WO1995016795A9

WO1995016795A9 - Furnace spraying repair device

Info

Publication number: WO1995016795A9
Application number: PCT/US1994/014333
Authority: WO
Filing date: 1994-12-12
Publication date: 1995-07-20

Abstract

The invention comprises hoppers (28) containing spray material, spray machines (30) at the bottom of the hoppers (28), a hose (36) conveying the material from the spray machines (30) to an automatic spraying machine (34) inside a furnace (32), and an air conveying means (38) for supplying material from the hoppers (28) via hose (36) to the automatic spraying machine (34).

Description

FURNACE SPRAYING REPAIR DEVICE The present invention relates to a device for repairing the lining covering the inside of a furnace shaft which has been melt damaged by heat, by spraying a spray material, and in particular relates to a multi-tank spraying repair device intended to repair the necessary places rapidly by automatically and continuously expelling a large amount of spray material. Prior Art

With the gradual increase in the capacity of furnaces which has occurred recently, large-scale furnaces of between 4000 and 5000 cubic meters are currently in operation. Further, their life has also gradually extended, due to improvements in the actual fire resistant materials which are used in the furnace, for example. However, damage naturally occurs to furnaces when they are used, and in particular melt damage to the shaft is serious. Thus in order to further extend the life of the furnace and to perform efficient operation, it is necessary to repair the melt damaged portions of said shaft by means of a spraying means, for example.

Various types of furnace repair device have been presented in reply to this need. However, the most widely used method is that shown in Figure 3. This furnace spraying repair device 1 consists of a hopper 3 which receives spray material with which bags 2, which are transported by means of a fork lift or the like, are filled, a pre-dampener 6 which mixes in primary added water to the spray material by means of a spray means 5 whilst is fed said spray material from said hopper 3 by means of a feeder 4, a spray machine 7 which receives the spray material which has been pre-adjusted by means of said pre-dampener 6, and an air conveying means 11 for pneumatically conveying the spray material which is accommodated within said spray machine 7 to a furnace automatic spraying machine 10 which is located inside the furnace 9, using a material hose 8 or the like. Spray machines which are widely used as the spray machine 7 used in this example include: as shown in Figure 4 (A) for example, a torque let double construction chamber type spray machine in which two chambers, an upper chamber and a lower chamber, are each connected such that they can be opened and closed, by means of unidirectional valves, and in which material is supplied from the lower chamber; as shown in Figure 4 (B) for example, a rotor type spray machine in which a rotor which has a plurality of passages which pass through in the vertical direction is rotated around a vertical axis whilst supplying material; and as shown in Figure 4 (C) for example, a blade gun type spray machine with an attached rotary feeder in which a rotary which has a pair of channels extending in the horizontal direction rotates around a horizontal axis whilst supplying material. In such a repair device 1, when spray material in the form of cement powder passes through the pre-dampener 6, it is continuously supplied to the spray machine 7 in a state in which primary added water has been added, and the spray material which has been supplied in this way passes through the valve, rotor or rotary, for example, in the spray machine 7, and is then sent from the spray machine 7 via the material hose 8 to the furnace automatic spray machine 10 which is located in the furnace 9, by means of a high pressure means 11 which comprises, for example, an air compressing means such as an air compressor, and a compressed air conveying means such as an air hose which conveys compressed air generated by means of the air compressing means, and then after a prescribed amount of water has been mixed into the material, said material is sprayed onto the melt damaged portions of the shaft of the furnace 9 from the nozzle of the furnace automatic spray machine 10, thereby effecting the prescribed repair. Such repair work is performed continuously from the start of spraying after the spray material has been input into the hopper 3, until spraying is complete, and the work is performed by remote control whilst an operative at the top of the shaft of the furnace 9 looks inside the furnace 9 through an opening 12. In such a known spray repairing device 1, the places to be repaired and the state of the melt damage are estimated in advance, and the repair work is performed whilst the hopper 3 is continuously filled with the amount of repair material required to effect the repairs. Problems to be Overcome by the Invention

