JPS5828082A - Sealing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A valve using the stem seal device of the present invention is a high-pressure, high-temperature, twin-up stem gate valve that is similar to the invention disclosed in the following U.S. patent application. be. No. 833.684, filed by David B. Heard on September 15, 1977, "A temperature-resistant, chemically "Stable High Pressure Gate Valve" and Charles ° on June 16, 1976
・Patent No. 697゜0 filed by Dee Moriμ
No. 84, ``High-temperature single-face pressure with a solid lubricating metal mutual stem seal loaded in advance in a laminated form under a high load,
Balanced rising stem gate valve.

The stem seal device of this invention is disclosed in the above-mentioned US Pat. No. 697
, 084+L.

Said applications are assigned to the assignee of this invention and their disclosures are incorporated into the art of this invention by reference.

In the petroleum and ganu industries, pressure and temperature gradually increase as the hole gets deeper during drilling, and in sour ganu fields, the fluid flowing out of the well contains a relatively high proportion of hydrogen sulfide (H2S).

Valves and Wellhead River seals have recently been developed for use in oil fields, but these seals are under high pressure.

Relatively little deterioration due to high temperature interaction, and H2
It is also relatively resistant to corrosive fluids such as S.

Morrill Patent No. 4, registered on November 1, 1977.
No. 056.272, which is filed by the same applicant as Application No. 697,084, is owned by the right holder of this invention, but its disclosure content is also adopted in this invention. That is, a static seal between the well head and the pipe hanger. This seal consists of a pair of conical metal ring gaskets, the cross-section of which is approximately rectangular. The metal ring gasket is compressed by a locking screw and a compression ring, and the ends of the gasket are plastically deformed and engage the parallel cylindrical walls of the well head and pipe hanger to create a metal-to-metal seal. It is tightened until it stops. The initial cross-sectional shape of the deformable ring used in such static seals is trapezoidal, made of Teflon, poly.

Made of urethane, rubber, etc. The ring is disposed between the metal ring gaskets and presses against the metal ring gaskets to make the ring cross-sectionally rectangular and engageably flush with the walls of the well head and pipe hanger. The deformable ring used in this static seal can be used in situations where the seal provided by the metal ring gasket is incomplete, such as when there are scratches or mechanical marks on the well head or pipe hanger.
This metal ring acts as a backup seal for the gasket. This deformable ring penetrates and seals these scratches and mechanical marks.

The seal used for dynamic or static sealing between the valve stem and the valve body or bonnet is a stretchable truncated metal ring gasket with a rectangular cross-sectional shape. This metal ring gasket is disposed within a packing box provided around the stem, and a ring made of a material that is easily deformed in one direction is sandwiched therebetween. Although the metal ring gasket is made of a soft material rather than spring copper, it has elastic properties similar to Belleville springs for two reasons. First, when the gasket is not pressed, the inner diameter of the gasket should be made larger and the outer diameter smaller, so that the seal unit can be moved against the valve stem and the packing box without causing excessive friction with the packing box. This is to allow easy attachment and detachment. Second, when the valve is used, when the temperature and pressure change, the deformation and distortion of the gasket that initially occurred when the packing retainer was tightened will change slightly, and even if the dimensions of the valve pad change slightly, this gasket will This is to maintain compression integrity between the stem and the packing box. In other words,
This gasket must be elastic to maintain the pre-applied load.

The above-mentioned valve stem sea p is disclosed in the above-mentioned Application No. 69 Otsu 0848.
It is disclosed in the ACME paper "Seals for valve stems and well heads that can be used under high pressure and high flow conditions" by Oyohi, T. Morip, C., and Mayer C.W.

The latter was prepared for presentation at an academic conference held in Mexico City, Mexico, from September 19th to 24th, 1976, and its contents are also used in this invention. A threaded packing retainer is fastened to the seal disclosed in this invention to press and flatten the metal ring gasket. In this case, the inner and outer edges of the metal ring gasket are deformed and come into contact with the outer surface of the gasket and the wall surface of the packing box, thereby creating a metal-to-metal seal.

The clamping ring sandwiched between the metal ring gaskets is also deformed by being compressed against the seal and is engaged with the stem and packing box according to the shape of the metal ring gaskets. The ring sandwiched between the metal ring gaskets must have some degree of elasticity. Upon initial deformation, the clamping ring is usually set in place, while retaining some elasticity. The material forming the clamping ring in such a seal is a fluororesin, such as tetrafluoroethylene polymer or gutsphite. Such materials also include tetrafluoroethylene polymers containing up to about 15% molybdenum disulfide.

The clamping ring used for the valve stem seal is a dynamic seal, and has the function of dynamically sealing between the metal ring gasket and the stem when the metal ring gasket becomes malfunctioning due to the sliding movement of the stem. be.

