Spraying Arm Speed Regulator

Abstract

The rotational speed of the spray arm is adjusted according to centrifugal force and liquid jets to form a corner nozzle with a variable angle. The regulator includes a counterweight on a pivot and a fluid nozzle. The counterweight has a curved surface to produce a corner nozzle with a variable angle according to the counterweight angle. The centrifugal force generated during rotation pushes the counterweight outwards and increases as the rotational speed of the spray arm increases. The liquid jets are located outside the pivot point and tend to push the counterweight inwards. The thrust of the liquid jets is maximum when the counterweight is most inwards and minimum when the counterweight is most outwards. The regulator stabilizes the arm speed at a specific speed, independent of the friction of the central pivot and the direction tolerance of the nozzle arms of the nozzles. The speed is stabilized when the centrifugal force on the counterweight is equal to the thrust of the liquid jets.

Description

Technical Field

[0001] The present invention relates to a spray arm of a cleaning machine for cleaning medical, pharmaceutical and / or laboratory utensils, and more particularly to regulating the rotational speed of the spray arm. Background Art

[0002] Cleaning machines, such as dishwashers or machines for cleaning and disinfecting medical, pharmaceutical and / or laboratory utensils, include a spray chamber into which a trolley for holding objects to be cleaned can be introduced. One or more spray arms spray liquid, such as water or other cleaning liquid, upwardly and / or downwardly through high-pressure spray holes to rinse and clean the utensils in the spray chamber.

[0003] Typically, the spray chamber has a non-circular shape factor, such as rectangular, while the spray arm sprays in a circular pattern. As a result of spraying in a circular pattern, the corner portions of the spray chamber may not receive sufficient (or any) cleaning liquid, and thus the utensils placed in this part of the spray chamber may not be cleaned adequately. To address this issue, additional nozzles are placed at the ends of the spray arm and angled towards the corner portions. For example, the nozzles at one end can be tilted slightly upward and the nozzles at the other end can be tilted slightly downward. For low-pressure / high-flow systems, simple nozzles can be provided on the side of the spray arm near the nozzles. For high-pressure systems, it is preferable to use angled nozzles to minimize the flow rate.

[0004] Due to the different spraying directions of the liquid cleaner, the forces generated by these corner nozzles cause the spray arm to rotate. To provide effective cleaning, it is preferable to spray the cleaning liquid at high pressure and at a prescribed speed. However, this high pressure often causes the rotational speed of the spray arm to be too high, which requires a method for regulating the rotational speed of the spray arm.

[0005] Typically, the rotational speed of the spray arm is set by selecting a specific angle and pressure at which the corner nozzles emit the liquid cleaner. For example, a trial-and-error process can be performed in which the tilt angle of the corner nozzles is adjusted until the speed is within the desired range. However, this process is very time-consuming and it is difficult to achieve precise results, especially for long spray arms that require a lower rotational speed. In addition, due to manufacturing tolerances, it is difficult to achieve low-speed rotation using fixed / adjustable corner nozzles. Summary of the Invention

[0006] The device and method according to the present invention can precisely adjust the rotational speed of the spraying arm. The spraying arm speed regulator according to the present invention uses centrifugal force and liquid spraying to create a corner nozzle with a variable angle to adjust the rotational speed of the spraying arm. The regulator includes a counterweight located on a pivot with a water jet, and the counterweight has a curved surface. According to the angle of the counterweight relative to the nozzle, a corner nozzle with a variable angle can be generated. The centrifugal force generated during rotation pushes the counterweight outward and increases as the rotational speed of the spraying arm increases. The water jet is located outside the pivot point and tends to push the counterweight inward. The thrust of the water jet is the largest when the counterweight is the most inward and the smallest when the counterweight is the most outward. When the centrifugal force on the counterweight is equal to the thrust of the water jet, the speed is stable. The regulator according to the present invention stabilizes the arm speed at a specific speed, independent of the central pivot friction and the direction tolerance of the nozzle of the nozzle arm.