However, the operation of the furnace must be stopped in order to perform this spray repair work, and therefore it is desirable, from considerations of the operating efficiency of the furnace, for the spray repair work to be completed in as short a time as possible. In spite of this, the repair material expelling capability of furnace spraying repair devices 1 in the past has been of the order of 5 to 7 tons per hour, and this capability is extremely small for a device which is intended to repair, in particular, the recent large scale furnace, and thus the spray repair time is extended and therefore the downtime of the furnace is correspondingly extended. There has thus been the desire for a furnace spraying repair device to be developed having the capability to expel an amount of spray of the order of 10 to 20 tons or more per hour.

Furthermore, with the furnace spraying repair devices in the past, primary added water is mixed into the repair material which is in the form of cement powder, by means of a spray means 5, in the pre-dampener 6. Thus the repair material begins to set from this moment. It is therefore desirable to supply the repair material to which the primary added water has been mixed as rapidly as possible to the maintenance areas of the furnace. However, valves, rotors, and rotaries, for example, as described above, are provided in the spray machine 7 in order to guarantee a uniform supply of repair material. However, the torque let double construction chamber type device has the disadvantage that, since it has a double chamber which is opened by the action of a valve, it is suitable for small amounts of expulsion but does not lend itself to large amounts of expulsion, and further the operation during opening and closing of the valve, for example, requires skill. Furthermore, the rotor type and rotary type devices have the disadvantage that it is necessary to replace rubber seal materials which are provided around said rotor and rotary, since during the spraying operation they are liable to wear, and it is necessary to interrupt the operation frequently, there are many expendable items, and the running costs are extremely high. Further, the maximum amount of spray expulsion is no more than about 7 tons per hour in practice, and this is far from reaching the required rate of 10 to 20 tons per hour. Furthermore, operation of the spray machine also requires a high degree of skill in controlling the expulsion pressure and expulsion quantity. Furthermore, in devices in the past, the pre-dampener 6 which mixes primary added water to the repair material when said repair material is input into the spray machine, is indispensable in order to prevent the occurrence of dust in the spray machine 7 and to aim to increase the expelled amount of material, and thus said repair material often becomes attached inside the device and sets during operation, and the situation often arises that the repair operation must be interrupted in order to carry out cleaning. Thus in repair devices 1 in the past, it has always been necessary to prepare two pre-dampeners 6 and spray machines 7, and an operating procedure is required in which whilst one is being used the other is being cleaned. However, such a procedure is not preferable in terms of space or cost-effectiveness. Furthermore, in devices in the past, the spray material powder which is used as the repair material is conveyed and fills the hopper 3 in an open cycle. Thus a large amount of dust is generated in the vicinity, the working environment is degraded markedly and there is an extremely serious problem in terms of the health of the operatives in particular when working continuously for a long time. Summary of the Invention

In order to overcome the above- mentioned various problems, the present invention is arranged such that a plurality of spray machines are provided linked together, and a large amount of repair material can be continuously supplied. Furthermore, the transportation cycle of the material is a completely closed cycle and thus pollution of the working environment is prevented to the utmost. Furthermore, the pre-dampener does not need to be used, the mixing process with primary added water is eliminated, and clogging of the device due to the setting of material, and the necessity to replace components are minimized. Furthermore, all of the operation of the whole device is incorporated in a prescribed program, and the operations which need to be performed by operatives are extremely simple.

As a result, the present invention has the capability to expel a large amount of repair material to complete the repairs to large scale furnaces in a short time. Further, since the spray material powder is only transported in a closed cycle, the surrounding environment is not polluted by dust from said material powder, or the like. Furthermore, since the pre-dampener is not needed, there is no danger that the material will set before reaching the inside of the furnace, and the amount thereof, the transfer rate and the output pressure, for example, can be rigorously controlled with certainty, whilst problems such as clogging of the device and wear of components can be completely eliminated. Furthermore, since the operating procedure is completely programmed, it is possible for the operation performed by the operatives to be greatly simplified. Brief Description of the Drawings Figure 1 An explanatory diagram showing the whole of the present invention. Figure 2 An enlargement of part of the present invention. Figure 3 An explanatory diagram of the whole of a known device.

