Fuel tap, blocked or restricted?

[Dougy]

I have a stainless steel fuel tank with a Saunders tap. I removed tank to clean etc and whilst flushing out a bit of diesel noticed the fuel only dribbles out from the tap, now is this restricted for a reason or is it full of crud, before I take it off, take it apart and no doubt end up having to buy another..would anyone know if this is restricted or should it free flow. It is gravity fed system if that helps?

 

[RichardS]

It looks like a gate valve design. I can't imagine why a gate valve would be restricted in such an application. You should be able to poke around with some flexible wire and see if that clears it.

Richard

 

[Dougy]

It looks like a gate valve design. I can't imagine why a gate valve would be restricted in such an application. You should be able to poke around with some flexible wire and see if that clears it.

Richard

Thanks Richard.
I have poked some wire in and it seems solid, I'm of the opinion that if it isn't restricted, the valve isn't opening or its solid...either way it's got to be taken apart...and added to the " things taken apart and never put back together" shelf...

 

[VicS]

It looks like a gate valve design. I can't imagine why a gate valve would be restricted in such an application. You should be able to poke around with some flexible wire and see if that clears it.

Richard

No its not. It is a Saunders diaphragm valve!

Used them often enough as sample valves but I cannot remember if these little ones are a weir type or not,

I have poked some wire in and it seems solid, I'm of the opinion that if it isn't restricted, the valve isn't opening or its solid...either way it's got to be taken apart...and added to the " things taken apart and never put back together" shelf...

Either way you wont poke a wire straight through it!

Simple enough to take the bonnet and diaphragm off to look inside, check operation clear any blockage and reassemble if serviceable .

 

[RichardS]

No its not. It is a Saunders diaphragm valve!

I've never heard of a Saunders diaphragm valve. What is the advantage of such a valve over a ball or gate valve?

I was right about one thing though .... it looks like a gate valve.

Richard

 

[<152587>]

Relies on a nitrile diagphragm to bear against the in/out to constrict the flow. Common in the petro chem industry

 

[penberth3]

Relies on a nitrile diagphragm to bear against the in/out to constrict the flow. Common in the petro chem industry

Yes, diaphragm means no moving parts in contact with the fluid.

I thought these were oil-resistant, but could your diaphragm be the wrong material, swelled up and disintegrated in contact with the diesel?

 

[Dougy]

No its not. It is a Saunders diaphragm valve!

Used them often enough as sample valves but I cannot remember if these little ones are a weir type or not,



Either way you wont poke a wire straight through it!

Simple enough to take the bonnet and diaphragm off to look inside, check operation clear any blockage and reassemble if serviceable .

As usual, amazed at the knowledge on this site, thanks guys, will take it apart the weekend.

 

[Dougy]

Relies on a nitrile diagphragm to bear against the in/out to constrict the flow. Common in the petro chem industry

Brilliant, thanks. Now I know It's supposed to have a restricted flow, I'll gently take it apart and clean.

 

[VicS]

Brilliant, thanks. Now I know It's supposed to have a restricted flow, I'll gently take it apart and clean.

No the flow will not be restricted when its fully open. You should see a full bore flow

What 3rd engine was describing was how it closes

Google for Saunders valves and you will see the general principle of their operation described.

You will also see how very unlike gate valves they are.

 

[penberth3]

Brilliant, thanks. Now I know It's supposed to have a restricted flow, I'll gently take it apart and clean.

No, it isn't supposed to have a restricted flow. The valve should open to allow full bore flow.

Screwing down the wheel constricts the flow, as "third engines" says, then stops the flow when the diaphragm is pressed onto its. It will all be obvious when you take it apart.

 

[Dougy]

No the flow will not be restricted when its fully open. You should see a full bore flow

What 3rd engine was describing was how it closes

Google for Saunders valves and you will see the general principle of their operation described.

You will also see how very unlike gate valves they are.

Thanks with do.

 

[RichardS]

You will also see how very unlike gate valves they are.

Apart from the fact that they look like gate valves.

Richard

 

[VicS]

Apart from the fact that they look like gate valves.

Richard

Sorry they dont look at all like gate valves. If you could actually see the OP's or had a better picture of it you would realise how silly that statement is .

 

[RichardS]

Sorry they dont look at all like gate valves. If you could actually see the OP's or had a better picture of it you would realise how silly that statement is .

But I only have the OP's picture to go on ..... and it seems that you now agree that, in that picture, it looks like a gate valve. :encouragement:

Richard

 

[VicS]

But I only have the OP's picture to go on ..... and it seems that you now agree that, in that picture, it looks like a gate valve. :encouragement:

Richard

Wrong again. I don't agree that it looks like a gate valve. Even that picture is unmistakably of a small Saunders diaphragm valve. A fairly old one maybe

 

[Tranona]

Think it is the actuator wheel that is similar to that on a gate valve. The body however (even in the photo) is completely different reflecting the different internals.

 

[VicS]

Think it is the actuator wheel that is similar to that on a gate valve. The body however (even in the photo) is completely different reflecting the different internals.

It was actually the little hand wheel that told me it was a Saunders valve. The design is, as far as i know, unique to those small Saunders valves. You cannot read it in the picture but IIRC the name is embossed on it. Thats probably how the OP identified it.

Larger valves had different hand wheels.

 

[Tranona]

Yes google saunders valve images shows a whole range of different shapes and styles - something i never knew existed. Another (almost) useless piece of information to clutter up my brain!

 

[RichardS]

Wrong again. I don't agree that it looks like a gate valve. Even that picture is unmistakably of a small Saunders diaphragm valve. A fairly old one maybe

You seem so deadly serious Vic .... can we have a few smileys, please.

Of course, to be "wrong again", one has to be wrong the first time.

Richard