WO2003013253A1

WO2003013253A1 - Dough forming apparatus

Info

Publication number: WO2003013253A1
Application number: PCT/EP2001/009085
Authority: WO
Inventors: Bernardo Concetta
Original assignee: Bernardo Concetta
Priority date: 2001-08-07
Filing date: 2001-08-07
Publication date: 2003-02-20

Abstract

The invention relates to a dough forming apparatus comprising at least a couple of first and second rollers forming a nip therebetween through which the dough to be formed passes and whereby the thickness of the dough is reduced, said apparatus further comprising support means for said rollers, the support means of at least one of said first and second rollers being adapted to rotate about an axis, said axis being orthogonal to at least one of the longitudinal axes of said first and second rollers, whereby an uniform thickness on the whole width of the sheeted dough is reached and package, quality control and economic problems are improved.

Description

DOUGH FORMING APPARATUS

The invention relates to a dough forming apparatus.

There are known in the art apparatuses for dough forming, said apparatuses having

couples of rollers forming a nip therebetween, whereby the number of couples can

vary from one in a simple non-professional machine for making dough at home to

more couples of rollers in series the one after the other in professional or industrial

apparatuses, whereby a stepped reduction of thickness is obtained in a continuous

feeded mass of dough after passing each couple of rollers in the reduction path.

After the sheeting the continuously sheeted dough is cut in sheets by cutting means.

However said apparatuses have drawbacks, an important one being the deformation

of the rollers of said couples due to the resistance of the dough material being

worked. This deformation leads to an uneven thickness of the continuously sheeted

dough, said thickness being generally speaking more than the requested value in a

center zone of the nip between the rollers of the reduction couple and less than the

requested value in a zone near to the supports of the rollers. Due to the uneven

thickness therefore the final product, e.g. crackers or biscuits in the preparation of

which said apparatuses are normally used, would exhibit a different weight and

dimensions per product unit, leading to package, quality control and economic

problems.

After sheeting the continuous mass of dough is cut in sheets by cutter means arranged

transversely on the working line. A known way to ob viate to said drawback is to arrange after the cutting section a

second reduction line of couples of rollers, said line being substantially rotated of 90

degrees with regard to the first line. In this way what was the central zone of the

continuous sheeted dough in the first line becomes a zone in a cut dough sheet which

extends on the whole length of the nip between the rollers of the second lines,

whereby a requested thickness can be obtained on the whole width of the dough

sheet.

This solution is not however satisfactory due to the cost of providing said second line

of couples of rollers and to the deformation problem which is yet present, however

not so massive as in the first line.

The present invention as defined in the appended claims does not require said second

reduction line and minimises the roller deformation, providing therefore an

efficacious and economic solution to the above problem.

List of drawings

Figure 1 shows a prior art apparatus;

Figure 2 shows dimensions and bending deformations in the prior art rollers;

Figure 3 shows a front view of an apparatus according to the invention;

Figure 4 shows a plan view of an apparatus according to the invention;

Figure 5 shows a diagram acting force/direction in an apparatus according to the

invention.

By referring also to the above drawings a detailed description of al least one preferred

embodiment will be made as follows:

Figure 1 relates to a prior art dough forming apparatus, said apparatus comprising

couples (1, 2, 3) of rollers (4, 5) defining a nip (n) therebetween, said couples being

positioned the one after the other in a linear reduction path, said apparatus comprising

moreover cutting means for cutting the continuous fed dough (6) in dough sheets and

a second reduction line comprising further couples of rollers defining a nip

therebetween, said further couples being positioned the one after the other in a second

linear reduction path, said second path forming an angle of substantially 90 degrees

with the first path, said cutting means and second line being not shown in the

drawings.

Per se known frame, energizing, supporting and nip adjusting means for the rollers,

feeding means for feeding a continuous mass of dough to the first couple of rollers of the first reduction path, fransferring means between the first and second path and

transport means for transporting the continuous dough mass and the dough in sheets

between the couples of the rollers of the first and second path respectively are also

present, although not described in the figures.

