A floating seal ring, a floating seal assembly, and a compressor and a positive displacement pump using the same

Abstract

This invention discloses a floating sealing ring, a floating sealing assembly, and a compressor and positive displacement pump using the same. The floating sealing ring body has a semi-saddle-shaped floating longitudinal cross-section. An axial annular groove is provided on the axially inward side of the floating sealing ring body, and a sloping radial annular groove is provided on the top of the floating sealing ring body, extending outward and downward. This invention effectively seals against fluid medium leakage and improves upon traditional sealing methods by changing the variable end-face sealing method from sliding friction to rolling friction. It reduces the wear area, slows down wear, and helps maintain the lifespan of rotary compressors.

Description

Technical Field

[0001] This invention relates to the field of rotary compressors and positive displacement pumps. More specifically, this invention relates to a floating sealing ring, a floating sealing assembly, and compressors and positive displacement pumps using the same. Background Technology

[0002] Rotary compressors or positive displacement pumps are booster devices that combine the functions of both pumps and compressors. They are widely used in production applications such as oil and gas mixed transportation and drainage gas extraction. They are primarily suitable for single or mixed transportation of media such as natural gas, water, and light oil. Features include compact structure, negative pressure pumping, low vibration, low noise, remote setting and monitoring, and unattended operation. The end-face sealing performance of these rotary compressors and positive displacement pumps is a key factor in ensuring their reliable operation. Improper end-face sealing design can lead to increased internal leakage, reducing machine performance and potentially causing compressor or positive displacement pump failure. Existing sealing assemblies suffer from problems such as media flow between the suction and compression chambers, severe wear between the rotor system and wear-resistant liners, and poor end-face sealing of the rotor system. Summary of the Invention

[0003] The purpose of this invention is to provide a floating sealing ring, a floating sealing assembly, and compressors and positive displacement pumps using the same, which effectively seal against fluid media leakage; it also improves upon traditional sealing methods by changing the variable end face sealing method from sliding friction to rolling friction. This reduces the wear area, slows down wear, and helps maintain the lifespan of rotary compressors.

[0004] The technical solution adopted by the present invention to solve this technical problem is: a floating sealing ring, comprising: a floating sealing ring body, the longitudinal section of which is semi-saddle-shaped and floating; wherein, an axial annular groove is provided on the axially inward side of the floating sealing ring body, and a sloping radial annular groove is provided on the top of the floating sealing ring body that slopes outward and downward.

[0005] Preferably, the radial annular groove has a downward sloping structure of 1° from the top of the floating sealing ring body towards the outward side of the floating sealing ring body.

[0006] Preferably, the radial annular groove is provided with a radial sealing ring; and a steel ball is installed in the axial annular groove.

[0007] The present invention also provides a floating seal assembly, comprising: a bearing, a wear-resistant liner, an O-ring, and a floating sealing ring as described in any one of claims 1 to 3;

[0008] An inner conical surface is formed at the radial annular groove on the outer ring of the bearing; the radial annular groove is sealed to the inner conical surface of the outer ring of the bearing through a radial sealing ring; the steel ball is in contact with the outer ring of the bearing; a closed annular space is formed by the radial sealing ring, the floating sealing ring, the O-ring seal and the outer ring of the bearing;

[0009] The bearing outer ring is provided with a flow hole, which is connected to a closed annular space.

[0010] Preferably, there is a gap between the bearing outer ring and the wear-resistant liner.

[0011] Preferably, the lower inner side of the floating sealing ring is provided with an arc-shaped groove for installing the O-ring.

[0012] Preferably, the radial sealing ring is in interference contact with the radial annular groove and the outer ring of the bearing.

[0013] The present invention also provides a rotary compressor, comprising:

[0014] The working chamber is formed by the cylinder block and wear-resistant liners.

[0015] The spindle passes through the working chamber, and the center line of the spindle coincides with the center line of the working chamber. There are N working chambers, where N≥2.

[0016] In a single working chamber, the outer ring of the bearing is eccentrically mounted on the spindle, and the aforementioned floating sealing assembly is provided between the wear-resistant liner and the outer ring of the bearing.

[0017] The present invention also provides a positive displacement pump, including the compressor described above.