Such a clamping ring also tends to wear due to contact with the stem and to slide over the contact area of the stem and metal ring gasket, reducing the friction between the stem and the metal ring gasket. The pinch ring further provides lubrication between the stem and the pinch ring and between the pinch ring and the metal ring gasket to reduce friction. The pinch ring also acts as a backup seal for the metal ring gasket. This is described in US Pat. No. 4.
This is similar to the deformable ring back-up seal for sealing between the well head and pipe hanger in No. 056.272, which penetrates and seals scratches and mechanical marks on the stem.

The present invention relates to an improvement of the above-mentioned valve stem seal.

The stem seal according to No. nII has five metal ring gaskets with two clamping rings arranged between them. This is known as an SMT type seal. This S M T type seal has an operating pressure of up to 25,0
001) Si (1,750"cΔ), usage temperature -20
It is constructed to provide sufficient stem sealing for valves between .degree. F. and 600.degree. F. (-29 DEG -149 DEG C.).

However, if the operating pressure is 30.000 p81 (
For valves of 2,100 kti/cs or more,
SMT type seals cannot always provide sufficient pulp stem sealing. For example, a material consisting only of graphite has an operating pressure of 30.0001)Si(2,1
It is not suitable for SMT type stem seals for 00kti/ca) class valves. This is because the graphite material tends to be pushed past the metal ring gasket when the gasket is pressed flat to seal. This is because the graphite is forced out before the gasket is flat enough to seal between the pulp stem and the packing box. Additionally, graphite tends to be worn away and eroded by valve stem operation, as graphite is deposited on the stem and carried by the stem across the gasket and out of the packing box. be. Operating method: 30,000psi (2,1
00k<//cyl), the graphite is extruded or worn for the reasons mentioned above, and fluid leaks from the sealing portion, making it necessary to replace the graphite clamping ring.

Similarly, materials made only of tetrafluoroethylene polymer (TFE),
Alternatively, a material made by adding MnS2 to tetrafluoroethylene polymer has an operating pressure of 30,000 psi (2,I DOk
It is not suitable for SMT type stem seals of valves used at high pressures such as M'). This is because such materials cannot maintain a constant hermetic seal against such high pressures when the valve is subjected to temperature cycling. Valves used in oil fields are filled with high-pressure fluid from deep wells.
0°F (149°C). When the flow of fluid through the valve is stopped, such as by closing a well, the temperature of the valve is cooled to room temperature, or about 70°F (21°C). When the well is reopened, fluid begins to flow again and the valve temperature rises again to 300°F' (149°C). Thus, the valve temperature ranges from about 70°F to about 60°F.
Varies between 0°F (21-149°C). Within the temperature range at which the valve will be used, the valve stem seal must be able to maintain a tight seal at all times and no matter how temperature cycled. T
F'E! TFE added with 100% or MnS2! SMT type seal using J-ring is approximately 30.0OOI)Si
At an operating pressure of (2,100 kLJ/d), approximately 70
Room temperature of °F (21 °C) and 300 °r ('149 °C)
However, when a humidity cycle is applied to the valve, such as raising the temperature from room temperature to 600°l' (149°C) and then returning it to room temperature, the SMT type seal has no constant resistance. Unable to maintain confidentiality. In addition, a small amount of leakage may occur from the seal portion when the valve stem is in operation or at rest. Retightening the packing retainer will stop the leak, but temperature cycling will cause it to leak again.

The purpose of this invention is to operate at an operating pressure of 30,000 psi (
-20°F to 300°F' (-29 to 14
The object of the present invention is to solve the above problem by providing a reliable valve stem seal suitable for temperature cycling in the temperature range (9° C.). Another object of this invention is to provide 30,000 pSi (2,100
kg/c (71 kg/c) or higher, or when the valve is heated from room temperature to approximately 600°F (
The object of the present invention is to provide a seal that is airtight and leakproof without having to retighten the packing retainer when a temperature cycle such as returning to room temperature (149° C.) is further applied. Still another object of this invention is to provide simple and compact design.

To provide a sea μ that is inexpensive and easy to manufacture, install, and handle. Yet another object of the invention is to provide a seal that is highly wear resistant, durable, relatively resistant to degradation due to high temperatures, temperatures and pressures, and chemically stable to the fluids to which it is applied. There is a particular thing.

The high pressure, two-way rising stem gate valve of this invention is
between the bonnet of the pulp body and the operating stem of the valve;
The seal μ between the chamber of the loop body and the balance stem is a metal mutual stem sealing device using a stretchable material. Each sealing device has at least one seal set consisting of a pair of frustoconical, stretchable metal ring gaskets, with a highly lubricating material such as tetrafluoroethylene polymer between each metal ring gasket. Two assembly rings made of a durable stretchable material are arranged, one assembly ring contacting one metal ring gasket and the other assembly ring contacting another metal ring gasket. .

A core ring is arranged between these two assembly rings. The coefficient of body expansion of any core ring due to heating is smaller than the coefficient of expansion of an assembled ring made of dense gutsphite or the like. The inner diameter of the core ring is larger than the inner diameter of the assembly ring.

A bearing ring is disposed along the inner circumference of the core ring between the core ring and the operating or balance stem of the valve.

