JP7710282B2 - Ultra-high pressure seals and reciprocating pumps - Google Patents

Description

The present invention relates to an ultra-high pressure sealing device and a reciprocating pump, and in particular to an ultra-high pressure sealing device and a reciprocating pump equipped with a packing ring having a single or multiple conductive grooves.

Conventionally, in a high-pressure pump with a pressure of 400 MPa, a sealing device is known that is configured by sequentially arranging a bottom ring, a backup ring, a packing ring, and an elastic ring in the axial direction from the low pressure section to the high pressure section.

For example, the seal device used in the high-pressure pump described in Patent Document 1 uses a high-strength stainless steel material for the bottom ring to ensure sliding characteristics with the inner member (plunger). It also includes a backup ring and an elastic ring to ensure sealing with the outer member (cylinder).

In addition, in the ultra-high pressure sealing device described in Patent Document 2, the bottom ring and backup ring are made of a copper alloy, and the bottom ring has higher tensile strength and hardness than the backup ring.

Patent No. 4123547 Patent No. 6397377

However, by improving the sealing performance to withstand ultra-high pressure (500 MPa or more), there is an increased chance that the back pressure inside the cylinder will be trapped in the gaps between the packing ring and the elastic ring, and the energy from the back pressure inside the cylinder will affect the packing ring and the elastic ring, resulting in damage to the packing ring and the elastic ring.

The present invention has been made in view of this background, and aims to provide an ultra-high pressure sealing device and a reciprocating pump that improve sealing performance at ultra-high pressures, and that can increase fluid conductivity and improve durability by forming a relief flow path using a conductive groove to reduce the effects of back pressure inside the cylinder caused by the reciprocating movement of the plunger.

The ultra-high pressure sealing device of the present invention is an ultra-high pressure sealing device that is disposed in an annular gap formed between an outer member and an inner member, and seals the annular gap to separate a high pressure chamber and a low pressure chamber, and is equipped with a bottom ring that contacts the outer member on the low pressure side to seal, a backup ring that contacts and seals the high pressure side tip of the bottom ring, a packing ring that contacts and seals the high pressure side end faces of the bottom ring and the backup ring, and an elastic ring that contacts and seals the tip of the packing ring, and the tip of the packing ring has single or multiple conductive grooves, and when the inner member moves to the high pressure side, it is part of the annular gap, and the annular space formed by the outer member, the packing ring and the elastic ring is not conductive to the conductive groove , and when the inner member moves to the low pressure side, the conductive groove is conductive to the annular space, thereby discharging fluid that has entered the annular space to the high pressure side outside the annular space .

The ultra-high pressure sealing device of the present invention improves sealing performance at ultra-high pressure, and by forming a relief flow path with a conductive groove, it is possible to increase the fluid conductivity and improve durability so that the effect of back pressure inside the cylinder caused by the reciprocating movement of the plunger is reduced. Therefore, this ultra-high pressure sealing device is particularly suitable for use in reciprocating drive pumps used in the high-pressure ultra-high pressure range (500 to 700 MPa).

FIG. 1 is a schematic cross-sectional view of a main part of an ultra-high pressure sealing device and a reciprocating pump according to an embodiment of the present invention. 1A is a perspective view showing a packing seal according to an embodiment of the present invention, in which (a) conductive grooves are uniformly arranged in the circumferential direction, (b) one conductive groove, and (c) two conductive grooves; An enlarged view of the main parts of a conventional ultra-high pressure sealing device and a reciprocating pump, showing the state when ultra-high pressure is applied. An enlarged view of the essential parts of a conventional ultra-high pressure sealing device and a reciprocating pump, showing the state when the ultra-high pressure load is released. FIG. 2 is an enlarged view of the essential parts of the ultra-high pressure sealing device and the reciprocating pump according to the embodiment of the present invention, showing the state when ultra-high pressure is applied; FIG. 2 is an enlarged view of the essential parts of the ultra-high pressure sealing device and the reciprocating pump according to the embodiment of the present invention, showing a state when the load of ultra-high pressure is removed;

An example of an ultra-high pressure sealing device and a reciprocating pump according to an embodiment of the present invention is described below.

