making new sliding pump vanes
 

I'm rebuilding several Blackmer pumps that are used for diesel fuel. They
have outlets of 2.5" and pump about 70 gallons per minute at 375 RPM.

The pump housings are cast iron. I need to replace the pump vanes. The vanes
slide in a rotor that spins in an ellipitical housing.

The original vanes are made from a plastic molded composite material that
looks just like bondo. The pump company charges over $300 for a set of 6
vanes (rectangular about .375 thick x 4" long x 1" wide,) so it might be
more economical to make my own.

I've been considering canvas phenolic, delrin bar stock, or aluminum flat
stock. I figure I can mill a batch of these vanes in short order.

Any comments or suggestions appreciated on the materials selection.


Tony

making new sliding pump vanes
 

On Fri, 28 Sep 2007 20:41:39 -0400, "Tony" wrote:

I'm rebuilding several Blackmer pumps that are used for diesel fuel. They
have outlets of 2.5" and pump about 70 gallons per minute at 375 RPM.

The pump housings are cast iron. I need to replace the pump vanes. The vanes
slide in a rotor that spins in an ellipitical housing.

The original vanes are made from a plastic molded composite material that
looks just like bondo. The pump company charges over $300 for a set of 6
vanes (rectangular about .375 thick x 4" long x 1" wide,) so it might be
more economical to make my own.

I've been considering canvas phenolic, delrin bar stock, or aluminum flat
stock. I figure I can mill a batch of these vanes in short order.

Any comments or suggestions appreciated on the materials selection.

The vanes in small air motors are often linen phenolic, so as long as
phenolic is compatible with diesel I'd think it would be a good
choice.

--
Ned Simmons

making new sliding pump vanes
 

Ned,

I made vanes for a DoAll bandsaw blower from canvas phenolic material.
There were 4 vanes about 2'x2' My stock machined rough and fuzzy
so I made the vanes a little oversized and lapped them dry with fine
wet
or dry paper on a flat surface. I got a nice close fit in the rotor
slots
and the vanes turned out dark and shiny. They worked fine.

Your 6 vanes are bigger so it would be more work but it can be done.

Regards, Charlie

making new sliding pump vanes
 

On Sat, 29 Sep 2007 04:56:24 -0700, wrote:


Ned,

I made vanes for a DoAll bandsaw blower from canvas phenolic material.
There were 4 vanes about 2'x2' My stock machined rough and fuzzy
so I made the vanes a little oversized and lapped them dry with fine
wet
or dry paper on a flat surface. I got a nice close fit in the rotor
slots
and the vanes turned out dark and shiny. They worked fine.

Your 6 vanes are bigger so it would be more work but it can be done.

Regards, Charlie

Coincidentally, I've also had the air pump on my 1948 DoAll ML apart.
It was several years ago, but as I recall the vanes appeared to be
some sort of carbon or graphite composite. The pump wasn't working
because the dust from the vanes wearing was interfering with the
vanes' fit in the rotor. I cleaned it up, put it back together, and
it's still working fine. Pretty good for a 60 year old saw.

--
Ned Simmons

making new sliding pump vanes
 

One thing i've noticed over time in rebuilding these pumps is that grit and
metal filings seemed to get embedded in the composite plastic vanes
(probably debris that got passed the strainer) and scores the pump
housings.

I was leaning towards aluminum vanes since I think they are less likely to
do damage to the cast iron housing. Brass or bronze might be even
better/longer lasting.

Tony


"Ned Simmons" wrote in message
...
On Fri, 28 Sep 2007 20:41:39 -0400, "Tony" wrote:

I'm rebuilding several Blackmer pumps that are used for diesel fuel. They
have outlets of 2.5" and pump about 70 gallons per minute at 375 RPM.

The pump housings are cast iron. I need to replace the pump vanes. The
vanes
slide in a rotor that spins in an ellipitical housing.

The original vanes are made from a plastic molded composite material that
looks just like bondo. The pump company charges over $300 for a set of 6
vanes (rectangular about .375 thick x 4" long x 1" wide,) so it might be
more economical to make my own.

I've been considering canvas phenolic, delrin bar stock, or aluminum flat
stock. I figure I can mill a batch of these vanes in short order.

Any comments or suggestions appreciated on the materials selection.

The vanes in small air motors are often linen phenolic, so as long as
phenolic is compatible with diesel I'd think it would be a good
choice.

--
Ned Simmons

making new sliding pump vanes
 

According to Tony :
One thing i've noticed over time in rebuilding these pumps is that grit and
metal filings seemed to get embedded in the composite plastic vanes
(probably debris that got passed the strainer) and scores the pump
housings.

I was leaning towards aluminum vanes since I think they are less likely to
do damage to the cast iron housing. Brass or bronze might be even
better/longer lasting.

Note that when lapping, the harder material is what is cut,
because the abrasive embeds in the softer material. So based on that,
you would want steel for the vanes.

But something like graphite which does not tend to accept things
embedding in it, but which wears to conform to the contour of the
housing would perhaps be the best choice.

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

making new sliding pump vanes
 

On 1 Oct 2007 02:28:00 GMT, (DoN. Nichols) wrote:

According to Tony :
One thing i've noticed over time in rebuilding these pumps is that grit and
metal filings seemed to get embedded in the composite plastic vanes
(probably debris that got passed the strainer) and scores the pump
housings.

I was leaning towards aluminum vanes since I think they are less likely to
do damage to the cast iron housing. Brass or bronze might be even
better/longer lasting.

Note that when lapping, the harder material is what is cut,
because the abrasive embeds in the softer material. So based on that,
you would want steel for the vanes.

But something like graphite which does not tend to accept things
embedding in it, but which wears to conform to the contour of the
housing would perhaps be the best choice.

Good Luck,
DoN.


The air pump vanes in my "torpedo heaters" use graphite vanes

Gunner

making new sliding pump vanes
 

Gunner Asch wrote:
On 1 Oct 2007 02:28:00 GMT, (DoN. Nichols) wrote:

According to Tony :
One thing i've noticed over time in rebuilding these pumps is that grit and
metal filings seemed to get embedded in the composite plastic vanes
(probably debris that got passed the strainer) and scores the pump
housings.

I was leaning towards aluminum vanes since I think they are less likely to
do damage to the cast iron housing. Brass or bronze might be even
better/longer lasting.

Note that when lapping, the harder material is what is cut,
because the abrasive embeds in the softer material. So based on that,
you would want steel for the vanes.

But something like graphite which does not tend to accept things
embedding in it, but which wears to conform to the contour of the
housing would perhaps be the best choice.

Good Luck,
DoN.


The air pump vanes in my "torpedo heaters" use graphite vanes

Gunner


Year ago I spoke to some people at Precision Scientific about why their
vacuum pump vanes went from graphite to metal. The reason I was told was
graphite allowed for a less accurate initial fit, and would wear into
place, but that wasn't a problem these days and metal vanes that last
longer if they're made to the right size the first time.