Freezing......

Last night was damn cold, about -5 C around here. I woke up suddenly when I remembered that I had left the engine (2 inch scale) without draining the boiler, back in mid October, after the last steaming session - in case I had another go. It is in a rented garage , separate from the apartment. Until we moved here this summer, the engine had been kept indoors so I didn't have to worry about freezing.

This morning I went to check. There was a little ice on the footplate under the level gauge, but the water in the glass was liquid and the glass was unbroken. I drained the boiler and the full quantity of water came out, so the boiler was OK. No sign of any ruptures in any pipes. The pump would not make a complete stroke, so there is ice in the pump, but no visible breaks, the plunger would have risen to take up the pressure. I tried to drain the tank but only drips came out, I suspect some ice in the outlet. I left the drain open.

I think I was both stupid and lucky. When things are warmer I will check the water piping carefully to look for any leaks, cracks etc on the suction and discharge of the pump.Those of you with larger engines are accustomed to having them in the garage so you know what has to be done in winter.

Take heed!

Paul

My Airedale likes to drink from the outside tap, it's frozen and she tries to drink and looks at me very puzzled.

It did thaw this afternoon but now we have snow on the North Downs in Kent,

Clive,

I understand that Kent generally has a reputation for copping severe weather but East and North, especially. My late wife had a farming uncle and aunt in Longfield. Many years ago her aunt phoned her sister here in Brighton and said that the wind blows across the fields and puts huge snowdrifts against one side of their farmhouse but on that occasion it was particularly bad - drift was up to the eaves, of a 2 storey building!

John

When i lived in the Rocky Mountains in the USA not far from the Canadian border, we had to leave all the taps in the house dripping overnight so the pipes did not freeze up -- inside the house! When it got down to 40 below zero, we had to up the flow rate to a very slow trickle overnight.

According to their local folklore, hot water will freeze faster than cold water so it was deemed essential to keep the hot tap at a very slow dribble overnight in that weather. Not sure of the thermodynamics behind the folklore, despite having studied it in relation to steam plant and refrigeration. Other than I know the rate of heat transfer is higher when the temperature differential is greater. So hot water will drop in temperature faster than cold water in the same ambient temperature. But surely once the hot water gets down to the lower temperature that cold water is, the rate of heat loss is the same?

Always mystified me, but the locals there know how to deal with the cold so I did not argue. Being of mostly Scandinavian descent it is almost in their genes. Like the Russians, they know all the cold tricks. Like putting large pans of cold water down in the cellar to stop your stored potatoes, onions and rutabagas from freezing overnight. The latent heat in the water given up to the air in the cellar is enough to stop the spuds freezing and being ruined. But again, the advice was to only use pans of cold water, never hot water because it reportedly freezes faster.

Still a mystery to me.

1947 was the year I remember, the river Medway froze over with 6" of ice being tidal it stayed where it was. It snowed on my birthday, Feb. 27th. and lasted 3 weeks. We had snow right up the front door, open door , a wall of snow.

I hate it now, too much work shovelling it off paths etc. Dog loves it! Clive

Clive,

Dodged the '47 snows, born 6months after they'd gone!

'Lucky' John.

BTW, yesterday it started in Brighton around 2pm and it's a bit more than icing sugar on a mince pie. Maybe an inch or two, just enough to change the overall appearance of the landscape. Large stuffed freezer and stock piled tins packets n general cupboard ingredients so no need to venture forth for food for a few days.

John

Pressure gauges don't like freezing weather very much... it's not difficult to remove it and store it somewhere warm.

1946 + 47 were bad, even bread was rationed which it hadn't been in the war, because we were now feeding X million Germans as the "Victors"

Even Kiev is only -1 this morning, positively tropical !

