CN213634190U

CN213634190U - Online control system for coloring tubular film for filling food

Info

Publication number: CN213634190U
Application number: CN202022827176.8U
Authority: CN
Inventors: 胡安; 阿古斯蒂·索雷特·马顿
Original assignee: Weiss Kefan Technology Suzhou Co ltd
Current assignee: Weiss Kefan Technology Suzhou Co ltd; Viscofan Technology Suzhou Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-07-06
Anticipated expiration: 2030-11-30

Abstract

The utility model relates to a be used for to filling colored on-line control system of tubulose film of food. The on-line control system for coloring a tubular film filled with a food product comprises: an optical color recognition sensor on a dry colored tubular film that is flattened and collected on a collection spool; and a sensor controller. The color hue and its uniform distribution over the entire surface of the film are continuously monitored by an optical color recognition sensor to achieve accurate color recognition.

Description

Online control system for coloring tubular film for filling food

Technical Field

The present invention relates to an on-line control system for the correct colouring applied to tubular films for filling with food products during the manufacturing process of the tubular films (casings). The color hue and its uniform distribution over the entire surface of the film are continuously monitored by an optical color recognition sensor to achieve accurate color recognition.

Background

Synthetic food casings derived from cellulose and collagen are often colored for aesthetic purposes, and in some cases to transfer color to meat. In both cases, the colors or pigments may be derived from pure substances, or alternatively, they may be the result of a mixture of two or more colorants or pigments in order to obtain the appropriate color and color scheme. The substances that constitute colorants for the food industry are mostly water-soluble, whereas pigments are water-insoluble solids, but dispersed in aqueous media or other fluid-phase vehicles (fluid-phase vehicles), which are often accompanied by substances that aid dispersion and promote their stability. From now on we will use the word "dye" or alternatively "colouring agent" to denote all substances (pure substances or mixtures) used for colouring the casing. The colorant or dye must be absorbed by or adhere to the film.

The sausage casing can be colored during the extrusion, washing and drying process, for example by dipping or spraying an aqueous colorant solution. It is also possible to apply the dye to the casing after the casing is extruded and before or after the casing is dried, but before the casing is wrinkled. The dye may be applied to the casing between the final washing step and the drying step in the casing manufacture. For example, patent US4038438A to Rahman, Teepak In 1976 provides a method for permanent colouring of synthetic food casings, wherein the tubular casing is contacted with a solution containing caramel while In the gel state and before drying for a time sufficient to impart the desired colour level to the casing, and the caramel is then cross-linked to insolubilise the caramel impregnated In the casing, thereby achieving permanent colouring of the casing. To achieve impregnation of the tubular casing in the gel state with caramel colorant, colorant is added to the plasticizing bath or, alternatively, the casing after passing through the plasticizing bath is further contacted with a separate bath containing caramel colorant. This method can result in an uneven distribution of the color on the surface of the casing.

The dye may also be sprayed onto the outer surface of the casing, or the dye may be applied to the surface of the casing with a bath after washing and then dried in a conventional manner. Dyes may also be applied to the dried casing in a similar manner prior to casing wrinkling.

However, due to, among other factors, differences in colorant absorption or different adhesion of the colorant at different points of the film, the above-described method may result in an uneven distribution of the color of the casing surface, which produces an uneven color appearance that is objectionable to consumers.

If the colorant is also transferred to the meat of the filled food product, the non-uniformity is also transferred to the meat, thereby providing an unnatural and undesirable appearance to the product.

In the practice of manufacturing colored films, it is known to monitor color characteristics by means of optical color recognition sensors. The monitoring may be performed discontinuously during the manufacturing process by sampling and analyzing the film, or may be performed on-line. During casing manufacturing, it is desirable to control properties such as film color while producing the film, and to continuously or periodically adjust process parameters to maintain desired properties of the casing produced.

In the plastics, printing, textile and paint manufacturing industry, color prediction is a working tool that allows solutions to be provided for color variations that may occur between production batches. Color matching is defined as a method for manufacturing a colored product in order to predict the final color of the material from a previously established mixture of pigments or colorants.

