Dry gas sealing has become a catchall term for a variety of seal face lubrication mechanisms, but not all dry gas seals are created equal. Seals and information shown represent standard configurations of popular seals for the wastewater treatment industry. The company offers various products, including cartridge mechanical seals, component seals, bearing protection, gas seals, seal support systems, and gland packing. Introduction to failures failure of the mechanical shaft seal is the most common cause of pump downtime. Beyond gas savings, dry seals also yield significant operational and maintenance savings compared with wet seals. The sealing surfaces are separated from each other by a fluid film liquid or gas during shaft rotation and in principle run without contact and thus minimal wear under these conditions. Dry gas seals are designed with many of the basic characteristics of liquid mechanical seals and can therefore be potentially subject to similar failure modes. These seals are generally used in sewage applications and waste water pumps. John crane gas sealsgas seals and their application for maximum reliability 2. Mechanical seals for compressors flexaseal has designed and manufactured many standard and custom sealing solutions for a wide range of compressor brands and models. In need of reliable dry gas seals for compressors, turbines, process pumps and driven machinery for global process industries that will increase efficiency in your. Mechanical seals market global industry analysis, size and. One of the materials used in many mechanical seal systems is based on the fourth most common element and the basis of. Dry gas seal systems for centrifugal compressors page 2.
The vast majority of failures of mechanical seals can be attributed to the system in which the seal is installed, not the seal itself. It is not unusual to find large process gas machines still in service four or more decades after commissioning. Espo pipeline, russia 60 dual seals and 64 single seals for highpressure crude oil pipeline pumps in use. Type 28exp dry gas seals john crane mechanical seals. It is a proven rotating groove technology that reduces steam leakage, compared to traditional sealing devices. The mechanical seals course consists of four lessons designed for persons with a basic understanding of the operation and maintenance of pumps, agitators, and rotating equipment. Dry gas seals are noncontacting, dry running, mechanical face seals comprising a. An effective dry gas seal offers noncontacting, liquidfree operation, eliminating friction that contributes to excess heat and hampers system performance. For dry gas seals in rotary compressors equipment in gas production installations, elastomeric rings are used as secondary seals. Learning is through an effective blend of classroom theory sessions and practical handson exercises. Chesterton gas seals offer advanced, patented sealing technology in a compact and easytoinstall design. A sealing system for hydrocarbons must often make allowance for partial dry running due. However, dry gas seals figure 1 are prevalent in new installations. Pss iii a balanced, radially split end face mechanical seal that has seal faces, gaskets, and setting devices unitized.
This method used as a static leak test on large mechanical seals is usually unable to detect a leak, as it is generally impossible to view the inside of the mechanical seal, e. Robert flitney, in seals and sealing handbook sixth edition, 2014. Continuous gas supply when compressor is operating slowly or is stopped. The reason lies in the previously discussed theory of lubrication. As the seals gain in popularity know their advantages and disadvantages. As part of the german freudenberg and japanese ekk group, eagleburgmann is one of the worlds leading providers of industrial sealing technology. Dry gas seals for lng compressors modern pumping today. Other types of gas seals such as double opposed are not considered.
Tandem seals consist of a primary seal and a secondary seal, contained within a single. Norway 35 oil platforms offshore are equipped with seals from eagleburgmann. Flowserve represents not only a collection of trusted products, but also a single global source that can reduce your total cost of ownership. For compressors, the two points where the rotating shaft passes through the external case need to be sealed to prevent th. The three principal types of dry gas seals for turbomachinery applications are discussed in the following paragraphs. The information found in dry gas seals handbook will help you make informed decisions regarding the.
Understanding the dry gas seal ing technology and optimizing the seal selection for a given set. The initial closing force ensures that the seal will function properly from startup. Shaft end seals are provided to restrict or prevent process gas leaks to the atmosphere or sealing fluid leaks into the process gas stream. 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 faulttolerant design of our gas seals offers higher reliability, reduced gas consumption requirements, and allows for gas supply disruptions. As part of the german freudenberg and japanese ekk group, eagleburgmann is one of the worlds leading. A commonly reported rootcause for seal failures has been low pressure of seal gas at startup, which resulted in dirty gas moving to the dry gas seal from the compressor casing. Aura the next generation of john crane gas mechanical seals duration.
