PERCENTAGE OF THE TOTAL AMOUNT OF WATER TAKEN FROM THE RESERVOIR.
| Height of fall in feet. | Elevation of discharge above delivery valve of ram in feet. | ||||
|---|---|---|---|---|---|
| 15 | 18 | 21 | 24 | 27 | |
| Percentage. | |||||
| 2 | ·0724 | ·0583 | ·0402 | ·0307 | ·0255 |
| 3 | ·1327 | ·1020 | ·0807 | ·0651 | ·0532 |
| 4 | ·1960 | ·1535 | ·1234 | ·1020 | ·0854 |
| 5 | ·2614 | ·2068 | ·1686 | ·1404 | ·1189 |
| 6 | ·3282 | ·2614 | ·2146 | ·1800 | ·1535 |
| 7 | ·3960 | ·3170 | ·2614 | ·2203 | ·1885 |
| 8 | ·4647 | ·3733 | ·3090 | ·2614 | ·2248 |
| 9 | ·5341 | ·4303 | ·3572 | ·3030 | ·2614 |
| 10 | ·6040 | ·4877 | ·4058 | ·3450 | ·2984 |
| 11 | ·6745 | ·5459 | ·4549 | ·3874 | ·3357 |
| 12 | ·7453 | ·6040 | ·5043 | ·4302 | ·3733 |
| 13 | ·8166 | ·6627 | ·5540 | ·4732 | ·4112 |
| 14 | ·8881 | ·7217 | ·6040 | ·5166 | ·4494 |
| 15 | ·9600 | ·7809 | ·6543 | ·5601 | ·4877 |
| 16 | — | ·8404 | ·7048 | ·6040 | ·5263 |
| 17 | — | ·9001 | ·7555 | ·6480 | ·5650 |
| 18 | — | ·9600 | ·8064 | ·6921 | ·6040 |
| 19 | — | — | ·8574 | ·7364 | ·6430 |
| 20 | — | — | ·9086 | ·7800 | ·6823 |
| 21 | — | — | ·9600 | ·8254 | ·7217 |
| 22 | — | — | — | ·8701 | ·7612 |
| 23 | — | — | — | ·9150 | ·8007 |
| 24 | — | — | — | ·9600 | ·8404 |
| Height of fall in feet. | Elevation of discharge above delivery valve of ram in feet. | ||||
| 30 | 35 | 40 | 45 | 50 | |
| Percentage. | |||||
| 2 | ·0181 | ·0112 | ·0063 | ·0027 | — |
| 3 | ·0441 | ·0326 | ·0243 | ·0181 | ·0132 |
| 4 | ·0724 | ·0560 | ·0441 | ·0348 | ·0281 |
| 5 | ·1020 | ·0807 | ·0652 | ·0533 | ·0441 |
| 6 | ·1327 | ·1063 | ·0870 | ·0724 | ·0608 |
| 7 | ·1640 | ·1327 | ·1096 | ·0920 | ·0782 |
| 8 | ·1960 | ·1595 | ·1327 | ·1121 | ·0960 |
| 9 | ·2285 | ·1868 | ·1561 | ·1327 | ·1142 |
| 10 | ·2614 | ·2145 | ·1800 | ·1535 | ·1327 |
| 11 | ·2947 | ·2425 | ·2041 | ·1746 | ·1514 |
| 12 | ·3282 | ·2708 | ·2285 | ·1960 | ·1704 |
| 13 | ·3620 | ·2994 | ·2532 | ·2177 | ·1896 |
| 14 | ·3960 | ·3282 | ·2780 | ·2395 | ·2090 |
| 15 | ·4303 | ·3572 | ·3030 | ·2614 | ·2285 |
| 16 | ·4647 | ·3863 | ·3282 | ·2835 | ·2482 |
| 17 | ·4993 | ·4157 | ·3535 | ·3058 | ·2680 |
| 18 | ·5341 | ·4451 | ·3790 | ·3232 | ·2380 |
| 19 | ·5690 | ·4746 | ·4046 | ·3507 | ·3081 |
| 20 | ·6040 | ·5042 | ·4303 | ·3733 | ·3282 |
| 21 | ·6392 | ·5340 | ·4561 | ·3960 | ·3486 |
| 22 | ·6745 | ·5640 | ·4820 | ·4188 | ·3688 |
| 23 | ·7098 | ·5940 | ·5080 | ·4417 | ·3892 |
| 24 | ·7433 | ·6241 | ·5341 | ·4657 | ·4097 |
| Height of fall in feet. | Elevation of discharge above delivery valve of ram in feet. | ||||
| 60 | 70 | 80 | 90 | 100 | |
| Percentage. | |||||
| 2 | — | — | — | — | — |
| 3 | ·0063 | ·0017 | — | — | — |
| 4 | ·0180 | ·0112 | ·0063 | ·0027 | — |
| 5 | ·0307 | ·0217 | ·0150 | ·0099 | ·0063 |
| 6 | ·0441 | ·0325 | ·0243 | ·0180 | ·0132 |
| 7 | ·0580 | ·0441 | ·0340 | ·0264 | ·0205 |
| 8 | ·0724 | ·0560 | ·0441 | ·0351 | ·0281 |
| 9 | ·0870 | ·0682 | ·0545 | ·0441 | ·0360 |
| 10 | ·1020 | ·0807 | ·0651 | ·0533 | ·0441 |
| 11 | ·1172 | ·0934 | ·0760 | ·0627 | ·0524 |
| 12 | ·1327 | ·1063 | ·0870 | ·0723 | ·0608 |
| 13 | ·1483 | ·1194 | ·0983 | ·0821 | ·0694 |
| 14 | ·1640 | ·1327 | ·1096 | ·0920 | ·0782 |
| 15 | ·1800 | ·1460 | ·1211 | ·1020 | ·0870 |
