Cleaning-in-place system for flat belts

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DESCRIPTION

Cleaning-in-place system for flat belts.

Cross reference to related requests

The present application claims the benefit of US Patent Application No. 12 / 856,578 filed August 13, 2010, the disclosure of which is incorporated herein by reference, and US Patent Application No. 12 / 288,602, filed on October 22, 2008, which is a continuation in part of US Patent Application No. 11 / 672,568, filed February 8, 2007, the disclosures of which are incorporated herein by reference.

Field of the invention

The present invention relates to a flat belt conveyor apparatus.

Background of the invention

The pinions for driving flat belts are generally made of stainless steel or plastic that is machined or molded. In food processing applications, pinion drives are a particularly critical area for cleaning. It is important to be able to periodically remove debris from the sprockets and on the back side of the belt to avoid bacterial growth and spoilage of processed foods on the belt. For this purpose the pinions have been designed with large openings to allow a cleaning medium to pass from the side and reach the critical areas to be cleaned. Such pinions are disclosed for use with modular belts in US 2009/0050185 A1, according to the preamble of claim 1. However, such pinions are not ideally suitable for use with flat (non-modular) belts. For example, as illustrated in Figures 7A-7B, the shape of the teeth, and the lack of support between adjacent pairs of teeth, allow a flexible band to buckle as it is forced around the periphery of the pinion while the band is under tension. Over time, this buckling causes belt damage including cracks in the belt surface.

Accordingly, there is a need for an improved cleaning system that incorporates a pinion for use with flexible belts and that avoids the drawbacks described above.

Summary of the invention

The present invention satisfies the need described above by providing a cleaning-in-place system according to independent claim 1. Preferred embodiments will emerge from the dependent claims.

The present invention provides a sprocket for a flat belt. The flat band may have transverse ribs. The pinion rotates around a tree. The pinion is provided with a central opening to receive the shaft. The pinion is provided with a plurality of teeth arranged around the periphery of the body. The teeth are angularly spaced about the axis such that each tooth is separated from adjacent teeth by a first opening, for the application of a cleaning or other means as discussed in greater detail herein. Each tooth is provided with a contact surface with the band, which is convex in shape such that the outermost periphery of the pinion is usually circular. The belt-contacting surfaces of the teeth guide the belt around the periphery of the pinion in order to minimize the belt's ability to buckle.

The first opening can be circular, trapezoidal, or any other shape. The first opening is configured to expose the underside of the web to the cleaning medium.

The teeth may each further comprise a second tooth such that pairs of teeth are arranged around the periphery of the body, each pair being separated from the adjacent pair by the first opening. Each tooth of a pair of teeth may be separated from the other tooth of the pair by a second opening. The second opening is configured to engage a rib on the band. The second openings may be configured to be larger than the corresponding ribs to allow cleaning medium to pass between the pinion and the ribs.

A cleaning system may be arranged in the vicinity of the sprockets such that a cleaning medium is sprayed through the first opening into the opening arranged adjacent the underside of the band when the band engages the sprocket. The cleaning system may include a dispenser in combination with spray nozzles that are pointed towards the sprocket and / or belt.

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Brief description of the drawings

The invention is illustrated in the drawings in which similar reference characters designate the same or similar parts in all the figures of which:

Figure 1A is a perspective view of a pinion suitable for use with a flat belt.

Figure 1B is a side elevation view of the pinion of Figure 1A.

Figure 1C is an end elevational view of the pinion of Figures 1A and 1B.

Figure 2 is a side elevation view of the pinion of Figures 1A-1C with a flexible band coupled therewith.

Figure 3 is a perspective view of two pinions and a flat band engaged with them.

Figure 4A is a perspective view of another pinion suitable for use with a flat belt.

Figure 4B is a side elevation view of the pinion of Figure 4A.

Figure 4C is an end elevational view of the pinion of Figures 4A and 4B.

Figure 5 is a side elevational view of the pinion of Figures 4A-4C with a flexible band coupled therewith.

