New federal air quality laws limiting hydrocarbon emissions encourage the use of tandemtype seal systems. The stationary part of the seal is fitted to the pump housing with a static seal this may be sealed with an oring or gasket clamped between the stationary portion and the pump housing. The success story of having a mechanical seal refurbishment facility at 9mmtpa grass root. Reversed balanced mechanical seals are externally mounted balanced seal with oring as secondary sealing. Eliminate mechanical seal failure in a crude distillation unit.
In response to this large number of fatal or catastrophic incidents, osha initiated cpl 0300004, the petroleum refinery process safety management national emphasis program nep, in june 2007. He is also having experience in nondestructive and destructive testing use during construction of big oil and gas processing and production complex. This would necessitate a special arrangement and would not conform to din 24960. The root causes of failure for the mechanical seals for 16 hot hydrocarbon service pumps with operating temperatures in excess of 250c are discussed.
There are various types and arrangement of the mechanical seals being used for the centrifugal pumps. The ekk group supply mechanical seals, accumulators and various other products for plant equipment used in the steel industry. Mechanical seals are used in wide range of equipment to seal a rotating shaft to a casing. The ekk group provides various products including mechanical seals for use in pumps and compressors incorporated in various plants in the oil refinery and petrochemical industries. Dec 14, 2020 on the contrary, non mechanical valves are robust due to the absence of moving parts, inexpensiveness in construction and simplicity in operation basu and cheng, 2000, cheng and basu, 1999. Careful consideration must be taken when selecting pumps and mechanical seals for these products. The new t4111 single use elastomer bellows cartridge seal was designed to make life easier for maintenance engineers in the food and beverage, mining, and wastewater industries. It covers the various mechanical seal types and explains the mechanical seal working in detail. Determining the mechanical seal design and the appropriate materials for each application is essential in order to cut costs.
This seal system does not use any circulating seal oil. An alternative to the traditional wet oil seal system is the mechanical dry seal system. Utilities and process equipment shall be considered part of the process if in the event of a failure or malfunction they could potentially contribute to. Smarter seal solutions achieving reduced machinery. Advancements in mechanical sealing api 682 fourth edition. All the above gives rise to extremely demanding requirements for the mechanical seals and for the auxiliary elements supplied with them. The mechanical seal training course has been developed to assist in maintenance and operation. Mechanical seal products and services catalog flowserve. May use a liquid buffer, gas buffer, or no buffer fluid. To do this, it was necessary to categorise refinery applications into a number of services.
Mechanical seals the shaft seals used in rotating machinery such as pumps, hydraulic turbines. Understanding mechanical seal support types suitable for. Internal structure of pump a pump is a machine that works to move fluids, as in lifting a liquid to its inside. Purposes and function if mechanical seals are used in pumps or other machines like mixers or dryers, often a barrier buffer system with a suitable medium is necessary. The two most common devices for restrict ing leakage around rotating shafts are packing and the end face mechanical seal often abbreviated mechanical seal or simply seal, see figures l and 2. Because of problems when converting from packing to seals, the seal specifications just. Mechanical seals ekk technologies eagle industry co. Oil refinery pumps almost universally use mechanical seals. Mechanical seal installation location in pump a mechanical seal is installed on the impeller rotating shaft. The mechanical seal works through the use of two very flat generally within 3 light bands flat lapped faces, which make it difficult for leakage to occur beyond a vapor. Inherent in api 682 was the target that mechanical seals. Method for reducing natural gas losses volume of natural gas savings mcf. The mechanical seal mechanical seals have the purpose of preventing leakage of a fluid liquid or gaseous through the clearance between a shaft and the fluid container. Most chemical duty pumps are thought of as standardized units.
Most mechanical face seals use a solid wave or coil spring housed in a stamped or machined housing. From expert consulting and engineering up to modular. The rotating and the fixed faces are the two vital parts of the mechanical seals. Considerations for dual pressurized gas seals in pump. The following are example uses of a mechanical seal in a pump. Mechanical seal technology and selection eagleburgmann. Packing is the older of the two sealing methods and. Oecd members represent an approximate 18% of global refining capacity. Gaskets are commonly produced by cutting from sheet materials. Figure 127 shows a tandem seal assembly with bellowstype seals for hot oil service. Flowserve seals and support systems for the refinery industry satisfy all requirements of the latest edition of api 682. Above the limit shown, it is necessary to stationary mount the seal unit and use a rotating seat. Prior to joining john crane, he was a rotating equipment engineer for a major refining company at a large integrated refinery and petrochemical company.
