The New Student's Reference Work/Ice harvesting
ICE HARVESTING
From Brown Bros. |
ICE HARVESTING. The snow is first cleared by means of scrapers very much like the scrapers used in building roads or making excavations for the foundations of buildings. It takes two people to do this, one to lead the horse, the other to hold the scraper to its work.
From Brown Bros. |
After the snow has been cleared away deep parallel grooves are cut in the ice with what is called an “ice plow.” These ice plows are sometimes driven by steam but horses are usually used as you see in the picture. With this plow grooves are cut in the ice in both directions so that the ice is divided into blocks about three feet square. Unless the ice is very thick the plow cuts very nearly through.
From Brown Bros. |
After the ice has been cut nearly through with the plow the rest of the work is done with a saw, one end of which runs down into the water. After the ice cakes are sawed out by one set of men another set pry them apart with crowbars, while a third set floats them down channels, made for the purpose, toward the ice house.
From Brown Bros. |
This picture gives a rear view of the ice elevator which you see at the side of the ice house in the first picture. The cakes of ice are floated to the foot of this elevator and carried up into the ice house by an endless chain arrangement similar to the device that carries away the straw and chaff from a threshing machine. At intervals on this chain, which runs over sprocket wheels at the other end, are cleats. The distance between these cleats is a little over the width of a cake of ice. The men at the foot of the elevator push a cake into each section as it comes along. The ice is carried by the elevator up into the warehouse, where it is packed in sawdust.
From Brown Bros. |
This picture shows the various tools used by ice harvesters and the men who deliver ice at your door. Here you see various forms of ice tongs, ice shavers, files and stones for sharpening the tools, ice axes and ice scales. Besides these there are augers for drawing off surface waters, forked bars for prying the cakes loose, trimming bars for squaring them, and chisels, adzes and edging tongs used in packing the ice in the warehouse.
ARTIFICIAL ICE
From Brown Bros. |
HOW ARTIFICIAL ICE IS MADE. In making artificial ice the first step is to get pure water. The water is boiled and then allowed to stand so that the impurities may settle. After this sediment has settled the water is drawn off and distilled; that is, it is turned into steam and this steam is condensed back into water, as your breath condenses on the window on a cold day. This picture shows a condenser. In the condenser is a series of parallel pipes inside of which cold water is kept running. The steam to be condensed comes in through one of the large pipes which enter the condenser at the top. The other large pipe supplies the cold water and connects with the coil of smaller pipes inside. As the steam is condensed into water it falls to the bottom of the condenser and passes out through the pipe at the end of the condenser nearest you.
From Brown Bros. |
Distilled water is run through several kinds of filters. In this illustration the two large cylinders you see in the rear are charcoal filters. After the water has passed through these cylinders it is pumped through pipes into the kind of filters at which you see these men at work. The men are putting on a fresh filter cloth. Over this cloth is fastened another and coarser filter of perforated metal. Under the cloth is another disk of perforated metal. The water enters by the small pipe in the rear, is forced through the perforated metal and cloth and comes out into the larger pipe you see in front.
From Brown Bros. |
After the water leaves the condenser it is still warm, so it is made to pass through another series of parallel pipes. Over these pipes a spray of cold water is kept playing, which still further cools this distilled water on its way to the filters shown in the next illustration. In making artificial ice the greatest care is taken to secure pure water. Before it is even distilled in the condensing system this water is boiled and then allowed to stand so that the impurities may settle. It is then drawn off from this settling tank, converted into steam and condensed.
From Brown Bros. |
This man is filling the cans with distilled water. It is in these cans the ice is made. On the bottom of the tube you see held in its place in the can with braces is a valve, opening upward. When this valve is pressed against the bottom of the can it lets out enough water to fill the can almost to the top. When the water reaches a certain height it is stopped by a floating check valve. A floating check valve is one which has a hollow metal ball attached so that when the water in which it floats reaches a certain height it turns the valve and either shuts off the water or releases it, as desired.
From Brown Bros. |
Most artificial ice is made by what is called the compressor system. It is called the compressor system because the ammonia with which che freezing is done is first compressed by means of powerful steam pumps. These pumps then force it through pipes over which cold water is running. This cold water bath still further condenses the gas to a liquid state, which drives out all the heat there is in it. The illustration shows how water is kept playing on the pipes containing the compressed ammonia.
From Brown Bros. |
After the ammonia has been condensed to a liquid state. It passes into a great cylinder called an evaporator. Here it begins to expand again back to a gas and passes into parallel pipes like those you have just seen. But these pipes run through a tank filled with brine. When the ammonia is condensed to a liquid form it gives up all its heat, just as water does when it turns to ice. Then, when it is allowed to expand in passing through the pipes in the brine tank, it absorbs the heat from the brine and makes it freezing cold In this brine tank are set the cans of distilled water to be frozen. This illustration shows the cans being lowered into the brine.
From Brown Bros. |