A water pump sealing structure of an etching apparatus

Abstract

The application relates to the technical field of water pump sealing, in particular to a water pump sealing structure of an etching equipment, which comprises a fixed sleeve fixed to a flange seat, wherein a primary sealing sleeve assembly rotating with a motor shaft, a first secondary sealing element forming a labyrinth seal with the motor shaft and a second secondary sealing element are sequentially arranged in the fixed sleeve from the side close to the pump to the outside along the axial direction. The primary sealing sleeve assembly is used for actively throwing away liquid; the first secondary sealing element reduces the pressure of acid gas and fluid through the labyrinth effect; the sealing lip of the second secondary sealing element faces the inside of the pump, and self-tight sealing is formed by using medium pressure to complete the final plugging. Through the above-mentioned three-stage progressive collaborative protection, the coexistence problem of water leakage and gas emission is effectively solved, the equipment corrosion is slowed down to a certain extent, and the reliability and service life of the sealing are improved.

Description

Technical Field

[0001] This utility model relates to the field of mechanical seal technology, and in particular to a water pump sealing structure for etching equipment. Background Technology

[0002] In wet etching processes in industries such as semiconductors and PCBs, etching water pumps are used to transport highly corrosive liquids. The seal between the motor shaft and the pump body flange is crucial for ensuring stable equipment operation and a safe working environment. Currently, this scenario commonly uses simple skeleton oil seals. Skeleton oil seals primarily rely on their elastic lips to maintain contact with the rotating motor shaft to prevent liquid leakage.

[0003] However, under etching conditions, skeleton oil seals have inherent defects: First, high-speed rotation and continuous erosion by chemical media accelerate lip wear, leading to a rapid decline in sealing performance; second, they are essentially ineffective against corrosive gases or vapors with small molecular size and high permeability. Therefore, the phenomenon of "water leakage and gas escape" occurs frequently, where liquid climbs up the shaft and gas escapes outwards, with the leaked medium crystallizing on the flange seat and surrounding equipment. This not only corrodes components and shortens equipment lifespan but also poses safety hazards and incurs high maintenance costs.

[0004] Based on the above, this application proposes a water pump sealing structure for etching equipment, which can effectively solve the above problems. Utility Model Content

[0005] To address the problem that existing single-frame oil seals are insufficient to prevent both liquid upflow and gas leakage during etching, thus leading to crystallization corrosion of the equipment, this application proposes a water pump sealing structure for etching equipment.

[0006] A water pump sealing structure for an etching apparatus, used to seal a motor shaft passing through a flange seat, comprising: A fixing sleeve is fixedly connected to the flange seat and sleeved on the motor shaft; A primary sealing kit is fitted onto the motor shaft and close to the side of the water pump and located at the end of the fixed sleeve for primary sealing of the motor shaft. A secondary sealing assembly is embedded inside the fixed sleeve and radially engages with the motor shaft to form a secondary seal on the motor shaft; and The primary sealing assembly and the secondary sealing assembly are arranged sequentially along the motor shaft from the side closest to the water pump outwards.

[0007] This application employs complementary components to address different types of leaks in a tiered manner. The primary sealing kit blocks most of the liquid at the source, while the secondary sealing kit throttles and depressurizes gases and droplets, and ultimately seals off any remaining trace amounts of media. This synergistic effect helps to simultaneously address both liquid upwelling and gas leakage, improving the overall reliability and durability of the seal.

[0008] In one embodiment, the primary sealing kit includes a water-blocking block and a set screw. The water-blocking block is fitted onto the motor shaft and has a threaded hole. The set screw passes through the threaded hole to lock the water-blocking block onto the motor shaft. This design actively intervenes at the source of leakage, using the centrifugal force of high-speed rotation to throw away most of the liquid attempting to rise. This not only prevents large-scale leakage but also creates a gentler working environment for subsequent seals, protecting them from the scouring and erosion of large amounts of liquid, thus helping to reduce wear and extend the service life of the overall sealing system.

[0009] In one embodiment, a blade extends radially from the upper surface of the water-blocking block, the diameter of which is larger than the outer diameter of the fixing sleeve. This blade primarily serves a secondary protective function when the primary sealing assembly rotates: firstly, it uses centrifugal force to fling away any trace amounts of liquid that may have infiltrated below the inlet of the fixing sleeve; secondly, the dynamic airflow barrier formed by its high-speed rotation effectively disrupts and hinders the upward path of corrosive gases.

