Method for the production of rolled foods products

A method for the production of Chinese spring rolls and other rolled food products wherein a flat pancake is deposited on a gas permeable conveyor belt and a filler substance is placed atop said pancake, wherein said pancake successively is passed above air jets directed against the underside of said pancake to fold the front portion and opposite side portions of the flat pancake over said filling substance and wherein the folded pancake together with the filler substance finally is rolled toward the rear edge of said pancake to form a roll fully enclosing said filler substance.

BACKGROUND OF THE INVENTION 
This invention relates to a method for the production of rolled food 
products comprising a filler substance and a wrap folded onto and rolled 
around said filler substance, said method comprising the steps of 
depositing a flat wrap on a support, placing a filler substance atop the 
flat wrap, folding the front portion of said wrap onto said filler 
substance, folding the opposite side portions of said wrap onto the 
partially enclosed filler substance, and finally rolling the folded wrap 
with its filler towards the rear edge of said wrap to form a roll. 
A method of this type is used for the production of e.g., raw Chinese 
spring rolls. In Chinese spring rolls, the filler substance may consist of 
sliced cabbage, minced meat and spices, and the wrap may consist of a 
substantially rectangular pancake made from flour and water. 
Such spring rolls are primarily produced by effecting the folding and the 
rolling operations manually on a table. 
An apparatus for mechanically folding and rolling the wrap around the 
filler substance has been developed, and such apparatus is constructed in 
a manner so that the front portion of the wrap and the opposite side 
portions thereof are caught by mechanical devices and successively folded 
onto the filler substance. Subsequently, the filler substance and the 
folded portions of the wrap are mechanically rolled towards the rear edge 
of the wrap. 
The prior art apparatus is rather complicated, and furthermore, the 
production rate has not been significantly increased compared to that of 
the manual production of Chinese spring rolls. 
The object of the invention is to obtain an increased production rate in 
the production of Chinese spring rolls and similar food products. 
A further object of the invention is to eliminate mechanical devices for 
the folding of the front and side portions of the wrap onto the filler 
substance. 
SUMMARY OF THE INVENTION 
The invention is based on the discovery that a flat wrap in the form of a 
newly prepared pan cake has such properties that it is not penetrated when 
its front and side portions are subjected to the influence of flowing 
media directed against its underside, but that such portions of the wrap 
are raised from the support and falls onto the filler substance. The 
invention is also based on the discovery that the folded portions of the 
pancake remain in their folded position and do not tend to return to the 
original position. 
The method of the invention is characterized in that the folding operations 
are effected with at least one flowing medium. 
Examples of such flowing media are streams of gas, e.g., air, liquid and a 
particulate material. The folding may also be effected by creating a 
vacuum above the portions of the wrap to be folded onto the filler 
substance. 
The folding operations are preferably effected with gas streams which are 
directed against the underside of the portions of the wrap to be folded 
onto the filler substance. By using such gas streams, a number of fixed 
gas orifices which are located either below the zone in which the flat 
wrap is placed on a support, or in a path through which the flat wrap is 
passed when the folding and rolling operations are carried out. 
When using the method of the invention which permits a continuous 
production of rolled food products, it is possible to produce about 9000 
Chinese spring rolls per hour whereas the production rate of a prior art 
apparatus is about 900 Chinese spring rolls per hour. Thus, the production 
rate can be increased by a factor of about 10. 
A further advantage of the method of the invention is that a number of 
Chinese spring rolls or similar products can be produced simultaneously or 
successively on a single support. Thus, several flat wraps can be placed 
side by side or longitudinally spaced on a conveyor belt, and the belt may 
be passed above or along means for effecting the above-mentioned 
functions. 
The invention also relates to an apparatus for carrying out the method 
described above. 
This apparatus comprises a support for supporting a flat wrap and a filler 
substance placed atop the flat wrap, means for successively folding the 
front portion and the opposite side portions of the wrap onto the filler 
substance and means for rolling the folded wrap with its filler substance 
towards the rear edge of said wrap. The apparatus of the invention is 
characterized in that the means for successively folding the front and 
opposite side portions of the wrap comprises means for generating a 
superatmospheric pressure below said portions or means for generating a 
vacuum above said portions or combinations thereof. 
In a particularly preferred embodiment of the apparatus of the invention 
the support comprises an endless horizontally located gas permeable 
conveyor belt, orifices for temporarily generating gas streams directed 
upwardly, and located below the upper run of said conveyor belt so as to 
fold the front portion of the wrap onto the filler substance and orifices 
located at both sides of the conveyor belt to generate gas streams 
directed upwardly so as to fold the opposite side portions of the wrap 
onto the filler substance. 
The apparatus preferably also comprises a compressing means which is 
located above the upper run of the conveyor belt and at such a distance 
from the upper run that it produces a rolling of the partially folded wrap 
and its filler substance over about 270.degree. before the opposite side 
portions are folded onto the filler substance. 
The final rolling of the folded wrap and the filler substance is preferably 
effected by a second compression means located above the upper run of the 
conveyor belt. 
In order to obtain predetermined fold lines when folding the opposite side 
portions of the wrap onto the filler substance, folding rods are 
preferably provided adjacent to the upper run of the conveyor belt and on 
both sides of the center line of the belt, said folding rods extending 
parallel with the center line or forming an acute angle with said center 
line of the conveyor belt. 
When the wrap is contacted with said folding rods, the latter ensure that 
only that portion of the wrap which is located outside the zone between 
said rods is folded onto the filler substance.

BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 shows a preferred embodiment of the apparatus of the invention in a 
schematic plan view and illustrating a wrap and a filler substance located 
thereon in four progressive positions; and 
FIG. 2 shows a vertical section to the apparatus illustrated in FIG. 1 
taken along the line II--II. 
The apparatus shown comprises an endless conveyor belt 1 having an upper 
run passing above a support 2, and supported at the ends by two rollers 3 
of which one is driven by a gear 4 and a motor 5. A further roller 6 is 
located below the support 2, said roller 6 also being in contact with the 
conveyor belt 1. Four cross beams 7, 8, 9 and 10 extend transversely of 
the conveyor belt 1, and one of these cross beams 7 supports a plate 11 
which is pivotably mounted in a hinged joint 11'. The second cross beam 8 
supports two folding rods 12 extending longitudinally of the belt 1. The 
cross beam 9 also supports two folding rods 13 which form an acute angle 
with the center line of the belt 1. 
The cross beam 10 supports a plate 15 which is pivotly mounted by means of 
a hinged joint 14. 
The operation of the apparatus shown is as follows: 
At the inlet end of the apparatus, a flat wrap 16 is placed on the belt 1. 
A filler substance 17, e.g., in the form of a frozen body, is placed on 
top of the wrap 16 at the front edge of said wrap. During the passage of 
the conveyor belt along the support 2, the front edge of the wrap 16 
passes above an orifice 18 from which a stream of air temporarily is 
directed upwardly. This stream of air causes the front edge of the wrap 16 
to fold onto the filler substance 17. During the passage below the plate 
11 which exerts a predetermined pressure on the body comprising the 
partially folded wrap and the filler substance, said body is caused to 
roll. Subsequently, the body thus obtained passes below the cross beam 8 
where the folding rods 12 compress the wrap close to the ends of the 
filler substance 17. Subsequently, the side portions of the wrap 16 passes 
above two orifices 19 generating air streams which are directed upwardly 
and below two orifaces 21 creating partial vacuums both of which cause the 
side portions of the wrap to fold onto the filler substance 17, the 
folding rods 13 defining the folding lines. The orifaces 19 and 21 may be 
used either in combination or separately. 
The body thus obtained is then passed below the pivotably mounted plate 15 
and by contacting said plate it is subjected to a further rolling so as to 
form a final roll 20 in which the filler substance 17 is completely 
enclosed in the wrap 16.