JP2013044376A - Packing material, packing intermediate, packing and manufacturing method for the packing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packing material that exerts excellent sealability for a long period of time even under the high temperature, is excellent in workability when incorporated or when removed, and can be manufactured by simple processes, and to provide a packing.SOLUTION: The packing material is formed by winding a mica tape on a metal wire. A packing intermediate is formed by braiding the packing material. The packing is obtained by pressing the packing intermediate after baking it.

Description

  The present invention relates to a packing material, a packing intermediate, a packing, and a method for manufacturing the same, particularly as a sealing material for a flame propagation tube of a gas turbine combustor for thermal power generation.

  A general gas turbine combustor for thermal power generation includes a plurality of gas turbine combustors, each of which is configured to react fuel and compressed air to generate high-temperature and high-pressure combustion gas. ing.

  All the adjacent gas turbine combustors are connected by a connecting pipe (flame propagation tube outer cylinder), and a flame propagation tube is installed inside the connection pipe. The flame propagation tube has a tubular shape, and the combustion gas passes through the flame propagation tube due to a pressure difference between the connected gas turbine combustors. Therefore, a material that can withstand long-term use at a high temperature of 450 ° C. or higher is required for the flame propagation tube packing.

  Conventionally, asbestos packing based on asbestos has been used as this flame propagation tube packing, but asbestos is prohibited, and as an alternative, expanded graphite as a base material or mica as a base material. Various things have been proposed.

  When the expanded graphite base material is used for a flame propagation tube for a long period of time, such as six months to two years, the expanded graphite of the base material will be oxidized and lost due to heat, and the sealing performance will not be maintained. There is. Further, expanded graphite that suppresses the disappearance of oxidation and a combination of aluminum foil and expanded graphite have been used, but the long-term sealing performance is still unsatisfactory.

  Japanese Patent Laid-Open No. 2002-340187 discloses a packing in which a main seal packing formed by rolling mica sheets and press-molded into a ring shape is combined with a mesh spring formed into a ring shape after braiding a thin metal wire. Yes. Japanese Patent Laid-Open No. 5-118444 discloses a packing in which a strip-like mica material is filled in a cylindrical body formed of fibers, and the mica material has a fiber as a reinforcing material interposed between the sheet layers. A material is disclosed. All of these packing materials and packings are excellent in heat resistance and oxidation resistance at high temperatures, and excellent sealing characteristics can be ensured over a long period of use even under high temperature conditions.

Japanese Patent Laid-Open No. 2002-340187 Japanese Patent Laid-Open No. 5-118444

  However, the packing disclosed in Japanese Patent Application Laid-Open No. 2002-340187 is not satisfactory because the number of parts is plural and workability at the time of incorporation and removal is poor. Further, the packing material and packing disclosed in Japanese Patent Application Laid-Open No. 5-118444 have many manufacturing processes, and there is a problem that an increase in manufacturing cost is unavoidable.

  Accordingly, an object of the present invention is to provide a packing material, a packing intermediate, and a packing which can be manufactured in a simple process while exhibiting good sealing performance for a long period of time even at high temperatures, and having good workability at the time of incorporation and removal. And a manufacturing method thereof.

  In such a situation, the present inventor has conducted intensive studies, and as a result, used a packing material in which a mica tape containing a reinforcing material is wrapped with a metal wire if necessary, and heated an intermediate body braided with the packing material. It has been found that if the packing is processed and pressure molded in particular, it exhibits good sealing performance for a long period of time even at high temperatures, and it has good workability during installation and removal, and can be manufactured in a simple process. The present invention has been completed.

  That is, the present invention provides a packing material formed by winding mica tape with a metal wire.

  The present invention also provides a packing intermediate formed by braiding the packing material.

  Moreover, this invention provides the packing which braids the said packing material, Comprising: Under atmospheric pressure, the heating loss of 500 degreeC is 10% or less.

