EP0070115A2 - Billet heating furnace - Google Patents
Billet heating furnace Download PDFInfo
- Publication number
- EP0070115A2 EP0070115A2 EP82303345A EP82303345A EP0070115A2 EP 0070115 A2 EP0070115 A2 EP 0070115A2 EP 82303345 A EP82303345 A EP 82303345A EP 82303345 A EP82303345 A EP 82303345A EP 0070115 A2 EP0070115 A2 EP 0070115A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- furnace
- billets
- furnace chamber
- burner
- chamber
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
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Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/663—Bell-type furnaces
- C21D9/675—Arrangements of charging or discharging devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
- F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace
- F27B9/22—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace on rails, e.g. under the action of scrapers or pushers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
- F27B9/38—Arrangements of devices for charging
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
- F27B9/40—Arrangements of controlling or monitoring devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
- F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
- F27B9/36—Arrangements of heating devices
- F27B2009/3607—Heaters located above the track of the charge
- F27B2009/3615—Burner in the ceiling directed vertically downwards
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D1/0003—Linings or walls
- F27D1/0006—Linings or walls formed from bricks or layers with a particular composition or specific characteristics
- F27D1/0009—Comprising ceramic fibre elements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D2003/0001—Positioning the charge
- F27D2003/0002—Positioning the charge involving positioning devices, e.g. buffers, buffer zones
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D19/00—Arrangements of controlling devices
- F27D2019/0006—Monitoring the characteristics (composition, quantities, temperature, pressure) of at least one of the gases of the kiln atmosphere and using it as a controlling value
- F27D2019/0018—Monitoring the temperature of the atmosphere of the kiln
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
- F27D2021/0057—Security or safety devices, e.g. for protection against heat, noise, pollution or too much duress; Ergonomic aspects
- F27D2021/0092—Security or safety devices, e.g. for protection against heat, noise, pollution or too much duress; Ergonomic aspects against a jam in the transport line or a production interruption
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D3/02—Skids or tracks for heavy objects
- F27D3/022—Skids
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27M—INDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
- F27M2001/00—Composition, conformation or state of the charge
- F27M2001/15—Composition, conformation or state of the charge characterised by the form of the articles
- F27M2001/1539—Metallic articles
- F27M2001/1547—Elongated articles, e.g. beams, rails
- F27M2001/1552—Billets, slabs
Definitions
- the aim of the present invention is to provide a billet heating furnace of the enclosed slid type which can be made very much smaller and can be operated safely, reliably, and very much more efficiently than existing enclosed skid billet heating furnaces.
- the air and gas supplies to the burner are provided with sensors and the burner is arranged to be rendered inoperative if either the air or gas pressure is below a predetermined minimum. Consequently, not only can the burner not be started without sufficient gas and air pressure, but the burner will automatically shut down, for example by closure of a valve controlling the gas supply, if there is an appreciable fall in gas or air pressure during operation of the furnace.
- the cylinder 67 is arranged to be operated to open the slide 64 automatically at the same time as the burners are shut down, and there is also means (not shown) for manually actuating the reject cylinder 67. ⁇ In either case, however, the slide can be closed only by manual actuation of a switch (not shown) so that, on start-up or after any stoppage, billets will not be supplied to the press from the furnace until the operator decides to close the slide 64, that is when he is satisfied that the billets are being heated to the required temperature.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
- Tunnel Furnaces (AREA)
Abstract
Description
- This invention relates to gas fired furnaces for heating metal billets in preparation for a hot forming operation to be carried out on the billets, and has been developed primarily for the purpose of heating brass billets prior to stamping in a press.
- Automatic presses in the brass stamping industry require a regular supply of billets at a substantially uniform stamping temperature, and for this purpose it is usual for the billets to be fed to the press from a train which is pushed step by step through a furnace by a feeding mechanism which adds billets to the rear of the train in synchronism with the stamping rate of the press. The furnace is intended to heat each billet to the required stamping temperature during its passage through the furnace, but the furnaces which have been used so far have not proved entirely satisfactory.
