while the invention is described below with respect to a preferred embodiment , other embodiments are possible . the concepts disclosed herein apply equally to other systems for frying various types of pliable snack pre - forms and imparting a random curvature to each snack piece . the volume occupied by curved snack pieces is dependent upon the specific shape , dimensions , and arrangement of the individual snack pieces . in the present invention , randomly packed chips have a volumetric bulk density defined herein as the net weight of packaged snack pieces per the absolute volume of the container holding the snack pieces . absolute volume , as used herein , is defined as the total liquid volume of the container holding the randomly packed snack pieces . as one example , the bulk density of randomly packed snack pieces can be measured by filling a cylindrical container of known volume and subsequently measuring the net weight of the container . the container is not packed or disturbed during the filling : the pieces may settle and ultimately take up less volume when exposed to settling forces . the bulk density after being exposed to such forces is termed the settled bulk density . to control bulk density of snack pieces formed from a dough sheet , it is necessary to control the shape and curvature of each piece . however , merely creating snack pieces with curvature does not always produce higher or lower bulk densities as compared to flat pieces . a snack piece &# 39 ; s thickness , curvature , weight and orientation must be considered and potentially optimized to achieve a desired bulk density . a desired bulk density may be obtained by imparting a certain random curvature to each snack piece . snack pieces generally achieve their final shape during their transition from a rubbery state to a glass state as pre - form snack pieces are cooked , usually by frying , as explained previously and with reference to fig2 . a random curvature can be imparted to each snack piece during frying in a batch fryer using a contoured submerger while each snack piece transitions from a rubbery state to a glass state . in one embodiment , and with reference to fig3 , chip pre - forms 302 are placed in a batch fryer 320 underneath a contoured submerger 310 . as the chip pre - forms 302 cook , they are maintained against the contours of a contoured submerger 310 by buoyancy forces acting on the cooking chip pre - forms 302 . the chip pre - forms 302 are given a random shape by the contours 306 of the submerger 310 as the chip pre - forms 302 are cooked . after a certain time , the cooked chips 302 are removed from the fryer 320 and may be further processed and packaged . in another embodiment and with reference to fig5 , chip pre - forms 120 are first introduced continuously into a random frying section 106 containing frying oil 104 in a continuous fryer 102 . as randomly frying chip pre - forms 122 lose sufficient moisture , typically having from 30 to 60 percent moisture when first introduced into the oil 104 , and having about eight to fifteen percent moisture by weight when reaching a contoured submerger 512 , they no longer have a tendency to stick to one another . at this point , the rubbery chip pre - forms 124 can be submerged beneath an endless contoured submerger 512 . if frying chip pre - forms 122 reach , and are cooked under , a contoured submerger 512 with a higher than about ten percent moisture content , either in a single layer or in multiple layers , sticking and / or clumping can occur . with reference to fig5 , in a preferred embodiment , as rubbery chip pre - forms 124 reach a contoured submerger 512 , the chip pre - forms 124 are aggregated and submerged for further cooking an endless contoured submerger 512 generally does not cover the entire length of a random fryer 102 . chip pre - forms made of cereal flour and / or tuber flour have a residence time from about 15 to 90 seconds . submerged chip pre - forms 526 may overlap to a lesser or higher degree such that there are multiple layers of chip pre - forms 526 along the length of the contoured submerger 512 . while chip pre - forms 526 are losing moisture through cooking under the contoured submerger 512 , the chip pre - forms 526 are going from a rubbery state through a glass transition and into a glass state . the final shape of each piece is obtained as each chip reaches this glass state . for a typical dough formulation , when cooking chip pre - forms 526 have about five percent moisture by weight , these pre - forms may be removed from the contoured submerger 512 without affecting the final shape of the finished shaped chip product 528 . with reference to fig5 , a contoured submerger 512 in a submerging section 108 of a continuous fryer 102 has contours 516 differing substantially from the prior art . a contoured submerger 512 is not merely a submerging conveyor belt with fins , as shown in a typical prior art embodiment in fig1 . in one embodiment of the invention , a contoured submerger 512 has a v - shaped profile wherein each contour 516 has a contour height 530 . the distance between sequential contours 516 is the contour spacing 518 . in one embodiment , the contour spacing 518 is uniform from contour 516 to contour 516 . however , in other embodiments , the contour spacing 518 may be different between successive contours 516 . the contours 516 provide improved aggregation of cooking rubbery chip pre - forms 124 as they reach a first contoured