GB2072802A - Rotary control valve - Google Patents

Abstract

A rotary control valve (9) has a casing (10) defining a receptacle (11) therein. The casing has a main axis (11a) and spaced flow ports (40-40) which communicate with the receptacle. A flow-control member (13) is rotatably disposed within the receptacle. The member (13) has a through-bore (14a), whereby, in use, the opposite open ends of the bore are in register with the flow ports (40-40) when the control member (13) is in its fully-open position. A pair of elongated orifice slots (44) extend circumferentially of the member (13) in opposite directions, generally from the opposite open ends of the bore (14a). Each of the slots (44) is defined by converging walls (45). The member (13) has non-slotted closure portions between the trailing ends (46) of the orifice slots (44) and the adjacent ends of bore (14a). The closure portions (47) are adapted to close off the flow ports (40-40) in the flowway-closing positions of the control member (13). The improvement resides in that the member (13) has a silencing chamber surrounding the wall of bore (14a) and communicating with the slots (44), and silencing means (44a) are disposed in the silencing chamber. <IMAGE>

Description

SPECIFICATION Rotary control valves with silencing means This invention relates to rotary control valves which include noise-silencing means.

In U.S. Patents 3,443,793; 3,558,100; and 3,612,102 are described several valves with rotary-control elements which have unique advantages over conventional rotary-control valves. However, these patented valves have no noise-silencing means.

Control valves with noise-siliencing means are known from the patent and technical literature.

For example, valves with noise-silencing means are described in the following U.S.A.

patents: 3,665,965 3,693,659 3,704,726 3,722,854 3,773,085 3,776,278 3,813,079 3,880,399 3,941,350 3,978,891 3,990,475 However, the known valves have a common characteristic in that the silencing means are continuously interfere with the fluid flow through the valves, even when the valves are in their fullyopened position. As a result, the silencing means continuously interefere with the fluid flow through the valves.

According to the present invention, there is provided a rotary control valve which has a casing that defines a receptacle. The casing has a main axis and spaced flow ports which communicate with the receptacle through a fluid flowway. A flow-control member is rotatably disposed within the receptacle. The member defines an axial bore, whereby, in use, the opposite open ends of the bore are in register with the flow ports of the casing when the control member is in its fullyopen position; and the wall of the control member has a pair of elongated orifice slots extending circumferentially in opposite directions, generally from the opposite open ends of the member's bore. Each of the slots is defined by converging walls. The control member also has non-slotted closure portions between the trailing ends of the orifice slots and the adjacent ends of the bores.

The closure portions are adapted to close off the flow ports in the flowway-closing position of the control member.

The improvement of this invention resides in that said control member has a silencing chamber which surrounds the wall of the bore, and silencing means disposed inside this chamber.

The silencing means produce a silencing effect on fluid flowing through the valve's flowway. This effect if produced only when the flowway is throttled by the orifice slots.

In one embodiment, the silencing means include a multiplicity of balls.

Preferably the valve has a spool consisting of an inner tube and an outer tube which forms therebetween the silencing chamber. The wall of the outer tube has a plurality of slots.

The wall of the inner tube is preferably unperforated, and the tubes of the spool are eccentrically mounted.

The balls fill the silencing chamber and the orifice slots.

In another embodiment, the silencing means include a plurality of angularly-spaced, radially and longitudinally extending ribs which are staggered to establish a convoluted, multi-path fluid flow pattern between the ribs.

Preferably, the plurality of perforations are, in use, in fluid communication between said bore and said silencing chamber.

In all embodiments of the invention, the fluid flow through said flowway is unhindered when the flowway is not throttled by the orifice slots.

Ways of carrying out the invention are described with reference to the drawings which illustrate specific embodiments, in which: Figure 1 is a vertical, sectional view of a rotary control valve which has a flow-control, spherical element that incorporates the noise-attenuating means in accordance with one embodiment of this invention; the sphere has an axial, cylindrical bore, which is shown in the valve's fully-opened position, and a pair of spiral converging, throttling orifice slots.

Figure 2 is a view in perspective of the spherical control element shown in Figure 1.

