mechanical seal material

mechanical seal material

Mechanical Seal. However the longer you keep your pump in service, the more cost effective a mechanical seal can be. Things to Consider while selecting a Mechanical Seal Liquid. To avoid this, it is generally practical to apply a hard vs hard face combination in higher viscosity fluids. It is even more intimidating knowing that the wrong combination of materials may lead to premature seal failure, which in turn leads to significant costs due to replacement of the seal, downtime of the pump, and potential damage caused to the equipment. Special considerations are features added to seal faces intended to change the lubrication mode toward something that achieves the desired performance of the seals. This evaluation should examine if the strength of the material is sufficient enough to prevent face fractures, especially if the higher pressure is on the inside of the face. The seal between the stationary member (1) and stuffing box face, i.e. แมคคานิคอลซีล จัดจำหน่ายโดย ซีลไวส์ มี แมคคานิคอลซีล ทุกแบบ ทุกชนิด ทุกประเภท การใช้งาน รูปแบบ และวัสดุ ราคาสมเหตุผล โทร.0914454919 หรือ Line ID : @sealwise Alpha Sintered Silicon carbide does however sacrifice the Pressure Velocity ratios due to the lack of un-reacted free carbon. In higher viscosity fluids, the fluid creates a full fluid film lubrication mode and allows either soft vs hard or hard vs hard material combination. For this reason, the materials should be evaluated against their interaction with the location and magnitude of pressure acting on the faces. The face materials will contact each other and good tribological pairings prevent the seal faces from causing significant damage to each other. The pressure from the plug will seal … Tungsten carbide also can be re-lapped and polished to be re-used. These lapped faces run against each other, one rotating with the shaft and the other stationary with the equipment housing. Your Mechanical Seal The illustrations below demonstrate the correct procedure of measuring and properly identifying a mechanical seal that is best suited to the application of your needs. var plc443273 = window.plc443273 || 0; High operating pressures can push the limits of the face material’s mechanical properties. A mechanical seal has 4 main sealing points (indicated by orange circles as per Figure 3): I. Carbon is an ideal seal face material for the range of conditions within a mechanical sealing system, and is widely used. Turbomachinery Blog features postings from experts in all areas of turbomachinery, such as: gas turbines, machine diagnostics, materials, repairs, and aftermarket parts, and encourages users to participate, with reader engagement and interaction as its primary purpose. Another group of seal faces would be those of coated seal faces. The seals in these figures were run under the same operating conditions but only the left hand face material was changed. Even the best material combinations can still experience unwanted performance such as accelerated wear or high leakage. GFPTFE - Say that one ten times.... Glass Filled PTFE (most people just say Teflon (R)). Pressure Limits The seal ring and mating ring are sometimes referred to as the primary sealing surfaces. • Although the faces can be manufactured from a myriad of different materials, one is typically carbon, while the other is usually a hard material. The first question to ask when trying to choose the combination is: Do the faces need to have self-lubricating properties? Ceramic - Generally a 99.5% aluminum oxide offering excellent wear characteristics due to it's hardness. Identifier – EN 12756 Description; Spring materials: G: 1.4571 CrNiMo steel: M: Hastelloy C-4 Nickel-base alloy: Construction materials: D: C*steel: E: Cr-steel The old adage "pay me now or pay me later" applies to seals. (This gives rise to the alternative name Radial Face Seal, Pump Seals or Packings.) However, certain soft materials, like carbon, are not recommended in higher viscous fluids due to high viscous shearing forces between seal faces which can cause a localized binder failure known as blistering. Compare and identify seal Head Type from the Head Type list. © 2018 Mechanicalseals.net. A plug is a simple example of a mechanical seal. var AdButler = AdButler || {}; AdButler.ads = AdButler.ads || []; These high deformations should be minimized to avoid accelerated or heavy wear and higher than normal leakage. Your input is appreciated. A plug consists of a sponge-like material such as cork or rubber. The BT-A2 features all carbon or high quality resin impregna-ted carbon, aluminium oxide 96 %, is stationary and the rubber bel-lows are glued on collar. Low cost, ability to conform to the opposing face, self-lubrication properties, and low coefficient of friction are just a few of the reasons for carbon’s popularity as a seal