How to Select Tube Fittings Image Credit: DK-LOK U.S.A. | Ark-Plas® Products, Inc. | Jergens, Inc.   Tube fittings connect runs of tubing (for in-line, offset, multi-port, and mounting configurations) to other tubing sections, pipe, hose, or other components. Systems are typically configured with straight sections connected by fittings or specially formed connections and joints.   Tubing vs. Piping and Hose To begin, it may be important to distinguish some...
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Q & A on Tube Fittings

We asked our users for their input on Tube Fittings. Here are the results of 209 users familiar with Tube Fittings.

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 tube fitting design?
25 answers
Answers:
In pharma a move away from off line sampling to in line sampling reducing the need to transfer samples away from line. Radar level measurement moving away from differential pressure measurement. Upgrade in pvc tubing and quick release fittings older push fittings were prone to heat failure and early failure, tubes worked loose unless an insert was used to maintain tube circular evenness.
~P J O C, Engineering Consultant, Cork, Ireland
Plating technologies are influencing tube fitting designs. Corrosion resistance requirements are increasing, so are the suppliers use of different plating materials to reach these requirements. Also, new connection styles for larger tube and pipe connections are becoming more prevalent.
~Jeff K, Marketing/Sales, Atlanta, MN
In automotive I think products out of Europe seem to be a challenging me as reseller and hands on repairs constantly need to adapt to new designed vehicles. Adaptors are made from cheap plastic and hard to get something compatible.
~Deon V, General Management, Gosford, NSW, Australia
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Q:
From your perspective, which companies are creating the most innovative tube fittings?
31 answers
Answers:
Not many in Australia. Italy has a good line of cheap Stainless Steel threaded pipe fittings, good for general low to medium pressure applications. Prices comparable with standard steel fittings of similar type and sizes. High pressure S/S are available but very expensive. Needs a range in between.
~Ray W, Engineer, Sydney, Australia
I may be biased, but Parker's Tube Fitting Division has a number of innovative products and characteristics versus their competitors. Second to Parker would be Voss.
~Jeff K, Marketing/Sales, Atlanta, MN
Clippard Industries, Swagelok ,Ham-let control Technology, Walterscheid.
~Deon V, General Management, Gosford, NSW, Australia
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Applications and UseTop

Q:
What are some of the applications you have used tube fittings for?
44 answers
Answers:
1 Hydraulic and pneumatic fittings for motion and gauging assembly machines. 2 Pneumatic fittings for leak test and pressure testing. These checking processes are for checking porosity, seal tests, gauging and part verification. 3 fuel lines and pneumatic lines on motorcycles.
~Micheal M, Senior Mechanical Engineer, Auburn hills, MI
I am using tube fittings for many application like pneumatic panels, mini batch reactors, spectrometer and for many other application which all are for compact design apart from I am in manufacturing highly precision QRC for gas application
~Technical Support/Services, Secunderabad, India
Air supplies Process sampling on shore and offshore (gas and liquid applications) Hydraulic applications on injection moulding/cold headed metal presses/high speed packaging lines valve actuators on bulk pharmaceutical.
~P J O C, Engineering Consultant, Cork, Ireland
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Q:
Please share with us any “non-standard” applications that tube fittings have been used for.
15 answers
Answers:
For medical device manufacturer, we made manufacturing fixtures called patient simulators plumbed creatively using tube products.
~J-dub, Research & Development, Seattle, WA
Sometimes tube fittings are used with over specification, and sometimes specification is not matching with tubing itself.
~Naeemuddin A, Facilities Manager, Fujairah, UAE
Pressure testing of small-bore piping (1"-6"). Connection to test pump for hydraulic delivery.
~Hilton L, Technical Support, Mossel Bay, South Africa
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Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of tube fittings?
19 answers
Answers:
Jointing in Composite materials is usually hand laid up and not technically researched. Joints are usually overdesigned and bulky which is not a bad thing, you don't hear of a lot of failures in composite. However, cost and availability is always a consideration and better methods with guaranteed strength would be a great step forward.
~Ray W, Engineer, Sydney, Australia
Brass fitting was installed in a medium pressure circuit. The fitting failed, the ship lost its steering and the ship crashed into a Miami bridge. The tugboat company went bankrupt to avoid the fine. The state replaced the bridge for $11 million. The fittings were in the steering cylinder for the tug boat.
~FRED O, Marketing/Sales, MIAMI,
Yes, high pressure hydraulic failure is not something to take lightly. The proper fitting style should be reviewed for every application (size, temperature, application, media, pressure, and end configurations all need to be considered).
~Jeff K, Marketing/Sales, Atlanta, MN
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FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
25 answers
Answers:
A well designed machine made, moderately priced. Tees, Elbows, Connectors ETC in a good range of sizes, made from a high strength composite material such as Carbon fibre or glass fiber using O ring seals or high strength glued joints. Not necessarily flanged joints that are expensive to manufacture and require additional jointing materials etc.
~Ray W, Engineer, Sydney, Australia
I wish that a wide variety of assembly tools (holders, grippers, compression tools, etc.) were available for a given product line and that the products were designed to be easily and quickly implemented with those tools.
~J-dub, Research & Development, Seattle, WA
Light weight, corrosion resistant, and the ability to hold 6K psi worth of pressure across all sizes. O-ring face seal and bite type connections are probably the best for sealing.
~Jeff K, Marketing/Sales, Atlanta, MN
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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 tube fittings?
26 answers
Answers:
Choose tube and port connections that separate the sealing requirement from the mechanical holding requirement. Splitting up these two functions with different characteristics of the fitting design is to the end user's benefit. Using fittings with soft seal technology is better for long term leak prevention.
~Jeff K, Marketing/Sales, Atlanta, MN
When using taper threads on fittings use a thread sealant not teflon tape as it can leave small pieces in the lines to block valves and orifices etc. Don't over tighten fittings with taper threads into alloy valve bodies as it will crack the valve.
~Rodger Trounson, Marketing/Sales, Invercargill, NewZealand
Know your application specifications such as media, flow requirements, system pressures (max operating, impulse, working), port sizes, and any unique requirements. Only by knowing all these parameters can the tubing and fittings be recommended.
~Robert Keller, Marketing/Sales, Suwanee, GA
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Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using tube fittings?
24 answers
Answers:
Yes, low pricing usually is a main driver for selecting a tube fitting supplier. I'd suggest making sure quality is up to snuff, as a low price today won't lead to lowest long term cost for upkeep. If OEMs sell a quality system, don't be scared to pay for a quality product.
~Jeff K, Marketing/Sales, Atlanta, MN
Cheapest isn't always best. You get what you pay for. (beware low cost imports) Buy your tubing from the same manufacturer as the fittings, this way you are assured the same quality standards are used.
~Robert Keller, Marketing/Sales, Suwanee, GA
Do not skimp on the fitting specification wrt line pressure specify correct material for process conditions match threads to avoid unsealable leaks use proprietary sealant on high pressure lines
~P J O C, Engineering Consultant, Cork, Ireland
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