EBerspacher BN-4 Pressure regulator diaphragms

[Angleofattack]

Time to report again! My diaphragm is running well... year and a half! Starts and burns like when I installed.

If you need one, I still have a few left before I have to start printing again.
+1 USA 404 747 1294

[raygreenwood]

I have watched this cool thread and refrained from comment because you are doing great work!

A couple of comments that may help you! I am glad your diaphragms are still working!

1. Your NinjaTek/NinjaFlex materials are all Urethanes or Urethane blends. They are classified at TPU (thermoplastic urethane's). A few of the really soft ones like the Chinchilla are TPU and TPE blends (thermoplastic elastomer).

Of note:......both Urethanes and nitrile in general.....are terrible with both normal gasoline and ethanol. They will sooner or later fail.

But......you are getting away with it and may get "good enough" lifespan out of the TPU Ninjatek material.....because its not cast or molded as a resin. Its a "thermoplastic"in the form you are using it in....so the surface is a good bit better sealed against attack.

2. I mentioned nitrile because last year you mentioned using a nitrile o-ring.

Nitrile general nitrile.....has no business in a fuel system......not because of the gasoline itself but specifically because of the of the ethanol.

In fact...most Urethanes cast from resin also do "decently" with standard non -ethanol gasoline. But the combination of the chemical soup of gasoline....plus ethanol and absorbed water.....are terrible for both materials.

But again.....due to the fact that the urethane you are using is a TPU....and its strictly its use as a "thermoplastic/thermo-set" instead of a cast resin.....I think you may get enough life out to make it worth your while.

If you still need to use an o-ring like mentioned last year....use viton.....or if that is too hard in durometer......use a fluorosilicone o-ring. If that is too expensive.....you can use HBNR. Those are the green o-rings you find in AC systems and some intake manifold gaskets.

It is Hydrogenated or "high saturation" nitrile rubber. It has resistance to oils and fuels and better than average resistance to ethanol.

HBNR is typically used to fill a gap between something like a urethane, regular nitrile or neoprene that are missing some chemical resistance and high temperature resistance.

While HBNR does not work as high as viton temps and it not quite as oil proof....it can work constant at 325-350 F......and its MUCH better with ethanol thqn viton.

Ray

[Lionhart94010]

This Might work?

THIN NITRILE COATED NYLON DIAPHRAGM DATASHEET - BS2751

PRODUCT DESCRIPTION

Our thin nitrile coated nylon diaphragm sheeting is a high-quality material that combines excellent resistance with durable physical properties. The nylon fabric reinforcement serves to increase the strength and durability of this diaphragm material without compromising on flexibility. This enables our material to provide an impressive life expectancy even in physically demanding applications. The Nitrile rubber outer provides excellent resistance against mineral oils and fuels as well as a wide operating temperature range. This enables you to use our material in a number of automotive, fuel pump as well as valve applications. Our thin nitrile coated nylon diaphragm material is available in a variety of thicknesses from 0.25mm to 1.20mm. Aside from full rolls we can also supply this particular material in strip cut lengths and bespoke gaskets.

We regularly supply our nitrile coated nylon diaphragm sheeting for use in a number of diaphragm sealing applications. Common uses include; pumps, valves, gas control equipment and carburettors. However, our nitrile diaphragm material is also suitable for use as a flexible strip, critical sealing gasket, insulating barrier as well as isolating application....

POTENTIAL APPLICATIONS
Thin gauge diaphragm sealing applications
Automotive carburettors
Gas control & valve equipment
L.P.G. & methane gas actuators & regulators
Diesel & other fuel pumps
Gas & fuel metering equipment

THICKNESS WEIGHT TENSILE STRENGTH ELONGATION AT BREAK
0.25mm 390 80 30%
0.40mm 500 130 30%
0.50mm 650 175 30%
0.75mm 850 300 30%
1.00mm 1150 300 30%
1.20mm 1600 300 30%

https://therubbercompany.com/rubber-sheeting/diaph...m-sheeting
_________________
Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 2015 GSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC, 72 KG GT that now lives in Australia, 12 JSW TDI, 2015 GSW TDI, 2023 Tiguan
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm

[Angleofattack]

I just wanted to report that my NINJAFLEX 3D printed diaphragm has been running flawlessly for 2 years already.

Just incase anyone needs one, I have a few extras or print more.

My BN-4 works so well that I can't think of replacing it with a modern one, even if it is noisy and can't control it by remote or thermostat...

[busdaddy]

That's good news!

It's not hard to add a thermostat in the circuit between the dash switch and relay on the heater, you'll need one made for RV's to overcome false triggers if you squirm around at night. There are also remote controlled relays sold for fog lights and other auto accessories that would work fine for the heater too.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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Слава Україні!

[Lionhart94010]

FYI you can add a thermostat to your BN4, it was an option...

25 1179 32 00 00 Eberspaecher room thermostat

wiring diagram

A single pole thermostat has a singular switch that opens or closes the heating circuit. Opening the circuit stops power flow to the heater. While closing the circuit lets power run to the heater, so it can regulate room temperature. This is how a thermostat reaches its setpoint...
_________________
Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 2015 GSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC, 72 KG GT that now lives in Australia, 12 JSW TDI, 2015 GSW TDI, 2023 Tiguan
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm

[Angleofattack]

In January 2020 I installed the Ninjaflex 3D printed diaphragm and it has been running strong for 3 years already. I start my BN-4 at least once every two months...

[notchboy]

[raygreenwood]

Very nice to hear!

Ray

[clhiller]

Angleofattack was nice enough to send me a couple of diaphragms. I got one installed and as of yesterday, it is approx 1& 1/2 months and still running just fine.
Jeronimo, your swag is in the mail!

[Angleofattack]

Today I smelled gas when I started my BN-4 for a regular "exercise" (It is 80F today in Atlanta). I smelled fuel. After 3.5 years, my 3D printed diafragm failed. Not the material, but mechanically, and due to a design issue that I can't easily solve. So I will just print another one and move on with another 3 years or so. Good enough for me.

[busdaddy]

So.., a 2 year life span, still better than nothing at all.

Thanks for posting about the failure, although a little disappointing it's good to stay ahead of potentially serious issues, it's good to have an option even if it's calendar life limited.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[notchboy]

[Angleofattack]

So I looked at the failure in detail, and I believe I can improve significantly the design. 3.5 years is plenty anyway even with the original design.

I have added material to the base, and I will try to remove the sharpness of the cup washer. Also, the material failed in "delamination". I will increase the printing temperature little more.

Again, I thing these are more than acceptable at 3.5 yeas of sitting in the heater.

[raygreenwood]

Yep, and in actuality that pr9bably really is a material failure.

The problem with these rubber types...Any rubber for that matter....is burn through time....which can be made worse by flexing.

So, the thinnest spots are going to burn through and get weak the fastest.

I do not consider it a failure. I also agree.

2 years is excellent. If you can make them cheap enough, just treat it like any other consumable maintenance item. I bet the thickened flange makes a difference.

Good work! Ray

[notchboy]

[Angleofattack]

[busdaddy]