DE3925016A1 - Liq. glaze application control - e.g. during glazing of ceramic tiles - Google Patents

Abstract

In the control and regulation of liq. glaze application during glazing of ceramic tiles or the like in a plant comprising an article feed line (1), a glaze application unit (3), a container (4) with a constant glaze level for supplying the application unit and a system (6) for feeding glaze to the container (4), the novelty is that, during plant operation, the following steps are carried out: (a) glaze feed to the container (4) is temporarily interrupted; (b) the speed of glaze level drop in the container is measured; and (c) the measured speed is compared with a predetermined reference value of the weight of glaze deposited on each article. Equipment for carrying out th process is also claimed. Equipment for controlling liq. glaze flow rate, in plants for glazing ceramic tiles or the like, comprises (i) an electric motor-driven shaft (22) carrying one or more radial elements (24) for immersion in the glaze; and (ii) a system for measuring the electrical energy requirement for rotating the element(s) (24) in the glaze. ADVANTAGE - The amount of glaze applied to each article can be automatically controlled using simple, inexpensive and reliable equipment.

Description

The present invention relates to systems for Glazing ceramic tiles or similar objects the one with liquid glaze, comprising a feed path of objects, a unit that is used to apply the Glaze on the counter on this track stands is suitable, a container that has a con constant glaze mirror, which contains the levy unit supplies, and appropriate means to the container add the glaze. The order funds exist typically from glaze sprayer in the form of a Disc packs, or from cup droppers, or from Be layer with a matrix or with a bell, or from spray guns. This is essentially to order materials that are suitable, a con constant amount of glaze.  

To an acceptable quality standard of the finished Having tiles, it is extremely important that the Apply the glaze to the tiles with absolutely constant properties, especially with regard to Lich the amount of weight added to each tile is brought, and also in terms of density and Flowability of the glaze.

On the other hand, these properties can be derived from the various reasons, unwanted and practical uncontrollable, easy to change.

For example, the feed rate change the objects on the track.

It can also contain part of the water in the glaze Main container in front of the mentioned container with constant evaporate at the level and thus the density and the Change the flow rate of the glaze.

In addition, the line can, at least partially clog the container at a constant level connects, whereby the amount of glaze applied ver will change.

Furthermore, the ambient temperature and the temperature sway in the main container of the glaze.

For all of these reasons, it is extremely important constantly checking the glaze application and therefore also follow regulations in such a way that possible errors regarding these properties kor rigged (unit weight on the tiles, you te and flow rate) to achieve that  these precisely and in a constant manner the given Values.

These functions are still used today, in almost all cases len, carried out only by hand, i.e. it will be out of time currently taking some samples of items which the necessary weight measurements of the glaze be made and also by hand the density and flow rate of from the Glaze samples taken from the appropriate containers will measure, and you will ultimately also be influenced by Hand the supply of the order unit or the loading the glaze to correct any errors rig.

When trying to control and regulate mechanizing and automating were effective same systems proposed, which control the Tiles along the glaze run before and after the up carry out the unit.

These systems have proven to be complicated and costly lig, and their application is currently extreme limited.

The present invention is based on the object to remedy the above-mentioned evils and the same early a procedure and a corresponding device realizing to mechanical and automa table way the application of the glaze and especially the Weight amount of the glaze distributed on the tiles control and regulate, while also constructively simple and relatively cheap and should be very reliable.  

According to the invention, this object is achieved by the drawing part of claim 1 mentioned features ge solves.

Thanks to the present invention, it is also possible Lich, automatically the density and flow control glaze speed and auto to correct the changes.

The invention is detailed below with the help the accompanying drawing, which some Represent embodiments of the device.

It shows:

Fig. 1 is a schematic representation of the device of this invention;

Fig. 2 is a diagram showing the weight values of the Gla sur on each tile in dependence on the measured time;

Fig. 3 shows a second embodiment of the container age ( 4 ).

A typical installation in which the present invention is applied comprises a feed path ( 1 ) of the objects ( 2 ) (in particular ceramic tiles). A unit for dispensing the glaze onto the objects ( 2 ) is arranged on the web ( 1 ).

