Tri Comp
Year: 1887

page_text: Date of Application, 12th Oct., 1887
Complete Specification Left, 12th July, 1888
Complete Specification Accepted, 17th Aug., 18
I, RICHARD JAMES HODGES of 112 Osbaldeston Road Stoke Newington London N.
Engineer do hereby declare the nature of this invention to be as follows:-
:-
This Invention has for its object the construction of Duplex and Triplex Compound
Blast Fans, capable of producing a continuous flow of air or Gas or Vapour &c. at a
greater pressure than hitherto, at the same time decreasing the speed or revolutions of
the impeller, and which fans are specially adapted for supplying high pressure Air &c.
to cupolas, blast and other furnaces, smiths hearths, portable forges &c., but may also
be used for exhausting and ventilating purposes.
In order to obtain a much higher pressure by centrifugal force than hitherto I
construct the Fans upon a Duplex and Triplex Compound principle thereby compressing
the Air &c. two, or three times according to the pressure required.
When constructing a fan upon what I term the Duplex Compound principle I
employ two fans or impellers, the first of which I call the "low pressure fan" and
the second the "high pressure fan" which act upon the Air &c. in the following manner
viz.
The Air &c. entering the first or low pressure fan or impeller is compressed by centri-
fugal force and leaves the periphery of the impeller at a certain pressure; the air thus
compressed is conducted to the inlet of the second or "high pressure fan" by which
it is further compressed to the extent of from forty to eighty per cent.
The Triplex Compound Fan differs from the Duplex Fan already described by
having three or more fans or impellers which I call respectively "low"" inter-
mediate" and "high pressure" by which the Air &c. is compressed three or more
times, and consequently brought to a higher pressure than when only two fans or
impellers are used.
In constructing a Duplex or Triplex Compound Fan according to this my Inven-
tion I fix upon a horizontal shaft or spindle two or more fans or impellers arranged
at certain distances apart, which revolve within a cylindrical or suitable casing having

page_text: a central inlet at one end thereof; through the centre of such inlet the shaft or spindle
passes and is held in position by a suitable bearing or bearings; the outlet is placed
at the side of the casing furthest from the inlet.
Between the fans or impellers are placed suitable division plates which are bolted or
fixed to the casing and which division plates have central openings through them of
about equal diameter to the inlet in the casing.
Projecting longitudinally from one side of these division plates are a series of vanes
or blades which curve spirally outward from the edge of the central openings to the
casing, and which very nearly fill up the space between the fans or impellers and the
division plates.
The use of these projecting vanes is as follows viz. :-The air &c. escaping from the
periphery of the first fan having acquired a rapid rotary motion, on coming into
contact with the spiral vanes is gradually directed towards the central opening in the
first division plate, through which it passes at an increased pressure due to its initial
momentum being concentrated by means of the spiral vanes or blades, enters the
second fan or impeller and is again compressed by centrifugal force.
If more than two fans or impellers are employed the above operation is repeated,
thereby, further increasing the pressure of the air &c. until the outlet is reached at the
other end of the casing.
Dated this Eleventh day of October 1887.

page_text: I, RICHARD JAMES HODGES of 112 Osbaldeston Road, Stoke Newington London,
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 :-
This Invention has for its object the construction of Duplex and Triplex Compound
Blast Fans, capable of producing a continuous flow of Air, Gas, or Vapour &c. at a
greater pressure than hitherto, at the same time decreasing the speed or revolutions of
the impeller, and which Fans are specially adapted for supplying high pressure air &c.
to Cupolas, Blast, and other Furnaces, Smith's hearths, Portable Forges &c., but may
also be used for exhausting and ventilating purposes.
In order to obtain a much higher pressure by centrifugal force than hitherto I
construct the Fans upon a Duplex and Triplex Compound principle thereby
compressing the Air &c. two, three, or more times, according to the pressure
required.
When constructing a fan upon what I term the Duplex Compound principle I
employ two Fans or impellers, the first of which I call the "low pressure Fan" and
the second the "high pressure Fan" which act upon the Air &c. in the following
manner vizt. :-
The Air &c. entering the first, or low pressure Fan or impeller is compressed by
centrifugal force and leaves the periphery of the impeller at a certain pressure; the
Air thus compressed is conducted to the inlet of the second or
high pressure fan
"
"
by which is further compressed to the extent of from forty to eighty per cent.
The Triplex Compound Fan differs from the Duplex Fan already described by
having three or more fans or impellers which I call respectively "low"-" inter-
mediate "and "high pressure" by which the Air &c. is compressed three or more
times, and consequently brought to a higher pressure than when only two fans or
impellers are used.
In constructing a Duplex or Triplex Compound Fan according to this my Invention
I fix upon a horizontal shaft or spindle two or more fans or impellers arranged at
certain distances apart, which revolve within a cylindrical or suitable casing having
a central inlet at one end thereof; through the centre of such inlet the shaft or spindle
passes and is held in position by a suitable bearing or bearings; the outlet is placed
at the side of the casing furthest from the inlet.
Between the Fans or impellers are placed suitable division plates which are bolted
or fixed to the casing and which division plates have central openings through them
of about equal diameter to the inlet in the casing.
Projecting longitudinally from one side of these division plates are a series of vanes
or blades which curve spirally outward from the edge of the central openings to the
casing, and which very nearly fill up the space between the Fans or impellers and the
division plates.