It is known in the art that the reduction ratio of a couple of rollers, said ratio being

defined as the ratio "thickness before reduction/thickhness after reduction", should be

below 5 in order to obtain a smooth flow pattern of the dough material, as it is

requested e.g. for crackers and biscuits; a ratio between 5 and 7 is critical and a ratio

of over 7 leads to mixing of the dough material due to backflow of the dough in the

nip, whereby e.g. a layered structure as e.g. in puff pastry dough would be badly

damaged. In other occasions however a mixing can be desiderable, depending on the

type of worked dough.

In the described prior art apparatus said ratio is 3, as usual in the biscuits and crackers

industry.

The rollers are made of e.g. polished stainless steel or other known suitable material,

whereby the dough does not stick and hygienic standards of the food industry are

respected.

Figure 2 relates to the bending deformation of one of the couples of rollers in the first

reduction path.

The thickness is more than the requested value in a center zone of the nip between the

rollers of the reduction couple and less than the requested value in a zone near to the

supports of the rollers. Due to the vicinity of the supports however, the bending deformation in the support

zone is very less important than that in the center zone, so that it can be neglected. In

the following only the bending deformation in the center zone of the nip will be

considered. As visible in figure 2, where the dimensional scale is not coherent, i.e.

some dimensions have been exaggerated or reduced in order to give a better

understanding, a couple of steel rollers wherein each roller is 1.5 meter long having a

nip with a set value of 27 mm exhibits during sheeting a value of the nip in the center

of 30 mm, i.e. about 1.1 times, i.e. about 110% of the set value; this means that the

difference between real value and set value is 3 mm, about 10% of the set value,

whereby the bending deformation (f) of one roller in the center position is f = 3mm/2

=1.5 mm.

This leads therefore to a final product having weight variations in the order of 10%,

according to whether it origins from the central of from the lateral zones of the nip.

In figures 3, 4 an example of an apparatus according to the invention is shown, said

apparatus comprising in a reduction path a couple of first (7) and second rollers (8)

made of e.g. stainless steel and 1.5 meter long, said rollers forming a nip (n)

therebetween through which the dough to be formed passes and whereby the

thickness of the dough is reduced, said apparatus further comprising support means

(9, 10) in the form of e.g. ball bearings for said rollers (7, 8), each of said support

means (9, 10) of said first and second rollers being slidably mounted in parallel

planar circular guides (not shown) provided of angular references and rigidly

connected to the frame of the apparatus, whereby the support means (9, 10) are rotatable about an axis (a) passing through the center of the circles individuated by

the circular guides and orthogonal to the parallel planes containing said guides, said

axis (a) being therefore orthogonal to the longitudinal axes (b), (c) of the rollers.

In this way an axis offset regarding the longitudinal axes (b), (c) is reached, i.e. said

axes, and therefore the rollers, can be put to form an angle between them.

It should be understood that also one circular guide is sufficient, i.e. that only one

roller is rotatable about said axis (a).

By putting the axes of the rollers at an angle the force exerted by the dough on the

rollers and viceversa decreases starting from said axis (a) in a direction (d) lying in a

plane parallel to the parallel planes containing the axes (b), (c) and comprised in the

angle formed by said axes (b), (c) (figures 4, 5), whereby the thickness in the zones

near to the rollers supports increase.

In this way the negative effect of the bending deformation of the rollers on the center

zone value of the nip and therefore on the dough thickness is counteracted, i.e. the

center zone value of the nip, which as discussed above is also in this example of the

invention 110% of the set nip value, is taken as new set nip value, and the angle at

which the axes of the rollers are put is selected such that it allows an increase of the

thickness in the zone near to the supports of the rollers from said about 100% to the

110% of the old set nip value, whereby an uniform thickness on the whole width of

the sheeted dough is reached. In the apparatus of the example of the invention the thickness variations measured on

the width of the rollers are maintained in a variation band of 1 to 2%, instead of the

10% of the known state of the art apparatus.

