JPH0276972A - V-packing device - Google Patents

Abstract

PURPOSE:To enable maintenance of excellent sealing ability not only at a high temperature high pressure but also at a low temperature by a method wherein a title device is formed with a V-packing made of PTFE and V-packings made of PTFE-filled graphite between which the front and the rear of the former V-packing is nipped in a back-up manner. CONSTITUTION:Female and male adapters 6 and 7 made of a metal are situated in a gap part 4 between a shaft part 2 and a hole part 3 of a housing 5, and three V-packings 11, 10, and 11 are located therebetween. The central packing 10 is made of PTFE, and the packings 11 on the both sides are made of PTFE- filled graphite. This constitution simplifies a shape and enables maintenance of sealing ability throughout a temperature area of all of a high, a normal, and a low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a V-packing device, and more particularly to a V-packing device for high temperature and high pressure applications.

[Conventional technology and its problems]

Conventional V-packs are made of rubber or PTFI! Materials such as these have been used. There were no problems with this material when used at room temperature. However, at high temperatures exceeding 300°C, PTFE and other materials soften significantly, and at high pressures, they protrude from the gap in the sealing area and flow away, resulting in failure to form a seal.
At low temperatures of about 50°C to -200°C, the overall diameter shrinks due to the difference in linear expansion coefficient, causing separation between the outer lip and the inner circumferential surface of the hole, resulting in loss of sealing performance. cormorant.

SUMMARY OF THE INVENTION An object of the present invention is to provide a V-packing device that can withstand high temperatures and high pressures and maintain sealing performance, as well as maintain excellent sealing performance even at low temperatures.

[Means for solving problems]

The present invention provides a V-packet made of PTFE and the PTFEI! !
V PTF that holds the front and back of Harakin in a backup manner
E-filled grite V-packet.

[Effect]

PTFE at room temperature! ! The inner and outer lips of the lV packing contact the outer circumferential surface of the shaft and the inner circumferential surface of the housing hole with a predetermined tension, respectively, and perform a sealing action.At high temperatures of 300°C or higher, the intermediate PTFtl V packing It softens, but the PTF before and after [! The filled graphite V-packet maintains sufficient hardness, prevents the softened PTFE V-packet from being washed away, and maintains sealing performance.

At low temperatures of -50°C to -200°C, the intermediate PTFIi V-packing contracts and its inner lip forms pressure contact with the shaft to perform a sealing action on the inner diameter side, while the front and rear PTFE-filled graphite V-packings Due to the hysteresis, the lip on the outer diameter side comes into pressure contact with the inner peripheral surface of the housing hole and performs a sealing action on the outer diameter side.Therefore, by combining at least three V-packets, both the inner and outer diameters can be sealed.

〔Example〕

The illustrated embodiment will be explained in detail below.

FIG. 1 is an enlarged sectional view. 2 and the housing 5 rotate about the axis lJi relative to each other. Or relatively slide in the axial direction. The right side of the figure is the high pressure chamber side, and the left side is the low pressure chamber side.

6.7 is a female adapter and a male adapter, respectively, which are made of metal such as brass or stainless steel, and the former has a V-shaped groove 8 with an angle T.
The latter is a ring body having chevron-shaped protrusions 9 each having an angle β, and both angles T9 β are set to be approximately equal or completely the same.

Between the male and female adapters 6 and 7, there are three pieces of ■Packskins 1.
1. to, 11 are interposed. The central ■packet 10 is made of polytetrafluoroethylene□rPT in the present invention.
FEJ is a single layer (of course, a small amount of filler material such as graphite or molybdenum disulfide may be added), and on the other hand, a pair of V-packets ILII that sandwich this from the front and back in a backup manner are made of PTFE. Made of filled graphite.

The latter V Packkin 11.11 uses powdered graphite and PTF [!] as a binder. After filling and mixing 2 to 40% □, preferably 5 to 20% □ of the powder, the mixed powder is pressed into a V-shaped cross-section, which is then fired.

