The abcs of mechanical seal leaks and impact on thermal fluid operations sat d d o seal s r s d primary ring mating ring o gland plate stationary s rotating typical single shaft seal the need to leak mechanical seals must leak to operate properly. Mechanical seals for rotating shaft applications move the point of the seal away from the shaft to specially designed sealing faces that gradually wear down. Pdf unique failure mode for double mechanical seals api. It is ideal for seals subjected to intermittent, short periods of time when product liquid does not provide adequate film between the seal faces. Since our subject is dealing with pumps, lets first explore a basic. Seals not only reduce leakage between the shaft and diaphragm but also between the shaft and casing as shown in fig. We will manufacture and design seals to suit any customer requirements. Grundfos type designation mechanical shaft seals are classified according to a grundfos type designation based on the design of the shaft seal. In the late 1920s, a self contained shaft seal was created from oil resistant leather assembled into a metal case.
Mechanical seals are one of the most effective ways of sealing rotating shafts, consisting of two lapped faces arranged perpendicular to the axis of the rotating shaft. It reduces leakage between the pump and the surroundings to an absolute minimum. Generally unbalanced seals have good performance when subjected to vibrations, misalignments or cavitation. These mechanical seals are applied in a wide range of industries, including petroleum refining, chemical, paper milling, steelmaking, water supply and sewerage, food processing and ship building. Mechanical seals are used in industrial pumps, compressors, and other applications to provide a leakproof seal between component parts. A mechanical seal is installed on the impeller rotating shaft. A few basic components and principles in mechanical seal design contribute to a working seal at the interface of the rotating shaft and stationary pumpmixer seal chamber housing. An inventory of replacement seals is kept packaged and ready to ship for the following. Mechanical seal leakage in pumps how much, if at all, mechanical seals do, must or must not leak is a controversial subject for which there are few clear answers. This prevents the liquid from leaking through the clearance between the pump body and the shaft. The type 16 incorporates the same crimped head design and hextorque drive as our. Replacement shaft seals refrigeration compressors and pumps.
Critical seal design tolerance charts fda compliant seals. The shaft needs to be locked both radially and axially to prevent movement. The shaft seal is exposed to widely varying operating conditions. Before the advent of mechanical seals, pump users relied primarily on rope or braided style packing to achieve a. Klozure is a global company with installations worldwide, solving demanding applications big and small. A mechanical face seal is a great choice but many come with hidden design problems. Remove the stationary mating ring of mechanical seal 433.
To install a seal, the pump would have to be taken offline and disassembled. Advancements in mechanical sealing api 682 fourth edition abstract api 682 iso 21049 is the leading document for mechanical seals in petrochemical, chemical, and pipeline services. Seal mechanical seals, there is no more expensive shaft or sleeve replacements. 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. Mechanical shaft seals ua type item 1 cup gasket nbr 2 stationary face ceramic 3 rotary face carbon 4 bellow nbr 5 retainer sus304 6 drive ring sus304 7 coil spring sus304 8 spring retainer sus304 special requirement for material please consult our office.
A dynamic radial seals dynamic radial seal creates a. European standard en 12756 dimensions according to en 12756 european standard en 12756 defines the principal dimensions for the installation of single and multiple mechanical shaft seals into pump housings. A few basic components and principles in mechanical seal design contribute to a working seal at the interface of the rotating. One is usually stationary and seal contact pressure is applied by a spring mechanism. Hydraulic seals parker hannifin prdifa technology diision precision seals for hydraulics elastomer seals are functionally reliable components of fluid engi neering equipment and systems. These seals proved to be very effective until shaft speeds, temperatures and other parameters increased with the development of better transportation systems. Mechanical shaft seal types in this chapter, the basic working principles for single mechanical shaft seals will be put into a practical context. It has combined the aspects of seal design, testing, standardization, and applications to provide the users and oems alike with a common source of information for mechanical seals. 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. Eagle burgmann mechanical seal pdf in the united states since, eagleburgmann operates manufacturing, functions at its houston headquarters including a dynamic dry gas seal test facility. Mechanical seals technical manual brenner industrial sales. Different types of mechanical seal free download as pdf file. As a comprehensive manufacturer of pumps, torishima has never lost sight of the importance of. Mechanical maintenance entry test enabling objectives site maintenance training program page 1of 5 safety.
