Vacuum frying chamber provided with a centrifugal separation apparatus

Abstract: A centrifugal separation apparatus comprises a rotatable cylindrical member (136) including a side perforated wall and an opened bottom and a bottom lid member (138) including a central raised portion and a side wall inclined downwardly and outwardly. The bottom lid member (138) is moveable between an upper position in which said bottom lid member (138) is engaged by the lower end face of said cylindrical member (136) and a lower position in which said bottom lid member (138) is spaced apart from the lower end of said cylindrical member (136) to form a gap therebetween.

Description: The present invention relates to a vacuum frying chamber provided with a centrifugal separating apparatus which is suitable for use in the centrifugal separation of frying oil from fried foodstuffs. Japanese Patent Application Disclosure No. 61-181554 discloses a centrifugal oil separation apparatus which comprises a rotatable cylinder including a plurality of small apertures for separating frying oil, and a rotary chip receiving member for temporarily storing the frying oil, the rotary chip receiving member being located coaxially to the cylinder and including a central recess on the internal bottom wall thereof. Oily chips (e.g. small waste pieces produced by stamping) are charged into the rotatable cylinder through the top opening thereof and temporarily stored on the rotary chip receiving member. Thereafter, the chip receiving member is rotated such that the oily chips move from the rotary chip receiving member to the inner wall of the rotatable cylinder under the action of the centrifugal force created by rotation of the chip receiving member. The oily chips that so move onto the inner wall of the rotating cylinder are urged against that inner wall under the action of the centrifugal force created by rotation of the cylinder. In such a manner, oil can be separated from the oily chips under the influence of the centrifugal force. After completion of the separating operation, the rotation of the cylinder is stopped. As a result, the chips will drop from the inner wall of the cylinder under gravity. Japanese Utility Model Disclosure No. 60-168558 describes a centrifugal hydroextractor for separating water and/or oil from various industrial materials or articles such as bolts, rivets or the like. The centrifugal hydroextractor comprises a rotary cylindrical member which has top and bottom openings and an intermediate portion having a diameter larger than those of the top and bottom portions of the cylinder. When the cylindrical member is rotated, the materials or articles placed therein move from the central conical-shaped guide member to the inner wall of the intermediate portion of the cylindrical member under the action of centrifugal force. Thus, water can be extracted from the materials or articles on the inner wall of the cylindrical member. When the rotation of the cylindrical member is topped, the materials or articles drop from the inner wall of the cylindrical member onto a sliding surface located below the cylindrical member under gravity. The materials or articles can be discharged from the centrifugal hydroextractor along the sliding surface. In any event, the prior art centrifuges are adapted to rapidly move the oily materials or articles from the central position in the rotating cylinder to the inner wall thereof. Thus, fragile materials or articles such as fried foodstuffs may be easily damaged. In the prior art centrifuges, furthermore, the materials and articles may be firmly deposited on the inner wall of the rotating cylinder, depending on the properties of the oil to be separated and the shape and properties of the materials or articles. Even if the cylinder is stopped, the materials or articles may not drop from the inner wall of the cylinder under gravity. In particular, if the material to be centrifugally treated is a vacuum fried product, clogging may be caused by the fried product being deposited on the inner wall of the cylinder. If the fried product is subjected to centrifugal force many times as it is deposited on the inner wall of the cylinder, the fried product may be cooled and hardened too much, resulting in a fragile product which may be easily damaged. Such fragile products may be highly different from the other products in the amount of oil contained therein. US-A-2,932,401 describes a centrifugal apparatus of the type specified in present claim 1, but said apparatus is used for removing water from relatively light bulky products as leafy vegetables EP-A-0056511 discloses a centrifuge comprising a drum, a drive system for rotating the drum, and an inlet for supplying contaminated liquid to the drum, the drum having at least one orifice in its upper part to permit the discharge of filtered liquid. For cleaning the drum of accumulated contaminants, the drum is provided with an aperture in its lower part, a closure member movable between a position in which the aperture is closed by the closure member and a position in which the aperture is open, and a cleaning member disposed within the drum for rotation about the axis of the drum. There are provided means for moving or allowing the closure member to move into its position uncovering the aperture during a cleaning operation, and means for establishing relative rotation between the cleaning member and the drum. In