[0007] According to one aspect of the present invention, a device for a cleaning machine includes: an arm rotatable about an axis, the arm including a first arm portion and a second arm portion exactly opposite to the first arm portion; a first nozzle provided on the first arm portion; a first deflector pivotally connected to the first arm portion and arranged to receive a fluid stream emitted from the first nozzle; wherein the fluid emitted from the first nozzle impinges on the first deflector and generates a force tending to rotate the first deflector towards the first arm portion to rotate the arm, and the rotation of the arm about the axis generates a force tending to move the first deflector away from the first arm portion.

[0008] In one embodiment, the device includes a base, wherein the arm is rotatably connected to the base about an axis.

[0009] In one embodiment, the pivot point of the first deflector is located radially inward relative to the first nozzle.

[0010] In one embodiment, the first deflector includes a proximal surface having a curved portion, and the proximal surface is arranged near the first nozzle.

[0011] In one embodiment, the curved portion generates a fan-shaped spraying pattern between 10 degrees and 90 degrees.

[0012] In one embodiment, when the first deflector rotates towards the first arm portion, the fluid thrust emitted from the first nozzle increases.

[0013] In one embodiment, when the first deflector rotates away from the first arm portion, the fluid thrust emitted from the first nozzle decreases.

[0014] In one embodiment, the first deflector includes a distal surface having a chamfer.

[0015] In one embodiment, the fluid emitted by the first nozzle generates a force that causes the arm to rotate about an axis, and this force varies based on the distance of the first deflector relative to the first arm portion.

[0016] In one embodiment, the first nozzle is disposed at the outer end of the first arm portion.

[0017] In one embodiment, the device includes: a second nozzle disposed on the second arm portion; and a second deflector pivotally connected to the second arm portion and arranged to receive a fluid flow emitted from the second nozzle.

[0018] According to another aspect of the present invention, a method for adjusting the speed of a spraying arm about an axis is provided, wherein the spraying arm includes at least one deflector pivotally connected to the spraying arm and having a curved surface, and at least one nozzle disposed relative to the curved surface. The method includes: emitting fluid from at least one nozzle to impinge on the curved surface and causing i) a first force tending to rotate at least one deflector towards the spraying arm, and ii) a second force tending to rotate the spraying arm about the axis, wherein the rotation of the spraying arm about the axis generates a third force that tends to move at least one deflector away from the spraying arm, thereby achieving a balance between the first force and the third force at a predetermined rotational speed.

[0019] In one embodiment, the method includes selecting at least one of the counterweight of at least one deflector or the pivot position of at least one deflector to achieve a predetermined speed.

[0020] In one embodiment, the method includes defining the shape of the curved surface to achieve a predetermined speed.

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

[0022] In one embodiment, the fluid impinging on the surface forms a fan-shaped spraying pattern.

[0023] In one embodiment, the fan-shaped spraying pattern is between 10 degrees and 90 degrees.

[0024] In one embodiment, the second force increases as the deflector rotates towards the spraying arm.

[0025] In one embodiment, the second force decreases as the deflector pivots away from the spraying arm.

[0026] The following description and the drawings set forth in detail certain illustrative embodiments of the invention. However, these embodiments merely indicate some of the various ways in which the principles of the invention may be employed. When considered in conjunction with the drawings, other objects, advantages, and novel features of the invention will become apparent from the following detailed description of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention may take physical form in certain components and component arrangements, and its preferred embodiments will be described in detail in the specification and illustrated in the drawings forming a part of the present invention, wherein:

[0028] Figure 1 is a side view of an exemplary cleaning machine to which the principles of the present invention may be applied;

[0029] Figure 2 is a perspective view of an exemplary spraying arm according to the present invention;

[0030] Figure 3 is a perspective view of an exemplary deflector for adjusting the speed of the spraying arm according to the present invention, wherein the deflector pivots away from the spraying arm;

[0031] Figure 4 is a perspective view of an exemplary deflector for adjusting the speed of the spraying arm according to the present invention, wherein the deflector rotates towards the spraying arm;

