阅读说明：本技术 一种电热元件用镍铬高电阻电热合金的制备方法 (Preparation method of nickel-chromium high-resistance electrothermal alloy for electrothermal element ) 是由 卢金祥 于 2019-04-28 设计创作，主要内容包括：本发明涉及一种电热元件用镍铬高电阻电热合金的制备方法。所述电热元件用镍铬高电阻电热合金的制备方法,包括以下步骤：制备添加剂,添加剂中按质量分数配比为：氧化锗15%、二氧化硅22%,硼化钛8%、氧化铈7%、碳化硅42%、余量为氧化钴；在真空条件下熔化镍、铬金属并进行真空沸腾以形成镍铬合金液；将所述添加剂加入所述镍铬合金液中；将所述镍铬合金液静置后浇铸成铸锭；对所述铸锭进行退火处理并热轧成条状镍铬合金丝；以及利用卷绕机构将所述镍铬合金丝卷绕成圈状。所述电热元件用镍铬高电阻电热合金的制备方法制出的镍铬合金丝抗氧化性能较好且高温不易变脆。(The invention relates to a preparation method of a nickel-chromium high-resistance electrothermal alloy for an electrothermal element. The preparation method of the nickel-chromium high-resistance electrothermal alloy for the electrothermal element comprises the following steps: preparing an additive, wherein the additive comprises the following components in percentage by mass: 15% of germanium oxide, 22% of silicon dioxide, 8% of titanium boride, 7% of cerium oxide, 42% of silicon carbide and the balance of cobalt oxide; melting nickel and chromium metal under vacuum condition and boiling in vacuum to form a nichrome solution; adding the additive into the nickel-chromium alloy liquid; standing the nichrome liquid and then casting into a cast ingot; annealing the cast ingot and hot rolling the cast ingot into strip nickel-chromium alloy wires; and winding the nichrome wire into a coil shape by using a winding mechanism. The nickel-chromium alloy wire prepared by the preparation method of the nickel-chromium high-resistance electrothermal alloy for the electrothermal element has good oxidation resistance and is not easy to become brittle at high temperature.)

1. A preparation method of a nickel-chromium high-resistance electrothermal alloy for an electrothermal element is characterized by comprising the following steps:

preparing an additive, wherein the additive comprises the following components in percentage by mass: 15% of germanium oxide, 22% of silicon dioxide, 8% of titanium boride, 7% of cerium oxide, 42% of silicon carbide and the balance of cobalt oxide;

melting nickel and chromium metal under vacuum condition and boiling in vacuum to form a nichrome solution;

Adding the additive into the nickel-chromium alloy liquid;

standing the nichrome liquid and then casting into a cast ingot;

annealing the cast ingot and hot rolling the cast ingot into strip nickel-chromium alloy wires; and

and winding the nichrome wire into a coil shape by using a winding mechanism.

2. The method for preparing a nichrome high-resistance electrothermal alloy for an electrothermal element according to claim 1, wherein the winding mechanism comprises a delivery cylinder and a winding cylinder, the delivery cylinder and the winding cylinder are arranged at intervals, the delivery cylinder is cylindrical, and the nichrome wire is wound on the delivery cylinder.

3. The method for preparing the nickel-chromium high-resistance electrothermal alloy for the electrothermal element according to claim 2, wherein a rotary cylinder is arranged at the bottom of the conveying cylinder, and a mounting seat is arranged at the bottom of the rotary cylinder.

4. The method for preparing a nichrome high-resistance electrothermal alloy for an electrothermal element according to claim 3, wherein the mounting base is installed on the ground, the top surface of the mounting base is provided with an installation surface, and the rotary cylinder is installed on the installation surface.

5. The method of manufacturing a nichrome high resistance electrothermal alloy for an electric heating element according to claim 4, wherein the diameter of the take-up drum is larger than that of the delivery drum, and the delivery drum is made of a metal material.

6. The method of claim 5, wherein a heating element is disposed inside the delivery cylinder, and the heating element is in the form of a long strip.

7. The method of claim 6, wherein the heating element is coaxially disposed with the central axis of the feeding tube, and the height of the heating element is equal to the height of the feeding tube.