We believe the best way to service the end user is through our strategic alliances with distribution partners. Mechanical shaft seal types and sealing systems grundfos. Most important materials the following table shows the codes of the most important materials, selected on the basis of the grundfos range of products and their fields of application. Position 1 codes position 1 of the mechanical shaft seal variant code shows the grundfos type designation.
As seal technology has advanced, the standard has expanded to incorporate new seal designs. The variant code of mechanical shaft seals is stamped on the pump nameplate. Wherever a rotating shaft moves fluid, mechanical seals play a key role in sealing process fluids in, keeping contaminants out, or both. This article discusses a unique failure mode for double mechanical seals conforming to api standard 682pumps shaft sealing systems for centrifugal and rotary pumps. Spring retainer positions and centers the spring, aiding the concentricity between the spring and. This gives rise to the alternative name radial face seal, pump seals or packings. The materials of seal construction, particularly the sealing faces and elastomers. Mechanical seal applications mechanical seals the shaft seals used in rotating machinery such as pumps, hydraulic turbines, agitators and centrifuges play an important role in maintaining the safety and economic efficiency of machinery. A mechanical seal is a shaft sealing device, which forms a running and dynamic seal between the rotating and stationary parts of a rotary equipment, developed to overcome the disadvantages of the traditional compression gland packing. Mechanical seals were originally designed to lend a greater sealing capability than could be achieved using common packing.
Mechanical seals the shaft seals used in rotating machinery such as pumps, hydraulic turbines. This article will explain what a mechanical seal is and the key design features that make them work. Mechanical seals are usually endface seals or rotatingface seals, but in some designs they can be circumferential or even a hybrid of liptype seals. Mechanical seals for rotating shaft applications move the point of the seal away from the. Mechanical shaft seals this section briefly describes the design and elements of the mechanical shaft seal. Mechanical seals standard oem mechanical seals uk seals. The mechanical shaft seal is essentially a throttle arranged around the shaft. Sealing systems for pumpssealing systems for pumps part i presented by.
All the above gives rise to extremely demanding requirements for the mechanical seals and for the auxiliary elements supplied with them. Failure of mechanical shaft seals the knowledge link. Seals have more flexibility than packing and are able to compensate for shaft deflection, axial and radial end play, as well as vibration and wear of the sealing faces. Sometimes operating conditions change to become quite different from the specific conditions for which the seal was intended. Popular mechanical seal mating rings come in ceramic white and sintered nickeliron gray.
Selecting a radial shaft seal profile that does not allow this to happen is necessary to avoid mechanical failure. As a comprehensive manufacturer of pumps, torishima has never lost sight of the importance of mechanical seals. The face seal is designed with two finelymachined surfaces or faces located perpendicular to the shaft and pressed together to form. The seal size, design type, component materials, and housing configuration have been specifically.
Download ky type 21, john crane type 21, elastomer bellow shaft seals. Seal basics a mechanical seal is a device used to seal the interface between a rotating shaft and a stationary housing figure 1. A mechanical seal is simply a method of containing fluid within a vessel typically pumps, mixers, etc. All face seals require a secondary seal, which can be some. Failure of the mechanical shaft seal is the most common cause of pump downtime. Mechanical seals the shaft seals used in rotating machinery such as pumps, hydraulic turbines, agitators and centrifuges play an important role in maintaining the safety and economic efficiency of machinery.
This document is intended to clarify what to expect on mechanical seals found in colfax products. Materials see inside end cover of manual for the material code. Although gland packing is a very used material, mechanical seals are becoming a world standard for these reasons. This improved design allows the seal to be in field repairable. Please click on the picture to view more details please note that due to our massive product range we cannot display all our products, for any queries. Axial mechanical seals these are face type seals in which the sealing contact is between radially mounted components. Skf industrial shaft seals and accessories are divided into three main groups. Sealing systems for pumpssealing systems for pumps part i. Shaft seals are typically press fit into a housing bore and to ensure a snug fit, the seal od is produced larger than the housing bore. Shelby scottshelby scott western region john crane incjohn crane, inc. The main limitation in the application of unbalanced mechanical seals is the operating pressure. The principle of the mechanical seal is to use two replaceable antifriction mating ringswith. Remove seal cover 471 with the mating ring of outboard mechanical seal 433. Mechanical shaft seals pty ltd was established in 1989 and produce a wide range of seals to the international iso9001 quality system.
