US2668284A - Apparatus for detecting suspended matter in fluids - Google Patents

Description

Feb. 2, 1954 DfMAPES 8 APPARATUS FOR DETECTING SUSPENDED MATTER IN FLUIDS Filed Feb. 28, 1950 56 INVENTOR.

Davu/ Mapes ATTORNEY Patented Feb. 2, 1954 ARBAEA'EUSL EQR; DE CT NG snsnnnnrn:

MATTER IN FLUIDS.

Daniel; lid'apes, West Oaldwell', N; J'., assignor to Specialties Development ()orporation, Belleville, N. J;, a corporation of New Jersey Appli ati n Feb uarx 2 lildllrfie ial cs fififi' d 5 Claims. 1

This invention. relatesto apparatus, for detect.- ing, the presence oi. suspended matter fluids and is particularly directedto apparatus for detecting. the presence of smoke in; air due. to the outbreak. of fire in a protected. space or compart ment and for determining. the density of the smoketherein.

Morev specifically, the presentimlention relates toismokedetectors wherein the resence oi smoke in; air drawn from. a. protected.- space is detected and an alarm given.

The present invention can be utilized with; any type smoke detector wherein an electric. current changes in value: relative. chang t density of they smoke to be detected. Such. deteotors. include. the photoelectri cell types; the thermocouple type, or. any other-type which depends for its operation upon electric current changes effected by. smoke densitychanges. In some of such ypes of det tors, the curr n hange results inan increas fthe current, while in. othersthe change r sults in a decr a e f th current,

For. purposes. of illustration and descript on only, nd without limiting the present invention thereto, a photoelectric cell. t pe sm ke. detec or willhe referred to. herein, In. such detectors, the presence of smoke in air drawn from the protected. space. is detected by the photoelectric ce and an alarm given.

It. is known that. the conc ntrati n of smoke in a compartment. in which a fire exi s does no remain static, but gener lly increases as the fire pro resses and ecreases.- as the fire subsid s. bu it is. difiicult and. sometimes. impossi le to obs rv the concentration of; smoke, and. its. increase and decrease, inv inaccessible compartments and enclosures.

In. smoke. detectors of. he. character indicated, such as employed to protect inaccessible corn- Dartments in an airplane, air continuously drawn through a detector tube having. a light source at one end and a photoelectric cell at the opposite end in the path of rays of light from the light source. electric cell result in the generation of current in the photoelectric cellcircuit, which is provided with a relay to effect the giving of an. alarm when the intensity of: the light rays. is decreased. When he air, which is continuously drawn throu h the e ctor ube n o the path of he li ht raysocntaihs smoke, the intensity of.- the light rays is decreased, Whereby the alarm is transmitted to a s gnal device on the instrument. panel-hi. th plane, whereupon the pilot or observer op rates The light rays fallingon the photo- 3 afili extinguishing system todischarge fire eigtinguishing medium into the protected space or .Bar inent; Wel

invention applie compartment.

Wit suc y ems t has been the practic of the pilot or observer to personally inspect the protected space. after the discharge of the fire extinguishing medium to determine whether or not the; fire has been extinguished. However, in inaccessi e. sp es. r ompar me s irplane p sonal nsp c is. o alway po sible nflish i. a a a ul it c ui ot. or bser er. is unable to determine. when the fire has, been egrtinguished; 7

lso. w th s h. ys em raise a a ms are. t naim s. t nsm t d due to th pre nter dustin the d tect r tube. or due o some clectri aidisu ba c o oth r cause, Whe ther iore. alarm is. tran m tted ,t .l pilo or obse ver canno determine whether it is a false. alarm or it is due to he. utbre k of. fi e; ireextine i e ium s rel ased. nto the space or. om: oa ment y he. lot or ohse e i resu t ng v in th a e. of a false in t e wastins oi x g i ng, medium. and nnecess ry concer d'ccniu on. 1

cc rd ngl t icons o t e qhiects oi he r snt inven on to proride. im roveddeteotms app r s, whe eby up n recei in a fire ala e P l or bse ver ca r adily de rmin Whether the alar is th result o fire or s a false alarrn,

Anothe ob ector the. intention. res des i th p ov si oi? detecting. appa atus, wherein alte re inguishing. medium is discharged into. h Pr e ted comnartine t or space t e pil t or observer can readily determine. without a personal nsp ct n, of. he. compar ment, Whethor'the fire has be n en ineuished o s stil n orosrcss Anothe objectresides in h pro i ion of ead y operable. r. det minin he density or concen ration r smoke in. he co as any in rease de re se in such. cpno n rat nr ther and; iu thcr obj cts of he present v n 'cn wil he obviou m he i lowins. s ecifi c tion and the ccompanying. drawina. wherei Preiierred embod rnen s or. theinvcntion a e d scribed..andi lhstrat d 1 In he drawing;

figu e 1 is a di r mmatic illustration o th to. a detec or tube. oi h ingl illust ation o t e nvention applied to a alanced photoelec ric ell t p de ector; a d

Figures 3 and 4 are diagrammatic illustrations of modified forms of the invention.

