U.S. patent number 3,895,901 [Application Number 05/497,413] was granted by the patent office on 1975-07-22 for fluidic flame detector.
This patent grant is currently assigned to The United States of America as represented by the Secretary of the Army. Invention is credited to Elmer L. Swartz.
United States Patent |
3,895,901 |
Swartz |
July 22, 1975 |
Fluidic flame detector
Abstract
A fluidic flame monitoring device is disclosed, the device
comprising a fdic amplifier, either of the bistable or proportional
type, the power stream of which is modulated or switched in
accordance with the temperature above an external flame. Connected
to a control port of the fluidic amplifier is a chamber coupled to
a source of fluidic pressure, the chamber incorporating a vented
pressure regulating output. In the preferred inventive embodiment,
an elongated thin-walled tube is coupled between the pressure
regulating output of the chamber and the atmosphere, the flow
resistance of the tube varying in response to the temperature of an
external flame applied thereto. In one preferred embodiment, the
absence of a flame alters the control signal pressure at the
control port of the fluidic amplifier, switching the output power
stream thereof. The switching of the output power stream is
detected as an indication of flameout. When a proportional
amplifier is utilized, modulation of the output power stream occurs
in response to variations in flame temperature. The device can be
utilized to control and shut off the fuel supply to an external
burner in response to flameout.
Inventors: |
Swartz; Elmer L. (Annandale,
VA) |
Assignee: |
The United States of America as
represented by the Secretary of the Army (Washington,
DC)
|
Family
ID: |
23976760 |
Appl.
No.: |
05/497,413 |
Filed: |
August 14, 1974 |
Current U.S.
Class: |
431/77;
137/804 |
Current CPC
Class: |
F23D
14/725 (20130101); F23N 5/027 (20130101); F15C
1/008 (20130101); Y10T 137/2065 (20150401) |
Current International
Class: |
F23D
14/72 (20060101); F23N 5/02 (20060101); F15C
1/00 (20060101); F23N 005/02 () |
Field of
Search: |
;431/77 ;137/804,805
;73/363 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Favors; Edward G.
Attorney, Agent or Firm: Edelberg; Nathan Gibson; Robert P.
Elbaum; Saul
Government Interests
RIGHTS OF THE GOVERNMENT
The invention described herein may be manufactured, used, and
licensed by or for the United States Government for governmental
purposes without the payment to me of any royalty thereon.
Claims
What I claim is:
1. A fluidic flame monitoring device comprising: a fluidic
amplifier means having an inlet channel, an outlet channel, and a
control port communicating with an interaction region such that a
control signal applied to said control port modulates a power
stream flowing between said inlet and output channels; readout
means coupled to said outlet channel for providing an indication of
the pressure therein; a chamber coupled to a fluid source and
having an output connected to said control port to provide said
control signal thereto, said chamber further incorporating a vented
pressure regulating output; and means coupled to said pressure
regulating output for controlling the amount of venting
therethrough in response to the temperature of an external flame;
whereby the pressure within said chamber is varied by said external
flame and the power stream within said fluidic amplifier is thereby
modulated and indicated.
2. A device as defined in claim 1, wherein said means for
controlling the venting of said pressure regulating output of said
chamber comprises an elongated tube coupled between said pressure
regulating output and the atmosphere, the flow resistence of said
tube varying in response to the temperature of an external flame
applied thereto.
3. A device as defined in claim 2, wherein said source of fluidic
pressure for said chamber delivers a constant flow fluidic
signal.
4. A device as defined in claim 2, wherein said fluidic amplifier
is a bistable amplifier, said readout means thereby indicating the
presence or absence of a flame.
5. A device as defined in claim 2, wherein said fluidic amplifier
is a proportional amplifier, said readout means thereby indicating
the temperature of the flame.
6. A device as defined in claim 2, further including in combination
therewith a fuel supply line for an external flame burner, a
pressure actuated flow control valve in said supply line, and
wherein said outlet channel of said fluidic amplifier is connected
to said flow control valve to provide the pressure for actuation
thereof, whereby said fuel supply is shut off in the absence of a
flame.
Description
BACKGROUND OF THE INVENTION
This invention generally relates to flame monitoring devices and is
particularly concerned with a flame monitoring device manufactured
of fluidic components.
