pump flex hose ?'s

  • We are currently upgrading MFK. thanks! -neo
Redoog

Redoog

Candiru
MFK Member
Jul 29, 2009
313
1
46
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Boon, MI
ok so I am getting some vibration through the floor on my current setup. Not bad, but other then this my setup is silent.

So i figure i will use a piece of flex hose between pump and pvc to eliminate this.

Pump is a mag 9.5 and i think the outlet is 3/4 npt, i have a 3/4 barb, but it is for a 1/2 hose.

Is that the hose size you use? I will only use a 8" piece, just to break the hard line connection between the pump and the tank, like I said hopfully stopping the vibs being sent through the line where it touches the floors and whatnot.

http://www.monsterfishkeepers.com/forums/showthread.php?t=262743&page=18
 
The MD 9.5 has a 3/4" NPT outlet so you need to maintain this size by using 3/4" hose.
 
deeda, That is what i was thinking, not sure i can get barbs at lowes, will have to go check.

Here is an odd thing. threads are 3/4, so we always go with 3/4 pvc etc. But if you measure the inside of any 3/4 npt fitting, you will only have around 1/2 inch opening.

So i am wondering if in the future, I will not go ahead and use the inside diameter of the smallest piece. Which for the current tank would be 1/2 and not the 3/4 I used.
 
Pipe is measured in nominal sizes, 1/2", 3/4", 1", etc. The inside dimension will vary slightly between manufacturers and pipe wall thickness.

Where you will really notice a size reduction is when using a barbed adapter fitting. Your pump has a 3/4" NPT male fitting, correct? So you would need a 3/4" NPT female x 3/4" barb adapter. This allows you to maintain the internal diameter. If you were to use a 3/4"NPT female x 1/2" barb adapter, you would lose the internal diameter because you are changing sizes.

If you can't find a 3/4" NPT female x 3/4" barb adapter, use a 3/4" NPT threaded union to connect the pump outlet to a 3/4" male barb adapter.
 
yes i have the the proper fittings to do it.

I was just pointing out. All my plumbing is 3/4", and the holes i drilled for rugf have the same are as a 3/4" hole.

However, the inside diameter of all the 3/4" npt fittings I have is closer to 1/2". It has to be, because the threads are 3/4".

so what i was thinking was that a pump with a 3/4 npt outlet is restricted on flow to 1/2" hole right off the bat, so maybe bumping it back up to 3/4 is not as neccesary as i thought . maybe since the smallest hole is 1/2" I would maintain the 1/2" inside diameter throughout next time.
 
¾ pipe, PVC or other, would/should have an outside diameter of 1in.
1/4in. for the threads.
1/2in. I.D. will have an O.D. of 3/4in.
If you have 1/2in. I.D. fittings, with 3/4npt threads, they are adapters.
All pipe is measured by inside diameters..
 
your right, but if your pump has a female 3/4 npt outlet, ANYTHING you screw into it will have and ID of approx 1/2". Whne i get home i will shot some pics of what i am talking about.

There is no way that i can think of, to have a 3/4" ID fitting threaded into the 3/4" npt outlet of the pump. So the pump is restricted right off the bat to approx 1/2.
so if it is Approx 1/2" coming out of the pump, you could maintain the same constant flow by making sure every fitting and piep had and ID close to that of the smallest hole in the system, which would be at the pump outlet.

All i am saying is they prob calculated that whne they designed the pump,
 
female 3/4 npt outlet, ANYTHING you screw into it will have and ID of approx 1/2"

Your missing it.
3/4 npt, female holes are about an inch across to allow the pipe to still have a 3/4 ID with material to hold threads.
Same for male threads.
It can not be 3/4 pipe with 1/2 ID.
It can be 1/2 ID adapted to 3/4 npt, either male or female.
 
ok i will have to do some measuring when i get home. maybe this pump outlet is not a 3/4 , i did not have to buy any fittings, it came with them.

I am sorry.
You are correct, 3/4 npt have an O.D. of 1.050 which is the same as typical 3/4 pvc, so it wouldbe possable to cut thread into the pipe and maintain the same I.D.

Not what I have on this pump I bought which says it has 3/4 npt outlet. I did a quick measure before and the inside diameter of the fitting, which was not overly thick, was bigger then 1/2 but smaller then 5/8 doing a quick measure.
You got me thinking now that it is 1/2npt which has a o.d. of .840. I will check sunday night. I knew npt is differant, but was think unc threads, and got myself all screwed up. Thanks for setting me straight.

Again, sorry to be argumentative, and I stand corrected.
 
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