Sealing device

Abstract

A sealing device (1) is a sealing device for achieving sealing of an annular gap. The sealing device (1) is provided with a sealing ring (2). One sealing ring (2) exhibits desired sealing performance with respect to fluids even in low-temperature environments.

Description

Technical Field

[0001] This invention relates to a sealing device, and more particularly to a sealing device suitable even for low-viscosity fluids. Background Technology

[0002] To seal the gap between a reciprocating component and the cylindrical hole into which the component is inserted, sealing devices with sealing rings have been used. For example, a sealing ring is mounted on the piston of a pump to prevent or suppress fluid leakage while causing the piston to pressurize the fluid (see, for example, Patent Document 1).

[0003] Existing technical documents Invention Patent Documents Invention Patent Document 1: Japanese Patent Application Publication No. 2016-014481 Summary of the Invention

[0004] The problem that the invention aims to solve For a long time, sealing devices have required a structure that can seal the fluid pumped by the pump without leakage, even in low-temperature environments. For example, a known sealing device arranges multiple sealing rings in series to form a sealing structure, and achieves fluid sealing in low-temperature environments by setting a multi-stage closure structure. On the other hand, such sealing devices require a simpler structure.

[0005] The present invention was made in view of the above-mentioned problems, and its object is to provide a sealing device that can achieve the desired sealing performance relative to the fluid with a simple construction even in low temperature environments.

[0006] Methods for solving problems To achieve the above objectives, the sealing device of the present invention is a sealing device for achieving a sealing of an annular gap, the sealing device having a sealing ring that exhibits the desired sealing performance to fluids even in low-temperature environments.

[0007] In a sealing device according to one aspect of the present invention, the fluid is a low-viscosity fluid.

[0008] In a sealing device according to one aspect of the present invention, the sealing ring is a sealing ring for achieving a seal of an annular gap, the sealing ring is arc-shaped about an axis and has a pair of ends in the circumferential direction, the pair of ends forming a closure, and the radial width of the pair of ends is smaller than the radial width of the central portion between the pair of ends.

[0009] In one aspect of the sealing device of the present invention, the sealing ring has an inner circumferential surface facing the inner circumferential side and an outer circumferential surface facing the outer circumferential side, the width being the width between the inner circumferential surface and the outer circumferential surface, the inner circumferential surface having no radial height difference, and the outer circumferential surface having no radial height difference.

[0010] In a sealing device according to one aspect of the invention, the ratio of the radial width of the pair of ends to the radial width of the central portion is a value between 0.2 and 0.6.

[0011] In a sealing device according to one aspect of the invention, the value of the radial width is continuous around the axis.

[0012] In a sealing device according to one aspect of the invention, the radial width increases from one of the pair of ends toward the central portion, and the radial width increases from the other of the pair of ends toward the central portion.

[0013] In a sealing device according to one aspect of the invention, the outer peripheral surface is along a cylindrical surface with the axis as its central axis, and the inner peripheral surface is along a cylindrical surface having a central axis that is radially offset from the axis.

[0014] One aspect of the present invention relates to a sealing device that uses a fluid with a viscosity lower than that of water as the object to be sealed.

[0015] One aspect of the present invention relates to a sealing device for sealing the gap between a reciprocating component and a cylindrical hole into which the component is inserted.

[0016] The effects of the invention The sealing device according to the present invention can achieve the desired sealing performance relative to the fluid with a simple construction, even in low-temperature environments. Attached Figure Description

[0017] Figure 1 This is a front view of the sealing device according to an embodiment of the present invention.

[0018] Figure 2 It is a three-dimensional diagram of the sealing device.

[0019] Figure 3 This is a cross-sectional view showing a sealing device installed between the piston and cylinder of a pump that pressurizes liquids, in its operational state.

[0020] Figure 4 This is a cross-sectional view showing a sealing device installed between the piston and cylinder of a pump that pressurizes liquids, in its operational state.

[0021] Figure 5 This is a diagram showing the general structure of a sealing performance testing device used to perform sealing performance tests on sealing devices.

[0022] Figure 6 This is a graph showing the results of the sealing performance test.

