Underwater bearing sliding part deterioration detection system, lubricant oil replenishment type oil seal

Abstract

The present invention aims to improve the system for detecting deterioration of the sliding parts of underwater bearings and to provide a lubricating oil replenishment type oil seal equipped with a through hole that allows lubricating oil to be supplied to the oil seal lip from outside the oil seal. [Solution] The present invention provides a sliding part deterioration detection system for an underwater bearing, comprising an underwater bearing 20 which includes a bearing housing 24 that supports a rotating shaft underwater and a lubricating oil supply unit 30 connected to the bearing housing that supplies lubricating oil to the gap with the rotating shaft at a predetermined pressure. One end of a pipe is connected to the bearing housing, and the other end of the pipe has an opening on land which provides a sliding part deterioration detection pipe 40 capable of detecting deterioration of the rotating sliding part and oil seal 28 from the pressure state of the lubricating oil that has moved to the bearing housing, the state of water contamination that has entered the lubricating oil, and changes in the appearance of the lubricating oil. Two or more oil seals are arranged along the longitudinal direction of the rotating shaft, and a lubricating oil replenishment hole is provided in one of the oil seals for replenishing lubricating oil, and the system is arranged in the bearing housing.

Description

Technical Field

[0001] The present invention relates to a sliding part deterioration detection system for a submerged bearing that detects secular deterioration due to wear of the submerged bearing attached to a rotating device such as a screw pump, and to the structure of a new oil seal.

Background Art

[0002] FIG. 3 is a schematic diagram showing the overall configuration of a screw pump. The screw pump 1 includes a rotating shaft (also referred to as a runner) 2 in which an upper shaft, blades (also referred to as an impeller), and a submerged shaft are integrated, a mortar casing 7, an upper bearing 4, a submerged bearing 5, and drive means 6. The screw pump 1 is disposed in an inclined water passage connecting an upper water passage and a lower water passage. The screw pump 1 configured as such can rotate the impeller 3 of the rotating shaft (runner) 2 by the drive means 6 to pump up the water in the lower water passage and send it to the upper water passage. The screw pump 1 is used for pumping and lateral movement of rainwater, seawater, sewage, sediment, sludge, chemicals, food, etc.

[0003] When the operation time of the rotating device is prolonged, the upper bearing 4 and the submerged bearing 5 experience wear at the rotating sliding part. In particular, for the submerged bearing 5 that supports the rotating shaft 2 of large rotating equipment applied to sewage treatment plants, water purification plants, etc. underwater, when fine solids such as sand and mud mixed in sewage and water enter the rotating sliding part of the bearing, due to the file effect, the wear of the sliding part is promoted. Therefore, in order to prevent sewage and solids from entering the rotating sliding part, the part where the underwater bearing and the rotating shaft 2 slide is filled with grease, and a high-quality oil seal is made single or double so that the grease does not leak from the sliding part, and a high-performance seal configuration for separating the grease part and the underwater part has been studied and developed. A lubricating grease supply part is provided in the bearing box that supports the rotating shaft 2 underwater. By moving the lubricating grease in the lubricating grease supply part along the rotating sliding part, it reduces the wear and heat generation due to frictional heat of the rotating sliding part during rotation, and avoids problems such as seizure of the rotating sliding part. Also, it attempts to stop the water and fine sand that try to enter the oil seal with the lubricating grease inside the submerged bearing.

