WO1992020992A1 - Instrument for detecting the presence of a body and rolling mill provided with such an instrument - Google Patents

Instrument for detecting the presence of a body and rolling mill provided with such an instrument Download PDF

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Publication number
WO1992020992A1
WO1992020992A1 PCT/EP1992/001107 EP9201107W WO9220992A1 WO 1992020992 A1 WO1992020992 A1 WO 1992020992A1 EP 9201107 W EP9201107 W EP 9201107W WO 9220992 A1 WO9220992 A1 WO 9220992A1
Authority
WO
WIPO (PCT)
Prior art keywords
housing
gas
instrument according
guide passage
discharge
Prior art date
Application number
PCT/EP1992/001107
Other languages
French (fr)
Inventor
Richard Walter Lea
Rober De Visser
Original Assignee
Hoogovens Groep Bv
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hoogovens Groep Bv filed Critical Hoogovens Groep Bv
Priority to US08/146,006 priority Critical patent/US5408096A/en
Priority to AU17900/92A priority patent/AU655028B2/en
Priority to DE69203867T priority patent/DE69203867T2/en
Priority to EP92910372A priority patent/EP0610199B1/en
Priority to JP4510412A priority patent/JPH07506422A/en
Publication of WO1992020992A1 publication Critical patent/WO1992020992A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/02—Constructional details
    • G01J5/05—Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path
    • G01J5/051—Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path using a gas purge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/0022—Radiation pyrometry, e.g. infrared or optical thermometry for sensing the radiation of moving bodies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/02—Constructional details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/02—Constructional details
    • G01J5/04—Casings
    • G01J5/041—Mountings in enclosures or in a particular environment
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0006—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation

