Sealing device for rods

Abstract

The present invention relates to a sealing device for sealing a rod (2) movable translationally and / or rotationally within a high pressure chamber (31) of a pressure-resistant housing (3) filled with a liquid medium between the high pressure chamber (31) and a low pressure region (8), the sealing device comprising a seal cylinder (4) held within the housing (3) and forming a first annular gap (9) between an outer jacket surface (42) of the seal cylinder (4) and an inner wall (32) of the housing (3) that defines the high pressure chamber (31), the inner diameter of the jacket inner surface (41) of the seal cylinder (4) being dimensioned such that the rod (2) is enveloped by the seal cylinder (4) while a second annular gap (10) is formed that forms a dynamic seal, the first annular gap (9) being defined by the seal cylinder (4) and the inner wall (32) of the housing (3) that defines the high pressure chamber (31). a pressure ring (5) for statically sealing the first annular gap (9) and for deforming a part of the jacket inner surface (41) of the seal cylinder (4) in the direction of the rod (2), the pressure ring is located on the jacket outer surface (42) of the seal cylinder (4) near the low-pressure side end face (44), a seal ring (7) for statically sealing the first annular gap (9) is arranged in contact with the outer surface (42) of the seal cylinder (4) near the high-pressure side end face (45), the seal cylinder (4) has at least one connecting channel (43) extending from the outer surface (42) to the inner surface (41), and the position of the connecting channel (43) is provided in accordance with the material of the seal cylinder (4) in order to prevent deformation of the seal cylinder (4) in an area away from the pressure ring (5).

Description

Technical Field

[0001] The present invention relates to a sealing device for a rod according to the first part of claim 1.

Background Art

[0002] A general sealing device is known, for example, from European Patent No. 1 353 096. In this publication, a sealing ring is used to seal a rod, and the rod moves in a transition region between a high-pressure region and a low-pressure region of a guide chamber of a housing that guides the rod. The sealing ring surrounds the rod and is partially deformed by the high pressure in the high-pressure region with the help of a pressing ring, so that the deformation of the sealing ring reduces the gap between the sealing ring and the rod to an extent that allows the rod to leak only a desired amount of fluid.

[0003] [[ID=十七]] Such a gap sealing device has been actually proven.

[0004] The problem is that especially at very high pressures in the high-pressure range up to 3000 bar (3059 kgf / cm 2 ) or 4000 bar (4079 kgf / cm 2 ), the operating pressure applied to the outer surface of the sealing cylinder becomes very large, so that depending on the elastic modulus of the material of the sealing cylinder, the sealing cylinder may sometimes be deformed too much even in front of the pressing ring.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a sealing device for high-pressure equipment that ensures durable operation regardless of the material of the sealing cylinder.

Means for Solving the Problems

[0006] This object is solved by a sealing device having the features of claim 1.

[0007] The sealing device of the present invention, which seals a rod that can move translationally and / or rotationally within a high-pressure chamber of a pressure-resistant housing filled with a liquid medium between a high-pressure chamber and a low-pressure region, has a sealing cylinder that can be housed within the housing, and a first annular gap is formed between the outer surface of the sealing cylinder and the inner wall of the housing that separates the high-pressure chamber.

[0008] The inner diameter of the circumferential inner surface of the seal cylinder is sized such that the rod can be surrounded by the cylinder, while forming a second annular gap that forms a dynamic seal.

[0009] The sealing device further includes a pressing ring that contacts the outer surface of the sealing cylinder jacket near the low-pressure end face, the pressing ring statically sealing the first annular gap and deforming a portion of the inner surface of the sealing cylinder jacket in the rod direction.

[0010] To form this deformation, a pressure ring that receives a portion of the rod in the low-pressure region is attached to the housing. The pressure ring maintains a state where the seal cylinder is pressed into the housing, and presses against the stepped projection of the pressure-resistant housing, thereby forming deformation on a portion of the inner surface of the seal cylinder's jacket.

[0011] To statically seal the first annular gap, a seal ring, to which fluid pressure is dynamically applied, is positioned in contact with the outer surface of the seal cylinder near the high-pressure side end face. Furthermore, the seal cylinder has at least one connecting channel extending from its outer surface to its inner surface.

[0012] The connection channel is positioned in an area away from the pressing ring and is adapted to the material of the seal cylinder to prevent deformation that would restrict the function of the seal cylinder.

