Apparatus and method for controlling distribution of product in manufacturing process

ES 2 198 985 T3

DESCRIPTION

Apparatus and method to control the distribution of a product in a manufacturing process.

The present invention relates generically to an apparatus and a method for controlling the delivery of a product to a manufacturing apparatus in a manufacturing process to improve the quality of the finished product. In particular, the invention relates to an apparatus and a method for controlling the distribution of food slices, such as potato chip slices, through a fryer so as to compensate for the variation in the moisture content of the slices that They exit the fryer correcting the distribution of slices by feeding the fryer across the width of the fryer to minimize variations in the moisture content of the slices throughout the fryer.

Typically commercial potato chip production involves a process in which potato slices are continuously fed into a vat of hot oil, transported through the hot oil by suitable means such as paddles, conveyors, and the like, and removed from the oil after a suitable period of time when the moisture content of the potato chips has been reduced between about 1.3% and 1.4% by weight.

The fryer, in such a process, is typically composed of an elongated tank or tank intended to contain oil for frying, at a temperature of approximately 1885 ° C (265 ° F). The oil supply inlets and oil recovery outlets are located in the reservoir to provide a circulating supply of hot oil for frying the potato slices. Potato slices are formed by feeding peeled raw potatoes into a series of centrifugal slicer heads, which cut the potatoes into generally uniform slices of suitable thickness. The slices emerging from the slicer heads then feed into a series of discharge channels that lead the slices onto a conveyor belt on which they are taken to the fryer.

Typically the positioning of the discharge channels is aimed at achieving a generally uniform distribution of the raw potato slices across the width of the fryer. However, varying conditions in the fryer such as changes in oil flow, oil temperature, movement of the potato slices, can cause the potato slices to fry unevenly, resulting in uneven frying. which can result in finished potato chips with a moisture content that varies relatively widely. Such variation in moisture content can lead to consumer dissatisfaction with the perceived freshness of the product.

Additionally, during the manufacturing process it is necessary to periodically stop the individual cutters in order to change the cutter heads as a routine maintenance procedure. In the prior art process, this has resulted in an interruption in the production of the potato chips due to the need to stop the entire line while the cutter head is removed and replaced. Typically this process involves stopping the feed of peeled potatoes to the slicers, waiting for the fed slicers to clear the line, stopping the line, removing and replacing the slicer head (s). ), the start of the feeding of peeled potatoes to the cutters, and the restart of the production line.

The need to periodically change the cutter heads represents a drawback in the production process that reduces efficiency and limits product performance. Consequently, there is a need for an improvement in the art to further improve the consistency of high product quality, and minimize production interruptions caused by the requirement for equipment maintenance.

US-A-4980187 discloses an apparatus for producing potato chips in which the position of the potato slices on the manufacturing line is not controlled.

The present invention provides an apparatus and method for improving product distribution in a manufacturing process so that consistency of product quality is increased. According to another aspect, the present invention provides an apparatus and method that eliminates interruption in a production line to carry out routine equipment maintenance.

In particular, according to a first aspect of the present invention, there is provided an apparatus for controlling the position of product units on a product manufacturing line, comprising: means for measuring a characteristic physical parameter of individual product units in a default location on that line; means for comparing a measured characteristic parameter with a predetermined value; and means for changing the position of the product units distributed on said manufacturing line as a function of the result of said comparison to thereby change the distribution profile of the product units.

Preferably, the apparatus is arranged to control the distribution of potato slices across the width of a fryer in a commercial potato chip manufacturing line, wherein the apparatus comprises a plurality of slicer heads, each provided with a supply. of potatoes and forming from the potatoes a plurality of substantially uniform potato slices, and discharging the potato slices into respective outlets thereof, a plurality of discharge channels operatively coupled to the outlets for transporting the slices to a conveyor, each discharge channel ending at a distributor to position the slices on the conveyor at a specific location, in which at least one of the distributors is rotatable controllable, a fryer to receive from the conveyor slices of potatoes to be fried and discharge into an outlet of the same potato chips produced from the slices, a plurality of sensors close to the outlet of the fryer to detect the moisture content of the potato chips exiting the fryer as a function of location across the width of the fryer, and developing signals representative of moisture content, a controller that receives the signals and compares the signals to a predetermined set of values ​​to determine whether there are variations in moisture content among the chips as a function of location across the width of the fryer, and a look-up table containing position setting values ​​for at least one rotary distributor2

