The Steamboating Forum

This has been one of the warmest seasons ever, but it is time to layup the steam plant against he winter freezing conditions.

I began by removing all boiler connections to the feedwater system, draining all the piping, and applying a high vacuum pump to the boiler. The very low pressures produced by the vacuum pump lowers the boiling point of water to less than 60F (15C) and the boiler steams until all water is removed (evaporated). In the food processing industry this is called "vacuum drying", and it allows drying the boiler without the use of a fire.

For the feedwater system, I put "RV Antifreeze" into the feed tank and worked all the pumps until the prolelyne glycol came thru the pump discharge lines, good to -40F (-40C) without freezing.

Tomorrow I will run the engine with the vacuum pump (connected to the exhaust piping) until all water is gone

Then to wait until the spring season.

Just how much vacuum are we talking about? And -next question -where does one get such an item? Have you noticed ,Fred, that you walk to the tune of a different drummer? Paddle wheels and vacuum pumps-I mean really!! LOL Keep up the good work Fred and have a healthy New Year! Den

Thanks for the compliment! And very best wishes for your new year too.

The vacuum pump I am using is an ordinary Air Conditioning Service Pump, capable of 75 microns, or 0.0001 atmospheres, 0.00147 PSIA. To get water to boil at 59F (15C) you need to lower the absolute pressure to 0.25 PSIA, which is about 170X more than the maximum vacuum capability of this pump. This type of vacuum pump, with typical plug-in motor drive costs about $100 USD.

I attach a small baby food jar, with tube connection to the boiler, and the vacuum pump to another boiler connection, then turn on the vacuum pump. When I can see the water inside the jar boiling, I know everything is working. After a short time the water in the jar is gone, and so is all the wetness within the boiler, so long as the boiler metal is at a slightly higher temperature than the jar. The jar actually gets cold during this process, which I do in my workshop which is heated to about 70F.