Patent Application
20090249560
Not applicable
Not applicable
Various embodiments relate generally to a method a apparatus including a rotatable cylinder or drum for extracting liquid out of liquid absorbent goods received in the cylinder or drum during rotation at high speeds.
At the end of a wash cycle the liquid absorbent goods such as laundered items or textiles, there is a water extraction step in which the wet goods are rotated in a cylinder or drum about an axis to cause a portion of the water in the wet goods to be extracted by centrifugal force.
It is known by those skilled in the art that the degree or amount of extraction of liquids from laundered items or textiles in rotating extractors depends upon the amount of centrifugal force produced by high speed rotation of a cylinder or drum which causes the ejection of the fluid from the items.
In some machines of these types, typically washers/extractors, the cylinders or drums rotates about its axis at relative slow speeds during the initial cycles of washing and at high speeds during a final cycle in order to extract the liquid from the goods. The lower speeds range from less than 20 to 65 revolutions per minute (rpms) while the high speeds can reach in excess of 1,000 rpms. Most machines are designed to withstand the unavoidable vibrations due to the high speed revolution of the cylinder or drum. During such high speeds, liquid absorbent goods are plastered against the side of the rotating cylinder or drum.
Wet articles of laundered items or textiles, from their very nature are generally unevenly distributed originally (or subsequently become unevenly distributed during the extraction process) in the cylinder or drum of the extractor. Uneven load distribution can be called an “unbalanced” or “out of balance” condition (e.g., the center of gravity of the rotating load and cylinder or drum is not located on the rotational axis of the cylinder or drum). Accordingly, very rarely are the goods evenly distributed about the cylinder or drum, and this unequal distribution of weight will create an imbalance which if excessive can over time cause severe damage to the washer/extractor. The amount of out of balance can be a measure of the geometric displacement of the center of gravity in the cylinder or drum, or the location of liquid absorbent goods with the rotating mass or the oscillating force occurring on rotation as a result of the displacement of the center of gravity.
One of the problems with extracting liquid from laundered items is that a wash load can often be unbalanced creating vibration. Insuring that the wash load is evenly distributed prior to extraction or spinning is not always possible. Patents have issued that are directed to the problem of vibration that is induced by rotation of an extractor or clothes washer, wherein an out of balance condition exists. The following table provides examples of such devices that have been patented.
One embodiment relates to liquid extraction systems for laundered or otherwise cleaned articles where in the extraction of the washing, rinse, or other cleaning fluid from the articles is effected through the high speed oration of a cylinder or drum which is perforated or otherwise provided with means for fluid extraction from the cylinder or drum. U.S. Pat. No. 5,280,660 is incorporated herein by reference.
One embodiment provides a method of controlling (e.g., limiting) the extract speed of a clothes washing extractor that employs an accelerometer. When an extraction is to begin, the extractor increases in speed over time. The accelerometer is then used to measure an out of balance condition of the extractor as the speed gradually increases.
One embodiment provides includes the step of adjusting the speed of the extractor corresponding to the amount of out of balance that can be measured by an vibration analysis means, such as an accelerometer. Further, in one embodiment the rotational speed of the extractor can be limited to a pre-selected rotational speed value corresponding to a measured out of balance. Generally speaking, the measured out of balance will be between about 0 out of balance and an out of balance that is a maximum allowable out of balance for a particular machine.
In one embodiment, an out of balance sensor (which can be an accelerometer) generates an output voltage that is measured, the output voltage being a function of the amount of out of balance of the machine. This output voltage is transmitted to a controller that sets the rotational speed of the machine based upon the measured out of balance.
During rotation an uneven weight or load distribution can produce severe vibrations or unbalanced conditions in the cylinder or drum (and in the extractor) which can cause wear and tear on the components of the extractor, and premature failure. Such vibrations or unbalanced conditions can increase as the speed of rotation of the cylinder or drum increases. In many cases an undesirable amount of vibrations or unbalanced conditions occur during the process of increasing the rotational speed of the cylinder or drum, but before a desired rotational speed is achieved.
