Method and apparatus for producing skinless sausages

A device and a method for producing skinless sausages by the use of molds are disclosed. The molds comprise individual hollow tubes which are open at both ends. The molds are detachably supported on conveying means and conveyed to a filling device where they are filled with sausage meat. The molds are next brought to a heating device where the sausage meat is heated until the surface is coagulated. The sausage meat at the open ends is allowed to develop freely. The molds are then conveyed to an extraction device where the sausages are extracted from the molds and transported for further treatment. The molds are, in turn, cleaned and returned to the filling device. By means of the use of molds comprising individual tubes which are detachably supported on the conveying means, great flexibility is assured in the process and in the configuration of the machine.

BACKGROUND OF THE INVENTION 
The present invention relates to a device and a method for producing 
skinless sausages by the use of molds or forms into which the sausage meat 
is introduced. 
Various methods and machines for the manufacture of skinless sausages are 
already known. In one such method, described in West German Provisional 
Pat. No. 1,226,866 and U.S. Pat. No. 2,623,451, the sausage meat is first 
filled into sausage casings, smoked and boiled, and thereupon the sausage 
casing is removed. While the disadvantage of the tough sausage casing 
which is undesirable for eating is eliminated by this method, the other 
disadvantages still remain, namely the cost of producing the sausage 
casing, the halts in production due to the limited length of the casing, 
and the interruptions because of accidential "burstings" of the casing. In 
addition to this, there is a further expense for equipment and time for 
the subsequent removal of the sausage casing. 
Other known methods operate without such auxiliary sausage casings. Thus, 
from West German Provisional Pat. No. 1,267,526 it is known to push the 
sausage meat continuously into or through a forming device in which the 
meat is coagulated in whole or in part under the action of heat. At the 
end of the forming device the sausage strand is divided by a cutting 
apparatus into individual sausages. Due to the required heating time, it 
is necessary, in order to achieve an economical rate, that the device for 
producing the sausage be of very large dimensions. Furthermore, upon 
pushing the sausage meat through the casing, undesirable changes in the 
meat take place. Furthermore, cutting the previously coagulated sausage 
strand into individual sections of sausage having straight ends results in 
a product which is not popular with the consumers. 
In another method known from West German Unexamined Application for Patent 
No. 28 39 772, "skinless" sausages are produced by applying onto the 
sausage meat a binding agent in order to form an artificial skin. Such 
sausages, however, do not actually fall within the type with which this 
invention is concerned. 
At an early data, attempts were made to fill the sausage meat into molds 
and retain them in the molds at least until the coagulation step. In one 
older method of this type pursuant to U.S. Pat. No. 1,009,953, a hollow 
cylindrical mold is filled with sausage meat and then sealed at both ends. 
The mold is then placed for a short time in a hot-water bath so that the 
outer layer of the sausage can coagulate. The mold is then opened and the 
skinless sausage ejected. This is a method for purely manual production of 
sausage. The method is very expensive and not suitable for mass 
production. 
For the industrial production of skinless sausages in larger numbers by 
means of molds, a machine in accordance with U.S. Pat. No. 1,925,157, for 
instance, is more suitable. This machine has a molding or forming device 
which is provided with a plurality of casings arranged in fixed positions. 
In order to produce the sausage, the forming device is closed at one end 
and then connected to a filling apparatus. The sausage meat is pushed 
simultaneously into all the casings thereby producing raw sausages with 
compacted meat. The forming device is then disconnected from the filling 
apparatus and opened so that the preformed sausages can be ejected and 
treated further. 
Another similar method using a molding device is known from West German 
Unexamined Application for Patent No. 25 23 506. A plurality of elongated 
casings are linked close together to form an endless chain. The casings 
are provided with removable end closures in order to impart the desired 
roundness to the ends of the sausages. Furthermore, the casings also have 
removable caps for the closing of the inlet openings. The casings fastened 
to the chain are conducted past various treatment stations which contain 
the following means: 
means for filling the molds with sausage meat; means for applying the end 
enclosures; means for applying the caps to the closures; means for cooking 
and boiling the sausages in the casings; means for removing the caps and 
closures; means for removing the cooked or boiled sausages from the molds. 