[0023] Symbol Explanation 1 Sealing device, 2 Sealing ring, 2a Joint, 3 Central part, 4 Inner circumferential surface, 5 Outer circumferential surface, 6, 7 Sides, 10, 20 Ends, 11, 21 Height difference, 30 Gap, 31 Central part, 100 Pump, 101 Piston, 102 Outer circumferential surface, 103 Groove, 103a Bottom surface, 103b, 103c Sides, 110 Cylinder, 111 Inner circumferential surface, 112 Hole, 200 Sealing performance test device, 201 Piston simulator, 202 Outer circumferential surface, 203 Groove, 210 Cylinder simulator, 211 Inner circumferential surface, 212 Hole, 213, 214 Cover, 215, 216 Pipe components, 220 Container, d Distance, R, R1, R2 Thickness ratio, r1, r2 Radius, t, t1, t2, t3; Width (radial width), x, x1, x2; Axis. Detailed Implementation

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] The sealing device 1 according to embodiments of the present invention is a sealing device for sealing an annular gap, used in pumps that pressurize liquids. Pumps using the sealing device 1 are, for example, pumps that pressurize cryogenic liquid fuels for general industrial applications. For example, the cryogenic liquid fuel could also be liquid hydrogen fuel. Specifically, the sealing device 1 is used to seal the annular gap between a piston, which is a reciprocating component, and a cylinder having a cylindrical orifice into which the piston can be inserted. It should be noted that the sealing device according to the present invention is not limited to pumps that pressurize liquids. The sealing device according to the present invention can be used in other pumps, other devices or mechanisms, structures, etc.

[0026] Figure 1 This is a front view of the sealing device 1 according to an embodiment of the present invention. Figure 2 This is a perspective view of the sealing device 1. The sealing device 1 includes a sealing ring 2. The sealing ring 2 exhibits the desired sealing performance to the fluid even at low temperatures. The structure of the sealing device 1 will be described in detail below.

[0027] The sealing ring 2 is arc-shaped around the axis x1 and has a pair of ends 10, 20 in the circumferential direction. The pair of ends 10, 20 form a mortise 2a. The radial widths t1, t2 of the sealing ring 2 at the pair of ends 10, 20 are smaller than the radial width t3 of the central portion (hereinafter also referred to as the "central portion") 3 between the pair of ends 10, 20. The structure of the sealing ring 2 will be described in detail below. It should be noted that in Figure 1 , Figure 2 The image shows the sealing ring 2 in a free state without any external force applied. Furthermore, radial direction refers to the direction orthogonal to the axis x1.

[0028] like Figure 1 , Figure 2 As shown, the sealing ring 2 is a generally arc-shaped member with an end, having a shape that accommodates an annular groove. The shape of the sealing ring 2, based on the cross-section of the plane containing the axis x1, is, for example, rectangular or generally rectangular. Figure 1 , Figure 2 As shown, in its free state, the sealing ring 2 is not annular, and a gap 30 extending in the circumferential direction is formed between end 10 and end 20. As described later, in its use state, the sealing ring 2 contacts the inner circumferential surface of the cylinder and elastically deforms, with ends 10 and 20 overlapping in the axial direction x1 to form a joint 2a.

[0029] The sealing ring 2 has an inner circumferential surface 4, which faces the inner circumferential side (radially inner side), and an outer circumferential surface 5, which faces the outer circumferential side (radially outer side). The inner circumferential surface 4 has no radial elevation difference and is a smooth surface, for example, a cylindrical surface extending along the axis x2. Similarly, the outer circumferential surface 5 has no radial elevation difference and is a smooth surface, for example, a cylindrical surface extending along the axis x1. Furthermore, the sealing ring 2 has side surfaces 6 and 7, which are arcuate surfaces extending in the x-direction. The side surfaces 6 and 7 are opposite to each other in the x-direction and extend between the inner circumferential surface 4 and the outer circumferential surface 5.