face material. Carbon Graphite is a self-lubricating mechanical seal face material, generally used as a mechanical seal rotating face. Particles that are harder than the face material have a high potential to damage the face. This is known as the primary seal. The first step in the seal se l ection process is identifying the exact liquid to be handled. It is suitable for Sewatec, Sewabloc and Amarex KRT pumps with the following shaft diameters in the mechanical seal area: 022/025, 033/033 and 033/055. We have found the coating will always eventually wear and once it has will need to be completely recoated. The more common end- or rotating-face mechanical seal designs feature mating faces as the primary sealing elements. Mechanical seals can operate for many years without issue, as long as they've been properly selected for their application. Trends in Applying Face Material When inserted into a hole it will press against the hole’s exteriors which creates the mechanical pressure. equipment. The majority of mechanical seals are applied in applications where the product enters and exits the mechanical seal faces as a liquid. If soft vs. hard faces are required in these applications, then special considerations should be employed such as selecting seal designs with the process fluid at the outer diameter (OD) of the seal face and applying API Plan 62 external quench at the ID to flush away the particles on the atmospheric side of the seal. (Fig.1) The main components of a mechanical seal are the seal rings on which a mechanical force is acting, generated by springs or The search to advance these limitations without sacrificing the excellent tribological properties has been a major driving force in the evaluation and advancement in carbon materials. Each of these have described below in detail. We focus on eliminating the common issues found in original types through improved design, technology and material compatibility. Material code designation example Preferred materials 3) DIN 24960, June 1980 1) EN 12756, Dec. 2000, return to DIN 24960, June 1992 4) Burgmann Design Manual 2) Shortway acc. These show the resin carbon, with the lowest thermal conductivity, kept the heat trapped at the faces causing a higher temperature than the other two faces. Mechanical Seals come in a wide range of designs however the most important factor when determining how long a seal is going to last, is deciding on the right seal face materials. However, even with these desirable characteristics, there are limits for this material such as a relatively low modulus of elasticity, poor thermal conductivity and low material hardness of the face. Gasket (2). Chemical Mechanical Seal. Gives the chemical resistance of PTFE however glass must be added to give the face hardness and to prevent cold flow issues associated with PTFE. Learn about more differences and uses here. If an external quench is not available, then the application should be evaluated with a hard vs. hard face combination, potentially using special features on the faces. AI, visualisation to help reduce Covid risk in facilities, What API 682 says on mechanical seal selection, View past issues of Turbomachinery International Magazine, Subscribe (both print and online options available), Register for webcasts (live and on-demand). © 2019 MultiMedia Pharma Sciences LLC | All Rights Reserved. The other face will be a harder material (or have a different lapped surface) providing dissimilar materials (or dissimilar surface) making contact and allowing one to be a sacrificial. Let us know how we can serve you better, what you would like to see, or how you feel we can improve our site. A lower conductivity material will have a higher temperature gradient and distort the seal face in undesirable ways. It has superior wear characteristics with a broad chemical resistance. The sealed fluid migrates between the flat faces and form… Its chemical name is Aluminium oxide (Al 2 O 3).It has two types, varying with purity composition of 96% and 99.9%. Head Type C. Mechanical seals Mechanical Seals. Included in this list is the selection of the materials of construction of the seal. John Crane is an American company, now a subsidiary of Smiths Group and provider of engineered products and services including mechanical seals, couplings, hydro-dynamic bearings, seal support systems, filtration systems and artificial lift. II. The three basic classifications are:  The sealed product enters and exits the sealing gap as a liquid  The sealed product enters and exits the sealing gap as a gas  The sealed product enters the sealing gap as a liquid and vaporizes to a gas before it exits. (i.e. You must consider the environment the seal will be exposed to. Rings of ceramic, carbide, carbon or composites of these materials are lapped flat in the range of less than 1 micron on an axial end