Definitions

  • the invention relates to an instrument for detecting the presence of a body, comprising a detector and a housing in which the detector is accommodated.
  • a detector for detecting the presence of a body
  • a housing for detecting the presence of a body
  • detection methods using other wave ranges are also known.
  • Such a device comprises a housing provided with at least a transmission passage aimed in the direction of the body to be detected suitable for guiding to the detector one or more signals originating from the body.
  • An instrument of this type is used in the practice of continuous casting. Applications in rolling mill installations are also known. In this application the instrument serves to detect the presence of a slab to be rolled out for purposes such as bringing the mill stands of the rolling mill up to the desired angular velocity on time and for making other setting adjustments.
  • Instruments of the kind referred to in the preamble are also used in rolling mills provided with a reversing rolling unit.
  • a reversing rolling unit a slab is rolled out in a number of backward and forward motions into an intermediate product which is suitable for being rolled out to a desired finished rolling thickness in a finishing train. It is important in the use of such a reversing rolling unit to detect not only when the slab to be rolled is approaching the roller but also when it is .leaving the roller. Valuable production time may be saved with this information, given that, for example, detecting the slab leaving the mill stand offers the opportunity of reversing the drive direction of that mill stand as early as possible.
  • the invention provides an instrument for detecting the presence of a body, comprising a detector and a housing, in which the detector is accommodated, said housing being provided with at least one guide passage for transmission to the detector of signals originating from the body, characterised in that the housing is further provided with means for supplying a gas flow and means for discharging at least a part of said flow through the guide passage whereby during operation, at least a part of the gas flow leaves the housing via the guide passage.
  • This system can alleviate the problems above by removing dirt particles which might be present in the housing, these particles being carried out of the housing of the instrument with the cleaning gas via the transmission guide passage.
  • This has the additional advantage that the outflow of cleaning gas can give a clearer path for signals along the transmission passage in the direction of the body to be detected.
  • the housing is provided with a centrifugal separator for separating the cleaning gas into clean and polluted fractions. Furthermore the means of supplying the cleaning gas are connected close to the outer periphery of the centrifugal separator and at least a part of the means for discharging the said cleaning gas is connected adjacent to the centre of the separator.
  • cleaning gas which is itself contaminated.
  • Such gas is present, for example in a hot-rolling mill, in the local compressed air supply network.
  • Such a supply network makes use of surrounding air present in the rolling mill and consequently it is contaminated, among other things, by oil particles suspended in the air.
  • the centrifugal separator proposed the cleaning gas coming from that supply network is split into a pollutant rich fraction and a fraction with a low pollutant level.
  • the fraction contaminated by pollutant e.g. oil
  • the centrifugal separator should be provided, adjacent its centre, with deflector means positioned transverse to the direction of the movement of the cleaning gas for reducing the rotational flow energy in the cleaning gas. This counteracts the strongly circular motion of the cleaning gas as it leaves the centrifugal separator via the transmission passage so that the cleaning gas is conveyed in an essentially straight path along the transmission passage.
  • the transmission passage is provided with a constriction preferably close to its end remote from the detector.
  • a device comprising a first inner element providing a central throughflow conduit which surrounds the transmission passage or an extension of the discharge flow path therefrom, and an outer element at least partially overlapping the inner element, the elements cooperating in defining a slot for a discharge of gas into said conduit in a direction away from the housing and around said passage or said extension.
  • the instrument invented is found to be capable of having a sighting range of approximately half a metre.
  • the sight range is able to extend up to approximately three metres away from the housing. It is believed that this effect is brought about because the gas flow which is generated by means of the device and which surrounds the gas flow out of the transmission passage, protects the latter against turbulence (reversal) caused by dirt and steam in the surroundings.
  • the discharge slot is preferable for the discharge slot to be provided on the end of the device nearer to the housing and to be directed away from the housing towards the central conduit of the device.
  • the gas leaving the discharge slot via the central conduit of the device creates a local pressurised region on the side of the device closest to the housing.
  • the surrounding air from that side is forced along through the central conduit of the device so that a large air movement occurs which surrounds the centrally situated gas flow from the transmission passage and protects it against turbulence.
  • the transmission passage extends through the central conduit of the device and terminates in the region of an end of the central conduit further from the housing.
  • This embodiment is found to give especially good results in terms of the distance from which the instrument may still be used to detect a body. The reason for this is that in this embodiment the central line of sight, resulting from the gas outflow from the transmission passage, remains unchanged for a particularly long time by any turbulence of that flow.
  • An alternative embodiment in accordance with the invention is characterised in that the device is positioned beyond and adjacent to the outlet mouth of the transmission passage. This embodiment is preferable for use in very contaminated surroundings.
  • the instrument is characterised in that the gas discharge means on the housing provides a supply of gas for discharge through the conduit.
  • the means for discharge of the polluted fraction is connected to said device for the supply of said discharge through the conduit. This provides a very refined manner of both creating a useful application of the polluted fraction of the cleaning gas, and, when using a rigid connection, positioning the device relative to the housing as desired.
  • the invention described in the foregoing is as yet described only in terms of application with an instrument which comprises only one detector, though it is not limited to that.
