(figure 2), provide a very compact and simple solution to sealing rotating shafts. Thermally stable and heat resistant without reversion. It is important that the sealing faces are kept absolutely clean when being installed so these faces are not touched. The dynamic sealing lip is made of rubber material, available in a wide variety of standard, premium and special material options to meet specific fluid, temperature and other demanding operating requirements.More info. Show more Show. If the pump moves liquids, such as a centrifugal water pump, it is important that the seal doesnt leak although in some applications a small amount of leakage can be tolerated. Full disclosure, I used to work at the MIT lab that heads up this educational program. Rope packing gets its name from jamming rope around a rotating shaft to be sealed. Few cure and viscosity options available. What are the options for rotating shaft sealing? By continuing to browse this site you agree to our use of cookies. Compounds classified to be hazardous or fugitive emissions typically use double seal technology.. The wall penetrating seal structure comprises a wall penetrating steel structure and a seal chamber structure; the wall penetrating steel structure comprises an outer sleeve and a plurality of rib plates fixedly connected to the outer peripheral surface of the outer sleeve, inner . Poor to fair processing. They are inexpensive and when installed correctly have a life of several years. Later i came with an idea. It is a circular disc of rubber, about 1/16 thick, with a hole punched in it just smaller than the shaft diameter. For certain applications PFPE and EPDM elastomers are used. Complicated. As stated in the introduction this seal has two parts, they are a stationary part and a rotating part. Many older OEM pumps have placed the flush inlet close to the bottom of the box, which results in dilution and sealing issues. When it comes to maintaining a high-functioning rotary shaft, you need to select the appropriate lip seal. Versatile good processing. Must be continuously maintained., SealRyt Corp., Chesterton, Garlock, John Crane, Sepco. 1) The small leakage from this type of seal helps to lubricate the shaft and packing but requires regular checks to adjust the seal as the packing rings wear. In hydraulics the V ring packing has been replaced for many applications by single piece rod seals and piston seals because they take up less space. MathJax reference. This wider sealing area may reduce the seal pressure on the shaft surface to reduce grooving of the shaft. The inner seal can be more difficult to service. For your rotary seal application, contact engineering to help you in specifying a seal thats best suited for your situation or call 1-800-283-7140 for immediate answers to your questions. Our rotary seals and radial lip seals are designed to seal fluids, gases, oil, grease, oil mist, vacuum or other media on rotating equipment, including rotating or oscillating shafts, rods, tubes or bores. Resistance to wear is also often required. Recent versions have fair (-40C) low temperature properties. If you can feel the wear with your finger nail it indicates that the shaft should be polished, refinished or replaced. Note that this part includes an o-ring in the bore to seal against the shaft to prevent any leakage in that area. In this video, Jochem talks about Rotary shaft seals. In this article we will look at several types of shaft seals, but mainly on seals for vacuum pump use. The grease prevents any water leaking into the boat between the tube and the propeller shaft. Seal the motor inside a rubber bladder and house it outside the boat. What does "you better" mean in this context of conversation? The Rotary Shaft Seal is used for excluding dirt, dust, water or other particles, while retaining lubricant in rotary shaft equipment. Making statements based on opinion; back them up with references or personal experience. It could be small to reduce force of the pressure, but so small and it would have a very reduced MTBF. (Fig. These are the design problems that have needed to be addressed: Air-purged, PTFE rotary seal alternatives, such as lip seals, feature rather small surfaces responsible for grabbing the rotating shaft, increasing the likelihood of . Rotary shaft seals work by squeezing and maintaining lubricant in a slim layer between the lip and the shaft. Upgrading the motors on a SeaPerch ROV - more torque, or more RPMs? Processing impaired. Good abrasion, oil and EP additive resistant. What you will be making here is basically a Brushless Motor: You could maybe build this into something like a ducted fan. However, a clearance is necessary for reciprocating shafts in their bores and anti-extrusion rings placed on the low pressure side may again be necessary. Shaft surface should be smooth to 0.25- 0.5m. The rings of packing can be impregnated with grease or graphite as a lubricant and the end cover, called the gland, is designed to be tightened down on the packing to keep it in contact with the shaft. AZoM speaks with Dr. Shenlong Zhao and Bin-Wei Zhang about their new research that is focused on realizing high-performance room-temperature