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ANALYSIS OF PUMP FLOOR FOR NATURAL FREQUENCIES.

 
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er.mvv
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PostPosted: Tue Apr 09, 2013 10:16 am    Post subject: ANALYSIS OF PUMP FLOOR FOR NATURAL FREQUENCIES. Reply with quote

Dear SEFIANS

  We are designing a heavy pump room consisting undergroung water compartments and pup floor is the top slab of these compartments. Pump floor is sheltered by roofing and walls. All elements are in RCC. Pumps are fixed to the floor slabs/beams with foundation bolts. All pumps are rotating about the vertical axis. Axial force and Torqe are supplied by the pump vendor. How to analyse the whole structure to evaluate the natural frequency to compare with the operating frequency to avoid resonance? Your valuable suggestions are appreciated.


best regards
     MVV
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Manoharbs_eq
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PostPosted: Wed Apr 10, 2013 7:36 am    Post subject: Reply with quote

Dear MVV Sir,

I have designed few of UG sump with pump room above and structurally supported on slabs.
We should ensure that the vibrations does not transfer to the structure completely, we have to place suitable dampers below the pump support.
generally not the operating frequency but first or fundamental frequency at the time of start is considered.

Swami saran text book on machine foundation has some information.


Rgds
Manohar
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jeet_singh23
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PostPosted: Fri Apr 12, 2013 8:03 am    Post subject: Reply with quote

Hi,
I understand that the pumps you are talking about are vertical pumps and not the tradiational horzontal types with shaft parallel to ground. Most probably a dynamic analysis may not be required if they are light, and maybe otherwise as well. The behaviour of vertical pumps w.r.t to the six degrees of freedom is totally different. If you know some one in Mechanical, please ask him to brief the principle of operation. This should help in better understanding.

Let me know if these are not vertical pumps.

Thanks.
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mtamil
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PostPosted: Mon Apr 15, 2013 6:26 am    Post subject: Reply with quote

Hi,

I have not designed supports for vertical pumps, supported on suspended beam-slab system. Howevere, below is my understanding.

1. Both the impeller and the Motor Rotar are rotating about the vertical axis.
2. suction line is alligned verticaly and delivery line is horizontal.

There are no exitation forces in the vertical plane and therefore the vibration and resonance is not critical in the vertical plane. However, the supporting Beam-slab system is to be designed for hammering effect, which will produce large impulsive vertical force. And beams/slabs shall be designed for this action.

Exitation do exist in the horizontal plane. In my opinioin, the stiffness in the horizinatal plane is very large and possibility of exessive vibration is remote. I am assuming a continuos slab system supported on all egdes.

So, the design can be simple static calculations, with additional loads discussed above.

I am eager to know the final design by MVV

Regards
Tamilarasan
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ibu_4_u
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PostPosted: Tue Mar 24, 2015 6:23 am    Post subject: Re: ANALYSIS OF PUMP FLOOR FOR NATURAL FREQUENCIES. Reply with quote

er.mvv wrote:
Dear SEFIANS

  We are designing a heavy pump room consisting undergroung water compartments and pup floor is the top slab of these compartments. Pump floor is sheltered by roofing and walls. All elements are in RCC. Pumps are fixed to the floor slabs/beams with foundation bolts. All pumps are rotating about the vertical axis. Axial force and Torqe are supplied by the pump vendor. How to analyse the whole structure to evaluate the natural frequency to compare with the operating frequency to avoid resonance? Your valuable suggestions are appreciated.


best regards
     MVV
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Rishi Singh Chhabra
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Joined: 29 Nov 2010
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PostPosted: Wed Mar 25, 2015 12:17 pm    Post subject: ANALYSIS OF PUMP FLOOR FOR NATURAL FREQUENCIES. Reply with quote

Sir,I want to know what are the experiments one can perform in laboratories to determine the moisture susecptibility of bitumen except Marshall flow test, Marshall stability test, stripping test on aggregates and bitumen?
Please reply!


    Thanking you in anticipation,
     Warm Regards,
     Rishi Singh Chhabra
     +91-9039528342

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