page_text: The use of these projecting vanes is as follows vizt. :-The air &c. escaping from the
poriphery of the first Fan having acquired a rapid rotary motion, on coming into
contact with the spiral vanes is gradually directed towards the central openings in the
first division plate, through which it passes at an increased pressure due to its initial
momentum being concentrated by means of the spiral vanes or blades, enters the
second Fan or impeller and is again compressed by centrifugal force.
If more than two fans or impellers are employed the above operation is repeated,
thereby further increasing the pressure of the Air &c. until the outlet is reached at the
other end of the casing.
-
In order that this Invention may be more readily understood I annex hereto one
sheet of Drawings which forms part of this specification and illustrates my Invention
clearly.
Referring to the Drawings
Figure 1. illustrates a Duplex Compound Fan, in section longitudinally with the
driving shaft.
Figure 2. is a Triplex Compound Fan, in section longitudinally with the driving
shaft.
Figure 3. is a Duplex Compound Fan having two inlets. and two low pressure
impellers.
Figure 4. is a side elevation of Fig. 3. having the outer cover and bearing removed,
and shows the division plate and spiral or curved blades fixed thereto.
Similar letters of reference are shown in corresponding parts wherever they occur.
a. a. Figure 1 is a hollow casing into which the Air &c. is compressed and forced
through the outlet (b). Passing through the centre of said casing is the driving
shaft (c) one end of which is supported by the annular cover (d). Fixed upon this
shaft are two impellers (e¹) and (e) which are shown as discs having blades projecting
from one side thereof, such blades vary in width and area according to the intensity
of blast required. Placed between the impellers is a division plate (f) through which
is a central opening; projecting longitudinally from one side of this division plate
are spiral or curved blades (g) which extend from the edge of the central opening
outward to the casing (a) and nearly fill up the space between the division plate and
impeller (e). When the Machine is in operation the Air &c. passes through the
inlet in the cover (d) and enters the impeller (e) and leaving its periphery in a state
of rapid rotary motion, strikes against the curved blades upon the division plate and
is deflected towards the opening in the centre thereof through which it passes and
enters the second or high pressure impeller (2) by which it is forced into the
casing (a. a.).
Figure 2. shows the arrangement for a Triplex Compound Fan, and differs from the
Duplex shown in Fig. 1. by having three or more impellers (e¹, e, e³) and division
plates (f, f) by which the Air &c. is further compressed.
Figure 3, shows a Duplex Compound Fan having two inlets which is suitable for
compressing large volumes of Air &c., and consists of a central casing (a), (a) with
outlet (b). Passing through the centre of this casing is the driving shaft (c) supported
by bearings fixed to the annular covers (d d); fixed upon this shaft are three
impellers (e, e e³); between the two impellers (e¹) and (e³) are two division
plates (f) with curved blades (9) (9) fixed thereto and arranged so as to allow the
high pressure impeller (e) to revolve between them
Figure 4, is a side elevation of Fig. 3 with the annular cover (d) removed, and
shows the division plate (f) and curved blades (9).
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 is :
1. The construction of Duplex and Triplex Compound Fans for the purposes of
Blast, Exhaust, or Ventilation, having two or more impellers fixed to and rotating
together with a shaft, in conjunction with the division plates and curved blades as
herein before described and illustrated in Figures 1 and 2.

page_text: 2. The division plates having spiral or curved blades fixed thereto, and placed
between the impellers of Blast, Exhaust, or Ventilating Fans, for the purpose of
conducting the Air &c. from the periphery of the low pressure impellers towards the
central openings in the division plates, thereby increasing the pressure &c. of the
blast.
3. The construction of Compound Fans having two or more impellers fixed to a
sleeve, and revolving upon a fixed shaft for the purposes above described.
4. The combination of impellers of different capacities or dimensions mounted side
by side upon one shaft or sleeve, and having division plates with curved blades for
the purpose of increasing the pressure of blast in ordinary centrifugal Fans.
Dated this 11th day of July 1888.