Abstract:
A constant flow distribution valve, particularly suited as the filler valve for a canning system, is constructed in the form of at least three stacked circular plates. The top or uppermost one of these plates has an elongated slot formed in it near the circumference, and oriented perpendicular to a radius of the top plate or concentrically with the circumference of the plate. This plate is mounted in a non-rotational position in the canning apparatus. A second plate and an indexing member are mounted together for rotation beneath the first plate. The second plate has its center line aligned with the center of the top plate, and includes a series of equally spaced distribution openings through it, with the openings aligned with the slot in the first plate as the second plate is rotated. Beneath the second plate is an indexing member for locating containers to be filled beneath each of the distribution openings in the second plate. The indexing member is continuouly rotated with the second plate at a rate synchronized with the rate of the supply of material to be canned through the slot. This causes a measured amount of product to be placed in each container carried by the indexing plate beneath the second plate.

Description:
BACKGROUND 
     In the canning industry, automated and semi-automated systems are employed for rapidly filling a large number of cans or other containers with food product. Because of the nature of most crops, the canning season itself is quite short, dependent upon the peak harvest time of the crops being canned. As a consequence, large volumes of foodstuffs must be processed and canned (or bottled) in a relatively short period of time. Thus, the speed and efficiency at which automated canning systems are operated is crucial to the cost effective production of the finished product. 
     Liquid products, such as juices are relatively simple to process; and a variety of efficient automated systems exist for transferring such products from large reservoirs or vessels into individual containers, which then are sealed and processed for ultimate delivery to a consumer. With respect to semi-solid products such as chiles, tomatoes, salsa and other products of similar consistency, efficient canning systems generally have not been available. 
     For canning semi-solid products such as diced chiles, salsa or the like, it has been the practice in the past to move the cans or containers to be filled by means of a conveyor past a fill position. At the fill position, it generally has been the practice to utilize a piston filler employing vacuum and cam devices to control the fill for each can located at the fill position. Such piston filler systems may have as many as fifty or more valves on one machine. All of these valves have gaskets and cams and many moving parts. As a consequence, mechanical failures can and do occur. When such failures occur, the filling machine must be shut down while repairs are made. Such down times are critical in view of the necessity of rapidly processing the foodstuffs which are to be canned. 
     The accuracy of the fill in piston type fillers also depends on the condition of the wear of the machine parts and the viscosity of the product itself. Because the viscosity can change with every batch of product, the fill varies substantially in weight from batch to batch, and even from one time period to the next, because of the variables which exist. Adjustment of piston type filler machines to fine tune the product fill is difficult, since in most such machines adjustment of one valve to fill more or less causes all of the other valves on the same machine also to fill more or less. Using of piston fill machines requires vigilant quality control to remove underweight or significantly overweight containers from the production line. 
     Another disadvantage which exists with respect to piston type filler machines used in canneries is that a large amount of spillage or dropped product occurs on these lines. As the fillers become worn and the tolerances of the various parts lose precision, significant amount of product can be lost. This product loss can be as much as 1,000 pounds per hour on each filler line. Since the product which is supplied to the cans has already undergone substantial processing (it is not raw product from the field), the cost of this wasted product is significant. Even if the piston type fillers at a plant are updated and are operating at peak efficiency, the inherent construction of these fillers is that there will be and is product loss. Even if only one ounce of product is lost per container, the total amount of product loss can be significant. For example, on a typical run it is possible to fill 250 cans per minute. At one ounce loss per can (with product value of 25 cents per ounce), on a line running for twenty hours a day, this amounts to a loss of $75,000 per day for such a line. 
     This is the loss for a relatively efficient line. It has been discovered that less efficient lines may lose over 1,000 pounds of product per hour, on each canning line. 
     It is desirable to provide an efficient distribution valve which is particularly suitable for food canning lines, which accurately fills the containers, which reduces spillage of product to a minimum, and which is mechanically simple to construct and operate. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide an improved distribution valve. 
     It is another object of this invention to provide an improved constant flow distribution valve. 
     It is an additional object of this invention to provide an improved constant flow distribution valve for use as a filler valve for canning foodstuffs. 
     It is a further object of this invention to provide an improved constant flow distribution valve employing a significantly reduced number of moving parts for use as a filler valve in a food canning system. 
