US3633871A

US3633871A - Baffle for fluid valve

Info

Publication number: US3633871A
Authority: US
Inventors: Lothar Kirstein
Original assignee: Jos Schneider Optische Werke GmbH
Current assignee: Jos Schneider Optische Werke GmbH
Priority date: 1969-10-21
Filing date: 1970-08-07
Publication date: 1972-01-11
Anticipated expiration: 1989-01-11
Also published as: US3630230A

Abstract

An annular baffle, designed to act as a barrier interposed between two oppositely facing lands of a pair of piston heads in a fluid valve for controlling the axial thrust due to dynamic pressures reacting upon the piston, consists of one or more elastic arcuate members defining at least one radial gap which allows them to be fitted about a reduced piston portion intermediate the two heads upon introduction through one or more radial apertures in the valve housing; the resilient deformability of the baffle member or members is sufficient to enable such lateral introduction in a folded position.

Description

S taes tat Inventor Lothar Kirstein Bad Kreuznach, Germany Appl. No. 62,011 Filed Aug. 7, 1970 Patented Jan. 11, 1972 Assignee Jos. Schneider & Co. Optische Werke Bad Kreuznach, Germany Priority Oct. 21, 1969 Germany BAFFLE FOR FLUID VALVE 10 Claims, 15 Drawing Figs.

U.S. Cl 251/282 Int. Cl F161: 39/04 Field of Search 137/625 .4,

[56] References Cited UNITED STATES PATENTS 2,566,051 8/1951 Avery 251/282 X Primary Examiner-J-lenry T. Klinksiek Attorney-Karl F. Ross ABSTRACT: An annular baffle, designed to act as a barrier interposed between two oppositely facing lands of a pair of piston heads in a fluid valve for controlling the axial thrust due to dynamic pressures reacting upon the piston, consists of one or more elastic arcuate members defining at least one radial gap which allows them to be fitted about a reduced piston portion intermediate the two heads upon introduction through one or more radial apertures in the valve housing; the resilient deformability of the baffle member or members is sufficient to enable such lateral introduction in a folded position.

PATENTED JAN] 1 1972 3633.871

SHEET 1 [1F 3 F5 la FIG.|C

l7 2 I? l6 l5 5 fm INVENTOR LOTHAR KIRSTEIN Karl Tim ATTORNEY PATENTED mu 1 m2 SHEET 3 OF 3 F I G 3 b F E G 30 INVENTOR LOTHAR KIRSTEIN ATTORNEY BAFIFLE FOIR FLUID VALVE My present invention relates to a baffle for a fluid valve of the general type disclosed in commonly owned application Ser. No. 758,325, filed Sept. 9, 1968, now Pat. No. 3,543,648.

The system disclosed in that application and patent, as well as in a further application Ser. No. 55,783, filed July 17, I970, as a continuation-in-part thereof, includes a valve piston for the control of a fluid flow from two axially spaced inlet ports to respective outlet ports, or to a common outlet port, the two piston heads serving for the alternate cutoff of the two fluid streams upon an axial shifting of the piston. With piston heads of like diameter interconnected by a reduced stem portion defining an annular channel within the bore of a cylindrical valve housing, the static fluid pressures developed in such a channel exactly balance each other whereas the axial component of the dynamic pressure of the .flow has an unsymmetrical effect tending to shift the piston in the direction of the flow. Such a shift, occurring upon the incipient unblocking of an inlet port by the associated piston head, promptly tends to reblock that inlet so that an unstable, oscillatory condition may arise.

In order to prevent the existence of such an unstable condition and, in fact, to reverse the axial thrust of the controlled fluid to accelerate the response of the piston to a controlling pressure differential, the system disclosed in the aforementioned applications and patent may include deflecting means received in the annular channel between the piston heads, the deflecting means having the form of a stationary baffle occupying nearly the entire cross section of that channel at a location beyond the axial flow path of a fluid admitted through an inlet port unblocked by one piston head, thereby shielding the other piston head from the impact of the other fluid stream. The maintenance of a narrow annular clearance around the stem portion of the piston, preferably together with one or more small radial gaps in the baffle structure, helps preserve the static equilibrium.

My present invention has for its object the provision of an annular baffle for the purpose described which, whether constructed as a single ring member or as a combination of mutually complementary ring segments, can be installed in the cylinder bore, without disassembly of the valve, by introduction from without through a radial aperture or a plurality of such apertures constituting an inlet port thereof.

This object is realized, pursuant to the present invention, by constructing the baffle from elastic sheet material (e.g., metal or plastic) of sufficient resiliency to enable introduction into the cylinder bore in a folded position with spontaneous return to an annular shape after passage through the relatively constricted wall aperture or apertures. In its normal flattened state, the baffle has at least one radial gap enabling it to straddle the piston stem upon introduction into the cylinder bore, apart from facilitating the aforedescribed equalization of static pressures.

If the baffle consists of a single ring member extending over nearly 360, its insertion into the bore may be followed by a seating in an inner peripheral groove of the cylinder wall into which the ring reexpands upon axial alignment therewith. To facilitate extraction of that ring from that groove, its confronting ends separated from the radial gap may be provided with respective holes engageable by a suitable tool (such as a pair of pliers or tongs) serving to draw these ends together so as to reduce the outer diameter ofthe ring.