[0018] The present invention has at least the following beneficial effects:

[0019] 1) The floating seal ring maintains a certain gap radially between itself and the outer ring of the bearing, allowing it to float freely but not rotate with the outer ring. It can only slide radially and maintain a certain eccentricity with the center of the outer ring under the influence of gravity. When the outer ring rotates, high-pressure oil enters and forms an oil film at the radial gap between the outer ring and the floating seal ring. Due to the wedge force generated by the rotation of the outer ring, a certain oil film pressure is maintained within the oil film, enabling the floating seal ring to automatically maintain alignment with the center of the outer ring. This significantly reduces the gap and effectively seals against fluid leakage.

[0020] 2) The O-ring sealing contact surface width of the floating sealing ring is 0.2–0.3 mm, and the internal tapered gap facilitates the entry of lubricating oil into the sealing surface. Lubricating oil enters the sealing gap through capillary action, centrifugal force during rotation, and the increased internal pressure due to temperature rise within the sealing cavity, forming a thin oil film. This achieves sealing, lubrication, and cooling, while also preventing excessive wear and heat generation on the floating sealing ring's contact surface, which can lead to aging, deformation, and loss of elasticity of the rubber ring. When the working surface of the floating sealing ring wears, the elasticity of the rubber ring can also provide a certain degree of automatic compensation.

[0021] 3) Traditional rotary compressors use sliding friction for end-face sealing. The friction-resistant steel balls installed in the axial grooves of the floating seal ring not only position the wear-resistant liner and bearing outer ring within the working chamber, but also improve upon the traditional sealing method, changing the end-face sealing from sliding friction to rolling friction. This reduces the wear area, slows down wear, and helps maintain the lifespan of the rotary compressor.

[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the floating sealing assembly of the present invention.

[0024] Explanation of reference numerals in the attached drawings: 1 Wear-resistant liner, 2 Bearing outer ring, 3 Steel ball, 4 O-ring seal, 5 Floating seal ring, 6 Flow hole, 7 First sealing part, 8 Second sealing part, 9 Radial annular groove, 10 Step, 11 Arc groove, 12 Sealed annular space. Detailed Implementation

[0025] The present invention will now be described in detail and completely with reference to the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that the technical solutions and features provided in various parts of the present invention, including the following description, can be combined with each other without conflict.

[0026] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific implementation process is as follows:

[0028] The present invention solves the above technical problems by mainly employing the oil film sealing principle to achieve sealing. High-pressure oil exists inside the bearing, and the pressure of this high-pressure oil is equal to the pressure in the exhaust chamber. High-pressure oil leakage occurs through two paths: such as... Figure 1 As shown, ① leakage occurs from seal B+A into the intake chamber, and ② leakage occurs from seal B+C into the annular space. The gap size, oil film filling degree, lubricant viscosity, and rotational speed all significantly affect the oil film sealing performance. To reduce leakage, it is necessary to set a smaller gap (typically tens of micrometers), ensure the gap is fully immersed in lubricant, and select a lubricant with a higher viscosity.

[0029] Example 1

[0030] This invention provides a floating sealing ring 5, comprising: a main body of the floating sealing ring 5, the longitudinal section of which is semi-saddle-shaped and floating; wherein, an axial annular groove is provided on the axially inward side of the main body of the floating sealing ring 5, and a sloping radial annular groove 9 is provided on the top of the main body of the floating sealing ring 5, the radial annular groove 9 and the axial annular groove being located on opposite sides of the main body of the floating sealing ring 5. The floating sealing ring 5 is made of a polymer composite material.

[0031] The semi-saddle-shaped floating structure of the floating sealing ring 5 body includes an integral first sealing part 7 and a second sealing part 8 in the direction from the wear-resistant liner 1 towards the bearing outer ring 2. The first sealing part 7 is an annular structure, and its inward side is provided with a plurality of axial annular grooves. The plurality of axial annular grooves are spaced apart along the outer circumference of the inner side of the first sealing part 7, preferably at equal intervals.

[0032] The radial annular groove 9 is provided with the top of the first sealing part 7 tilted outward and downward. The outer side of the first sealing part 7 forms a step 10 from the bottom to the top, that is, the outer side of the upper part of the first sealing part 7 protrudes more than the outer side of the lower part of the first sealing part 7.

[0033] The second sealing part 8 is a ring-shaped structure, which is coaxially arranged along the inner circumference of the first sealing part 7. An arc-shaped groove 11 is provided on the top of the second sealing part 8 near the inner side for installing the O-ring 4.

