Pumps of this type are called double volute pumps they may also be referred to a. Mechanical seals consists primarily of a rotary seal face with a driving mechanism which rotates at the same speed as the pump. As the name suggests, it relies on the principal of centrifugal force. 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. Seal basics a mechanical seal is a device used to seal the interface between a rotating shaft and a stationary housing figure 1. Same casing as used for conventional centrifugal pumps.
Instead the torque is driven along the rubber bellow which fits on the shaft. Centrifugal pump problems 5 overview of pump problems typically found on centrifugal pumps. Allowing the pump to run dry allowing your pump to run dry can be very damaging to a mechanical seal. Seal flush from pump discharge and recirculation to pump suction with orifices. The seals are arranged by shaft size from smallest to largest. The mechanical seal shown in the pump photograph is a type 1 mechanical seal. Single spring mechanical seals for centrifugal pumps delmar. Centrifugal pumps can be classified based on the manner in which fluid flows through the pump. This portable document format \ pdf \ file contains bookmarks, thumbnails, and hyperlinks to help you navigate through the document.
Introduction to failures failure of the mechanical shaft seal is the most common cause of pump downtime. Positive displacement pumps allow liquid to flow into an open cavity trap the liquid in the pump transport liquid from the suction to discharge port mechanically force liquid out of the pump. Designed for space savings and easy servicing, the e80sc allows mechanical seal maintenance without disturbing the pump. This copy of the manual is a translation of the italian version and both. Select from a number of titles covering a multitude of various topics such as optimizing pumping systems, mechanical seals, wastewater treatment plant pumps, reliability of pumping equipment, variable frequency drives, power plant pumps, and pump. Centrifugal pumps can also be constructed in a manner that results in two distinct volutes, each receiving the liquid that is discharged from a 180. Their main job is to prevent the pumped product from leaking into the environment and are manufactured as single or double seals. There are various types and arrangement of the mechanical seals being used for the centrifugal pumps. Ceramic lined double mechanical seal centrifugal pump. Whether the pump is part of a brand new installation or is a replacement for an existing pump with an external seal.
Mechanical seals are devices that seal machines between rotating parts shafts and stationary parts pump housing and are an integral part to the pump. Most pump shafts today are sealed by means of mechanical seals. Centrifugal pump definition centrifugal pump can be defined as a mechanical device used to transfer liquid of various types. The two surfaces sliding together need to be lubricated and the seal. Model 3196 iframe installation, operation, and maintenance manual 5 introduction and safety introduction purpose of this manual the purpose of this manual is to provide necessary information for. Pdf a study aimed at seal selection efficiency for centrifugal pumps in the oil and gas industry is presented. Since its introduction in 1994, api 682 has become the standard that sets the global tone for the procurement and operation of seal and supply systems for centrifugal pumps in the oil and gas sector as well as in the petrochemical industry. This document is intended to clarify what to expect on mechanical seals found in colfax products.
For most pumps a decisive element for the quality of the pump during its lifetime is a good and robust shaft seal. Standard pumps catalog ne submersible pump for sewage operating temperatures to 104f cast iron wetted parts submersible for waste water applications suction and discharge nozzles offered up to 6 cast iron semiopen impellers for handling solids to 3 in diameter double mechanical seal, oil lubricated within a. The difference between single and double mechanical seals. Pdf analysis of mechanical seals for highspeed centrifugal gas. 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. Sometimes operating conditions change to become quite different from the specific conditions for which the seal was intended.
Mechanical seals are designed to handle a range of motions and conditions, but they are just one machinery component in a larger system. When sealing a centrifugal pump, the challenge is to allow a rotating shaft to. Requires leakage or it will burn will seal with invisible leakage. At utex, we refer to this type as rs1 the assembly shown in the pump is configured with a ceramic oring type stationary. A double mechanical seal installation kit is shipped complete with the olympia seal, stuffing box, barrier fluid reservoir, hoses, gaskets, bolts, studs, nuts, mounting bracket, and lubricant. How to change a seal on a single stage centrifugal pump cet. Centrifugal pumps high head straight centrifugal pumps 300 series investment cast stainless steel, cast bronze and cast iron construction with stainless steel impeller viton mechanical seal and oring with stainless steel and bronze models bunan mechanical seal and oring with cast iron models optional silicon carbide.
The rotating part is axially pressed against the stationary part. 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. The shaft seal is a sealing element which seals the rotating shaft of a centrifugal pump where it passes through the nonrotating pump casing, reducing fluidleakage to atmosphere or the entry of air from outside to a certain level, and keeps wear of the sealing faces as low as possible pumps. These seals are generally used in sewage applications and waste water pumps. M pumps process srl via dellartigianato, 120 45015 corbola ro italia tel.
