designated 56 and 58. Extending from the end wall 46 is a flanged neck 69 fitted with a cover plate 62. Extending through the plate 6-2 and the neck 60 and into the reservoir 56 is a 3,0793% Patented Feb. 26, 1963 ice heating unit 63 connected to a steam supply line 6-4 fitted with a valve 66 which is connected to a thermostat valve control 68 in the reservoir 56.

A conduit 70 from the reservoir 56 is connected to the suction side of the pump of a pump and motor unit 72. The discharge side of the pump is connected to a conduit 74 which extends to a turboblower 76 mounted on top of the washer 10. The conduit 74 is fitted with two solenoid operated valves respectively designated 78 and 80-. The conduit branch 36 connects into the conduit 74 between the valves 78 and 8t Extending from the bottom 20 of the washer 10 to the end wall 44 of the storage tank 38 is a conduit 82 in which is connected a valve, generally designated 84, having a hinged valve plate 86 biased to closed condition by a counterweight 88. Extending from the side wall 18 of the washer 10 to the top wall 50 of the storage tank 3-8 is a vent line 99, and connected in the line 90 is a solenoid operated valve 91.

Extending from the side wall 16 of the washer is a conduit 92 connected to an exhaust fan 24. The fan is connected by a conduit 96 to an activated carbon solvent recovery unit 98. Depending from the conduit 92 is an electric motor 1114 provided with a shaft 106 which mounts a cam 1118. The cam works upon a follower 110 mounted upon a lever 112 which is connected by a link 114 to a damper 116 within the conduit 92.

The apparatus also includes a filter unit, generally designated 118, having a storage tank 120, a filter 122, an auxiliary filter 124, and a filter powder dispenser 126. The reservoir 58 in the storage tank 38 is connected through a conduit 128, a solenoid operated valve 131 and a conduit 132 to the storage tank 121). Extending from the storage tank is a conduit 134 connected to the suction side of the pump of a pump and motor unit 13-6 fitted with a pressurestat 13-7. The discharge side of the pump is connected through a conduit 13% and a solenoid operated valve to the bottom of the filter 122. Within the filter 122 are tubular mesh elements 142 coated with diatomaceous earth filter powder. The top of the filter 122 is connected through a conduit 144 and solenoid operated valves 146 and 147 to the front wall 40 of the storage tank 38, as shown. The conduit 138 is connected through a conduit 14-8 and a solenoid operated valve 151 to the conduit 144-, as shown. The bottom of the filter 122 is connected through a conduit 152 to the bottom of the auxiliary filter 124, which discharges through a conduit 154 into the storage tank 121?. The filter unit 118 is fully described in copending patent application Serial No. 105,379, filed April 25, 1961, in the names of Jack C. Smith et a1. (assigned to the assignee of the instant application), to which reference may be had for further details of the filter unit.

The apparatus also includes a solvent still, generally designated 160. The reservoir 56 of the storage tank 38 is connected by a conduit 161 to the suction side of the pump of a pump and motor unit 162. The discharge side of the pump is connected by a conduit 164 to the still 161 The still is fitted with a suitable heating unit 166 near the bottom thereof, a condenser unit 167 at the top thereof and a trough 169 under the condenser unit 167. The trough 169 slopes to one end of a conduit 168. The opposite end of the conduit 168 is connected to the pump of a pump and motor unit 170. The suction side of the pump is connected by a conduit 172 to the top wall 50 of the storage tank 38, through which it extends downwardly into the reservoir 56.

As stated hereinbefore, the conduit 96 is connected to the activated carbon solvent recovery unit 98. Referring particularly to FIG. 2, this unit comprises a lower section 178 and an upper section 180. The section 180 includes a pair of horizontally extending laterally spaced ducts 182, the rear ends of which are connected respectively to the conduit 96 and a diluting air intake 183 The fore ends of the ducts 182 are connected respectively to a pair of fans 134, which are actuated by a motor 185. The fans 184 discharge into a mixing chamber 135, which is connected by a collar 188 to a damper housing 1%. The housing 1% is connected by a collar 192 to a horizontally extending duct 194. The opposite end of this duct is connected to a condenser 196 by a collar 197. Within the damper housing 1% is a damper assembly 198 comprising a pivot shaft 2%, a lever 292 aifixed to the shaft, and damper plates 264 and 2% carried by the lever. Within the lower section 178 is a compartment, generally designated 2%, including a horizontally extending lower wall 21%, and an upright rear wall 212. Disposed in overlying spaced relation to the wall 210 is a screen 214 over which is a. deep bed 216 of activated carbon. Depending from the wall 210 is a damper housing 218 connected to a solvent free air vent 219. Within the damper housing is a damper assembly 220 including a pivot shaft 222, a lever 22% aifixed to the shaft, and a damper plate 225 carried by the lever. A steam line 2255 is connected to the upright wall 212 for supplyingsteam to the space between the horizontal wall 216 andv the screen 214. The condenser 1% is provided with a vent 239, a water inlet 232, and a water outlet 234. Immediately below the condenser is a suitable water separator 236.