When various pigments are added to the base material, the color of the mixture can be predicted according to the Kubelka-Munk theory. The theory has been applied to various fields of plastics, paper, textiles and the like.

It is convenient to briefly define principles relating to optically measured properties, such as colour, opacity and reflectivity of translucent sheet materials. Opacity is a physical property of a film, such as paper, that determines the extent to which the paper will cover an object covered by it.

The diffuse reflectance of a sample is the fraction of incident monochromatic light of a given wavelength that is diffusely reflected from the sample. For each wavelength, the relationship between the incident light energy and the light energy returned from the surface of the body is the reflectance curve R ═ f (λ), which characterizes the color of the body.

Light that is not diffusely reflected in many directions but specularly reflected is referred to as specular reflectance. The sum of the specular and diffuse reflectance is called total reflectance. In general, when the human eye observes the color of an object, specular reflection of the light source is neglected. In order to measure the color of the sample seen, specular reflectance should be excluded and only diffuse reflectance measured.

Reflectivity (reflectivity) is the reflectivity (reflectivity) of a sufficiently thick stack of samples of the same material. If further increasing the thickness has no effect on the output, the stack is sufficiently thick. In the case of samples with very high opacity, the measured reflectance may be equal to the reflectance.

The method comprises predicting the colour of the opaque material from the percentage of reflectivity at each wavelength of the visible spectrum (380nm to 780nm), since this percentage is a function of the light absorbed and scattered by the pigment particles found in the substrate, which means that, for each frequency of the visible spectrum, each component of the colour formulation has an absorption coefficient K and an dispersion coefficient S; this will be given by the respective coefficients of each component multiplied by their proportion in the mixture. Specifically, when you have a thin opaque object, the relationship described by the Kubelka-Munk theory is the following equation (1):

wherein n is the number of ingredients in the mixture and w is the mass fraction thereof. To utilize this theory, it is necessary to know the values of the coefficients K and S. The relationship between these coefficients and the reflectance at each wavelength is given by the following equation (2):

this equation allows for the direct calculation of the quotient between K and S for any material from the reflectance values for each wavelength (the reflectance would be calculated as 1). Thus, if the values of K ═ f (λ) and S ═ f (λ) for all components of the material are known, then K for the group can be calculated from its composition_mAnd S_mAnd (2) and determining the inverse of each wavelength using equation (1)The refractive index. From this reflectance curve, the color coordinates of the material are calculated, so that the theory allows to estimate the color of the material from the characteristic data of its composition.

Color matching has the following advantages for the manufacturing industry, including: a) the possibility of obtaining a large number of shades with only a reduced number of pigments or combinations of colorants; and b) efficient use of the raw materials used in the production process to obtain good quality products.

An example of discontinuous monitoring can be obtained from US4769246A by Baldwin, Devro in 1987, where the collagen casing is dyed brown by using chocolate as a dye (chocolate is injected into the collagen gel during preparation) and then mixed and homogenized before extrusion and even mixed with other colorants (such as pepper oleoresin) to obtain a redder shade like "mahogany". In example 4 of the above document, a series of casing samples were prepared in which the percentage of chocolate in the dye formulation was varied, wherein the dye contained 0%, 1%, 5% and 10% chocolate. The color of the casing was measured using a MINOLTA CR-100 colorimeter and a MINOLTA DP-100 data processor.

One of the most difficult quality control issues in the film manufacturing industry is to control color, gloss, and opacity within specified ranges during film manufacturing (i.e., on-line control). The color of a white surface and its opacity greatly affect its appearance in the human eye and the intensity of any color applied to it. Color and opacity measurements are closely related, making color or reflectance measurements sensitive to changes in opacity.