By replacing your old packing with new stateoftheart u. The standard also describes the shaft seal designation and material codes to be used. For example radial shaft seals can serve as a scraper in mechanical processes with helical movement, making them a robust and reliable component that offers great value for money. A mechanical seal, figure 1, consists of a stationary member seat. Differ ent seal types within these groups are described the skf. Rotary seals, shaft seals, oil seals ftl technology. The seals are arranged by shaft size from smallest to largest. The friction of the shaft rotating wears away at the packing over.
Mechanical seal installation location on shaft mechanical seals are mostly comprised of two rings. Lubrication solutions from specialized lubricants to stateoftheart lubrication systems and lubrication management ser vices, lubrication solutions from skf can help to. Rather than a dynamic oring which can cause wear on a pump shaft, this seals oring is static. Pull shaft sleeve 523 with the two rotating assemblies of mechanical seals 433. Advanced mechanical seals for the complete range of slurry. At high pressures, an interlocking labyrinth seal is used. Nominal diameters d1 and d10 of the mechanical seal. Mechanical seals ekk technologies eagle industry co. Depending on the pump design, there may be one or two seals on each impeller shaft. Low cost of ownership compared to traditional shaft seals, mechanical seals offer a very low lifetime cost of ownership. As previously stated, a pump with a through shaft is not leakproof. Mechanical seals move the point of the seal away from the shaft to specially designed sealing faces that gradually wear down. Less friction means valuable power savings mechanical. The seals of the industrial age were organic ropes or packings.
This is commonly seen in centrifugal pumps although this challenge also exists in other equipment such as agitators, turbines, compressors, centrifuges, and blowers. John crane type 21, ky type 21, elastomer bellow shaft seals. The chapter describes mechanical shaft seals used in grundfos pumps as examples of the variety of shaft seal solutions for different applications. Vessel atmosphere wall shaft process fluid leakage. Mechanical seal technology and selection eagleburgmann. 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.
Single and double lip radial shaft seals rated for pressures up to 90 psi. This design provides an extended service life compared to a lip seal that contacts the rotating shaft directly. All rotary shaft seals enable frictionfree operation by preventing lubricant from leaking from the assembly, thanks to a clearance gap between the shaft and the housing. Lts or lqt reservoirs, or elements such as cyclones. Fitting is simple with the seal already preloaded and set in the factory ready for use. One face is fixed to the equipment casing or vessel, while the other is fixed to the shaft. Replace packing with a mechanical seal and avoid expensive shaft or sleeve replacements. Introduction to failures failure of the mechanical shaft seal is the most common cause of pump downtime. The sld is proven to greatly extend flushless seal life in harsh slurry conditions. Their advanced level of sealing technology is the result of many years of development and field experience gained in the various sectors of mechanical. Axial clamp seals are designed for large and very large shaft diameters. No rubbing friction between shaft and seal parts replace packing with a mechanical seal and avoid expensive shaft or sleeve replacements. The seal between the rotating member and shaft or shaft sleeve 4. The part of the coupling that actually transmits power and rotation from one shaft to the other shaft is.
A mechanical seal consists of 2 principle components. Mechanical seals are typically used in applications for superior sealings. This allnew cr seals handbook from sf combines or best ideas and insihs from he ast and he resen we hoe i beomes yor. The chapter describes mechanical shaft seals used in grundfos pumps as examples of the variety of shaft seal. Must be finished in the same manner as the rotary face. Mechanical seals have the purpose of preventing leakage of a fluid. The shaft has teeth that interlock with the seal fig. Mechanical seals for pump shafts provide the best possible seal for a rotating shaft. Before the advent of mechanical seals, pump users relied primarily on rope or braided style packing to achieve a seal around the shaft. Increase productivity and process reliability, and reduce total cost of. Different types of mechanical seal pump heat transfer scribd. One of the two faces rotates rotary with the pump shaft and the other face does not rotate stationary.