The molds with their caps and closures are expensive and the method of 
production is costly. 
In U.S. Pat. No. 994,714 a plurality of casings are fastened in radial 
groups to a wheel, the axes of the tubes being aligned parallel to the 
axis of the wheel. Upon the stepwise rotation of the wheel, the casings 
arrive at different stations. In this case also, the sausage which has 
been introduced into the casings is boiled within the casings. For this 
purpose, the lower part of the vertically arranged wheel dips into a bath 
of hot water. The casings employed are closed at both ends. 
The machine in accordance with U.S. Pat. No. 2,897,745 is of a type similar 
to that of U.S. Pat. No. 994,714. The casings are fastened vertically on a 
horizontal turntable and are heated electrically after filling. For 
cooking, the casings are closed, the closure pins being pressed under 
spring action against the ends of the casings. In this way, a uniform 
constant pressing of the meat is obtained. 
All the known methods and machines for the production of skinless sausages 
which use molds or forms into which the sausage meat is introduced have 
various disadvantages. Since the molds are arranged in special mold 
devices, the machines together with the treatment stations must be adapted 
to these mold devices, which leads to a complicated and expensive 
construction. The dimensions of the mold devices are set for a given type 
of sausage and the size of the sausage, as a rule, cannot be easily 
changed. The rate of production is also substantially determined by the 
configuration of the machine. Furthermore, it is not possible to replace 
readily the individual molds in order to produce other types of sausage. 
Summarizing, it may be stated that the flexibility and degree of freedom 
of the known methods and machines are very limited. 
The object of the present invention is to provide a method for the 
production of skinless sausages which avoids these disadvantages. By means 
of the present invention, it will be possible to produce the sausages in a 
practical and simple manner, with maximum flexibility in the handling of 
the molds. 
SUMMARY OF THE INVENTION 
In order to achieve this purpose, a device for producing skinless sausages 
is provided, comprising a plurality of individual molds, said molds 
comprising hollow tubes or tube lengths open at at least one end, 
conveying means to convey said molds sequentially along a predetermined 
path, said molds detachably supported on said conveying means, filling 
means to introduce sausage meat into said mold, heating means to coagulate 
the surface of said sausage meat, and extraction means to extract said 
coagulated sausage from said molds. A method for producing skinless 
sausages is also provided comprising introducing sausage meat into 
individual molds, said molds comprising hollow tubes or tube lengths open 
at at least one end, heating the molds until the surface of said sausage 
meat is coagulated, allowing the sausage meat at the open end to develop 
freely, and extracting the coagulated sausages from the molds. 
The individual tubes or tube lengths may be handled in various manners so 
that great flexibility in the course of the process and in the machine 
configuration is present. It is possible both to transport the tube 
lengths continuously in a closed circuit or to stack them in intermediate 
storage for batchwise operation.

DETAILED DESCRIPTION 
The apparatus for the production of skinless sausages shown in FIG. 6 has a 
filling station 1 into which the sausage meat 2 is fed by a conveyor 
device, not shown in detail. From the filling station 1, the sausage meat 
passes to the actual sausage producing machine 3 which comprises the 
following components: a filling device 4, an extraction device 5, a 
cleaning device 6, and an endless conveyor device 7 for transporting the 
filled molds 8 through the heating zone 9 and for returning the empty 
molds from the cleaning device to the filling station. Behind the machine 
there is arranged a smoking, boiling and cooling device 10 to which a 
packing device 11 is connected. 
The molds are constructed as straight or bent tube lengths 8 and 8a as 
shown in FIG. 7. These tube lengths are advantageously made of solid 
material. The selection of the material depends on the source of heat in 
which the tube lengths together with the meat mix are heated. If the tube 
lengths pass, for instance, through a microwave tunnel they must consist 
of glass or plastic, while if heated by thermal conduction, for instance, 
they should advantageously consist of metal. The tube lengths are open at 
both ends and require neither closures, caps, lids or the like. They are 
handled individually and loosely, which permits them to be used with a 
great variety of machines. It is also readily possible, if necessary, to 
replace the straight tube lengths 8 by the curved tube lengths 8a. 
