JP7723883B2 - flyer - Google Patents

Description

This invention relates to a continuous fryer equipped with two net conveyors, one above the other.

In commercial fryers, applying an electric field to the oil used for frying or to the food being fried is said to have the effect of preventing the oil from deteriorating and improving the taste of processed foods.

In order to apply this technology to continuous fryers, it has been proposed to place flat electrodes for applying voltage in the gaps between the inner surfaces of each side wall of the oil vat and both the left and right sides of two upper and lower net conveyors installed inside the oil vat (Patent Document 1), or to place frame-shaped electrodes for applying voltage inside each of the upper and lower net conveyors, parallel to the respective conveyor nets (Patent Document 2).

Utility Model Registration No. 3165708

Japanese Patent Application Laid-Open No. 2001-95695

When using the former type of prior art, the electric field in the oil is concentrated between the electrode used to apply voltage and the side edges of the upper and lower net conveyors, while when using the latter type, it is concentrated between the electrode used to apply voltage and the conveyor net of each net conveyor. As a result, in either case, the necessary electric field is barely formed between the upper and lower net conveyors through which the workpieces are transported, and sufficient effectiveness cannot be expected. Furthermore, the electrodes installed inside the oil tank themselves can get in the way during cleaning operations and may impede the flow of oil within the tank.

In view of the problems with the prior art, the object of this invention is to provide a flyer that applies voltage directly to the upper conveyor, thereby eliminating the need for an electrode for applying voltage and creating a substantially uniform electric field between the upper and lower net conveyors on which the workpieces are transported.

To achieve this objective, the invention comprises an oil tank, an upper conveyor and a lower conveyor installed in two tiers, one above the other, within the oil tank, and a power supply that applies voltage to the upper conveyor. The upper and lower conveyors are net conveyors, each with an endless conductive conveyor net. The power supply uses the underside of the conveyor net of the upper conveyor as an electrode for forming an electric field, forming an electric field between the upper surface of the conveyor net of the lower conveyor, while the lower conveyor and the oil tank are grounded along with the housing of the power supply.

Furthermore, the upper and lower conveyors may be configured so that the lower and upper surfaces of each conveyor net face each other vertically.

With this invention's configuration, the power supply unit can apply voltage to the upper conveyor to form a nearly uniform electric field in the oil between the lower surface of the upper conveyor's conveyor net and the upper surface of the lower conveyor's conveyor net, which face each other from above and below, i.e., between the upper and lower net conveyors through which the workpieces are transported. This can be expected to have a favorable electric field effect on both the oil used for frying and the workpieces being fried. Furthermore, because the lower surface of the upper conveyor's conveyor net can be used as an electrode for applying voltage and forming an electric field, there is no need to install any other special electrodes in the oil tank, and there is no risk of inconvenience caused by installing electrodes in the oil tank.

By placing the upper conveyor on the frame of the lower conveyor via an insulating support material, it can be easily insulated from the lower conveyor and the oil tank in which it is installed. The support material can be any shape that allows the upper conveyor frame to be placed on the lower conveyor frame via the material, such as a long material that runs continuously in the front-to-back direction of the upper and lower conveyors, or a block material with multiple pieces distributed in the same direction.

The upper conveyor, which is combined with the lifting mechanism, can be lifted higher by the lifting mechanism as needed, which is convenient for cleaning work, for example. Furthermore, the insulating lifting device can maintain insulation between the upper conveyor and the lifting mechanism regardless of the lifting height of the upper conveyor.

If the drive motor for the upper conveyor is insulated from the upper conveyor and mounted on the frame of the upper conveyor, there is no risk of the upper conveyor's insulation being impaired even if the casing of the drive motor itself is grounded for safety reasons. In this case, the drive motor can be connected to the shaft for the upper conveyor's drive sprocket via an insulating coupling, for example, to complete the insulation from the upper conveyor.

Overall configuration schematic vertical cross-sectional view Schematic cross-sectional view corresponding to the X-X line in FIG. Overall configuration schematic side view Operation explanation diagram An explanatory diagram equivalent to FIG. 2 showing a comparative example

The following describes an embodiment of the invention with reference to the drawings.

The fryer comprises an oil tank 31, an upper conveyor 10, a lower conveyor 20, and a power supply 32 (Figs. 1 and 2). The upper conveyor 10 and lower conveyor 20 are installed in two levels, one above the other, within the oil tank 31, and the power supply 32 can apply voltage V to the upper conveyor 10 via an output cable 32a.

The oil tank 31 is a long, box-shaped container that can heat the deep-frying oil F stored inside to a predetermined temperature using a heat source such as a burner or heater (not shown). The bottom of the oil tank 31 has a gently sloping, upward slope 31a at the front.

The upper conveyor 10 is a net conveyor constructed by incorporating an endless, conductive conveyor net 12, for example made of metal, between left and right frames 11, 11 so that it can circulate. The front of the upper conveyor 10 is formed obliquely upward to match the slope 31a at the front of the oil tank 31, and the conveyor net 12 is wrapped around multiple rollers 13, 13... on front and rear shafts 13a, 13a between the frames 11, 11. Guide rollers (not shown) are provided in the middle of the upper conveyor 10.