8. The method of claim 7, wherein the circumferential surface of the transfer cylinder is formed with a winding surface, the winding surface is provided with a plurality of heating holes, and the heating element is configured to release heat to the nichrome wire through the plurality of heating holes.

9. The method of claim 8, wherein the heating element is a cylindrical rod and the plurality of heating holes are circular holes.

10. The method of claim 9, wherein the plurality of heating holes extend through the sidewall of the delivery cylinder and are inclined with respect to the central axis of the delivery cylinder.

Technical Field

The invention relates to a preparation method of a nickel-chromium high-resistance electrothermal alloy for an electrothermal element.

Background

Nichrome is widely used in industry, and is widely used in industrial electric furnaces, household appliances, and far infrared devices. The nickel-chromium and elements such as iron, aluminum, silicon, carbon, sulfur and the like can be made into alloy nickel-chromium wires, have higher resistivity and heat resistance, and are electric heating elements of electric furnaces, electric irons, electric soldering irons and the like. However, as nichrome reaches higher temperatures, its oxidation resistance drops significantly. In contrast, ferrochromium alloys can withstand higher temperatures, but have the disadvantage of being brittle at high temperatures, so that neither alloy can meet the industrial requirements well.

Disclosure of Invention

Therefore, a need exists for a method for preparing a nickel-chromium high-resistance electrothermal alloy for an electric heating element, which has good oxidation resistance and is not easy to become brittle at high temperature.

A preparation method of a nickel-chromium high-resistance electrothermal alloy for an electrothermal element is characterized by comprising the following steps: preparing an additive, wherein the additive comprises the following components in percentage by mass: 15% of germanium oxide, 22% of silicon dioxide, 8% of titanium boride, 7% of cerium oxide, 42% of silicon carbide and the balance of cobalt oxide; melting nickel and chromium metal under vacuum condition and boiling in vacuum to form a nichrome solution; adding the additive into the nickel-chromium alloy liquid; standing the nichrome liquid and then casting into a cast ingot; annealing the cast ingot and hot rolling the cast ingot into strip nickel-chromium alloy wires; and winding the nichrome wire into a coil shape by using a winding mechanism.

In one embodiment, the winding mechanism comprises a conveying cylinder and a winding cylinder, the conveying cylinder and the winding cylinder are arranged at intervals, the conveying cylinder is cylindrical, and the nichrome wire is wound on the conveying cylinder.

In one embodiment, a rotary air cylinder is arranged at the bottom of the conveying cylinder, and a mounting seat is arranged at the bottom of the rotary air cylinder.

In one embodiment, the mounting seat is mounted on the ground, the top surface of the mounting seat is provided with a mounting surface, and the rotary cylinder is mounted on the mounting surface.

In one embodiment, the diameter of the take-up drum is greater than the diameter of the delivery drum, which is made of a metallic material.

In one embodiment, the inside of the transport cylinder is provided with a heating element, which is elongated.

In one embodiment, the heating element is arranged coaxially with the central axis of the delivery cylinder, and the height of the heating element is equal to the height of the delivery cylinder.

In one embodiment, a winding surface is formed on the circumferential surface of the conveying cylinder, a plurality of heating holes are formed in the winding surface, and the heating element is used for releasing heat to the nichrome wire through the plurality of heating holes.

In one embodiment, the heating element is a cylindrical rod, and the plurality of heating holes are all circular holes.

In one embodiment, the plurality of heating holes each penetrate through a side wall of the delivery cartridge and extend obliquely with respect to a central axis of the delivery cartridge.

The additive is arranged in the preparation method of the nickel-chromium high-resistance electrothermal alloy for the electrothermal element, silicon dioxide and germanium dioxide are used for improving resistivity, cerium oxide is used for improving dispersion capacity, and boron element in titanium boride is used for refining grains, and particularly, the silicon carbide in the additive can play a role in dispersion strengthening of the nickel-chromium alloy, so that dislocation and slippage are blocked at high temperature, the strength of the nickel-chromium alloy at high temperature is effectively improved, and the high-temperature oxidation resistance of the nickel-chromium alloy is improved, so that the nickel-chromium alloy prepared by the preparation method has high oxidation resistance, and the nickel-chromium alloy is not easy to become brittle at high temperature.