In the operation of the apparatus, initially the

valves

78, 8b, 86, and 91 are closed, the lamp 30 is on, and the damper 116 is closed. The work to be cleaned is placed in the baskets 28. Then the door is closed, whereupon the cycle begins. Valve '78 opens, and pump 72 draws liquid solvent from the reservoir 56 and directs it through conduit 7d, conduit branch 36, manifold 34, and nozzles 32 onto the work in the baskets 28. After a predetermined period, in the order of about to 45 seconds, the valve 78 recloses and the valve 91 opens. Thus the liquid spray phase terminates and a drain phase begins. The fall-cit, i.e., solvent and soluble and insoluble soils, is drained to reservoir 58 through conduit 82 by gravity flow. When the head over the valve 86 reaches a predetermined height, the valve automatically opens against the influence of the counterweight and passes the fall-off, then recloses automatically under the influence of the counterweight. The pressures on opposite sides of the valve 86 are equalized by means of the conduit or vent 91 which places the interiors of the Washer 10 and storage tank 38 in communication. The draining operation may require about 10 to seconds.

The valve 91 now recloses, and the valve 86 opens, initiating the air blow-elf phase. Air is blown through the conduit 74, conduit branch 36, manifold 34, and nozzles 32 onto the work. The valve 86 remains closed under the influence of the counterweight 8%. Simultaneously with initiation of the blow-off operation, motor 1%, through cam 108, cam follower 110, lever 112, and link 114 opens damper 116,, whereupon the interior of the washer it) is vented through the activated carbon solvent recovery unit 93 to atmosphere. Upon termination of the blow-off period, the valve 80 recloses, cutting off the flow of air, and the motor 134 operates to reclose the damper 116 whereupon the cycle is completed. The air blow-oh. operation lasts for a predetermined period, in the order of 15 to seconds.

The fans 184 draw in vapor laden air through conduit 96 and diluting air through the intake 183. These separate streams of air are mixed in the chamber 186, from whence the air passes through the collar 188 and damper housing 1% into the chamber 2 Then the air passes downwardly through the activated carbon bed 216 and ,screen 214 into the damper housing 21%, from whence it passes to atmosphere through the conduit 21%. The solvent with which the air is initially laden is absorbed by the activated carbon.

densed at 167 and deposited in the trough 169.

Periodically, as required, the damper assemblies 1% and "20 operate, closing oil the collar 188 and the conduit 219, and a stripping operation begins. Steam is dis charged from the conduit 22% into the bottom of the compartment 298, from whence it passes upwardly through the carbon bed 216 and into the damper housing 1%. Then it passes through the collar 192, the duct 194 and collar 197 to the condenser 1%, which is vented at 23%. iiater is supplied to the condenser at 232 and discharged therefrom at 234. Thus the solvent laden steam is condensed, and the solvent is recovered in the separator 236, from whence it is returned to the still.

The filter unit 118 operates continuously. Solvent and soluble and insoluble soils ilow from reservoir 58 through conduit 128, valve 13% and conduit 132 to the storage tank 12%. At this time, the upper section of conduit 132 is closed oil by valves 13%? and 147. The pump at 136 draws liquid from the tank 129 and pumps it. through conduit 138 and valve 140 to the bottom of the filter 122. The liquid flows from the outside of the tubular elements 142 to the inside thereof, in consequence of which the insoluble soils collect on the exterior of the tubular elements 142. The solvent and the soluble soils pass through the mesh and through conduits 144 and valves 1% and 147 to the reservoir 56.

A backwash operation is initiated by the pressurestat 137 through controls, designated 174, when the pressure against which the pump 136 must work reaches a predetermined amount, due to the accumulation of soils on the elements 142. Thereupon valves 140 and 146 close and valve 150 opens. The flow is now through conduit 134, pump 136, conduits 138 and 143, valve 150, and conduit 144 to the top of filter 122. Then the flow is from the interior to the exterior of the tubular elements 142 and from the bottom of the filter 122 through conduit 152 to the basket 153 in the auxiliary filter 124. Thus the insoluble soils plus the filter powder coating are removed from the mesh of the tubular elements 14-2 and collected in the. revolving basket 153. The solvent and soluble soils are returned to the storage tank 128! through the conduit 154-.

