Device for heating brewing mash

Disclosed is a device described for heating brewing mash, and a heat source and a heat exchanger that transfers heat with it and that has mash flowing through it are provided. The heat exchanger exhibits at least one evenly coiled tube that has a smooth surface on the inner side. The spelts contained in the brewing mash continuously repolish the inner surface of the tube so that the danger of deposits and overheating of brewing mash components is reduced.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
In beer production, which can be broken down into malting, wort preparation 
and fermentation, it is necessary in an intermediate process step to bring 
the mash, i.e., crushed malt mixed with brewing water, in a controlled way 
to a predetermined temperature and to keep it there for a certain period 
to decompose the remaining starch into sugar and dextrin. In doing so--as 
in the entire field of food chemistry processes--it is important to 
arrange the heating so that delicate substances are not influenced to the 
detriment of taste. But on the other hand, even with such processes, 
attention is to be paid to the aspect of economic efficiency, i.e., a 
so-called external heating system for brewing mash must be able to perform 
the heating process in a relatively short time. 
2. Discussion of the Background 
For this purpose, devices are already known in which a tube bundle heat 
exchanger is used as a heat exchanger. Such heat exchangers are in fact 
very efficient and a matching of the heat transfer output to the process 
in each case can very easily be performed over the surface of the tube 
bundle. But it has turned out that such known devices worked qualitatively 
at a high level only in a very narrow operating range near an optimal heat 
output and a mash flow rate matched to it. But the application diversity 
of known devices was greatly limited so that the invention is based on the 
object of providing a device for heating brewing mash, i.e., an external 
heating system for mash designed to provide, in a greatly expanded 
operating spectrum, i.e., in a broadened range of heat output and flow 
rate, on the one hand, an economical and, on the other hand as careful as 
possible a heating of the brewing mash. 
SUMMARY OF THE INVENTION 
This object is achieved by the features given in the characterizing part of 
claim 1. 
According to the invention, the brewing mash is pumped through at least one 
evenly coiled, for example spiral, bent tube that is heated by a heating 
medium. Since in this way no flow cross section changes result in the flow 
path of the brewing mash, an uncontrolled formation of turbulence in the 
flow channel is counteracted so that no uncontrolled overheating of mash 
components can occur. The smooth inner surface according to the invention 
of the tube also precludes microturbulences in the wall area of the tube 
so that even with direct application of a flame to the tube, baking on of 
mash parts is precluded. Even with a high specific heat transfer between a 
heating medium and brewing mash, the danger of taste-changing reactions of 
the brewing mash is reduced to a minimum. In doing so it has turned out 
that the spelts contained in the brewing mash, when flowing through at 
least the one tube, continuously take care of repolishing the inner 
surface so that deposits on the inner side of the tube and the subsequent 
start of overheating the mash components can systematically be precluded. 
It is obvious that increasing the flow rate through the heat exchanger 
according to the invention changes nothing with respect to the effects 
explained above, so that the device according to the invention is equally 
suited for breweries with widely varying production volumes. It is even 
possible to work with only a single, suitably coiled tube, since by 
coiling the tube on the one hand the heat exchange distance is lengthened 
and, on the other hand, the heat transfer coefficient at the tube walls 
can be raised especially by intensive contact between the spelts and the 
tube walls. But because of the increased heat exchange distance, moroever, 
the further advantage results that even with the greatest heat output the 
temperature increase per unit path can be kept smaller than is the case 
with conventional devices, so that a qualitatively higher quality heating 
of the brewing mash can be achieved. 
Advantageous further developments of the invention are the object of the 
subclaims. 
With the further development according to claim 2, at least the one tube 
can very conveniently be placed in a heating chamber. Further, the flow 
through the tube receives a swirl that improves the heat transfer by 
which, additionally because of the thus increased rubbing effect of the 
spelts, the self-polishing effect is reinforced for the inner walls of the 
tube. 
The heat exchanger tube can be in heat exchange contact with a heating 
medium in various ways. Since no cross section changes are necessary in 
the path of the brewing mash from a reservoir to the heat exchanger and 
from the latter on the return to the reservoir, no heat expansions of 
parts need be taken into consideration in the heat exchange path, as was 
the case in the prior art, opening the possibility of leading at least one 
coiled tube directly through a combustion chamber and acting with a 
heating flame there. 
Of course it is also possible to lead at least one tube according to claim 
4 through a separate heating chamber that is flushed by a suitable heating 
medium, such as for example a heating gas or a vapor stream. 
With the further development according to claim 5, the formation of 
deposits on the inner wall of the tube is counteracted at the outset, by 
which the rubbing effect of the spelts can extend from the startup of the 
device to the entire inner surface area of the tube. The operating 
reliability of the device is additionally increased this way. 
With the further development according to claim 7, the heat output can 
additionally be matched to the production system present in each case. 
Of course the design according to the invention of the device is not set 
for any particular conveyance of the brewing mash flow relative to the 
flow of the heating medium. But it has proven advantageous to convey the 
brewing mash either countercurrent or cocurrent to the flow of the heating 
medium. 
With the further development according to claim 10, there results a more 
even introduction of the heating warmth into the tube, by which the danger 
of localized overheating is additionally reduced. 
Since, as already indicated above, the flow relationships inside the tube 
are qualitatively changed only slightly even with greatly varying flow 
rates, the device can advantageously be equipped according to claim 11 
with a control device that continuously controls the flow rate of the 
brewing mash depending on the instantaneous temperature increase per time 
unit. 
