Author Topic: 3/4" needle valve  (Read 360 times)

mikenash

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3/4" needle valve
« on: June 13, 2021, 08:31:15 PM »
See pics?

I have been looking at needle valves and they're not cheap

But gravity-feed isn't demanding and so a cheap Chinese one might do the trick?

I attach a link - should be easy to google


https://www.trademe.co.nz/Browse/Listing.aspx?id=3128518899

Cheers

mihit

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Re: 3/4" needle valve
« Reply #1 on: June 15, 2021, 08:00:28 AM »
Is there a whole question in your post ??

What's the application?

veggie

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Re: 3/4" needle valve
« Reply #2 on: June 15, 2021, 03:18:30 PM »

For what you are doing (WMO feed regulation) it should be fine.
The only issue with needle valves for WMO is the tendency to clog due to the fine passages around the tip of the needle.
Stringy bits can cause a obstruction very quickly.
So ... make sure your oil is well filtered. Maybe down to 5 microns.

veggie
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mikenash

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Re: 3/4" needle valve
« Reply #3 on: June 15, 2021, 08:24:39 PM »
Hi Yes, I have a 4 micron filter drum.  But my oil is effectively "new" anyway - I've had no issues to date with blockages

What I have is gearbox oil with no combustion by-products or casual mixing with engine filter bits or brake fluid or whatever - and then diluted a little with diesel as I establish what works & what doesn't.  Its only contaminants are metal particles from gear wear - and I'm hoping that by letting 200-litre drums stand for a few years and then just using the top 80% or so, that these will simply "gravity out".  It seems to be very, very non-hygroscopic - when we drain gearboxes there tends to be a teaspoon or two of "clean" water in the bottom if the water-trap diaphragms have failed; but there doesn't seem to be mixture

I'll bring the feed assembly home this weekend and fit that valve below the existing isolating valve.  I'm keen to see if I can get an improved drip consistency within the limits of temperature/hydraulic pressure etc

Mihit - no, no question.  Just an observation - there had been some conversation around the use of needle valves.  But good-looking ones are expensive - so I'm keen to have a play with this Chinese cheapie

Cheers

cseyfert

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Re: 3/4" needle valve
« Reply #4 on: June 18, 2021, 07:58:07 PM »
Hi Mike,

That one you linked is for hydraulic service and has a one-way check valve in it.  Gravity won't open the check, so unless you can remove the check valve I doubt it will work.

veggie

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Re: 3/4" needle valve
« Reply #5 on: June 18, 2021, 10:44:53 PM »
Hi Mike,

That one you linked is for hydraulic service and has a one-way check valve in it.  Gravity won't open the check, so unless you can remove the check valve I doubt it will work.

cseyfert,  ... Good catch !

Mike .... remove the check valve  ;D
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

mikenash

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Re: 3/4" needle valve
« Reply #6 on: June 20, 2021, 08:32:54 PM »
Hi guys

lol check-valve yes.  Maybe it needs to come out - we'll see

But it blows air through at mouth pressure OK . . .

We'll see lol

mikenash

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Re: 3/4" needle valve
« Reply #7 on: June 24, 2021, 01:16:26 AM »
Hi Mike,

That one you linked is for hydraulic service and has a one-way check valve in it.  Gravity won't open the check, so unless you can remove the check valve I doubt it will work.

Hi guys

That cheap little valve is good as it is - no mods needed

The tank is only about 250mm above it, but will adjust and stay consistent anywhere from a very slow drip to a stream of whatever size is wanted

I'm keen to fit it and have a play

I attach links to two very short, very crappy-quality, but quite self-explanatory vids

Cheers

https://www.youtube.com/watch?v=l48gI_QLZ4Y

https://www.youtube.com/watch?v=DubHK5jnVt4

veggie

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Re: 3/4" needle valve
« Reply #8 on: June 25, 2021, 04:57:05 AM »

Mike,

Your videos are set as "private" and are not viewable by us mere mortals  :(
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

mikenash

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Re: 3/4" needle valve
« Reply #9 on: June 27, 2021, 08:28:38 PM »
Sorry, Duh