[0013] A first annular gap adjacent to the high-pressure side end face of the seal cylinder is sealed, and a connecting channel provided in the seal cylinder, which fluidically connects the two annular gaps, allows the fluid pressure acting on the outer surface of the seal cylinder jacket to be adjusted to the fluid pressure of the second annular gap acting as a throttling gap, depending on the position of the connecting channel. As the distance from the high-pressure side end face of the seal cylinder increases, the overall pressure within the second annular gap decreases to the overall pressure in the region of the connecting channel within the second annular gap.

[0014] As a result, the pressure acting on the outer surface of the seal cylinder can be adapted to the respective material of the seal cylinder by positioning the connecting channel within the seal cylinder, so that the desired deformation and load of the seal cylinder can be adapted according to its elastic modulus and occur only in the region of the pressing ring.

[0015] Advantageous embodiments of the present invention are the subject matter of the dependent claims. According to one advantageous embodiment, the connecting channel is introduced into the area of ​​the jacket of the seal cylinder between the pressing ring and the seal ring, and the connecting channel is spaced at least 10% of the distance between the pressing ring and the seal ring from the pressing ring or the seal ring.

[0016] As a result, the pressure applied to the outer surface of the seal cylinder is reduced, making it possible to use a variety of materials in the seal cylinder. In a preferred embodiment, a ring sheet is formed on the outer surface of the seal cylinder near the high-pressure side end face of the seal cylinder to firmly hold the seal ring.

[0017] In a particularly preferred embodiment, the ring seat is configured as a step extending from the high-pressure side end face of the seal cylinder into the outer shell surface of the seal cylinder.

[0018] Thus, during assembly, the sealing ring can be slipped onto the sealing cylinder from the high-pressure side end face in a very simple manner. According to another preferred embodiment of the present invention, the high-pressure side end face of the sealing cylinder is covered with a ring cap.

[0019] The advantage of using such an annular cap is that it enables a free low-stress configuration of the housing with a radius independent of the support surface without a radius required for sealing to the high-pressure region.

[0020] According to a further preferred embodiment, the sealing cylinder has a collar near the low-pressure side end face, and the pressing ring is placed on the back of the collar facing away from the low-pressure side end face.

[0021] This enables accurate positioning of the pressing ring and the sealing cylinder itself, particularly the positioning of the longitudinal axis of the sealing cylinder.

[0022] After the sealing cylinder is inserted into the pressure-resistant housing, the pressing ring is compressed between the collar and the step of the pressure-resistant housing, causing the sealing cylinder to undergo a desired deformation in the direction of the second annular gap.

[0023] The sealing cylinder is preferably made of a ceramic material, hard metal, steel, particularly stainless steel, bronze or plastic.

[0024] The device of a rod movable in translation and / or rotation in the high-pressure chamber of a pressure-resistant housing filled with a liquid medium according to the present invention has a sealing cylinder for the purpose of separating the high-pressure chamber from the low-pressure region, and the sealing cylinder is housed in the housing and forms a first annular gap between the annular outer surface of the sealing cylinder and the inner surface of the housing partitioning the high-pressure chamber.

[0025] A part of the rod is housed within the seal cylinder to form a second annular gap that forms a dynamic seal, and the pressing ring statically seals the first annular gap and deflects a part of the inner surface of the jacket of the seal cylinder in the direction of the rod that abuts against the outer surface of the jacket of the seal cylinder near the low-pressure side end face.

[0026] To statically seal the first annular gap, a seal ring is disposed on the outer surface of the seal cylinder near the high-pressure side end face.

[0027] The seal cylinder has at least one connection channel extending from its outer surface to its inner surface, through which the first annular gap is fluidly connected to the second annular gap.

Brief Description of the Drawings

[0028] Preferred embodiments will be described in more detail below with reference to the accompanying drawings. [Figure 1] It is a cross-sectional view of a rod and a housing surrounding the rod, and includes a seal cylinder disposed within the housing. [Figure 2] It is a cross-sectional view of the device shown in FIG. 1, and schematically shows the general pressures on the outer surface of the jacket and the inner surface of the seal cylinder during the pressure stroke of the device. [Figure 3] It is a display corresponding to FIG. 2 during the suction stroke of the device.

Modes for Carrying Out the Invention

[0029] In the following description of the drawings, terms such as up, down, left, right, front, back, etc. refer only to the exemplary representations and positions of the seal device, housing, seal cylinder, rod, annular gap, connection channel, etc. selected in each figure. These terms should not be understood in a limiting sense, that is, different operating positions, or mirror-symmetric designs, etc. may change these criteria.

[0030] In the following, a static seal is understood to be a fluid seal between two bodies that do not move relative to each other. In the following, a dynamic seal is understood to be a fluid seal or reduction of flow between two bodies that move relative to each other to an acceptable level.

