How do they keep water from freezing in snowmaking pipes?

[billski]

When it's not running, which seems to be often. Is it drained back out?

 

[Greg]

Blankets. Duh...

 

[thetrailboss]

They drain the water out by either gravity (open a release valve) or by blowing air through them.

 

[Rambo]

They drain the water out by either gravity (open a release valve) or by blowing air through them.

I heard, one time, that somtimes they will pump some oil up through the water pipes after they gravity drain the water out. Probably not enviro friendly pumping a little oil out like that, if it is true.

 

[SkiFanE]

If the pipe is under pressure, I think that prevents it from freezing. But if the mt. needs pressure elsewhere, they need to drain it.

 

[billski]

I heard, one time, that somtimes they will pump some oil up through the water pipes after they gravity drain the water out. Probably not enviro friendly pumping a little oil out like that, if it is true.

I can't imagine them doing that; not only would that be expensive and a toxic issue to contain, but once you restart it, I'm sure you would have oil residue out on the mountain, something the EPA would just love!

Blankets. Duh...

I love scientific answers!

They drain the water out by either gravity (open a release valve) or by blowing air through them.

Ah-ha. The voice of reason. Thanks!

 

[KD7000]

If the pipe is under pressure, I think that prevents it from freezing.

No, pressure makes no difference if the water isn't moving.

If the water is flowing through the pipes under sufficient pressure, it generally won't freeze until it exits the pipe.

 

[threecy]

I heard, one time, that somtimes they will pump some oil up through the water pipes after they gravity drain the water out. Probably not enviro friendly pumping a little oil out like that, if it is true.

Never heard of that before...are you sure you're not confusing that with some mountains running water through pipes purchased from oil fields for the first time? Pumping oil through the system would be expensive and harmful to the snowguns.

Pressure is kept in the lines during operation. For shutdown, the return valves are opened all the way up to all for quick draining.

 

[SIKSKIER]

Freeze up at Cannon

Not sure what the scewed up at Cannon but I noticed they didn't start making snow till Thursday.On Saturday I was told they froze the line that went up Middle Cannon.After riding the detach you could clearly see where they had to use pick axes to chop the ice/snow around the pipe for twenty feet or so.It appeared they cut out a 2 foot section and rewelded it only because I saw a 2 ft piece laying there.Not sure it was a screw up that froze the pipe and made it split or just a freeze up.

 

[dbking]

I don't think that they run oil with the water. I DO remember that they mix oil with the air. Back in the 80's Sugarbush had an explosion near the base area because of it. Too many parties ago to remember the details.

 

[thetrailboss]

Not sure what the scewed up at Cannon but I noticed they didn't start making snow till Thursday.On Saturday I was told they froze the line that went up Middle Cannon.After riding the detach you could clearly see where they had to use pick axes to chop the ice/snow around the pipe for twenty feet or so.It appeared they cut out a 2 foot section and rewelded it only because I saw a 2 ft piece laying there.Not sure it was a screw up that froze the pipe and made it split or just a freeze up.

That's not the first time they have done that. They had some problems a few years back that forced them to abandon snowmaking for the rest of the season IIRC.

 

[skiberg]

That's not the first time they have done that. They had some problems a few years back that forced them to abandon snowmaking for the rest of the season IIRC.

I believe this is there third major rupture this year

 

[thetrailboss]

i believe this is there third major rupture this year

yikes!

 

[BushMogulMaster]

I don't think that they run oil with the water. I DO remember that they mix oil with the air. Back in the 80's Sugarbush had an explosion near the base area because of it. Too many parties ago to remember the details.

Oil is never intentionally mixed with air or water. In previous times, rotary screw compressors were common in a snowmaking setting. These required lots of oil, and always ran hot. The oil would find its way through the air lines in small quantities. For that reason, and because their high running temp means warmer air, most areas have nixed rotary screw compressors in favor of cleaner, cooler centrifugal compressors.



Regarding the original question: you drain the system. No water = no freeze! :wink: This is why you hear of a ski area "charging" the system when they are starting or restarting snowmaking. They have to charge the lines to get the water to wherever it's going. Sometimes that can be a multi-hour process. IIRC, it takes Breckenridge over 30 hours to charge a particular line that's very far from the water source.

Unfortunately, though, freezing does occur from time to time. And it's no fun. One way to prevent that is to keep all of your water lines buried a few feet for insulation. Above ground pipe is much more likely to freeze, and it can even happen (albeit rarely) with water flowing, believe it or not.

 

[gmcunni]

Blankets. Duh...

i was going with hot water.

 

[mondeo]

If the pipe is under pressure, I think that prevents it from freezing. But if the mt. needs pressure elsewhere, they need to drain it.

No, pressure makes no difference if the water isn't moving.

If the water is flowing through the pipes under sufficient pressure, it generally won't freeze until it exits the pipe.

Pressure doesn't make a significant* difference, moving or not. When it is moving, it's purely a question of moving quickly enough so that it doesn't cool to 32°F before it hits the nozzles. Sometimes it does freeze. See Lower Superstar in December for an example.

*-There is a very small decrease in melting point with increasing pressure, but would be negligible with the pressures in snowmaking systems.

 

[bobbutts]

Pressure doesn't make a significant* difference, moving or not. When it is moving, it's purely a question of moving quickly enough so that it doesn't cool to 32°F before it hits the nozzles. Sometimes it does freeze. See Lower Superstar in December for an example.

*-There is a very small decrease in melting point with increasing pressure, but would be negligible with the pressures in snowmaking systems.

With movement the water can be below 32 and remain liquid.

 

[mondeo]

With movement the water can be below 32 and remain liquid.

Nope, supercooling only happens when water is still, or very smoothly flowing. If there is turbulence, the shearing action will seed crystallization and a solid-liquid mixture will result, exactly at the freezing point.

 

[Stache]

Nope, supercooling only happens when water is still, or very smoothly flowing. If there is turbulence, the shearing action will seed crystallization and a solid-liquid mixture will result, exactly at the freezing point.

Isn't that how 7-11 makes Slurpees??????

 

[billski]

Isn't that how 7-11 makes Slurpees??????

Naw... They just have some minimum wage employee go to the parking lot and scrape up some snow.
:dunce: