US2681590A - Apparatus for visual detection of suspended matter in fluid - Google Patents

Description

June 22, 1954 w. T. FLEMING 2,681,590

APPARATUS FOR VISUAL DETECTION OF SUSPENDED MATTER IN FLUID Filed Dec. 27, 1950 INVENTOR A WILL/AM I Fl HIM 6 ATTORNEY Patented June 22, 1954 APPARATUS FOR VISUAL DETECTION OF SUSPENDED MATTER IN FLUID William T. Fleming, West Orange, N. J., assignor to Specialties Development Corporation, Belleville, N. J., a corporation of New Jersey Application December 27, 1950, Serial No. 202,977

6 Claims. 1

. The present invention relates to apparatus for visually detecting suspended matter in fluid, and, more particularly, to improvements in smoke detectors primarily adapted for use on aircraft or other craft or vehicles where the space for such apparatus on the instrument panel is extremely limited.

Heretofore, visual smoke detectors have been utilized to supervise one or several compartments .or zones in which smoke may occur by continuously withdrawing samples of the air from such zones or compartments and passing a stream of air withdrawn through a beam of light to illuminate smoke particles suspended in the stream whereby the presence of smoke may be observed visually in the stream. In connection with such smoke detectors, it has been found that the illuminated particles can be seen more readily when looking in the direction toward the light source but obliquely thereto.

tector wherein stray light which might hinder the observer is reduced to a minimum.

Another object is to provide such a smoke detector wherein provision is made for readily determining whether or not the beam of light for illuminating the air stream is being directed through the stream.

A further object is to provide means for selectively rendering the light beam determining means just mentioned effective and ineffective.

Other and further objects of the inventionwill be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice. In accordance with the present invention, the

foregoing objects are generally accomplished by providing apparatus comprising in combination a casing having a sight opening including a window, a light source for providing a beam of light, means for directing the beam in the general direction of the opening but along one side of the window whereby the beam will be viewed obliquely through the window when looking therethrough, and means for conducting a stream of fluid into the light beam.

, In a preferred embodiment. of the invention 'tially flush with the panel.

about to be described, the air stream and the light beam are directed through a common aperture in a partition positioned within the casing, a. shield is positioned between the window and this partition, but to one side of the light beam, and translucent means adapted to be illuminated by the beam are positioned adjacent the window directly in the path of the beam. The translucent means serves as a pilot light adapted to indicate whether or not the light source is functioning. The pilot light may be rendered effective and ineffective at will by a shutter disposed between these means and the light source, which shutter is operable from the exterior of the casing. The air, in which smoke is to be detected, preferably, is introduced into the casing between the partition and the end wall of the casing having the window therein, and is Withdrawn from the casing at the opposite end thereof.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawing, forming a part of the specification, wherein:

Figure 1 is a front elevational view of a smoke detecting device in accordance with the invention.

Figure 2 is a sectional view taken along the line 2-2 on Figure 1, illustrating the interior of the device.

Figure 3 is a fragmentary sectional view taken along the line 3-3 on Figure 2, illustrating the shutter for controlling the pilot light.

Referring to the drawing in detail, there is shown a smoke detecting device generally com- "prising a casing I U, a. light source for providing a beam of light, such as a lamp II, and conduit means for passing an air stream through the light beam.

The casing It is generally rectangular, and has a front wall I2, a rear wall IS, a top wall III, a bottom wall I5, and side walls it. These walls may be so dimensioned to provide a casing which is small and compact to facilitate mounting the same on an instrument or control panel of a craft or vehicle with the front wall l2 being substan- In practice, it has been found feasible to utilize a casing which occupies less than thirty cubic inches of space.

The front wall I2 has a rectangular sight opening IT in the upper portion thereof, a transparent window 53 extending inwardly into the casing from the lower edge of the opening and a translucent button or disc I9 just below the opening, the purposeof which will be made apparent hereinafter.

