Ideally, a strong relationship with the seal manufacturer. He continues to support training internally, at end users, and at major symposiums and conferences. Should the issue be particularly challenging or if the problem. Confirm that the pump is operating in its equipment reliability operating envelope eroe. Check out our ebook, ways to kill a mechanical seal, and find out whats causing mechanical seal failure and how you can prevent it. Guidelines for predictive maintenance of mechanical seals. Seal chamber and stuffing box both refer to a chamber, either integral with or separate from the pump case housing that forms the region between the shaft and casing where sealing media are installed. These seals virtually eliminate leakage of the fluid or gas being handled in pumps or mixers. Flowserve will not accept any warranty claims for failures as a result of inadequate storage.
Common conditions requiring pump troubleshooting expertise are cavitation, hydraulic imbalance, undersized shafts, and mechanical seal failure. Other times, failure is a result of poor selection or installation errors. Failure of outboard mechanical seal assembly failure of inboard mechanical seal assembly external seal characteristics leak internal seal. Allowing the pump to run dry allowing your pump to run dry can be very damaging to a mechanical seal. What is a double seal and when to use one double seals. Analysis of a mechanical seal failure in maintenance organizations where time and cost of repair are crucial elements, it is of paramount importance for a reliability engineer to determine swiftly and accurately the failure modes and root causes underlying a particular issue to avoid further machinery breakdowns. Aug 01, 2018 hello friends iss video me mechanical seal ko centrifugal pump me kaise install karte hai btaaya gya hai. Mechanical seal technology and selection eagleburgmann.
Improperly starting the pump can cause the motor to trip and the shaft to twist causing orbital movement, resulting in internal parts contact, seal failure, and shortened bearing life. How to respond to mechanical seal leakage in a centrifugal. This is essential when pumping or mixing a dangerous or toxic substance. Mechanical seal principles manual chapter 7 introduction provide a systematic approach to successful root cause failure analysis relate symptoms to causes and failure modes improve sealing system and mtbf chesterton. The rubber drive ring was forced up into the seal the seal came apart upon final installation. Unfortunately, in many plants over half the pumps may still use stuffing boxes. John crane offers onsite troubleshooting to identify the root cause of failures and recommend repairs, refurbishments or upgrades. He is a member of the api 682 task force on mechanical seals and the asme b73 committee for. Or, in the case of excessive vibration or instability, the resolution can be difficult to address without the assistance of a trained expert. Torishimas mechanical seals 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. Flowserve mechanical seals from the gaspac product line should use gaspac guideline no. A mechanical seal pump could potentially save you a lot of annual costs. Sep 17, 2014 because mechanical shaft seal failures are the number one cause of pump downtime, we decided to dedicate this column to mechanical seal basics. Dec 17, 2011 an effective pump troubleshooting tool will always begin with the question when did this start.
We will repair your existing seal or quote you a replacement seal. Jan 03, 2015 for optimum mechanical seal mtbfs, execute the following mechanical seal monitoring best practices. The wrong lubrication was used as indicated by the transfer of carbon to the mating ring. Among this divisions more recent contributions to the associations educational mission is the. Failure analysis and troubleshooting mechanical seals and systems. Check system and application for operating condition. Sometimes operating conditions change to become quite different from the specific conditions for which the seal was intended. Seal selection can be based on the fluids specific gravity and the maximum allowable voc emission levels. Mechanical seal leak problem marzzia666 mechanical op 30 jul 08. The seal ring which rotates with the shaft is called the rotary ring. Failure analysis and troubleshooting mechanical seals and.
Mechanical seals are used in industrial pumps, compressors, and other applications to provide a leakproof seal between component parts. Mechanical seal education tutorials mechanical seal. Troubleshooting mechanical problems for bearings, mechanical. These are questions posed to mechanical seal manufacturers every day. When the sealing is achieved by means of a mechanical seal, the chamber is commonly referred to as a seal chamber. 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. Refrigeration troubleshooting guide cornell pump company efficient by design. Apart from ensuring the accurate placing of the seal on the pump shaft there is little to be done to compensate for such movement. In the drawing, it is instructed that the drain plug should be removed before operation, unfortunately the plug was not removed and the equipment was running for 3 months in this condition. With a lower k value, the safety against thermal overload will increase, but the mechanical seal may also lift off more easily.
