BE1022757B1 - Apparatus and method for measuring moisture in die casting molds - Google Patents

Abstract

The invention relates to a device (1) and a method for measuring the moisture in die casting molds (24), the mold cavity (25) via

a vent line (31) is connected to a venting device (28). The modular device (1) is connectable to the vent line (31) and comprises a sensor arrangement (S) by means of which the moisture of gases sucked out of the mold cavity (25) can be measured. The sensor arrangement (S) has a transmitter (7) emitting electromagnetic radiation and a receiver (14) which detects electromagnetic radiation. On the basis of the measured values determined during the evacuation process, it can be determined whether the quantity of a water-separating agent mixture which is injected into the mold cavity (25) before the actual casting process is to be changed.

Description

Apparatus and method for measuring moisture in

foundry molds

The invention relates to a device for measuring the moisture in die-casting molds according to the preamble of claim 1 and to a method for measuring the moisture in die casting molds according to the preamble of claim 18.

In order to be able to remove the finished casting from the casting mold during die casting after solidification, the mold cavity (cavity) of the casting mold is sprayed with a release agent. Such release agents are preferably water-miscible and are mixed with water in a ratio of up to 1: 100 before they are sprayed on. Ideally, when the water-mixed release agent is sprayed into the hot mold, all of the water evaporates leaving a thin release film which allows demolding of the casting and prevents the metal from sticking to the mold. The water, in addition to the function as a carrier for the release agent have the further function of cooling the mold. A problem with the use of a mixed with water release agent is thus that on the one hand enough water must be used so that a complete spraying of the walls of the cavity and possibly a sufficient cooling of the mold can be ensured. On the other hand, the amount of water should not be too large, otherwise there is a risk that the water is not completely evaporated and it comes in the subsequent casting process to water or WasserdampfBelschlüssen in the finished casting, which is of course undesirable and leads to loss of quality of the finished casting. For this reason, it would be desirable if a statement could be made about whether the water is more or less completely evaporated or if any residual water is in the mold.

An obvious variant for measuring the moisture in die casting molds would be to arrange within the die one or more sensors by means of which the moisture can be measured. However, since the die, depending on the metal to be cast, can be between a few hundred and over a thousand degrees, such a solution is virtually eliminated, since there are few sensors that can provide accurate readings over a long period of time under these conditions. Especially as the liquid metal could also damage the sensor and / or pollute it.

The object of the invention is to provide a device for measuring the moisture in die-casting molds by means of which a reliable statement can be made about the amount of water remaining in the mold after spraying the water-separating agent mixture.

This object is achieved with a device according to claim 1.

By virtue of the device being connectable to the vent line and comprising a sensor arrangement by means of which the moisture in the gases sucked out of the mold cavity can be measured, the measurement can be carried out remotely from the rough and hot surroundings of the die casting machine or the die casting mold. Such a device can be quickly and easily installed in a new as well as in an existing vent line.

Preferred developments of the device are described in the dependent claims 2 to 17.

Thus, it is provided in a preferred development that the sensor arrangement comprises at least one emitter emitting electromagnetic radiation and at least one electromagnetic radiation detecting receiver and the device is provided with a channel for passing the extracted gases, wherein the channel extends between the transmitter and the receiver , This training allows a particularly simple construction of the device.

In a further preferred embodiment, the transmitter emits electromagnetic radiation having a wavelength between 600 nm and 1400 nm, preferably between 900 nm and 990 nm, particularly preferably between 930 nm and 950 nm. By adapting the wavelength range to the specific requirements, namely the detection the proportion of water in the gas flowing through unwanted interference can be largely eliminated.

Preferably, the wavelength range detected by the receiver is limited by preceding a bandpass filter. This is a cost effective measure for selecting a wavelength range.

In a particularly preferred development, the transmitter has at least three LEDs emitting electromagnetic radiation and the receiver has a corresponding number of LEDs detecting electromagnetic radiation. As a result, a larger area can be detected and the failure of a transmitter LED and / or a receiver LED optionally compensated.