Figure 3 is a view similar to Figure 1 but showing the spherical control element in its throttling, partly-open position; and the throttling slots of the control element face their corresponding inlet and outlet ports of the valve.

Figure 4 is an end view of the valve shown in Figure 1, with the control element in a position just starting to close.

Figure 5 is a plan view showing the open end of the bore in the control element and a slot associated therewith and extending therefrom.

Figure 6 is an enlarged sectional detail view which shows a portion of (1) the perforations in the wall of the axial bore in the control element, (2) the silencing chamber surrounding the wall of the axial bore, and (3) the associated throttling orifice slot. The chamber and the slot are filled with spherical balls which are retained therein by transverse pins.

Figure 7 is a view on line 7-7 of Figure 6.

Figure 8 shows an alternate shape for the balls which are used to fill the chamber and the orifice slots in the embodiments shown in Figure 6.

Figure 9 is a vertical, partly sectional, view of the valve which shows the spherical control element in its fully-closed position.

Figure 10 is a vertical, sectional view of another embodiment of the spherical control element which is provided with noise-attenuating ribs instead of balls; the valve is shown in its fully-open position and the wall of the axial bore is perforated to allow the bore to communicate with the surrounding silencing chamber.

Figure 11 is a view similar to Figure 10 but with the spherical element in a position just starting to close. The ribs are shown in perspective.

Figure 12 show a modification of the valve shown in Figure 10 with the spherical element in its partly-open position. The wall of the element's axial bore has no perforations therethrough.

Figure 13 is a view on line 13-13 of Figure 12.

Figures 14-1 6 illustrate a method of manufacturing the spherical element for use with the silencing means. Figure 14 is a view of the spherical element prior to receiving a silencing spool. Figure 15 shows an embodiment of such a perforated silencing spool, and Figure 16 is a view which shows the silencing spool forcibly inserted into the bore of the spherical control element.

Figure 17 is a vertical, sectional view of another embodiment of the valve, shown in its fully-closed position, wherein the silencing spool defines a chamber filled with balls, and the chamber is formed between a pair of non-concentric tubular sleeves.

Figure 1 8 is a perspective view of the spherical control element taken on line 18-18 of Figure 17; and Figure 19 is another view of the control element taken on line 19-19 of Figure 17.

To facilitate the description of the drawings, the same numerals will be used throughout the drawings to designate the same parts. Similar parts are sometimes designated with the same numerals followed by a prime (').

In Figures 1-9, the low-noise, rotary control valve is generally designated as 9. It includes a hollow casing 10 constructed of two semispherical parts 1 Oa and lOb which carry annular mating flanges 1 Oc and 1 Od, respectively. The flanges are interconnected by bolts 1 Oe. Casing 10 defines a generally-spherical, internal receptacle 11 which communicates with coaxially-registering circular inlet and outlet flow ports 40-40 on diametrically-opposite sides of casing 10. Ports 40 40 define therebetween a flowway 40a having a longitudinal axis 40b.

A fluid flow control element, generally designated as 13, comprises a sphere 14 having an axial bore 14a forming a constant-area orifice therethrough. Bore 1 4a has a longitudinal center axis 1 4e (Figure 2). The bore's wall 1 4b has a multiplicity of angularlv-spaced, radially-extending perforations 14c. A" outer cylindrical chamber 1 4d completely surrounds wall 1 4b and fluidly communicates with bore 14a through the radial perforations 14c.

The cross-sectional area of the control element's bore 1 4a is substantially equal to the cross-sectional area of each one of flow ports 40-40. Sphere 14 is rotatably mounted inside receptacle 11 to vary the valve's effective orifice area. When sphere 14 is rotated to its fully-open position (Figure 1), the open opposite ends of bore 1 4a become in registration with the circular flow ports 40-40, and the longitudinal axis 1 4e (Figure 2) of bore 1 4a will become coincident with the axis 40b of the flowway 40a through the valve's casing 10.