In the figures, this dispensing unit comprises a Schei benzerstäuber ( 31 ) which, by rotating at high speed, hurls the glaze at a full angle; a part of the thus outputted glaze distributed on the tiles (2) which is returned through under the discs (31) and the remaining amount is collected and surrounds of a cell (32) ben the ticket (31).

The dispensing unit ( 3 ) can also be in another form, for example in the form of a cup dripper or a film application by means of a die or bell or in the form of a spray gun.

In front of the unit ( 3 ) a container ( 4 ) is provided, which ensures the unit ( 3 ) by means of a line ( 5 ). This container ( 4 ) contains a constant glaze level (B), and in the known systems it only has the task of maintaining its own level and thus the pressure of the glaze which supplies the unit ( 3 ).

This container ( 4 ) is constantly provided with means ( 6 ) and provides an outlet opening ( 7 ) which is attached at its own end.

The means ( 6 ) convey a quantity of glaze into the container ( 4 ) which is not less than that which is passed from there to the unit ( 3 ); The excess glaze is emptied by means of this opening ( 7 ) and in the container ( 4 ) thus a constant level (B) is maintained, just determined by this opening ( 7 ).

In particular, the means ( 6 ) comprise a pump ( 34 ) which is immersed in a large container ( 35 ) which contains liquid glaze and which supplies the container ( 4 ) by means of a line ( 36 ).

A valve ( 8 ) is arranged along the line ( 5 ) after the container ( 4 ) in order to regulate the flow rate of the glaze which flows into the unit ( 3 ).

During normal operation of the system, the means ( 6 ) continuously convey glaze into the container ( 4 ), which supplies the dispensing unit ( 3 ) by means of the valve ( 8 ). The opening of the valve ( 8 ) is regulated in a predetermined manner, in accordance with the desired throughput of the glaze that reaches the unit ( 3 ) and from this it is more or less partially released onto the tiles.

According to the present invention, while the plant is in operation, the following phases are planned.

One first causes the glaze supply to be temporarily interrupted by the means ( 6 ) on the container ( 4 ). In practice, this is done by switching off the pump ( 34 ) and closing the shut-off valve ( 37 ) installed in the line.

This lowers the level of the glaze in the container ( 4 ), which further supplies the delivery unit ( 3 ), which in turn continues to operate.

One therefore measures the speed at which the level of the glaze in the container drops, and thus achieves a value which speaks directly proportional to the amount of glaze that is conveyed to the unit ( 3 ) and released by the water. While maintaining the operating conditions of the system (in particular the speed ( 1 ) and the dimensions of the objects ( 2 )), this value depends on the weight of the glaze applied to the tiles.

The speed value achieved in this way is also included predetermined reference benchmarks of those on the tiles compared amount of glaze applied.

In order to measure this speed, the time that the free mirror of the glaze in the container ( 4 ) needs to measure a constant, predetermined path (L) between the two fixed along the height of the container ( 4 ) at ( A 1 ) and at levels (A 2 ).

This measure is actually dependent on the speed, and if the container ( 4 ) should have a constant cut ( Fig. 1), it is inversely proportional to the speed.

After this measurement has been carried out, the means ( 6 ) are reactivated and the container ( 4 ) is again supplied by the container ( 35 ), as in normal operation.

Of course, this measurement is carried out periodically to keep the system under constant control. The device for performing the described method essentially comprises a cylindrical and elongated vessel, generally arranged with a vertical axis, which forms said container ( 4 ).

On the container ( 4 ) two sensors ( 9 ') and ( 9 '') are arranged, which are suitable for measuring the presence of the free mirror of the glaze, and which are mounted at a constant, axial distance from each other.

The sensor ( 9 ') is at the fixed level (A 1 ), slightly below the level (B) in the container ( 4 ) and the sensor ( 9 '') is at a distance (L) from (A 1 ) located at the lower fixed level (A 2 ).

In particular, these sensors ( 9 ') and ( 9 '') capacitive electronic proximity sensors, which are activated when the free mirror of the glaze coincides accordingly with the level (A 1 ) and (A 2 ).

Furthermore, suitable means for time measurement are seen before (usual and not shown), which are assigned to the signals from the sensors ( 9 ') and ( 9 ''), so that the time can automatically be measured, which is the free mirror of the glaze needed to activate these sensors ( 9 ′) and ( 9 ′ ′), that is, to switch from level (A 1 ) to level (A 2 ).