face. Soft vs. hard seal face combinations are traditionally used in boundary lubricated and mixed lubrication modes that require self-lubricating properties. document.write('<'+'div id="placement_443273_'+plc443273+'">'); External temperatures from sources such as the pumped fluid, a heating/cooling jacket, or seal cooling piping plans, all influence the overall average face temperature. Mechanical seals areconstructed of a wide range of materials This means the face materials selected must have good tribological pairings and are typically a soft vs. hard face combination. if (!window.AdButler){(function(){var s = document.createElement("script"); s.async = true; s.type = "text/javascript";s.src = 'https://servedbyadbutler.com/app.js';var n = document.getElementsByTagName("script")[0]; n.parentNode.insertBefore(s, n);}());} Chemical Seal is a mechanical seal which is made of ceramic. Further information: OEM Replacement Seals. Typical features applied to mechanical seal faces include hydropads, lube grooves, hydrodynamic grooves, waves, or in some cases creating specialized flat-face seal face geometry. 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. This articles describes some of the commonly used mechanical seal types like Cartridge type mechanical seals, Balanced type, Unbalanced type, Conventional, Pusher, and Non-Pusher type of mechanical seals. One must identify the application data (or operating conditions) to properly select the type of seal and materials of construction to ensure maximum performance from the seal over its lifetime. Abrasive environments require seal faces that will hold up to the wear and tear of abrasive environments. They have been sold by various trade names by the major mechanical seal companies but in our opinion are not worth the money. The initial cost of Gland (Pump) Packing is low when compared to the costs associated with mechanical seal. Why use a Mechanical Seal? The high pressure may require face geometry changes to the face wear nose to reduce the potential for high contact loads. The mechanical seal itself is the interface between the static and rotary portions of the seal. it is an inexpensive seal face and ideal for fresh water applications. We also manufacture an extensive range of OEM replacement Mechanical Seals. Thermal conductivity of the face material is an indication of how the face will effectively dissipate heat generated from the sealing gap to the rest of the face. Different Temperature Effects Fluid loss will increase as gland packing material begins to wear down and may impair regular lubrication or reduce ease-of-replacement. Ideal for high pressure applications due to a high modulus of elasticity which helps prevent face distortion. In dirty or contaminated applications, the properties and concentrations of suspended solids or crystallization particles becomes critical. In Chemical applications however, Alpha Sintered Silicon Carbide may be recommended. Mechanical seals are more durable than their predecessors and use multiple sealing points to nearly eliminate any leakage issues. 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. The old adage "pay me now or pay me later" applies to seals. var abkw = window.abkw || ''; • The mechanical seal faces are obviously the most critical sealing point of a mechanical seal assembly. Static air pressure test to 100 % production. Table 2 compares the application advantages of carbon grades versus hard face options. In general, low viscosity services are more likely to operate in boundary or mixed lubrication environments and thus are most appropriately sealed with a soft vs hard face combination. Most packings must leak an average of 6 drops per minute (with the exception of flexible graphite), to lubricate the shaft. Fluids that crystallize or salt as they migrate across the faces or salt on the atmospheric side may also cause significant damage to a soft face. Bronze D. Brass A. Unlike an O-Ring seal, the hydraulic diameter of a bellows seal is not a fixed geometric value. Internal heat sources such as friction and turbulence can cause locally higher temperatures acting on a portion of the seal faces. Ceramic cannot however handle the thermal shocks that Ni-resist or 17-4 seats can. Once the initial seal combination has been chosen using the viscosity, a few other considerations have to be evaluated to ensure the face materials will perform as expected. The first area of consideration when choosing seal face materials is the product phase (liquid or gas) as it enters and exits the mechanical seal sealing gap. Bi-directional and balanced, the seal is very installer-friendly. Thermal Considerations The properties of the liquid are important as they have a large impact on determining the lubrication mode of operation. Face Features American Seal & Packing stocks both packing and mechanical