Fuel tank and water tank level sensor (very long)

[BartW]

I would like to place indicators for Fuel-, fresh water-, white tank- and black tank- levels,
The tanks for Fuel and fresh water are 150cm high,
What kind of transducer can I use for these ?

the two other tanks are more "normal" size, so different options available

 

[vas]

Bart,
there were a few options listed as replies on my MiToS helm design thread in Feb.

IIRC, the result is that it's a bit ott to have a lever based thing for such sizes. There is a system that you can order to size, someone posted in that thread. I did ask my BMS guys and coming from homeautomation systems, there are two unconvetional options that can also be used.

Echo sounder tech but it's a bit expensive and could be slightly annoying with a tick that can be audible on each system check, and I was told that this is every 5-10secs and obviously depends on where is the tank and how the space is organised. Excellent for black water tanks as the sensor doesn't touch the stuff...

There are also pressure sensors that can be calibrated for large diesel/fresh water tanks (obviously not for black /grey water tanks!) I think I'll be going for this solution as it's v.accurate and dead simple, no need to drill large inspection holes and have the necessary clearance in order to fit various types of floaters. Just a tee off the liquid exit and the sensor bolts one, job done.
Leaving BRU in a couple of hours, will search my files and come back to you tomorrow.


V.

 

[BartW]

Leaving BRU in a couple of hours

our flights will cross then, me coming from Rome

rgds Bart

 

[Bandit]

I have a tenk tender system , I have fitted these on three boats now they are very accurate when calibrated , very simple and robust.

http://www.thetanktender.com/

 

[aquatom]

How about this system

http://www.vetus-shop.com/vetus-display-for-tank-level-indication-p-1241.html

I know it works with many sensors including the Vetus ultrasonic sensors. You can't hear the clicking unless you put your ear directly to the tank

 

[vas]

our flights will cross then, me coming from Rome

rgds Bart

off topic:

Dear Luftwaffe cocked it up big time, first flight cancelled, second was overbooked, third flight with Swiss ended up arriving in Athens at 23:30, from an original 18:00
Finally left BRU at 17:00 and I think your flight arrived at 17:30, so missed you for half an hour Next time we'll manage it better.

V.

 

[KevB]

You could try asking tek-tanks
Realy helpful company.

 

[BartW]

thank you all for the sugestions !
much apreciated,

might go for the ultrasonic sensors from Tek Tank or Vetus,
only concern is internal partitions in the way,
hammering on the tank wall might show,
have to drill a inspection hole to find out or to be shure
hopefully just one in each tank

 

[Pennpromo]

Tank Senders

I have to say that I have always found the best senders to be mechanical ones. Wema do a really good range and also Offshore Systems. Wema senders are analogue and have a nylon float that rises up a stainless pole. Offshore's are digita,l NMEA 2000 compliant, and are based, I think, on resistance between two "prongs", with no moving parts. Theirs are self calibrating, made in stainless and have no parts to go wrong. Coincidently we fit both to the tanks that we make at The Tank Company/ Oval but other than that I have no connection to either company.
When we have tried some of these ones that "ping" the tank they are quite hard to set up to get a linear output, they do read but it tends to be a little erratic. Offshore quote something like +/- 0.5%, they also do an averaging module so if you have a big tank you can fit two and it then they allow for any level change in the boat.

 

[Trundlebug]

You could also try these people
http://mcsboatproducts.co.uk/portfolio/waste-water-gauge/

Not the best website but the products themselves are OK.
No moving parts, and relatively low cost compared to some. It measures pressure of liquid above the sensor and they do an offshore version with stainless sensor (ignore the "inland waterways" claim on the website)

They're all made to measure, just specify depth of tank at time of ordering and they make the tube length to suit.

The small digital gauges are quite smart although the analogue ones look a bit dated.

Worth considering

 

[BartW]

I have to say that I have always found the best senders to be mechanical ones. Wema do a really good range and also Offshore Systems. Wema senders are analogue and have a nylon float that rises up a stainless pole. Offshore's are digita,l NMEA 2000 compliant, and are based, I think, on resistance between two "prongs", with no moving parts. Theirs are self calibrating, made in stainless and have no parts to go wrong. Coincidently we fit both to the tanks that we make at The Tank Company/ Oval but other than that I have no connection to either company.
When we have tried some of these ones that "ping" the tank they are quite hard to set up to get a linear output, they do read but it tends to be a little erratic. Offshore quote something like +/- 0.5%, they also do an averaging module so if you have a big tank you can fit two and it then they allow for any level change in the boat.

even if I find mechanical senders that are long enogh (1,5m) I doubt very much that I can get them in the tanks , no room above the tanks...

