How to adjust the spray arm speed

Abstract

To invent a method for allowing spray arm rotation speed to be regulated accurately.SOLUTION: A regulator includes a weight on a pivot and a fluid jet, the weight having a curved surface to produce a variable angle corner spray nozzle depending on the weight angle. Centrifugal force created during rotation of a spray arm pushes the weight outward, and increases as the spray arm rotation speed increases. The liquid jet is located out from a pivot point and pushes the weight inward. The pushing force of the liquid jet is maximum when the weight is most inward and minimum when the weight is most outward. The regulator stabilizes the arm speed at a specific speed, independent from center pivot friction and the spray arm nozzle's orientation tolerance. The arm speed stabilizes when centrifugal force on the weight is equal to the pushing force at a fluid jet port.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a spray arm for a washing machine for cleaning medical, pharmaceutical and / or laboratory instruments. How to adjust the speed and more particularly, to adjusting the rotational speed of the spray arms. [Background technology]

[0002] A washing machine, such as a dishwasher or a machine for cleaning and disinfecting medical, pharmaceutical and / or laboratory instruments, comprises a spray compartment into which a trolley for holding the items to be cleaned is introduced. One or more spray arms spray a liquid, such as water or other cleaning fluid, upwards and / or downwards at high pressure through spray orifices to wash and clean the instruments in the spray compartment.

[0003] Typically, the spray section has non-circular geometric features. For example, the spray section has a rectangular geometric feature, while the arm sprays in a circular pattern. As a result of the arm spraying in a circular pattern, the corners of the spray section may not receive enough (or any) cleaning fluid. Therefore, instruments placed in those parts of the spray section that do not receive enough (or any) cleaning fluid may not be adequately cleaned. To address this issue, additional spray nozzles are placed at the ends of the spray arms and angled to target the corners of the spray section. For example, the nozzles at one end may be angled slightly upward and the nozzles at the other end may be angled slightly downward. For low-pressure, high-flow systems, simple jets may be placed on the side of the spray arm near its tip. For high-pressure systems, angled spray nozzles are preferred to minimize flow.

[0004] Corner spray nozzles, such as these, create a force that rotates the spray arm due to the direction in which they spray the liquid cleaner. For effective cleaning, it is preferable to spray the cleaning solution at a high pressure and a predetermined speed. However, spraying the cleaning solution at such high pressures tends to result in excessively high spray arm rotation speeds, requiring a means to adjust the rotation speed of the spray arm. Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, the rotational speed of a spray arm is set by selecting a specific angle and pressure at which the corner spray nozzle sprays liquid cleaning agent. For example, a trial-and-error process of adjusting the tilt angle of the corner spray nozzle may be performed until the rotational speed of the spray arm falls within a desired range. However, this process can be time-consuming and difficult to achieve accurate results, especially for long spray arms that require slow rotational speeds. Furthermore, achieving slow rotational speeds using fixed / adjustable corner spray nozzles can be difficult due to manufacturing tolerances. [Means for solving the problem]

[0018] The method of the present invention allows for accurate adjustment of the rotational speed of a spray arm. According to the present invention, there is provided a method for adjusting the speed of a spray arm rotatable about an axis, the spray arm comprising: I) at least one nozzle; and II) at least one deflector pivotally mounted to the spray arm, the at least one deflector having a first surface proximal to the at least one nozzle with a curved portion and a second surface distal to the at least one nozzle with a chamfered portion, the chamfered portion and the curved portion being spaced apart from each other. shape defines an angle at which the fluid flow is dispersed relative to the direction of rotation of the arm, and the at least one nozzle is Towards The method includes ejecting a fluid from the at least one nozzle to Curved section applying a light beam to the spray arm generates i) a first force that pivots the at least one deflector toward the spray arm, and ii) a second force that rotates the spray arm about the axis, the rotation of the spray arm about the axis generating a third force that pivots the at least one deflector away from the spray arm, and at a predetermined rotational speed, the first force and the third force balance each other.