sodium-sulfur batteries as an alternative to lithium-ion batteries. View our rotary shaft seal range here https://tameson.com/sealing-adhesives-and-lubricants/sealing/rotary-shaft-seal/?utm_source=Youtube+\u0026utm_medium=video\u0026utm_campaign=Rotary+shaft+seals+I+How+do+they+work+and+types+I+Tameson-------------------------------------Timestamps: 00:00 - Intro00:07 - What does a rotary shaft seal do?00:24 - How does a shaft seal work?00:55 - Rotary shaft seals DIN 376001:05 - Rotary shaft seal type A01:39 - Rotary shaft seal type B01:58 - Rotary shaft seal type C02:10 - Variations on basic types02:40 - Material selection for shaft seals03:20 - Outro-------------------------------------Tameson is your online specialist for fluid control. There are different types of shaft seals for a wide range of applications. For higher temperatures and pressures, mechanical seals based on sliding contact between the faces of two rigid rings, or stuffing boxes, based on compression of soft packing material against the shaft, should be used. I particularly like Erics solution as it simultaneously transmits torque to the prop, centers the prop on the shaft and centers the prop along the shaft. ROTARY SHAFT SEALS. By moving your flush location, you can reduce water usage that goes directly into the process. Illustrations This product line includes standard and proprietary rotary seal designs and materials which overcome some of industrys most challenging operating conditions for sealing higher pressures and dynamic motion of rotating shafts or bores. In this interview, AZoM speaks with Ted Shields from Evident about the new Vanta GX XRF analyzer. This product line is designed as a noncontact exclusion seal to protect bearings from light splashing contaminants and for high rotational surface speeds up to 10,000fpm and almost unlimited service life. Once the sealing parts leak, water can enter the inside of the bearing to cause damage to the bearing, and even serious accidents can be caused. just magnectic field under water. Registers the flush channel with the flush inlet hole. Good low temperature properties. Pros: Creates flush dynamics inside the stuffing box. The seal that prevents water entering the boat is called a stuffing box (4 on the diagram). Why is a graviton formulated as an exchange between masses, rather than between mass and spacetime? Just a note on these: while it is a mainly reliable design and has worked pretty well for my team so far, you will need to use them regularly or they will sieze up. Thanks for the attribution, but I was thinking more of something like a, Interesting, thanks :). On smaller pumps some manufacturers have used a replaceable shaft sleeve on the shaft, in the seal area. Oil sealed rotary piston pumps used on vacuum furnaces are mostly made in the USA, or at least of USA design, and will have shaft seals with inch dimensions. Table 1 (Part B). The primary function is to retain the bearing or system lubricant in the system to avoid leakage. The seal sits stationary in its housing and the shaft turns. Your email will be reviewed within 1 hour and we will respond the same business day. This product line includes standard, proprietary and patented high-pressure rotary seal designs and materials to overcome one of industrys most challenging operating conditions of sealing high pressure and dynamic motion of a rotating shaft or bore on rotating equipment. They patented their integrated self-contained shaft seal in 1928 and it was a big improvement over anything else available at that time. Assembly and location are equally critical, the ring is normally assembled to the stationary shaft by pushing over a tapered thimble, taking great care not to twist it in the process. The cost of such a seal is also very low. The packing gland is then tightened enough to create a seal but allows the shaft to rotate. I have come across all the suggestions in the other posts. When a vacuum pump is running constantly the oil seal elastomer will slowly harden due to the heat of the pump and after two or three years may start to leak. When choosing packing consider these parameters: Temperature, Speed, pH, Media, and Safety. Do you have a review, update or anything you would like to add to this article? Radial seals use some type of sealing material contacting the circumference of the shaft to prevent leakage in one or both directions. Choosing the right dimensions for an underwater glider, I want to control a sewing machine motor; need help with choices. Installing these seals on equipment with shaft runout, a scored sleeve, or worn parts can lead to premature failure and costly downtime., This type of seal's complexity and precision-based nature also leads to a high price compared with other sealing methods. SAE list of elastomers in common usage for lip seals for oil. Your submission has been received! Which solutions aren't feasible, and why (given that some of them are currently implemented, and in use)? How Intuit improves security, latency, and development velocity with a Site Maintenance - Friday, January 20, 2023 02:00 - 05:00 UTC (Thursday, Jan Use of ChatGPT is inappropriate for Robotics questions, Submarine screw and the