Now a motor, designated 176, is actuated, and filter powder is added to the solvent. At the same time, valve 150 is reclosed, valves 149 and 146 are reopened, and valves 136 and 14-7 operate. The flow then is through conduit 134, pump 136, conduit 13S and valve 141 into the bottom of the filter 122. Then the flow is from the outside to the inside of the elements 142, through the mesh and to the top of the filter 122. Then the How continues through the conduit 144, valves 146 and 147, conduit 132 and valve 130 to the storage tank 12%. After a short time, the coating of filter earth is renewed on the mesh of the elements 142, whereupon the valves 130 and 147 operate again and restore the original circulation of liquid.

The solvent still operates continuously at a high distillation rate. Solvent and soluble soils are drawn from reservoir 56 through conduit 1161 by the pump at 162 and pumped through conduit 164 into the still 160, where they are heated by the unit 166. The solvent vapors which are generated rise in the still and are con- The pump at draws the distillate from the trough through conduit 168 and pumps it through conduit 172 to the reservoir 56 in the storage tank 38.

The temperature in the reservoir 56 is controlled by the thermostat valve control 68. The temperature is held to about 140 F. However, it may be cold instead of warm.

Any suitable solvent may be used, for example, methylene, chloride, methyl chloroform, trichlorethylene, perchlorethylene, or Freon.

The flow rates are arranged so that flow over the dam 52 is from the reservoir 56 to thereservoir 58.

The control system (not shown) is designed for suitable operation of the various elements of the system inpredetermined timed relation.

It will be understood, of course, that the present invention, as described and shown, is susceptible to various changes and modifications which may be made without any departure from the general principles or real spirit of the invention. Accordingly, it is intended to claim the present invention broadly, as well as specifically, as indicated in the appended claims.

Having thus described our invention, we claim as follows:

1. Degreasing apparatus comprising a first reservoir for liquids, a second reservoir for liquids, means providing a chamber for receiving work to be cleaned, an array of spray nozzles in said chamber, means for drawing liquid from said first reservoir and discharging it through said nozzles upon said work and alternately blowing air through said nozzles upon said work, means for draining liquid solvent and soluble and insoluble soils from said chamber into said second reservoir, an activated carbon solvent recovery unit, means for venting the interior of said chamber to atmosphere through said unit, means for drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and means for drawing liquid solvent and soluble soils from said first reservoir, distilling ofi said solvent and returning the same to said first reservoir.

2. Degreasing apparatus comprising a closed storage tank including a partition dividing the interior of said tank into first and second reservoirs disposed in overflow communication with each other, means providing a chamber for receiving work to be cleaned, an array of spray nozzles in said chamber, means for drawing liquid from said first reservoir and discharging it through said nozzles upon said work and alternately blowing air through said nozzles upon said work, means for draining liquid solvent and soluble and insoluble soils from said chamber into said second reservoir, an activated carbon solvent recovery unit, means for venting the interior of said chamber to atmosphere through said unit, means for drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and means for drawing liquid solvent and soluble soils from said first reservoir, distilling oil said solvent and returning the same to said first reservoir.

3. Degreasing apparatus comprising a closed storage tank including a partition dividing the interior of said tank into first and second reservoirs disposed in overflow communication with each other, means in said first reservoir for maintaining the contents thereof at a predetermined temperature below boiling, means providing a chamber for receiving work to be cleaned, an array of spray nozzles in said chamber, means for drawing liquid from said first reservoir and discharging it through said nozzles upon said work and alternately blowing air through said nozzles upon said work, means for draining liquid solvent and soluble and insoluble soils from said chamber into said second reservoir, an activated carbon solvent recovery unit, means for venting the interior of said chamber to atmosphere through said unit, means for drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and means for drawing liquid solvent and soluble soils from said first reservoir, distilling off said solvent and returning the same to said first reservoir.

4. Degreasing apparatus comprising a first reservoir for liquids, a second reservoir for liquids, means providing a chamber for receiving work to be cleaned, an array of spray nozzles in said chamber, a blower, a pump having its suction side communicating with said first reservoir and its discharge side communicating with said blower through a conduit having a branch communicating with said nozzles, valve means in said conduit operable for directing liquid pumped from said first reservoir to said nozzles for discharge therefrom onto said work and alternately directing air from said blower to said nozzles for discharge therefrom onto said work, means for draining liquid solvent and soluble and insoluble soils from said chamber intosaid second reservoir, an activated carbon solvent recovery unit, means for venting the interior of said chamber to atmosphere through said unit, means for drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and means for drawing liquid solvent and soluble soils from said first reservoir, distilling off said solvent and returning the same to said first reservoir.