The shaft 13a of the rollers 13, 13... at the front of the upper conveyor 10 is connected to the drive sprocket 13c via the drive chain 13b, and the shaft 13d of the drive sprocket 13c is connected to the output shaft 14a of the drive motor 14 via an insulating coupling 14b. The drive motor 14 is mounted on the frames 11, 11 of the upper conveyor 10, insulated from the upper conveyor 10 via a bracket (not shown). The drive motor 14 is a variable-speed motor controlled by a control device (not shown), and can drive the upper conveyor 10 in the direction of arrow K1 in Figure 1. The casing of the drive motor 14 is grounded for safety.

The lower conveyor 20 is a net conveyor constructed by incorporating an endless, conductive conveyor net 22, for example made of metal, between left and right frames 21, 21 so that it can circulate. The front of the lower conveyor 20 is formed obliquely upward to match the slope 31a at the front of the oil tank 31 and protrudes beyond the front end of the oil tank 31, and the conveyor net 22 is wrapped around multiple rollers 23, 23... on front and rear shafts 23a, 23a between the frames 21, 21. Guide rollers (not shown) are provided in the middle of the lower conveyor 20.

The shaft 23a of the rollers 23, 23... at the front of the lower conveyor 20 is connected via a drive chain 23b to a sprocket 24b on the output shaft 24a of a drive motor 24, which is mounted on the frames 21, 21 of the lower conveyor 20 via a bracket (not shown). The drive motor 24 is a variable-speed motor controlled by a control device (not shown), and can drive the lower conveyor 20 in the direction of arrow K2 in Figure 1. The rear of the lower conveyor 20 extends beyond the rear end of the upper conveyor 10, along the bottom surface of the oil tank 31.

The frames 21, 21 of the lower conveyor 20 are installed on the bottom of the oil tank 31. Furthermore, the frames 11, 11 of the upper conveyor 10 are installed on the frames 21, 21 of the lower conveyor 20 via insulating support members 25, 25 on the left and right, and the entire upper conveyor 10, except for the drive motor 14, is insulated from the oil tank 31 and the lower conveyor 20.

The upper conveyor 10 and lower conveyor 20 transport workpieces W, W... that are placed at the rear of the oil vat 31 via their respective upper and lower surfaces while remaining submerged in the heated oil F in the oil vat 31, allowing them to be fried before reaching the front end of the oil vat 31. The workpieces W, W... are continuously placed onto the conveyor net 22 of the lower conveyor 20 at the rear of the oil vat 31 (in the direction of arrow K in Figure 1), and are discharged to the front of the oil vat 31 via the upwardly inclined portion of the lower conveyor 20 at the front end of the oil vat 31. Note that the frames 11, 21 of the upper conveyor 10 and lower conveyor 20 are not shown in Figure 1.

The upper conveyor 10 is suspended so that it can be raised and lowered via a lifting mechanism 40 (Figures 2 and 3). However, in Figure 3, the frames 11, 21 and drive motors 14, 24 of the upper conveyor 10 and lower conveyor 20 are not shown.

The lifting mechanism 40 is composed of front, rear, left, and right wires 42, 42... that suspend the upper conveyor 10 via insulating hoisting devices 41. The upper end of each wire 42 is wound around a hoist drum 43, and each pair of front and rear hoist drums 43, 43... is fixed to a common drive shaft 43a. The front and rear drive shafts 43a, 43a are arranged to cross the upper conveyor 10 via frame frames 44, 44 with legs 44a, 44a erected on the left and right side edges of the oil tank 31, and can be rotated synchronously in both forward and reverse directions via a common variable-speed motor (not shown).

The upper conveyor 10 rotates the hoist drums 43, 43... in unison forward and backward directions via the drive shafts 43a, 43a to wind up and lower the front, rear, left, and right wires 42, 42..., thereby lifting it above the left and right support members 25, 25 while maintaining a horizontal position, and then lowering it onto the support members 25, 25. Furthermore, by connecting the frames 11, 11 of the upper conveyor 10 to the support members 25, 25 together via, for example, an engagement bracket (not shown), the lifting mechanism 40 can also raise and lower the upper conveyor 10 and lower conveyor 20 simultaneously, allowing for convenient use when cleaning the upper conveyor 10, lower conveyor 20, and oil tank 31, respectively.

The output cable 32a of the power supply unit 32 is connected to the frame 11 of the upper conveyor 10 (Figure 2). However, regardless of the illustration, the output cable 32a must have sufficient slack length to accommodate the raising and lowering movement of the upper conveyor 10, and may be capable of being disconnected from the upper conveyor 10 via a connector (not shown) if necessary.