[0004] The applicant has provided a sliding part deterioration detection tube that forcibly discharges the lubricating oil supplied to the bearing housing from the bearing housing. The lubricating oil sealed by the oil seal inside the bearing housing is released to the atmosphere through a pipe connected to the bearing housing, making it possible to detect deterioration of the rotating sliding parts and oil seals from the state of the lubricating oil pressure and the state of contamination of the lubricating oil with water and solid matter (disclosed in Patent Document 1). The inventors have achieved a usable period of approximately 7.5 years for the above-mentioned detection system with maintenance, but they would like to extend that period further. To that end, the development of oil seal materials and other improvements are desired. Conventional oil seals are made of plastic materials such as nitrile rubber, and deterioration over time is unavoidable with long-term use. Furthermore, it is desired that improving the sealing performance of the oil seal will extend the lubrication of the rotating sliding parts and thus increase the operating time of the screw pump. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 5869127 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The problem that this invention aims to solve, in view of the problems of the prior art described above, is how to delay the wear reduction due to friction between the rotating shaft or sleeve and the oil seal. The invention aims to improve the sliding part deterioration detection system of an underwater bearing by enhancing the sealing performance of the oil seal of the underwater bearing, and to provide a lubricating oil replenishment type oil seal equipped with a through hole that allows lubricating oil to be supplied to the oil seal lip from outside the oil seal. [Means for solving the problem]

[0007] The present invention provides a sliding part deterioration detection system for an underwater bearing, comprising a bearing housing that supports a rotating shaft in water, and a lubricating oil supply unit connected to the bearing housing that supplies lubricating oil at a predetermined pressure into the gap with the rotating shaft, with one end of a pipe connected to the bearing housing and the other end opening of the pipe located on land to release the pressure of the lubricating oil that has moved to the bearing housing to the atmosphere, thereby enabling the detection of deterioration of the rotating sliding part and oil seal from the state of the lubricating oil pressure, the state of water contamination that has entered the lubricating oil, and changes in the appearance of the lubricating oil, in an underwater bearing sliding part deterioration detection pipe, as a first means for solving the above problems, The objective is to provide a sliding part deterioration detection system for an underwater bearing, characterized in that the oil seal is made of wear-resistant polyurethane, two or more oil seals are arranged in a row along the longitudinal direction of the rotating shaft, and one of the oil seals is provided with a lubricating oil replenishment hole for replenishing lubricating oil, and these are arranged in the bearing housing. According to the first method described above, when multiple oil seals are arranged side by side, lubricating oil becomes less likely to penetrate the oil seals that are far from the lubricating oil supply, resulting in wear due to friction. Therefore, by changing the material of the oil seals from the conventionally used NBR (nitrile rubber) to polyurethane, resistance to frictional heat and wear can be improved. Furthermore, by arranging two or more oil seals side by side, the sealing performance of the oil seals can also be improved. In addition, the lubricity of the oil seals can be improved.

[0008] As a second means for solving the above problems, the present invention provides a lubricating oil-replenishable oil seal to be attached to a rotating shaft, The objective is to provide a lubricating oil replenishment type oil seal characterized by having a lubricating oil replenishment hole that penetrates from the outer circumference of the outer ring toward the center and supplies lubricating oil between the rotating sliding part of the rotating shaft or to the inside of the oil seal. According to the second method described above, the lubricity of the oil seal can be improved. However, care must be taken with the amount of lubricating oil to be added, as overheating can occur between the rotating shaft and the rotating sliding part. Furthermore, replenishing the inside of the oil seal can form a lubricating oil barrier that prevents the intrusion of contaminated water and fine sand.

[0009] As a third means to solve the above problems, the present invention provides a lubrication oil replenishment type oil seal characterized in that, in the second means, a lubrication oil replenishment pipe is connected to the lubrication oil replenishment hole and can supply the lubrication oil from outside the bearing housing, and a bearing housing replenishment hole is provided inside the bearing housing at a location opposite to the lubrication oil replenishment hole, or a ring-shaped replenishment groove is provided on the inner circumferential surface of the bearing housing. According to the third method described above, lubricating oil can be supplied forcibly and periodically from the maintenance passage through the lubricating oil replenishment hole, and in the case of underwater bearings, the intrusion of contaminated water and sand from underwater can be prevented. [Effects of the Invention]

[0010] According to the present invention, the sealing performance of the oil seal can be improved, and lubricating oil can be supplied to the inside of the oil seal, which is far from the lubricating oil supply part of the rotating shaft (installed on the impeller side), thereby preventing the intrusion of contaminated water and fine sand from underwater and forming a lubricating oil reservoir. By supplying lubricating oil to the seal lip of the oil seal, wear of the seal lip, the shaft, or the shaft sleeve can be slowed down. [Brief explanation of the drawing]