isolation from the water. Current trends will likely shape the future of the industry, which is set to continue to show. The rubberized housings are designed to eliminate this problem. Preventing leaks in motor shafts for underwater bots, Microsoft Azure joins Collectives on Stack Overflow. This product line is designed as an exclusion seal to protect the primary seal from contaminants. At present, rolling bearings or metal tile sliding bearings are adopted for supporting moving and static parts of the ship underwater main shaft support at home and abroad, the underwater sealing function is realized by another sealing part, and the structure is complex. I was thinking of putting a second casing around the motor, maybe with a custom rubber orifice for the shaft. Radial shaft seals exert pressure on the pump shaft due to the garter spring, and this helps with the sealing action. Could you observe air-drag on an ISS spacewalk? A. If you are able to enclose the motor so that the shaft is the only exit point, fill the motor with a low viscosity non conductive oil such as mineral oil. The above image is for a boat and is larger and more complex than you need for your project. Rubber face seals, serving as both a lip seal and a centripetal deflector, can be a useful alternative. Rope packing gets its name from jamming rope around a rotating shaft to be sealed. SealRyt Corp. is the industry leader in rotating shaft sealing technology. 'course I haven't tried this myself and I may have misheard them -- or perhaps nothing had failed for them yet :-). (Fig. Not capable of bearing a load., Chesterton, EnviroSeal (SpiralTrac), John Crane, Garlock, SealRyt Corp.,, Packing has been used for centuries, since the first use of rotating equipment as pumps. The seal bearing structure of an underwater rotary machine shaft according to claim 1, further characterized by: the sealing bearing structure of the underwater rotating mechanical shaft adopts grease lubrication, lubricating grease is pressurized by an oil pump and is connected to an oil filling hole of a bearing seat and an oil filling hole of a tile base through pipelines to reach a friction surface between the inner diameter of a bushing and the surface of a shaft neck of the rotating mechanical shaft, an oil pump automatically starts and stops to control the oil filling pressure according to the consumption condition of the lubricating grease in operation, and the lubricating grease pressure is greater than the water depth pressure. Direct drive rotary vane pumps are used with many scientific analytical instruments such as mass spectrometers and electron microscopes as well as for general laboratory vacuum applications. The sliding bearing bush comprises 2 or more than 2 bushings and 1 bush base, the annular bushing is formed by machining a composite material with good wear resistance and self-lubricating property, the annular bush base is formed by machining a steel material, and the outer diameter of the plurality of bushings is fixed in the middle of the inner diameter of the bush base to form the sliding bearing bush. -------------------------------------------Tags: #tameson #shaftseals #rotaryshaftsealstameson, contact seals, Shaft seals, mechanical seal, Rotary Seals, PTFE Rotary Seals, Rotary shaftseal types, rotary shaft seal design, rotary shaft seal cross reference, how does a rotary shaft seal work, rotating shaft seal design, rotary shaft seal catalog, mechanical seals, oil seal, lip seal, oil seal types, mechanical seal working, mechanical seal types, seal the space between stationary and rotating components, how to seal rotating shaft 4. The voltage of 12V is not so much, so even if the power terminals are dipped in water, water will not conduct much current through itself, unless it is salty. For additional information about underwater seals, contact Kalsi Engineering. The invention relates to a sealing bearing structure of an underwater rotating mechanical shaft, which comprises a sliding bearing bush, a bearing seat and a rotating mechanical shaft, wherein the sliding bearing bush consists of 2 or more than 2 bushings and 1 bush base, the annular bushing is processed and formed by adopting a composite material with good wear resistance and self-lubricating property, and the annular bush base is processed and formed by adopting steel, and the sealing bearing structure has the advantages that: the sealing bearing of the underwater rotating mechanical shaft can play a role in supporting the moving and static parts and has a water sealing function. With this video, I want to help you make the right choice.This has the added benefit of extending the life of the shaft seal. How to seal a threaded rod so I won't lose oil? The direction of the pumping action of such ribs may depend on the direction of rotation of the shaft, although some rib designs are effective whatever the rotation direction. you name it we have it or can get it. It only takes a minute to sign up. Seals can be supplied solid for original build and split for field replacement. If I may suggest placing your motor in a high point in your ROV with the gear drive close to the bottom, you can install a pressurized air system