Our innovations in secondary seals are designed to eliminate the causes of oring hangup, the most common operational challenge in other compressor gas seal designs. For more details about flow field of dry gas seal, the numerical simulation is carried out based on the navierstokes equation, laminar model, and simplec method, with. Common dry gas seal failures are discussed below along with their causes and remedies. A clean and dry separation gas is continuously injected into the barrier seal to protect the migration of lube oil from the outboard bearing housing. Rotary shaft seals work by squeezing and maintaining lubricant in a slim layer between the lip and the shaft. Liquid ring vacuum pump working principle and pumping. The separation gas should be filtered to 5 microns solid particles and should be 99. A cobey gas seal panel is designed to supply seal buffer gas to the shaft seals of various rotating compressors, providing containment of these process gases.
Dry gas seals are noncontacting, dryrunning mechanical face seals that consist of a mating rotating ring and a primary stationary ring. John cranes comprehensive range of dry gas mechanical seals are designed to provide you with the correct seal solution suited for your specific application, to ensure optimal reliability, safety and performance. The present invention relates to a centrifugal compressor using a dry gas seal system for protecting seal means. We are committed to providing the latest technologies and designs in order to provide our turbo machinery customers within global energy industries with. The primary ring is radially restrained but can move in the axial direction. In these applications, it is the long and difficult path and the formation of controlled fluid vortices plus. Manual or customerspecified systems can be engineered for most gas seal types. Compressor was stopped and performed static test with low pressure nitrogen to confirm the nde seal health condition before change out as the last dry gas seal was changed one year back due to the same problem. The specific compression energy transmitted to the gas by the impeller is called head. This action ensures the gas vented from the secondary seal will be mostly nitrogen during normal operation, since nitrogen supplied between the. Recently, as interest in carbon sequestration has increased, john crane has received a growing number of inquiries regarding how to seal supercritical co 2.
Key considerations for dry gas seal performance flow control. The information found in dry gas seals handbook will help you make informed decisions regarding the application, operation, and maintenance of dry gas seals. Both proven liftoff patterns have high film stiffness and damping capabilities that maintain the gas film under slow roll conditions as well as high speeds up to 250 ms 49,212 fpm. There are two basic types of gas seal systems differential pressure d p control. Dry gas seal arrangement typical dry gas seal seal face of dry gas theory of noncontact lift off of stationary ring achieved by increased pressure at the taper. Dry gas seal systems the use of dry gas seals requires a system designed to supply sealing gas to the seal as a sealing and working fluid for the running gap. The primary focus on mechanical seal animation and graphic helps in very clearly understanding mechanical seal working principle operating principle.
A dry gas seal creates a film of gas between a rotating seat and a stationary face. A clean and dry sealing gas is injected between the inner labyrinth seal and the gas seal, providing the working fluid for the seal running gap. These plates hold a valve in position against an orifice in a flexible diaphragm and seal the water outlet. Dry gas seal systems for centrifugal compressors page 3. The two important things in liquid ring vacuum pumps are used to create vacuum are liquid sealent and impeller.
A sealing gas is injected into the seal, providing the working fluid for the running gap and the seal between the atmosphere or flare system and the compressor internal process gas. Gcs founded on january 1st, 2017, was previously a business unit within midwest pressure systems, inc. Holder, norbert typically, compressors with dry gas shaft seals are used in. For extended reliability filter filtered process gas clean dry seal gas is the module most importantprocess gas gas should be filtered fi fi to around 1 micron coalescing filters can be used to dry the gas heaters can be used to provide superheat heat tracing should be used to prevent heat loss. Centrifugal compressor seals are a critical subsystem, carefully integrated into the overall unit design. The dry gas seal and compressor manufacturers instructions should be strictly followed when installing, commissioning, operating, and maintaining dry gas seals and their support systems. Deluge valves are used in conditions that require for quick application of large volumes of water and, for that reason, are often integral components in fire protection systems. Specifying engineers sometimes do not give enough attention to the scope, definition and selection of the most appropriate gas seal type, its control system and auxiliaries for a given service application. The principles of operation of dry gas seal faces, the methods of seal gas control, slow roll and challenging sealing environments.
Wet seal degassing recovery system for centrifugal compressors 2014 2 one partner has reduced methane emissions from centrifugal compressor seal oil degassing by separating gas from seal oil in a small separatordisengagement vessel and routing it back into the compressor suction, to high pressure turbine fuel gas, or to low pressure fuel. For turbocompressor applications, the seal panel, the seal piping arrangements, and the seal vent system details are critical for reliability, performance, safety and operation of dry gas seals. The scope of supply is virtually unlimited and fully automatic. This instructorled 4day course introduces the principles of dry gas seals and seal support systems for centrifugal compressors, including dry gas seal installation, operation and maintenance. Fire water sprinklers working principle instrumentation tools. Dry gas seals are now accepted world wide as a mature product handling gases on a very wide variation of plants and compressors.