[0030] The radial width (width t) of the sealing ring 2 is continuous around the axis x1. It should be noted that the width t of the sealing ring 2 is the distance between the inner circumferential surface 4 and the outer circumferential surface 5 in the radial direction. The width t of the sealing ring 2 increases from the end 10 towards the central portion 3. It should be noted that the central portion 3 is the central part of the sealing ring 2 between the end 10 and the end 20, as described above; that is, the central part of the sealing ring 2 in the circumferential direction between the end 10 and the end 20. Furthermore, the width t of the sealing ring 2 increases from the end 20 towards the central portion 3. The width t of the sealing ring 2 between the end 10 and the central portion 3 increases, for example, in the same or approximately the same way as the width t of the sealing ring 2 between the end 20 and the central portion 3.

[0031] Specifically, the width t of the sealing ring 2 is, for example, as shown in the figure. Figure 1 As shown, it gradually increases from end 10 toward the central portion 3. Similarly, specifically, the width t of the sealing ring 2 is, for example, as shown... Figure 1 As shown, the width t of the sealing ring 2 between the end 10 and the central portion 3 gradually increases from the end 20 towards the central portion 3. Furthermore, the width t of the sealing ring 2 between the end 10 and the central portion 3 gradually increases in the same or approximately the same manner as the width t of the sealing ring 2 between the end 20 and the central portion 3. It should be noted that the width t of the sealing ring 2 may not necessarily increase gradually from the end 10 towards the central portion 3. For example, the width t of the sealing ring 2 may have a fixed range between the end 10 and the central portion 3. Similarly, the width t of the sealing ring 2 may not necessarily increase gradually from the end 20 towards the central portion 3. For example, the width t of the sealing ring 2 may have a fixed range between the end 20 and the central portion 3.

[0032] The outer circumferential surface 5 of the sealing ring 2 is, for example, a cylindrical surface or a substantially cylindrical surface with axis x1 as its central axis or approximately its central axis. The radius r1 of the outer circumferential surface 5 is, for example, larger than the radius of the inner circumferential surface of the cylinder of the pump described later. The inner circumferential surface 4 of the sealing ring 2 is, for example, a cylindrical surface or a substantially cylindrical surface with axis x2 as its central axis or approximately its central axis. The radius r2 of the inner circumferential surface 4 is larger than the radius of the bottom surface of the groove formed on the piston of the pump described later. The axis x2 is offset radially from the axis x1 toward the gap 30 side. Furthermore, the axis x2 is, for example, parallel or substantially parallel to the axis x1. Specifically, the axis x2 is, for example, as follows: Figure 1 As shown, the gap 30 is offset radially from axis x1 towards the center 31 by a specified distance (distance d). It should be noted that the center 31 of the gap 30 is as follows: Figure 1 As shown, the gap 30 is located at the middle position in the circumferential direction.

[0033] As described above, the widths t1 and t2 of the sealing ring 2 at each end 10 and 20 are smaller than the width t3 of the sealing ring 2 at the central portion 3. It should be noted that the width t1 of the sealing ring 2 at the end 10, specifically, is, for example, the width t at the end (end 4a) of the inner circumferential surface 4 (described later) (refer to...). Figure 1 , Figure 2 Similarly, the width t2 of the sealing ring 2 at end 20, specifically, for example, the width t at the end (end 4b) of the inner circumferential surface 4 described later (see reference). Figure 1 , Figure 2For example, the ratio of the width t1 of the end portion 10 to the width t3 of the central portion 3, i.e., the thickness ratio R1 (t1 / t3), is a value between 0.2 and 0.6. That is, the thickness ratio R1 (t1 / t3) is a value greater than 0.2 and less than 0.6. Similarly, for example, the ratio of the width t2 of the end portion 20 to the width t3 of the central portion 3, i.e., the thickness ratio R2 (t2 / t3), is a value between 0.2 and 0.6. That is, the thickness ratio R2 (t2 / t3) is a value greater than 0.2 and less than 0.6. Since the thickness ratio R1 (t1 / t3) and the thickness ratio R2 (t2 / t3) are the same or approximately the same value, the thickness ratio of both will be referred to as the thickness ratio R hereafter.

[0034] As described above, the width t of the sealing ring 2 increases from the ends 10, 20 toward the central portion 3, and the thickness of the sealing ring 2 in the circumferential direction is greater than that from the ends 10, 20 toward the central portion 3, and becomes 1 at the central portion 3.