The bearing ring is formed of the same type of material as the assembly ring, such as tetrafluoroethylene polymer. Each seal set is placed inside an annular box. This packing box is provided adjacent to the pulp body and extends around the stem. Each packing box is closed by an annular packing retainer threaded into its interior, pressing against a frustoconical metal ring gasket. Therefore, the inner and outer peripheral edges of each metal ring gasket engage with the stem and the packing box, respectively. In this case, sufficient pressure is applied to the concave inner circumferential edge and convex outer circumferential edge of the metal ring gasket, causing it to plastically deform. The clamping layer consisting of the core ring and the bearing ring cut between the assembly rings deforms and follows the shape of the space formed between the pressed metal ring gaskets, filling approximately the entire space. The volume of the core ring is approximately 1/3 of the volume of the entire sandwich layer. Even if the valve is activated and temperature cycles are applied, the packing retainer maintains its tightness and maintains the preloaded state without having to retighten it. The valve stem seal set of this invention is
It can also be used to completely back up the fixing screw, and even when subjected to temperature cycles, the movable part remains closed during and after operation.

Next, an embodiment of the present invention will be described with reference to the drawings. The valve shown in FIG. 1 has a hollow body to which a chamber 21 and a bonnet 23 are fixed by studs 25 and nuts 27. The space between the cell 21 and the cell 21 is sealed with an appropriate pressure-maintaining gasket 29. A pedestal slot 1, 63 installed at the inner end of the passage 35. The sealant is stored in a reservoir 43.45 and is connected to a passageway 47.49 for the distribution of sealant. Opening/closing game) 39.41 and pedestal 31
．． 33 interface and the neck of pedestal 31.33 (+-7 < loop body interface) to seal these interfaces.

The opening/closing game (39, 41) moves back and forth between the closed position and the open position by means of a cylindrical operating stem 51. The closed position is shown in FIG. 1, in which fluid cannot flow through passageway 35,37. On the other hand, in the open position the gate bow) 53.55 coincides with the boat 57.59 in the pedestal 31.33 and fluid flows through the passage 35.37.

The upper end of the operating stem 51 extends outwardly from the chamber 21 and passes through a port 61 formed in the bonnet 26. The sealing member 66 of the present invention seals between the operating stem 51 and a substantially cylindrical packing box 65 formed within the bonnet 26. This seal member 63 is a packing retainer 67
It is press-fitted into the packing box 65 by. This packing retainer 67 is screwed into a neck 69 formed in the upper part of the bonnet 23 and having a screw inside. After the operating stem 51 is seated rearward, the bleeder port 71
It is used to check for fluid leakage between the operating stem 51 and the port 61.

A screw is also cut on the outside of the neck 69 of the bonnet 23, and the bearing retainer 76 can be screwed into this screw.

An operating nut 75 is screwed into the threaded upper portion 77 of the operating stem 51 . This operating nut 75 is formed with a flange 79, on which Nulast bearings 81, 83 are coaxially disposed above and below. A null bearing 86 disposed below the flange 79 engages with the upper part of a washer 85 installed in the second part of the packing retainer 67. The Nulast bearing 81, which is disposed in the upper part of the flange 79, engages with the inside of the upper end of the bearing retainer 73. A non-circular hole 89 is formed in the handwheel/L' 87, and the non-circular hole 89 is aligned with a corresponding non-circular portion 91 formed in the operating nut 75. Hand hobby/1/8th eye 1, movement nut 7
5 and is held in place by a tenor nut 96. The breeder boat 95 has an operating stem 5
This is to allow fluid to escape from between the threaded upper part of No. 1 and the operating nut 75.

The balance stem 97 with a round shape opens and closes) 39
．． 41 and extends to the outside of the valve chamber 21 through a port 99. This balance stem 97 and
A substantially cylindrical packing box 106 formed inside the valve body
A sealing member 101 according to the present invention seals the space between the two. This sealing member 101 is press-fitted into the packing box by a packing retainer 105 provided below. This packing retainer 105 has a threaded socket 1 formed coaxially with the port 99 and the packing box 103.
It is screwed into 07. When the enlarged part of the upper end of the balance stem 97 is formed in the boat 990 of the valve body and is securely seated on the fc annular pedestal, fluid leakage between the balance stem 97 and the port 99 will be prevented. Checked by breeder boat 109. The valve body has
A cap 111 is fixed by a screw 113 and covers the lower end of the packing retainer 105, that is, the balance stem 97.

When the handwheel 1v87 is turned, the operating nut 75 is turned and the operating stem 51 is operated. When the operating stem 51 operates, the opening/closing gouges 39 and 41 connected to the operating stem 51 by the hub 115 move up and down. As the opening/closing gate 39.41 moves up and down, the balance stem 97 connected to the opening/closing gate 39.41 by the hub 117 moves up and down. The operating stem 51 and balance stem 97 therefore move in the axial direction relative to their respective sea 2 members 63, 101. In this case, the seal member 66
101 needs to be reliably held during the movement of each stem 51, 97 in the axial direction and before and after the movement.

