US 3203013 A
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Aug. 31, 1965 B. A. BUSS LAUNDRY METHOD Original Filed Feb. 28, 1958 2 Sheets-Sheet 1 I F" CONTROL Z Z l o i E I: I l5 l7 FIG. 2
BENJAMIN ALVIN Buss ATTORNEYS.
1, 1965 B. A. BUSS 3,203,013
LAUNDRY METHOD Original Filed Feb. 28, 1958 2 Sheets-Sheet 2 INVENTOR. BENJAMIN ALVIN BUSS ATTORNEYS.
United States Patent 3,203,013 LAUNDRY METHGD Benjamin Alvin Buss, East Moline, 111., assignor to Ametek, 1:22., a corporation of Delaware Continuation of application Ser. No. 718,204, Feb. 28, 1958. This application Apr. 6, 1964, Ser. No. 357,402 4 Claims. (Cl. 8-158) This application is a continuation of application Serial No. 718,204, filed February 28, 1958, in the name of Benjamin Alvin Buss and now abandoned.
This invention relates to a method such as used in commercial laundries, and particularly to a method for washing and extracting liquid from clothes or the like.
It is desirable to be able to wash clothes or the like in a machine and then, after performing the various washing and rinsing operations, extract liquid from said clothes in the same machine. After the clothes have had most of the liquid extracted therefrom, they are normally processed by an ironing machine or are dried. It is desirable to extract as much liquid from the load as possible so that succeeding operations can be performed efficiently. If the load is rotated fast enough, sufiicient liquid can be extracted, but the difliculty is that the machine must be operated at such a high speed that there will be serious vibration problems requiring heavy machines and foundations. clothes are not distributed evenly in the machine. Further, the clothes may be undesirably creased or damaged at high speeds.
The index of extraction can be termed percentage retention which is the percent of moisture (water) retained in the extracted load. used as the reference herein for obtaining the percentage of retention index rather than a normalized to atmosphere dry weight. As an example, if the completely dried weight of the load were one hundred pounds and the extracted weight one hundred and fifty pounds, the percentage retention would be fifty percent.
One of the objects of the invention is to provide a method which will treat laundry so that the percentage retention will be significantly improved.
Another of the objects of the invention is to provide an arrangement in which washing and extraction can be carried out in a single machine without the use of objectionably high extraction speeds.
Another of the objects of the invention is to provide an arrangement wherein the washing and extraction of liquid can be carried out satisfactorily in a continuous cycie.
in one aspect of the invention, the machine used for effecting the washing and extracting method can employ a rotatable drum or receiver into which the load or laundry is placed. The drum may be of the open end type supported only at one end or it may be supported at both ends. If desired, the drum may be compartmented and may have the usual ribs or means for enhancing tumbling action of the clothes during washing. In preferred arrangement, the machine has a shell within which the drum is located, the shell being adapted to receive the various washing liquids and supplies. The shell may have a conventional dump valve means and may also include a fan or blower arrangement for removing or drawing air and vapor from the interior of the shell and drum. Motor drive means can be connected to the drum for rotating at a relatively low washing speed and then at extracting speed which will be above that at which clothes or laundry cling to the inside periphery of the drum. At extracting speed, the clothes will form a cake around the interior or inside periphery of the drum. Various arrangements can be employed for balancin the clothes as the transition is made from low to This especially is true when the Bone dry weight will be 32%,013 Patented Aug. 31, 1965 high speed so as to prevent destructive vibration at high speed, such as described, for example, in copending application Serial No. 680,067, now Patent No. 2,972,510 dated February 21, 1961.
Control means including switches, pneumatic arrangements or the like can be connected to motor control means and the valves for liquid, supplies, etc., so as to effect the desired cycle of operation. One example of a suitable means is illustrated in copending application Serial No. 356,665, now Patent No. 2,841,176 dated July 1, 1958. Such a control is shown in FIG. 3 for controlling the elements 15, 16, 19, 22 and 27 of FIG. 1.