<Ultra-high pressure sealing device>
As shown in Fig. 1, the ultra-high pressure sealing device 1 is a suitable device for sealing and preventing leakage of extremely high pressure fluids from fluid couplings such as valves and swivel joints, pumps such as reciprocating pumps and high pressure plunger pumps, and high pressure generators for pressurizing fluids, and can seal fluids with pressures of 500 MPa or more. The ultra-high pressure sealing device 1 is disposed so as to seal an annular gap C1 formed between an outer member 2 and an inner member 3, and is provided so as to seal this annular gap C1 to separate a high pressure chamber RH and a low pressure chamber RL. Hereinafter, as an example of the ultra-high pressure sealing device 1, a case where it is used in a reciprocating pump 10 (plunger pump) in which the outer member 2 is a cylinder member 20 constituting a pressure vessel and the inner member 3 is a plunger member 30 that moves back and forth within the cylinder member 20 will be described.

The ultra-high pressure sealing device 1 is composed of a bottom ring 4 fitted onto the outer periphery of the plunger member 30 near the low pressure chamber RL in the annular gap C1, a backup ring 5 fitted onto the small diameter outer periphery 4f and central outer periphery 4g of the bottom ring 4, a packing ring 6 fitted onto the outer periphery of the plunger member 30 adjacent to the bottom ring 4 near the high pressure chamber RH, an elastic ring 7 fitted onto the small diameter outer periphery 6f and central outer periphery 6g of the packing ring 6, and a spacer ring 8 loosely fitted onto the outer periphery of the plunger member 30 on the high pressure chamber RH side.

<Outer member>
1, the outer member 2 is a pressure vessel such as a cylinder member 20. The outer member 2 is a cylindrical member that forms a cylinder chamber 2a into which the inner member 3 is inserted so as to be movable forward and backward, and is disposed within a housing (not shown).

<Inner member>
The inner member 3 is a plunger member 30 (piston) that reciprocates by hydraulic pressure, etc. The inner member 3, for example, is moved backward by a valve spring (not shown) provided on the low pressure chamber RL side, thereby drawing fluid into the high pressure chamber RH and moving forward to the high pressure chamber RH side, thereby fulfilling the function of a pump that presses and discharges the high pressure fluid in the high pressure chamber RH.

<Annular gap>
The annular gap C1 is a space that is formed between the plunger member 30 and the cylinder member 20 and has a cylindrical shape in a vertical cross section, and is an installation space in which packing members (sealing members) such as a packing ring 6 and an elastic ring 7 are disposed. A bottom ring 4, a backup ring 5, a packing ring 6, an elastic ring 7, and a spacer ring 8 are inserted into the annular gap C1 in this order from the low pressure chamber RL side toward the low pressure side of the high pressure chamber RH, and are sealed to separate the high pressure chamber RH side from the low pressure chamber RL side, thereby preventing the high pressure fluid from leaking to the outside.

<Bottom ring>
The bottom ring 4 is a substantially cylindrical member having greater rigidity than the backup ring 5, the packing ring 6, and the elastic ring 7. The bottom ring 4 is composed of an inner peripheral portion 4a that contacts the plunger member 30 (inner member 3), a large-diameter outer peripheral portion 4e that is connected to the low-pressure chamber side end surface portion 4b and contacts the cylinder member 20 (outer member 2), a small-diameter outer peripheral portion 4f that is smaller in diameter than the large-diameter outer peripheral portion 4e and connects to the high-pressure chamber side end surface portion 4c, and a central outer peripheral portion 4g that is formed so that the outer peripheral portion 4d is connected to the large-diameter outer peripheral portion 4e and the small-diameter outer peripheral portion 4f. The tip portion 4A of the bottom ring 4 is a protrusion with a reduced diameter.

The bottom ring 4 is fitted into the opening on the low pressure chamber RL side of the cylinder chamber 2a of the cylinder member 20.

The inner peripheral portion 4a is formed closest to the axis of the bottom ring 4 and is the bearing portion of the plunger member 30 against which the outer peripheral surface of the plunger member 30 abuts.

The low pressure chamber side end surface portion 4b is a flat annular end surface in side view formed on the low pressure chamber RL side of the substantially cylindrical bottom ring 4.

The high-pressure chamber side end surface 4c is an annular end surface formed on the high-pressure chamber RH side of the bottom ring 4. This high-pressure chamber side end surface 4c is positioned in contact with a portion of the low-pressure chamber side end surface 6b of the packing ring 6 near the axis.

