Floating ring seal with static pressure throttling function

Abstract

The invention discloses a floating ring seal with a static pressure throttling function. The floating ring seal comprises a floating ring, an elastic assembly and a shell with a left gland and a right gland. The floating ring is located in the shell and has a gap therebetween, and the inner diameter of the floating ring is in clearance fit with the rotor; the left end of the floating ring is conical, and a wedge-shaped gap is formed between the conical part and the shell; the right gland enables the left end face of the floating ring to be attached to the left gland through an elastic assembly. A plurality of small throttling holes are formed in the outer shell in the circumferential direction, a plurality of oil cavities are formed in the inner wall of the outer shell, and the small throttling holes, the oil cavities and the gaps are communicated. According to the invention, the floating ring can effectively improve the abrasion condition of the floating ring caused by insufficient rotating speed by virtue of a fluid static pressure effect at the initial rotating stage, better lubrication and floating ring self-adjusting functions are realized, and the whole floating ring is always in a lubricating substance no matter whether oil lubrication or gas lubrication is selected, so that the friction coefficient is reduced, and the working efficiency of a machine is improved; and the integral floating ring is adopted in structure, so that the processing time is shortened, and the installation cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical engineering seals, and particularly relates to a floating ring seal with static pressure throttling, which is a non-contact seal and can be applied to various rotating machines (engines, steam turbines, compressors, etc.) to reduce axial leakage. Background Art

[0002] Floating ring seals are simple, non-contact seals composed of a ring, pin, spring, and other components. They offer advantages such as compact size, high-temperature resistance, and low leakage, making them widely used in various rotating machinery, such as rocket engine turbopumps and high-speed aircraft engines. As equipment evolves toward higher speeds and higher power, the performance requirements for sealing components are becoming increasingly stringent. Consequently, new floating ring seal structures have been proposed to address specific operating conditions.

[0003] Patent CN115370748A discloses a petal-type floating ring seal with a throttling orifice. The floating ring seal consists of multiple petal sealing segments with dynamic and static pressure grooves on their inner surfaces. This invention enhances the dynamic and static pressure effect by creating circumferential dynamic and static pressure grooves, achieving both axial sealing and lubrication. However, because the grooves are only on the inner surface of the floating ring, the outer surface of the floating ring is susceptible to friction with the outer casing at low rotational speeds, significantly negatively impacting the stable operation of the floating ring and the sealing properties of the device.

[0004] Patent CN211288754U discloses a floating ring seal device with an axially arranged "high-pressure floating ring" and three "low-pressure floating rings." The device prevents leakage of high-pressure media to low-pressure media by sealing lubricating oil between the axially arranged "high-pressure floating ring" and a rotating shaft with spiral grooves. The throttling effect of the three "low-pressure floating rings" and the hydraulic reverse thrust of the spiral grooves reduce gas and sealing oil leakage. This invention uses an inner sleeve to prevent friction between the floating ring and the outer shell, but ignores the contact friction between the floating ring and the inner sleeve. Furthermore, due to the multiple floating rings, the operating state of each floating ring cannot be guaranteed to be consistent, and friction between the floating ring and the inner sleeve further exacerbates this instability.

[0005] Patent CN118499132A discloses a floating ring seal structure for pumping with cambered microgrooves. This structure improves upon the traditional floating ring seal by designing a rotating ring that rotates with the rotor. Cambered microgrooves between the rotating ring and its floating assembly provide sealing. Dynamic pressure grooves are defined on the radially outer wall of the rotating ring, with the end face open toward the low-pressure side. The addition of these grooves effectively enhances the dynamic pressure effect of the fluid, reduces friction between the rotating ring and the floating assembly, and improves the operating stability of the rotating ring. However, at low speeds, the friction between the floating assembly and the housing, as well as the supporting force of the air film between the rotating ring and the floating ring, is insufficient to balance the gravity acting on the floating assembly. This can lead to hard collisions between the floating assembly and the housing, thus affecting the performance of the entire sealing system.

[0006] Patent CN116379159A discloses a split radial seal with bilaterally symmetrical grooved conical surfaces. The conical body creates a converging gap, generating a dynamic pressure effect to prevent axial leakage of the sealing fluid. Because the inner ring of this invention has a transition or interference fit with the shaft, rotor vibration at high speeds can easily cause friction between the outer surface of the inner ring and the inner surface of the outer ring, affecting the stability of the seal.

