ROTARY VALVE INTENDED FOR USE WITH A FLUID DOSING UNIT

Abstract

ROTARY VALVE FOR USE WITH A FLUID DOSING UNIT The invention relates to a rotary valve (10) pivoted by an arm (46) connected to a piston (34) which is driven by a pressurized fluid; either water or air. The orientation of the valve body (14) within the valve housing (12) directs the fluid in one of two directions to move the piston (34). The arm (46) of the rotary valve is connected to a cam (56) which rotates a shaft (20) connected to the valve body (14). Two cam rollers are driven toward the outer surface of the rotary cam member. The cam rollers provide force to the cam (56) to assist in changing the orientation of the valve body (14). There are two recesses on the cam which are correlated to the end of the movement of the piston (34) such that the rotary valve (10) does not stop at an end point of the stroke of the piston (34).The rotary valve (10) can be used in a chemical dosing or chemical application device that is operated by a pressurized fluid. Fig. 1.

Description

Title of the invention: ROTARY VALVE FOR USE WITH A FLUID METERING DEVICE FIELD OF THE INVENTION

[0001] The present invention relates to a rotary valve suitable for use with a fluid metering device.

[0002] CONTEXT OF THE INVENTION

[0003] The present invention relates generally to the mixing of fluids. More specifically, the invention relates to the continuous mixing of two fluids in a regular proportion into an output stream.

[0004] Proportional mixing of fluids by self-driven automatic devices is known. Such a device can be used to mix a fluid stream, such as water or air, with another fluid such as drugs, vaccines, nutrients, treatment agents or the like. Traditional self-driven dosers have a fluid motor and a servo pump.

[0005] In a traditional self-driven device, the pressure of a first fluid stream, such as water, is used to actuate the device. The first fluid stream moves a piston inside a cylinder, automatically metering a quantity of the first fluid with each stroke, filling the cylinder with fluid. A valve alternates the intake of fluid from one side of the piston to the other. The fluid pressure at the intake moves the driving piston, while fluid on the opposite side of the piston is simultaneously expelled. In one complete stroke of the cylinder, two cylinder capacities of the first fluid are expelled from the cylinder into the output stream.

[0006] In known devices, the piston also drives a metering device. The metering device may comprise a second pump having a second piston and a second cylinder. The second piston has a single working face, compared to the main piston which has two. The second pump draws in a quantity of a second fluid through an inlet and then expels it through an outlet into the outlet stream. The expelled second fluid mixes with the first fluid expelled from the main piston. In one stroke, a displacement of fluid from the second cylinder is expelled into the outlet stream. Thus, constant proportions of the two fluids are mixed during each stroke of the main piston.

[0007] Conventional devices often use a rotary valve as the valve. However, instead of pivoting fully about an axis, the rotary valve pivots one full rotation less a certain distance, stops and reverses direction, and then pivots back in the opposite direction. In other words, the rotary valve does not perform not continuously complete rotations. Such movement is often controlled using a reversing switch or biased linkage. When the rotary valve reaches the end of rotation, the reversing switch or biased linkage provides a force to reverse the direction of rotation.

[0008] While likely effective for its intended uses, this type of movement and structure creates noticeable noise as the diverter or biased linkage moves back and forth to constantly change the direction of the rotary valve. While the noise is potentially unacceptable in many environments, it is symptomatic of an inherent volumetric limitation in the design. As the required volume of the drive fluid increases, the size of the ports, valve, and diverter or biased linkage and stopper increases proportionally.

[0009] The increased inertial mass of the reverser or stressed linkage results in greater shock transmission to the internal and external components, resulting in higher maintenance and replacement of stops, internal bearings, and other parts necessary to control the movement. The ever-increasing size, strength, and pull of the reversing spring disrupts the vertical orientation of the valve and further accelerates damage to the internal bearings.

[0010] Therefore, it would be desirable to provide a device that addresses one or more of these concerns. Summary of the invention

[0011] A new rotary valve has been invented which may be used in a pressurized water-operated chemical metering device such as that described in U.S. Patent No. U.S. 6,485,272. The rotary valve is rotated by an arm connected to a piston which is actuated by the pressurized water. Orientation of the valve body (in the valve housing) directs the water in one of two directions to move the piston. The rotary valve arm is connected to a cam which pivots a shaft connected to the valve body. Cam followers are biased toward the outer surface of the rotary cam member to provide a force to the cam to assist in changing the orientation of the valve body. Indentations or notches on the cam are correlated to the end of the piston movement so that the rotary valve does not stop at an end point of the piston stroke.