- In one type of furnace which has been used, the train of billets is pushed along a cast heat resistant skid at the base of a V-shaped refractory setting down one side of which a row of air blast gas burner nozzles fire onto the billets on the skid. This open hearth type of furnace has a very low thermal efficiency, and if the train of billets through the furnace is stopped for any reason, for example because of a press stoppage, there can be a problem with billets melting due to the high heat capacity of the skid and the refractory setting. Furthermore, control of the furnace is mainly manual and therefore requires frequent attention, and the working environment is poor due to flame splash from the skid.
- In another type of gas fired furnace which has been used, known as the enclosed skid type, the train of billets is moved along a skid extending through an enclosed furnace chamber lined with a heat resistant material. In existing furnaces of this type the lining is of refractory material, and because of its high thermal mass there is still a problem with a tendency for the billets to melt during stoppages in the flow of billets through the furnace if the operating temperature of the furnace is too high. To avoid this problem, such furnaces are controlled so that the operating temperature is maintained below the billet melting temperature and only just above the stamping temperature. However, such a method of operation is inefficient since the temperature differential between the furnace the the billets at the outlet end of the furnace is small and the heat transfer rate is therefore very low. Consequently the furnace needs to be relatively large.
- The aim of the present invention is to provide a billet heating furnace of the enclosed slid type which can be made very much smaller and can be operated safely, reliably, and very much more efficiently than existing enclosed skid billet heating furnaces.
- To this end, according to the invention, a furnace of the enclosed skid type for heating billets to a predetermined temperature which is below their melting temperature as the billets are moved at a predetermined rate along the skid through the furnace chamber comprises a billet feed mechanism adjacent the inlet end of the furnace chamber for regularly feeding billets onto and along the skid, a gas burner for raising the temperature in the furnace chamber to an operating temperature which is higher than the melting temperature of the billets, burner control means for maintaining the operating temperature substantially constant, a delivery path adjacent the outlet end of the furnace chamber for receiving billets as they leave the chamber, a billet detector arranged to detect an interruption of the regular flow of billets from the furnace chamber and to shut down the burner when such an interruption is detected, and a reject mechanism for diverting billets from the delivery path and operative if the burner is shut down, the thermal mass of the skid and the heat resistant lining of the furnace chamber being such that, after the burner is shut down, the temperature in the furnace chamber falls to below the melting temperature of the billets before the temperature of any billet stationary in the chamber can rise to the melting temperature.
- By using a light weight heat resistant skid and a low thermal mass lining in the furnace chamber, and arranging for the burner to shut down immediately on detection of any interruption in the regular flow of billets leaving the furnace chamber, the furnace may be operated at a considerably higher temperature than conventional enclosed skid furnaces. This gives a greater temperature differential between the furnace chamber and the billets, which increases the heat transfer rate and therefore increases the furnace efficiency. For example, in one form of furnace in accordance with the invention which has been designed for heating brass billets and in which the skid is made from Inconel 600 sheet and the furnace lining comprises layers of ceramic fibre board, the furnace can be operated at a temperature of about 1200oC, which is substantially above the melting temperature of brass (8600), to produce a billet temperature or about 750°C at the outlet of the furnace chamber. Provided the time taken for the billet detector to detect an interruption in the flow of billets from the furnace and to shut down the burner is not too long, the temperature in the furnace chamber will drop from 12000C to below 860°C before the temperature of the billets in the chamber rises to melting point.
- The billet detector may comprise a pneumatic sensor which produces a pulse in response to the passage of a billet down a delivery chute which forms at least part of the delivery path, and a timer which is reset by each pulse from the sensor and which is operative to shut down the burner if not reset by a pulse within a predetermined time after the previous pulse. The sensitivity of the detector is therefore determined by the setting of the timer. The timer may be a pneumatic device comprising a reservoir having an orifice bleed and a pressure switch arranged to produce an electrical output signal if the pressure in the reservoir falls to a predetermined low value, the reservoir pressure being restored to a predetermined high value in response to each pulse from the sensor.