[0019] In one embodiment, the method further comprises adjusting at least one of a weight of the at least one deflector or a pivot position of the at least one deflector relative to the predetermined rotate Selecting for speed.

[0020] In one embodiment, the method further comprises: rotate For speed, Curved section The process includes determining the shape of the

[0021] In one embodiment, the third force is a centrifugal force.

[0022] In one embodiment, the curved portion of the first surface The fluid striking the nozzle forms a fan-shaped spray pattern.

[0023] In one embodiment, the fan spray pattern is between 10° and 90°.

[0024] In one embodiment, the second force increases as the deflector pivots toward the spray arm.

[0025] In one embodiment, the second force decreases as the deflector pivots away from the spray arm. [Effects of the Invention]

[0026] To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments, however, are indicative of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. [Brief explanation of the drawings]

[0027] The present invention may take the physical form of several patterns of specific components and arrangements of components, the preferred embodiments of which are described in detail in the specification and illustrated in the accompanying drawings which form a part hereof. [Figure 1] 1 is a side view of an exemplary washing machine to which the principles of the present invention may be applied; [Figure 2] 1 is a three-dimensional view of an exemplary spray arm according to the present invention. [Figure 3] 1 is a three-dimensional view of an exemplary deflector for adjusting the speed of a spray arm according to the present invention, showing the deflector pivoting away from the spray arm. FIG. [Figure 4] 1 is a three-dimensional view of an exemplary deflector for adjusting the speed of a spray arm according to the present invention, the deflector pivoting toward the spray arm. FIG. [Figure 5] FIG. 2 is a top view of an exemplary deflector for adjusting the speed of a spray arm according to the present invention, showing the deflector pivoting away from the spray arm. [Figure 6] FIG. 2 is a top view of an exemplary deflector for adjusting the speed of a spray arm according to the present invention, showing the deflector pivoting toward the spray arm. [Figure 7] 4 is a flowchart illustrating exemplary steps for adjusting the speed of a spray arm in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] Embodiments of the present invention will now be described with reference to the drawings, wherein like reference numerals are used throughout to refer to like elements. The figures are not necessarily to scale. Furthermore, the present invention finds utility in cleaning machines that use liquids to perform cleaning operations. Accordingly, the present invention will be described primarily in this context. However, the principles of the present invention may be applied to other types of devices and / or may use fluids (e.g., compressed air, etc.) instead of liquids as the primary medium.

[0029] As shown in Figure 1, a washer 10, such as a dishwasher or a machine for cleaning and disinfecting medical, pharmaceutical, and / or laboratory instruments, typically includes a spray section 12 for cleaning instruments. The spray section 12 includes at least one rotating spray arm 14. The spray arm 14 rotates about a vertical axis 14a to supply a liquid medium to instruments placed within the spray section 12. The liquid medium is supplied under pressure through a pump 16 and associated flow passages 18. A removable box 20 for holding instruments to be cleaned is positioned within the spray section 12 and is sprayed with cleaning liquid from the spray arm 14.

[0030] The spray arms 14 are supported on pedestals 26 attached to the floor of the spray section 12. The spray arms 14 spray cleaning fluid upwardly toward the instruments. In addition, another spray arm 14 may be suspended from an overhead support 26a and spray cleaning fluid downwardly toward the instruments.

[0031] Each spray arm 14 has an outlet nozzle 28 for spraying a predetermined direction of spray liquid. The predetermined direction of spray liquid is typically at an angle greater than 0° and less than 90° relative to the direction of rotation of the spray arm. The spray arms 14 are driven about their rotational axes 14a by the force of the liquid medium jets issuing from the spray arms 14 in the appropriate direction. Additional details regarding the cleaning machine 10 can be found in U.S. Pat. No. 7,841,104, which is incorporated by reference in its entirety.

