JPS62251573A - Ring seal packing for superhigh pressure apparatus - Google Patents

Abstract

PURPOSE:To make the deformation in packing itself hard to occur, by forming a cross section of the packing into an inversed V-shaped form, and making deformation resistance at both ends larger than the central part, in addition. CONSTITUTION:A cross section of ring seal packing shows an inversed V-shaped form or an inversed U-shaped form, and an apex angle theta1 at the projection side is formed so as to become larger than an apex angle theta2 at the dent side. Doing like this, the thickness in the central part of the inversed V-shaped form becomes smaller than that in a tongue piece part, and since a side of deformation resistance in thick tongue piece part becomes larger than that in the central part, a deformation quantity in the tongue piece part is checked down to less than the specified limit. In consequence, the deformation in a packing presser due to deformation in the seal packing is prevented from occurring and, what is more, a breakdown at the central part on the packing presser dent side is also hard to occur.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an annular seal gasket disposed in the sliding part of ultra-high pressure equipment, and more specifically, the present invention relates to an annular seal gasket that is provided in a sliding part of an ultra-high pressure device, and in particular, has excellent durability under harsh operating environments with large pressure differences. This relates to an annular seal packing that indicates the characteristics of the product.

[Prior art] High pressure generation methods include liquid column, phase change, thermal expansion, chemical reaction,
Although there are methods such as light exposure and mechanical compression, methods using mechanical compression are widely used in industry, and among these methods, the piston-cylinder method is most commonly used along with the anvil method.

Various measures have been taken to increase the pressure generated in such piston/cylinder type high pressure devices, and ultrahigh pressure devices that repeatedly generate pressures of 1000 g/cm or more have also been developed.

FIG. 3 is a cross-sectional explanatory diagram illustrating a piston-cylinder complete ultra-high pressure device, in which 1 is the high-pressure container body, 2 is a block, and
3 indicates a piston, respectively.

In order to stably generate ultra-high pressure in such equipment, it is essential to provide a high degree of sealing between the ultra-high pressure chamber 4 and the outside world (atmospheric pressure), and the contact points of each part are provided with a sealing structure (
For example, O-ring attachment). However, dynamic friction occurs on the sliding surface between the piston 3 and the container body 1, and rolling occurs in the O-ring, so assuming that the sealing function does not deteriorate even if the piston advances and retreats many times, for example, as shown in the figure. It is recommended to install an inverted V-shaped gasket.

That is, as shown in the figure, a cylindrical packing case 5 having a hook-shaped cross section is fitted between the container body 1 and the piston 3, and the above-mentioned inverted V-shaped annular packing case 5 is inserted into the space sandwiched between the inner surface of the packing case 5 and the outer surface of the piston 3. A plurality of seal gaskets 6 are stacked, and a gasket presser (made of relatively soft metal, etc.) 7 and a holding member 8 are stacked on top of the seal gaskets 6. This holding member 8
I am positioning the patch while pressing it downward.

With such a sealing structure, when the high-pressure fluid in the ultra-high pressure chamber 4 enters the lower part of the annular seal packing 6 through the gap between the packing case 5 and the piston 3 and attempts to leak out of the system, the high pressure fluid will be removed. The pressure of the fluid acts to spread the tongues at both ends from the inverted V-shaped recess, and as a result, the tongues come into close contact with the outer circumferential surface of the piston and the inner circumferential surface of the packing case, thereby achieving a seal.

[Problems to be solved by the invention] However, since excessive pressure is applied to the annular packing used in ultra-high pressure equipment, an O-ring with good compressibility is desired, but as mentioned above, If we use soft rubber with good compressibility for the inverted V-shaped packing,
The amount of deformation of the tongue piece is too large, and as a result, the tip of the tongue piece may get stuck in the gap between the piston and the seal holder or the gap between the seal case and the seal holder.