[0007] Patent CN106838324A discloses a hybrid static-dynamic floating ring seal, suitable for rotating shaft sealing. It primarily consists of a floating ring and two different types of sealing rings. Oil inlet and drain holes are provided on the floating ring to ensure the circulation of the sealing and lubricating media within the two-stage seal, thereby improving the sealing performance of the device. Rotating rotors drive the flow of the media, forming a fluid film with a certain rigidity, reducing friction between the rotor and the floating ring. In this invention, static pressure is introduced through a throttle orifice, which gradually decreases with increasing rotor speed. Because both static and dynamic pressure effects are unstable, the floating ring rubs against the rotor during the initial stages of rotation, affecting the stable operation of the sealing device.

[0008] Patent CN116181909A discloses a petal-type floating ring seal structure with a circumferentially converging wedge-shaped microtexture. The floating ring seal comprises multiple sealing ring petals, characterized by circumferential relief grooves, axial relief grooves, and wedge-shaped microtexture. The converging wedge-shaped microtexture enhances the circumferential hydrodynamic pressure effect, reduces wear on the floating ring petals, and extends the service life of the floating ring seal. During the initial rotational phase, insufficient hydrodynamic pressure can cause friction between the floating ring petals and the rotor, impacting normal operation. Static pressure can be introduced between the floating ring petals and the housing to mitigate this effect at lower rotational speeds.

[0009] Patent CN115126877A discloses a low-leakage, long-life floating ring seal. Its floating ring seal structure features a herringbone-shaped metal foil evenly spaced along the outer circumference of the floating ring, preventing friction between the floating ring and the seal seat and extending the seal's service life. In the axial direction, forces act between the elastic metal sealing ring, the end face of the floating ring, and the end face of the seal seat, preventing the floating ring from achieving its floating characteristics. At low speeds, this results in a weak dynamic pressure effect between the floating ring and the rotor, making it insufficient for sealing the medium.

[0010] In summary, existing floating ring seals suffer from two common issues: One is unstable operation caused by friction between the floating ring and the housing at low rotational speeds; the other is rubbing caused by radial runout during stable operation. These two issues are common in rotating equipment, resulting in significant costs for equipment processing, overhaul, maintenance, and parts replacement. Therefore, this research aims to address these issues by addressing the friction and collision between the floating ring and the housing. Summary of the Invention

[0011] To overcome the shortcomings of the prior art, reduce collisions and friction in the seal, and simplify the floating ring seal structure, the present invention provides a floating ring seal with static pressure throttling. By providing evenly distributed oil chambers and throttling holes on the inner and outer circumferential surfaces of the housing, a static pressure fluid is introduced between the outer surface of the floating ring and the housing to create a static pressure effect. This effectively reduces collisions and friction between the floating ring and the housing. Furthermore, the combined effects of dynamic and static pressure provide support for the floating ring structure, ensuring the stability of the gap between the floating ring and the housing, preventing collisions and friction, and thereby improving the operational stability of the floating ring and its overall sealing performance.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is:

[0013] A floating ring seal with static pressure throttling comprises a floating ring, an elastic component and a housing with a left gland and a right gland; the floating ring is located in the housing with a gap between the two, and the inner diameter of the floating ring matches the rotor gap; the left end of the floating ring is conical, and a wedge-shaped gap is formed between the conical portion and the housing; the right gland enables the left end face of the floating ring to fit with the left gland via the elastic component; a plurality of throttling holes are opened circumferentially on the housing, and a plurality of oil chambers are opened on the inner wall of the housing, and the throttling holes, oil chambers and gaps are connected.

[0014] The present invention forms a closed sealing structure through the above structure. The floating ring has a certain floating space, and the elastic component ensures the axial stability of the floating ring.

[0015] In one embodiment, the floating ring body is hollow cylindrical, with a left end that is hollow conical, and the end surface of the smallest end of the cone serving as its right end surface. The rotor is located within the hollow portion of the floating ring, forming a gap with the floating ring to create a micro-gap fluid space. This ensures the generation of a fluid dynamic pressure effect between the rotor and the floating ring during high-speed operation, thereby achieving radial floating characteristics during operation of the floating ring. The gap is formed between the outer wall of the cylindrical portion and the inner wall of the housing, while the wedge-shaped gap is formed between the outer wall of the conical portion and the inner wall of the housing. Both the gap and the wedge-shaped gap are micron-sized, forming a flow channel for the static pressure fluid.

[0016] In one embodiment, a left end surface of the floating ring is provided with a plurality of grooves.

