GB2210551A - Peeling machine - Google Patents

Abstract

The machine for peeling onions or similar peel fruits (e.g. pineapples) or vegetables, includes a rapidly rotating spinner shaft 1 and a conveyor shaft 2 carrying a helical screw 6. The shafts together define a channel 7 along which onions are conveyed by the screw 6 supported by both shafts. The onions are fed down an inlet chute to enter the channel 7 at one end. As the onions travel along the channel they are spun by the shaft 1. At the other end of the channel 7 a slot-shaped nozzle 20 connected to a blower 25 directs a jet of air between the shafts 1, 2 to remove the skins from the onions. The onions leave via an exit chute whilst the skins pass between the shafts 1, 2 to a funnel 28. Cutter blades 18 are rotated above the inlet chute to nick the skins of tough skinned onions. <IMAGE>

Description

PEELING MACHINE This invention relates to machines for peeling onions or other fruits or vegetables such as pineapples or scallions which can be peeled in similar manner.

In an existing machine which originates in Japan and is described in UK Patent Specification No. 2 151 129A, onions are fed one-by-one to a pair of rotating drums which support and spin the onion whilst it otherwise remains stationary. After a predetermined period of time a blast of compressed air is directed onto the spinning onion to remove its skin, and the drums then move apart allowing the peeled onion to drop through.

Since the onions are only peeled one at a time this machine has a very low peeling rate.

UK Patent Specification No. 1 393 990 describes an onion peeling machine comprising a pair of parallel rotate hafts for supporting the onions, w3th a stop plate located above one of the shafts and a number of water sprays located above the other shaft spaced along its length. A conveyor carrying a series of spaced fingers moves the onions progressively along the shafts through the water sprays to remove their skins.

Although this machine has a higher handling rate than the Japanese machine, it is of relatively complex construction and because of the relative disposition of the shafts, the stop plate and the sprays, the machaine can only handle onions within a restricted size range.

One aim of the present invention is to provide a form of peeling machine which is of relatively simple construction and is therefore easy to maintain, and is capable of handling a range of sizes without modification.

The present invention provides a machine for peeling onions or other fruits or vegetables capable of being peeled in similar manner, comprising a pair of rotatably driven shafts mounted side-by-side with substantially parallel axes to support the onions, feed means for feeding top and tailed onions to an input end of the shafts, discharge means for collecting and conveying peeled onions away from an opposite outlet end of the shafts, and fluid outlet means disposed above the shafts for directing a jet of fluid onto the onions to remove their skins, in which one of the shafts consitutes a conveyor shaft and carries a helical screw for conveying the onions along the shafts from the input end to the outlet end, and the other shaft constitutes a spinner shaft for spinning the onions as they travel along the shafts.

The spinner shaft will normally rotate at several times the speed of the conveyor shaft, and though not essential, the shafts preferably rotate in the same direction.

The height of the fluid outlet means is preferably adjustable relative to the shafts to permit adjustment of the jet intensity. Although water jets could be used, the fluid outlet means preferably constitutes an air outlet. A drawback of the Japanese machine is that its power consumption is heavy due mainly to the compressor required to provide a short burst of air to the air outlet before the drums move apart. Although the present machine could be driven by a compressor, in preference the machine includes blower means for providing a continuous supply of air to the air outlet.

The use of a blower instead of a compressor can reduce the energy consumption of the machine by as much as two thirds. The outlet is preferably slot shaped for optimum peeling. The outlet is preferably dosposed adjacent to the outlet end of the shafts to ensure that the onions attain their full rotational speed before being peeled.

The invention will now be exemplified in the following description to be read in conjunction with the accompanying drawings in which: Figure 1 is a side view of an onion peeling machine in accordance with the invention, Figure 2 is a plan view of the machine, and Figure 3 is an end view of the machine looking from the right in Fig.s 1 and 2.

The machine comprises a pair of shafts 1, 2 rotatably journalled in bearings 3, 4 respectively (Fig. 2), which are in turn mounted on a frame 5. The first shaft 1 constitutes a spinner shaft having a knurled surface, but it could also be smooth or rubber-coated.

The other shaft 2 consitutes a conveyor device and carries a helical screw 6 in the form of a radially projecting blade which extends along substantially the entire length of the shaft. The two shafts are mounted on substantially parallel axes, side-by-side, with the outer periphery of the screw 6 almost, but not quite, touching the spinner shaft 2. The shafts together form a channel 7 in which an onion can be supported by the two shafts.

The shafts are each rotatably driven from a respective variable speed motor 8, 9 (e.g. an electric or petrol driven motor) via a belt and pulley, chain and sprocket or similar drive system 10, 11.

At one end of the channel 7 (the left hand end as shown) a chute 12 is mounted on the frame 5 to feed top and tailed onions (i.e. onions having their tdps and root ends sliced off) one after another to the shafts via a conveyor 14 from a hopper or other suitable supply (not shown). The chute 12 is downwardly inclined towards the shafts and its lower end is provided with a U-shaped guard 15 (Fig. 1) to direct the onions into the left hand end of the channel 7. An air driven vibrator 16 is mounted on the underside of the chute to assist movement of the onions along the chute. Aii air driven motor 17 is also mounted oil the underside of the chute to drive a set of rotating circular blades 18 (e.g. four) mounted on a common axis disposed transverse to the chute. The blades are arranged such that they project an adjustable distance above the floor of the chute.

