I am looking into developments in pumping technology and am looking at the potential improvements (or possible replacements - emerging technologies).
This is very much looking at pumping in the future, with improvements allowed because of advancements in existing technologies (for example...
I understand that there is a requirement, when carrying out a pressure test (during a statutory inspection) of a pressure vessel, to check it's expansion to ensure that it falls within certain limits. Is this correct to ensure CE compliance and does it apply retrospectively (ie old vessels)...
Rajanet is right
This is a very simplistic approach but heregoes. If you have a 5% year on year Discount factor
Year 0 Year 1 Year 2 Year 3 Year 4 Year 5
DF 1 0.95 0.91 0.87 0.83 0.79
Now all you do is multiply (money in - money out) ie what you have spent - what you have saved...
A commercial crane is usually proof load tested to 1.25 SWL.
I am a little bit puzzled why you you need to do a proof load test unless it is for a critical lifting application
Most commercial design codes assume a single test at the start of life and it is only repeated following significant...
Thanks Colcol,
I usually use a range of between 10% to 20% of the total engineering manhours to determine my PM costs. It is good to see that "my rule of thumb" looks appropriate.
Whilst we are talking about rules of thumb another one I use is that engineering manhours should usually...
I am interested to know from an initial costing point of view when a project is "sizeable" enough to require a full time Project Manager (or what percentage of the overall budget should be assigned to PM tasks). Should project management be costed in as a task in itself. Often in my...
dgunther,
From Machinery's Handbook for the situation you have described. Edge "supported" around circumference and a uniform distributed load over the surface of the plate:
d = 0.221 WxR^2/Et^3
(if the edge is fixed the multiplier changes to 0.0543)
Where -
d = deflection in mm...
Could anyone tell me if there is a statutiory requirement for the calibration of electrical equipment ie load cells. The reason I ask is that mechanial lifting equipment has a statutory requirement to be inspected annually. If a load cell is incorporated into lifting equipment does what...
Could anyone tell me if there is a statutiory requirement for the calibration of electrical equipment ie load cells. The reason I ask is that mechanial lifting equipment has a statutory requirement to be inspected annually. If a load cell is incorporated into lifting equipment does what...
ASME NB-3531 now calls for a hydrotest pressure of 1.5 x Class Rating of valve. I believe the previous ASME code was previously 1.5 x design pressure which is much lower. For example if I have a valve taking say 160 bar the previous hydrostatic test pressure was 240 bar. Under the new...
jmarkus,
If it is a revision some change must have been made to the drawing whether it be a dimension or a note. The easiest method is to place the modification symbol (I have previously seen it as an inverted triangle with a letter in it)next to the dimension or note that has changed.
If...
I am trying to track down a German crane manufacturer called "Maertens". This trade name is on an old crane so it's likely that they have probably been taken over by someone else or gone out of business. I have done the usual intnet searches and haven't been able to come up with any...
Speedcore,
Although not a program a good place to start on the does and don't of piping design take a look at:
http://www.nts.no/norsok/p/p00104/p00104.htm
Also for friction losses:
http://www.monachos.gr/greek/calculators/Darcy_weisbach.htm
Cheers
gb
Knsar,
ksnar,
My apologies I made a mistake in my earlier calculations and therefore the numbers are incorrect. I calculated an incorrect slip factor
Using
Torque = F x Slip Factor (usually 0.25 for s.s on s.s)x D
Therefore F = 25KN and Pressure = 138MPa.
Hope this closes this out.
gjb
ksnar,
I have used all the information given, applied it to the formulas given and it works out you are that you require approx 275Mpa of resistant force to hold the 75Nm torque hence the deformation in the Al plate. However the 0.2 friction co-efficient appears optimistic as it's likely to be...
Vonlueke/Austim,,
The aluminium was described as soft hance my conservatism using a value of 172MPa (25KSI).
Point regarding friction is valid . However, I was pointing out that the equation given takes no account of friction (ie simple approach).
If you need to take friction into account...
Ksnar,
Here goes :-
Using Stress = Load /Area were Load = surface pressure
You need to limit the load to below that which the material yields (Aluminium approx = 172 MN/mm2)
To turn torque into load use (neglecting friction)
Torque = Load x pitch of screwthread/6.2832 (use SI units ie N &...
It sounds like either your manufacturers are making the goods incorrectly or your designs are adequate.
If a dimension is critical it should be toleranced as so. One such method of doing this above that of general tolerancing is geometric tolerancing.
Take a look through BS308 if you require...