[0017] In one embodiment, the elastic component includes a retaining ring and a spring. The inner wall of the outer shell is provided with a circumferential inner groove. The retaining ring is a cylinder with a through hole, which is arranged in the circumferential inner groove. It is radially clearance-fitted with the outer shell and the rotor, and is axially located between the floating ring and the spring. The axial stability of the floating ring is ensured by the action of the spring's adaptive compensation force. The right end of the spring is welded to the right pressure cover.

[0018] According to this structure, since the retaining ring is located between the floating ring and the spring, and has a clearance fit with the outer shell and the rotor in the radial direction, the floating space of the floating ring can be guaranteed. The floating ring and the retaining ring are coaxially matched, and the adaptive compensation force of the spring is used to ensure the axial stability of the floating ring. The spring is welded to the right pressure cover, and the right pressure cover is fixed to the outer shell by screws.

[0019] In one embodiment, the circumferential inner groove is located 1 / 3 to 1 / 4 of the way to the left axially from the right end of the inner wall of the housing. The groove depth is 0.1 to 0.2 times the diameter of the retaining ring, and the axial length is 1.1 to 1.3 times the axial length of the retaining ring. Due to the dynamic pressure effect, a thick film with a certain degree of rigidity is generated between the inner wall of the floating ring and the rotor, preventing fluid from flowing from the high-pressure side to the low-pressure side, thereby achieving axial sealing. Simultaneously, the floating ring seal and the retaining ring are compressed, and the generated axial force is borne by a spring supporting the back of the retaining ring. The compression of the spring is less than the axial length of the circumferential inner groove, ensuring that the retaining ring has a certain axial displacement. For example, the retaining ring diameter is 0.8 to 0.9 times the outer diameter of the housing, and the axial length of the retaining ring is 5 to 15 mm.

[0020] In one embodiment, the housing is a hollow cylindrical structure with an outer diameter determined by the empirical rolling bearing formula D2 = 1.1D1 + 5, where D2 is the outer diameter of the housing and D1 is the inner diameter. The interior of the housing is a circular cavity that forms a clearance fit with the floating ring, meeting clearance requirements. Circumferential recesses are defined on both the left and right end faces of the housing for secure connection to the left and right glands, respectively. The outer diameter of the recesses is 0.8 to 0.9 times the diameter of the housing and has a depth of 5 to 15 mm, matching the thickness of the glands connected by screws, ensuring radial alignment of the glands with the housing end faces after installation.

[0021] In one embodiment, the axial length of the housing is 1.2 to 1.8 times the axial length of the floating ring. A circumferential outer groove serving as an oil inlet groove is defined at the axially symmetrical center of the housing's outer wall. The throttling orifices are disposed within the circumferential outer groove, communicating with the interior of the housing through the throttling orifices to achieve a continuous supply of lubricating medium. The depth of the circumferential outer groove is 1 / 5 to 1 / 3 of the housing's wall thickness. The oil chambers are defined on the axially symmetrical plane of the housing's inner wall and are evenly distributed circumferentially. The throttling orifices are connected to the oil chambers in a one-to-one correspondence, and the throttling orifices are radial holes.

[0022] In one embodiment, the number of the oil chambers is 4 to 10 and they are evenly distributed in a single row along the circumference. The radial depth of the oil chamber is in the millimeter range. The axial cross-section of the oil chamber is a rectangular cross-section structure. The axial length is 0.3 to 0.7 times the width of the floating ring. The ratio of the circumferential length to the axial length is 0.8 to 1.2. The depth of the oil chamber is l1 is the radial length of the throttling hole.

[0023] In one embodiment, the diameter of the throttling hole is 2 to 6 mm, and it supplies static pressure fluid and realizes the throttling function; the radial length l1 is 0.2 to 0.8 times the difference between the inner and outer diameters of the shell; the throttling hole supplies static pressure fluid and realizes the throttling function, and its flow rate is determined by the throttling equation Determine, Q is the flow rate of a single small hole, C d is the displacement coefficient, A is the cross-sectional area of the orifice, ρ is the fluid density, P1 is the orifice inlet pressure, and P2 is the orifice outlet pressure.

[0024] In one embodiment, the hydrostatic pressure effect floating ring seal is achieved by providing an oil chamber below an external oil supply throttle in the gap between the floating ring and the housing. Simultaneously, when the floating ring deflects radially in a certain direction during operation, the corresponding oil chamber generates a hydrostatic pressure effect to resist such deflection, thereby preventing friction between the floating ring and the housing. Furthermore, the fluid formed between the inner side of the floating ring and the rotor generates a dynamic pressure effect when the rotor rotates, resulting in a pressure gradient in the fluid. This pressure gradient is balanced by the forces acting on the spring and the high and low pressure sides, thereby achieving the axial floating characteristics of the floating ring.

