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Publication numberUS3334656 A
Publication typeGrant
Publication dateAug 8, 1967
Filing dateOct 20, 1965
Priority dateOct 20, 1965
Publication numberUS 3334656 A, US 3334656A, US-A-3334656, US3334656 A, US3334656A
InventorsRobert F Boyle
Original AssigneePneumo Dynamics Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Rotary tape valve
US 3334656 A
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Description  (OCR text may contain errors)

1957 R. F. BOYLE 3,334,656

ROTARY TAPE VALVE Filed Oct. 20, 1965 2 Sheets-Sheet 1 INVENTOR.

ROBERT E BOYLE ATTORNEY Aug. 8, 1967 Filed 00%.. 20, 1965 R. F. BOYLE ROTARY TAPE VALVE 2 Sheets-Sheet 2 -3 11v VENTOR.

' ROBERT F. BOYLE AT TORNEY FIG. 8 "Q W United States Patent 3,334,656 ROTARY TAPE VALVE Robert F. Boyle, Parchment, Mich., assignor to Pneumo Dynamics Corporation, Cleveland, Ohio Filed Oct. 20, 1965, Ser. No. 498,654 9 Claims. (Cl. 137596) This invention relates to a fluid valve of the type in which control is accomplished by variably wrapping a flexible tape about a curved ported surface.

Rotary or rolling tape valves have been known as a broad class for a very long time and a wide variety of mechanical designs have been at least proposed in an effort to produce such a unit of commercially acceptable construction and performance. Since, in an elemental sense, the actuating principle requires a tape or flat strip to be wrapped and unwrapped on a curved surface in which the port to be controlled occurs, the performance of the valve is critically dependent upon the character of the interengagement of the tape and surface over a fairly significant area, and it has been found generally necessary to incorporate some design feature or means for maintaining tension in the tape and thereby adequate sealing force. A known valve assembly on this order, as an example, includes an adjustment screw attachment for one end of the tape so that actuation of the screw produces the desired tensioning of the tape, with the unit inward force applied by the tape as a result of the tension greater than any fluid unit force outward which might occur at the port. This expedient, and others which similarly involve a tightening or tensioning device for the tape, are not considered to be wholly satisfactory in view of the tendency for the adjusted condition to become changed in the normal circumstances of use of the valve over any significant period of time, with frequent attention and readjustment required to maintain the intended level of performance.

It. is an object of the present invention, accordingly, to provide such a rotary tape valve which is primarily distinguished and improved by the absence of any device for tensioning the tape or tapes as in the conventional designs, without loss of the positive sealing needed for proper control.

It is also an important object of the invention to provide a valve of the indicated class which is of greatly simplified construction, with resulting advantages and improvements in respect of both production and performance. The new valve design, more particularly, employs a simplified porting arrangement, minimizes critical dimensioning, and is relatively insensitive to contamination.

It is a further object of the invention to provide such a rotary tape valve having a substantially enlarged metering area, with all such advantages and improvements of the basic mechanical design being available in two, three, and four way valve assemblies.

A further object is the provision of a rotary tape valve assembly in which the porting is such to hold the operating noise to a very low level.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a longitudinal sectional view of a directional control valve made in accordance with the present improvements;

FIG. 2 is a transverse cross-section of the valve shown in FIG. 1 as viewed from the plane of the line 22 therein;

FIG. 3 is a further cross-sectional view the plane of which is indicated by the line 33 in FIG. 1;

FIG. 4 shows a simplified version of the valve, again in longitudinal section, in which the operation can be more readily explained and understood; and

FIGS. 5, 6, 7 and 8 are cross-sectional views of the valve construction of FIG. 4 respectively indicated by the correspondingly numbered lines therein.

Referring now to the drawings in detail, the fluid valve of FIG. 1 comprises a cylindrical housing 10 having an integral wall 11 at one end and being open at the other end. An end plate 12 closes the housing at such other end and is attached thereto by a plurality of screws, one of which is shown at -13. As shown, the end plate fits partially within the end of the housing and this interface is sealed by an elastomeric ring 14 carried in a peripheral groove in the inserted part of the plate.

The housing is formed with several ports in longitudinal spaced relation along the top, with these being designated respectively by reference numerals'and functionally as an inlet port 15, a first outlet port 16, a second outlet port 17, and an exhaust port 18. These housing ports are all tapped to receive line connections from fluid system components according to the indicated naming thereof. For example, the inlet port 15 would be thus connected to the source of the pressure fluid to be controlled, the first outlet port 16 would extend to one work performing or regulating device, the second outlet port 17 would be connected to another such device, and the exhaust port 18 provides for fluid return or discharge. With this characterization, it will be apparent that the illustrated embodiment is designed as a four way directional control valve.

