Screw Pump

Hi

You are quite right in that API676 which covers these pumps does not give specific acceptance criteria.

Noise limits are usually the subject of local legislation, but an overall limit of <85dBa would be reasonable and achievable if there are no other requirements.

API686, in the Machinery commissioning check sheet, states that "Overall vibration should be 0.15 inches per second true peak or less for each bearing".

This is also a reasonable number and is in line with API610 which gives unfiltered overall limit of < 3mm/s RMS with discrete frequency limit of 2 mm/s.

Hope this helps.

It seems VDI 2056 used to define the vibration for these as Group K below 0.027"/sec.

Could not get hold of this std, and seems to have been withdrawn and replaced with ISO 10816.

However ISO 10816 does not address to small machines.

It seems canadian std CDA/MS/NVSH 107 still addresses to this but not sure. The values are there in that range (VDI).

Took a long search to get these.

The noise level is to be mutually agreed upon - based on what the manufacturer had committed in the Pump data sheet.

For the duty specified by you ,it is quite normal to have a pump with noise level below 80 dB. Typcally a good pump should not have more that 75 dB!

This will also depend on the discharge pressure and suction conditions.

Triple screw pumps are manufactured by companies such as Allweiler,Bornemann,Leistritz - all from Germany,IMO from Sweden and USA and a host of other companies.

Usually the noise levels are for combined for Pump and motor unless you can accoustically isolate the pump.

The Motor noise is usually more than the pump noise ( due to the cooling fan).

Together the noise should be less than 80 dB.

trust this helps.

Regards

Cowlagi

HOLA POR LO GENERAL ESTA ES UNA VELOCIDAD ALTA 1200 RPM LO QUE NO ALCANZA A CUBRIR LA DEMANDA DE LA BOMBA, LO QUE SE RECOMIENDA ES UNA TUBERIA DE SUCCCION, LA INMEDIATA SUPERIOR.

ATTE ING FRANCISCO CASTELL

CASTELL@PRODIGY.NET.MX