[0031] Figures 1 to 3 show sealing devices for a rod 2 extending between the high-pressure chamber 31 and the low-pressure region 8 of the housing 3, respectively. The rod 2 can be translated along its longitudinal axis L in the direction of translational movement T. The rod 2 can also be rotated. Rotational motion of the rod 2 about its longitudinal axis L is also possible. At least one portion of rod 2 is movably mounted inside housing 3.

[0032] For example, in the region of the pressing ring 11, a seal cylinder 4 is provided to separate the high-pressure chamber 31 from the low-pressure region 8. This seal cylinder 4 is housed within the housing 3, and a first annular gap 9 is formed between the circumferential outer surface 42 of the seal cylinder 4 and the inner wall 32 of the housing 3, which forms the boundary of the high-pressure chamber 31.

[0033] Furthermore, the thrust ring 11 shown in Figures 1 to 3 first supports the rod 2 and then presses the seal cylinder 4 into the housing 3, ensuring that the thrust ring 11 is securely screwed into the housing.

[0034] Rod 2 passes through a passage in the seal cylinder 4, which is bounded by the inner surface 41 of the seal cylinder 4's jacket. The diameter of the inner surface 41 of the seal cylinder 4 is slightly larger than the diameter of the outer surface 42 of the rod 2. As a result, the rod 2, together with the seal cylinder 4, forms a dynamic seal also known as a gap seal. Such a gap seal is characterized in that, at the high-pressure end of the gap seal, high pressure is also present in the annular gap 10, but gradually decreases towards the low-pressure end of the annular gap 10.

[0035] As mentioned at the beginning, and also referred to in European Patent No. 1 353 096, in order to maintain leakage as a result of using such a small throttle gap, a pressing ring 5 is provided near the low-pressure end face 44 on the outer surface 42 of the jacket of the seal cylinder 4, as shown in Figures 1 to 3. As soon as the thrust ring 11 is screwed into the housing 3, a portion of the inner surface 41 of the seal cylinder 4 is deformed in the direction of the rod 2, thereby pressing the thrust ring 5 against the stepped shoulder of the housing 3.

[0036] As a result of the force applied to the longitudinal axis L of the rod 2, the pressing ring 5 deforms, and at that time, the pressure-resistant housing 3 resists expansion by the seal cylinder 4 itself from two sides and from a third side extending perpendicular to the direction of the force F in the axial direction of the rod 2. A force is generated by the pressing ring 5, and this force is essentially directed radially toward the rod 2, causing the desired deformation on the inner surface 41 of the jacket of the seal cylinder 4 in the direction of the rod 2.

[0037] Furthermore, the pressing ring 5 statically seals the first annular gap 9 between the outer surface 42 of the jacket of the seal cylinder 4 and the inner wall 32 of the housing 3 that defines the boundary of the high-pressure chamber 31.

[0038] Furthermore, as shown in Figures 1 to 3, a seal ring 7 for statically sealing the first annular gap 9 is placed on the outer surface 42 of the jacket of the seal cylinder 4 near the high-pressure side end face 45. In this way, the seal ring 7 prevents the pressure inside the high-pressure chamber 31 from acting on the annular gap 9.

[0039] Furthermore, the seal cylinder 4 has at least one connecting channel 43 extending from the outer surface 42 to the inner surface 41, through which the first annular gap 9 is connected to the second annular gap 10, allowing fluid to flow back and forth. As a result, the first annular gap 9 can receive the pressure present at the level of the connecting channel 43 within the second annular gap 10, which is configured as a throttle gap.

[0040] As a result, a predetermined pressure continues to act on the outer surface 42 of the seal cylinder 4 to compensate for the pressure on the second annular gap 10, preventing or at least significantly reducing deformation that would limit the function of the seal cylinder 4 in the region of the annular gaps 9 and 10. The deformation that limits function refers specifically to the radial deformation of the seal cylinder 4 toward the outer surface of rod 2, which is understood to potentially cause blockage of rod 2.

[0041] The sealing of the first annular gap 9 on both sides, provided by the pressing ring 5, the sealing ring 7, and the connecting channel 43 within the sealing cylinder 4, creates an improved pressure balance on both sides of the cylinder shell surface of the sealing cylinder 4 compared to systems known from the prior art, thereby enabling a variety of materials for the sealing cylinder 4.