[0011] [Figure 1] This is an explanatory diagram illustrating the schematic configuration of the sliding part deterioration detection system for underwater bearings according to the present invention. [Figure 2] This is a magnified view of a part of a lubricating oil seal that requires replenishment of lubricating oil. [Figure 3] This is a schematic diagram showing the overall configuration of a conventional screw pump. [Modes for carrying out the invention]

[0012] Embodiments of the underwater bearing sliding part deterioration detection system and lubricating oil replenishment type oil seal of the present invention will be described in detail below with reference to the drawings.

[0013] [System for detecting deterioration of sliding parts of underwater bearings 10] Figure 1 is an explanatory diagram illustrating the schematic configuration of the sliding part deterioration detection system for underwater bearings according to the present invention. Figure 2 is a partially enlarged view of a lubricating oil replenishment type oil seal. As shown in the figure, the sliding part deterioration detection system 10 of the present invention for an underwater bearing comprises a bearing housing 24 that supports a rotating shaft underwater, and a lubricating oil supply unit 30 connected to the bearing housing 24 that supplies lubricating oil at a predetermined pressure into the gap with the rotating shaft 2. One end of a pipe is connected to the bearing housing 24, and the other end of the pipe has an opening on land to release the pressure of the lubricating oil that has moved to the bearing housing 24 to the atmosphere, thereby enabling the detection of deterioration of the rotating sliding part and the oil seal 28 from the state of the lubricating oil pressure, the state of water contamination that has entered the lubricating oil, and changes in the appearance of the lubricating oil. In this underwater bearing sliding part deterioration detection system 10, the material of the oil seal 28 is wear-resistant polyurethane, and two or more oil seals 28 are arranged side by side in the bearing housing 24 along the longitudinal direction of the rotating shaft 2.

[0014] The submersible bearing 20 is installed in a sewer and supports the lower end of the rotating shaft 2 of the rotating equipment. The submersible bearing 20 of this embodiment can be applied to rotating equipment that has a rotating shaft 2, a bearing, and a sprocket, such as screw pumps, vertical pumps, flocculators, sand and debris screw conveyors, and sludge scrapers. The submersible bearing 20 mainly consists of a bearing housing 24, a bearing metal 26, and an oil seal 28. The bearing housing 24 is a case that cylindrically supports the lower shaft 22 of the rotating shaft 2. The bearing housing 24 is attached to the connection point between the sewer channel and the inclined channel. Inside the bearing housing 24, a bearing metal 26 is disposed that makes surface contact with the rotating shaft 2, which has a sleeve 25 that forms a sliding part. The bearing metal 26 is a cylindrical sliding bearing with an inner diameter slightly larger than the outer diameter of the sleeve 25. A groove 50 is formed on the inner surface of the bearing metal 26 that makes surface contact with the sleeve 25. This groove 50 configuration allows lubricating oil supplied from the lower end of the bearing housing 24 to spread evenly into the gap between the sleeve 25 and the bearing metal 26. In the case of a structure where no metal is mounted on the shaft, the shaft and the bearing metal become the sliding parts.

[0015] The oil seal 28 seals the gap on the outer circumference of the lower shaft 22, preventing water, sand, mud, and other solid matter from entering the bearing housing 24. The oil seal 28 of the present invention is made of polyurethane and is arranged in pairs or more along the longitudinal direction of the lower shaft 22 between the bearing metals 26 inside the cylindrical bearing housing 24 (Figures 1 and 2 show three oil seals (28a, 28b, 28c) arranged). Due to the sealing performance of the oil seal 28, lubricating oil is released to the outside of the bearing via the sliding part deterioration detection tube 40.