ES 2 198 985 T3 controllable thorium, as a function of the states of variation of the moisture content, the controller retrieving position adjustment values ​​from the look-up table by entering certain states of moisture content variation and controlling the at least one controllable rotary distributor to rotate to a position such that the distribution of slices of potatoes on the conveyor varies in a way that reduces the variation in moisture content.

According to a second aspect of the present invention, a method is provided for controlling the position of product units (16) distributed through a product manufacturing line, comprising the steps of: measuring a characteristic physical parameter of individual units of the product at a predetermined location on that line; comparison of a measured characteristic parameter with a predetermined value; and changing the position of the product units distributed through said manufacturing line as a function of the result of said comparison to thereby change the distribution profile of the product units.

Other features, utilities, and advantages of the present invention will become apparent from the following description of preferred embodiments thereof taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic diagram of product manufacturing equipment according to a preferred embodiment of the present invention;

Fig. 2 is an elevation view of a rotary discharge chute according to a preferred embodiment of the present invention;

Figs. 3A and 3B are diagrams illustrating possible orientations of variable angle rotary discharge channels in accordance with the present invention; Fig. 4 is a flow chart of an operation of a controller in accordance with the present invention to adjust the orientation of the slice discharge channels;

Fig. 5 is a first example of a Look Up Table (LUT) containing adjustment positions of the discharge channels according to the variation of humidity;

Fig. 6 is a second example of a Look Up Table (LUT) containing adjustment positions of the discharge channels according to the variation of humidity; and Fig. 7 is a flow chart of an operation of a controller in accordance with the present invention to adjust the orientation of the slice discharge channels during a cutter head maintenance shutdown.

The present invention will be described in relation to an apparatus for producing potato chips for illustrative purposes. However, it will be apparent to those skilled in the art that the invention could be applied to any distributed product manufacturing process where the uniformity characteristics of the product depend on parameters distributed during the manufacturing process.

In a commercial potato chip manufacturing process, a supply of peeled raw potatoes feeds a plurality of centrifugal cutters 10a-10d, which cut the potatoes into substantially uniform slices with a substantially uniform thickness. Such cutters are well known in the art, see, for example, US Patent No. 4,945,794, and for this reason a description of their operation will not be provided herein.

The raw potato slices 16 are conveyed from the slicers via a plurality of discharge channels 12a-12d to a washing belt 18, in which the raw slices can be washed, prior to feeding the fryer 20, which contains a circulating supply of hot oil for frying. The slices are loaded onto the belt 18 by means of a plurality of distributor slides in the discharge channels 14a-14d. The slices are conveyed through the fryer by paddles or a similar mechanism (not shown) for a predetermined period of time, after which the resulting potato chips are removed from the fryer by a conveyor 22, such as an endless belt. The chips are then passed through a plurality of humidity sensing heads 24a-24c, which detect the moisture levels of the chips, divided according to location on the belt into left (24a), center (24b) and right (24c). Also such heads are well known in the art, and are available from Scientific Industrial Development Corporation under the designation MM55. Sensor heads 24a-24c then convert the sensed humidity levels into electrical signals and output the signals on signal lines 26a-26c to a Programmable Logic Controller (PLC) 28. Based on the humidity readings received, the PLC 28 will adjust the orientation of the sliders of the rotating discharge channels 14b and 14c to redistribute the raw slices 16 across the belt 18 to compensate and correct for variations in humidity levels. of the fries coming out of the fryer according to the left, center and right designations. Such variations can be caused by varying conditions such as oil flow through the fryer, oil temperature gradients within the fryer, slice migration, as well as other phenomena.