[0032] As will be appreciated, the arrangement of the cleaner 10 and spray arms 14 can take many forms, and the above-mentioned embodiments are merely illustrative of some ways the cleaner may be configured. For example, the cleaner may include spray arms mounted on a movable trolley. In yet other embodiments, an open configuration may be implemented (e.g., without walls) in place of the spray section 12. Such an "open" embodiment may be practical in industrial environments where large objects are to be cleaned.

[0033] Conventionally, the rotational speed of the spray arm 14 is set by selecting a specific angle and pressure at which the corner spray nozzle sprays liquid. This method does not produce consistent results due to manufacturing tolerances. Furthermore, this method is time consuming and can become difficult to obtain accurate results as the length of the spray arm increases.

[0034] The rotation speed of the spray arm is controlled by the fixed radius of the spray arm according to the present invention. Curved section The liquid flow is adjusted using a pivotally mounted liquid flow deflector having a deflector angle. As will be described in more detail below, the liquid flow from the nozzle is deflected at different angles relative to the direction of rotation of the spray arm depending on the pivotal position of the deflector relative to the liquid nozzle. The angle of the liquid flow relative to the direction of rotation of the arm can be varied relative to the direction of rotation of the arm, so that the "pushing" force (which rotates the arm) generated by the liquid flow can be varied. In this respect, Curved sectionThe liquid sprayed from the nozzle Curved section The deflector is configured so that the pressure generated by the air hitting the nozzle increases as the deflector pivots toward the arm. Curved section The pushing force of the liquid hitting the deflector decreases as the deflector pivots away from the arm. As will be explained later, the liquid flow hitting the deflector tends to pivot the deflector toward the arm (creating the greatest "push"), and as the arm rotates, centrifugal force tends to pivot the deflector away from the arm (reducing the "push"). These two forces balance at a predetermined rotational speed.

[0035] For example, when the spray arm is initially in the stopped position, liquid is sprayed out from the nozzle at the end of the spray arm at a predetermined pressure. Curved section The first force strikes the deflector, causing it to pivot toward the spray arm. At the same time, the ejected liquid is deflected obliquely relative to the direction of rotation of the arm, generating a second "pushing" force. While the deflector is pivoting toward the arm, the pushing force is at its maximum, causing the arm to accelerate. As the arm's rotational speed increases, centrifugal force causes the deflector to pivot away from the spray arm. The centrifugal force is determined by the deflector's weight and the arm's rotational speed. As the deflector pivots away from the arm, the angle of the liquid flow relative to the direction of rotation changes, reducing the second "pushing" force. The arm's rotational speed stabilizes when the first force and the third force are balanced.

[0036] Referring now to FIG. 2, shown is an exemplary spray arm 30 according to the present invention in an "open" configuration (i.e., not within a spray compartment as in FIG. 1). The spray arm 30, rotatable about an axis 14a, has a base 32 mounted on and rotatable relative to a support 31, a first arm portion 34a mounted on the base 32, and a second arm portion 34b mounted on the base. The second arm portion 34b is radially opposite the first arm portion 34a. With further reference to FIGS. 3 through 6, a first nozzle 28 is disposed at an end 36 of the first arm portion 32a. A deflector 38 is pivotally connected to the first arm portion 32a at a pivot point 40. In the illustrated embodiment, the pivot point 40 is located radially inward relative to the nozzle 28. That is, the distance from the pivot point 40 to the base is less than the distance from the nozzle 28 to the base 32. Thus, the deflector 38 is positioned adjacent the nozzle 28 to receive the liquid stream emitted from the nozzle 28 .

[0037] As described herein, the deflector 38 is best seen in FIGS. Curved section In addition, the deflector 38a is located away from the nozzle 28. surface has a chamfered portion 38b. Curved section 38a of The height is lowest at the front of the deflector 38 and increases toward the rear of the deflector. In the illustrated embodiment, the chamfer 38b is approximately halfway toward the rear of the deflector 38. However, the chamfer may be located at a different position along the deflector 38 or may extend completely to the rear of the deflector 38.

