Ultra-high pressure seals and reciprocating pumps

Abstract

To provide an ultrahigh pressure sealing device and a reciprocating pump that can enhance a water conducting property of fluid so that the effect of back pressure caused by reciprocation of a plunger is reduced, and can improve durability.SOLUTION: An ultrahigh pressure sealing device 1 comprises a bottom ring 4 for performing sealing by being in contact with an outside member 2 on a low-pressure side, a backup ring 5 for performing sealing by being in contact with a tip part of the bottom ring, a packing ring 6 for performing sealing by being in contact with high pressure side end surface parts 4c and 5e of the bottom ring and the backup ring, and an elastic ring 7 for performing sealing by being in contact with a tip part of the packing ring. The elastic ring comprises a U-shaped part. When an inside member 3 moves to a high-pressure side, communication with an annular space C3 formed by the outside member 2, the packing ring, and the elastic ring is not established. When the inside member moves to the low-pressure side, communication with the annular space is established.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ultra-high pressure sealing device and a reciprocating pump, and more particularly to an ultra-high pressure sealing device and a reciprocating pump that include an elastic ring having a U-shaped portion. [Background technology]

[0002] Conventionally, in a high-pressure pump having a pressure of 400 MPa, a sealing device is known which is configured by arranging a bottom ring, a backup ring, a packing ring, and an elastic ring in axial order from the low-pressure section to the high-pressure section.

[0003] For example, the seal device used in the high-pressure pump described in Patent Document 1 uses a high-strength stainless steel 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).

[0004] 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. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4123547 [Patent Document 2] Patent No. 6397377 Summary of the Invention [Problem to be solved by the invention]

[0006] By improving the sealing performance so that it can withstand ultra-high pressures (500 MPa or more), there is an increased chance that pressure will build up in the gaps between the packing ring and elastic ring when pressurizing the inside of the cylinder (moving the plunger member to the high-pressure side), and when depressurizing the inside of the cylinder (moving the plunger member to the low-pressure side), back pressure will remain in the gaps between the packing ring and elastic ring. However, if the back pressure remains and the inside of the cylinder is repeatedly pressurized and depressurized (the plunger member moves), there is a problem that the packing ring and elastic ring are subjected to more pressure than necessary, causing deformation and damage.

[0007] The present invention has been made in view of the above background, and aims to provide an ultra-high pressure sealing device and a reciprocating drive pump that can improve sealing performance at ultra-high pressures, increase fluid conductivity so that the U-shaped portion of the elastic ring formed between the outer peripheral protrusion and the inner peripheral protrusion reduces the effect of back pressure inside the cylinder caused by the reciprocating movement of the plunger, and improve durability. [Means for solving the problem]

[0008] 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 the tip of the bottom ring to seal, a packing ring that contacts the high pressure side end faces of the bottom ring and the backup ring to seal, and an elastic ring that contacts the tip of the packing ring to seal, and the elastic ring has a U-shaped portion, and when the inner member moves to the high pressure side, it is part of the annular gap and is in contact with the annular space formed by the outer member, the packing ring, and the elastic ring. The hyperbaric chamber When the inner member moves to the low pressure side without conducting, the annular space and The hyperbaric chamber Conduction. [Effects of the Invention]

[0009] The ultra-high pressure sealing device of the present invention has a U-shaped portion of the elastic ring formed between the outer peripheral protrusion and the inner peripheral protrusion, which acts in the opening direction of the U-shaped portion (the outer peripheral protrusion and the inner peripheral protrusion), thereby improving sealing performance at ultra-high pressures, and also acts in the closing direction of the U-shaped portion (the outer peripheral protrusion and the inner peripheral protrusion), thereby eliminating sealing, thereby increasing fluid conductivity and improving durability by reducing the effect of back pressure inside the cylinder due to the reciprocating movement of the plunger.As a result, this ultra-high pressure sealing device is particularly suitable for use in reciprocating drive pumps used in the high-pressure range (500 to 700 MPa). [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a main portion of an ultra-high pressure sealing device and a reciprocating pump according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of FIG. 1. [Figure 3] 1 is a cross-sectional view showing an elastic ring according to an embodiment of the present invention. [Figure 4] 1 is an enlarged view of a main part of an ultra-high pressure sealing device and a reciprocating pump according to an embodiment of the present invention, showing a state when ultra-high pressure is applied. FIG. [Figure 5] 1 is an enlarged view of the essential parts of the ultra-high pressure sealing device and the reciprocating pump according to an embodiment of the present invention, showing a state when the load of ultra-high pressure is released. FIG. [Figure 6] FIG. 1 is an enlarged view of a main part of a conventional ultra-high pressure sealing device and a reciprocating pump, showing the state when ultra-high pressure is applied. [Figure 7] FIG. 10 is an enlarged view of the essential parts of a conventional ultra-high pressure sealing device and a reciprocating pump, showing the state when the load of ultra-high pressure is released. DETAILED DESCRIPTION OF THE INVENTION