However, since the inner circumferential surface of the annular packing is subjected to dynamic friction due to the movement of the piston 3, when the piston 3 moves back and forth while being bitten in as described above, the tongue portion is torn off within a very short period of time. For these reasons, ordinary flexible rubber materials cannot be used as the material for packings for ultra-high pressure equipment, especially inverted V-shaped packings. It is necessary to use materials with poor flexibility, such as cloth-filled rubber (especially Teflon-based materials, which have self-lubricating properties and are suitable as packing for sliding parts). These materials have high hardness, so the amount of deformation is small, so they are difficult to get stuck in the gap between the piston and the seal retainer, and because they have high self-lubricating properties, they can be dragged by the sliding piston and get stuck in the gap. few.

However, in ultra-high pressure equipment, the pressure in the ultra-high pressure chamber is extremely high, so when the maximum pressure is applied, the diameter of the container body 1'Ht and the packing case 5 should be expanded, while the outer diameter of the piston 3 should be slightly reduced. I've come to understand. As a result, the gap between the inner surface of the packing case 5 and the outer surface of the piston 3 expands, and even if it is an inverted V-shaped packing made of a hard material, the inverted V-shaped tongue part is pushed out, causing the inverted V-shaped packing to spread out. deformation will occur. When such deformation is applied to the inverted V-shaped packing, the packing presser 7 also undergoes a similar deformation, and the packing presser 7 has an inverted V-shaped bottom surface to match the upper surface shape of the uppermost inverted V-shaped packing. Stress concentration occurs in the center part A of the mold on the concave side due to deformation, and fatigue failure occurs due to the continuation of such stress concentration or repeated stress concentration due to batch operation, and finally the packing presser 7 is destroyed. It turns out. This tendency becomes stronger as the thickness of the packing increases. Further, due to the deformation of the packing presser 7, the packing presser 7
There is also a problem in that the end portion of the seal portion 8 bites into the shoulder portion B of the packing, causing damage to the portion 8.

The present invention has been developed in view of these circumstances, and is made of a material with high hardness that prevents the piston from getting stuck in the gap between the piston and the packing holder, and which allows the packing holder to remain stable even under ultra-high pressure. The object of the present invention is to provide an annular seal packing for ultra-high pressure equipment that does not cause fatigue failure or the like.

[Means for Solving the Problems] The annular seal packing of the present invention, which achieves the above object, is an annular seal packing disposed in the paddle part of an ultra-high pressure device, and has an inverted V-shaped cross section or an inverted V-shaped cross section. It has an inverted U shape, and the apex angle of the protruding side is 01. When the apex angle on the concave side is 02, θ
The gist is that it satisfies 1>θ2.

[Function] As can be understood from the deformation of the container body, packing case, etc. when ultra-high pressure is applied, the deformation of the inverted V-shaped packing is such that both tongues lift up around the center of the inverted V-shape. Occurs in That is, since the width of the packing storage space is deformed in the direction of widening due to the application of ultra-high pressure, the packing is deformed to fill the width of the storage space, and is compressively deformed by receiving high pressure from below. Therefore, although the packing is subjected to compressive deformation all over in the width direction, both ends in the width direction (tips of the tongue portions) are deformed more greatly.

When the amount of deformation of the tip exceeds a certain limit, the packing holder is also deformed due to the deformation, and the center part of the inverted V-shaped concave side of the packing holder, which is made of soft metal, cannot withstand the deformation and breaks due to fatigue. wake up

In view of the fatigue fracture mechanism described above, the present inventors believe that an effective way to prevent fracture is to strengthen the deformation resistance of the sealing gasket, making it difficult to deform, and thereby preventing deformation of the gasket retainer. As a result of various studies, we have arrived at the configuration of the present invention shown in the above configuration.

