AN IMPROVEMENT IN VENTILATING APPARATUS
Year: 1884

page_text: I, GEORGE GREIG of Harvieston in the county of Kincardine, North Britain,
Engineer do hereby declare the nature of my invention for "AN IMPROVEMENT IN
VENTILATING APPARATUS" to be as follows:-
When it is required to produce a current of air in a large channel, as for the
ventilation of mines, tunnels or other extended spaces, there is an objection to the
use of a ventilating wheel or fan of large diameter, because the speed of the parts
of its blades near the axis is very much less than that of the parts near the
periphery, and consequently back currents are apt to be established at the central
part of the wheel. Again, when the large channel is subdivided into a number of
smaller channels, there is a loss of power in establishing and maintaining currents
along these, resulting from the friction against the partitions that separate the
channels.
Now according to my invention, when it is desired to send a current of air along
a channel of large sectional area, I arrange side by side a number of comparatively
small ventilating wheels or fans disposing them so as to occupy as much as possible
of the whole area of the channel. These being all worked together produce
a number of parallel currents of equal' speed making up together a main current
which occupies the whole of the channel and having no partitions in its course is
subject only to the frictional resistance of the walls of the channel.
In the intervals between and at the sides of the ventilating wheels or fans there
may be apertures for passage of currents that are induced by the lateral action of
the currents produced by the wheels or fans, and accompany them in their course
along the channel.
11
100
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,

page_text: I, GEORGE GREIG, of Harvieston in the county of Kincardine, North Britain,
Engineer do hereby declare the nature of my invention for "AN IMPROVEMENT IN
VENTILATING APPARATUS" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :—
When it is required to produce a current of air in a large channel, as for the
ventilation of mines, tunnels or other extended spaces, there is an objection to the
use of a ventilating wheel or fan of large diameter because the speed of the parts
of its blades near the axis is very much less than that of the parts near the
periphery, and consequently back currents are apt to be established at the central
part of the wheel. Again, when the large channel is subdivided into a number of
smaller channels, there is a loss of power in establishing and maintaining currents
along these, resulting from the friction against the partitions that separato the
channels.
Now according to my invention, when it is desired to send a current of air along
a channel of large sectional area, I arrange side by side a number of comparatively
small ventilating wheels or fans disposing them so as to occupy as much as possible
of the whole area of the channel. These being all worked together produce
a number of parallel currents of equal speed making up together a main current
which occupies the whole of the channel and having no partitions in its course is
subject only to the frictional resistance of the walls of the channel.
In the intervals between and at the sides of the ventilating wheels or fans there
may be apertures for passage of currents that are induced by the lateral action of
the currents produced by the wheels or fans, and accompany-them-in-their-course-
along the channel.
The accompanying diagram shews how fan ventilating wheels W may be
arranged to cause flow of air along a large channel of square section, by creating
a number of parallel currents, these wheels being all mounted in one plane so as to
draw or propel air through the circular apertures in a partition or screen crossing
the channel. Besides these apertures, other apertures A indicated by their dotted
outlines may be made through the partition so that additional currents parallel to
those created by the wheels, may be caused by the inductive action of the latter,
the effect being to produce a general flow of approximately uniform velocity
throughout the sectional area of the channel.
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 :-
For producing air currents in large channels, the arrangement therein of
a number of ventilating wheels working uniformly together so as to produce
parallel currents substantially as described.