Alternative to dichloromethane for filter cleaning

What exactly is the [fuel?] filter for: gasoline, diesel, turbine, etc fuel?

Is Your filter 100%-all-metal with mesh screens and soldered, brazed or welded joints?

Does the filter have any non-metallic elements? Mesh, filter paper, adhesives, sealant, elastomers, etc?

What is the filtering capacity [down to what micron level of cleanliness].

What is/are Your visual, flow-rate and/or /\P inspection requirement(s) that determines the filter needs attention?

Cleaning is tricky/subjective and may require verification testing... Why clean it... WHY NOT replace it?

Some mostly relevant info...
SAE AIR787 Filter Element Cleaning Methods
SAE AIR887 Liquid Filter Ratings, Parameters and Tests
SAE ARP725 Evaluating Effectiveness of Filter Element Cleaning Methods




Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

It's an air-filter. So this is a Starter Valve, It's where the ground equipment would be hooked up to pump pressurized air to spin up a turbine to start a turbo-fan (CF6-80 on a 767) The valve is normally closed but opens when pressurized.

From the CMM:

B. The normally closed valve opens with supply pressure at a minimum of 11.9 psig when
the valve solenoid is energized with 28 vdc.
C. Servo supply air from the butterfly valve bore passes through the actuator supply orifice
to the closing actuator chamber. When the solenoid is energized, the servo supply air is
allowed to pass from the closing actuator chamber through the filter and through the
valve opening rate orifice into the opening actuator chamber.

The filter is a fairly fine wire mesh (all metal) that would strain out anything large enough to be visible without magnification that might prevent the regulator diaphragm from functioning at it's target pressures.

I think selecting a different solvent seems straightforward, but I wanted a sanity check to make sure I'm not missing some critical factor. I've asked Hamilton Sundstrand the same question, but they don't seem to respond to anything. I suppose I could replace the filter every time.

Thanks for your response Wil.

-Kirby



Kirby Wilkerson

Remember, first define the problem, then solve it.

Freon was the solvent of choice for many years in USAF US-cleaners. I suppose that Freon is no-longer an option... even with closed-cabinet recycling...?
Likewise... trichloroethylene [TRIC]… is also a 'favored solvent of choice' for many years in US-cleaners. Might be suitable even with closed-cabinet recycling...?

Also... while I'm thinking out loud.... what about P-D-680 [MIL-PRF-680]… there is at least one grade(s) that is that has been used in US-cleaners.

CAUTION.
AIR787 has a very important/in-depth discussion/info/precautions RE this topic. IT IS WORTH READING and knowing before treading in this area...!!!

QUESTION1.
Is Your filter element 'simply' woven fine-wire mesh made from CRES, Cu-Ni, nickel alloy [Inconel], etc... or is it welded/sintered/braised/etc across nodes? IF simply woven, be cautious about indefinite re-use.

DoD bought-into the concept of woven wire mesh filter-elements for the ability to be indefinitely re-cleaned. HOWEVER it was discovered that that woven mesh is subject to micro degradation at the wire-crossing nodes... especially with entrapped contaminates, heat, vibrations and flowing fluids [including air]. Microscopic flexing/rubbing/abrasion/corrosion-erosion tends to squash/abrasively thin-down wires at the nodes. The first notable change was mesh stretching/deformation at these nodes] that often resulted in screen layers laying/rubbing on each-other [which sometimes happened when abusively mishandled by mechanics]. Also, determining WHEN the element is 'clean-enough' requires testing. I am trying to ID the USAF T.O. for filter cleaning for other hints... can't seem to locate it.

What does 767, CF6 data say about this topic?

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

It looks like it's just woven. Here's a picture of the filter:



In pushing back I got our safety guy to okay purchase of the DCM. I am going to try and find a copy of the AIR787 and read it to learn more about filter element.

Thanks,

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.

Kirby,
Can you use Trichloromethane or is that as hard to get as Dichloromethane ?
B.E.

You are judged not by what you know, but by what you can do.

KW... That's a teeny-weeny filter element...

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

Can you use Trichloromethane or is that as hard to get as Dichloromethane ?

Click to expand...

It might be 3/2 = 50% harder to get.

(Couldn't help it)

Kirby,
Is the filter expensive? Just wondering if it's worth all of the examination it's getting.

Please remember: we're not all rednecks!

I'll ask about replacement. But filters that are normally just cleaned often end up hit or miss for being available for purchase. And if they are available in serviceable or as removed condition, I'm right back where I started in needing to find a cleaning process. Now I just need to get me a teflon bag so I can put it in the ultrasonic cleaner without changing the whole tank.

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.

KW... BTW... looking closely at your good quality close-up photo...

Right side 'edge' of the filter element... near the flanged-base and up about 1/3... there appear to be some [4 or 5] broken or stretched or dislodged... wires.

I suggest using a soft white cotton rag, or cheesecloth, to gently wipe the exterior of the element... much like inspecting a flight control [wire-rope] cable. I have a bad feeling that the cloth fibers will snag on these wires... which is sign of deterioration.

PS. The following USAF T.O. for inspection/testing/cleaning of reusable wire filter elements was rescinded in 2002. I suspect the DoD finally realized that filters are cheap... engines are expensive.

9H3-1-1 Cleaning and Testing Instructions for Woven Wire Hydraulic Filter Elements

PS, The practical side of me want's to agree with you... grounding an engine for a tiny filter that could be cleaned seems really wrong. STRONGLY recommend You get spares in the pipeline ASAP... but prepare for temporary returns to service.

WARNING1.
"There is nothing more permanent than a temporary fix.” --Russian proverb

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

A standard polyethylene ziploc will have adequate resistance to dichloromethane, which used to commonly be call methylene chloride. Teflon is unnecessary. Acetone is often a good alternative solvent, but flammable.

Wil,

Yes, I noticed that too. I'll pull out my microscope to get a better look at it.

Compositepro,

I was seeing that PE was not resistant to DCM. I was going to check it to confirm regardless. If it lasts long enough to do a part it's good enough for me and much cheaper then a teflon bag.

Thanks all,

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.