JP2695695B2 - Heater roll - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heater roll such as a ringer roll in a steelmaking machine process facility or a heating roll in a continuous annealing furnace.

[Conventional technology]

As shown in FIGS. 6 and 7, the conventional heater roll closes on the central axis of the roll 01 or the inner surface of the roll 01 so as to contact the heat medium 03 sealed inside the hollow roll 01. A heater 02 is provided. In addition, reference numeral 04 denotes a plate as a transfer material that is passed through the heater roll and exchanges heat with the heater roll.

[Problems to be solved by the invention]

In the above-mentioned conventional heater roll, when the heater is disconnected and needs to be replaced, it is necessary to expose the heat medium to the atmosphere. For this purpose, it is necessary to remove the roll from the line and change the posture so that the heat medium does not leak. When a heating medium having a vapor pressure lower than the atmospheric pressure is sealed in a vacuum state at room temperature, it is necessary to vacuum the inside of the roll again after replacing the heater. These result in high costs for maintenance of the rolls.

Further, in the above-described conventional heater roll, due to the heat load received from the plate and the adhering liquid when the plate as a conveying material is passed, a difference occurs between the temperature of the contact area and other parts in the axial direction of the roll, A uniform heat exchange with the plate cannot be performed, and a thermal crown is generated in the roll due to a temperature difference in the roll axial direction, so that the pressing pressure against the plate is not uniform in the roll axial direction.

In particular, in the case of a heater roll (ringer roll) used in a process line of an iron making machine for wiping liquid adhering to a steel sheet at a temperature, contact of the steel sheet in a roll axis direction is required to pass a high-temperature steel sheet. The temperature of the roll rises remarkably only in the region and the temperature of the roll end is low, so that the above-mentioned problem becomes remarkable and the wiping ability of the liquid is reduced, but in addition, the temperature of the roll end is wiped. However, there is a disadvantage that the solidified material accumulates at the end of the roll and continuous operation becomes impossible.

[Means for solving the problem]

 The heater roll of the present invention takes the following measures.

(1) In a heater roll having a heating medium sealed in a hollow roll and having a heater for heating the same, a pocket openable to the atmosphere is provided in the roll, and the low melting point metal and the heater are accommodated in the pocket. .

(2) In a heater roll having a heater for enclosing a heating medium in a hollow roll and heating the same, the heater is arranged on the center axis of the roll, and a part of the outer periphery of the cross section of the heating medium is used as the heating medium. The heating medium vapor mole fraction in the gas phase in the roll is 80% in the temperature range during use of the roll.
% Or more.

(3) In the heater roll of (2), a pocket that accommodates the low melting point metal and the heater instead of the heater and that can be opened to the atmosphere is disposed on the center axis of the roll.

[Action]

In the present invention of (1), the low melting point metal is melted by the heater, and the heat generated by the heater is transmitted to the heat medium through the pocket, so that the roll is heated with high heat transfer efficiency.

When replacing the heater, the roll is heated to a temperature equal to or higher than the melting point of the low-melting metal, and the melted upper pocket is opened to the atmosphere, whereby the heater is taken out of the roll. Therefore, the heater can be easily replaced independently of the heat medium without releasing the heat medium in the roll to the atmosphere.
This also allows the heater to be replaced while the heater roll remains online.

In the present invention (2), the heat medium wets at least a part of the outer periphery of the cross section of the heater, and the heat medium is heated to substantially the same temperature in the axial direction of the roll by the heater. When the temperature rises partially due to the thermal load from the plate passing through the roll, the heat medium heated by the heater evaporates in the region where the temperature rises, and the vapor flows in the axial direction of the roll and the temperature rises. Condenses on the inner surface of the lower roll shell and gives this partial heat of condensation. In this way, the heat medium has a heat transport function as a heat pipe, and the temperature of all portions inside the roll to which the heat medium vapor can reach is made uniform. Moreover, in the gas phase in the roll, the heat medium vapor mole fraction is 80% or more, so that the condensation of the heat medium vapor on the low-temperature side wall surface of the roll is not hindered, and the temperature of the roll is uniform. Will be fully achieved. As a result, the generation of the thermal crown of the roll is prevented, the pressing pressure against the plate becomes constant, the temperature of the roll end rises, and the solidification of the liquid wiped from the plate is prevented.