submerger 512 . generally , per unit length of conveyor , there are more contours 516 than submerger fins ( 116 in fig1 ). contours are generally used in lieu of submerger fins and give improved functionality . with the use of contours 516 , each submerged chip pre - form 526 is forced under the oil 104 more consistently as the contours 516 of a first contoured submerger 512 engage the arriving rubbery chip pre - forms 124 . since the contour spacing 518 is generally shorter than the distance between sequential fins on a prior art submerging conveyor , the submerged chip pre - forms 526 move along in improved plug flow . with reference to fig5 a , while the cooking chip pre - forms are pressed upward against the contours 516 of a contoured submerger by buoyancy forces , these pieces conform to the curvature or shape of the contours 516 . because each piece 526 is located at a random place along the contours 516 , a random shape is imparted to each piece 526 . a preferred random curvature , and resultant bulk density , is obtained when the spacing between adjacent contours 518 is larger than the largest dimension of each snack piece 526 . however , other spacing of contours 518 can be used to produce finished shaped pieces 528 having a desired bulk density . the final curvature of each shaped , cooked piece 528 is dependent upon the overall profile or shape of a contoured submerger 512 , the spacing between subsequent contours 518 , the number of layers of cooking pre - forms 526 beneath the submerger 512 , and the dough formulation and shape of each pre - form 526 . a contour depth 530 of a contoured submerger 512 may be any size and may vary from contour 516 to contour 516 . however , the contour depth 530 is preferably large enough to accommodate multiple layers of cooking chip pre - forms 526 while maintaining all such pre - forms 526 in plug flow as the contoured submerger 512 directs them toward a fryer exit conveyor 114 . in another embodiment , chip pre - forms 526 are maintained for a short duration in multiple layers on a first contoured submerger 512 . the duration depends upon the moisture content of the submerged cooking chip pre - forms 526 . the chip pre - forms obtain their final shape under a first contoured submerger 512 by passing into a glass state . at this point , cooking chip pre - forms 526 may pass to subsequent submergers without losing their shape . subsequent submergers aid in cooking the cooking chip pre - forms 526 until they have a final desired moisture content ; in one embodiment , a final moisture content is about two percent by weight . a final moisture content may be as low as one percent . subsequent submergers may not be of the same shape , speed , contour , or size of a first contoured submerger 512 . subsequent submergers may even resemble prior art submergers . in a further embodiment , submerged cooking chip pre - forms 526 are not in their final shape when passed to subsequent submergers . in such an embodiment , submerged chip pre - forms 526 obtain an initial shape from a first contoured submerger 512 , and their final shape from subsequent submergers . such submerged chip pre - forms pass into a glass state under subsequent submergers . finished shaped chip products 528 are removed from the cooking oil 104 on an exit conveyor 114 . finished chip products 528 are subsequently packaged . such finished chip products generally have a lower bulk density , and thus fill more of a container , even after finished chip product packages are exposed to settling forces such as during shipping and handling . such lower bulk density generally provides finished chip products with higher consumer appeal than finished chip products having a higher bulk density . various embodiments of a contoured submerger are envisioned . fig1 illustrates some of the various profiles or contours that may be used within the spirit of this invention . in certain embodiments , contours in a continuous fryer 102 generally lie perpendicular to the flow of chip pre - forms 302 . however , the contours may run in any direction , or may have no direction or may have no uniform shape at all . the contours may even lie parallel to the flow of oil and chip pre - forms 302 in a continuous fryer 102 . the contours may be composed of a non - repeating , non - continuous set of surface features . with reference to fig1 , in one embodiment , a contoured submerger has a v - shaped profile having uniform contour spacing 1002 , or alternatively , with non - uniform contour spacing 1004 . in an alternate embodiment , a contoured submerger has a sinusoidal profile with uniform contour spacing 1006 , or with non - uniform contour spacing 1008 . in still another embodiment , a contoured submerger has a crenellated profile 1010 that may or may not have uniform contour spacing . a variation of this embodiment is a contour profile having crenellations that are each tapered 1012 , and wherein the contour spacing may or may not be uniform . in another embodiment , a contoured submerger is composed of non - uniformly sized spheres 1014 or , alternatively , conical protrusions 1016 . in a variation of such embodiment , a contoured submerger may be composed of a variety of similar shapes and / or profiles described herein . a contoured submerger may also have three dimensional contour profiles such as , but not limited to , an egg carton - like profile having peaks and valleys at regular or irregular intervals . such embodiments shown in fig1 are by way of illustration and not limitation . the following examples more fully illustrate the practice of the invention . in a first example , various contoured submergers having different shapes or contours were used to cook chip pre - forms shaped as equilateral triangles . with reference to fig3 , various shapes or profiles of a contoured submerger 310 were tested in a batch fryer 320 so as to affect the bulk density of a particular formulation and shape of snack piece . in this example , one contoured submerger 310 was shaped as a sinusoidal wave , and the bulk density of the resultant cooked snack pieces was about 7 . 