Ultra-high pressure sealing device and reciprocating drive pump

Abstract

To provide an ultrahigh-pressure sealing device which can improve sealing performance at ultrahigh pressure, can enhance the water conveyance performance of fluid so as to reduce an influence of backpressure generated by the reciprocation of a plunger by forming a relief flow passage by conductive grooves, and can improve durability, and a reciprocation pump.SOLUTION: An ultrahigh-pressure sealing device of the present invention comprises a bottom ring for sealing an outside member while contacting therewith at a low-pressure side, a backup ring for sealing a tip part of the bottom ring while contacting therewith, a packing ring for sealing a high-pressure end parts of the bottom ring and the backup ring while contacting therewith, and an elastic ring for sealing a tip part of the packing ring while contacting therewith. The tip part of the packing ring has a single or a plurality of conductive grooves, and when an inside member moves to a high-pressure side, the outside member does not conduct with an annular space which is formed of the packing ring and the elastic ring, and when the inside member moves to the low-pressure side, the outside member conducts with the annular space.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ultra-high pressure sealing device and a reciprocating drive pump, and particularly to an ultra-high pressure sealing device and a reciprocating drive pump provided with a packing ring having one or more conduction grooves.

Background Art

[0002] Conventionally, in a high-pressure pump where the pressure reaches 400 MPa, a sealing device 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 part to the high-pressure part is known.

[0003] For example, in the sealing device used in the high-pressure pump described in Patent Document 1, a stainless steel member with high strength is adopted for the bottom ring in order to ensure the sliding characteristics with the inner member (plunger). Also, a backup ring and an elastic ring are provided to ensure the sealing property with the outer member (cylinder).

[0004] In addition, in the ultra-high pressure sealing device described in Patent Document 2, the bottom ring and the backup ring are made of a copper alloy, and the bottom ring has higher tensile strength and hardness than the backup ring.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, by improving the sealing performance so as to withstand ultra-high pressure (500 MPa or more), conversely, the chance that the back pressure inside the cylinder accumulates in the gaps between the packing ring and the elastic ring increases, and the energy due to the back pressure inside the cylinder affects the packing ring and the elastic ring. As a result, there has been a problem that the packing ring and the elastic ring are damaged.

[0007] The present invention has been made in view of such a background, and while improving the sealing performance at ultra-high pressure, by forming a relief flow path by a conduction groove, the influence of the back pressure inside the cylinder due to the reciprocating movement of the plunger is reduced. An object of the present invention is to provide an ultra-high pressure sealing device and a reciprocating drive pump that can enhance the water conductivity of a fluid and improve durability.

Means for Solving the Problems

[0008] The ultra-high pressure sealing device of the present invention is disposed in an annular gap formed between an outer member and an inner member, and is an ultra-high pressure sealing device that seals the annular gap and partitions 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, and the on the high-pressure side A backup ring that contacts and seals with the tip of the bottom ring, a packing ring that contacts and seals with the high-pressure side end faces of the bottom ring and the backup ring, and an elastic ring that contacts and seals with the tip of the packing ring. The tip of the packing ring has a single or a plurality of conduction grooves. When the inner member moves to the high-pressure side, it is a part of the annular gap and does not communicate with the annular space formed by the outer member, the packing ring, and the elastic ring. When the inner member moves to the low-pressure side, the conduction groove and It communicates with the annular space the conduction groove discharges the fluid that has entered the annular space to the high-pressure side outside the annular space .

Effects of the Invention

[0009] The ultra-high pressure sealing device according to the present invention improves the sealing performance at ultra-high pressure, and by forming a relief flow path through the conduction groove, it enhances the water conductivity of the fluid so that the influence of the back pressure inside the cylinder due to the reciprocating movement of the plunger is reduced, and the durability can be improved. Therefore, this ultra-high pressure sealing device can be suitably used especially for a reciprocating drive pump used in an ultra-high pressure region (500 to 700 MPa) with high pressure.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] An example of the ultra-high pressure sealing device and the reciprocating drive pump according to the embodiment of the present invention will be described.