[0010] In one embodiment, the secondary sealing assembly includes a primary seal and a secondary seal. The primary seal includes a water-retaining sleeve disposed within the fixed sleeve near the water pump. The inner wall of the water-retaining sleeve has multiple annular grooves, forming a radial clearance fit with the outer surface of the motor shaft. The secondary seal is a skeleton oil seal disposed on the side of the primary seal away from the water pump. This structure constitutes a non-contact labyrinth seal, specifically designed to handle gaseous or mist-like media that are difficult to handle with traditional skeleton oil seals. As the medium passes through the alternating annular gaps, it repeatedly undergoes throttling and pressure reduction, as well as expansion and energy dissipation, significantly weakening its kinetic and pressure energy, thereby reducing the tendency to leak outwards.

[0011] In one embodiment, the secondary seal includes a sealing lip that elastically abuts against the outer surface of the motor shaft, with the lip facing the side of the water pump. The secondary seal also includes an annular locking element fitted around the outer periphery of the sealing lip. The skeleton oil seal, as the final contact-type sealing barrier, is primarily used to intercept trace amounts of media that may penetrate the first two non-contact seals. Its inward-facing lip design allows any residual pressure to enhance its adhesion to the motor shaft, creating a pressure-self-tightening effect. The annular locking element provides a stable preload to the sealing lip to compensate for elastic decay after long-term use, ensuring the continued effectiveness of the final sealing barrier.

[0012] In one embodiment, the annular grooves are spaced apart along the axial direction of the motor shaft, and an annular platform is formed between adjacent annular grooves. The alternating structure of the annular platform and the annular groove is configured to achieve multi-stage throttling and energy dissipation for fluid and etching gas.

[0013] In one embodiment, the radial depth of the annular groove can be set between 0.1mm and 0.5mm. This preferred size range ensures, on the one hand, that there is sufficient clearance between the annular groove and the motor shaft to avoid contact and wear during equipment vibration, thus guaranteeing the reliability of the non-contact seal; on the other hand, the relatively small clearance can create effective fluid resistance and throttling effect, thereby balancing sealing performance and long-term operational durability.

[0014] In one embodiment, a static seal is provided on the mating surface between the fixed sleeve and the flange seat. This static seal fills the static mating surface between the fixed sleeve and the flange seat, preventing fluid or gas leakage from the mating surface and ensuring the integrity of the outer boundary of the entire sealing structure.

[0015] In one embodiment, the inner wall of the fixed sleeve is provided with an annular step, and the primary and secondary seals are respectively embedded in the corresponding annular step. The end face of the secondary seal away from the pump is flush with the end face of the fixed sleeve away from the pump. The annular step on the inner wall provides an accurate axial positioning reference and solid radial support for each seal, preventing displacement or tilting of the assembly during operation, ensuring the stability and consistency of the sealing gaps at each stage, and also simplifying the assembly process.

[0016] This application provides a water pump sealing structure for an etching device, which achieves the following technical effects: 1. Through a three-stage progressive protection design consisting of a primary sealing kit, a water-blocking bushing, and a skeleton oil seal, the system achieves active liquid ejection, pressure reduction and throttling of gas, and final sealing of minor leaks, solving the technical problem that traditional solutions cannot simultaneously prevent "water leakage" and "gas leakage".

[0017] 2. By setting an annular step inside the fixed sleeve to axially position each secondary seal and using static seals to ensure sealing of the mating surface with the flange seat, assembly is simplified, installation accuracy is guaranteed, and the integrity and operational stability of the entire sealing structure are ensured.

[0018] 3. By effectively preventing the leakage of corrosive media, crystallization and corrosion of the flange seat, seat plate and surrounding motor are avoided, extending the service life of the water pump and related equipment and reducing maintenance and replacement costs. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view of the water pump sealing structure of an etching device provided in this application.

[0020] Figure 2 for Figure 1 Enlarged diagram of point A in the middle.

[0021] Figure 3 The front view and top view of the fixing sleeve in the water pump sealing structure of an etching device provided in this application.

[0022] Figure 4 The front view and top view of the primary seal in the water pump sealing structure of an etching equipment provided in this application.

[0023] Figure 5 The front view and top view of the primary sealing kit in the water pump sealing structure of an etching device provided in this application.

