Note: Descriptions are shown in the official language in which they were submitted.
~L~2S~
-- 2 --
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to a critical wind direction
indicator.
More particularly, the invention relates to an indicator
of the type which shows the direction of the wind at extremely
low wind velocity as well as at high velocity. It is part-
queerly useful in areas likely to be invaded by toxic gas, for
example, HIS, as a warning to people to vacate these areas.
This is a common problem in the oil fields of Western Canada.
SUMMARY OF THE INVENTION
An aim of the invention is to provide an indicator
which operates at low wind velocities of as little as one mile
per hour and, at the same time, is effective at high wind veto-
cities of, say, 100 miles per hour.
Broadly speaking, a device according to the invention
includes a frame and diaphragm means on the frame, providing a
wind passage, which enlarges and contracts with the velocity of
the wind. Vane means is connected to the frame and extends to
leeward so as to receive the wind from the passage.
More specifically, the frame is made up of a circular
windward hoop and a smaller leeward ring concentrically arranged
with the hoop and appropriate connecting framework. A support
extends from Gone side to the other of the hoop and mounts a vane
which projects to the leeward of the frame. A diaphragm arrange-
mint is draped over the frame to extend from the windward hoop
to the leeward ring. This diaphragm may take the form of a
flexible fabric slipcover which is normally cylindrical, but
.
~2S28~
-- 3 --
provided at its leeward side with an elastic margin so that it
is normally drawn in as a pleated skirt against the frame to a
substantially frusto-conical shape. The cover is capable of being
blown outward towards its cylindrical form so that it provides a
wind passage of variable cross-sectional area. The vane is pro-
fireball made up of a metal frame to which is fastened a fabric
cover.
Alternatively, the diaphragm can be made of a number of
tapered strips, for example, of plastic, which are mounted side-
by-side with their windward ends tethered to the windward hoop
and their leeward ends held together by an elastic ring. The
action of this type of device is similar to that of the slip-
cover type.
In operation, at low wind ve10cities, the diaphragm is
held in against the frame and prevents a minimum wind passage.
As the velocity of the wind increases the leeward side of the
diaphragm is forced outwards to provide a larger and larger
passage for the wind. At low velocity, the wind is concern-
treated, by the passage, against the vane, so that the latter
acts to show the wind direction even at low velocity. When the
wind increases the diaphragm opens up to allow the wind to pass
through without undue pressure on the structure or on
the pole on which it is mounted.
Desirably, the frame is mounted on the end of a pole,
desirably on ball bearings, so that it is readily rotatable in
response to light wind pressure.
~5;~1~9
-- 4 --
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the nature of the
invention, it will now be referred to in more detail, by
reference to the accompanying drawings, which illustrate pro-
furred embodiments, and in which:
FIG. 1 is a general perspective view of a critical
wind direction indicator and mounting pole,
according to the invention, mounted between
a potential source of noxious gas and a
work zone;
FIG. 2 is a greatly enlarged perspective view of
the direction indicator proper and its
connection to the pole;
FIG. 3 is a side elevation of the structure shown
in Fig. 2 on a further enlarged scale;
FIG. 4 is a further enlarged fragmentary elevation,
partly in section, showing the mounting of
the direction indicator proper on the pole,
FIG. 5 is a general perspective view, on more or
less the scale of Fig. 2, illustrating
another form of wind-resistance element
or diaphragm;
FIG. 6 is a vertical fragmentary cross-section,
partly in elevation, substantially on the
scale of Fig. 3 of the form of device of
Fig. 5.
FIGS. 7 and 8 illustrate a preferred structure
for connecting the frame and vane.
3L2
-- 5 --
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Fig. 1 of the drawings, the wind direction
indicator B is shown mounted on a substantially vertical pole A
firmly fixed to a base on the ground through a bearing 14,
allowing the indicator B to rotate in a substantially horizontal
plane. C diagrammatically illustrates a source of noxious gas.
A worker D is shown vacating a work zone, which the indicator
tells him is downwind from the gas, and E is another operator
standing off to the side in a zone which the indicator shows is
safe. As will be explained in detail, the indicator B includes
a structure providing a passage through which the wind passes,
a vane F, leeward of the passage, to keep the passage facing the
windward direction, and means which increases or decreases the
wind resistance of the device in response to wind velocity.
With particular reference to Fig. 2, indicator B is
made up of a support frame 13 having a narrow frusto-conical
hoop 15 disposed in a substantially vertical plane. The hoop
15 carries a framework made up of an internal ring 17, concern-
trig with the hoop 15, but of smaller diameter, and spaced
from it. The ring 17 is connected to the hoop 15 by a series
of struts 19 extending diagonally inward and forward from the
edge of the hoop 15 to join the ring 17.
A connecting rod 23 is joined to the bottom of the
ring 15 and is journal led in the bearing 14. A stabilizing
support member 25 extends forwardly and downwardly between the
bottom of the ring 17 and a mid-part of the rod 23. A supporting
strut 27 extends from each side of the rod 23 diagonally upwards
to engage the hoop 15.
~25Z~3~
-- 6 --
The bearing 14 is mounted on the post A, as best shown
in Fig. 4. The bearing 14 is made up of a sleeve 31 engaging
the top of the post A, for example, by a threaded connection, as
shown. The connecting rod 23 has a lower end 29 of reduced
section which enters the sleeve 31 where it is engaged by ball
bearings 33 mounted inside the sleeve 31. Other types of mount-
ins could be used to allow the connecting rod 23 to rotate
relative to the post A.
Extending from the top to the bottom of the hoop 15 is
a mounting rod 35 on which there is mounted the inner end of a
vane F having an extensive surface disposed in a vertical plane,
as best shown in Fig. 2. Struts 41 and 42 extend outwardly from
the ring 17 to engage the top and bottom of the vane F, so as to
support it relative to the frame.