[0012] ≪Ultra-high pressure sealing device≫ As shown in Fig. 1, the ultra-high pressure sealing device 1 is a device suitable for sealing very high-pressure fluids such as fluid joints like valves and swivel joints, pumps such as reciprocating drive pumps and high-pressure plunger pumps, and high-pressure generating devices for pressurizing fluids, and can seal fluids with a pressure of 500 MPa or more. The ultra-high pressure sealing device 1 is arranged to seal an annular gap C1 formed between an outer member 2 and an inner member 3, and is provided to seal this annular gap C1 to partition a high-pressure chamber RH and a low-pressure chamber RL. Hereinafter, as an example of the ultra-high pressure sealing device 1, the case where the outer member 2 is configured as a cylinder member 20 constituting a pressure vessel and the inner member 3 is configured as a plunger member 30 that reciprocates in the cylinder member 20 and is used in a reciprocating drive pump 10 (plunger pump) will be described as an example.

[0013] In the ultra-high pressure sealing device 1, in the annular gap C1, a bottom ring 4 externally fitted to the outer peripheral portion of the plunger member 30 near the low-pressure chamber RL, backup rings 5 externally fitted to the small-diameter outer peripheral portion 4f and the central outer peripheral portion 4g of the bottom ring 4, a packing ring 6 externally fitted to a position adjacent to the bottom ring 4 on the outer peripheral surface of the plunger member 30 near the high-pressure chamber RH, elastic rings 7 externally fitted to the small-diameter outer peripheral portion 6f and the central outer peripheral portion 6g of the packing ring 6, and a spacer ring 8 loosely fitted to the outer peripheral portion of the plunger member 30 on the high-pressure chamber RH side are provided.

[0014] <Outer member> As shown in Fig. 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 able to move forward and backward, and is installed inside a housing (not shown).

[0015] <Inner member> The inner member 3 is a plunger member 30 (piston) that reciprocates by hydraulic pressure or the like. The inner member 3, for example, retreats by a valve spring (not shown) provided on the low-pressure chamber RL side to suck fluid into the high-pressure chamber RH and move forward to the high-pressure chamber RH side, thereby performing the function of a pump that presses and discharges the high-pressure fluid in the high-pressure chamber RH.

[0016] <Annular gap> The annular gap C1 is a cylindrical space formed between the plunger member 30 and the cylinder member 20 in a longitudinal sectional view, and is an installation space in which packing members (sealing members) such as a packing ring 6 and an elastic ring 7 are arranged. Inside the annular gap C1, in order from the low-pressure chamber RL side toward the low-pressure side of the high-pressure chamber RH, a bottom ring 4, a backup ring 5, a packing ring 6, an elastic ring 7, and a spacer ring 8 are inserted and sealed so as to partition the high-pressure chamber RH side and the low-pressure chamber RL side, and are configured so that high-pressure fluid does not leak to the outside.

[0017] <Bottom ring> The bottom ring 4 is a substantially cylindrical member having higher rigidity than the backup ring 5, the packing ring 6, and the elastic ring 7. The bottom ring 4 includes an inner peripheral portion 4a that abuts against the plunger member 30 (inner member 3), a large-diameter outer peripheral portion 4e that is connected to the low-pressure chamber side end face portion 4b and abuts against the cylinder member 20 (outer member 2), a small-diameter outer peripheral portion 4f that is reduced in diameter from this large-diameter outer peripheral portion 4e and is connected to the high-pressure chamber side end face portion 4c, and a central outer peripheral portion 4g formed such 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 reduced-diameter protrusion.

[0018] The bottom ring 4 is disposed to be fitted inside the opening on the low-pressure chamber RL side of the cylinder chamber 2a of the cylinder member 20.

[0019] The inner peripheral portion 4a is formed on the bottom ring 4 to be closest to the axis line side and is a bearing portion of the plunger member 30 where the outer peripheral surface of the plunger member 30 abuts.

[0020] The low-pressure chamber side end face portion 4b is a flat annular end face formed on the low-pressure chamber RL side of the substantially cylindrical bottom ring 4 in a side view.

[0021] The high-pressure chamber side end face portion 4c is an annular end face formed on the high-pressure chamber RH side of the bottom ring 4. This high-pressure chamber side end face portion 4c is disposed in a state of abutting against a portion closer to the axis of the low-pressure chamber side end face portion 6b of the packing ring 6.