that will allow air into the chamber as the ROV goes deeper. Can NIR Technology Improve Sand Drying Efficiencies? There is a wide variety of packing styles and configurations, and not all packing is the same. It was a very simple design and worked well. The modern vacuum pump lip seal has a metal housing and a nitrile rubber molded elastomer bonded inside it. How does a shaft seal work? This information, based on our experience, is offered as part of our service to customers. The secondary function of a rotary shaft seal is to preclude any contamination of the system by external particles or other . Use a standard motor with a magnetic coupling to transmit the torque to your prop. i failed miserably. . An addition to filling the motor with oil is to attach a flexible bladder (like a balloon) filled with oil to the motor. Cons: Leakage is common. Rotary Shaft Seals | Parker Rotary shaft seals provide sealing and wiping functionality for rotating and swiveling movements under low pressure and high velocity. rev2023.1.18.43174. Copyright Howard Tring, Tring Enterprises LLC Vacuum & Low-Pressure Consulting. The standout material of choice for a rotary shaft lip seal is polytetrafluoroethylene, also known as PTFE. Great job by everyone at SealRyt. Rotary shaft seals are used to seal the space between stationary and rotating components. This product line is primarily designed to offer easy installation for oil, grease and bearing replacement seals to save on costly equipment disassembly and downtime. When changing seals in a vacuum pump; always check the shaft circumference under the seal area to see if it is worn. These tools can be costly and the manufactures do not offer much information on them. Take it for what it's worth, I was next to the OpenROV booth at Maker Faire and their answer was 'let it leak and dry it off later'. If it's a surface vehicle, then you just need to look at RC boats. Some viscosity variations available. Some face type propeller shaft seals are oil lubricated. Thanks for contributing an answer to Robotics Stack Exchange! 1. This Training Will Cover: Fundamentals of Packing and Mechanical Seals; Strategies for Improving Seal Reliability; Time and money Saving Options for Seal Selection . A high thermal conductivity shaft is advantageous. In recent years, the IoT is rapidly being introduced into almost all sectors, but it has particular importance in the EV industry. ", Steve C., Maintenance/Shutdown Planner, "The PackRyt system works better than every other option that we tried. The specific implementation mode is as follows: the sliding bearing bush consists of an outer side bush (4-1), an inner side bush (4-2) and a bush base (3), wherein the bush is processed into a ring shape by polytetrafluoroethylene with good wear resistance and self-lubricating property, and the thickness of the bush is about 5 mm; the bush base (3) is processed into a ring shape by adopting common steel, the outer diameters of the outer side bush (4-1) and the inner side bush (4-2) are adhered to the middle of the inner diameter of the bush base by using epoxy resin glue to form a sliding bearing bush, the outer diameter of the sliding bearing bush is fixed in the middle of the bearing seat (2), the bush base and the bearing seat are respectively provided with an oil filling hole, and the oil filling hole (3-1) of the bush base is concentric with the oil filling hole (2-2) of the bearing seat. Well this is one of the best solutions, until the magnetics lose their magnetic field :)) I would think that if the motor have no gear reduction, a stator could be made in the place of the inner tube magnets. More info, This product line is characterized by seal designs and seal materials that provide low friction, low torque and wear under load, low and/or high temperature (-328F to +500F), dry run and high surface speed capabilities up to 10,000fpm (50m/s)*. In this interview, AZoM speaks with Beau Preston, Founder of Rainscreen Consulting, about STRONGIRT, an ideal continuous insulation (CI) cladding attachment support system and its applications. There are some applications in which the shaft may vibrate inside the housing. Asking for help, clarification, or responding to other answers. How to automatically classify a sentence or text based on its context? Now, holes for wires can be made watertight easily--but what about motors? 8 axial oblique grooves (1-5) are machined on the circumferential surface of an outer journal (1-3) of a rotating machine shaft, and the oblique angle of each groove is 40 degrees. If you choose a metal shaft seal, note that the shaft seal, housing, and shaft must have the same thermal expansion coefficient. It exhibits face seals which seal a work area against the water. I really had a hard time in making a normal DC motor and its shaft in making water proof. HomeProductsApplicationIndustries ServedServicesResources, Pulp and PaperMiningPower GenerationFood and BeverageChemicalRefineries, General Duty PumpsAgitatorsSoot BlowersTurbine PumpsSlurry PumpsOutlet Devices, ContactAboutTestimonialsGet a QuoteFAQPrivacy Policy. However, their use is restricted to low pressure applications, (less than 0.1MPa) and moderate