In filling tube lengths 8, the meat 2 is not simply pushed into the tube 
length from the front as in the case of other known methods. Rather it is 
introduced commencing at the far end with a special filling tube 12 and 
piston 13, into the tube lengths (FIG. 8). 
After filling the tube lengths 8 with the meat mixture 2, the tube lengths 
are conducted by the conveyor belt 7 to the source of heat 9 and exposed 
there to the heat whereby the meat is at least partially coagulated. The 
tube lengths are not closed at their ends when being exposed to the heat. 
As a result of the heating, particularly of the gaseous components 
contained in the meat mixture, the meat mixture expands towards the ends. 
Due to the contact of the surface of the meat against the inner wall of 
the tube lengths, and due to the partial coagulation which has already 
taken place on the surface of the meat, a natural rounding of the end 
surfaces 14 of the resultant sausages is obtained. These sausages thus 
have a natural shape and meet the expectations of the consumer. 
The heating can be so extensive that the entire contents of the tube length 
coagulate. However, in order to attain a high rate of production and to 
limit the number of tube lengths to a minimum, it is advisable to keep the 
heating time as brief as possible. It is therefore sufficient for merely 
the outermost layer of the meat mix to coagulate since then the form of 
the sausage becomes established. Thus, for instance, by heating in a water 
bath at a temperature of 80.degree. C., the meat mixture is shaped into a 
sausage and can be ejected from the tube length after only 30 seconds 
without danger of losing its shape in the further course of treatment. 
The ejection of the sausage 15 from the tube length 8 can be effected 
mechanically or by gas pressure or the like. The ejected sausages 15 are 
transported further, for instance to the smoking, boiling, cooling and 
packing stations, while the tube lengths are readied and returned to be 
filled again. 
It is advisable to provide the tube lengths 8 with a protective coating on 
their inner surface in order to avoid any adherence of the sausage meat 
thereto. The tube lengths can be wetted with a suitable liquid before they 
are filled or they can also be provided with an anti-adherence coating. In 
addition to round tube lengths, tubes of triangular, rectangular, ovoid or 
other cross sections could also be provided. 
The actual sausage manufacturing machine 3 will now be described in further 
detail with reference to FIGS. 1 to 5. The tube lengths 8 are fed by the 
conveyor belt 7 over the fixing ramp 18 to the filling device 4. The drive 
is effected by means of a ratchet wheel 19 and a compressed air cylinder 
20 which acts on the latter. After the feeding has been effected, the 
solenoid valve 21 is actuated by a limit switch (not shown) arranged at 
the end of the stroke of the compressed air cylinder. This is done in a 
manner so that the inside 22 of the cylinder above the holding-down device 
24 is provided with compressed air and the piston 23 presses the 
holding-down device 24 against the tube length 8 and fixes the latter in 
position. The piston rod 17 of the holding-down piston 23 bears at its end 
a projection 25 which acts on a limit switch 26. The latter actuates the 
valve 27 in such a manner that the piston of the cylinder 28 for the 
feeding of the meat drives the filling tube 12 into the tube length 8. As 
soon as the piston is present, the switch 29 is actuated by the projection 
30 which is seated on the piston rod 31. 
The air in the tube length 8, which is displaced through use of the filling 
tube 12 provided with a packing 32, escapes through the slot 33 at the 
opposite end of the tube length 8. The switch 29 controls the valves 27 
and 34 and the slide 35. The latter is supported on a guide bar 36 and is 
moved by the piston rod 31. 
The compressed air fed by the pulse valve 34 to the control cylinder 37 
presses the sealing surface 39 of the closure piston 38 against the tube 
length 8 and closes off the air slot 33. The slide 35 now opens the 
flexible conduit 41 which is connected with the meat delivery pump 40. 