[0035] The sealing ring 2, for example, forms a known special stepped cut shape for the joint 2a. Figure 1 As shown, height difference portions 11 and 21 with special stepped cut shapes are formed at the ends 10 and 20, respectively. Height difference portion 11 is formed on the outer periphery side of the inner circumferential surface 4, extending laterally in the circumferential direction relative to the inner circumferential surface 4 at end 4a of end 10. Similarly, height difference portion 12 is formed on the outer periphery side of the inner circumferential surface 4, extending laterally in the circumferential direction relative to the inner circumferential surface 4 at end 4b of end 20. Height difference portion 11 is provided on side 6, for example, to form a height difference on side 6, and height difference portion 21 is provided on side 7, for example, to form a height difference on side 7. In the use state of the sealing ring 2, the sealing ring 2 elastically deforms, and height difference portions 11 and 12 overlap in the axial x1 direction. In other words, height difference portions 11 and 12 overlap each other within a predetermined range throughout the circumferential direction, forming a joint 2a with a special stepped cut shape. It should be noted that the opening 2a formed on the sealing ring 2 in the use state is not limited to an opening with a special stepped cut shape, but can also be an opening with, for example, a stepped cut shape, a straight cut shape, or an oblique cut shape. That is, the shape used to form the opening 2a of the ends 10 and 20 is not limited to a special stepped cut shape, but can also have, for example, a stepped cut shape, a straight cut shape, or an oblique cut shape.

[0036] The sealing ring 2 is made of resin. The resin material forming the sealing ring 2 includes, for example, polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polyimide (PI), and polyamide-imide (PAI). It should be noted that the resin material of the sealing ring 2 may also contain, for example, fillers used to improve sliding properties and strength. As described above, the sealing ring 2 is used in a pump that pressurizes liquids. The pressurized liquid, which is the object of sealing, is, for example, a low-viscosity liquid. When the sealing device 1 is used in a low-temperature environment, a material with a small coefficient of linear expansion is preferred for the sealing ring 2. For example, the material of the sealing ring 2 has a coefficient of linear expansion of less than 15 × 10⁻⁶. -5 The material should be at a temperature of / ℃. Furthermore, when the sealing device 1 is used in a low-temperature environment, PEEK, with a low coefficient of linear expansion, is preferred as the resin material for the sealing ring 2. It should be noted that a low-temperature environment refers to, for example, an environment where the ambient temperature is lower than the atmospheric temperature. Specifically, a low-temperature environment refers to, for example, an environment with an ambient temperature of -253℃, or an environment with an ambient temperature lower than -253℃.

[0037] The function of the sealing device 1 having the above-described structure will be explained below. Figure 3 , Figure 4 This is a cross-sectional view of the sealing device 1 in use, installed between the piston 101 and cylinder 110 of the pump 100 for pressurizing liquid. Figure 3 A cross-section based on the plane containing the axis x of cylinder 110 is shown. Figure 4 A cross-section orthogonal to the x-axis is shown. It should be noted that in... Figure 4 In the diagram, sealing ring 2 is not shown in cross-section.

[0038] like Figure 3 , Figure 4 As shown, an annular groove 103 is formed on the outer peripheral surface 102 of the piston 101. In the groove 103, the inner peripheral surface 4 of the sealing ring 2 faces the bottom surface 103a of the groove 103, accommodating only one sealing ring 2. In the pump 100, the piston 101 with the sealing ring 2 installed in the groove 103 is inserted into the hole 112 of the cylinder 110. In the pump 100, the reciprocating motion of the piston 101 within the hole 112 of the cylinder 110 presses the liquid, and the liquid is pumped in the direction of arrow a.

