Adapting Vacuum Pump Flared Fitting to NPT

CitrusFire

New Member
Help, I think Im loosing my mind trying to get my vacuum pump set up for my degassing chamber. I have this pump (LINK): and I need to adapt the 3/8" SAE flared fitting to NPT. Once I get an NPT fitting I'm good to go and now how I'm going to plumb everything else, but for some reason this adapting step is eluding me.

First I bought this flared fitting from McMaster (LINK), the size seems close but the male SAE on the pump doesn't go deep enough to engage the threads.

I thought maybe it was a 37 degree vs 45 degree problem so I bought a Female 37° JIC fitting from here (LINK), and in that that case the male flare doesn't even fit into the threads. What am I missing here?
 
Why don't you just use a hose between the pump suction and the tank? It's all you need.
Exactly. Be sure to add a ball valve in line in case you need to lock off the pump.
My repressurizstion valve is on here as well now rather than on the side of the chamber.

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Take the various bits to a company that makes or supplies hydraulic hoses tell them what you want to do and they should be able to deal
 
Take the various bits to a company that makes or supplies hydraulic hoses tell them what you want to do and they should be able to deal
That is what I ended up doing. You know that you will get the right stuff.

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I know this headache. I fix espresso machines, which are all plumbed in JIC (with metric hard-line just to make it extra spicy), but of course everyone's hookups are NPT.

JIC uses British parallel pipe threading, so that's why that fitting didn't work.

There are a bunch of hydraulic standards - and none of them really play nice with each other - but there should be an adapter fitting out there for you.


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Why don't you just use a hose between the pump suction and the tank? It's all you need.

Thats the problem, I can't even connect to the pump in the first place, because everything that seems like the female SAE fitting, isn't.

But yea, the answer is probably to play with everything in person.
 
I see.

Looking at that pump spec sheet and photo, it looks like it has all three sizes on there that are listed on the spec sheet. It also says they are ACME, which isn't something I'm familiar with for a piping connection. I know ACME threads as transmission screws, and they don't appear to be ACME threads in the photo. So, I'm not sure what they mean by ACME there.

They look like MIP threads under those caps. I'd be surprised if they were flared fittings, just based on the few pumps I've had and have.

In case it helps, here is a photo of a few adapters I have handy.

brass.jpg
 
Looking at the pump (couldn't open the link on my phone, can on PC) and I will suggest that one of the three is a 1/2 thread, one will be 1/4" thread and anyone's guess for the 3rd. My pump only has the two, 1/2" and 1/4".

What hose are you intending to use? In the end, I got steel reinforced hose as the plastic stuff that I was told would be OK crushed after 20"Hg. The guys at EnZed fitted spinning attachments that allow me to attach and remove the hoses.

Also what size chamber are you planning on using with this?
 
The vacuum hose doesn't have to be anything special. The inherent strength of a hose profile will let it work fine without any kind of special reinforcing. Just clear 1/4" ID tubing will work fine.

vacuum-hose.jpg
 
The vacuum hose doesn't have to be anything special. The inherent strength of a hose profile will let it work fine without any kind of special reinforcing. Just clear 1/4" ID tubing will work fine.

View attachment 770392

Yep that is what I was told too, and then it crushed in on itself at about 20"Hg. Some small vacuum systems (those 4.5ltre kits with the 3cmf pumps) come with that and it works fine. Not in my case.
 
I don't know why you had trouble, maybe it was your hose didn't have sufficient wall thickness. We use 2 commercial 220v two-stage Alcatel pumps that are far from small vacuum systems, have pulled hundreds of gallons of rubber, and never had a hose collapse.
 
I don't know why you had trouble, maybe it was your hose didn't have sufficient wall thickness. We use 2 commercial 220v two-stage Alcatel pumps that are far from small vacuum systems, have pulled hundreds of gallons of rubber, and never had a hose collapse.

Haven't had trouble for years (about 2 now?) since replacing the clear hose with a proper steel reinforced hose. Yeah, maybe the wall thickness was not thick enough. A non issue now and taking the system to the guys in the know, gave me a full working solution that has served me well.
 
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