Figure 4 A diagram showing the inside of the spray machine of a known device. Explanation of the References

20 furnace spraying 22: I beam repair device

24: hoist 26: bag

28: hopper 30: spray machine

32: furnace 34: automatic spray machine

36: hose 38: air conveying means

40: cutter 42: valve

44: spray machine 45: exhaust valve main body

46: load cell 48: control panel

50: valve 52: Y-shaped tube

54: valve 56: valve

58: feeder Embodiment

As shown in Figure 1, the furnace spraying repair device 20 according to the present invention consists of a plurality (only 2 are shown in Figure 1) of spray material input hoppers 28 which receive spray material in powdered form, with which bags 26, which are transported by means of an electric hoist 24 to which trolleys are attached via a hoist I beam or the like 22, are filled, a spray machine 30 which is provided at the bottom of said hopper 28, a material hose 36 which sends the supply material from said spray machine 30 to an automatic spray machine 34 inside the furnace 32, in the powdered state, and an air conveying means 38 for supplying the material from the above-mentioned hopper 28 via the hose 36, in the powdered state.

The embodiment of the furnace spraying repair device 20 which is shown in the diagrams comprises 2 hoppers 28 and spray machines 30, but it will be clear to one skilled in the art that they are not limited to 2 units.

The construction and operation of the device of the present invention will now be described. It is desirable for the capacity of each spray machine 30 to be at least 2 tons of furnace material. The spray material is input into the hoppers 28 by means of the hoist 24. At this time, the bags 26 which are flexible containers accommodating the spray material are desirably automatically opened by means of a flexible container cutter 40 which is accommodated inside the hopper 28, as shown in Figure 2. A spray machine main body, in other words a furnace material tank 44, which has at its neck a butterfly valve 42 with an attached actuator which adjust the supply of material, and, at its shoulder, an automatic exhaust valve 45 with an attached actuator, which is connected to the inside, is provided at the bottom of the hopper 28. Thus the spray material with which the hopper 28 is filled drops down into the furnace material tank 44 by opening the exhaust valve 45 and opening said butterfly valve 42 which has an attached actuator. After this input, said butterfly valve 42 which has an attached actuator, and the above-mentioned automatic exhaust valve 45 which has an attached actuator for discharging air from said tank 44 are closed. This completes the preparation operations. It is preferable for the preparation operations to be performed simultaneously for all of the spray machines 30. The amount of spray material received into each tank 44 at this time is continuously displayed on an automatic control panel 48 by means of load cells 46.

The spray start button on the control panel 48 is then switched on. Thus one of the ball valves 50 which have attached actuators and which are provided at the bottom of the spray machines 30 is first opened, and compressed air for pressure conveying the spray material, which compressed air is supplied in a stabilized state via a known air receiver tank from the compressor, or the like, of the air conveying means 38, flows via the bottom of the tank 44. At the same time, the ball valve 54 which has an attached actuator, on one spray machine side of a flow-dividing Y-shaped tube 52 is opened, and the ball valve 56 which has an attached actuator, on the other spray machine side is closed. A variable dose feeder 58 which is attached with freedom to rotate inside the above-mentioned one spray machine 30 begins to rotate, and the spray material inside the tank 44 is conveyed to the furnace automatic spray machine 34 through the material hose 36 by means of compressed air. It should be noted that the operation of these valves etc. is driven automatically by means of electromagnetic valve operation by means of compressed air from an air compressor, or the like, which is operated by means of an automatically controlled programmed procedure.

Material which passes through the material hose 36 and a known opening in the furnace 32, and is supplied to an automatic spray machine 34 inside the furnace, which is supported by means of a similarly known furnace automatic spray machine raising/lowering electric hoist and a suspension chain, for example, is then mixed with a prescribed amount of added water, is sprayed onto the melt-damaged portions of the furnace, via a nozzle, thereby effecting the desired spray repairing.