  • the invention is also embodied in an instrument in which the housing is also provided with a signal transmitter and a further transmission passage for directing a signal from the transmitter the body to excite the signal to be received by the detector.
  • the transmission passage forms at least a part of the discharge means for the cleaning gas flow.
  • the invention further relates to a rolling mill for rolling products, for example slabs of steel into strip steel.
  • a rolling mill for rolling products, for example slabs of steel into strip steel.
  • Such rolling mills are frequently provided with means for determining velocities of the products to be rolled.
  • the use of a measuring (recording) roller is known.
  • a problem with this form of measurement is that a high degree of maintenance is required.
  • preventative maintenance needs to be carried out regularly.
  • an accurate, sturdy velocity determining instrument, requiring little maintenance is now created.
  • the means for determining velocity comprises at least two instruments as described in the foregoing and a processing unit. The unit is linked to receive the signals from those instruments for ascertaining the velocity of a product detected by the instruments.
  • the instrument in accordance with the invention has a highly accurate recording spot.
  • the recording spot is understood to be the projection of the line of sight onto the object to be detected.
  • Fig 1 shows the instrument in accordance with the invention in a first embodiment.
  • Fig 2 shows the instrument in accordance with the invention in a second embodiment.
  • Fig 3 shows a cross-section through the centrifugal separator of the instrument in accordance with the invention.
  • Detector (2) is for example an infrared sensitive element which emits an electrical signal if it is activated by infrared radiation.
  • the said electrical signal is led via a cable (4) to further processing equipment.
  • the housing (1) On the side of the lens (3) the housing (1) is provided with a centrifugal separator (5) in which cleaning gas is processed in order firstly for it to help keep clean the surface of the lens (3) and further to help keep clean a transmission guide passage (6) that extends from the lens surface (3) to an end or mouth (7) close to an outer boundary of the housing (1).
  • a centrifugal separator (5) in which cleaning gas is processed in order firstly for it to help keep clean the surface of the lens (3) and further to help keep clean a transmission guide passage (6) that extends from the lens surface (3) to an end or mouth (7) close to an outer boundary of the housing (1).
  • Cleaning gas is supplied into the centrifugal separator (5) via a feeder point (8).
  • a feeder point (8) may be connected, for example, compressed air that may be contaminated.
  • the compressed air supplied via feeder point (8) is brought into a circular motion so that any dirt particles present in the compressed air concentrate on the outer circumference of the centrifugal separator (5) and as a result of this the compressed air moving close to the lens surface (3) is comparatively clean and can clean the lens surface (3) effectively because of the rapid circular motion.
  • the centrifugal separator (5) is provided at its centre with plates (9) (see also Fig 3) which slow down the circular motion of the cleaning gas supplied via feeder point (8) and cause an essentially straight motion of the cleaning gas into the transmission passage (6).
  • the cleaning gas leaves the housing (1) via transmission passage (6) and its mouth (7).
  • the mouth (7) of the transmission passage is also provided with a constriction in order to effect a higher outflow rate near to this outer boundary of the instrument.
  • the instrument is provided with an device (10) comprising a first element (11) and a second element (12) which, acting jointly, define a discharge slot (13).
  • the device (10) is provided with a feeder point (14) for a gas which can leave the device (10) in a direction away from the housing (1) through the discharge slot (13) and via a central conduit (15) of the device (10).
  • the gas that leaves the transmission passage (6) is then surrounded by the gas that leaves the device discharge slot (13) through the central conduit (15) of the device (10). This creates a laminar flow whereby an extended line of sight is formed from the end of transmission passage (6).
  • the line of sight corresponds with the gas outflow from transmission passage (6) and is maintained by the gas flow which surrounds the gas outflow from transmission passage (6), and which is induced by the gas escaping out of discharge slot (13).
  • This is particularly encouraged because the gas that leaves the discharge slot (13) via the central conduit (15) of the device (10) creates a local pressurised region on the side of the device (10) near the housing (1).
  • the surrounding air from that side is forced along through the central conduit (15) of the device (10), so that a large air movement occurs. This surrounds the centrally situated gas flow out of the transmission passage (6) and protects it against turbulence (reversal).
  • Fig 1 shows that the mouth (7) of the transmission guide passage (6) opens out adjacent to the side of the central conduit (15) of the device (10) facing away from the housing (10) .
  • This embodiment is found to be particularly effective for extending the sight passage over a long distance from the end of transmission passage (6).
  • FIG. 2 An alternative embodiment is shown in Fig 2 whereby the mouth (7) of the transmission passage (6) is positioned just in front of the central conduit (15) of the device (10). This embodiment is found to be very effective in highly contaminated surroundings.
  • the feeder point (14) of the device (10) is connected, by means of a rigid connection pipe (16) to the discharge point (17) for the relatively polluted fraction of the cleaning gas originating from the centrifugal separator (5) . This makes it possible to ensure fixed positioning of the device (10) relative to the housing (1).
  • the invention is not limited to the example embodiments described in the foregoing but may be applied with equal success with instruments, which, instead of a single detector (2), are provided at the same time with a signal transmitter and another transmission passage suitable for guiding a signal originating from the transmitter in the direction of the body to be detected.
  • the transmission passage in doing so forms at least a part of the means of discharge of the cleaning gas.
  • the signal is suitable for causing another signal to be generated from the body, this signal being suitable for being detected by the detector.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Optics & Photonics (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Cleaning In General (AREA)
  • Crushing And Grinding (AREA)
  • Centrifugal Separators (AREA)