The outer periphery 4d is a cylindrical outer periphery of the bottom ring 4, and is formed in a stepped shape by the large diameter outer periphery 4e, the small diameter outer periphery 4f, and the central outer periphery 4g described below. The large diameter outer periphery 4e is the outer periphery of the large diameter that is formed with the largest outer diameter in the outer periphery 4d, and is formed in a cylindrical shape in a part closer to the low pressure chamber RL. The large diameter outer periphery 4e is disposed in a state where it abuts against the inner wall of the cylinder chamber 2a of the cylinder member 20. The outer diameter of the large diameter outer periphery 4e of the bottom ring 4, the outer diameter of the outer periphery 5c of the backup ring 5, the outer diameter of the large diameter outer periphery 6e of the packing ring 6, the outer diameter of the outer periphery 7c of the elastic ring 7, and the outer diameter of the inner periphery 8b of the spacer ring 8 are approximately the same.

The small diameter outer peripheral portion 4f is the smallest diameter peripheral surface in the outer peripheral portion 4d, and is formed cylindrically in the portion closest to the high pressure chamber RH. The small diameter outer peripheral portion 4f is disposed in contact with the inner wall of the inner peripheral portion 5a of the backup ring 5. The small diameter outer peripheral portion 4f and the inner peripheral portion 5a, which are in contact with each other, are disposed parallel to the inner wall surface of the cylinder chamber 2a and the outer peripheral surface of the plunger member 30.

The bottom ring 4 and the backup ring 5 are fitted together at a small diameter outer periphery 4f and inner periphery 5a, which are not tapered, to ensure concentricity. The non-tapered, vertical high pressure chamber side end face 4c and high pressure chamber side end face 5e of the bottom ring 4 and backup ring 5 abut against the low pressure chamber side end face 6b of the packing ring 6, ensuring perpendicularity and concentricity, supporting the plunger member 30 so that it does not wobble, and improving fluid leakage and packing life.

The central outer periphery 4g is a side portion (outer periphery portion) that has a tapered shape that connects the large diameter outer periphery 4e to the small diameter outer periphery 4f of the bottom ring 4. The central outer periphery 4g is disposed in a state in which the locking portion 5b of the backup ring 5 abuts against the central periphery portion 4g, and an annular gap C2 is formed in the portion near the outer periphery.

The annular gap C2 is a sealed annular space that is triangular in cross section and is formed between the central outer periphery 4g of the bottom ring 4, the gap-forming end face 5d of the backup ring 5, and the inner wall of the cylinder chamber 2a of the cylinder member 20. The annular gap C2 is formed in a portion near the outer periphery of the central outer periphery 4g, which is formed in an inclined shape in cross section, and serves to enhance the wedge effect of the backup ring 5.

<Backup ring>
The backup ring 5 is a wedge-shaped ring member that is a pentagon (a polygon having five sides) in a vertical cross section, and is fitted onto the small diameter outer periphery 4f and the central outer periphery 4g of the bottom ring 4. The high pressure chamber RH side of the bottom ring 4 is arranged in a state of being divided into two parts, a small diameter part of the bottom ring 4 on the plunger member 30 side, and the backup ring 5 on the cylinder member 20 (outer member 2) side, in a vertical cross section. The backup ring 5 is composed of an inner periphery 5a that is fitted onto the small diameter outer periphery 4f of the bottom ring 4 and abuts against the small diameter outer periphery 4f, a locking part 5b that is locked to the central outer periphery 4g of the bottom ring 4 so that axial movement is restricted, an outer periphery 5c that abuts against the cylinder member 20, a gap forming end face 5d formed at a position facing the annular gap C2, and a high pressure chamber side end face part 5e that abuts against the packing ring 6.

The inner peripheral portion 5a is the inner surface on the axial center side (plunger member 30 side) of the ring-shaped backup ring 5, and is fitted onto the small diameter outer peripheral portion 4f formed on the high pressure chamber RH side of the bottom ring 4. The locking portion 5b has a tapered shape that matches the tapered shape of the bottom ring 4, and is formed with a diameter that expands from the low pressure chamber side end of the inner peripheral portion 5a toward the outer peripheral portion. The locking portion 5b is arranged by fitting onto the central outer peripheral portion 4g of the bottom ring 4 near the axial center, and forms part of the inner peripheral portion 5a of the backup ring 5.