For purposes of safety, as well as for other control purposes, it
is often times necessary to monitor the presence or absence of a
flame in a given piece of equipment. For example, and as concerns a
heating system utilizing oil burners, it is necessary to detect the
absence of a flame so that the fuel supply to the burner can be
rapidly shut off. Another environment in which flame detectors have
found utility is monitoring the occurrence of a flameout in
aircraft engines, so that suitable corrective measures can be
taken. Flame monitoring devices also find utility in fire alarm
systems and the like.
Considering the wide-spread utility as just briefly indicated
above, the prior art is replete with various apparatus all suitable
for detecting the presence or absence of a flame. Most of such
apparatus, however, exhibits one or more disadvantages,
disqualifying the apparatus for use in a particular environment.
For example, many flame monitoring devices are electrical in
nature, precluding their safe utilization in an explosive
atmosphere. One specific such electrical device, utilizing
thermocouples exhibits an extremely slow response time. Optical
monitoring devices, on the other hand, necessarily incorporate a
viewing area and it is often times difficult to maintain the
viewing area clean and thus ensure reliability of the device.
Mechanical apparatus, on the other hand, typically incorporate many
moving parts, decreasing the useful life of the apparatus and
further degrading the response time thereof.
SUMMARY OF THE INVENTION
It is thus apparent that a need exists in the flame monitoring art
for the provision of a device of markedly different construction
and which serves to overcome the above-noted disadvantages of the
prior-art. It is the primary objective of the instant invention to
provide such a novel flame monitoring device.
A further objective of the instant invention is the provision of a
flame monitoring device which utilizes fluidic components and
requires virtually no moving parts.
Still another objective of the instant invention is the provision
of a flame monitoring device which exhibits a rapid response time
and which can be utilized in explosive environments with a high
degree of safety.
Yet, another objective of the instant invention is the provision of
a flame monitoring device which not only has the capability of
indicating the presence or absence of a flame, but which further
can indicate the temperature of the flame so monitored.
These objectives are implemented by the instant invention which
will be seen to comprise a fluidic flame monitoring device
utilizing a fluidic amplifier, either of the bistable or
proportional type, having an inlet channel, an outlet channel, and
a control port communicating with an interaction region such that a
control signal applied to the control port modulates a power stream
flowing between the inlet and outlet channels. Connected to the
control port and providing the control signal thereto is the outlet
of a chamber or tank which is coupled to a constant type flow or
volume fluid source. The chamber further incorporates a vented
pressure regulating output and an elongated thin-walled tube
constituting a means for controlling the amount of venting through
the pressure regulating output is connected thereto. When the
elongated tube is placed in an external flame, the viscosity of the
fluid flowing therein would suddenly increase as would the
effective tube flow resistence, thereby reducing the venting to the
atmosphere and causing the pressure within the tank or chamber to
increase. This increased pressure which, as aforestated,
constitutes the control signal, causes the power stream in the
outlet channel of the fluidic amplifier to be modulated. A readout
mechanism, such as a meter, detects the modulation or pressure in
the outlet channel and thereby serves to provide an indication of
the presence, or absence, of a flame. In the event that a
proportional amplifier is utilized, the amount of modulation,
rather than bistable switching, indicates the temperature of the
external flame.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention itself will be better understood and further features
and advantages thereof will become apparent from the following
detailed description of a preferred inventive embodiment, which
description makes reference to the appended sheet of drawing,
wherein the single FIGURE thereon represents in schematic
illustration one embodiment of the instant invention utilizing a
bistable fluidic amplifier for control of the fuel supply to an
external burner.
DETAILED DESCRIPTION OF THE PREFERRED INVENTIVE EMBODIMENT
With reference now to the drawing, the basic fluidic flame
monitoring device of the instant invention comprises a fluidic
amplifier means generally designated by reference numeral 10
having, in typical fashion, an inlet channel 12, at least one
outlet channel, such as channels 14 and 16, at least one control
port, such as control port 18 and 20 communicating with an
interaction region 22 such that a control signal applied to the
control port would serve to modulate a power stream indicated by
reference numeral 24 flowing between the inlet and outlet
channels.
In the illustrated embodiment, a bistable fluidic amplifier is
shown such that a change in control signal pressure at control port
20 will serve to switch the power stream from outlet channel 14 to
outlet channel 16, and vice versa. As will be appreciated from the
discussion herein-below, proportional amplifiers could similarly be
utilized to advantage, the basic requirement being that any such
fluidic amplifier should have a relatively high gain, and have the
capability of being back loaded without deleterious switching
effects.