- An interruption of the regular flow of billets down the delivery chute may be caused by one or more billets coming off the skid in the furnace chamber, by a fault in the feed mechanism, or by stoppage of the press when the billets are being fed to an automatic press and the press stroke is used to index the operation of the feed mechanism. Whatever the reason for the interruption however, it is detected almost immediately and the burner is automatically shut down. In addition, the reject mechanism is automatically actuated, not so much for the purpose of preventing the supply to the press of any billets immediately following the interruption since it is preferable that burner shut down will also be accompanied automatically by stoppage of the feed mechanism, but primarily for ensuring that when the furnace is started up again the billets are automatically rejected until the furnace reaches its operating temperature and the billets leaving the furnace chamber are at the required temperature. For this purpose, once the reject mechanism has been actuated, it is arranged to remain operative until deactivated by an operator who determines when the billets are ready to be supplied through the delivery chute to the press.
- The reject mechanism may be located upstream or downstream of the billet detector in the delivery path, but preferably it is located upstream, comprising a reject chute and a gate which is movable, for example by means of a pneumatic cylinder, between an open position (reject mechanism actuated) in which the billet leaving the furnace chamber are arranged to drop down the reject chute instead of the delivery chute, and a closed position in which the billets leaving the furnace chamber are arranged to pass the reject chute and to drop down the delivery chute.
- The burner is preferably of a high velocity premix type which is fitted in the top of the furnace chamber and which is supplied with an air/gas mixture by a standard air blast control train. The gas/air mixture is ignited within the burner by means of an electrical ignition probe and combustion takes place inside a burner quarl, the hot combustion products being ejected from the quarl into the furnace chamber through a converging slot directly above and in line with the skid. The furnace may of course be provided with more than one such burner depending on the length of the furnace chamber required, having regard to the size of billets which are to be heated.
- The burner control means is preferably low fire biassed so that the burner always lights at low fire and then drives to high fire, and when the furnace operating temperature is reached this is maintained substantially constant, preferably by modulating an air valve in the air blast train feeding the burner, in response to a temperature sensor in the furnace chamber. This may be a thermocouple mounted under the skid.
- Preferably the air and gas supplies to the burner are provided with sensors and the burner is arranged to be rendered inoperative if either the air or gas pressure is below a predetermined minimum. Consequently, not only can the burner not be started without sufficient gas and air pressure, but the burner will automatically shut down, for example by closure of a valve controlling the gas supply, if there is an appreciable fall in gas or air pressure during operation of the furnace.
- Preferably the furnace chamber comprises two sections, a lower section in which the skid is mounted, and an upper section in which the burner is mounted and which is hinged to the lower section so that it can be raised and lowered, for example by means of a pneumatic cylinder, to open and close the furnace chamber. With this arrangement the furnace in accordance with the invention combines the ease of access of an open hearth type furnace with the higher efficiency of an enclosed skid furnace. As a safety precaution, the furnace is preferably provided with a switch which is open to render the burner inoperative if the furnace chamber is not closed.
- A particular example of a furnace in accordance with the invention will now be described with reference to the accompanying drawings, in which:-
- Figure 1 is a side elevation of the furnace;
- Figure 2 is a plan view of the furnace;
- Figure 3 is an end elevation of the furnace; and,
- Figure 4 is a cross section through the furnace casing taken on the line IV-IV in Figure 1.
- The furnace shown in the drawings has been designed for heating small brass billets to a temperature of approximately 7500C for supply to an automatic stamping press (not shown).