The outer peripheral portion 5c is the outer surface of the outer peripheral side (the cylinder chamber 2a side of the cylinder member 20) of the ring-shaped backup ring 5, and is disposed in contact with the inner wall of the cylinder chamber 2a. The gap forming end surface 5d is the outer peripheral side portion of the low pressure chamber side end of the backup ring 5, and is formed with a reduced diameter from the low pressure chamber side end of the outer peripheral portion 5c to the outer peripheral side end of the locking portion 5b. Therefore, the gap forming end surface 5d constitutes a part of the outer peripheral portion 5c.

The high pressure chamber side end surface 5e is the high pressure chamber side end surface of the backup ring 5, and is arranged in contact with the outer peripheral portion of the low pressure chamber side end surface 6b of the packing ring 6. The high pressure chamber side end surface 5e of the backup ring 5 and the high pressure chamber side end surface 4c of the bottom ring 4 are formed on the same plane perpendicular to the axial direction (the outer peripheral surface of the plunger member 30) and are arranged in a straight line when viewed in vertical section in order to prevent the packing ring 6 from being biased or tilted.

<Packing ring>
The packing ring 6 is a substantially cylindrical member interposed between the bottom ring 4, the backup ring 5, and the spacer ring 8 in the annular gap C1. The packing ring 6 is composed of a low pressure chamber side end surface portion 6b that abuts against the high pressure chamber side end surface portion 5e of the backup ring 5, an inner peripheral portion 6a that abuts against the plunger member 30, a large diameter outer peripheral portion 6e that is connected to the low pressure chamber side end surface portion 6b and abuts against the cylinder member 20, a small diameter outer peripheral portion 6f that is reduced in diameter from the large diameter outer peripheral portion 6e and is connected to the high pressure chamber side end surface portion 6c, and a central outer peripheral portion 6g that is formed so that the outer peripheral portion 6d is connected to the large diameter outer peripheral portion 6e and the small diameter outer peripheral portion 6f. The packing ring 6 is made of a synthetic resin such as high molecular weight polyethylene. The tip portion 6A of the packing ring 6 is a projection with a reduced diameter.

The inner peripheral portion 6a is formed closest to the axial line of the packing ring 6 and is a sealing portion against which the outer peripheral surface 3a of the plunger member 30 abuts.
The low pressure chamber side end surface 6b is a portion disposed in contact with the high pressure chamber side end surface 5e of the backup ring 5 and the high pressure chamber side end surface 4c of the bottom ring 4. This low pressure chamber side end surface 6b is formed perpendicular to the axial direction (the sliding direction of the plunger member 30), thereby maintaining the shape of the vertical surface of the packing ring 6 and the concentric position of the packing ring 6.

The high-pressure chamber side end surface portion 6c is a vertical end surface formed on the high-pressure chamber RH side of the packing ring 6 in a longitudinal section, and is formed in an annular shape in a side view. When no load a is applied to the spacer ring 8 in the direction of the low pressure chamber RL, the high-pressure chamber side end surface portion 6c is positioned in a state in which it is spaced apart from the low-pressure chamber side end surface portion 8c of the spacer ring 8. When a load a is applied to the spacer ring 8 in the direction of the low pressure chamber RL, the high-pressure chamber side end surface portion 6c is pressed against the low-pressure chamber side end surface portion 8c of the spacer ring 8, compressing the packing ring 6.

The outer periphery 6d is the cylindrical outer periphery of the packing ring 6, and is formed in a stepped shape by the large diameter outer periphery 6e, the small diameter outer periphery 6f, and the central outer periphery 6g.

The large diameter outer peripheral portion 6e is the outer peripheral surface of the outer peripheral portion 6d that has the largest outer diameter, and is formed in a parallel cylindrical shape along the outer peripheral surface of the plunger member 30 at a location closer to the low pressure chamber RL. This large diameter outer peripheral portion 6e is arranged in a state in which it abuts against the inner wall of the cylinder chamber 2a of the cylinder member 20. The large diameter outer peripheral portion 6e is interposed between the backup ring 5 and the elastic ring 7, and is arranged at a distance such that the backup ring 5 and the elastic ring 7 do not abut against each other.