A partition 20 is positioned in the casing between the front and rear walls thereof which preferably extends from the top to the bottom walls and from one side wall to the other, whereby the casing is divided into forward and rearward zones. The partition, as shown, has a lower vertical section 2i on which the lamp H is mounted atthe side within therearward casing zone, and has an upper, downwardly and rearwardly inclined section 22 formed with an aperture 23 which is in horizontal alignment with the opening IT.

The conduit means for circulating anair stream through the casing in which smoke is to be detected comprise a tube 24 extending through the rear wall i3 and the partition 2!} to the forward casing zone, and an openingin the rear wall hav ing a tube 25 in communication therewith. Preferably, the air is introduced through the tube 2/! into the forward zone, is passed through the aperture 23 in partition 22 to the rearward zone, and'is removed from the rearward zone through the'tube 25. h V

Theai'r stream in being so circulated passes through a beam of light adapted to illuminate smoke particles suspended in the stream. This light beam is provided by the lamp H and is directed through the partition aperture 23 by a reflector '26 mounted on the top wall it in the rearward zone. The reflector is so positioned that the light beam is directed substantially directly towards the opening I 'l but just below the lower side edge thereof whereby the center of the beam is directed on the center of the button i9. In'this manner, the light beam and air stream intersect each other, and the button is illuminated to ,the other sidewall of the casing. Thesebafiles depend from the top wall .of the casing-and are inclined downwardly and rearwardly substantially at the same angle as the partitionwhereby they are 'parallel'thereto. The bafiie 23 nearest the opening is longer than the baffie 29 and its lower edge is nearer to the center of thebeam" than that of the baffle 29. By being so arranged,

the shorter bafiie 28 blocks the light diffused ,upwardly at a wide angle and the longer baffie '28' blocks the stray light of the upper part of the beam which gets past the shorter bafile.

As shown herein, the inner edge of the window T8 is supported by suitable means adjacent the lower edge of the bailie 28, and is positioned substantially parallel to the light beam to minimize the reflection of stray light thereon from the interior of the casing. The forward end of the top wall 14 shields the window against reflection of stray light at the exterior of the casing.

When the interior of the casing is observed by looking through opening ll and the window 18, as indicated by the arrow A (Figure 2), the bafile 28 obscures the aperture 23. The line of vision thusis in general direction towards the origin of the beam but is oblique thereto whereby any illuminatedsmoke particles can be readily seen.

. sible.

This is accomplished with an extremely small and compact device by arranging the apertured partition, the bafiles, the opening and the window as shown.

While the provision of a pilot light is a desirable feature, it is also desirable that the instrument panel, particularly near thesmoke detecting observation window, be kept as dark as pos- Hence, it is contemplated that the pilot light should be visible only when it is desired to determine whether or not the lamp is in workmg order, and should be darkened at all other times. This is accomplished in a convenient manner by placing a movable shutter between the light beam and the button [9.

As shown in Figures 2 and 3, a shutter 30 in the form'of a segment of a circular disc is mounted on and is secured to a shaft 3| which is rotatably supported in a bushing 32 and extends outwardly through the front wall of the casing. The shutter has a slot 34 at one side thereof which permits the light beam to pass therethrou'gh' and be directed on the translucent button. The other or to the'left to block the beam and darken the button. A handle 39 is provided on the --shaft3l at the exterior of the casing for effecting .movement of the shutter, and cooperating indicia are provided on the front wall of the casing (Figure 1) to indicate the on and off pilot light positions 7 of'the shutter.

From the foregoing description, it will be seen that the present invention provides a simple, practical and economical visual smoke detecting device which is small and compact and lends itself for use in craft or vehicles where space is at a premium. The device is reliable inper .formance, and cannot get out of order during normal usage thereof, except for failure of the lamp which would be detected by the pilot light arrangement.

As various changes may be made in the form,

construction and arrangement of the parts hereinywithout departing from'the spirit and scope of the invention and without sacrificing any-of its advantages, it is to be understood tha-twall matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim: V 1. In apparatus for detecting suspended-mat- .ter in a'fluid, the combination of a casing :hav-

ing an upper wall and having a front wall adapted to constitute a portion of an instrument panel and being provided'with a sight opening, said casing having a window extending from about the lower edge of said opening inwardly into said-casing in a generally longitudinal direction with respect to said casing, a light source in said casing for providing a beam of light, means for directing the light beam towards the inner side of said front wall in a direction substantially parallel to saidwindow, opaque bafli'e m'eansfin said casing in the line'-of."vision between, said opening and said light beam "directing means,

and means for circulating a stream of fluid in which suspended matter is to be detected through said casing and through the light beam adjacent said window.