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

[0012] <Ultra-high pressure sealing device> As shown in Figure 1, the ultra-high-pressure sealing device 1 is suitable 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 that pressurize fluids. It is capable of sealing fluids with pressures of 500 MPa or more. The ultra-high-pressure sealing device 1 is disposed 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 separate a high-pressure chamber RH from a low-pressure chamber RL. Hereinafter, an example of the ultra-high-pressure sealing device 1 will be described, taking as an example a case where it is used in a reciprocating pump 10 (plunger pump) in which the outer member 2 is a cylinder member 20 that constitutes a pressure vessel and the inner member 3 is a plunger member 30 that moves back and forth within the cylinder member 20.

[0013] 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 within 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 surface 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.

[0014] <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 able to move back and forth, and is disposed within a housing (not shown).

[0015] <Inner member> The inner member 3 is a plunger member 30 (piston) that reciprocates using hydraulic pressure, etc. The inner member 3 is moved backward by, for example, 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 toward the high-pressure chamber RH, thereby fulfilling the function of a pump that pressurizes and discharges the high-pressure fluid in the high-pressure chamber RH.

[0016] <Annular gap> The annular gap C1 is a space that is cylindrical in vertical cross section and is formed between the plunger member 30 and the cylinder member 20, and is an installation space in which packing members (sealing members) such as the packing ring 6 and the 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, forming a seal that separates the high-pressure chamber RH side from the low-pressure chamber RL side, and preventing high-pressure fluid from leaking to the outside.

[0017] <Bottom ring> The bottom ring 4 is a substantially cylindrical member that is more rigid 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 abuts against the plunger member 30 (inner member 3), a large-diameter outer peripheral portion 4e that connects 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 smaller in diameter than the large-diameter outer peripheral portion 4e and connects to the high-pressure chamber side end face 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.

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

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

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

[0021] 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 disposed in contact with a portion of the low-pressure chamber side end surface 6b of the packing ring 6 near the axis.

[0022] The outer peripheral portion 4d is a 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 largest outer diameter portion of the outer peripheral surface of the outer peripheral portion 4d, and is formed cylindrically in a portion closer to the low-pressure chamber RL. The large-diameter outer peripheral portion 4e is disposed in contact with the inner wall of the cylinder chamber 2a of the cylinder member 20. The outer diameters of the large-diameter outer peripheral portion 4e of the bottom ring 4, the outer diameter of the outer peripheral portion 5c of the backup ring 5, the outer diameter of the large-diameter outer peripheral portion 6e of the packing ring 6, the outer diameter of the outer peripheral portion 7c of the elastic ring 7, and the outer diameter of the outer peripheral portion 8b of the spacer ring 8 are all substantially the same.

[0023] The small-diameter outer peripheral portion 4f is the smallest diameter peripheral surface of the outer peripheral portion 4d and is formed cylindrically at a 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 abutting small-diameter outer peripheral portion 4f and the inner peripheral portion 5a are disposed 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 are fitted together at non-tapered small-diameter outer peripheral portion 4f and inner peripheral portion 5a, ensuring coaxiality. The non-tapered, vertical high-pressure chamber side end face portion 4c and high-pressure chamber side end face portion 5e of the bottom ring 4 and backup ring 5 abut against the low-pressure chamber side end face portion 6b of the packing ring 6, thereby ensuring squareness and coaxiality, supporting the plunger member 30 so that it does not wobble, and improving the prevention of fluid leakage and the life of the packing.