A pair of generally-triangular orifice slots 44 (Figure 2) in the body of sphere 14 extend generally-circumferentially and in opposite directions from the opposite open ends of bore 14a. Each orifice slot 44 is formed by a pair of walls 45 which are inclined inwardly at an acute angle to the axis 1 4e of bore 1 4a and converge to form a trailing end 46 (Figure 5). The remaining non-slotted areas of sphere 14 lying in back of and around trailing ends 46 define closure portions 47 (Figure 9) which seal, in the flowway-closing position of sphere 14, against a pair of conventional seals 47a inside flow parts 40 40.

Sphere 14 is provided with a pair of oppositelyextending, coaxial, cylindrical trunnions 22-22 (Figure 3), either one of which may be the rotating stem. Trunnions 22-22 are suitably mounted in coaxial openings 16-1 6, at diametricallyopposite points on sphere 14, and project outwardly from sphere 14 through coaxial tubular bosses 12-12 at diametrically-opposite points on casing 10.

The coincident axes of trunnions 22 and bosses 12 define an axis of rotation 16a for sphere 14.

Axis 1 6a is coincident with the main axis 11 a of the receptacle 11. Main axis 11 a is disposed at an acute angle to the longitudinal axis 1 4e (Figure 2) of bore 14a. This acute angle also corresponds to the angle between the flowway axis 40b (Figure 1) and the main axis 11 a of receptacle 11.

In a plan development (Figure 5), each slot 44 has an elongated, generally-triangular configuration. In general, the angular lengths of both orifice slots 44 are equal and can be less or greater than 900. These angular lengths have a range preferably from about 1800 to about 2700.

Such an extended angular length for each slot 44 will permit rotation of sphere 14 through an angle of up to about 2700 or more, between its fullyclosed and fully-opened positions. This provides an extended range for varying the valve's effective orifice area through the sphere 14. It is, therefore, possible to grandually and accurately throttle the flow of fluid through the flowway 40a of valve 9.

In the embodiment of the valve, shown in Figures 1-9, the sphere's cylindrical chamber 1 4d and each orifice slot 44 is filled with silencing means. In one embodiment such silencing means are suitably-dimensioned balls 44a (Figure 6) which are retained in chamber 1 4d by transverse pins 44e, as shown.

When valve 9 is fully opened, as shown in Figure 1, bore 1 4a will allow the total fluid from flowway 40a to flow through. The fluid will fill and pressurize chamber 1 4d (Figure 1) and slots 44 through the perforations 14c. Since bore 1 4a has the same cross-sectional area as each of ports 40-40, the fluid flow through bore 14a will encounter a negligible pressure drop and, therefore, no appreciable noise will be generated by the fluid flowing through the valve 9.

Thus, in its non-throttling, fully-open position, valve 9 causes practically no pressure drop in the fluid flowing therethrough, which is a very important advantage of the present invention.

In the fully-closed position of the valve (Figure 9), the sphere's closure portions 47 will cover the flow ports 40-40 and no flow of fluid will take - place through the body of sphere 14.

At any other partially-open position of valve 11, between its fully-opened and fully-closed positions, at least a part of the fluid will flow through the portions of the orifice slots 44 which are exposed to ports 40-40 (Figure 3). In some positions of the sphere, as shown in Figure 4, the fluid will flow partly through bore 1 4a and partly through the exposed portions of orifice slots 44.

Moreover, in any partially-open position of the valve, the silencing balls 44a (Figure 3) in chamber 1 4d and in the orifice slots 44 will cause the fluid flowing therethrough to have a convoluted multi-path instead of a straight path.

Thus, the fluid will flow from inlet port 40 into a related orifice slot 44 and from there into chamber 14d. A portion of the fluid will flow through perforations 1 4c while the remainder fluid portion will flow through chamber 14d. Both fluid portions will recombine and exit through the diametrically opposite slots 44 facing the diametrically opposite outlet ports 40. The fluid's paths are schematically represented by the arrows.

Accordingly, balls 44a and perforations 1 4c create a high pressure drop in the sphere's throttling positions, thereby appreciably reducing the noise which would otherwise be generated by the valve when its sphere 14 is rotated to its throttling, partially-open positions. The balls 44a can be spherical (Figure 1). Non-spherical balls 44'a (Figure 8) can be employed also.