With the embodiment of the invention shown, the fluidic amplifier
is "normally" biased such that the power stream flows in outlet
channel 16 in the presence of a "normal" pressure signal at control
port 20, the power stream switching to outlet channel 14 upon an
increase in the control pressure signal. As is also typical, the
fluidic amplifier of the invention includes several atmospheric
vents, such as vents 26 and 28 ensuring stable operation.
A chamber or tank 30 is provided having an outlet 32 connected to
the control port 20 to provide the control signal thereto. A fluid
source, such as source 34, is coupled to the chamber or tank 30,
source 34 preferably being of the variety providing a constant rate
of flow, or constant volume. Chamber or tank 30 further
incorporates a vented pressure regulating output indicated at
reference numeral 36. Coupled to this output is a means generally
designated by reference numeral 38 which controls the amount of
venting therethrough in response to the temperature of an external
flame indicated by reference numeral 40 as emanating from an
external oil burner or the like 42. In the preferred inventive
embodiment, means 38 constitute a thin-walled sensor tube which
communicates flow of fluid from the tank or chamber 30 to the
outside atmosphere. With the apparatus as shown, and as will be
evident, a portion of the fluid provided by source 34 is vented to
the atmosphere through the sensor tube, and a further portion is
provided as the control signal at control port 20. Suitable and
obvious pressure adjustments must, of course, be made such that the
input flow from the high impedance 34 will not create enough
pressure under normal conditions within the tank or chamber 30 to
cause the power stream 24 to switch from its normal condition
wherein it exits outlet channel 16, to its switched condition
exiting outlet channel 14 as is shown.
When a flame, such as flame 40, is placed under the sensor tub 38,
the viscosity of the fluid flowing therethrough would suddenly
increase, and the effective tube flow resistence would likewise
suddenly increase, thereby reducing the flow of fluid to the
atmosphere, i.e. reducing the venting, and causing the pressure
within the chamber or tank 30 to rise. A slight increase in this
pressure would cause the high gain fluidic amplifier 10 to switch
such that the power stream exits outlet channel 14 as shown. A
readout gauge 44, such as a pressure monitoring device, is coupled
to the outlet channel 14 of the fluidic amplifier and, under the
circumstances discussed above, readout gauge 44 will measure
pressure only when a flame is present.
If the flame should suddenly go out, the pressure of fluid within
the tank or chamber 30 would quickly return to its normal level and
the fluidic amplifier 10 would switch back to its bias or normal
side, wherein the power stream exits outlet channel 16. The
reaction time of the system is fast in that the fluid supply
through the tube 38 quickly cools the tube, and further due to the
fact that the tube 38 is contemplated to be constructed having
walls as thin as is feasible. In operation, response time of the
device as illustrated constitutes a fraction of a second.
One particular utility of the preferred embodiment of the invention
is to control the fuel supply to an external burner such as oil
burner 42. In this respect, the outlet channel 14 of the fluidic
amplifier 10 would be connected to a pressure actuated flow control
valve 46 in a fuel supply line 48 for the external burner 42. In
this fashion, the valve 46 would be normally biased in an open
condition and, when flame-out of the burner was detected, the
sudden drop of pressure at outlet channel 14 would cause the valve
46 to quickly shut off, and thus prevent oil from unsafely
accumulating at burner 42.
The basic device of the instant invention can be disposed at a
location remote from the high temperature area of flame 40. In this
respect, a conduit need only be coupled between the sensor tube 38
and the outlet 36 of the pressure chamber 30 as will be
evident.
For those applications in which temperature monitoring in addition
to flameout monitoring is desired, fluidic amplifier 10 would
constitute a proportional amplifier as opposed to the bistable
device above-discussed. In this event, a change in the temperature
of flame 40 impinging upon sensor tube 38 would effect a
proportional change in the amount of power stream flow through
outlet channel 14 in conventional fashion.
From the foregoing description, it should be evident that the
objectives set forth at the outset have been successfully achieved.
It is to be understood that the invention described above
constitutes but a preferred embodiment, and that obvious
modifications thereto can be made by a person skilled in the art.
ACCORDINGLY
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