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`Air Operated Diaphragm Pumps

`Air Operated Diaphragm Pumps

`Air Operated Diaphragm Pumps

Hi all,

I am pumping a mixture of oil and water, and sometimes dirt out of a sump and into a tank (from the tank it will be gravity fed through an oil/water separation process.  I have been told that the best pump would be an air operated diaphragm pump, as it will not emulsify the oil.  I need to specify the pump and air compressor, but do not have a good `standard' spec to start from....anyone know of a good source?


RE: `Air Operated Diaphragm Pumps

Try the leading pump manufacturers such as Wilden or Sandpiper. They may have a typical specification or if you ask nicely one that a major company has asked them to meet.

RE: `Air Operated Diaphragm Pumps

caochk, Most any type of positive displacement pump will minimize turbulence and hence emulsification within the pump. I've spec'd. progressing cavity pumps from Robbins and Meyers for just this application. Depending on the AODD check valve design, and flow rate through the pump, the check valve can develop enough turbulence to cause mechanical emulsification in shear sensitive fluid streams.

As for AODD pump manu'f. see the above, or check with Ingersoll Rand ARO pumps.  

Also, make sure that the piping is designed correctly to minimze any flow turbulence; i.e., Reynolds number significantly below the turbulent flow regime. Also use the minimal number of fittings, valves, strainers, etc. that can cause turbulence.

Hope this helps.

RE: `Air Operated Diaphragm Pumps

I'd agree with saxon and go with a progressing cavity pump, particularly if you have to buy an air compressor just to drive the AODD pump - that's like buying a car to tow a bicyle instead of just buying a motorcycle.  I've installed Moyno PC pumps for this reason, transferring a mix of sandy oil & water (surface runoff) from storage tanks to wastewater treatment facilities.  I'd be hesitant to say most any PD pump would minimize turbulance though, a gear pump or a diaphragm pump with a contour plate are pretty effective mixers.

If you do go with AODD, however, I'd say Wilden and Ingersoll Rand are your best bets.

RE: `Air Operated Diaphragm Pumps


In my opinion, your choice of pump type depends a lot on how often you have to perform the task.

If the pumping must be done on a frequent basis, ( about daily) then "scipo" and "saxon" are probably correct.....Just be prepared to purchase an expensive pump.

If the pump-out is infrequent AND you have the capacity in your air system, AND you do not want to pay a lot for the pump, go with the AODD.

Also if you have an NEC Class-1 Div-1 (explosive) area the AODD will be the best choice.....

Gimmie a star.......


"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  

RE: `Air Operated Diaphragm Pumps


You may want to consider using a mechanically driven diaphram pump similar to the type commonly used for dewatering at construction sites.  If such a pump is operated with relatively low shaft speeds, the flow rates and fluid turbulence can be more precisely controlled in comparison to AODD pumps.

You may want to consider peristaltic pumps as another possibility.

AODD's have many suitable applications, but from the information that you provided, AODD pumps would be well down on my list of potential choices.

RE: `Air Operated Diaphragm Pumps

Hi coachk
  I share MJCronin's opinion. In my platform, all the slop oil pump and chemical injection pump are AODP pump. it mainly depend on these factor below.
  1. Corrosion (AODP pump will have good performance if adequate material of diaphagram and valve have been seclected.
  2. Class of your pump location. (just like what MJCronin said "Also if you have an NEC Class-1 Div-1 (explosive) area the AODD will be the best choice". My ADOP pump is located in explosive area.)
  3. frequency. in my application, AODP pump is runned intermittently.
  4. Cost. the price of ADOP pump is cheaper than others. but if you have to buy the new air compressor for it, I don't think it is a good idea. you should compare with other pump.
  5. Maintaince (now my ADOP pump need replacing the diaphragm every half year.)
    Above, I only tell you about my application. I hope it is helpful to you.
                                                David yang
                                                Dec 27, 2003

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