Needle valve vs ball valve

[guypettigrew]

To get the wort from the mash tun to the boiler I use a Chugger pump with a three piece ball valve on the outlet.

It's really difficult to get the flow rate right. I want about 1/2 litre a minute. The ball valve adjustment seems too coarse to get this right, and the flow rate often trickles down to nothing all by itself. This means I have to constantly adjust the lever on the valve by tiny, tiny amounts.

Would a needle valve give me better control? This is the sort of thing I'm thinking of.

This has a NPT thread. Would it be compatible with the threads on a chugger and a 1/2" male hose barb?

Thanks.

Guy

[LeeH]

Yes it will but I just use a ball valve and seem to manage with a chugger.

The chuggers are NPT anyhow due to them coming from the US and you can normally make a BSP fitting ‘have it’ with some liquid thread sealant. I use a loctite branded one and never had a leak on a NPT thread.


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[guypettigrew]

Thanks LeeH

Needle valve ordered. It'll be a while until it gets here. I'll report back in 6 weeks or so.

Guy

[guypettigrew]

Problem solved-I think!

The ball valve on the Chugger outlet takes a standard 1/2" hose, internal diameter 12mm. I'd reduced this down to 8mm by pushing a few cm of the smaller diameter hose into the end of the larger hose.

I've now used a couple of very short bits of smaller ID hose on the hose barb on the ball valve outlet to produce a stepped reduction in diameter. This means I'm now running 4mm ID hose all the way from the ball valve to the boiler, instead of the reduction to 8mm which was previously just at the far end of the tube.

Hope this all makes sense!

I've just tried it with water at about 70°C. It was much easier to limit the flow to 1/2 litre per minute and this flow rate stayed constant over an hour. As long as hot wort behaves the same as hot water all will be well. Mind you, I might still fit the needle valve when it arrives just to see if it makes setting the flow rate even easier. The ball valve is pretty sensitive to tiny movements of the handle.

Guy

[LeeH]

Good times.

This is the reason why I built in speed control for my chuggers. I can make very fine adjustments by throttling back the pumps a few percent but I somehow manage on a ball valve OK on my system.


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