The solid line in FIG. 1 indicates the unattached state □free state 11, and the v-shaped angle α of the central PTFE V packing 10 is the front and rear P
TFE-filled graphite packing 11. The shape is set so that the V-shaped angle γ or β of 11 has the following relationship. That is, α< γ α × β Therefore, as shown in FIG. 1, PTF[! Made by V Packkin 10
Only the top of the mountain side 12 is the V-patzkin 1 on the left side of the figure.
1 in contact with the center of the V-shaped groove, and PTF[! Only the inner and outer edges of the valley side surface 13 of the V-packet 10 contact the inner and outer edges of the protrusion surface of the V-packet 11 on the right side of the figure. In this way, with the center V packing 10 as a reference, the ridge side 12 has a 7-shaped groove-shaped gap 14.15 that is open to the inner and outer diameters, and the valley side 13 has a boomerang-shaped or crescent-shaped gap 16. do.

As is clear from the free state shown in Fig. 1 and the normal temperature mounted state shown in Fig. 2, PTFEI! The inner diameter of the IV packing 10 is set to be slightly smaller than the outer diameter of the shaft portion 2, and the outer diameter is set to be slightly larger than the inner diameter of the hole 3 of the housing 5, so that both the inner and outer lips 17 and 18 are connected to the shaft. It comes into contact with the portion 2 and the hole 3 elastically (by the elastic urging force of the elastic member 19, which will be described later). In this way, PTF [! Made by V Packkin
A tension allowance (restraint force) is applied to O when it is attached at room temperature.

On the other hand, the inner and outer circumferential edges of the graphite packing 11.11 correspond to the shaft portion 2 and hole 3 with minute gaps 20.21, and do not provide tension (restrictive force) (when installed at room temperature).

As shown in FIG. 2, the male adapter 7 is connected to a plurality of I
A resilient member 19 such as a spring receives a resilient force in the direction of arrow F. That is, when the right end of the resilient member 19 is pressed with a tightening tool (not shown) from the state shown in FIG. The manufactured V-packet 11 acts as a wedge, so to speak, and the PTF [! The V-shaped angle of the manufactured V-packet 10 is widened to provide more tension, thereby increasing both the inner and outer lips 17.1 of the V-packet 10.
8 in resilient contact with the shaft, 2 and hole 3, respectively.
- Generates a binding force to ensure □ sealing.

Note that it is desirable to use metal such as stainless steel for the resilient member 19 and the resilient member receiver 22.

Next, from the normal temperature state shown in this Figure 2,
When the temperature reaches 00℃, as shown in Fig. 3, Pt
FI! The volume of the filled graphite V-packet 11.11 expands, and the inner and outer circumferential edges contact the circumferential surfaces of the shaft portion 2 and the hole portion 3. In particular, since a small amount of gas is generated at the above temperature from the PTFE mixed as a binder, a definite expansion of the layer occurs, and the microvoids 20, 21 shown in FIG. 2 disappear. On the other hand, under such high temperatures, PTFI! l! lV
The packing 10 softens to about 1011 Po1se. The above-mentioned PTFI! Filled graphite V-packet 11.
11 maintains the airtight state, prevents leakage, and maintains high-temperature, high-pressure sealing performance as a whole.

When the temperature drops from this high temperature state to -50°C to -200°C, as shown in Figure 4, the diameter of the PTFE V-packing shrinks due to the difference in linear expansion coefficient, causing the outer lip to shrink. Although the portion 18 separates from the hole 3 and creates a gap 23, the inner lip portion 17 reliably contacts the shaft portion 2. Small arrows in FIG. 4 indicate the contact surface pressure distribution between the inner lip portion 17 and the shaft portion 2.

By the way, PTFE filled graphite V packing 11
, il leaves a restraining force on the outer diameter side of the housing 5 due to its own temperature hysteresis, and contacts the hole 3 of the housing 5 with a contact surface pressure distribution as shown by the small arrows in FIG. This acts as a seal on the outer diameter side.

In this way, the inner diameter side seal and the outer diameter side seal are each made of PTFE.
Made by V Packkin 10 and PTF [! Filled graphite lv packkin 11.11 is shared.

Here, PTFI! Made of filled graphite ■Patsukin 11
The unique temperature hysteresis of is explained below.

Figure 7! is the PTFE-filled graphite used in the present invention,
3 shows the temperature hysteresis of a conventional thermosetting resin or thermoplastic resin, respectively.

This Figure 7 1. In n, straight standing metal housing 5
indicates the inner diameter dimension of the hole 3, which increases gradually with temperature rise due to its small coefficient of linear expansion.

Therefore, as shown in Fig. 7 (■), the dimensions (outer diameter) of the conventional resin change to A-B-C-C''-E □, that is, the arrow ■■
■■■ The initial gap T1 increases to the gap FJtTa (even if the temperature returns to the same temperature again).

