DE2001006A1 - Bell furnace - Google Patents

Description

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6160 BETHLEHEM STEEL CORPORATION, Bethlehem, Pennsylvania, V.St .A,

Bell furnace

You invention relates to a bell furnace with a Ba8isteil and a removable cover on this, which with the The base part forms a heating chamber in which a gaseous atmosphere is circulated. The invention also relates to bell ovens for tempering and / or chrome-plating metal products, in particular an improved base part and an inner cover or hood for such an oven.

Bell furnaces generally have a base part on which the metal, usually in the form of a coil or helix, is stacked, a removable inner cover which rests on the base part and forms a heating chamber with it, and a refractory-lined outer cover, which is arranged over the inner cover. Heating units in the outer cover generate the heat for the chamber. A gaseous atmosphere is fed through pipes to the heating chamber, in which it is circulated by means of a fan attached to the base part. A Entweiohen the gaseous atmosphere from the heating chamber and "ine infiltration of air into the chamber to prevent eieht one means ₁ the zwieohen the base portion and the inside seal cover. Which is introduced during a tempering «ykluiin dl · heating chamber · ,, gaseous · atmosphere

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non-reactive, while the gaseous atmosphere supplied in the course of at least part of a piping cycle is reactive and contains CMor. The chlorine containing, A reactive, gaseous atmosphere is corrosive, and in order to prevent its infiltration into the furnace base part, the furnace base part is provided with a gas-tight jacket, which is a Forms chamber and surrounds a porous shaped, refractory base. The elements of the jacket are connected to one another and sealed by welding to protect against this infiltration. To provide further security against one To obtain possible penetration of the reactive gaseous atmosphere into the base shell becomes a non-reactive, sealing gas under a higher pressure than that of the reactive gaseous atmosphere in the hot chamber is introduced into the jacketing chamber, thereby pressurizing it.

The usual construction of a bell furnace base part has a Base plate, a refractory base and a top plate, all of which are ring-shaped. External and internal perimeter side panels They extend between the bottom plate and the top plate and form a chamber which is filled by the refractory Sookel. Across the opening in the base plate and on If this is screwed on, the fan that circulates the gaseous atmosphere in the Helekammer extends through. A trough runs around the outer circumference of the base part and serves to accommodate a Diohtungsmitttls as well as to accommodate the lower The end of the inner disintegration, which descends near the bottom in the dietetic agent. A series of lines including the Inlet and outlet pipes for the gaseous atmosphere, aowie Thermocouple cables eratreoken iloh duroh daa Baalatail and and attached to the upper and lower plates

The temperature inside the inner cover tinea Olookenofena reaches during a · Vergtttungaiyklua 643 ° bit 753 ⁰ O (1200 bit

UOO ⁰ F) ₉ and during a ·· Varohromungaiyklua the tenpe-

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temperature up to about 945 ⁰ C (175 ⁰ P). Alternating heating and cooling of the furnace cause the base top plate to expand and contract considerably. This expansion and contraction of the top plate requires that the inlet and outlet tubes for the gaseous atmosphere, as well as the thermocouple lines, be provided with liquid metal seals which allow these parts to change their position to a limited extent. In addition, portions of the base are made from a metal such as Incone1 (TM), which has high strength at elevated temperatures. In spite of various devices that have been used to compensate for the expansion and contraction of the base part elements during operation of the furnace, a break in the welds occurs relatively often: which connect the pipes and lines to the base part. The weld seams that unite the elements of the base part are also often broken. In addition, the upper base plates sometimes crack or split in a generally radial shape. Failures of this type result in high maintenance and replacement costs and require the furnace to be taken out of service for extended periods of time while the base part is being repaired. In addition, the tubing and conduits which extend through the base into the area below it easily clog that area and create difficulties in servicing other furnace components.

The invention is therefore based on the object of creating a bell oven which is simpler in construction and less expensive to maintain than the ovens currently in use. It is also intended to provide an improved bell furnace base which has inlet and outlet pipes for the gaseous atmosphere that pass through the Baeia top plate.

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Finally, a GIockenofen basic casing is to be created which is gas-tight and has an upper plate which is not rigidly connected to the other sheathing elements, so that it can expand and contract with relative freedom.

To achieve this object, a bell furnace of the type described at the outset is characterized according to the invention by a trough running in the circumferential direction which extends around the base part, a device which extends into the trough in order to introduce the gaseous atmosphere into the heating chamber Device that extends out of the trough to discharge the gaseous atmosphere from the heating chamber, a removable hood-side wall construction, the lower end of which extends neon below into the base circumferential trough and by means in the trough between the lower end of the remote , baren hood-side wall construction and the trough create a seal and prevent the escape of the gaseous atmosphere from the heating chamber.