Abstract

An instrument for detecting the presence of a body, comprising a detector (2) and a housing (1) in which the detector (2) is accommodated. The housing (1) is provided with at least one guide passage (6) for transmission to the detector (2) of one or more signals originating from the body. The housing (1) is also provided with means for supplying a gas flow (8), for example, compressed air, and a means for discharging at least a part of said flow through the guide passage (6) in such a way that, during operation, at least a part of the cleaning gas leaves the housing (1) via the transmission passage (6). At the same time the invention relates to a rolling mill provided with means for determining velocities of the products to be rolled. The means for determining recording velocity comprises at least two of the instruments above and a processing unit which is linked to receive the signals from those instruments for ascertaining the velocity of a product detected by the instruments.

Description

INSTRUMENT FOR DETECTING THE PRESENCE OF A BODY AND ROLLING MILL PROVIDED WITH SUCH AN INSTRUMENT
The invention relates to an instrument for detecting the presence of a body, comprising a detector and a housing in which the detector is accommodated. One known type of instrument is based on the principle of thermal radiation detection from a body. However, detection methods using other wave ranges are also known. Such a device comprises a housing provided with at least a transmission passage aimed in the direction of the body to be detected suitable for guiding to the detector one or more signals originating from the body. An instrument of this type is used in the practice of continuous casting. Applications in rolling mill installations are also known. In this application the instrument serves to detect the presence of a slab to be rolled out for purposes such as bringing the mill stands of the rolling mill up to the desired angular velocity on time and for making other setting adjustments. Instruments of the kind referred to in the preamble are also used in rolling mills provided with a reversing rolling unit. In a reversing rolling unit a slab is rolled out in a number of backward and forward motions into an intermediate product which is suitable for being rolled out to a desired finished rolling thickness in a finishing train. It is important in the use of such a reversing rolling unit to detect not only when the slab to be rolled is approaching the roller but also when it is .leaving the roller. Valuable production time may be saved with this information, given that, for example, detecting the slab leaving the mill stand offers the opportunity of reversing the drive direction of that mill stand as early as possible.
There is a problem in the applications mentioned above in that the instrument has to work in highly contaminated surroundings which adversely affect the operation on the instrument especially in respect of the temperature conditions. Consequently, the known instrument requires a great deal of maintenance. These aggravating conditions include the continual presence of surrounding air saturated with moisture as a result of the cooling water sprayed onto the rollers and the high pressure descaling water for removing the scale from the slab to be rolled. In addition much dirt is present in the surrounding air in the form of iron oxide or oil. Also associated with this is the problem that, in terms of measuring (recording) roller technology, the known instrument for detecting the presence of a body is, in itself, difficult to use in this application, given that the air is saturated with moisture in the form of steam. The invention is intended to offer a solution to the above-mentioned problems and to achieve further advantages which shall be illustrated in the following.
The invention provides an instrument for detecting the presence of a body, comprising a detector and a housing, in which the detector is accommodated, said housing being provided with at least one guide passage for transmission to the detector of signals originating from the body, characterised in that the housing is further provided with means for supplying a gas flow and means for discharging at least a part of said flow through the guide passage whereby during operation, at least a part of the gas flow leaves the housing via the guide passage.
This system can alleviate the problems above by removing dirt particles which might be present in the housing, these particles being carried out of the housing of the instrument with the cleaning gas via the transmission guide passage. This has the additional advantage that the outflow of cleaning gas can give a clearer path for signals along the transmission passage in the direction of the body to be detected.
In a specific aspect of the invention the housing is provided with a centrifugal separator for separating the cleaning gas into clean and polluted fractions. Furthermore the means of supplying the cleaning gas are connected close to the outer periphery of the centrifugal separator and at least a part of the means for discharging the said cleaning gas is connected adjacent to the centre of the separator. This has the advantage that the desired cleaning may be realised using cleaning gas which is itself contaminated. Such gas is present, for example in a hot-rolling mill, in the local compressed air supply network. Such a supply network makes use of surrounding air present in the rolling mill and consequently it is contaminated, among other things, by oil particles suspended in the air.