     In accordance with a preferred embodiment of the invention, a constant flow distribution valve includes first and second plates mounted for relative rotation with respect to one another. The first plate has an elongated slot in it; and this slot has a pre-established length. The second plate has a plurality of uniformly spaced distribution openings through it for sequential alignment with the slot in the first plate when the two plates are rotated relative to one another. The distance between the adjacent openings in the second plate is selected to be no greater than the length of the slot in the first plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram of a canning system in which a preferred embodiment of the invention is used; 
     FIG. 2 is a detailed exploded top perspective view of features of the preferred embodiment of the invention; 
     FIG. 3 is a detailed bottom view of the components of a preferred embodiment of the invention; 
     FIG. 4 is a diagrammatic perspective view illustrating a feature of the operation of the preferred embodiment of the invention as used in a system of the type shown in FIG. 1; 
     FIG. 5 is a detail of a variation of the preferred embodiment of the invention; and 
     FIG. 6 is a detail of another variation of a preferred embodiment of the invention. 
    
    
     DETAILED DESCRIPTION 
     Reference now should be made to drawings, in which the same reference numbers are used throughout the different FIGS. to designate the same components. Initially, reference should be made to FIG. 1 which illustrates an automated canning system employing a preferred embodiment of the invention. 
     The canning system  10  shown in FIG. 1 employs a conventional can supply  12  for supplying properly oriented empty cans  13  on a conveyor  14  to a fill station  16 , which is diagrammatically illustrated to incorporate the features of a preferred embodiment of the invention. After the cans  13  have been filled at the fill station  16 , they continue to be moved by the conveyor  14  to a seamer  18 , which seals the cans  13  for further processing and labeling. With the exception of the unique features of the filler station  16  shown in FIG. 1, the portion of the automated can or container fill system shown in FIG. 1 from the can supply portion  12  to the seamer  18 , is in accordance with standard cannery practices and may be implemented in a variety of conventional forms. As a consequence, no explanation of the details of this portion of the system are considered necessary. 
     In accordance with a preferred embodiment of the invention, however, the fill station  16  employs a constant flow distribution valve consisting of four circular plates (see FIGS. 2 and 3 for details). These plates include a top plate  20  having a circular aperture  21  in it. Attached to, and located immediately beneath the top plate  20 , is another circular plate  22  with an elongated slot  23  located near its outer circumference. As shown in the embodiment of FIGS. 2 and 3, the slot  23  is a curved configuration the center line of which is concentric with the outer circumference of the circular plate  22 . 
     The plates  20  and  22  are mounted in a fixed position on a frame (not shown), which can be any suitable frame for a canning machine. This frame typically includes a portion which holds the conveyor apparatus  14  and the can supply station  12  and seamer  18 . What is important to note, however, is that the plates  20  and  22  are mounted in a fixed position as shown in FIG.  1  and in the orientation shown in FIGS. 2 and 3, as part of a constant flow fill valve for filling cans  13  supplied from the can supply  12  and passing through the fill station  16 . 
     Located immediately below the slotted plate  22  is a distribution plate  24 , having uniformly, or equi-angularly, spaced circular holes or distribution openings  25  located through it, near the outer circumference of the plate  24 . The center lines of the holes  25  are aligned with the center line of the slot  23 . The distance between the center lines of the holes  25  also is selected to be no less than the length of the slot  23  for reasons discussed in greater detail subsequently. An indexing wheel  26  is located beneath the plate  24 . The wheel  26  is attached to the distribution plate  24  for rotation with the distribution plate. 
     As is apparent from an examination of FIGS. 2,  3  and  4 , the indexing wheel  26  has a general appearance of a saw blade for a rotary saw, with a circular pocket located behind each of the outer “teeth” of the indexing wheel  26 . The pockets are selected to conform with the outer diameter of cans  13  or other containers which are to be filled by the system. As indicated in FIGS. 1,  2  and  4 , the indexing wheel is designed to rotate in a clockwise direction in the embodiment of the system which is illustrated in the various drawings. In the bottom view of FIG. 3, rotation is counterclockwise. Although the indexing wheel  26  is connected to the distribution plate  24  for rotation with the plate, there can be, and usually is, a space between the bottom of the plate  24  and the top surface of the indexing wheel  26  to allow the teeth of the indexing wheel  26  to engage individual cans  13 , as they are fed by the conveyor  14  to the filler station  16 . 
