DD278057A1 - SENSOR FOR LEVEL CONTROL OF LIQUID CONTAINERS, ESPECIALLY SAUSAGE BOILING BOILERS - Google Patents

Abstract

The invention relates to a sensor for level control of Fluessigkeitsbehaeltern, especially sausage boilers, which allows the same mechanical feed, is not affected by the fat-water mixture in its function and allows hygienic cleaning. According to the invention, the object is achieved in that in a pipe socket on an inner side of the container double wall flush with a disc is arranged with a sunken Sensorflaeche that two Staebe on the Sensorflaeche heat-conducting and are arranged directed in the pipe socket and that at the first Staebe an electrical Heating resistor and the second Staebe a temperature sensor is arranged thermally coupled. A particularly advantageous embodiment according to the invention is characterized in that a control circuit of the electrical heating resistor, including the heating of the sensor is arranged by external heat sources to avoid destruction of the sensor not covered by liquid by overheating. Fig. 4

Description

For this 3 pages drawings

Field of application of the invention

The sensor for the level control of liquid nitsbehältern ^1, in particular of sausage cooking kettles is preferably used in Wurstgarprozessen and other cooking processes in Fleischvorarbeitungsbetrieben. Furthermore, the sensor for level control in emulsions, such. B. mayonnaise, cinsotzbar.

Characteristic of the known state of the art

In cooking kettles for the production of cooked sausage, as with all cooking kettles, dry running must be avoided. This is achieved by securing a level minimum e '. This must also be adhered to in order to secure the technological conditions of the cooking process. Due to the fat content, sight glasses or tubes are not applicable. Furthermore, a hygienic cleaning is not or only very labor intensive feasible.

Also Füllstanclskontrollvorrichtungen based on conductivity measurements can not be used, since the electrodes are isolated by the Fettbestandteüe.

The cooking vessels are fed by means of a hoist. The products to be cooked are housed in drawer basket inserts. Touching the cooking vessel wall through the wire basket inserts during loading is unavoidable.

The DD-WP 222402 (GOI F23 / 22) protects an arrangement for level measurement in pressure vessels. In this case, in the middle of the pressure vessel, an electrically heated rod provided with a longitudinal bore is arranged vertically, on the surface of which thermoelements are welded gas-tight at specific axial distances. Other thermocouples are located at different heights in the pressure vessel to measure the temperature of the media. The thermocouples on the rod are connected directly to a summer. The media temperature thermocouples are connected to the summer via an inverting summer. This is then followed by a signaling device.

In this measuring principle, the different heat transfer between a solid body and a liquid or ainem gas are exploited.

This arrangement is applicable only to closed containers that are filled only with gases or liquids. A loading of solids leads to the damage of the arrangement. A daily hygienic cleaning is possible only with disproportionately high expenditure of time.

Object of the invention

The aim of the invention is a sensor for Füllstandsl trolling on liquid containers, in particular sausage boilers, which allows effective control of the level dip 'prevents elimination of a Füllstandsminimunis and without increased labor costs, the feed and cleaning allowed.

Explanation of the essence of the invention

The object of the invention is to provide a sensor for level control of liquid containers, especially sausage boilers, which allows the mechanical loading of the container is not damaged by this, is not affected by the filling in its function and allows hygienic cleaning.

According to the invention, this object is achieved in that a flush with a recessed sensor surface is arranged in a pipe socket on an inner side of the container double wall, that two rods are arranged thermally conductive and directed into the pipe socket and that at the first of the rods an electrical Heating resistor and the second of the rods, a temperature sensor is arranged thermally coupled.

A particularly advantageous embodiment according to the invention is characterized in that a control circuit for the electrical heating resistor, including the heating of the sensor is arranged by external heat sources to avoid destruction of the non-liquid-covered sensor by overheating.

embodiment

The invention will be explained below with reference to preferred embodiments. It shows:

Figure 1: level sensor, longitudinal section

FIG. 2: section A-A through FIG. 1

Figure 3: Sensor with regulation of the sensor heating by heating medium of the cooking vessel and self-heating of the sensor

Figure 4: Arrangement for controlling a cooking kettle.

The sensor works according to the following principle:

A heat source and a temperature sensor are thermally coupled by a thermally conductive Sersorfläche. The temperature of the system is higher than the temperature of the surrounding area when the sensor surface is uncovered.

When covered sensor surface of this is removed by the medium heat, and the Temperuturabfall is evaluated with an electronic circuit. This principle is applicable to all liquid containers, wherein the amount of heat used for the measurement of the type of filling, for. B. cooled mayonnaise must be adapted by a few unaulwendige attempts. With appropriate material and component selection and structural design of the use of the level sensor is also at higher temperatures and different media such. As fat or oil possible. However, the problem of the flash point has to be considered.