Drawings

FIG. 1 is a flow chart illustrating the steps of one embodiment of a method for making a nickel chromium high resistance electrothermal alloy for an electrical heating element;

fig. 2 is a perspective view of a partial structure of a winding mechanism according to an embodiment.

Fig. 3 is a schematic perspective view of a transferring assembly and a winding assembly according to an embodiment.

Fig. 4 is a perspective view of the transfer assembly and the winding assembly shown in fig. 3 from another view angle.

FIG. 5 is a flowchart illustrating steps of a finishing step according to an embodiment.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The invention relates to a preparation method of a nickel-chromium high-resistance electrothermal alloy for an electrothermal element, which comprises the following steps: preparing an additive, wherein the additive comprises the following components in percentage by mass: 15% of germanium oxide, 22% of silicon dioxide, 8% of titanium boride, 7% of cerium oxide, 42% of silicon carbide and the balance of cobalt oxide; melting nickel and chromium metal under vacuum condition and boiling in vacuum to form a nichrome solution; adding the additive into the nickel-chromium alloy liquid; standing the nichrome liquid and then casting into a cast ingot; annealing the cast ingot and hot rolling the cast ingot into strip nickel-chromium alloy wires; and winding the nichrome wire into a coil shape by using a winding mechanism.

Referring to fig. 1, a method for preparing a nichrome high-resistance electrothermal alloy for an electrothermal element includes the following steps:

in step S101, an additive is prepared, wherein the additive comprises the following components in percentage by mass: 15% of germanium oxide, 22% of silicon dioxide, 8% of titanium boride, 7% of cerium oxide, 42% of silicon carbide and the balance of cobalt oxide;

in step S102, melting nickel and chromium metals under vacuum and boiling them in vacuum to form a nichrome solution;

in step S103, adding the additive to the nichrome solution;

in step S104, standing the nichrome liquid and casting the nichrome liquid into a cast ingot;

in step S105, annealing the ingot and hot rolling the ingot into a strip-shaped nichrome wire; and

in step S106, the nichrome wire is wound in a coil shape by the winding mechanism 100.

The additive is arranged in the preparation method of the nickel-chromium high-resistance electrothermal alloy for the electrothermal element, silicon dioxide and germanium dioxide are used for improving resistivity, cerium oxide is used for improving dispersion capacity, and boron element in titanium boride is used for refining grains, and particularly, the silicon carbide in the additive can play a role in dispersion strengthening of the nickel-chromium alloy, so that dislocation and slippage are blocked at high temperature, the strength of the nickel-chromium alloy at high temperature is effectively improved, and the high-temperature oxidation resistance of the nickel-chromium alloy is improved, so that the nickel-chromium alloy prepared by the preparation method has high oxidation resistance, and the nickel-chromium alloy is not easy to become brittle at high temperature.

For example, referring to fig. 2, the nichrome wire is a nichrome high-resistance electrothermal alloy wire, in order to facilitate winding of the wound nichrome high-resistance electrothermal alloy wire into a nichrome high-resistance electrothermal alloy wire coil with a larger diameter, the winding mechanism 100 includes a conveying cylinder 20 and a winding cylinder 30, the conveying cylinder 20 and the winding cylinder 30 are arranged at intervals, and the conveying cylinder 20 is cylindrical and is wound with the nichrome high-resistance electrothermal alloy wire. The bottom of the conveying cylinder 20 is provided with a rotary cylinder 21, and the bottom of the rotary cylinder 21 is provided with a mounting seat 22. The mounting seat 22 is mounted on the ground, a mounting surface 23 is arranged on the top surface of the mounting seat 22, and the rotary cylinder 21 is mounted on the mounting surface 23. The diameter of the winding drum 30 is larger than that of the delivery drum 20, and the delivery drum 20 is made of a metal material. The inner side of the conveying cylinder 20 is provided with a heating element 25, and the heating element 25 is long. The heating element 25 is arranged coaxially with the central axis of the conveying cylinder 20, and the height of the heating element 25 is equal to that of the conveying cylinder 20. A winding surface 26 is formed on the circumferential surface of the conveying cylinder 20, a plurality of heating holes are formed on the winding surface 26, and the heating element 25 is used for releasing heat to the nichrome high-resistance electrothermal alloy wire through the plurality of heating holes. The heating element 25 is a cylindrical rod, and the plurality of heating holes are circular holes. The plurality of heating holes penetrate through the side wall of the conveying cylinder 20 and extend obliquely relative to the central axis of the conveying cylinder 20. Through setting up carry a section of thick bamboo 20 with receipts reel 30 to the great nichrome high resistance electrothermal alloy wire coil of diameter is twined into to the convenience with less nichrome high resistance electrothermal alloy wire coil in order selling or facilitate the use to specific application.