[0025] In one embodiment, the spring is an ordinary cylindrical spring, which is fixed to the right gland by welding. There are an even number of springs, 4 to 10 in number, and the bottom is evenly fixed to the right gland around the circumference. The top of the spring presses against the retaining ring to bear the possible axial force of the seal and retaining ring during operation.

[0026] In one embodiment, the left and right glands are cylinders with through holes and several bolt holes near the outer diameter. The inner diameter thereof is loosely matched with the inner diameter of the rotor, and the number of bolt holes is 6 to 12. The diameter of the small hole is determined by the diameter of the selected screw, and the glands are fixed by ordinary bolts. The diameter of the gland is consistent with the diameter of the circumferential recess at one end of the housing, and the thickness is consistent with the depth of the recess.

[0027] Compared with the prior art, the present invention has the following beneficial effects: by improving the existing integral floating ring seal structure, the original floating ring and fixed ring are in fixed contact with each other, and then it is changed to a floating ring seal structure with a throttling hole. This allows the floating ring to take advantage of the hydrostatic effect in the initial stage of rotation, effectively improving the wear of the floating ring caused by insufficient rotation speed, and achieving better lubrication and floating ring self-adjustment function. Regardless of whether oil lubrication or gas lubrication is selected, the entire floating ring is always in the lubricating material, which reduces the friction coefficient and improves the working efficiency of the machine. The use of an integral floating ring structure reduces processing time and installation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the integral floating ring of the present invention.

[0029] Figure 2 It is a schematic diagram of the axial cross section of the integral floating ring of the present invention.

[0030] Figure 3 It is a schematic diagram of the floating ring structure of the present invention.

[0031] Figure 4 It is an axial cross-sectional view of the housing of the present invention.

[0032] Figure 5 It is a schematic diagram of the retaining ring structure of the present invention.

[0033] Figure 6 It is a schematic diagram of the spring structure of the present invention.

[0034] Figure 7 It is a schematic diagram of the gland structure of the present invention. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0036] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 As shown, the present invention is a floating ring seal with static pressure throttling, which primarily comprises a housing 1, a floating ring 2, an elastic assembly, and left and right glands 51, 52. The left and right glands 51, 52 are mounted on the left and right ends of the housing 1 via screws 7, forming an enclosed space. The housing 1 is hollow cylindrical, with its left and right ends representing the axial ends of the cylinder.

[0037] In this embodiment of the present invention, the elastic assembly primarily consists of a retaining ring 3 and a spring 4. Other similar elastic structures may also be used in this invention. The floating ring 2 is composed of a hollow cylindrical portion connected to a conical portion. For ease of description, the present invention, with reference to the accompanying drawings, assumes that the conical portion is to the left of the cylindrical portion. In this invention, the terms "left" and "right" are used for ease of description and do not limit the structure of the present invention. The cross-sectional area of the right end face of the conical portion is smaller than that of the left end face, which is equal to the cross-sectional area of the cylindrical portion. Therefore, the right end face of the conical portion represents the left end face 2-1 of the floating ring 2 of this invention.

[0038] The housing 1 is fixed to the support base. During the initial stage of rotation, the left end surface 2-1 of the floating ring 2 and the inner end surface of the left gland 51 are in contact with each other due to the action of the elastic component. Furthermore, a radial gap 8-2 is formed between the cylindrical portion and the inner wall of the housing 1, while a radial wedge-shaped gap 8-1 is formed between the conical portion and the inner wall of the housing 1. The term "wedge-shaped" here refers to a wedge-shaped cross-section along the central axis.

[0039] In the present invention, the retaining ring 3 is located between the floating ring 2 and the spring 4, and is arranged in the circumferential inner groove 1-4 inside the shell 1. The spring 4 and the floating ring 2 work together to achieve clearance fit with the shell 1, wherein the circumferential inner groove 1-4 is an annular groove.

[0040] In the present invention, the spring 4 can be fixed to the right gland 52 by welding. The number of the spring 4 can be multiple and evenly distributed along the circumference of the right gland 52. The radial distance between the center of a single spring 4 and the center of the right gland 52 is set to 0.4 to 0.5 times the outer diameter of the right gland 52. The left gland 51 and the right gland 52 are both fixed to the housing 1 by screws.