[0032] Figure 5 is a top view of an exemplary deflector for adjusting the speed of the spraying arm according to the present invention, wherein the deflector pivots away from the spraying arm;

[0033] Figure 6 is a top view of an exemplary deflector for adjusting the speed of the spraying arm according to the present invention, wherein the deflector rotates towards the spraying arm; and

[0034] Figure 7 is a flow chart illustrating an exemplary procedure for adjusting the speed of the spraying arm according to the present invention. DETAILED DESCRIPTION

[0035] Embodiments of the present invention will now be described with reference to the drawings, wherein like reference numerals are always used to denote like elements. It is understood that these drawings are not necessarily to scale. Further, the present invention has found utility in cleaning machines that perform cleaning operations using liquids, and thus, the present invention will be mainly described herein. However, the principles of the present invention may be applied to other types of devices and / or where a fluid (such as compressed air, etc.) may be used instead of a liquid as the main medium.

[0036] Referring to FIG. 1, a cleaning machine 10 (such as a dishwasher or a machine for cleaning and disinfecting medical, pharmaceutical, and / or laboratory utensils) generally has a spraying chamber 12 for cleaning utensils. The spraying chamber 12 includes at least one rotating spraying arm 14. The spraying arm 14 rotates about a vertical axis 14a to supply a liquid medium to the utensils placed in the cleaning chamber 12, and the liquid medium is supplied under pressure through a pump assembly 16 and associated flow channels 18. A removable bin 20 for storing utensils to be cleaned is arranged in the spraying chamber 12 and is sprayed with the cleaning liquid discharged from the spraying arm 14.

[0037] The spray arm 14 is supported on a base 26 mounted on the floor of the spray chamber 12, and the spray arm 14 sprays the cleaning liquid upwardly onto the appliance. Additionally, another spray arm 14 can be suspended from an overhead bracket 26a and spray the cleaning liquid downwardly onto the appliance.

[0038] Each spray arm 14 includes an outlet nozzle 28 for generating a spray liquid that sprays in a predetermined spray direction, which is generally at an angle greater than 0 degrees and less than 90 degrees with respect to the direction of rotation of the spray arm. The force of the properly aimed jet of the liquid medium flowing out of the spray arm 14 drives the spray arm 14 to rotate about its axis of rotation 14a. More details about the cleaning machine 10 can be found in U.S. Patent No. 7,841,104, which is incorporated herein by reference in its entirety.

[0039] As will be appreciated, the arrangement of the cleaning machine 10 and the spray arm 14 can take various forms, and the above-described embodiments are merely examples of several ways in which the cleaning machine can be configured. For example, the cleaning machine can include a spray arm mounted on a movable cart. In other embodiments, an open configuration (e.g., without walls) can be implemented instead of the spray chamber 12. Such an "open" embodiment may be practical in an industrial environment for cleaning large objects.

[0040] Generally, the rotational speed of the spray arm 14 is set by selecting the specific angle and pressure at which the corner nozzles emit the liquid. Partly due to manufacturing tolerances, this process does not produce consistent results. Additionally, the process is very time-consuming, and it is difficult to obtain precise results as the length of the spray arm increases.

[0041] According to the present invention, a rotatably mounted liquid flow deflector is used to adjust the rotational speed of the spray arm, and the liquid flow deflector has a curved surface with a fixed radius. As described in more detail below, depending on the pivot position of the deflector relative to the liquid nozzle, the liquid flow emitted from the nozzle is deflected at different angles with respect to the direction of rotation of the spray arm. Since the angle of the liquid stream can be changed relative to the direction of rotation of the arm, the "thrust" generated by the stream (rotating arm) can be changed. In this regard, the curved surface is constructed such that when the deflector rotates towards the arm, the thrust generated by the liquid emitted from the nozzle and impinging on the curved surface increases. Conversely, when the deflector rotates away from the arm, the thrust of the liquid discharged from the nozzle and impinging on the curved surface decreases. As discussed in more detail below, the liquid stream impinging on the deflector tends to turn the deflector towards the arm (generating the maximum "thrust"), and, as the arm rotates, the centrifugal force tends to pivot the deflector away from the arm (decreasing the "thrust"). These two forces reach an equilibrium at a predetermined rotational speed.