5 lb / cu . ft . ( 0 . 0694 oz / cu . in . ; 0 . 120 g / cu . cm ) from that shape . using a different contoured v - shaped submerger 310 , the resultant bulk density of snack pieces was about 6 . 25 lb / cu . ft . ( 0 . 0579 oz / cu . in . ; 0 . 100 g / cu . cm ). using various shapes of contoured submergers , resulting cooked and packaged chips had a bulk density over the range from about 6 . 0 lb / cu . ft . ( 0 . 0556 oz / cu . in . ; 0 . 096 g / cu . cm ) to about 7 . 5 lb / cu . ft . ( 0 . 0694 oz / cu . in . ; 0 . 120 g / cu . cm ) when cooked with these shaped or contoured submergers . finally , a flat contoured submerger , as understood and routinely used in the prior art , was used to cook pre - form snack pieces of the same shape , the pieces cooked therewith serving as a reference . the bulk density from the use of the flat contoured submerger 310 was about 8 . 5 lb / cu . ft . ( 0 . 0787 oz / cu . in . ; 0 . 136 g / cu . cm ). in a second example of the present invention , two contoured submergers , differing from the submergers used in example 1 , and having different v - shaped profiles , were evaluated as to their effect on the bulk density of a snack product . batches of snack product pre - forms in the shape of equilateral triangles were made from a dough sheet before being batch fried . the pre - forms in example 2 were made from a dough formulation substantially different from that used in example 1 . the bulk density of pieces fried under the two contoured submergers in this example were compared against the bulk density of pieces fried under a control contoured submerger : a flat stainless steel perforated sheet or steel mesh . the two contoured submergers 404 , 406 of example 2 are shown in fig4 and both have v - shaped contour profiles . one contoured submerger 404 has contours with a larger contour spacing , or distance between successive contours , as compared to the other contoured submerger 406 . with reference to table 1 , batches of pre - form pieces were cooked with each of the three submergers described previously , and the resulting weight and volume were recorded for each sample . the control batches numbered 1 - 3 in table 1 were cooked under the control or flat submerger . with reference to fig4 , the s1 samples numbered 1 - 3 in table 1 were cooked with the submerger having the more narrow v - shaped contours 406 as compared to the contours 404 of the submerger used to cook the s2 samples numbered 1 - 3 . each batch of cooked chips of example 2 were randomly packed into a rigid cylindrical container . each batch received ten taps to simulate settling forces from shipping and handling . the volume after settling and the resultant settled bulk density of each batch are recorded in table 1 . for the control batches , the mean settled bulk density was 0 . 0506 ounces per cubic inch ( oz / cu . in .) with a standard deviation of 0 . 0032 oz / cu . in . for the s1samples , the mean bulk density was 0 . 0420 oz / cu . in . with a standard deviation of 0 . 0023 oz / cu . in . and for the s2 samples , the mean bulk density was 0 . 0366 oz / cu . in . with a standard deviation of 0 . 0010 oz / cu . in . these measurements of bulk density vary substantially from one another because of the differently shaped contours of the submerger used to cook the snack pieces . fig8 and fig9 are drawings taken from photographs of pieces packed in a cylindrical container . fig8 shows control pieces 806 packed relatively densely . in fig8 , there are many snack pieces 806 which lie substantially parallel with one another . there is substantial settling as evidenced by the void 804 at the top of the container where chip pieces 806 initially filled the container 802 . fig9 shows s2 pieces 904 packed in an identical container 802 . there are many more void spaces and there is much less settling since there is very little void space formed at the top of the container 802 . the decreased bulk density , and thus larger volume of chips in the container , is generally preferred for appearance purposes by consumers . while the invention has been particularly shown and described with reference to a preferred embodiment , it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention .
a method and apparatus to impart a random curvature to frying pre - formed snack pieces in a multi - layer fryer through the use of a contoured submerger . the shape of the contours of a contoured submerger imparts a random final curvature to each snack piece as snack pieces pass through a glass transition during frying . the contours are chosen so as to achieve a desired bulk density for the packaged fried snack products . such method and apparatus are also useful in controlling the amount of change in bulk density or amount of settling of a packaged product during shipping or handling .