[0041] According to the structure of the present invention, the circumferential recesses 1-5 at both ends of the housing 1 are provided with threaded holes 1-3, which are threadedly connected to the corresponding glands via threaded holes 1-3 and screws 7. During use, lubricating fluid is introduced through the throttling orifice 6. Due to the throttling effect, a lubricating oil film is formed in the gap 8-2. As the fluid continues to flow into the wedge-shaped gap 8-1, the wedge-shaped gap 8-1 causes the fluid to experience radial pressure changes, causing the floating ring 2 to move in the axial direction. The lubricating fluid enters the groove 2-2 on the left end surface 2-1, which can be a rectangular groove. Due to the hydrodynamic effect, the fluid pressure in groove 2-2 increases, increasing the axial force acting on floating ring 2. At this time, spring 4 provides a compensating force, keeping floating ring 2 in a stable axial floating state. Some lubricating fluid flows into the gap between floating ring 2 and the rotor. This fluid rotates with the shaft and causes axial floating of floating ring 2. As the rotor speed increases, the hydrodynamic effect intensifies, forming an oil film of a certain thickness between floating ring 2 and the rotor. This reduces friction between the two and generates a radial supporting force, causing floating ring 2 to move radially. The oil film in gap 8-2 is squeezed, creating a mixed dynamic and static pressure effect. The increased fluid pressure exerts a compensating force on floating ring 2 in the radial direction, maintaining a stable radial floating state. The sealed fluid is located at both axial ends of the integral floating ring seal of the present invention. The oil film in the gap between floating ring 2 and the rotor prevents the sealing fluid from passing through, achieving axial sealing.

[0042] In some embodiments of the present invention, the circumferential outer groove 1-1 is a single groove, and the oil chamber 1-2 is a single-cavity structure evenly spaced along the circumference. Both are located at the axial center of the housing 1. The throttling holes 6 are arranged in a single row of multiple holes on the same circumference. The number of throttling holes 6 can be designed according to specific sealing conditions and structural parameters. All throttling holes 6 are evenly distributed along the circumference. The circumferential inner grooves 1-4 are set according to the axial length of the floating ring 2.

[0043] The circumferential outer groove 1-1 and the single-row throttling holes 6 structure adopted in this embodiment have a simple process flow. At the same time, the circumferential outer groove 1-1 and the throttling holes 6 can realize the pressure reduction function, and together with the wedge-shaped gap 8-1 between the left end surface 2-1 of the floating ring 2 and the outer shell 1, further enhance the static pressure effect, thereby reducing the wear of the floating ring 2 and the outer shell 1.

[0044] In some embodiments of the present invention, the groove depth (radial direction) of the circumferential outer groove 1-1 and the cavity depth (radial direction) of the circumferential oil cavity 1-2 are in the millimeter order, ranging from 3 to 10 mm. The axial cross-section of the circumferential outer groove 1-1 is rectangular, and the width (axial length) is 1 / 5 to 1 / 7 of the axial length of the floating ring 2. The oil cavity 1-2 is a single groove structure, with an axial cross-section of a rectangle and a width (axial length) of 1 / 4 to 1 / 3 of the axial length of the floating ring 2. The axial length of the floating ring 2 should be less than or equal to 1 / 3 of the axial length of the housing 1 (including the wall thickness). The chamfer angle of the tapered portion of the floating ring 2 is set between 5 and 20 degrees. The throttling hole 6 radially connects the circumferential outer groove 1-1 and the oil cavity 1-2. 2. The length (radial direction) is 0.3 to 0.5 times the thickness of the shell wall, and the diameter of the small hole is 1 / 2 to 1 / 4 of the width of the circumferential outer groove 1-1; the wall thickness of the shell 1 (radial length of the shell) is 1 / 2 of the difference between the outer diameter and the inner diameter of the shell, and is also the sum of the groove depth of the circumferential outer groove 1-1, the length of the throttling hole 6 and the length (radial direction) of the oil chamber 1-2. The distance between the two side symmetry surfaces of the circumferential inner groove 1-4 and the end face of the shell 1 is approximately 0.8 to 1.2 times the axial length of the floating ring 2. The groove depth of the circumferential inner groove 1-4 is at least 0.1 times the diameter of the retaining ring 3 and does not exceed the shell wall thickness. The axial length of the circumferential inner groove 1-4 is 1.2 to 1.5 times the axial length of the retaining ring 3. The circumferential recesses 1-5 on both sides of the housing are 5-8 mm deep, with an outer diameter of 0.9-0.95 times the outer diameter of the housing 1. The difference between the inner and outer diameters of the circumferential recesses 1-5 is greater than or equal to 6 mm. The threaded holes 1-3 are 6-8 mm deep and evenly distributed along the circumference, preferably numbering 4-6. The outer diameter of the floating ring 2 is 0.9-0.95 times the diameter of the housing cavity, the inner diameter of the floating ring is 1.05-1.1 times the diameter of the rotor, and the axial length of the floating ring is 0.6-0.7 times the axial length of the housing cavity.