Still further, by operating the heater before passing through the roll, the entire area of the roll is uniformly preheated to a predetermined temperature.

The present invention of (3) employs the heater of (1) of the present invention and a pocket containing a low-melting-point metal, instead of the heater of the present invention of (2). The effects of (1) and (2) can be achieved together.

〔Example〕

 A first embodiment of the present invention will be described with reference to FIG.

This embodiment is a ringer roll for wiping molten salt adhered to a steel plate at a temperature of about 450 ° C., and an inner cylinder 5 extending the entire length in the axial direction of the roll 1 is provided at the center of the cross section inside the hollow roll 1. Roll 1 is provided on one body, and potassium is sealed as a heat medium 3 in a space between inner cylinder 5 and roll 1. Inside the inner cylinder 5, a heater 2 and a wood metal (Bi 55%, Pb 45%) 4 as a low melting point metal are accommodated. One end of the inner cylinder 5 is closed by the roll 1 and the other end is open. This opening is closed by a lid 6 attached to the inner cylinder 5 by bolts 8 to form a pocket. Reference numeral 7 denotes an electric wire for supplying a current to the heater 2, and reference numeral 20 denotes a steel plate through which the heater roll passes.

A heat medium 3 is sealed in the roll 1 so as to wet at least a part of the outer circumference of the cross section of the inner cylinder 5. The vapor mole fraction of the heat medium 3 in the phase is 80% in the temperature range during roll use.
It is set so that it becomes above.

In assembling the present embodiment, the heat medium 3 is sealed between the roll 1 and the inner cylinder 5, the wood metal 4 is inserted into the inner cylinder 5, and the melting point of the wood metal 4 (124 ° C.) The heater 2 heated above (for example, 200 ° C.) is inserted into the inner cylinder 5. The wood metal 4 is thereby melted and penetrates into the gap between the inner cylinder 5 and the heater 2no. In this state, cover 6 is
The inner cylinder 5 is attached to the end face of the inner cylinder 5 to close the inner cylinder 5.

In the present embodiment, when the heater 2 is energized, the wood metal 4 as a low melting point metal is first melted, and this is used as an intermediate heat medium to heat the heat medium 3 in the space between the inner cylinder 5 and the roll 1. Then, the roll 1 is heated. Since the wood metal 4 penetrates into the gap between the heater 2 and the inner cylinder 5 as described above, heat transfer with good heat transport efficiency is performed.

When replacing the heater 2, the entire roll is heated to a temperature equal to or higher than the melting point (124 ° C.) of the wood metal 4 to melt the metal 4. In this state, after removing the lid 6, the heater 2 can be taken out of the inner cylinder 5. At this time, the heat medium 3 is not exposed to the atmosphere, the heat medium 3 does not leak, and there is no need to evacuate after replacing the heater.

Further, since at least a part of the outer periphery of the cross section of the inner cylinder 5 is wet by the heat medium 3, the heat medium 3 is heated by the heater 2 to substantially the same temperature in the axial direction of the roll 1. When the roll 1 receives a heat load by the passing steel plate 20 and partially rises in temperature, in the region where the temperature rises, the heating medium 3 heated by the heater 2 as described above evaporates and its vapor Flows in the axial direction of the roll 1 and condenses on the inner surface of the roll shell where the temperature is low, and this portion receives heat of condensation. In this way, the heat medium 3 performs a heat transport function as a heat pipe, and the temperature of all portions inside the roll 1 to which the heat medium vapor can reach is made uniform.