A preferred embodiment of the device provides that the LEDs of the transmitter emit electromagnetic radiation having a wavelength of 940 nm +/- 5 nm and the LED's of the receiver are provided with an integrated bandpass filter, which electromagnetic

Radiation in the range between 935 nm and 945 nm. This wavelength range has proven to be particularly useful for detecting the moisture present in the flowing gas.

Preferably, the LED's of the transmitter is followed by a perforated disc and / or the LED's of the receiver preceded by a perforated disc. A perforated disc is a particularly simple and inexpensive measure to prevent interference between the radiation emitted by the individual LED's -Signale-.

If several LEDs are provided, these are preferably distributed over the cross section of the channel. As a result, the moisture present in the gas flowing through is not only detected selectively or in strips.

In a further preferred development of the device, the transmitter and / or the receiver is arranged behind a glass pane which allows the radiation emitted by the respective transmitter to pass largely. Such a glass pane provides effective protection against unwanted external influences and damage, but without adversely affecting the measurement result.

In an alternative development, the glass pane is provided with a bandpass filter, which allows electromagnetic radiation to pass within a certain wavelength range. Again, this is one way to selectively limit the emitted or detected wavelength range.

Preferably, a cleaning nozzle provided with at least one outlet opening is arranged in front of the respective glass pane in such a way that a cleaning medium under overpressure can escape via the outlet opening (s) in the direction of the respective glass pane. This allows us to easily clean the glass pane.

By being constructed as a modular unit, the apparatus can be easily installed in new or existing vent lines.

Particularly preferably, the device comprises a housing which is provided with an input flange, an output flange and a leading from the input flange through the housing to the output flange channel, wherein on one side of the channel of the transmitter and diametrically opposite the receiver is arranged. Such a device can be particularly easily installed in a vent line.

In a further preferred development, the device has at least one insert detachably inserted into the housing, on which the transmitter and / or receiver and / or the glass pane (s) is / are arranged. This design allows for easy cleaning of the glass or a simple replacement of the glass or the transmitter and / or receiver.

Preferably, the device is provided with an interface, via which the sensor arrangement is electrically supplied and / or the measured data can be transmitted. This allows rapid integration into the die casting machine or the connection to the control device.

A further object of the invention is to propose a method for measuring the moisture in die casting molds by means of a device designed according to one of the preceding claims.

This object is achieved by a method according to claim 18.

By forcibly evacuating the mold cavity of the die via a vent line and measuring the water content of the gas flowing through the vent line during evacuation, the humidity in the respective die can be determined during a normal pour cycle without prolonging the pouring cycle ,

Preferred developments of the method are defined in the dependent claims 19 to 21.

Thus, in a preferred embodiment of the method during the evacuation process, a measurement cycle is performed with a plurality of individual measurements and an average value is formed from the measurements. This has the advantage that the influence of irregularities, such as individual solid particles, which are entrained by the extracted gases, do not permanently distort or influence the measurement result,

Preferably, a zero adjustment of the sensor arrangement is performed before each measurement cycle. As a result, sources of error, such as measurement inaccuracies caused by temperature changes or soiled glass panes, can largely be eliminated.

Finally, claim 22 claims a method for determining or changing the amount of a sprayed into the mold cavity of a die-casting water-release agent mixture by means of a device according to any one of claims 1 to 17.

In this case, the mold cavity of the die casting mold is forcibly evacuated via a vent line and measured or determined during evacuation of the water content of the gas flowing through the vent line by means of the device, wherein based on the measured or determined values, the absolute amount of the applied water-release agent mixture for subsequent

Spraying is determined and / or a correction factor for

Change in the amount of the injected water-release agent mixture is determined.

Hereinafter, an embodiment of the valve device will be explained in more detail with reference to drawings. In these drawings shows:

1 shows a section through the device schematically shown for measuring the moisture in die casting molds.