[0025] The central outer peripheral portion 4g is a side portion (outer peripheral portion) having a tapered shape that connects the large diameter outer peripheral portion 4e to the small diameter outer peripheral portion 4f of the bottom ring 4. The central outer peripheral portion 4g is disposed in a state in which the locking portion 5b of the backup ring 5 abuts against the central portion 4g at a portion on the axial center side, and an annular gap C2 is formed in a portion near the outer periphery.

[0026] The annular gap C2 is a sealed annular space having a triangular shape in vertical cross section, which is 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 in a portion near the outer periphery of the central outer peripheral portion 4g, which is formed in an inclined shape in vertical cross section, and thereby serves to enhance the wedge effect of the backup ring 5.

[0027] <Backup ring> The backup ring 5 is a wedge-shaped ring-shaped member that is pentagonal (a polygon with five sides) in vertical cross section and is fitted onto the small-diameter outer peripheral portion 4f and 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 state where it is divided into two parts in vertical cross section: 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 is composed of an inner peripheral portion 5a that is fitted onto the small-diameter outer peripheral portion 4f of the bottom ring 4 and abuts against this small-diameter outer peripheral portion 4f, a locking portion 5b that is locked onto the central outer peripheral portion 4g of the bottom ring 4 so that axial movement is restricted, an outer peripheral portion 5c that abuts against the cylinder member 20, a gap-forming end face 5d formed in 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 inside surface on the axial 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 increases from the end of the inner peripheral portion 5a on the low-pressure chamber side toward the outer peripheral portion. The locking portion 5b is fitted onto the central outer peripheral portion 4g of the bottom ring 4 in a position close to the axial center, and forms 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 (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 a portion on the outer peripheral side 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.

[0030] The high-pressure chamber side end face 5e is the high-pressure chamber side end face of the backup ring 5, and is arranged to abut against an outer peripheral portion of the low-pressure chamber side end face 6b of the packing ring 6. The high-pressure chamber side end face 5e of the backup ring 5 and the high-pressure chamber side end face 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 on a straight line when viewed in vertical cross section, in order to prevent the packing ring 6 from being misaligned or tilted.

[0031] <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 face 6b that abuts against the high-pressure chamber-side end face 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 connects to the low-pressure chamber-side end face 6b and abuts against the cylinder member 20, a small-diameter outer peripheral portion 6f that is smaller in diameter than the large-diameter outer peripheral portion 6e and connects to the high-pressure chamber-side end face 6c, and a central outer peripheral portion 6g whose outer peripheral portion 6d is formed so as to connect 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 protrusion with a reduced diameter.

[0032] The inner peripheral portion 6a is formed closest to the axial center line of the packing ring 6, and is a sealing portion where the outer peripheral surface 3a of the plunger member 30 is disposed in contact therewith. The low-pressure chamber side end surface 6b is a portion that is disposed so as to abut 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. This low-pressure chamber side end surface 6b is formed perpendicular to the axial direction (the sliding direction of the plunger member 30), thereby fulfilling the function of maintaining the shape of the vertical surface of the packing ring 6 and the concentric position of the packing ring 6.

[0033] The high-pressure-chamber-side end surface 6c is a vertical end surface formed on the high-pressure chamber RH side of the packing ring 6 in a longitudinal cross section, and is formed into 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 6c is positioned in a state where it is spaced apart from the low-pressure-chamber-side end surface 8c of the spacer ring 8. When 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 6c is pressed by the low-pressure-chamber-side end surface 8c of the spacer ring 8, compressing the packing ring 6.

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

[0035] The large diameter outer peripheral portion 6e is the outer peripheral surface formed with the largest outer diameter on 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 location closer to the low pressure chamber RL. The large diameter outer peripheral portion 6e is arranged in contact with 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 come into contact with each other.

[0036] The small-diameter outer peripheral portion 6f is a peripheral surface of the outer peripheral portion 6d that is smaller in diameter than the large-diameter outer peripheral portion 6e, and is formed in a cylindrical shape at a portion closer to the high-pressure chamber RH. The small-diameter outer peripheral portion 6f is disposed in contact with the inner wall of the inner peripheral portion 7a of the annular elastic ring 7, but is not disposed in contact with the cylinder member 20.

[0037] The central outer peripheral portion 6g is a side portion having a tapered shape that connects the large-diameter outer peripheral portion 6e to the small-diameter outer peripheral portion 6f of the packing ring 6. The central outer peripheral portion 6g is disposed in a state in which the locking portion 7b of the packing ring 6 abuts on the central portion 6g at a portion on the axial center side, and an annular gap (annular space) C3 is formed at a portion near the outer periphery.

