There is a rotating mechanical shaft seal mech seal located in the head. The arrangement and the specific orientation of the rings are dictated by the application and the severity of the environment. The labyrinth seal consists of one or more sharpedged ridges machined on the outside diameter of a rotating shaft or on the inside diameter of a sealing passage as shown in fig. The other piece, called the rotor, is attached to the shaft and rotates with the motion of the system. One piece, known as the stator, is affixed to the machine and remains stationary. An experimental study of the high speed interaction between a labyrinth seal and an abradable coating in a turboengine application c. Jul 05, 2016 labyrinth seals are intended to prevent fluid liquid or gas flowing from one region to another, while not sealing off the passage entirely. A description of the types of high speed rotary shaft seals in gas. In this video, you can learn about all types of seal used in centrifugal compressor. This force throws contaminants out of the seal once they make it into the labyrinth maze.
Labyrinth seals are widely used in turbo machines to reduce leakage flow. The gmn noncontact seal has become famous for its compact design. Mechanical seals are simply another means of controlling leakage of a process where other means are deemed to be less capable of performing the task adequately. The head of the seal will be bolted to the bottom of the pump intake. These include oil seals and heavyduty taconite labyrinth seals with an axial labyrinth. An example of such a seal is sometimes found within an axles bearing to help prevent the leakage of the oil lubricating the bearing a labyrinth seal may be composed of many grooves that press tightly inside another axle, or inside a hole, so that the fluid has to pass through a long and. The halotm seal is a novel seal type, originating from the hbs, as a. The fundamental principles were developed in research projects by felix wankel. Morrison annular seals are devices used in turbomachinery to avoid flow losses which reduce efficiency. As the seal faces wear down over time, they must be closed to compensate for lost face material.
Pdf optimization of labyrinth seal for screw compressor. Pdf incompressible flow in a labyrinth seal researchgate. A description of the types of high speed rotary shaft seals. The basic principle of a labyrinth seal is based on the geometric shape of the mazelike labyrinth. The dynamic stability of the machine is also improved by the seal. Calculation of rotor dynamic coefficients for labyrinth seals. The laminar, compressible and axisymmetric flow in a rectangular labyrinth seal is treated and the seal performance is obtained. Continuing their previous research and development on noncontacting shaft seals the authors now concentrate on collecting labyrinth seals for machine tool spindles. Seals types 2 hydraulic sealsrod seal and piston seal. Inboard of the dry gas seal is an inner labyrinth seal, which separates the process gas from the gas seal. However, mathematical optimization theory provides a reli able and. Bearings which call for a high oil throughput are provided with seals with two labyrinth systems type 20.
A labyrinth seal is a type of mechanical seal that provides a tortuous path to help prevent leakage. I have attached a copy of their analysis and results within this report. Engineering a better noncontact seal the use of noncontact seals is not new. With swirl brake installed, theory gives less negative cross. A labyrinth seal is a type of mechanical seal that provides a tortuous path to help prevent. Another form of labyrinth and clearance seals is a laminar sealing ring, which uses a series of flat metal washerlike rings of varying diameters to create a labyrinth seal. C geometry of three canted knives with a smooth land case 3. Incorporates a gas type seal that effectively seals around the shaft to protect against static and dynamic liquid leakage. Labyrinth type steam seal, also known as labyrinth steam seal, has the following commonly used structural forms. Labyrinth seals for gas turbine engine general electric company. First measurements of labyrinth seals on a recently installed test rig operated. Labyrinth seal fda seals american high performance seals. Labyrinth packing is sufficient to prevent steam leakage of steam or air in steam turbine. Examples of labyrinth seal configurations by courtesy of sulzer metco.
The labyrinth gland can withstand higher steam conditions than the carbon ring gland. Labyrinth seals are intended to prevent fluid liquid or gas flowing from one region to another, while not sealing off the passage entirely. The teeth of the seal are designed to provide a close clearance with the counterface, and on large rotating. The general construc tion of both arrangements is the same, the main difference being that figure. An example of such a seal is sometimes found within an axles bearing to help prevent the leakage of the oil lubricating the bearing. In jet engines they rotor fluid interactions in stepped labyrinth seal. In the absence of entry swirl, the dimensionless equations governing the steady laminar compressible axisymmetric c0 w w t flow in the labyrinth seal may be. A further major correction was derived by considering boundary layer theory of schiliting 19 in the kinetic energy carry over coefficient. The subject matter of the present invention is a method for producing a labyrinth seal 10, wherein a digital data set is provided, which data set comprises threedimensional shape data of the labyrinth seal 10, wherein the labyrinth seal 10 comprises a first sealing element 12 and a second sealing element 14, which are configured corresponding to each other in such a manner that a. Within this study we will first familiarize ourselves with the basic labyrinth seal theory and alternative noncontact seals. A free floating labyrinth ring seal is sized to fit within a cavity to seal against a rotatable shaft to control excessive leakage of gas between high and low pressure chambers such as in a turbo machine. Please see the comparison with standard contact seals in the table below.
