Arrangement and plant for fluid jet cutting of food products

An arrangement for fluid jet cutting, especially for food products, comprises a nozzle which is movable on a frame. The arrangement includes an angled pipe, one end of which is fixedly connected to and in fluid communication with one end of a hollow shaft of a reversible rotary motor. The other end of the hollow shaft is connected by means of a rotary coupling to a conduit for cutting fluid. The other end of the pipe is connected to the nozzle. A plant for fluid jet cutting, especially for food products comprises a belt conveyor for carrying the products, a device for analyzing quality and/or quantity characteristics of the products to be cut, and a device for controlling the operation of the fluid jet arrangement for cutting the products on the conveyor in response to commands from the analyzing device.

The present invention relates to a plant for fluid jet cutting of food 
products, comprising a belt conveyor for carrying the products, at least 
one arrangement comprising a nozzle which is movable on a frame for 
producing a fluid jet, a device for analysing quality and/or quantity 
characteristics of the products to be cut, and a device for controlling 
the operation of the fluid jet arrangement for cutting the products on the 
conveyor in response to commands from the analysing device. The invention 
also relates to an arrangement for fluid jet cutting. 
Such an arrangement and such a plant are disclosed in U.S. Pat. No. 
4,962,568. 
One drawback of this prior-art arrangement and plant is associated with the 
fluid jet cutting assembly. This comprises a rail which extends transverse 
to the direction of travel of the conveyor, being a conveyor belt, and on 
which runs a carriage provided with a spray nozzle. The spray nozzle 
projects from a slot provided in a housing for the assembly. The carriage 
is driven by a piston and cylinder unit. By this arrangement, the assembly 
will be exposed to heavy soiling, occasioned by water rebounding from the 
conveyor belt and entraining particles from the products that are being 
cut or have been cut earlier. This soiled water penetrates through the 
slot of the housing, which thus has to be dismounted for cleaning the 
assembly. Furthermore, there is a risk of leakage from the piston 
cylinders which may cause soiling of the food products. 
U.S. Pat. No. 4,847,954 discloses a fluid jet cutting arrangement having a 
nozzle suspended in articulated fashion from a frame disposed beside a 
conveyor. The conveyor moves relative to the nozzle frame, but during the 
cutting of a product located on the conveyor, either the conveyor or the 
nozzle frame appear to be stationary. 
U.S. Pat. No 5,133,687 discloses an automatic butchering system where the 
nozzle of the fluid jet cutting arrangement is suspended from a complex 
articulated-arm system. 
Moreover, the known fluid jet arrangements are quite complicated. 
The object of the invention is to overcome the above-mentioned problems. 
This object has been achieved by means of an arrangement and a plant having 
the features recited in the characterising clauses of the appended claims. 
Since the fluid jet arrangement is of rotational type, the housing of the 
arrangement can be provided with a simple lead-in opening for the spray 
arm, which can easily be sealed by means of a gasket. Thus, the housing 
need not be dismounted when the plant is to be cleaned, and the sensitive, 
movable components accommodated therein will remain protected and sealed 
in the housing during both the operating phase and the cleaning phase. The 
central bearing for mounting the fluid-jet conducting arm means that the 
number of parts of the fluid jet cutting arrangement that are located in 
the area of the plant exposed to cutting fluid can be minimised. 
The circular-arc movement pattern for the fluid jet nozzle enables cutting 
the products carried on the conveyor, while this too is in motion, and 
producing cuts, almost perpendicular to the direction of movement of the 
conveyor, in the products thereon, which means an increase in production 
as compared with the prior art. This is achieved by the nozzle-carrying 
arm, during part of its pivotal motion over the conveyor belt, being 
capable of moving in the same direction as the conveyor. 
The circular-arc motion of the nozzle also allows the creation of such 
cutting patterns as a translatory movement of the conveyor belt or of the 
nozzle transversely of the belt does not permit. 
It is further evident that the invention provides an uncomplicated fluid 
jet cutting arrangement. It does no longer suffer from the necessity of a 
vast number of components, such as toothed belts, gears, piston and 
cylinder units with air/fluid supply hoses, lubricant, seals and joints. 
In the fluid jet cutting arrangement of the invention, only one arm with 
its nozzle need be moved. Also, these components may be very lightweight, 
which contributes to high acceleration ability and, hence, increased 
production capacity. 
The rotary arrangement also means quicker acceleration of the jet nozzle to 
the desired cutting places and, hence, achievement of more acute corners 
upon directional changes in the cutting pattern, with a consequent 
reduction of product waste and an increased production rate.

