US2386412A - Liquid detecting means - Google Patents

Description

Oct. 9, 1945. R. E. B. WAKEFIELD LIQUID DETECTING MEANS Filed April' 28, 1942 INVENTOR /P/cf/ARD E. B. M/HA/fF/fzo LL-ENE.

'l I ATTORNEY Patented Oct. 9, 1945 LIQUID DETECTING MEANS Richard E. B. IVakeeld, Aldan, Pa., assignor to Selas Corporation of America, a corporation of Pennsylvania Application. April 28, 1942, Serial No. 440,780

(Cl. 7S-40) 8 Claims.

The primary object of the present invention is to provide simple and elective means for detecting the presence of liquid, and more particularly is concerned with an improvement for detecting the presence of gasoline ina chamber or space in which the presence of such gasoline is dangerous and undesirable. Although not to be limited thereto, the invention. was devised for use as a safety device in gasoline burning heatersv used in war planes to heat cabin or compartment spaces, ammunition, guns and machinery and for other heating purposes.

More specic objects of the invention are to provide a gasoline detector adapted for the war plane use specied, and characterized by its mechanical simplicity and operative reliability, its small bulk and weight, and the ease with which it can be restored to the condition in which it is again adapted to respond to the presence of gasoline after having been put out of that condition by a previous response.

The present invention is characterized primarily by the use of adhesive material which normally restrains the opera-tion' of a resilient element but which when wet with gasoline releases said element and thereby effects a safety action such as the actuation of a signal or a heater control switch.r

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages, and specific objects attained with its use', reference should be had to the accompanying drawing and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

Of the drawing: JFig. 1 is an elevation partly in section of a gasoline burning airplane heater;

Fig. 2 is a. section on the line; 2-2' of Fig. 1l ilits lower portion, to which combustion air and entrained gasoline in an atomized condition is passed by a fan C when the heater is in operation. The ian C is of the turbo blower type and is driven by a high speed electric motor element D. Combustion air is drawn into the casing of the fan C by the rotation of the fan through an inlet duct E extending horizontally away from the center of the heater to the periphery of the latter and having an uprising inlet portion E including a nre check.

The gasoline burned in the heater is supplied through a nozzle F, which, as shown, has a restricted outlet F through which the gasoline is discharged in the form of a jet impinging on the central portion of the fan C. The latter thus serves as a mechanical atomizer. Ordinarily, gasoline is supplied to the nozzle F under a pressure of ve or six pounds or so. As shown, a solenoid valve F2 in the pipe supplying gasoline to the nozzle F, is energized and open, or deenergized and closed, t0 permit or prevent the passage of gasoline to the nozzle F.

There is some risk of an accumulation of liquid gasoline in the duct or channel E as a result of a failure in the heater ignition means or other accidental injury to the heating system, or as a result of leakage past the valve F2 during an eX- tended period of non-use of the heating system. Any considerable accumulation of gasoline in that duct E will create a seriousl lire and explosion risk. That risk is eliminated or substantially minimized in accordance with the present invention, by the use of a gasoline detector G.

As shown, the detector G comprises a chambered bodygattached to the wall of the channel E, adjacent the outer end of the horizontal portion thereof and formed with a lower gasoline well G1 and an upper switch chamber G2. The well G1 is in communication through a port G4 with the horizontal lower portion of the conduit E so that gasoline tending to accumulate in the conduit E` will drain into the well G1. The bottom wall of the latter is formed by a threaded plug G3 screwed into the lower end of and removable from the well G and formed with a cavity or recess in its upper side which normally receives a detector element H. The latter is adapted to elongate when wetted with gasoline, and thereby actuate a control switch J mounted in the switch chamber G2.

In the preferred construction shown, the elongation of the element H raises a plunger I which extends loosely through an aperture in the horizontal top wall between the chambers G and G2 and -is adapted on the elongation of the element H, to engage and raise the actuating element J of the swtich J. Advantageously, the switch J is a snap action switch which when actuated by the element H cannot be restored to its previous condition except by a positive resetting operation. The switch J may thus be reset by finger pressure applied to a button J2. While the switch J desirably has the characteristics just mentioned, that switch of itself includes nothing novel with me and as shown the switch J is a snap action switch of the commercial type which is known as the Micro switch and is well adapted for its use illustrated in the drawing, because of its reliability in operation, its small bulk and weight, and the small and easily effected movements of the parts J and J2 necessary to actuate and reset the switch. Y

In the preferred construction illustrated, the element H comprises two metal parts h of cup or thimble shape and having their rims in juxtaposed relation. In the normal assembled condition of the element shown in Fig. 3, the two parts h are secured together with their rims in engagement by a strip of adhesive tape h wound about the cylindrical body formed by the peripheral walls of the two parts h. The latter may advantageously have their cylindrical surfaces corrugated or otherwise roughened to increase the strength of the bond between each of the parts h and the adhesive tape h. A helical spring h2 within the end to end parts h, is put under compression when said parts are brought into rim to rim engagement and is adapted to separate the parts h and thus elongate the element H and raise the switch actuating part I, when the connecting bond between the parts h formed by the adhesive tape h is suitably weakened. That bond is weakened to releive the spring h2 almost immediately, i. e. within 3 seconds or so, after the adhesive tape h is wetted by gasoline.