The bell furnace according to the invention accordingly has a base part in which the inlet and outlet pipes for the gaseous atmosphere extend through the base sealing trough on the outer circumference. The fireproof base is enclosed by a gas-tight casing. The casing contains outer and inner circumferential troughs adjacent the upper ends of the outer and inner side walls of the casing, as well as means that seal between the outer side wall and the outer trough and the inner side wall and the inner trough Uafangaflanaohe, which protrude downward in the outer and inner Umnantavlungemulden, welohe means comprise, dta zwlaοhen represents Oberplattanflanaohen and dan wells haratellen a seal.

The invention will now be explained in detail with reference to the accompanying drawings described, with all details or features emerging from the description and the figures for the solution can contribute to the task within the meaning of the invention and with the ■ Willing to be patented in the application. Show it:

fig. 1 is a vertical sectional view through part of a Bell furnace according to the invention.

Pig. Figure 2 is an enlarged top sectional view taken along line 2-2 of Pig. 1, which shows the lower end of the removable inner cover or hood "also the outer circumferential trough of the base" and the ^; Gas inlet pipe of the Pig's furnace. 1.

Pig 3 is a cross-sectional view taken along line 3-3 of FIG Pig. 2.

Fig x 4 is an enlarged detailed view of a portion of the oven of the e Of Pig. 1, which shows a type of seal between the side wall of a base demolition, the waterproofing trough and the top plate provided with a plano

71g x 5 is an enlarged detailed view of a portion of the Pig's furnace. 1, which creates a different kind of insulation between a side wall of the casing, the indentation and the upper plate.

Description of the preferred embodiment

Reference is now made to the reference in Pig. 1 1st "in T" ll "inea Ölookenofene 10 shown, which has" in Baala part 11 and "in" removable, inner "cover or hood" 12, dl "with a "Heizkammtr 13" forms the component part. The component part a'it alob together from a load-bearing O'at'll H, tiner outer

Circumferential trough 15 _t an annular refractory base 16, a jacket 17 which forms the chamber 60 and encloses the base, and a core section 18. The core section is provided with a central, vertically extending sleeve 19 and has an annular cooling chamber 20, which the Clasps around the sleeve, as well as an annular refractory part 21. On the base part 11 a diffusion chamber 22 is fixed, which is overlaid by a filling chamber 23 which carries metal coils or turns to be treated in the heating chamber 13; A fan device 24 is attached to the bottom of the base part, the shaft 25 of which extends upward through the core sleeve 19 and carries a propeller 26 at its upper end.

As FIG. 3 shows, the outer circumferential trough 15 of the base part contains a bottom plate 27, an outer side wall 28 and an inner side wall 29 which extend close to the top against the bottom of the base casing 17. The trough 15 let partially filled to a depth d with a suitable waterproofing material 30, which can consist of sand or wood metal, for example. Inlet and outlet pipes 31 and 32 for the gaseous atmosphere extend upward through the trough bottom plate 27 on opposite sides of the furnace. The pipes 31 and 32 are described hereinbelow for the sake of the Muldenaeitenwänden 28 and spaced 29, and eratreoken over the trough bottom plate 27 by a distance e, is greater than the depth d of the Abdiohtungamaterlale 30 in the well 15 lat.

The removable hood 12 protrudes with its lower end 33 into the Abdiohtungamitttl 30 in the trough 15 into it. At a distance from the lower end · 33 of the inner hood and the opposite one There are seldom gas inlet and outlet openings in the hood 34 biw. 351 with the inlet and outlet pipes 31 and 32 for the gaseous atmosphere in the trough 15 lusamaenvirkeiu <* ·· - • INLET AND EXHAUST HOUSING 36 dsw · 36 '»dl · each one open Have bottom, eratreoken sloh rom lower end 3? the inner hood near the outside and around the bottom, including the openings 34

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and 35. Each housing has a top plate 37, side plates 38 and an outer plate 39 extending from the inner Hood 12 is arranged at a distance L which is greater than the outer diameter D of the inlet and outlet tubes 31 and 32, respectively is. Extends from the lower end 33 of the inner hood and around the bottom of the grass inlet opening 34 of the inner hood Inward and upward channel 40 which runs along the inner side of the inner hood to a point over the base part 11 · «· The channel 40 has an open top end 41 and has side walls 42 and an inner wall 43.