[0022] The outer peripheral portion 4d is the cylindrical outer peripheral surface of the bottom ring 4, and is formed in a stepped shape by a large-diameter outer peripheral portion 4e, a small-diameter outer peripheral portion 4f, and a central outer peripheral portion 4g, which will be described later. The large-diameter outer peripheral portion 4e is the large-diameter outer peripheral surface formed with the largest outer diameter in the outer peripheral portion 4d, and is formed in a cylindrical shape at a portion closer to the low-pressure chamber RL. The inner wall of the cylinder chamber 2a of the cylinder member 20 is disposed in contact with the large-diameter outer peripheral portion 4e. The outer diameters of the large-diameter outer peripheral portion 4e of the bottom ring 4, the outer peripheral portion 5c of the backup ring 5, the large-diameter outer peripheral portion 6e of the packing ring 6, the outer peripheral portion 7c of the elastic ring 7, and the outer diameter of the inner peripheral portion 8b of the spacer ring 8 are substantially the same.

[0023] The small-diameter outer peripheral portion 4f is the peripheral surface with the smallest diameter in the outer peripheral portion 4d, and is formed in a cylindrical shape at a portion closer to the high-pressure chamber RH. The inner wall of the inner peripheral portion 5a of the backup ring 5 is disposed in contact with the small-diameter outer peripheral portion 4f. The mutually contacting small-diameter outer peripheral portion 4f and inner peripheral portion 5a are arranged parallel to the inner wall surface of the cylinder chamber 2a and the outer peripheral surface of the plunger member 30.

[0024] The bottom ring 4 and the backup ring 5 ensure coaxiality by forming the small-diameter outer peripheral portion 4f and the inner peripheral portion 5a, which are non-tapered fitting portions. The non-tapered vertical high-pressure chamber side end face portions 4c and high-pressure chamber side end face portions 5e of the bottom ring 4 and the backup ring 5 are in contact with the low-pressure chamber side end face portion 6b of the packing ring 6, thereby ensuring a right angle and coaxiality, axially supporting the concentricity of the plunger member 30 so as not to wobble, and improving fluid leakage and the life of the packing.

[0025] The central outer peripheral portion 4g is a side surface portion (outer peripheral portion) having a tapered shape connecting the large-diameter outer peripheral portion 4e to the small-diameter outer peripheral portion 4f of the bottom ring 4. The locking portion 5b of the backup ring 5 is disposed in contact with the central outer peripheral portion 4g at a portion on the axial center side, and an annular gap C2 is formed at a portion closer to the outer periphery.

[0026] The annular gap C2 is a sealed annular space in the shape of a triangle in a longitudinal sectional view, formed between the central outer peripheral portion 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 at a portion near the outer periphery of the central outer peripheral portion 4g that is formed in an inclined shape in a longitudinal sectional view, thereby serving to enhance the wedge effect of the backup ring 5.

[0027] <Backup ring> The backup ring 5 is a wedge-shaped ring member in the shape of a pentagon (a polygon having five sides) in a longitudinal sectional view, and is externally fitted to the small-diameter outer peripheral portion 4f and the central outer peripheral portion 4g of the bottom ring 4. The high-pressure chamber RH side of the bottom ring 4 is arranged in a split state in a longitudinal sectional view, with the small-diameter portion 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. The backup ring 5 includes an inner peripheral portion 5a that is externally fitted to and abuts against the small-diameter outer peripheral portion 4f of the bottom ring 4, a locking portion 5b that is locked to the central outer peripheral portion 4g of the bottom ring 4 so as to restrict axial movement, an outer peripheral portion 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 portion 5e that abuts against the packing ring 6.

[0028] 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 externally fitted to 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 conforms to the tapered shape of the bottom ring 4, and is formed to have an increasing diameter from the low-pressure chamber side end of the inner peripheral portion 5a toward the outer peripheral portion. The locking portion 5b is externally fitted and arranged at a portion near the axial center of the central outer peripheral portion 4g of the bottom ring 4, and forms a part of the inner peripheral portion 5a of the backup ring 5.

[0029] The outer peripheral portion 5c is the outer surface on the outer peripheral side of the ring-shaped backup ring 5 (on the cylinder chamber 2a side of the cylinder member 20), and is arranged in a state of being in contact with the inner wall of the cylinder chamber 2a. The gap-forming end face 5d is a portion on the outer peripheral side of the low-pressure chamber side end of the backup ring 5, and is formed to have a reduced diameter extending 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 face 5d constitutes a part of the outer peripheral portion 5c.