The actuation of the switch J, effected by the elongation of the element H, may actuate a signal or a heater control element or other safety means as conditions make desirable. For example, as shown diagrammatically in Fig. 4, the elevation of the switch part J may open a control circuit and-thereby close or prevent the opening of the solenoid gasoline valve F2 and interrupt or prevent the operation of the heater motor D.

In Fig. 4, the switch J is diagrammatically illustrated as comprising a plunger, of which the part J and button J2 form lower and upper ends, which is movable between upper and lower positions in each of which a spring K tends to retain the plunger. When the said plunger is moved upward as a result of the elongation of the element H, it separates a pair of spring contacts L in the heater energizing circuit, which includes the windings of the solenoid valve F2 and motor D and also includes a manually operable control switch M, by which the operation of the heater is normally controlled.

When gasoline wetting f the tape h causes the adhesive agent to soften and dissolve and results in the elongation of the element H, the latter is temporarily rendered inoperative for reuse. However, it can be restored to its normal operative condition by the simple expedient of replacing the gasoline wetted adhesive tape by fresh adhesive tape h', while holding the parts h in engagement with one another. The restoration of the element H to operative condition may be facilitated by the use ofa bolt N extending axially through the element H with its head in engagement with its one part h and carrying a nut N in engagement with the other part h. Such a bolt N with its nut N' forms a convenient appliance for use in holding the parts h in engagement While a fresh piece of adhesive tape is put in place and caused to adhere to the parts h.

The adhesive tape h Vmay, take various available forms. In an especially desirable form it consists of gauze having a relatively open weave saturated with latex which when pressed into contact with itself will adhere. When this saturated gauze is wound about the externally corrugated or threaded parts h, the threads of the gauze sink into the valleys between external ribs of the parts h and thus increases the strength of the bond formed by the tape. merely extended into adhesive material coating the tape, they would tend to shear away the adhesive material in a short time under the force due to the spring h2. The latex remains effective under summer temperatures. l

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from'the spirit and scope of my invention, as set forth in the following claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: i

1. A gasoline detector element comprising a pair of hollow externally ribbed parts, loosely woven gauze saturated with latex and wound about said parts and forming a bond normally operative to hold said parts against a relative movement of separation and being rendered inoperative to so hold said parts when wetted by gasoline, and a spring enclosed by said parts and operative to move them 'apart when said bond is rendered inoperative.

2. A liquid detector element comprising two relatively movable parts, means to bias said parts for relative movement, and bonding means including an adhesive agent having its adhesive properties impaired by contact with said liquid and normally maintaining an adhesive bond con- -nection between said parts to hold them against relative movement but rendered inoperative when said bond is wetted with said liquid.

3. A gasoline detector element comprising two relatively movable parts, means to bias said parts for relative movement, and flexible sheet material coated with an adhesive material having its adhesive properties impaired by contact with gasoline normally operative to maintain an adhesive bond connection between said parts to hold them against relative movement but rendered inoperative to maintain said bond connection when wetted with gasoline'.

4. A gasoline detecting element comprising a pair of hollow parts arranged end to end, a spring enclosed by said parts which tends to separate the latter, means normally connecting said members and holding them against relative movement under the action of said spring comprising flexible sheet material coated with an adhesive Inaterial soluble in gasoline and wrapped about said parts and normally maintaining an adhesive bond connection between said material and each of said parts. c

5. Apparatus for detecting the presence ofja If the ribs on the parts h" liquid comprising two relatively movable parts, resilient means operable to cause relative movement of said parts, and means for holding said parts together and render said resilient means ineffective, said holding means including material overlying said parts and containing an adhesive bonding agent intimately contacting said parts, said bonding agent possessing such properties that it softens when wetted by liquid of the kind Whose presence is to be detected, said holding means losing its ability to render said resilient means ineiective when said agent is sufficiently softened by saidy liquid.

6. Apparatus for detecting the presence of a liquid comprising two relatively movable parts, resilient means operable to cause relative movement of said parts, and means for holding said parts together and render said resilient means ineffective, said holding means including material overlying at least one of said parts which is impregnated with an adhesive bonding agent intimately contacting at least said' one part, said bonding agent possessing such properties that it tends to dissolve when wetted by liquid of the kind whose presence is to be detected, said holding means losing its ability to render said resilient means ineilective when said agent is acted upon sufficiently by said liquid.

7. Apparatus for detecting the presence of a liquid comprising two relatively movable parts, biasing means operable to cause relative movement of said parts, and means for holding said parts together and render said biasing means ineffective, said holding means including an adhesive bonding agent intimately contacting at least one of said parts and possessing such properties that it tends to dissolve when wetted by liquid of the kind whose presence is to be detected, said holding means losing its ability to render said biasing means ineffective when said agent is acted upon sufiiciently by said liquid.

8. Apparatus for detecting the presence of a liquid comprising two relatively movable parts having uneven surface portions, resilient means operable to cause relative movement of said parts, and means for holding said parts together and render said' resilient means ineffective, said holding means including open weave material in intimate contact with said uneven surface portions which is impregnated with an adhesive bonding agent possessing such properties that it tends to dissolve when wetted by liquid of the kind whose presence is to be detected, said holding means losing its ability to render said resilient means ineiective when said agent is acted upon suciently by said liquid.

RICHARD E. B. WAKEFIELD.

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