US2738159A - Valve - Google Patents

Description

March 13, 1956 2,738,159

W. T. FLEMING v VALVE Filed June 30, 1951 T 30 2/ 24 35, J54 I 32 INVE TOR. Wallzam Z'F emmy BY ATTOR1VY United States Patent VALVE William T. Fleming, West Orange, N. J assignor to Sp ecialfies Development Corporation, Belleville, N. 3., a corporation of New Jersey Application June 30, 1951, Serial No. 234,533 4 Claims. (Cl. 251-333 The present invention relates to valves, and, more particularly, to valves for controlling the flow of dry powder during discharge thereof, for example, from a fire extinguisher.

Dry powder fire extinguishing agents comprising essentially sodium bicarbonate or some similar material are used extensively at the present time for combating various types of fires. In many instances, it is desirable that the apparatus be in the form of a portable extinguisher containing a pressurized charge of powder in sufiicient quantity to extinguish several fires so that the extinguisher can be used several times before it is necessary to recharge the same.

In order to accomplish the foregoing, the discharge outlet of the extinguisher preferably is controlled by a seat type valve because such valves are simple in construction, are economical to manufacture, can be so designed to eliminate passageway contours which might interfere with the free flow of the powder therethrough, and can be arranged to reseat under the influence of the pressurizing medium in the extinguisher.

However, one of the difficulties encountered in connection with the use of a seat type valve for controlling the flow of pressurized powder is that, once the valve has been opened and powder is discharged therethrough, the powder contaminates the seat and/or the valve member, whereby, upon reclosing of the valve, the powder be tween the seat and the valve member prevents the reestablishment of a pressure-tight seal. Consequently, over a short period of time, the pressurizing medium leaks through the valve, whereby, when it is desired to use the extinguisher a second time, the powder is insufficiently pressurized to effect discharge thereof. A similar diificulty may be encountered in the event the extinguisher is carelessly charged and powder is deposited on the seat or the valve member whereby an inefiective seal is provided and the extinguisher will not function even the first time it is used.

The foregoing is a very serious matter because the inabilityof the extinguisher to function is only discovered at the outbreak of a fire, and, before another extinguisher can be brought to the location of the fire, the fire may have gained considerable headway and may have gotten out of control, whereby a heavy fire loss occurs which could have been averted had the extinguisher functioned properly.

Accordingly, an object of the present invention is to provide an improved seat type valve suitable for controlling the discharge of pressurized dry powder at spaced intervals without being subject to the foregoing difiiculties.

Another object is to provide a valve of the character described herein which is extremely simple in design, is economical to manufacture, and enables dry powder to flow freely therethrough upon opening thereof.

A further object is to provide a valve of the foregoing type which is self cleaning in that powder particles cannot become lodged between the seat and the valve Patented Mar. 13, 1956 member, whereby a pressure-tight seal is formed upon reclosing of the valve, which seal is effective to confine the pressurizing medium.

Other and further objects of the invention will 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 ernployment of the invention in practice.

In accordance with the invention, the foregoing objects are accomplished by providing a valve comprising a casing having a port therein, a seat member formed of yieldable rubber-like material having an opening therethrough coaxially positioned adjacent the port, and a valve member having a rigid frustoconical section adapted to extend into the opening and engage the seat member, the opening being tapered axially inwardly in a direction away from the port and the valve member section being tapered axially inwardly in a direction toward the port.

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 view of the upper portion of a dry powder extinguisher or similar dry powder dispensing apparatus, partly in elevation and partly in section, illustrating the valve in accordance with the invention.

Figure 2 is an enlarged fragmentary view of the valve seat and the valve member, the valve member being shown in unseated position to illustrate the normal shape of the valve seat.

Figure 3 is a view similar to that of Figure 2, the valve member being shown in seated position to illustrate the shape that the valve seat assumes when engaged by the valve member.