Figure 6 is a perspective view of two pinions with a flexible band engaged with them.

Figure 7A is a side elevational view of a prior art pinion.

Figure 7B is a side elevational view of the prior art pinion with a flexible band coupled therewith.

Figure 8 is a perspective view of a belt running over sprockets and a cleaning-in-place system of the present invention, with a portion of the belt removed for clarity.

Figure 9 is a side view of the clean-in-place system of Figure 8, with one side and part of the strip removed for clarity.

Figure 10 is another side view of the clean-in-place system of Figures 8 and 9, with additional parts removed for clarity.

Figure 11 is a front view of the clean-in-place system of Figures 8-10 with the band removed for clarity.

Figure 12 is a rotated view of a part of a cleaning-in-place system according to an embodiment of the present invention.

Figure 13 is another rotated view of the part of the cleaning-in-place system of Figure 12.

Detailed description of the invention

Figures 1A-1C illustrate a pinion 10 provided with a body 12 which may be constructed of stainless steel, plastic or other suitable materials generally known to be food compatible and easy to clean. Pinion 10 includes a central aperture 14 for engaging a shaft (not shown). The shaft can be a motor shaft. The central opening 14 may be shaped to cause the pinion 10 to rotate as the shaft is rotated; for example, the central opening 14 may be in the shape of a square. In this way, the pinion 10 can rotate about a geometric axis 15 that is coincident with the shaft in order to drive a band 90 (see, for example, figure 2). Pinion 10 can be an idle pinion that is rotated about axis 15 by movement of belt 90 around pinion 10. Central aperture 14 can be formed in other shapes to accommodate different shaft geometries as will be apparent to those of ordinary skill in the art based on this description.

The pinion 10 is provided with a plurality of teeth 16, 18 arranged in pairs 20 around the periphery of the body 12. Each tooth 16, 18 is provided with a band contact surface 26. The band contact surface 26 It is convex in shape such that the outermost periphery of pinion 10, as defined by the band contacting surfaces 26 of teeth 16, 18, is substantially circular. The discontinuous circle formed by the contact surfaces with the band 26 of the teeth 16, 18 is centered on the axis 15

ES 2 581 663 T3 and guides the band 90 around the periphery of the pinion 10 in order to minimize the buckling capacity of the band 90.

The pairs 20 of teeth are angularly spaced about axis 15 such that each pair 20 of teeth is separated from adjacent pairs 20 of teeth by a first opening 22. The first opening 22 is configured to align with the underside of the band 90 when band 90 is engaged with pinion 10 as best shown in Figures 2 and 3. In this manner, the first opening 22 allows a cleaning medium sprayed substantially towards the pinion 10 and the band 90 to reach the underside of the band 90. The first opening 22 may be configured to allow access of the cleaning means to band 90 while maintaining a necessary amount of contact surface with band 26 of teeth 16, 18 to prevent buckling of band 90. The cleaning medium may comprise a liquid, a gas, a mixture of liquid and gas, a powder, a foam or any other form suitable for cleaning (collectively referred to as a cleaning medium, fluid or fluid). The medium can also serve other purposes in place of or in addition to cleaning such as sanitation or drying.

In the non-limiting example illustrated in Figures 1B and 2, the first opening 22 has a circular shape, where a chord of the circle intersects the periphery of the pinion 10 thus forming edges 28, 30. As such, the wide circular first aperture formation 22 allows circulation of a sufficient amount of the cleaning medium, while the smaller peripheral clearance created by edges 28, 30 allows the appropriate web contacting surfaces 26 to remain in the holes. teeth 16, 18. The appropriate size of the gap created by edges 28, 30 will depend on the specific application. For example, the stiffness of the belt and / or the number and spacing of the ribs in the belt will require more or less support by the belt-contacting surfaces of the sprocket teeth. The edges 28, 30 or any edges formed by the described pinion elements may be beveled, rounded, or the like. The gap formed by the edges 28, 30 can be considered a web interface portion 38 of the first opening 22. Said band interface portion 38 may be narrower than the largest possible diameter (or dimension) of the first aperture.

