US2950728A - Flapper valve - Google Patents

Description

R. B. WATROU S FLAPPER VALVE Aug. 30, 1960 Filed Dec. 3, 1954 FIG.

FIG. 3

INVENTOR 7 ROBERT B. WATROUS ATTOR N EY Patented Aug. 30, 1960 FLAPPER VALVE Robert B. Watrous, Philadelphia, Pa., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Filed Dec. 3, 1954, Ser. No. 472,865

7 Claims. (Cl. 137-82) The primary object of the present invention is to provide a thin resilient flapper valve of novel type for use in control apparatus, and particularly control apparatus regulating the pressure of a compressible fluid in a pressure chamber by variably throttling a bleed orifice or outlet from said chamber. More specifically, the invention is characterized by the novel form of the flapper valve and the manner in which it is adjusted to regulate the throttling efiect impressed on the bleed orifice.

The flapper valve may be in the form of a plastic plate in some cases, but in its preferred practical form, the flapper valve is in the form of a metallic strip having opposing ends which are compressed by a variable compressive force, to thereby variably bow said entire strip so that the central portion of the strip is moved toward and away from the bleed orifice of the pressure chamber.

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 drawings and descriptive matter in which I have illustrated and described preferred embodiments of the invention.

Unless otherwise noted corresponding components shown in the various figures carry corresponding reference characters.

Of the drawings:

Fig. l is an elevation of one embodiment of the invention;

Fig. 2 is a section on the line 22 of Fig. 1; and

Fig. 3 is an elevation of a modified form of the invention.

In the simple form of the invention shown in Figs. 1 and 2, A represents the discharge nozzle of a pressure chamber, not shown, to which a compressible fluid is transmitted. The rate at which fluid is discharged by the nozzle A through its discharge port a is dependent on the fluid pressure in the nozzle A, and on the distance between the discharge end of the port a and the adjacent portion of a flapper valve B. As shown in Figs. 1 and 2, the valve B is in the form of an elongated thin flexible strip or plate of tempered steel or other spring metal. Said valve may well be and as shown is of a length appreciably greater than the width of the valve, and is transverse to the axis of the orifice a. Ordinarily each of the two ends of the valve B are at approximately the same distance from the orifice outlet.

In its normal operating condition shown in Figs. 1 and 2, the flapper valve B is flexed or bowed, so that the central portion of the valve is normally relatively closer to the discharge end of the nozzle A than is the plane bb including the end portions 1) and be: of the valve. With the arrangement shown in Fig. 1, the valve end portion b may well be directly above the valve end portion ha. The lower valve end ba is shown extending into and being received by a notch or recess c formed in the upper side of a stationary block or abutment C, while the upper end b of the valve B extends into a notch d formed in the under side of a normally horizontal beam D.

One end of the beam D is pivotally connected to a Stationary support E. As shown, the pivotal connection is of the well known type comprising thin flexible metal plates F and f at right angles to one another. As shown, the plate F is vertical and has a lower portion abutting against and attached to the adjacent end of the beam D, and has an upper portion alongside and attached to the vertical side of the stationary supporting element or abutment E. The plate f is horizontal and has one portion resting on and secured to the upper side of the beam D, and has-a second portion which extends beneath and is attached to the under side of the support E. A vertical thrust member G, laterally displaced from the member E, bears against the upper side of the beam D and subjects the latter to a variable load force which variably depresses the beam D, and variably bows the central portion of the flapper valve toward the nozzle A and away from a stationary stop H. The latter may well be and as shown is in alignment with the nozzle A and at the opposite side of the flapper B from said nozzle. The stop H is spaced closely enough to the nozzle A to insure that the down movement of the beam D will move the central portion of the flapper B toward, and not away from, the nozzle A.

The apparatus shown diagrammatically in Figs. 1 and 2, is characterized by its inherent capacity for an unusually high ratio of the horizontal movement of the central portion of the flapper valve toward and away from the nozzle A, relative to the vertical movement of the flapper valve end portion b toward and away from the abutment C. The flapper will thus possess a high gain characteristic, or, in other words, an unusually high ratio of movement of its central position with respect to its minute end portion movement. As will be apparent, the apparatus shown in Figs. 1 and 2 is adapted for a variety of uses. In particular, it is adapted to increase or decrease a fluid pressure in a nozzle in accordance with respective increasing or decreasing variations in the pressure impressed on the beam D by the thrust member G. The latter may be actuated in various ways and for various purposes. For example, the thrust member G may be attached to a flexible diaphragm forming one wall of a variable pressure chamber. it is noted that the present invention is well adapted as a substitute for flapper and beam elements now in commercial use in differential pressure measuring apparatus, and in transmitting apparatus which are respectively disclosed in the pending application for patent of Booth, Du Bois, and West, Serial No. 248,358, filed September 6, 1951, now Patent No. 2,808,725, and in the pneumatic temperature transmitting controller disclosed in the pending application of Konrad H. Stokes and Robert C. Whitehead, Ir., Serial No. 347,812, filed April 9, 1953, now Patent No. 2,823,688.