In order to provide the desired extraction, steam is added to or injected into the clothes while they are clinging to the interior periphery of the drum as the drum is driven at extraction speed. Thus, steam is added while the clothes are rotating in a cake form against the interior periphery of the drum. In a preferred form, there is a short extracting period before steam is introduced so that some of the excess water will have been drained from the clothes. Then there will only be the residual liquid and clothes to be heated. By excess water is meant the water which is extracted before about a minute after the extractor has reached its top speed. The steam is fed to the machine so that at least a portion will be in a superheated state when introduced. This can be accomplished, for example, by supplying the steam at a pressure and temperature considerably above that of the interior of the drum.
After a predetermined time, the steam may be shut off and the drum still allowed to rotate. It can be theorized that the latent heat of vaporization of the steam or heat content thereof will be added to the cake which will assist in removal of liquid from the clothes as they are rotated. Thus, the cake will be heated while the machine is operating at extraction speed.
In a still further aspect, an exhaust fan means is connected with the shell which will help in the removal of the remaining liquid and vapors in the load so as to reach the desired retention point.
Following operation at extraction speed, the power can be shut off and the machine allowed to coast to a stop, the exhaust fan continuing running during this period. A tumbling period will be reached as the machine loses speed which will further condition the load. The dump valve also will serve as a means for access of cool air to the load inasmuch as it is desired to cool the same for handling purposes.
These and other objects, features and advantages of the invention will become apparent from the following description and drawings which are merely exemplary.
In the drawings:
FIG. 1 is an elevation partly in section of one form of the invention with the control system diagrammatically shown.
FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1; and
FIG. 3 is an exemplification of the type of control shown in FIG. 1.
The invention will be described in conjunction with a machine having a drum supported at both ends, but as previously mentioned, it could be used with an open end type washer.
Referring to the drawings, drum 10 may be supported on shaft 11 carried in bearings 12, 13 mounted on frame or shell 14 of the machine. Shell 14 is arranged to receive the liquid supplies of hot, cold or a mixture of hot and cold water through valve means 15.
Motor drive means 16 drives drum 10 through belt 17 and pulley wheel 18. Motor drive means 16 may be a multispeed motor or may be an arrangement having low and high speed motors (not shown) operable through clutch means as is known in the art. Also, the drum could be driven through any suitable variable drive mechanism.
Dump valve 19 is arranged to discharge water or liquid from the shell into sluiceway or passage 20. The dump valve may be of any suitable type such as that shown in U. S. Patent No. 2,443,816, or the arrangement shown in copending application Serial No. 719,099, now Patent No. 3,013,765, issued December 19, 1961.
Steam can be fed to the machine through line 21, valve 22, and a revolving joint in trunnion 23, such feeding steam to passage 24 in shaft 11. The steam is directed toward the clothes in the drum through suitable spaced and angled passages.
In the form shown, drum has a plurality of compartments with a triangular shaped compartment 25 at the center thereof as described in copending application Serial No. 718,677, now Patent No. 2,974,514, issued March 14, 1961. The walls 26 of the compartment have the usual apertures therein, those near center compartment 25 serving to permit steam to be carried out into the main compartment. Rotation of the drum will cause steam to be carried outwardly to the cake of clothes.
If desired, an exhaust fan arrangement 27 may be connected to the top of the shell, there being a motor 28 driving a fan located therein.
The front of each of the compartments of the drum may have suitable doors (not shown) for providing access thereto through the main door 29.
A control means, such as that described in US. Patent No. 2,841,176 referred to above, and illustrated schematically in box 30 can be employed to activate the various control elements in their proper sequence. This may consist of a plurality of cam operated switches actuated by a program control means as shown in FIG. 3. Thus, a timing motor 30B may rotate a cam shaft 30A on which are fixed cams 30C to 306 inclusive for actuating switches 30C to 306', respectively, thereby sequentially to energize and de-energize elements 15, 16, 19, 2.2 and 27 so as to perform the desired cycle of operations.
In normal operation, dump valve 19 first is closed and the machine operated so that the drum rotates at washing speed. Liquid and supplies are then introduced in the usual manner to carry out the washing cycle.