FIG. 2 shows the schematically illustrated device together with components of a die casting machine; FIG.

Fig. 3 is a section through an alternative embodiment of a device schematically shown again for measuring the moisture in die casting molds.

With reference to FIG. 1, which schematically shows an exemplary embodiment of a device 1 for measuring the moisture in die casting molds, the mold cavity is connected to a venting device via a venting line, the construction of the device will be explained in more detail.

The device 1 is a modular component and has a housing 2, which is provided with an input flange 3 and an output flange 4. From the input flange 3, a channel 5 leads centrally through the housing 2 to the output flange 4. By means of the two flanges 3, 4, the device can be installed in a vent line or connected to this. For this purpose, the respective flange 3, 4 may be provided with a mechanical connection means such as an external thread, a bayonet closure or the like. Alternatively, it would also be possible to provide a cylindrical jacket surface on which the vent line hose can be fixed by means of a pipe clip, a strap or the like.

In the housing 2, a total of S designated sensor arrangement is added, by means of which the moisture of a gas flowing through the channel 5 -air- can be detected. The sensor arrangement S is arranged on a plug-in module 6 and comprises a transmitter 7 arranged on one side of the channel 5 and a diametrically opposite receiver 14. The transmitter 7 is preferably a so-called LED array, which consists of a large number of SMD Technique on a print 8 arranged, electromagnetic radiation emitting LED's 9 is. Also preferably used as the receiver 14 is an LED array with a print 15 and a plurality of SMD technology disposed thereon, electromagnetic radiation detecting LED's 16 used. From the respective array lead connecting leads 12, 19 to the outside of the housing 2, wherein the lines 12, 19 preferably in a plug or an interface (both not shown) open. In front of each array, a protective glass sheet 10, 17 is arranged. In front of each glass pane 10, 17, a cleaning nozzle 11, 18 is additionally arranged, by means of which the respective glass pane 10, 17 can be cleaned by blowing on a cleaning medium, for example air, as indicated by arrows. If, in connection with the receiver 14, electromagnetic radiation-detecting LEDs 16 are used, these are in particular photodiodes. Preferably, the LEDs 9, 16 are arranged distributed over the cross section of the channel 5.

The radiation emitted by the transmitter 7 in the direction of the receiver 14 must pass through the channel 5, which is also indicated by arrows. If a medium is passed through the channel 5, this can cause a weakening of the radiation arriving at the receiver 14. Since in particular the water content in a medium flowing through is to be detected by the device 1 under discussion, but at the same time the influence of possible sources of error such as foreign gases, smoke etc. should be kept as low as possible, it is preferably measured in a specific wavelength range. Based on the findings currently obtained, it is preferred to measure in an infrared wavelength range of about 900 to 990 nm, more preferably in a range of about 930 to 950 nm, most preferably in the range of 940 +/- 5 nm. To limit the wavelength range, a bandpass filter can be arranged either after the transmitter 7, in front of the receiver 14 or after the transmitter 7 and in front of the receiver 14. Of course, transmitters 7 and / or receivers 14 with integrated bandpass filters can also be used. Another variant is to provide the one and / or the other glass pane 10, 17 with a bandpass filter or to design it as a bandpass filter.

In principle, it would also be possible to carry out the measurement in a wavelength range between 600 nm and 1400 nm, wherein within this range a certain bandwidth can be selected.

With reference to FIG. 2, which shows the device 1 together with some components of a die-casting machine in a greatly simplified form, it is explained below how the moisture in die-casting molds can be determined with the device. As components of the die casting machine, a casting chamber 22, a die casting mold 24, a spray head 26, a venting valve 27, a venting device 28, a control device 29 and a venting line 31 are shown.

Since the said components 22, 24, 26, 27, 28, 29, 31 of the die casting machine are basically known, this will be discussed only briefly or in conjunction with the device designed according to the invention.

