Post by thread:[OT]:Material that floats in water, yet withstands

There is an industrial water boiler, with a pump that is switched manually to maintain water inside between two levels. The temperature of the water inside the boiler is maintained close to the boiling point. There is a transparent glass tube (about 1cm in diameter) that is hydraulically coupled to the boiler, to give a visual indication of the water level. This indication is used by an operator to switch the pump manually, at present. Now, I am trying to design a simple optical arrangement to detect the minimum and maximum levels, which would drive the PIC, and the software within to switch the pump at appropriate times. The problem is, what material can I possibly use that would float in water, and yet withstand very high temperatures on a long term basis? I could just drop a pellet of the stuff in the indicator tube, and then mount the minimum / maximum IR sensors on the tube externally, if I find the right material. Thanks and regards, Anand Dhuru -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Pumice would answer that requirement, as would a brass float (heck depedning upon the diameter of the tube you could use a cartridge case with the base down.. providing it couldn't tip over in the tube, there would be no need to seal the top. Des >>> spam_OUTardhuruTakeThisOuTVSNL.COM 18/05/03 11:59:26 pm >>> There is an industrial water boiler, with a pump that is switched manually to maintain water inside between two levels. The temperature of the water inside the boiler is maintained close to the boiling point. There is a transparent glass tube (about 1cm in diameter) that is hydraulically coupled to the boiler, to give a visual indication of the water level. This indication is used by an operator to switch the pump manually, at present. Now, I am trying to design a simple optical arrangement to detect the minimum and maximum levels, which would drive the PIC, and the software within to switch the pump at appropriate times. The problem is, what material can I possibly use that would float in water, and yet withstand very high temperatures on a long term basis? I could just drop a pellet of the stuff in the indicator tube, and then mount the minimum / maximum IR sensors on the tube externally, if I find the right material. Thanks and regards, Anand Dhuru -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics ________________________________________________________________________ This email has been scanned for viruses by the CITEC Email Anti-Virus service powered by MessageLabs. For more information on a proactive email anti-virus service working around the clock, around the globe, visit http://www.citec.com.au ________________________________________________________________________ ________________________________________________________________________ This email has been scanned for viruses by the CITEC Email Anti-Virus service powered by MessageLabs. For more information on a proactive email anti-virus service working around the clock, around the globe, visit http://www.citec.com.au ________________________________________________________________________ -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Slight digression here, but can anyone tell me if this is the first message in this thread? It's starts off with "Re:", but it's the first I've received, and the text sounds like the start of a message. I've had this same concern for a few other messages lately, so it's time to worry, and check if I'm losing messages anywhere. Thanks, -Neil. On Sunday 18 May 2003 08:59, Anand Dhuru scribbled: {Quote hidden}> There is an industrial water boiler, with a pump that is switched manually > to maintain water inside between two levels. The temperature of the water > inside the boiler is maintained close to the boiling point. > > There is a transparent glass tube (about 1cm in diameter) that is > hydraulically coupled to the boiler, to give a visual indication of the > water level. This indication is used by an operator to switch the pump > manually, at present. > > Now, I am trying to design a simple optical arrangement to detect the > minimum and maximum levels, which would drive the PIC, and the software > within to switch the pump at appropriate times. > > The problem is, what material can I possibly use that would float in water, > and yet withstand very high temperatures on a long term basis? I could just > drop a pellet of the stuff in the indicator tube, and then mount the > minimum / maximum IR sensors on the tube externally, if I find the right > material. > > Thanks and regards, > > Anand Dhuru -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

The problem becomes a lot easier if you can attach a larger tube alongside the sight glass for a more reasonable sized float. Boiling water is not that hot, even a toilet tank mechanism might be adapted to the task. Sometimes low tech is a better solution... John Ferrell 6241 Phillippi Rd Julian NC 27283 Phone: (336)685-9606 .....johnferrellKILLspam@spam@earthlink.net Dixie Competition Products NSRCA 479 AMA 4190 W8CCW "My Competition is Not My Enemy" {Original Message removed}