When the material supply from one spray machine 30 has been used up, in other words when the load cell display is zero, then the ball valves 50 and 54 of one spray machine 30 are closed by means of an instruction from the control panel 48, and furthermore the supply of compressed air stops and the feeder 58 stops.

The valve 50 of the other spray machine 30 which is provided adjacently, and the valve 56 of the Y-shaped tube are opened, compressed air for conveying flows into said spray machine, and the feeder of said spray machine begins to rotate, and the same material supply operation continues without interruption. However, input of material into the emptied spray machine 30 can be performed by means of the following procedure. To elaborate, firstly the exhaust valve 45 which has an attached actuator is opened, and air remaining within the tank 44 of said spray machine 30 is dispelled to the atmosphere. The valve 42 which has an attached actuator is then opened, and material with which the hopper 28 has been filled in advance is supplied into the tank 44.

Then when the supply of material from the other spray machine 30 has finished, supply of material from the one spray machine 30 begins in a continuous manner, by the same means. Thus continuous supply of material is achieved. When repair inside the furnace is complete, the whole operation is completed by pressing an automatic stop button on the continuous automatic control panel 48. In the device 20 according to the present invention, the inside of the spray machine 30 is connected to the atmosphere by means of the exhaust valve 45, in order to achieve simple filling of material from the hopper 28, but it is also possible for said exhaust valve 45 to be connected to a negative pressure source and for said tank 44 to be put in a negative pressure state only when this is required. Furthermore, it is possible to supply high pressure air from said valve 45 when material is supplied from the tank 44 in order to plan to regulate the supply of material. Furthermore, in the present invention, the diameter of the butterfly valve 42 which has an attached actuator is approximately 50% larger than the diameter in conventional spray machines, and thus material in the hopper 28 can be input into the spray machine main body 44 in a short time; the blade pitch of the material supply feeder 58 is approximately twice that of the pitch of conventional spraying machines, and thus it is possible to expel a large amount of spray material continuously; furthermore, the diameter of the exhaust valve 45 is approximately twice that in conventional spray machines, and thus it is possible to expel air remaining inside the spray machine main body 44 after spraying, rapidly to the atmosphere; furthermore, the material on the inside surfaces of the ball valves 50, 54 and 56 which have attached actuators has been changed to a material which has good anti-abrasion properties, and thus high quantity expulsion can be performed continuously for a long time; a flexible container cutter 40 is provided inside the hopper 28, and thus flexible container bags 26 which have been input into the hopper 28 can be automatically and rapidly opened; and spraying operations can be performed continuously by using a plurality of batch type spray machines, by means of an automatic continuous control program, and thus the spray machines 30 in the present invention are arranged such that a large amount of spray material can be sprayed continuously. Furthermore, in order that the spray machines 30 can be transported by means of a truck, or the like, the diameter of the spray machine main body 44 in the present invention is approximately 30% larger than that in conventional spray machines, but the height is reduced, and thus by maintaining capacity and making the hoppers 28 such that they can be removed, they are within the height limits for highways, and can thus be transported easily at any time.

The advantages of the spray repairing device according to the present invention are as follows.

With known devices it was not possible to spray a large amount of spray repair material continuously, and the spray repair operation required a large amount of time, but in the present invention it is possible to supply material continuously by making use of a plurality of spray machines 30, and it is possible to shorten the spray repair operation. Indicating this numerically, the actual amount of material which is expelled in a known device is from 5 tons per hour to a maximum of only 10 tons. However the device of the present invention allows variable dose expulsion amounts of between 5 tons per hour and a maximum of 20 tons.

