Note: Descriptions are shown in the official language in which they were submitted.
CA 02465601 2004-02-10
WO 2004/042332 PCT/CA2003/001684
SOLID STATE ILLUMINATOR FOR BI-COLOURED PORTED WATER LEVEL GAUGES
Field of the Invention
The present invention relates, generally, tv a device for accurate
determination
of water lave! in a high pressure boiler drum or other similarwaterlsteam
apparatus. More
specifically, the present invention utilizes an array of vertically arranged,
bi-coloured, solid
state light emitting diodes (LEDs) to provide light that is focussed through
an array of
precision lens and projected though either steam or water and displayed upon a
view
screen. The presence of either steam orwater at a level corresponding to each
LED inthe
array of LEDs wii! result in a clear and unmistakable colour change observable
on the view
screen.
Background of the invention
The design and use of bi-coloured light for determining water levels in
steam boilers is well taught and documented in the aft. Traditionally,
incandescent light
is passed through coloured lenses as the light source. These designs suffer
from
numerous deficiencies in their fragility, efficiency, power requirements and
life span. An
incandescent light source utilises a fragile filament operating at high
temperature. This
filament can easily become damaged and break when subjected to continued
vibration.
In addition, the high operating temperature of the filament limits the life
span of the
incandescent light. The same incandescent light source requires a high level
of power
to operate and only a small percentage of this power is converted to usable
light. The
remaining power is-lost, predominantly as heat.
Numerous liquid level indicators can be found in the art to which the present
invention provides advances. United States Patent No. 2,610,729 describes an
indicating gauge in which a vertlca! column containing both water and steam
includes a
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multitude of bores which pass horizontally through the column and allow for
visual
inspection of the contents of the column present at the corresponding level.
An
operator is able to inspect and determine the level at which the contents of
the column
shift from water to steam.
1n United States Patents Nos. 2,024,815 and 2,115,889, indicators that
utilize the reflective and refractive properties of water, steam and light are
revealed. In
each case, the operator inspects the individual gauges within a plurality of
gauges and
is able to determine the water/steam level by observing a colour change
associated
with the level corresponding to the change from water to steam. The device of
U.S.
Patent No. 2,115,889 provides an additional means to visually inspect the
gauge at a
greater distance, more specifically, at a position located far below the
gauge. The light .
is provided in each of these devices via an incandescent light source.
United States Patent No. 4,836,022 describes a bi-colour fluviograph for
use in steam boilers and provides improvement to the intensity of light
provided from
the light source and includes benefits aimed at reducing the frequency of
maintenance
of the fluviograph. The light is provided by a flourescent lamp and the
colours are
introduced via two planes, one painted red, and the other green. The
ftuviograph
increases the intensity of the red light to allow for its operation in murky
or turbulent
water conditions that would render most previous devices inoperable. A further
advantage is that the device need not be cleaned as frequently. Traditionally,
the
impurities in the water contained within the boiler would deposit on the lens
and
gradually reduce the effective light transmitted. This effect is lessened by
increasing
the light intensity.
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Summa~yr of the Invention
The present invention provides a gauge system that incorporates a solid state
illuminator and corresponding view screen, which can help accurately determine
the water
level in steam boilers or similar devices, and do so in a safe, economical,
and efficient
manner.
The use of light emitting diodes as a light source in a level gauge
illuminator provides
reduced operating costs in that much or virtually all power is converted to
visible light. In
addition, the nominal life of an LED is typically 100,000 hours. An LED is
generally unaffected
by continued vibration. An LED is capable of producing red and green light
directly,
eliminating the need for coloured glass. Finally, an LED requires minimal
power to operate
and the use of a solid state illuminator would be intrinsically safe in a
hazardous environment.
According to an aspect of the present invention, there is provided a bi-colour
water
level gauge for use in determining the water level in a steam/water
environment, for instance
in a boiler steam drum, heater, or other piping or pressure vessel, the gauge
comprising an
electronic printed circuit board containing an array of high-intensity, narrow
beam first colour
and second colour light emitting diodes, eg. red/green light emitting diodes;
the electronic
printed circuit board being mounted on an electronics divider board; a lens
divider board
comprising a plurality of ports, each of the ports being individually aligned
with the light
emitting diodes; a heat divider for separating the electronic printed circuit
board from exposure
to high temperatures existing at an external housing, the heat divider
typically comprising rows
of offset slots to reduce heat transmission; and display means, such as a view
screen, onto
which light originating from the light emitting diodes is projected for
inspection by an operator.