These mechanical seals can be offered in tungsten carbide or silicon carbide sealing faces, depending on the type of application. Goulds 3ms1h2a4, centrifugal pump, series mcs, 3 hp, 208. By definition slurry pumps are heavy and robust version of a centrifugal pump, capable of handling tough and abrasive duties. Thus the mechanical seals are the devices that form the packing between the rotor and the stationary part of the centrifugal pumps to prevent the leakage of the fluid being pumped by the pump. Mechanical seals for pumps how mechanical seals work. Typically mechanical seals are installed on pumps and mixers. The materials of seal construction, particularly the sealing faces and elastomers.
A mechanical seal is simply a method of containing fluid within a vessel typically pumps, mixers, etc. Based on api 682, all mechanical seal shall be cartridge design. Incorrect installation and adjustment are the causes for failure. Other times, failure is a result of poor selection or installation errors. Single spring mechanical seals for centrifugal pumps consist of two very flat faces, one rotating dynamic and one stationary static, that slide against each other to form a seal.
Every centrifugal pump must accommodate a spinning shaft while mechanically maintaining fluid or gas contained in the wet end of the pump. Centrifugal pumps mechanical seals cp, cr, cz, s100, s200 and hl models pump model date built no. The seal in mechanical seal pumps is composed by a static ring and a rotating ring placed on the pump shaft which is directly coupled to the motor shaft. The working principle of centrifugal pumps involves imparting energy to the liquid by means of a centrifugal force developed by the rotation of an impeller that has several blades or vanes.
Sometimes operating conditions change to become quite different from the specific conditions for which the seal. Mechanical seals is not a seal but rather a restricting device. How to replace mechanical seals in centrifugal pumps. A mechanical seal consists of 2 principle components. Centrifugal pumps tsc manufacturing and supply, llc.
No matter how challenging or unique the application, all seals will find the perfect solution. This is commonly seen in centrifugal pumps although this challenge also exists in other equipment such as agitators, turbines, compressors, centrifuges, and blowers. Basics concepts of operation, maintenance, and troubleshooting, part i. In fact, every mechanical seal manufacturer has designed seal models specifically to fit into standardbore stuffing boxes. 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. The mechanical seals help sealing the rotating part of the shaft against the stationary part of the pump housing. On difficult applications the will groove and wear shafts and sleeves. This article will explain what a mechanical seal is and the key design features that make them work. Slurry pump name by duty the term slurry pump, as stated, covers various types of heavyduty centrifugal pumps. We carry mechanical pump seals and standard singlespring pump seals as well as cartridge pump seals for you centrifugal pumps and progressive cavity pumps. Goulds 3ms1h2a4, centrifugal pump, series mcs, 3 hp, 208230460 volts, 3 phase, 3500 rpm, 112 npt discharge, stainless steel, viton mechanical seal. This articles describes some of the commonly used mechanical seal types like cartridge type mechanical seals, balanced type, unbalanced type, conventional, pusher, and nonpusher type of mechanical seals. This begs for a better understanding of this seal type and its application.
Checklist of problems vvith centrifugal pumps and their causes. Mechanical seals the shaft seals used in rotating machinery such as pumps, hydraulic. Since our subject is dealing with pumps, lets first explore a basic understanding of the need to seal a process liquid in a centrifugal pump. Mechanical seals for pumps goulds, durco, and more. The manufacturer listings are alphabetical, refer to pages 7. Mechanical seals can be applied into these stuffing boxes. Cps ceramic lined double mechanical seal centrifugal pump is engineered to meet the most stringent quality standards and ensure reliability and utmost safety in production operations. Single seals made up of two flat surfaces that slide against each other and are pressed together by a spring. Understanding the basics of mechanical seals and how they may be adapted for different application requirements is critical for choosing the best seal for the job and ensuring optimal system reliability. A mechanical seal is simply a method of containing fluid within a vessel typically pumps. Centrifugal pumps develop pressure by increasing the velocity of the liquid liquid is literally flung out of the cutwater. Mechanical seals explained the basics mechanical seals are leakage control devices, which are found on rotating equipment such as pumps and mixers to prevent the leakage of liquids and gases from escaping into the environment. Mechanical sealcentrifugal pumpby rajul gupta pump.
Figure 1 shows a typical centrifugal pump, which highlights its constituent parts, including the mechanical seal. On difficult applications the leakage ratio between seals and. After nearly six years of intensive work, the american petroleum institute api 682 mechanical seal standard is soon to be adopted. Jul 20, 2012 procedure to change a seal on a single stage centrifugal pump c. Mechanical seals hvac we provide quality, reliable sealing solutions for cooling towers, hot and cold water circulation pumps, booster pumps, boiler feed and fire pumps. Causes for failures of centrifugal pump mechanical seal.