Further, the spray repair material is normally a powdered fire resistant material. However, in conventional devices primary added water is mixed into said spray repair material when it is supplied from the hopper 3 to the spray machine 7, and this is all performed in an open cycle, resulting in unmixed material causing dust at all times. However, in the device of the present invention, supply of material from the hopper 28 to the spray machine

30 is performed in a completely closed cycle, and there is thus absolutely no danger of the working environment being polluted.

Further, in known devices, in order to prevent environmental pollution and degradation of the working environment due to dispersion or leaking of the powdered fire resistant material dust, and to plan to increase the amount of expulsion, primary added water is mixed into the material at the stage at which the material is supplied to the spray machine 7, and thus situations occur in which said material sets inside the pre-dampener 6 and the spray machine 7, causing clogging of the rotors and the like in the spraying machine 7, and moreover readily causing the rubber seals and the like to wear. Thus in order to remove the set material which is adhered to the pre-dampener 6 and the spray machine 7, and in order to clean the clogged rotors and the like, and in order to exchange worn rubber seals, it is necessary to interrupt the operation frequently, and this inevitably leads to delays in operation, but in the present invention primary added water is not mixed in and therefore these problems are not present.

Further, in known devices, in order to prevent the generation of dust, a large number of seal components are used inside the devise, and further a large number of expendable components and components which wear are used as the seal portions inside the spray machine 7, in particular, in order to feed the gelled material into which the primary added water has been mixed, and thus the running costs are extremely high, but in the present invention the operation is performed in a closed cycle, and thus these problems are completely solved.

Furthermore, in known devices, an operative must always monitor the state of the primary added water supply in the pre-dampener 6, and must determine the state of mixing between the material and the added water, and furthermore the pressure and_. quantity, for example, of the mixed material in the spray machine 7 must constantly be monitored, and the optimum amount of material must be expelled in the optimum state from the nozzle of the furnace automatic spray machine 10. Furthermore, this work requires skill obtained over many years.

Thus conventional spray repairing operations can only be performed by particular individuals. However, in the device of the present invention, all of the operations can be run by means of an automatic control operation using a preset program, and thus there is no need for any particular skill. Thus the device of the present invention can be obtained much less expensively than known devices.

Claims

C L A I M S 1. A furnace spraying repair device which rapidly repairs the necessary places by automatically and continuously expelling spray material, wherein said furnace spraying repair device is intended to repair the lining which covers the inside of the shaft of a furnace which has been melt damaged, by spraying a spray material, which furnace spraying repair device comprises a plurality of spray material input hoppers 28 which receive powdered spray material, spray machines 30 located at the bottom of said hoppers 28, a material hose 36 which supplies the spray material from said spray machines 30 to an automatic spraying machine 34 inside a furnace 32, in the powdered state, and an air conveying means 38 for supplying material from the above-mentioned hoppers 28 via the hose 36 in the powdered state, wherein the above-mentioned spray machines 30 comprise a spray machine main body 44 which accommodates the spray material from the above- mentioned hopper 28, and a load cell 46 for indicating the amount of material accommodated within said spray machine main body 44, and further said spray machine main body 44 is provided with a valve 42 which controls connection with the hopper 28, an exhaust valve 45 which connects the inside of said main body to the atmosphere, a valve 50 which controls the flow of spray material from said main body 44, and a material supply feeder 58, and the air conveying means 38 leads from a high pressure generating source to the spraying machines 30, and then from said spraying machines 30 to a connector 52 to which an automatically opening and closing valve is attached, and the air conveying means 38 is subsequently connected to the automatic spraying machine 34 inside the furnace. 2. The furnace spraying repair device as claimed in claim 1, wherein the opening and closing of the opening and closing valves: valve 42, exhaust valve 45, valve 50, and connector 52, are automatically controlled by means of high pressure air. 3. The furnace spraying repair device as claimed in claim 1 or claim 2, wherein two spraying machines 30 are provided, and the connector is a Y-shaped pipe. 4. The furnace spraying repair device as claimed in claim 3, wherein if the signal from a load cell 46 indicates that the material within one of the spraying machines 30 has been used up, then supply of material from the other spraying machine automatically commences.