Referring to the drawing in detail and more particularly to Figure 1 thereof, there is shown apparatus for dispensing dry powder, such as a manually carryable fire extinguisher. This apparatus generally comprises a container 10 adapted for storing dry powder having a closed end wall at the bottom thereof (not shown) and having an outlet spud 11 at the upper end thereof, a valve casing 12 secured to the spud having a passageway extending therethrough provided with an inlet and an outlet, at syphon tube 14 extending from the inlet to adjacent the bottom of the container for conducting the powder to the valve casing passageway, a discharge born or shield 15 connected to the outlet of the passageway for directing the powder discharged from the container, a pistol grip type carrying handle 16 secured to the valve casing, a trigger-type operating lever 17 partially housed by the handle and pivotally mounted at 18 on a lug 19 of the valve casing for effecting opening of the valve about to be described, and spring means 20 for normally biasing the lever into a position to close the valve.

The apparatus just described is charged by first placing a desired quantity of dry powder in the container 10, for example, while the valve casing 12 is disconnected from the spud 11, connecting the valve casing to the spud as shown herein, and then introducing a pressurizing medium such as nitrogen into the container to provide a pressure head of about 200 to 300 pounds per square inch which is effective to push the powder upwardly through coaxial alignment with the port, a valve member 26 is adapted to extend upwardly into the opening and engage the seat member to close thevalve, and a valve stem 27 has its lower end secured to the upper end of the valve member and has its upper end operatively connected to one arm of the lever 17 at 28, whereby the lever is adapted to effect opening of the valve upon manual operation thereof and is adapted to effect closing thereof under the influence of the spring means 2t).

in accordance with the invention and as shown more particularly in Figures 2 and 3, the seat member 24 is annular in shape and the opening 25 is generally circular. This member is formed of slightly yieldable rubber-like material such as synthetic rubber, preferably, for example, Rodic rubber, a product of Rodic Rubber Corporation, New Brunswick, N. 1., which is a Buna-N- phenol formaldehyde type rubber material, or similar rubber materials having an A scale durometer hardness of between about 87 and 93. The surface of the seat member providing the opening is tapered inwardly in a direction away from the port 22, that is downwardly and radially inwardly as viewed, whereby the opening is frusto conical in shape. As will be observed, the opening 25 is in coaxial alignment with the port, and the port has a greater cross-sectional area than the maximum cross-sectional area of the opening, that is, the diameter of the port is greater than the diameter of the upper portion of the opening, whereby an annular zone 30 of the seat member extends inwardly of the port and is unsupported by the shoulder section 21. Preferably, the seat member has a thickness between about 6 and about times as great as the radial width of this annular zone.

Further, in accordance with the invention, the valve member 26 has a frusto-conical section 31 formed of rigid material such as metal or hard synthetic plastic material. The surface of this section is smooth and is tapered inwardly in a direction toward the port 22, that is upwardly and radially inwardly as viewed. As will be observed, the valve member is in coaxial alignment with the seat opening and the port.

It has been found that maximum cooperation between the valve seat 24 and the valve member 26 to form a pressure tight seal is achieved, by providing the surface of the opening 25 with a taper of about 10 and by providing the surface of the section 31 with a taper of about 8 with respect to the vertical axis of the valve member.

In Figure 2, the valve seat and valve member are shown in detail with the valve member unseated or in valve passageway opening position whereby the normal shape of the valve seat as just described will become apparent.

in Figure 3, these elements are again shown, but with the valve member engaging the valve seat in valve passageway closing position. When the valve member first engages the seat, it is biased thereagainst under the influence of the spring means and the pressurizing medium in the container and moves with respect to the seat member a short distance. This relative movement effects a wiping action between the surfaces of the opening and the valve member section 31 which serves to remove powder particles between these engaging surfaces to prepare for a gas tight seal. In the final position of engagement between these surfaces, as shown in Figure 3, the lower inner portion of the seat member is deformed into an annular depending lip or wedge portion 32 which provides an annular zone of'engagement 34 of considerable \vidth whereby an effective pressure type seal is attained between the wiped surfaces. Also, by reason of the lower inner annular portion of the seat member being arranged to extend radially inwardly of the port, the pressurizing medium in the container acts on the yieldable lip or wedge portion 32 to urge the same inwardly against the valve member thereby providing for further cooperation between the valve member and the seat member to form a seal of maximum efiiciency.