The small diameter outer periphery 6f is a peripheral surface of the outer periphery 6d that is smaller in diameter than the large diameter outer periphery 6e, and is formed in a cylindrical shape at a portion closer to the high pressure chamber RH. The small diameter outer periphery 6f is disposed in a state in which it abuts against the inner wall of the inner periphery 7a of the annular elastic ring 7, and is disposed in a state in which it does not abut against the cylinder member 20.

The central outer periphery 6g is a side portion that has a tapered shape that connects the large diameter outer periphery 6e to the small diameter outer periphery 6f of the packing ring 6. The central outer periphery 6g is disposed in a state in which the locking portion 7b of the packing ring 6 abuts against the central periphery 6g at the portion on the axial center side, and an annular gap (annular space) C3 is formed in the portion near the outer periphery.

The annular gap (annular space) C3 is a sealed space that is a right-angled triangle in vertical cross section and is formed between the central outer periphery 6g of the packing ring 6, the gap-forming end face 7d of the elastic ring 7, and the inner wall of the cylinder chamber 2a. The annular gap (annular space) C3 is formed in a portion near the outer periphery of the central outer periphery 6g, which is formed in an inclined shape in vertical cross section, and thus enhances the wedge effect of the elastic ring 7 and fulfills its role.

The conductive groove 6i is a groove formed in the tip portion 6A of the packing ring 6, as shown in Figures 1 and 2. When the inner member 3 moves to the high-pressure side, the conductive groove 6i is not conductive to the annular gap (annular space) C3 formed by the outer member 2, the packing ring 6, and the elastic ring 7, but is conductive to the annular gap (annular space) C3 when the inner member 3 moves to the low-pressure side.

Even if the inner member 3 repeatedly moves back and forth, the fluid that penetrates into the annular gap (annular space) C3 is discharged from the conductive groove 6i, which functions as a relief flow path, to the outside of the annular gap (annular space) C3, preventing the annular gap (annular space) from becoming pressurized (reducing the adverse effects of back pressure), and preventing damage to the outer member 2, packing ring 6, and elastic ring 7 that constitute the annular gap (annular space) C3.

As shown in FIG. 2(a), one or more conductive grooves 6i can be formed, but by arranging multiple grooves evenly around the circumferential direction of the tip portion 6A of the packing ring 6, the back pressure inside the cylinder (confined in the annular gap (annular space) C3) can be uniformly distributed.

Because the conductive groove 6i is a place through which fluid passes, a conductive groove protective part 6ib can be arranged to provide additional protection against damage, etc. The conductive groove protective part 6ib may be anything that can be connected to the conductive groove 6i. Instead of the conductive groove protective part 6ib, it is also conceivable to coat the surface of the tip part 6A of the packing ring 6.

The conductive grooves 6i need only function to provide electrical continuity in association with the movement of the inner member 3, and as shown in Figures 2(b) and (c), it goes without saying that the number of conductive grooves 6i can be changed as appropriate, as can their height, width, depth, shape, etc.

The conductive groove 6i can also have a width L2 that is longer than the width L1 of the tip 6A of the packing ring 6. Although the elastic ring 7 repeatedly contracts and expands due to the energy generated by the movement of the inner member 7, the error is extremely small, so if the width of the conductive groove 6i is too short, the discharge of the fluid in the annular gap (annular space) C3, which is the purpose of forming the conductive groove 6i, will not function (as a relief circuit), so by forming the width L2 of the conductive groove 6i to be longer than the width L1 of the tip 6A of the packing ring 6, water conductivity can be reliably obtained.

As shown in FIG. 3, in the case of an ultra-high pressure sealing device in which the conductive groove 6i is not formed and ultra-high pressure is applied, forces are applied to the elastic ring 7 in the directions of arrows c and d, and the outer member 2 and packing ring 6 are in close contact with each other. At this time, the area within the annular gap (annular space) C3 becomes smaller than before the ultra-high pressure was applied, and pressure is trapped inside.

Also, as shown in Figure 4, in the case of the ultra-high pressure sealing device in a state where the load of ultra-high pressure is released, forces are applied to the elastic ring 7 in the directions of arrows ca and da, and the outer member 2 and the tip 6a of the packing ring 6 are in close contact with each other. At this time, the area within the annular gap (annular space) C3 is also affected by the reaction caused by the load of ultra-high pressure, and becomes larger than before the ultra-high pressure was applied, and the back pressure is relaxed.