[0034] This technical solution may also include the following technical details to better achieve the technical effect: the radial annular groove 9 is a slope-shaped structure with a downward inclination of 1° from the top of the floating sealing ring 5 body to the outward side of the floating sealing ring 5 body.

[0035] This technical solution may also include the following technical details to better achieve the technical effect: the radial annular groove 9 is provided with a radial sealing ring, which seals with the inner conical surface of the outer ring 2 of the bearing through the radial sealing ring. The radial sealing ring is preferably a nitrile rubber O-ring; a steel ball 3 is installed in the axial annular groove, and there is a certain gap between the axial annular groove and the steel ball 3. The steel ball 3 and the axial annular groove are sealed by an oil film.

[0036] Example 2

[0037] like Figure 1 As shown, a floating seal assembly includes: a bearing, a wear-resistant liner 1, an O-ring seal 4, and a floating sealing ring 5 as described in any one of claims 1 to 3;

[0038] The outer ring 2 of the bearing has an inner conical surface at the radial annular groove 9; the radial annular groove 9 is sealed to the inner conical surface of the outer ring 2 of the bearing through a radial sealing ring; the inner conical surface of the outer ring 2 of the bearing has the effect of supporting the radial sealing ring and the main body of the floating sealing ring 5 and keeping them floating in the space; the steel ball 3 is in contact with the outer ring 2 of the bearing; the radial sealing ring, the floating sealing ring 5, the O-ring 4 and the outer ring 2 of the bearing form a closed annular space 12, and the pressure generated pushes the floating sealing ring 5 to produce a gap oil film seal with the wear-resistant liner 1 to achieve end face sealing;

[0039] A flow hole 6 is provided on the outer ring 2 of the bearing, which communicates with the sealed annular space 12. Gas from the intake chamber enters the sealed annular space 12 through the flow hole 6. The high-pressure gas in the cylinder is introduced into the annular space where the steel ball 3 is located by using the flow hole 6 on the outer ring 2 of the bearing. The high-pressure gas presses the floating sealing ring 5 against the wear-resistant liner 1 to form a seal.

[0040] This technical solution may also include the following technical details to better achieve the technical effect: the bearing outer ring 2 and the wear-resistant liner 1 have a gap of 0.05mm, the oil in the high-pressure oil chamber enters from the lower part of the first sealing part 7, and the gap is sealed by the oil film.

[0041] This technical solution may also include the following technical details to better achieve the technical effect: an arc-shaped groove 11 is provided on the lower inner side of the floating sealing ring 5 for installing the O-ring 4.

[0042] This technical solution may also include the following technical details to better achieve the technical effect: the radial sealing ring and the radial annular groove 9 and the bearing outer ring 2 are micro interference contact seal + oil film seal.

[0043] This floating seal assembly mainly uses the oil film sealing principle to achieve sealing, that is, the oil film in the gap blocks the leakage of high-pressure gas through the gap. The gap size, oil film filling degree, lubricating oil viscosity and rotation speed all play an important role in the oil film sealing performance.

[0044] In this embodiment, a method combining sealing and leakage is employed. Sealing is achieved through an oil film seal and the blocking of high-pressure gas leakage through the gap by an oil film within the gap. The gap size, oil film filling degree, lubricant viscosity, and rotational speed all significantly affect the oil film sealing performance. To reduce leakage, it is necessary to set a small gap (typically tens of micrometers), ensure the gap is fully immersed in lubricating oil, and select a lubricating oil with a higher viscosity. Furthermore, applying a higher rotational speed to form a new oil film before the high-pressure gas breaks down the existing oil film is also crucial for reducing oil film seal leakage; for example... Figure 1As shown, seal A is the primary seal, which reduces high-pressure gas leakage into the bearing and also reduces the flow of high-pressure gas from the compression chamber into the intake chamber. Seal B is an auxiliary seal, which re-seales the gas leaking from seal A. If the leakage at seal A is small and the gas leaking into the bearing has no impact on the entire system, seal B is not required. Seals C, D, and E are all introduced to achieve seal B. (Details follow...) Figure 1 As shown, there are a total of 5 seals, and the sealing principle of each seal is as follows:

[0045] (1) Seal A: The outer ring 2 of the bearing and the wear-resistant liner 1 are sealed with an oil film, the gap is 0.1mm, and the axial gap is positioned by steel balls 3;

[0046] (2) Seal B: The floating sealing ring 5 and the wear-resistant liner 1 are in contact and sealed. The high-pressure gas in the cylinder is introduced into the annular space where the steel ball 3 is located by the guide hole of the outer ring 2 of the bearing. The high-pressure gas presses the floating sealing ring 5 onto the wear-resistant liner 1 to form a seal.