With the centrifugal separator proposed the cleaning gas coming from that supply network is split into a pollutant rich fraction and a fraction with a low pollutant level. The fraction contaminated by pollutant (e.g. oil) may be discharged elsewhere and the lower pollutant fraction may be used for discharging via the transmission passage. Preferably, at the beginning of the transmission passage the centrifugal separator should be provided, adjacent its centre, with deflector means positioned transverse to the direction of the movement of the cleaning gas for reducing the rotational flow energy in the cleaning gas. This counteracts the strongly circular motion of the cleaning gas as it leaves the centrifugal separator via the transmission passage so that the cleaning gas is conveyed in an essentially straight path along the transmission passage. In a preferred embodiment of the instrument in accordance with the invention the transmission passage is provided with a constriction preferably close to its end remote from the detector. Thus the cleaning gas attains its highest exit rate at the outer end of the transmission passage and consequently the entry of dirt into the housing is further impeded.
In another aspect of the invention there is provided a device comprising a first inner element providing a central throughflow conduit which surrounds the transmission passage or an extension of the discharge flow path therefrom, and an outer element at least partially overlapping the inner element, the elements cooperating in defining a slot for a discharge of gas into said conduit in a direction away from the housing and around said passage or said extension.
Surprisingly, it has been found that the line of sight for the outflow of the cleaning gas from the transmission passage, becomes greatly extended. In this way even without such an device the instrument invented is found to be capable of having a sighting range of approximately half a metre. However, when the aforementioned device is used it is found that the sight range is able to extend up to approximately three metres away from the housing. It is believed that this effect is brought about because the gas flow which is generated by means of the device and which surrounds the gas flow out of the transmission passage, protects the latter against turbulence (reversal) caused by dirt and steam in the surroundings. It is preferable for the discharge slot to be provided on the end of the device nearer to the housing and to be directed away from the housing towards the central conduit of the device. Thus the gas leaving the discharge slot via the central conduit of the device creates a local pressurised region on the side of the device closest to the housing. As a result of this the surrounding air from that side is forced along through the central conduit of the device so that a large air movement occurs which surrounds the centrally situated gas flow from the transmission passage and protects it against turbulence.
In a preferred embodiment of the invention the transmission passage extends through the central conduit of the device and terminates in the region of an end of the central conduit further from the housing. This embodiment is found to give especially good results in terms of the distance from which the instrument may still be used to detect a body. The reason for this is that in this embodiment the central line of sight, resulting from the gas outflow from the transmission passage, remains unchanged for a particularly long time by any turbulence of that flow. An alternative embodiment in accordance with the invention is characterised in that the device is positioned beyond and adjacent to the outlet mouth of the transmission passage. This embodiment is preferable for use in very contaminated surroundings. In another aspect of the invention the instrument is characterised in that the gas discharge means on the housing provides a supply of gas for discharge through the conduit. It is then of particular advantage if the means for discharge of the polluted fraction is connected to said device for the supply of said discharge through the conduit. This provides a very refined manner of both creating a useful application of the polluted fraction of the cleaning gas, and, when using a rigid connection, positioning the device relative to the housing as desired.
The invention described in the foregoing is as yet described only in terms of application with an instrument which comprises only one detector, though it is not limited to that. The invention is also embodied in an instrument in which the housing is also provided with a signal transmitter and a further transmission passage for directing a signal from the transmitter the body to excite the signal to be received by the detector. The transmission passage forms at least a part of the discharge means for the cleaning gas flow.
The invention further relates to a rolling mill for rolling products, for example slabs of steel into strip steel. Such rolling mills are frequently provided with means for determining velocities of the products to be rolled. The use of a measuring (recording) roller is known. However a problem with this form of measurement is that a high degree of maintenance is required. In order to maintain sufficient accuracy of the velocity recording and in order to counteract the slip of the recording roller, preventative maintenance needs to be carried out regularly. In accordance with the invention an accurate, sturdy velocity determining instrument, requiring little maintenance, is now created. The means for determining velocity comprises at least two instruments as described in the foregoing and a processing unit. The unit is linked to receive the signals from those instruments for ascertaining the velocity of a product detected by the instruments. This application is made possible because the instrument in accordance with the invention has a highly accurate recording spot. Here the recording spot is understood to be the projection of the line of sight onto the object to be detected. The invention will now be described, by way of example, with reference to the accompanying drawings.
