Year: 1889

page_text: We, JAMES BENTLEY HOWORTH and FREDERICK CHARLES HOWORTH, both of
Bentley House, Great Lever, Bolton in the County of Lancaster. Ventilating
Engineers 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 :-
Our invention relates to ventilating fans or air propellors for ventilating rooms.
mines or ships and consists in an improved construction of the propellor and in an
improved method of mounting or applying the fans.
On the two sheets of drawings appended hereunto fig. 1 shows a front view, fig. 2
a side view, and fig. 3 a section of our improved propellor, fig. 4 showing the shape of
one of the blades before it is bent.
Fig. 5 Sheet II. shows our improved method of mounting or applying two of the
fans in front view, and fig. 6 in side view.
We cut the blades of the propellor out of sheet metal in the shape of a sector of
a circle with the back edge by preference slightly convex as shewn at a on fig. 4;
the leading edge b being either left straight as shewn in dotted lines or concave as
shewn in full lines. We cut a slot into the plate at c. The leading part of the
blade from the edge b to the dotted line d or thereabout, we leave plane or flat, and
the other part we bend so as to form part of the surface of a cone, having its apex
about or near the centre of the sector. To the flat part we rivet or otherwise attach
a stiffening bar e. We form the boss f out of two parts of f¹, f similarly to a flanged
shaft coupling and cut into one of them f³ grooves into which the stiffening bars of
the blades fit and secure the blades to the boss by gripping them between the flanges,
which we draw together by screws or bolts. By preference we pass a screw or bolt
through each of the stiffening bars as shewn by fig. 3, whereby they and the blades are
held in their places. By preference we bend the stiffening bars and blades as shewn
by fig. 3 so that they do not stand at right angles to the shaft but are inclined to
the same.
Four blades are shewn on the drawings as forming the propeller but less or more
may be used. The propeller is placed as usual into a ring or cylindrical case open

page_text: at both ends and the shaft carried in bushes. with arms extending to the case and fixed
thereto. The case is provided with two legs for fixing it in any position as may
be required.
Our further improvement consists in mounting two fans at the side of a divided
hood as shewn by figs. 5 and 6 sheet II. The hood 9 consists of two parts gl and g³
cast or bolted together having a square opening at the bottom and semicircular top.
The outer ends have circular openings in them and the fan casings h and h¹ are
attached to the same. The propellers i are both mounted upon the same shaft k
running in the bosses and carrying a driving pulley between the two parts of the
hood. The hood may be fixed upon a single ventilating flue or shaft, the two fans
replacing in this case a single fan of larger diameter or the flue may be divided as
shewn by fig. 5.. In. the. latter case the two fans may be arranged right and left
handed so as to exhaust air from both flues, which can be carried to different parts of
the building or pit, or both fans may be made the same, when one will exhaust
the air from or produce an up current in one flue and the other will propel the air
down the other flue and thus effect a circulation of air in a building, mine, or ship.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what
we claim is :
Firstly, in ventilating fans or air propellers the shape and curvature of the blades
substantially as herein described and illustrated by the drawings.
Secondly, the method of fixing the blades to the shaft by gripping them between
flanged bosses with grooves for the stiffening bars, substantially as herein described
and illustrated by the drawings.
Thirdly, the arrangement of two fans at the sides of a divided hood and mounted
on one shaft and driven by one pulley, substantially as herein described and illustrated
by the drawings.
Fourthly, arranging two fans, mounted upon one shaft and at the sides of a divided
hood connected to two flues, in such a manner that one of them causes an up current
and the other a down current in the flue connected to it, substantially as herein
described.