The reciprocating pump generates high-pressure fluid by reciprocating the internal member 3, so it is again in the state shown in Figure 3 when ultra-high pressure is applied. However, even if each element is sealed, it is difficult to 100% prevent fluid from entering. Fluid will remain in the annular gap (annular space) C3, and after further infiltration, the area of the annular gap (annular space) C3 will become smaller again. As a result, the back pressure of the annular gap (annular space) C3 will induce damage to the outer member 2, packing ring 6, and elastic ring 7 that make up the annular gap (annular space) C3.

Therefore, in the ultra-high pressure sealing device of the present invention, by forming the conductive groove 6i, it is possible to prevent excessive back pressure from being trapped in the annular gap (annular space) C3.
The state in which ultra-high pressure is applied as shown in Figure 5 has the same basic principle as the energy and fluid movement in Figures 3 and 4. The difference is the mechanism in the state in which the ultra-high pressure load is released as shown in Figure 6.

Forces are applied to the elastic ring 7 in the directions of the arrows ca and da, causing it to come into close contact with the outer member 2 and the tip 6a of the packing ring 6; however, by forming the water guide groove 6i, the fluid that has entered the annular gap (annular space) C3 is discharged in the direction of S1, so that even if ultra-high pressure is applied again, back pressure is not trapped inside the annular gap (annular space) C3, and damage to the outer member 2, packing ring 6, and elastic ring 7 that make up the annular gap (annular space) C3 can be suppressed.

<Elastic ring>
The elastic ring 7 is an annular member having a pentagonal shape (a polygon having five sides) in a vertical cross section. The elastic ring 7 is composed of an inner peripheral portion 7a that is fitted onto the small-diameter outer peripheral portion 6f of the packing ring 6 and abuts against the small-diameter outer peripheral portion 6f, a locking portion 7b that is locked to the central outer peripheral portion 6g of the packing ring 6 so as to restrict axial movement, an outer peripheral portion 7c that abuts against the cylinder member 20, a gap forming end face 7d formed at a position facing the annular gap (annular space) C3, and a high-pressure chamber side end face portion 7e that abuts against the spacer ring 8.

The elastic ring 7 is fitted onto the small diameter outer periphery 6f and the central outer periphery 6g of the packing ring 6 and is arranged in a state of being pressed against the spacer ring 8, so that it is arranged to be compressed and tightly attached between the cylinder member 20 and the tapered central outer periphery 6g. Therefore, the elastic ring 7 presses the packing ring 6 toward the plunger member 30 side (arrow b direction). As a result, the inner periphery 7a and the locking portion 7b of the elastic ring 7 are tightly attached to the small diameter outer periphery 6f and the central outer periphery 6g of the packing ring 6, the outer periphery 7c is tightly attached to the inner wall surface of the cylinder chamber 2a, and the inner periphery 6a of the packing ring 6 is tightly attached to the outer periphery surface of the plunger member 30, so that an initial pressure is obtained between each member. The elastic ring 7 is, for example, a synthetic rubber having elasticity such as urethane rubber.

The inner peripheral portion 7a is the inner surface on the axial side of the ring-shaped elastic ring 7, and is fitted onto the small-diameter outer peripheral portion 6f of the packing ring 6. The locking portion 7b has a tapered shape that matches the tapered shape of the packing ring 6, and is formed with a diameter that expands from the low-pressure chamber side end of the inner peripheral portion 7a toward the outer peripheral portion. The locking portion 7b is fitted onto the central outer peripheral portion 6g of the packing ring 6 near the axial center, and forms part of the inner peripheral portion 7a of the elastic ring 7.

The outer peripheral portion 7c is the outer surface of the outer periphery of the ring-shaped elastic ring 7, and is arranged in contact with the inner wall of the cylinder chamber 2a. The gap forming end surface 7d is the outer peripheral portion of the low pressure chamber side end of the elastic ring 7, and is formed vertically from the low pressure chamber side end of the outer peripheral portion 7c to the outer peripheral side end of the locking portion 7b.