A labyrinth seal is a seal which creates a complicated path for liquids to pass through, making it challenging for liquids to cross the barrier created by the seal because they have difficulty making their way all the way through the labyrinth. Nov 10, 2016 labyrinth packing is sufficient to prevent steam leakage of steam or air in steam turbine. These types of seals are used in a variety of settings, and can be used on objects which rotate and otherwise move. In details, the labyrinth seals working principle is as follows. Pdf mechanical growth of labyrinth seal researchgate. The labyrinth seal is a special type of seal, used in screw compressors and turbomachinery for sealing purpose. Geometry of a stepped labyrinth seal configuration case 1.
What is new is the introduction of specialized designs that have evolved rapidly over the past few years. A clean buffer gas introduced at the intermediate labyrinth at slightly higher than the primary vent pressure creates a differential pressure that helps to keep the process gas from migrating to the secondary seal faces and helps to sweep the leakage of the seal gas in the primary vent. Labyrinth seal are used as the noncontact type seals between rotor and stator or fluid machineries, such as, steam turbines, gas turbines, compressors and so on. Halotm seal and, for comparison, a three tooth labyrinth seal. Victrex peek is used for the labyrinth seal because it delivers exceptional reliability compared with other polymers and metals, whilst working in hot gases, ammonia and sourgas environments. Labyrinth seals for gas turbine engine general electric. The basic functions of these labyrinths are discussed and put into practice. Aircraft cabin air and engine oil an engineering view pdf speech. Labyrinthtype steam seal, also known as labyrinth steam seal, has the following commonly used structural forms. The labyrinth seal is a controlled leakage seal used to prevent highpressure gas leaking out of the case to the atmosphere and minimizes internal leakage. They consist of a stationary and a rotating ring and are made of engineering plastic or other high. For a more complete description of dry gas seal principles of operation, see shah 1988. Laminar seal rings a smalley laminar seal ring set is a metallic labyrinth seal consisting of multiple rings in a groove. If the shaft oring must move when this compensation takes place, it is pushed forward by the components of the seal and by stuffing box pressure.
The authors of these theoretical studies seek to modify the theory with empirical correction factors to make the calculation fit test data. This maze inside the seal has so many turns, because of the peak formations, that contaminants or liquids have trouble making it all the way through the sel to the bearing. Tech nology outstanding physical p properties make peek. Dry gas seal systems for centrifugal compressors page 3. To assist in the sealing effect, air from the compressor volute casing is led into a space within the gland.
Labyrinth seals are constructed in multiple pieces. Other standard seals are also available for snl housings, but the housing has to be modified for the seal to be effective. Low pressure steam is supplied to final seats of labyrinths. Abstract the analysis of a rectangular labyrinth seals having several configurations is carried out in this study. I believe i understand how a labyrinth seal in a turbine engine works when a the engine is running. May 18, 1993 a labyrinth seal for a gas turbine engine of the type having a high pressure compressor and high pressure turbine, an outer shaft interconnecting the high pressure compressor and turbine, a low pressure compressor and turbine, and an inner shaft interconnecting the low pressure compressor and turbine in which the shafts are concentric and are.
