How to Select Dynamic Seals   Image Credit: Applied Metrics| Daemar    Dynamic seals retain or separate fluids, keep out contaminants, and contain pressure. They create a barrier between moving and stationary surfaces in rotary or linear applications such as rotating shafts and pistons. Dynamic seals fall into one of two categories, contact and clearance. Contact seals have the seal bear against its mating surface under positive pressure. Clearance...
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Q & A on Dynamic Seals

We asked our users for their input on Dynamic Seals. Here are the results of 114 users familiar with Dynamic 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 dynamic seal design?
17 answers
Answers:
Biofluids, alternate rod surface coatings, higher heat and higher pressures.
~Scott Barth, Design Engineer, Salt Lake City, UT
Material specification and sealing material design. Sad to say, these have not changed dramatically in the last 20-30 years.
~Ian Smith, Engineering Consultant, Houston, Brazil
Not exactly new, but ferro fluid high vacuum seals and welded bellows are ideal, but costly.
~Paul Decker, Design Engineer, Ronkonkoma, NY
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Q:
From your perspective, which companies are creating the most innovative dynamic seals?
17 answers
Answers:
Trelleborg Sealing Solutions, SKF
~Engineering, Design, Norwich, Great Britain
Ferro-tec, Rigaku, metal bellows corp.
~Paul Decker, Design Engineer, Ronkonkoma, NY
Trelleborg, Parker, SKF, Simmritt
~Technical Support/Services, Willoughby, OH
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Applications and UseTop

Q:
What are some of the applications you have used dynamic seals for?
32 answers
Answers:
Ultrasonic Scanner oil tank, low speed. Keeping fluids separate, motor oil/gearbox oil.
~Engineering, Design, Doha, Qatar
- centrifugal pumps, industrial large size fans for hot air - hydraulic seal in cylinder ( presses and molded machine )
~General Corporate Mgmt, Bologna, Italy
Vacuum / Atmosphere seals. Ferrofluidic sealing. Dynamic oring seals or lip seals don't work in this application.
~Doug S, Engineer, Bristol, UK
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Q:
Please share with us any “non-standard” applications that a dynamic seal has been used for.
6 answers
Answers:
Fire fighting pumps on dredging vessels. Sea water contains a lot of sand grains.
~Klinkhamer S, Engineer, Groningen, Netherlands
Semiconductor manufacturing equipment
~Doug S, Engineer, Bristol, UK
Rod wiper for large diameter rod and a lip seal for hydraulic swivel.
~Senior Project Engineer, Lexington, KY

Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of dynamic seals?
7 answers
Answers:
Fibreglass agricultural spray tank with mixer shaft seal body and packing gland constructed of aluminum, all other material stainless. Al alloy parts corroded rather quickly.
~John F, Apple orchardist, previously design Electrical Engr., Chelan, WA
The wear rings mentioned above can get into stick-slip friction issues and wear ring swelling issues.
~Senior Project Engineer, Lexington, KY
Mounting upside down!
~Phil C, Manufacturer, Rosmalen, Netherlands
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FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
14 answers
Answers:
High temperature, low friction, FDA approval, metal detectable.
~Engineering, Design, Norwich, Great Britain
High speed and pressure seal that has extremely long life and signals the end user when it is about to fail.
~Technical Support/Services, Willoughby, OH
Any seal that can fulfill my max OP constraints with a reduced cost and assembly/maintenance requirements. :)
~Engineer, Iowa City, IA
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Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of dynamic seals?
11 answers
Answers:
KNOW YOUR CHEMICALS KNOW TEMPERATURE RANGES UNDERSTAND THE TEMPERATURE INCREASE ON A COMBINATION OF SPEED, CHEMICALS AND FRICTIONAL HEAT. UNDERSTAND THE CHANGE IN DUROMETER FOR PRESSURES
~JOHN B, RETIRED, Bossier city, LA
Simple: follow the manu's usage recommendations and don't use a seal outside it's operating range, or for an application it's not meant to be used for.
~Engineer, Iowa City, IA
On hydraulic cylinder wear rings for large diameter long and stroke cylinders they need to run a lot more clearance than what manufacturers recommend.
~Senior Project Engineer, Lexington, KY
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Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using dynamic seals?
10 answers
Answers:
Ensure the material specification of the seal in the required temperature range covers all scenarios of application. Ensure all dimensions ID and OD are carefully selected
~Ian Smith, Engineering Consultant, Houston, Brazil
Make sure your hardware designs are absolutely specified correctly (read the literature on the seals before purchasing).
~Engineer, Iowa City, IA
Cheaper is not always better. Shaft surface finish is very important.
~Brian U., Engineer, Rochester, MI
Choose a supplier based on experience and capabilities, not pricing, and trust them to deliver suitable solutions.
~Marketing/Sales, Woodinville, WA
To stay in contact with others. "If I give you one dollar, and you give me one dollar too. Nobody is richer. But if I give you one idea and you give one idea too. We are both richer ! "
~Mika Tomic, General Management, Cuprija, Serbia
Follow the catalog or call for Engr support.
~Scott Barth, Design Engineer, Salt Lake City, UT
Don't go cheap...you pay for what you get!
~Drew D, Marketing/Sales, South Lyon, MI
KNOW COMPATIBILITY, DO RESEARCH
~JOHN B, RETIRED, Bossier city, LA
Make them easily serviceable
~Paul Decker, Design Engineer, Ronkonkoma, NY
Test
~Technical Support/Services, Willoughby, OH


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