Since the seal members 63 and 101 are the same, a detailed description of one of them will be omitted. Referring to FIGS. 2A and 2B, seal member 66 consists of an upper seal set 119 and a lower seal set 121. The lower matching ring 126 is disposed at the bottom of the annular packing box 65 and is located below the lower seal set. The lower surface of the lower matching ring 126 is in contact with the bottom surface of the packing box 65, and the two are complementary to each other. Compliant ring 125 is disposed between bottom surface 127 of packing retainer 67 and upper seal set 119. Compliant ring 125
The upper end surface is in contact with the bottom surface 127 of the packing retainer 67 and has a correlation. An intermediate matching ring 129 is disposed between the upper seal set 119 and the lower seal set 121. The upper surface of the lower conforming ring 123, the lower surface of the secondary conforming ring 125, and the upper and lower surfaces of the intermediate conforming ring 129 are all in the shape of a truncated cone, and the angle of the cone is as follows:
Upper and lower seal cellars in final assembly position) 119, 12
It is set to match the shape of 1. To explain this point, FIG. 2B shows the sealing member of the present invention installed in the valve, but before the packing retainer 67 is tightened to hold the sealing member. on the other hand,
Figure 2A shows the packing retainer 67 with a threaded neck 69.
Hold the seal member and tighten each seal set 1.
19,121 and each matching ring 123.125.12
9 is the final assembly position. As will be described in detail below, the metal ring gasket 161 of each seal set 119, 121 has a conical shape that is sharper than the surface of each matching ring. That is, the angle of the cone of the metal ring gasket 131 is at the second position compared to the final tightening position in FIG. 2A.
It is small in the state before tightening shown in Figure B.

In some cases, one or both of the lower matching ring 123 and the secondary matching ring 125 may be omitted, but in this case, the bottom surface of the packing box 65 or the bottom surface of the packing retainer 67 may be placed at a predetermined angle and in a predetermined plane. It is necessary to make it into a truncated cone shape with . Compatible ring 123.125.
129, these would need to be made of a fairly hard material such as 4140M, but the valve body and bonnet 26 may be made of conventional high pressure valve steel.

Since the upper and lower sealers 119 and 121 are the same, it is sufficient to describe only one of them in detail. The seal set 119 has a structure in which two identical assembly rings 136 are arranged between a pair of truncated conical metal ring gaskets 161.

This assembly ring 156 is made of a solid lubricant material that is flexible and has a smaller elastic modulus than the metal ring gasket 131. One of the assembly rings 163 is disposed adjacent to one of the metal ring gaskets 131 and the other assembly ring 133 is disposed adjacent to the other metal ring gasket 161.

A core ring 165 is disposed between assembly rings 163. The thermal expansion coefficient of the core ring 165 is smaller than that of the hollow ring 136. core ring 16
5 is also larger than the inner diameter of the assembly ring 163. A bearing ring 167 is disposed between the core ring 165 and the operating stem 51 over the inner circumference of the core ring 165 . The bearing ring 167 is made of a strong, flexible, solid lubricant material similar to the material used to form the assembly ring 163. Bearing ring 137 slips into a hole formed in core ring 135 .

The cross-sectional shape of the metal ring gasket 131 is approximately polygonal before being tightened, and the cross-sectional shape is about 3 mm with respect to the horizontal plane.
It is tilted at an angle of 0°. Therefore, before being tightened, the conical angle of the metal ring gunnut 131 is about 1200 degrees.

Also, before the metal ring gasket 161 is tightened, a gap is formed between the operating stem 51 and the packing box 65 and the peripheral edge of the metal ring gunk 1310, so the metal ring gunk 161 is not inserted into the pulp. During installation, the operating stem 51 and the packing box 65 will not be damaged. The metal ring gasket 161 can be set in place by simply dropping it. When the packing retainer 67 is tightened to tighten the sealing member, each metal ring gasket 131 is compressed and their inner diameters are significantly reduced while their outer diameters are significantly increased. Therefore, the inner peripheral edges on the four sides and the outer peripheral edge on the convex side of each metal ring gasket 131 are deformed.

In other words, each metal ring gasket 131 is deformed and engaged with the operating stem 51 and the packing box 65, respectively, so that metal-to-metal sealing is performed. Operating stem 5
The metal ring gasket 161 must be made of a softer metal than the operating stem 51 so that the metal ring gasket 161 is not worn or damaged. For example, a Mone/L/(K Monel ) alloy may be used for the motion stem, although any suitable steel may also be used. The surface of the operating stem 51 is coated with a hard coating of tungsten carbide or the like at 3 to 5 mm/L/(7.6 x 10" to 12.7 x 1
It is desirable to apply the coating to a hardness of 0'ff1) to increase the hardness of the surface of the operating stem 51 and increase its durability. By applying such a coating, the hardness of the working stem 51 is increased by about 60 to about 60 Rockwell hardness. Since the metal ring gasket 131 has sufficient plasticity, it can be sealed between metals by applying high stress and deforming the peripheral edge, and has sufficient strength, so it can withstand high preloads applied and from wells. Can withstand fluid pressure flowing out. For example, this metal ring gasket 161 is 131
It is made of annealed stainless steel (aunutenitic stainless steel) such as 6 stainless steel, or other metal such as carbon steel 1 alloy steel. In order to minimize wear and damage on the operating stem 51, when rounding the inner peripheral edge on the concave side of each metal ring gasket, the radius should be approximately half the thickness of the metal ring gasket 161. It is desirable to do so. For example, the thickness of the metal ring gasket 161 is 0.
．． 04 inches (If it is 1,011, the inner circumference is 0.02
It is best to round with a radius of inch (0, f5). In the tightened state, the metal ring gasket 131 forms an angle of about 15° when horizontally rolled, so its cone angle is about 150°.