The mechanical shaft seal is essentially a throttle arranged around the shaft. The mechanical seal acts as a check valve and a slider bearing. 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. Our mechanical seal inventory includes goulds centrifugal pump mechanical seals, roper pump mechanical seals, durco pump mechanical seals, flygt mechanical seals, and griswold pumps mechanical seals just to list a small selection of our extensive inhouse mechanical seal inventory. Mechanical seals areused throughout industryto minimizeor eliminate leakage in centrifugal pumps, mixers, and other rotating equipment.
At utex, we refer to this type as rs1 the assembly shown in the pump. Centrifugal pumps wate tc 9 4 ordering information 9 nominal impeller diameter pump model volute design rotation shaft seal fit impeller material model description order no. It reduces leakage between the pump and the surroundings to an absolute minimum. A mechanical seal is a method of containing fluid within a vessel pumps, mixers. The shaft seal is exposed to widely varying operating conditions. Mechanical shaft seal a mechanical shaft seal consists of two main components. A mechanical seal is a method of containing fluid within a vessel typically pumps where a rotating shaft passes through a stationary housing or occasionally, where the housing rotates around the shaft. Mechanical seal working animation types of mechanical seal. Loud blow is heard each time pump is started or stopped 20. The obvious function is that of a check valve to prevent liquid under pressure from leaking out of the pump, or from drawing air into the pump when under vacuum conditions.
When the sealing is achieved by means of packing, the chamber is referred to as a stuffing box. Probably the most widely recognized and also most common mechanical seal used in general service, low pressure applications. However, because of the delicate components used for this new sealing method, mechanical seal failures are the greatest cause of pump down time. Single spring mechanical seals for centrifugal pumps. The complete product portfolio of systems and components for cooling, flushing, pressurization and supplying liquid and gaslubricated mechanical seals e. The fact of the matter is that there are three types of problems mostly encountered with centrifugal pumps. If you are unable to identify the seal, it will be necessary for you to. Replacement seals for all your centrifugal and pc pump. Seal chamber pressure an overview sciencedirect topics. The mechanical seal employs a contacttype design to seal the centrifugal pumps shaft where it passes through the pump casing see shaft seal. Often a seal failure is diagnosed through visual inspection of the. Carbonceramic mechanical seal, ansi osha compliant guard, stainless steel pump shaft and a shaft jacking coupling to simplify maintenance.
Pump guidebooks are available in hardcopy or secure pdf format. Tandem double seals are usually employed in petrochemical and refinery plants, where service with high vapour pressure and low specific weight on centrifugal pumps is required. Shanley pump and equipment carries a full line of the most popular sizes and styles in centrifugal pump seals and progressive cavity pump seals ready to ship in stock the same day you order. T fire pumps mfg has been designing and building reliable, high quality portable fire pumps, foam systems and apparatus for over. Hydrodynamic seals article itt goulds pumps is a leading. Centrifugal pumps single impellerin aisi 304 7 cdx specifications liquid handled type of liquid clean water max temperature c 60 cdx 700570079010 standard 90 standard 110 cdxh and cdxhs standard min temperature c 10 maximum working pressure mpa 0. Here are 6 of the most common reasons mechanical seals can fail. Mukesh sahdev, associate content writer presented at the chemical engineers resource page. Mechanical seal failure phenomenon and analysis pump mechanical seals are available in a wide variety of models, there are five main leak points.
Single seals without connections sno, with flush sn and with quench combined with lip seal qn or throttle ring tn additional variants available for ansi pumps e. This fourth paper in the troubleshooting series deals with mechanical seals. The mechanical seal is the shaft seal device of the centrifugal pump, which has the advantages of small leakage and long life. Grundfos has many years of experience with the development, production and use of mechanical shaft seals in pumps, and our solutions in this field are contributing significantly to our leading position within pump technology.
Basics concepts of operation, maintenance, and troubleshooting, part i by. After sealing design of centrifugal pump, its mechanical seal is improved greatly, and improve the efficiency of the centrifugal pump. Mechanical face seal replacement how to use this catalogue locate the manufacturer of the equipment. Introduction the mechanical seal acts as a check valve and a slider bearing. Sealing systems for pumpssealing systems for pumps part i. A mechanical seal, figure 1, consists of a stationary member seat. When sealing a centrifugal pump, its essential to allow a rotating shaft. Whyend viewend view continuous seal chamber venting on vertical pumps. Standard mechanical seals are usually component seals. As a comprehensive manufacturer of pumps, torishima has never lost sight of the importance of mechanical seals.
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