| 16 | ·1960 | ·1595 | ·1327 | ·1121 | ·0960 |
| 17 | ·2123 | ·1731 | ·1444 | ·1223 | ·1050 |
| 18 | ·2286 | ·1868 | ·1561 | ·1327 | ·1142 |
| 19 | ·2449 | ·2006 | ·1680 | ·1430 | ·1262 |
| 20 | ·2614 | ·2145 | ·1800 | ·1535 | ·1327 |
| 21 | ·2780 | ·2286 | ·1920 | ·1640 | ·1420 |
| 22 | ·2947 | ·2425 | ·2041 | ·1746 | ·1514 |
| 23 | ·3114 | ·2567 | ·2163 | ·1853 | ·1609 |
| 24 | ·3282 | ·2708 | ·2185 | ·1960 | ·1704 |
For explanation of these tables [see page 177].
HYDRAULIC RAM.
A hydraulic ram or water-ram is a substitute for a pump for raising water by means of the energy of the moving water, of which a portion is to be raised. It was considered a notable discovery when it was demonstrated by Daniel Bernovilli, in the beginning of the 18th century, that water flowing through a pipe, and arriving at a part in which the pipe is suddenly contracted, would have its velocity at first very greatly increased.
The hydraulic ram owes its efficacy to the fact that when a flow of water in a pipe is suddenly stopped, a considerable force is generated by the momentum of the water, by its change from a state of motion to a state of rest. In practice, the pipe conveying water from the reservoir or head, connects with a chamber which has a valve opening downward, or outlet valve, allowing the current of water to pass on or escape when the valve is open; but on flowing the current in the pipe acquires sufficient force to close this valve, which checks the flow in the pipe.
The current is thus suddenly stopped; this causes a reaction, which produces pressure sufficient to open another valve (inlet valve) between the current-pipe and an air chamber, and a portion of water enters by means of the force of the current, but by so doing the current has spent its force; the outlet valve at the end of the chamber falls by its own weight, and the pressure in the pipe ceasing, the inlet valve in the air-chamber falls and closes the opening. The condition of things is then restored; the water then acquires a momentum which closes the outlet valve and forces more water again into the chamber. A very slight descending column is capable of raising one ascending very high. In all cases the drive-pipe or inlet pipe must be sufficiently long to prevent water being forced back into the reservoir. The air-chamber serves to keep up a steady supply from the reservoir, preventing spasmodic action. To prevent admixture of air with the water in the air chamber, which is caused by pressure of water when raised to a great height, a small hole should be made on the upper side of the inlet pipe, immediately in front of the same. By the action of the ram at each stroke, a partial vacuum is formed below the air chamber, and the air rushing through the small hole in the inlet pipe, passes into the air chamber, making good that which the water absorbs.
Note.—In 1797 Matthew Boulton (manufacturer and practical engineer, and in later life a partner of Jas. Watt, the Father of the steam engine) obtained a patent for a mode of raising water by impulse. The apparatus had excited much attention in France, under the name of Montgolfier’s hydraulic ram, and Boulton added to it a number of ingenious modifications, which were the basis of his patent.