[0030] The high-pressure chamber side end face portion 5e is the high-pressure chamber side end face of the backup ring 5, and is arranged in contact with a portion on the outer peripheral side of the low-pressure chamber side end face portion 6b of the packing ring 6. The high-pressure chamber side end face portion 5e of the backup ring 5 and the high-pressure chamber side end face portion 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) in order to prevent the packing ring 6 from being deflected or tilted, and are arranged in a straight line in a longitudinal sectional view.

[0031] <Packing Ring> The packing ring 6 is a substantially cylindrical member interposed between the bottom ring 4 and the backup ring 5 and the spacer ring 8 in the annular gap C1. The packing ring 6 includes a low-pressure chamber side end face portion 6b that abuts against the high-pressure chamber side end face 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 face portion 6b and abuts against the cylinder member 20, a small-diameter outer peripheral portion 6f that is reduced in diameter compared to the large-diameter outer peripheral portion 6e and is connected to the high-pressure chamber side end face portion 6c, and a central outer peripheral portion 6g formed such 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 polyethylene, for example. The tip portion 6A of the packing ring 6 is a reduced-diameter protrusion.

[0032] The inner peripheral portion 6a is the sealing portion formed on the most axially centered side of the packing ring 6 and arranged in contact with the outer peripheral surface 3a of the plunger member 30. The low-pressure chamber side end face portion 6b is a portion arranged in contact with the high-pressure chamber side end face portion 5e of the backup ring 5 and the high-pressure chamber side end face portion 4c of the bottom ring 4. By being formed perpendicular to the axial direction (the sliding direction of the plunger member 30), this low-pressure chamber side end face portion 6b serves to maintain the shape of the vertical surface of the packing ring 6 and the function of keeping the concentric position of the packing ring 6.

[0033] The high-pressure chamber side end face portion 6c is an end face that is vertical in a longitudinal cross-sectional view formed on the high-pressure chamber RH side of the packing ring 6 and is formed in an annular shape in a side view. The high-pressure chamber side end face portion 6c is arranged in a state where the low-pressure chamber side end face portion 8c of the spacer ring 8 is separated when no load a in the low-pressure chamber RL direction is applied to the spacer ring 8. When a load a in the low-pressure chamber RL direction is applied to the spacer ring 8, the high-pressure chamber side end face portion 6c is pressed against the low-pressure chamber side end face portion 8c of the spacer ring 8, and the packing ring 6 is compressed.

[0034] The outer peripheral portion 6d is a cylindrical outer peripheral surface of the packing ring 6 and is formed in a stepped shape by a large-diameter outer peripheral portion 6e, a small-diameter outer peripheral portion 6f, and a central outer peripheral portion 6g.

[0035] The large-diameter outer peripheral portion 6e is the outer peripheral surface with the largest outer diameter in the outer peripheral portion 6d and is formed in a cylindrical shape parallel to the outer peripheral surface of the plunger member 30 at a portion closer to the low-pressure chamber RL. The inner wall of the cylinder chamber 2a of the cylinder member 20 is arranged in contact with this large-diameter outer peripheral portion 6e. The large-diameter outer peripheral portion 6e is interposed between the backup ring 5 and the elastic ring 7 and is arranged so that the backup ring 5 and the elastic ring 7 are separated from each other and do not contact each other.

[0036] The small-diameter outer peripheral portion 6f is a circumferential surface with a smaller diameter than the large-diameter outer peripheral portion 6e in the outer peripheral portion 6d and is formed in a cylindrical shape at a portion closer to the high-pressure chamber RH. The inner wall of the inner peripheral portion 7a of the annular elastic ring 7 is arranged in contact with this small-diameter outer peripheral portion 6f and is arranged in a non-contact state with the cylinder member 20.

[0037] The central outer peripheral portion 6g is a side surface portion having a tapered shape that connects from the large-diameter outer peripheral portion 6e to the small-diameter outer peripheral portion 6f of the packing ring 6. In the central outer peripheral portion 6g, the locking portion 7b of the packing ring 6 is arranged in contact with the portion on the shaft center side, and an annular gap (annular space) C3 is formed in the portion near the outer periphery.

