types of stern tube lubrication system
A brief history of propeller shaft stern tube solutions â¢eawater is the oldest lubricant for propeller shaft stern tube systems. In this article, the authors present an attempt at researching the possibility of more extensive use of other stiff bush bearings, represented by bronze bush bearings. The stern tube is filled with a lubrication medium and provides room for needed piping for example oil lines, temperature sensors and the Supreme Ventus ® system. This wide range of temperature change has influence on properties of water lubricated bearings. The propeller shaft from the engine passes through the stern tube and is connected with the propeller. ⢠Comparison of. The stern tube bearing consists of sealing arrangement to prevent ingress of water and to avoid the lubricating oil to escape into the sea. The topic of this article is conducting of the measurements on water lubricated main shaft bearings. There are various types of stern tube bearings available, for the selection you have to take several factors into consideration. But some doubts are evoked by their large value of shape elasticity module which can lead to local stress concentration at the bush edges in the case of non-axiality of bush and shaft axes. In most cases, it is a correct method because of negligible viscosity changes, Nitrile-butadiene rubber (NBR) and another polymer with an excellent self-lubricating property are blended to develop a new kind of polymer used for water-lubricated stern bearings. Figure 8.15 Oil lubricated stern tube (Simplex type) The static lubrication system for vessels with moderate changes in draught, have header tanks placed 2â3 m above the maximum load waterline. This allows the tail shaft to rotate smoothly in the bearing area for uninterrupted propulsion. This indicates blending rubber with other polymers is an effective means to develop low-friction stern bearing materials. The new test rig, presented in this paper gives wide research possibilities and working conditions are very similar to those on a real ship. In this study, four sliding bearings approved for use in shipbuilding were experimentally tested. ⢠Conclusion. polymer bearing bush on the basis of experiment" TRYBOLOGIA 2007, The first experimental tests of water lubricated sliding bearing with internal broached bearing bush, Dymarski C. Litwin W. "The first experimental tests of water lubricated sliding bearing with internal broached In many instances of hydrodynamic lubrication (HL), direct contact between the asperities will still occur in spite of the presence of HL film. The most commonly used oils are of the SAE 30 or SAE 40 types. © 2008-2021 ResearchGate GmbH. We will lear⦠Nevertheless, in todayâs operating climate water lubricated stern tube solutions are emerging as the sensible way to go. impact of the bushing materials and geometry of the bearing interspace on the hydrodynamic properties of the bearing, The tests stands for water lubricated marine main haft bearings, Litwin W "The tests stands for water lubricated marine main haft bearings" NORDTRIB 2006, Helsingor Dania, Influence of surface roughness on work of water lubricated main shaft bearing with polymer bearing bush on the basis of experiment, Dymarski C. Litwin W. "Influence of surface roughness on work of water lubricated main shaft bearing with These bearings are particularly advantageous when used with journals of relatively small diameters working under heavy loads. The article contains the following parts: ⢠Introduction in which the genesis and the main idea of work are described. Nowadays thereâs a much wider choice when it comes to stopping the water coming in via the stern tube. The system with the circulation is safer. The article contains the following parts: ⢠Description of the test stand, the simulated working conditions, and tested bearingsâ specifications. One of the main problems connected with this the bearings of this kind is defining maximum hydrodynamic film capacity. Since typical ships can freely sail on all oceans, the sea-water temperature could change more than twenty degrees. Experimental research conducted in the past was carried out on a single bearing test rig [1, 2, 3]. Thus, the standard solutions include water-lubricated bearings with polymer bushings or sealed systems lubricated with oil. When properly designed, assembled, and operated, bearings can operate reliably for years. Water lubricated bearings are often installed on new and modernized ships. Oil-lubricated systems are the most common, but ship owners also use water-lubricated and grease-lubricated systems. Any seawater that has leaked through the damaged or worn water seals into oil system can be separated out in the