Description   Mechanical seals are designed to prevent leakage between a rotating shaft and its housing under conditions of extreme pressure, shaft speed and temperature. Mechanical seals can be single acting or double acting. Single (acting) mechanical seals have one sealing gap.   The lubrication film required by the sliding seal faces is provided by the medium to be sealed. The lubrication film required by the seal faces in double (acting) mechanical seals is provided by a...
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Q & A on Mechanical Seals

We asked our users for their input on Mechanical Seals. Here are the results of 125 users familiar with Mechanical Seals.

Who Took Our Poll? | Design Trends | Applications and Use | Features | Buying Advice

Who Took Our Poll?Top

Design TrendsTop

Q:
What new technologies are influencing mechanical seal design?
20 answers
Answers:
New coolant additives Running higher pressures and temperatures New seal materials for greater reliability
~Tom O, Mechanic, Kamloops, Canada
Teflon material. Most of them provide products whose parts are not readily accessible.
~Tony E, engineer, Abuja, Nigeria
The use of man made diamond coating for seal faces.
~Perry W, Marketing/Sales, Sydney, Australia
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Q:
From your perspective, which companies are creating the most innovative mechanical seals?
19 answers
Answers:
John Crane / AES SEAL
~Technical Support/Services, Pantego, TX
Vulcan, AESSEAL. First4seals
~Nikola B., Technical Support, Daruvar, Croatia
John Crane Eagle Burgmann Chesterton
~Ashok C, Manufacturer, Mumbai, India
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Applications and UseTop

Q:
What are some of the applications you have used a mechanical seal for?
34 answers
Answers:
Water pumps, crude oil, various chemical applications, confirming to API Standards. Seals have been component type and cartridge, single and double on occasion with seal support systems such as barrier fluid tanks or cyclone separators according to various API plans.
~Marketing/Sales, San Juan, Trinidad and Tobago
Hydraulic and pneumatic cylinder shafts, pump shafts, gear boxes, drive shafts, differentials. Usually repairing/replacing worn out seals, repairing leaks.
~GlobalSpec Registered User
7.750" Shaft Size Type 81T Seals for a Split Case Pumps for the City of Corpus Christi. 2.625" Shaft Size Type RO Seals for Cowboy Stadium.
~Technical Support/Services, Pantego, TX
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Q:
Please share with us any “non-standard” applications that a mechanical seal has been used for.
10 answers
Answers:
High pressure high temp app on a subway car drive system with rubber tires generating high heat in a city with a year round ambient temp of 30 degrees C
~Sid F, Marketing/Sales, Toronto, Canada
Rotocone dryer seal where shaft is expanded by 6-7 mm in running and comes to its original position when equipment is standstill.
~Ashok C, Manufacturer, Mumbai, India
Combining seal and seats from different manufacturers to restore obsolete engine pumps, such as 1940s vintage Cummins Engine.
~Bill R, Marketing/Sales, Anacortes, WA
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Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of mechanical seals?
9 answers
Answers:
Early Sherwood 27XX series pumps w/silicone carbide seals had, in a one month period, 4 major failures. As these were vessels in transit, a quick fix using ceramic seals allowed the owners to continue their trips. Current production pumps have a different, but similar seal that is much more dependable. Seize-up problems not an issue with new seal.
~Bill R, Marketing/Sales, Anacortes, WA
It is common to hear of an Engineer trying another product from a series of different companies to solve a problem. Each time blaming the previous supplier for inferior product. This suggests that the site people do not understand the problems they have. All recognised manufacturers make a high quality product, but if it is mis-applied, then premature failure will be the outcome. Repeatability is of prime importance. As equipment ages, seal life will reduce due to a variety of reasons: equipment condition of spigot fits, bearing housing dimensions, component balance, alignment, bad installation practice etc. If a seal fitted to a new pump provided 3 years life, then this life should be repeated after each replacement. If it does not provide the same life, then the assumption should be that something has changed.
~Perry W, Marketing/Sales, Sydney, Australia
Yes, an o ring being sucked into a vacuum chamber causing catastrophic turbo molecular pump failure
~Research & Development, Santa Clara, CA
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FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
10 answers
Answers:
Seals with simple conversion from one design to another, using the same basic hardware. Seal designs able to withstand extreme operating conditions and continue to perform. A range of mechanical seals with built in electronic output capable of alerting to incorrect operating conditions such as dry running, incorrect pressure etc.
~Perry W, Marketing/Sales, Sydney, Australia
Alignment issues with seal regarding bearing wear. A more flexible seal may not be possible, but would be nice.
~Bill R, Marketing/Sales, Anacortes, WA
To design and develop critical seals rather than mass production. Get specified worldwide for special seals.
~Ashok C, Manufacturer, Mumbai, India
Easy installation and easy maintenance with low quantity of components.
~SANDRO B., Manufacturer, Padova, Italy
Multiple sizings and materials for the same application.
~Tom O, Mechanic, Kamloops, Canada
Simple, easy to install and low to zero maintenance.
~Sid F, Marketing/Sales, Toronto, Canada
O ring for all products and temperatures.
~Engineering, Other, Bolton, England
Easier to understand when specing
~Engineering, Design, St. Johns, Canada
More durability
~Alaa I, Facilities Manager, Jeddah, Saudi Arabia
Unlimited life!
~Rick G, Director of Operations, Seattle, WA

Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of mechanical seals?
9 answers
Answers:
First, understand the capabilities of the organisation providing the product information. If it is simply a sales organisation, then they may only offer or quote products they stock or have access to versus a company looking at the real problems of use across a site, then suggesting the best outcomes for that site. The first requirement is to fully understand each application and what is required to ensure the selected seal will operate in that environment. The mechanical seal cost is insignificant when measured against unplanned outages and associated costs for incorrect selection.
~Perry W, Marketing/Sales, Sydney, Australia
Keep in mind that seals are designed to "seal" and most of failures are due to bad mechanical conditions of machinery and/or bad selection.
~SANDRO B., Manufacturer, Padova, Italy
Don't select a seal on price alone. The maintenance cost associated with a bad choice out ways all the upfront saving very, very fast!
~Rick G, Director of Operations, Seattle, WA
Our experience with some silicone carbide seal indicate a flooded suction is required to prevent seal from seizing up and leaking on raw water pump applications, on marine engines.
~Bill R, Marketing/Sales, Anacortes, WA
Define the operating conditions, and service requirements in DETAIL, prior to selection. Search the existing literature and talk to an applications expert.
~Research & Development, Santa Clara, CA
Do not purchase copycat products. understand your equipment and fluid characteristics before selecting the seals.
~Ashok C, Manufacturer, Mumbai, India
Be sure they are durable. Most of them do not withstand the fluid as the case may be which they promised.
~Tony E, engineer, Abuja, Nigeria
Make sure you understand the conditions and chemical make-up of the fluid you are trying to seal.
~Sid F, Marketing/Sales, Toronto, Canada
Respect manufacturer indication, Seals Handbook
~Dorin, Appliocations Engineer, Elgin, IL

Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using mechanical seals?
14 answers
Answers:
Form a local relationship with a recognized mechanical seal supply / repair facility, capable of providing sealing solutions for specific applications versus simply a seal supplier. The company should be able to provide site surveys, seal recommendations, seal standardization across the site, engineering drawings, complete application detail and total ongoing support for repair and best return on investment.
~Perry W, Marketing/Sales, Sydney, Australia
If a factory installed seal fails prematurely, and there's no issue with installation, don't be afraid of subbing out a different seal material, to see if it's an engineering error in specing the wrong material for a given app.
~Bill R, Marketing/Sales, Anacortes, WA
Seal selection for any mechanical seals will be based on the product properties and pump design.
~Sami Al-mubarak, Technical Support, Saudi arabia, Saudi arabia
Always have shaft size ready and the medium you are pumping,with temperatures and pressures
~Maintenance/Facilities Management, Chagrin Falls, OH
Research and clearly understand material compatibility as it relates to the application.
~Rick G, Director of Operations, Seattle, WA
We have own school for learning about mechanical seals to end user and pump designer.
~Nikola B., Technical Support, Daruvar, Croatia
Before selecting seal, check its material chemical reaction with fluid in your machine.
~Alaa I, Facilities Manager, Jeddah, Saudi Arabia
Talk to several seal suppliers and different types of seal suppliers.
~Crosby H, Manufactures Representative, Huntersville, NC
Search the existing literature and talk to an applications expert.
~Research & Development, Santa Clara, CA
Purchase the seals who have design and trouble shooting knowledge.
~Ashok C, Manufacturer, Mumbai, India
Know the fatigue life of the elastomer used.
~Sid F, Marketing/Sales, Toronto, Canada
Price is not first important, but quality.
~Andy Xu, Purchaser, Dandong, China
Use good seals, tested, as SKF etc.
~Dorin, Appliocations Engineer, Elgin, IL
Stay away from China made products.
~SANDRO B., Manufacturer, Padova, Italy


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