Detecting device

DESCRIPTION

0002DETECTING DEVICE.

0003Technical field

0004This invention relates to a detecting device and in particular a device for detecting a thermographic image preferably for a metallurgical plant, for example dedicated to die casting.

0005Background art

0006The die casting plants in question generally comprise at least one die, consisting of two half-dies, into which the molten metal is injected. The die is kept closed by hydraulic presses for the entire duration of the injection and is opened at the end of the injection for extracting the cooled and solidified piece.

0007A known device for detecting thermographic images and intended for a metallurgical plant is described, for example, in patent document EP1535034 which relates to a system for controlling technological processes to optimise operating temperatures.

0008The detecting device comprises a radiation sensor, for example comprising a so-called thermal camera, which is directed at a respective half-die.

0009When opening the die, the radiation sensor, which is sensitive in particular to infrared radiation, acquires thermological parameters, in particular by acquiring a thermographic image, of a surface of the half-die.

0010The data acquired is sent to a computerised command and control unit, in communication with the detecting device, by means of corresponding wiring, for subsequent processing.

0011The detecting device comprises a protective case inside of which is housed the thermal camera which is thus protected from environmental disturbances typical of die casting processes. The case is provided with a window, closed for example by a germanium lens, through which the thermal camera is capable of acquiring the above- mentioned thermographic images.

0012The detecting device comprises a shutter or screen of the above- mentioned window to protect it in turn from the ambient disturbances during operation of the plant.

0013The shutter is movable between a first operating configuration wherein the window is open, that is, thermal camera has a clear field of vision for acquiring the thermographic images, and a second operating position wherein the window is closed and protected.

0014The detecting device comprises a pneumatic system in communication with the inside of the case to cool the radiation sensor and in communication with the outside of the case, at the window, in order to keep the closing lens clean.

0015The prior art solutions have some drawbacks.

0016The pneumatic system comprises a unit for distribution of the air in communication with a source of compressed air and a plurality of pipes for feeding air from the distribution unit to the protective case.

0017The distribution unit is located outside the protective case and, to prevent excessive pressure losses, the unit must be positioned relatively close to the case and the sensor, approximately within ten metres, thus limiting the possibility of setting up the control system.

0018The cooling of the radiation sensor is performed by continuously injecting air inside the case with a consequent relatively high consumption of air and a cooling of the sensor which is not entirely optimum.

0019The pipes for supplying the air to the protective case are positioned outside the case and the distribution unit and are therefore exposed to the environmental disturbances and are therefore particularly subject to faults. In this context, the main aim of this invention is to obviate the above- mentioned drawbacks. Disclosure of the invention

0020The aim of the invention is to provide a device for detecting a thermographic image which is more versatile than the prior art solutions and more freely positionable relative to a respective source of air.

0021Another aim of this invention is to provide a device for detecting a thermographic image which is more robust and reliable than prior art solutions.

0022The technical purpose indicated and the aims specified are substantially achieved by a device for detecting a thermographic image according to claim 1.

0023Brief description of drawings

0024Further features and advantages of the invention are more apparent in the non-limiting description which follows of a preferred embodiment of a device for detecting a thermographic image as illustrated in the accompanying drawings, in which:

0025Figure 1 illustrates a first configuration of a detecting device according to this invention, in a schematic perspective view partly in blocks and with some parts cut away for greater clarity;

0026- Figure 2 illustrates the detecting device of Figure 1 in a schematic side view partly in block with some parts cut away for greater clarity;

0027Figure 3 illustrates a second configuration of the detecting device of the previous drawings is a schematic front view and with some parts cut away for greater clarity.

0028Detailed description of preferred embodiments of the invention

0029With reference to the accompanying drawings, the numeral 1 denotes a device for detecting a thermographic image preferably for a metallurgical plant, for example dedicated to die casting.

0030The die casting plants in question generally comprise at least one die, consisting of two half-dies, into which the molten metal is injected. The die is kept closed by hydraulic presses for the entire duration of the injection and is opened at the end of the injection for extracting the cooled and solidified piece.

0031The device 1 is suitable for use in any type of casting process such as, for example, low pressure casting, by gravity, in dies and the like.

