EP0574757A1 - Procedure and apparatus for drying or baking - Google Patents

Abstract

The invention relates to a method and a device for setting up driers or ovens for thermally treating dry goods, particularly green ceramic bricks. To set up the operating parameters, the behaviour of the dry goods (9) during the operation in the drier (1) is registered in real time by an accompanying internal measurement value acquisition system (10) with suitable measurement value pickups (16, 17, 18). The measurement values are preferably continuously registered. The data are then signalled at intervals by means of wireless remote data transmission to an external evaluating and control device (19). The thermally insulated measurement value acquisition system (10) is transported on one or more drying racks (7) and has at least one transmitter (11) and possibly also a receiver (12).

Description

The invention relates to a method and a device for setting up dryers or ovens for the thermal treatment of dry goods with the features in the preamble of the main method and device claim.

Newly commissioned dryers, kilns or similar thermal treatment plants must be set up for the dry material to be treated. A facility is also required when switching to a new type of dry material. In practice, the operating parameters are determined empirically. Here, default values obtained from experience are set and tested in a test run with dry goods. After the run, the dry material is examined and, based on the results obtained, the parameter image for a new test run is changed. In this way, you gradually feel your way through to a final setting of the operating parameters. The procedure costs a lot of time on the one hand and on the other hand does not always lead to optimal results. In addition, a stock of dry goods must be sacrificed as rejects for each dry run, which causes considerable set-up costs.

It is an object of the present invention to provide a method and an apparatus which allow a dryer, an oven or the like to be operated in a shorter time at a lower cost and with the possibility of better Set up optimization.

The invention solves this issue with the features in the main method and device claim.

The invention provides for monitoring the behavior of the dry material within the dryer and during the process and for reporting the data obtained to an external evaluation and control device. As a result, the operating parameters of the dryer can be set up optimally, quickly and inexpensively.

It is advisable to record the measurement data relevant to the behavior of the dry material in real time and report it to the external evaluation and control device. As a result, the dry material reactions to the set operating parameters can be checked immediately. When setting up, you can approach the parameter optimum faster and with fewer steps.

Thanks to permanent real-time monitoring, you can also determine the development of stress cracks or other developments damaging or damaging the dry goods in good time, and the safety distances in the parameter setting can be selected accordingly lower. Ultimately, the amount of waste when setting up the dryer is significantly reduced.

According to the invention, a measured value recording system is used to determine the behavior of the dry goods, which is carried along with the dry goods. The data acquisition system is self-sufficient and cannot establish a fixed connection to the outside via a cable tractor or the like. A cable presents significant thermal problems at the usual temperatures with itself, which can also manifest itself in the falsification of measured values. This difficulty is eliminated in the measured value recording system according to the invention and in the wireless remote data transmission by radio, infrared or the like.

The data acquisition system is thermally insulated. For thermal reasons, it is also advisable to carry out data transmission at intervals. As a result, the internal heating of the measured value recording system by the transmitter is reduced with its mostly unfavorable efficiency. In addition, the interval transmission helps to save the electricity from the battery and thereby extend the operating time or, if necessary, save weight by reducing the capacity.

The interval transmission can be triggered and controlled in different ways. However, the measurement data acquisition preferably runs continuously. At least some of the measured data can also be evaluated in the measured value recording system. In this case, data is transmitted externally or only after a certain preset threshold value has been exceeded or fallen below. The threshold value monitoring reduces the risk of damage or destruction of the dry goods and enables a timely alarm. In this way, personnel do not have to be present at all times when setting up the dryer.

The method according to the invention and the associated device are suitable for any types of dryers, ovens or the like other thermal treatment devices. For the purposes of the invention, they are all referred to as dryers summarized. The dry material to be treated can vary in the same way. The invention is particularly suitable for chamber or tunnel dryers for the thermal treatment of ceramic moldings. The moldings can be dried by direct heating and / or heated and conditioned dry air.

The invention offers particular advantages for a tunnel dryer. A tunnel dryer usually has several mutually isolated drying zones in which different operating parameters prevail. The drying zones are gradually passed through for the dry goods. If several measurement data acquisition systems are used, the operating parameters can be changed at short notice in zones and the results can be read immediately from the subsequent zone loading.