On the other hand, the truncated conical surfaces of the matching rings 123, 125, 129 are also self-aligned at an angle of about 15° with respect to the horizontal. Therefore,
Each metal ring gasket 1 is connected to each matching ring 123.
, 125.129 fits the truncated conical surface. Incidentally, the metal ring gasket 161 is preferably shaped like a trapezoid, but it goes without saying that it may be shaped like a truncated cone with a different angle.

The materials of assembly ring 133 and bearing ring 167 must have a low coefficient of friction. In other words, the material needs to have high lubricity.

The materials for assembly ring 133 and bearing ring 167 must also be strong and durable enough to maintain their integrity under high pressure, yet be chemically stable to the fluids controlled by the valve. Expected vomiting temperatures during pulp operations, e.g. 600°F to -20°F (14
It is also required to be able to withstand temperatures of 9°C to -29°C. Such materials have sufficient elasticity or plasticity,
It must be able to penetrate into 5Ji-axis gaps.

The gap referred to here is the metal ring Ganuga)131. A gap formed between the operating stem 51 and the packing box 65, which is caused by scratches or mechanical marks formed on the operating stem 51 and the packing box 65, or during and after the operation of the operating stem 51. This is the gap created by the metal ring gasket 161 and the new surface of the operating stem 51 being adjacent to each other. The latter type of gap may occur, for example, during and after the operation of the operating stem 51.
This occurs because the inner peripheral edge of each metal ring gasket 131 is not simultaneously and constantly plastically deformed to conform to the newly adjacent operating stem surface.

The assembly ring 133 and the bearing ring 137 penetrate into such minute gaps as described above to exert a sealing effect. Therefore, this assembly ring 166 and bearing ring 137 can be considered as a seal ring. Materials for the assembly ring 166 and bearing ring 167 include Teflon (
Teflon) J or “-t U Teflon
(Moly-Teflon) J is a suitable polytetrafluoroethylene polymer. Here, Moriteflon is similar to Teflon, but
Contains 15% selipden disulfide (MnS2) on the rough surface, among which 5% MnS2 in terms of flux density.
The best choice is one consisting of nS2 and 95% tetrafluoroethylene (TF"E), which is manufactured by Allied Chemical Compa.
Y) is sold as l-1k 2021 J.

As with the case of the assembly ring 13 and the bearing ring 167, the material for the core ring 135 must be strong enough to withstand the high preload required for sealing, and the material must be strong enough to withstand the high preload required for sealing. chemically stable to υ and the temperatures expected during pulping operations, e.g.
59℃).

Another feature of the core ring 165 is revealed by applicants' findings that may be the cause of leakage when SMT type seals are used under high pressure and with severe thermal expansion. However, it should be understood that the seal disclosed here is not a theoretical solution to the problem of leakage.

After temperature cycling, using rings formed of TF'E or TFE with MnS2, 30.000 psi (
When applying pressures in the range of 2,100 k (J/cyl), it is clear that the leakage seen in SMT type stems is due to a partial loss of prestress applied to the seal. A comparison can be made with the loss of preload applied to a pure elastomer packing disclosed in the ASMF article cited above. When constructing an SMT type seal, tightening the packing retainer applies mechanical pressure to the seal, which pressure is greater than the pressure exerted by the high pressure fluid. When a bulb with SMT-type Nutestale is heated from room temperature to 600°]' (149°C), the ring formed of TF'E expands, but not over a large range. This is because these rings are surrounded on almost all sides by metal, and the expansion rate of the metal is slow compared to these rings. Therefore, the preload force applied to the seal becomes higher than the original pressure, that is, the pressure before heating. When the valve is completely cooled to room temperature, the preload not only decreases from the pressure increased by heating the valve, but also becomes lower than the original pressure. This is due to one or both of the following effects. The valve is approximately 600°F (149°C)
When heated, the ring formed by TF'E thermally expands, increasing the pressure applied to the seal and the surrounding metal, resulting in a higher preload and deformation or yielding of the metal surrounding the circumference of V1. occurs, so when the seal part is cooled again at room temperature, the volume occupied by sea μ increases and the pressure applied to the seal becomes smaller than the original preload. Also, the valve is 60
As thermal expansion occurs by heating to 0°1' (149°C) and the pressure applied to the TFE ring increases, the TF'E ring undergoes a permanent deformation that is greater than the deformation caused by the preload, i.e. It will undergo large compressive deformation. Since this deformation is not reversed even when the valve is cooled to room temperature, the pressure on the TF'E ring is reduced and the packing retainer offsets the pressure on the seal somewhat. Therefore, after being subjected to temperature cycling, it is necessary to retighten the packing retainer to obtain an appropriate preload.

