What is "best" pump for waste oil applications

[rdeno]

I am stuck...at our facility, we use a Flowserve rotary gear pump to feed waste oil to our boilers which provides steam for our process. The oil is treated with sulfuric acid to help remove the Al fines and over the viscosity. The viscosity is between 20 to 50 cP and Al fines are around 20 microns or less, temperature is about 100 degrees F. So far, they have purchased several of the same pumps with the same result -- within two weeks it fails. I took the pump apart and did see mild scratches on the shaft but no gear damage. The pump is a 10 gpm at 100 psi, it uses a herringbone gear, and uses babbit bearings with the waste oil as the lubricant. The 10 Hp motor turns at 1800 rpm.

I feel the speed should be by half and the bearings should be lubricated outside the pump cavity.

 

[25362]

The Pump Handbook by Karassik et al. gives a troubleshooting chart on chapter 6.2.4 Gears that may be of help. I recommend you read it. The subject of exposure of bearings to abrasive substances, among other bearing causes of failure, is treated in this chart.

 

[EdDanzer]

Try a roller bearing gear type hydraulic pump running a lower speeds. Permco and Commercial are two common brand. Start at less than 500 rpm with your low pressure.

 

[stewbaby]

Contact some vendors of Roper, Blackmer, Gorman-Rupp, Goulds, Sulzer, Viking and ask them to see what solutions they can offer...sometimes they can even provide a trial pump at no charge or warranty a pump with money back guarentee...make these reps work for you.

The Viking Rotory Lobe type works well for us in acidic and gritty asphalt and slop oil services...

 

[CARF]

Try a monopump,

For pumping neutral or corrosive liquids, uncontaminated or abrasive liquids, liquids containing gases or which tend to forth, and liquids of high or low viscosity, including liquids containing fibrous and polid meterial,

There are many manufacturers around:

http://www.ctp.com.cn/monopump.htm

http://www.netzsch-pumps.com/

 

[mmmumuw]

What kind of filtering do you use? Residue is not too friendly to any positive displacement pump. You will have almost the same result if you just change the brand. May be you should request harder materials for the shaft.
1. Get rid the fines
2. use harder materials
3. lower rpm logically can extent the lifetime
4. Read Karrassik
hope can help.

 

[ccfowler]

You may want to consider progressing cavity pumps for this duty. Check out Moyno, seepex, etc., but be very conservative by staying close to the minimum speeds recommended by these manufacturers for you application. When dealing with the manufacturers or their representatives, be careful to fully disclose all of the information on your application.

 

[MJCronin]

redeno,

I partially agree with "stewbaby" above, a Viking pump may be best....I do not think a very expensive "progressing cavity pump" is appropriate

I think that you may be using the wrong type of "rotary gear" pump. Is your pump a "Flowserve GAX cast iron series, double-helical, herringbone type gear pump" ?

If so consider using an "internal gear" pump.....I have seen a lot of these on "dirty oil" service

See:

http://www.vikingpump.com/products/internal_gear_pumps/internal_gear_pumps.htm

MJC

"There comes a time in the affairs of man when he must take the bull by the tail and face the situation." W.C. Fields

 

[rdeno]

I spoke with a Viking rep and he suggested a HL-4625-R with "sale restriction" that my purchaser does not like. The pump being used is a external herringbone rotary gear pump.