[0012] Unlike conventional rotary valves, the present rotary valve pivots entirely about its axis and performs continuous rotations. There is therefore no need for a reversing switch or other device to force the rotary valve to change direction. Compared with conventional designs, destructive shock transmission and noise are significantly reduced or eliminated by the present rotary valve, and there are fewer parts that are more easily subject to wear and tear.

[0013] Accordingly, in one aspect of the present invention, the present invention may be generally characterized as describing a rotary valve for use with a fluid metering device, the rotary valve comprising: a valve housing having an inlet and an outlet; a valve body rotatably mounted with the valve housing; a piston configured to move linearly within a cylinder; and an arm configured to transfer linear motion of the piston into rotational motion of the valve body and rotate the valve body 360 degrees within the valve housing.

[0014] In another aspect, the present invention may be characterized, generally, as describing a rotary valve for use with a fluid metering device, the rotary valve comprising: a valve housing having an inlet and an outlet; a valve body rotatably mounted with the valve housing; a piston configured to move linearly within a cylinder; a cam disposed externally of the valve housing, the cam being secured to the valve body so as to impart rotational motion to the valve body; and, an arm secured to the piston and the cam and configured to transfer linear motion of the piston into rotational motion of the valve body such that the valve body pivots entirely within the valve housing.

[0015] These and other aspects and embodiments of the present invention, which may be combined in any conceivable combination, will be apparent to those of ordinary skill in the art based on the following description of the drawings and the detailed description of the preferred embodiments.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The attached drawings will make it possible to understand how the invention can be produced and practiced, among which:

[0018] [Fig.l] is a sectional side view of a rotary valve according to the present invention with a valve body in a first orientation;

[0019] [Fig.2] is a sectional side view of the rotary valve shown in [Fig.l], wherein the valve body is in a second orientation;

[0020] [Fig.3] is a top view of a rotary valve according to the present invention;

[0021] [Fig.4] is a top view of a cam and a cam follower according to one or several aspects of the present invention; and

[0022] [Fig.5] is a partial sectional side view of a valve body having bearing assemblies according to one or more embodiments of the present invention. DETAILED DESCRIPTION

[0023] As mentioned above, a new rotary valve has been invented, which constitutes a valve that pivots fully to change a fluid flow actuating the rotary valve.

[0024] Accordingly, with reference to the accompanying drawings, one or more embodiments of the present invention will now be described, it being understood that the described embodiments are merely preferred and are not intended to be limiting.

[0025] Referring to Figs. 1 and 2, a rotary valve 10 according to the present invention will be described. Although described as being for use with a fluid metering device, it is understood that the rotary valve 10 may be used in other devices.

[0026] The rotary valve 10 includes a valve housing 12 with a valve body 14 disposed within the valve housing 12. The valve housing 12 includes an inlet 16 for a fluid, such as water or air, which will be used to actuate the device associated with the rotary valve 10. Preferably located on an opposite side of the valve housing 12 is an outlet 18 for the expelled fluid. The valve body 14 includes a shaft 20 that allows the valve body 14 to pivot and change the orientation of the valve body 14.

[0027] Inside the valve housing 12 is an upper chamber 22 which is in communication with the inlet 16 and configured to receive the fluid. A lower chamber 24 in the valve housing 12 is in communication with the outlet 18 and supplies fluid to the outlet 18. The lower chamber 24 is fluidically isolated (within the valve housing 12) from the upper chamber 22. A pair of upper flow conduits 26a, 26b are located on opposite sides of the valve housing 12 and are each in selective communication with the upper chamber 22. A pair of lower flow conduits 28a, 28b are also located on opposite sides of the valve housing 12 and are each in selective communication with the lower chamber 24. The pairs of upper and lower flow conduits 26a / 28a, 26b / 28b on each side are fluidically connected to a vertical flow conduit 30a, 30b.

[0028] Each vertical flow conduit 30a, 30b is in communication with one side of a cylinder 32 which contains a piston 34, which is configured to move in a linear direction (along its axis) within the cylinder 32. The cylinder 32 may be formed internally integral with the valve housing 12, or it may be fixed thereto. The piston 34 includes a piston head 36 and a piston shaft 38 which extends from the piston head 36 to the outside of the cylinder 32.