The improved seal as just described is provided both when the apparatus is initially charged and when the valve passageway has been opened to effect discharge and thereafter reclosed before the entire contents of the container have been discharged.

it is also contemplated that the degree of compression of the valve seat member 24 against the shoulder 21 be uniform in each valve and of a predetermined value. To accomplish this, a retainer ring 35 is positioned in the valve casing which has an annular shelf 36 for supporting the valve seat member and has an annular rim 37 surrounding the valve seat member. The rim projects upwardly from the shelf a distance slightly less than the thickness of the valve seat member and is adapted to engage the shoulder 21 when the ring 35 is urged upwardly by means such as a screw ring 33 threaded into the valve casing (Figure 1), whereby the valve seat membet is slightly compressed between the shelf and the shoulder. Since the thickness of the valve seat member and the height of the rim can be accurately maintained uniform in the manufacture of these parts, a predetermined degree of compression of the valve seat member is effected when the rim contacts the shoulder. Preferably, the valve seat member is compressed only slightly, for example ten percent or less, to hold it firmly in place without material distortion thereof. By so controlling the compression of the valve seat member, its cooperation with the valve member 26 will be exactly the same in every instance.

As shown herein, the ring 35 has an annular, generally conical surface 49 at its underside which is inclined upwardly and outwardly, the screw ring 38 has an annular, generally conical surface 41 similarly inclined; and the upper end of the syphon tube 14 has an upwardly and outwardly inclined flange 42 positioned between the surfaces 40 and 41. The screw ring 38 in this manner serves to mount the syphon tube and, through the surfaces 40 and 41 and the flange 42, to wedge the ring 35 upwardly and apply the desired pressure on the seat member 24.

While the valve in accordance with the present invention has been described herein as being particularly adapted for controlling the discharge of dry powder, it will be apparent that the valve may be used advantageously for controlling the discharge of other liquid or fluid material under pressure.

From the foregoing description, it will be seen that the present invention provides a simple, practical valve for controlling the discharge of various material under pressure which eliminates leakage of the material or the pressurizing medium from the container. The valve can be operated many thousands of times without loss of effectiveness of the seal provided by it, or wear or breakdown of parts which might otherwise impair the effectiveness of such seal.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. A valve comprising a body having an annular downwardly facing shoulder section provided with a circular port; an annular valve seat member formed of slightly yieldable rubber-like material having one side positioned against said shoulder section and being provided with a generally conical opening tapered downwardly at an angle of about 10; a retainer ring engaging the other side of said seat member to maintain the same against said shoulder section and being formed with an aperture; said port, said opening and said aperture being in coaxial alignment and said opening at said port having a smaller diameter than the diameter of said port at said opening and said aperture having a greater diameter than the diameter of said port at said opening to provide unsupported annular seat member zones at the upper and lower ends of said opening; and a valve member having a rigid frusto-conical section tapered upwardly at an angle of about 8 and adapted to extend into said opening and engage said lower annular seat member zone, said valve member and said seat member being characterized in that said valve member section upon engaging said seat member moves said upper annular seat member zone towards said port and deforms said lower annular seat member zone to provide an annular depending lip surrounding said valve member section and engaging the same throughout an annular zone a considerable width.

2. A valve according to claim 1, wherein said seat member has a thickness between about six and about ten times as great as the radial width of said upper unsupported annular zone thereof.

3. A valve according to claim 1, wherein said seat memher has a durometer hardness of between about 87 and about 93.

4. A valve according to claim 1, wherein said retainer ring is screw threadedly secured within said valve body to effect compression of said valve seat member.

References Cited in the file of this patent UNITED STATES PATENTS 1,899,154 Karrick Feb. 28, 1933 1,971,013 Mesinger Aug. 21, 1934 2,057,150 Kehl Oct. 13, I936 2,073,112 Lindinger Mar. 9, 1937 2,105,487 Lozon Jan. 18, 1938 2,299,073 Beasley Oct. 20, 1942 2,510,861 Boal June 6, 1950 2,548,750 Stroop Apr. 10, 1951

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