The Sewerage of Sea Coast Towns

ention to the pumping station is so much in excess of the cost of power and the sum required for the repayment of the loan for th

the highest point desired the pump may be started, and when it is lowered to a predetermined low water level the pump will stop; but it is impracticable to control the engine in the same way, so that although the floats are a useful accessory to the plant during the temporary absence of the man in charge they will not obviate his more or less constant attendance. An electric motor may be controlled by a float, but in many cases trouble is experienced with the switch gear, probably caused by its exposure to the damp air. In all cases an alarm float should be fixed, which wo

ation: P

G PLATE"

ce pa

economically practicable, as even if the water is available in the vicinity of the pumping-station, considerable work has generally to be executed at the point of supply, not only to store the water in sufficient bulk at such a level that it can be usefully employed, but also to lead it to the power-house, and the

of a wheel composed of a number of short sails fixed to a steel framework upon a braced steel tower, have been used for many years for driving machinery on farms, and less frequently for pumping water for domestic use. In a very few cases it has been utilised for pumping sewage, but there is no reason why, under proper co

E No

LY VELOCI

Number of days in year

rly velocity of t

| 10 m.p.h. | 15 m

----+------+-

86 16 88

12 15 12

86 39 13

56 36 12

51 34 14

02 34 13

16 33 15

67 46 15

30 26 13

·94 37 1

----+------+-

·4 131·7 2

rs included in the foregoing table, which had the least and the most

E No

ANALYSIS

the mean velocity of the wind was respec

wind (No. 8) | Year of

20 | 5 1

h. m.p.h. | m.p.h. m

----+----+---

1 23 27

9 23 28

0 20 23

16 23 28

24 30 3

2 22 26

8 29 31

23 30 1

3 25 30 1

7 21 26

1 20 26

19 24 2

----+----+---

5 272 329 1

. It must be remembered, however, that this does not by any means imply that during such days the wind did not rise above six miles per hour, and the probability is that a mill which could be actuated by a six-mile wind would have been at work during part of the time.

nimum. From the following figures (Table No. 13) it will be seen that, generally speaking, when there is very little wind there is very little rain Taking the ten years enumerated in Table

E No

SS THAN

+------+----+-

No. | Days on | |

s in | which no | R

ar. | rain fell.

+------+----+-

4 | 2 | .6

13 | 2 |

| .025, .01, .

| / .02, .08, .1

| \

| .10, .43, .01,

| .10, .11, .0

1 | 2 | .4

| .07, .035, .02

.145, .20, .33,

7 | / .03, .23,

\ .045

+------+----+-

| 48 | Average r

he 48 day

there are practical considerations which limit the height. In America many towers are as much as 100 ft high, but ordinary workmen do not voluntarily climb t

to assume that on an average a fifteen miles per hour wind was available for eight hours per day, and from this he

14 DUTY OF

er of

he United States Department of Agriculture at Cheyenne, Wyo.,

E No

x WINDMILL IN

Wind (mile

15 16-20 21-

overcome by providing large storage capacity, but this cannot be done for sewage without creating an intolerable nuisance. In the latter case the storage should not be less than twelve hours dry weather flow, nor more than twenty-four. With a well-designed mill, as has already been indicated, the wind will, for the greater part of the year, be sufficient to lift the whole of the sewage and storm-water, but, if it is allowed to do so, the standby engine will deteriorate for want of use to such an extent that when urgently needed it will not be effective. It is, therefore, desirable that the attendant should run the engin

a windmill is a very small matter, and the saving which may be obtained by the reduction of the amount of attendance necessary. Generally speaking, a mill 20 ft in diameter is the largest which should be use

l2 ft mills being the most efficient sizes. When the diameter exceeds l2 ft, the efficiency rapidly falls off, because the peripheral velocity remains constant for any particular velocity or pressure of the wind, and as every foot increase in the diameter of the wheel make

sh manufacturers turning out well-designed and strongly-built machines in large numbers. Fig. 19 represents the general appearance and Fig. 20 the details of the type of mill made by the well-known firm of Duke and Ockenden, of Ferry Wharf, Littlehampton, Sussex. This firm has erected over 400 windmills, which, after the test of time, have proved thoroughly efficient. From Fig. 20 it will be seen that the power applied

l9.-General View o

etails of Windmill Manufa

, Little

k disc, which has been an objectionable feature in some other types. The position of the crank shaft relative to the rocker pin holes is studied to give a s

s used, which permits of a simple method of changing the length of stroke by merely altering

ents an ellipse to the wind instead of a circular face, thus decreasing the area exposed to the wind gradually until the wheel reaches its final position, or is hauled out of gear, when the edges only are opposed to the full force of the wind. The whole weight of the mill is taken upon a ball-