  In addition, the present invention is obtained in Step I for obtaining a packing material by winding a metal wire around mica tape, Step II for obtaining a packing intermediate by braiding the packing material obtained in Step I, and Step II. The packing manufacturing method which performs the III process which heat-processes the packing intermediate body.

  According to the packing of the present invention, good sealing performance is exhibited over a long period of time even at a high temperature, and workability at the time of incorporation and removal is good and can be manufactured by a simple process.

It is a figure explaining the winding state of the metal wire in the packing material of this invention. It is a figure explaining the other winding state of the metal wire in the packing material of this invention. It is a figure explaining the other winding state of the metal wire in the packing material of this invention. It is a figure explaining the other winding state of the metal wire in the packing material of this invention. It is a high temperature seal test result of Example 1 and Comparative Example 2.

(Description of packing material)
The mica tape used in the packing material of the present invention is obtained by cutting a mica sheet into a tape shape. The width dimension is preferably 1 mm to 10 mm, particularly preferably 2 mm to 8 mm, more preferably 3 to 5 mm. There are also lengths of up to several tens of meters. When the width dimension of the mica tape is in the above range, the braiding is easy. A commercially available mica tape may be used.

  The mica sheet is obtained by peeling off mica ore produced as ore into a flake form with high-pressure water such as a water jet, and using a binder such as rubber or a silicon-based adhesive. Therefore, the mica tape used in the packing material of the present invention includes a binder such as rubber, a silicon-based adhesive, and the like. Examples of mica include hard mica and soft mica. Among these, soft mica (Phlogopite) is preferable in that it has a high crystal water decomposition temperature and excellent heat resistance.

  It is preferable that a binder such as a silicon-based adhesive is included at a maximum of 16% by weight in the packing material. By including a binder such as rubber or silicon-based adhesive in the packing material within the above range, mica that is easily peeled can be stably held in a sheet shape.

  Examples of the metal wire used in the packing material of the present invention include stainless steel wires such as SUS304, SUS316L, and SUS316. Among these, SUS304 and SUS316L are preferable in terms of heat resistance, corrosion resistance, workability, and availability. The wire diameter of the metal wire is preferably 0.02 mm to 0.2 mm, particularly preferably 0.077 mm to 0.083 mm. If the wire diameter of the metal wire is within the above range, it is easy to wind the metal wire around the mica tape, and it is possible to effectively prevent the mica from protruding when the packing is tightened.

  The mica tape used in the packing material of the present invention preferably contains a reinforcing material. Examples of the reinforcing material include metal wires, inorganic fibers, and organic fibers. Examples of the metal wire include the same metal wires as those described above. Examples of inorganic fibers include ceramic fibers, glass fibers, and carbon fibers. Examples of organic fibers include aramid fibers and rayon fibers. The reinforcing material increases the mechanical strength of the mica tape, and the mica tape reinforced with the reinforcing material can maintain its shape when winding the metal wire, and also depends on the load at the time of tightening the packing. The protrusion of mica can be prevented in cooperation with the wound metal wire. The reinforcement is present inside the mica tape, and even if it exists uniformly in the thickness direction of the mica tape, it exists in a specific location such as an intermediate portion in the thickness direction of the mica tape. There may be. Preferred reinforcing materials are metal wires and inorganic fibers. If the reinforcing material is a metal wire and inorganic fiber, it will not disappear even if the baking process is performed in the packing manufacturing process.