[0038] Curved section The radius of 38a and chamfered portion 38b defines the angle of the dispersed liquid flow relative to the direction of rotation. From this point, when chamfered portion 38b is at its thickest, Curved sectionThe height of the chamfer 38b is at its highest point (the center rear of the deflector 38), causing the liquid flow to be deflected at a larger angle relative to the direction of rotation (e.g., creating a fan-shaped spray pattern approaching 90°). Curved section As the height decreases (toward the front of the deflector), the liquid flow is deflected at a smaller angle relative to the direction of rotation (e.g., resulting in a fan-shaped spray pattern approaching 10°). Between the front and rear of the deflector 38, the fan-shaped spray pattern can be between 10° and 90° depending on the particular area where the liquid flow strikes the deflector 38.

[0039] As noted above, the maximum pushing force (and therefore the maximum rotational speed) occurs when the liquid flow strikes the front of deflector 38. The minimum pushing force (and therefore the minimum rotational speed) occurs when the liquid flow strikes the rear of deflector 38. Between these two extremes, the pushing force varies with the angle of deflector 38 relative to arm portion 32a.

[0040] During operation, liquid ejected from nozzle 28 strikes deflector 38, creating a force that tends to pivot deflector 38 toward first arm portion 32a. At this point, maximum pushing force occurs, and arm 32 begins to accelerate about axis 14a. As rotational speed increases, centrifugal force then counteracts the force created by the liquid flow, causing deflector 38 to pivot away from first arm portion 34a. Arm 32 will settle at a speed where these two forces balance out.

[0041] The actual rotational speed of the arm 32 is determined by the pressure of the liquid stream ejected from the nozzle 28, the length of the arm portions 34a, 34b, the shape of the curved portion 38a and chamfered portion 38b, the weight of the deflector 38, and the pivot point 40 of the deflector 38. Therefore, a desired speed can be achieved by adjusting any of these parameters. However, in practice, the length of the arm is determined by the area to be cleaned, and the pressure is typically set to a predetermined level that provides the best cleaning effect. Therefore, varying these parameters may not be practical for achieving a desired rotational speed of the arm 32. Instead, changing the shape of the curved portion 38a and chamfered portion 38b, changing the pivot point 40 of the deflector 38, and / or changing the weight of the deflector 38 may be more practical for achieving a desired rotational speed of the spray arm 32.

[0042] In practice, a single deflector 38 located at one end of the arm 32 is sufficient to adjust the rotational speed of the spray arm 32. However, it is also possible to provide a deflector at each end of the spray arm. For example, a second nozzle can be located on the second arm portion. The second deflector is then pivotally connected to the second arm portion to receive the liquid stream emitted from the second nozzle.

[0043] Referring now to FIG. 7, a flowchart 50 is shown depicting steps of an exemplary method for adjusting the rotational speed of a spray arm 30 about an axis in accordance with the present invention. Variations of the illustrated method are possible. Thus, the illustrated embodiment should not be considered the only manner of practicing the invention disclosed herein. Also, while FIG. 7 shows a particular order of execution of the functional logic blocks, the order of execution of the blocks may be varied from the order shown. In addition, two or more blocks shown in succession may be executed concurrently or with partial concurrent execution. Also, some blocks may be omitted.

[0044] Beginning at block 52, pressurized liquid is sprayed from nozzle 28 located at end 36 of spray arm 30. The pressurized liquid is deflected by deflector 38. Curved section 38a with a first force that tends to pivot deflector 38 toward arm 30. If the first force is strong enough, deflector 38 will pivot so that the deflector is immediately adjacent to first arm portion 32a.