Other advantageous embodiments are the object of the remaining subclaims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, reference symbol 2 denotes an external heating system for 
brewing mash, i.e., a device with which the brewing mash can be brought to 
a certain process temperature according to a predetermined heating 
pattern. This heating device exhibits a housing 4, which, for example, has 
a cylindrical shape. Air inlet openings 6 are made on the bottom side of 
the housing and on the top side a hot air outlet tube 8 is provided. 
Housing 4 encloses a heating chamber 10 below which a burner 12, for 
example a gas or oil burner, is provided. The walls of housing 4 are 
protected by a shield 14 from excessive temperature effect. 
Through heating chamber 10 there is led a tube coil in the form of a 
spirally coiled tube 16 that is led out of heating chamber 10 by straight 
sections 162, 164. In these areas there are connections 166 and 168 for 
suitable feeding or discharging. 
Coiled tube 16 is made of a polished tube that is seamless on the inside 
and that consists preferably of stainless steel. The brewing mash to be 
treated, which is drawn out of an intermediate container by a pump not 
shown in more detail in FIG. 1, is pumped through tube 16 so that it is 
fed in through section 162 and removed through section 164. In flowing 
through the tube spiral, heat is fed to the brewing mash first by burner 
flames 18 and, with increasing path distance, by the heated hot air. The 
temperature difference of the brewing mash in sections 162 and 164 can be 
controlled or adjusted by the flow rate and the output of burner 12. It 
has turned out that the spelts contained in the brewing mash, even at 
reduced flow rates, cause a continuous self-polishing effect by which 
deposits on the inner side of the tube spiral and thus overheating of 
brewing mash components can be prevented. It can be seen from the drawing 
that no cross section changes occur in the flow path of the brewing mash 
so that the flow profile, even with drastic changes in the flow rate, 
remains constant, by which turbulences in the heating area and localized 
overheating caused by them are eliminated. In this way a very gentle and 
very easily controllable heating of the brewing mash to the desired 
temperature is made possible. Further, the lengthened heat transfer 
distance, even with the highest burner outputs, results in a reduced 
temperature gradient relative to the unit path, by which the danger of 
overheating can additionally be reduced. 
FIG. 2 shows the same device for heating brewing mash as in FIG. 1. For 
this reason the components of the device are designated with identical 
reference symbols. The only difference from the embodiment according to 
FIG. 1 is the flow direction of tube spiral 16, so that a countercurrent 
heat exchanger is provided. 
FIG. 3 shows a preferred control device for the device for heating brewing 
mash shown in FIG. 1. Since the device itself is designed identically to 
the one according to FIG. 1, a more detailed description of this device 
can be dispensed with. Again, identical reference symbols are used for 
comparable elements. 
Brewing mash from an intermediate container 24 is fed to section 162 by a 
feeder pipe 20 with the aid of a preferably adjustable pump 22. The heated 
brewing mash is fed back from section 164 to intermediate container 24 by 
a return pipe 26. 
Burner 12 has a heating agent feed pipe 28, in which a regulating valve 33 
is incorporated. 
Reference number 32 designates a central control unit to which are fed 
signals of a temperature measuring point 34 in return pipe 26 and of 
another temperature measuring point 36 for the temperature of the brewing 
mash in intermediate container 24. By a computer provided in central 
control unit 32, an appropriate control signal is given by a control line 
38 to a control device of pump 22 and/or a control device 40 of regulating 
valve 30. For this purpose, there can be incorporated in the control line 
a suitable logic unit 42, with which the control of pump 22 or regulating 
valve 30 can additionally be influenced. This regulation principle is 
suitable for two- or three-stage gas or oil burners. But still more exact 
temperature profiles can be achieved if continuously adjustable burners 
are used. Preferably the computer provided in the control unit is in a 
position to detect also the heating rate of the brewing mash to preclude 
overheating of the brewing mash in good time. 
Of course the invention is not limited to the concrete embodiments 
described above. Thus it is possible for example that instead of direct 
contact of burner flame 18 with tube spiral 16, a design is used in which 
the tube spiral is placed in a heating chamber flushed by hot air and/or 
hot vapor. 
Variations with respect to the number, position and size of the tubes 
conveying the brewing mash are also possible. One possible variant 
consists in that, according to FIG. 4, two tube spirals 46 and 48 are 
arranged inside a heating chamber 50, which again has a shield for the 
housing walls not shown in more detail. The flow of the heating medium is 
denoted by arrow 52. The arrows varying in size on the right side of FIG. 
4 indicate the mass throughputs, varying in size, through both tube 
spirals 46 and 48. Arrows 56 are to indicate the division of the heat flow 
inside heating chamber 50, which assures an even heating on all sides of 
tube spirals 46 and 48. 
Another variant of the arrangement with several tube spirals is shown in 
FIG. 5. Here there are two tube spirals 66 and 68 next to each other in a 
common heating chamber 70. Also in this embodiment there occurs a 
branching of the heating medium stream into the different areas of heating 
chamber 70, so that an intensive and as even a heating as possible of tube 
spirals 66 and 68 occurs. 
The invention is not limited either to the tube consisting of a tube 
polished on the inner side. Rather, suitable coatings can also be provided 
that can continuously be repolished by the effect of the spelts carried 
along in the brewing mash. 
The invention thus provides a device for heating brewing mash and a heat 
source and a heat exchanger transferring heat with it and having mash 
flowing through it are provided. The heat exchanger exhibits at least an 
evenly coiled tube that has a smooth surface on the inner side. By the 
spelts contained in the brewing mash, the inner surface of the tube is 
continuously repolished, so that the danger of deposits and overheating of 
the brewing mash components is reduced.