The casting chamber 22 is provided with a casting piston 23, by means of which the liquid casting material -Metall- is conveyed into the mold cavity 25 of the die-casting mold 24. The mold cavity 25 opens on the outlet side via a vent channel 30 in the vent valve 27, which in turn is connected via the vent line 31 with the venting device in the form of a vacuum tank 28. The vent valve 27 is intended to prevent liquid casting material from the mold cavity 25 can penetrate into the environment or in the vent line 31. Between the vent valve 27 and the vacuum tank 28, the device 1 for measuring the moisture in the die 24 is arranged in the vent line 31. The spray head 26 is used for spraying a release agent so that the finished casting can be removed from the mold 24 after solidification. The to be applied. Separating agent is preferably mixed in the ratio of 1: 100 with water and is injected with open die 24 in the mold cavity 25 of the hot die, so that after evaporation of the water, a thin release film on the walls of the mold cavity 25 remains. This release film allows the demolding of the casting and prevents the adhesion of the metal to the mold or the walls of the mold cavity 25. The controller 29 is electrically connected to the device 1 and the components 23, 24, 26, 27, 28, which is indicated by dashed lines.

A measuring cycle for determining the moisture in the die 24 proceeds in approximately the following manner. When the pressure die 24 is open, the water-separating agent mixture is injected into the mold cavity 25 by means of the spray head 26. In particular, among other parameters, the temperature of the die and the amount of injected water-release agent mixture determines whether all water evaporates or only part of it. After spraying the mixture, the die 24 is closed. Before the actual measuring cycle begins, a so-called zero balance of the sensor arrangement S of the device 1 is carried out so that, for example, any contamination of the glass panes does not flow into the measurement result. Thereafter, the mold cavity 25 is evacuated by 27 gases from the mold cavity 25 and the associated channels and lines 30, 31 are sucked by means of the vacuum tank 28 via the vent line 31 and the open vent valve. With the beginning of the extraction process, the actual measurement cycle is started by either continuously measuring or performing a plurality of individual measurements. It is measured how large the attenuation of the emitted signal is or how strong the signal detected by the receiver. Due to the attenuation or the height of the received signal, a conclusion can be drawn on the proportion of water particles and / or steam in the gas flowing through (air). In order to keep the influence of possible sources of error such as foreign gases, smoke, etc. as low as possible, particularly preferably in the previously mentioned infrared wavelength range between 930 and 950 nm (nanometers) is measured.

Preferably, a measurement cycle consists of a plurality of individual measurements. Based on the measured values as well as the course, it is possible to draw conclusions regarding the moisture in the casting mold. However, a measuring cycle can also consist of a large number of individual measurements, for example from 1000 individual measurements, the average being calculated from a specific number of individual measurements, for example from 10 individual measurements, and this then being taken into account as the measured variable, so that ultimately 100 measuring points would be taken into account. As a result, for example, the influence of individual or larger solid particles, which are located in the gas flowing through, can be minimized.

Depending on the measurement result, the amount of water-release agent mixture to be sprayed on can be changed for subsequent casting operations. If the proportion of water is too high, the amount of water-release agent mixture to be sprayed on is reduced, and if necessary, the extraction process could be extended. Usually, at the beginning of a casting cycle in which, for example, a few thousand parts are to be poured, carried out before each casting a measuring cycle and possibly the amount of i aufzuspritzenden water-release agent mixture changed, and that until the relevant parameters such as in particular have the temperature of the mold and the moisture of the mold cavity have settled to a predetermined level, of course, it must be ensured that after evaporation of the water i i continuous release agent film remains. Thereafter, at predetermined intervals, for example every hour or every tenth casting operation, a measuring cycle can then be carried out and, if appropriate, parameters can be changed on the basis of the measured or determined measured values. Of course, also within the mold or the mold cavity) locally applied amount of the mixture can be changed. Depending on the measurement result, it is also possible if necessary to make changes to the shape itself, for example by attaching a bore for evacuating the water at the end of a branch of the mold cavity or behind a slide.