  The example of the winding in this invention is demonstrated with reference to FIGS. 1-4 is a figure which shows the one part surface in the longitudinal direction of the packing material 10, and is actually a tape shape further extended in a longitudinal direction. Reference numeral 1 is a mica tape, and 2 is a metal wire. In the present invention, winding means the same as winding. For example, the mica tape surface has a mesh-like winding (FIG. 1), a lattice-like winding (FIG. 2), a substantially rectangular or substantially trapezoidal gap. Winding (FIG. 3) in which is formed, winding (FIG. 4) in which an irregularly shaped gap is formed, and the like. The number of metal wires wound around the mica tape is not particularly limited, but may be appropriately used within a range of, for example, 4 to 20. Metal wire wrapping refers to a state in which the metal wire is wound so as to be substantially in close contact with the surface of the mica tape, and winding in which most of the metal wire is separated from the surface of the mica tape is excluded. The By winding the metal wire so as to substantially adhere to the surface of the mica tape, it is possible to effectively prevent the mica from protruding when the packing is tightened.

  Further, the density of the metal wire on the surface of the mica tape is not particularly limited, but in the case of winding with a regular mesh shape as shown in FIG. 1, the interval between adjacent metal wires is about 1 to 3 mm. preferable. In the present invention, the winding of the metal wire may be a complete coating with no gap area surrounded by the metal wire, but the effect of preventing the protrusion when the packing is tightened is not improved so much. This is not preferable. Compared with a packing material in which a cylindrical body formed of a conventional metal wire is filled with a plurality of strip-shaped mica materials, the packing material of the present invention is obtained by winding a metal wire around one mica tape. Therefore, the variation of the dimension after braiding can be taken widely.

(Description of packing material manufacturing method)
In the present invention, examples of the method for producing the packing material include a method having a step of cutting a mica sheet into a tape shape and a step of winding a metal wire around the cut mica tape. The step of cutting the mica sheet into a tape shape is as described for the packing material.

  The step of winding the metal wire around the cut mica tape includes, for example, a mica tape unwinding body on which the mica tape is wound, and 4 to 20 on which the metal wire arranged around the mica tape unwinding body is wound. A lower apparatus composed of a group of hobbins, an upper apparatus that is a drum-shaped winding body for winding a mica tape wound with a metal wire above the lower apparatus, and a position between the upper apparatus and the lower apparatus. A device provided with a base through which a mica tape wound with a metal wire to be wound can be used. The mica tape of the unwinding body and the tip of the metal wire wound around the hobbin are put together, pass through the base, and are fixed to the winding body. Further, the hobbin moves in a certain plane in the winding process. Accordingly, the mica tape is moved upward by rotating the winding body of the upper apparatus, and the metal wire is wound around the mica tape in a mesh shape while rotating. In addition, since the tape shape of the mica tape wound with the metal wire passes through a die having substantially the same shape as the cross-sectional shape of the mica tape, it is substantially the same as the tape shape before the metal wire is wound. As a method of blending a reinforcing material in the packing material, a method described in JP-A-5-118444 may be followed.

(Description of packing intermediate and its manufacturing method)
In the present invention, the packing intermediate is formed by braiding the packing material. The packing material to be braided may be cut in advance to a desired length before braiding. A plurality of mica tapes wound with a packing material, that is, a metal wire are usually used by a braiding method. The braiding method may be any braiding method such as bag knitting, lattice knitting, eight knitting, etc., depending on the intended use and packing thickness. The knitting such as bag knitting, lattice knitting, and eight knitting may be performed in accordance with a known knitting method. The packing intermediate is a braided mica tape wound with a metal wire, and contains a binder and a reinforcing material that is an optional component. Such a packing intermediate body becomes a packing of the present invention by obtaining a predetermined processing step described later. Moreover, such a packing intermediate body can also be used as a packing as it is depending on a use application.

(Description of packing)
The packing according to the first embodiment of the present invention is formed by braiding the packing material, and the heating loss at 500 ° C. under atmospheric pressure is 10% or less, preferably 8% or less. If the heating loss at 500 ° C is within the above range under atmospheric pressure, there will be a gap inside the packing because there is almost no heating loss even when used at high temperatures like packing for flame propagation tubes. And a stable and good seal can be maintained. When the heating loss at 500 ° C. is outside the above range under atmospheric pressure, when used at a high temperature as in the flame propagation tube packing, a gap due to the heating loss is generated in the packing, and the sealing performance is lowered.

