4 replies to this topic

[eastorca]

Dear all,

Merry Christmas,

In my system, one pump shall be used to pump fluid from the Open drain tank back to Closed drain vessel.
Rated condition as follows:
Flow rate: 2.5 m3/hr
Discharge pressure: 1500 kPag

And, the NPSHavailable is 0.5 m.
My question:

- Is there a progressive cavity pump (electrical driver) that could comply above design conditions?

Thank you so much.

Regards.

[kkala]

I understand you look for a progressive cavity pump of about 11 gpm flow and 220 psi head, with low NPSHa = 0.5 m. http://www.moyno.com/1000pumps.html indicates that flow and head requirements could be realized. NPSHa=0.5 m is quite strict requirement for horizontal pump, since NPSHr is often 2 ft below NPSHa. The pump is self priming, but has also a NPSH requirement. A vertical pump of same type from Moyno would satisfy NPSHa, but flows start from 20 gpm up, while head is below 150 psi. Usually manufacturers can offer products somehow different to standard ones, which can be checked by contacting them. And competitors might offer vertical progressive cavity pumps to your requirements.
It seems that a market research is indicated to find if such pump is available in the market. Or information from others having specific experience on such pumps.

Edited by kkala, 27 December 2011 - 04:31 PM.

[ankur2061]

eastorca,

Progressive cavity pumps can work at extremely low suction pressures (even vacuum in the suction vessel). There is no NPSHa requirement in terms of difference in NPSHa and NPSHr. Progressive cavity pumps only require that the pump casing gets filled initially. Progressive cavity pumps can run with the difference in the NPSHa and NPSHr as zero. Recently on a project, progressive cavity pumps have been used for a similar application (drain collection vessel) where for a centrifugal pump we were getting only a difference of 0.2 m between the NPSHa and NPSHr due to limitations of layout of the vessel and the pump. A progressive cavity pump manufacturer has guaranteed a satisfactory operation even with 0.2 m difference between NPSAHa and NPSHr citing that his pump can operate at zero difference beweeen NPSHa and NPSHr. It is important to note that the application mentioned above is an intermittent operation and not a continuous one. Some links are provided for suppliers providing pumps for applications similar to yours:

http://www.seepex.co.../en/IN_OF_e.pdf

http://www.torqueflo..._guidelines.htm

Hope this helps.

Regards,
Ankur.

Edited by ankur2061, 28 December 2011 - 01:09 AM.

[kkala]

.......Recently on a project, progressive cavity pumps have been used for a similar application (drain collection vessel) where for a centrifugal pump we were getting only a difference of 0.2 m between the NPSHa and NPSHr due to limitations of layout of the vessel and the pump. A progressive cavity pump manufacturer has guaranteed a satisfactory operation even with 0.2 m difference between NPSAHa and NPSHr citing that his pump can operate at zero difference beweeen NPSHa and NPSHr. It is important to note that the application mentioned above is an intermittent operation and not a continuous one. ....

Can you please advise NPSHr and nominal flow rate of the specific progressive cavity pump referred? An horizontal pump is anticipated, is it so? Just to compare to NPSHa=0.5 m of present case.
What is the affect of intermittent operation? Self priming would facilitate it.
It is noted that Moyno 1000 pumps (web reference in the previous kkala's post) denote low NPSHr (not zero), but no arithmetic value has been found.

Edited by kkala, 28 December 2011 - 02:22 AM.

[eastorca]

Thank Kkala and Ankur so much for your information

My pump is intermittent operation. I am thinking of a vertical pump. It might the best solution.

eastorca,

Progressive cavity pumps can work at extremely low suction pressures (even vacuum in the suction vessel). There is no NPSHa requirement in terms of difference in NPSHa and NPSHr. Progressive cavity pumps only require that the pump casing gets filled initially. Progressive cavity pumps can run with the difference in the NPSHa and NPSHr as zero. Recently on a project, progressive cavity pumps have been used for a similar application (drain collection vessel) where for a centrifugal pump we were getting only a difference of 0.2 m between the NPSHa and NPSHr due to limitations of layout of the vessel and the pump. A progressive cavity pump manufacturer has guaranteed a satisfactory operation even with 0.2 m difference between NPSAHa and NPSHr citing that his pump can operate at zero difference beweeen NPSHa and NPSHr. It is important to note that the application mentioned above is an intermittent operation and not a continuous one. Some links are provided for suppliers providing pumps for applications similar to yours:

http://www.seepex.co.../en/IN_OF_e.pdf

http://www.torqueflo..._guidelines.htm

Hope this helps.

Regards,
Ankur.