Improvements in Ventilating Fans or Air Propellers.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Ventilating Fans or Air Propellers.
I ARTHUR SCOTT of 11 St. Pauls Street Brinnington Stockport in the County of
Lancashire Engineer do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement.-
My present invention relates to ventilating fans or air propellers used more
especially for removing volumes of vapour, air, or floating dust at a low pressure so
as not to create a very perceptable draught, such for instance as fans used for
ventilating or removing floating dust from buildings or warehouses, the said fans
being driven by belt or other gearing, and the object of my present invention is
to form the blades of said fans or ventilators so that a higher degree of efficiency
is attained, that is to say a greater volume of air is removed with a less force than
is the case with ventilating fans having blades constructed in the ordinary manner;
in order to attain this I form one third, or thereabouts of the length of each blade in
the form of an elliptical curve, or to more particularly describe the same, the portion
of each blade beginning at the outer periphery thereof and extending towards the
boss of fan to about one third the length of said blade is made in the form of an
elliptical curve, by which means it is found that an increased suction takes place, and
the flying off of the an or dust at the outer periphery of the blades is entirely
prevented.
I also form the cross section of each blade in the form of an elliptical curve
throughout, or to more particularly describe the same I form the entire cross section
of each blade concavo-convex, by which means the blades obtain a firmer grip
upon the air and floating dust or vapour, thus forcing the same forward in greater
volume.
By means of constructing the blades of said air propellers or ventilating fans in
the combined form described a higher degree of efficiency is acquired, or in other
words a less amount of power is needed to force or propel a larger amount of
air than can be obtained when using fans or air propellers having blades constructed
in the ordinary way.
In order that my present invention may be well understood and readily carried
into effect I attach a sheet of drawings to illustrate the same, of which the following
1s a description Fig. 1 is a side elevation, Fig. 2 is a cross section taken on line a, a,
of fig. 4 Fig 3 a cross section taken on line b, b, of fig 4, and fig. 4 a plan of my
improved blade for a ventilating fan or air propeller.
Like letters denote corresponding parts in each view.
The blade c has three parts
or thereabouts of its length in the form of an elliptical curve c', the whole of its cross
section is also of an elliptical curve c², see figs. 2 and 3.
By means of constructing the blade of air propellers or ventilators in the manner
illustrated a larger amount of air can be propelled with less power than is the case
with air propellers having blades constructed in the ordinary manner.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim 1s.
1 In ventilating fans or air propellers used for the purpose specified the use of
blades constructed in the combined form substantially as hereinbefore described and
illustrated at figs. 1, 2, 3, and 4, of the accompanying drawings.
Dated the 7th day of May 1880
H. F. BOUGHTON, M.I.M.E.,
Barnsley, Agent.