[0024] Explanation of reference numerals in the attached figures: 1. Flange seat; 2. Motor shaft; 3. Fixing sleeve; 31. Annular step; 4. Primary sealing kit; 41. Water baffle; 42. Set screw; 411. Blade; 5. Secondary sealing kit; 51. Primary seal; 511. Annular groove; 512. Annular platform; 52. Secondary seal; 521. Sealing lip; 522. Annular locking element; 6. Static seal. Detailed Implementation

[0025] This application discloses a water pump sealing structure for an etching device, which is described below in conjunction with the appendix. Figure 1-5 This application will be described in further detail.

[0026] This application discloses a water pump sealing structure for etching equipment, used to seal a motor shaft 2 passing through a flange seat 1. It includes a fixed sleeve 3, a primary sealing assembly 4, and a secondary sealing assembly 5. The fixed sleeve 3 is connected to the flange seat 1. Both the primary sealing assembly 4 and the secondary sealing assembly 5 mate with the motor shaft 2. The secondary sealing assembly 5 includes a first-stage seal 51 and a second-stage seal 52. Along the motor shaft 2 from the inside to the outside of the pump, the primary sealing assembly 4, the first-stage seal 51, and the second-stage seal 52 are arranged sequentially. This multi-stage sealing effectively prevents liquid from flowing upwards and gas from escaping, reducing crystallization at the flange seat 1 and the seat plate.

[0027] In this embodiment, the fixing sleeve 3 is the supporting component of the entire sealing structure. It is connected to the flange seat 1 and provides an installation base for other components. The fixing sleeve 3 can be made of a metal material with good strength and corrosion resistance, such as stainless steel or aluminum alloy. In this embodiment, stainless steel is preferred. The fixing sleeve 3 can be connected to the flange seat 1 by welding or bolting. In this embodiment, bolting is preferred.

[0028] In this embodiment, the primary sealing assembly 4 is located on the side closest to the etching solution inside the pump. This assembly is, in this embodiment, an annular water-blocking block 41, made of polyetheretherketone (PEEK), which has excellent chemical resistance and a low coefficient of friction. The inner diameter of the water-blocking block 41 is tightly fitted with the outer diameter of the motor shaft 2, and is tightened by at least one radially arranged set screw 42 on its sidewall, thereby rotating synchronously with the motor shaft 2.

[0029] Specifically, on the end face of the baffle block 41 facing the fixed sleeve 3 away from the pump, a radially arranged annular blade 411 is provided. The radial outer diameter of the annular blade 411 is designed to be slightly larger than the outer diameter of the fixed sleeve 3, thus forming a "protective umbrella" structure below the inlet end of the fixed sleeve 3. When the body of the baffle block 41 rotates, it first throws away most of the upward-rushing liquid through centrifugal force. The radially extending blade 411 provides crucial secondary protection. For trace amounts of liquid or gas that successfully cross the lower edge of the baffle block 41 and enter below the inlet of the fixed sleeve 3, the high-speed rotating blade 411 will, on the one hand, capture them again through stronger centrifugal force and throw them outward. On the other hand, a turbulent air pressure zone is generated between the baffle block 41 and the fixed sleeve 3, forming a dynamic airflow barrier, which significantly increases the resistance to the upward penetration of gas molecules. Thus, in conjunction with the primary seal 51, it more effectively suppresses the "gas leakage" phenomenon.

[0030] In this embodiment, the secondary sealing kit 5 includes a primary seal 51 and a secondary seal 52, both of which are embedded inside the fixed sleeve 3 and radially cooperate with the motor shaft 2 to form a seal.

[0031] Specifically, along the motor shaft 2 from the inside of the pump to the outside, adjacent to the primary sealing kit 4, is the first-stage seal 51. The first-stage seal 51 includes a water-retaining bushing, which is made of wear-resistant and corrosion-resistant materials, such as ceramics or polytetrafluoroethylene (PTFE). In this embodiment, PTFE is preferred. Multiple rectangular annular grooves 511 are uniformly machined axially on the inner wall of the water-retaining bushing. A section of unmachined annular platform 512 is naturally formed between two adjacent annular grooves 511. The staggered arrangement of the annular grooves 511 and the annular platform 512 creates an alternating "wide-narrow-wide-narrow" gap structure between the inner wall of the water-retaining bushing and the outer surface of the motor shaft 2. When acidic gases and fluids generated during the etching process attempt to pass through this gap, they enter the annular groove region from the annular platform 512 region, i.e., from a narrow space to a relatively wide space. At this point, the upward pressure and velocity of the acidic gases and fluids decrease. Then, when they enter the next annular platform 512 region from the annular groove region, they are compressed and throttled again. After passing through these three-stage throttling-expansion chambers, the gas's energy is dissipated, and its flow rate slows down. Most of the acidic gas and fluid are effectively blocked here, making further upward leakage difficult. In this embodiment, the number of annular grooves 511 is preferably two.