According to another aspect of the present invention, there is provided a bi-
colour
water level gauge illuminator for use in determining the water level in a
steam/water
environment, for instance in a boiler steam drum, heater, or other piping or
pressure vessel,
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the illuminator comprising an electronic printed circuit board containing an
array of high-
intensity, narrow beam first colour and second colour light emitting diodes,
eg. red/green light
emitting diodes; the electronic printed circuit board being mounted on an
electronics divider
board; a lens divider board comprising a plurality of ports, the ports being
individually aligned
with the light emitting diodes; and a heat divider for separating the
electronic printed circuit
board from exposure to high temperatures existing at an external housing, the
heat divider
typically comprising rows of offset slots to reduce heat transmission.
According to a further aspect of the present invention, there is provided a bi-
colour
water level gauge for use in determining the water level in a steam/water
environment, for
instance in a boiler steam drum, heater, or other piping or pressure vessel,
the gauge
comprising an electronic printed circuit board containing an array of high-
intensity, narrow
beam first colour and second colour light emitting diodes, eg. red/green light
emitting diodes,
the electronic printed circuit board being mounted on an electronics divider
board; a lens
divider board comprising a plurality of ports, each of the ports containing
means, such as a
piano-convex lens, for focusing light originating from the light emitting
diodes, the ports being
individually aligned with the light emitting diodes, and preferably
substantially equal in number
thereto; a heat divider for separating the electronic printed circuit board
from exposure to high
temperatures existing at an external housing, the heat divider typically
comprising rows of
offset slots to reduce heat transmission; and display means, such as a view
screen, onto
which light originating from the light emitting diodes is projected for
inspection by an operator.
According to yet another aspect of the present invention, there is provided a
bi-colour
water level gauge illuminator for use in determining the water level in a
steam/water
environment, for instance in a boiler steam drum, heater, or other piping or
pressure vessel,
the illuminator comprising an electronic printed circuit board containing an
array of high-
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intensity, narrow beam first colour and second colour light emitting diodes,
eg. red/green
light emitting diodes; the electronic printed circuit board being mounted on
an electronics
divider board; a lens divider board comprising a plurality of ports, each of
the ports
containing means, such as a piano-convex lens, for focusing light originating
from the light
emitting diodes, the ports being individually aligned with the light emitting
diodes, and
preferably substantially equal in number thereto; and a heat divider for
separating the
electronic printed circuit board from exposure to high temperatures existing
at an external
housing, the heat divider typically comprising rows of offset slots to reduce
heat
transmission.
A further aspect of the invention provides a method for determining the water
level
in a boiler steam drum, heater, or other piping or pressure vessel comprising
the steps of
projecting a first light from one or more light emitting diodes of a first
colour; projecting a
second light from one or more light emitting diodes of a second colour;
passing said first
and second lights through a column containing steam and water at a varying
level to an
opposing side of said column relative to said light emitting diodes, typically
onto a
projection screen positioned on the aforementioned opposing side; observing
the position
of the first and second light at varying vertical levels along the column, eg.
as observed on
the projection screen; and determining the presence of water or steam at each
of said
varying levels based upon the observed positions of the first and second
lights.
Another aspect of the present invention provides a bi-colour water level gauge
illuminator for use in determining the water level in a boiler steam drum,
heater, or other
piping or pressure vessel, the illuminator comprising a housing having a gauge
mounting
side adapted for mounting the illuminator to a first tense side of a bi-colour
water level
gauge, the housing comprising at least one aperture defined in the gauge
mounting side of
the housing; a plurality of first colour and second colour light emitting
diodes arranged and
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configured within the housing to facilitate the emission of bi-colour
illumination through the
aperture, and through ports or windows of the gauge to a second tense side of
the gauge;
and a heat divider for separating the light emitting diodes from exposure to
high
temperatures existing at the gauge.
As yet another aspect, the invention provides a method of illuminating a
column of
a fluid level gauge used in determining the water level in a boiler steam
drum, heater or
other piping or pressure vessel, the method comprising the steps of projecting
a first light
from one or more light emitting diodes of a first colour; projecting a second
light from one
or more light emitting diodes of a second colour; and passing the first and
second lights
through the column to an opposing side of the column relative to the light
emitting diodes,
wherein the presence of water or steam at varying vertical levels in the
column may be
determined by observing the position of the first and second lights along the
column.