view of the problems in the prior art centrifuges, it is an object of the present invention to provide, for a vacuum frying chamber, a centrifugal separating apparatus which can damage fried foodstuffs subjected to the centrifugal action to a lesser extent. Another object of the present invention is to provide, for a vacuum frying chamber, a centrifugal separating apparatus in the case of which fried products or oily materials that have been subjected to the centrifugal action can reliably drop from the inner wall of the rotating member. The present invention provides a vacuum frying chamber provided with a centrifugal separation apparatus for the centrifugal separation of fried foodstuffs from frying oil, with solids discharge from the apparatus being controlled by a reciprocating bottom closure member, said apparatus comprising: a cylindrical member rotatable about a vertical axis and including a lower end and a perforated vertical side wall, said perforated vertical side wall having an inner surface, said cylindrical member having an open bottom at said lower end and an interior defined by said perforated vertical side wall; a bottom closure member rotatable about said vertical axis and including a lower end, a central raised portion, and an inclined side wall extending downwardly and outwardly from said central raised portion and terminating at said lower end of said bottom closure member, said bottom closure member being movable between an upper position in which said lower end of said bottom closure member is engaged with said lower end of said cylindrical member and said central raised portion and said inclined side wall are positioned within said interior of said cylindrical member, and a lower position in which said lower end of said bottom closure member is spaced apart from said lower end of said cylindrical member and at least a portion of said inclined side wall is withdrawn from said interior of said cylindrical member; scraper means for scraping fried foodstuffs accumulated on said inner surface of said perforated vertical side wall of said cylindrical member, said scraper means being rotatable about said vertical axis, and said scraper means including at least one scraping element that is supported by a rib and that is substantially in contact with said inner surface of said perforated vertical side wall of said cylindrical member; and hopper means located eccentrically with respect to said vertical axis of said cylindrical member; wherein said scraping element is (i) a linear scraping element extending linearly in a direction parallel to the rotational axis of the cylindrical member or (ii) a spiral scraping element, for scraping fried foodstuffs accumulated on said inner surface of said perforated vertical side wall of said cylindrical member. For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a view showing the arrangement of one embodiment of a centrifugal separation apparatus for use in accordance with the present invention; Figure 2 is a cross-sectional view of the centrifugal separation apparatus of Figure 1; Figures 3A and 3D illustrates the centrifugal separation apparatus of Figure 1 in various operating positions; Figure 4 is a side view showing, partially in cross-section, an example of the scraper means of the apparatus of Figure 1; and Figure 5 is a plan view of the scraper means shown in Figure 4. Referring to Figure 1, there is shown a centrifugal separating device 4 to be connected to a vacuum frying chamber and adapted to separate the frying oil from the fried products. The centrifugal separating device 4 is located below a hopper means 111. The hopper means 111 is in turn disposed below the discharge port of the vacuum frying chamber. The hopper means 111 includes an endless conveying belt 112 formed of a thin and surfaced finished sheet of stainless steel. The endless belt 112 is spanned between upper and lower pulleys and a tension roller. The endless convey belt 112 is engaged by a doctor knife at a position wherein the belt passes over the lower pulley. The hopper means 111 includes a shutter at the lower end thereof. As seen from Figure 2, the centrifugal separating device 4 comprises a centrifugal separating device 4 comprises a centrifugal separator 122 for receiving the fried products from the hopper means 111; a drive 124 for driving the centrifugal separator 122; a hopper 130 disposed below the centrifugal separator 122, the hopper 130 having an airtight shutter 129 at the lower end thereof; and an oil collecting container 131 for collecting the oil separated from the products by means of the centrifugal separator 122. As shown in Figures 3A to 3D, the centrifugal separator 122 is integrally mounted on a rotating drive shaft 132 which in turn is connected to the drive 124. The centrifugal separator 122 comprises a cylindrical member 136 including a number of small apertures 134 formed therethrough; a bottom closure member 138 reciprocatable between a position in which the closure member 138 engages the lower end portion of the cylindrical member 136 without any gap and another position in which the closure member 138 is spaced apart from the lower end portion of the cylindrical member 136 to form a gap through which the fried products can pass; and a drive 140 for moving the bottom closure member 138 vertically between said two positions. The closure member 138 is substantially of a conical configuration