In other cases, a desired rotational speed of the cylinder or drum is achieved, but subsequently an undesirable amount of vibrations or unbalanced conditions arise (these subsequently occurring undesirable vibrations of unbalanced conditions could be caused by shifting loads in the extractor).
In other cases, a rotational speed (which had been previously limited from being increased because of an already existing undesirable amount of vibrations or unbalanced conditions in the cylinder or drum) can subsequently be increased because the previous undesirable amount of vibrations or unbalanced conditions was reduced or lowered. In this case of a subsequently reduced vibratory or unbalanced load condition, the rotational speed of the cylinder or drum can be increased until reaching the first of two conditions in the extractor: (a) reaching a desired speed of rotation, or (b) reaching a speed of rotation where again an undesirable amount of vibrations or unbalanced conditions occur.
One embodiment relates to the extraction speed of clothes washing extractors and more particularly to an improved speed limit controller for an extractor that removes water from laundered clothing and similar laundered items. In one embodiment is provided an improved method and apparatus for speed control of an extractor wherein the speed of the extractor is automatically controlled corresponding to an amount of out of balance that is measured by a sensor that is mounted to the extractor. In one embodiment the sensor can be an accelerometer.
For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:
In one embodiment a conventionally available machine extractor 10 is used. In one embodiment machine 10 is of more or less conventional construction adapted for use as a flexibly supported extractor. Machine 10 can include a stationary frame 12 and outer housing 13 yieldably mounted on frame 12. Support arms on the housing 13 can be mounted on resilient support means which are in turn suspended from plates on frame 12. The exact location and size of plates relative to respective support arms depends on the center of mass of outer housing 13, including all attachments thereto, inner cylinder or drum 22, the expected average mass of goods and absorbed water that will be received in inner drum 22, and the resiliency of the respective support means. Although outer housing 13 and inner cylinder or drum 22 are shown as being cylindrically shaped, these structures could be of any other suitable shape.
Inner cylinder or drum 22 can be mounted within housing 13 for rotation about its axis by means of a shaft at one end extending through a bearing carried within opening in the end of housing 13. The cylinder or drum 22 has an inlet opening in the end opposite of the end mounted on housing 13, along with perforations about its circumference. The inlet opening of cylinder or drum 22 sealingly and rotatably registers with opening 15 of housing 13 and is closed by a door 28 over opening 15.
A motor 33 (which can be a variable speed motor) can be operatively connected to cylinder or drum 22 and drive same at selected rotational speeds. In one embodiment goods are introduced into inner drum 22 through opening 15 and inlet opening 23, and after door 28 is closed, the washing cycle begins by introducing liquid through a liquid injection means (not shown) into outer housing 13 and rotating inner drum 22. During the washing and rinsing cycles, the rotational speed of inner drum 22 normally ranges from less than 20 to 65 revolutions per minute (rpms). During the wash and rinse cycles and prior to the extraction cycle, water is drained from outer housing 13 and inner drum 22 through a drain (not shown). After the drain cycle, inner drum 22 is rotated at speeds which could exceed 1000 rpms to extract the remaining fluid from the goods, during which, as will be described and to follow, the speed of the inner cylinder or drum 22 can be continuously controlled based on a measured out of balance condition.
In one embodiment, the means used for detecting and determining the magnitude and location of an out of balance condition can be a vibration detection device which is independent of a fixed reference. On acceptable device is a solid state accelerometer 110, such as a model number NAS-002G, manufactured by NovaSensor, located in Fremont, Calif., can be mounted on outer housing 13 to sense acceleration along a particular axis, and thus generate an electrical output that is a sine wave. The period of the sine wave is the time for the completion of one revolution of rotating inner cylinder or drum 22. The magnitude of the peak of the sine wave is proportional to the magnitude of an out of balance load of goods in rotating inner drum 22. Since accelerometer 110 is “reference point independent,” it will not be damaged by the excursion experienced by the flexibly supported outer housing 13.