[0042] For example, when the spray arm is initially in the stopped position, liquid is discharged from a nozzle located at the end of the spray arm at a predetermined pressure. The liquid impinges on the curved surface of the deflector with a first force, causing the deflector to rotate towards the spray arm. At the same time, the discharged liquid is deflected by an angle with respect to the rotational direction of the arm, thereby generating a second "thrust". When the deflector rotates towards the arm, the thrust reaches a maximum, causing the arm to accelerate. As the speed of the arm increases, the centrifugal force causes the deflector to rotate away from the spray arm, and the centrifugal force depends on the weight of the deflector and the rotational speed of the arm. As the deflector rotates away from the arm, the angle of the flow with respect to the rotational direction changes, and the second "thrust" decreases. When the first force and the third force reach an equilibrium point, the rotational speed of the arm will stabilize.

[0043] Referring now to FIG. 2, shown is an exemplary spray arm 30 according to the present invention, which is in an "open" configuration (i.e., not in the spray chamber shown in FIG. 1). The spray arm 30 rotatable about axis 14a is connected to a bracket 31 and includes a base 32 rotatable relative to the bracket 31, a first arm portion 34a connected to the base 32, and a second arm portion 34b connected to the base, the second arm portion 34b being exactly opposite to the first arm portion 34a. Also referring to FIGS. 3-6, a first nozzle 28 is disposed at the distal end 36 of the first arm portion 32a, and 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 radially inward with respect to the nozzle 28, i.e., 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 located near the nozzle 28 to receive the liquid flow discharged from the nozzle 28.

[0044] As described herein, the deflector 38 includes a curved surface 38a, as shown in FIGS. 5 and 6. In addition, the surface of the deflector 38 remote from the nozzle 28 includes a chamfered portion 38b, where the chamfered portion causes the height of the curved surface 38a to be lowest at the front of the deflector 38 and to increase moving towards the rear of the deflector. In the illustrated embodiment, the chamfered portion 38b stops approximately halfway towards the rear of the deflector 38. However, the chamfered portion may stop at different positions along the deflector 38 and may also extend completely to the rear of the deflector 38.

[0045] The radius of the curved surface 38a and the chamfered portion 38b define the angle at which the liquid flow disperses relative to the direction of rotation. In this regard, since the chamfered portion 38b is thickest, the height of the curved portion is at its highest point (in the mid-rear of the deflector 38), causing the liquid flow to deflect at a greater angle relative to the direction of rotation (e.g., producing a fan spray pattern approaching 90 degrees). When the thickness of the chamfered portion 38b decreases and the height of the curved portion decreases (towards the front of the deflector), the liquid flow deflects at a smaller angle relative to the direction of rotation (e.g., producing a fan spray pattern approaching 10 degrees). Between the front and rear of the deflector 38, the fan spray pattern can be between 10 degrees and 90 degrees, depending on the specific area of the deflector 38 where the liquid flow impinges.

[0046] Accordingly, when the liquid flow impinges on the front of the deflector 38, maximum thrust (and thus maximum rotational speed) is achieved, and when the liquid flow impinges on the rear of the deflector 38, minimum thrust (and thus minimum rotational speed) is achieved. Between these two extremes, the thrust varies with the angle of the deflector 38 relative to the arm portion 32a.

[0047] In operation, the liquid discharged from the nozzle 28 impinges on the deflector 38 and generates a force that tends to rotate the deflector 38 towards the first arm portion 32a. At this position, maximum thrust is generated and the arm 32 begins to accelerate about the axis 14a. As the rotational speed increases, the centrifugal force then counteracts the force generated by the liquid flow and tends to move the deflector 38 away from the first arm portion 34a. The arm 32 will settle at a speed where the two forces are balanced.