[0038] The annular gap (annular space) C3 is a sealed space with a right-angled triangle shape in vertical cross section, which is formed between the central outer peripheral portion 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 peripheral portion 6g, which is formed in an inclined shape in vertical cross section, and thereby enhances the wedge effect of the elastic ring 7 and fulfills its function.

[0039] As shown in Figure 6, when an ultra-high pressure sealing device is loaded with ultra-high pressure, forces are applied to the elastic ring 7' in the directions of arrows c and d, causing the outer member 2' and the packing ring 6' to come into close contact with each other. At this time, the area inside the annular gap (annular space) C3' becomes smaller than before the ultra-high pressure was applied, and pressure is trapped inside.

[0040] 7, in the case of the ultra-high pressure sealing device in the state where the ultra-high pressure load 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 end 6a' of the packing ring 6' are in close contact. At this time, the area inside the annular gap (annular space) C3' is affected by the reaction to the ultra-high pressure load, and becomes larger than before the ultra-high pressure load was applied, and the back pressure is relaxed.

[0041] Since the reciprocating drive pump generates high-pressure fluid by moving the inner member 3' back and forth, it will again be in the state shown in Figure 6 when ultra-high pressure is applied. However, even if each element is sealed, it is difficult to prevent fluid from entering 100%, and fluid will remain in the annular gap (annular space) C3', or if more fluid enters, 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'.

[0042] Therefore, in the ultra-high pressure sealing device of the present invention, by forming a U-shaped portion 7g of the elastic ring 7 between the outer peripheral protrusion 7e and the inner peripheral protrusion 7f, it is possible to prevent excessive back pressure from building up in the annular gap (annular space) C3. The state when ultra-high pressure is applied shown in Figure 4 is based on the same basic principles as the energy and fluid movement that acts in Figures 6 and 7. In other words, when the inner member 3 moves to the high-pressure side, the annular gap C1 is not connected to the annular space C3 formed by the outer member 2, the packing ring 6, and the elastic ring 7. However, it is difficult to completely prevent fluid infiltration. The difference is the mechanism that occurs when the ultra-high pressure load is released, as shown in Figure 5.

[0043] Forces are applied to the elastic ring 7 in the directions of 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 a U-shaped portion 7g between the outer peripheral protrusion 7e and the inner peripheral protrusion 7f, the energy of the fluid penetrating into the annular gap (annular space) C3 moving in the direction S3 causes the outer peripheral protrusion 7e of the elastic ring 7 to temporarily or intermittently deform into a shape that moves inward, and the fluid flows into the annular gap C1, thereby preventing back pressure from building up in the annular gap (annular space) C3. In other words, when the inner member 3 moves to the low-pressure side, the outer peripheral protrusion 7e temporarily or intermittently deforms into a shape that moves inward, and becomes connected to the outer peripheral protrusion annular space C3, allowing fluid to flow into the annular gap C1 and preventing back pressure from building up. By discharging the fluid that has entered the annular gap (annular space) C3 in the direction of S1, even if ultra-high pressure is applied again, back pressure does not build up inside the annular gap (annular space) C3, thereby suppressing damage to the outer member 2, packing ring 6, and elastic ring 7 that make up the annular gap (annular space) C3.

[0044] <Elastic ring> The elastic ring 7 is an annular member. The elastic ring 7 is composed of an inner peripheral portion 7a that fits over 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 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, an outer peripheral protrusion 7e formed on the outer peripheral portion on the spacer ring 8 side, an inner peripheral protrusion 7f formed on the inner peripheral portion on the spacer ring 8 side, and a U-shaped portion 7g that is recessed in a U-shape between the outer peripheral protrusion 7e and the inner peripheral protrusion 7f. The elastic ring 7 can be made of a synthetic rubber having elasticity, such as urethane rubber or nitrile rubber.