On my Karnic, I have sonar sensors, and agree that they sometimes react strange, but on average, I can use them,

 

[BartW]

You could also try these people
http://mcsboatproducts.co.uk/portfolio/waste-water-gauge/

Not the best website but the products themselves are OK.
No moving parts, and relatively low cost compared to some. It measures pressure of liquid above the sensor and they do an offshore version with stainless sensor (ignore the "inland waterways" claim on the website)

They're all made to measure, just specify depth of tank at time of ordering and they make the tube length to suit.

The small digital gauges are quite smart although the analogue ones look a bit dated.

Worth considering

thats interesting !
the old fashion meter display's are a bit in tone with the age of the boat
what do you mean by tube length,
I assume they work with a electric wire connection between sensor and display

not like the model previously posted, that works with pressure tubes,
which is unusable in my setup distance too long between tanks and display.

 

[Trundlebug]

thats interesting !
the old fashion meter display's are a bit in tone with the age of the boat
what do you mean by tube length,
I assume they work with a electric wire connection between sensor and display

not like the model previously posted, that works with pressure tubes,
which is unusable in my setup distance too long between tanks and display.

The sensor is a pressure sensor pre-fixed into the bottom of a plastic tube, made 10% shorter than the depth of the tank (to your specification).
Wires go up through the tube to the head unit, then you connect up the head unit to the display (3-4 wires from memory).

To fit the sensor you'll need clear vertical access above the tank to insert the tube, hole size req'd was 32mm / 1.25in I think.

They do 2 types of tank seal. Either a BSP fitting or as my holding tank was GRP built into the boat, a rubber grommet type seal, fit and forget.

Easy to fit, neat looking, simple, low cost and no moving parts were all the features I was looking for.
I have always been a bit concerned about other waste holding tank sensors with moving floats, described as "very easy to clean" Er, no thanks!!

 

[BartW]

The sensor is a pressure sensor pre-fixed into the bottom of a plastic tube, made 10% shorter than the depth of the tank (to your specification).
Wires go up through the tube to the head unit, then you connect up the head unit to the display (3-4 wires from memory).

To fit the sensor you'll need clear vertical access above the tank to insert the tube, hole size req'd was 32mm / 1.25in I think.

They do 2 types of tank seal. Either a BSP fitting or as my holding tank was GRP built into the boat, a rubber grommet type seal, fit and forget.

Easy to fit, neat looking, simple, low cost and no moving parts were all the features I was looking for.
I have always been a bit concerned about other waste holding tank sensors with moving floats, described as "very easy to clean" Er, no thanks!!

ok, now I understand,
what material is the tube made from ?
I assume it is solid, not a flexible hose,
problem is I have not much clearance above the fuel tanks

I understood that the pressure sensor could be placed on a T connection on a fuel outlet, on the bottom of the tank ?
I'll call them with my questions,
thanks for the advice

rgds Bart

 

[vas]

ok, now I understand,
what material is the tube made from ?
I assume it is solid, not a flexible hose,
problem is I have not much clearance above the fuel tanks

I understood that the pressure sensor could be placed on a T connection on a fuel outlet, on the bottom of the tank ?
I'll call them with my questions,
thanks for the advice

rgds Bart

T connection and sensor is good for fuel and clean water-that's what I'll do.

Waste water is a no no as it will block (I guess very soon)
For the dirt and smell involved, I'd go for a ultrasound one on top of the tank, no need to touch anything and to be peferctly honest, it's not so critical to know exactly when the holding tank is full, just make sure you empty it beforehand...

V.

 

[Trundlebug]

Waste water is a no no as it will block (I guess very soon)


V.

NO There are no moving parts, nothing to block, that's the whole point and why it is perfect for waste water.
It merely measures the pressure of liquid above the sensor

The plastic tube is semi rigid, similar to plastic water pipe. It has some movement in it but not floppy like flexible hose

 

[Bandit]

The Tank Tender system I suggested works in the same way it is a capilliary tube that wont block or cross contaminate from different tanks except tank tender is a pressure gauge with no electrical supply or electronics and very accurate.

 

[vas]

NO There are no moving parts, nothing to block, that's the whole point and why it is perfect for waste water.
It merely measures the pressure of liquid above the sensor

The plastic tube is semi rigid, similar to plastic water pipe. It has some movement in it but not floppy like flexible hose

sorry if it wasn't clear, I was talking about the T off the bottom of the tank approach with the sensor on the T. That is indeed a no no. Not the solution you're proposing.

cheers

V.

 

[BartW]

The Tank Tender system I suggested works in the same way it is a capilliary tube that wont block or cross contaminate from different tanks except tank tender is a pressure gauge with no electrical supply or electronics and very accurate.

thanks for the explanations and the sugestion Bandid,
in my case, problem with this system is the distance between the tanks and the central electric panel where I want to fit the gauches.
(central position on the boat)
some time back I have pulled a multicable ao for these indicators, from the panel to the engineroom (a long and difficult route)
so pulling these tubes is very difficult,and potential risk for bending the tubes.

So I'll probably go for ultrasonic sensors, found a good source for them...
thanks for posting