seals, and can help you decide what is best in your application. A pusher mechanical seal utilizes a dynamic secondary seal or o-ring that is responsible for sealing the fluid path between the pump shaft and the inside diameter of the rotating seal face. It is chemically inert and can be applied to nearly any product. mechanical seal and is defined as In practice k values are selected between 0.65 and 1.2. Mechanical Seals - Face Materials. In recent history, whenever carbon is compatible with the product fluid it has been the general practice to select a hard face material such as silicon carbide or tungsten carbide versus a compliant soft material usually a grade of blister-resistant carbon. The most common is reaction-bonded silicon carbide. Ni-resist - Is a form of Stainless steel which has had nickel added to it to lower the friction generated by the rotating face. The primary sealing surfaces are the heart of the end-face mechanical seal. to DIN ISO 1629, Nov. 2004 Mechanical Seals (DM) Face materials (Item 1 / 2) Secondary seal components (Item 3) KOMA4) 13/4 13/3 11.98 2.88 Current material code The wide range of different materials available for mechanical seal faces makes choosing the right face combination seem difficult. Seal face materials in the boundary lubricated or mixed lubricated mode may experience high wear rates if surface velocities are high. There are various types and arrangement of the mechanical seals being used for the centrifugal pumps. Alox (Aluminum Oxide Ceramic), Tungsten Carbide, Silicon Carbide, etc.) It is even more intimidating knowing that the wrong combination of materials may lead to premature seal failure, which in turn leads to significant costs due to replacement of the seal, downtime of the pump, and potential damage caused to the equipment. Hard vs. hard faces are typically applied in full fluid film applications that do not necessarily need good tribological properties since the face materials should not come into contact. When hard particles are present, face materials with a higher hardness must be selected for both seal faces. Even small temperature increases can have a large, indirect influence on the face material by changing the aggressiveness of corrosive fluids, affecting the phase change of the fluid, or decreasing the fluid viscosity.The rotational velocity of the seal face also impacts the choice of seal face materials. III. They will also shatter like a plate if dropped on concrete. AdButler.ads.push({handler: function(opt){ AdButler.register(166254, 443273, [620,150], 'placement_443273_'+opt.place, opt); }, opt: { place: plc443273++, keywords: abkw, domain: 'servedbyadbutler.com', click:'CLICK_MACRO_PLACEHOLDER' }}); The wide range of different materials available for mechanical seal faces makes choosing the right face combination seem difficult. All Rights Reserved. Axial thermal gradients across a seal faces can create uneven thermal expansion in the face leading to detrimental thermal coning. It makes little sense to save money on the seal only to have to spend more money to replace the seal later. Bronze E. Monel E. EPR C. Carbon E. Monel G. Cast Iron F. Stainless Steel N. Neoprene M. Phenolic F. Stainless Steel J. Moreover, the wrong combination of sealing materials may cause premature seal failure and worse losts. The most common types of seal faces are: Carbon, Ceramic, Ni-resist, 17-4, Silicon Carbide, Tungsten Carbide, GFPTFE (glass filled PTFE.... often called Teflon (R)). It is also influenced by Sealing material is an important factor that affects the service time of a mechanical seal. The use of these features can also allow application of materials that may not traditionally be used in some services; like a hard vs. hard combination in a flashing hydrocarbon application. Silicon Carbide - Is a bluish-black material created by fusing silica and coke. It is in the same family as Ceramic (due to the Silica), but has much better lubrication qualities and is harder. They are typically categorized as either a soft vs. hard or a hard vs. hard combination. These sources can lead to unwanted thermal growth or retraction and potential destruction of the impregnation or binding material. Mechanical Seals come in a wide range of designs however the most important factor when determining how long a seal is going to last, is deciding on the right seal face materials. OEM Replacement Mechanical Seals. Each mechanical seal requires at least two opposing seal faces. 