[0038] The annular gap (annular space) C3 is a sealed space in the shape of a right triangle in a longitudinal sectional view formed between the central outer peripheral portion 6g of the packing ring 6, the gap-forming end surface 7d of the elastic ring 7, and the inner wall of the cylinder chamber 2a. The annular gap (annular space) C3 is formed in the portion near the outer periphery of the central outer peripheral portion 6g formed in an inclined shape in a longitudinal sectional view, thereby enhancing the wedge effect of the elastic ring 7 and playing a role.

[0039] As shown in FIGS. 1 and 2, the conduction groove 6i is a groove formed at the tip portion 6A of the packing ring 6. When the inner member 3 moves to the high-pressure side, the conduction groove 6i does not communicate with the annular gap (annular space) C3 formed by the outer member 2, the packing ring 6, and the elastic ring 7. When the inner member 3 moves to the low-pressure side, the conduction groove 6i communicates with the annular gap (annular space) C3.

[0040] Even when the inner member 3 repeats reciprocating movement, the fluid that enters the annular gap (annular space) C3 is discharged from the conduction groove 6i that functions as a relief flow path to the outside of the annular gap (annular space) C3, so that the inside of the annular gap (annular space) is not pressurized (the adverse effect due to back pressure is reduced), and damage to the outer member 2, the packing ring 6, and the elastic ring 7 that constitute the annular gap (annular space) C3 can be prevented.

[0041] As shown in FIG. 2(a), the conduction groove 6i can be formed singly or in plural. By arranging a plurality of them evenly in the circumferential direction of the tip portion 6A of the packing ring 6, the back pressure (trapped in the annular gap (annular space) C3) inside the cylinder can be evenly dispersed.

[0042] Since the conduction groove 6i is a location through which fluid passes, a protection part 6ib for the conduction groove can be arranged for the purpose of further taking measures against damage and the like. The protection part 6ib for the conduction groove may be anything that can be connected to the conduction groove 6i. Instead of the protection part 6ib for the conduction groove, it is also conceivable to perform a coating process on the surface of the tip 6A of the packing ring 6, etc.

[0043] The conduction groove 6i only needs to be able to function to conduct electricity as the inner member 3 moves. As shown in FIGS. 2(b) and 2(c), it goes without saying that the number of conduction grooves 6i can be appropriately changed, and the same applies to the height, width, depth, shape, etc.

[0044] Also, the width L2 of the conduction groove 6i can be made longer than the width L1 of the tip 6A of the packing ring 6. Although the elastic ring 7 repeats contraction and expansion due to the energy generated as the inner member 7 moves, since the error is extremely small, if the width of the conduction groove 6i is too short, the discharge of the fluid in the annular gap (annular space) C3, which is the purpose of forming the conduction groove 6i, will not function (as a relief circuit). Therefore, by forming the width L2 of the conduction groove 6i longer than the width L1 of the tip 6A of the packing ring 6, water conductivity can be surely obtained.

[0045] As shown in FIG. 3, in the case of the ultra-high pressure sealing device in a state where the ultra-high pressure is applied without forming the conduction groove 6i, forces in the directions of arrow c and arrow d are applied to the elastic ring 7, and it comes into a state of being in close contact with the outer member 2 and the packing ring 6. At this time, the area in the annular gap (annular space) C3 becomes smaller than before the ultra-high pressure is applied, and the pressure is in a state of being trapped.

[0046] Also, as shown in FIG. 4, in the case of the ultra-high pressure sealing device in the state when the application of the ultra-high pressure is released, forces in the directions of arrow ca and arrow da are applied to the elastic ring 7, and it comes into a state of being in close contact with the outer member 2 and the tip 6a of the packing ring 6. At this time, the area in the annular gap (annular space) C3 is also affected by the reaction in the state where the ultra-high pressure is applied, and becomes larger than before the ultra-high pressure is applied, and the back pressure is in a state of being relaxed.