The end of the suction process is usually also the beginning of the actual casting process by the liquid metal is conveyed by means of the casting piston in the mold cavity after evacuation of the mold cavity. However, should it be found during a measurement cycle that the water content is too high, i. above a predetermined maximum value, if necessary, an alarm can be issued and / or the casting process can be stopped.

On the basis of the course of the measured value, it is also possible, if necessary, to make a statement in which part or sections of the mold cavity water has at most accumulated. If, for example, the water content increases towards the end of the extraction process, this indicates that there is too much water in smaller or narrower or longer "branches" of the mold cavity. If necessary, this knowledge can be used to adapt the amount of water-separating agent mixture to be sprayed only selectively or in specific areas.

Preferably, before each measurement, a cleaning of the two glass panes is carried out by means of the cleaning nozzles or a cleaning medium flowing out of them. If, in the case of the zero balance, which is preferably to be carried out before each measuring cycle, it should be determined that the glass panes are heavily or excessively soiled, for example a signal can be generated by the control device which signals additional cleaning of the glass panes or an exchange thereof. Therefore, it is advantageous if the device 1 is constructed so that the glass sheets are easily accessible.

Fig. 3 shows a section through an alternative embodiment of the device for measuring the moisture in die casting molds, wherein in particular only the differences from the embodiment according to FIG. 1 is discussed, wherein like parts are provided with the same reference numerals. The device 1 is provided on the inlet side with an exchangeable filter 39 which is intended to retain in particular larger solid particles in the gas flowing through. The filter 39 is preferably arranged exchangeably on the device 1. In addition, a perforated disk 33 is arranged between the transmitter 7 and the glass pane 10. The perforated disk 33 is designed in such a way that the light emitted by the LEDs 9 of the transmitter 7 can pass through openings-holes-in the direction of the respectively assigned receiver LED 16. The size of the openings is adapted to the requirements such that scattered light, that is light which is not emitted at a certain angle, is retained by the perforated disc 33. In front of the receiver 14, a further perforated disk 34 is arranged, whose openings do not let light, which impinges on the perforated disk 34 outside a predetermined area -opening, pass in the direction of the receiver 14. Possibly. It may be sufficient to provide only one of the two perforated discs 33 or 34. In any case, interference should be avoided by the perforated disk or the perforated disks. In this example, transmitter LEDs 9 are also used which emit light in a narrow wavelength range, preferably in the range of 940 +/- 5 nanometers. In addition, receiver LEDs 16 with an integrated bandpass filter are preferably used, which also allow only light in the predetermined wavelength range to pass.

Experiments have shown that preferably between two and eight transmitter LEDs 9 and a corresponding number of receiver LEDs 16 are used. Particularly preferably, between three and six transmitter LEDs 9 and a corresponding number of receiver LEDs 16 are provided. When providing at least three transmitter and receiver LEDs, the failure of a transmitter LED and / or a receiver LED can be optionally compensated. It is understood that as the number of LEDs increases, the insensitivity to individual LED failure decreases. Also increases with the number of LEDs and the insensitivity with respect to a partial contamination of the glass or glass panes. In terms of insensitivity, reliability, space requirements and costs, the use of four or five transmitter and receiver LED's has proven particularly useful. Preferably, the LEDs are not arranged as shown in the drawing parallel to the longitudinal axis but in a row transverse to the longitudinal axis of the device 1, so that substantially the entire cross section of the channel 5 is detected.