On the other hand, the baffle may also be subdivided into two or more ring segments each introduced into the cylinder bore through a respective radial aperture, this construction being particularly advantageous where the baffle is to be located in the region of the port defined by these apertures since in that case each ring segment may be formed with an integral extension remaining wedged in the aperture upon reexpansion.

The above and other features of my invention will be described in detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is an axial sectional view of a valve equipped with a unitary baffle member according to my invention;

FIG. la is a face view of the baffle of FIG. 1;

FIG. 1b is an edge view of the baffle of FIG. la in a folded position;

FIGS. 10 and Id are views similar to FIGS. 1, la and 1b, respectively, showing a slightly modified baffle member;

FIG. 2 is a similar view to FIG. 1, illustrating a valve with a composite baffle according to the invention;

FIG. 2a is a cross-sectional view taken on the line IIA-IIA of FIG. 2;

FIG. 2b is a face view of a segment of the baffle shown in FIGS. 2 and 2a;

FIG. 20 is an edge view of the same segment in a folded position;

FIGS. 2d and 2e are views similar to FIGS. 2b and 20, respectively, showing a slightly modified baffle segment;

FIG. 3 is a further view similar to FIG. 1, illustrating a valve with another composite baffle according to the invention;

FIG. 3a is a cross-sectional view similar to FIG. 2a but taken on the line IIIAIIIA of FIG. 3;

FIG. 3b is a face view similar to FIGS. 2b and 2d, showing a segment of the composite baffle of FIGS. 3 and 3a; and

FIG. 3c is an edge view similar to FIGS. 20 and 2e, showing the baffle segment of FIG. 3b in a folded position.

In FIG. 1 I have illustrated a cylindrical valve housing 2 accommodating a piston 3 with a pair of axially spaced

heads

4a and 4b separated by a stem 3a of reduced diameter. Valve cylinder 2 has a bore defining an annular channel about stem portion 3a, this channel communicating with an inlet port constituted by a pair of diametrically opposite apertures 6 and an outlet port constituted by a pair of diametrically opposite apertures 7. Piston head 4a has an edge 5 which is spaced from a confronting edge 11 of head 412 by an axial distance greater than the separation of

ports

6 and 7 whereby the two ports communicate with each other via a section 8 of the cylinder bore in the illustrated piston position but can be isolated from each other upon a rightward shift of the piston. The

valve assembly

2, 3 is surrounded, with interposition of packing rings 40, by a shell 36 (omitted in some succeeding Figures) from which it may be extracted to expose the

apertures

6 and 7; it will be understood that the shell has fluid lines terminating at points registering with these apertures for the circulation of a controlled liquid or gas.

When the piston is shifted from its blocking position to a position of incipient fluid flow as illustrated in FIG. 1, in response to a pressure differential developed across its

heads

4a and 4b, the inrushing fluid passing from port 6 to port 7 generates an axial thrust in the direction of head 4b tending to shift the piston toward the right with resulting reclosure of inlet port 6. Such undesired shifting is prevented by the interposition of a stationary baffle 14 between the two heads, just to the right of outlet port 7, which intercepts the axial flow and redirects the thrust radially outwardly through the apertures of port 7. The shielding of piston head 412 by the baffle 14 gives rise under these circumstances to a leftward component of the dynamic fluid pressure which accelerates the unblocking movement of the piston.

The inner periphery of housing 2 is formed with an annular groove 19 to receive the baffle 14 which, as best seen in FIG. la, is a nearly complete ring of sheet metal formed with a narrow radial gap 15.

FIG. 1 shows that the ring member 14, when seated in groove 19, leaves a narrow annular clearance 12 around piston stem 3a, the depth of this clearance being just sufficient to allow the ring to be extracted from the groove upon drawing of its two ends toward each other with the aid of a pron ged

tool engaging holes

16 and 17 in these ends. Such a pronged tool can be laterally introduced through the aperture 7 nearest the gap 15 for facilitating the extraction of the bafile member from the cylinder bore.

Baffle member 14 is resiliently deformable so as to be foldable into the position of FIG. lb in which it can be inserted or withdrawn through one of the apertures 7 and from which it may reexpand to straddle the piston stem 3a upon its introduction into the cylinder bore. Such resilient deformation is further facilitated if, as shown in FIGS. 1c and 1d, the baffle has the shape of a ring 114 identical with ring 14 except for the provision of several peripherally equispaced radial notches 18.