As by the arrows in Pig. 1 and 2 is indicated, the gaseous atmosphere migrates from a source not shown through the inlet tube 31, the inlet housing 36, the gas inlet port 34 of the inner hood and the channel 40 into the heating chamber 13. The gaseous atmosphere is in the heating chamber 13 by means of the fan propeller 26 circulates and migrates out of the heating chamber out through the outlet opening 35 of the inner hood, the Outlet housing 36 * and outlet pipe 32.

The base casing 17 is made gas-tight for reasons explained below. As shown in Figure 1, the base shell 17 including the refractory base 16 includes an annular bottom plate 44, an outer side plate 45 extending upwardly near the outer periphery of the bottom plate, an inner side plate 46 extending near the inner periphery of the Bottom plate extends upwardly and a top plate 47 which has outer and inner peripheral flanges 48 and 49, respectively, extending near the bottom. The outer and inner side panels 45 and 46 are attached to the bottom panel 44 by welding the parts together to form gas-tight joints. In the refractory base 16 are near its upper outer. and inner circumference semicircular casing troughs 50 and 51, respectively, partially embedded. The hollows 50 and 51 contain a hatred of a seal amat er la Is 52, such as lead, which is used in the

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Oven working temperatures becomes liquid. The outer splash 48 the upper plate extends down into the sealing material 52 in the outer trough 50, and the inner flange 49 of the upper Plate extends down into the sealing material 52 in the inner trough 51 of the casing, creating a gas-tight Connection between the top plate 47 and the troughs 50 and 51 is established. Like in Pig. 4 is shown in detail the outer side plate 45 of the casing with the outer trough 50 of the casing through the weld seam ι. 53 connected that makes this connection gas-tight. Instead of a weld seam to seal a trough and a side plate, Pig. 5 in Detail shows a modified form of construction. The inner side panel 46 of the shell is here adjacent to its upper one End provided with a plan 54 which extends from the jacket inward and downward into the sealing material 52 in the inner trough 51 extends into it, creating a gas-tight seal between the side plate 46 and the inner trough 51 is created. The gas inlet tube 55 and outlet tube 56 of the jacket extend on opposite sides of the Casing through the bottom plate 44 into the casing chamber 60 and through the refractory base 16 into the channel 57 in the top of the base 16 next to the Underside of the top plate 47 runs in a circle. An unreactive sealing gas, such as hydrogen, is over the jacket gas inlet pipe 55 is introduced into the passage 57 of the jacket chamber 60 at a pressure higher than that the reactive gaseous atmosphere that is circulated in the heating chamber 13. This sealing gas flows through the channel 57 in the top of the base 16, the casing chamber 60 is pressurized and is from this via the Drained pipe 56. Hence, should there be any defect in the parts, connections or seals of the base shell 17 the non-reactive sealing gas escapes from the jacketing chamber. As a result of the higher pressure of the sealing Gaeee does not find any infiltration of the reactive gaseous Atmosphere from the heating chamber into the jacket

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or through them into the area below the base part.

The various features of the bell-shaped oven described above, in combination, result in an oven which is in many respects superior to those currently in use. The arrangement of the inlet and Auslaßr-ray tube for the gaseous atmosphere in the base peripheral trough 15 and the modification of the inner cap for receiving these tubes is a significant improvement. & I ese pipes are now located at a position which is considerably cooler than one near the top plate of the jacket so that they are no longer subject to the considerable expansion and contraction which earlier led to their failure. It will be recognized that other tubes and lines, such as those used for thermocouples, can also be inserted into the furnace through the base perimeter trough 15 so that these tubes and lines can be neatly spaced around the base perimeter and not clog the area below the base shell. An existing base can be easily modified to locate the grass inlet and outlet connections in the base perimeter trough, and a removable inner hood can be modified to accommodate the gas inlet and outlet ports 34 and 35 and their respective housings. A new inner hood can be made with a diameter that is sufficiently large that its lower end extends into the base circumferential recess or into the space between the outer side wall 28 of the recess ur.-l άβζί öaseinlaß- and outlet pipes 31 and 32 «If the construction 17 is carried out so that it contains an upper plate 47 with jafangeflaneohen 48 and 49, which are placed in neon at the bottom in the sealing material 52 in the troughs 50 and 51, can be vie cfcare plates during an oven work cycle u & hindered- β us de hen xwiä ^ ueammenzug. By men the welds .tv, --- 1 fs M ff η can * in current Glüokenttfm O '^ rplatt © i' r Basie "sheath and Seitöi zrisctjen; pli * tt # n voraendey: η i.-. -v " _f vl-tf ds?> Who-

problem of this connection switched off. If a replacement When the top plate of the jacket becomes necessary, a new plate can be installed with a minimum of time and effort will. This in itself is a significant improvement, given the time and effort involved, as well compares the cost of materials involved in restoring There are basic changes in existing ovens.