For example, referring to fig. 3 and 4 together, in order to improve the winding efficiency, the winding mechanism 100 further includes a winding assembly 40 and a transfer assembly 50, and the winding assembly 40 and the delivery cylinder 20 are disposed at an interval for winding the nichrome wire coil. The winding assembly 40 comprises a winding motor 41, a triangular cylinder 42, the winding cylinder 30 and a preheating rod (not shown), the triangular cylinder 42 is connected to the winding motor 41, the cross section of the triangular cylinder 42 is triangular, a plurality of first preheating holes 421 are formed in the triangular cylinder 42, three arc-surface sliding strips are arranged on the circumferential surface of the triangular cylinder 42 and are respectively arranged at three vertex angles of the triangular cylinder 42, and the arc-surface sliding strips extend along the length direction of the triangular cylinder 42. The peripheral surface of the triangular tube 42 constitutes a first winding surface 422. The winding drum 30 is in a circular cylinder shape, the winding drum 30 is sleeved on the triangular drum 42 in a lifting manner, and the inner diameter of the winding drum 30 is equal to the diameter of a circumscribed circle of the triangular drum 42. The inner side of the winding drum 30 is concavely provided with three strip-shaped grooves, and three cambered surface sliding strips of the triangular drum 42 are respectively arranged in the three strip-shaped grooves in a sliding manner. The circumferential surface of the winding drum 30 forms a second winding surface 32, and the winding drum 30 is provided with a plurality of second preheating holes 325. The preheating rod is arranged in the triangular cylinder 42 and used for preheating the triangular cylinder 42 and the winding cylinder 30 so as to improve the heating temperature of the nickel-chromium high-resistance electric heating alloy wire during winding, so that the flexibility is enhanced, and the nickel-chromium high-resistance electric heating alloy wire is convenient to deform and then more conveniently wind on the winding assembly 40. Through setting up triangle-shaped section of thick bamboo 42 with receive the reel 30, can twine nickel-chromium high resistance electric heat alloy wire in more conveniently receive the reel 30 or on the triangle-shaped section of thick bamboo 42 to form the nickel-chromium high resistance electric heat alloy wire coil of different shapes, for example, form circular coil or form triangle-shaped coil, in order to accord with different use scenes. The triangular coil wound on the triangular cylinder 42 is convenient to cut when in use, namely the triangular coil is cut into a strip of nichrome high-resistance electrothermal alloy wire from two adjacent corners of the triangle, so that the subsequent use is convenient. The three arc-shaped sliding bars facilitate the winding drum 30 to be slidably arranged on the triangular cylinder 42, and simultaneously facilitate the reduction of the shearing stress of the nickel-chromium high-resistance electrothermal alloy wire wound on the triangular cylinder 42, so as to prevent the nickel-chromium high-resistance electrothermal alloy wire from being damaged. For example, the winding drum 30 is connected to the triangular drum 42 through an adjusting member, and when the heights of the circular coil and the triangular coil need to be adjusted, the height of the winding drum 30 relative to the triangular drum 42 can be adjusted through the adjusting member.

