WO2003013254A1

WO2003013254A1 - Dough forming apparatus

Info

Publication number: WO2003013254A1
Application number: PCT/EP2001/009086
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 and comprising support means for said rollers said rollers being accomodated in said support means by shaft members extending from said rollers, each of said shaft members comprising at least a first portion extending through and a second portion extending outside said support means, said apparatus further comprising at least a force-generating means adapted to exert a force on at least one of said second portions of said shafts, whereby a roller bending force acting on the roller due to the resistance of the worked dough forced through the nip is counteracted, the roller bending deformation is reduced 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 obviate 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 deformation in the prior art rollers;

Figure 3 shows a front view of 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) defming 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

reduction line not being 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, transferring 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 figure.

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. 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 figure 3 an example of an apparatus according to the invention is shown,

said apparatus comprising a couple of first and second rollers (4, 5) made of polished stainless steel forming a nip (n) therebetween through which

the dough to be formed passes and whereby the thickness of the dough is

reduced and support means (6, 7) for said rollers (3, 4), said rollers (3, 4)

being rotatably accomodated by means of e.g. roll bearings in said support

means (6, 7) by shaft members (8, 9) made in one and extending from said

rollers, each of said shaft members (8, 9) comprising at least a first portion

(10) extending through and a second portion (11) extending outside said

support means (6, 7), said apparatus further comprising four force-

generating means in form of air cylinders (12), said cylinders being

connected in known way to said second portion (11) of said rollers so that,

when operated by a pressurised air circuit (not shown), said cylinders (12)

exert a force on said second portions (11) of said shafts (8, 9) , whereby a

roller bending force acting on the roller due to the resistance of the worked

dough forced through the nip is counteracted and the roller bending

deformation is reduced, said apparatus further comprising per se known

and not described in the drawings frame, energizing, supporting and nip

adjusting means for the rollers, cutting means after the reduction path,

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

rollers of the reduction path, and transport means for transporting the continuous dough mass through the reduction path and the dough in sheets

after the cutting means.

The cylinders are manually operated by an operator, which modifies the

pressure in the air circuit so as to approach the center zone value of the nip

to the value set by the nip adjusting means.

In order to give a value of the bending deformation reduction, in an

apparatus according to the invention having the dimensions of the

described state of the art apparatus the bending deformation (f) of one

roller can be reduced from 1.5 to 0.25 mm, i.e. seven times less than in the

known apparatus, whereby the variations in dimensions and therefore

weight of the final product are in the order of 1.5 to 2% instead that of 10%

of the known apparatus.

It is to be understood that in the present invention instead of air cylinders

hydraulic cylinders or similar equivalent force-generating members can be

used.

In advantageous manner the apparatus of the invention can be provided

with an automatic roller deformation adjusting system in the form of a

closed loop automatic control system provided with suitable software, said

system comprising at least one thickness sensor device as e.g. an optical,

laser-operated, mechanical or acoustic, e.g. ultrasonic sensor as known in the measuring field., said sensor being operable to measure the center zone

nip value and to send a center zone nip value-related signal to a control

unit provided of a suitable closed loop retroaction software, where said

signal from the sensor is confronted with a set value 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 the controlled force-generating

means, in the case of the air cylinders e.g. to the pressurising means, e.g.

the air compressor or the pressurised air storage of the air circuit, to

increase the air pressure in the cylinders whereby a greater force is exerted

on the second portion of the roller shafts and the bending deformation of

the rollers is reduced.

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. 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 and comprising support means for said rollers, said rollers

being accomodated in said support means by shaft members

extending from said rollers, each of said shaft members comprising

at least a first portion extending through and a second portion

extending outside said support means, said apparatus further

comprising at least one force-generating means adapted to exert a

force on at least one of said second portions of said shafts, whereby a

roller bending force acting on the roller due to the resistance of the

worked dough forced through the nip is counteracted and the roller

bending deformation is reduced.

Dough forming apparatus according to claim 1 further comprising a

closed loop automatic control system operable to control said force-

generating means in order to reduce the difference between a set nip

value and a measured center zone nip value.

3. Dough forming apparatus according to claim 2 further comprising at

least one thickness sensor, preferably an optical, laser, mechanical;

acoustic e.g. ultrasonic sensor, said sensor operable to provide a

signal related to the measure of a center zone nip value, a control unit

provided of a suitable closed loop retroaction software operable to

provide a second signal, the force generating means being operable

in response to said second signal from said central unit order to

reduce the difference between a set nip value and a measured center

zone nip value.

4. Dough forming production line comprising one or more apparatuses

according to one of the precedent claims.

5. Method for dough forming comprising the use of an apparatus

according to claims 1-3 or of a production line according to claim 4.