Referring to the drawing in detail, a detector tube I is shown having a detector lamp l2, constituting a light source, mounted in one end of the tube and connected to a source of current supply M. A lens I6 is also mounted adjacent the light source, and a photoelectric cell i8 is mounted in the opposite end of the tube in the path of direct rays of light from the detector lamp. The tube has an air inlet 2!] and an air outlet 22. A suction device or blower 24 is provided for drawing air from a protected space or compartment, which is in communication with the inlet and thence through the tube from the inlet to the outlet.

When smoke is present in the air drawn through the detector tube, and consequently into the path of the rays of light falling on the photoelectric cell, the intensity of the light rays is reduced, thereby resulting in a reduction of the current flowing in the photoelectric cell circuit.

A relay 26, connected in the photoelectric cell circuit, has a pointer or switch arm 28, which is in balanced position while a normal current is flowing in the photoelectric cell circuit. When the current output of the photoelectric cell falls to a predetermined value below normal, the arm 28 moves to the right, as viewed in Figure 1, into engagement with a contact 3 9. An alarm circuit is connected to the relay, so that when the arm 28 engages the contact 30 the alarm circuit is established from a source of current supply, such as a battery 32, through the relay to an alarmi-M. The relay 26 is preset to close the alarm circuit upon a predetermined drop in the current output of the photoelectric cell, and accordingly cannot give graduated readings beyond the preset point.

A manually operable switch 36 is provided in line 38 of the photoelectric cell circuit, where by the relay may be disconnected from the photoelectric cell circuit and a smoke density indicating meter 46 of sufiicient range shunted into the circuit when the switch 36 is moved out of engagement with the contact 42 and into engagement with a contact 44.

The switch 36 may be a push button or switch lever conveniently located on the instrument panel of the airplane within easy reach of the ilot or observer, so that, when an alarm is given, the pilot or observer may press the button or throw the lever to disconnect the relay 25 from the photoelectric cell circuit, interrupt the alarm circuit, and connect the smoke density meter into the photoelectric cell circuit.

The smoke density indicating meter has the usual pointer M and a relatively long scale 43, so that when it is connected into the photoelectric circuit, in the manner just described, the pilot or observer can readily determine the density of the smoke in the smoke detector tube and observe changes in the density or concentration of the smoke, whereby to determine the condition of the fire. Should the meter show an increasing smoke concentration, it will be an indication that the fire is still in progress, while a decreasing concentration will be an indication that the fire is subsiding. Should the meter show zero concentration, it will be an indication that the fire has been extinguished. If, after a reading showing zero concentration, the smoke density indicating meter should again show an increase in the concentration, it would be an indication that the fire has reignited. Should the meter reading remain static, it will be an indication that the alarm was a false alarm due to the presence of dust in the air or on the lens, detector lamp or photoelectric cell, or due to some electrical disturbance.

The illustration of Figure 2 is somewhat similar to that of Figure 1, except that it shows the present invention applied to a smoke detector of the balanced photoelectric cell type. The operation of the detector and indicating means of Figure 2 is the same as that of Figure 1 and the same reference numerals have been applied to corresponding parts in the two forms.

In the modification shown in Figure 3 the relay 25 and the smoke density indicating meter Ail are connected in series in the photoelectric cell circuit. In this form, when no smoke is present in the detector tube Hi, the arm 28 of the relay and the pointer 4! of the meter are in the positions illustrated. When smoke is drawn into the tube It and the current generated by the photoelectric cell drops to a predetermined value, the contact arm 28 of the relay 26 will move into engagement with the contact 39 thereof whereby to close the alarm circuit, and at the same time the pointer M of the meter will move across the scale 43 whereby to indicate the degree of density of the smoke in the tube it. The observer can readily determine from the action of the pointer 4! whether the alarm is true or false, and if true, he can readily observe the condition of the fire, as determined by the indicated changes in the density.

In the modification shown in Figure 4, a single relay or meter 48 is illustrated, which serves the dual function of the relay 26 and the indicating density meter 40 of Figures 1 and 2. In this form the full scale of the meter is employed. The relay has a plurality of shunt resistors, in series with a normally open switch, connected across its coil, each having a resistance which is a multiple of the resistance of the relay coil. By way of example, the shunt resistor 50, when connected across the coil may have a resistance the multiple of two so that when it is connected across the coil it doubles the range of the relay, the shunt resister 52 may have a resistance the multiple of three so that it will triple the range of the relay when connected across the coil, and the shunt resistor 54 may have a resistance the multiple of four, so that it will quadruple the range of the relay. Any desired number of resistances may be employed, each being adapted to be manually selectively connected into the relay circuit, by merely closing a switch 56 of the selected shunt resistor, after a signal is given by reason of the arm 28 engaging the contact 3!], in the manner described in connection with the other forms. When the proper resistance is cut into the circuit to efiect the return of the contact arm 28 or the separation of that arm from the contact 30, that arm will thereafter operate, in the same manner as the meter 40, to indicate the density of the smoke in the detector tube II).

