Mechanical Run Test

[Rafael Dos Santos]

I have 2 questions regarding mechanical run test (MRT)

1.) What is rated flow? Cause in pump data sheet, there are minimum flow, preferred flow, and operational flow. So which one is used in MRT?
2.) Lets say we have the flow that we want and we run test. If the flow drop below minimum flow like 20 or 30 m3/h, is the test fail? but the vibration monitoring is good.

 

[mk3223]

Clarify what's the purpose of the MRT?
Suppose the pump tested is to run the flow at the different rates to verify the discharge head produced to ensure the pump can provide the flow-head performance based on the design requirement.

I don't think you need to test the pump below the pump minimum flow rate to show that no vibration damage. On the other hand, the pump my be damaged by the vibration if it is running "longer" time under the minimum flow rate as specified by the Pump Manufacturer.

 

[shashankTurbomachine]

MRT is done for 4 hrs formally.
But in actual it is only around 2 hours.

MRT is done because to check whether the pump is performing better at rated condition.
WIth MRT following is observed

[li][li]Bearing Temperature[/li][/li]
[li][li]Lube Oil Temperature and Pressure[/li][/li]
[li][li]Test Water Inlet and Outlet Temperature[/li][/li]
[li][li]Cooling Water in and out Temperature and Pressure (if any)[/li][/li]
[li][li]Bearing Housing Vibration (mm/s or in/s)[/li][/li]
[li][li]Shaft Vibration (μm or mil)[/li][/li]
[li][li]Shaft Speed[/li][/li]
[li][li]Power consumption[/li][/li]
[li][li]mechanical Seal Leakage rate[/li][/li]

The pump manufacturer provides the bearing housing vibration data and shaft vibration data. The review process is as the same of the performance test but in the mechanical run test; the test is done in the "rated flow," so one acceptance range will be used for all plots. The value of overall vibration and discreet vibration value shall be less than specified values in API 610 or approved test procedure.

A well phrased question has answers in itself!!!

 

[Rafael Dos Santos]

mk3223. If we see the trending from flow transmitter, we can see the fluctuation and sometimes,the flow drop below minimum flow but not significantly, just 20`30 m3/h. In this case, is the MRT not acceptable?



thanks shashankTurbomachine for the answer. It really helps me.

 

[mk3223]

Since the MRT is to test the pump at the "rated flow", how much fluctuation of the flow as observed during the MRT?
My question is that if the percentage of the flow fluctuation is complied with the Code or acceptable with the Client per pre agreement?

See attached paper for reference,

https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/162538/PumpTutorial1.pdf?sequence=1

 

[Artisi]

MRT under what operating conditions, would think the only test a customer would be interested in is operating on-site at about its required operating point.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)