Over a belt conveyor 1 for carrying food products, in this case chicken 
breasts, there are arranged a number (in this case four) stationary water 
jet assemblies 2 for cutting chicken breasts B in two trimmed segments of 
fillets. The water jet assemblies 2 are arranged in a row vertically above 
the longitudinal centre line of the belt 1 (FIG. 2). They comprise a 
rotary motor 3 of reversible type, whose shaft 4 is fixedly connected to 
an arm 5, making an angle with the shaft. The shaft 4 and the arm 5 
consist of pipe sections serving to supply water from a source of water to 
a spray nozzle 6 fixed on the free end of the arm 5. The upper end of the 
shaft 4 is connected to a conduit 5a from the source of water by means of 
a rotary coupling 5b. The lower end of the shaft 4 is supported in a 
liquidproof stationary housing 7 for the motor 3 by means of a ball 
bearing (not shown). The lead-in opening for the shaft 4 in the housing 7 
is sealed by means of a gasket 5c. 
The arrangement further comprises a device for determining quality/quantity 
parameters of the chicken breast. These parameters control the operation 
of the water jet assemblies 2 (the motors 3 thereof) to provide the 
trimmed segments or fillets, via a computer. Such a device may be of the 
type described in U.S. Pat. No. 4,962,568. It includes a video camera 8 
positioned to "see" the food products on the conveyor belt 1, and a light 
source for illuminating the food products with a light line so as to 
produce a shadow line on the product. The video camera 8 views this shadow 
line and converts shadow line information into electrical signals 
representing the width, length and thickness dimensions of the product. 
The signals are processed in a computer 9 in accordance with a 
predetermined program, the computer controlling the operation of the water 
jet assemblies 2 to provide cutting motions for cutting the product into 
segments of desired weight/volume/profile. 
Alternatively or as a complement to the above-mentioned shadow line 
analysis, the technique according to U.S. Pat. No. 4,631,413 (to which the 
applicant is a licensee) can be used for controlling the operation of the 
cutting jet assemblies 2 to cut the products into segments of the desired 
profile. This technique is based on fluorescensce analysis of food 
products, such as fish and meat products, for determining the content of 
fat, bone, cartilage and connective tissue. 
The cutting pattern shown in the drawing can be achieved e.g. by means of 
the last-mentioned technique. The back ridge a, the fat portions b and c 
and the cartilage portions d have their characteristic fluorescence which 
therefore is usable for controlling the operation of the fluid jet cutting 
assemblies to cut off these portions to obtain the desired segments e. 
The cutting operations may be performed as follows, reference being made to 
FIGS. 1 and 2. A chicken breast B transported on the conveyor belt 1 in 
the direction of the arrow A passes in turn through cutting stations I-IV, 
where the fluid jet cutting assemblies 2 are activated by the computer 9 
to provide the cuts S1-S4 by the motors 3 swinging the arms 5 with the 
nozzles 6 transversely (arrow C) of the conveyor 1, and by varying the 
speed of the pivotal motion (the speed of the belt 1 is constant). Thus, 
the cut S1 along one side of the back ridge a is made in station I, and 
the cut S2 along the other side of the back ridge a is made in station II, 
whereupon in stations III and IV the cuts S3 and S4 separate the segments 
e from the breast pieces b-d. 
The nozzles 6 are fixed on the respective arms 5 at a suitable angle to 
obtain the desired, clean cuts through the chicken breast B.