Further advantageous refinements of the invention are specified in the subclaims.

Fig. 1:

in Draufsicht den schematischen Aufbau eines in mehrere Zonen unterteilten Trockners mit mehreren Meßwerterfassungsystemen und einer gemeinsamen externen Auswerte- und Steuervorrichtung und

Fig. 2:

in einer schematisierten und vergrößerten Seitenansicht ein Trockengestell mit einem Meßwerterfassungssystem und die Auswerte- und Steuervorrichtung.

The invention is shown schematically and by way of example in the drawings. Show in detail

Fig. 1:

in plan view the schematic structure of a dryer divided into several zones with several measured value recording systems and a common external evaluation and control device and

Fig. 2:

in a schematic and enlarged side view of a drying rack with a measured value recording system and the evaluation and control device.

In Fig. 1, a dryer (1) is shown in the form of a tunnel dryer for ceramic moldings. The dryer (1) is subdivided into several mutually partitioned zones (2), in which the dry material (9) is exposed to dry air which is conditioned in different ways according to temperature and humidity. One or more fans (3) and a heater (4) are arranged in each zone (2).

As illustrated in FIG. 2, the dry material (9) is stored on mobile drying racks (7), which get into the dryer (1) on rails (8) via end locks (5) and can move out again after passing through the zones (2) . A signal transmitter (6) can be arranged on the entrance-side lock (5), which signals the entry of a new drying rack (7). Similar signal transmitters (6) can also be arranged at other relevant locations inside the dryer (1), for example on the zone bulkheads.

The dryer (1) shown with its division and internal design can vary as desired. The same applies to the drying racks (7). A chamber dryer in which the dry material is treated in a stationary manner may be mentioned as alternatives. In the tunnel dryer, however, the dry material (9) is treated in one pass. The dryer (1) could also be a kiln, a kiln or the like other heat treatment device. The dry material (9) can also vary as desired. This can also influence the design of the drying racks (7). For example, the ceramic moldings (9) could also be pushed as a continuous strand through a dryer and / or a burner and only then divided into individual moldings. Instead of mobile drying racks (7), slideways or similar other means of funding are also possible.

When starting up or changing the type of dry material (9), the dryer (1) must be set up with its operating parameters. Different operating parameters are required for the different zones (2). For example, this would be the strength, duration, direction, reversing cycle, temperature and humidity of the air flow in the individual zones (2). To do this, the blowers (3), the heaters (4) and the fresh or wet air supply must be set and controlled accordingly. Further operating parameters would be, for example, the throughput speed or the length of time that the dry goods (9) or the drying racks (7) stayed in the zones (2). The operating parameters depend on the desired drying process in the dry material (9). The dry material (9) should dry as evenly as possible. On the one hand, this affects the progress of drying on the outer skin of the respective molding and, on the other hand, the achievement uniform degree of drying in the lining of the drying rack (7). If possible, there should be no drying differences between the outer and inner moldings of the trim.

In order to simplify the setup of the dryer (1) and the definition of the optimal operating parameters, the behavior of the dry material (9) and its reaction to changes in the operating parameters are monitored. For this purpose, a measured value acquisition system (10) is arranged on individual or on all drying racks (7), which reports the measured data determined in the process via wireless data transmission to an evaluation and control device located outside the dryer (1). Here the measurement data can be displayed, saved and logged. Based on the status messages, the operating parameters in the dryer (1) or the individual zones (2) are changed until the desired drying process is achieved.

As illustrated in FIG. 2, the measured value recording system (10) is housed in a thermally insulated housing (15) and is preferably arranged in the relatively cool bottom area of the drying rack (7). Measuring sensors (16, 18) are arranged on one or preferably several ceramic moldings (9), which provide relevant physical data on the condition of the dry material. The measuring sensor (16) is designed, for example, as a moist probe which is embedded in a suitable manner in the ceramic molding (9). The transducer (18), on the other hand, is designed as a strain gauge cell, which measures the weight of the molding (9) as a type of pressure sensor and thus conveys information about the water content or the progress of drying. Alternatively or in addition, Vibration measurement suitable displacement sensors, such as potentiometers, are used.

