US2421806A - Cleaning method and material therefor - Google Patents

Description

June 10, 1947. F. R. PERRY CLEANING METHOD AND MATERIAL THEREFOR Filed April 14, 1944 "l llllllllll i Patented June 10, 1947 Turco Products, Inc., Los Angeles,` Calif., a corporation of California `Application April 14, '1944, No. 530,983

.4 Clliml. (Cl. 51-282) l My present invention relates to method and apparatus for cleaning by abrasives and to novel materials therefor.

The pistons, cylinders and other parts of internal combustion engines, for instance, become l covered with adhering carbonaceous deposits i which must be removed and which chemical solvents, vapor cleaners and mild alkali sprays are incapable of completely removing. Since many of such parts are usually made of aluminum alloys, strong alkali or acid solutions cannot be used upon them. While sand blasting is capable of removing such deposits, it cannot be safely employed because it produces surface pits and roughness which destroy the usefulness of the parts. Thus it has been necessary to remove such deposits by hand scraping and rubbing with abrasive wools and cloths, which operations are impracticable because of the length of time required to carry them out.

I have heretofore proposed the use, in air blast equipment, of small particles of starch killed dehydrated cereal grains, and while that material is eiIective in that it provides an effective cleaning operation, it is relatively' expensive in that the grain must be rst specially treated and in that the particles quickly become so pulveru lent or powdered that they are ineffective as an abrasive.

I have found that I can produce a highly eilicient cleaning operation by utilizing, in an air blast, a hard nut shell ground or cracked into particles of relatively small size. More particularly I have found that black walnut shells ground or cracked into relatively small particles to -be peculiarly suitable in that such material isrelatively inexpensive, plentiful as waste, is not suillciently hard to pit or roughen metal surfaces, although it is hard enough to produce an eective cleaning operation. Such particles also last through a large number of cleaning operations and produce substantially no dust.

It is therefore one of the principal objects of my present invention to provide a novel method of removing carbonaceous deposits from metal.

Another object is to provide a new and eiiicient abrasive cleaning material.

Another object is to provide a cleaning method and material using ground or cracked black wal-v nut shells or equivalent materials.

A still further object is to provide a novel apparatus for cleaning by air blasting.,

By way of explaining my invention, I shall now describe a particular embodiment thereof, although the invention in its broader aspects is not j oFFlcE L 2 it to be conflned to the details to be described since in its broader aspects as deilned by the accom-` penymg claims it is susceptible of being modi-` fied in manners which the following description will suggest to those skilled in the art.

For purposes of the following description I shall refer to the accompanying drawings, in which:

Fig. 1 illustrates in perspective some of the abrasive particles; l

Fig. 2 is a side elevation, partly broken away,

'of an apparatus embodying my invention;

Fig. 3 is an enlarged longitudinal section of the mixing element;

Fig. 4 is an enlarged section taken on line I-l of Fig. 2; and

Fig. 5 is a fragmentary enlarged section of the discharge end of the nozzle element.

In the drawing, Fig. 1, I show granules or pellets 5. formed by grinding or cracking the dried shells of black walnuts. While the size of the pellets may be varied somewhat, it is desirable that they be cracked or ground in such manner as to present relatively sharp edges and to a 10-30 mesh screen size, an'optiinum` size being 10-15 mesh. l

In carrying out my operation I prefer to utilize apparatus comprising a cabinet 1 open at its front and having bottom walls 8 which converge to an outlet neck 9. A work-supporting bracket Il may be secured in the cabinet and a suction conduit I2 communicates with the interior of the Acabinet at a point adjacent the bracket l0 through a aring portion l5. Conduit l2 communicates with the intake of a suction fan I1 of conventional construction and the discharge outlet I8 from the .fan leads to awaste depository not shown.

A conduit 20 has its inlet neck communicating with the outlet end of neck 9 through a damper member 22 to admit air to the conduit. As best shown in Fig. 4, the member 22 has a wall 2l provided with an opening 25 and adapted to be open and closed by rotatable damper 261.

The outlet end of conduit 20 communicates with a suction chamber C in a mixing chamber 30. The mixing member comprises a tubular medial portion 3| having a reduced diameter discharge end to receive a flexible hose 33. A nipple Il extends into the inlet end of the member 3U. having a restricted discharge passage I5 communicating with the bore of member 3U at one end of chamber C, so that air under pressure discharged through nipple 3l from a hose so communicating with a conventional compressor 3 SIwill create a vacuum in chamber C to draw the abrasive particles into the air line. A nozzle l is secured on the discharge end of the hose 33.

My cleaning method is carried out and the aD- paratus operates as follows:

f A supply of pellets is placed in the bottom portion of cabinet v1 and the article to be cleaned, here designated W, is placed upon the bracket l0 or it may be merely manually held in the cabinet. By opening the valve 45 controlling line 36, a stream of air under pressure passes from the compressor and is discharged onto the work W through nozzle I0. lThe vacuum created in chamber C draws the desired quantity of the pellets 5 through line 20 into the air stream, which pellets are projected against the work W with the force of the air stream. The quantity of pellets introduced .to the air stream depends, of course, upon the air pressure and upon the degree of opening of the damper 26. The pellets being relatively light in weight, too great a quantity of them would be drawn into the air stream if the damper Awere completely closed, and yet a sufficient air pressure must be used to project the pellets againstthe work with suitable abrasive force.

My apparatus is. of course, suitable for carrying out a cleaning operation wherein other types of pulverized abrasives are used which may be susceptible of being broken up into powder or dust form by impact with the work. Even with the use of pellets formed of ground or cracked dried black walnut shells some relatively small fragments will be broken off the main pellet form, which fragments are too small to be useful and which shouldmot be permitted to return to the storage supply of the pellets in the lower part of the cabinet. Thus, to prevent any powdered material from being returned to the main pellet supply in the lower' part of the cabinet, I provide conduit I2 and suction fan I 1, which fan will draw off any powdered material which does not readily drop into the lower part of the cabinet by gravity against the action of the suction fan, so that all pellets in the lower part of 4 'f Y the cabinet are maintained of suitable size for efiicient operation.

Pellets formed of cracked or ground dried nut shells, while suiciently hard to remove car-` vbonaceous deposits from metal, are sufficiently resilient that they do not pit orindent the metal. While I have found ground or cracked black walnut shells to be preferable, my invention in its broader aspects contemplates the use of pellets of other types ol' ground or cracked nut shells having equivalent characteristics.

I claim:

1. The method of cleaning metal articles which consists of projecting thereagainst a stream of uid under pressure carrying. in suspension therein, pelletized nut shells having the hardness of black walnut shells. f

2. The method of cleaning metal articles which consists of projecting thereagainst aA stream of iiuid under pressure carrying, in suspension therein, pelletized black walnut shells.

3. An abrasive material for use in air blasts for cleaning metal comprising pelletized nut shells having the hardness of blackwalnut shells.

4. An abrasive material for use in air blasts for cleaning metal comprising pelletized black walnut shells.

FRANK R. PERRY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,885,760 Peik Nov. 1, 1932 2,114,573 Rhodes Apr. 19, 1938 2,176,577' Tirrell Oct. 17, 1939 2,062,671 Lupo Dec. 1, 1936 2,185,262 Lupo Jan. A2, 1940 2,318,578 Balz et al May 11, 1943 2,271,537 Biggert Feb. 3, 1942 1,884,791 Mc/Crery Oct. 25, 1932 2,332,251 Parrish Oct. 19, 1943 1,184,894 Taylor May 30, 1916

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