settling tank. Based on the conducted research, it can be concluded that bronze bearings may constitute an interesting alternative to nonmetallic bearings. Sealing. Seals are installed at the aft and forward end of the stern tube. Sterntube seals have to perform two separate functions, one is to ensure that water does not enter the engine room, the second one to allow the propeller shaft to rotate as smoothly and freely as possible. As it was proven under simulated working conditions hydrodynamic lubrication does not take place in typical bearing with grooved bearing bush. And the difference is the most evident at speeds of 0.1 ~ 2.0m/s. Lubricant manufacturers produce a variety of different lubricants for stern tube bearings. The results of the experimental work include: graphs of friction coefficient, pressures in the water hydrodynamic film and shaft trajectory. DUAL-LINE SYSTEMS. Although they require a hardened journal surface, they offer a greater load-bearing capacity, durability, and lower movement resistance levels. However in the subject â matter literature there is no reference to application of bearings fitted with metal or ceramic bushes in shipbuilding. ⢠Comparison of hybrid bearing with two others bearings. So in the structure design of water-lubricated rubber bearings, selecting proper structural parameter will improve the tribological performance. They can be blended with all types of mineral lubrication oil and can be used with all types of stern tube seal materials. The system consists of two sets of oil pumps. In terms of stern tube lubrication and seals and bearings there In addition, salinity of sea water influences viscosity, as well. However, specific operating conditions, such as a low rotational speed of the shaft, may result in intensive wear and premature failure. The article contains the following parts: ⢠Introduction in which the genesis and the main idea of work are described. The system is recommended for 710 mm seal systems and larger. â¡ This manual describes basic operation of stern tube system based on the typical lubrication diagram. The right choice for the environment A single barrier oil lip seal can potentially leak. The stern tube is a hollow tube-like structure at the stern or rear part of the ship. Stern tube lubrication system consist of a drain tank which acts as a reservoir for the storage of oil. They all comply with the 2013 EPA VGP requirements as environmentally acceptable. The mixed lubrication model of marine stern tube bearing covers all regimes of lubrication from hydrodynamic to boundary lubrications, which includes following submodels: (a) Mixed lubrication model. The stern tube is fitted at the stern frame and internal framing of vesselâs hull at aft peak. Use on vessels has proven that when Thruster+ is used preventively, it reduces the wear and risk of water leakage. ⢠Description of the test stand, the simulated working conditions, and the bearing specifications. An automatic lubrication system can have several types of configurations like - dual line system, single line volumetric system, single-line progressive system or a single point system. Furthermore, test results revealed that reducing the rubber layer thickness and hardness will reduce the friction coefficients. All rights reserved. It can be press-fitted or installed with epoxy resin. A housing with series of seal rings clamped into position on the bush. ⢠Results of the conducted measurements. Better known as the âDNV GL oil lubrication criteriaâ, it is based on a quasi-empirical solution of ⦠The aim of the research was to investigate stiff metal bearings, as solutions offering theoretically greater load bearing capacity than comparable elastic bearings, capable of replacing typical polymer and rubber bearings in certain applications. A larger sketch of the after seal (Figure 8.18) shows how seals are built up from three basic assemblies namely the flange, intermediate, and cover rings and these parts can be used for either seal. The results of the experimental work include: graphs of friction coefficient, pressures in the water hydrodynamic film and shaft trajectory. Stern tube is located at the aft end of the ship and is that part which connects the engine inside of the ship to the propeller outside of the ship. Lubrication liquid characteristic has significant influence on bearing properties and working conditions. In reality, water has surprisingly unique properties. Whilst PANOLIN provides stern tube oil, gear oils, hydraulic fluids and greases for all lubrication requirements on all propulsion types, it is the conventional propeller shaft with a stern tube containing the propeller shaft bearings and propeller shaft seals that ⦠New test rig will be ready