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. Grundfos CRN SHAFT Seal Kit Pump Cartridge Mechanical Seal CR32 45 64 90 Grundfos Sarlin Pump 62kW Pump Model S.2.100.200-550.66M.D.338.GND Upper & Lower Mech Seals 65 mm Grundfos CR 45, 64, 90 Pump Cartridge Mechanical Seal – Fits 32 45 64 90 Fluid Viscosity Seal faces are exposed to a wide variety of process fluids. The seal between the rotating (3) and stationary faces (1). You must consider the environment the seal will be exposed to. Spread throughout the world, this type of mechanical seal has reached an unsurpassed quali-ty level. Once the properties of the fluid acting between the faces is understood, the lubrication profile can be evaluated using tools such as FEA or by looking at physical evidence from a previously run set of seal faces in the exact application or in similar services. Some of these process fluids are aggressive and will chemically react with individual components of the material such as the base material, the binder, or filler material. The coatings are "plasma coatings" and are generally a form or silicon or tungsten carbide sprayed onto a stainless steel seal head. Head Type B. Head Type A. Material Chemical Compatibility The most common consideration for face selection is the viscosity of the fluid at the working temperature. In particular, these types of applications depend on the fluid viscosity to choose the right materials. We have gained expertise in manufacturing and exporting supreme quality Mechanical Seal that are specifically designed for our esteem clients.The offered range is manufactured using material which is sourced from authentic and reliable sources. Our standard grade of carbon used is CNFJ. The softer mechanical seal face usually has the smaller mating surface and is commonly called the "wear nose" of the mechanical Seal. The seal between the rotating member and shaft or shaft sleeve (4). The inherent self-lubricating properties of certain materials often come paired with a lower modulus of elasticity and the potential for significant pressure deformations. In contrast, if a Silicon Carbide or Tungsten Carbide seal face is worn, it can generally be re-lapped and polished , bringing it back to "like new" condition and allowing a second, third or even fourth use of the same seal head. Low velocities (less than 350 RPM), when combined with lower pressures, may allow self-lubricating seal face materials to operate in a fully boundary lubricated mode of operation for a significant period of time. Higher rotational velocities also increase friction-generated heat between the seal faces and create a larger thermal gradient that causes uneven wear or higher leakage. For severe applications, Antimony Filled Carbon can be applied to assist with any mechanical seal face issues. It is very hard like silicon carbide however it is very heavy to the touch, making it easy to distinguish from silicon carbide. Tungsten Carbide - A very versatile seal face like Silicon Carbide. This article contains excerpts from the paper, “The Evolution and Application of Mechanical Seal Face Materials,” presented by William Dietzel and Jack Vasko of Flowserve in the 2015 Turbomachinery Pump Symposium. This is why pump packing is the primary source of packing for fire pumps and other applications that can’t risk catastrophic failure. Stationary mechanical seal in inch dimensions. Reducing the wear rate may require changing the seal geometry and using material with self-lubricating properties. Mechanical seal face materials react differently to the various external and internal temperatures acting on the seal faces. With a lower k value, the safety against thermal overload will increase, but the mechanical seal may also lift off more easily. In these cases seal vendors have continued to use these combinations, but apply special considerations to meet the seal’s performance expectations. On the other hand if you are pumping very clean fluid that has a lubricating quality such as machine oil or Ethylene Glycol, save your money for better quality bearings. The double mechanical seal in tandem arrangement can be installed as one unit. In the same way a pencil transfers graphite to a piece of paper, mechanical carbon can transfer material to the mating face—the level of that … In the two classifications where the product exits as a gas, the lubrication mode is going to be boundary lubricated or mixed lubricated. MECHANICAL SEAL MATERIAL CODES Elastomers Washers Metal Parts Seats Springs B. Buna A. Turbomachinery Magazine brings you the latest and most comprehensive news and perspective in the industry. Either grade of SIC can usually be re-lapped and polished to be reused. A common material combination for the primary sealing surfaces is a hard material, such as silicon carbide, ceramic or tungsten carbide and a softer material, such as carbon. Whereas mechanical seal failure can necessitate the shutdown of the pump. Users must consider the working environment the seals are used and choose the right seal face materials. The silicon carbide, with the highest conductivity, transferred the heat from the sealing interface, keeping the wear nose temperature the lowest.

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