LS,
On a pcb near the 230 VAC connections, there are 3 varistors towards the switching power supply (for 24 VDC and 5 VDC).
Q1: Why are there 3 varistors (between PE and neutral, PE and live, live and neutral), instead of 1 between live and neutral?
The pcb is fed by an isolated power supply...
Thanks Chief for your reply. I am aware of pulsations in a fuel system, but problem for this specific case is that it only occurs during slow steaming. Could a retaining valve behind the engine cause this, if it comes in resonance with pulsations of the fuel pumps, which is then not happening at...
I think you need a real-time laboratory. Depending on how you define quality, you need to do various types of measurements. Biggest challenges lie in added chemicals / unwanted substances, that you will only find if you know what you need to look for. Of course it will be possible to measure...
LS,
A superintendant informed me about the fact that slow steaming could cause heavy pressure pulsations in a ships fuel system. Can someone explain why this happens / what causes this phenomenon? Is there someone who has experience with this, and may be also in combination with a large...
Thanks for your replies.
The fluid viscosity is in the range of 12 mPas, with a density of approx 0,94 kg/l. Piping diameter is a DN50 steel pipe (exact material specs are not known). The frequencies of the pulsations are depending on the point of operation and are between 1 Hz and 10 Hz.
We...
@ BigInch
Pressure pulsations are caused by a piston pump. As customer does not want to take precautions, we can just warn him. At least I want to make a calculation for our delivered equipment. With normal flow, I can use Darcy-Weisbach to make a pressure drop calculation, but this will not...
LS,
If a piping system for the transport of oil is suffering from pressure pulsations, how can the effect further in the piping be calculated.
Pressure is approx 4 bar, and pressure peeks up to 25 bar (in miliseconds). What will the effect on the pressure be 50 metres further in the piping...
Thanks for your reply, and I indeed meant the high pressure (circulation) part of the fuel system. Do you mean engine or booster module manufacturers? I have contacted both parts, but in the moment neither of them seems to have an answer (or does not want to give an answer).
Class (GL/LR)...
LS,
What kind of pressure pulsations can be expected in a ships heavy fuel oil supply system (amplitude and frequency). And are there any regulations from classification agencies concerning these pulsations. (I have searched in GL rules, but haven't found them so far).
Thanks.
DYV
Is there a way to calculate the pressure drop over a basket strainer. I know that suppliers can, but I want to do some calculations in advance in Excel or something.
I assume that based on flow, viscosity, filter area and mesh widt, this should be possible. Fluids are heavy fuel oils (newtonian...
With stiffness I mean the stifness of the overall part. But due to the fact that EPS does not give any stiffness, this should come from the top coating. In the EPS also some (electronic) components are integrated, which need to be covered with a coating for protection and also for the look...
Over design will always create a larger surface. But make sure that this area will in series (extra pass) or longer plate / pipes. You will have the same shear and thus reduce the risk of increased fouling. Adding more plates in parallel for a PHE will make that the PHE will foul more easily and...
Thanks Berkshire, I have found some on the internet. Both epoxy with chopped fibres and even polyurea with chopped fibres.
I will contact the supplier and see what comes out.
The production rate is not very high: lets say approx 5 m2 per week. But reducing man hours is important, so using a...