Towards the right hand end of the channel 7 a nozzle 20 (Fig.s 1 and 3) is mounted by a sliding clamp 21 on a pole 22 which is upstanding from the frame 5. The nozzle is directed downwardly through the gap between the shafts. The opening of the nozzle is slot-shaped and aligned with the axes of the shafts 1, 2, although the nozzle could also be inclined at an acute angle to the axes of the shafts. The nozzle is connected by a suitable wide bore flexible pipe 24 to an air blower 25 (Fig. 3) for supplying a continuous air jet through the nozzle 20.

At the right hand end of the channel (see Fig.s 1 and 2), an outlet chute 26 is mounted on frame 5 to collect the onions as they drop off the ends of the shafts and convey them away, firstly by chute 26 and then by a conveyor 27, for further handling.

A funnel 28 (Fig.s 1 and 3) is arranged beneath the shafts to collect onion skins removed by the machine.

The skins are then carried away to waste by a further conveyor 29.

In use, the shafts are set to rotate at speeds of typically 700 rpm for the spinner shaft and 130 rpm for the conveyor shaft. Both shafts rotate in the same direction A (Fig. 3). Contra-rotating shafts may also be used but this would ter.d to cause the onions to jump around in the channel. Top and tailed onions are fed along the vibrating chute 12 to the shafts 1, 2 where they arrive in random orientations. The distance by which the blades 18 project above the chute floor is adjusted to nick the outer skins of the onions as they pass along the chute, to make removal of the skins easier. The baldes may not be necessary for some kinds of onion, paiticularly those with thin skins. The onions are then conveyed along the channel 7 by the screw 5 supported by both shafts 1 and 2. As the onions travel along the region of channel 7 between the chute 12 and the nozzle 20 the rotation of shaft 1 causes the onions to spin. The onions initially spin slowly about random axes but as they travel along the channel their rotational speed increases and they eventually come to rotate about a natural axis of rotation which, if the onion is perfectly symmetrical, is coincident with its axis of symmetry. When an onion reaches the nozzle 20 the air jet blows its skin off.

The loose skins are blown through the gap between the shafts into the funnel 28 but the onion continues to the end of the shafts and thence to the outlet chute 26 and conveyor 27.

Although the machine is capable of handling a range of onion sizes for any particular setting, the speeds of the shafts can be independently adjusted to values most appropriate for a particular batch of onions to ensure thorough peeling without removing too many layers from their skins. In the same way, the height, and thus the jet intensity, of the nozzle can be adjusted by sliding clamp 21 along pole 22. In addition, the conveyor shaft 2 can be replaced with one of different shaft and/or scz;; diamcter and pitch to suit different sizes of onion. Thus, the machine can easily be adapted for peeling onions from shallot size up to spanish onion size and with cifferent thicknesses and toughness of skin. The spacing betwen the shafts could also be made adjustable if desired.

The hopper 28 and conveyor 29 could be replaced with a chute along which the onion skins are blown by the jet from nozzle 20. The slot-shaped nozzle could also be replaced with a row of individual jet openings.

In addition to low operating cost and high throughput the machine is also low maintenance and easy to clean.

Claims (11)

1. A machine for peeling onions or other fruits or vegetables capable of being peeled in similar manner, comprising a pair of rotatably driven shafts mounted side-by-side with substantially parallel axes to support the onions, feed means for feeding top and tailed onions to an input end of the shafts, discharge means for collecting and conveying peeled onions away from an opposite outlet end of the shafts, and fluid outlet means disposed above the shafts for directing a jet of fluid onto the onions to remove their skins, in which one of the shafts consitutes a conveyor shaft and carries a helical screw for conveying the onions along the shafts from the input end to the outlet end, and the other shaft constitutes a spinner shaft for spinning the onions as they travel along the shafts.

2. A machine according to Claim 1, in which the spinner shaft is arranged to rotate at a faster speed than the conveyor shaft.

3. A machine according to Claim 1 or 2, in which the height of the fluid outlet means is adjustable relative to the shafts.

4. A machine according to Claim 1, 2 or 3, in which the fluid outlet means constitutes an air outlet.

5. A machine according to Claim 4, including blower means for providing a continuous supply of air to the air outlet.

6. A machine according to any preceding claim, in which the fluid outlet means is slot shaped and is is generally parallel with the axes of the shafts.

7. A machine according to Claim 6, in which the fluid outlet means is disposed adjacent to the outlet end of the shafts.

8. A machine according to any preceding claim, in which the feed means comprises at least one rctatable blade for cutting through the outer skin of the onions.

9. A machine according to Claim 8, in which the blade or blades project an adjustable distance from a surface over which the onions travel.

10. A machine according to any preceding Claim, in which the feed means comprises a chute coupled to a vibrator device.

11. An onion peeling machine which is substantially as described with reference to the drawings.