If you do not retighten this valve, it will cost 30,000 yen.
When used against pressures on the order of psi (2,100 kti/d>), the seal portion will struggle.

In this invention, instead of TF'E or MnS2-added TF'E sandwiched between the metal ring gas guts of the SMT type stem seal, TFB or MnS2
A material with a smaller expansion coefficient than TFE doped with nB2 is used. In a preferred embodiment of the invention, such a low expansion material is used for the core ring 165, and six sides of the core ring 135 are connected to the assembled ring 13.
6 and adjacent the metal ring gasket 131 and the operating stem 51 via the bearing ring 167.

Therefore, the coefficient of thermal expansion of the core ring 135 is
3 and the coefficient of thermal expansion of the bearing ring 137. Suitable materials for core ring 135 include:
Relca has dense graphite, this is [Cura 7]
It is commercially available under the trade name #I/l/ (Grafoil) J. For this, U.S. Patent No. 3.40
Reference is made to issue 4.061. Although the exact figures are unknown, for example, it is said that the thermal expansion coefficient of TF″E is several times larger than that of graph oil. However, according to official data, The coefficient of linear expansion of graphite produced as a thin layered ribbon is as follows:
70°F to 2.0[]0°F (21 to 1.093°C
) within the range of approximately -(1,02X 10-5in/in raw (
-0,04x10-5α/Taku ℃) and 70°F to 4,00.0'F' (21 to 2,2
04°C) in the range of approximately j, 5 x 1Q-”in/in’
F(2,7xi D-"c/m℃) f, T); b
. TFE wire 11g 1m rate c, 78°F to 500°
F (26-260°C) about 7, [l ~ 1 o,
ox'+ 0-51n/in''P(12,6-18.O
Xl 0-5ffi/m°C). In the case of a solid, the coefficient of body expansion is approximately six times the coefficient of linear expansion. Regarding this, please refer to the
The Handbook of Chemistry and Physics 7,
Try and Physlcs) 48th edition, P-9
See page 0 (Chemical Rubber Company, 1967). Now, even if we assume that the body expansion rate of Gouffoy 7 is five times as large as the linear expansion rate, its body expansion rate is approximately 78°F to 300°F (26 to 149°C).
It is 1/4 or less of the coefficient of body expansion of TF''E in the temperature range of .

The ring layer sandwiched between the metal ring gaskets (hereinafter referred to as a sandwich layer) includes a core ring 135, a bearing ring 137 disposed along the inner circumference of the core ring 165, and a core ring 135 and a bearing ring 137 disposed along the inner circumference of the core ring 165. It consists of an assembly ring 133 disposed adjacent to the upper and lower surfaces of the bearing ring 167, and when the metal ring gasket 161 is pressed and held,
It deforms according to the shape of the space formed between the metal ring gaskets 161, filling almost the entire space. The original cross-sectional shape of the pinch layer ring is rectangular, but it may be modified to fit the frustoconical shape shown on the right side of FIG. 2 before being installed in the bulb. Its shape is compatible ring 123.125
．． 129, into which a metal ring gasket 1.211 is pressed. Furthermore, when the ring of the sandwiching layer is attached, the original cross-sectional shape is rectangular, and by forming the seal, it is deformed into a truncated conical shape.

The material for forming the pressure relief core ring 165 is a graphoil ribbon tightly compressed and rolled into a rigid, seamless ring. This Yona Ribbon is made of Union Carbide Corbo V-C, Y (Ilnio
n Carbide Corporation),
It is commercially available under the name Graphoil Ribbon e-bag and is described in Union Exposed Carbide Corporation's technical report L524-204, a copy of which is attached as Appendix I to this product. . A tightly wrapped ring of Graphoil Rihon Bag exhibits a high coefficient of thermal expansion in the radial direction when placed around the working stem in the packing box, ie, in the direction of the working stem and the packing box. Further, the core ring 135 may be formed by cutting a sheet of graph oil, or may be formed by stacking sheets. Commercially available graph oil can be compressed to about 7096 to make it dense, but 100% or complete compression can be done either before installation as mentioned above, or by installing it inside the valve and then forming the sea μ. It may be compressed by

Assembly ring 133 is thinner than core ring 135 and bearing ring 167. This assembled ring 133 has approximately the same thickness when the core ring 135 is fully compressed, but has a radial width of 1 core ring 135. Both bearing rings 137 are wide. The radial width of core ring 135 plus the radial width of bearing ring 137 is approximately equal to the radial width of assembly ring 136. If a sandwich layer is installed in the valve, the assembly ring 136
and bearing ring 137 form a slidable strip fit. When this sandwich layer is pressed together by forming a seal, the assembly ring 165 and the bearing ring 13
The inner circumferential edge of 7 is pressed against the operating sdem 51,
The outer peripheral edges of the assembly ring 166 and the core ring 165 are brought into sealing engagement with the wall surface of the packing box 65.