[0032] Specifically, the radial depth of the annular groove 511 is set to be between 0.1mm and 0.5mm, and preferably 0.3mm in this embodiment. This size can ensure that while achieving throttling and energy dissipation, it will not cause excessive obstruction to the rotation of the motor shaft 2.

[0033] Specifically, the secondary seal 52 is located on the side of the primary seal 51 furthest from the pump, forming the final line of defense in this sealing structure. The secondary seal 52 is a standard fluororubber skeleton oil seal, including a sealing lip 521 and an annular locking element 522. The sealing lip 521 is positioned facing towards the pump, i.e., towards the water-retaining shaft sleeve. Due to the cross-sectional structure of the sealing lip 521, its opening faces the high-pressure side. When the residual medium pressure from inside the pump acts on the inner side of the sealing lip 521, this pressure is converted into a radial force, pushing the sealing lip 521 to fit more tightly against the surface of the motor shaft 2. Therefore, the greater the inner pressure on the sealing lip 521, the stronger its clamping force, forming a pressure-reinforced sealing effect, which helps maintain reliable sealing even in the presence of pressure fluctuations. The annular locking element 522 is fitted around the outer periphery of the sealing lip 521, preferably a stainless steel spring ring, to apply a persistent and stable radial preload to the sealing lip 521, ensuring that even if the material properties deteriorate after long-term operation, the sealing lip 521 can still maintain reliable contact and sealing with the surface of the motor shaft 2.

[0034] In this embodiment, to achieve stable installation of the aforementioned components, the inner hole of the fixing sleeve 3 is machined into a stepped hole structure, with the inner hole diameter decreasing sequentially from the inside of the pump to the outside, forming two annular steps 31. The water-retaining bushing is press-fitted into a larger stepped hole, with its end face axially positioned by the first annular step 31; the skeleton oil seal is press-fitted into a smaller stepped hole, with its end face axially positioned by the second annular step 31, and its end face away from the pump is approximately flush with the end face of the fixing sleeve 3 away from the pump. This stepped installation structure ensures precise axial positioning and stable support for each component, preventing movement during operation, and also makes assembly, disassembly, and maintenance very convenient.

[0035] In this embodiment, a static sealing element 6 is also provided on the mating surface of the fixed sleeve 3 and the flange seat 1. In this embodiment, the static sealing element 6 is preferably an annular graphite gasket. The graphite gasket has good anti-corrosion and sealing performance, and can fill the gap between the fixed sleeve 3 and the flange seat 1 to achieve static sealing between the fixed sleeve 3 and the flange seat 1, preventing fluid and acid gas from leaking from the mating surface of the two.

[0036] The working principle of the water pump sealing structure of the etching equipment provided in this application embodiment is as follows: This structure is based on a three-stage progressive synergistic sealing concept, with complementary protective barriers sequentially set up along the path where the medium may leak: First, the innermost primary sealing assembly 4 rotates at high speed with the motor shaft 2. Through centrifugal force, it actively throws most of the liquid etchant attempting to rise axially towards the radially outward and away from the sealing area. The water-blocking block 41 in the primary sealing assembly 4 throws away most of the liquid through centrifugal force, while the blades 411 on its upper surface provide crucial secondary protection. They not only throw away any remaining trace amounts of liquid, but their high-speed rotation also creates a dynamic airflow barrier that effectively blocks the upward path of the gas. This stage aims to intercept the main liquid medium at its source and provide initial obstruction to both gas and liquid media, creating a more gentle working environment for the subsequent secondary sealing assembly 5.

[0037] After the first stage, a small amount of fluid and acidic gas may enter the first-stage seal 51. As the medium passes through the labyrinthine gap formed by the inner wall of the water-retaining sleeve and the motor shaft 2, it repeatedly undergoes a throttling-expansion process. Each throttling effectively dissipates its pressure and kinetic energy. This stage, in a non-contact manner, weakens the leakage kinetic energy of the gaseous or liquid medium, specifically suppressing the "gas leakage" phenomenon.

