Needle valve

Abstract

This invention provides a needle valve used in coke ovens that eliminates the need for disassembly and cleaning, extends the lifespan of its components, and reduces the frequency of component replacement. [Solution] A conical needle 2 is attached to the tip end of the valve stem 4 that constitutes the needle valve 1, a rotating handle 10 is attached to the handle end of the valve stem 4, a male thread 8 is formed on the outer circumference of the handle end of the valve stem 4, the male thread 8 is screwed into a female thread formed in a small diameter hole of the boss portion of the housing 3, a cylindrical casing 14 through which the valve stem 4 is inserted is fixed to the housing 3, a female thread for attachment to a gas distribution branch pipe is formed in the housing 3, and one or more sealing materials 13 are disposed between the outer circumference of the valve stem 4 that does not have male threads 7 and 8 and the inner circumference of the hollow hole 15 of the cylindrical casing 14.

Description

Technical Field

[0001] The present invention relates to a needle valve provided in a fuel gas supply passage of a coke oven.

Background Art

[0002] A coke oven installed in a steelworks includes a plurality of carbonization chambers into which coal, which is a raw material for coke, is charged, a combustion chamber for heating the carbonization chambers, and a regenerator disposed at the bottom. The fuel gas supplied from the regenerator to each combustion chamber burns while keeping the combustion chamber temperature constant. As a result, the coking reaction of the coal charged into the carbonization chamber is uniformly maintained, and coke of stable quality can be obtained. As a means for supplying an appropriate amount of fuel gas to the regenerator, for example, an underjet method is adopted in which pipes are piped to each regenerator, and the flow rates of fuel gas, air, etc. are controlled by a flow rate adjusting mechanism provided in the pipe line.

[0003] In a coke oven adopting the underjet method, the regenerator is communicated with a plurality of rows of combustion chambers arranged at the upper part of the furnace body. At the lower part of the regenerator, a fuel gas supply system and an air supply system are arranged together, and a duct directly connected to the fuel gas supply system extends along the furnace length direction. A plurality of underjet pipes reaching the lower part of each regenerator are branched and provided in the distribution branch pipes branched from the duct. Then, the flow rate of the fuel gas sent downward to each regenerator is adjusted by a needle valve for flow rate adjustment attached to the underjet pipe (see Patent Document 1, FIG. 5).

[0004] On the other hand, an annular plate may be attached to the underjet pipe and used as an orifice without using a needle valve. In this case, the flow rate of the fuel gas flowing from the gas distribution branch pipe into the underjet pipe is adjusted by the orifice diameter. Therefore, when changing the flow rate, it is necessary to replace the orifice with a different hole diameter, which requires complicated work.

[0005] For these reasons, the mainstream approach is to install a needle valve for flow rate adjustment in the fuel gas supply path to regulate the flow rate of fuel gas sent to each heat storage chamber. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Special Publication No. 6-99685 [Overview of the project] [Problems that the invention aims to solve]

[0007] In the coke oven flow rate control device described in Patent Document 1, when a rotary handle attached to the lower end of the spindle (valve stem) is operated, the spindle is pitch-feeded within the support frame, causing a conical needle fixed to the tip of the spindle to move closer to or further away from the valve seat. Therefore, the flow rate of the fuel gas can be adjusted by rotating the handle.

[0008] However, the male thread of the spindle, which engages with the adjustment nut located at the tip of the support frame, is positioned exposed inside the gas distribution branch pipe, thus being exposed to the dust and other contaminants within the gas distribution branch pipe. As a result, after prolonged operation, dust and other contaminants could adhere to the surface of the male thread of the spindle, making it difficult to adjust the spindle's pitch. In such cases, it becomes necessary to remove the needle valve from the gas distribution branch pipe, disassemble it, and clean it. Furthermore, if rust is present in addition to dust accumulation, parts replacement may be necessary.