Two sealers) 119 and 121 are shown in the diagram,
The applicant of this invention believes that a sufficient sealing effect can be obtained by using the entire seal set. That is,
The second set of seals is installed as far away from the fluid to be sealed as possible and is for emergency or backup use in case the first set of seals is damaged.

Another feature of the emergency or backup seal is that a passageway 169 is formed in the bonnet 23. This passageway 139 coincides with the passageway 141 formed in the intermediate matching ring 129 to form a flow path when the seal is formed. The passage 139 is also connected to an injection fitting 1 disposed in a threaded socket installed on the outside of the bonnet 26.
It communicates with 40. →−“−An annular groove 143 communicating with the passage 169 is formed in the wall surface of the packing box 65, and an annular groove 145 communicating with the passage 141 is formed in the intermediate fitting ring 12.
It can be formed at the inner end of 9. Seal part, )119,1
21 is damaged, the seal material is removed from the injection fitting 14.
0 and passages 139, 141, annular 5143, 1
45, the packing box 65 and the operating stem form an emergency or backup seal, respectively.

The sealing device of the present invention applies preload by tightening the packing retainer 67.

The pressure in this case is greater than the pressure exerted by the fluid when operating the pulp. The pulp shown in FIG.
, 100 kg/i) is approximately 37,500 pSi C2,625k
(c)).

The pulp having the stem seal device of the present invention is heated from room temperature of about 70°F (21°C) to about 600°F' (149°C) by flowing a fluid through the pulp, etc.
There is no need to re-tighten the packing retainer even if it is then cooled down to room temperature again. Therefore, the initial prestress applied to the pulp is maintained during temperature cycling. This is due to the following facts. That is, the pressure caused by the thermal expansion of the sandwiching layer between the metal rings 131,
In other words, the initially applied preload is insufficient to permanently deform the metal-surrounded portion of the pulp adjacent to the seal, but the reason is that the shear expansion rate of the core ring 165 is greater than that of the assembled ring 136 and This is because it has a small smell compared to the bearing ring 167. For the same reason, since the pressure applied by heating is low, the assembly ring 133 and the bearing ring 137 will not undergo permanent deformation, that is, compressive strain, and the rings 163 and 137 will be cooled. Even if it loosens, there is no risk of loss of preload.

According to the applicant, the stem seal device of the present invention has -2
Temperature cycling from 0°F to 300°F (-29 to 149°C)
A: It is said that even if it is applied to the fluid of ri/d), it can be used satisfactorily without having to retighten the packing retainer. In this case, the assembly ring 166 and bearing ring 137 are MnS2
The core ring 165 is made of graph oil, and the volume of the core ring 1 and the core ring 5 is about 1/6 of the volume of the entire sandwiching layer.

Therefore, in this preferred embodiment, assembly ring 13
6 and the bearing ring 167 is approximately twice the volume of the core ring 135. The material forming the assembly ring 136 is made of metal ring gasket 161 by forming a sea μ.
Graphoi/l/1!, which is disposed between this assembly ring 136 when forming the seal, without being forced out of the seal. !
! The core ring 16 surrounds the core ring 165 before a metal-to-metal seal is formed between the metal ring gasket 131 and the operating stem 51 and the packing box 65.
5 is prevented from being pushed out beyond the metal ring gasket 131. In addition, a bearing ring 167 made from TF'E containing 596 MnS2 and arranged along the inner circumference of the core ring 165 made from Graffoy/l' reduces friction between the operating stem 51 and the stem seal device. At the same time, excessive wear of the core ring 165 is prevented. Therefore, the core ring 165 made of Graphoil has a small coefficient of thermal expansion, and its five sides are T F' E containing 5% MnS2.
The operating stem 51 and the metal ring gasket 131 are in contact with the operating stem 51 and the metal ring gasket 131 through an assembly ring 136 and a bearing ring 137. In this case, in the sandwiching layer of the present invention, the volume of the core ring 135 is equal to that of the assembly ring 133 and the bearing ring 1.
It is desirable to have approximately 1 out of 37 total volumes. Of course, the volume ratio of the ring in the sandwiching layer may be changed, and the material of the ring may also be changed.

In FIGS. 1, 2A, and 2B, the conical shape of the metal ring gasket 161 and the ring of the sandwich layer is
Although the direction of the sealing pressure is opposite to the direction of the sealing pressure, the sealing portion may be reversed as long as the surfaces of the inner peripheral edge and the outer peripheral edge of the sealing portion are parallel and the secured state is the same. Therefore, the conical shape of each ring of the metal ring gasket 161 and the sandwich layer can be oriented in the same direction as the pressure of the sea/I/crumble fluid. In addition, the assembly ring 136 and the bearing ring 167
It will also be understood that they do not necessarily need to be formed separately. For example, along the center of the outer circumference of a cylindrical ring,
It is also possible to form a member in which a groove is formed within the unit and the cross-sectional shape thereof is U-shaped. In this case, the core ring is aligned within the groove before being placed into the pulp.