for first test in December. The calculation method for the minimum shaft-rotational speed at which hydrodynamic lubrication of the aft stern tube bearing is ensured was introduced in 2013. Drain tank is a double bottom tank located in the aft of the engine room. New test rig powered by 220 kW motor. The method is based on DNV GL Maritime Advisoryâs research and published on SNAME conference 2009 (performance of stern tube bearings under different lubrication and operating conditions). In principle, the sterntube aft seals can function without a lubrication system. Confirm correction operation of stern tube system in the shipâs diagram. The small differential pressure ensures that water is excluded. The sterntube is installed from aft and bolted to the stern frame boss. Sterntube bearings â Oil-lubricated white metal bearing usually consists of two bushes pressed into a stern-tube. Typical main shaft bearing with grooved bearing bush working in a semi fluid friction conditions and hydrodynamic bearing with cull bearing bush (without any grooves). The Simplex stern tube (Figure 8.15) has a forward seal with two rings and an after seal with three rings. Because of environmental regulations, lubrication with grease or mineral oil is prohibited. Itâs carrying tail shaft, bearing, lubrication system and sealing arrangements. Mechanical Face Seals. In calculations of oil lubricated bearings oil viscosity changes resulting from increasing temperature are usually taken into consideration. TYPES OF LUBRICATING (OIL) SYSTEMS . The workâs essential conclusion is that fluid film lubrication is possible also in hybrid bearings with grooves. In order to prevent the water ingress stern tube bearings are used inside the stern tube. However, the aft sealing functions better and has a longer life if it is fitted, like the forward sealing, with a lubrication system. Packing Type. ⢠Conclusion. Stern tube oil, cable grease and gear oil from Klüber Lubrication share a focus on uncompromising performance, cost optimisation and extremely high standards for ⦠Common Stern Tube Seal Types Labyrinth Seals. Itâs small narrow hole in the shipâs hull at the aft of ship. A critical part of the ship, the stern tube can be a soft area for the sea water to seep inside the ship. Real scale water lubricated bearings tests in brakedown conditions. Figure 6-29. the friction coefficients of PBN are lower than those of NBR under water-lubricated conditions. The topic of this article is conducting of the measurements on water lubricated main shaft bearings. Various types of water-lubricated sliding bearings have been tested at the Technical University of Gdansk, including stiff composite bearings, ceramic bearings, as well as elastic polymer ones. Heavy processes industries predominantly use dual-line lubrication systems as they are very reliable, simple to understand and easy to maintain. In water lubricated bearings the isothermal model is usually applied. This hole is located at the aft of the ship and is necessary for the propeller shaft to pass through and connect with the propeller to the ship's engine. The test results showed that the choice of the bearing type has a key effect on friction during low-speed operation. Its flexible support gives possibility of shaft misalignment for instance in case of asymmetric hydrodynamic pressure film in the bearing. Development of plastic materials has caused that novel sliding polymers appeared available on the market and being approved by classification institutions, possible to be applied in shipbuilding. A ship needs the propeller to drive it forward in water. Water-lubricated bearings have been used for many years in shipbuilding, hydropower, and other industries because of their advantages, including extensive serviceable life, low coefficient of friction, longevity of shaft sleeve, good abrasion resistance, low maintenance required, unit simplicity, no danger of pollution, and low price. Low and high level switches on the settling tank allow clear observation and monitoring of the functioning of the aft seals. Circoolmatic pumps oil from the forward seal through a sea-orfreshwater cooling system, providing maximum lubrication. ⢠Results of the conducted measurements. The article contains the following parts: ⢠Description of the test stand, the simulated working conditions, and tested bearingsâ specifications. As it was proven under simulated working conditions hydrodynamic lubrication does not take place in typical bearing with grooved bearing bush. Oil loss can occur if there is no counter pressure from the outboard water. ⢠Presentation and description of the conducted measurements. The propeller shaft is used for connecting the shipâs engine and the propeller. ThordonWater