The high-pressure chamber side end surface 7e is the end surface of the elastic ring 7 on the high-pressure chamber RH side, and is arranged in a state where the outer peripheral end of the low-pressure chamber side end surface 8c of the spacer ring 8 abuts against it when no load a is applied to the spacer ring 8 in the direction of the low-pressure chamber RL. In other words, the high-pressure chamber side end surface 7 of the elastic ring 7 is tapered so that the diameter decreases from the high-pressure chamber RH side to the low-pressure chamber RL side from the end on the outer peripheral portion 7c side to the end on the inner peripheral portion 7a side in the axial direction. When a load a is applied to the spacer ring 8 in the direction of the low-pressure chamber RL, the entire end surface of the low-pressure chamber side end surface 8c of the spacer ring 8 is pressed against the high-pressure chamber side end surface 7e, compressing the elastic ring 7.

<Spacer ring>
The spacer ring 8 is a metallic cylindrical member fitted into the inner wall of the cylinder chamber 2a in a state in which it abuts against the outer circumferential end of the high-pressure chamber side end face 7e of the elastic ring 7 within the high-pressure chamber RH. As shown in Fig. 1, the spacer ring 8 is composed of an outer circumferential portion 8a into which the plunger member 30 is inserted and arranged so as to be movable back and forth, an inner circumferential portion 8b fitted into the inner wall surface of the cylinder chamber 2a, and a low-pressure chamber side end face portion 8c arranged opposite the high-pressure chamber side end face portion 6c of the packing ring 6 and the high-pressure chamber side end face portion 7e of the elastic ring 7.

The spacer ring 8 can also have a water guide groove 8d on the low pressure end face. By forming the water guide groove 8d, the number of water guide points increases, and the fluid in the annular space C is prevented from becoming trapped, reducing damage to the packing ring 6 and the elastic ring 7. As shown in Figure 6, the fluid can escape in the direction of S2.

The spacer ring 8 can also have a central water guide groove (hole) 8e in the center. By forming the central water guide groove 8e, the fluid in the annular gap C is prevented from becoming trapped, reducing damage to the packing ring 6 and the elastic ring 7. As shown in FIG. 6, the fluid can escape in the direction of S3.

Although the water conduction provided by the central water guide groove (hole) 8e is sufficient, water guide groove 8d is located on the low pressure side of spacer ring 8 and is more likely to come into contact with packing ring 6 and elastic ring 7, and therefore is more likely to have a greater effect (reduce damage).
The height, width, depth, shape, number, etc. of the water guiding groove 8d and the central water guiding groove (hole) 8e can be changed as appropriate.

≪Effect≫
The operation of the ultra-high pressure sealing device 1 and the reciprocating pump 10 according to the embodiment of the present invention will be described.

The reciprocating pump 10 is arranged so that the elastic ring 7 abutting against the spacer ring 8 is compressed on the high pressure chamber RH side of the packing ring 6. This allows pressure in the direction of the high pressure chamber RH to be transmitted to the backup ring 5 and bottom ring 4 via the packing ring 6, resulting in tight contact between these components with no gaps, making it possible to obtain an appropriate initial pressure between each sealing component.

When a load is applied from the high pressure chamber RH side to the low pressure chamber RL side (arrow a direction) of the reciprocating pump 10, the elastic ring 7 and the packing ring 6 are pushed toward the low pressure chamber RL side, compressing them. The elastic ring 7 is compressed and moves toward the low pressure chamber RL as a whole, and the locking portion 7b moves along the tapered surface of the central outer periphery 6g, and the outer periphery 7c is pressed against the inner wall surface of the cylinder chamber 2a to seal in close contact. The locking portion 7b also pushes the central outer periphery 6g of the packing ring 6 in the axial direction (arrow b direction), and the inner periphery 6a is pressed against the plunger member 30 to seal. The packing ring 6 presses the high pressure chamber side end surface portions 5e, 4c of the backup ring 5 and the bottom ring 4.

The low pressure chamber side end surface 6b of the packing ring 6 abuts against the high pressure chamber side end surface 5e of the backup ring 5 and the high pressure chamber side end surface 4c of the bottom ring 4, so that the ultra-high pressure axial pressing force (direction of arrow e) transmitted from the packing ring 6 can be transmitted simultaneously to both the backup ring 5 and the bottom ring 4. This allows the backup ring 5 to quickly seal against the inner wall surface of the cylinder chamber 2a and the bottom ring 4 to quickly seal against the plunger member 30, improving sealing performance.