Although a preferred embodiment of the invention has been described, numerous modifications may be made by those skilled in the art without departing from the spirit of the invention. Therefore, it should be understood that the disclosure herein is for illustrative purposes only and is not intended to limit the scope of the invention. The scope of the invention is indicated in the claims.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the pulp of the invention, and FIGS. 2A and 2B are views of the pulp of the invention in which the frustoconical metal ring gasket is oriented opposite the pressure with which it is sealed against the inside of the valve. FIG. 2 is a partially enlarged cross-sectional view taken along the same plane as FIG.
Fig. 2B is a partially enlarged sectional view of the stem seal device of the present invention installed in the valve before tightening the vasogin retainer, and Fig. 2A is a partial enlarged sectional view of the stem seal device fif after tightening the packing retainer. Partial enlargement 1υ" is a side view. 51...Operating stem 61...Boat 63
．． 10'l...Seal member 65.103...Packing box 67.1r15...Baggin retainer 131...Metal ring gasket 166...Assembly ring 135...Core ring 167...Bearing ring Application People Smith International Incorporated"j1! Person Patent Attorney LE Hidehiko Oka Voluntary procedural amendment (method)

Claims (9)

[Claims] (1) The packing box has a port at the bottom thereof, and an operating nut capable of moving in the axial direction of the pulp extends through the port to the outside of the packing box, and is used under high pressure and temperature cycling; A sealing device that seals between a wall surface of an operating stem and a packing box installed around the operating stem, the first and second sealing devices installed in the packing box installed around the operating stem. 2 metal ring gaskets, and a deformable annular sealing member sandwiched between the metal ring gaskets in the packing box, and the sealing member is arranged in the first and second metal ring gaskets adjacent to the metal ring gasket. 2 annular portions and a core portion disposed between the annular portions, the annular portion being formed of a strong deformable material, and the core portion having a thermal expansion coefficient greater than the material forming the annular portion. A sealing device characterized in that it is made of a material with a small sealing ratio. (2) The first and second (1); The sealing device according to claim 1, wherein the material forming the one-shaped portion has a small coefficient of friction. (3) The first and second annular portions are made of tetrafluoroethylene polymer, and the core portion is made of dense graphite. sealing device. (4) The material forming the first and second annular portions is
7. A sealing device according to claim 6, characterized in that it contains up to about 15% molybdenum disulfide. (5) The first and second annular portions are comprised of assembly rings that engage and seal with the operating nut and the packing box, and the core portion has an inner diameter larger than an outer diameter of the operating nut. A patent comprising a core ring, further comprising a bearing ring formed of a durable deformable material, disposed along the inner circumference of the core ring, between the core ring and the operating stem. A sealing device according to claim 4. (6) The sealing device according to claim 5, wherein the bearing ring is made of the same material as the assembly ring. (7) The core ring and the bearing ring occupy almost all of the space formed in the axial direction between the assembly rings and the space formed in the radial direction between the operating stem and the packing box. The sealing device according to claim 6, characterized in that the sealing device satisfies the following. (8) The sealing device according to claim 7, wherein the volume of the core ring is approximately 1/2 of the total volume of the assembly ring and the bearing ring. (9) The coefficient of thermal expansion of the material forming the core portion is 1/1/2 of the thermal extensibility of the material forming the first and second annular portions.
4. The sealing device according to claim 1, wherein the sealing device is smaller than 4. On further comprises a member for pressing the first and second metal ring gaskets, the member partially flattening the metal ring gaskets and deforming the inner and outer peripheral edges of the metal ring gaskets so that the operating stem and the second metal ring gaskets are pressed together. Claim 1, characterized in that the first and second annular portions of the seal member are engaged with and sealed with the packing box, and the first and second annular portions of the sealing member are engaged with and sealed with the operating stem and the packing box. The sealing device according to item 1. 01) The outer peripheral edge of the annular core portion is adjacent to the Mil packing box, the inner diameter of the core portion is larger than the outer diameter of the stem, and the sealing member has a sixth annular portion, 11. A sealing device according to claim 10, wherein the annular portion is made of a material that is malleable and is disposed between the core portion and the stem. Q')J Said No. 1. 12. The SEA/L/device of claim 11, wherein the second and sixth annular portions are formed of tetrafluoroethylene polymer and the core portion is formed of dense graphite. 03 Above 1. When the second and sixth one-section parts are made of a material consisting of 95% tetrafluoroethylene polymer and 596 molybdenum disulfide, and the core part is made of dense graphite, and the metal ring gasket is compressed. ,
Almost the entire space formed between the metal ring gasket, the operating stem and the packing box is covered by the first. The sealing device according to claim 11, characterized in that the sealing device is occupied by the second and sixth annular parts and the core part, and the volume of the core part is about 1/6 of the total volume of the space. .