[0009] This invention solves the problems of the prior art and aims to provide a needle valve that eliminates the need for disassembly and cleaning of the needle valve, extends the lifespan of its parts, and reduces the frequency of part replacement. [Means for solving the problem]

[0010] The invention of claim 1 is a needle valve characterized in that a conical needle is attached to the tip end of a valve stem constituting a needle valve, a rotating handle is attached to the proximal end of the valve stem, a male thread is formed on the outer circumference of the proximal end of the valve stem, the male thread is screwed into a female thread formed in a small diameter hole in the boss portion of the housing, a cylindrical casing through which the valve stem is inserted is fixed to the housing, a female thread for attachment to a gas distribution branch pipe is formed in the housing, and one or more sealing materials are disposed between the outer circumference of the valve stem that does not have a male thread and the inner circumference of the hollow hole of the cylindrical casing.

[0011] The invention of claim 2 is a needle valve characterized in that, in the invention of claim 1, a sealing material is disposed between the hand-side end face of the cylindrical casing and the housing.

[0012] The invention of claim 3 is a needle valve characterized in that, in the invention of claim 1 or 2, a sealing material is provided at the mounting portion between the gas distribution branch pipe and the housing.

[0013] The invention of claim 4 is a needle valve characterized in that, in the invention of claim 1 or 2, the outer circumferential surface of the valve stem that does not have male threads is coated with a low-friction material resin. [Effects of the Invention]

[0014] According to this invention, cleaning of the spindle valve becomes unnecessary, the lifespan of the parts is extended, and the frequency of part replacement can be reduced. [Brief explanation of the drawing]

[0015] [Figure 1] This is a longitudinal cross-section of a needle valve. [Figure 2] This is an outline drawing of a valve stem. [Figure 3] This is a cross-sectional view of the cylindrical casing. [Figure 4] This is a cross-section of the housing. [Figure 5] This is a longitudinal cross-sectional view of a conventional needle valve. [Modes for carrying out the invention]

[0016] The embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following description, and various modifications and changes can be made by those skilled in the art based on the gist of the invention as described in the claims for utility model registration or disclosed in the forms for carrying out the invention. Such modifications and changes are also included within the scope of the present invention.

[0017] Figure 1 is a longitudinal cross-sectional view of the needle valve 1 of the present invention. The valve seat opposite the valve body needle 2 and the gas distribution branch pipe to which the housing 3 is attached are omitted from the description. The external shape of the valve body needle 2 is formed as a substantially cone shape. A boss portion 3 is provided on the base side of the cone, and a female thread 5 for attachment to the valve stem 4 is formed in the center of the boss portion 3. The needle 2 blocks the flow of fuel gas when in contact with the valve seat, and is made of a heat-resistant resin such as phenol that is resistant to oxidation and rusting in order to ensure good contact with the valve seat. In addition, a space is formed between the outer circumference of the cone and the boss portion 3, so that the needle 2 can undergo slight elastic deformation when pressed against the valve seat, thereby ensuring good contact between the needle 2 and the valve seat. The needle 2 is attached to the valve stem 4 by screwing the female thread 5 of the needle 2 onto the male thread 7 formed on the tip of the valve stem 4 via a lock nut 6.

[0018] As shown in Figure 2, a male thread 7 is formed on the tip side of the valve stem 4, and a male thread 8 is also formed on the outer circumferential surface of the handle side. Furthermore, a roughly rectangular prism-shaped handle mounting portion 9 is formed at the end of the male thread 8 on the handle side, and an annular groove 12 is formed for attaching a retaining ring 11 to prevent the handle 10 from coming off. In addition, the outer circumferential surface of the valve stem 4 where the male threads 7 and 8 are not formed is coated with Teflon®, a low-friction resin material. This makes it difficult for dust and other debris to adhere to the surface of the valve stem 4, and reduces the sliding resistance between the valve stem 4 and the O-ring 13, which is a sealing material.