For a more complete description of dry gas seal principles of operation, see shah 1988. The ability of a mechanical seal to meet its performance objectives depends upon a wide range of factors involving equipment design, operating conditions, and support systems. To prevent this, to prevent this, s e p arati o n ga s i s inj e ct e d b e t ween t h e s ea l a nd b e a ring. Wet seal to dry seal conversion flow control network. Inadequate fuel gas pressure during start up typical conditions on inboardoutboard seal will include running. This is evident by the latest advances weve made in seal face technology and seal design. Aesseal produces a full range of compressor dry gas seals, pump dry gas. A dry gas seal is a type of mechanical seal used to contain gases without incursion from contaminants or inadvertent release of the gas into the surrounding environment. A dry gas seal is a type of seal used in large rotating equipment to keep the process fluid from leaking into the atmosphere. Dry gas seals dgs are basically mechanical face seals consisting of a mating rotating ring and a primary stationary ring. Dry gas seals are in used in compressor stations, processing plants, refineries, chemical plants, and more. Mechanical seals are designed to produce an acceptably low l evel of leakage to function effectively. Liquid seals must always have a film of liquid present between the seal faces. Many continue to operate well with wet seals as originally specified.
It is common practice to replace dry gas seals at scheduled overhauls of the compressor sometimes left to the operators discretion, but typically occuring at fiveyear intervals. Dry gas seals operate with clearances measured in microns, much less than the thickness of a human hair. Components dry gas seals dry gas seals, an alternative to isosleeve and isocarbon seals, eliminate the need for oil supply systems. As versatile as the requirements of the oil and gas industry. For double mechanical seals backtoback en specifies the short type only. To reduce the volume of gases containing volatile organic compounds leaking to atmosphere, environmental agencies have instituted regulations limiting voc emissions. A representative layout of a dry gas seal assembly and basic seal parts are shown in figures 4 and 5. While dry gas seals can be very problematic if not properly applied at the time of plant, process, andor compressor design, the many successful installations are a testament to how troublefree these devices can be when properly applied. Packing although mechanical seals had been around for many decades, by 1955 industry had converted only a small percentage of pumps from packing to mechanical seals. Dry gas seals dry gas seals are available in a variety of configurations, but the tandem style seal figure 1 is typically applied in process gas service and is the basis for this paper. The advantages of dry gas seals over wet seal systems can be defined as follows. Apr 27, 2011 common dry gas seal failures are discussed below along with their causes and remedies. John crane type 28st dry gas seals ensure reliability and uptime in missioncritical applications.
Dry gas seals are noncontacting mechanical seals, which eliminates the issue of seal wear. Inboard of the dry gas seal is an inner labyrinth seal, which separates the process gas from the gas seal. When operating, lifting geometry in the rotating ring generates a fluiddynamic lifting force causing the stationary ring to separate and create a gap between the two rings. 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. There are many different designs of a mechanical seal to meet specific applications. Rotech is the leading and most trusted industrial pumps, valves and seals manufacturer in canada and india.
Another cause of dry gas seals contamination is lube oil migration towards the seals. Mechanical gas seals market application publication background. Mechanical seals are used in industrial pumps, compressors, and other applications to provide a leakproof seal between component parts. Common dry gas seal failures are discussed below along with their causes and remedies. Dry gas seals for compressors and auxiliary equipment. Our dedicated teams expertise and thorough knowledge meet all the requirements and specifications of our clients. Our teams are able to recondition all types of mechanical seals, providing they are not beyond our specified point of repair. Global mechanical seals market industry analysis 20152019. Preventing dry gas seal failure in compressors part 1 august 9, 2017 this free webinar will discuss how to protect your assets, revenue and the environment by understanding common problems that cause dry gas seal failures. Scribd is the worlds largest social reading and publishing site. Symbols a area of sliding face a h area hydraulically loaded by medium pressure b width of sliding face. Double tandem mechanical seal of 2tm series double tandem mechanical seal of 2tmt series applied in case where single seals can not be applied because of necessity to provide the required level of safety hot oil, flammable and toxic. Theoretical lifetime is limited only by the secondary sealing elements usually orings or polymerbased seals whose lifespan can be as long as 15 years.