According to a preferred mode of operation as illustrated in FIG. 4, the PLC 28 captures the humidity readings at step S40 and averages the left, center, and right readings over a predetermined time period in the step S41. In step S42, the averaged readings are compared to programmed limits of variation to determine if significant variations in humidity level are present. For example, as shown in Figs. 5 and 6, humidity levels within an acceptable range would be classified as "0" for "within range"; levels above the margin would be classified as "H" for "high"; and levels below the margin would be classified as “L” for “low”. At step S43, the results of the comparison are entered into Look Up Tables (LUTs) such as 50 in Fig. 5 or 60 in Fig. 6, to determine if the adjustment of the sliders of the rotating discharge channels 14b and / or 14c is necessary. The settings programmed in the LUTs tables are calculated by experimentation through measurements and observations over a sufficient period of time. It is indicated that, in the preferred embodiment, the outer slides of the discharge channels 14a and 14d are fixed, and are oriented so that the slices will be positioned just inside the outer edges of the belt 18, while the slides of3

The interiors of the discharge channels 14b and 14c are rotatable. Fig. 2 is a side elevational view of chute 14b. As shown, a motor 141 drives a pulley or belt 142 that rotates a column 143 attached to the bottom of the slide 14b.

The runners of the discharge channels are rotated in order to minimize variations in the humidity level of the French fries coming out of the fryer. The possible arc of rotation of the inner slides is set between a position that places the slices in the middle of the belt 18 and a position that places the slices so that they are exactly adjacent to the corresponding outer slide of the discharge chute. Proximity sensors (not shown) detect when a chute is either at its outer limit, or in an area where collision with the other controlled chute of the discharge channel is possible. Inside the motor housing are safety switches (also not shown) to determine when the motors have reached their limit of rotation. The range of positions of each controllable slide is calibrated for a range of zero to 100, with 50 indicating the center position, zero indicating a full turn position counterclockwise (CCW), and 100 indicating a full turn position clockwise (CW). Depending on the humidity readings, a chute can be rotated by a large setting, a small setting, or no change. The degree of rotation corresponding to "large" and "small" can be properly set by trial and error. Figs. 5 and 6 provide examples of adjustments based on calculated moisture level readings. For example, as shown in Fig. 5, where the right side of the fryer has a “low” humidity reading, and the center and left sides are within the target level, the chute 14c will move counterclockwise by a “large amount. "While the chute 14b will move counterclockwise by a" small "amount. This setting has the effect of redistributing the slices through the fryer so that the right side of the fryer is fed with more slices. This is shown in Fig. 3A.

As shown in Fig. 3B, when the readings indicate that the moisture level of the potato chips on the left and right sides of the fryer is high, while the potato chips in the center of the fryer are within the range of destination, chute 14c will move a "small" increment in a clockwise direction, while chute 14b will move a "small" increment in a counterclockwise direction. This has the effect of reducing the amount of chips feeding the fryer to the left and right sides to lower the humidity levels to the target range.

The necessary settings are read from the LUTs by means of the PLC controller 28, and converted into drive signals input to the drive motors 141 via signal lines 30b and 30c.

Fig. 7 explains the operation of the PLC when it is necessary to stop a cutter, for example, to change the cutter head. In step S70, the PLC continuously monitors whether a cutting head has stopped. When a stop is detected, the current positions of the discharge channel are stored in a memory in step S71. In step S72, the controllable slides of the discharge channels are rotated to positions depending on the cutting head that has stopped, so that a uniform distribution of the slices through the fryer will be maintained.

Next, in step S73 the PLC continuously monitors whether the cutting head has been restarted. Once the PLC determines that the cutter is back in operation, the stored positions of the discharge channels are recalled from memory, and in step S74 the discharge channels are re-stored to their previous positions.

According to the invention, the system can also include a manual mode in which the positions of the discharge channels can be adjusted manually. The system also foresees some “origin” positions in which the controllable discharge channels will be oriented at the start of the line. The “home” positions are predetermined positions that represent optimal starting points to achieve the smallest variations in humidity level through the fryer at start-up.

Additionally, upward swinging gates are provided at the inlets to the slicer heads, so that the supply of raw potatoes to a specific slicer can be stopped when it is necessary to stop it for a replacement of the slicer head.