Packing seals use ropelike materials that wrap around the shaft of a pump, filling in dead space and minimizing fluid loss. How to respond to mechanical seal leakage in a centrifugal. As part of their educational mission they develop publications such as the mechanical seal handbook, a primer intended to complement the more detailed manufacturers documents produced by the member companies. This articles describes some of the commonly used mechanical seal types like cartridge type mechanical seals, balanced type, unbalanced type, conventional, pusher, and nonpusher type of mechanical seals. As this process continues, the leaking equipment becomes a. A mechanical seal has 4 main sealing points indicated by orange circles as per figure 3. Utilities and process equipment shall be considered part of the process if in the event of a failure or malfunction they could potentially contribute to a major incident. As this process continues, the leaking equipment becomes a significant source of voc emis sions. Petroleum refinery activities including use, storage, manufacturing, handling, piping or onsite movement that involve a highly hazardous material.
Various seal face material and oring can be used for wide range of application. The manufacturer listings are alphabetical, refer to pages 7. The principle of the mechanical seal is to use two replaceable antifriction mating ringswith, to provide sealing surfaces at the point of relative movement. The maximum seal life achieved did not exceed 6 mos, which was much shorter than the american petroleum institute api 682 advancements in mechanical sealing goal of 3 yr of seal life. Plan 01 is an internal recir culation from the pump discharge area of the pump into the seal chamber, similar to a plan 11 but with no exposed piping. These seals, which use various face patterns to achieve liftoff, offered a safe, reliable, and simple arrangement to contain toxic and hazardous hydrocarbon gases. Capture the growth from firstfit installations and service the installed base. While these parameters capture the significant design factors for a seal, the. Do you have a mechanical seal refurbishing shop in your complex. This design provides sealing without product contact with the metal seal parts. Mechanical seal installation location on shaft mechanical seals are mostly comprised of two rings. Reliable seals for high temperature oil and light hydrocarbons now exist.
The seals are arranged by shaft size from smallest to largest. They have less mechanical loss than oil seals, improving efficiency. The seal between the rotating 3 and stationary faces 1. A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression gaskets allow for lessthanperfect mating surfaces on machine parts where they can fill irregularities. The mechanical seal division of the fsa is one of six with a speci. An eroded, worn, or fretted dynamic oring or gasket as the mechanical seal moves. But the consequences and effects may be more easily evaluated, and an increase of the seal s life time may be achieved in specifi c applications. Dry seals operate mechanically under the opposing force created by hydrodynamic grooves and static pressure. Basic designs of mechanical seals vary, but all have a lapped seal face between a stationary element and a rotating seal ring ramsden, 1978. The course, designed with extensive graphics and animation, gives a virtual practical exposure on.
Since our subject is dealing with pumps, lets first explore a basic. Their designs allow for relatively easy changeouts between design options and manufacturers. The root causes of failure for the mechanical seals. One face is stationary and the other rotates with the shaft. Dual seals on the rise for refineries and petrochemical plants. Eagleburgmann offers a wide range of high quality mechanical seals and supply systems which fully comply with api 682. Given the general geometry of a mechanical seal, anywhere that theres a gasket or an oring, there ensues a potential leak point. The garlock family of companies has developed countless products including gaskets and sheet material, metallic gaskets, resilient metal seals, klozure oil seals, bearing isolators and mechanical seals, compression packing, expansion joints, elastomer seals, hydraulic components and tools. Unlike an oring seal, the hydraulic diameter of a bellows seal is not a fixed geometric value. Sealing competence for refining technology eagleburgmann. Type 502 elastomer bellows seal speed limits rotating seals may be used at speeds up to 4000 rpm according to seal size.
The seal between the stationary member 1 and stuffing box face, i. In part 1 of our series on double dual seals, we discussed the benefits of dual seal design and when to use it. The rotating face is connected to the rotating shaft while the fixed face is connected to the pump housing. As part of their educational mission they develop publications such as the mechanical seal handbook, a primer intended to complement the more detailed manufacturers documents produced by. A sts mechanical seal reduces process steam loss and improve turbine efficiency. Mechanical seals are designed to overcome these drawbacks.
Between the two faces of the mechanical seal the secondary seals, known as shaft and insert mountings, like orings, wedges and vrings are inserted. To install a seal, the pump would have to be taken offline and disassembled. The mechanical seals help sealing the rotating part of the shaft against the stationary part of the pump housing. Dry gas seals are noncontact, dry running mechanical face seals that use a sealing gas to create a barrier between the process gas and the atmosphere. To satisfy the refining and petrochemical industries need to reduce gas emissions, dry gas mechanical seals were first available in ig compressors in 1965. Importance of having mechanical seal refurbishment facility in a refinery complex, supported by interesting case studies on critical mechanical seal failures.
