A mechanically induced vacuum system that can be used to retrofit one-, two- pipe or mixed one-/two- pipe steam heating system.
Traditionally in steam systems the boiler would need to build just enough pressure to overcome the atmospheric pressure and force the air out through tiny holes in the steam air vents at the end of the steam mains (2-pipe system) or air vents on the radiators (1-pipe systems).
The air, that fills the piping and radiators, needs to be removed before the steam can move in to do its job, heating the living space. When steam pushed all the air from radiator and reached the vent, a pin sitting on top of a bellows expanded and closes the hole before the steam was allowed to escape.
With a vacuum pump, these air vents are no longer needed and are replaced with a vacuum lines in order to evenly evacuate air from the system and from each radiator. In the case with 2 pipe systems, the return piping can double as the vacuum lines.
Under vacuum the steam is being pulled into the system, instead of having to push its way through, you will be filling the radiators and heating your home faster.
When the system is completely filled with steam, the vacuum pump will shut off and the steam molecule will shrink 1,700 times its size back into water. This creates a naturally induced vacuum that will keep pulling steam from the boiler, long after the burner has shut off, steadily lowering the temperature in the system and keeping a balanced flow of heat moving towards the lowest point of pressure that is now the coldest rooms of the house.
By controlling the vacuum level, we can control the temperature of the steam in the radiators. With ball valves on the vacuum lines, we can control the path in which the air takes leaving the system.
Differently from traditional steam heating system retrofit into vacuum systems, vacuum pump is used mostly to ease boiler cold start. Once the steam starts working its way into the radiator it will compress the remaining air towards the vacuum lines, lowering the vacuum pressure and will then cause the vacuum switch to turn the pumps on, pulling the remaining air out of the system. If on a design day the boiler runs long enough to fill all of the radiators and the vacuum lines, a high limit switch will turn the pump off protecting it from incoming Steam.
Naturally induced vacuum do the most of the work to first push steam into radiators.
When weather is not cold, the thermostat set temperature is often achieved before positive pressure is formed in the system at lower radiators temperature. So, more comfort and no overheating is attained.
Immediate benefits of steam heating system retrofit include energy savings, better comfort, even heat distribution, quicker building heating from cold start, control of radiators temperature, soft comfortable heat supplied into radiators after end of heating cycle , no air hissing/hot condensate spitting from air vents, reduced water usage. Long time gains are: reduced corrosion, maintenance and flexibility to improve system further at your own pace.
Please, note that old steam boiler usually accumulate a layer of sediments working like additional seal on tiny holes at positive pressure. Under vacuum more leakage may develop when these sediments are pulled inside boiler by outside pressure.
Technology can be readily used to upgrade existing vacuum systems, reduce vacuum pump size and electrical load, eliminate steam steam traps on 2 pipe systems with orifices and balancing valves, simplify operation and schematic.
In new installations significant gains can be achieved via using plastic tubing and modern cast aluminum radiators, smaller piping and boilers with better designs more suited for this type of operation, with as many different styles of radiation. Fewer moving parts and points of failure, resulting in a longer lasting, more dependable heating system.
I've been working Dr. Igor Zhadanovsky on this technology for almost 2 years now. This is the 2nd system we have converted into a mechanically induced vacuum system with great success.
If you are in the Boston area with a central steam heating system, send me or @izhadano
a message and we would be happy to give you an estimate.
Thank you for reading