Brief Description of the Drawings
Figure 1 a is a perspective view of a conventional water level gauge,
demonstrating
a vertical array of viewing ports;
Figure 1 b is a perspective view of an individual port;
Figure 1c is a exploded, perspective view of an individual port;
Figures 2a, 2b, and 2c constitute a perspective view of a system according to
an
embodiment of the present invention including the component parts from left to
right
namely a level display, a level gauge, and an illuminator;
Figure 3a is an exploded, perspective view of an illuminator according to an
embodiment of the present invention;
Figure 3b is a completed, perspective view of the illuminator of Figure 3a;
Figure 3c is an exploded, perspective view of an electronics divider board,
and a
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lens divider board according to an embodiment of the present invention;
Figure 3d is a perspective view of the lens divider board of Figure 3c,
including an
array of lenses, one lens of which is presented in an exploded view;
Figure 3e is an exploded perspective view of an external housing of the
illuminator
according to an embodiment of the present invention;
Figure 4a is a perspective view of an inner display end plate according to an
embodiment of the present invention;
Figure 4b is an exploded, perspective view of a level display according to an
embodiment of the present invention;
Figure 4c is a completed, perspective view of the level display of Figure 4b;
Figure 5 is an exploded, perspective view of a level display according to a
second
embodiment of the present invention; and
Figure 6 is a completed, perspective view of the level display of Figure 5.
Detailed Description of the Invention
The system of the present invention comprises two main components an
illuminator, and a level display.
These two main components interact with a conventional water level gauge 22 as
can be seen in Figure 1 a, with one port thereof illustrated in more detail in
Figures 1 b and
1 c. As illustrated, the conventional water level gauge 22 is made up of a
series of ports 3,
arranged vertically along a column 2, each comprising an opening 4 protected
by glass,
though which light may pass. When installed on a water boiler, or similar
device, water or
steam or a combination of the two will pass from the boiler, through the pipe
1, and into the
column 2. An operator, who wishes to inspect the column 2 may peer through the
series
of ports 3, and determine the level of water within the gauge, and
correspondingly, the
boiler.
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As can be seen in Figures 2a, 2b, and 2c, an illuminator 14 and level display
23
can be adapted to interact with the level gauge 22 by an interface that is
formed between
hooks 18 on the outer housings of the illuminator and the level display and a
bolt 17 on the
column 2 of the level gauge.
Referring to Figures 3a-3e, the illuminator may comprise an electronic printed
circuit board (PCB) 10 containing an array of red and green light emitting
diodes (LEDs) 19,
an array of piano-convex lenses 13, equal in number to the number of groups of
LEDs 19, and
an external housing 20, made up of a first portion 8 and a second portion 9,
adapted for
attachment to a conventional water level gauge. The PCB 10 utilizes precision
resistors to
regulate the current supplied to each LED 19. The PCB further utilizes a
terminal block
corresponding to each LED 19 that provides a connection point for the input
power and allows
for jumpering between individual PCBs 10. The PCB 10 is mounted on an
electronics divider
11 which is, in turn, attached to the first portion 8 and second portion 9 of
the external
housing. A fens divider board 12 is positioned adjacent to the array of LEDs
19, and is
attached to the first and second portions 8, 9 of the outer housing. This lens
divider board 12,
has a number of piano-convex lenses 13, equal to the number of groups of LEDs
19 present
on the PCB 10. These lenses 13 focus light through an equal number of holes 21
in a heat
divider 26 on the first portion 8 of the external housing so as to provide
light to be passed
through a level gauge.
The first and second portions 8, 9 of the illuminator may further comprise an
array of
offset slots 24 extending substantially completely from top to bottom. These
slots 24 are
designed and offset to limit the transmission of heat originating in the level
gauge. The typical
operating environment of a level gauge for a steam boiler is very high,
typically in the range
of 696 degrees F (369 degrees Celsius). By introducing these slots to the
design, heat
transmission by conduction from the level gauge to the PCB board assembly and
the LEDs
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CA 02465601 2005-11-29
is reduced, and the LEDs are isolated from these high operating temperatures.
Referring now to Figures 4a, 4b, and 4c, the level display 23 may comprise a
viewing
screen 15 for viewing the light transmitted from the LEDs, having passed
through a
conventional water level gauge, and optional adjustable end plate 5 for
blocking the unused
red and green images, a first portion 16 and second portion 7 of an external
housing adapted
for attachment to a conventional water level gauge, and a viewing screen
connection portion
30 for connection of the viewing screen and, optionally, the end plate to the
external housing.
The adjustable end plate 5 provides openings 6 at the levels of concern and
blocks the display
of unwanted red and green light. The adjustable end plate 5 ensures that the
operator can
clearly distinguish between the levels and reduces error.
Referring now to Figures 5, and 6, which illustrate a possible alternate
embodiment
of the level display 23, a second heat divider 25 is provided for reducing the
transmission of
heat from the level gauge 22 to the view screen 15. Additionally, an array of
offset slots 24
extends substantially completely from top to bottom of the level display 23.
These slots 24
are designed and offset to limit the transmission of excess heat originating
in the level gauge
22, which may impair the functionality of the display.
Industrial Applicabilityr
The bi-colour water level gauge and illuminator device taught herein generally
provides
an improved means for determining the water level in a boiler steam drum,
heater, or similar
water/steam device.
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