[0039] As described above, the radius of the outer circumferential surface 5 of the sealing ring 2 is larger than the radius of the inner circumferential surface 111 of the hole 112 dividing the cylinder 110. Therefore, in the pump 100, the sealing ring 2 comes into contact with the inner circumferential surface 111 of the cylinder 110 and deforms elastically, flexing towards the inner circumferential side to form a joint 2a. That is, the outer circumferential surface 5 of the sealing ring 2 is pressed towards the inner circumferential side by the inner circumferential surface 111 of the cylinder 110, causing the sealing ring 2 to deform elastically. The height difference portion 11 of the end 10 and the height difference portion 12 of the end 20 of the sealing ring 2 overlap in the axial x1 direction within a specified range throughout the circumference, forming a joint 2a with a special stepped cut shape. As a result, the radius of the outer circumferential surface 5 of the sealing ring 2 becomes smaller, and the outer circumferential surface 5 of the sealing ring 2 and the inner circumferential surface 111 of the cylinder 110 face each other throughout the entire circumference around the axial x.

[0040] The width t of the sealing ring 2 decreases from the central portion 3 toward the ends 10 and 20, i.e., it becomes thinner. Therefore, when the sealing ring 2 is inserted into the hole 112 of the cylinder 110, the sealing ring 2 elastically deforms in a flexural manner on both sides toward the axis x, with the central portion 3 as the center. In the sealing ring 2, the portion with a smaller width t is more compressed by the inner circumferential surface 111 and elastically deforms in a more flexural manner. Since the ends 10 and 20 of the sealing ring 2 and their vicinity are even smaller, i.e. thinner, they are more likely to elastically deform in a more inward flexural manner, and are therefore more compressed by the inner circumferential surface 111 and elastically deform in a more flexural manner. In this way, the sealing ring 2 deforms when inserted into the hole 112 of the cylinder 110 and forms a closing opening 2a. Furthermore, the outer circumferential surface 5 and the inner circumferential surface 111 of the cylinder 110 face each other throughout the entire circumference of the axis x.

[0041] Within the pump 100, at and near the ends 10 and 20 of the sealing ring 2, in order for the outer peripheral surface 5 to contact the inner peripheral surface 111 of the cylinder 110, the ends 10 and 20 of the sealing ring 2 need to elastically deform in a manner that flexes inward along the inner peripheral surface 111 of the cylinder 110. In the sealing ring 2, the width t of the ends 10 and 20 and their vicinity becomes smaller towards the ends 10 and 20, making it easier for the ends 10 and 20 of the sealing ring 2 to deform along the inner peripheral surface 111 of the cylinder 110. Therefore, in the pump 100, even at and near the ends 10 and 20 of the sealing ring 2, where a gap is easily formed between the sealing ring 2 and the inner peripheral surface 111 of the cylinder 110, the deformation of the outer peripheral surface 5 of the sealing ring 2 along the inner peripheral surface 111 of the cylinder 110 can suppress the formation of a gap between the outer peripheral surface 5 and the inner peripheral surface 111 of the cylinder 110. Therefore, at and near the ends 10, 20 of the sealing ring 2, the radial gap between the outer peripheral surface 5 and the inner peripheral surface 111 of the cylinder 110 is small, and furthermore, the circumferential range of this gap is small. Thus, in the pump 100, the outer peripheral surface 5 of the sealing ring 2 contacts the inner peripheral surface 111 of the cylinder 110 approximately around the axis x, resulting in a small gap. Alternatively, at and near the ends 10, 20 of the sealing ring 2, the radial gap between the outer peripheral surface 5 and the inner peripheral surface 111 of the cylinder 110 is nonexistent, and in the pump 100, the outer peripheral surface 5 of the sealing ring 2 contacts the inner peripheral surface 111 of the cylinder 110 approximately around the axis x, resulting in no gap.

[0042] It should be noted that the offset (distance d) of the axis x2 of the inner circumferential surface 4 of the sealing ring 2 relative to the axis x1 of the outer circumferential surface 5 is set, for example, in a manner that causes the sealing ring 2 as described above to elastically deform along the inner circumferential surface 111 of the cylinder 110.

