High Side Chinese Filter Dryer Hack

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R

rnabholz

Member
Apr 5, 2017
49
1
Iowa, United States
I wanted to address the high side drying out of my Shoebox Max, but $400 was a bit too much after the compressor purchase. I had heard about the chinese filter and was very interested when I read on another forum of a member named Killfire's hacks.

$68 delivered for the filter, another $22 shipped for the Zeolite media, 253mm's of 1" Schedule 40 PVC and 2 o-rings.

Here are links to the filter and drying media

https://www.aliexpress.com/item/This-is-a-gift-free-of-mechanical-parts-the-link-is-used-for-customers-pay-the/32602913439.html?spm=2114.10010108.1000013.1.5EMraA&traffic_analysisId=recommend_2088_1_82199_new&scm=1007.13339.82199.0&pvid=24f0717b-8e8e-4d6d-995c-d71f67844578&tpp=1

http://www.ebay.com/itm/311845008955?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

The filter as shipped comes with a paper tampon the runs the length of the cartridge. 

The changes made include lining the cylinder with a PVC sleeve, and adding the molecular sieve media between shortened sections of the tampon material.

I just finished assembling it - took some pictures along the way that you can see here:

http://www.homebuiltastronomy.com/HighSideFilter/

Just did a quick pressurization of the hose, filter and fill hose. It took the Shoebox Max about 16 minutes to pressurize the system from 0 to 4450psi, where the Shoebox shutoff mechanism kicked in.

No signs of any leaking, no odd noises or cracking sounds coming from the filter.

So far so good.
 
Im sorry if I sound uninformed. But I am. But I want to learn more considering I just got a new Air venturi compressor. This filter goes after the compressor hose and connects to another hose and then directly to your gun or carbon fiber tank correct? Taking any extra moisture away from the tank being filled? If that is correct why did you modify the moisture filter? Also wouldn't moisture get between the pvc and the original tube wall? I don't think that big o-ring is going to stop it from getting behind it. Please let me know how it works and why it needed to be modified. Thanks.
 
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Thanks for the interest.

I am by no means an engineer, but this is my reasoning arrived at by looking at other approaches and my reading.

First, yes, this attaches to the output of your high pressure compressor or booster.

I think that most agree that the molecular sieve is the most effective approach for this task.

The paper tampon can act as a pre-filter and also prevent any dust from the media from leaving the system.

The PVC liner prevents moisture contact with the side walls, by all reports, an important protection against corrosion.

The length of the PVC liner was carefully measured and cut to create compression of the o-rings at the end of the PVC cylinder. It is a very snug fit. Do I know that it might not leak a bit? Can't be 100% positive, but I do think it will direct a good deal of the flow in the intended direction.

That is my reasoning. Hope that addresses your questions.

Rod
 
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My pleasure, glad you found it useful.

Once I had the pieces gathered, it only took about an hour to measure, cut and assemble, pretty simple.

Here it is in place.
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Very interesting and well written article, thank you for the pointer to it.

I come away with a couple of thoughts as it pertains to this filter on my set up, please feel free to comment, correct, expand etc as necessary.

First, it seems that the 13x desiccant is a good choice for this duty. High capacity, and in the quantities we need, reasonably priced.

Second thought is regarding the back pressure valve and dwell time. Obviously, the filter as configured does not have that valve, and so one would assume that the dwell time would be very short, as without the resistance of that valve early in the run, the compressed air would simply pass through the filter too quickly for the desiccant to have time to do its job. But not necessarily.

In the case of my use scenario, topping off SCBA bottles, I think there is force at play that effectively acts like a back pressure valve, and that is the pressure from the bottle containing 3000psi or whatever level that I am topping off from to 4500psi.

If I open the bottle up at the beginning of the fill run, the air from the bottle will back fill through the microbore hose, fill the filter and exit out the filter hose to the Shoebox, where it will meet the pressure from the output of the compressor.

If I wait to open the bottle until the pressure in the filter and hose is approaching the pressure in the tank, or perhaps slightly lower, it should balance and slow the movement of the air through the filter, increasing the dwell time significantly, especially at the relatively slow production rate of the Shoebox.