[0045] The elastic ring 7 is fitted onto the small-diameter outer peripheral portion 6f and the central outer peripheral portion 6g of the packing ring 6 and is arranged in a state where it is pressed against the spacer ring 8, so that it is compressed and tightly fitted between the cylinder member 20 and the tapered central outer peripheral portion 6g. Therefore, the elastic ring 7 presses the packing ring 6 toward the plunger member 30 (in the direction of arrow b). As a result, the inner peripheral portion 7a and the locking portion 7b of the elastic ring 7 are tightly fitted to 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 tightly fitted to the inner wall surface of the cylinder chamber 2a, and the inner peripheral portion 6a of the packing ring 6 is tightly fitted to the outer peripheral surface of the plunger member 30, thereby generating initial pressure between the respective members.

[0046] 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 increases 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 a portion of 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.

[0047] The outer peripheral portion 7c is the outer surface on the outer periphery side of the ring-shaped elastic ring 7, and is disposed in contact with the inner wall of the cylinder chamber 2a. The outer peripheral portion 7c is composed of a first outer peripheral portion 7ca formed at the tip of the outer peripheral protrusion 7e, and a second outer peripheral portion 7cb connected to the first outer peripheral portion 7ca and having a contact surface with a different inclination angle from the first outer peripheral portion 7ca. By forming the shape so that only the first outer peripheral portion 7ca is in close contact with the cylinder member 20 under normal circumstances, the outer peripheral protrusion portion 7e can be easily deformed when the fluid in the annular gap (annular space) C3 is pushed outward as the plunger member 30 moves.

[0048] The gap forming end surface 7d is a portion of the low pressure chamber side end of the elastic ring 7 on the outer periphery side, and is formed perpendicularly from the low pressure chamber side end of the outer periphery portion 7c to the outer periphery side end of the locking portion 7b.

[0049] The outer peripheral protrusion 7e is a portion corresponding to the outer peripheral portion formed on the spacer ring 8 side of the elastic ring 7. Normally (when the plunger member 30 is not moving), the first outer peripheral portion 7ca at the tip is in close contact with the cylinder member 20. As the plunger member 30 moves, the outer peripheral protrusion 7e adjusts between contact and non-contact with the cylinder member 20 in accordance with the rise or fall of the pressure in the annular space C, thereby maintaining a state in which the fluid in the annular space (annular space) C3 is less likely to become trapped.

[0050] The inner peripheral protrusion 7f is a portion that corresponds to the inner peripheral portion formed on the spacer ring 8 side of the elastic ring 7. Normally (when the plunger member 30 is not moving), the inner peripheral protrusion 7f is in close contact with the packing ring 6.

[0051] The U-shaped portion 7g is a recessed portion formed between the outer peripheral protrusion 7e and the inner peripheral protrusion 7f. By forming the U-shaped portion 7g, the movement of the outer peripheral protrusion 7e can be flexibly adjusted even if there is a pressure fluctuation due to the movement of the fluid.

[0052] Furthermore, the inclination angles of the outer peripheral protrusions 7e and the inner peripheral protrusions 7f are important for ensuring flexible movement of the outer peripheral protrusions 7e. By keeping the inclination angle α1 of the outer peripheral protrusions 7e, the inclination angle α2 of the inner peripheral protrusions 7f, and the inclination angle α3 of the outer periphery within appropriate ranges, it is possible to maintain sealing performance and improve back pressure prevention performance.

[0053] The inclination angle α1 of the outer peripheral protrusion 7e is preferably 15 to 25°, particularly 18°, relative to the first reference plane F1 parallel to the axis of the elastic ring 7 when the elastic ring 7 is viewed in cross section. By setting the inclination angle α1, the outer peripheral protrusion 7e comes into contact with the outer member 3, and the gripping force for sealing can be improved. The larger the inclination angles α1 and α2 are, the larger the size of the interior of the U-shaped portion 7g becomes, and when the inner member 3 moves to the high-pressure side, fluid enters the interior, increasing the contact pressure of the outer peripheral protrusion 7e on the outer member 3 and the contact pressure of the inner peripheral protrusion 7f on the inner member 2. However, if the inclination angles α1 and α2 are too large, variations in the load on the contact surfaces will occur, so setting them to appropriate angles will be more effective.

[0054] The inclination angle α2 of the inner peripheral protrusion 7f is preferably 5 to 15°, particularly 10°, relative to the second reference plane F2 parallel to the axis of the elastic ring 7 when the elastic ring 7 is viewed in cross section. Setting the inclination angle α2 makes it possible to improve the gripping force required for sealing when the inner peripheral protrusion 7f comes into contact with the inner member 2. If the angle is too large, the load applied to the contact surface will vary, so setting an appropriate angle is more effective.

[0055] When the elastic ring is viewed in cross section, the inclination angle α3 of the outer periphery is preferably 10 to 20°, particularly 15°, relative to a third reference plane F3 parallel to the axis of the elastic ring . By setting the inclination angle α3, the outer peripheral protrusion 7e can come into contact with the outer member 3, improving the gripping force for sealing. If the angle is too large, the load on the contact surface will be uneven, so setting it to a moderate angle will be more effective. The first reference plane F1, the second reference plane F2, and the third reference plane F3 are all in a parallel relationship.

[0056] Furthermore, by making the width W1 of the outer peripheral protrusion 7e and the width W2 of the inner peripheral protrusion 7f the same and making one longer or shorter, it is possible to ensure a sufficient gripping force with the outer member 3 and the inner member 2.

[0057] <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 peripheral end of the elastic ring 7 within the high-pressure chamber RH. As shown in Fig. 1, the spacer ring 8 is composed of an inner peripheral portion 8a into which the plunger member 30 is inserted and arranged so as to be able to move back and forth, an outer peripheral portion 8b fitted into the inner wall surface of the cylinder chamber 2a, and a high-pressure chamber side end face 6c of the packing ring 6 and a low-pressure chamber side end face 8c arranged opposite the elastic ring 7.

[0058] Furthermore, the spacer ring 8 can have a water guide groove 8d on its end surface on the low-pressure side. By forming the water guide groove 8d, the number of water guide points increases, preventing fluid from becoming trapped in the annular space C and reducing damage to the packing ring 6 and the elastic ring 7. As shown in Figure 5, the fluid can escape in the direction of S2.

[0059] Furthermore, the spacer ring 8 can have a central water guide groove (hole) 8e in the center. Forming the central water guide groove 8e prevents fluid from being trapped in the annular gap C, thereby reducing damage to the packing ring 6 and the elastic ring 7. As shown in Figure 5, the fluid can escape in the direction of S3.

[0060] Although the water conduction provided by the central water guide groove (hole) 8e is sufficient, the water guide groove 8d is located on the low-pressure side of the spacer ring 8 and is more likely to come into contact with the packing ring 6 and elastic ring 7, so it is more likely to have a greater effect (reduce damage). The height, width, depth, shape, number, etc. of the water guide groove 8d and the central water guide groove (hole) 8e can be changed as appropriate.

[0061] ≪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.

[0062] In the reciprocating pump 10, the elastic ring 7 is arranged on the high-pressure chamber RH side of the packing ring 6 in contact with the spacer ring 8 so that it is compressed. This allows pressure in the direction of the high-pressure chamber RH to be transmitted to the backup ring 5 and the bottom ring 4 via the packing ring 6, resulting in tight contact between these components with no gaps, and therefore an appropriate initial pressure can be obtained between each sealing component.

[0063] In addition, when a load is applied to the spacer ring 8 from the high-pressure chamber RH toward the low-pressure chamber RL (in the direction of arrow a), the reciprocating pump 10 pushes the elastic ring 7 and the packing ring 6 toward the low-pressure chamber RL, compressing them. The elastic ring 7 is compressed overall toward the low-pressure chamber RL, and the locking portion 7b moves along the tapered surface of the central outer periphery 6g, pressing the outer periphery 7c against the inner wall surface of the cylinder chamber 2a, providing a tight seal. The locking portion 7b also pushes the central outer periphery 6g of the packing ring 6 axially (in the direction of arrow b), causing the inner periphery 6a to tightly contact the plunger member 30 and provide a seal. The packing ring 6 presses against the high-pressure-chamber-side end faces 5e and 4c of the backup ring 5 and bottom ring 4.

[0064] 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 pressing force in the axial direction (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 establish a seal with the inner wall surface of the cylinder chamber 2a and the bottom ring 4 to quickly establish a seal with the plunger member 30, improving the sealing performance.

[0065] The backup ring 5 is fitted onto the small-diameter outer peripheral portion 4f of the bottom ring 4, so that the ultra-high pressure pressing force in the axial direction (in the direction of arrow e) transmitted from the packing ring 6 can be shared between the backup ring 5 and the bottom ring 4. Furthermore, the small-diameter outer peripheral portion 4f of the bottom ring 4, onto which the backup ring 5 is fitted, ensures concentricity between the bottom ring 4 and the backup ring 5, so that the outer peripheral portion 6d of the packing ring 6 can be tightly attached to the inner wall surface of the cylinder chamber 2a.

