Abstract:
A peeling machine for batchwise peeling of vegetable products comprises a container (6) for receiving the vegetable products and peeling means (14) in the container for removing the peel of the vegetable products during relative movement and engagement between the vegetable products and the peeling means. The bottom of the container is at least partially constituted by a number of rotatable peeling rollers (14) positioned in parallel with each other.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a peeling machine for vegetable products and the like. 
     Peeling machines for peeling vegetable products and the like are adapted either for batchwise peeling of the vegetable products or for peeling the vegetable products while these are fed through a chamber in the peeling machine from a charging end to a discharging end of the peeling machine. The peeling machine according to the present invention is intended for batchwise peeling of vegetable products. A previously known peeling machine for batchwise peeling of vegetable products comprises a container in which the vegetable products are placed. The container comprises a bottom and a side wall which in horizontal section is of substantially circular shape. In the container there are provided peeling means for removing the peel of the vegetable products while there are established a relative movement and an engagement between the vegetable products and the peeling means. In a previously known type of a peeling device for batchwise peeling the peeling means are constituted by a grinding and cutting coating on the inner surface of the side wall and the bottom of the container. The coating can for example consist of carborundum grits. The relative movement and the engagement between the vegetable products and the cutting coating is in a previously known type of peeling machine for batchwise peeling provided by the fact that the bottom of the container is constituted by a plate which is rotatable around a circular axis and when being rotated, by the influence of the centrifugal force, displaces the vegetable products towards the side wall and here displaces the vegetable products around the lower part of the periphery of the container in engagement with the cutting coating. 
     The peeling machine for batchwise peeling of the kind described above has a restricted capacity and has restrictions also in respect of the efficiency and uniformity of the peeling action. 
     The object of the invention is to provide an improved peeling machine for batchwise peeling of vegetable products. 
     SUMMARY OF THE INVENTION 
     In order to comply with this object the peeling machine for batchwise peeling of vegetable products is according to the invention characterized in that the bottom of the container for receiving the vegetable products is at least partially constituted by a number of rotatable peeling rollers which are positioned parallell to each other. 
     A peeling machine of this kind provides for a more efficient ant uniform peeling of the vegetable products than previously known peeling machines for batchwise peeling. In addition thereto it is possible in a simple way to change the capacity of the peeling machine by providing the peeling machine with two or more containers provided with peeling means and adapted to be used successively. Thereby, the first container can be adapted for coarse peeling while following container or containers is or are adapted for successively finer peeling of the vegetable products. The last container in the succession of containers can be adapted for fine peeling with water and/or knife peeling. 
     The transfer of the vegetable products between the successive containers can be provided in a simple way by the fact that the containers are designed so as to be emptied by means of tipping. 
     In a preferred embodiment of the peeling machine according to the invention at least a section of the part of the bottom of the container which is constituted by the peeling rollers forms a concavely curved surface, which is of for example elliptic shape. Thereby the peeling rollers can adjacent one side of the container be positioned in a horizontal plane taking a successively higher level in a concavely curved surface in the direction of the opposite side of the container. In the case that the curved surface is of elliptic shape the curved surface may constitute about a forth of an ellipse with the largest radius of curvature positioned at one side of the container with substantially horizontal orientation and the smallest radius of curvature positioned at the opposite side of the container with substantially vertical orientation. 
     It is preferred that the peeling rollers have at their surfaces cutting elements, for example consisting of cutting grits of carborundum provided as a coating on the rollers. Thereby the cutting elements on one or more of the rollers can be provided within surface portions which are separated from each other and between which there are provided smooth ant preferably glossy surface portions of the rollers. This provides for a substantially improved removal of peel remains from the rollers while the edges between the surface portion provided with cutting element and the glossy surface portions of the rollers can be used for providing the vegetable products with a pattern of motion promoting the peeling of the vegetable products. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention shall be described in the following with reference to the accompanying drawings. 
     FIG. 1 is a side view of a peeling machine for batchwise peeling according to the invention. 
     FIG. 2 is a plan view of the peeling machine shown in FIG. 1. 
     FIG. 3 is a schematic section of the peeling machine according to 
     FIGS. 1 and 2 on line III--III of FIG. 1. 
     FIGS. 4a and 4b are schematic sections of a peeling machine consisting of two peeling units of the kind shown in FIGS. 1-3 in operative position and discharging position, respectively. 
     FIG. 5 is a plan view of three peeling rollers of a peeling machine according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The peeling machine according to the invention is adapted for peeling vegetable products, preferably potatoes. The peeling machine is of the type for batchwise peeling, i.e. the peeling machine is supplied with a certain amount of unpeeled products, whereupon the peeling operation is conducted and the peeled product is removed from the peeling machine after which a new batch of unpeeled products is supplied to the peeling machine and so on. 
     The peeling machine is built on a frame consisting of longitudinal beams 2, posts 4, and conventional structural members. The frame supports a container 6 comprising a rear wall 8, a front wall 10 and side walls 12. The bottom of the container 6 is constituted by six parallell rollers 14 which at their end portions are rotatably journalled in the frame outside the side wall 12 of the container 6. 
     Below the rollers 14 the frame of the peeling machine supports a front collector plate 16 and a rear collector plate 18, the front collector plate 16 being connected with the front wall 10 and the rear collector plate 18 being connected with the rear wall 8. The collector plates 16 and 18 extend obliquely inwardly beneath the rollers. In the lateral direction the collector plates 16 and 18 extend somewhat outside the side walls 12. The collector plates 16 and 18 have the object of guiding waste material to a collector vessel or the like positioned below the peeling machine. 