[0038] After the first two stages of attenuation, any remaining trace amounts of low-pressure media may reach the second-stage seal 52. Under the preload of the spring ring, the elastic sealing lip 521 of the skeleton oil seal forms a reliable contact seal with the surface of the motor shaft 2. Its inward-facing lip design utilizes the residual media pressure to create a pressure self-tightening effect, completely sealing off any minute leaks. This stage serves as the final line of defense, ensuring the ultimate reliability of the seal.

[0039] In summary, this structure organically combines the three functions of blocking liquids, consuming gas energy, and finally sealing through a combination of static and dynamic processes and a hierarchical treatment. The first level of protection creates favorable conditions for the next level, and the components at each level cooperate with each other to jointly construct a composite sealing defense line that can simultaneously cope with the leakage of liquid and gaseous corrosive media.

[0040] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A water pump sealing structure for an etching device, used to seal a motor shaft (2) passing through a flange seat (1), characterized in that, include, The fixing sleeve (3) is fixedly connected to the flange seat (1) and sleeved on the motor shaft (2); A primary sealing kit (4) is fitted onto the motor shaft (2) and close to the side of the water pump and located at the end of the fixing sleeve (3) for primary sealing of the motor shaft (2); A secondary sealing assembly (5) is embedded inside the fixed sleeve (3) and radially engages with the motor shaft (2) to form a secondary seal on the motor shaft (2); and The primary sealing kit (4) and the secondary sealing kit (5) are arranged sequentially from the side closest to the water pump along the motor shaft (2).

2. The water pump sealing structure of the etching equipment according to claim 1, characterized in that, The primary sealing kit (4) includes a water-blocking block (41) and a set screw (42). The water-blocking block (41) is sleeved on the motor shaft (2). The water-blocking block (41) has a screw hole. The set screw (42) passes through the screw hole to lock the water-blocking block (41) to the motor shaft (2).

3. The water pump sealing structure of the etching equipment according to claim 2, characterized in that, A blade (411) extends radially from the upper end face of the water-blocking block (41), and the diameter of the blade (411) is larger than the outer diameter of the fixing sleeve (3).

4. The water pump sealing structure of the etching equipment according to claim 1, characterized in that, The secondary sealing kit (5) includes a primary seal (51) and a secondary seal (52). The primary seal (51) includes a water-blocking bushing, which is located inside the fixed sleeve (3) on the side close to the water pump. The inner wall of the water-blocking bushing has multiple annular grooves (511) that form a radial clearance fit with the outer surface of the motor shaft (2). The secondary seal (52) is a skeleton oil seal, which is located on the side of the primary seal (51) away from the water pump.

5. The water pump sealing structure of an etching equipment according to claim 4, characterized in that, The secondary seal (52) includes a sealing lip (521) that elastically abuts against the outer surface of the motor shaft (2), with the opening of the sealing lip (521) facing the side of the water pump.

6. The water pump sealing structure of an etching equipment according to claim 5, characterized in that, The secondary seal (52) further includes an annular locking member (522), which is fitted around the outer periphery of the sealing lip (521).

7. The water pump sealing structure of an etching equipment according to claim 4, characterized in that, The annular grooves (511) are spaced apart along the axial direction of the motor shaft (2), and an annular platform (512) is formed between adjacent annular grooves (511). The alternating structure of the annular platform (512) and the annular grooves (511) is configured to achieve multi-stage throttling and energy dissipation for fluids and etching gases.

8. The water pump sealing structure of an etching equipment according to claim 4, characterized in that, The radial depth of the annular groove (511) is set to be between 0.1 mm and 0.5 mm.

9. The water pump sealing structure of an etching equipment according to claim 1, characterized in that, A static seal (6) is provided on the mating surface between the fixed sleeve (3) and the flange seat (1).

10. The water pump sealing structure of an etching equipment according to claim 4, characterized in that, The inner wall of the fixed sleeve (3) is provided with an annular step (31). The first-stage seal (51) and the second-stage seal (52) are respectively embedded in the corresponding annular step (31). The end face of the second-stage seal (52) away from the pump is flush with the end face of the fixed sleeve (3) away from the pump.

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