Reference number (17) denotes a temperature sensor which is positioned on the drying rack (7) in the embodiment shown and measures the prevailing ambient temperature. A moist probe can also be provided in the same way. Alternatively or additionally, a temperature sensor can also be arranged on or in a ceramic molding (9). Basically, all types of transducers can be used that provide relevant physical data.

The transducers (16, 17, 18) are connected to the data acquisition system (10) via suitable lines. In this case, they are preferably connected to a computer (14) which is equipped with a microprocessor and has a program memory, a data memory for preset values and an intermediate memory about the data supplied by the measurement sensors (16, 17, 18). The data input lines are preferably connected in parallel, so that the incoming measurement data can be processed simultaneously and in parallel.

The measured value recording system (10) has a transmitter (11) for wireless data transmission, which is preferably designed as a radio, but can also be an infrared transmitter or another suitable device. In addition, the measured value recording system (10) can also have a receiver (12).

The transmitter (11) and the receiver (12) are connected to the computer (14) by data lines. A converter (not shown) is preferably connected to the data connection, which converts the data processed in parallel in the computer converted into serial data and sent to the transmitter (11) or received by the receiver (12). In this way, the number of transmit and receive channels can be kept smaller than the number of measurement data. Depending on the embodiment of the measured value recording system (10), the converter can also be omitted.

The measured value recording system (10) has its own on-board power supply (13) from which the consumers are fed. This is preferably a battery or a rechargeable battery.

The measured values can be recorded continuously using the sensors (16, 17, 18). The data transmission by the transmitter (11), however, takes place at intervals. The transmitter (11) is only switched on for a short time. The intervals can be determined internally or externally.

The measurement data is preferably acquired, processed and transmitted from the measurement value acquisition system (10) to the external evaluation and control device (19) in real time. The evaluation and control device (19) has at least one receiver (20) corresponding to the transmitter (11). It can additionally have a transmitter (21) which communicates with the receiver (12) of the measured value recording system (10). A computer (22) with a microprocessor, suitable data and program memories, display elements etc. is preferably also provided in the evaluation and control device (19).

In the embodiment of FIG. 1, several measured value acquisition systems (10) are in use simultaneously in the dryer (1) and communicate with a common external evaluation and control device (19). To selectively address the measured value acquisition systems (10), these are and the common evaluation and control device (19) is equipped with suitable coding devices. For example, coding is carried out using a radio key with a bit pattern. On the one hand, the evaluation and control device (19) can use the radio key to specifically address the individual measured value acquisition systems (10). Conversely, the evaluation and control device (19) can identify the transmitting measured value acquisition systems (10) and assign the received data using the same coding.

The measurement data can be recorded and transmitted intermittently in different ways.
In one embodiment, the measured value recording system (10) is switched on remotely from the outside by the evaluation and control device (19). It records the data from the transducers (16, 17, 18) and sends them via the transmitter (11) to the evaluation and control device (19). The intervals can be specified by an operator or a program in the evaluation and control device (19). The transmission intervals can also be linked to certain operating events in the dryer (1). For example, the entry or the position of a drying rack (19) can be reported to the evaluation and control device (19) via the signal transmitters (6). For example, such a signal transmitter (6) can be designed as a light barrier on the lock wall or a zone bulkhead. With this signal, zone changes can be signaled and, depending on this, the measured value acquisition can be permitted.

Alternatively, the intervals or the transmission clock can also be specified by the measured value acquisition system (10). On the one hand, this is possible through an integrated timer, with which fixed intervals are preferably set.

In parallel at specified intervals or instead there is also another determination option. In the case of continuous measured value acquisition, data are continuously supplied to the measured value acquisition system (10), which are evaluated and prepared before the shipment. They are stored in the buffer at least temporarily and compared with one another. The comparison can be made, for example, by means of a differentiation in order to detect special, in particular sudden changes in the state of the dry material (9). Alternatively, the incoming data can also be compared with stored default values or threshold values. As soon as a special data event occurs, for example the abrupt change in state or a significant overshoot or undershoot of the threshold value, the computer (14) transmits the data to the transmitter (11) for transmission. In this way, data transmission can also take place between the defined intervals in order to make special events noticeable in real time and, if necessary, to trigger an alarm.