[0043] Thus, in the pump 100, the sealing ring 2 allows its outer peripheral surface 5 to contact the inner peripheral surface 111 of the cylinder 110 approximately around the entire circumference of the axis x. Furthermore, the radial gap between the outer peripheral surface 5 of the sealing ring 2 and the inner peripheral surface 111 of the cylinder 110 is small or nonexistent, and the circumferential range of this gap is also small. Therefore, even if the liquid pumped by the piston 101 in the cylinder 110 is a low-viscosity liquid, the sealing device 1, through a single sealing ring 2, suppresses leakage of the pumped liquid from the outer peripheral surface 5 of the sealing ring 2 and the inner peripheral surface 111 of the cylinder 110. Consequently, the sealing device 1 can improve the pumping efficiency of the pump 100 through a single sealing ring 2. Thus, the sealing device 1 does not require a multi-stage sealing structure by arranging multiple sealing rings in series as in the past; instead, with a simple structure of a single sealing ring 2, it can maintain sealing performance or prevent a decrease in sealing performance even if the pumped fluid is a low-viscosity liquid. Therefore, the sealing device 1 can exhibit the desired sealing performance relative to low-viscosity fluids using a single sealing ring 2. It should be noted that low viscosity refers to, for example, a viscosity lower than that of water.

[0044] Furthermore, since the sealing ring 2 is prone to elastic deformation in a manner that allows it to flex more from the central portion 3 toward the ends 10 and 20, even when the sealing ring 2 contracts in a low-temperature environment, the outer peripheral surface 5 of the sealing ring 2 can still contact the inner peripheral surface 111 of the cylinder 110 approximately around the entire circumference of the axis x. That is, although the sealing ring 2 contracts in a low-temperature environment in a manner that creates a gap between the outer peripheral surface 5 of the sealing ring 2 and the inner peripheral surface 111 of the cylinder 110, the outer peripheral surface 5 of the sealing ring 2 maintains contact with the inner peripheral surface 111 of the cylinder 110 approximately around the entire circumference of the axis x because the elastically deformed sealing ring 2 deforms toward its natural state along with this contraction.

[0045] To ensure that the outer circumferential surface 5 of the sealing ring 2 maintains approximately full circumference contact with the inner circumferential surface 111 of the cylinder 110 even when the sealing ring 2 contracts at low temperatures, the radius r1 of the outer circumferential surface 5 is adjusted. Specifically, to ensure that the outer circumferential surface 5 of the sealing ring 2 maintains approximately full circumferential contact with the inner circumferential surface 111 of the cylinder 110 even when the sealing ring 2 contracts at low temperatures and is in a state of elastic deformation, the radius r1 of the outer circumferential surface 5 is adjusted. The radius r1 of the outer circumferential surface 5 is adjusted, for example, to correspond to the radius of the inner circumferential surface 111 of the cylinder 110. In this case, even without thermal shrinkage, although the sealing ring 2 is elastically deformed by a strong constraint force from the cylinder 110, the ends 10, 20 of the sealing ring 2 and their vicinity are prone to deform along the inner circumferential surface 111 of the cylinder 110, thus suppressing the formation of a gap between the outer circumferential surface 5 and the inner circumferential surface 111 of the cylinder 110.

[0046] As described above, the sealing device 1 according to this embodiment, with a single sealing ring 2, can maintain sealing performance relative to the fluid or suppress the decrease in sealing performance even in low-temperature environments. Therefore, the sealing device 1 according to this embodiment can exhibit the desired sealing performance with a single sealing ring 2 even in low-temperature environments. This desired sealing performance is, for example, a sealing performance arbitrarily set by the user or others based on the applicable object and situation of the sealing device 1. Specifically, for example, the desired sealing performance is set by setting the leakage amount of the sealed object relative to a specified usage time under specified usage conditions such as specified temperature and ambient pressure.

[0047] Furthermore, since a material with a lower coefficient of linear expansion is more effective at suppressing shrinkage of the sealing ring 2 in low-temperature environments, using a material with a low coefficient of linear expansion is effective in maintaining sealing performance relative to the fluid or suppressing a decrease in sealing performance in low-temperature environments. Moreover, as described above, the sealing device 1 of this embodiment, with a single sealing ring 2, can maintain sealing performance relative to low-viscosity fluids or suppress a decrease in sealing performance. Therefore, the sealing device 1 of this embodiment can exhibit the desired sealing performance relative to low-viscosity fluids with a single sealing ring 2.