That is, when the cross section of the annular seal packing according to the present invention is enlarged, it has an inverted V-shape or an inverted U-shape, for example, as shown in FIG.
The inverted V-shaped packing will be explained below, but the same argument holds true for the inverted U-shaped. is formed. By adopting such a configuration, the thickness of the center portion of the inverted V shape is inevitably smaller than the thickness of the tongue portion. As a result, the deformation resistance of the thick tongue part is greater than that of the central part, so the amount of deformation of the tongue part is suppressed to below a certain limit, and as a result, the deformation of the seal presser due to the deformation of the seal pack. This prevents breakage at the center of the seal presser recess side. In other words, the breakage as described above occurs when a large tearing force is applied to the central part of the concave side of the packing holder, but in the packing according to the present invention, since the packing itself has a large deformation resistance, the packing holder has a large tearing force. The effect is small, and no large deformation occurs in the center of the concave part of the packing presser.
Therefore, the occurrence of fatigue failure of the seal holder is suppressed. On the other hand, the conventional gasket (θ1-0
In the case of 2), the deformation resistance of the gasket itself is small, and as the gasket deforms, the gasket presser also deforms and stress concentration tends to occur in the recessed portion, leading to breakage with a slight deformation.

When using the packing of the present invention that satisfies the above configuration, it is normal to stack multiple layers in the packing case (see Figure 4) as in the conventional case, but it is also possible to use only one packing. Included in invention. In addition, a plurality of ordinary rubber packings as shown in FIG. 2 are used as packing 1 according to the present invention.
The present invention also includes the case of combining a small number of pieces.

When applying the seal of the present invention to form a seal structure, for example, the above-mentioned annular seal may be stacked in multiple stages in the gap between the seal case and the cylinder, and a seal presser and then a holding fitting may be stacked on top of the uppermost seal.
It is also possible to give the packing presser a shape that applies the technical idea of the present invention and to make the packing presser itself perform the function of a packing. This makes it possible to prevent the second problem, that is, damage to the packing shoulder due to the packing presser. In other words, metal or hard resin with low hardness is generally used for the seal holder, and when high pressure is applied during sealing, the seal holder itself will deform slightly.Therefore, the seal holder is formed into an inverted V-shaped or inverted U-shaped cross section. , and if the protrusion side apex angle θ1 is designed to be larger than the recess side apex angle θ2, the same effect as described above can be expected. In this case, since the top surface of the protruding side of the seal presser is not flat but protrudes, the seal is held stably without being misaligned with the holding metal fitting whose bottom surface is formed into a concave shape correspondingly. be able to.

The packing according to the present invention needs to be made of a material that is hard enough to prevent it from biting into the gap between the piston and the metal fitting, which is a drawback of rubber packing, and examples of such materials include cloth-filled rubber materials, Teflon, carbon or Cu powder-containing Teflon, and carbon fiber-containing Teflon are recommended, but other relatively hard rubber materials, synthetic resins, etc. can also be used, and these materials can also be used in combination. In some cases, it is desirable to gradually increase the hardness from the high pressure side to the atmospheric pressure side. Other packings similar to the packing of the present invention may have a groove formed in the center of the recess side to make it easier for both ends to spread out, but when this packing is used for an ultra-high pressure device, the groove portion is on the high pressure side. Since the protruding top of the packing located at the sealing hole enters and the packing shape is irregularly deformed, the desired sealing effect is not achieved.

[Effects of the Invention] The present invention is constructed as described above, and since the deformation resistance at both ends of the inverted V-shaped packing is greater than that at the center of the inverted V-shaped cross section, deformation of the packing itself is less likely to occur. It has become possible to provide a seal structure for an ultra-high pressure device that is less likely to cause deformation force to be applied to the packing holder, so that the packing holder is less prone to breakage due to fatigue, and thus has an excellent sealing effect and excellent durability.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an annular seal packing according to the present invention, FIG. 2 is a schematic diagram showing a conventional annular seal packing, FIG. A schematic diagram for explaining destruction, and FIG. 5 is a schematic diagram showing another embodiment. 1... Container body 2... Block 3...
・Piston 4... Ultra-high pressure chamber 5... Packing case 6... Annular seal packing 7... Packing holder 8... Holding member 9... Lid block

Claims (1)

[Claims] An annular seal packing installed in the sliding part of ultra-high pressure equipment, with an inverted V-shaped or inverted U-shaped cross section, with an apex angle of θ_1 on the protruding side and an apex angle of θ_2 on the concave side. When, θ
An annular seal packing for ultra-high pressure equipment, characterized by satisfying _1>θ_2.