[0048] The actual rotational speed of the arm 32 is determined by the pressure of the liquid flow discharged from the nozzle 28, the lengths of the arm portions 34a, 34b, the shape of the curved portion 38a and the chamfered portion 38b, the weight of the deflector 38, and the pivot point 40 of the deflector 38. Thus, any of these parameters can be adjusted to achieve the desired speed. However, in practice, the arm length is determined by the area to be cleaned, and the pressure is typically set to a predetermined level that provides optimal cleaning. Therefore, it may not make sense to change these parameters to achieve the desired rotational speed of the arm 32. Instead, changing the shape of the curved portion 38a and the chamfered portion 38b, changing the pivot point 40 of the deflector 38, and / or changing the weight of the deflector 38 is more practical in achieving the desired rotational speed of the spray arm 32.

[0049] In fact, a single deflector 38 arranged at one end of the arm 32 is sufficient to adjust the rotational speed of the spray arm 32. However, deflectors can be installed at each end of the spray arm. For example, a second nozzle can be arranged on the second arm portion, and a second deflector can be pivotally connected to the second arm portion to receive the liquid flow emitted from the second nozzle.

[0050] Referring now to FIG. 7, shown is flowchart 50 which depicts steps of an exemplary method for adjusting the speed of the spray arm 30 about an axis in accordance with the present invention. Variations to the illustrated method are possible and, accordingly, the illustrated embodiments should not be regarded as the only way to implement the techniques disclosed herein. Further, although FIG. 7 shows a particular order of performing functional logic blocks, the order of performing the blocks may vary with respect to that shown. Additionally, two or more blocks shown in succession may be executed in parallel or partially in parallel. Some blocks may also be omitted.

[0051] Starting at block 52, pressurized liquid is discharged from nozzle 28 located at the distal end 36 of spray arm 30. The pressurized liquid impacts the curved surface 38a of deflector 38 with a first force that tends to rotate deflector 38 toward arm 30. If the first force is strong enough, deflector 38 will rotate such that the deflector is adjacent to the first arm portion 32a.

[0052] When the liquid is discharged from nozzle 28 and deflected by deflector 38, a second force is generated, as shown at block 54. This second force tends to push (rotate) the distal end 36 of spray arm 30 about axis 14a. Assuming the liquid is discharged from nozzle 28 at a fixed pressure, the magnitude of the second force depends on the location of the impact on surface 38. As described above, the impact location may vary depending on the position of deflector 38 about its pivot point 40. In this regard, the second “thrust” force is maximum when the deflector rotates toward the spray arm and minimum when deflector 38 rotates away from spray arm 30. The difference in the second force is due to the angle at which the ejected liquid deviates from surface 38a, which is minimum when deflector 38 rotates toward spray arm 30 and maximum when deflector 38 rotates away from spray arm 38.

[0053] When spray arm 30 is initially stationary, there is no force to counteract the first force and, thus, deflector 38 will rotate toward spray arm 30 and, thus, the second “push” force will be at a maximum. As shown at block 56, the second thrust force will cause an angular acceleration of spray arm 30 about axis 14a.

[0054] As 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 shown at block 58. As the rotational speed increases, the third force also increases, causing the deflector to begin rotating away from spray arm 30, thereby reducing the second “push” force, as shown at block 60. Once the first and third forces reach an equilibrium point (balance), the rotational speed of spray arm 30 will stabilize at which point a constant second (push) force is applied to spray arm 30 at a steady, predetermined speed, as shown at block 60.

[0055] Accordingly, the apparatus and method in accordance with the present invention can precisely adjust the rotational speed of the spray arm, independent of center pivot friction and manufacturing tolerances, such as nozzle orientation on the spray arm.

[0056] Although the present invention has been shown and described with respect to one or more embodiments, equivalent changes and modifications may be made by others skilled in the art upon reading and understanding this specification and the drawings. In particular, with respect to the various functions performed by the above-described elements (components, assemblies, devices, compositions, etc.), unless otherwise specified, the terms used to describe these elements (including references to "means") are intended to correspond to any element that performs the specified function of the element (i.e., functionally equivalent), even if not structurally equivalent to the disclosed structure that performs the function in one or more exemplary embodiments of the present invention. Further, although a particular feature of the present invention may have been described above only with respect to one or more of the embodiments, this feature may be combined with one or more other features of the other embodiments, which may be desirable and advantageous for any given or particular application.