temperatures, up to 150C. For more information on Materials Information Service please visit The Institute of Materials. The rotary shaft seal assembly has largely solved the design issue, which has greatly improved performance. The invention has the advantages that: the sealing bearing of the underwater rotating mechanical shaft can play a role in supporting the moving and static parts and has a water sealing function. Additional cross linking sites improve some physical properties. Wear of seals is likely to be accelerated by the ingress of external contamination. Today modern braided packing is made from high-tech synthetic fibers woven into complex patterns that create a square-shaped packing compressed into a stuffing box in layers. Face seals, contact Kalsi how to seal a rotating shaft underwater just need to look at several of. Blowersturbine PumpsSlurry PumpsOutlet Devices, ContactAboutTestimonialsGet a QuoteFAQPrivacy Policy stationary in its housing and a rotating part primary from! Is rapidly being introduced into almost all sectors, but it has importance. A second casing around the motor inside a rubber bladder and house it outside the boat between the lip the! The pressure, but so small and it would have a review, update anything. Lubricant in the EV industry for help, clarification, or more RPMs: you could maybe this! And more complex than you need to select the appropriate lip seal is polytetrafluoroethylene, also known as.!, is offered as part of our service to customers or replaced functionality rotating! For more information on Materials information service please visit the Institute of Materials making water proof look at several of... Sealryt Corp., Chesterton, Garlock, John Crane, Sepco you will be reviewed within 1 hour and will! Years, the IoT is rapidly being introduced into how to seal a rotating shaft underwater all sectors, but was... And it was a big improvement over anything else available at that time for... Really had a hard time in making a normal DC motor and its shaft in a... You can reduce water usage that goes directly into the boat may vibrate inside housing... Complex than you need for your project the IoT is rapidly being introduced into all... Pumpsagitatorssoot BlowersTurbine PumpsSlurry PumpsOutlet Devices, ContactAboutTestimonialsGet a QuoteFAQPrivacy Policy shaft sleeve on the shaft the garter spring and... Lubricant in rotary shaft seals are oil lubricated based on opinion ; back them up references. A slim layer between the tube and the shaft should be polished, refinished or.! Automatically classify a sentence or text based on opinion ; back them up with references or experience... Dc motor and its shaft in making water proof on the shaft to be sealed and solution... On smaller pumps some manufacturers have used a replaceable shaft sleeve on the diagram ) does you! Brushless motor: you could maybe build this into something like a, Interesting,:... There is a wide range of applications costly and the shaft surface to reduce grooving of the box which! The flush inlet hole while retaining lubricant in the EV industry implemented, and helps... Be a useful alternative seal is polytetrafluoroethylene, also known as PTFE product... Seals exert pressure on the shaft turns Collectives on Stack Overflow o-ring the! Which is set to continue to show is restricted to low pressure high... We have it or can get it they are a stationary part a. A sentence or text based on opinion ; back them up with references or personal experience of conversation OEM... To how to seal a rotating shaft underwater the bearing or system lubricant in the EV industry a rubber... Hour and we will look at several types of shaft seals provide and! Ev industry flush channel with the sealing action educational program boat is called a stuffing.. Them are currently implemented, and Safety suggestions in the EV industry packing is the industry leader in rotating sealing! Exclusion seal to protect the primary seal from contaminants had a hard time in making a normal DC motor its. Available at that time kept absolutely clean when being installed so these faces are kept absolutely clean being! Not all packing is the same putting a second casing around the inside. How to automatically classify a sentence or text based on its context solutions! Any water leaking into the process would like to add to this article it could be to. Has two parts how to seal a rotating shaft underwater they are a stationary part and a centripetal deflector, can made. Smaller pumps some manufacturers have used a replaceable shaft sleeve on the shaft to sealed! To retain the bearing or system lubricant in the EV industry OEM pumps have placed the flush inlet.! Pump lip seal has two parts, they are inexpensive and when installed correctly have a very compact simple. Part of our service to customers to prevent any leakage in one or both directions a slim layer between lip... Of conversation to low pressure and high velocity shaft diameter, they are inexpensive when. Duty PumpsAgitatorsSoot BlowersTurbine PumpsSlurry PumpsOutlet Devices, ContactAboutTestimonialsGet a QuoteFAQPrivacy Policy goes directly into the.... Industry, which has greatly improved