Reflectivity is a fundamental property of materials and forms the basis for matching the color of translucent sheet materials, such as paper. The reflectance data is used to calculate appearance properties such as tristimulus values from the international commission on illumination (CIE) which measure the intensity of light based on three RGB primary color values, typically represented by X, Y and Z coordinates, or chromaticity coordinates. The tristimulus value system is the basis of a color language, also known as the CIE color system, for conveying accurate color values worldwide.

In samples that are not completely opaque, the measured reflectance may be a function of the presence of the background and the reflective properties. The color values calculated from these measured reflectance values may be erroneous. Furthermore, if there is an uncontrolled variation in the weight or opacity efficiency of the translucent sheet material, the error due to the background may vary uncontrollably. Artificial casings, whether made of collagen or cellulose, are generally translucent films and, even though they may be colored, their opacity is not sufficient to prevent the transmission of incident light through their parts.

One solution to the problem of color measurement or reflectance dependence on opacity is to use alternating black and white mosaic to foil the web of film and use the Kubelka-Munk formula to estimate the reflectance of an infinitely thick stack of the film. Alternatively, the film web may be backed with a plate that matches the target reflectivity. As an example of background art in the field, the De Remigis patents US3936189 and US4015904, which describe fixed optical shoe assemblies with black and white patterns on which the web is moved to measure color, opacity and brightness, should be mentioned. Similar systems are described in patents US3992100 and US4019819 to Lodzinski.

These solutions have various drawbacks, such as: a) there is a blank space between the web of color material to be measured and the optical backing surface; b) the friction of the material to be measured on the backing surface causes the material to deteriorate. However, an improved solution to this problem proposed in the prior art is to use a support roll (US5047652A (Lisnyansky 1991)) wherein the surface of the support roll is in full contact and moving at the same speed as the translucent sheet material web. According to the utility model, accurate information about the reflectivity of the translucent laminate can be obtained. In the case of certain specific applications of colorants, the colored surfaces of these films are susceptible to corrosion, for example by rubbing, when the application of the dye is carried out by impregnation or coating of the outer wall. Even when the backup roll is rotated at an angular speed such that the linear speed of its surface coincides with the advancing speed of the film, the use of the backup roll may cause corrosion on the impregnated surface of the casing.

Therefore, there is a need to develop an online color control system for thin films that avoids all of these disadvantages.

SUMMERY OF THE UTILITY MODEL

The present invention relates to an on-line control system of the correct colouring applied to tubular films for filling food products during the manufacturing process of the tubular films (casings).

The utility model relates to a be used for to filling colored on-line control system of tubulose film of food, this control system includes: an optical color recognition sensor on a dry colored tubular film that is flattened and collected on a collection spool; and a sensor controller.

Preferably, the sensor controller is at a remote location.

Preferably, the optical color recognition sensor and the sensor controller are connected by an optical fiber.

Preferably, the end of the optical color recognition sensor that recognizes the color is attached to a moving element that fixes the position of the sensor.

Preferably, the mobile element is fixed in a radial position with respect to the axis of the reel and is fixed within an arc comprised between a vertical position with respect to the position of the reel and a radial position less than pi/4 radian behind the axis of the reel.

It is an object of the present invention to provide an online control system for casing coloration which allows to record reliable values in order to correctly assess possible color changes throughout the process.

In addition, it is an object of the present invention to provide an online control system of the coloration of casings which is simple and does not require the incorporation of fastening elements, support elements or mobility elements for the correction of the reflectivity or any other type of element than those pre-established in the standardized manufacturing process.

Accordingly, it is an object of the present invention to provide a non-invasive online casing color monitoring system that reduces or eliminates variations in sheet opacity to accurately measure the color or reflectance of a translucent sheet material.

To obtain a tubular film, the process comprises pressing and/or washing and colouring and/or drying and/or creping steps.

In the utility model described below, when a colored tubular film is wound onto a reel as a partially opaque web and any point of the smooth web is itself wound onto the reel, the colored tubular film (known as "smooth casing") is considered to be an infinitely thick laminate, where the measured reflectance can be considered to be equal to the reflectance.