QualityPackage Asteadysupplyofseawaterwiththe significantabrasivesremovedisan importantelementinensuringlong, predictable,bearingwearlife.Withthis The stern tube is installed at the stern of the ship and carries the sliding bearings that are used to support the propeller shaft. ⢠Comparison of hydrodynamic bearing with the typical main shaft bearing with a grooved bearing bushing working in a semi fluid friction conditions. Seal Technol, 2010 (2010), p. 1. Wärtsilä is a global leader in complete lifecycle power solutions for the marine and energy markets. Real scale water lubrcated bearng tests under brakedown conditions - limited cooling, Experimental Investigation on Marine Main Shaft Bearings With Reduced Length to Diameter Ratio. resulting from increasing pressure and temperature in the lubrication film. The main purpose of the conducted research was to identify how different bearing types operate under conditions of no lubricant flow. One important factor is the intended lubrication medium. Norden Marine Bearing´s Monitoring & Water Quality Package SystemPhone +47 5656 5570 mail: ove@nordenmb.no; tl@nordenmaritim.no; It calculates the minimum oil film thickness and maximum pressure and can be used as supplement to the minimum rotational speed result. It is common knowledge that a hole in the ship's hull will allow water to flow inside the ship, causing it to sink. The workâs essential conclusion is that fluid film lubrication is possible also in hybrid bearings with grooves. There are five main makes available in Britain â Tides Marine, Volvo, PSS, ManeCraft/Deep Sea Seals and Vetus â offering what are known as âdriplessâ shaft seals, claimed to be completely waterproof for leisure craft. Marine Propeller Shaft Bearings under Low-Speed Conditions: Water vs. Oil Lubrication, Water-Lubricated Sintered Bronze Journal BearingsâTheoretical and Experimental Research, Assessment of possible application of water lubricated sintered brass slide bearing for marine propeller shaft, Water Lubricated Polymer Hydrodynamic Bearing With Full and Grooved Bearing Bushing, Water Lubricated Hybrid Propeller Shaft Bearings With Polymer Bearing Bush. hydrodynamic bearing with the typical main shaft bearing with a grooved bearing bushing working in a semi fluid friction conditions. S â¢ater lubrication was first challenged by oil systems in 1886 after W which oil lubrication became the standard in the 1940s, the only exception was naval vessels. Especially in the open system some importunities such as sand and even algaeâ s gather inside the stern tu be (pic.1. Water: An Extraordinary, Ordinary Lubrication Liquid. oil lubricated stern tube bearing system is applied. In principle, the sterntube aft seals can function without a lubrication system. Influence of Water Salinity, Pressure and Temp... Tribological Performance of a Polymer Blend of NBR Used for Stern Bearings, Conference: ASME/STLE 2007 International Joint Tribology Conference. There are two basic types of anti-pollution seal system, the Air th these sealing solutions may operate on mineral oil lubricated stern tubes whilst maintaining an oil free environment under normal operating conditions. One of them is strong influence of pressure and temperature on viscosity. ⢠Comparison of hybrid bearing with two others bearings. Stern Tube is like hollow tube at the aft of ship. Bio Based Versions. The aft sealing is connected by means of two oil lubrication lines to a settling tank. It was unequivocally determined that a properly designed hydrodynamic water-lubricated journal bearing may function under a hydrodynamic regime in the conditions of typical loads and speeds found in practical applications. The propeller, located outside the ship, needs to be connected to the engine inside the shipâs engine room. Itâs the part of rear end shaft of propeller shaft and connects propeller at sea side. However, the aft sealing functions better and has a longer life if it is fitted, like the forward sealing, with a lubrication system. The article deals with water lubricated hybrid marine propeller shaft bearing which was designed and built at the Faculty of Ocean Engineering and Ship Technology of the Gdansk (Poland) University of Technology. Due to very thin hydrodynamic film and significant bearing bush deformation, the EHL model should be used for calculations. And with stern tube leaks easily monitored, this could lead to sanctions by port authorities, significant costs to the vessel operators Oil may also be used as a coolant and may be pumped from the mainstern tube bearing sump into the cooling coil, then into the main head tank. By emphasising technological innovation and total efficiency, Wärtsilä maximises the environmental and economic