  The packing according to the second embodiment of the present invention further contains 5 to 10% by weight, preferably 4 to 8% by weight, of boron nitride. By containing boron nitride, the high-temperature heat resistance is further improved and the sliding characteristics are improved. For this reason, it becomes a more suitable thing as packing for flame propagation pipes.

  The packing according to the third embodiment of the present invention is obtained by pressure-molding the packing according to the first embodiment into a ring shape. The packing in the third embodiment is made of braided mica tape wound with a metal wire, and is further press-molded, so that the ring shape does not collapse and is easy to assemble and long. Can be easily removed after assembly for a period. Further, although the packing according to the third embodiment does not contain boron nitride, mica is the main material, so that it has sufficient heat resistance as a flame propagation tube packing.

  The packing according to the fourth embodiment of the present invention is obtained by pressure-molding the packing according to the second embodiment into a ring shape. The packing according to the fourth embodiment has the same effects as the packing according to the third embodiment, and also contains boron nitride, so that it has outstanding heat resistance and is particularly suitable as a flame propagation tube packing. It will be a thing.

  Any of the packings in the first to fourth embodiments of the present invention may contain other fillers such as scaly graphite and surfactant. Another filler can be used individually by 1 type or in combination of 2 or more types. These other fillers improve the familiarity with the piping and impart sliding characteristics to the packing.

(Method for manufacturing packing)
The packing manufacturing method according to the first embodiment of the present invention includes an I step of obtaining a packing material by winding mica tape with a metal wire, and a packing intermediate obtained by braiding the packing material obtained in the I step. II process which obtains and III process which heat-processes the packing intermediate body obtained at this II process. Steps I and II are the same as the method for producing the packing intermediate. In step III, the packing intermediate is heated. Examples of the heat treatment conditions include a method of baking at atmospheric pressure at a temperature of 300 ° C. or higher, preferably 500 ° C. or higher, for 8 hours or longer, preferably 10 hours or longer. By the heat treatment, organic components such as a binder present in the packing intermediate can be eliminated, and the packing (product) can be reduced to 10% or less at 500 ° C. under atmospheric pressure. Further, the disappearance of the organic component creates a gap in the packing, which facilitates impregnation with boron nitride described later. Moreover, the space | gap which arose in packing by the loss | disappearance of an organic component can be eliminated by pressure molding. It should be noted that other fillers such as scaly graphite and surfactant can be impregnated after this heat treatment and blended into the packing.

  In the packing according to the second embodiment, in addition to the I step, the II step, and the III step, the packing obtained in the III step is further impregnated with a lubricant containing boron nitride. can get. The lubricant used in the IV process is a liquid lubricant used for impregnating packing with boron nitride. Such liquid lubricants include mineral oils or synthetic lubricants. Further, the amount and treatment amount of boron nitride in the lubricant are such that after the impregnation treatment, the amount of boron nitride in the packing is 5 to 10% by weight, preferably 4 to 8% by weight. do it. The impregnation treatment may be performed by a known method. After the impregnation treatment, it is dried to remove excess lubricant and the like. According to the packing in the second embodiment, in addition to the same effects as the packing in the first embodiment, the familiarity with the piping and the sliding characteristics of the packing are improved.

  The packing in the third embodiment can be obtained by performing a V step for pressure forming the packing obtained in the step III in addition to the steps I, II and III. The pressure forming may be performed by a known pressure forming process such as a ring shape. By pressure molding, voids in the packing produced in the step III can be eliminated, and good sealing properties can be imparted.

  The packing in the fourth embodiment can be obtained by performing a V process for pressure forming the packing obtained in the IV process in addition to the I process, the II process, the III process, and the IV process. The pressure molding is the same as the pressure molding in the packing manufacturing method according to the third embodiment. The packing according to the fourth embodiment has the same effects as the packing according to the third embodiment, and improves the familiarity with the piping and the sliding characteristics of the packing.