[0066] The backup ring 5 has an outer circumferential portion 5c, which is expanded in diameter in the outer circumferential direction (in the direction of arrow g), pressed against the inner wall surface of the cylinder chamber 2a and made intimate contact with the inner wall surface of the cylinder chamber 2a, thereby 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 circumferential portion 4a of the bottom ring 4, which is on the axial side, in the axial direction (in the direction of arrow f), making it in intimate contact with the outer circumferential surface of the plunger member 30 and making a seal.

[0067] As a result, the inner peripheral portion 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, and can therefore seal even ultra-high pressure fluids of 500 MPa or more.

[0068] In the above embodiment, an ultra-high pressure sealing device 1 for use at ultra-high pressures was described, but this is not limited to this and can be similarly applied to various high pressure areas at pressures lower than ultra-high pressures (500 MPa or more). [Explanation of symbols]

[0069] 1 Ultra-high pressure sealing device 2 Outer member 3 Inner member 4 Bottom ring 4a, 5a, 6a, 7a Inner circumference 4b, 6b Low pressure chamber side end surface 4c, 5e, 6c High pressure chamber side end surface 4d, 5c, 6d, 7c outer periphery 4e, 6e Large diameter outer periphery 4f, 6f small diameter outer periphery 4g, 6g central outer periphery 5 Backup ring 5b, 7b Locking part 6 packing rings 7 Elastic Rings 7ca First outer periphery 7cb Second outer periphery 7e Outer protrusion 7f Inner peripheral protrusion 7g U-shaped part 8 Spacer ring 8d Water channel 8e Central water channel 10 Reciprocating pump 20 Cylinder member 30 Plunger member C1, C2 Annular gap C3 Annular gap (annular space) F1, F2, F3 reference plane RH hyperbaric chamber RL Low Pressure Chamber α1 Inclination angle of peripheral protrusion α2 Inclination angle of inner peripheral protrusion α3 Inclination angle of outer surface

Claims

1. 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 the tip of the bottom ring; 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 elastic ring has a U-shaped portion, 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 high-pressure chamber, When the inner member moves to the low pressure side, the annular space and the high pressure chamber communicate with each other.

2. The elastic ring is an outer peripheral protrusion formed on the outer peripheral side and in contact with the outer member; 2. The ultra-high pressure sealing device according to claim 1, further comprising: an inner peripheral protrusion formed on an inner peripheral side of the packing ring and contacting the packing ring.

3. The outer peripheral protrusion is a first outer circumferential portion formed at a tip of the elastic ring; 3. The ultra-high pressure sealing device according to claim 2, further comprising: a second outer periphery that is connected to the first outer periphery on the low pressure chamber side and has a contact surface that has an inclination angle relative to a third reference plane F3 that is parallel to the axis of the elastic ring when the elastic ring is viewed in cross section, the inclination angle being different from that of the first outer periphery.

4. The ultra-high pressure sealing device according to claim 2 or 3, wherein the inclination angle of the inner peripheral surface of the outer peripheral protrusion is 15 to 25 degrees with respect to a first reference plane F1 parallel to the axis of the elastic ring when the elastic ring is viewed in cross section.

5. The ultra-high pressure sealing device of claim 2, wherein the inclination angle of the outer peripheral surface of the inner peripheral protrusion portion is 5 to 15 degrees with respect to a second reference plane F2 parallel to the axis of the elastic ring when the elastic ring is viewed in cross section.

6. An ultra-high pressure sealing device as described in claim 3, wherein when the elastic ring is viewed in cross section, the inclination angle of the first outer peripheral portion is 10 to 20 degrees relative to the third reference plane F3.

7. a spacer ring sealing the high-pressure side of the elastic ring; 3. 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.

8. a spacer ring sealing the high-pressure side of the elastic ring; 3. The ultra-high pressure sealing device according to claim 1, wherein the spacer ring has a central water guide groove in the center.

9. A reciprocating pump equipped with the ultra-high pressure sealing device according to claim 1 or 2, the outer member is a cylinder member; The reciprocating drive pump, wherein the inner member is a plunger member.

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