The vane F is made up of a wire Frame 37 on which there
is mounted a fabric panel 39 to provide a wind-influenced sun-
face acting to maintain the vane F pointing in the direction the
wind is blowing.
Indicating streamers 52 are connected to the top and
bottom front edges of the vane F.
Extending about the hoop 15 is one margin of a narrow
tubular slipcover or wind-resistance member G, defining a
diaphragm, made up of flexible fabric, whose other margin 63
contained an elastic 65 which gathers that side of the cover in-
wards in pleats against the ring 17 and struts 19, as best Shannon Fig. 3. The support frame 13 and cover G provide a wind
passage leading to the vane F. Preferably the cover G protrudes
just beyond the ring 17.
A
3L2ZS~8~
-- 7 --
Operation
In operation the wind Boyce through the passage formed
inside the hoop 15 and cover G, the margin 63 defining a leeward
outlet to the wind passage. The wind blowing against the vane F
causes the latter to rotate into alignment with the wind
direction.
In operation, in a light wind, the cover G will remain
with its margin 63 in a gathered in position, more or less as
shown in full lines in Figs. 3 and 5 and will concentrate the
wind passing within the wind passage defined by the diaphragm
on the vane F.
As the wind becomes stronger, it forces the inner end
of the leeward side of the wind resistance member G outwards so
that it offers less resistance to wind going through the passage.
This reduces the pressure that would otherwise be exerted on the
indicating device B, its connecting rod 23, bearing 14, and
pole A.
Figs. 5 and 6 illustrate an alternate form of wind
resistance element Go, mounted on a frame similar to that
illustrated in the previous Figures. In Figs. 5 and 6, the
reference numerals identifying the similar parts are the same
as those in Figs. 1 to 4 and the letters the same with a sub-
script 1.
the element Go is made up of a number of side-by-side
plastic strips 151 each of which has a windward end connected
to a hoop 15 and a leeward end connected to a common elastic
band 65.
Jo
~25~
-- 8 --
The strips 151 are slightly tapered from the windward
end to the leeward end so that when they are in the position
shown in Fig. 5 and in full lines in Fig. 6, their edges touch
and the assembly of plastic strips forms a substantially frost-
conical tube.
When the wind becomes strong enough against element Go,
the leeward ends of the strips are moved outwards with the
elastic 65 stretching until there is a gap between respective
strips which widens as it reaches the leeward end of the element
10 Go.
Reaction of the element Go is thus similar to that of
the member G. At low wind pressures the element Go remains in
the position shown in Fig. 5 with the end of the element Go
resting against the frame and presenting a throat to tunnel the
wind centrally and increase its velocity as it acts on the vane
F1. As the wind rises beyond a predetermined point the wind
pressure starts to force the strips outward both enlarging the
throat at the windward end of the element Go allowing more
wind to pass and also allowing the wind to escape between the
respective strips.
The strips 151 have been shown held to the hoop 15 by
fasteners. Alternatively, the strips could be held by rings
extending around the hoop 15 and through the margins of the
strips. The fabric cover of member G could be similarly
connected.
Z~9
g
Variable Factors
To give an idea of a practical device, normally the
hoop 15 would have a diameter of about 24 inches and the ring 17
about 16 inches with about 6 inches there between. The frame can
be made of aluminum, although steel or brass could be used. The
size and nature of the mounting pole A can vary. The device
could be mounted on top of a building or a vehicle. The pole A
could be of steel pipe from to 11 inches depending on the
circumstances. The pole A should be sufficiently strong so that
the indicator B is kept level to give an accurate reading. The
fact that the indicator B offers less resistance at high wind
velocity lessens the strain on the pole A.
The material of the diaphragm or member G is prefer-
ably fluorescent woven fabric, desirably nylon. The material
must be flexible and elastic to allow it to billow out and
straighten out the pleats when subjected to high wind pressure.
The ribbons 52 on the leeward end of the vane F give a
rough visual estimate of the velocity of the wind.
The wind direction indicator B is preferably spaced
from the ground an average of 15 to 20 feet but can be anywhere
from 10 to 100 feet or even higher, say, 150 feet, if on the
top of a drilling rig. HIS is heaver than air and will make
its way towards the ground so it may be desirable to have the
indicator B 20 to 25 feet above the ground. It could be
mounted on a 400 barrel production tank.
The alternative form of diaphragm or element Go can
be made of any suitable material with a flexible plastic
material preferred.
I
- 10 -
Desirably the vane F and the diaphragms G and Go are
fluorescent so as to be clearly visible.
The fabric panel 39 of vane F can be fluorescent
orange or red sail cloth which can be held in place by strips
of Velcro (trade mark), snaps or buttons.
Fig. 7 is a side elevation, partly in section, showing
a preferred arrangement for detachably securing the vane F to the
frame. A pair of spaced-apart parallel channel members or troughs
70 and 71 extend between the leeward ring 17 and mounting rod 35
extending from the top to the bottom of the windward ring 15.
The vane F has a supporting frame including the struts
41 and 42 extending diagonally from wire frame 37 to join
parallel bars 80 and 81 which, in turn, meet a perpendicular
rod 83 extending between them. A fabric cover (not shown in
Figs. 7 and 8) fills the space within the frame 37. Thus the
vane F constitutes a self-contained unit which is detachably
connected to the frame 37.
This is done by sliding the parallel bars 80 and 81
into the channel members 70 and 71 and tightening set screws 86
to hold them in place.
Making the vane F as a separate unit and providing for
the wind passage frame to be detachable from the mounting rod
35 makes the entire unit portable and readily mountable or
dismountable.
I'