In one embodiment, the accelerometer 110 can be mounted on door 28 on the front of outer housing 13 because, in this system configuration, the front end of outer housing 13 undergoes more movement relative to the back where more weight exists due to the motor 33 and all the other devices operating to rotate inner drum 22. Accelerometer 110 can be oriented to detect acceleration of outer housing 13 along the horizontal axis across the front of the housing. However, it could be placed anywhere on outer housing 13 to measure acceleration along any axis. Additionally, it can be placed in various other places on machine 10.
The general operation of the method and apparatus 10 will be described below.
In one embodiment, the extractor 10 is turned on, and the rotational speed of the cylinder or drum 22 is incrementally increased (by “DELTA S”), and the cylinder or drum 22 is rotated at such increased rotational speed for a specified period of time “t”.
In one embodiment the incremental increase of the cylinder or drum 22 (by “DELTA S”) is programmable by a user.
In one embodiment the incremental measurements are done in set periods of time “tn”. In one embodiment the set periods of time “tn” remain constant throughout operation of the extractor. In one embodiment the set period of time “tn” is one of the following times in seconds: 10, 8, 6, 5, 4, 3, 2, 1, 0.5, 0.25, 0.1, 0.05, 0.01, 0.005, 0.001, 0.0005, 0.0001, 0.00005, and 0.0001. In one embodiment the set period of time “tn” is a range between any one of above two specified times. In one embodiment the set period of time “tn” is programmable by the user.
During this specified period of time “tn” the out of balance condition (or vibratory load) “OBn” of the cylinder or drum 22 is measured using a vibration sensor (such as an accelerometer 110). The measured out of balance condition is compared to a specified range of maximum out of balance. If the measured out of balance “OBn” is lower than the lowest point of the specified range for out of balance, then the speed is incrementally increased again.
Such steps of incrementally measuring and increasing the speed where the out of balance condition is less than the specified range are repeated until either the measured out of balance condition falls within the specified range, or the measured out of balance falls above the specified range.
Falls within the specified range. At a set period of time “tn” the out of balance condition “OBn” of the rotating cylinder or drum 22 is measured and compared to the specified range. If the measured out of balance “OBn” falls within the specified range, then the speed is not changed.
Falls above the specified range. At a set period of time “tn” the out of balance condition of the rotating cylinder or drum 22 is measured and compared to the specified range. If the measured out of balance “OBn” is greater than the highest point of the specified range, then the speed is incrementally reduced.
Such steps of incrementally measuring and comparing the out of balance condition “OBn” to a specified range are repeated until the rotational cycle of the extractor 10 is completed. If the measured out of balance condition “OBn” is: (a) below the specified range, the speed of the speed of the cylinder or drum 22 is increased; (b) within the specified range, the speed of the cylinder or drum 22 is maintained (until possibly the next comparison step; and (c) above the specified range, the speed of the cylinder or drum 22 is decreased.
In one embodiment a limit on the maximum rotational speed is placed on the cylinder or drum 22 notwithstanding the fact that the out of balance condition “OBn” (or measured vibratory load) of the cylinder or drum is less than a specified amount. In one embodiment the maximum rotational speed limit can be programmed by a user. In one embodiment the maximum rotational speed limit can be a function of time (such as having a linear, parabolic function, step function, or other function).
In one embodiment the maximum rotational speed can be calculated assuming that the cylinder or drum 22 is not out of balance, and looking at other factors (beyond an out of balance condition of cylinder or drum 22) which may cause damage to the machine or extractor, or components of same. In one embodiment the maximum rotational speed in revolutions per minute can be about 1000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250, 200, 150, and 100. In various embodiments the maximum rotational speed can be a range between about any two of the above specified rotational speeds.
In one embodiment the speed of a cylinder or drum is limited to a percentage of a maximum rotational speed when the out of balance condition of the cylinder or drum 22 reaches a specified condition. In various embodiments the maximum speed is provided in the immediately preceding paragraph. In one embodiment the percentage is about 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 70, 65, 60, 55, 50, 45, and 40. In various embodiments the percentage can be a range between about any two of the above specified percentages.