New oil and gas exploration activities, coupled with extensive investments in refineries and pipelines is escalating the growth of the global mechanical seals market. 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 separation gas should be filtered to 5 microns solid particles and should be 99. Aug 02, 2017 dry gas seals are an integral part of modern centrifugal compressors. Dry gas seals can eliminate some of the conventional prob lems associated with seal oil systems. To install a seal, the pump would have to be taken offline and disassembled. Methane content of natural gas switching from wet to dry seals would yield half the savings of doing the same for a beam type compressor. A mechanical seal can be supplied as a preassembled cartridge or in separate components. The shaft seal is exposed to widely varying operating conditions. Mechanical seal technology and selection eagleburgmann.
Dgs application rangejohn crane dgsoperating range temp. Mechanical seals a mechanical seal is a device which helps join systems or mechanisms together by preventing leakage e. Clearance seals labyrinth and restrictive ring seals oil seals mechanicalcontact and. A guide value for the detection sensitivity achieved by this method is 0. Increased safety, lowered maintenance and improved reliability are key considerations for retrofitting with gas seals. This service will give your mechanical seal a new lease of life, and can prove to be a worthwhile cost saving exercise for any business. The mechanical seals are highly resistant to chemicals, further increasing the reliability of cobra vr dry screw vacuum pumps. Eagleburgmann dry gas seals for lng marine and onshore. Top 6 vendors in the mechanical seals market from 2017 to. The product for the most challenging and hostile environments with proven and independently audited performance to 425 barg. The revised api 682 mechanical seal standard upstream pumping. Such seals are available for use with a variety of compressed systems, including in harsh environments where other seals might be prone to failure. Established in 2002, we offer the largest series of pumps, valves, and seals.
Top 6 vendors in the mechanical seals market from 2017 to 2021. This instructorled course introduces the basic principles of mechanical seals and seal support systems, including both wet seal and dry gas seal technology. Inadequate fuel gas pressure during start up typical conditions on inboardoutboard seal will include. Pdf centrifugal compressor spiral dry gas seal simulation. Instead the torque is driven along the rubber bellow which fits on the shaft. The facility has a total of 95 type 2800 dry gas seals in various pumping applications. Dry gas seal applications for high pressure youtube.
How gaslubricated mechanical seals work unidirectional vgroove gas enters into the threedimensional v. Many large pumps or compressors contain mechanical gas seals that operate as non contacting, dry running seals. Since its introduction in 1994, api 682 has become the standard that sets the global tone for the procurement and operation of seal and supply systems for centrifugal pumps in the oil and gas sector as well as in the petrochemical industry. The benefits of dry gas seals are such that conversions from traditional oil seals to dry gas seals may be advantageous to compressor operators. Included in this list is the selection of the materials of construction of the seal. Every day our solutions move even the most hazardous fluids and gases safely and securely. Type 28 compressor dry running gas seals have been the industry standard since early 1970 for gas handling turbomachinery.
The sts mechanical seal has been developed in conjunction with a major oil refinery to replace existing carbon ring seals normally fitted to steam turbines. Mechanical seals first in a series by ann attenasio. However, this situation has been changing, as described below. Dry gas seal operation and maintenance on globalspec. In end or rotatingface mechanical seal designs, the initial closing force is provided by a spring component, which can be a single coil spring, multiple coil back to basics. However, endusers should ask themselves several questions before deciding to retrofit. The lessons in this course train participants to work effectively with mechanical seals. The dry gas seal is a noncontact, gas lubricated, mechanical endface seals that.
An article on dry gas sealing systems what is piping. These seals are also suitable for industrial pumps. Assembly is done in accordance with the assembly drawing. About us at the leading edge of industrial sealing technology. A dry gas seal is a mechanical seal that uses a sealing gas to create a barrier between the process gas and the atmosphere. Leadingedge, noncontacting face technologies the gas turbine industry demands seals that operate at. Outboard of the dry gas seal is a barrier seal, which separates the gas seal from the compressor shaft bearings fig. With a lower k value, the safety against thermal overload will increase, but the mechanical seal may also lift off more easily. At the same time, people are getting more and more attention on this part, the oil and gas mechanical seal has many advantages, mainly for the reliable sealing performance, a small amount of leakage, the use of a series of. Packing cartridges combine quick and easy installation with robust simple construction. Other configurations, sizes, and products are available, consult your flowserve representative for assistance. Sts adopts aesseal dry running gas compressor seal technology to provide a solution that significantly reduces the steam leakage typically associated with standard carbon ring seals. Increase in production of shale gas in developing and developed countries is a major factor driving the growth of the market.