     The front wall 10 of the container 6 has at its upper edge a portion 20 angled in forward direction and laterally projecting portions: 22 in order to facilitate the supply of potatoes to the containers 6. 
     The rollers 14 are journalled in the frame of the peeling machine in such a way that the bottom of the container provided by the rollers will form a concavely curved surface having its lower edge at the front wall 10 of the container and its highest edge at the rear wall 8 thereof. Preferably the two rollers 14 being positioned adjacent the front wall 10 are journalled on the same height while the successive rollers are journalled with an increasing height difference in relation to the previous roller so that the radius of curvature of the bottom of the containers will decrease from the front wall 10 towards the rear wall 8. At the rear wall 8 the bottom surface formed by the rollers is of substantially vertical orientation. In a suitable embodiment of the invention the concavely curved surface of the bottom corresponds to the shape of a forth of an ellipse but it is of course possible to adapt the curvature in a desired way with regard to the product to be peeled and so on. 
     At one end the rollers 14 are provided with pulleys 24 which through V-belts, a split coupling 26 and a variator 28 are driven by an electric motor 30. 
     The rollers are provided with a coating consisting of cutting carborundum grits. These carborundum grits constitute the peeling means of the peeling machine and cut or grind away the peel of the potatoes when the rollers are rotated. During the peeling the rotational direction of all rollers 14 is such that the surfaces of the rollers, which form the bottom of the container 6 move away from the front wall 10 towards the rear wall 8. When the potatoes shall be peeled a suitable amount of the potatoes is charged in the container 6, the charging taking place while the peeling rollers 14 are stationary or rotate slowly in the peeling direction. If the peeling machine is dimensioned so that the peeling rollers 14 have a length of about 2.5 meters and a diameter of 105 mm a suitable charge weight for potatoes is 80-100 kg. When the potatoes have been charged in the container 6 the rotational speed of the peeling rollers 14 is increased by means of the variator 28 to a suitable value, the potatoes being thereby subjected to the influence of the carborundum grits of the peeling rollers 14 which provides that the peel of the potatoes are cut or ground away at the same time as the potatoes circulate from the front wall 10 of the container up to the highest roller at the rear wall 8 from which the potatoes are thrown back to the front wall 10 of the container. 
     The peel remainders fall down to the bottom of the peeling machine below the rollers 14 and are directed to some kind of suitable collecting vessel or other collecting place by means of the collector plates 16 and 18. After the peeling has been completed the peeled potatoes are discharged from the container 6. This can be provided by tipping the container 6 which can be provided in respect of an axis, not shown, extending parallel to the rollers 14 in the vicinity of the upper edge of the rear wall 8. As an alternative the discharging can be accomplished by providing the front wall 10 of the container with an openable door (not shown). After the door has been opened the container can be emptied by rotating the rollers 14 in the opposite direction of rotation in relation to the direction of rotation used for the peeling. 
     The capacity of a machine for batchwise peeling according to the invention can be increased by providing the peeling machine with two or more units of the kind shown in FIGS. 1-3. As schematically shown in FIGS. 4a and 4b the peeling machine can consist of two units 32 and 34, each unit being constructed in the same way as the peeling machine according to FIGS. 1-3. The peeling operation is hereby divided into two phases, in which the first phase which can consist of a coarse peeling without water is conducted in the unit 32. After the first phase has been completed the potatoes are tipped over to the unit 34 as shown in FIG. 4b, whereupon the final peeling which is constituted by a fine peeling and can be conducted with the addition of water is conducted in the unit 34. It is realized that the peeling device according to FIGS. 4a and 4b is operated so that the unit 34 is operating with fine peeling of a previous batch while the unit 32 is operating with coarse peeling of a new batch. The peeling machine can be constructed so as to include a desired number of units so that the peeling operation can be conducted in the most suitable way. 
     In FIG. 5 there is shown a plan view of three peeling rollers 36, 38 and 40 in a modified embodiment of a peeling device according to the invention. Conventional peeling rollers can be provided by helically winding the smooth cylinder surface of the rollers by means of a strip coated with carborundum, which is bound to the surface of the roller by means of a two component binding agent. According to the previously known technique the strip is wound with the edges close to each other so that the roller obtains the appearance of the roller 38 in FIG. 5. Here the carborundum strip is designated with reference numeral 42 while the edges of the strip engaging each other are designated with reference numeral 44. 
     In a modified embodiment of the peeling machine according to the invention the carborundum coating of the peeling rollers are positioned within surface portions separated from each other and between which smooth and preferably glossy surface portions of the rollers are provided. According to FIG. 5 this has been accomplished by winding the carborundum strip 42 onto the rollers 46 and 40 with a distance between the side edges 44 of the strip 42 so that surface portions 46 of the smooth surface of the roller are exposed between the side edges 44 of the carborundum strip 42. The carborundum strip 42 is wound in opposite directions on the rollers 36 and 40 so that the surface portions 46 will form on the rollers a right helix and a left helix, respectively. 
     The smooth surface portions 46 between the carborundum coating contribute to the action of subjecting the potatoes to movements during the peeling operation contributing to the efficiency and uniformity of the peeling. The smooth surface portions 46 also contribute to the efficient removal of the peel remainders from the rollers. 
     A peeling machine according to the invention can in a desired way be constructed of two or more units of the kind shown in FIGS. 1-3 and can be provided with different types of peeling rollers according to the principles shown in FIG. 5.