[0048] It should be noted that, under the condition of use, such as Figure 3 As shown, when the piston 101 moves in the direction of arrow a, the side 7 of the sealing ring 2 contacts the side 103b of the groove 103 of the piston 101, sealing the annular gap between the piston 101 and the inner circumferential surface 111 of the cylinder 110. Conversely, when the piston 101 moves in the direction of arrow b, the side 6 of the sealing ring 2 contacts the side 103c of the groove 103 of the piston 101, sealing the annular gap between the piston 101 and the inner circumferential surface 111 of the cylinder 110. Furthermore, in the operating state, the axis x of the cylinder 110 coincides with or is approximately coincident with the axis x1 of the outer circumferential surface 5 of the sealing ring 2.

[0049] Next, the sealing performance test, which evaluated the sealing performance of sealing device 1, will be explained. Figure 5 This is a diagram showing the general structure of the sealing performance testing apparatus 200 used to perform the sealing performance test on the sealing device 1. (See diagram for example.) Figure 5As shown, the sealing performance testing apparatus 200 has a piston simulator 201 and a cylinder simulator 210 that respectively mimic the piston 101 and cylinder 100 of the pump 100 described above. The piston simulator 201 has an outer peripheral surface 202 identical to the outer peripheral surface 102 of the piston 101, and a groove 203 identical to the groove 103 of the piston 101 is formed on the outer peripheral surface 202. Furthermore, the cylinder simulator 210 has an inner peripheral surface 211 identical to the inner peripheral surface 111 of the cylinder 110, and a hole 212 is formed therein. The piston simulator 201, which houses the sealing ring 2 of the sealing device 1 in the groove 203, is inserted into the hole 212 of the cylinder simulator 210, and the sealing ring 2 is in the same operating state as when installed on the pump 100. The cylinder simulator 210 is as follows... Figure 5 As shown, it is cylindrical and open at both ends, which are closed by covers 213 and 214. Furthermore, tubular members 215 and 216 are installed on covers 213 and 214, respectively, passing through covers 213 and 214 and communicating with holes 212. Additionally, the piston simulator 201 is supported stationary by covers 213 and 214.

[0050] In the sealing performance test, the sealing performance test device 200, such as... Figure 5 The sample is placed in container 220 containing coolant L and submerged within it. However, the tips of pipe members 215 and 216 protrude from the surface of coolant L. Coolant L is, for example, liquid nitrogen (LN2). In this state, with the sealing ring 2 within the sealing performance test apparatus 200 at a specified test temperature, test fluid pressurized to a specified test pressure P is introduced from pipe member 215 into orifice 212. This state is maintained, and the leakage amount of test fluid during a specified period is investigated. The leakage amount of test fluid is measured by recovering and quantifying the test fluid leaking from sealing ring 2 from pipe member 216. It should be noted that nitrogen is used in the test fluid. Furthermore, regarding the test conditions, the test temperature is set to approximately -190°C, and the test pressure P is set to 0.5 MPa to 8 MPa.

[0051] Furthermore, as sealing rings 2, sealing rings 2 with a thickness ratio R of 0.3 (Test Example 1) and sealing rings 2 with a thickness ratio R of 0.55 (Test Example 2) were prepared, and sealing performance tests were conducted on Test Examples 1 and 2. In addition, for a conventional sealing ring (Comparative Example 1) with a sealing ring width t that is uniformly uniform throughout the circumference, a sealing performance test was conducted using the sealing performance testing apparatus 200 described above. Figure 6 This is a graph showing the results of sealing performance tests for sealing ring 2 (Test Examples 1 and 2) and a conventional sealing ring (Comparative Example 1).

[0052] like Figure 6As shown, the leakage of Test Example 1 (thickness ratio P 0.3) was reduced by 95% compared to Comparative Example 1. Furthermore, the leakage of Test Example 2 (thickness ratio P 0.55) was reduced by 70% compared to Comparative Example 1. Thus, it is evident that the sealing ring 2 of the sealing device 1 can significantly improve the sealing performance for low-viscosity fluids compared to conventional sealing rings. Furthermore, it is foreseeable that the relationship between the thickness ratio R and the leakage rate will become... Figure 6 The relationship is shown by the dashed line.