The reference data for the speed or theoretical values can be taken theoretically; they can also be taken out depending on of changing factors of the system, e.g. the before thrust speed of objects leading to glaze surface of an object, the density of the Glaze, etc.

This reference data can also, what is likely to happen is to move, tentatively from the system itself or be taken from a similar system.

The device can also turn off automatically  include values (common and not shown in the figures provided), in the form of a computer that is suitable automatically compare the time measurements to who te and save the time measurements with the reference data to compare.

Furthermore, a servomotor ( 11 ) can be provided to actuate the valve ( 8 ), which is connected to the evaluator in such a way that, if it detects an error between the time measurement and the reference data, the actuation of the servomotor ( 11 ) caused so that it becomes active and the valve ( 8 ) rotates in a calculated time so that the error is corrected.

The inside diameter of the container is 64 mm, for example, the distance (L) is 27 cm and the diameter of the maximum opening of the valve ( 8 ) is 20 mm.

The application device ( 3 ) uses a atomizer with disks of 150 mm in diameter and approximately 2000 revolutions per minute.

If one assumes that the feed speed of the web ( 1 ) is 15 m per minute, the density of the glaze is 1500 g per liter and the tiles are square with a side length of 330 mm, the test shown in Fig. 2 is obtained experimentally Image where the weight values (P) on each tile are entered in grams on the ordinate and the time values that the free mirror of the glaze needs to change from (A 1 ) to (A 2 ) in the abscissa.

For example, if you want the weight (P) to be 20 g, the reference time is 8 seconds and every time a different time is measured, the evaluator actuates the servo motor ( 11 ) in such a way that the opening of the valve ( 8 ) becomes larger or smaller, so that the quantity delivered to the order unit ( 3 ) is changed and the error is thus corrected.

In Fig. 3 another embodiment of the loading container ( 4 ) is shown.

This shape provides a central body ( 41 ), with increased capacity and diameter, on the top and bottom corresponding pipe sections ( 42 ) and ( 43 ) are added, which have a relatively small diameter.

The level (A 1 ) is provided in the pipe section ( 42 ) above the body ( 41 ) and the level (A 2 ) is provided in the pipe section ( 43 ) below the body ( 41 ).

This shape allows a more precise detection of the existence of the free mirror by the sensors ( 9 ') and ( 9 ''), but without the container ( 4 ) being too high, since in the levels (A 1 ) and ( A 2 ) the diameter is small and at the same time the measured time values are not excessively short (this is beneficial for the accuracy of the control in general).

Said device can also provide means for the Include control of glaze density.

These means comprise a container ( 15 ) which is suitable for receiving a sample amount ( 14 ) of glaze which is supplied through a line ( 16 ) connected to the opening ( 7 ).

Furthermore, measuring means of the weight of the container ( 15 ) are provided with a corresponding content of glaze, in particular an electronic loading cell ( 18 ), supported by a solid structure ( 19 ) on which the container ter ( 15 ) rests freely.

The measurement of the weight of the container ( 15 ) is carried out during said measurement of the Sinkge speed of the level in the container ( 4 ) after this level has fallen below the opening ( 7 ). In this situation, the glaze in the container ( 15 ) remains calm since there is neither a supply by means of the line ( 16 ) nor an emptying by means of the line ( 17 ) and thus the weight is measured with accuracy.

This weight measurement is directly proportional to the density, since the capacity of the container ( 15 ) is constant. The said evaluator can possibly compare the measurement of the density with the reference data and then possibly act accordingly to correct the error by ordering the addition of water or glaze of higher density in the container ( 35 ), assuming that the measured density should be higher or correspondingly lower than the reference.

The present invention may also include a device ( 21 ) for controlling the flowability of the glaze. This device ( 21 ) comprises a shaft ( 22 ) which is driven by an electric motor ( 23 ), to which one or more radial elements ( 24 ) are attached, each consisting of a crossbar.

The device ( 21 ) is in a container ( 25 ) containing a glaze pattern to be tested ( 26 ), so that the elements ( 24 ) are immersed in the glaze. It also includes suitable means, known and not shown in the figures, for measuring the electrical energy consumption necessary to cause the elements immersed in the glaze to rotate at a predetermined speed.