Inprocess refinery end products and finished marketable refinery end products diagram api for valves the oil and gas industry does not use a universal api specification for valves like they have on pumps and seal systems. This improving the reliability of mechanical seals michael huebner flowserve corp. These pioneering techniques have led to sophisticated seal face topographies and innovative microfeatures that can be designed to boost. Company computers, telecommunications equipment, manual. Rely on excellence barrierbuffer media for mechanical seals. The most effective method of preventing the leakage of the fluid from the centrifugal pump to the external surroundings is using the mechanical seals. Dirt or contamination in between the mechanical seals. With a lower k value, the safety against thermal overload will increase, but the mechanical seal may also lift off more easily. The other highest type of fa ilure is the malfunction 23% due to unknown. The purpose of api 682 is to assist in the selection and operation of end face mechanical seals in centrifugal pumps. With no contacting surfaces, dry gas seals are extremely reliable, reducing downtime and unplanned maintenance expenses. If you are unable to identify the seal, it will be necessary for you to.
Double mechanical seal arrangement options double seals. These seals are suitable for handling most of the corrosive media with some solid content. Design, construction and operation of the floating roof tank. The american petroleum institute api has approximately 500 technical standards for processes and components. Single seals without connections sno, with flush sn and with quench combined with lip seal qn or throttle ring tn additional variants available for ansi pumps e. Increase seal chamber pressure and fluid vapor margin.
In a single mechanical seal application, the rotating seal ring. John crane mechanical seals, seal support systems, filtration systems, couplings. Mechanical seal installation location in pump a mechanical seal is installed on the. Pumps shaft sealing systems for centrifugal and rotary pumps api standard 682 is the standard about end face mechanical seals. The purpose of the standard was to capture proven solutions to the most common sealing applications seen in refineries.
Lts or lqt reservoirs, or elements such as cyclones. He is mechanical engineer and certified project management professional pmp from pmi usa. Two seals per cartridge assembly with a chamber between the two sealsat agreaterpressure than the pump seal chamber. To replace carbon ring seal which is normally fitted to steam turbine, sts mechanical seal has been developed in conjunction with a major oil refinery. There was no attempt to cover every type of rotating equipment, mechanical seal, or application. In part 2, were taking a closer look at the various rotary and stationary double seal arrangement options configurations, and how to maximize their success.
Converting from packing or component seals will generate a significant cost savings. The seal between the rotating member and shaft or shaft sleeve 4. Dual seals on the rise for refineries and petrochemical plants 5 advantages of investing in dual pressurized seals the growing interest in dual pressurized seals for refinery and petrochemical applications is directly related to the benefits they offer compared to single seals and dual unpressurized seals. Do you have a mechanical seal refurbishing shop in your. The application of sealing systems conforming to the latest api 682 standard is an essential condition.
The 1st edition also provided a seal selection guide covering typical refinery applications. Contact us to find out more about the differences between the 3rd and 4th edition, such as what will be the impact of the new edition regarding your plant, equipment, and applications. If these seals are not properly designed, constructed, instal led, and mainta. It is often used in chemical applications where the seal must be mounted on a nonmetallic shaft. A mechanical seal pump could potentially save you a lot of annual costs.
Browse through our comprehensive range of api 4th edition seals and supply systems, use the download for offline reading, or order free literature and other useful material. Dodd of chevron, came up with a general plan and the american petroleum. These seals often use two rotating seal faces and two stationary seal. This provides excellent leak and contamination protection.
As mechanical seals can be used to seal a myriad of different products on an equally vast array of equipment, we will be primarily focusing on the use of mechanical seals on rotating shaft pumps. Seal support systems are paired to the specific process conditions and the mechanical seal. The training course also includes an api682 guided seal selection tool and a troubleshooting guide. Flowserve seal product portfolio flowserve corporation. The stationary part of the seal is fitted to the pump housing with a static seal this may be sealed with an oring or gasket clamped between the. This valve prevents damage to the hydraulic system when the machine is being towedpushed short distances without use of the engine. Plan 03 plan 65b plan 66a plan 66b what seal flush from pump discharge through orifice. Lvalve, jvalve, vvalve, nvalve, seal pot and loop seal ls are some of the successfully operated non mechanical valves in the industry. Temperature ranges of sub zero to 800f, low specific gravity hydrocarbons, products handled near their vapor pressure, and flammable liquids all present unique challenges for proper mechanical seal selection as well as dependability. Mechanical face seal replacement how to use this catalogue locate the manufacturer of the equipment. Eagleburgmann supplies the full range of mechanical seals. By 1954, mechanical seals were used with such regularity in the refining and process industries that the american petroleum institute included seal specifications in the first edition of its standard 610, centrifugal pumps for general refinery services. 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.
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