[0045] The axial length of the retaining ring 3 is 1 to 1.1 times the axial length of the floating ring 2, the outer diameter of the retaining ring 3 is 1.1 to 1.2 times the outer diameter of the floating ring 2, and is less than 0.9 times the inner diameter of the shell 1. The inner diameter of the retaining ring 3 is 1.2 to 1.3 times the inner diameter of the floating ring 2, and the ratio of the outer diameter of the retaining ring 3 to the axial length is 18 to 22.

[0046] The left and right glands 51 and 52 have identical structures, with an outer diameter 0.8 to 0.9 times that of the outer diameter of the housing, and a millimeter-level clearance between the gland and the circumferential recess 1-5. The gland's inner diameter is 1.2 to 1.3 times that of the floating ring 2, and the gland's outer diameter to axial length ratio is 16 to 18. The gland utilizes an annular plate structure, with through-holes 5-2 at both ends having a diameter of 1.05 to 1.1 times the rotor diameter to ensure smooth passage of the rotor. Several circular recesses 5-4 are circumferentially defined on one end surface 5-3, each 2 to 3 mm deep and 1.2 to 1.5 times the diameter of the screw 7. Screw holes 5-1 are located within the circular recesses 5-4, with a depth equal to or greater than the difference between the gland's axial length and the depth of the circular recesses 5-4, not less than 2 mm.

[0047] The following are two specific embodiments of the present invention.

[0048] Example 1

[0049] In order to meet the requirement of zero friction under high-speed and high-pressure working conditions, a floating ring seal with static pressure throttling is proposed, and the structure is further described in conjunction with the following figures.

[0050] like Figure 1 、 Figure 2 As shown, the integrated floating ring seal structure of this embodiment mainly consists of a housing 1, a floating ring 2, a retaining ring 3, a spring 4, a gland 5 and screws 7, wherein:

[0051] The shell 1 is a hollow cylindrical structure with symmetrical concave platforms. Figure 4 As shown, the housing comprises a circumferential outer groove 1-1 arranged along an axially symmetrical cross-section on the outer surface, a throttling orifice 6, an oil cavity 1-2 with a circumferential single groove structure arranged along an axially symmetrical cross-section on the inner surface, and a plurality of threaded holes 1-3. In this embodiment, the housing has an outer diameter of 106 mm, an inner diameter of 92 mm, a through-hole diameter of 51 mm, a radial wall thickness of 15 mm, an axial length of 60 mm, a symmetrical concave platform diameter of 98 mm, a platform depth of 3 mm, a threaded hole diameter of 2 mm, and a hole depth of 4 mm.

[0052] The circumferential outer groove 1-1 is arranged along the outer circumference of the housing 1, as shown in FIG. Figure 2 As shown, the groove center is set on the axisymmetric cross-section at both ends of the shell, and evenly distributed throttling holes 6 are set in the circumferential outer groove 1-1; the circumferential outer groove 1-1 has a groove depth of 3mm, a rectangular axial cross-section, and an axial length of 8mm.

[0053] The circumferential inner grooves 1-4 are arranged along the inner circumference of the housing 1, as shown in FIG. Figure 4 As shown, the distance between the symmetrical surfaces on both sides and the left and right glands is 45 mm, the groove depth is 9 mm, and the axial length of the groove is 5 mm;

[0054] The throttling hole 6 is provided in the circumferential outer groove 1-1, as shown in FIG. Figure 2 As shown, the center of the small hole is located on the axially symmetrical cross-section at both ends of the shell 1, and the throttling holes 6 are connected to the circumferential outer groove 1-1 and the oil chamber 1-2 respectively; the number of throttling holes 6 is 12, and the interval between two adjacent throttling holes 6 is 30 degrees, and the radial length is 6 mm.

[0055] The oil chamber 1-2 is arranged along the circumference of the inner surface of the housing 1, as shown in FIG. Figure 2 、 Figure 4As shown, its upper end is connected to the throttling hole 6, and the lower end forms a gap 8-2 and a wedge-shaped gap 8-1 with the floating ring 2. The center line of the oil chamber is located on the axisymmetric cross-section at both ends of the housing 1, and the interval between two adjacent oil chambers is 30 degrees; the radial cavity depth of the oil chamber 1-2 is 6mm, the radial cross-section of the oil chamber is square, and the length is 15mm.

