Ветряные мельницы, страница 5

be expected,  and also indicates the size of  single-action pump suitable for a given lif t when the gpar ratio is 1 to

3.

GaDoiiB per Approximate

Total Lif t Hour.  Bore of  Pumpu Stroke.

26 feet 100 2 in.  3i in.

50 „ 50 2 „ 1}

100 „ 26 IJ „ IJ

The power required for the above-mentioned duties is only a f raction of  what the engine should be capable of

developing in a good breeze ; but an ample allowance has to be made for f rictional and other losses.  If  too large a

pump be f itted,  the mill will not start in light winds.

A 2-in.  bore "lif t and force" " windnuir' pump could be purchased for about 30s. ,  and in the end this will

probably be found the cheapest and most satisfactory plan to adopt.  The pump is driven by a pin screwed into

the side of  the spur-wheel and secured by a lock nut.  Three or four holes should be drilled and tapped at

dif ferent distances f rom the centre of  the wheel,  in order that the length of  stroke may be adjusted (Fig.  66,  d

and e).  If  the wheel have spokes,  and these are too slight to admit of  drilling,  a clamp with a projecting pin

could,  no doubt,  be devised,  or a disc crank could be made out of  a pipe f lange.

If  the pump be driven direct,  without the intervention of  gearing,  an eccentric on the wind-wheel

220 THINGS WORTH MAKING.

shaf t would make the best job ; but a direct drive is not reoommended,  as the pump would run so fast that it

would have to be reduced to almost microscopic dimensions.

In any case the pump stroke will be so short,  and the side swing so slight,  that a jointed connecting rod is hardly

required ; for all but the shortest strokes,  however,  it will be necessary to curve the upper part of  the rod so that

it shall clear the wind-wheel shaf t.

Pump Bod,  —^A continuous wooden rod—say,  1 in.  square,  but thicker at the top end,  so as to admit a brass

bush to work on the crank pin—will,  therefore,  answer the double purpose of  connecting and pump rods.  The

connection at the bottom end can be made by bolting it to the " bow ** which is supplied with the pump; any

intermediate joints that may be required can be made with 1-in.  by J-in.  f ish-plates,  about 6 in.  long.

If  the pump be not more than 12 f t.  below the crank pin,  one guide will suf f ice.  As the pump rod must revolve

with the head,  it will require to be thickened up to a circular section where it passes through the guide.  The

latter (shown at z in Fig.  65,  a) should be made in halves and screwed or bolted to a bar nmning across the

tower.  The best lubricant for wooden- rubbing surfaces is plumbago and sof t soap.

In conclusion it may be pointed out that if  the

A SMALL WIND MOTOR.  JBJBl

mill be required for driving machinery,  bevel gearing will be required to transmit the power f rom the head.  A 5-foot mill is,  of  course,  very small for any practical purpose,  such as driving a lathe ; it would,  however,  drive a

small dynamo of ,  say,  30 watts output,  which would be quite suf f icient for charging small accumulators.

A SMALL WIND MOTOB. ,

The foundation of  the wind-wheel required for this is the f ront wheel of  an old bicycle with f ront spindle and

cones complete.  To the rim of  this are attached eight or a dozen vanes of  stout sheet tin or zinc 8 in.  long and 4

to 6 in.  wide,  lying at an angle of  30^ to the plane of  the rim.  The vanes will be more ef f icient if  curved to the arc

of  a circle of  about the same radius as the wheel,  the concave side facing the wind.  Solder or rivet to the back of

each vane a rib of  strip iron ) in.  thick,  projecting ^ in.  beyond the tip and 1| in.  at the other,  where it is twisted