[0016] The oil seal 28 consists of a polyurethane outer ring 280, a seal lip portion 281 continuous with the outer ring 280, and a spring 283. The outer ring 280 is in contact with the inner surface of the bearing housing 24. The tip of the seal lip portion 281 is in close contact with the lower shaft 22 of the rotating shaft 2. The spring 283 maintains the force pressing the seal lip portion 281 against the lower shaft 22. When the three oil seals 28 shown in Figures 1 and 2 are installed, the two oil seals 28a and 28b on the closed surface side of the bearing housing 24 have their seal lip portions 281 positioned towards the closed cover 23, preventing leakage of lubricating oil from the original sliding part. The oil seal 28c on the outside of the bearing housing 24 has its seal lip portion 281 facing the opposite direction, outwards. Furthermore, the lubricating oil replenishment type oil seal 28c is provided with a lubricating oil replenishment hole 61 (for improved lubrication) that penetrates the outer ring 280 in the diametrical direction and reaches the inside of the oil seal 28c (see Figure 2(1)). A lubricating oil replenishment pipe 62, which will be described later, is connected to the lubricating oil replenishment hole 61. The lubricating oil replenished from the lubricating oil replenishment pipe 62 accumulates inside the oil seal 28c through the lubricating oil replenishment hole 61 and flows out to the outside of the bearing housing 24 (see Figure 2(1)a), thereby preventing the intrusion of contaminated water and fine sand from underwater.

[0017] The lubricating grease replenishment type oil seal 28c shown in Fig. 2(2) is provided with a lubricating grease replenishment hole 61A (forming a barrier for lubricating grease) that penetrates the outer ring 280 in the central direction of the oil seal ring shape and reaches the sleeve 25 on the back surface (see Fig. 2(2)). A lubricating grease replenishment pipe 62 described later is connected to the lubricating grease replenishment hole 61A. The lubricating grease replenished from the lubricating grease replenishment pipe 62 accumulates between the oil seal 28c and the sleeve 25 through the lubricating grease replenishment hole 61A, and flows out to the oil seal 28b sandwiched between the oil seals 28a and 28c (see b in Fig. 2(2)), thereby reducing the frictional heat of the rotating sliding part due to rotation and preventing the seizure of the oil seal 28b. At this time, care must be taken because excessive supply of lubricating grease will conversely generate heat. In addition, the lubricating grease replenished from the lubricating grease replenishment hole 61 into the inside of the oil seal 28c accumulates in the gap between the seal lip part 281 and the oil seal retainer 27 to form a lubricating grease reservoir, which serves as a barrier against sewage and fine sand that invade from the outside. Thereby, lubricating grease as a lubricant and lubricating grease as a barrier can be supplied to the ring-shaped oil seal 28c. Although it is assumed that two or more oil seals of this embodiment are installed, the lubricating resin replenishment type oil seal provided with a lubricating grease replenishment hole can be applied practically regardless of whether it is used alone or at multiple locations of the oil seal. Also, among the plurality of oil seals, the lubricating grease replenishment hole can be formed for any one depending on the usage conditions.

[0018] The lubricating grease supply unit 30 is composed of a grease supply pipe 32 connected to the closing lid 23 of the bearing housing 24 and a grease pump 34 attached to the grease supply pipe 32. The grease pump 34 is connected to a lubricating grease tank and is arranged on land. The grease supply pipe 32 is arranged so as to be routed from the grease pump 34 on land to the bearing housing 24 in water. The lubricating grease supply unit 30 supplies lubricating grease into the bearing housing 24 through the grease supply pipe 32. The lubricating grease supply unit 30 causes the grease pump 34 to supply lubricating grease (such as grease) with lower fluidity than machine oil into the bearing housing 24 at a predetermined pressure.