The apparatus collectively shown by way of example in Figs. 1 and 2 may be modified in various ways. One such modification is shown by way of example in Fig. 3, wherein a horizontal beam Da has one end supported by resilient elements F and f on a stationary support E in a manner similar to that shown for the parts F, f and E as shown in Fig. l. The beam D also contains a notch a." cut therein to retain the end b of the flapper B in a manner identical to the notch d of beam D which retains the end I: of the flapper B shown in Fig. 1. The lower end of the flapper c is shown mounted in a stationary block in an identical manner to that shown in Fig. 1. The second end of the beam Da is connected More specifically,

, to the horizontal diaphragm l of a diflerential pressure measuring device having pressure chambers J and K respectively above and below said diaphragm. The

chamber J is connected by a branch pipe Li toa source;

of fluid under. one pressure on one side of the orifice n and the chamber K' is connected by a branch pipe M 'to aportion of the conduit N on the other side of the orifice n through which the fluid flows ,at a difierent pressure than is present in the branch pipe L. As shown, the conduit N includes an orifice plate n with a central orifice at n, and extending across the bore of therconduit between the, conduit connections to the pipes L and M. Asfluid flows through the conduit N in the direction indicated'by the associated arrow, the pressure in the 'portion of the conduit N at the left of the orificepla'te tionP. parallel to the beam Da and rigidly connected to are located in *an elbow-shaped extension R of the cham the latter by an elbow element Q. The parts O and P ber K. The end of the chamber extension R nearest to the beam section Da is sealed by an elongated bellows S which loosely surrounds the right hand end portion of the beam section P and whose left end is welded or otherwise attached to the beam section P. The other endof the bellows S has a radial disc-like extension s which is welded or otherwise attached to the end of the wall surrounding the horizontal portion of the beam section P adjacent the beam Da. As will be ap'parent,;the nozzle A, the flapper B and the beam Da of Fig. 3, cooperate as do'the elements A, B, and D of Fig. 1.

While, in accordance with the provisions of the statutes, I have illustrated and described the best forms of embodimentof my invention now known'to me, it will be apparent to'those skilled in the artithat changes may be made in 'the fonns of the apparatus disclosed without departing from the spirit of myinvention as set forthin the appended claims and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

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

direction to shorten the 'distance between said end portions.

4. A motion amplifying motion to pressure transducer, comprising a single thin elongated flapper plate in a partially bowed position, said'flapper plate being supported at one end and operably positioned in cooperative relation with respect to a pneumatic nozzle to regulate the back pressure to .be transmitted from said nozzle, and a motion input means connected to act directly on the other end of said flapper to impart to the entire flapper a boxing motion proportional to the input motion.

5. Apparatus as specified inclaim 1 wherein the said motion of. said central portionmoving toward said nozzle will be of a magnitude greater than the motion of the ends of the plate 'overja predetermined range whereby a motion amplification is achieved.

6. A 'motion' amplifying flapper valve structure, coinprising a single elongated resilient thin flat plate flapper, a compressive/force of varying magnitude acting directly on one of two opposite elongated ends of said flapper while thesecond end is pivoted on stationary block to flexthecenter portion of said flapper into a bowed positiontoward a pneumatic bleed nozzle whensaid force is decreased, said bowing action of said flapper being of such a character that the amount of a fluid bled from said nozzle will be decreased in an ever'increasin'g proportional manner as said center of said flapper is flexed toward said nozzle and be increased in an ever decreasing proportional manner as said center portion is flexed away from said nozzle to thereby alter the-magnitude of said fluid retained within said nozzle.

7. A motion amplifying apparatus for producing a fluid pressure variable in accordance with the magnitude of an input force, comprising a nozzle member having a pressure chamber therein, a supply fluid passing into 7 said chamber and out of said member, a single elongated resilient flapper of a thin flat'metalic plate configuration operably positioned toregulate the flow of; fluid issuing from said'nozzle and a flapper support means for applying said'input force to flex the entire length of said flapper into a bowed position toward said nozzle and into said 1. A motion amplifying flapper valve structure opera- 7 tive to variably throttle a fluid flowing from the bleed nozzle of a pressure chamber to alter the magnitude of the pressure ofsaid fluid within said chamber, comprisand move its'central portion transversely to'a' plane .ineluding said end portions.

2. Apparatus as specified in claim 1','.in'cluding a stop element in position to compel said body to bow in one direction only.

.3. Apparatus 'asspecified in claim 1, including a beam, a stationary support, and a pivot aboutjwhich' said beam 1 may turn'in the direction to press the other end portion toward said support, and means for applying a variable a force to said beam to turn the latter about said pivot in the flowfluid issuing therefrom to increase'the pressure of said supply fluid in said pressure chamber as the magnitude'of said input force is increased and to cause said flapper to move from'its bowed position to a gradually diminishing bowed position away from said nozzle to decrease the pressure of said supply fluid in said chamber .as' said magnitude of said input force is decreased.

References Cited in the file of this patent UNITED STATES PATENTS.

Kay July 19, 1932 2,140,947 Andersson Dec. 20, 1938 2,268,783 .Tate' Jan. 6, 1 942 2,454,946 Rosenberger Nov. .30, 1948 2,638,911 Griswold May .19, 1953 2,667,886 'Brewster' Feb. 2, 1954 2,672,151 Newbold Mar. 16, 1954 2,688,334 Jewett Sept. 7,1 1954 2,717,516 Swift Sept. 13, 1955 2,718,878 Du Bois Sept. 27, 1955 FOREIGN PATENTS 216,538 Great Britain July 30,1925 276,755 1951 Switzerland Oct, 16,

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