Claims

1. A device for a cleaning machine, which comprises: an arm rotatable about an axis, the arm including a first arm portion and a second arm portion completely opposite to the first arm portion; a first nozzle disposed on the first arm portion; a first deflector pivotally connected to the first arm portion and arranged to receive a fluid stream emitted from the first nozzle; and wherein the fluid discharged from the first nozzle impinges on the first deflector and generates a force tending to rotate the first deflector towards the first arm portion to rotate the arm, and the rotation of the arm about the axis generates a force tending to move the first deflector away from the first arm portion, and wherein the first deflector includes a proximal surface having a curved portion and a distal surface having a chamfered portion, the curved portion for receiving the fluid stream ejected from the first nozzle, wherein the radius of the curved portion and the chamfered portion determine the angle at which the fluid stream is dispersed relative to the rotation direction of the arm.

2. The device according to claim 1, further comprising a base, wherein the arm is rotatably connected to the base about the axis.

3. The device according to claim 1, wherein the pivot point of the first deflector is radially inward relative to the first nozzle.

4. The device according to claim 1, wherein the proximal surface having the curved portion is disposed near the first nozzle.

5. The device according to claim 4, wherein the curved portion generates a fan-shaped spraying pattern between 10 degrees and 90 degrees.

6. The device according to claim 1, wherein, when the first deflector rotates towards the first arm portion, the thrust of the fluid emitted from the first nozzle increases.

7. The device according to claim 1, wherein, when the first deflector rotates away from the first arm portion, the thrust of the fluid emitted from the first nozzle decreases.

8. The device according to claim 1, wherein the fluid discharged from the first nozzle generates a force that rotates the arm about the axis, and the force varies according to the distance of the first deflector relative to the first arm portion.

9. The device according to claim 1, wherein the first nozzle is disposed at the outer end of the first arm portion.

10. The device according to claim 1, further comprises: a second nozzle disposed on the second arm portion; and a second deflector pivotally connected to the second arm portion and arranged to receive a fluid stream emitted from the second nozzle.

11. A method for adjusting the speed of a spraying arm about an axis, wherein the spraying arm includes a first arm portion and a second arm portion completely opposite to the first arm portion, and at least one deflector pivotally connected to the spraying arm, the deflector including a proximal surface having a curved portion and a distal surface having a chamfered portion, and the spraying arm further includes at least one nozzle disposed relative to the curved portion, and the chamfered portion and the radius of the curved portion determine the angle at which the fluid stream is dispersed relative to the rotation direction of the spraying arm, the method comprises: spraying fluid from at least one nozzle to impinge on the curved portion and generate i) a first force tending to rotate at least one deflector towards the spraying arm, and ii) a second force tending to rotate the spraying arm about the axis, Wherein, the spraying arm rotates around the axis to generate a third force, and the third force tends to move at least one deflector away from the spraying arm. Thus, a balance between the first force and the third force is achieved at a predetermined rotational speed.

12. The method according to claim 11, further comprising selecting at least one of the weight of at least one deflector or the pivot position of at least one deflector to achieve a predetermined speed.

13. The method according to claim 11, further comprising defining the shape of the curved portion to achieve a predetermined speed.

14. The method according to claim 11, wherein the third force is a centrifugal force.

15. The method according to claim 11, wherein the fluid impacts the proximal surface of the curved portion to form a fan-shaped spraying pattern.

16. The method according to claim 15, wherein the fan-shaped spraying pattern is between 10 degrees and 90 degrees.

17. The method according to claim 11, wherein the second force increases as the deflector rotates towards the spraying arm.

18. The method according to claim 11, wherein the second force decreases as the deflector pivots away from the spraying arm.

Images