Fig 1 shows the instrument in accordance with the invention in a first embodiment.
Fig 2 shows the instrument in accordance with the invention in a second embodiment.
Fig 3 shows a cross-section through the centrifugal separator of the instrument in accordance with the invention.
Corresponding reference numerals in the figures indicate corresponding parts of the instrument. In Fig 1 and 2 an instrument is shown comprising a housing (1), a detector (2) in the housing (1), which detector (2) is mounted behind a lens (3). Detector (2) is for example an infrared sensitive element which emits an electrical signal if it is activated by infrared radiation. The said electrical signal is led via a cable (4) to further processing equipment.
On the side of the lens (3) the housing (1) is provided with a centrifugal separator (5) in which cleaning gas is processed in order firstly for it to help keep clean the surface of the lens (3) and further to help keep clean a transmission guide passage (6) that extends from the lens surface (3) to an end or mouth (7) close to an outer boundary of the housing (1).
Cleaning gas is supplied into the centrifugal separator (5) via a feeder point (8). To this feeder point (8) may be connected, for example, compressed air that may be contaminated. In the centrifugal separator the compressed air supplied via feeder point (8) is brought into a circular motion so that any dirt particles present in the compressed air concentrate on the outer circumference of the centrifugal separator (5) and as a result of this the compressed air moving close to the lens surface (3) is comparatively clean and can clean the lens surface (3) effectively because of the rapid circular motion.
Near the transmission passage (6) the centrifugal separator (5) is provided at its centre with plates (9) (see also Fig 3) which slow down the circular motion of the cleaning gas supplied via feeder point (8) and cause an essentially straight motion of the cleaning gas into the transmission passage (6). The cleaning gas leaves the housing (1) via transmission passage (6) and its mouth (7). Preferably the mouth (7) of the transmission passage is also provided with a constriction in order to effect a higher outflow rate near to this outer boundary of the instrument.
At the same time the instrument is provided with an device (10) comprising a first element (11) and a second element (12) which, acting jointly, define a discharge slot (13). The device (10) is provided with a feeder point (14) for a gas which can leave the device (10) in a direction away from the housing (1) through the discharge slot (13) and via a central conduit (15) of the device (10). The gas that leaves the transmission passage (6) is then surrounded by the gas that leaves the device discharge slot (13) through the central conduit (15) of the device (10). This creates a laminar flow whereby an extended line of sight is formed from the end of transmission passage (6). The line of sight corresponds with the gas outflow from transmission passage (6) and is maintained by the gas flow which surrounds the gas outflow from transmission passage (6), and which is induced by the gas escaping out of discharge slot (13). The belief is that this is particularly encouraged because the gas that leaves the discharge slot (13) via the central conduit (15) of the device (10) creates a local pressurised region on the side of the device (10) near the housing (1). As a result the surrounding air from that side is forced along through the central conduit (15) of the device (10), so that a large air movement occurs. This surrounds the centrally situated gas flow out of the transmission passage (6) and protects it against turbulence (reversal).
Fig 1 shows that the mouth (7) of the transmission guide passage (6) opens out adjacent to the side of the central conduit (15) of the device (10) facing away from the housing (10) . This embodiment is found to be particularly effective for extending the sight passage over a long distance from the end of transmission passage (6).
An alternative embodiment is shown in Fig 2 whereby the mouth (7) of the transmission passage (6) is positioned just in front of the central conduit (15) of the device (10). This embodiment is found to be very effective in highly contaminated surroundings.
The feeder point (14) of the device (10) is connected, by means of a rigid connection pipe (16) to the discharge point (17) for the relatively polluted fraction of the cleaning gas originating from the centrifugal separator (5) . This makes it possible to ensure fixed positioning of the device (10) relative to the housing (1).
The invention is not limited to the example embodiments described in the foregoing but may be applied with equal success with instruments, which, instead of a single detector (2), are provided at the same time with a signal transmitter and another transmission passage suitable for guiding a signal originating from the transmitter in the direction of the body to be detected. The transmission passage in doing so forms at least a part of the means of discharge of the cleaning gas. The signal is suitable for causing another signal to be generated from the body, this signal being suitable for being detected by the detector.