Another embodiment of a pinion 50 is illustrated in Figures 4A-6, in which the first opening 62 is trapezoidal. Other suitable shapes and sizes for the first opening will be apparent to those skilled in the art based on this description. The first opening can also comprise multiple openings. As such, a band can be exposed to the cleaning medium in more than one position between the ribs of the band.

The contact surfaces with the band 26 of the pinion 10 may constitute about 50 percent of the circumference of the pinion 10 (the first openings 22 and the second openings 24 constitute the other 50 percent of the circumference). Belt contacting surfaces 26 may constitute more or less than 50 percent of the circumference of pinion 10 depending on the application (eg, belt stiffness, number and spacing of ribs, etc.) .

Each tooth 16, 18 of a pair 20 of teeth may be separated from the other tooth 18, 16 of pair 20 by a second opening 24. The second opening 24 is configured to mate with a rib 92 of the band 90. The second opening 24 it may have, for example, but not limited to, a tapered section to engage a tapered rib 92. The second opening 24 may be configured to be larger than the corresponding rib 92. For example, a depth d of the second opening 24 can be greater in length than a height h of the corresponding rib 92. In this way, the cleaning means can pass between the pinion 10 and the rib 92, while the band 90 is engaged with pinion 10 in order to sweep contaminants from the area of ​​ribs 92 of belt 90.

The body 12 of the pinion 10 may have a varying longitudinal width. For example, as best shown in FIG. 1A, an inner portion 32 of the body 12 may have a width Wi that is less than a width W_or of an outer portion 34 of the body 12. In this way, the volume of material required for the body 12 and the mass of the body 12 can be minimized (due to the relatively narrow width Wi of the inner portion 32), while still providing a large contact area with the web 26 (due to the relatively large width Wo of the outer portion 34). The body 12 may further have a transition portion 36, where the width gradually increases from Wi to Wo.

The reduced width Wi of the inner part 32 also has the advantage of improving the access of the cleaning medium to the underside of the band 90, especially to a part of the band 90 that is located between two pinions (see, for example, Figure 8, showing where a V-shaped spray of the cleaning medium can be less hampered by a reduced width Wi).

Turning to Figure 2, pinion 10 is shown engaged with belt 90. Belt-contacting surfaces 26 of teeth 16, 18 engage the belt and facilitate its passage around the periphery of pinion 10 and the latter. Openings 24 engage with transverse ribs 92 of band 90. In addition, the first openings 22 provide large openings and improved access to the underside of belt 90 for cleaning as belt 90 passes over pinion 10, while still maintaining a contact surface with the belt.

ES 2 581 663 T3 band 26 sufficient to minimize the risk of buckling of band 90. The relationship of the first openings 22 and the inner part 30, the transition part 34, and the outer part 32 of the pinion can allow an improved access of the cleaning means to the band 90. Similarly, the variable width of the body 12 in the second openings 24 may allow improved access of the cleaning means to the ribs 92.

The sprockets described above are designed in such a way that the underside of the belt is substantially accessible regardless of the position of the sprocket. This pinion design in combination with the spraying techniques described in detail below provides optimal cleaning of the flat belts. As shown in Figures 8-13, spray nozzles 300 are located on a pinion shaft 303. Shaft 303 comprises a stationary hollow shaft or thick-walled tube. Pinions 301 rotate on shaft 303 which may be constructed of steel or other material or may be coated with a ceramic or plastic coating. Cleaning medium enters through inlet 304 and passes through hollow shaft 303 and exits shaft 303 as a spray 302 through nozzles 300. As best shown in Figures 11-13, nozzles 300 are arranged primarily on shaft 303 between the pinions. There may also be a nozzle 300 located at the end of a curved section 307 extending from the end of shaft 303. The placement of nozzles 300 on shaft 303 provides an optimum spray angle α as described in greater detail below. continuation. The sprays 302 are designed to be substantially flat (best shown in Figure 13) to minimize consumption of the medium and to improve the ability of the spray to enter the openings k (Figure 9) between the pinion teeth 311 and into the bottom 308 of band 306.