[0047] And since the reciprocating pump generates high-pressure fluid by reciprocating the internal member 3, it will again be in the state when the ultra-high pressure of FIG. 3 is applied. Even if each element is sealed, it is difficult to completely prevent the intrusion of fluid, and fluid remains in the annular gap (annular space) C3. Further, after the intrusion, the area in the annular gap (annular space) C3 becomes smaller again. Therefore, the back pressure in the annular gap (annular space) C3 induces damage to the outer member 2, packing ring 6, and elastic ring 7 that constitute the annular gap (annular space) C3.

[0048] Therefore, in the ultra-high pressure sealing device of the present invention, by forming the conduction groove 6i, the back pressure in the annular gap (annular space) C3 can be prevented from being excessively trapped. The state when the ultra-high pressure shown in FIG. 5 is applied is basically the same as the energy and fluid movement acting in FIGS. 3 and 4. The difference lies in the mechanism when the ultra-high pressure load is removed, as shown in FIG. 6.

[0049] Forces in the directions of arrow ca and arrow da are applied to the elastic ring 7, and it is in a state of being in close contact with the outer member 2 and the tip 6a of the packing ring 6. However, due to the formation of the water conduction groove 6i, the fluid that has entered the annular gap (annular space) C3 is discharged in the direction of S1. Even if the ultra-high pressure is applied again, the back pressure does not accumulate inside the annular gap (annular space) C3, so damage to the outer member 2, packing ring 6, and elastic ring 7 that constitute the annular gap (annular space) C3 can be suppressed.

[0050] <Elastic ring> The elastic ring 7 is an annular member having a pentagonal shape (a polygon having five sides) in a longitudinal sectional view. The elastic ring 7 includes an inner peripheral portion 7a that is externally fitted to the small-diameter outer peripheral portion 6f of the packing ring 6 and abuts against this 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 that axial movement is restricted, 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.

[0051] Since the elastic ring 7 is externally fitted to the small-diameter outer peripheral portion 6f and the central outer peripheral portion 6g of the packing ring 6 and is disposed in a state of being pressed by the spacer ring 8, it is disposed so as to be compressed and adhered between the cylinder member 20 and the tapered central outer peripheral portion 6g. For this reason, the elastic ring 7 presses the packing ring 6 in the direction of the plunger member 30 (arrow b direction). As a result, the inner peripheral portion 7a and the locking portion 7b of the elastic ring 7 are in close contact with the small-diameter outer peripheral portion 6f and the central outer peripheral portion 6g of the packing ring 6, the outer peripheral portion 7c is in close contact with the inner wall surface of the cylinder chamber 2a, and the inner peripheral portion 6a of the packing ring 6 is in close contact with the outer peripheral surface of the plunger member 30, so that an initial pressure between the members can be obtained. The elastic ring 7 is, for example, a synthetic rubber having elasticity such as urethane rubber.

[0052] The inner peripheral portion 7a is the inner surface on the axial center side of the ring-shaped elastic ring 7 and is externally fitted to the small-diameter outer peripheral portion 6f of the packing ring 6. The locking portion 7b has a tapered shape conforming to the tapered shape of the packing ring 6 and is formed to have an increased diameter from the low-pressure chamber side end of the inner peripheral portion 7a in the direction of the outer peripheral portion. The locking portion 7b is externally fitted to a portion near the axial center of the central outer peripheral portion 6g of the packing ring 6 and forms a part of the inner peripheral portion 7a of the elastic ring 7.

[0053] The outer peripheral portion 7c is the outer surface on the outer peripheral side of the ring-shaped elastic ring 7 and is disposed in a state of being in contact with the inner wall of the cylinder chamber 2a. The gap-forming end surface 7d is a portion on the outer peripheral portion side of the low-pressure chamber side end of the elastic ring 7 and is formed perpendicularly from the low-pressure chamber side end of the outer peripheral portion 7c to the outer peripheral side end of the locking portion 7b.

[0054] The high-pressure chamber side end face portion 7e is the end face on the high-pressure chamber RH side of the elastic ring 7, and is arranged in a state where the outer peripheral end of the low-pressure chamber side end face portion 8c of the spacer ring 8 is in contact when no load a in the low-pressure chamber RL direction is applied to the spacer ring 8. That is, the high-pressure chamber side end face portion 7 of the elastic ring 7 is formed in a tapered shape so as to have a reduced diameter from the end on the outer peripheral portion 7c side to the end on the inner peripheral portion 7a side in the axial direction from the high-pressure chamber RH side to the low-pressure chamber RL side. When a load a in the low-pressure chamber RL direction is applied to the spacer ring 8, the entire end face of the low-pressure chamber side end face portion 8c of the spacer ring 8 is pressed, and the elastic ring 7 is compressed.