0032The device 1 comprises a thermal camera sensitive to infrared radiation, labelled with a corresponding block 2, for acquiring the thermographic images; the thermal camera 2 is of a substantially known type and not described further.

0033The thermal camera 2 is equipped with a focussing device, not illustrated, and the device 1 comprises a drive unit for the focussing device applied to the thermal camera and schematically represented as a block 2a.

0034The device 1 comprises a protective case labelled 3, inside of which is inserted the thermal camera 2.

0035The case 3 is used, in particular, to protect the thermal camera 2 from the ambient disturbances normally present in the plants where the device 1 is preferably used.

0036With particular reference to Figure 3, it should be noted that the protective case 3 has a window 4 through which the thermal camera 2 is able to acquire the thermographic image.

0037The window 4 is preferably protected by a germanium lens suitable for use in situations with very high temperatures.

0038The device 1 comprises a screen 5 located outside the case 3 and movable between a first operating position at which it is superposed on the window 4, illustrated for example in Figure 1 , and a second operating position, illustrated in Figure 3, in which it is shifted from the window 4 to allow the thermal camera 2 to acquire the thermographic image.

0039In the embodiment illustrated, the screen 5 is constrained to the case 3 and is able to rotate about an axis R, perpendicular to the plane of Figure 3, to pass between the first and the second operating positions. The device 1 comprises a pneumatic motor, schematically represented as a block 6, for moving the screen 5 between the above-mentioned first and second operating positions.

0040The device 1 comprises a pneumatic system for supplying compressed air, generically denoted by numeral 7, to supply compressed air inside the case 3 for a plurality of functions described below.

0041The pneumatic system 7 comprises an inlet connector 8 for a connection to a source of compressed air outside the case 3 and schematically represented as a block 9; the connector 8 defines, in practice, an inlet for air compressed into the case 3.

0042The device 1 also comprises a computerised command and control unit, schematically represented as a block 10, configured to command and control the device 1 as described in more detail below.

0043In particular, for example, the unit 10 constitutes a Programmable Logic Controller (PLC) specialised in the management or control of the device 1. The case 3 is equipped with a connector 11 in communication with the computerised unit 9 to allow an exchange of data and commands between the unit 10 and the inside of the case 3.

0044Preferably, the connector 11 is configured for a connection to the computerised unit 9 by an Ethernet line for transmitting thermographic images and a data line for transmitting commands.

0045The computerised unit 10 is in effect in communication with the thermal camera 2 for reception of the thermographic images and, preferably, with the drive unit 2a for any adjustments to the focussing device.

0046Preferably, the device 1 comprises, inside the case 3, an electronic card, schematically represented as a block 10a, in communication with the computerised unit 10 and acting, in a substantially known manner, as interface between the unit 10 and the components to be controlled or with which to communicate inside the case 3. For convenience of description, reference is made below to a direct connection of the separate components with the unit 10 whilst, preferably, the connection is carried out by means of the card 10a.

0047The above-mentioned pneumatic system 7 comprises means 12 for adjusting and distributing air operating inside the protective case 3 and in communication with the connector 8 to receive the compressed air from the source 9.

0048As described in more detail below, the unit 10 is configured to control the adjusting and distributing means 12.

0049The adjusting and distributing means 12 comprise a first solenoid valve 13 in communication with the inlet 8.

0050Downstream of the solenoid valve 13 the pneumatic system comprises a vortex tube 14, or Ranque-Hilsch tube, substantially known and preferably positioned outside the case 3.

0051The vortex tube 14 has an inlet for compressed air in communication with the solenoid valve 13 using a conduit 13a, an outlet of cooled air in communication with the inside of the case 3 and a free outlet for hot air. More specifically, the cooled air outlet is in communication with the inside of the case 3 by means of a conduit 15.

0052The solenoid valve 13 is movable between a first operating configuration at which the vortex tube 14, that is, the conduit 15, is closed or not supplied and a second operating position at which the vortex tube 14, that is, the conduit 15 is open and in communication with the compressed air inlet 8.

0053The solenoid valve 13 basically adjusts the introduction of fresh air inside the case 3 necessary for cooling the thermal camera 2.