Figure 1 shows a basic overview of what a 53b seal flush plan looks like. Flowserve mechanical seal and seal support system storage. Seal users have realized that the answers to these questions are complex and often lead to even more difficult questions. Eliminate frequent starts and stops of rotating equipment that contain mechanical seals to help prevent blistering. It is a pressurized flush plan that gets used with a dual seal i. Here are 6 of the most common reasons mechanical seals can fail.
Checklist of problems vvith centrifugal pumps and their causes. Double seals provide a level of safetyzero emissions compliance not possible with single 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. 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. By changing from stuffing boxes to seal chambers, the user has a greater selection of seals options, benefits of improved seal cooling, and potential for greater seal reliability. Assembly video mechanical seal installation youtube. Piping plans help keep mechanical seals running cool and clean, promote safe handling of dangerous fluids, and extend the operational availability of rotating equipment.
Seal was started on shaft, then removed and reinstalled. Of course, the mechanical seal should be correctly and most optimally designed for the particular application at hand. Look for other types of damage to help troubleshoot this problem. Skipping initial startup procedures and installation errors are a big factor when it comes to mechanical seal failure.
Under the right conditions, mechanical seals can experience thermal shock and shatter within 30 seconds. Improper cooling and circulation on the seal face will also increase your chance for blistering. Because mechanical shaft seal failures are the number one cause of pump downtime, we decided to dedicate this column to mechanical seal basics. Mechanical seal working installation and parts explained. Loud blow is heard each time pump is started or stopped 20. An effective pump troubleshooting tool will always begin with the question when did this start. This document is intended to clarify what to expect on mechanical seals found in colfax products. Double or dual mechanical seals are designed to ensure maximum sealing safety. A mechanical seal, figure 1, consists of a stationary member seat. There are many different designs of a mechanical seal to meet specific applications. Unlike an oring seal, the hydraulic diameter of a bellows seal is not a fixed geometric value. Dirt or contamination in between the mechanical seals. The process leakage from the inner seal mixes with the buffer liquid and is separated and safely removed within the buffer liquid circuit or the barrier liquid or gas lubricates the seal faces and prevents process liquid leakage.
Also called the heart of the curve, it assures maximum centrifugal pump mtbf by avoiding all operating areas of hydraulic disturbances. The faces of the outboard have some scratches according to vendor inspection report. Check for a plugged flush line orifice by taking temperature. Given the general geometry of a mechanical seal, anywhere that theres a gasket or an oring, there ensues a potential leak point. I would like to ask anyone who has any experience with flowserve plan1153b seal.
Slowly close delivery valve and shut down driving unit in accordance with manufacturers instructions. Representing all of the major mechanical seal manufacturers. When the sealing is achieved by means of a mechanical seal, the chamber is. When the seal heats up, the oil from the viscous fluid is rapidly driven out from the pores in the seal face. Faces openingflashing operating near vapor point vibration cavitation equipment operation products hardening and settingup. To install a seal, the pump would have to be taken offline and disassembled. In many cases it is the user that can best answer their own questions. Introduction to failures failure of the mechanical shaft seal is the most common cause of pump downtime. Mechanical seal leak problem mechanical seal engineering. Field troubleshooting common mechanical seal piping plans michael huebner principal engineer flowserve corporation pasadena, tx usa ronald hurst manager, application engineering flowserve corporation pasadena, tx usa michael huebner is a principal engineer at flowserve corporation in pasadena, tx. Years ago, most pump shafts were sealed using rings of soft packing, compressed by a packing gland, but this type of shaft seal required a fair amount of leakage just to lubricate the packing and keep.
Proper troubleshooting not only helps correct underlying issues, but it can also contribute to improved output, increased uptime and greater compliance with environmental and safety standards. Analysis of a mechanical seal failure reliabilityweb. Sometimes, the cause of a power transmission coupling, mechanical seal or hydrodynamic bearing failure can be unclear. The shaft seal is exposed to widely varying operating conditions. Weibull plot showing failures after the mechanical seal upgrade. An eroded, worn, or fretted dynamic oring or gasket as the mechanical seal moves. Seal is being mechanically loaded by a metallic or elastomeric retaining device. Centrifugal pump problems 5 overview of pump problems typically found on centrifugal pumps.
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