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J. Perelman
"Entertaining physics". Book 1.
Chapter 6. Thermal phenomena


We have already described earlier hours without works (or rather, without special plant), a device that is based on changes in the pressure of the atmosphere. Let us now describe the same winding watch, based on the thermal expansion.

The mechanism depicted in Fig. 1.

Fig. 1. A watch that is wound by themselves.

The main part of it - terminals Z1 and Z2, are made of a special metal alloy with a large coefficient of expansion. Rod Z1 rests on the teeth of the wheel X so that when the elongation of the rod from heat gear turns a little. The rod Z2 gears the teeth of the wheel Y when shortening from cold and rotates it in the same direction. Both wheels mounted on the shaft W1, rotation of which turns a large wheel with scoops. Scoops capture mercury particular object sticking its bloated in the lower trough, and transferred to the top; hence the mercury flows to the left wheel, with scoops; filling the latter, the mercury causes the wheel to rotate; this comes in motion a chain QC, covering wheels K1 (common shaft W2 with a large wheel) and K2, the last wheel spins the winding spring hours.

What is done with mercury, which resulted from scoops left wheel? It flows down the inclined chute R1 again to the right wheel, so that here again to start your move.

The mechanism, as we can see, must move forward, not stopping until such time as will be lengthened or shortened terminals Z1 and Z2. Therefore, for winding it is only necessary that the temperature of the air is alternately increased and then decreased. But it is happening by itself, without worries with our side: any change in ambient temperature causes a lengthening or shortening of the rods, resulting in slowly, but constantly twisted spring hours.

Can we call this watch the “eternal” engine? Of course, no. The watch will go on indefinitely until you wear out the mechanism, but the source of their energy serves to heat the ambient air; thermal expansion of these accumulated hours in small portions, so as continuously to spend it on the movement of the watch hands. This type of engine, as it requires care and maintenance costs of their work. But it does not create energy from nothing: the primary source of its energy is the warmth of the Sun, warming the Earth.

Another specimen-winding watches similar device is shown in Fig. 2 and 3. Here the main part is glycerin, expanding with increasing temperature and stirring while some weight; drop shipping and driven by the clock mechanism. Because glycerin solidifies only at 30° C and boils at 290° C, this mechanism is suitable for hours on city squares and other open spaces. Fluctuations in temperature of 2° is sufficient to ensure the progress of these watches. One instance they were tested during the year and has shown satisfactory progress, although throughout the year to the mechanism never touched a draw hand.

Fig. 2. Diagram of the device-winding watches other pattern.

Fig. 3. Winding watch, in the basement of hours hidden tube with glycerol.

Whether the benefit is on the same principle to cater for the larger engines? At first glance it seems that this type of engine should be very cheap. The calculation gives, however, a different result. To plant ordinary hours for the day you need energy only about 1/7 of kilogrammetres. This is a second round score of 600,000 stake of kilogrammetres; and since horsepower is equal to 75 KGM per second, the capacity of one of the clock mechanism is only 45000000 stake horsepower. So, if the cost of expanding rods of the first clock or the second device will appreciate at least one penny, capital consumption per horsepower of such engine will be 1 kopeck * 45 000 000 = 450 000 rubles.

Almost half a million rubles for 1 horsepower is probably expensive for the type of engine...

Entertaining physics J. Perelman


System Orphus


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