My understanding of modes of vibration / failure of drive shafts is as follows
1) Torsional
2) Lateral (with/ without rotation)
3) Whirl (of shaft, not bearings)
However there seems to be a lot of confusion about what is whirl and what is lateral vibrations, some sources say they are the same...
metengr
As I said at the start of the query, I was advised by other users of the steel forum to post here.
Not sure of the purpose of your post above.
Regards
sow
Posted on the stainless forum, was advised to post it here...
We have the following application:
1) Various large diameter valves.
2) Various large diameter pipes / manifolds.
The fluid in question is sewage with around 30% seawater.The temperature is 20 - 30 degree C (25 average).The...
We have the following application:
1) Various large diameter valves.
2) Various large diameter pipes / manifolds.
The fluid in question is sewage with around 30% seawater.
The temperature is 20 - 30 degree C (25 average).
The chloride content is 6500 -9500 (average is 8300).
We are...
Its covered in the EN regs by the nature of the gas -Ive done zoning before a good while ago and Im pretty sure it specifically covers stuff like diesel, no justification is needed, it is or it isnt.
Exercise the valves once in a while - if they are actuated do it in auto?
Do they have flushing points?
Gate valves - these are used a lot of solids applications (wedge for sewage, knife for slurry). I would imagine you could trial one from stores.
I’ve used RedValve type pinch valves on...
As somebody who manages other engineers, I can only say that some grads are pretty awful at taking on board suggestions for improvement, and you need to understand that you are asking him to take responsibilty for your work, he is there for a reason and therefore you have to produce work to his...
Ive seen plenty of works that pump the scum to the sludge tanks for mixing prior to thickening /dewatering or just straight to dewatering. Ask the suppliers of your dewatering equipment what they think.
Problem is that scum can take a lot of water to move and / or unblocking of pumps - but it...
You will get some presure back, but bear in mind that the more of a hump you have the more potential for -ve pressure you have + you need to ensure the "gravity" section is primed.
You need to draw the hydraulic profile and the pipe profile to make any sense of it.
I think that doing CAD for a while is an advantage for an engineer. It helps with practical design and helps to make you a more rounded engineer. I know a lot of CAD techs who earn more than engineers.
However I would think about how long I could do this before I was pigeonholed. What would...
MJ,
My opinion, for what its worth...
If you see your career in engineering management (within say 5-10 years) then perhaps you should do the management course?
If you see your role as being technical, for at least the next 5-10 years then you should consider the technical course. If so I...
I don’t think the idea is totally out of the question. Although fundamentally different I have seen these on raw water systems from reservoirs where the head is otherwise throttled to control the flow.
If the system is at the start of a long high pressure main then you may step down the...
the flow discharges into an empty main for 10 seconds at start up- the pumps are out on the curve and at full speed for this time and the power curve is rising.
The question was, would a temporary overload in power on the motor equate to a failure of the motor (by torque / thermal or other...
Waross - the pumps start up to full speed ok. Im not concerned about the increased current at this point, as we have soft starts to start the pumps. The issue is that the motor is overloaded for a "normal" operation after the pumps are up to full speed (and voltage) for around 10 seconds until...
Thanks for the replies -
The motor would be in this state for around 10 seconds every time the motor starts.
Could the overload result in
1) an overtorque or increased mechanical stress on the rotor bars.
2) thermal stresses on the rotor bars.
3) any other modes of failure in the rotor bars...
The question boils down to this -
The motors / pumps are up to full speed, they are out on thier curve, hence the power input (requirement)to the pump exceeds the rated power output of the pump.
What would be the affect of this?
You can get problems with the mechanical end of things at too high a turndown. The flow rate turndown will be much more than 10:1 therefore you could be looking at cavitation and thrust issues. Other kit has other problems, e.g. blowers suffer from overheating.
But then again so what? the...
The motors are 350kW
The methods are as yet unknown, and it is only really chatter to be honest.
The rotor bars are failing mechanically. Cracks have appearing on the rotor bars, close to the end rings.
We have a squirrel cage motor that is failing on its rotor bars around 1 year after commissioning. I understand that during commissioning there were some difficulties getting the pumps to start without a “failed to start” error on the soft start, and that the pump supplier employed some...
If there is a supplier involved ask them.
If there isnt then Wastewater Engineering by Metcalfe and Eddy gives a methodology for estimating losses through clean and dirty filters. These calcs are quite sensitive to assumptions and data available. I would compare this with data from existing...