The basic principle of a labyrinth seal is based on the geometric shape of the labyrinth which causes some turns of the contaminant on its way. The analysis is based on the assumptions that adiabatic conditions exist and that the. It consists of a ring having a series of machined fins. These seals are more info not designed to seal pressure differentials or to seal against high fluid levels. One key factor in this protection is centrifugal force caused by the machine applications rotation. Skf installation instructions of hrs and hss seals from skf for wind turbine main shafts duration. May 14, 2017 seals types 2 hydraulic sealsrod seal and piston seal. Labyrinth type seals are common devices for contaminant exclusion, and when properly maintained, they can greatly influence the reliability of the components in which they are installed a comparison of various seal materials ref. For the purposes of this discussion, consider that a mechanical seal will outperform common types of packing. The geometrical configuration of the labyrinth seal selected and the coordinate system used in the analysis are shown in fig. The principle of operation of a labyrinth seal by courtesy of sulzer metco. Labyrinth seals are also found on pistons, which use them to store oil and seal against high pressure during compression and power strokes, as well as on other nonrotating shafts. Well fluid moving into the pump intake will be on the top of this shaft seal. Pdf a preliminary numerical study has been conducted to study the effect of rotational speed on centrifugal growth in a sixtooth straight.
Simple modifications to breathers and sight glasses can be beneficial, but shaft seals are just as important in this process. A key advantage of peek in this application is the ability to run with tighter tolerances without fear of. Outboard of the dry gas seal is a barrier seal, which separates the gas seal from the compressor shaft bearings fig. Labyrinth seals or glands are fitted to the shaft and casing to prevent the leakage of exhaust gas into the turbine end bearing, or to prevent oil being drawn into the compressor. These types of seals are used in a variety of settings, and can be used on objects which rotate and. Wo2017220075a1 labyrinth seal and method for producing a.
Rto avt symposium on design principles and methods for aircraft gas turbine engines. It is necessary to manufacture 14 fits to get a seal with only 3 labyrinth steps and very often the mounting space of custom made labyrinth seals is very large. Labyrinth seal pumps acds labyrinth seal design is reliable and provides trouble free centrifugal pump operation eliminating the need for a traditional mechanical seal. Engineering a better noncontact seal machine design. The two pieces interlock to effectively seal out the majority of contaminants while holding in the lubricant. To improve the efficiency of these fluid machineries, pressure of the working fluid and rotating speed of rotor tend to become high while the clearance of labyrinth seal. Labyrinth seals and clearance seals selection guide. Wyssmann sulzerescher wyss ltd zurich, switzerland the prediction of rotordynamic coefficients for gas seals is achieved with the aid of a twovolume bulk flow model based on turbulent rotationally symmetric 3d flow calculations including swirl. There are 16 series of standard imperial and metric laminar seal ring. Ptfe seals parker hannifin 8 prdifa technology division general information 1 when to use ptfe seals in the 1960s, the addition of fillers was found to improve a number of physical properties, particularly creep and wear rate. A description of the types of high speed rotary shaft. Apr 08, 2020 a labyrinth seal is a seal which creates a complicated path for liquids to pass through, making it challenging for liquids to cross the barrier created by the seal because they have difficulty making their way all the way through the labyrinth. Geometry of a labyrinth seal with a smooth land, case 2. Labyrinth seals use a noncontact seal design and are specifically designed to protect bearings from splashing water and other contaminants.
When choosing labyrinth seals and clearance seals, the operating speed and temperature must be considered. Intuitively, they do this by taking advantage of the resistance to fluid flow depending on not just the p. Labyrinth seal article about labyrinth seal by the free. This way if oil escapes the first labyrinth of the oil seal, it is contained by the pressure of air coming from the outer cavity on the other side of the seal. In these applications, it is the long and difficult path and the formation of controlled fluid vortices plus some limited contactsealing action that creates the seal. A theoretical model for the design of a labyrinth seal gland. Also known as labyrinth steam seal, has the following commonly used structural forms. Labyrinth seal aotating seals, contactiess seals, gas path. If the seal is configured with a dynamic oring of this type the seal is called a pusher type. Actually air, which is provided at a higher pressure than oil, will enter the inner oil cavity and mix with oil to form a mist. Any oil that makes it past the first part of the seal is thrown outwards due to the centrifugal force, forms vortices and therefore cannot pass the second part.
These seals generally do not perform well at low operating speeds. The fins form a number of fine annular restrictions. Radial clearance labyrinth seal figures 1 and 2 show two arrangements of labyrinth seals in which the close running clearance is in a radial direction. A labyrinth seal for a gas turbine engine of the type having a high pressure compressor and high pressure turbine, an outer shaft interconnecting the high pressure compressor and turbine, a low pressure compressor and turbine, and an inner shaft interconnecting the low pressure compressor and turbine in which the shafts are concentric and are separated by the seal. Shorter deliveries are therefore possible in view of the simpler stocks 2.
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