In one embodiment a warning is given if the controlled rotational speed of the cylinder or drum 22 drops or falls below a specified minimum operating rotational speed. In one embodiment the minimum operating rotational speed can be programmed by a user. In one embodiment the minimum operating rotational speed can be a function of time (such as having a linear, parabolic function, step function, or other function).
In one embodiment the cylinder or drum 22 is stopped when the operating rotational speed falls below the minimum operating rotational speed. In one embodiment the cylinder or drum 22 is stopped when the operating rotational speed falls below the minimum operating rotational speed for a specified period of time “tmin”. In one embodiment the cylinder or drum 22 is stopped when the operating rotational speed falls below the minimum operating rotational speed for a specified number of times (or events). In one embodiment the specified period of time “tmin” can be programmed or set by the user. In one embodiment the user of provided the opportunity of overriding the shut off of the cylinder or drum 22.
In one embodiment, the extractor 10 is turned on, and the rotational speed of the cylinder or drum 22 is increased to a specified speed. During rotation of the cylinder or drum 22, during specified period of times “tn”, the out of balance condition “OBn” (or vibratory load) of the cylinder or drum is measured using a vibratory measuring device 100 (such as an accelerometer 110). The measured out of balance condition “OBn” is compared to a specified range of maximum out of balance. If the measured out of balance “OBn” is greater than the highest point of the specified range for out of balance, then the speed is incrementally reduced. After this first incremental reduction of speed, the above described steps at set periods of time measuring the out of balance condition “OBn”, comparing such out of balance condition “OBn” to an acceptable range of out of balance, and either decreasing the speed (out of balance greater than specified range), maintaining speed (out of balance within acceptable range), or increasing the speed (out of balance less than the acceptable range) in the other embodiments can be followed.
In one embodiment the maximum speed for the out of balance of drum or cylinder 22 can be a percentage of the design rated capacity of the machine. In one embodiment the maximum out of balance can be 20 percent of the design capacity of the machine.
An example of calculating the design capacity for being out of balance follows. The volume in cubic units for cylinder or drum can be calculated using the formula Πr2d where “r” is the radius of cylinder or drum 22 and “d” is the depth of cylinder or drum 22. In one embodiment the design rated capacity of a machine (in inch*pounds) can be calculated using the formula of volume of cylinder or drum 22 (in cubic feet) multiplied by the factor 4.75 pounds/cubic feet. In one example model extractor (model number 4226V6J) drum or cylinder 22 has a volume 20.8 cubic feet which provides (20.8 times 4.75) a 98.8 pounds in design rated capacity of the machine. 20 percent of 98.8 provides a 19.76 pounds out of balance figure.
In various embodiments the maximum out of balance in percentage of design capacity of the machine can be about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, and 50. In various embodiments an allowable range of out of balance (upper and lower numbers) can be between any two of the above specified percentages.
In one embodiment the acceptable specified range of out of balance is a point of out of balance “OBpoint”. In this instance where the range is a point it is expected that the rotational speed will be corrected (increased/decreased) most if not every time a comparison is made because it is unlikely that the exact amount of out of balance as specified as the point of out of balance will be measured most of the time.
If the measured out of balance condition is less than a specified amount, the rotational speed can be incrementally increased (by proceeding to step 1020), and then proceeding again to stop 1030.
If the measured out of balance condition is greater than a specified amount, the rotational speed can be incrementally decreased (by proceeding to step 1100), and then proceeding again to stop 1030.
If the measured out of balance condition is within a specified amount, the rotational speed can be maintained (by proceeding to step 1040) for a set period of time, and then proceeding again to stop 1030.
The above three choices of steps (1020, 1100, or 1040) can be continued until the end of the extraction process which is step 1050.
Point 300 shows the out of balance condition entering the acceptable range 220 of out of balance. Before this time the out of balance was below the lowest point in the range 210. Before this point the speed S was increasing (from time) to time at point 300/500. After time at point 300 speed S of cylinder or drum 22 is maintained at a constant speed (neither increased nor decreased) because the out of balance condition is within the acceptable range (steps 1030/1040 of flow chart 1000).