REFERENCE SIGN LIST

1

dryer

2nd

Zone

3rd

fan

4th

heater

5

lock

6

Signal generator, light barrier

7

Drying rack, drying car

8th

rail

9

Dry goods, ceramic moldings

10th

Data acquisition system

11

Channel

12

receiver

13

Power supply, battery

14

computer

15

casing

16

Sensor, moisture probe

17th

Sensor, temperature sensor

18th

Transducer, strain gauge cell

19th

Evaluation and control device

20th

receiver

21

Channel

22

computer

Claims (20)

Method for setting up dryers or ovens for the thermal treatment of dry goods, in particular ceramic moldings, the operating parameters of the dryer being set on the basis of the dry goods behavior shown, characterized in that the behavior of the dry goods (9) during operation in the dryer (1) is characterized by a carried internal measured value acquisition system (10) and reported by means of wireless data transmission to an external evaluation and control device (19). Method according to Claim 1, characterized in that the behavior of the dry goods is recorded in real time and reported to the external evaluation and control device (19). Method according to Claim 1 or 2, characterized in that the measured values for the behavior of the dry material are recorded continuously. Method according to claim 3, characterized in that the measured values are temporarily stored and compared with preset values. Method according to Claim 1 or one of the following, characterized in that the messages from the measured value recording system (10) are transmitted to the evaluation and control device (19) at intervals. Method according to Claim 5, characterized in that the messages from the measured value recording system (10) are transmitted at a predetermined clock. Method according to Claim 5 or 6, characterized in that the messages from the measured value recording system (10) are transmitted remotely on request from the external evaluation and control device (19). Method according to Claim 5, characterized in that the messages from the measured value recording system (10) are transmitted as a function of exceeding or falling short of threshold values of individual or several measured data. Method according to Claim 1 or one of the following, characterized in that a plurality of measured value recording systems (10) are in use at the same time and transmit their messages with a distinctive coding to a common evaluation and control device (19). Method according to Claim 1 or one of the following, characterized in that the measurement data for the dry goods behavior are recorded in parallel by the measurement value acquisition system (10) and converted into serial data for the mailing. Device for setting up dryers or ovens for the thermal treatment of dry goods stored in drying racks, in particular ceramic moldings, characterized in that on one or more drying racks (7) located in the dryer (1) there is a thermally insulated measured value acquisition system (10) with one or more transducers (16, 17, 18) which record the behavior of the dry material (9) and which is supplied with a power supply ( 13) is equipped and communicates with an external evaluation and control device (19) via wireless data transmission Apparatus according to claim 11, characterized in that the measured value acquisition system (10) has a transmitter (11) which transmits the data at intervals. Apparatus according to claim 11 or 12, characterized in that the measured value recording system (10) and the evaluation and control device (19) each have a transmitter (11, 21) and a receiver (12, 20). Device according to claim 11 or one of the following, characterized in that the transmitter and receiver (11, 12, 20, 21) are designed as radio devices. Device according to claim 11 or one of the following, characterized in that a signal transmitter (6) for starting the measured value recording system (10) is arranged in the dryer (1). Device according to claim 11 or one of the following, characterized in that the measured value recording system (10) has a computer (14). Device according to claim 16, characterized in that the computer (14) has a memory for temporarily storing the measurement data, a program memory and a data memory for predetermined target values. Apparatus according to claim 11 or one of the subsequent claims, characterized in that a plurality of measured value recording systems (10) are provided for simultaneous use in the dryer, each measured value recording system (10) having a coding unit for selective addressing during data transmission. Apparatus according to claim 11 or one of the subsequent claims, characterized in that the measured value acquisition system (10) has a parallel-serial converter for converting parallel measurement and control data and serial transmit and receive data. Device according to claim 11 or one of the following, characterized in that the measured value recording system (10) is arranged in a thermally insulated housing (15).

Images