For example, referring to fig. 3 and 4, in some cases, a circular coil can be wound directly on the take-up drum 30 alone, or a triangular coil can be wound directly on the triangular drum 42 alone. In order to form two coils on the winding drum 30 simultaneously, the second winding surface 32 of the winding drum 30 includes an upper winding surface 321 and a lower winding surface 322 connected to each other. The transfer component 50 is arranged between the winding component 40 and the conveying cylinder 20, and is used for transferring and guiding the two nichrome high-resistance electrothermal alloy wires conveyed by the conveying cylinder 20 to the upper winding surface 321 and the lower winding surface 322 respectively. Transfer subassembly 50 includes base 51, lift cylinder 52, lift arm 53, two transfer rings 54 and separating wheel 55, base 51 set up in mount pad 22 with between the rolling motor 41, the one end of base 51 is provided with pulling chain 515, the end connection of pulling chain 515 to on the shell of rolling motor 41, pulling chain 515 is used for adjusting base 51 with distance between the rolling motor 41 to change transfer transmission distance. The lifting cylinder 52 is mounted on the base 51, the lifting arm 53 is mounted on the lifting cylinder 52 and parallel to the central axis of the winding drum 30, and the two middle rotating rings 54 are disposed on the lifting arm 53 at intervals and aligned with the upper winding surface 321 and the lower winding surface 322, respectively. The central axes of the two middle rotary rings 54 are perpendicular to the central axis of the winding drum 30, and the central axes of the middle rotary rings 54 are tangent to the second winding surface 32, so that the nickel-chromium high-resistance electrothermal alloy wire conveyed out by the middle rotary rings 54 can be smoothly wound on the second winding surface 32. The inner diameter of the middle rotating ring 54 is equal to the diameter of the nickel-chromium high-resistance electric heating alloy wire, and the two middle rotating rings 54 are respectively used for the two nickel-chromium high-resistance electric heating alloy wires to penetrate through. The separating wheel 55 is rotatably mounted on the lifting arm 53 through a mounting bracket 56, the outer diameter of the separating wheel 55 is larger than the inner diameter of the middle rotating ring 54, the separating wheel 55 is aligned with the upper winding surface 321, the rotation axis of the separating wheel 55 is perpendicular to the rotation axis of the winding drum 30, and the central axis of the separating wheel 55 is perpendicular to the central axis of the winding drum 30. A guide ring surface 555 is formed on the periphery of the separating wheel 55, the top of the guide ring surface 555 is aligned with the top edge of the upper winding surface 321 and used for abutting and guiding one nichrome high-resistance electric heating alloy wire to the upper winding surface 321, and the bottom of the guide ring surface 555 is aligned with the top edge of the lower winding surface 322 and used for abutting and guiding another nichrome high-resistance electric heating alloy wire to the lower winding surface 322. That is, the top and the bottom of the guide ring 555 are respectively used for guiding the nichrome high-resistance electrothermal alloy wire to be wound on the upper winding surface 321 and the lower winding surface 322. The top and bottom of the guide ring 555 are adjacent to the two mid-rotation rings 54, respectively. The mounting bracket 56 is provided with a sensor for sensing the rotation angle of the separating wheel 55, and the sensor is electrically connected to the lifting cylinder 52. When in use, the conveying cylinder 20 conveys two nichrome high-resistance electrothermal alloy wires into the two middle rotating rings 54, and the end parts of the two nichrome high-resistance electrothermal alloy wires are respectively wound on the upper winding surface 321 and the lower winding surface 322. The winding motor 41 drives the winding drum 30 to rotate so as to wind and pull the two nichrome high-resistance electrothermal alloy wires to implement winding operation. The lifting cylinder 52 drives the two middle rotating rings 54 and the separating wheel 55 to descend through the lifting arm 53, so that the nickel-chromium high-resistance electrothermal alloy wires are wound on the upper winding surface 321/the lower winding surface 322 from top to bottom circle by circle, and the two nickel-chromium high-resistance electrothermal alloy wires are wound at the same time. In the process, the top and the bottom of the separating wheel 55 are equally pulled by the two nichrome high-resistance electrothermal alloy wires, and do not rotate greatly. When the nichrome high-resistance electric heating alloy wire on the lower winding surface 322 moves downwards to the first winding surface of the triangular cylinder 42, because the circumference of the first winding surface of the triangular cylinder 42 is smaller than the circumference of the second winding surface of the circular cylinder, in the subsequent rotation process, the movement speed of the nichrome high-resistance electric heating alloy wire at the top of the partition wheel 55 is high, and the movement speed of the nichrome high-resistance electric heating alloy wire at the bottom of the partition wheel 55 is low, at this time, the two nichrome high-resistance electric heating alloy wires generate friction resistance by using the speed difference between the two wires, the friction resistance drives the partition wheel 55 to rotate, and when the sensor senses that the rotation of the partition wheel 55 exceeds 90 degrees, a stop signal is sent to the lifting motor to stop the lifting motor. For example, when the partition is rotated 90 degrees, the nichrome high resistance electrothermal alloy rotates one turn around the triangular cylinder 42. By providing the relay assembly 50, it is convenient to wind a small coil of nichrome high resistance alloy on the delivery cylinder 20 onto the take-up cylinder 30 or the triangular cylinder 42 to form a larger diameter coil. Two large-diameter coils with smaller height can be wound simultaneously by the take-up reel 30. The partition wheel 55 is arranged to avoid mutual winding of two nickel-chromium high-resistance electrothermal alloys, and meanwhile, the partition wheel 55 can be used for rotating to detect whether the nickel-chromium high-resistance electrothermal alloy wire is wound or not, so that the lifting motor is controlled to stop.