     The holes  25  through the distribution plate  24  are each located directly.over the center of the location for each of the cans  13 , which are carried by the indexing wheel  26  in the operation of the system. Consequently, product which is supplied through the distribution valve  16 , shown in detail in FIGS. 2 and 3, flows through the inlet hole  21  into the slot  23 , and then, in the manner described subsequently, through the filler holes  25  in the distribution plate  24  to enter cans  13  carried by the index wheel  26  beneath each of the filler holes  25 . 
     Reference again should be made primarily to FIG. 1 for the overall operation of the system of the preferred embodiment. In addition to the components which have been described above, the system employs a kettle  32 , into which the product to be canned is placed. This product is fed, typically by gravity, through an inlet line  34  to the input of a positive displacement pump  36 . The pump supplies the product at a constant flow rate through a line  40 , which is monitored by a product rate meter  38 . The end of the line  40  is securely attached to the hole  21  in the top plate  20  of the constant flow distribution valve  16 . This is the product input point for the system, and is diagrammatically illustrated in FIG.  1 . The hole  21  may be located at any point along the length of the slot  23 . As generally illustrated in the cross-sectional view of the valve  16  shown in FIG. 1, the hole  21  is shown as centered in the slot  23 . It could be located, however, at any point along the slot  23 . As a consequence, product flowing from the positive displacement pump  36  and supplied through the line  40  is pumped at a constant rate, to continuously keep the product flow in the slot  23 . 
     Typically, the plates  20  and  22  are made of stainless steel; and the product distribution plate  24  is made of ultra-high molecular weight (UHMW) plastic. This type of plastic is self-lubricating; so that the plate  24  is placed in frictional contact with the lower surface of the slotted plate  22 . By doing this, essentially no space is provided between the bottom of the plate  22  and the top of the plate  24 . Thus, all product flowing into the slot  23  must flow out of the slot  23  into the equal diameter distribution holes  25  in the plate  24 , as the plate  24  rotates. As noted previously, the distance between the centers of the holes  25  in the plate  24  is selected to be no greater than the length of the slot  23 . This means that as the relative rotation between the plate  24  and the slotted plate  22  takes place, there is always a uniform area total opening, equal to the area of one of the holes  25  located beneath the slot  23 . 
     As the relative rotation of the plates  22  and  24  takes place, the next hole  25  (for example, moving from 12:00 to 1:00 in the clockwise direction) begins to be filled by the leading edge of the slot  23 , while the previous hole  25 , which has passed through the entire length of the slot  23 , begins to be closed off. The point is reached when 50% of the product in the slot  23  flows into each of two adjacent holes  25 . As the plate  24  continues to rotate, the area of the previous hole  25  is closed off by the same percentage that the area of the next hole  25  is increasing , until a single hole  25  is located under the slot  23 . Thus, all of the product flow then goes into that single hole (and therefore the can  13  located beneath that hole) in the indexing wheel  26 . The total area of hole(s)  25  to which product is supplied, however, never changes. 
     It is readily apparent that the flow rate never changes under this construction. It is constant. There is no spillage, the flow rate is controlled by a drive motor  30  which rotates a shaft  28  connected to the indexing wheel  26  and the distribution plate  24 . The drive motor  30 , in turn, has its speed controlled by a control system  42 , which also controls the rate of operation of the pump  36 . These controls are effected over control lines  46  and  48 , respectively, as determined by the output of the rate meter  38  over the line  44  applied to the input of the control system  42 . Thus, synchronized operation between the drive motor  30 , which rotates the distribution plate  24 , and the operation of the positive displacement pump  36  is effected to accurately fill, without spillage, each of the cans  13  which are passed through the system. 
     FIG. 4 illustrates some of the details of the modifications to a standard system which are employed to utilize the system described above in conjunction with FIGS. 1,  2  and  3 . In FIG. 4, a top perspective diagrammatic representation of the conveyor  44  on which the cans  13  travel from the can supply  12  to the fill station  16  is shown. The conveyor  44  is a straight-line conveyor, which also is used to remove the filled cans  13  (shown on the right-hand side of FIG. 4) from the indexing wheel  26  after they have been filled. The filled cans then are moved by the conveyor  44  to the seamer station  18 , as described above. 