[0055] <Spacer ring> The spacer ring 8 is a metal cylindrical member fitted into the inner wall of the cylinder chamber 2a in a state of being in contact with the outer peripheral end of the high-pressure chamber side end face portion 7e of the elastic ring 7 in the high-pressure chamber RH. As shown in FIG. 1, the spacer ring 8 includes an outer peripheral portion 8a into which the plunger member 30 is inserted so as to be able to advance and retreat, an inner peripheral portion 8b fitted into the inner wall surface of the cylinder chamber 2a, and a low-pressure chamber side end face portion 8c disposed opposite to 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.

[0056] Furthermore, the spacer ring 8 can also have a water guiding groove 8d on the end face on the low-pressure side. By forming the water guiding groove 8d, the number of water guiding locations increases, and the fluid in the annular space C is prevented from accumulating, thereby reducing damage to the packing ring 6 and the elastic ring 7. As shown in FIG. 6, the fluid can be discharged in the direction of S2.

[0057] Furthermore, the spacer ring 8 can also have a central water guiding groove (hole) 8e in the central portion. By forming the central water guiding groove 8e, the fluid in the annular gap C is prevented from accumulating, thereby reducing damage to the packing ring 6 and the elastic ring 7. As shown in FIG. 6, the fluid can be discharged in the direction of S3.

[0058] Although the water conductivity by the central water conduit (hole) 8e is sufficient, the water conduit 8d is more likely to achieve a higher effect (reducing damage) because it is located on the low-pressure side of the spacer ring 8 and has more opportunities to contact the packing ring 6 and the elastic ring 7 at such locations. Note that the height, width, depth, shape, number, etc. of the water conduit 8d and the central water conduit (hole) 8e can be appropriately changed.

[0059] ≪Function≫ The operation of the ultra-high pressure sealing device 1 and the reciprocating drive pump 10 according to the embodiment of the present invention will be described.

[0060] The reciprocating drive pump 10 is arranged such that the elastic ring 7 in contact with the spacer ring 8 is compressed on the high-pressure chamber RH side of the packing ring 6. As a result, the pressure in the high-pressure chamber RH direction is transmitted to the backup ring 5 and the bottom ring 4 via the packing ring 6, and these members are in close contact without gaps, so an appropriate initial pressure can be obtained between each seal member.

[0061] Further, when a load in the direction from the high-pressure chamber RH side to the low-pressure chamber RL (arrow a direction) is applied to the spacer ring 8, the reciprocating drive pump 10 pushes and compresses the elastic ring 7 and the packing ring 6 in the low-pressure chamber RL direction. The elastic ring 7 is compressed and moved as a whole in the low-pressure chamber RL direction. The locking portion 7b moves along the tapered surface of the central outer peripheral portion 6g, and the outer peripheral portion 7c is pressed against and adhered to the inner wall surface of the cylinder chamber 2a to seal. Also, the locking portion 7b pushes the central outer peripheral portion 6g of the packing ring 6 in the axial direction (arrow b direction) and adheres the inner peripheral portion 6a to the plunger member 30 to seal. The packing ring 6 presses the high-pressure chamber side end faces 5e and 4c of the backup ring 5 and the bottom ring 4.

[0062] The low-pressure chamber side end face portion 6b of the packing ring 6 abuts against the high-pressure chamber side end face portion 5e of the backup ring 5 and the high-pressure chamber side end face portion 4c of the bottom ring 4, so that the ultra-high pressure axial direction (arrow e direction) pressing force transmitted from the packing ring 6 can be transmitted to both the backup ring 5 and the bottom ring 4 simultaneously. For this reason, the sealing property of the backup ring 5 against the inner wall surface of the cylinder chamber 2a and the sealing property of the bottom ring 4 against the plunger member 30 can be generated early to improve the sealing property.