Rhondama seals are now able to offer an expert repair service for mechanical seals. Even such gas handling machines as gas compressors often use a liquid seal with a liquid lubricating system. Generalized dry gas seal dgs as used in process gas compressors. 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. Dry gas seals are noncontacting, dry running mechanical face seals that consist of a mating rotating ring and a primary stationary ring. Dry gas seals 101 presentation free download as powerpoint presentation.
To view our current library of sealing arrangements for many of the worlds most popular compressor styles please navigate the cross reference chart as well as the product. Dry gas seals 101 presentation gas compressor scribd. The dualdam gas intensifying design comprises 5 elements which combine to. Rely on excellence competence in compressor sealing. The mechanical oil and gas seal dry gas seal and wet gas seal also has become one of the most important research topics. A mechanical seal will run in the pumped product or external source fluid.
The depth of our experience in gas turbine and other industrial applications for mechanical seals is unmatched. It is recommended to install seal gas boosters to ensure supply of seal gas during standstill and transient conditions, if a reliable source of seal. During operation, grooves in the mating ring generate a fluiddynamic force causing the primary ring to separate from the mating ring. Eagleburgmann mechanical seals combine the elasticity of. Dry gas seals, also known as gaslubricated mechanical seals, are the preferred solution for lng compressors in onshore and offshore applications because of their superior capabilities in reducing power dissipation and leakage at shaft ends. Drygas seals are designed with many of the basic characteristics of liquid mechanical seals and can therefore be potentially subject to similar failure modes.
Dry gas compressor seals piyush shah group manager, type gas. Turbomachinery sealing solutions flowserve corporation. General installation and operating instructions for. Gas up your sealing knowledge as users become more familiar with gas seal technology and its advantages, gas seals are being applied to a wider variety of applications and equipment than ever before. Many individual internal and extern al factors, as well as interactions between them, will affect the rate of seal leakage. A dry gas seal is essentially a mechanical seal with a rotating mating ring and a stationary seal ring. These seals are manufactured by full automated assembling lines at our global production sites, and has high market share in worldwide specifically in the category of seals for automotive water pumps. Department of mechanical engineering, university malaya, 50603 kuala lumpur, malaysia. Dry gas seals are noncontacting, dryrunning, mechanical face seals comprising a. Dryrunning seals and gasseals operate on different principles and shall be considered further on. Dry gas seals dgs used in ultrahigh pressure gas reinjection systems are setting a new standard in offshore, deepwater applications. Schoenherr, fundamentals of mechanical end face seals, in reprinted from iron and steel engineer, printed in engineered fluid sealing john crane, inc.
An excellent thermal balance ensures low gas temperatures within the compression chamber in line with atex standards. Drygas mechanical seals set a new standard in deepwater. Much of what has been discussed in this chapter thus far is equally applicable to gas and liquid seals. Type 28st dry gas seals john crane mechanical seals. Dry gas seals are noncontacting, dryrunning mechanical face seals that consist of a mating rotating ring and a primary stationary ring. The number one reason for retrofitting conventional wet seals to dry gas seals is reliability.
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. Gas seals must always have a film of gas present between the seal faces. Mechanical seals of 2tmx type are used together with heat exchanger btn12d35k, sappd 1. Drygas seals dgs used in ultrahigh pressure gasreinjection systems are setting a new standard in offshore, deepwater applications. Mechanical seals according to en 12756 code system for single mechanical seals there is a distinction drawn between standard n and short k types. Sometimes operating conditions change to become quite different from the specific conditions for which the seal was intended.
The functions, operation, and repair of common mechanical seals are demonstrated. Dry gas sealing systems for oil sands pumping applications. Key considerations for dry gas seal performance flow. We are committed to providing the latest technologies and designs in order to provide our turbo machinery customers within global energy industries with the solution. Repacks sealing solutions are used extensively in highend mechanical seals in single, tandem and double arrangement, as used in turbomachinery and other rotary processing equipment where reliability is paramount and the cost of downtime and consequential losses far outweighs that of using our suitably engineered, flawlessly executed, highperformance products.
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