     It should be noted in FIG. 4 that the cans  13  which are supplied from the can supply  12  are moved by the conveyor at a sufficiently rapid rate that they back up prior to entering the feed system indexing wheel  26 . When they are removed from the indexing wheel  26 , the filled cans  13  tend to be spaced apart, as illustrated in FIG.  4 . Once again, this is standard for many canning systems. Because the different rates occur, the top surface of the conveyor  44  is made of low friction material to allow the conveyor  44  to slide under the bottoms of the empty cans  13 , as the system is operated. 
     In the operation of the system, the constantly rotating indexing wheel  26  picks off the cans  13 , one at a time. Each tooth of the indexing wheel secures a single can  13  and nests it in the circular indentation behind the tooth, as the indexing wheel  26  is rotated clockwise as viewed in FIG.  4 . To position the empty cans  13  for engagement by the end of the teeth of the indexing wheel  26 , a guide rail  50 , which curves toward the teeth and extends above the conveyor surface  44 , is provided. Thus, each of the cans  13  is picked off in turn by an individual tooth of the wheel  26 ; and then the cans are rotated by the indexing wheel  26  on a circular stainless steel rod  52 , which is located beneath the bottoms of the cans  23  carried by the indexing wheel  26 . An upper or raised circular guide rail  54  keeps the cans  13  from falling outwardly out of the filling station  16 . 
     In order to avoid confusion in the depiction of the details of the system in FIG. 4, the cans which are carried by each of the indexing teeth of the indexing wheel  26  have not been shown, as they are moved around the periphery of the indexing wheel prior to being deposited back on the conveyor  44  at the pick-off rail  58  and guide rail  56 . It should be noted, however, that there is a can  13  in every one of the indexing wheel positions, which do not lie over the top of the conveyor  44  between the rail  50  and the rail  58 . As the cans are carried by the indexing wheel  26 , their open tops also are located directly beneath a different one of the fill holes  25  in the distribution plate  24 , as described previously, since the indexing wheel  26  and distribution plate  24  rotate together. The filling then takes place in the manner described above; and full cans  13  are moved from the indexing wheel  26  by the conveyor  44  to the seamer station  18 . 
     An important feature to note with the structure of the invention described above is that conventional canning fill stations employ a linear conveyor  44 , of the type shown in FIG. 4, and also use a can supply and a seamer of the general type described previously. There is no modification to this part of the machine. What is accomplished is the replacement of the cumbersome piston pump fill mechanisms, which were employed with the linear conveyor  44 , by the simple four-piece structure described above and the portions of which are shown in detail in FIGS. 2 and 3. 
     It also is readily apparent that there are very few moving parts in this system. There are no cams, valves and levers to adust and to wear out and get out of place. Only two surfaces rotate relative to one another; and these are the lower surface of the slotted plate  22  and the upper surface of the distribution plate  24 . By selecting the material of the plate  24  to be UHMW plastic, a very low friction engagement of the surface of the plate  24  with the bottom of the stainless steel plate  22  is provided. Wear in the system thus is kept to a minimum. 
     FIG. 5 illustrates a variation of the embodiment which has been described previously. It is possible to design a variable length slot  50  from the minimum length described above in conjunction with FIGS. 1,  2 ,  3  and  4 , to one which is longer (thereby increasing the length of time each can  13  is being filled) as one way of varying the fill operation. So long as the slot  23  has a length equal to or greater than the center-to-center spacing of the fill holes  25 , it may be employed. FIG. 5 shows a curved line  50  approximately at the midpoint of the slot  23 , to illustrate a variation between a minimum length of the slot and some other greater length which may be employed, if desired. A variable length slot  23  may be designed; or a different plate  22 , having a longer slot  23  in it than the basic slot length, may be substituted for the plate  22  described above. 
     Although the foregoing description also has been made in conjunction with a curved slot, which is generally concentric with the outer circumference of the plate  22 , a straight slot  52 , as shown in FIG. 6, also may be employed. So long as the parameters described above in conjunction with the relative dimensions of the slot  52  and the holes or openings  25  in the distribution plate  24  are followed, such a straight slot also may be employed. 
     The foregoing description of the preferred embodiment of the invention is to be considered as illustrative and not as limiting. The relative number of fill openings and the particular position of the hole  21  and slot  23  may be varied without departing from the true scope of the invention. Various changes and modifications will occur to those skilled in the art for performing substantially the same function, in substantially the same way, to achieve substantially the same result without departing from the true scope of the invention as defined in the appended claims.