It is well known that smoke detectors are adversely affected by voltage variations, and it has been the practice to provide a voltage regulator or equivalent compensator to accommodate the detector to such variations. It is to be understood that the detector of the present invention may be provided with such a regulator or compensator, inasmuch as the provision thereof does not constitute part of the present invention. Also, it is to be understood that a conventional amplifier may be provided in the photoelectric cell circuit.

From the foregoing it will be seen that the present invention provides a detector wherein the progress or retardation of fire in a protected space or compartment can be observed from a point remote from the space or compartment, and wherein false fire alarms can readily be detected.

While I have illustrated and described preferred embodiments of my invention, it is to be understood that I do not wish to be limited to the precise structure and arrangement of parts as described and illustrated, as obviously various changes and modifications may be made therein without departing from the spirit and scope of my invention.

I claim:

1. In smoke detecting apparatus of the class described, the combination of a source of light, an electric circuit therefor, a second electric circuit, means responsive to variations in the intensity of the rays of light from said source to effect changes in the current flowing in said second circuit, means for interposing a stream of air in which smoke is to be detected in the path of said light rays to effect variations in the intensity thereof, electroresponsive means in said second circuit operable upon the presence of smoke in the path of said rays, signal means, a

circuit for said signal means including switch means operable by said electroresponsive means adapted to be closed to operate the signal means upon the operation of said electroresponsive means, a smoke density indicator in paid second circuit and means operable to render said electroresponsive means ineffective and said indicator operable to effect an indication of the density of the smoke and changes therein.

2. In smoke detecting apparatus of the class described, the combination of a source of light, an electric circuit therefor, a second electric circuit, means responsive to variations in the intensity of the rays of light from said source to effect changes in the current flowing in said second circuit, means for interposing a stream of air in which smoke is to be detected in the path of said light rays to effect variations in the intensity thereof, electroresponsive means in said second circuit operable upon the presence of smoke in the path of said rays, signal means, a circuit for said signal means including switch means operable by said electroresponsive means adapted to be closed to operate the signal means upon the operation of said electroresponsive means, a smoke density indicator in said second circuit, and manually operable switch means in second circuit to render said electroresponsive means ineffective and said indicator operable to effect an indication of the density of the smoke and changes therein.

3. In smoke detecting apparatus of the class described, the combination of a source of light, a circuit, means responsive to rays of light from said source to generate electric current in said circuit, means for interposing a stream of air in which smoke is to be detected in the path of said rays, a relay connected in said circuit operable upon the presence of smoke in the path of said rays, signal means, a circuit for said signal means adapted to be closed to operate the signal means upon the operation of said relay, a smoke density meter, and means operable to disconnect said relay from said first mentioned circuit and connect the smoke density meter into the circuit, whereby to indicate the density of the smoke and changes therein.

4. In smoke detecting apparatus of the class described, the combination of a source of light, a circuit, means responsive to rays of light from said source to generate electric current in said circuit, means for interposing a stream of air in which smoke is to be detected in the path of said rays, a relay connected in said circuit operable upon the presence of smoke in the path of said rays, signal means, a circuit for said signal means adapted to be closed to operate the signal means upon the operation of said relay, a smoke density meter, and manually operable means for disconnecting said relay from said first mentioned circuit and connecting the smoke density meter into that circuit, whereby to indicate the density of the smoke and changes therein.

5. In smoke detecting apparatus of the class described, the combination of a source of light, a circuit, means responsive to rays of light from said source to generate electric current in said circuit, means for interposing a stream of air in which smoke is to be detected in the path of said rays, a relay connected in said circuit operable upon the presence of smoke in the path of said rays and having a switch arm and a contact in the path of said arm, signal means, a circuit for said signal means including said switch arm and contact adapted to be closed to operate the signal means upon the operation of said relay, a smoke density meter, and manually operable means for disconnecting said relay from said first mentioned circuit and connecting the smoke density meter into that circuit, whereby to indicate the density of the smoke and changes therein.

DANIEL MAPES.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 880,273 Bristol Feb. 25, 1908 1,487,898 Stolp Mar. 25, '1924 1,728,929 Ernst et a1. Sept. 24, 1929 2,248,047 Addy et al. July 8, 1941 2,301,367 Cahusac et a1 Nov. 10, 1942

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