The French Agricultural Machínery Company has recently made a very
interesting application of the screw for raising water for submersion
and irrigation, and, to our knowledge, it is the first of its kind.
It is only necessary to examine the accompanying cut and observe the
dimensions of the machine (which was constructed according to plans of
Mr. Grulet) to recognize the fact that we have here a really practical
application.
The screw, which constitutes the principal peculiarity of the system,
has six blades, with a pitch of 0.465 m. On making 210 revolutions
per minute it is capable of raising about 435 liters (95 gallons) per
second to a height of 1.2 m (about 4 feet). The shaft that drives it
revolves in a bearing which is bolted to a cross piece that is affixed
to the cylindrical chamber. This latter consists of a cast iron case
that is easily taken apart, and of a strong cylinder of iron plate
whose upper extremity is connected, by means of riveted angle iron,
with the bottom of the sluice. In the interior of the cylinder there
are two cones, whose bases embrace the hub of the screw in such a way
as to obtain a continuous superposition of the layers of liquid, and
prevent bodies in suspension from penetrating between the rubbing
surfaces of the bearing. One of the cones is made of iron plate, and
is connected with the principal cylinder by four radiating braces and
small angle irons, and the other is cast in a single piece with the box
of the pivot.
The rotary axis is guided above by two pillow blocks held by the cross
pieces of a frame that is riveted to the sides of the sluice. Finally,
this latter terminates in a hinged gate which regulates the flow of the
water.
Two beams that rest upon the sides of a stream will suffice in most
cases to support the entire affair.
The mechanical duty of the apparatus is estimated at about 65 per cent.
In the apparatus put up by Mr. Grulet, the motive power is furnished
by a portable 10 H.P. engine. The boiler is a return flame one, with
movable fire place, and the steam cylinder has a diameter of 0.2 m. (8
inches) for a piston stroke of 0.3 m. (about 12 inches). Before the
apparatus was finally put in place it was sent to the last exhibition
at Carcassonne, where it attracted very much attention from visitors.
Its great regularity in working was particularly remarked. This
quality, and the simplicity of its construction and the ease with which
it may be put in place, are valuable features in apparatus that are
designed to be looked after by inexperienced persons, and to operate in
open air far from repair shops.--_Revue Industrielle_.
[Illustration: GRULET'S SCREW FOR RAISING WATER.]