Raw Water Flow Sensor Question??

[rogerthebodger]

Don't forget we have to pay import duty.

Don't we all and we have to pay a higher postage from china than the UK even through we are closer to china that you are may be

 

[rogerthebodger]

In post 4 I said "I see from the data sheet that the alarm won't operate until the flow drops below 1.4 litres/min, which doesn't sound much at all. I'd have thought that a partial restriction in the cooling water could lead to overheating before the flow reduced to 1.4 litres/min."

How is that "criticism"? It's an honest observation, based on facts which I subsequently supplied when you asked for them.

I can't believe that anyone else would perceive this as criticism. If we follow your rules of never commenting on other people's recommendations, the forums will soon die. Is that what you want?

Whatever you say

 

[pvb]

Whatever you say

Not an intelligent reply, but less argumentative than you normally are. Maybe the message is getting through?

 

[goeasy123]

OP here. The reason I want to be able to sense water flow, or lack thereof, is that I can't otherwise see if water is flowing. I may find that the temperature is rising and I can see that on a guage, but I don't know why.

 

[PaulRainbow]

OP here. The reason I want to be able to sense water flow, or lack thereof, is that I can't otherwise see if water is flowing. I may find that the temperature is rising and I can see that on a guage, but I don't know why.

I would fit an exhaust temp alarm. If you want to see if the water is pumping, by all means fit a flow sensor, bu that has limitations. You can also fit a simple pee pipe to see if water is being pumped.

 

[pvb]

OP here. The reason I want to be able to sense water flow, or lack thereof, is that I can't otherwise see if water is flowing. I may find that the temperature is rising and I can see that on a guage, but I don't know why.

Isn't lack of coolant flow the most common reason for overheating?

 

[vas]

Another option is to fit a seawater pressure sender after the pump and before the first heat exchanger. I've done that on both main engines and genatator 2cyl yanmar 2gmf. Normal conditions is 0.3bar, setup a warning at 0.08, alls fine! HUBA sender is plastic bodied and cost 30euro each Iirc.
This way I get a high pressure when heat exchangers are clogged, and low pressure when there's an intake restriction or buggered impeller.
Catch is that all data goes to my custom NMEA2K boxes which do the processing and reporting on the bus...

V

 

[Cariadco]

I would like to know what kind of Engineer as the term Engineer is a very misused term.

Oh I dunno, maybe one who has a rudimentary appreciation of punctuation.....

 

[nshawdvm]

I like both methods as backu to each other. I wish the flow alarm would also give you an actual flow rate since then you could see when it starts to decrease before it alarms. Anyone know of a flow alarm that also gives an actual flow rate? Also, can you mount these vertically in the hose leading to the injection elbow? Aqualarm said yes but if actual flow is close to minimum it may trigger alarm earlier.
Last question is does anyone know what the actual flow would be on a Perkins 4.236m?
Thanks

 

[nshawdvm]

Another option is to fit a seawater pressure sender after the pump and before the first heat exchanger. I've done that on both main engines and genatator 2cyl yanmar 2gmf. Normal conditions is 0.3bar, setup a warning at 0.08, alls fine! HUBA sender is plastic bodied and cost 30euro each Iirc.
This way I get a high pressure when heat exchangers are clogged, and low pressure when there's an intake restriction or buggered impeller.
Catch is that all data goes to my custom NMEA2K boxes which do the processing and reporting on the bus...

V

Problem with that is if you get a clog at your intake strainer pressure will not increase so no alarm.

 

[PaulRainbow]

Problem with that is if you get a clog at your intake strainer pressure will not increase so no alarm.

Vas said "Normal conditions is 0.3bar, setup a warning at 0.08"

 

[Tintin]

I would like to know what kind of Engineer as the term Engineer is a very misused term.

Seems like you are one of the pedantic ones, whose solution is the only correct solution. Chill dude, life is hard enough without extra angst.

 

[rogerthebodger]

Seems like you are one of the pedantic ones, whose solution is the only corrw t solution. Chill dude, life is hard enough without extra angst.

as a retired Chartered Engineer also called Professional Engineers in other countries. who can be help personal accountable for their actions like if a structure falls down and kills someone a Chartered will be charged with culpable homicide as the captain of the costa concordia and the Engineer in charge of a building that fell down and killed several site workers a chartered Engineer needs to be pedantic to ensure his designs are safe and correct.

Also, as a Experienced Engineer I understand there are various ways of doing any job which are safe and correct and protect the users and workers

It's all about accountability for the work you do

 

[Tintin]

as a retired Chartered Engineer also called Professional Engineers in other countries. who can be help personal accountable for their actions like if a structure falls down and kills someone a Chartered will be charged with culpable homicide as the captain of the costa concordia and the Engineer in charge of a building that fell down and killed several site workers a chartered Engineer needs to be pedantic to ensure his designs are safe and correct.

Also, as a Experienced Engineer I understand there are various ways of doing any job which are safe and correct and protect the users and workers

It's all about accountability for the work you do

Wow. You really are so very important. We are simply not worthy. All hail.

 

[rogerthebodger]

Wow. You really are so very important. We are simply not worthy. All hail.

Far from it I know very well my knowledge and experience and what's more I understand my skill level

 

[Dockhead]

On my boat, at least -- yours may behave differently -- temperature of the exhaust elbow is a very good proxy for raw water flow, and it's a lot easier to measure.

If the elbow is cold then there's enough flow. If it starts to warm up, there is a problem. I have a thermocouple jubilee-clipped to my exhaust elbow, in thermally conductive paste. The temperature is displayed on my instrument panel, and there is a loud alarm if the temperature gets over 40 degrees.

Even a very small amount of seaweed in my strainer will produce a slight but visible temperature increase. Caveat is that the engine needs to be doing some work in order to produce hot exhaust.

This works well in my particular case. YMMV.

For my generator, I have an underbolt thermocouple under one cover bolt of my raw water pump. This is even more sensitive, as it does not require hot exhaust to show a flow problem.

 

[Refueler]

I have a water flow indicator on my Laser machine cooling system .... its based on a tube with a brightly coloured spinner inside it. No alarm ... just mounted where I can see it .....

Loads of them in different sizes on eBay / Ali-express etc.