Following the washing cycle, the motor drive means or related equipment is operated to increase speed of the drum so that the drum will be driven at extraction speed above that at which the load clings to the inside periphery of the drum to form what may be called a cake. The speed may be held at an intermediate speed or can be gradually or sharply increased to full extraction speed.
As an example of operation, under normal washing conditions, the clothes will have a temperature of about 160 F. after Washing due to the last bath rinse being at a relatively high temperature. The drum preferably is rotated for a short period thereafter at the above-referredto intermediate extract speed so as to remove excess water and to assist in distributing the load uniformly to thereby provide a relatively even cake around the interior or inside periphery of said drum 10. After approximately 1 minutes, the drum 10 is rotated at high extract speed. As the drum speed approaches this high extract speed, most of the water which is easily removed from the large voids in the load is extracted. Valve 22 then can be opened by the control means 30, or otherwise, so as to cause steam to be injected into or to heat up the residual water in the load.
Since the drum or receiver 10 is now, in effect, an enclosed cylinder, except for small leaks through the seal of the main door 29, most steam and condensate must pass through the load. The first steam injected into the drum 10 replaces the air therein and some of it immediately condenses as it comes in contact with the relatively cool load. This condensate is at approximately 212 F. and immediately begins to pass through the load due to both centrifugal force and pressure created by restriction to the flow of steam through the closely packed, evenly distributed load in the form of a cake around the interior or inside periphery of the drum. As additional steam in contact with the inner surface of the load condenses, it also passes through the load as it is extracted. As the condensate penetrates the cake, the cake temperature increases with the interior surface being the hottest. As an example, with the final bath temperature of F. and after two minutes of steam injection, approximately one-half of the inner section of the cake is approaching 212 F.
As the steam condensate heats the load to a temperature approaching 212 F., a number of very important things occur. Thus, as the steam first enters the machine, it must condense or it must pass through the load as steam. That portion which condenses will be on the interior layer of the cake. Centrifugal force will cause this inner layer of condensed steam to push portions of the entrapped cooler water out of the load. The condensate will heat the fabric near the interior layer and continue to cool as it works its way to the perimeter during extraction, but will be replaced by new condensate which will end up at increasingly higher temperatures. That part which remains as steam in the interior of the drum will be at a slight pressure because the only means of escape is through the load and a very small percentage through the possible leakage through the seal of the door 29. This will result in a pressure differential which will cause part of the steam to flow through the load. On its Way through the load, most of this steam will condense and tend to further heat the cake.
The increased temperature of the cake during the extract period improves the result by decreasing the water retention. This result is made possible by a number of factors, all of which are directly related to the effect of temperature on the water and the load. Thus, the time required for a given quantity of fluid to pass through a given orifice under a given dilferential pressure is an accepted measure of viscosity. Lowering the viscosity of the water by raising its temperature shortens the time required for trapped water to pass through the weave of the cloth forming the load and results in improved extraction of excess water. Additionally, with the increase in temperature of the cake, the surface tension of the water in the fibers of the fabric forming the load is decreased. This, in turn, decreases the capillary action which will more readily release the retained water during centrifuging. Furthermore, during condensing, part of the original energy in the steam, called the heat of vaporization, is released on the inside surface of the cake or within the cake and becomes an important factor in the extraction process. Although superheated steam may also be used, saturated steam will release energy in the order of approximately 970 B.t.u. per pound of steam from 120 p.s.i.g. to atmospheric. This will heat about twenty pounds of water from to 212 F. per pound of steam. After the temperature approaches 212 F., the steam then tends to flow through the load as a gas, blowing water particles out ahead of it because of the pressure differential. Centrifugal force also may have an effect. After the desired temperature of the clothes has been reached due to heating by the steam, which for sea level conditions will be slightly below 212 F., very little additional steam will be needed thereafter to maintain the temperature.
As the extraction or percentage retention approaches fifty percent, only a small amount of steam thereafter will be used so that only a small amount of condensate must be extracted.