And they've put the UK coal generators on standby... lol

Thank goodness our great leaders destroyed our industrial base in Britain otherwise we would have needed lots of coal generators to meet demand

Edited By Ady1 on 12/12/2022 10:21:05

Hopper

When I did an aircraft course, many years ago now, I remember during the cabin conditioning and pressurisation phase of the course being told that a fluid (for that read air) will more readily give up heat the hotter it is, in the system on the particular aircraft that we were training on the cold air unit in the air system actually heated the cabin air before cooling it as this was actually more efficient at achieving a cooler temperature, bearing in mind that all the cabin pressurised air was taken from the compressor stage of the engines so was starting out 450 degrees C. It didn’t make sense to me then and still doesn’t. Dave W

To nudge gently back to the original topic.....an engine in the cold..

Nigel, about the pressure gauge, thank you for that tip. My pressure gauge is mounted with three weeny 10BA screws and is a fiddly job to remove, without dropping the screws, even more so to refit, in a cold dark garage. I will have to wait for the spring, then test it in situ before steaming up. Likewise the gauge glass which might be cracked at the base.

Paul

If your temperatures are only just dropping to 0C or maybe a degree or two below zero C overnight, can you not just wrap your engine in an old blanket or quilt etc to insulate it? (Add a hot water bottle if it really worries you??) It really is not that cold to freeze things solid. We only used to worry about such things in the US when it got down towards zero F, which is -17C. Anything higher than that was not regarded as any great cause for concern. (Mind you,, they were all Eskimos that lived there in the Rockies. They used to go camping in that kind of weather and loved it. Dig a tunnel into a snow bank and crawl in to keep "warm". I never did take up the invitation to join them!)

Or use the trick I mentioned above and put a large pan/s of water in the workshop near the engine so the latent heat of the large body of water being absorbed by the ambient air stops the air temperature from dropping below 1C. It works in root cellars from Minsk to Montana.

Edited By Hopper on 12/12/2022 11:46:34

Water barrels in the apple store used to be normal in the UK too,

WRT difficult to remove pressure gauges, do your boiler inspectors not remove for testing every year?

Hopper,

Yes you are right, I should have used a blanket, but didn't think of it. No point now, any freezing has already happened.

Bazyle,

I avoid removing the pressure gauge for testing by hooking up the test pump directly to the tail of the gauge, which stays attached on the cross plate. That's what I will do before the first steam up next year, in case it got damaged.

Paul

The other thing you could do is put the engine, in its blanket, down on the floor. The ground will stay warmer than the surrounding air. Meanwhile, enjoy your warmer weather!

Dave, it turns out we are not the only ones mystified. But yes hot water apparently does freeze faster than cold water under many conditions. Even the scientists are mystified but recognise the effect, and have named it the Mpemba effect after a Tanzanian "discovered" it in 1969. But it has been known apparently as far back as Aristotle and no doubt beyond. But the scientists are still grappling with the "why" this happens.

A rundown on the science is here Link

Explanations include Evaporation, dissolved gasses, convection, effect on the surrounding air, and supercooling. It is quite complex and totally counterintuitive.

So it turns out those old blown-away Swedes and Norwegians and Russians who settled the northern plains and mountains of the USA knew exactly what they were talking about. It just took science 100years to catch up.

Sure - certainly in England no engine will freeze in an insulated workshop just old men making a fuss?

Explanations include Evaporation, dissolved gasses, convection, effect on the surrounding air, and supercooling. It is quite complex and totally counterintuitive.

Re this phenomenon - I put part of it down to viscosity - and possibly thixotropy in water (London bonding and all that).

The way it has been demonstrated by some is to throw a container of each hot and cold water on frozen ground - where the hot freezes first. I argue, in this particular case, that viscosity is a major factor as the hot water would spread much further than the cold.

May I remind all previous posters about freezing temperatures that water actually expands a few degrees above freezing point. So when water is actually frozen it has already expanded and busted the weakest point like say a pipe. There is, therefore, a need to keep the temperature about 5° F above the freezing temperature.