and has a central raised portion and a horizontal flange 139 on the peripheral edge thereof. The closure member 138 is biased upwardly under the action of a coil spring 144 which is mounted about a spring core member 142 extending downwardly from the lower end of the rotary shaft 132. Normally, the closure member 138 engages the lower end face of the cylindrical member 136 to close the bottom opening thereof. The drive 140 comprises a drive shaft 146 and a C-shaped arm member 154 mounted on the forward end of the drive shaft 146 and adapted to engage in a circumferential groove which is defined by two flanges 150 and 152 on the spring core member 142. The operation of the centrifugal separating device 4 will now be described with reference to Figures 3A and 3D. As shown in Figure 3A, the closure member 138 is biased against the cylindrical member 136 to close the bottom opening thereof, under the biasing force of the coil spring 144. If a given amount of products are accumulated in the hopper means 111, the shutter thereof is opened to charge the products into the centrifugal separator 122. The charged products accumulate in the space defined by the cylindrical member 136 and the closure member 138, at its lower section. Subsequently, as shown in Figure 3B, the rotary drive 124 is energized to rotate the cylindrical and closure members 136 and 138 as a unit through the drive shaft 132. For example, the rotational velocity may be set at 300 - 1,500 revolutions per minute. In such a manner, the products move along the internal face of the cylindrical member 136. Since the outer wall of the closure member 138 is raised at its centre and inclined outwardly, the products will not concentrate on the bottom face of the cylindrical member 136, but will spread over the inner wall of the cylindrical member 136. Thus, the oil can be separated from the products substantially uniformly. The separated oil flows outwardly through the small apertures 134 in the cylindrical member 136 and collect in the oil collecting container 131. The collected oil is discharged from the oil collecting container 131 to an external reservoir through piping (not shown) which has airtight shutter means. Subsequently, all the rotational motion of the rotating components is stopped. As shown in Figure 3C, the products again drop into the lower portion of the space defined by the cylindrical and closure members 136 and 138. As shown in Figure 3D, subsequently, the drive 140 is energized to move the closure member 138 downwardly against the biasing force of the coil spring 144. As a result, said gap will be formed between the lower end face of the cylindrical member 136 and the closure member 138. The products drop into the hopper 130 through said gap. Thereafter, the drive 140 is de-energized to allow the closure member 138 to move upwardly under the action of the coil spring 144. Thus, the bottom opening of the cylindrical member 136 is closed by the closure member 138, as shown in Figure 3A. The airtight shutter 129 of the hopper 130 communicates with a product discharge chamber 160, as shown in Figure 1. The discharge chamber 160 is provided, at its lower end, with a pressure shutoff valve 161 for discharging the products. The discharge chamber 160 also includes a pressure regulator 162 which is used for returning the interior of the chamber 160 from vacuum to normal pressure. It is preferred that the discharge chamber 160 further includes a cooling apparatus 163 which can cool and set the products such that the products will be effectively prevented from deforming on returning the discharge chamber 160 from the vacuum to normal pressure. When a predetermined amount of products are accumulated in the hopper 130, the airtight shutter 129 is opened to drop the products into the discharge chamber 160. Thereafter, the airtight shutter 129 is closed. The cooling apparatus 163 is then energized to cool the products to a predetermined temperature. The pressure regulator 162 is subsequently energized to return the internal pressure of the discharge chamber 160 from vacuum to normal pressure. Finally, the pressure shutoff valve 161 is opened so that the products can be removed. The centrifugal separator 122 further includes a scraper member 204 having ribs 200 and scraping elements 202 each attached to the outer end of one of the ribs 200. The scraper member 204 is mounted on the closure member 138 for rotation therewith. When the closure member 138 is downwardly moved while being rotated after the oil separating operation has been completed, the scraper member 204 also is rotated with the scraping elements 202 thereof, thereby being slidably moved on the inner wall of the cylindrical member 136. As a result, products deposited on the inner wall of the cylindrical member 136 can be reliably scraped and dropped therefrom. Although in the above embodiment the scraper member is attached to the closure member 138, the embodiment illustrated in Figures 4 and 5 provides for the scraper member 204 to be attached to the rotating drive shaft 132. After the centrifugal oil separation has been terminated, the scraper member is rotated in a horizontal plane to scrape the products off the inner wall of the cylindrical member 136. In accordance with the present invention, the scraping elements 202 are spiral scraping elements, such as show in Figures 4 and 5, or are scraping elements that extend linearly in a