[0053] As described above, the sealing device 1 according to an embodiment of the present invention, through a sealing ring 2, can maintain the sealing performance of the fluid even in low-temperature environments, or can suppress the decrease in the sealing performance of the fluid even in low-temperature environments. Thus, the sealing device 1 according to an embodiment of the present invention can achieve the desired sealing performance for the fluid with a simple construction, even in low-temperature environments. Furthermore, the sealing device 1 according to an embodiment of the present invention can maintain the sealing performance or suppress the decrease in sealing performance even if the object being sealed becomes a low-viscosity object, through a sealing ring 2. Thus, the sealing device 1 according to an embodiment of the present invention can achieve the desired sealing performance for low-viscosity fluids with a simple construction.

[0054] While the present invention has been described above through the embodiments, its technical scope is not limited to that described in the above embodiments. Those skilled in the art will readily recognize that various modifications or alterations can be made to the above embodiments. As is evident from the scope of the claims, such modifications or alterations can also be included within the technical scope of the present invention.

[0055] The embodiments described above are for the purpose of understanding the present invention and are not intended to limit or explain the present invention. Furthermore, the above embodiments do not limit the scope of application of the present invention; the present invention can encompass all objects that can be utilized therein. The structural elements, their configurations, materials, conditions, shapes, and dimensions, etc., provided in the above embodiments are not limited to the examples and can be appropriately modified. For example, the present invention includes differences arising in implementation due to manufacturing tolerances, etc. Furthermore, within the scope of technical non-contradiction, structural elements shown in different embodiments can be partially substituted or combined with each other. Moreover, the structures can be appropriately and selectively combined to achieve at least a portion of the aforementioned problems and effects.

[0056] For example, the cross-sectional shape of the sealing ring 2 is not limited to rectangular or approximately rectangular. For example, the inner circumferential surface 5 of the sealing ring 2 may also have a protrusion projecting inwards, and the cross-sectional shape of the sealing ring 2 may also be T-shaped. Furthermore, multiple sealing rings 2 may be used in an arrangement. For example, multiple grooves 103 may be formed at intervals along the x-axis on the piston 101, and sealing rings 2 may be installed in each of these grooves 103. Moreover, the sealing ring 2 is not limited to pumps subjected to static pressure as described above, but may also be used in pumps subjected to dynamic pressure. For example, the sealing ring 2 can be used to achieve a seal between a shaft rotating around an axis and a through-hole through which the shaft passes, and may also be disposed between relatively rotating outer and inner components.

Claims

1. A sealing device for achieving a seal in an annular gap. The sealing device includes a sealing ring. The sealing ring exhibits the desired sealing performance to fluids even in low-temperature environments.

2. The sealing device according to claim 1, wherein, The fluid is a low-viscosity fluid.

3. The sealing device according to claim 1 or 2, wherein, The sealing ring is used to achieve a seal in the annular gap. The sealing ring is arc-shaped around the axis and has a pair of ends in the circumferential direction. The pair of ends form a closure. The radial width at the pair of ends is smaller than the radial width of the central portion between the pair of ends.

4. The sealing device according to claim 3, wherein, The sealing ring has an inner circumferential surface facing the inner circumferential side and an outer circumferential surface facing the outer circumferential side. The width is the width between the inner circumferential surface and the outer circumferential surface. The inner circumferential surface does not have a radial height difference. The outer peripheral surface does not have a radial height difference.

5. The sealing device according to claim 4, wherein, The ratio of the radial width at the pair of ends to the radial width at the center is a value between 0.2 and 0.

6.

6. The sealing device according to claim 3, wherein, The value of the radial width is continuous around the axis.

7. The sealing device according to claim 6, wherein, The radial width increases from one of the pair of ends toward the central portion. The radial width increases from the other of the pair of ends toward the central portion.

8. The sealing device according to claim 4, wherein, The outer peripheral surface is along a cylindrical surface centered on the axis. The inner circumferential surface is along a cylindrical surface having a central axis that is radially offset from the axis.

9. The sealing device according to claim 1, wherein, The sealing device uses a fluid with a viscosity lower than that of water as the object to be sealed.

10. The sealing device according to claim 1, wherein, The sealing device is used to seal the gap between the reciprocating component and the cylindrical hole into which the component is inserted.

Images