2. In apparatus for detecting suspended matter in a fluid, the combination of a casing having an upper wall and having a front wall adapted to constitute a portion of an instrument panel and being provided with a sight opening, said casing having a window extending from about the lower edge of said opening inwardly into said casing in a generally longitudinal direction with respect to said casing and having an opaque baffle wall extending from said window adjacent its inner end to said upper wall, a light source in said casing rearwardly disposed of said bafile wall for providing a beam of light, means for directing the light beam towards the inner side of said front wall in a direction substantially parallel to said window, and means for circulating a stream of fluid in which suspended matter is to be detected through said casing and through the light beam adjacent said window.

3. In apparatus for detecting suspended matter in a fluid, the combination of a casing having an upper wall and having a front wall adapted to constitute a portion of an instrument panel and being provided with a sight opening, said casing having a window extending from about the lower edge of said opening inwardly into said casing in a generally longitudinal direction with respect to said casing and having an opaque bafiie wall extending from said window adjacent its inner end to said upper wall, a partition in said casing having an aperture therein, a light source in said casing rearwardly disposed of said partition for providing a beam of light, means between said light source and said partition for directing the light beam through said partition aperture towards the inner side of said front wall in a direction substantially parallel to said window, and means for circulating a stream of fluid in which suspended matter is to be detected through said casing and through the light beam adjacent said window.

4. In apparatus for detecting suspended matter in a fluid, the combination of a casing having a rear wall an upper wall and having a front wall adapted to constitute a portion of an instrument panel and being provided with a sight opening, said casing having a window extending from about the lower edge of said opening inwardly into said casing in a generally longitudinal direction with respect to said casing and having an opaque bafiie wall extending from said window adjacent its inner end to said upper wall, a partition in said casing having an aperture therein, a light source in said casing rearwardly disposed of said partition for providing a beam of light, means between said light source and said partition for directing the light beam through said partition aperture towards the inner side of said front wall in a direction substantially parallel to said window, and means for circulating a stream of fluid in which suspended matter is to be detected through said casing and through the light beam adjacent said window, said last mentioned means including an inlet and an outlet in said rear wall and including a conduit in said casing connected to said inlet, and having an opening between said front wall and said partition.

5. In apparatus for detecting suspended matter in a fluid. the combination of a casing having a front wall provided with a sight opening, said casing having a window extending from about the lower edge of said opening inwardly into said casing in a generally longitudinal direction with respect to said casing, translucent means in said wall adjacently below said window, means for circulating a stream of fluid in which suspended matter is to be detected through said casing and through a zone adjacently below said window, a light source in said casing providing a beam of light, means for directing the beam of light sub stantially parallel to said window and through said zone and directly on said translucent means, a shutter in said casing adapted to be positioned between said translucent means and said light beam directed on said translucent means, and means for operating said shutter from the exterior of said front wall.

6. In apparatus for detecting suspended matter in a fluid, the combination of a casing having an upper wall and having a front wall adapted to constitute a portion of an instrument panel and being provided with a sight opening, said casing having a window extending from about the lower edge of said opening inwardly into said casing in a generally longitudinal direction with respect to said casing, translucent means in said wall adjacently below said window, a light source in said casing for providing a beam of light, means for directing the light beam towards the inner side of said front wall in a direction substantially parallel to said window and directly on sai translucent means, opaque bafile means in said casing in the line of vision between said opening and said light beam directing means, and means for circulating a stream of fluid in which suspended matter is to be detected through said casing and through the light beam adjacent said window.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,012,230 Grant Aug. 20, 1935 2,283,769 Schwanzel May 19, 1942 2,356,238 Gillett et a1 Aug. 22, 1944 2,485,588 Grant Oct. 25, 1949

Images