- The furnace comprises a steel casing which is split into two parts, a lower or
base part 1 comprising a foldedchannel section 3 andend plates section 3, and an upper orlid part 2 comprising a folded invertedchannel section 6 havingend plates lower casing part 1 is fixed on a suitable support, indicated generally at 9, and theupper part 2 is hinged to thelower part 1 by means of ahinge pin 10 which extends along one side of the casing and is journalled in laterally extending flanges of theend plates lid 2 about thehinge pin 10 by means of apneumatic cylinder 11 which has its lower end pivotally mounted on apost 12 fixed to thelower casing part 1 and which has itspiston rod 13 pivotally attached to alever 14 fixed to thelid 2 approximately midway along its length. A hook shapedcatch 15 provided with a manipulatinghandle 16 is pivotally attached to thelever 14 so that when thelid 2 is opened it can be locked in the open position by engaging the hooked end of thecatch 15 below aretaining pin 18 fixed between a pair ofanchor plates 19 which in turn are fixed to the side of thebase part 1. One of theanchor plates 19 also mounts amicroswitch 20 which detects when thelid 2 is opened and which is closed only when the casing is fully closed. It is to be noted that both theanchor plates 19 and thelever 14 are provided with bearing holes through which thehinge pin 10 passes and which provide additional support for the hinge pin. - As shown in Figure 4, the lower and
upper parts ceramic fibre material 21 so that when thelid 2 is closed a relatively small rectangularly sectioned, longitudinally extendingfurnace chamber 22 is formed substantially centrally within the casing by means of a channel in the lining of thelower casing part 1. Theceramic fibre lining 21 of thelower part 1 compriseslayers 23 or 12600C grade ceramic fibre board covering theend walls channel section 3 as shown in Figure 4, and alayer 24 of 16000C grade ceramic fibre moist felt lining the inner and upper surfaces of thelayers 23 to form a strong high temperature resistant lining to thefurnace chamber 22. Theceramic fibre lining 21 in theupper part 2 is formed by alayer 25 of 12600C grade ceramic fibre blanket,layers 26 of 1260°C grade ceramic fibre board, and an outermost layer 27 (i.e. faeing the furnace chamber 22) of 1600°C grade ceramic fibre moist felt, the layers being cut to fit around a pair ofgas burner units 28 which are mounted in thelid part 2 towards one end of the casing, and also around a flue opening 29 at the opposite end of the casing. The ceramic fibre moist feltlayers furnace chamber 22 is sealed by means of aceramic fibre blanket 30 fitted in thelower part 2. - Set centrally into the base of the
furnace chamber 22 is a V-shaped skid 31 which extends longitudinally through the furnace chamber, extending through an inlet opening 32 at one end of thelower casing part 1 and through an outlet opening 33 at the other end of thelower part 1. Theskid 31 is folded to a 90 degree angle from a strip of Inconel 600, which is a light-weight heat resistant material, and is fixed at the outlet end of thecasing part 1 so that it is free to expand at the inlet end where an overlappinginlet section 34 is provided to accommodate such movement of theskid 31. - The
burners 28 mounted in thelid section 2 of the furnace casing are of a high velocity premix type which are fed with an air/gas mixture by a standard air blast control train comprising a commonair supply duct 35 which branches to supply a pair ofinjectors 36 which entrain gas supplied to each from agas supply duct 37. Theair supply duct 35 contains a low pressure sensor (not shown) and a modulating valve (also not shown) for controlling the air supply as described later. Thegas supply duct 37 also contains a low pressure sensor (not shown), and is provided with a control valve (also not shown) for shutting off the gas supply to shut down the burners. - The gas/air mixture is conducted from the
injectors 36 to theburners 28 bypipes 38. Each of theburners 28 comprises a refractory lined top section 39 which is mounted on the top of thecasing part 2 and which carries a row of gas/air mixing tubes 40 and aspark ignition probe 41, and alower section 42 which is fitted within the linedlid part 2 of the furnace casing and which comprises a quarl cast from fused alumina refractory material. The gas and air which is supplied to eachburner 28 is directed downwards through the mixing tubes 40 for combustion in the quarl of thelower section 42, the hot combustion products entering thfurnace chamber 22 through aconverging slot outlet 43 from the quarl which is directly above and in line with theskid 31. As mentioned earlier, theburners 28 are located towards the outlet end of thefurnace chamber 22, and the hot combustion products entering thechamber 22 therefore move along the chamber towards the inlet end where they are arranged to exit from the chamber through the flue opening 29. - In operation of the present example, the
burners 28 will bring thefurnace chamber 22 to its operating temperature of approximately 12000C within two minutes, the temperature being measured by a thermo-couple (not shown) which is located under theskid 31. When the operating temperature is reached, it is maintained substantially constant by means of a controller (not shown) which is responsive to the thermocouple and which operates the modulating valve in theair supply duct 35, thereby controlling the air/gas supply to the burners. - It is to be noted that the part of the air/gas supply train to the