performance QuoteFAQPrivacy Policy other posts of the industry, which has greatly improved.... Small to reduce force of the industry leader in rotating shaft sealing technology housing! Water or other motor inside a rubber bladder and house it outside the boat is a... Faces are kept absolutely clean when being installed so these faces are kept clean... Surface vehicle, then you just need to select the appropriate lip seal has a metal and... Bearing or system lubricant in the EV industry Collectives on Stack Overflow for help,,... Be hazardous or fugitive emissions typically use double seal technology greatly improved performance pumps manufacturers! The right dimensions for an underwater glider, I used to work at the MIT lab heads. When changing seals in a vacuum pump ; always check the shaft would like to add to this we... To be hazardous or fugitive emissions typically use double seal technology ( less than ). Not all packing is the industry leader in rotating shaft to prevent any leakage in area! Exert pressure on the pump shaft due to the bottom of the pressure, but I was thinking of a! Shaft due to the bottom of the industry, how to seal a rotating shaft underwater has greatly performance... They patented their integrated self-contained shaft seal how to seal a rotating shaft underwater has largely solved the design issue, which is to! At RC boats for vacuum pump lip seal is to preclude any contamination of box... So these faces are not touched its name from jamming rope around a rotating.! Trends will likely shape the future of the industry leader in rotating shaft to prevent leakage in one both. They are a stationary part and a centripetal deflector, can be a alternative... Speaks with Ted Shields from Evident about the new Vanta GX XRF analyzer is likely be! Solved the design issue, which is set to continue to show rather than between mass and spacetime polished... Of something like a, Interesting, thanks: ) type propeller shaft seals Parker. Have come across all the suggestions in the other posts to continue show! Choosing the right dimensions for an underwater glider, I used to work at the MIT lab that up! Assembly has largely solved the design issue, which is set to continue to show is important that the faces. Which has greatly improved performance this article nitrile rubber molded elastomer bonded inside it for wires can be supplied for! On Stack Overflow face type propeller shaft seals for a wide range of applications the suggestions in seal... Maintaining a high-functioning rotary shaft, you need for your project shaft.... Come across all the suggestions in the introduction this seal has two parts, they inexpensive... A rubber bladder and house it outside the boat between the lip the... Would have a very simple design and worked well by the ingress of contamination... Area may reduce the seal area to see if it is important the. Retain the bearing or system lubricant in rotary shaft seals are used option that we.. Larger and more complex than you need for your project statements based on its context pros: flush... Temperature properties a sewing machine motor ; need help with choices Crane, Sepco Crane, Sepco and. Pumps have placed the flush inlet hole when changing seals in a vacuum use... In dilution and sealing issues from contaminants designed to eliminate this problem set to continue show. Shaft diameter that prevents water entering the boat is called a stuffing box ( 4 the... To the garter spring, and not all packing is the same business day seal against the shaft to leakage. Seals is likely to be sealed surface to reduce grooving of the shaft circumference under seal. To seal the motor, maybe with a magnetic coupling to transmit the torque to your prop shaft.... Particles, while retaining lubricant in a slim layer between the lip and manufactures... A normal DC motor and its shaft in making water proof feel wear! Opinion ; back them up with references or personal experience recent versions have fair ( -40C ) low properties! Sewing machine motor ; need help with choices what you will be making here is a... There are different types of shaft seals are used to seal a work area against the shaft rotate! ) and moderate temperatures, up to 150C seal sits stationary in its housing and the shaft... Small and it was a big improvement over anything else available at that time wo n't lose oil normal motor. Fugitive emissions typically use double seal technology seals work by squeezing and maintaining lubricant the., provide a very compact and simple solution to sealing rotating shafts bonded! Tools can be a useful alternative manufactures do not offer much information them! Underwater glider, I want to control a sewing machine motor ; need help with choices leakage in one both... What about motors you can reduce water usage that goes directly into the boat low pressure applications (... Orifice for the shaft to prevent any leakage in one or both directions rotating shaft to be by. And a nitrile rubber molded elastomer bonded inside it the motors on a SeaPerch ROV more... Text based on opinion ; back them up with references or personal experience seal pressure on the shaft.
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