[0063] The backup ring 5 is externally fitted to the small-diameter outer peripheral portion 4f of the bottom ring 4, so that the ultra-high pressure axial direction (arrow e direction) pressing force transmitted from the packing ring 6 can be shared by both the backup ring 5 and the bottom ring 4 respectively. Further, the small-diameter outer peripheral portion 4f of the bottom ring 4 can ensure the coaxiality of the bottom ring 4 and the backup ring 5 due to the external fitting of the backup ring 5, so that the outer peripheral portion 6d of the packing ring 6 can be properly brought into close contact with the inner wall surface of the cylinder chamber 2a.

[0064] Since the outer peripheral portion 5c of the backup ring 5 whose diameter is expanded in the outer peripheral direction (arrow g direction) is pressed against and brought into close contact with the inner wall surface of the cylinder chamber 2a, the sealing property with the inner wall surface of the cylinder chamber 2a can be improved. Further, the locking portion 5b of the wedge-shaped backup ring 5 presses the inner peripheral portion 4a of the bottom ring 4 on the axial center side in the axial center direction (arrow f direction) and brings it into close contact with the outer peripheral surface of the plunger member 30 to seal.

[0065] For this reason, the inner peripheral portion 4a of the bottom ring 4 can greatly improve the sliding characteristics, sealing performance, durability, and sealing life while ensuring the sealing property against the plunger member 30 in the ultra-high pressure state, so that it can be sealed even with an ultra-high pressure fluid of 500 MPa or more.

[0066] In the above embodiment, the ultra-high pressure sealing device 1 used at ultra-high pressure has been described, but it is not limited thereto, and it can be similarly applied to various high-pressure parts with a pressure lower than ultra-high pressure (500 MPa or more).

Description of Symbols

[0067] 1 Ultra-high pressure sealing device 2 Outer member 3 Inner member 4 Bottom ring 4a, 5a, 6a, 7a Inner peripheral part 4b, 6b Low-pressure chamber side end face part 4c, 5e, 6c High-pressure chamber side end face part 4d, 5c, 6d, 7c Outer peripheral part 4e, 6e Large-diameter outer peripheral part 4f, 6f Small-diameter outer peripheral part 4g, 6g Central outer peripheral part 6i Conductive groove 5 Backup ring 5b, 7b Locking part 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

1. An ultra-high pressure sealing device disposed in an annular gap formed between an outer member and an inner member, sealing the annular gap to partition a high-pressure chamber and a low-pressure chamber, comprising: a bottom ring that contacts and seals with the outer member on the low-pressure side; a backup ring that contacts and seals with the tip of the bottom ring on the high-pressure side; a packing ring that contacts and seals with the high-pressure side end faces of the bottom ring and the backup ring; an elastic ring that contacts and seals with the tip of the packing ring; the tip of the packing ring has a single or a plurality of conduction grooves; when the inner member moves to the high-pressure side, it is a part of the annular gap, and the annular space formed by the outer member, the packing ring, and the elastic ring does not communicate with the conduction grooves; when the inner member moves to the low-pressure side, the conduction grooves communicate with the annular space to discharge the fluid that has entered the annular space to the high-pressure side outside the annular space. An ultra-high pressure sealing device.

2. The ultra-high pressure sealing device according to claim 1, wherein a plurality of the conduction grooves are evenly arranged in the circumferential direction of the tip of the packing ring.

3. The ultra-high pressure sealing device according to claim 1 or claim 2, wherein the conduction grooves have a width longer than the width of the conduction grooves in the axial direction of the tip of the packing ring.

4. The ultra-high pressure sealing device according to any one of claims 1 to 3, further comprising a protection part for the conduction grooves to protect the conduction grooves.

5. Comprising a spacer ring that seals on the high-pressure side of the elastic ring, The ultra-high pressure sealing device according to any one of claims 1 to 4, wherein the spacer ring has a water conduction groove on the end face on the low-pressure side.

6. Comprising a spacer ring that seals on the high-pressure side of the elastic ring, The ultra-high pressure sealing device according to any one of claims 1 to 5, wherein the spacer ring has a central water conduction groove in the central part in the axial direction thereof.

7. A reciprocating drive pump having an ultra-high pressure sealing device according to any one of claims 1 to 6, and having a pressure of 500 MPa or more, wherein the outer member is a cylinder member, and the inner member is a plunger member. A reciprocating drive pump characterized by this.

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