The output specifications of the power supply 32 should preferably be within the following ranges: positive or negative DC output, or AC output with a frequency of 20 kHz or less, including commercial frequencies, with a voltage V of approximately 0.2 to 20 kV. It is also preferable that the power supply 32 incorporate a current limiting circuit that limits the output current to, for example, 5 mA or less, or a current monitoring circuit that instantly cuts off the output current if the output current increases by, for example, 5 mA or more, to prevent electric shock accidents to workers.

The fryer operates the upper conveyor 10 and lower conveyor 20 at the same speed to continuously fry the workpieces W, W.... When voltage V is applied to the upper conveyor 10 by the power supply 32, a nearly uniform electric field is formed between the underside of the conveyor net 12 of the upper conveyor 10 and the upper side of the conveyor net 22 of the lower conveyor 20, i.e., in the oil F through which the workpieces W, W... are transported (curve (1) in Figure 4). Note that the horizontal axis of Figure 4 indicates the widthwise position of the upper conveyor 10 and lower conveyor 20 in Figure 2, and the vertical axis indicates the relative value of the electric field strength between the conveyor nets 12, 22. The upper conveyor 10 is insulated from the lower conveyor 20, oil tank 31, and lifting mechanism 40, and the lower conveyor 20 and oil tank 31 are grounded, along with the casing of the drive motor 14 and the housing of the power supply 32.

Curves (2) and (3) in Figure 4 represent comparative data for cases in which voltage application electrodes P are arranged within the oil tank 31 according to Figures 5(A) and 5(B), respectively. In Figure 5(A), flat electrodes P are arranged between the left and right sides of the uninsulated upper and lower conveyors 10 and 20 and the inner surface of each sidewall of the oil tank 31, via insulating support materials 25, 25. A voltage V of the same polarity is applied to each electrode P via output cables 32a and 32a from a power supply 32. In Figure 5(B), flat electrodes P are arranged in an insulated manner within the conveyor net 22 of the lower conveyor 20, and a voltage V is applied to the electrode P via output cable 32a from the power supply 32. Note that the power supply 32 is not shown in Figures 5(A) and 5(B).

With the configuration shown in Figure 5(A), the electric field between the conveyor nets 12 and 22 is extremely concentrated at the left and right side edges of the upper conveyor 10 and lower conveyor 20 (curve (2) in Figure 4). With the configuration shown in Figure 5(B), the electric field is uniformly distributed across the width of the upper conveyor 10 and lower conveyor 20 (curve (3) in Figure 4), but its strength is only about one-fifth of that of the present invention, shown by curve (1) in the same figure. However, in Figure 4, the absolute value of the electric field strength depends on the voltage V from the power supply 32, so voltage V can be set appropriately as needed.

The approximate specifications of the upper conveyor 10 and lower conveyor 20 used to obtain curves (1) to (3) in Figure 4 are: the width of the upper and lower conveyor nets 12 and 22 is 600 mm, the distance between their upper and lower surfaces is 40 mm, and the distance between the lower surface of the conveyor net 12 and the upper surface of the conveyor net 22 is 55 mm. Furthermore, each electrode P in Figure 5(A) is a SUS430 plate measuring 15 mm vertically wide, 700 mm longitudinally long, and 1 mm thick, while the electrode P in Figure 5(B) is a SUS430 plate measuring 590 mm widthwise, 400 mm longitudinally long, and 1 mm thick on the lower conveyor 20, and is 8 mm away from the upper surface of the conveyor net 22.

In the above description, the upper conveyor 10 is insulated from the lower conveyor 20, oil tank 31, and lifting mechanism 40 via insulating support materials 25, 25, suspenders 41, 41, etc., in order to apply voltage V from the power supply 32 and operate the conveyor net 12 as an electrode for generating an electric field. Furthermore, to ground the casing of the drive motor 14 for increased safety, the drive motor 14 is insulated and mounted on the frames 11, 11, and an insulating coupling 14b is introduced. Therefore, the specific insulating support structure of the upper conveyor 10 may be further modified as desired, as long as the same operational function can be achieved.

This invention can be widely and suitably applied to large and small commercial fryers for food processing equipped with two net conveyors, one above the other.

V...Voltage 10...Upper conveyor 12...Conveyor net 20...Lower conveyor 22...Conveyor net 31...Oil tank 32...Power supply unit

Patent applicant: Asahi Sosetsu Co., Ltd.

Claims (2)

A fryer comprising an oil tank, an upper conveyor and a lower conveyor installed in two tiers, one above the other, within the oil tank, and a power supply unit that applies voltage to the upper conveyor, wherein the upper and lower conveyors are net conveyors each having an endless conductive conveyor net, and the power supply unit uses the underside of the conveyor net of the upper conveyor as an electrode for forming an electric field, forming an electric field between the lower conveyor and the upper surface of the conveyor net of the lower conveyor , while the lower conveyor and the oil tank are grounded together with the housing of the power supply unit . 2. The flyer according to claim 1 , wherein the upper and lower conveyors have upper and lower surfaces of the conveyor nets facing each other.