FIELD OF THE INVENTON The patent relates to a cuvette for analysis of liquid food products, which can be applied for analysis of various food fluids. This cuvette can be part of numerous kinds of apparatus for analysis of milk, vegetable oils or oils, extracted from biological products, or fluid food compositions, extracted as a result of applied secondary treatment. The cuvette is designed in particular to provide a thin film of the examined substance in a specific zone for a beam measuring, for example with infrared rays, where the cuvette provides and maintains the same constant temperature for numerous successive measurements, ensuring high accuracy of reading.

BACKGROUND OF THE INVENTION

Known are some solid (capsuled) cuvettes with glass or polymeric plates, other cuvettes with a complex shape or some with demountable structures, with bodies of stainless steel or of other for the food industry approved materials. All these cuvettes have a common disadvantage - they have a complex and a long piping system and a complex construction, which makes the implementation of these inventions be expensive. With such a complex construction the cuvettes cannot be accurate enough and not fast enough in the heat transfer. Another disadvantage is the consumption of great amount of the analyzed products. The way of the analyzed fluid is long and full of structure curves, which demands working under high pressure. This often leads to pipe clogging. A system, which works under pressure, must be constructed to be more complex and stable, which is more expensive to produce. The complex shape of the flow way complicates the cleaning of the apparatus and an incompetent handling can lead to pipe clogging or to permanent damages. The repair is also costly.

A method and an apparatus for analysis of fluids are known, which apparatus is made of cuvettes in a system of valves and membranes, which is build of a solid body, composed by three parts. In this body are punctured ducts, which go through the three parts. These ducts build a complex pipe system. The body encloses in its middle part, between the gasket elements two parallel transparent plates with a gap between them, which is 37 μιτι. The gap between the plates forms a chamber, where the entrance and the exit of the chamber are connected to a transport system for fluids. This system is build by punctured ducts in the body of the cuvette and by subsequent extendable external flexible conductive connections after them, made of plastic materials with a low conductivity, which serve for the passing of the measured fluid and are part of the measurement path.

The cuvette works as follow: The measured fluid sample must be first homogenized in a previous device under pressure of about 90 kg/cm ² . After the homogenization, in a membrane system, the fluid is compressed up to 4 bar, passing through a safety valve. The pressure of the fluid drops to 3 bar in the chamber and to 2 bar in the space between the transparent plates and when leaving the chamber, in the flexible pipelines. Patent application GB Nr. 2149531.

The disadvantage of this cuvette is that the fluid must flow through a very complex system of crossing ducts and connections, by a high pressure in a range of 3-4 bar. The ducts have a cut of only 2-3 mm ² and the chamber is only 37 μιη long, so that leads to periodically blockage and eventually to an exchange of the whole system. If the system was even smaller, that could increase the speed of the measured fluid, but there would be even more blockages in the system. However, one smaller and thinner system without blockages could increase the quality of the measurement. The huge diameter of the cuvette means more needed fluid for analysis and longer preparation before the measurement. This reduces the quality of the measurement and takes more time. The measurement process with the known apparatus requires preliminary treatment of the fluid - homogenization and works under pressure in the whole system. This leads to blockages and to a cooling of the measured fluid, which means a low viscosity of it and a slow and inaccurate measurement.

The task of the new invention is to create a cuvette for analysis of liquid food products with a short path of measurement up to the chamber, which works under pressure of at best 0,5 bar and allows working without blockages and without any complex pre-chambered ways, where the reducing of the pipe cuts leads to a maintaining of the measured sample in certain temperature ranges, which in turn maintains a higher viscosity during the measurement to prevent blockages. There is no preliminary preparation of the measured fluid needed. This preparation must be made on the way to the measuring chamber, which considerably shortens the measuring time.

SUMMARY OF THE INVENTION

The task of the new invention is solved by a cuvette for analysis of liquid food products, which is built by a inlet and a outlet pipes and a body between them, where the three elements are mounted in a row for an one-way flow, fixed to each other via detachable screw connection, with a possibility of pipe changing through a loosing of the connecting screws. The inlet and the outlet pipes are thin-walled and have a diameter from 0,5 mm up to 1,5 mm. The body is made of copper (Cu) or of other highly heat-conductive material and is compiled by closing caps, between them a gasket ring, where two transparent plates with a space between them are closed in, so all the parts make a whole bundle. The space between the transparent plates amounts from 50 μιη to 95 μιη, where this space builds the measuring chamber, on which entrance is mounted the inlet pipe and on which exit is mounted the outlet pipe, all in a one-way flow. Along the inlet pipe are mounted heat exchangers, which have a contact to each other. The heat exchangers are made of highly conductive material. On them and on the body are attached temperature sensors and heat elements, which are linked through a circuit board and electrical connections to a coupling.