FIGS. 2 and show a generally similar housing 2 occupied by a piston 3' having

heads

4a and 4b, the cylinder being again provided with inlet and

outlet ports

6 and 7, respectively. In this instance, however, a composite baffle consists of four identical elements 20, each with a ring-segmental part 20a and a blade-shaped extension 20!; integral therewith. These elements are lodged in the four peripherally equispaced apertures defining the port 7; ring segments 20a again straddle with a small annular clearance 12 the stem portion 3a of the piston. The extension or wing portion 20b of each ring segment 20a has a curved outer edge 23 centered on the piston axis and engaged by the inner periphery of the surrounding shell 36. Each blade 20b also has a pair of laterally projecting shoulders 21 coming to rest on a flattened land of cylinder 2. The extremities22 of each ring segment 20a project slightly beyond the lateral edges of blade 20b and approach those of neighboring ring segments, leaving a small gap 13 therebetween. These lateral edges are received in generally radial grooves 24 formed in the walls of the apertures of port 7.

Each segmental baffle element 20, individually illustrated in FIG. 2b, can be folded about a median radius as shown in FIG. 20 to pass through the corresponding port aperture for emplacement in the cylinder 2 (with the lateral blade edges snapping into grooves 24) or for extraction therefrom. Naturally, the grooves 24 could also be located midway within the port apertures so that the same port 7 could serve as an outlet for two streams of controlled fluid respectively entering at port 6 and at a second inlet port, not shown, to the right of port 7' in FIG. 2, in the manner disclosed in the aboveidentified applications and patent.

As shown in FIGS. 2d and 2e, a slightly modified baffle element 120 may have its ring portion split by a slot 26 into two halves interconnected only by a narrow bridge piece adjacent outer edge 23 to increase the foldability of the segment about a median radius.

FIGS. 3 and 3a show a cylinder 2" and a piston 3", generally similar to those of the preceding embodiments, with

piston heads

4a, 4b" and ports 6", 7". This embodiment also comprises a composite baffle with four elements 27 each having a ring segment 35 attached by a narrow neck to a blade-shaped body. The connecting neck is defined by two lateral incisions 29, these incisions coming to rest within the apertures of port 7" upon emplacement of the baffle element. A peripheral annular groove 32, interrupted by the port apertures, receives the convex outer edges 31 of ring segments 35 while confronting edges on the generally T-shaped blade come to rest against shoulders 33 of the outer cylinder periphery. The lateral edges 28 of the blade simply bear upon the wall of the associated port aperture.

FIGS. 3b and 3c illustrate the baffle element 27 in its normal and its folded position, respectively. Emplacement and removal is similar to that of battle elements 20 in the preceding embodiment, except that the outer edges of element 27 do not contact the surrounding shell which has not been illustrated.

Naturally, the baffie of FIGS. 3 and 3a3c may also be usedlike that of the preceding embodiment-as a divider for an output port in which its segments are received.

I claim:

1. In a valve for the control of a fluid flow, comprising a cylinder with an apertured wall defining at least one inlet port and at least one outlet port opening at axially spaced locations into an axial bore and with a piston slidable in said bore, said piston having a pair of heads separated by a reduced portion of a length exceedin the axial distance of said inlet and outlet ports for alternately locking and unblocking a path from said inlet port to said outlet port upon an axial shifting of said piston, the combination therewith of annular baffle means of elastic sheet material defining a substantially continuous ring with at least one radial gap in said bore surrounding said reduced portion with small clearance, the resiliency of said sheet material being sufficient to enable introduction of said baffle means into said bore in a folded position by way of said apertured wall with spontaneous return to an annular shape in said bore.

2. The combination defined in claim 1 wherein said baffle means comprises an annular member extending over nearly 360.

3. The combination defined in claim 2 wherein said annular member is provided with at least one radial notch in its outer periphery.

4. The combination defined in claim 2 wherein said apertured wall is provided with an inner annular groove removably receiving said annular member.

5. The combination defined in claim 4 wherein said annular member has confronting ends provided with holes engageable by a tool for moving said ends toward each other to dislodge the member from said groove.

6. The combination defined in claim 1 wherein said baffle means comprises a plurality of mutually complementary ring segments, said one of said ports including a like plurality of peripherally spaced radial apertures in said wall, each of said ring segments having an integral extension wedged in a respective aperture.

7. The combination defined in claim 6 wherein said extensions are generally rectangular tabs narrower than said segments in peripheral direction.

8. The combination as defined in claim 7 wherein said tabs have outer shoulders bearing externally upon said wall.

9. The combination defined in claim 7 wherein each of said segments is centrally split by a generally radial slot extending into the respective tab but terminating short of an outer edge of the latter.

10. The combination defined in claim 9 wherein said slot broadens in a radially outward direction.

Claims

1. In a valve for the control of a fluid flow, comprising a cylinder with an apertured wall defining at least one inlet port and at least one outlet port opening at axially spaced locations into an axial bore and with a piston slidable in said bore, said piston having a pair of heads separated by a reduced portion of a length exceeding the axial distance of said inlet and outlet ports for alternately blocking and unblocking a path from said inlet port to said outlet port upon an axial shifting of said piston, the combination therewith of annular baffle means of elastic sheet material defining a substantially continuous ring with at least one radial gap in said bore surrounding said reduced portion with small clearance, the resiliency of said sheet material being sufficient to enable introduction of said baffle means into said bore in a folded position by way of said apertured wall with spontaneous return to an annular shape in said bore.

2. The combination defined in claim 1 wherein said baffle means comprises an annular member extending over nearly 360*.