In contrast, the PTFE-filled graphite according to the present invention is shown in FIG. As shown, A -B -C→B-
E - that is, the temperature changes sequentially as indicated by the arrows ■■■■■, and when the initial gap S1 returns to the same temperature, it becomes zero. The temperature at point 0 in Figure 7 I is approximately 300°C to 35°C.
It is 0°C.

To explain in more detail, in conventional resin products, the seventh
As shown in Figure ■, the initial period B!Tt is at room temperature, and as the temperature rises, A-B and the resin sealing material (ring) freely expand, but at point B there is no hole. This expansion is suppressed by the hole in the metal with a low expansion coefficient and reaches the 0 point in contact with the inner circumferential surface of the part.With conventional resin, in this regulated state, the expansion reaches 80 in Figure 7 (■). Creep occurs by the amount shown by
The contact surface pressure is significantly reduced. Then, when the temperature drops,
The sealing material (ring) and the hole contract together until point C', which is extremely close to the 0 point, but due to the creep shown by Δe above, there is no squeezing allowance, and this point C' It contracts as shown by the arrow Φ and reaches point E, where the initial gap T
This results in a gap T3 larger than 1.

On the other hand, the sealing material (ring) made of graphite containing fluororesin according to the present invention is shown in Fig. 7! As shown in the figure, there is a gap S1 at room temperature, and as the temperature rises, it freely expands along lines AB, and is suppressed by hitting the inner peripheral surface of the hole at point B. As the temperature rises thereafter, it expands slowly while being regulated by the metal holes, as shown in B-C. In this regulated state at high temperatures, the fluororesin contained in the graphite internally generates gas, forming many independent pores in the graphite, and attempting to increase its volume. However, since this is restricted by contact with the inner circumferential surface of the hole, internal stress and contact surface pressure increase. In other words, the seventh [
Δd of f can be seen as a crushing margin.

After that, as the temperature sequentially decreases from C-B-E (i.e., As a result, a crushing margin can always be ensured, and as 53-0, no gap is created between the hole and the inner circumferential surface of the hole.

In this way, the present invention uses PTFEI V packing 10, which has a unique temperature hysteresis, before and after the intermediate soft PTFEI V packing 10.
Since it is held between V-packets 11 and 11 made of FE-filled graphite, it can reliably seal in a wide temperature range from high to low temperatures.

In addition, as shown in FIG.
It is also preferable to use a set of PTFE-filled graphite V-packs 11 and 11 at both the front and rear ends, and between them, PTF [! Made of V buffy yio, io and PTFE filled graphite I! IV gaskets 11 are interposed alternately. Of course, you are free to use about 3 or more sets.

In addition, as shown in FIG. 6, a V-shaped backup ring 24.24 is made of polyimide resin with a usable temperature of -250°C to +420°C, and the front and rear ends are connected to the polyimide resin bank up ring 24.24. It is also desirable to clamp the V-packets 11, 10 and 11. It is also preferable to use a polyimide resin mixed with a filler such as graphite, carbon, or silicon.

〔Effect of the invention〕

The present invention has the following significant effects with the above-described configuration.

■ Can maintain sealing performance in all temperature ranges: high temperature, room temperature, and low temperature. In other words, it can be applied to harsh environmental conditions that conventional materials cannot withstand.

■ Simple structure and shape and high reliability

[Brief explanation of the drawing]

Fig. 1 is an enlarged cross-sectional view of essential parts of an embodiment of the present invention in a free state (Fig. 2 is a cross-sectional view of the same in a normal-temperature mounting state, Fig. 3 is a cross-sectional view of the same in a high-temperature state, and Fig. 4 is a cross-sectional view of a low-temperature state). The same cross-sectional view of the state, No. 5
6 and 6 are sectional views of main parts showing another embodiment, and FIG. 7 is a temperature hysteresis curve diagram. 10...PTFE V packing, 11...MFI!
Filled graphite V-packet. Patent applicant: Space Exploration Agency
Mitsubishi Heavy Industries, Ltd. Same as above Mitsubishi Cable Industries, Ltd. Figure 1 Figure 1 Figure 3 Figure 2 Figure 4!

Claims (1)

[Claims] 1. A V-packing device comprising a PTFE V-packing and a PTFE-filled grite V-packing that clamps the front and rear of the PTFE V-packing in a backup manner.