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.

(Production of packing material)
A mica sheet having a thickness of 0.4 mm was obtained by peeling off the raw mica from high-pressure water such as a water jet into a flake shape using a silicon-based adhesive. This mica sheet was cut into a tape having a width of 4 mm to obtain a mica tape. Next, a SUS316L metal wire having a wire diameter of 0.08 mm is prepared, and 16 metal wires are wound around one mica tape so as to form a mesh as shown in FIG. Obtained. The gap between adjacent metal wires was about 2 mm. 53 such packing materials were produced.

(Production of packing intermediate)
The 53 packing materials thus obtained were knitted into a bag to obtain a bag-shaped packing intermediate. The bag-like packing intermediate had a nominal diameter of 12.5 mm.

(Production of packing)
The bag-like packing intermediate was baked for 16 hours at a temperature of 400 ° C. under atmospheric pressure. By this baking, the silicon-based adhesive present in the packing intermediate was lost. Next, an air-baked packing was immersed in a dispersion obtained by dispersing boron nitride, graphite or the like in a mineral oil-based lubricating oil and impregnated. The immersion conditions were room temperature and 3 minutes. The boron nitride content in the packing was 4.3% by weight. Then, it dried at room temperature for 15 hours or more. Next, a bag-impregnated packing impregnated with boron nitride was press-formed in a ring shape. The obtained ring packing was subjected to the following heat loss test, high temperature sealing test, HTS (Heat Transfer Salt) immersion test, actual machine test I, and actual machine test II. The results of the heat loss test are shown in Table 1, the high temperature sealability test results are shown in FIG. 5 together with the relationship diagram of the heating temperature and the heating time, and the HTS immersion test is shown in Table 2.

  As is apparent from FIG. 5, the packing of Example 1 showed a sealing performance equal to or higher than that of the high temperature asbestos packing. In particular, the packing of Example 1 tended to be more stable in sealing performance than the high-temperature asbestos packing after two cycles after the heat was once applied.

(Heating loss test)
The heating loss at the following heating temperature and heating time was measured. The loss on heating was determined by (initial weight−weight after heating) × 100 / initial weight.
Heating temperature: 400 ° C, 600 ° C, 800 ° C
・ Heating time: 22 hours, 46 hours, 168 hours

(High temperature sealability test)
Using a simulated valve test device, the amount of leakage was measured for a predetermined time under the following conditions.
Sample size: inner diameter 20 × outer diameter 30 × height 30
・ Heating temperature: 400 ℃
-Heating time: 16 hours x 3 cycles-Test gas: Nitrogen gas, 1.96 MPa
・ Tightening surface pressure: 49MPa

(HTS immersion test)
The sample was immersed in 470 ° C. HTS (NaNO ₃ 40%, KNO ₃ 7%, NaNO ₂ 53%) fluid, and the weight loss rate (%) after 24 hours, 50 hours, and 100 hours was determined.

(Real machine test I)
It was used as a seal material for the flame propagation tube of the gas turbine combustor of company X thermal power plant No. 3 series, and the durability test was conducted under the following conditions. As a result, at the present time after 18 months, no leakage has been caused. Also, it was very easy to attach the ring gasket to the seal portion.
・ Sample size: Inner diameter 108.5 × Outer diameter 126.9 × Height 19.8 × 2 Ring ・ Fluid: Compressed air with maximum temperature 470 ° C. and pressure 1-1.5 MPa ・ Test time; Until it is done Note that 2 rings means that 2 sheets are used.

(Real machine test II)
It was used as a sealing material for the concentrated nitric acid production line of Company Y, and a durability test was conducted under the following conditions. As a result, at the end of 15 months, no leaking has occurred yet. Also, it was very easy to attach the ring gasket to the seal portion.
・ Sample size: Inner diameter 24 × Outer diameter 37 × Height 19.5 × 3 ring ・ Fluid: HTS fluid at a temperature of 450 ° C. and a pressure of 0.5 MPa ・ Test time; Until a problematic leak occurs Means that three sheets are used.

