O-Ring Size for a dnp Coupler

[SeaCern]

Does anyone know what size o-ring a dnp PAV 13 F-1/2 NPTC 19 coupler uses? This is an Italian part. I have a micrometer that measures in inches. Converting to mm the best guess that I have is a 25mm x 20mm x 2.5mm. Before I order I thought that someone here might know.

This is the coupler series- https://www.dnp.it/images/PAV1_DNP_2021_compressed.pdf

Thanks

 

[oosik]

If you have the old 0-ring. Take it to NAPA, O'Reillys, etc and match it up.

 

[oldnslo]

Metric O-rings are typically sized by ID and cross section so in this case 20mm x 2.5 mm

American that would be very close to 0.103 cross section which is very common and .784 ID which is probably also close to standard size.

American sizes are frequently a 2-*** numbering system

 

[npalen]

While we're "at it", I would sure like to know what size o-ring is used in a 3/8" Type A coupler body as shown below:
I think it's a -115 size but not absolutely sure. I'm blown and replaced several of these in the last couple years due to pressure buildup caused by temperature change if I'm not mistaken.

3/8"3/8" NPT ISO 7241-1 Series "A" Quick Disconnect Hydraulic Couplings, Set of 10 | eBay

 

[npalen]

i've found that a -114 and a -115 size o-ring will work for this Type A 3/8" coupler. The -115 size, being slightly larger diameter is more difficult to install

My curiosity made me waste a coupler by machining it half away to get and actual measurement of the o-ring groove diameter as well as dropping both sizes of o-rings down into the groove to see the difference in fit.

It's now apparent, at least to me, that the smaller -114 is the proper size. Some may ask why I didn't just compare the original o-rings to get the size. Well, kind of a long story so will just leave it a that.

 

[oldnslo]

Npalen
Does that connector have a backup ring along with the O-ring or just an O-ring? Just curious since it seems like some models do and some don’t. My old Parker O-ring handbook shows pressure vs diametrical clearance and going from memory I believe.002 inch was 1500 PSI.

 

[npalen]

Npalen
Does that connector have a backup ring along with the O-ring or just an O-ring? Just curious since it seems like some models do and some don’t. My old Parker O-ring handbook shows pressure vs diametrical clearance and going from memory I believe.002 inch was 1500 PSI.

OLDNSLO Here is a pic showing the o-ring and backup ring with the male coupler tip installed:

The small chamfered holes are where the retainer balls would normally be located and the chamfers show the quality of machining on these china eez parts. The frazzled cut edges show the quality of my cutaway machining and lack of deburring thereof.

 

[oldnslo]

thanks Npalen,
Your cutaway machining is far superior to my hack saw. Getting the O-ring and back-up ring installed can be real challenge and keeping them in proper orientation even a bigger problem.

as a point of reference my Parker hand book shows the groove OD for the 114 to be .787 and the 115 to be .849.

 

[droptop]

I'm not sure that the coupling uses a standard size o-ring in imperial or metric. I found that the Parker version of this ISO7241A coupling has a specific part number just for the coupling o-ring. Normally this type of o-ring is also harder than the normal nitrile material. I can't be sure that the o-ring is the same in all ISO7241A couplings, but I don't see why one manufacturer would change it. The backup rings are also listed in the catalog.

https://www.mrostop.com/50001-211-0010-parker-quick-disconnect-seal

 

[npalen]

Guys, thanks for the feedback on this o-ring and backup issue!

Edit: I checked the o-ring groove diameter in the cutaway body and it measures about 0.830 which is in between what post #8 (oldnslo) shows for #114 and #115 o-ring groove diameters. So the Parker 50001-115-0010 is maybe the special o-ring size?
Gets a bit confusing.