[0029] Within the valve housing 12 are multiple paths for the fluid as it moves from the inlet 16 to the outlet 18. The orientation of the valve body 14 directs the fluid toward one of the paths.

[0030] In particular, the valve body 14 includes an upper seal 40 and a lower seal 42 that overlap the valve block portion with minimum valve-to-case clearance in combination with maximum concentricity of the components. A minimum overlap of 1 / 8 inch, for each side, of the upper seal 40 and the lower seal 42 is necessary so that the seals 40, 42 are at least 1 / 4 inch wider than the flow conduits 26a, 26b, 28a, 28b.

[0031] The upper seal 40 is configured to prevent fluid from entering one of the upper flow conduits 26a, 26b from the upper chamber 22, while allowing fluid to flow from the upper chamber 22 into the other of the upper flow conduits 26a, 26b. The lower seal 42 is configured to prevent fluid from entering the lower chamber 24 from one of the lower flow conduits 28a, 28b, while allowing fluid to flow from the other of the lower flow conduits 28a, 28b into the lower chamber 24. The upper and lower seals 40, 42 are arranged to be on opposite sides of the valve body 14 such that, for example, when the upper left (as shown in the figures) flow conduit 26a is open, the lower right flow conduit 28b is open. Rotation of the shaft 20 of the valve body 14 changes the orientation of the valve body 14.

[0032] For example, starting in [Fig. 1], when fluid enters the upper chamber 22, it flows to the upper left flow conduit 26a. The upper seal 40 prevents the fluid from entering the upper right flow conduit 26b. From the upper left flow conduit 26a, the fluid flows into the left vertical conduit 30a, and down into the cylinder 32. The lower seal 42 prevents the fluid from flowing out of the lower left flow conduit 28a into the lower chamber 24.

[0033] Inside the cylinder 32, the fluid presses against the piston head 36 and forces the piston 34 to move to the right. Fluid present to the right of the piston head 36 (e.g., from a previous stroke) is forced out of the cylinder 32 as the piston head 36 moves to the right. The fluid exiting the cylinder 32 passes into the right vertical flow conduit 30b. The upper seal 40 prevents the fluid from flowing out of the upper right flow conduit 26b into the upper chamber 22. As a result, the fluid flows through the lower right flow conduit 28b, into the lower chamber 24, and out of the rotary valve through the outlet 18.

[0034] Eventually, the piston 34 reaches the end of its stroke, and the orientation of the valve body 14 changes to reverse the flow (as shown in [Fig.2]) such that the fluid moves the piston head 36 to the left. In order to change the orientation of the valve body 14, an arm 46 is put in place.

[0035] The arm 46 includes a lower portion 48 that includes a first end 50 attached to the piston shaft 38. A second end 52 of the lower portion 48 is attached to a second portion 54 of the arm 46. The second portion 54 of the arm 46 is attached to a cam 56. The cam 56 is attached to the shaft 20 of the valve body 14 such that as the cam 56 pivots, the valve body 14 pivots. In this manner, the arm 46 converts the linear motion of the piston 34 into a rotational motion of the valve body 14 within the valve housing 12 while changing orientation. Accordingly, the linear motion of the piston 34 pivots the valve body 14 between the orientations shown in Figs. 1 and 2 without reversal of direction and allowing the valve body 14 to pivot fully (i.e. 360 degrees) continuously around its axis of rotation (e.g. shaft 20).

[0036] As shown in [Fig. 3], in order to minimize the chances of the valve body 14 stopping in a position that is between the two orientations shown in Figs. 1 and 2, the cam 56 includes a cam surface 58 formed by an outer surface 60 of the cam 56. The cam surface 58 includes one or more notches 62, or indentations. These notches 62 are changes in the outer shape of the cam 56. Accordingly, in a top view (such as that shown in [Fig. 3]), the outer shape of the cam 56 is not a perfect circle. Instead, the cam 56 has two different radii R1, R2 that are connected by transition sections that correspond to the notches 62.