Since the power taken up for the rotation of the elements ( 24 ) is in relation to the flowability of the glaze, a functional value of the flowability is obtained if one measures this.

Said evaluator may be able to compare the measurement of the flowability with reference data and possibly act accordingly by supplying thinner substances or glaze with greater flowability into the container ( 35 ) if the measured flowability is higher or correspondingly lower than the reference should be.

Appropriately, the container ( 25 ) is arranged after the loading container ( 15 ) and receives the glaze that comes from the line ( 17 ).

Of course, the present invention numerous changes in natural application practice experienced without the scope of the concept of invention  leave, according to the following claims.

Claims (9)

1. A method for checking and regulating the application of liquid glaze in glazing systems of ceramic tiles or similar objects, comprising a system comprising:

• - a feed path ( 1 ) of the objects;
• - An application unit ( 3 ) of the glaze on the objects transported on this track ( 1 );
• - A container ( 4 ) containing a constant glaze level, which supplies the application unit ( 3 );
• - Means ( 6 ), suitable to promote the glaze in this loading container ( 4 ),

characterized in that it comprises the following phases while the plant is in operation:

• - Temporary interruption of the glaze supply into the container ( 4 );
• - Subsequent measurement of the speed at which the glaze level in the container ( 4 ) falls;
• - Comparison of the measured speed value with the specified reference guide values for the amount of weight of the glaze applied to each object.

2. The method according to claim 1, characterized in that in order to measure this rate of descent of the glaze level, the time is measured that the free mirror of the glaze in the container ( 4 ) requires a predetermined distance (L) between the two fixed levels Place (A 1 ) and (A 2 ) back along the height of the container ( 4 ). 3. The method according to claim 1, characterized in that this reference data tentatively depending on the properties of the glaze and / or to cover the the surface of the individual objects and / or the Feed speed can be taken from the web. 4. An apparatus for realizing the method of claim 2, characterized in that it comprises:

• - A vessel with a vertical axis, which forms the loading container ( 4 );
• - Sensor means ( 9 ') and ( 9 '') to indicate the presence of the free mirror, attached to this loading container ( 4 ) at two levels (A 1 ) and accordingly (A 2 ), in the fixed position one above the other arranged, these levels (A 1 ) and accordingly (A 2 ) below the normal glaze level (B) in the container ( 4 );
• - A time measuring device coordinates with the signals of the said sensor means ( 9 ') and ( 9 '') to measure the time that the free mirror of the glaze needs to be to bring said sensor means into action.

5. The device according to claim 4, characterized in that the container ( 4 ) comprises a central body ( 41 ) which has a relatively higher capacity and larger diameter, on which, above and below, the corresponding pipe sections ( 42 ) and ( 43 ) are attached, which have a correspondingly smaller diameter ha, the level (A 1 ) in the pipe section ( 42 ) above the body ( 41 ) and level (A 2 ) in the pipe section ( 43 ) below the body ( 41 ) being provided . 6. The device according to claim 4, characterized in that it comprises:

• - an automatic evaluator to compare these time measurements with the reference data and to act on the errors found;
• - A flow control valve ( 8 ), arranged after said container ( 4 ) and actuated by a servo motor ( 11 ), the evaluator actuating the servo motor ( 11 ) when it detects an error between the time measurements and the reference data in order to determine the error correct.

7. The device according to claim 4, characterized in that, in order to control the density of the glaze, summarizes:

• - A container ( 15 ) to contain a sample amount of glaze, supplied by means of a line ( 16 ) connected to the outlet opening ( 7 ) of the container ( 4 ) at a point above the levels of the sensor medium ( 9 ') and ( 9 '') attached and provided with an outlet ( 17 ) at maximum level;
• - Means for measuring the weight of the glaze-filled container ( 15 );
• - The measurement of the weight, made after the level of the glaze in said container ( 4 ) has fallen below said outlet opening ( 7 ).

8. Device for controlling the flow rate of the liquid glaze in glazing systems of ceramic tiles or similar objects, characterized in that it comprises:

• - a shaft ( 22 ) driven by an electric motor to which one or more radial elements ( 24 ) are connected, suitable for being immersed in the glaze for control purposes;
• - Suitable means for measuring the electrical energy requirement, which is necessary to bring these ge called elements ( 24 ) in the glaze in rotation.