The angle to which the axes are to be put can greatly vary, due to their dependence on

e.g the nip value, the type of worked dough, the physical properties e.g. rigidness of

the material of the rollers. Generally speaking high forces exerted between dough and

rollers and small values of the nip may request angles in the order of 0 to 15 degrees

depending also on the dough type, while large nips and reduced interacting forces

may request larger angles.

The circular slidably mounted support means are manually operated by an operator,

which modifies the angle by e.g. half a degree a time so as to approach an uniform

thickness on the whole width of the worked dough.

Per se known frame, energizing and nip adjusting means for the rollers, feeding

means for feeding a continuous mass of dough to the couple of rollers of the

reduction path, transport means for transporting the continuous dough mass before

and after the thickness reduction in the nip between the rollers are also present in the

apparatus of the example of the invention, although not described in the figure.

In advantageous manner the apparatus of the invention can be provided with an

automatic support adjusting system in the form of a closed loop automatic control

system provided with suitable software, said system comprising a thickness sensor

device as e.g. an optical, laser, acoustic e.g. ultrasonic, mechanical sensor as known

in the measuring field., said sensor being operable to measure the center zone thickness value and a near-to-the-roller-support zone thickness value and to send a

center zone thickness value-related signal and a near-to-the-roller-support zone

thickness value-related signal to a control unit provided of a suitable closed loop

retroaction software, where said signals from the sensor are confronted by said closed

loop retroaction software and from where in accord with the transfer function of the

closed loop, which is calculated in a theoretical manner known to those skilled in the

art according to the essential parameters of the physical components of the controlled

apparatus or in practical manner by a trial-and-error method, a further signal is sent to

e.g. a step motor which acts on the slidably rotatable support means in order to rotate

them to an angle whereby an uniform thickness on the whole width of the sheeted

dough is reached.

It should be understood that e.g. two independent thickness sensors can be used, one

for the center zone thickness value and a further one for the near-to-the- roller-

support zone thickness value.

The provision of a closed loop automatic control system eliminates therefore the

necessity of the presence of a dedicated operator.

Having described one possible embodiment, further modifications are to be

encompassed within the scope of the invention as defined in the appended claims.

Claims

1. A dough forming apparatus comprising at least one couple of first and second

rollers forming a nip therebetween through which the dough to be formed

passes and whereby the thickness of the dough is reduced, said apparatus

further comprising support means for each of said rollers, the support means of

at least one of said first and second rollers being adapted to rotate about an

axis, said axis being orthogonal to at least one of the longitudinal axes of said

first and second rollers, whereby said longitudinal axes and therefore said first

and second rollers can be put to form an angle between them.

2. A dough forming apparatus according to claim 1, where at least one of said

support means is slidably accomodated in a planar circular guide.

3. A dough forming apparatus according to the preceding claims further

comprising a closed loop automatic control system operable to control the

rotation of the support means,

4. A dough forming apparatus according to claim 3 further comprising at least

one thickness sensor, preferably an optical, laser, mechanical or acoustic

sensor, said sensor operable to measure the center zone thickness value and a

near-to-the- roller-support zone thickness value and to provide a center zone thickness value-related signal and a near-to-the-roller-support-zone thickness

value-related signal to a control unit provided of a suitable closed loop

retroaction software, said central unit operable to provide a further signal to the

rotatable support means in order to rotate them to an angle whereby an uniform

thickness on the whole width of the sheeted dough is reached.

5. A dough forming apparatus according to claim 4 comprising at least two

independent thickness sensors, one for the center zone thickness value and a

further one for the near-to-the- roller-support zone thickness value.

6. A dough forming apparatus according to claims 3-5 comprising at least one

step motor adapted to rotate the rotatable support means in response to said

further signal from the control unit in order to rotate them to an angle whereby

an uniform thickness on the whole width of the sheeted dough is reached.

7. Dough forming production lines comprising one or more apparatuses according

to claims 1-6.

8. Method for dough forming comprising the use of an apparatus according to

claims 1-6 or of a production line according to claim 7.