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Claims (1)

Claims 1. Bell furnace with a base and a removable cover on this, which forms a heating chamber with the base part in which a gaseous atmosphere is circulated, characterized by a trough (15) running in the circumferential direction, which extends around the base part (11) extends, a device (31) which extends into the Trough (15) extends to the gaseous atmosphere in the heating chamber (13) to introduce a device (32) which extends out of the trough (15) in order to avoid the gaseous atmosphere discharge from the heating chamber, a removable hood side wall construction (12), the lower end (33) of which extends down into the base circumferential trough (15) and by means (30) in the trough (15) which is between the lower end (33) of the removable hood-side wall construction and the trough (15) make a seal and the escape of the gaseous Prevent atmosphere from the heating chamber (13). 2. Furnace according to claim 1, characterized in that the base peripheral trough (15) has a bottom (27) and outer and inner side walls (28, 29) has that a device (31) extends into the trough through its bottom (27.) To the gaseous Introduce atmosphere into the heating chamber (13) and that a device (32) is calibrated from the trough through its bottom (27) extends through it to remove the gaseous atmosphere from the Discharge heating chamber. 3. Furnace according to claim 1 or 2, characterized in that the devices (31, 52) for introducing and discharging the gaseous atmosphere are arranged at a distance from the outer side wall (28) of the body (15). 009830/1286 4. Furnace according to one or more of the preceding claims, characterized in that the removable hood side wall structure (12) comprises a pair of has openings (34, 35) next to its lower end (33) and corresponding gear housing assemblies (36,36) surround at least the top and side portions of each opening and that each of the housing assemblies (36, 36 ') extend outwardly and downwardly from the removable hood side wall structure (12) into the Trough (15) extends below the surface of the sealant (30) located therein. 5. Furnace according to claim 4, characterized in that the removable Hood-side wall construction (12) a third housing arrangement (40) has on its inside which the bottom and the side parts of one (34) of the two openings (34,35) surrounds and that the third housing assembly (40) has an open upper end (41). 6. Furnace according to claim 5, characterized in that the third Gehäussanordnur.g (40) with its open upper end (41) is at a height _t which is at least as high as the top of the furnace base part. 009830/1286 7. Oven according to one or more of the preceding claims, characterized by a base casing (17) consisting of an outer peripheral side plate (45), an inner peripheral side plate (46) and one outer peripheral trough (50) adjacent the upper end of the outer peripheral side plate, means (53) providing a seal between the outer circumferential trough (50) and the outer circumferential side plate (45) -'- establishes an inner circumferential trough (51) adjacent the upper end of the inner circumferential side plate, means (54) which form a seal between the inner Circumferential trough and the inner peripheral side plate (46) manufactures a top plate (47) with an outer peripheral flange (48), which extends downwards into the outer circumference of the base casing extends and an inner circumferential flange (49) «the calibration down into the inner circumferential trough of the base casing and by means (52) 'in the outer and inner circumferential troughs the base cladding, which is between the outer circumferential flange part the top plate and the outer peripheral trough of the shell and between the inner peripheral flange portion the top plate and the inner circumferential well of the casing. 8. Oven according to claim 7 « characterized in that at least one of the means providing a seal between the outer Circumferential trough (50) and the outer circumferential side plate (45) and between the inner circumferential trough and the inner circumferential side plate forms, consists of a weld (53). 9. Oven according to claim 7, characterized in that at least one of the means for sealing between the outer circumferential trough and the outer circumferential side plate and between the inner circumferential trough and the inner circumferential side plate consists of a flange (54). which extends downward into the circumferential trough (51) near the top of one of the side panels (46). 10. Oven according to claim 7,: 8 or 9, characterized in that the Bäsis sheath (17) includes a bottom plate (44) disposed between the outer and inner peripheral side plate (45, 46) and in that a refractory Sookel (16) enclosed by the casing (17) · is located . ι · 11 furnace according to one of claims 7 to 10, characterized in that the sealing means (52) are in the outer and inner circumferential troughs (50, 51) of the jacket (17) is liquid at the furnace operating temperatures. . 12. Oven naoh Anapruoh 11, characterized in that the sealing means (52) are in the outer and inner circumferential troughs dtr sheathing is lead.