[0019] As shown in Fig. 3, the cylindrical casing 14 has a hollow hole 15 formed at its center for inserting the valve rod 4. A plurality of annular grooves 16 are formed near the tip side of the hollow hole 15 for disposing the O-ring 13. This O-ring 13 functions as a sealing material for ensuring airtightness between the outer peripheral surface of the valve rod 4 and the inner peripheral surface of the hollow hole 15 when the valve rod 4 is inserted into the hollow hole 15.

[0020] On the near side of the cylindrical casing 14, a male thread 17 is formed for screwing and fixing the cylindrical casing 14 to the housing 3. Also, an annular groove 19 is formed on the near-side end surface of the cylindrical casing 14 for disposing an O-ring 18 to ensure airtightness with the housing surface.

[0021] As shown in Fig. 4, the housing 3 is composed of an annular lid body 20 for attaching and closing the housing 3 to the gas distribution branch pipe and a boss portion 21 formed at the near-side central portion. The lid body 20 is in a substantially circular dish shape, and a unified thread 22 for attaching to the gas distribution branch pipe is formed on the inner surface of the peripheral portion. A gasket 23 is disposed as a sealing material for ensuring airtightness with the gas distribution branch pipe on the surface corresponding to the bottom of the substantially circular dish shape. Parallel surfaces 24 are formed on two or four opposing surfaces on the outer surface of the boss portion 21 for convenience when attaching the lid body 20 to the gas distribution branch pipe.

[0022] In the inner diameter portion of the boss portion 21, a large-diameter hole is provided near the lid body 20 and a small-diameter hole is provided near the near side. A female thread 25 for screwing and fixing the cylindrical casing 14 is formed in the large-diameter hole, and a female thread 26 for screwing with the male thread 8 of the valve rod 4 is formed in the small-diameter hole, respectively.

[0023] After assembling the respective components constituting the needle valve 1 described above in the state shown in Fig. 1, the unified thread 22 of the housing 3 is screwed into the gas distribution branch pipe.

[0024] The flow rate of the needle valve 1 can be adjusted by operating a rotary handle 10 attached to the handle end of the valve stem 4. For example, when the rotary handle 10 is turned clockwise, the valve stem 4 moves toward the tip end, as the female thread 26 of the housing 20 and the male thread 8 of the valve stem 4 are right-hand threads, allowing the needle valve to close. On the other hand, when the rotary handle 10 is turned counterclockwise, the valve stem 4 moves toward the handle end, allowing the needle valve to open. In this way, the required gas flow rate can be easily adjusted by appropriately moving the valve stem 4 toward the tip end or the handle end. [Industrial applicability]

[0025] The needle valve according to this invention can be used as a needle valve installed in the fuel gas supply channel of a coke oven installed in a steel mill. [Explanation of Symbols]

[0026] 1. Needle valve 2 Needles (valve bodies) 3 Housing 4 valve stems 13. Sealing material (O-ring) 14. Cylindrical casing 18. Sealing material (O-ring)

Claims

1. A conical needle is attached to the tip of the valve stem that makes up the needle valve. A rotating handle is attached to the handle end of the valve stem. A male thread is formed on the outer surface of the valve stem near the proximal end. The male thread engages with the female thread formed in the small-diameter hole of the boss portion of the housing. A cylindrical casing through which the valve stem is inserted is fixed to the housing. The housing has a female thread formed for attachment to a gas distribution branch pipe. A needle valve characterized in that one or more sealing materials are disposed between the outer surface of the valve stem that does not have male threads and the inner surface of the hollow hole in the cylindrical casing.

2. The needle valve according to claim 1, characterized in that a sealing material is disposed between the proximal end face of the cylindrical casing and the housing.

3. The needle valve according to claim 1 or 2, characterized in that a sealing material is provided at the mounting portion between the gas distribution branch pipe and the housing.

4. The needle valve according to claim 1 or 2, characterized in that the outer surface of the valve stem that does not have male threads is coated with a low-friction material resin.

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