If I have that right, it would seem to be a viable approach.Thanks again for the link to the article.

Rod
 
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Rod, your logic is right on the money. Pressure Maintaining Valves or PMVs really aren't necessary for the filter to work properly unless a tank is being filled from empty as when dive shops fill tanks from empty. The back pressure from a PCP owner's tank on a typical top off is 3K so the PMV isn't even utilized. Your filter is going to be efficient whenever
you're topping off your tank.
 
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"Humdinger"Rod, your logic is right on the money. Pressure Maintaining Valves or PMVs really aren't necessary for the filter to work properly unless a tank is being filled from empty as when dive shops fill tanks from empty. The back pressure from a PCP owner's tank on a typical top off is 3K so the PMV isn't even utilized. Your filter is going to be efficient whenever
you're topping off your tank.
Click to expand...
I also agree with this logic. One of the reasons I opted to use the Diablo Molecular Sieve filter on my Shoebox outlet over the more expensive filter with the gauge and PMV. I routinely rejuvenate the filter media and inspect the filter internals and cap threads for any signs of corrosion. To date the Filter is in pristine, like new condition. This may also be due to my efforts to prevent water from reaching the Shoebox (Refrigerated Air Dryer, various in-line water separators, Coalescing and Desiccant filters).
Larry

bc6a7da4d1b33b71f31676303eb7a4b7.jpg
 
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"Humdinger"Rod, your logic is right on the money. Pressure Maintaining Valves or PMVs really aren't necessary for the filter to work properly unless a tank is being filled from empty as when dive shops fill tanks from empty. The back pressure from a PCP owner's tank on a typical top off is 3K so the PMV isn't even utilized. Your filter is going to be efficient whenever
you're topping off your tank.
Click to expand...

Thanks for the sanity check, as I said above, I am no engineer...

I do think this will work just fine for my needs.

Thanks again,

Rod
 
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Bleudg

II also agree with this logic. One of the reasons I opted to use the Diablo Molecular Sieve filter on my Shoebox outlet over the more expensive filter with the gauge and PMV. I routinely rejuvenate the filter media and inspect the filter internals and cap threads for any signs of corrosion. To date the Filter is in pristine, like new condition. This may also be due to my efforts to prevent water from reaching the Shoebox (Refrigerated Air Dryer, various in-line water separators, Coalescing and Desiccant filters).Larry

bc6a7da4d1b33b71f31676303eb7a4b7.jpg
Click to expand...

You have a great looking set up there Bleudg.
I am glad to hear your Diablo is holding up so well, and you think I am on the right track. From your earlier posts, you seem to know your way around these moisture control systems.

Thanks for responding.

Rod

 
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I received my filter housing today. Not bad at all considering it cost a total of $69.61 delivered and came from the other side of the world. Just 8 days from the time I placed the order, until it arrived at my house. For those who are interested, I measured the interior diameter of the tube, which was 1.380" or 35.05mm. I plan to machine upper and lower aluminum fittings that will then be attach to a section of 1" pvc pipe. The assembly will act as a refillable filter cartridge. The design will be based on the type of cartridges used by Joe B. in his alpha filter, but slightly longer and a little wider. His filter cartridges, which are disposable, appears to be identical to those used in many smaller dive compressors like the Coltri MCH6 and Max-Air 35, pictured below. 
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When I get my filter cartridge made I'll post a picture.
 
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Had time today to make my filter cartridge for the Chinese tube. As usual it took 3 times longer than I anticipated, but it seems to work and from now on I can just refill cartridge with fresh molecular sieve 13x and then reinstall it in the Chinese tube.


I ordered some fittings off ebay and from August Industries, https://www.augustindustries.com/shopdisplayproducts.asp?id=62&cat=Special+Fittings , to make a drain valve at the bottom of the Chinese tube. This is probably overkill and don't anticipate any fluid to actually drain from the Chinese tube as upstream from the Chinese tube is both a water collector and another molecular sieve filter. Downstream from the Chinese tube is Joe B's alpha filter. Like I said probably a little overkill for airgun use.



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