In the embodiment of the control valve 9a, shown in Figures 10 and 11, which is similar in most respect to the valve embodiment shown in Figure 1, the volume of chamber 1 4d is divided by a plurality of angular-spaced, radially-and longitudinally extending ribs 60, each having one or more openings 61 therein. Openings 61 are staggered to establish a non-circuitous, convoluted fluid flow pattern between ribs 60, as represented by the arrows 63.

Although not shown shown in Figures 10 and 11 , the orifice slots 44 can also be filled with balls 44a to obtain an additional silencing effect. In all other major respects, the valve embodiment, shown in Figures la and 11, is similar to the embodiment shown in Figure 1.

In the embodiment of the control valve 9b, shown in Figures 12-13, the wall 1 4b of bore 1 4a is solid and contains no perforations, otherwise the structure is similar to that of the valve embodiment, shown in Figures 10 and 11. It will be noted in the valve embodiment 9b of Figures 12-13, that when orifice slots 44 are opposite to ports 40-40, fluid can flow from one orifice slot 44 to the diametrically-opposite orifice slot 44 only between openings 61 in the ribs 60 and through chamber 14d, as illustrated by the arrows 64 and 65.

Thus, in the valve embodiments 9a and 9b wherein the body of sphere 14 is provided with ribs 60, by proper juxtaposition of the ribs' openings 61, a non-circuitous fluid flow pattern can be established. The flow will be from the first chamber 60a, defined between an adjacent pair of ribs, to a second such chamber 60b, and from the second such chamber to another such chamber, etc. The fluid will flow circumferentially across the stack of ribs 60 in non-circuitous and in axial convoluted paths.

Figures 14-1 6 show a preferred method of constructing control element 13. In sphere 14 is drilled an axial bore 70 whose longitudinal axis is coincident with a diameter of sphere 14. A hollow tube 75, having a pair of annular end flanges 74 74, forms a spool 72. The wall of tube 75 forms a bore 73 and has a multiplicity of perforations 14c. The outer diameter of flanges 74 is slightly larger than the inner diameter of bore 70 to provide a tight fit when spool 72 is forcibly inserted into bore 70. Thereafter, the outer faces of flanges 74 are shaped to the configuration of sphere 14 so that the flanges will not interfere with the sphere's rotation inside the receptacle 11 (Figure 1).

The outer cylindrical wall of tube 75 and the cylindrical wall of bore 70 form therebetween the desired chamber 1 4d within which can be installed the silencing means (balls 44a or ribs 60), as previously described. For the valve embodiments 9a and 9b, shown in Figures 10-11 and 12-13, respectively, the ribs 60 can be cast on or welded to the outer cylindrical wall of tube 75.

The silencing means, such as tLhe ribs 60 on the spool 72 or the balls 44a, cause the fluid to flow in chamber 1 4d in a plurality of paths having a convoluted fluid flow pattern. Fluid can also flow between bore 1 4a and chamber 1 4d through the perforations 1 4c. As a result, the fluid flow becomes broken up into discrete jets. The silencing means and the perforations 1 4c create noise-attenuating effects on the fluid as its flows and is being throttled through the control member 13 of the valve.

In the embodiment of the control valve 9c, shown in Figures 17-19, a hollow spool 72' is formed, using a pair of eccentric, spaced-apart tubes 81, 82 which form therebetween a chamber 83. The width dimension of chamber 83 gradually increases from a minimum to a maximum depending on the eccentricity between tubes81 and 82.

Spool 72' has an axial bore 1 4a. The wall of the outer tube 82 has a plurality of suitably arranged slots 84 (Figure 19) extending therethrough. Slots 84 are preferably elongated, narrow, iongitudinally-extending and angularly staggered.

The inner tube 81 could be perforated but in the valve embodiment 9c it is solid. Tubes 81,82 are held together in eccentric, spaced relation by end flanges 74a which have inwardly and axially extending shoulders 74b, 74c of different thicknesses. Flanges 74a have axial holes 74d therein.

The construction of sphere 14 is similar to that described in connection with Figures 14 16.