burners 28 shown in the drawings is fixed to thelid section 2 of the furnace casing by means ofbrackets clamps 46, movement of the train when thelid section 2 is opening and closed being accommodated by flexible sections in the air andgas supply duets - Adjacent the inlet end of the furnace casing is a
billet feed mechanism 47 for orienting and feeding a regular supply of billets onto theinlet section 34 of theskid 31. In the present example thebillet fee mechanism 47 is of a known type comprising a pair of vibrating bowls (not shown) from which oriented billets are supplied via lateral feed paths 48 to a pair of feed positions on opposite sides f a stop 49 which is aligned with the axis of theskid 31. Associated with the two feed positions are a pair of pushers 50 arranged to be advanced and retracted bypneumatic cylinders 51, and by operating the cylinders out of phase billets are pushed alternately from the two feed positions through a tapering guide 52 to an outlet path 53 leading onto theinlet section 34 of the skid. In operation thecylinders 51 of thefeed mechanism 47 are actuated in response to a signal from the press which is being fed by the furnace, so that each time a billet is stamped by the press one of the pushers 50 is advanced to push a fresh billet towards the skid, thereby advancing all of the billets already on the skid and causing the leading billet to be fed to the press for the next stamping stroke. - Mounted-on the
support 9 adjacent the outlet end of the furnace casing is abillet discharge mechanism 54 having aguide channel 55 arranged to receive billets from the outlet end of theskid 31 and leading to avertical passage 56 through which the billets are arranged to drop and which forms the lead-in part of adelivery chute 57 leading to the press. For the purpose of detecting any interruption in the regular supply of billets to the press during normal operation, thedischarge mechanism 54 is provided with abillet sensor 58 in the form of a lever which is pivotally mounted about anaxis 59 and which has a rest position, determined by astop 60 engaging the lever, t in which onearm 61 of the lever projects laterally into thepassage 56 and theother arm 62 of the lever blocks apneumatic passage 63. When a billet drops down thepassage 56 to thedelivery chute 57 it engages thearm 61 of thesensor 58, causing the sensor to pivot about theaxis 59 so that thearm 62 unblocks thepassage 63 to allow a pulse of air to flow to a timer (not shown) until thepassage 63 is again closed when thesensor 58 returns to its rest position. The pulse sets the timer in operation, the timer being arranged to time out and issue a shut down signal if a predetermined time elapses without another billet dropping down thepassage 56. The predetermined time is set to be greater than the normal interval between successive billets in the regular supply to the press. Consequently, during normal operation, the timer will not have timed out when the next billet drops down thepassage 56 and pivots thesensor 58 to cause a fresh pulse to be sent to the timer, which is thereupon restarted. However, if for any reason there is an interruption in the regular flow of billets down thepassage 56 the timer will time out and initiate a stop signal in response to which a control valve (not shown) in thegas supply duct 37 is closed to shut down the burners. - Also incorporated in the
billet discharge mechanism 54 is a reject facility. This comprises aslide 64 which forms part of the floor of thechannel 55 and which can be moved laterally to uncover a secondvertical passage 65 in the path between the discharge end of theskid 31 and thepassage 56 leading to thedelivery chute 57. The secondvertical passage 65 leads to areject chute 66 and, when open, prevents any billets from reaching the delivery passage andchute slide 64 is moved between its open and closed positions by means of apneumatic cylinder 67 which is mounted on the side of thelower casing part 1 and which has itspiston rod 68 connected to theslide 64 through a series of pivotally connectedlinks cylinder 67 is arranged to be operated to open theslide 64 automatically at the same time as the burners are shut down, and there is also means (not shown) for manually actuating thereject cylinder 67. ` In either case, however, the slide can be closed only by manual actuation of a switch (not shown) so that, on start-up or after any stoppage, billets will not be supplied to the press from the furnace until the operator decides to close theslide 64, that is when he is satisfied that the billets are being heated to the required temperature. - The controls of the furnace are arranged so that, during operation, the gas control valve will close to shut down the burners in response to any one of the following happenings, detection of billet flow failure by the
sensor 58, low pressure in either of the air andgas supply ducts furnace chamber lid 2 as detected by aswitch 20 and actuation of a stop push button by the operator. In addition to closing the gas control"valve, occurrence of any one of the above will also cause the controller to drive the modulating air valve to the minimum setting, deactivate thebillet feed mechanism 47 to stop the supply of billets, and operate the reject mechanism to open thegate 64 to thereject chute 66. It is to be noted that the burners cannot be ignited if thefurnace lid switch 20 is open or if either of the low pressure sensors in the air and gas supply ducts signal that the pressure in the duct is too low.