As described in more detail below, the best cleaning performance with minimal cleaning medium consumption is achieved with a combination of spray angle and pressure, relative to the pinion diameter (i.e., the distance from the spray nozzle). spraying the belt surface). The temperature of the cleaning medium also has to be adapted to the specific process. Also, the supply of the cleaning medium can be controlled by a tailored program to limit the spraying time for the lowest possible consumption of the cleaning medium. The program can be tailored to the specific requirements of the customer's production process.

As shown in Figure 8, the clean-in-place system of the present invention can be installed on the idle or non-driven shaft 303 of a flat conveyor belt 306. The belt 306 rides on a plurality of sprockets 301. The sprockets 301 are rotatably mounted on the stationary hollow shaft or thick-walled tube 303. The shaft 303 is equipped with a series of spray nozzles 300 positioned between the pinions 301. The spray is directed to the underside 308 of the band 306 as it passes over the pinions 301. The spray is directed approximately radially. As described above, the design of the pinion 301 is made in such a way that the underside 308 of the band 306 is largely uncovered and therefore the cleaning means can impinge on the underside.

Turning to Figure 12, the clean-in-place system is shown with band 306 and other components removed for clarity. The distance d between the center lines 330 of the adjacent pinions 301 determines the distance that the spray must travel and is determined by the spray angle α. With a larger spray angle, the pinions 301 could be positioned further apart. As shown, a pair of brackets 329 hold stationary shaft 303 in position. Spray patterns overlap on each side.

Turning to Figure 11, the overlap of the sprays is sufficient to allow the cleaning medium to impinge on the underside of the belt through the openings k between the teeth of the pinions.

In Figure 13, the spray nozzles 300 have a spray pattern 302 that is substantially flat and therefore can better enter the openings k between the teeth of the pinions and, to enter the engagement clearances with the ribs. The nozzles 300 are aligned at an angle β to the center line 340 of the shaft 303. This angle can be between five and fifteen degrees, and is preferably ten degrees. This angle prevents disturbances between the spray patterns of adjacent nozzles 300 and ensures penetration of the spray medium through the openings and gaps from both sides of the pinion. As a result of the overlap, the surface of the strip can be completely covered.

The following table illustrates the spray setting for a sprocket with a pitch diameter of 165mm.

<td>Pinion pitch diameter</td><td>165 mm (6.5 in.)</td>

<td>Nozzle type</td><td>Lechler 612,487. 16</td>

<td>Spray angle</td><td>120 degree</td>

<td>Spray alignment</td><td>10 grades</td>

<td>Pinion / Nozzle Increase</td><td>150 mm (6 in.)</td>

<td>Number of nozzles per belt width</td><td>6 / m (2 / ft.)</td>

<td>Fluid pressure (bar)</td><td>2-10 bar (8 bar preferably)</td>

<td>Fluid consumption at 8 bar / nozzle</td><td>3.19 liters / min.</td>

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Pinion pitch diameter must be no less than 130mm (5in) and no more than 200mm (8in). For other sprocket sizes, spray angles and / or spray / sprocket distances can be adjusted. The nozzle identified above is from a well-known brand that is commercially available from various sources. Other nozzles would also be suitable as will be apparent to those skilled in the art based on this description.

A cleaning-in-place system of the present invention may further comprise an upper surface cleaning manifold 380 that includes spray nozzles 382 configured to spray cleaning medium on the upper surface 384 of web 306 (see, for example, Figures 8, 10, and 11).

Although the invention has been described in relation to certain embodiments, it is not the intention to limit the scope of the invention to the particular forms set forth, but rather to cover such alternatives, modifications, and equivalents that may be included within of the scope of the invention as defined by the appended claims.