Moreover, in the gas phase inside the roll 1, the molar fraction of the heating medium vapor is 80% or more, and the condensation of the heating medium vapor on the low-temperature side wall surface of the roll is not hindered. Temperature uniformization can be sufficiently performed.

As described above, by making the temperature in the axial direction of the roll 1 uniform, the occurrence of a thermal crown on the roll 1 is suppressed, the pressing pressure against the steel plate 20 to be passed is constant, and the wiping ability of the adhered liquid is achieved. Does not decrease. Further, by making the temperature in the axial direction of the roll 1 uniform, the temperature of the end portion of the roll 1 rises and the liquid wiped is prevented from solidifying.

Further, by operating the heater 2 before passing the roll 1 through the plate, the roll 1 can be preheated uniformly to a predetermined temperature in the axial direction.

 A second embodiment of the present invention will be described with reference to FIG.

This embodiment is a ringer roll for wiping molten salt adhered to a steel plate at a temperature of about 450 ° C. similarly to the first embodiment. And a sheath heater 10 is arranged on the center axis of the roll 1. Sheath heater 10
Is connected to a power supply 12 by an electric wire 11.

Further, the heat medium 3 in the hollow roll 1 is filled with 50% of the inner volume of the space in the hollow roll 1 so as to wet about half of the outer periphery of the cross section of the sheath heater (the vapor pressure of potassium at 20 ° C. is 0.0001). Torr or less). Gases other than the heat medium in the hollow roll 1 are exhausted, and the vapor pressure of components other than the heat medium in the gas phase in the roll 1 is set to be 0.01 Torr or less at 20 ° C.

In this embodiment, since about half of the outer circumference of the cross section of the sheath heater 10 is wet by the heat medium 3, the sheath heater
By means of 10, the heating medium 3 is heated to substantially the same temperature in the axial direction of the roll 1. When the roll 1 receives a heat load from the passing steel plate 20 and partially rises in temperature, in the region where the temperature rises, the heating medium 3 heated by the sheath heater 10 as described above evaporates and its vapor Flows in the axial direction of the roll 1 and condenses on the inner surface of the roll shell having a low temperature, and this portion receives heat of condensation. In this way, the heat medium 3 performs a heat transport function as a heat pipe, and the temperature of all portions inside the roll 1 to which the heat medium vapor can reach is made uniform.

Moreover, in the present embodiment in which the steel sheet having a temperature of about 450 ° C. is passed as described above, the roll temperature is about 400 ° C., and the vapor pressure of potassium as a heat medium rises to 4 Torr, whereas the pressure of potassium other than potassium is increased. The vapor pressure is And the heat medium vapor mole fraction is 0.995. Therefore, the condensation of the heat medium vapor on the low-temperature wall surface of the roll is not hindered by other components, and the temperature inside the roll 1 can be sufficiently uniformized.

As described above, in the present embodiment, by making the temperature in the axial direction of the roll 1 uniform, the occurrence of a thermal crown on the roll 1 is suppressed, and the pressing pressure against the steel sheet 20 to be passed becomes constant. The wiping ability of the adhered liquid does not decrease. Further, by making the temperature in the axial direction of the roll 1 uniform, the temperature at the end of the roll 1 increases, and the liquid wiped does not solidify.

Further, by operating the sheath heater 10 before passing the steel plate 20, the roll can be preheated uniformly to a predetermined temperature in the axial direction.

 Hereinafter, experimental examples of the present invention will be described.

Outer diameter 100 mm according to the second embodiment shown in FIG. 2
Use a device consisting of a roll with a diameter of φ, an inner diameter of 80 mm, and a length of 2000 mm.
% Encapsulated. The pressure in the gas phase of components other than potassium in the gas phase was set to 0.01 Torr or less. The temperature distribution of the roll when a steel plate of 450 ° C. is passed through the roll at 100 mpm is shown by a curve a in FIG. On the other hand, the curve b shows the temperature distribution in the conventional hollow ringer roll. As a result, according to the present invention, the temperature difference in the roll axis direction is reduced to 1/3 or less of the conventional temperature, and the thermal crown is also reduced to 1/3 or less. In addition, the roll end of the conventional roll was below the solidification point c of the molten salt, but became higher than that, and it was confirmed that the solidification of the salt at the roll end was eliminated.

