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...
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...
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...
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...
LS,
For creating a topcoat on an EPS250 part, we have experimented with hot spray polyurea. This material gave enough strength, but stiffness was to low. Product is round (diamters from 200 to 1000 mm), and the basic EPS is 40 mm. Application temperature is from 15°C to 55°C.
Now we are...
LS,
Another piping problem I have is as follows:
We do have a large pipe (DN200) in which a scoop (DN100)is placed in the middle of the flow, that reduces conically to DN50. This pipe goes out of the pipe and is by-passed for about 0,8 m. In the by-pass a measuring section is placed (and thus...
LS,
If a small cylinder is placed in a pipe, what will be the pressure drop.
The force acting on the cylinder will be:
F=Cw*A*0,5*rho*v^2
Flows are turbulent (Re>10000).
Should I use an energy approach?
Thanks DYV
LS,
We are applying a teflon coating (PTFE / FEP) to a stainless steel surface for its non-stick properties. Problem is that in some occasions the coating lets loose.
- Is there a method to test the bonding of the teflon coating to the stainless steel?
- Is there an alternative for teflon as...
LS,
We were confronted by a customer that IEC regulations (we don't have an answer about which one) require that distance between power earth (220 VAC) and signal earth (4-20 mA) should be at least 1 meter. Can somebody confirm that this regulation exists, or is there somewhere a...
LS,
For a calibration unit for positive displacement flowmeters for fluids, we are investigating the possibility of a piston or pipe prover. Does anyone have experience with these provers, and are there manufacturers of standard provers.
thanks,
DYV
LS,
To clamp a measuring device onto a round steel structure, the choice was made to used a kind of "knife". Since the contact area is very small, it is possible to exceed the yield stress of the metal (knife and structure are made from identical materials) and obtain a very stable...
LS,
In the input circuit of a measuring instrument also a diode bridge is placed (behind an opto-coupler). The input circuit is connected to another instrument with a voltage free contact. It is simply used to measure the frequency of the incoming pulses (between 1 and 10 Hz).
Why is a diode...
LS,
We have a system in which 2 fluids (A and B) are blended together. A is the main flow to which B is added with a control valve (pneumatic with positioner). The system runs without pump, but the driving force is gravity (tanks are 50 metres higher). As flow and pressure are fluctuating...
LS,
When applying a certain (stainless) steel, the modulus of elasticity, shear modulus and poisson's ratio can be found.
Can someone tell how accurate these figures are and what deviations can be expected. Are they e.g. within 5%? Should we have the materials tested every time to be accurate...
LS,
We have a small flowcomputer with a passive transistor output. The system to which it needs to be connected has a Namur-signal input. How can we connect this, or do we need some kind of signal converter/amplifier.
Thanks,
DYV
LS,
On board ships the HFO is circulated over the engine. What is the main reason for this circulation. Cooling, and if yes of what? Or for controlling?
Thanks,
DYV
LS,
When installing Exd equipment in a zone 1 area, are there any requirements for the connecting cables, when these cables will go through zone 0 area (E.g. armoured cables or??). It is equipment which will be installed on board of ships (tankers).
When using Exd equipment in combination with...
LS,
The viscosity of yeast in the brewing process depends on the concentration of the yeast and the shear rate (and of course temperature).
Can anyone help me with some experimental data (or formula) about the relation between these paramters.
thanks in advance,
DYV
LS,
For the design of an accurate clamp-on system, we are looking for measuring data of the roughness of propellor shafts. Does anyone know where these data (Rz = average peak-peak and distance between peaks) can be found? Or does someone have these data available?
Thanks,
DYV
