Hybrid Ballast Tank/Piston System

[trout]

Ideally I wanted to have everything inside the WTC and was fighting with this for almost a week until I finally lost that argument with myself and placed them where they are now. This may change again as this is an WIP experiment.

LOL, don't I know the wrestling and modifications as you work out the details! Heck, that is almost my motto.

[Bob Gato]

I see-very narrow sensing area with the laser as opposed to the sonic sensor's cone. Thanks for sharing this...Great Link!

[Monahan Steam Models]

It will not increase the internal pressure much at all. I am wondering if the nibble end should be facing inside, but if you are using the laser distancing, then I understand why you have it the way you do. Will be watching this one.

Ideally I wanted to have everything inside the WTC and was fighting with this for almost a week until I finally lost that argument with myself and placed them where they are now. This may change again as this is an WIP experiment.

[Monahan Steam Models]

Short answer is yes but from researching the different types of distance sensors it seemed in this application the laser sensors provided the best results.

Here is the sensors I use: https://www.adafruit.com/product/3316

[trout]

It will not increase the internal pressure much at all. I am wondering if the nibble end should be facing inside, but if you are using the laser distancing, then I understand why you have it the way you do. Will be watching this one.

[Bob Gato]

Just asking-but could someone use those sonic proximity sensors that come with an arduino experimenter's kit?

[Monahan Steam Models]

Nice touch on the optical piston sensors! A new possibility has been added and could work (maybe not necessary in this application) thru water from inside the dry area.

Bob,

Thanks! But I can not take any credit for the optical piston sensors. I learned that one from the work John Dutton did with his twin jack screw driven piston tanks. They read the backside or dry side of the piston. The sensors work really well and are extremely accurate. Eliminates the need for micro switches which is very nice.

Nick

[Monahan Steam Models]

I am assuming you will be pumping water? or are you pumping air and making changes that way? I ask because would you use the nipple end of the syringe to connect to the pumps?

Tom,

You are correct that I would be pumping water with the peristaltic pumps and the connection would be to the twist lock nipple end of the syringe. At 11.1 volts the peristaltic pump will fill/move the piston from 0ml to 100ml in 22 seconds. I’m guessing that small trim pistons like these won’t raise the internal pressures to high in the WTC.

Nick

[Bob Gato]

Nice touch on the optical piston sensors! A new possibility has been added and could work (maybe not necessary in this application) thru water from inside the dry area.

[trout]

I am assuming you will be pumping water? or are you pumping air and making changes that way? I ask because would you use the nipple end of the syringe to connect to the pumps?

[Monahan Steam Models]

Aiming for static pitch control?

Yes Sir. That and I mainly want to explore what is possible using a system like this and Arduino.


Two jack screw driven piston tanks was the original goal but the packaging of all the components in a 17” long WTC upon initial review, looked like that wasn’t going to happen. So I thought I might explore the syringe and peristaltic pump idea for fun. Main ballast tank will only have two states. Completely flooded or completely empty. If the piston trim system fails the main tank can be blown to get the boat back to the surface. The overall piston tank capacity is more than what is needed for trimming. Total ballast with 10% added is 850ml. Ballast capacity was subtracted from the main tank and added to the pistons to make more room available in the WTC.

[redboat219]

Aiming for static pitch control?

[Monahan Steam Models]

The past few days have been spent in the early design stages of a hybrid ballast system that uses a central vent/blow ballast tank with two smaller piston type trim tanks at either end of the WTC.



This is what I have so far. Still lots of bits and pieces to add to the design but the nuts and bolts of it are there. Central tank will operate as a S.A.S. System and will have two micro LPB. A gas backup will also be added.

The two awkwardly placed 100ml syringes placed on each of the WTC’s end caps will simply be a floating piston style. Each of these will have it’s own peristaltic pump to move water in or out. At the larger open end of the syringe will be a precision laser distance sensor that keep track of the floating piston’s length of stroke.

An Arduino Nano will be on board to help automate much of the dive routine and automatic trimming when switch into auto mode. Depth will be sensed by a precision pressure sensor also feeding back into the Arduino unit.