Operations within an acceptable range of out of balance occurs until the time at 310 where the out of balance condition moves out of the acceptable range (goes above upper level 220). After out of balance 310 is seen, the speed of cylinder or drum 22 is reduced in an effort to reduce the measured out of balance to within the acceptable range 220 (steps 1030/1020 of flowchart 1000). This occurs at point 320 which has a speed of 520. After time at point 320 speed S of cylinder or drum 22 is maintained at a constant speed (neither increased nor decreased) because the out of balance condition is within the acceptable range (steps 1030/1040 of flow chart 1000).
Operations within an acceptable range of out of balance occurs from time 320 to time 330 where the out of balance condition moves out of the acceptable range (goes below lower level 210). After out of balance 330 is seen, the speed of cylinder or drum 22 is increased in an effort to allow operation of extractor 10 at a higher (and more efficient speed) until the measured out of balance to within the acceptable range 220 (steps 1030/1100 of flowchart 1000). This occurs at point 340 which has a speed of 540. After time at point 340 speed S of cylinder or drum 22 is maintained at a constant speed (neither increased nor decreased) because the out of balance condition is within the acceptable range (steps 1030/1040 of flow chart 1000).
Operations within an acceptable range of out of balance occurs until the time at 350 where the out of balance condition moves out of the acceptable range (goes above upper level 220). After out of balance 350 is seen, the speed of cylinder or drum 22 is reduced in an effort to reduce the measured out of balance to within the acceptable range 220 (steps 1030/1020 of flowchart 1000). This occurs at point 370 which has a speed of 570. After time at point 370 speed S of cylinder or drum 22 is maintained at a constant speed (neither increased nor decreased) because the out of balance condition is within the acceptable range (steps 1030/1040 of flow chart 1000).
Operations within an acceptable range of out of balance occurs from time 370 to time 380 where the out of balance condition moves out of the acceptable range (goes below lower level 210). After out of balance 380 is seen, the speed of cylinder or drum 22 is increased in an effort to allow operation of extractor 10 at a higher (and more efficient speed) until the measured out of balance to within the acceptable range 220 (steps 1030/1100 of flowchart 1000). This occurs at point 390 which has a speed of 590. After time at point 390 speed S of cylinder or drum 22 is maintained at a constant speed (neither increased nor decreased) because the out of balance condition is within the acceptable range (steps 1030/1040 of flow chart 1000).
After time at point 390, the speed of cylinder or drum is maintained at the constant speed 590 because the out of balance condition does not move outside of the acceptable range. This continues (e.g., time 391, etc.) until the end of the extraction process which is step 1050.
One example embodiment in
The extractor 10 is driven to achieve a selected rotational speed (RPM) with a corresponding extracting force, multiple times gravitational force, such as 250 g's. In
The signal generated by the accelerometer 12 is transmitted to accelerometer board or connector board 113. The board 113 has software that enables threshold values to be set for each signal voltage value generated by the accelerometer (see chart 116). For example, a voltage of 2.90 VDC might equate to a 20 percent out of balance and the board 113 is programmed to have a corresponding threshold value of 215 g's (e.g., 215 times normal gravity acceleration). If the accelerometer 110 generates a voltage value that is higher than 2.90 VDC, the converter boa1rd 13 reads that signal and sends an output to a machine controller. The machine controller then tells the inverter 114 which rotates (drives) the extractor to stop accelerating.
In
Components 120 and 125 schematically indicate steps in the application of inverters. For 120 if F7 inverter. For 125 If GPD315 inverter. Component(s) 130 close(s) when inverter is above a set speed. Component 140 closes when balance board on accelerometer is not OK. Component 145 closes when balance limit is exceeded. Component 150 closes when processor desires to limit extractor speed.
The following is a list of reference numerals used in the application.
All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.
The foregoing embodiments are presented byway of example only; the scope of the present invention is to be limited only by the following claims.
Priority of U.S. Provisional Patent Application Ser. No. 61/042,436, filed Apr. 4, 2008, incorporated herein by reference, is hereby claimed.
| Number | Date | Country | |
|---|---|---|---|
| 61042436 | Apr 2008 | US |