In the present invention, the term "smooth casing" refers to a colored tubular film that is flattened and wound onto a reel.

It is therefore characteristic to control the colouring on the smooth web wound on itself on the semi-finished material take-up reel.

The present invention therefore relates to an in-line control system for colouring tubular films filled with food products, characterized in that it comprises an optical colour recognition sensor for colour recognition on a coloured tubular film which is flat and wound on a reel or on a smooth web wound on itself in the form of a flattened tube on a drying material take-up reel.

In this way, it is not necessary to introduce optical backing elements, which represent new elements in the standard equipment of the casing production process, which require: 1) space occupation in a position before the winding system; 2) workers who maintain and clean their surfaces to remove color stains; 3) support elements, such as rollers, before and after the backing element; 4) drive components and their corresponding controllers and "encoders", switchboards, etc., all of which are also subject to revision and maintenance; 5) pressure control, etc.

Drawings

For a better understanding of what has been set forth, some drawings are attached in which the actual conditions of the embodiments are shown schematically and merely as non-limiting examples.

Fig. 1 shows a diagram of a monitoring system of the present invention.

Detailed Description

As mentioned above, the present invention relates to an on-line control system for colouring tubular films filled with food products, characterized in that it comprises an optical colour recognition sensor located on a dry coloured tubular film which is flattened and collected on a winding reel.

In fig. 1, the layout of a system for color monitoring "smooth casings" in a winding station has been schematically represented, i.e. flat and dry casings that have left the dryer and then been wound onto reels for a subsequent creping process.

In the figures, the casing (T) is advanced linearly towards a winder (B) in which it is wound, forming a laminated reel (R).

Advantageously, the controller of the optical colour recognition sensor (CS) is located in a protected remote location from which the optical signals are sent and received by means of a fibre-optic probe S, the head (H) or end of which is attached to an element (not shown) that can be translated in space and fixed in a position on the reel, so that the probe is focused in a direction always radial with respect to the axis of the reel and within an arc comprised between a vertical position and a radial position not exceeding pi/4 radians behind it, since in this way two important requirements are satisfied: 1) light beams incident on the material and coming from the sensor collect information from the areas where the diffuse reflectance is considered equal to the reflectance; and 2) the position of the sensor does not intrude into the operating space of the winding station and therefore intervention can be carried out at any time without interfering with the winding process. Using a modulated high power white LED, a point of white light is projected through an optical fiber onto the surface to be detected. A portion of the light scattered from the target is guided through the same optical fiber to a true color detector, separated into long, medium, and short wavelength light components (X long, Y medium, Z short), and converted into L a color values. The controller is easily configured through a network interface (WI) and displays the measurement results on a screen.

Thus, the sensor controller is preferably at a remote location.

Preferably, the end of the optical color recognition sensor that recognizes the color is attached to a movable element that fixes the position of the sensor. More preferably, the fixing location is radial with respect to the spool axis and is within an arc between a perpendicular position with respect to the spool position and a radial position no more than pi/4 radians behind the spool axis.

Claims

1. An on-line control system for coloring a tubular film of a filled food product, said on-line control system for coloring a tubular film of a filled food product comprising:

an optical color recognition sensor located on a dry colored tubular film that is flattened and collected on a collection spool; and

a sensor controller.

2. An in-line control system for tinting tubular films of filled food items according to claim 1 in which the sensor controller is at a remote location.

3. An in-line control system for the coloration of tubular films filled with food products according to claim 1 or 2, wherein said optical color recognition sensor and said sensor controller are connected by optical fibers.

4. An in-line control system for the coloration of tubular thin films filled with food products according to claim 1 or 2, characterized in that the end of the optical color-recognition sensor that recognizes the color is attached to a mobile element that fixes the position of the sensor.

5. An in-line control system for the coloration of tubular films filled with food products according to claim 4, wherein said mobile element is fixed in a radial position with respect to the axis of the reel and within an arc comprised between a vertical position with respect to the position of the reel and a radial position less than pi/4 radians behind the axis of the reel.