This is why pump packing is the primary source of packing for fire pumps and other applications that can’t risk catastrophic failure. 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. Fluid loss will increase as gland packing material begins to wear down and may impair regular lubrication or reduce ease-of-replacement. Either grade of SIC can usually be re-lapped and polished to be reused. 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. 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)). The properties of the liquid are important as they have a large impact on determining the lubrication mode of operation. For severe applications, Antimony Filled Carbon can be applied to assist with any mechanical seal face issues. 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. 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. 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. You must consider the environment the seal will be exposed to. 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. When hard particles are present, face materials with a higher hardness must be selected for both seal 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. (Fig.1) The main components of a mechanical seal are the seal rings on which a mechanical force is acting, generated by springs or Alpha Sintered Silicon carbide does however sacrifice the Pressure Velocity ratios due to the lack of un-reacted free carbon. In the two classifications where the product exits as a gas, the lubrication mode is going to be boundary lubricated or mixed lubricated. 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 seal ring and mating ring are sometimes referred to as the primary sealing surfaces. 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 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. var AdButler = AdButler || {}; AdButler.ads = AdButler.ads || []; Static air pressure test to 100 % production. The initial cost of Gland (Pump) Packing is low when compared to the costs associated with mechanical seal. You must consider the environment the seal will be exposed to. Compare and identify seal Head Type from the Head Type list. Mechanical seals are more durable than their predecessors and use multiple sealing points to nearly eliminate any leakage issues. Users must consider the working environment the seals are used and choose the right seal face materials. Trends in Applying Face Material The seal between the rotating member and shaft or shaft sleeve (4). Another group of seal faces would be those of coated seal faces. Its chemical name is Aluminium oxide (Al 2 O 3).It has two types, varying with purity composition of 96% and 99.9%. © 2019 MultiMedia Pharma Sciences LLC | All Rights Reserved. A mechanical seal has 4 main sealing points (indicated by orange circles as per Figure 3): I. Mechanical Seal. The mechanical seal itself is the interface between the static and rotary portions of the seal. Why use a Mechanical Seal? 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. 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. 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. Each mechanical seal requires at least two opposing seal faces. Particles that are harder than the face material have a high potential to damage the face. • The mechanical seal faces are obviously the most critical sealing point of a mechanical seal assembly. With a lower k value, the safety against thermal overload will increase, but the mechanical seal may also lift off more easily. var plc443273 = window.plc443273 || 0; It has superior wear characteristics with a broad chemical resistance. 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. Ceramic - Generally a 99.5% aluminum oxide offering excellent wear characteristics due to it's hardness. Ni-resist - Is a form of Stainless steel which has had nickel added to it to lower the friction generated by the rotating face. 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. The softer mechanical seal face usually has the smaller mating surface and is commonly called the "wear nose" of the mechanical Seal. 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. We focus on eliminating the common issues found in original types through improved design, technology and material compatibility. Learn about more differences and uses here. Ideal for high pressure applications due to a high modulus of elasticity which helps prevent face distortion. 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 … They will also shatter like a plate if dropped on concrete. Table 2 compares the application advantages of carbon grades versus hard face options. Tungsten Carbide - A very versatile seal face like Silicon Carbide. There are various types and arrangement of the mechanical seals being used for the centrifugal pumps. The coatings are "plasma coatings" and are generally a form or silicon or tungsten carbide sprayed onto a stainless steel seal head. Bi-directional and balanced, the seal is very installer-friendly. 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. (i.e. The wide range of different materials available for mechanical seal faces makes choosing the right face combination seem difficult. Abrasive environments require seal faces that will hold up to the wear and tear of abrasive environments. However the longer you keep your pump in service, the more cost effective a mechanical seal can be. In Chemical applications however, Alpha Sintered Silicon Carbide may be recommended. 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. The old adage "pay me now or pay me later" applies to seals. Mechanical seals can operate for many years without issue, as long as they've been properly selected for their application. 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. Spread throughout the world, this type of mechanical seal has reached an unsurpassed quali-ty level. A plug is a simple example of a mechanical seal. In particular, these types of applications depend on the fluid viscosity to choose the right materials. The seals in these figures were run under the same operating conditions but only the left hand face material was changed. Alox (Aluminum Oxide Ceramic), Tungsten Carbide, Silicon Carbide, etc.) Included in this list is the selection of the materials of construction of the seal. 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. The high pressure may require face geometry changes to the face wear nose to reduce the potential for high contact loads. 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. แมคคานิคอลซีล จัดจำหน่ายโดย ซีลไวส์ มี แมคคานิคอลซีล ทุกแบบ ทุกชนิด ทุกประเภท การใช้งาน รูปแบบ และวัสดุ ราคาสมเหตุผล โทร.0914454919 หรือ Line ID : @sealwise 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. Head Type C. 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. Carbon is an ideal seal face material for the range of conditions within a mechanical sealing system, and is widely used. For this reason, the materials should be evaluated against their interaction with the location and magnitude of pressure acting on the faces. A plug consists of a sponge-like material such as cork or rubber. The most common is reaction-bonded silicon carbide. Carbon Graphite is a self-lubricating mechanical seal face material, generally used as a mechanical seal rotating face. These sources can lead to unwanted thermal growth or retraction and potential destruction of the impregnation or binding material. Our standard grade of carbon used is CNFJ. 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 seal face materials react differently to the various external and internal temperatures acting on the seal faces. When inserted into a hole it will press against the hole’s exteriors which creates the mechanical pressure. Fluid Viscosity The primary sealing surfaces are the heart of the end-face mechanical seal. Mechanical seals areconstructed of a wide range of materials 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. Head Type B. Material Chemical Compatibility The seal between the rotating (3) and stationary faces (1). The inherent self-lubricating properties of certain materials often come paired with a lower modulus of elasticity and the potential for significant pressure deformations. 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. GFPTFE - Say that one ten times.... Glass Filled PTFE (most people just say Teflon (R)). Ceramic cannot however handle the thermal shocks that Ni-resist or 17-4 seats can. Further information: OEM Replacement Seals. Reducing the wear rate may require changing the seal geometry and using material with self-lubricating properties. Stationary mechanical seal in inch dimensions. We also manufacture an extensive range of OEM replacement Mechanical Seals. 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. Soft vs. hard seal face combinations are traditionally used in boundary lubricated and mixed lubrication modes that require self-lubricating properties. Silicon Carbide - Is a bluish-black material created by fusing silica and coke. Thermal Considerations 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. 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. They have been sold by various trade names by the major mechanical seal companies but in our opinion are not worth the money. 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. Mechanical seals Mechanical Seals. MECHANICAL SEAL MATERIAL CODES Elastomers Washers Metal Parts Seats Springs B. Buna A. The first question to ask when trying to choose the combination is: Do the faces need to have self-lubricating properties? The double mechanical seal in tandem arrangement can be installed as one unit. document.write('<'+'div id="placement_443273_'+plc443273+'">'); 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 It is in the same family as Ceramic (due to the Silica), but has much better lubrication qualities and is harder. 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. 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. 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. The sealed fluid migrates between the flat faces and form… 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. 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 first step in the seal se l ection process is identifying the exact liquid to be handled. We have found the coating will always eventually wear and once it has will need to be completely recoated. Seal face materials in the boundary lubricated or mixed lubricated mode may experience high wear rates if surface velocities are high.