The advantages of the cuvette for analysis of fluid food products consist in the construction, which allows the short one- way flow of the fluid, and in the small cross-section of the path, where the measured fluid flows through the pipes in the measuring chamber. At the same time the increasing of the distance between the transparent plates leads to a regularity of the flow. There is no high pressure in the system of the cuvette necessary, which could complicate the construction or the maintenance. Because of the shorter path of the analyzed sample and the lack of a preliminary preparation of the fluid the speed of the measurement increases without to reduce its quality. Furthermore there is the possibility of an easy and fast exchange of the pipes. On the one hand, the straight pipe system prevents blockages, on the other hand if blockages happen, it is not necessary to exchange the whole cuvette, but only the pipes, which are not parts of the measuring chamber as in the known devices. The choice of the material of the pipes, their thin walls and the presence of heat exchangers combined with the temperature sensors, which control the temperature on the way of the fluid compensate the long and complex ways for preparation of the analyzed fluid like in the known cuvettes, which are necessary to bring the sample in a suitable for measurement form. The choice of the material of the body and the heat-exchanger guarantee the maintaining of the optimal sample parameters. The above described invention shortens the time to the start of the measurement, and hence, positively influences the speed at which the final result and the effect of the analysis are obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

On the Fig. 1 there is a diagram of a cuvette for liquid food analysis;

EMBODIMENT OF THE INVENTION

There is a cuvette for analysis of fluid food products, which is build of an inlet pipe 1, a outlet pipe 2 and a body 3, placed between the pipes, where the three elements are mounted in a row for an one-way flow. The pipes 1 and 2 are fixed on the entrance and the exit of the body 3 through screws 14. The pipes 1 und 2 are thin-walled, made of stainless steel and a diameter of 0,6 mm. The body 3 is made of copper and contains caps 7 and 8, which close a unit, compiled of a gasket ring 4 and two transparent plates in it. The plates are made of glass and there is a space of 85 μιη between them. All of the elements of the unit build the measurement chamber 9. On the pipe 1 and in a contact with it are mounted heat-exchangers 10, made of a highly conductive material (for example copper Cu). On the heat-exchangers 10 and the body 3 are attached temperature sensors 12 and heating elements 13, which are connected to coupling 6 through a circuit board.

The cuvette works as follow: on the entrance of the cuvette (from right to left on the fig. 1) through the inlet pipe 1 flows the examined fluid. The temperature sensor 12 on the first heat- exchanger 10 reads the fluid temperature and the heating element 13 starts to work, in case this is necessary. The fluid flows forward to the other heat-exchanger 10, where in the same way the temperature is adjusted and the testes ^' fluid flows in the body 3 between the glass plates 11, which build together with the gasket ring 4 the measuring chamber 9. There, the respective sensor 12 and the heat-exchanger 10 keep the temperature constant during the measurement. After that, this sample is pushed through the outlet pipe 2 by a further sample. The sequential connection of the inlet pipe 1, the outlet pipe 2 and the body 3, the diameter of 0,6 mm of the inlet and the outlet pipe 1 and 2 and the space of 85 μηι in the measuring chamber 9 facilitate on the one hand a smooth flow, a high quality of the measurement and prevent blockages. On the other hand the short path of the measurement to the chamber (9) and the simultaneous preparation of the measured fluid increases the speed of measurement and decreases the time of measurement. The one-way flow does not requires a working pressure more than 0,5 bar, which makes the construction relatively easy, without the mandatory requirements in case of needed high pressure around 3-4 bar, a comparable high pressure for these systems, but which is needed in a complex and angled systems to make the fluid flow through.

In case of blockage or contaminations of the pipes the caps 7 and 8 can be disassembled from the body 3 through loosening of the screws 14, the glass plates 11 can be put out and cleaned. The pipes 1 and 2 can be cleaned mechanical with a small "ramrod". If this could be impossible, the pipes can be removed from the body 3 through screws 14 and can be exchanged with new ones.

USE OF THE INVENTION

The invention can be implemented for a making of an apparatus for analysis of a milk or other liquid food compositions or substances, where the measurement bases on the principle of the emission and distribution of a light beam through the analyzed fluid, which is placed in transparent plates.

Literature: Application of a patent GB No. 2149531 (Al);