Normally, it is desirable to obtain in the range of 50%, depending upon extraction speed, retention value in normal practice. When such a very low retention is not required, it may be desirable to shut off the steam at a point where the rate of extraction is somewhat greater than the rate of condensate formed from the steam.
After steam is shut off, the drum can continue rotation at high speed and then the exhaust fan may be started so as to remove vapors from the machine at a high rate. The dump valve should be open at this time to provide a passage for air through the shell and through fan 27 to exhaust. Before the fan is started, this path for air also is available. The control 30 can then be arranged to shut off power or to start speed reduction so that the drum will begin a coasting or slowing period, the exhaust fan still operating to cool the load. At a lower or tumbling speed, the exhaust fan can be continued in operation so as to further condition the load. From the foregoing it is evident that the injection of steam during extraction is now available for conditioning during this tumbling or shake-out period, and additional moisture is removed from the load during this time by evaporation.
A brake may be used for stopping the machine, but this normally is only required for emergency purposes, for inching, or for slightly shortening the coasting period. Thus, wear of braking mechanism is minimized.
It can be seen that by use of steam, the temperature of the clothes is raised far above the normal washing temperature of 160 F. and since most of the excess water has been extracted before application of steam, a relatively small amount of the heat or Btu. in the steam will be required to heat the residual water and clothes.
It should be apparent that the use of steam, particularly if superheated, will afliect the values of vapor pressure in the water. As an example, if steam pressure of 100 pounds per square inch absolute is used, the temperature thereof will be approximately 328 F., whereas the temperature at normal atmospheric pressure is 212 F., so that the additional heat content or energy in the steam will -be available to evaporate Water in the clothes.
Examples of use of the principles of the invention are shown in the following runs in a 60" drum machine, the machine operating smoothly and the percentage retention ranging between 40 to 46 percent.
Test I II III Wash time min Total load, bone dry 3 compts lbs Low extract speed time, dump valve closed 146 may Thus, it can be seen that the use of steam at an elevated temperature to heat the load during extraction will result in significantly better percentage retention which is extremely important in conjunction with subsequent operations on the laundry. It should be apparent that details of construction and steps can be varied without departing from the spirit of the invention except as defined in the appended claims.
What is claimed is:
1. The method of laundering clothes which comprises performing several Washing and rinsing operations thereon within a drum in a composition consisting essentially of water by rotating said drum about a substantially horizontal axis at a slow washing speed, draining the washing and cleaning fluid, rotating said drum at an extracting speed to effect centrifuging the washed laundry to pack the laundry around the periphery of the drum and in the form of a hollow substantially cylindrical mass and to remove some of the excess water, and spraying steam around the interior surface of the packed laundry mass while it is being centrifuged while inhibiting the escape of steam from Within said drum, so that said steam continuously forms condensate over the inner surface of the packed laundry While it is being centrifuged, which condensate is forced by centrifugal force through said mass, said drum being rotated at a speed which produces centrifugal force which is exerted on the mass related to the duration of rotation at said extracting speed, duration of spraying steam around said interior surface, and the supply pressure of said steam, to attain a percentage of moisture retention in the range of about 40 to 50%.
2. The method of claim 1 including exhausting the vapors from around the exterior of said drum While said steam is being sprayed.
3. The method of claim 1 including rotating said drum at a slow washing speed after spraying said steam during said extracting speed of said drum.
4. The method of claim 1 including exhausting the vapors from around the exterior of said drum while said steam is being sprayed and rotating said drum at a slow washing speed after spraying said steam during said extracting speed of said drum.
References Cited by the Examiner UNITED STATES PATENTS 350,500 10/86 Price 62207 X 1,234,498 7/:1-7 Seymour 34- 5 8 2,556,303 6/51 Traube 6824 X 2,785,557 3/57 Stilwell 6824 X 3,102,407 9/63 Stilwell 6824 X FOREIGN PATENTS 691,467 5/53 Great Britain.
WALTER A. SCHEEL, Primary Examiner. WILLIAM I. PRICE, Examiner.