0054The thermal camera 2 must be maintained at an operating temperature, that is, at a temperature which remains within a maximum value to avoid measurement errors.

0055Preferably, the device 1 comprises a temperature sensor 16 positioned inside the case 3 and in communication with the computerised unit 10. The computerised unit 10 is configured to control the solenoid valve 13 between the first and second operating configurations according to the temperature value detected by the temperature sensor 16.

0056Advantageously, in this way, the cooling air is supplied inside the case 3 only when necessary; the consumption of air is reduced compared with prior art solutions and operation of the thermal camera 2 is optimised. Preferably, the pressure in the case 3 is maintained at a value higher than the external pressure, that is to say, the case 3 is in over-pressure relative to the outside in such a way as to obstruct an entrance from the outside of contaminating agents.

0057Preferably, the pressure in the case 3 is kept at a predetermined value by a suitably calibrated vent, not illustrated.

0058As shown in Figure 2, the means 12 for adjusting and distributing the air comprise a solenoid valve 17 for opening the screen 5 and a solenoid valve 18 for closing the screen, both in communication with the computerised unit 10.

0059The solenoid valve 17 is in communication with the motor 6 by means of a respective conduit 19 and the solenoid valve 18 is in communication with the motor 6 by means of a respective conduit 20 for supplying compressed air from the inlet 8 to the motor 6.

0060The solenoid valves 17, 18 are movable between a respective first operating configuration, at which the relative conduits 19, 20 are closed, and a respective second operating position at which the relative conduits 19, 20 are open and in communication with the inlet 8.

0061In substantially known manner, the compressed air supplied to the pneumatic motor 6 through the solenoid valve 17 and the conduit 19 determines the opening of the screen 5 and the compressed air supplied to the pneumatic motor 6 through the solenoid valve 18 and the conduit 20 causes the closing of the screen 5. Preferably, the means 12 for adjusting and distributing the air comprise a device for adjusting the speed of opening and closing the screen 5 schematically illustrated with a block 23.

0062The device 23, which can preferably be set up from outside the case 3 intervenes on the pressure difference between the solenoid valves 17 and 18 determining the opening and closing speed of the screen 5.

0063Advantageously, the device 23 is regulated in such a way as to dampen any end stop of the screen 5 in the transit from the open position to the closed configuration and vice versa.

0064In the preferred embodiment illustrated as an example, the pneumatic system 7 comprises the screen 5, that is, the screen 5 defines a conduit for blowing air.

0065The screen 5 has an inlet 5a, preferably at the axis of rotation R, and an outlet 5b at the window 4 considering the screen 5 in the closed position, as schematically shown in Figure 2.

0066The adjusting means 12 comprise a solenoid valve 21 , in communication with the computerised unit 0 and with the compressed air inlet 8.

0067The adjusting means 12 comprise a conduit 22 operating between the solenoid valve 21 , and the inlet 5a in the screen 5.

0068The solenoid valve 21 is movable between a first operating configuration at which the conduit 22 is closed and a second operating position at which the conduit 22 is open and in communication with the inlet 8 and the source 9.

0069The computerised unit 10 is configured to control the solenoid valve 21 between the first and the second operating configurations for blowing air on the window 4 through the outlet 5b in the screen 5.

0070In a preferred embodiment, the solenoid valve 21 is kept always open.

0071In a different embodiment, the solenoid valve 21 is kept open when the screen 5 is in the closed position illustrated in Figure 1.

0072The invention described brings important advantages. The adjustment and distribution of the compressed air actuated by the adjustment means positioned inside the protective case makes the structure as a whole simple.

0073The absence of external pipes makes the solution more reliable since there are fewer external components which can be subject to faults.

0074A simple outer connection is sufficient for connecting with a source of compressed air, which may also be located in a remote position relative to the case 3, since the air adjustment/management is performed inside the case and no longer outside.

0075The external drive unit applied to the thermal camera allows an excellent rationalisation of the spaces inside the case 3 and a general improvement of the cooling.

0076The data and the commands exchanged between the components inside the case and the computerised command and control unit occurs by means of a single cable connected into the corresponding connector.