First is drilled an axial bore 70 whose axis is coincident with a diameter of sphere 14. The outer diameter of flanges 74a is made slightly larger than the inner diameter of bore 70 to provide a tight fit when spool 72' is forcibly inserted into bore 70. Thereafter, the outer faces of flanges 74a are shaped to the configuration of sphere 14 so that these flanges will not interfere with the sphere's rotation inside the receptacle 11 (Figure 1). The open space, between the outer tube 82 of spool 72' and the cylindrical wall of bore 70, defines a chamber 14d' whose function was previously described.

Chamber 83 is filled with variable-diameter balls 44a' which are retained therein by the opposite cylindrical walls of tubes 81-82 (Figure 17).

In the embodiment of the rotary control valve 9c, when the control element 13 is in its partiallyopen position, so that no portion of bore 1 4a is opposite to the inlet and outlet ports 40 40, and only the orifice slots 44 are opposite to the ports 40-40, the fluid will flow from the inlet port 40 into the opposite orifice slot 44 and then into chamber 14d'. From chamber 14d' the fluid will flow into chamber 83 through the slots 84. The balls 44a' will cause the fluid flowing through chamber 83 to have a convoluted, multi-path pattern instead of a straight path. A portion of the fluid will flow out from chamber 83 through the diametrically-opposite slot 44. From this slot 44 the fluid will flow into the diametrically-opposite outlet port 40. A portion of the fluid from chamber 83 will flow out also through the small holes 74d.

In the fully-closed position, as shown in Figure 17, the sphere 14 can be sealed off from inlet and outlet ports 40 40 by conventional seals 409.

Accordingly, balls 44a' and holes 74d appreciably reduce the noise which would otherwise be generated by the valve when its sphere 14 is rotated to its throttling, partially-open positions. When the two tubes 81,82 of spool 72' are eccentrically mounted, as shown in Figure 17, the noise reduction provided by the valve is greater than if the tubes were concentrically mounted (not shown).

Again, as in the previous embodiments of the rotary valve, the silencing means do not interfere with the free flow of fluid through the control element 13 when it is in its fully-open position.

Claims (11)

1. A rotary control valve having a casing defining a receptacle therein, said casing having a main axis and spaced flow ports which communicate with the receptacle through fluid flowway; a flow-control member rotatably disposed within said receptacle, said member having a body which is shaped to fit said receptacle and which defines an axial bore opening through the outer wall of said body, whereby, in use, the opposite open ends of the bore are in register with said flow ports when the control member is in its fully-open position; the wall of said body having a pair of elongated orifice slots extending circumferentially of the body in opposite directions, generally from the opposite open ends of the wall of said bore, each of said slots being defined by converging walls; said body having non-slotted closure portions between the trailing ends of said orifice slots and the adjacent ends of said bore, said closure portions being adapted to close off said flow ports in the flowway-closing position of said control member said body having a silencing chamber surrounding the wall of said bore, and silencing means being disposed in the silencing chamber.

2. The valve of Claim 1 characterized in that said silencing means produce a silencing effect on fluid flowing through said flowway when the flowway is throttled by said orifice slots.

3. The valve of Claims 1 or 2 characterized in that said silencing means include a multiplicity of balls.

4. The valve of Claim 1 characterized in that said flow-control member has a spool having an inner tube and an outer tube, said tubes forming therebetween said silencing chamber, and the wall of said outer tube having a plurality of slots.

5. The valve of Claim 4 characterized in that said tubes are eccentrically mounted and said silencing means are balls having different diameters.

6. The valve of Claim 5 characterized in that said balls fill said silencing chamber and said orifice slots.

7. The valve of Claim 1 characterized in that said silencing means include a plurality of angularly-spaced, radially and longitudinally extending ribs.

8. The valve of Claim 7 characterized in that said ribs having openings therein which are staggered to establish a convoluted, multi-path fluid flow pattern through the ribs.

9. The valve of Claim 1 through 8 characterized in that said silencing chamber has a plurality of perforations which are, in use, in fluid communication between said bore and said silencing chamber

10. The valve of Claims 1 through 9 characterized in that the fluid flow through said flowway is unhindered when the flowway is in its fully-open position.

11. A valve substantially as hereinbefore described with reference to and illustrated in the accompanying drawings.