[0042] The connecting channel 43 is preferably introduced into the jacket region of the seal cylinder 4 between the pressing ring 5 and the seal ring 7, and the connecting channel 43 is at a distance of at least 10%, preferably at least 25%, of the distance between the pressing ring 5 and the seal ring 7 from the pressing ring 5 or the seal ring 7. The positioning of the connecting channel depends in particular on the material selected for the seal cylinder 4.

[0043] In the embodiments shown in Figures 1 to 3, the connecting channel 43 is inserted approximately in the center between the low-pressure end face 44 and the high-pressure end face 45. Alternatively, multiple connecting channels 43 extending within the same radial plane of the seal cylinder 4 are also conceivable.

[0044] The seal cylinder 4 is preferably made of a ceramic material, a hard metal, steel, especially stainless steel, bronze, or a plastic made from one or more of the above materials, or a mixture thereof. Depending on the choice of material or material mixture from which the seal cylinder is made, or the E-coefficient of the material, the connecting channel is positioned so as to prevent deformation of the seal cylinder 4 in areas away from the pressing ring 5.

[0045] Figure 2 shows an example of the pressure applied to the side surface of the seal cylinder 4 during the pressing stroke of the rod 2. As already explained above, the pressure pi acting on the inner surface 41 of the seal cylinder 4 decreases from the high-pressure side to the low-pressure side within the second annular gap 10.

[0046] Furthermore, the pressure pa applied to the outer surface 42 of the jacket is constant due to the sealing of the first annular gap 9 provided by the pressing ring 5 and the sealing ring 7, and corresponds to the pressure on the inner surface 41 of the jacket of the seal cylinder 4 at the level of the connecting channel 43.

[0047] As a result, particularly near the low-pressure end of the first annular gap 9, the pressure difference is significantly reduced compared to systems known from the prior art, and sufficient high-pressure pressure exists even in the region of the low-pressure end of the first annular gap 9. Furthermore, the reduced pressure pa applied to the outer surface 42 of the shell leads to a lower load on the pressing ring 5.

[0048] Figure 3 shows the configuration corresponding to Figure 2 during the suction stroke of rod 2, where the pressure on the high-pressure side is significantly low, and therefore the pressure pi on the inner surface 41 of the jacket of seal cylinder 4 in the second annular gap 10 is generally constant, and therefore the pressure pa applied to the outer surface 42 of the jacket of seal cylinder 4 is also low accordingly.

[0049] In the embodiments shown in Figures 1 to 3, the rod 2 is configured as a plunger for a high-pressure system, and a valve seat 12, preferably an intake valve and a pressure valve, is located at the high-pressure end of the rod 2. Preferably, a sleeve 13 is provided to guide the rod 2 beyond the seal cylinder 4 to the high-pressure side, and the sleeve 13 further reduces the high-pressure chamber 31 filled with the liquid medium. To receive the seal ring 7, an annular receiving portion 47 is formed on the outer surface 42 of the jacket of the seal cylinder 4 near the high-pressure side end face 45 of the seal cylinder 4, as shown in Figures 1 to 3.

[0050] In this case, the ring seat 47 is preferably designed as a step extending from the high-pressure side end face 45 of the seal cylinder 4 to the outer shell surface 42 of the seal cylinder 4. Furthermore, it is preferable that the high-pressure side end face 45 of the seal cylinder 4 is covered by the ring cap 6. [Explanation of symbols]

[0051] List of reference symbols 2 rods 21 Sheath 22 Guide Chamber 23 High-voltage range 3 Housing 31 High-pressure chamber 32 Inner wall 33 stages 34 stages 35 Low pressure surface 4 Seal Cylinder 41 Inside of the jacket 42 Jacket exterior 43 connection channels 44 Front 45 Front 46 colors 47 Ring receiving section 5. First pressing ring 6 Ring caps 7. Second pressure ring 8 Low-voltage range 9. First annular gap 10. Second annular gap 11. Compression ring 12 High-pressure nozzle 13 sleeves 14 Leak Channels T translational direction X direction Y direction Z direction pi Pressure within the second annular gap Pa pressure within the first annular gap