Comparative Example 1
(Preparation of sealing material mainly composed of expanded graphite)
An expanded graphite mold packing was produced by compression-molding an expanded graphite tape with a mold. The heat loss test was performed on the expanded graphite mold packing. The results are shown in Table 1.

  As is apparent from Table 1, even when exposed to a high temperature (800 ° C.) oxidizing atmosphere where the expanded graphite mold packing completely disappeared for a long time, the packing of Example 1 had very little loss on heating. .

Comparative Example 2
A commercially available asbestos packing for high temperature was used. About the asbestos packing for high temperature, the said HTS immersion test and high temperature seal property test were done. The results are shown in Table 2 and FIG.

Comparative Example 3
An expanded graphite braided packing was produced in which a reinforcing tape in which a SUS304 metal wire having a wire diameter of 0.2 mm was arranged at the central portion in the thickness direction of the expanded graphite tape was bag knitted. The expanded graphite braided packing was subjected to the above HTS immersion test. The results are shown in Table 2.

  As is clear from Table 2, the expanded graphite braided packing has a significant weight reduction. Moreover, the packing of Example 1 has a smaller weight loss than the high temperature asbestos packing.

  As described above, the packing of the present invention is heat resistant (oxidizing atmosphere), sealing performance at less than 400 ° C. (oxidizing atmosphere), sealing performance at 400 ° C. or higher (oxidizing atmosphere), and mounting / removal operations. It was excellent. Moreover, it was able to manufacture by a relatively simple process. On the other hand, the packing in which the expanded graphite braided packing and the expanded graphite mold packing were combined was fragile to be removed even in the test, and it took time for cleaning. Moreover, it was inferior in heat resistance and sealing performance (oxidizing atmosphere) at 400 ° C. or higher.

The packing of the present invention is suitable as a gland packing for a flame propagation pipe of a gas turbine combustor for thermal power generation, an exhaust pipe of an automobile, and an HTS (Heat Transfer Salt). HTS is a nitrate used in a heat medium for high temperature and refers to a mixture of NaNO ₃ / KNO ₃ / NaNO ₂ . The packing of the present invention exhibits excellent sealing properties over a long period of time under conditions of a maximum use temperature of 800 ° C. and a maximum use pressure of 2 MPa.

1 Mica tape 2 Metal wire 10 Packing material

Claims (12)

  Packing material characterized by winding mica tape with metal wire.   The packing material according to claim 1, wherein the winding is wound in a mesh shape.   The packing material according to claim 1, wherein the mica tape is reinforced with a reinforcing material.   The packing material according to any one of claims 1 to 3, wherein the metal wire has a wire diameter of 0.077 to 0.083 mm.   The packing intermediate body formed by braiding the packing material of any one of Claims 1-4.   A packing comprising the packing material according to any one of claims 1 to 4, wherein the heating loss at 500 ° C under atmospheric pressure is 10% or less.   The packing according to claim 6, wherein boron nitride is contained in the packing in an amount of 5 to 15% by weight.   The packing according to claim 6 or 7, wherein the packing is pressure-formed in a ring shape. I process of obtaining packing material by winding mica tape with metal wire,
Step II for braiding the packing material obtained in Step I to obtain a packing intermediate;
A packing manufacturing method, comprising: a step III of heat-treating the packing intermediate obtained in the step II.   The packing manufacturing method according to claim 9, wherein an IV step of impregnating the packing obtained in the step III with a lubricant containing boron nitride is performed.   The packing manufacturing method according to claim 9, wherein step V is performed to press-mold the packing obtained in step III.   The packing manufacturing method according to claim 10, wherein a V step of forming the packing obtained in the IV step is performed.

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