[0019] The sliding part deterioration detection pipe 40 is a pipe with one end connected to the upper end of the bearing box 24 and the other end connected to the return lubricating grease receiving box on land. Since the lubricating grease that has moved inside the bearing box 24 is sealed by the oil seal 28, it passes through the sliding part deterioration detection pipe 40 that is open to the atmosphere and is discharged to the outside. Since the waterproofness of the oil seal 28 is at a depth of 5 meters or more, if the waterproofness of the oil seal 28 is maintained, the lubricating grease that has moved inside the bearing box 24 is discharged from the sliding part deterioration detection pipe 40 to the return lubricating grease receiving box. However, when the oil seal 28 deteriorates, the internal pressure of the bearing box 24 cannot be maintained, and the lubricating grease cannot be discharged. Thereby, deterioration of the oil seal 28 can be predicted. Alternatively, by checking the components (color, moisture content, etc.) of the discharged lubricating grease, the degree of its deterioration can be determined.

[0020] The lubricating grease replenishment part 60 includes a lubricating grease replenishment pipe 62, a replenishment groove 63, and a bearing box replenishment hole 64. One end of the lubricating grease replenishment pipe 62 is connected to the bearing box replenishment hole 64, and the other end is arranged on the ground. The replenishment groove 63 is a groove formed in a ring shape on the inner peripheral surface facing the lubricating grease replenishment holes 61 and 61A inside the bearing box 24 (see Fig. 2), and is connected to the bearing box replenishment hole 64 that penetrates from the outer periphery to the center of the bearing box 24. A plurality of lubricating grease replenishment holes 61 and 61A are formed on the outer periphery of the oil seal 28c (for example, on the upper part and both side surfaces, etc.). Alternatively, the lubricating grease may be replenished using the bearing box replenishment hole 64 having a larger diameter than the lubricating grease replenishment holes 61 and 61A instead of the replenishment groove 63. When the lubricating grease replenishment part 60 having such a configuration replenishes the lubricating grease automatically or manually at predetermined intervals from the ground, the lubricating grease can be replenished from the lubricating grease replenishment holes 61 and 61A that open to the outer periphery of the oil seal 28c through the bearing box replenishment hole 64 and the ring-shaped replenishment groove 63 to the inside of the oil seal 28c and between the oil seal 28 and the sleeve 25. The lubricating grease replenishment holes 61 and 61A can be used separately depending on the purpose of use (in the case of the lubricating grease replenishment hole 61A, if the replenishment amount is too much, it will cause problems).

[0021] [Function] The operation of the sliding part deterioration detection system and lubricating oil replenishment type oil seal for the underwater bearing of the present invention, as configured above, will be explained below. When the rotating equipment is in operation, in the underwater bearing 20, the rotating shaft 2 equipped with a sleeve 25 is supported by surface contact with the bearing metal 26 inside the bearing housing 24 and rotates at a predetermined rotational speed. At this time, lubricating oil is supplied into the bearing housing 24 by the lubricating oil supply unit 30. The lubricating oil is supplied at a predetermined pressure by the lubrication pump 34. The lubricating oil introduced from the lower end of the bearing housing 24 moves along the groove 50 formed in the bearing metal 26 in the gap between the sleeve 25 and the bearing metal 26. The groove 50 is formed in the bearing metal 26 along the outer circumference of the lower shaft 22 and is formed from the closing lid 23 of the bearing housing 24 toward the connection port of the sliding part deterioration detection tube 40. Therefore, the lubricating oil supplied into the bearing housing 24 can move evenly through the gap between the sleeve 25 and the bearing metal 26. The lubricating oil that has moved to the oil seal 28 of the bearing housing 24 is sealed off by multiple oil seals 28 inside the bearing housing 24, and is therefore discharged to the outside through the sliding part deterioration detection tube 40. Note that the oil seal 28 is in contact with the lower shaft 22 while rotating, and some leakage of lubricating oil into the water occurs.