The backup ring 5 is fitted onto the small diameter outer periphery 4f of the bottom ring 4, so that the ultra-high pressure axial (arrow e) pressing force transmitted from the packing ring 6 can be shared between the backup ring 5 and the bottom ring 4. In addition, the small diameter outer periphery 4f of the bottom ring 4, on which the backup ring 5 is fitted, ensures the concentricity of the bottom ring 4 and the backup ring 5, so that the outer periphery 6d of the packing ring 6 can be properly brought into close contact with the inner wall surface of the cylinder chamber 2a.

The backup ring 5 has an outer periphery 5c that is expanded in the outer periphery direction (arrow g direction) pressed against the inner wall surface of the cylinder chamber 2a to make a tight seal, improving the sealing performance with the inner wall surface of the cylinder chamber 2a. In addition, the wedge-shaped locking portion 5b of the backup ring 5 presses the inner periphery 4a of the bottom ring 4 on the axial side in the axial direction (arrow f direction) to make a tight seal with the outer periphery surface of the plunger member 30.

As a result, the inner periphery 4a of the bottom ring 4 can significantly improve the sliding characteristics, sealing performance, durability, and seal life while ensuring sealing performance against the plunger member 30 under ultra-high pressure conditions, making it possible to seal even ultra-high pressure fluids of 500 MPa or more.

In the above embodiment, the ultra-high pressure sealing device 1 for use at ultra-high pressures has been described, but it is not limited to this and can be similarly applied to various parts at pressures lower than ultra-high pressures (500 MPa or more).

REFERENCE SIGNS LIST 1 Ultra-high pressure sealing device 2 Outer member 3 Inner member 4 Bottom ring 4a, 5a, 6a, 7a Inner periphery 4b, 6b Low pressure chamber side end face 4c, 5e, 6c High pressure chamber side end face 4d, 5c, 6d, 7c Outer periphery 4e, 6e Large diameter outer periphery 4f, 6f Small diameter outer periphery 4g, 6g Central outer periphery 6i Conducting groove 5 Backup ring 5b, 7b Locking portion 6 Packing ring 7 Elastic ring 8 Spacer ring 8d Water guide groove 8e Central water guide groove 10 Reciprocating drive pump 20 Cylinder member 30 Plunger member C Annular gap RH High pressure chamber RL Low pressure chamber

Claims (7)

An ultra-high pressure sealing device that is disposed in an annular gap formed between an outer member and an inner member and seals the annular gap to separate a high pressure chamber and a low pressure chamber,
a bottom ring that contacts and seals with the outer member on the low pressure side;
a backup ring that contacts and seals a tip end portion of the bottom ring on the high pressure side ;
a packing ring that contacts and seals the bottom ring and the high pressure side end surface of the backup ring;
an elastic ring that contacts and seals the tip of the packing ring;
The tip of the packing ring has a single or multiple conductive grooves,
When the inner member moves to the high pressure side, a part of the annular gap, an annular space formed by the outer member, the packing ring and the elastic ring, is not electrically connected to the conductive groove ,
An ultra-high pressure sealing device in which, when the inner member moves to the low pressure side, the conductive groove becomes conductive with the annular space, thereby discharging fluid that has entered the annular space to the high pressure side outside the annular space . The ultra-high pressure sealing device according to claim 1, wherein the conductive grooves are arranged evenly around the circumferential edge of the packing ring. 3. The ultra-high pressure sealing device according to claim 1, wherein the conductive groove has a width greater than a width of the tip end of the packing ring in the axial direction . The ultra-high pressure sealing device according to any one of claims 1 to 3, further comprising a conductive groove protection part for protecting the conductive groove. a spacer ring sealing against the high pressure side of the elastic ring;
5. The ultra-high pressure sealing device according to claim 1, wherein the spacer ring has a water guide groove on an end surface on the low pressure side. a spacer ring sealing against the high pressure side of the elastic ring;
6. The ultra-high pressure sealing device according to claim 1, wherein the spacer ring has a central water guide groove at a central portion in the direction of the axis of the spacer ring . A reciprocating pump having a pressure of 500 MPa or more, comprising the ultra-high pressure sealing device according to any one of claims 1 to 6,
the outer member is a cylinder member;
The reciprocating drive pump according to claim 1, wherein the inner member is a plunger member.