Since the valve 27 is actuated simultaneously with the switch 29, the 
piston rod 31 of the cylinder 28 pulls the filling tube 12 back and the 
meat 2 flows, due to the excess pressure, into the tube length 8. The meat 
conveyor pump 40 (FIG. 6) holds the meat 2 at a constant pressure. By 
actuation of the switch 42 upon the return stroke, the slide 35 is closed 
and the injection of the meat stops. At the same time, the valves 21 and 
34 are switched. In this way, pistons 23 and 38 are pushed back by the 
springs 43 and 44, respectively. 
The switch 45 which is actuated upon the pushing back of piston 23 causes 
the cylinder 20 to operate via a valve and the cylinder advances the 
conveyor belt 7 by a distance equivalent to the next tube length and 
begins a new cycle. The filled tube lengths 8 are immersed with the 
conveyor belt 7 into a liquid 46 which is heated by the heater 47 and held 
at constant temperature by thermostat control. The tube lengths are held 
on the conveyor belt 7 in the track by means of the guide 48. 
After passage through the bath, the tube lengths are brought to the 
ejection device 5 where the coagulated sausage 15 is ejected by the 
cylinder 49 (FIG. 4) which operates in synchronization with the cylinder 
28. The ram 16 effects the ejection. The ejected sausage 15 passes by 
means of another conveyor belt 50 into the smoking chamber 10 for further 
treatment. 
Preparing the tube lengths at the following preparation stations takes 
place in a manner similar to that which takes place in the filling station 
and by means of an identical control. The empty tube is rinsed with hot 
water in the cleaning device 6 by means of the nozzle 51. The waste water 
discharges via the sewer 52. In a further step, the residual water can be 
blown out with a similar nozzle. The tube lengths are now ready to be 
filled again. 
The method of producing skinless sausages which has been described above 
and the apparatus for carrying out this method have many advantages: 
The individual tube lengths are very simple parts which can be manufactured 
in a practical and economical fashion. 
These tube lengths can be used with all machines which are designed for the 
handling of removable tube lengths. 
The replacement of some or all of the tube lengths can be done readily at 
any time. 
The tube lengths are easy to handle. For example, the individual tubes are 
easily handled when being coated with an anti-adherence coating, or when 
the coating is renewed, particularly when the coating is cured. 
By the use of individual tube lengths, the designer is assured great 
freedom in the arrangement of the individual components of the machine. 
These components can be designed in a modular system and combined with 
each other in different manners. 
The use of individual tube lengths is particularly suitable for high-output 
machines with high operating rate. In the same way as in bottle-filling 
machines which can handle individually 50,000 or more bottles per hour, 
the tube lengths can also be handled individually in large numbers. 
In addition to continuous operation in a closed circuit, batchwise storage 
operation is also possible. Thus, for instance, a magazine for the 
stacking of the tube lengths can be arranged in front of the filling 
station. Upon the completion of treatment or the detachment of the tube 
lengths, all tube lengths can be arranged in the magazine. The "storage" 
principle permits the shutting down of individual working stations without 
having to stop the entire plant. 
In another plant (not shown in detail) for the production of skinless 
sausages in large numbers, a continuously rotating filling drum can be 
provided as a filling station. The tube lengths are distributed uniformly 
about the circumference of the drum and held, pneumatically or 
hydraulically, parallel to the axis of the drum. 
After the tube lengths are filled, they are transferred to a conveyor 
device which conducts them, through a microwave oven, for heating. At the 
other end of the conveyor device there is an extraction and cleaning drum 
which removes the filled tube lengths. After the ejection of the sausages 
by rams, the cleaned tube lengths are transported back again to the 
filling drum. 
In another system which is a combination of the two preceding ones, several 
units for operation (for instance, meat filling tubes) are arranged on a 
carriage which accompanies the continuously driven tube length conveyor 
device to carry out its operation (for instance, filling the tube lengths) 
and returns to its initial position after its job is complete. Despite 
stepwise operation, this system results in a continuous high-output 
production.