2022-09-24, 11:24 PM
I have been working on tank level monitors for my black water tank.
First try was a Maretron TL100 ultra-sonic. Is a through a sensor hole in the top style. It worked at first but after the face of the transducer gets covered in shit, it stops working. It also suffers from the problem that all sensors of this type have, they cannot measure close to the transducer face.
Tried various float switch sensors, they gum up. I have not tried any of the in tank capacitance sensors yet, but am concerned that coating on sensor would mess up the readings.
I cannot use any sensors that are external to the tank because the sides and bottom are not accessible.
The latest effort is a drop in level sensor: Oumefar TL-136 Liquid Level Transmitter Signal Output Detector 4-20mA Water Level Sensor for Signal Detection (Range 0-1 Meter) from Amazon.
I put a condom like cover over the sensing part of the transducer because the very thin foil like diaphragm in the end of the transducer is not made for the corrosive stuff in a black water tank. The inside of the condom was filled with fresh water to transfer the pressure to the internal sensor.
It failed after about two weeks. It may have been because the pump out system in my marina is very powerful and the sensor could not deal with the vacuum, really not sure why though.
Today I installed a 0-2 meter sensor, this time with a better condom arrangement, and I plan to go easier on the pump out.
I live aboard so it gets a good workout.
Boy am I glad I lost my sense of smell several years ago.
First try was a Maretron TL100 ultra-sonic. Is a through a sensor hole in the top style. It worked at first but after the face of the transducer gets covered in shit, it stops working. It also suffers from the problem that all sensors of this type have, they cannot measure close to the transducer face.
Tried various float switch sensors, they gum up. I have not tried any of the in tank capacitance sensors yet, but am concerned that coating on sensor would mess up the readings.
I cannot use any sensors that are external to the tank because the sides and bottom are not accessible.
The latest effort is a drop in level sensor: Oumefar TL-136 Liquid Level Transmitter Signal Output Detector 4-20mA Water Level Sensor for Signal Detection (Range 0-1 Meter) from Amazon.
I put a condom like cover over the sensing part of the transducer because the very thin foil like diaphragm in the end of the transducer is not made for the corrosive stuff in a black water tank. The inside of the condom was filled with fresh water to transfer the pressure to the internal sensor.
It failed after about two weeks. It may have been because the pump out system in my marina is very powerful and the sensor could not deal with the vacuum, really not sure why though.
Today I installed a 0-2 meter sensor, this time with a better condom arrangement, and I plan to go easier on the pump out.
I live aboard so it gets a good workout.
Boy am I glad I lost my sense of smell several years ago.