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Will this pump work?
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Hi,
I need to find out if this pump will work for my Methoxide mixing.
It is a Sandpiper, model PB1/4 - A, type TS - 1 - PP. It is air powered (pneumatic).

The Manifold, Outer Chamber, Valve seat, and Outer Diaphragm Plate are made of PolyPropylene.

The Intermediate Housing, air valve and cap are made of glass filled polypropylene.

The Inner Diaphragm Plate is made of 2011-AL Aluminum.

The actual Diapragm and Ball Valve are made of Santoprene.

Miscellaneous other parts like the diaphragm rod is 416 Stainless Steel.

The pump is rated for 7 GPM.

I can get this pump VERY CHEAP, perhaps $50 or so. Even if it's not perfect, as long as it will work for a few months without 'melting' that would be fine as I'm a bit cash strapped right now.

What do you all think?

Thanks,
Dan

ImageWilden_Sandpiper.jpg (41 Kb, 29 downloads)
 
Location: Central California | Registered: April 24, 2010Reply With QuoteReport This Post
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I've heard those diaphragm pumps are good pumps, and will pump just about anything.
They also are well sealed. And, in this case, you won't have a motor, sparks, or wires anywhere close to your methanol.

You may get some heat from the reaction of the methanol and catalyst, but essentially no heat from the pump.

I have heard, however, these diaphragm pumps are air hogs.
 
Location: Oregon | Registered: October 17, 2007Reply With QuoteReport This Post
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If the aluminium comes into contact with the methoxiode it would dissolve the aluminium.
 
Location: Nimbin Australia | Registered: December 04, 2007Reply With QuoteReport This Post
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quote:
Originally posted by sinbad:
If the aluminium comes into contact with the methoxiode it would dissolve the aluminium.
I agree with Sinbad, keep methoxide and aluminium diaphragms separate or you will likely have problems.
 
Location: East Yorkshire | Registered: January 14, 2006Reply With QuoteReport This Post
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thanks, the Aluminum part does not contact the fluid being pumped. All wetted parts are Polypropylene and Santoprene.
I have heard differing opinions on polypropylene and have concluded that it can be used but is not the ideal material. But again, the price is right, any other pump would cost me double.
All thoughts are welcome.

Thx,
Dan
 
Location: Central California | Registered: April 24, 2010Reply With QuoteReport This Post
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Diaphragm pumps work well to move methanol. I use a Sandpiper pump to move methanol and methoxide. I have had two problems with the pump. Both related to polypropylene "wear" parts. The poly diaphragms soon cracked and the poly check valve balls swelled enough to stick and not seal. After replacing the poly parts with santoprene the pump has work great.

I did have a problem with a bad ball valve in the plumbing that made me think the pump had a problem again. But that is another story......
 
Location: Virginia | Registered: March 17, 2007Reply With QuoteReport This Post



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I do believe that pumping pure methanol with aluminum is not a problem.

If you add lye (hydroxide) to the methanol, then it becomes an issue. I think the hydroxide and aluminum react to form hydrogen gas and the aluminum gets chewed away in the process.


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Registered: March 09, 2006Reply With QuoteReport This Post
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To expand on Murphy's comment - pure methanol is OK with aluminum, but the presence of a very small amount of water will also give methanol a slight caustic nature, which will cause it to gradually corrode aluminum and (as well as copper).

This effect is nowhere near the same as with methoxide, which, as Murphy said, will eat up aluminum in a big hurry, but it will work on it gradually, which is why methanol specific pumps that are aluminum often have a nickel plating on them.

But, I suppose if you've got water in your methanol, you might have bigger things to worry about that gradual corrosion of your pump.


Galen Bowen
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Location: Chico, CA | Registered: March 26, 2006Reply With QuoteReport This Post
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quote:
Originally posted by Murphy:
I do believe that pumping pure methanol with aluminum is not a problem.
The OP (and the two replies about Aluminium) refer to "mixing methoxide" with this pump, not pumping pure methanol. These are absolutely different duties and should not be confused or compared as being anywhere near the same.

