To install a seal, the pump would have to be taken offline and disassembled. With a lower k value, the safety against thermal overload will increase, but the mechanical seal may also lift off more easily. Mechanical seal working installation and parts explained. Should the issue be particularly challenging or if the problem. Ideally, a strong relationship with the seal manufacturer. The faces of the outboard have some scratches according to vendor inspection report. The shaft seal is exposed to widely varying operating conditions. He is a member of the api 682 task force on mechanical seals and the asme b73 committee for. John crane offers onsite troubleshooting to identify the root cause of failures and recommend repairs, refurbishments or upgrades. Given the general geometry of a mechanical seal, anywhere that theres a gasket or an oring, there ensues a potential leak point. Analysis of a mechanical seal failure reliabilityweb. These are questions posed to mechanical seal manufacturers every day. Figure 1 shows a basic overview of what a 53b seal flush plan looks like.
What is a double seal and when to use one double seals. The seal ring which rotates with the shaft is called the rotary ring. Unlike an oring seal, the hydraulic diameter of a bellows seal is not a fixed geometric value. Seal users have realized that the answers to these questions are complex and often lead to even more difficult questions.
Check out our ebook, ways to kill a mechanical seal, and find out whats causing mechanical seal failure and how you can prevent it. Faces openingflashing operating near vapor point vibration cavitation equipment operation products hardening and settingup. 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. Flowserve will not accept any warranty claims for failures as a result of inadequate storage. 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.
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. 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. Failure analysis and troubleshooting mechanical seals and. This is essential when pumping or mixing a dangerous or toxic substance.
Unfortunately, in many plants over half the pumps may still use stuffing boxes. I would like to ask anyone who has any experience with flowserve plan1153b seal. Among this divisions more recent contributions to the associations educational mission is the. 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. How to respond to mechanical seal leakage in a centrifugal. Mechanical seal technology and selection eagleburgmann. In many cases it is the user that can best answer their own questions.
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. Loud blow is heard each time pump is started or stopped 20. He continues to support training internally, at end users, and at major symposiums and conferences. Failure of outboard mechanical seal assembly failure of inboard mechanical seal assembly external seal characteristics leak internal seal. Flowserve mechanical seal and seal support system storage. Seal selection can be based on the fluids specific gravity and the maximum allowable voc emission levels. 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. Eliminate frequent starts and stops of rotating equipment that contain mechanical seals to help prevent blistering. Common conditions requiring pump troubleshooting expertise are cavitation, hydraulic imbalance, undersized shafts, and mechanical seal failure. Double or dual mechanical seals are designed to ensure maximum sealing safety. Sometimes operating conditions change to become quite different from the specific conditions for which the seal was intended. Seal was started on shaft, then removed and reinstalled. Confirm that the pump is operating in its equipment reliability operating envelope eroe.
The rubber drive ring was forced up into the seal the seal came apart upon final installation. There are many different designs of a mechanical seal to meet specific applications. Jan 03, 2015 for optimum mechanical seal mtbfs, execute the following mechanical seal monitoring best practices. Troubleshooting mechanical problems for bearings, mechanical. Mechanical seals are used in industrial pumps, compressors, and other applications to provide a leakproof seal between component parts. Slowly close delivery valve and shut down driving unit in accordance with manufacturers instructions. When the seal heats up, the oil from the viscous fluid is rapidly driven out from the pores in the seal face. Representing all of the major mechanical seal manufacturers. 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. We will repair your existing seal or quote you a replacement seal. Seal is being mechanically loaded by a metallic or elastomeric retaining device. Allowing the pump to run dry allowing your pump to run dry can be very damaging to a mechanical seal. 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. Flowserve mechanical seals from the gaspac product line should use gaspac guideline no.
An effective pump troubleshooting tool will always begin with the question when did this start. Weibull plot showing failures after the mechanical seal upgrade. Double seals provide a level of safetyzero emissions compliance not possible with single seals. Because mechanical shaft seal failures are the number one cause of pump downtime, we decided to dedicate this column to mechanical seal basics. Of course, the mechanical seal should be correctly and most optimally designed for the particular application at hand.
Check system and application for operating condition. An eroded, worn, or fretted dynamic oring or gasket as the mechanical seal moves. Mechanical seal education tutorials mechanical seal. 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.
Guidelines for predictive maintenance of mechanical seals. 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. Other times, failure is a result of poor selection or installation errors. Mechanical seal leak problem marzzia666 mechanical op 30 jul 08. Improper cooling and circulation on the seal face will also increase your chance for blistering. 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. This document is intended to clarify what to expect on mechanical seals found in colfax products. Dirt or contamination in between the mechanical seals. Refrigeration troubleshooting guide cornell pump company efficient by design.
Here are 6 of the most common reasons mechanical seals can fail. It is a pressurized flush plan that gets used with a dual seal i. Checklist of problems vvith centrifugal pumps and their causes. Look for other types of damage to help troubleshoot this problem. These seals virtually eliminate leakage of the fluid or gas being handled in pumps or mixers. Introduction to failures failure of the mechanical shaft seal is the most common cause of pump downtime.
Assembly video mechanical seal installation youtube. 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. 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. A mechanical seal, figure 1, consists of a stationary member seat. Under the right conditions, mechanical seals can experience thermal shock and shatter within 30 seconds. Centrifugal pump problems 5 overview of pump problems typically found on centrifugal pumps. Piping plans help keep mechanical seals running cool and clean, promote safe handling of dangerous fluids, and extend the operational availability of rotating equipment. The wrong lubrication was used as indicated by the transfer of carbon to the mating ring. Aug 01, 2018 hello friends iss video me mechanical seal ko centrifugal pump me kaise install karte hai btaaya gya hai. Dec 17, 2011 an effective pump troubleshooting tool will always begin with the question when did this start. Mechanical seal leak problem mechanical seal engineering. 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. A mechanical seal pump could potentially save you a lot of annual costs. Apart from ensuring the accurate placing of the seal on the pump shaft there is little to be done to compensate for such movement.
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