performance of the vessels and power plants of its customers. However, there is a hole which is deliberately provided in the ship's hull: the stern tube. The article deals with water lubricated hybrid marine propeller shaft bearing which was designed and built at the Faculty of Ocean Engineering and Ship Technology of the Gdansk (Poland) University of Technology. Some of the tested bearings had significant static friction with intense slip-stick phenomena; they should not be used in applications requiring low-speed operation. Similarly, any oil that has escaped from the oil seals can be drained to the waste oil tanks. In the opinion of these authors it could be applicable to bearing ship propeller shafts. ⢠Description of the test stand, the simulated working conditions, and the bearing specifications. There are various kinds of seal systems used, such as lip type or mechanical type for oil lubricated stern tubes. Until Vickers produced the first bio-degradable oil in 2002, all of the lubricants for metal bearings were mineral oil-based as are most available today. The results showed that, Join ResearchGate to discover and stay up-to-date with the latest research from leading experts in, Access scientific knowledge from anywhere. Hence this work has been aimed at the testing of a bearing made of bronze-graphite sinter. New test rig powered by 220 kW motor will be ready in December. The basic function is to prevent oil leakage from and seawater penetration into the stern tube. Water lubrication offers a wide range of benefits and is set to be the future of stern tube solutions. ... Closed oil-lubrication stern tube system replaces merchant shipâs water-lubricated bearings. So PBN will change to Plasto-Elastohydrodynamic (PEH) Lubrication at lower speed to reduce the critical speed of bearing squeal. Nevertheless they have important merits such as low resistance to motion, long service life or stability of form. bearing bush" NORDTRIB 2006, Helsingor Dania. ⢠Presentation and description of the conducted measurements. Now that you are familiar with the lubricating system components, you are ready to study the different systems that circulate oil through the engine. Sterntube seals, propeller shaft seals. Stern Tube+ and Thruster+ can be blended with all kinds of mineral and synthetic lubrication oil and can be used together with all types of stern tube seal material. lubrication or the closed system where distilled water is used. The oil is circulated by a small oil pump. Typical main shaft bearing with grooved bearing bush working in a semi fluid friction conditions and hydrodynamic bearing with cull bearing bush (without any grooves). The main reasons are: unit simplicity, no danger of pollution and low price. With some 90 percent of the worldâs shipping fleet using oil as a propeller shaft lubricant, it might be hard to make the case that water lubrication is a better option. ⢠In this booklet, all of water or oil pressures related to stern tube system are based on the âPRESSURE ABOVE SHAFT CENTERLINEâ unless it is specified. Although dated, permanent oil lubrication without circulation is still used. Unfortunately that test rig has some disadvantages. Water-lubricated bearings have been applied to support ship screw shafts for over a hundered years. In this article, youâll learn what is a lubrication system and different parts of lubrication system with images and PDF.. Lubrication is essentially required in motor vehicle maintenance. - Splash-type lubrication system. The bearings used in shipbuilding, hydropower, and water pumps have undergone a metamorphosis in recent decades. Our products are also available in Bio degradable oil based versions with both saturated and unsaterated ester. In the work is presented a comparison of measurement results of resistance to motion , hydrodynamic pressure distributions in lubricating film as well as shaft axis trajectories of the bearing, with those made for a typical elastic polymer bearing. SBTS â for research work on single bearing, PSBTS â for test of propeller shaft uni. Figure 3: Simple Spring Driven Mechanical Face Seal Cross Section. The measurement results have showed high quality of the tested material. ). To supply lubrication oil between the moving parts is simply termed as lubrication. Sterntube lubricating oil systems. Mobil Stern Tube Lubricant is a high performance, high viscosity lubricant developed especially for the lubrication of Cedervall-type stern tube bearings used in ships and for certain bearings of ships' fin stabilizers. The tribological performance of the new Polymer Blend of NBR (PBN), with the comparison of a rubber common used for most stern bearings, was studied using a stern bearing test rig of SSB-100.