[0022] In this embodiment, the oil seals 28 are arranged in pairs (two or more) along the longitudinal direction of the lower shaft 22 to enhance sealing performance. The oil seal 28c on the impeller side is supplied with lubricating oil from the lubricating oil supply section 60 via the lubricating oil supply hole 61. The lubricating oil accumulated inside the oil seal 28c becomes a grease reservoir, and some of it flows into the water to prevent the intrusion of sand and contaminated water from the water. Additionally, lubricating oil is supplied from the lubricating oil supply section 60 via the lubricating oil supply hole 61A, and accumulates between the oil seal 28c and the sleeve 25 from the lubricating oil supply hole 61A. This then flows out to the oil seal 28b sandwiched between oil seals 28a and 28c, thereby enhancing the lubrication of the rotating sliding parts due to rotation and preventing the oil seal 28b from seizing. The lubricating oil supply hole 61 or 61A is used depending on the purpose of use.

[0023] When lubricating oil is discharged to the outside through the sliding part deterioration detection tube 40, only lubricating oil is discharged during the initial stages of operation. After a predetermined operating time, wear of the oil seal 28 progresses. At this point, the degree of deterioration of the oil seal 28 can be determined from the color of the lubricating oil and the water content mixed in with the lubricating oil. Furthermore, as the oil seal 28 wears down, lubricating oil leaks from the oil seal 28 into the submerged area, preventing lubricating oil from flowing into the sliding part deterioration detection tube 40. In this way, the deterioration of the oil seal 28 can be detected.

[0024] Preferred embodiments of the present invention have been described above. However, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the invention. Furthermore, the present invention is not limited to the combinations shown in the embodiments, but can be implemented using various combinations. [Explanation of Symbols]

[0025] 1 Screw pump 2 rotation axes 3 Impellers 4 Upper bearing 5 Underwater bearings 6. Driving means 7. Mortar casing 10. Underwater bearing sliding part deterioration detection system 20 Underwater bearings 22 Lower shaft 23 Occlusion lid 24 Bearing housing 25 sleeves 26 Bearing Metal 27 Oil seal retainer 28 Oil seals 28c Lubricant Refillable Oil Seal 280 Outer ring 281 Seal lip section 283 Spring 30 Lubricating oil supply section 32. Lubrication supply piping 34. Lubrication pump 40. Sliding part deterioration detection tube 50 grooves 60 Lubricating oil replenishment section 61 Lubricant oil replenishment hole (improves lubricity) 61A Lubricating oil replenishment hole (formation of a lubricating oil barrier) 62 Lubricating oil replenishment piping 63 Refill groove 64 Bearing housing replenishment hole

Claims

1. A sliding part deterioration detection system for an underwater bearing comprises a bearing housing that supports a rotating shaft underwater, and a lubricating oil supply unit connected to the bearing housing that supplies lubricating oil at a predetermined pressure into the gap between the bearing housing and the rotating shaft, wherein one end of a pipe is connected to the bearing housing, and the other end of the pipe has an opening on land to release the pressure of the lubricating oil that has moved to the bearing housing to the atmosphere, thereby enabling the detection of deterioration of the rotating sliding part and oil seal from the state of the lubricating oil pressure, the state of water contamination in the lubricating oil, and changes in the appearance of the lubricating oil, A sliding part deterioration detection system for an underwater bearing, characterized in that the oil seal material is made of wear-resistant polyurethane, two or more oil seals are arranged in a row along the longitudinal direction of the rotating shaft, and one of the oil seals is provided with a lubricating oil replenishment hole for replenishing lubricating oil, and the system is arranged in the bearing housing.

2. A lubricating oil seal that is attached to a rotating shaft, A lubricating oil seal characterized by having a lubricating oil replenishment hole that penetrates from the outer circumference of the outer ring toward the center and supplies lubricating oil between the rotating sliding part of the rotating shaft or to the inside of the oil seal.

3. A lubricating oil replenishment type oil seal as described in claim 2, A lubrication oil replenishment type oil seal characterized by a lubrication oil replenishment pipe connected to the lubrication oil replenishment hole and capable of supplying the lubrication oil from outside the bearing housing, and a bearing housing replenishment hole located inside the bearing housing opposite the lubrication oil replenishment hole, or a ring-shaped replenishment groove provided on the inner circumferential surface of the bearing housing.

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