In addition, a pressure sensor 35 is provided, by means of which the pressure prevailing in the channel 5 can be measured. Via a connecting line 36, the pressure sensor 35 can be connected to the control device 29 (FIG. 2). In addition, a temperature sensor 37 is provided, by means of which the temperature of the gas flowing through can be measured. Via a connecting line 38, the temperature sensor 37 can be connected to the control device 29 (FIG. 2). By providing a pressure sensor 35, not only the pressure prevailing in the channel 5 may be measured, but it may additionally be determined, for example, whether there is still a gas flow in the channel 5. Possibly. For this purpose, a comparison with a further pressure sensor (not shown) can be made. Usually, a further pressure sensor is arranged on the die anyway, so that, for example, its data can be used. The i mentioned sensors 35, 37 are also particularly suitable to compare different measurements with each other and possibly by means of

Control device to influence the amount of injected water separator mixture. At best, only the pressure sensor 35 or the temperature sensor 37 can be provided as needed. Of course, more than one pressure sensor and / or more than one temperature sensor may be provided.

It is understood that the previously explained embodiments of the device is not to be regarded as exhaustive, but that quite different configurations are possible within the scope of the scope defined in the claims. Thus, for example, two plug-in modules could be provided, wherein one part of the transmitter including the associated glass pane is arranged, while on the other part of the receiver including the associated glass pane is arranged. Such a configuration allows a particularly simple cleaning or a particularly simple replacement of the respective glass pane or of the transmitter or receiver. Of course, for example, two transmitters and two receivers could be provided, which could be arranged either behind the other along the channel 5 or each offset by 90 ° to each other along the circumference of the channel 5

The main advantages of the device shown can be summarized as follows: The device enables a reliable measurement / determination of the amount of residual water possibly present in the casting mold; - By the device is arranged away from the mold and thus of the hot area of the die casting machine, the thermal load is relatively low; - The device is simple and inexpensive; - The device can be easily and quickly integrated into existing or new facilities; - The device does not affect the casting cycle;

LIST OF REFERENCES: 1. Device 36. Connection cable 2. Housing 37. Temperature sensor 3. Input flange 38. Connection cable 4. Output flange 39. Filter 5. Channel 40. 6. Insert 41. 7. Transmitter 42. 8. Print 43. 9. LED's 44. 10. Glass pane 45. 11. Cleaning nozzle 46. 12. Connections 47. 13. 48. 14. Receiver 49. 15. Print 50. 16. LED's 51. 17. Glass pane 52. 18. Cleaning nozzle 53. 19 Connections 54. 20. 55. 21. 56. 22. Casting chamber 57. 23. Casting piston 58. 24. Diecasting mold 59. 25. Mold cavity 60. 26. Spray head 61. 27. Venting valve 62. 28. Vacuum tank 63. 29. Control device 64. 30. Venting channel 65. 31. Venting line 66. 32. 67. 33. Perforated plate 68. 34. Perforated plate 69. 35. Pressure sensor 70.

Claims (19)