direction parallel to the rotational axis. The vertical length of each of the scraping elements is selected such that all the products can be scraped from the inner wall, depending on the rotational velocity of the bottom closure member 138 and the velocity of downward movement of the bottom closure member 138. However, the scraping elements may be designed so as to scrape the products off only that part of the inner wall of the cylindrical member 136 on which the products can more easily deposit. In a further preferred embodiment of the present invention, at least one of the cylindrical and closure members 136 and 138 can be rotated independently. After the centrifugal oil separation has been terminated, the products can be scraped from the inner wall of the cylindrical member 136 by rotating the cylindrical member 136 or the closure member 138 independently. The drive 124 for rotatably driving the centrifugal separating device 4 may include a high-performance braking device (not shown). After the centrifugal oil separation has been completed, the cylindrical and closure members 136 and 138 can be abruptly stopped by the braking device. As a result, the products deposited mainly on the cylindrical member 136 and partially on the closure member 138 can be separated therefrom under inertia. Even if the products are not entirely separated from the cylindrical and/or closure members, they can be more easily removed manually therefrom. The arrangement may be modified such that only at least one of the cylindrical and closure members 136 and 138 is stopped instantaneously. In a further embodiment of the present invention, the closure member 138 may be again moved upwardly at a higher velocity and engaged by the lower end face of the cylindrical member 136 with an impact after the closure member 138 has been moved downwardly to scrape the deposited products into the hopper 130. Thereafter, the closure member 138 is then moved downwardly again. In such a manner, the products remaining on the cylindrical and closure members 136 and 138 can be separated therefrom to pass into the hopper 130. In a further embodiment of the present invention, the drive 124 may include a vibrator (not shown). After the centrifugal oil separation has been terminated and the closure member 138 has been moved downwardly, the cylindrical and closure members 136 and 138 may be vibrated such that the products remaining thereon can be more readily separated to pass into the hopper 130.

Claims: A vacuum frying chamber provided with a centrifugal separation apparatus (4) for the centrifugal separation of fried foodstuffs from frying oil, with solids discharge from the apparatus (4) being controlled by a reciprocating bottom closure member (138), said apparatus (4) comprising: a cylindrical member (136) rotatable about a vertical axis and including a lower end and a perforated vertical side wall, said perforated vertical side wall having an inner surface, said cylindrical member (136) having an open bottom at said lower end and an interior defined by said perforated vertical side wall; a bottom closure member (138) rotatable about said vertical axis and including a lower end, a central raised portion, and an inclined side wall extending downwardly and outwardly from said central raised portion and terminating at said lower end of said bottom closure member (138), said bottom closure member (138) being movable between an upper position in which said lower end of said bottom closure member (138) is engaged with said lower end of said cylindrical member (136) and said central raised portion and said inclined side wall are positioned within said interior of said cylindrical member (136), and a lower position in which said lower end of said bottom closure member (138) is spaced apart from said lower end of said cylindrical member (136) and at least a portion of said inclined side wall is withdrawn from said interior of said cylindrical member (136); scraper means (204) for scraping fried foodstuffs accumulated on said inner surface of said perforated vertical side wall of said cylindrical member (136), said scraper means (204) being rotatable about said vertical axis, and said scraper means (204) including at least one scraping element (202) that is supported by a rib (200) and that is substantially in contact with said inner surface of said perforated vertical side wall of said cylindrical member (136); and hopper means (111) located eccentrically with respect to said vertical axis of said cylindrical member (136); wherein said scraping element (202) is (i) a linear scraping element (202) extending linearly in a direction parallel to the rotational axis of the cylindrical member (136) or (ii) a spiral scraping element, for scraping fried foodstuffs accumulated on said inner surface of said perforated vertical side wall of said cylindrical member (136). A vacuum frying chamber according to claim 1, wherein said apparatus (4) further comprises braking means for abruptly braking said cylindrical member (136). A vacuum frying chamber according to claim 1 or 2, wherein said apparatus (4) further comprises braking means for abruptly braking said bottom closure member (136).

Inventors: HATTORI RYUICHI, NAKAGAWA NOBUHIDE, HATTORI, RYUICHI, NAKAGAWA, NOBUHIDE
Applicants: HOUSE FOOD INDUSTRIAL CO, HOUSE FOOD INDUSTRIAL CO., LTD.
Application year: 1990
Main classification: B04B11
IPC codes: B04B11, B04B9, B04B3