Having said that, what Murphy says is almost correct, the corrosion rate of Aluminium in contact with pure Methanol is very slow, although it is there so can be a problem if not monitored. Add water to that and the speed of corrosion is increased as Galen mentions.

All in all "most" engineers would not select Aluminium for long term Methanol duties and would certainly not select it for Methoxide duties.
 
Location: East Yorkshire | Registered: January 14, 2006Reply With QuoteReport This Post
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Thanks everyone.
I may be missing something, but as mentioned the one aluminum part is not supposed to be a wetted part. This is according to the manufacturer whom I called yesterday.

Based on FuelFarmers comment, this leaves the wetted polypropylene parts to be concerned about. Except, I don't know which ones are wetted. There are 4 polypropylene parts, I will list them again, can someone say which parts are wetted so I can look for a replacement santoprene part? Here they are: Manifold, Outer Chamber, Outer Diaphragm Plate and the Valve Seat.

I can pretty much figure that the manifold is wetted, and 'outer chamber' also sounds like a very major component. Whould switching these basically mean getting a different pump?

I hope I didn't make a mistake, I purchased it yesterday for $40.
 
Location: Central California | Registered: April 24, 2010Reply With QuoteReport This Post
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Update: upon speaking with the manufacturer again, the pump housing is basically made from polypropylene. Soooo...... erhmm..... Am I completely out of luck? Funny how the diaphragm and valve is santoprene yet the body is PP.
 
Location: Central California | Registered: April 24, 2010Reply With QuoteReport This Post
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The pump body is polypropylene on the pump I use. It seems to be holding up very well. If the diaphragm and check vale balls are santoprene you should be good to go. I think you will really like the pump

You got a good deal on the pump.
 
Location: Virginia | Registered: March 17, 2007Reply With QuoteReport This Post



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Jajada,

If my understanding is correct, and you will in fact be pumping methoxide, I would not use it if it has aluminum backer plates.

A diaphragm failure will cause the aluminum backer plates to get wet with methoxide. Key to this discussion is severity of the reaction that methoxide and aluminum will create. We're not talking about days here. It can take as little as an hour for a hydroxide mixture to chew away large volumes of aluminum. Do not underestimate the severity of the reaction.

In short, what this means is that if your diaphragm fails, you'll probably be replacing the backer plates also unless you catch the malfunction within minutes and can get the aluminum rinsed off.

I generally tell folks that aluminum has no place in a biodiesel operation at all.


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Registered: March 09, 2006Reply With QuoteReport This Post
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Thanks guys,
I have contacted the local distributor regarding a replacement inner diaphragm plate, but seeing that even the models that are made from Acetal and various other materials also use the same aluminum inner diaphragm plate, I don't think any other type exists for these pumps.
I think I will simply stay on top of the maintenance and reduce the chance of diaphragm failure. If needed the aluminum plate can be replaced as well if it eventually corrodes.
I hope this makes sense, but tell me, when aluminum and methoxide meet how violient / poisonous is the reaction? This is of course a pretty small piece of aluminum but.....
 
Location: Central California | Registered: April 24, 2010Reply With QuoteReport This Post
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quote:
Originally posted by jajada:
I hope this makes sense, but tell me, when aluminum and methoxide meet how violient / poisonous is the reaction? This is of course a pretty small piece of aluminum but.....

Hydrogen gas is produced fairly quickly which can be a whole lot worse to deal with than Methanol.
 
Location: East Yorkshire | Registered: January 14, 2006Reply With QuoteReport This Post
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Pure aluminium and methanol don't react but very little of the aluminium used by industry is pure.

They use so many different alloying materials(silicon zinc magnesium manganese....) that it is difficult to say which piece will be immune and which will slowly dissolve. I think manganese oxide will actually decompose the methanol?
 
Location: Nimbin Australia | Registered: December 04, 2007Reply With QuoteReport This Post
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I discovered that pumping very warm, dare I say hot, methoxide with a diaphragm pump does not work so well. I am thinking that on the suction stroke some of the methanol flashes to vapor and this keeps the chamber from filling properly. Who knew?
 
Location: Virginia | Registered: March 17, 2007Reply With QuoteReport This Post
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