claims 1. Device (1) for measuring the moisture in die casting molds (24), the mold cavity (25) via a vent line (31) with a venting device (28) is connected, characterized in that the device (1) with the vent line (31 ) is connectable and comprises a sensor arrangement (S), by means of which the moisture in the extracted from the mold cavity (25) gases is measurable. 2. Device (1) according to claim 1, characterized in that the sensor arrangement (S) comprises at least one emitter emitting electromagnetic radiation (7) and at least one electromagnetic radiation detecting receiver (14) and the device (1) with a channel (5 ) is provided for passing the extracted gases, wherein the channel (5) between the transmitter (7) and the receiver (14) passes therethrough. 3. Device (1) according to claim 1 or 2, characterized in that the transmitter (7) emits electromagnetic radiation having a wavelength between 600 nm and 1400 nm, preferably between 900 nm and 990 nm, more preferably between 930 nm and 950 nm , 4. Device (1) according to claim 3, characterized in that the receiver (14) is preceded by a bandpass filter, which allows electromagnetic radiation to pass within a certain wavelength range, preferably within a wavelength range between 900 nm and 990 nm, more preferably between 930 nm and 950 nm. 5. Device (1) according to one of the preceding claims, characterized in that the transmitter (7) at least three electromagnetic radiation emitting LED's (9) and the receiver (14) has a corresponding number of electromagnetic radiation detecting LED's (16). 6. Device (1) according to claim 5, characterized in that the LED's (9) emit the transmitter (7) electromagnetic radiation in the range between 935 nm and 945 nm and the LED's (16) of the receiver (14) with an integrated bandpass filter which transmits electromagnetic radiation in the range between 935 nm and 945 nm. 7. Device (1) according to claim 5 or 6, characterized in that to prevent interferences the LED's (9) of the transmitter (7) a perforated disc (33) is connected downstream and / or the LED's (16) of the receiver (14). a perforated disc (34) is connected upstream. 8. Device (1) according to one of claims 5 to 7, characterized in that the LEDs (9, 16) are arranged distributed over the cross section of the channel (5). 9. Device (1) according to any one of claims 2 to 8, characterized in that the / the transmitter (7) behind a glass pane (10) is arranged / which allows the radiation emitted by the respective transmitter (7) largely pass. 10. Device (1) according to one of claims 2 to 9, characterized in that the / the receiver (14) behind a glass pane (17) is arranged / which allows electromagnetic radiation to pass largely at least in a certain wavelength range. 11. Device (1) according to claim 9 or 10, characterized in that the glass pane (10, 17) is provided with a bandpass filter, which allows electromagnetic radiation to pass within a certain wavelength range, preferably within a wavelength range between 900 nm and 990 nm, more preferably between 930 nm and 950 nm. 12. Device (1) according to one of claims 9 to 11, characterized in that in front of the respective glass pane (10, 17) provided with at least one outlet opening cleaning nozzle (11, 18) is arranged such that via the outlet opening (s) a standing under pressure cleaning medium in the direction of the respective glass sheet (10, 17) can escape. 13. Device (1) according to one of the preceding claims, characterized in that the device (1) is designed as a modular unit. A device (1) according to claim 13, characterized in that the device (1) comprises a housing (2) provided with an input flange (3), an output flange (4) and one of the input flange (3) through the housing (2) to the output flange (4) leading channel (5) is provided, arranged on one side of the channel (5) of the transmitter (7) and i diametrically opposite the receiver (14) is. 15. Device (1) according to claim 14, characterized in that the respective flange (3, 4) for connection to a vent line (31) is formed. i 16. Device (1) according to claim 14 or 15, characterized in that the device (1) has at least one insert inserted into the housing (6), wherein on the insert (6) of the transmitter (7) and / or receiver (7) and / or the glass sheet (s) (10, 17) i is arranged / are. 17. Device (1) according to one of the preceding claims, characterized in that the device (1) is provided with an interface via which the sensor arrangement (S) is electrically supplied and / or> the measured data are transferable. 18. A method for measuring moisture in die casting molds (24) by means of a device (1) designed according to one of the preceding claims, characterized in that the mold cavity (25)) of the die casting mold (24) is forcibly evacuated via a vent line (31) and in that during evacuation the water content of the gas flowing through the venting line (31) is measured by means of the device (1). 19. A method according to claim 18, characterized in that carried out during the evacuation a measuring cycle with a plurality of individual measurements and an average value is formed from the measurements. 20. A method according to claim 18 or 19, characterized in that before each measurement cycle, a zero balance of the sensor arrangement (S) is performed. 21. Method according to one of claims 18 to 20, wherein a glass pane (10, 17) is arranged in front of the transmitter (7) and / or receiver (14), characterized in that before each measuring cycle a cleaning of the glass pane (10, 17) is carried out. 22. A method for determining or changing the amount of a in the mold cavity (25) of a die-casting mold (24) to be sprayed water-release agent mixture by means of one of claims 1 to 17 formed device (1), characterized in that the mold cavity (25 ) of the die casting mold (24) is forcibly evacuated via a vent line (31) and that during evacuation the water content of the gas flowing through the vent line (31) is measured or determined by means of the device (1) and that on the basis of the measured or determined values the absolute amount of the water-release agent mixture to be applied is determined for subsequent spraying operations and / or a correction factor for changing the amount of the water-separating agent mixture to be injected is determined.