CN216815761U

CN216815761U - On-line inspection system for extrusion line of artificial casing

Info

Publication number: CN216815761U
Application number: CN202123235423.6U
Authority: CN
Inventors: 阿古斯丁·索雷特马顿; 胡安·内格里桑佩尔
Original assignee: Viscofan Technology Suzhou Co ltd
Current assignee: Viscofan Technology Suzhou Co ltd
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2022-06-24
Anticipated expiration: 2031-12-21

Abstract

An in-line inspection system for an extrusion line of artificial casing, the in-line inspection system having: at least one temperature detector comprising a thermopile including at least one thermocouple and at least one thermistor; and electronics associated with the detector and intended to wirelessly transmit the signal to the processor for collecting and processing the temperature signal.

Description

Online inspection system for extrusion line of artificial casing

Technical Field

The present invention is in the field of the manufacture of artificial casings for filling food and describes a system for on-line inspection of the casing surface using an infrared thermometer to detect the gel temperature.

Background

Temperature measuring systems using infrared thermometers are increasingly used today, because they allow the temperature measurement of an object located at a distance without making contact with the object. These sensors measure temperature in a non-contact manner by using the property that all materials are capable of emitting electromagnetic waves in the infrared range, which radiation is completely correlated with the temperature of the object. The part between 0.7 and 14 μm is most important for infrared temperature measurement, since for higher wavelengths the energy level is very low and will not be captured by the sensor. If the amount of infrared energy emitted by the object and its emissivity is known, the temperature of the object can be determined.

During the manufacture of artificial casings for filling food, by tubular extrusion of plastic masses of polymers of natural origin, such as polysaccharides and proteins, etc., the long path of the extruded tube passes through various dry and wet systems, in each of which the temperature at which the casing circulates is critical for the correct consolidation of the casing and therefore must be checked regularly. For purposes of illustration, we refer to casing consolidation as a set of tubular film transformation processes that begin with extrusion of the casing and successfully arrive at the winding station. Throughout this period we refer to the casing as a body or gel.

For the examination, those points are selected which are most representative in the case where the temperature of the gel cannot fall below or exceed a predetermined value, within a tolerance of a few degrees. The inspection is performed by using an infrared thermometer, also called pyrometer, which is based on the emission of infrared radiation generated in the body as a result of its temperature.

The check is typically performed discontinuously, although within a predetermined time period during manufacturing, in order to obtain values with a similar history. However, this is a time consuming task and is subject to regularity factors with high human factors. In addition, checkpoints are sometimes inaccessible or pose serious measurement difficulties to the operator performing the inspection. These factors subject the measurement results to certain variations, such as the distance measured with respect to the body under examination, the room temperature at which the measurement is made, the interval at which the examination is made at each point, etc.

SUMMERY OF THE UTILITY MODEL

For all the above cases, it is desirable to have a measuring system that allows continuous monitoring of the casing temperature without limiting the number of points or stations where the measurement is made, that also allows selecting the optimal points for better control of the critical phase in terms of thermal dependency, and that allows centralized monitoring from a single point without incurring unnecessary waste of time.

It is therefore an object of the present model of the utility model to provide a system for continuously checking the temperature of casings during their production, which avoids or minimizes the human factor in said checking, thereby improving the measurement accuracy, which allows checking at points inaccessible to the operator, and checking the quality and the occupational safety of the operator.

Another main object of the model of the utility model is to incorporate an improved measuring system that is able to obtain the most accurate values possible even under unfavorable conditions, such as environments with extreme temperatures.

Another main object of the model of the utility model is to devise a continuous and accurate system for measuring the temperature of the casing in multiple stations, which can be monitored from a remote concentration point to facilitate the management of the casing consolidation process.

The utility model provides an online inspection system for an artificial casing extrusion line, wherein the online inspection system comprises: at least one temperature detector comprising a thermopile comprising at least one thermocouple and at least one thermistor; electronics associated with the temperature detector and intended to wirelessly transmit a temperature signal to a processor for collection and processing of the temperature signal.

Drawings

To facilitate a better understanding of the characteristics of the utility model and to supplement the description, the following drawings are attached as an integral part of the description and are given by way of illustration and not of limitation:

FIG. 1 is a diagram of the operation of the present invention.

Fig. 2 is an example of a temperature detector suitable for use with the present invention.

Detailed Description

The thermal detector consists of a sensitive element that changes in response to the absorption of electromagnetic radiation, thereby changing the properties of the material and thus producing an electrical signal proportional to the radiation incident on the sensitive element. Thus, a thermal detector may also be defined as an electronic transducer that converts thermal energy into an electrical signal and operates on the principle that each emits Far Infrared (FIR) thermal radiation.

The casing thermal inspection system of the present invention comprises a thermopile based series of infrared thermometers (see fig. 2) wherein the thermometers are located in various fixed positions or measurement stations, e.g. at the most critical point of the production line from which the gel temperature is continuously recorded, by conduction along the casing from the moment of extrusion and until after the dryer. From each site, the thermometer communicates via a wireless connection mechanism (e.g., via Wi-Fi technology) with a central system where the information is processed and through which the temperature of each site can be controlled and recorded in real time. This therefore allows a free choice through measurement stations that can vary according to the manufacturing process and therefore does not require a representation in the current model. By combining the thermistor 2 with the thermopile 3, the temperature detector 1 is also equipped with a compensation system for room temperature, and therefore the temperature detector 1 is able to record the temperature of the body, in this case the casing in motion, in a more accurate and realistic manner. The system allows the creation of an infinite number of checkpoints, each of which generates a continuous signal that can be monitored by a central station or central point, and processed, stored and extrapolated by control software into a graph through which visual control can be performed. Thermopile-based detectors incorporating thermistors offer the advantage of compensating for room temperature and thus improve the measurement of the body to be inspected, in this case the casing gel.