[0056] The floating ring 2 is a hollow cylinder with a through hole and a chamfered end. Figure 3 As shown, the left end surface 2-1 is provided with rectangular grooves 2-2 evenly distributed in the circumferential direction. The chamfer angle of the tapered portion of the floating ring 2 is 20°, the groove 2-2 is 1mm deep, the groove length is uniformly 3mm, and the interval between two adjacent grooves is 30 degrees. The outer diameter of the floating ring 2 is 88mm, the axial length is 45mm, and the floating ring 2 and the rotor are clearance-fitted.

[0057] The retaining ring 3 is an annular cylinder, such as Figure 5 As shown, one end face 4-1 contacts the axial end face of the floating ring and the axial end face of the circumferential inner groove 1-4, and the other end face directly contacts the spring 4. The outer diameter of the retaining ring is 90 mm, the inner diameter is 54 mm, the axial length is 4 mm, and the diameter of the retaining ring hole 4-2 is 1.05 to 1.1 times the diameter of the rotor to ensure that the rotor can pass without interference.

[0058] Spring 4 Figure 6 As shown, one end face is in direct contact with the retaining ring 3, and the other end face is welded to the right pressure cover 52 and is evenly distributed along the circumference. The center of the spring is 20 mm away from the center of the axis, and the interval between adjacent springs is 90 degrees. The original axial length of the spring is 25 mm, and the original radial length is 20 mm.

[0059] The gland is an annular cylinder with a through hole and a threaded hole. Figure 7 As shown, one end face 5-3 is in direct contact with the circumferential inner groove 1-4 and is connected to the screw 7 through the screw hole 5-1. The screw holes 5-1 are evenly distributed along the circumference, there are 6 screw holes, and the interval between two adjacent screw holes is 60 degrees. The outer diameter of the pressure cover is 97mm, the inner diameter is 51mm, the axial length is 3mm, the screw hole diameter is 3mm, and the hole depth is 3mm.

[0060] The thread diameter of the screw 7 is 2.5 mm and the axial length is 6 mm.

[0061] In order to maximize the static pressure effect between the floating ring and the shell and meet the goal of zero friction under high speed and high pressure, according to the throttling equation The cross-sectional area of the small hole should be smaller when the inlet flow rate remains unchanged, and 3 mm is used in this embodiment.

[0062] Example 2

[0063] For working conditions with low speed and pressure, this embodiment proposes a floating ring seal with static pressure throttling, which is further described in detail with reference to the accompanying drawings.

[0064] like Figure 1 、 Figure 2 As shown, the embodiment of the present invention is an integrated floating ring seal structure composed of a housing 1, a floating ring 2, a retaining ring 3, a spring 4, a gland 5 and screws 7, wherein:

[0065] The structures and structural parameters of the floating ring 2, retaining ring 3, spring 4, gland 5 and screw 7 are the same as those of the embodiment 1.

[0066] Shell 1, its structure is as follows Figure 2 、 Figure 4 As shown, the circumferential outer groove 1-1, the symmetrical concave platform 1-5, the oil cavity 1-2, the throttling hole 6, and the threaded hole 1-3 are also provided. Except for the throttling hole 6, the structure is the same as that of the embodiment 1, and only the structural parameters are adjusted.

[0067] Since the pressure between the floating ring and the shaft is small and the speed is low, it is not enough to support the floating ring. Therefore, it is necessary to increase the pressure between the floating ring and the shell appropriately. According to the throttling equation The cross-sectional area of the small hole should satisfy the requirement of constant inlet flow rate, and a larger value should be taken, which is 5 mm in this embodiment.

Claims

1. A floating ring seal with static pressure throttling, characterized in that: The invention comprises a floating ring (2), an elastic component and a housing (1) with a left pressure cover (51) and a right pressure cover (52); the floating ring (2) is located in the housing (1) and a gap (8-2) exists between the two, and the inner diameter of the floating ring (2) matches the rotor gap; the left end of the floating ring (2) is conical, and a wedge-shaped gap (8-1) is formed between the conical part and the housing (1); the right pressure cover (52) enables the left end face (2-1) of the floating ring (2) to fit with the left pressure cover (51) through the elastic component; a plurality of throttling holes (6) are opened on the housing (1) along the circumferential direction, and a plurality of oil chambers (1-2) are opened on the inner wall of the housing (1); the throttling holes (6), the oil chambers (1-2) and the gap (8-2) are communicated.