The panel includes filters, pressureflow control valves and various instruments to condition, control, and monitor the gas into and out of the dry gas seals. The use of dry gas seals in process gas centrifugal compressors has increased dramatically over the last. Industrial mechanical seal basics seal selection process. Sealing is aided by the hydrodynamic action caused by the rotating shaft, which creates a slight pump action. Inadequate fuel gas pressure during start up typical conditions on. In this post, well try to answer that question in more detail. If this drying gas has a deleterious effect on the product, then an indirect type of dryer can be supplied. Dry gas seal system centrifugal compressor,dry gas seals are an integral. Dry gas seal operation and maintenance on globalspec. Influence of the groove width on the aerostatic dry gas seal. The recommended technique of evaluation of the c ondition of the dry gas seal is by monit.
The finding showed that approximately 80 percent of compressor failures were due to seal oil system faults. The nde primary vent high pressure indicated the high leakage of the dry gas seal. System designs can be based on differential pressure control, flow control or other control methods. Dry air or a dry gas mixture is compressed from vacuum to atmospheric pressure in a liquid ring pump much the same way as it would be in any other displacement type pump, except that there is less of a temperature rise of the gas stream through the pump. The dry gas seals employed in dresserrand centrifugal compressors represent a significant advance in shaft. Dry gas seals are mechanical seals but use other chemicals and functions so that they do not contaminate a process. A free powerpoint ppt presentation displayed as a flash slide show on id. The vacuum is created in the vacuum pump by using a liquid seal,the. These seals are typically used in a harsh working environment such as oil exploration, extraction and refining, petrochemical industries, gas transmission and chemical processing. Dry gas seals are basically mechanical face seals consisting of a mating rotating ring and a primary stationary ring during operation, grooves in the mating ring. Dry gas seals 101 presentation free download as powerpoint presentation. To be able to generate enough heat to dry the concentrate air must. Aerostatic dry gas seal has attracted more and more attention because of its advantages with low friction loss, low heat generation, large opening force and high gas film stiffness at lowspeed operation situation.
The meticulous multimedia approach gives a virtual description of mechanical seal maintenance procedures and is sure to be a handy reference for seal repair. Inboard of the dry gas seal is an inner labyrinth seal, which separates the process gas from the gas seal. Humid air or gas mixtures containing condensable vapor behave quite differently. Vacuum systems are not easily converted from wet to dry by simply changing the pump from a wet to a dry style. The gaspac seal is a proven design using either the bidirectional tgroove technology or the advanced pattern groove apg technology.
Process gas seal support gas seal support systems are designed, built and tested per api 614. A dry gas seal consists of a rotating, hardface mating ring with either a machined or etched circumferential spiral groove pattern and a primary stationary ring in softer ma terial. Dry gas seals for compressors and auxiliary equipment, sms and. In this video, you can learn about all types of seal used in centrifugal compressor. The permian basin in west texas and eastern new mexico is one example of how john crane uses type 28 vl dry gas seals to seal supercritical co 2 for eor applications. A convergence of technologies and experience from the trusted names in gas seal and system manufacture, application, and retrofitting, our heritage durametallic. Centrifugal compressors working principle the working principle is based upon imparting kinetic energy to a fluid stream and conversion of this dynamic energy into static energy, i. Between seal gas components and gas seal gas seal panel components materials, such as a reaction between sulfur present in the seal gas stream and nickel present in the rotating ring. Drying may be by hot air or exhaust gases from other operations. Dry gas seal system design standards for centrifugal. Dry gas seals are an integral part of modern centrifugal compressors.
Scribd is the worlds largest social reading and publishing site. This greatly increases reliability and reduces seal maintenance to a minimum. This paper proposes a set of gas seal system design standards for process gas centrifugal compressors on the basis of safety, reliability, and economics. Numerical simulation on flow field of aerostatic dry gas seal. There are two basic types of gas seal systems differential pressure d p control and flow control. The mechanical seal basics training program covers a large range of seal types like pusher seals, nonpusher seals, cartridge seals, split seals, double seals, tandem seals, dry gas seals, spring seals, bellow seals, etc. Flowserve offers a springenergized oring seal within regular operating range, and a springenergized ptfe jring seal for extended operating range. When the space is hot and the fusible solder melts, the plates fall apart, the valve drops and water flows to the deflector to cause a water spray over the.
Learning is through an effective blend of classroom theory sessions and practical, handson activities. Deluge valve working principle instrumentation tools. Centrifugal compressor and dry gas seal system for use in. 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. A multistage centrifugal compressor has primary dry gas seal means for preventing leakage of working gas from a machine inner side, and secondary dry gas seal means for backing up the first dry gas seal means. Mechanical seal working animation types of mechanical seal. The leading manufacturer of dry gas seal boosters gas compression systems, inc. Key considerations for dry gas seal performance flow. The advantages of dry gas seals over wet seal systems can be defined as follows. Dry pumps reduce the risk of system contamination and oil disposal compared to wet pumps. As a contactfree sealing device, the gas seal does not require any maintenance of the cartridge itself.
Dry gas seal applications for high pressure youtube. This paper presents the philosophy of one centrifugal compressor and dry gas seal original equipment manufacturer oem in regard to gas seal system design standards. The development and introduction of dry gas seals solved several seal problems of compressor users. We are the leadingedge service provider for dry gas seal retrofits, high end compressor seal troubleshooting, seal support engineering and world class gas conditioning systems. John crane gas sealsgas seals and their application for maximum. The influence of the radial groove width ratio, bw, on the performance of the aerostatic dry gas seal has been investigated by an analytical method by solving the ns.
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