Claims

1. An instrument for detecting the presence of a body, comprising a detector (2) and a housing (1), in which the detector (2) is accommodated, said housing (1) being provided with at least one guide passage (6) for transmission to the detector (2) of signals from the body, characterised in that the housing (1) is further provided with means for supplying a gas flow (8), and means for directing at least a part of said flow through the guide passage (6) such that, during operation, at least a part of the gas flow leaves the housing (1) via the guide passage (6).
2. An instrument according to claim 1, wherein the housing (1) is provided with a centrifugal separator (5) for separating the gas into clean and polluted fractions, and the gas supplying means (8) is connected close to the outer periphery of the centrifugal separator (5), and the gas directing means comprises a connection adjacent the centre of said separator (5).
3. An instrument according to claim 2, wherein the centrifugal separator (5) is provided adjacent its centre with deflector means (9) positioned transverse to the direction of flow of the gas for reducing the rotational flow energy of the gas.
4. An instrument according to any one of claims 1,2 or 3, wherein the guide passage (6) is provided with a constriction close to its end (7) remote from the detector (2).
5. An instrument according to any one of the preceding claims wherein a device (10) comprising a first inner element (11) providing a central throughflow conduit (15) which surrounds the guide passage (6) or an extension of the discharge flow path therefrom, and an outer element (12) at least partially overlapping the inner element (11), the elements cooperating in defining a slot (13) for a discharge of gas into said conduit in a direction away from the housing (1) and around said passage (6) or said extension.
6. An instrument according to claim 5, wherein the discharge slot (13) is provided on an end of the device nearer to the housing (1) and is directed away from the housing (1) and towards the central conduit (15) of the device.
7. An instrument according to claim 5 or claim 6, wherein the guide passage (6) extends through the central conduit (15) of the device and terminates in the region of an end of the central conduit further from the housing.
8. An instrument according to claim 5 or claim 6, wherein the device (10) is positioned beyond and adjacent to an outlet mouth (7) of the guide passage (6).
9. An instrument according to any one of claims 5 to 8 wherein the gas flow directing means are provided for directing a further part of said housing gas flow for said discharge through said slot (13).
10. An instrument according to claim 2 together with claim 9 wherein means for the discharge of the polluted fraction is connected to said device (10) for said discharge of said fraction through the slot (13).
11. An instrument according to any one of the preceding claims wherein the housing (1) is provided with a signal transmitter and a further guide passage for directing a signal from the transmitter towards the body to excite said signal to be received by the detector, said further passage forming at least a part of the directing means for the gas flow.
12. A rolling mill having means for determining the velocity of a product to be rolled, including at least two instruments in accordance with any one of claims 1 to 11 and a processing unit which is linked to receive the signals from those instruments for ascertaining the velocity of a product detected by the instruments. AMENDED CLAIMS
[received by the International Bureau on 21 September 1992 (21.09.92); original claims 1-12 replaced by amended claims 1-9 (3 pages)]
1. An instrument for detecting the presence of a body, comprising a detector (2) and a housing (1), in which the detector (2) is accommodated, said housing (1) being provided with at least one guide passage (6) for transmission to the detector (2) of signals from the body, and with means for supplying a gas flow (8) , and means for directing at least a part of said flow through the guide passage (6) such that, during operation, at least a part of the gas flow leaves the housing (1) via the guide passage (6) , characterised in that it is provided with a device (10) comprising a first inner element (11) providing a central throughflow conduit (15) which surrounds the guide passage (6) or an extension of the discharge flow path therefrom, and an outer element (12) at least partially overlapping the inner element (11) , the elements cooperating in defining a slot (13) for a discharge of gas into said conduit in a direction away from the housing (1) and around said passage (6) or said extension.
2. An instrument according to claim 1, wherein the discharge slot (13) is provided on an end of the device nearer to the housing (1) and is directed away from the housing (1) and towards the central conduit (15) of the device.
3. An instrument according to claim 1 or claim 2, wherein the guide passage (6) extends through the central conduit (15) of the device and terminates in the region of an end of the central conduit further from the housing. 4. An instrument according to claim 1 or claim 2, wherein the device (10) is positioned beyond and adjacent to an outlet mouth (7) of the guide passage (6).
5. An instrument according to any one of claims 1-4 wherein the gas flow directing means are provided for directing a further part of said housing gas flow for said discharge through said slot (13).
6. An instrument according to any one of claims 1-5 provided with a centrifugal separator (5) for separating the gas into a clean and a polluted fraction, and wherein the gas supplying means (8) is connected close to the outer periphery of the centrifugal separator (5), and the gas directing means comprises a connection adjacent the centre of said separator (5), wherein means for the discharge of the polluted fraction is connected to said device (10) for said discharge of said fraction through said slot (13).
7. An instrument according to claim 6, wherein the centrifugal separator (5) is provided adjacent its centre with deflector means (9) positioned transverse to the direction of flow of the gas for reducing the rotational flow energy of the gas.
8. An instrument according to any one of the preceding claims wherein the housing (1) is provided with a signal transmitter and a further guide passage for directing a signal from the transmitter towards the body to excite said signal to be received by the detector, said further passage forming at least a part of the directing means for the gas flow.
9. A rolling mill having means for determining the velocity of a product to be rolled, including at least two instruments in accordance with any one of the preceding claims and a processing unit which is linked to receive the signals from those instruments for ascertaining the velocity of a product detected by the instruments.
PCT/EP1992/001107 1991-05-13 1992-05-11 Instrument for detecting the presence of a body and rolling mill provided with such an instrument WO1992020992A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US08/146,006 US5408096A (en) 1991-05-13 1992-05-11 Instrument for a centrifugal separator for detecting the presence of a body and rolling mill provided with such an instrument
AU17900/92A AU655028B2 (en) 1991-05-13 1992-05-11 Instrument for detecting the presence of a body and rolling mill provided with such an instrument
DE69203867T DE69203867T2 (en) 1991-05-13 1992-05-11 INSTRUMENT FOR DETECTING THE PRESENCE OF A BODY.
EP92910372A EP0610199B1 (en) 1991-05-13 1992-05-11 Instrument for detecting the presence of a body
JP4510412A JPH07506422A (en) 1991-05-13 1992-05-11 Equipment for detecting the presence of objects and rolling mills equipped with such equipment

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL9100822A NL9100822A (en) 1991-05-13 1991-05-13 INSTRUMENT FOR DETERMINING THE PRESENCE OF A BODY AND ROLLING MILL PROVIDED WITH SUCH AN INSTRUMENT.
NL9100822 1991-05-13

Publications (1)

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WO1992020992A1 true WO1992020992A1 (en) 1992-11-26

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EP (1) EP0610199B1 (en)
JP (1) JPH07506422A (en)
AU (1) AU655028B2 (en)
CA (1) CA2102614A1 (en)
DE (1) DE69203867T2 (en)
NL (1) NL9100822A (en)
WO (1) WO1992020992A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0685717A1 (en) * 1994-06-03 1995-12-06 Land Instruments International Limited Improvements relating to radiation thermometers