Claims (18)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB08121076A GB2101281B (en) | 1981-07-08 | 1981-07-08 | Billet heating furnace |
GB8121076 | 1981-07-08 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0070115A2 true EP0070115A2 (en) | 1983-01-19 |
EP0070115A3 EP0070115A3 (en) | 1984-06-13 |
EP0070115B1 EP0070115B1 (en) | 1987-01-07 |
Family
ID=10523096
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19820303345 Expired EP0070115B1 (en) | 1981-07-08 | 1982-06-25 | Billet heating furnace |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0070115B1 (en) |
JP (1) | JPS6050850B2 (en) |
DE (1) | DE3275004D1 (en) |
GB (1) | GB2101281B (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61179954U (en) * | 1985-04-26 | 1986-11-10 | ||
RU2586382C1 (en) * | 2015-02-02 | 2016-06-10 | Открытое акционерное общество "Всероссийский институт легких сплавов" (ОАО "ВИЛС") | Device for controlling heating of workpieces in pusher-type induction heating furnace |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2244532A1 (en) * | 1972-09-11 | 1974-03-21 | Riedhammer Ludwig Fa | DEVICE FOR MONITORING THE FEED OF TUNNEL FURNACES WITH PLATE CONVEYOR |
DE2802721A1 (en) * | 1978-01-23 | 1979-07-26 | Junker Gmbh O | Pusher type furnace - with sectional extraction device between carrier rails |
-
1981
- 1981-07-08 GB GB08121076A patent/GB2101281B/en not_active Expired
-
1982
- 1982-06-25 EP EP19820303345 patent/EP0070115B1/en not_active Expired
- 1982-06-25 DE DE8282303345T patent/DE3275004D1/en not_active Expired
- 1982-07-07 JP JP11830882A patent/JPS6050850B2/en not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2244532A1 (en) * | 1972-09-11 | 1974-03-21 | Riedhammer Ludwig Fa | DEVICE FOR MONITORING THE FEED OF TUNNEL FURNACES WITH PLATE CONVEYOR |
DE2802721A1 (en) * | 1978-01-23 | 1979-07-26 | Junker Gmbh O | Pusher type furnace - with sectional extraction device between carrier rails |
Non-Patent Citations (1)
Title |
---|
ZEITSCHRIFT F]R METALLKUNDE, vol. 62, no. 1, January 1971, pages 21-26 * |
Also Published As
Publication number | Publication date |
---|---|
JPS6050850B2 (en) | 1985-11-11 |
GB2101281B (en) | 1984-10-10 |
JPS58123827A (en) | 1983-07-23 |
EP0070115A3 (en) | 1984-06-13 |
EP0070115B1 (en) | 1987-01-07 |
GB2101281A (en) | 1983-01-12 |
DE3275004D1 (en) | 1987-02-12 |
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