my idea about boiler water feed

[lfkui]

normal we use pump to feed water to boiler.

Last night, I thaught an idea of water feed plan: using compress air. one compress air vessel, one feed water vessl, the volume of the former is twice of the later. pipe connect these two vessel, and there is one electromagnetic valve arrangedbetween these two vessels, this valve is control by boiler water level gauge sensor. The pressure of compress air is two time of boiler working pressure, when boiler water is low, the sensor will open the electo magnetic valve, compress air will go to feed water vessel, then the pressure of feed water vessel will increase, when its pressure above the boiler pressure, the check valve will open, and water feed into boiler. While the boiler water level is ok, the electromagnetic valve will close, the pressure of feed water vessel and boiler are same, the check valve will close. one time water feed cycle will be finish.

because my poor English, maybe you not get what I write.

 

[Herbiev]

Hi Ifkui. Sounds like a great idea especially if the solenoid is operated by electricity from a generator driven by the engine

 

[Jasonb]

normal we use pump to feed water to boiler.

We also use injectors quite a lot, infact a lot of larger model engines don't have a pump, just two injectors. These use steam from the boiler to feed water into the boiler and unlike your compressed air will not run out. They work by passing the steam through what are termed "cones" which creater a venturi effect and allow the steam to push the water against boiler pressure.

J

 

[lfkui]

We also use injectors quite a lot, infact a lot of larger model engines don't have a pump, just two injectors. These use steam from the boiler to feed water into the boiler and unlike your compressed air will not run out. They work by passing the steam through what are termed "cones" which creater a venturi effect and allow the steam to push the water against boiler pressure.

J

I heard injector, but I just know it is for feed boiler water. Would you post some pictures of inectors.

 

[picclock]

Also very interested to see the Venturi effect injector. But as a possibility how about having the water feed tank above the boiler pressurised with steam feed. Then you only need the valve and gravity would do the rest. Kind of like a tank engine but with the tank bottom above the boiler water level.

Best Regards

picclock

 

[rkepler]

Also very interested to see the Venturi effect injector. But as a possibility how about having the water feed tank above the boiler pressurised with steam feed. Then you only need the valve and gravity would do the rest. Kind of like a tank engine but with the tank bottom above the boiler water level.

The problem with that is that the steam would condense on entering the tank until the tank temperature matched that of the steam. At that point the feed tank would simply be an extension of the boiler.

Here's a link to the Wikipedia page on injectors: https://secure.wikimedia.org/wikipedia/en/wiki/Injector

Injectors are very reliable ways of getting water into a boiler, but not as efficient as a steam operated pump normally will be.

 

[MachineTom]

The issue you would have with controlling water volume based on letting HP air into the water tank, would be that there would be no real cutoff of the volume delivered.

The boiler control says more water, the solenoid opens, an unknown amount of air rushes into the water tank, pressure rises in water tank, begins to flow water into boiler, level goes up, control shuts off air flow, trapped air in water tank is at pressure greater than boiler, water will continue to flow until pressure in boiler and water tank equalize, which may not happen until the boiler is water locked. How to refill the water tank, blow off all that air? while running? boiler needs water? no pressure available?... Just a thought

 

[picclock]

@ machine tom
Solenoid valve in water feed to boiler. Heat in water feed tank minimal as no steam flow until solenoid valve open. Then only low volume of steam approx equal to volume of water.

If refilling required during operation, could isolate steam feed to tank, disable solenoid, blow off pressure in water tank, fill tank, enable pressure feed to tank and enable solenoid.

It was just an off the cuff idea - I've never built a steam engine.

The venturi info was interesting. Although I understand the principles well enough, to get a pressure drop of that magnitude must require an extremely high steam flow rate. Live and learn :bow:.

Another approach might be to use a sealed rotating cylinder with openings at either end set up like a rotary valve. Water at atmospheric pressure could be gravity fed into the top of the cylinder. As the cylinder rotated the top would become sealed and a hole uncovered at the bottom. The water would run out of the cylinder into the boiler and be replaced with steam. Further rotation would allow the steam to vent from the top then water would once again fill the cylinder. The energy requirement to operate this type of mechanism is only that needed to overcome the seal friction. As an additional thought, if the cylinder was housed in the water feed tank the steam would condense and the water would be sucked into the cylinder, also adding a tiny amount of heat to the feed water, so only two seals this way.

I really must get into this when I get the time - the more I think about it the more interesting it becomes.

Best Regards

picclock

 

[Noitoen]

Here is a video about the injector (sorry it's in Portuguese) [ame=http://youtu.be/m2u3kivLDL0]http://youtu.be/m2u3kivLDL0[/ame]