For applications in cooking kettles, this principle of action can be realized as follows:

A heating element is in thermal contact with a thermally conductive sensor surface, which is mounted in the amount of the minimum water level thermally insulated from the boiler wall on the inner wall. As long as this sensor surface is covered with water, its temperature can not rise significantly above the dos water.

If the sensor surface is not covered with water, its temperature rises. The temperature at the other end of the sensor surface is detected and evaluated with a temperature sensor. In the case of a sensor surface afflicted with grease residue, a reliably evaluable temperature difference between the dry-heated sensor and the water-covered sensor is produced.

example 1

FIG. 1 shows a fill level sensor according to the invention in longitudinal section.

FIG. 2 shows the cross section AA. In the double wall 1 of a Brühkessels is a pipe socket 2, the inner diameter of which is reduced to the boiler interior. Side facing. Inside the pipe socket 2 is a circular, specially shaped disc 3, which consists of a correspondingly resistant material, for. As polytetrafluoroethylene (PTFE) consists.

Inserted flush in it is a circular, flat Sensoi flat 4, c'ie z. B. made of copper with a food-resistant metallic Oberf surface coating and is connected to two thermally conductive bars 5. The first of the bars 5 is provided with an electrical heating resistor 6 and the second of the bars 5 with a temperature sensor 7,

z. B. Diokschicht-temperature sensor (PTC), thermally coupled. A screw 8, which is screwed onto the pipe socket 2, effected by means of a sleeve 9, a seal of the disc 3 and has in the middle an opening for the passage of the cable 10, which is connected to an electronic circuit arrangement, which is usually used for the evaluation of temperature sensor signals becomes.

This circuit generates in a conventional manner when exceeding a certain sensor temperature, a signal indicating the undershooting of the minimum level and the sensor heater off.

Example 2

Figure 3 shows an improved level sensor. As in Example 1 this has you same circular sensor surface 4, which is connected to two thermally conductive rods 5, one of which is thermally coupled to an electrical heating resistor 6 and the other with a temperature sensor 7. In addition, the rod 5 is connected to the heating surface 6 on the side facing away from the sensor surface 4, with a heat-conducting surface 11 on which a second temperature sensor 12 is located. This is: connected by the cable 10 with a commonly used electronic circuitry, which evaluates the temperature difference between the temperature sensor 7 and the second temperature sensor 12.

As temperature sensors, for example, mutually connected thermocouples can be used, which generate a temperature difference corresponding 1 hermo voltage. This difference approaches zero when the minimum filling level is fallen below, which triggers a corresponding signal. When using the differential circuit, a third temperature sensor 13 is used to measure the housing temperature. A commonly used electronic circuit generates a signal for switching off the sensor heater when a certain sensor temperature is exceeded. As a result, the heating of the sensor by external heat sources (eg steam) in the double wall exerts no disturbing influence on the function of the sensor as long as the maximum operating temperature of the sensor is not exceeded when the sensor heating is switched off.

The interior of the sensor works in a similar way to a thermostat with internal (electrical * and / or external (eg steam) heating, which is deprived of more or less heat by the sensor surface and leads to a temperature change of the same by the one with high thermal conductivity With the appropriate choice of material and component as well as structural design, the use of the level sensor is also possible at higher temperatures and different media, eg fat or oil, but the problem of the flash point has to be considered.

Example 3

FIG. 4 shows an arrangement which implements the automatic wafer filling and heating activation and deactivation of a container 14. The level sensors according to the invention, lower 15 and upper 16, are in the amount of the minimum or maximum level in the container wall and are connected to the inputs of a commonly used electronic circuitry 17. This supplies on the output side an I.Signal 18 for controlling the filling 19, a 2.Signal 20 for controlling the heater 21 and an alarm signal 22 for signaling of disturbances, such. Failure of the water supply.

Claims (2)

1. Sensor for level control of liquid containers, in particular sausage boilers, based on different heat transfer from a substance to a second material in different physical states mounted in a container double wall, characterized in that in a pipe socket (2) on an inner side of the container double wall (1) flush fitting a disc (3) with a recessed sensor surface (4) is arranged, that on the sensor surface (4) two rods (5) are heat-conductive and directed in the pipe socket (2) and in that the first of the rods (5) has an electrical heating resistor (6) and to the second of the rods (5) a temperature sensor (7) is arranged thermally coupled. 2. Sensor according to claim!, Characterized in that the electrical heating resistor (6) is connected to a control circuit.