Improvements in Blowing and Exhausting Fans.
Year: 1897

page_text: Improvements in Blowing and Exhausting Fans.
I, RICHARD JAMES HODGES, of 61, Forburg Road, Stoke Newington, London, N.,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has for its object an improved construction of centrifugal fan,
whereby the friction resulting from the revolving impeller in contact with the
compressed air within the casing is avoided, additional space being obtained by
making the casing wider than the fan, thus allowing the air to escape more
readily from the influence of the rotating impeller, which effects a large saving
of the power hitherto wasted in air friction; enabling a much greater volume
of air to he passed, besides rendering the fan noisless in working.
In constructing a simple centrifugal fan according to my invention, I form the
rotating impeller by fixing suitable blades on either side of an annular or solid
disc which is mounted on a shaft or spindle running in suitable bearings. To
the inner sides of the casing are fixed short inlet pipes which support and hold
in place conoidal cheek plates forming the side shroudings, between which the
fan revolves.
In steel plate fans for large volume such as are used for forced draught, ventila-
tion, exhausting &c. I employ flat instead of conoidal cheek or shroud plates on
either side of the impeller.
In operation, the air leaving the periphery of the fan is free to disperse into
the space at either side between the check plates and the casing, and is immediately
out of the direct rotary motion of the air following it from the revolving fan.
Dated this 25th day of November 1897.
Improvements in Blowing and Exhausting Fans.
I, RICHARD JAMES HODGES. of Cazenove Works, Dunstable, Bedfordshire,
Engineer, late of 61, Forburg Road, Stoke Newington, London, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:.
-
This invention has for its object an improved construction of centrifugal fan,
whereby the friction resulting from the revolving impeller in contact with the
compressed air within the casing is avoided, additional space being obtained by
making the casing wider than the fan, thus allowing the air to escape more

page_text: readily from the influence of the rotating impeller, which effects a large saving
of the power hitherto wasted in air friction: enabling a much greater volume
of air to be passed, besides rendering the fan noisless in working.
Referring to the accompanying drawings, Fig. 1 is a cross section of an exhaust
or ventilating fan constructed as described in my Provisional Specification, with
steel plate or sheet iron casing A, and is of the single inlet type, B the inlet tube
is bolted to the side casing and projects inward holding in place the cheek or
shroud plate C. The annular disc 1) is supported and driven from the shaft E
by the spider F, on both sides of the disc are blades of suitable curve G.
cheek or shroud plates C may be formed as a double flanged ring casting as shewn,
the smaller flange being bolted to the side casing and the larger flange forming
the shroud or cheek enclosing the sides of the revolving fan.
The
Fig. 2 is a cross section of an ordinary blowing fan constructed of cast iron,
the inlet tubes B and conoidal shroud or cheek plates C are shewn as being cast
with each half of the fan casing A, which casing may be made of any width
independant of the width or fan, but the said shroud or cheek plates may be made
separate and bolted or fixed to the casing sides as in Fig. 1.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. The construction of exhausting, ventilating &c. fans as described in Fig. 1,
having the casing wider than the revolving fan, and having inlet tubes projecting
inwards and supporting flat or conoidal cheek plates or shrouds to enclose the
sides of the revolving fan.
2. In conjunction with check plates or shrouds, the annular disc D having
lades G attached to both sides thereof.
3. The construction of fans for blowing exhausting ventilating &c. having their
casings wider than the revolving impellers, the entering air &c. being guided to
the centre of such impeller by means of short tubes between the casing and
revolving fan, the ends of such tubes supporting conoidal or flat cheek or shroud
plates, to enclose the sides of, and protect the revolving fan from the pressure
and friction of air delivered into the said casing.
4. The construction of centrifugal fans having the several parts arranged as
in Claims 1, 2 & 3, for the purpose, object and improvement mentioned in my
Complete Specification as above.
Dated this 24th day of August 1898.
RICHARD JAMES HODGES.