FIG. 4 shows the maximum temperature difference in the roll axis direction when the amount of the heat medium is changed in the experimental example of the present invention. When the heating medium no longer wets the heater, the electric heat from the heater to the heating medium sharply decreases, and the temperature difference between the rolls increases.

FIG. 5 shows the relationship between the heat medium vapor mole fraction in the gas phase in the roll and the maximum temperature difference in the roll axis direction in the experimental example of the present invention. When the ratio of the vapor other than the heat medium vapor is 20% or more, the heat transfer amount is reduced because the heat medium vapor is prevented from condensing on the low-temperature side wall surface, and the temperature difference between the rolls is increased.

〔The invention's effect〕

Conventionally, when replacing the heater of the heater roll, the roll was removed from the line, and after replacing the heater, it was checked that there was no leakage of the heat medium from the roll and returned to the line again, so a great deal of cost was required. According to the present invention, the low melting point metal and the heater are housed in a pocket openable to the atmosphere in the roll shell, so that the heater can be replaced while being online regardless of the heat medium. And maintenance costs can be reduced.

According to the invention of claim (2), the temperature in the axial direction of the roll can be made uniform, and the thermal crown of the roll can be reduced. Thereby, when pinching the wiping member, wiping can be performed uniformly in the width direction of the plate, solidification of the wiping liquid to the roll end can be prevented, and maintenance of the roll can be eliminated.

Further, the present invention of claim (3) provides the above-mentioned claim (1).
And (2) the effects of the present invention can be obtained together.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a ringer roll according to a first embodiment of the present invention, FIG. 2 is an explanatory view of a ringer roll according to a second embodiment of the present invention, and FIG. FIG. 4 is a graph showing the temperature distribution in the axial direction of a conventional roll, FIG. 4 is a graph showing the relationship between the maximum temperature difference in the axial direction of the roll and the volume ratio of filled heat medium in the experimental example of the present invention, and FIG. FIG. 6 and FIG. 7 are graphs showing the relationship between the heat medium vapor mole fraction and FIG. 6 and FIG. 1 ... roll, 2 ... heater, 3 ... heating medium, 4 ... wood metal, 5 ... inner cylinder, 6 ... lid, 10 ... sheath heater, 20 ... steel plate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuyoshi Takeoka 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Akira Kishida 1 Kawasakicho, Chiba-shi, Chiba Kawasaki Inside the Chiba Works, Steel Works Ltd. (72) Harumasa Muramoto, Inventor 1, Kawasaki-cho, Chiba City, Chiba Prefecture Inside the Chiba Works, Kawasaki Works (56) References JP-A-3-4480 (JP, A) JP-A Sho 56-143691 (JP, A) JP-A-62-254383 (JP, A) JP-A-4-32885 (JP, A)

Claims (3)

(57) [Claims] 1. A heater roll in which a heating medium is sealed in a hollow roll and a heater for heating the hollow medium is provided, a pocket openable to the atmosphere is provided in the roll, and a low melting point metal and a heater are provided in the pocket. A heater roll that is housed. 2. A heater roll having a heater for enclosing a heat medium in a hollow roll and heating the heat medium, wherein the heater is disposed on the center axis of the roll, and the heat medium is formed on a part of the outer periphery of the cross section of the heater. A heater roll in which the heat medium is sealed more than the lower limit that the heat medium wets, and the heat medium vapor mole fraction in the gas phase in the roll is 80% or more in a temperature range during use of the roll. 3. A heater roll according to claim 2, wherein a pocket containing a low-melting metal and a heater and capable of being opened to the atmosphere is arranged on the center axis of the roll in place of the heater. .