2. The floating ring seal with static pressure throttling according to claim 1, characterized in that: The floating ring (2) has a hollow cylindrical body and a hollow conical left end. The rotor is located in the hollow part of the floating ring (2) and forms a clearance fit with the floating ring (2). The gap (8-2) is formed between the outer wall of the cylindrical part and the inner wall of the outer shell (1), and the wedge-shaped gap (8-1) is formed between the outer wall of the conical part and the inner wall of the outer shell (1). Both the gap (8-2) and the wedge-shaped gap (8-1) are micrometer-sized.

3. The floating ring seal with static pressure throttling according to claim 1 or 2, characterized in that: The left end surface (2-1) of the floating ring (2) is provided with a plurality of grooves (2-2).

4. The floating ring seal with static pressure throttling according to claim 1, characterized in that: The elastic component includes a retaining ring (3) and a spring (4). The inner wall of the housing (1) is provided with a circumferential inner groove (1-4). The retaining ring (3) is arranged in the circumferential inner groove (1-4). It is clearance-matched with the housing (1) and the rotor in the radial direction. It is located between the floating ring (2) and the spring (4) in the axial direction. The axial stability of the floating ring (2) is ensured by the action of the adaptive compensation force of the spring (4). The right end of the spring (4) is welded to the right pressure cover (52).

5. The floating ring seal with static pressure throttling according to claim 4, characterized in that: The circumferential inner groove (1-4) is opened at a position 1 / 3 to 1 / 4 axially to the left of the right end of the inner wall of the housing (1); the groove depth is 0.1 to 0.2 times the diameter of the retaining ring, and the axial length is 1.1 to 1.3 times the axial length of the retaining ring. The compression amount of the spring (4) is less than the axial length of the circumferential inner groove (1-4), ensuring that the retaining ring (3) has a certain axial displacement.

6. The floating ring seal with static pressure throttling according to claim 1, characterized in that: The shell (1) is a hollow cylindrical structure, and both end surfaces thereof are provided with circumferential concave platforms (1-5) for respectively fixedly connecting with the left gland (51) and the right gland (52); the axial length of the shell (1) is 1.2 to 1.8 times the axial length of the floating ring (2).

7. The floating ring seal with static pressure throttling according to claim 1, characterized in that: A circumferential outer groove (1-1) is provided at the axially symmetrical center position of the outer wall of the housing (1) as an oil inlet groove, and the throttling holes (6) are arranged in the circumferential outer groove (1-1). The groove depth of the circumferential outer groove (1-1) is 1 / 5 to 1 / 3 of the wall thickness of the housing (1); the oil chambers (1-2) are provided on the axially symmetrical surface of the inner wall of the housing (1) and are evenly distributed along the circumference. The throttling holes (6) are connected to the oil chambers (1-2) in a one-to-one correspondence, and the throttling holes (6) are radial holes.

8. The floating ring seal with static pressure throttling according to claim 1, characterized in that: The number of the oil chambers (1-2) is 4 to 10 and they are evenly distributed in a single row along the circumferential direction. The depth of the oil chamber along the radial direction is in the millimeter range. The axial cross section of the oil chamber (1-2) is a rectangular cross section structure. The axial length is 0.3 to 0.7 times the width of the floating ring. The ratio of the circumferential length to the axial length is 0.8 to 1.

2. The depth of the oil chamber is l1 is the radial length of the throttling hole (6).

9. The floating ring seal with static pressure throttling according to claim 1, characterized in that: The throttling hole (6) has a diameter of 2 to 6 mm and a radial length l1 of 0.2 to 0.8 times the difference between the inner and outer diameters of the housing (1); the throttling hole (6) supplies static pressure fluid and realizes the throttling function, and its flow rate is determined by the throttling equation Determine, Q is the flow rate of a single small hole, C d is the displacement coefficient, A is the cross-sectional area of the orifice, ρ is the fluid density, P1 is the orifice inlet pressure, and P2 is the orifice outlet pressure.

10. The floating ring seal with static pressure throttling according to claim 1, characterized in that: The fluid formed between the inner side of the floating ring (2) and the rotor generates a dynamic pressure effect when the rotor rotates, and the pressure gradient of the fluid is balanced with the action forces of the spring assembly and the high and low pressure sides, thereby realizing the axial floating characteristics of the floating ring.

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