5; Degreasing apparatus comprising a first reservoir for liquids, a second reservoir for liquids, means providing a chamber for receiving work to be cleaned, an array of spray nozzles in said chamber, means for drawing liquid from said first reservoir and discharging it through said nozzles upon said work and alternately blowing air through said nozzles upon said work, means for draining liquid solvent and soluble and insoluble soils from said chamber into said second reservoir including a normally closed valve controlled by the head of liquid over said valve, an activated carbon solvent recovery unit, means for venting the interior of said chamber to atmosphere through said unit, means for drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and means for drawing liquid solvent and soluble soils from said first reservoir, distilling ofl said solvent and returning the same to said first reservoir.

6. Degreasing apparatus comprising a closed storage tank including a partition dividing the interior of said tank into first and second reservoirs disposed in overfiow communication with each other, means providing a closed chamber for receiving work to be cleaned, an array of spray nozzles in said chamber, means for drawing liquid from said first reservoir and discharging it through said nozzles upon said work and alternately blowing air through said nozzles upon said work, means for intermittently draining liquid solvent and soluble and insoluble soils from said chamber into said second reservoir including a normally closed valve controlled by the head of liquid over said valve, and means placing the interiors of said closed storage tank and closed chamber in communication for equalizing pressures, an activated carbon solvent recovery unit, means for venting the interior of said chamber to atmosphere through said unit, means for drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and means for drawing liquid solvent and soluble soils from said first reservoir, distilling olf said solvent and returning the same to said first reservoir.

7. Degreasing apparatus comprising a first reservoir for liquids, a second reservoir for liquids, means providing a chamber for receiving work to be cleaned, an array of spray nozzles in said chamber, means for drawing liquid from said first reservoir and discharging it through said nozzles upon said work and alternately blowing air through said nozzles upon said work, means for draining liquid solvent and soluble and insoluble soils from said chamber into said second reservoir, an activated carbon solvent recovery unit, means operable for venting the interior of said chamber to atmosphere through said unit, said vent being open while air is being supplied to said nozzles and being closed while liquid is being supplied to said nozzles, means for drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and means for drawing liquid solvent and soluble soils from said first reservoir, distilling off said solvent and returning the same to said first reservoir.

8. The method of degreasing comprising subjecting the work to a spray of liquid solvent from a first reservoir and alternately to air blowoft', passing the blow-off air through an activated carbon solvent recovery unit, collecting the liquid solvent and the soluble and insoluble soils removed by the liquid solvent from the Work in a second reservoir, drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and drawing liquid solvent and soluble soils from said first reselvoir, distilling 05 said solvent and returning the same to said first reservoir.

9. The method of degreasingcomprising subjecting the work to a spray of liquid solvent from a first reservoir and alternately to air blow-off, passing the blow-off air through an activated carbon solvent recovery unit, collecting the liquid solvent and the soluble andinsoluble soils removed by the liquid. solvent from the work in a second reservoir, drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble 55 soils into said first reservoir, drawing liquid solvent and soluble soils from said first reservoir, distilling ofi? said solvent and returning the same to said first reservoir, and regulating the flow of liquid to and from said reservoirs to provide for unidirectional overflow from said first to said second reservoir.

10. The method of degreasing comprising subjecting the work to a spray of liquid solvent at a temperature substantially below boiling from a first reservoir and alternately to air blow-0E, passing the blow-off air through an activated carbon solvent recovery unit, collecting the liquid solvent and the soluble and insoluble soils re moved by the liquid solvent from the work in a second resenvoir, drawing liquid solvent and soluble and insoluble soils from said second reservoir, filtering out the insoluble soils and directing the solvent and soluble soils into said first reservoir, and drawing liquid solvent and sol-uble soils from said first reservoir, distilling oil said solvent and returning the same to said first reservoir.

Hood May 21, 1940 Kearney Jan. 4, 1955

Claims

8. THE METHOD OF DEGREASING COMPRISING SUBJECTING THE WORK TO A SPRAY OF LIQUID SOLVENT FROM A FIRST RESERVOIR AND ALTERNATELY TO AIR BLOW-OFF PASSING THE BLOW-OFF AIR THROUGH AN ACTIVATED CARBON SOLVENT RECOVERY UNIT, COLLECTING THE LIQUID SOLVENT AND THE SOLUBLE AND INSOLUBLE SOILS REMOVED BY THE LIQUID SOLVENT FROM THE WORK IN A SECOND RESERVOIR, DRAWING LIQUID SOLVENT AND SOLUBLE AND