Claims

1. A sealing device for sealing a rod (2) that is translationally and / or rotationally movable within the high-pressure chamber (31) of a pressure-resistant housing (3) filled with a liquid medium, between a high-pressure chamber (31) and a low-pressure region (8), The seal cylinder (4) is housed within the housing (3) and forms a first annular gap (9) between the outer jacket surface (42) of the seal cylinder (4) and the inner wall (32) of the housing (3) that separates the high-pressure chamber (31). The inner diameter of the inner surface (41) of the seal cylinder (4) is sized such that the rod (2) is enclosed by the seal cylinder (4) while forming a second annular gap (10) that forms a dynamic seal. A pressing ring (5) is located near the low-pressure end face (44) and contacts the outer surface (42) of the jacket of the seal cylinder (4) to statically seal the first annular gap (9), and also deforms a portion of the inner surface (41) of the jacket of the seal cylinder (4) toward the rod (2). In a sealing device comprising a pressing ring (11) fixed to the housing (3) in a low-pressure region (8) and receiving a portion of the rod (2), thereby pressing the pressing ring (5) against the stepped projection of the pressure-resistant housing (3), maintaining the pressure of the seal cylinder (4) against the housing (3) and forming deformation of a portion of the inner surface (41) of the jacket of the seal cylinder (4), A seal ring (7) for statically sealing the first annular gap portion (9) is positioned in contact with the outer surface (42) of the seal cylinder (4) near the high-pressure side end face (45). The seal cylinder (4) has at least one connecting channel (43) extending from the outer surface (42) to the inner surface (41), The sealing device is characterized in that the position of the connection channel (43) is provided in a region away from the pressing ring (5) in order to prevent deformation of the seal cylinder (4), and is adapted to the material of the seal cylinder (4).

2. The connecting channel (43) is introduced into the area of ​​the jacket of the seal cylinder (4) between the pressing ring (5) and the seal ring (7), The sealing device according to claim 1, wherein the connecting channel (43) is spaced at least 10% of the distance between the pressing ring (5) and the sealing ring (7) from the pressing ring (5) or the sealing ring (7).

3. The sealing device according to claim 2, wherein the connecting channel (43) is spaced at least 25% of the distance between the pressing ring (5) and the sealing ring (7) from the pressing ring (5) or the sealing ring (7).

4. A sealing device according to any one of claims 1 to 3, wherein an annular receiving portion (47) is integrally formed on the outer surface (42) of the jacket of the seal cylinder (4) near the high-pressure side end face (45) of the seal cylinder (4), and the seal ring (7) is received in the receiving portion (47).

5. The sealing device according to claim 4, wherein the receiving portion (47) of the ring is configured as a stepped portion extending from the high-pressure side end face (45) of the seal cylinder (4) into the outer surface (42) of the jacket of the seal cylinder (4).

6. The sealing device according to any one of claims 1 to 3, wherein the high-pressure side end face (45) of the seal cylinder (4) is covered by a ring cap (6).

7. The sealing device according to any one of claims 1 to 3, wherein the sealing cylinder (4) has a collar (46) near the low-pressure side end face (44), and a pressing ring (5) is supported on the back side of the collar (46) which faces away from the low-pressure side end face (44).

8. The sealing device according to any one of claims 1 to 3, wherein the seal cylinder (4) is made of ceramic material.

9. A device comprising a rod (2) that is translationally and / or rotationally movable within a high-pressure chamber (31) of a pressure-resistant housing (3) filled with a liquid medium, A seal cylinder (4) is provided to separate the high-pressure chamber (31) from the low-pressure region (8), and the seal cylinder (4) is received inside the housing (3), forming a first annular gap (9) between the annular outer surface (42) of the seal cylinder (4) and the inner wall (32) of the housing (3) that separates the high-pressure chamber (31). A portion of the rod (2) is received within the seal cylinder (4) to form a second annular gap (10) that forms a dynamic seal. A pressing ring (5) is positioned against the outer surface (42) of the seal cylinder (4) near the low-pressure end face (44) to statically seal the first annular gap (9) and to deform a portion of the inner surface (41) of the seal cylinder (4) toward the rod (2). In the low-pressure region (8), the pressing ring (11) that receives a portion of the rod (2) is fixed to the housing (3) and maintains a state in which the seal cylinder (4) is pressed into the housing (3), while the pressing ring (5) is pressed against the stepped projection of the pressure-resistant housing (3). In a device in which a portion of the inner surface (41) of the jacket of the seal cylinder (4) deforms toward the rod (2) by pressing the pressing ring (11) against the low-pressure end face of the housing (3) and the seal cylinder (4), A seal ring (7) for statically sealing the first annular gap portion (9) is placed on the outer surface (42) of the seal cylinder (4) near the high-pressure side end face (45). The seal cylinder (4) has at least one connecting channel (43) extending from the outer surface (42) to the inner surface (41), and the first annular gap portion (9) is connected to the second annular gap portion (10) via the connecting channel (43) so that fluid can pass through it. The device is characterized in that the position of the connection channel (43) is provided in a region away from the pressing ring (5) in order to prevent deformation of the seal cylinder (4) and is suited to the material of the seal cylinder (4).

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