[0037] At least one cam follower 64 is provided and configured to interact with the cam surface 58. As shown in [Fig. 4], the cam follower 64 may include a roller 65 or a bearing within a housing 67. The roller 65 moves along the cam surface 58. The housing 67 may be grooved such that the cam is received within the housing 67. Preferably, at least two cam followers 64 are provided, the two followers 64 being located on opposite sides of the cam 56.

[0038] Each cam follower 64 is biased toward the cam 56, for example by a spring 68. The force of the spring 68 is directly related to the energy required to ensure that the valve body 14 does not stop moving when the piston 34 changes direction. In particular, the positioning of the notches 62 is based on the displacement of the piston 34 in its stroke, so that when the piston 34 reaches the end of the stroke, at least one cam follower 64 interacts with at least one notch 62. If fluid continues to be supplied to the rotary valve 10, the force of the fluid is sufficient to overcome the spring 68, and the cam 56, and therefore the valve body 14, continues to pivot. If, on the other hand, the fluid has stopped, the spring 68, depending on whether the transition takes place from RI to R2 or from R2 to RI, will either force the cam 56 to continue pivoting or stop the rotation. The cam follower 64 thus helps to ensure that the valve body continues to pivot or stops pivoting when fluid flow ceases to ensure that it does not become trapped between the two orientations. One or more brackets 71 may be attached to the valve 10 using assembly members 73 to hold the spring 68.

[0039] Turning to [Fig. 5], the valve body 14, and more specifically the shaft 20, may be surrounded by two bearing assemblies 80, one at each end within the valve housing 12. Each bearing assembly 80 includes one or more bearings 82, such as sleeve bearings, seated in a sealed protective housing 84. The sealed protective housings 84 prevent fluid contamination and the resulting reduction in operating life and premature failure of the bearings 82. Seals 86, which may be double-lip, low-friction seals, for example, QUAD-RING® seals, may be used between the bearing assemblies 80 and the valve housing 12.

[0040] With the rotary valve 10 according to the above, the valve body 14 can pivot continuously in one direction around its axis of rotation, avoiding the problems mentioned above.

[0041] Again, such a valve 10 is particularly desirable in a self-driven automatic fluid metering device. As can be appreciated, with such a device, the fluid from the outlet 18 may be mixed with a metered portion of a second fluid. The movement of the piston 34 may be used to also move the fluid therein, or the first fluid may be transferred to a second piston which operates in a similar manner to provide a metered amount of second fluid. Such a metering device is shown and described in U.S. Patent No. U.S. 6,485,272. However, the use of the rotary valve 10 in a fluid metering device is, again, merely preferred and is not intended to be limiting.

[0042] As will be apparent from the foregoing description, the invention is capable of being embodied with various adaptations and modifications which may differ in particular from those described in the foregoing specification and description, without departing from the general principle of the invention.

Claims

Claims

1. A rotary valve (10) for use with a fluid metering device, the rotary valve (10) comprising: a valve housing (12) having an inlet (16) and an outlet (18); a valve body (14) rotatably mounted with the valve housing (12); a piston (34) configured to move linearly within a cylinder (32); and an arm (46) configured to transfer linear motion of the piston (34) into rotational motion of the valve body (14) and rotate the valve body (14) 360 degrees within the valve housing (12).

2. A rotary valve (10) according to claim 1, further comprising a cam (56) attached to the valve body (14) and the arm (46).

3. A rotary valve (10) according to claim 2, wherein the cam (56) has at least one notch (62) in a surface (58) of the cam.

4. The rotary valve (10) of claim 3, further comprising at least one cam follower (64) configured to interact with the cam surface (58).

5. The rotary valve (10) of claim 4, wherein the one or more cam followers (64) are configured to interact with the cam surface (58) by rolling along the cam surface (58).

6. A rotary valve (10) according to claim 4, wherein the one or more cam followers (64) are biased towards the cam surface (58).

7. A rotary valve (10) according to claim 4, wherein the cam (56) has two notches (62) in the cam surface (58), and wherein the rotary valve (10) includes two cam followers (64) located on opposite sides of the cam (56).

8. A rotary valve (10) according to claim 7, wherein each of the two cam followers (64) is biased towards the cam (56).

9. The rotary valve (10) of claim 7, wherein the two cam followers (64) are configured to provide a force to the cam (56) to change an orientation of the valve body (14).

10. A rotary valve (10) according to claim 7, wherein a position of the two notches (62) in the cam surface (58) is correlated with an end of linear movement of the piston (34).

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