For example, referring to fig. 5, the coiling mechanism 100 is used to coil the nichrome wire into a coil shape, specifically: the nichrome wire is wound in a coil shape by the transfer cylinder 20 of the winding mechanism 100. The preparation method of the nickel-chromium high-resistance electrothermal alloy for the electrothermal element further comprises a post-finishing step, wherein the post-finishing step specifically comprises the following steps:

in step S107, the height of the winding drum 30 relative to the triangular drum 42 is adjusted by the adjusting member;

in step S108, the preheating bar is used to preheat the triangular tube 42 and the winding tube 30;

in step S109, the conveying cylinder 20 conveys two nichrome high-resistance electrothermal alloy wires into the two middle rotating rings 54, and the end portions of the two nichrome high-resistance electrothermal alloy wires are respectively wound on the upper winding surface 321 and the lower winding surface 322 of the winding cylinder 30;

in step S110, the top of the guide ring surface 555 of the separating wheel 55 aligns with the top edge of the upper winding surface 321, and supports and guides one of the nichrome high-resistance electrothermal alloy wires to the upper winding surface 321, the bottom of the guide ring surface 555 aligns with the top edge of the lower winding surface 322, and supports and guides the other nichrome high-resistance electrothermal alloy wire to the lower winding surface 322;

In step S111, the winding motor 41 drives the winding drum 30 to rotate to wind and pull the two nichrome high-resistance electrothermal alloy wires to perform winding operation, and the lifting cylinder 52 drives the two middle rotating rings 54 and the separating wheel 55 to descend through the lifting arm 53, so that the two nichrome high-resistance electrothermal alloy wires are respectively wound on the upper winding surface 321 and the lower winding surface 322 from top to bottom one by one, thereby realizing simultaneous winding of the two nichrome high-resistance electrothermal alloy wires;

in step S112, after the nichrome high-resistance electrothermal alloy wire on the lower winding surface 322 moves down to the first winding surface of the triangular cylinder 42, the two nichrome high-resistance electrothermal alloy wires generate frictional resistance by using the speed difference between the two, and the frictional resistance drives the partition wheel 55 to rotate;

in step S113, when the sensor senses that the divider wheel 55 rotates more than 90 degrees, a stop signal is sent to the lift motor to stop the lift motor; and

in step S114, another nichrome high-resistance electrothermal alloy wire is wound around the triangular tube 42.

In the finishing step, by providing the transfer assembly 50, a small coil of the nichrome high-resistance electrothermal alloy on the delivery cylinder 20 can be conveniently wound on the take-up cylinder 30 or the triangular cylinder 42 to form a coil with a larger diameter. Two large-diameter coils with smaller height can be wound simultaneously by the take-up reel 30. The partition wheel 55 is favorable for avoiding the mutual winding of two nickel-chromium high-resistance electrothermal alloys, and can detect whether the winding of the nickel-chromium high-resistance electrothermal alloy wire is completed or not by utilizing the rotation of the partition wheel 55, so as to control the stop of the lifting motor.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.