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE9602023L (en) * 1996-05-28 1997-11-29 Eije Fernstroem Methods and apparatus for preventing unintentional influence of sensing sensors
US8767199B2 (en) * 2010-10-15 2014-07-01 Infrared Laboratories, Inc. Inspection system utilizing solid immersion lenses

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE895161C (en) * 1941-11-08 1953-11-02 Thyssen Huette Ag Device for measuring the temperature of the steel bath in the blowing converter
FR1432792A (en) * 1965-02-12 1966-03-25 Thomson Houston Comp Francaise Device for protecting a surface against dirt and corrosion
GB1114682A (en) * 1966-02-07 1968-05-22 British Iron Steel Research Protective heads for thermal radiation receivers such as radiation pyrometers
DE1497581A1 (en) * 1966-09-27 1969-04-03 Siemens Ag Device for preventing dust deposits on the lenses of optical devices
US3824015A (en) * 1971-10-29 1974-07-16 Siderurgie Fse Inst Rech Method of, and apparatus for, the optical measurement of the speed at a moving product
DE3312031A1 (en) * 1982-04-05 1983-10-06 Elitex Zavody Textilniho Air screen of a radiation thermometer
US4738528A (en) * 1987-04-03 1988-04-19 General Electric Co. Pyrometer vortex purge air cleaning system with center masked pyrometer lens
US4784491A (en) * 1986-06-03 1988-11-15 General Electric Company System to protect optics against dirty environments
DE8815494U1 (en) * 1988-12-14 1989-03-23 I F M Internationale Fluggeräte und Motoren GmbH, 6940 Weinheim Device for detecting glowing rolled goods
US5000580A (en) * 1989-08-18 1991-03-19 Texaco Inc. Apparatus and method for measuring temperatures inside process vessels containing a hostile environment

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1251246B (en) * 1991-08-27 1995-05-05 Sie Systems Spa DEVICE FOR DETECTION OF THE PRESENCE AND QUALITY OF THE FLAME THROUGH THE COLLECTION AND ANALYSIS OF ELECTROMAGNETIC RADIATIONS OF DIFFERENT WAVELENGTH
US5180921A (en) * 1991-11-18 1993-01-19 National Research Council Of Canada Method and apparatus for monitoring the temperature and velocity of plasma sprayed particles

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE895161C (en) * 1941-11-08 1953-11-02 Thyssen Huette Ag Device for measuring the temperature of the steel bath in the blowing converter
FR1432792A (en) * 1965-02-12 1966-03-25 Thomson Houston Comp Francaise Device for protecting a surface against dirt and corrosion
GB1114682A (en) * 1966-02-07 1968-05-22 British Iron Steel Research Protective heads for thermal radiation receivers such as radiation pyrometers
DE1497581A1 (en) * 1966-09-27 1969-04-03 Siemens Ag Device for preventing dust deposits on the lenses of optical devices
US3824015A (en) * 1971-10-29 1974-07-16 Siderurgie Fse Inst Rech Method of, and apparatus for, the optical measurement of the speed at a moving product
DE3312031A1 (en) * 1982-04-05 1983-10-06 Elitex Zavody Textilniho Air screen of a radiation thermometer
US4784491A (en) * 1986-06-03 1988-11-15 General Electric Company System to protect optics against dirty environments
US4738528A (en) * 1987-04-03 1988-04-19 General Electric Co. Pyrometer vortex purge air cleaning system with center masked pyrometer lens
DE8815494U1 (en) * 1988-12-14 1989-03-23 I F M Internationale Fluggeräte und Motoren GmbH, 6940 Weinheim Device for detecting glowing rolled goods
US5000580A (en) * 1989-08-18 1991-03-19 Texaco Inc. Apparatus and method for measuring temperatures inside process vessels containing a hostile environment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0685717A1 (en) * 1994-06-03 1995-12-06 Land Instruments International Limited Improvements relating to radiation thermometers
US5655837A (en) * 1994-06-03 1997-08-12 Land Instruments International Limited Radiation thermometers

Also Published As

Publication number Publication date
NL9100822A (en) 1992-12-01
CA2102614A1 (en) 1992-11-14
JPH07506422A (en) 1995-07-13
DE69203867D1 (en) 1995-09-07
AU1790092A (en) 1992-12-30
EP0610199B1 (en) 1995-08-02
US5408096A (en) 1995-04-18
EP0610199A1 (en) 1994-08-17
DE69203867T2 (en) 1995-12-21
AU655028B2 (en) 1994-12-01

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