[0045] As the liquid exits the nozzle 28 and is deflected by the deflector 38, a second force is generated, as indicated by block 54. This second force pushes (rotates) the distal end 36 of the spray arm 30 about the axis 14a. If we consider the liquid to be ejected from the nozzle 28 at a fixed pressure, the magnitude of the second force is then determined by the location of the impingement on the deflector 38. As noted above, the location of the impingement can vary depending on the position of the deflector 38 relative to its pivot point 40. In this regard, the second "pushing force" is greatest when the deflector is pivoted toward the spray arm 30 and least when the deflector 38 is pivoted away from the spray arm 30. This change in second force is determined by the amount of force exerted on the distal end 36 of the spray arm 30 as the liquid exits the nozzle 28. Curved section The angle is determined by the deflection angle at 38a, which is smallest when deflector 38 pivots towards spray arm 30 and 30 It is greatest when turning away from

[0046] When the spray arm 30 is initially stationary, there is no force acting in a direction opposite to the first force, so the deflector 38 pivots toward the spray arm 30. The second "pushing" force then reaches a maximum. This second pushing force causes an angular acceleration of the spray arm 30 about the axis 14a, as indicated by block 56.

[0047] As the spray arm accelerates about axis 14a, a third (centrifugal) force begins to act on deflector 38 in a direction opposite to the first force, as indicated by block 58. As the rotational speed increases, the third force also increases, and the deflector begins to move away from spray arm 30. Thus, the second "pushing" force decreases, as indicated by block 60. The rotational speed of spray arm 30 stabilizes when the first and third forces balance (are in equilibrium). The point of equilibrium is the point at which a constant second (pushing) force is applied to spray arm 30 rotating at a predetermined, steady speed, as indicated by block 60.

[0048] Thus, the apparatus and method of the present invention can precisely adjust the rotational speed of the spray arm independent of friction at the center pivot and manufacturing tolerances, as well as the orientation of the spray nozzle on the spray arm.

[0049] While the present invention has been shown and described with respect to several embodiments or embodiments, equivalent alterations and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. In particular, with respect to the various functions performed by the above-described elements (components, assemblies, devices, compositions, etc.), the terms used to describe such elements (including references to "means") are intended, unless otherwise indicated, to correspond to any element that performs the specified function of the described element (i.e., is functionally equivalent), even if it is not structurally equivalent to a disclosed structure that performs that function in the presently illustrated embodiment or embodiments of the invention. In addition, while a particular feature of the invention may be described above with respect to only one or more of the embodiments, such feature may be combined with one or more other features of other embodiments as desired or advantageous for any or a particular application.

Claims

1. 1. A method for adjusting the speed of a spray arm rotatable about an axis, comprising: the spray arm comprises I) at least one nozzle; and II) at least one deflector pivotally mounted to the spray arm, the at least one deflector including a first surface proximal to the at least one nozzle with a curved portion and a second surface distal to the at least one nozzle with a chamfered portion, the chamfered portion and the curved portion having a shape that defines an angle at which a fluid flow is dispersed relative to a direction of rotation of the arm, the at least one nozzle being positioned toward the curved portion; A fluid is ejected from the at least one nozzle and directed toward the curved portion, i) a first force that pivots the at least one deflector toward the spray arm; ii) a second force that rotates the spray arm about the axis; This causes rotation of the spray arm about the axis generates a third force that pivots the at least one deflector away from the spray arm; The method wherein the first force and the third force balance at a predetermined rotational speed.

2. 2. The method of claim 1, further comprising selecting at least one of a weight of the at least one deflector or a position of a pivot of the at least one deflector to achieve the predetermined rotational speed.

3. The method of claim 1 or claim 2, further comprising the step of defining a shape of the curved portion to achieve the predetermined rotational speed.

4. The method of claim 1 , wherein the third force is a centrifugal force.

5. The method of claim 1 , wherein fluid impinging on the curved portion of the first surface forms a fan-shaped spray pattern.

6. 6. The method of claim 5, wherein the fan-shaped spray pattern is between 10° and 90°.

7. 7. The method of claim 1, wherein the second force increases as the deflector pivots toward the spray arm.

8. 8. The method of any one of claims 1 to 7, wherein the second force decreases as the deflector pivots away from the spray arm.

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