The continuous control system of each point is able to signal, within a predetermined time, when the body temperature deviates from the specified temperature of the location within the tolerance value.

Thermopile construction and operation

The thermopile detector is formed by a set of thermocouples interconnected in series at the output, which produce a voltage proportional to the radiation received. The thermocouple is formed by joining two different metals, and the joined metals generate a voltage according to a temperature difference between the two metals. Each of the thermocouples is made of two different materials having opposite polarities and does not require an external source of polarization. Thermocouples are located in the hot and cold areas of thermal insulation. A cold junction is placed on the silicon substrate to dissipate heat, the junction being connected to a known reference. On the other hand, in the hot area, there is a black body that absorbs infrared radiation, raising the temperature according to such radiation. In this way, the voltage generated is proportional to the temperature difference in the thermocouple, varying by a magnitude of tens or hundreds of millivolts.

In addition to the thermocouple responsible for providing a voltage proportional to the incident radiation, the temperature detector incorporates a thermistor inside the housing (see fig. 2) in order to compensate for the room temperature at which it is located. The thermistor is a Negative Temperature Coefficient (NTC) type thermistor that is composed of a resistance of a semiconductor material and whose value decreases as the temperature increases.

The voltage V generated by the thermopile according to Stefan-Boltzmann law_tpProportional to the fourth power of the absolute temperature at which the object being measured is located, so if we consider ambient reflected radiation and the radiation of the detector itself, we find:

V_tp＝K(εT⁴ _obj+(1-ε)T⁴ _r–T⁴ _d)

where K corresponds to the constant or sensitivity of the device; the parameter ε represents the emissivity of the material being measured, where (1- ε) is the emissivity due to room temperature (T)_r) But a reflection generated on the measurement object.

Emissivity (epsilon) is the ability of an object to emit or absorb energy. Emissivity is defined as the relationship between the energy emitted by an object at a certain temperature and the energy emitted by a black body at the same temperature. The value of emissivity varies according to the material and is between 0 and 1.

Assuming that the device will always be exposed to the same room temperature as the measured object, the previous equation is simplified, obtaining the expression for the object temperature as follows:

where the constant K depends on the sensitivity of each device, the devices must be calibrated against the reference sensor.

Room temperature T_rResistance R from thermistor_thThe value of the resistance obtained varies exponentially with temperature:

R_th＝R_oe^{β(1/Tr–1/To)}

wherein R is_oIs with reference to the temperature T_oThe resistance value of the lower thermistor, the temperature being expressed in kelvin, and the parameter β being a constant related to the material from which the thermistor is made, the parameter β varying between 2000K and 6000K. These reference parameters are provided by the manufacturer, obtaining the room temperature from the previous expression as a function of the resistance value provided by the thermistor at said temperature

T_r＝[1/β·LnR_o/R_th+1/T_o]

Knowing the response of the thermistor and thermopile, we can know the temperature at which the object being measured is. First, we must know the sensitivity (K) of our device, and the emissivity (ε) of the material to be measured. With these data we start to obtain the value of the room temperature by the resistance value of the thermistor and subsequently the value of the voltage supplied by the thermopile and are therefore able to calculate a compensation value for the temperature of the object by means of equation [6 ].

A series of steps performed in order to obtain the temperature of the measured object can be represented by the flow chart shown in fig. 1, in which step the room temperature is first calculated, in order to subsequently obtain therefrom a compensated temperature of the object.

The temperature detector is developed and calibrated according to the illustrated thermopile model, which is just like the model that would be used in the device of the present invention.

The remote temperature detector used in this model must be able to do soThe operation is performed with respect to the object temperature, wherein the measured value is between e.g. 0 ℃ and 60 ℃, wherein the room temperature of the device must be in the range of e.g. 0 ℃ to 70 ℃. The distance between the measuring device and the object must be at least 15cm, the minimum effective area of the measuring object being 10 x 10mm²。

A suitable thermopile required for the device or thermometer of the present invention is a type or model HMSM21L3.0F5.5 thermopile from the manufacturer Heimann sensor [ HETE ]. This model has a built-in lens that allows us to narrow the viewing angle by about 34 degrees, and has a filter with a wavelength between 8 and 20 μm and a focal length of 3 mm.

The room temperature of the thermopile is between-20 ℃ and 120 ℃, the measurement temperature is limited between-40 ℃ and 120 ℃, and the range covers the required working range.

In view of the present description and drawings, it will be understood by those skilled in the art that the present invention has been described in terms of certain preferred embodiments of the utility model, but that numerous variations may be incorporated into the preferred embodiments without departing from the objects of the utility model as it is claimed.

Claims

1. An in-line inspection system for an extrusion line of artificial casing, characterized in that the in-line inspection system comprises:

-at least one temperature detector (1), said temperature detector (1) comprising a thermopile comprising at least one thermocouple (3) and at least one thermistor (2),

-electronics associated with the temperature detector and intended to wirelessly transmit a temperature signal to a processor for collecting and processing the temperature signal.

2. The on-line inspection system for an extrusion line of artificial casing according to claim 1, wherein the temperature signal comprises a temperature of the artificial casing and a room temperature.

3. An in-line inspection system for an extrusion line of artificial casing according to claim 1, wherein the temperature detector is located at least 15cm from the transmission line of the artificial casing in the in-line inspection system.