[0047] (3) Seal C: Floating sealing ring 5 and bearing outer ring 2, slight interference contact seal + oil film seal;

[0048] (4) Sealing D: Steel ball 3 and axial annular groove, oil film seal;

[0049] (5) Seal E: O-ring 4 and floating sealing ring 5 and bearing outer ring 2, floating contact seal.

[0050] Example 3

[0051] A rotary compressor includes: a working chamber, formed by a cylinder and a wear-resistant liner 1 (the wear-resistant liner 1 is a component of a floating seal assembly). A main shaft passes through the working chamber, with the centerline of the main shaft coinciding with the centerline of the working chamber. There are N working chambers, where N≥2. In each working chamber, a bearing outer ring 2 is eccentrically mounted on the main shaft, and a floating seal assembly is disposed between the wear-resistant liner 1 and the bearing outer ring 2. A flow hole 6 is provided on the bearing outer ring 2, which communicates with a sealed annular space 12. Gas from the suction chamber enters the sealed annular space 12 through the flow hole 6. High-pressure gas from the cylinder is introduced into the annular space containing the steel ball 3 using the flow hole 6 on the bearing outer ring 2. The high-pressure gas presses the floating seal ring 5 against the wear-resistant liner 1 to form a seal.

[0052] The medium is located on the low-pressure side and exited on the high-pressure side. The medium enters from the low-pressure side, and driven by the main shaft, the outer ring 2 of the bearing undergoes a combined motion of revolution and rotation within the working chamber, forming an intake chamber and a compression chamber with continuously changing volumes, thereby compressing the natural gas. The compressed medium is discharged through the high-pressure side. The rotary compressor is existing technology and will not be described further here as it is irrelevant to the innovation of this invention.

[0053] Example 4

[0054] A positive displacement pump, characterized in that it includes the compressor. Driven by the main shaft, the outer ring 2 of the bearing rotates within the working chamber, drawing the medium in from the pump inlet, through the constantly changing volume of the suction chamber and compression chamber within the pump, and the compressed medium flows out from the pump outlet.

[0055] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A floating seal assembly, characterized by, include: Bearings, wear-resistant liners, O-rings, and floating sealing rings; The floating sealing ring includes: a floating sealing ring body, the longitudinal section of which is semi-saddle-shaped and floating; wherein, an axial annular groove is provided on the axially inward side of the floating sealing ring body, and a sloping radial annular groove is provided on the top of the floating sealing ring body that slopes outward and downward; a radial sealing ring is provided in the radial annular groove; and a steel ball is installed in the axial annular groove. An inner conical surface is formed at the radial annular groove on the outer ring of the bearing; the radial annular groove is sealed to the inner conical surface of the outer ring of the bearing through a radial sealing ring; the steel ball is in contact with the outer ring of the bearing; a closed annular space is formed by the radial sealing ring, the floating sealing ring, the O-ring seal and the outer ring of the bearing; The bearing outer ring is provided with a flow hole, which is connected to a closed annular space.

2. The floating seal assembly of claim 1, wherein, There is a gap between the bearing outer ring and the wear-resistant liner.

3. The floating seal assembly of claim 2, wherein, An arc-shaped groove is provided on the lower inner side of the floating sealing ring for installing the O-ring.

4. The floating seal assembly of claim 2, wherein, The radial sealing ring has an interference fit seal with the radial annular groove and the outer ring of the bearing.

5. A rotary compressor, characterized in that, include: The working chamber is enclosed by the cylinder block and wear-resistant liners; The spindle passes through the working chamber, and the center line of the spindle coincides with the center line of the working chamber. There are N working chambers, where N≥2. In a single working chamber, the outer ring of the bearing is eccentrically fitted onto the spindle, and a floating seal assembly as described in any one of claims 2 to 4 is provided between the wear-resistant liner and the outer ring of the bearing.

6. A positive displacement pump, characterized in that, Includes the compressor as described in claim 5.

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