The inner side wall of the housing extending immediately from the end wall 11 is, for a given axial length, of such reduced diameter relative to the remaining wall section as to provide an annular shoulder 19 normal to the axis and just beyond the first outlet port 16 in proceeding outwardly from the wall 11. A first transverse partition ring 20 is located in the housing 10 against this shoulder 19 and, continuing in the same direction, there is a first thin wall spacer sleeve 21 contacting the inner surface of the housing, a second partition ring 22 similar to the first, and a second spacer sleeve 23 engaged at its outer end with the housing-end plate 12. The length of the first spacer sleeve 21 is such that the distance from the first partition ring 20 to the axis of the inlet port 15 is the same as the distance from such axis to the second partition ring 22. The latter is located just inwardly of the second outlet port 17 at the spacing provided by the second sleeve 23 from the end plate 12 and approximately equal to that between the housing other end wall 11 and the first partition ring 20. Sleeve 21 is provided with an opening 24 in register with the inlet port 15 which it bridges, while sleeve 23 has an opening 25 in register with the second outlet port 17. The two partition rings 20 and 22 have peripheral grooves in which sealing rings 26 and 27 are disposed and provide peripheral sealing with the inner wall of the housing 10.

A cylinder 28 is supported within the valve for rotation on the axis thereof. At its outer end, this cylinder has a reduced end portion 29 supported within a ball bearing 30 carried in a recess in the inner surface of the housing end plate 12, and a stem 31 extends from this end of the cylinder outwardly through an opening provided for the purpose in the plate, through a seal ring 32, where- 3 by the stem is externally exposed so that it can beturned in any suitable manner to rotate the cylinder within the valve. The cylinder extends through the partition rings 20 and 22 in sealed relation, by virtue of the inner periphery sealing rings 33 and 34 of the same, and into a stepped recess in the housing end wall 11. This end of the cylinder is supported on a further ball bearing 35 positioned in the outer enlarged portion of the stepped recess, with the outer diameter of the cylinder being slightly reduced where thus engaged by the bearing, and the extreme end 36 is of still further reduced diameter and sealed to the housing wall by a sealing ring 37 in a surrounding groove,

the cylinder-receiving recess communicating with the exhaust port 18 as illustrated It will thus be apparent that the first and second partition rings, together with the cylinder, end wall, and end plate, form three separate sealed chambers within the valve designated by reference numerals 38, 39 and 40. It is intended that this valve be operative to provide communication through the cylinder 28 between the inlet port chamber 38 and either one of the chambers 39 and 40 respectively serving the first and second outlets 16 and 17.

For such purpose, the surface of the central portion of the cylinder 28 which is exposed in the chamber 38 is machined to provide chordal slots 41 and 42 to a predetermined depth and in the angular relationship shown in FIGS. 2 and 3. These slots are axially displaced and, with the cylinder in the rotative position illustrated in such figures, they extend to opposite sides from points closely adjacent the bottom center divergently upwardly to points which are spaced circumferentially a distance which is roughly one-fourth of the circumference of the cylinder. The slot 41 is bridged by a curved port assembly the outer surface of which is curved on the same radius as the cylinder and thus restores the original surface configuration. The port assembly shown comprises a body 43 of porous material, the character of which will be later described more in detail, and a perforated metal backing 44 at the inner surface, with the assembly having its edges received in a groove formed about the periphery of the slot 41 for the flush mounting in the cylinder 28. It is also preferred that the port assembly include a continuous elostomeric seal 45 about and projecting slightly above the exposed surface. The other centrally located cylinder slot 42 is provided with a similar port assembly body 46, backing 47, seal ring 48.

A first longitudinal passage 49 is provided in the cylind-er 28 extending from the inner end to and ending in a local recess 50 in the bottom of the slot 41. The other end of the passage is permanently closed by a plug 51, and that section of the cylinder which is within the valve chamber 39 has a lateral passage 52 from the surface to the first longitudinal passage 49 where the latter traverses this cylinder section. Itwill, accordingly, be apparent that fluid from the inlet chamber 38 can flow through the port 43 when open and passages 49 and 52 into the valve chamber 38 serving the first outlet 16. The location of the exposed end of the lateral passage 52 is such that this opening will not be obscured in any rotative position of adjustment of the cylinder 28, the control'of this flow being accomplished at the port 43 in a manner to be described.

A second longitudinal passage 53 is. provided in the cylinder 28 to extend in corresponding manner from the central slot 42 to a second lateral passage 54 which opens in the valve chamber 40. The two passages 49 and 53 are angularly displaced and non-intersecting, With the second lateral passage 54 always open in the chamber 40 which serves the second outlet 17 and fluid flow in this direction controlled at the port 46 within the inlet chamber 38.

A third longitudinal passage 55 is provided in the cylinder 28 to extend from the inner end, at which it is open and in communication with the exhaust port 18, continuously along the length of the cylinder to a closed end in that portion which is within the outermost valve chamber 40. The axial section of the cylinder exposed in the valve chamber 39 is provided with a porting assembly 56 which is the same as that formed by the slot 42 and port 46, and such additional port is, moreover, in the same angular relation. The port 56 is, however, in communication with the third longitudinal passage 55 and hence the exhaust port 18. A final port assembly 57 is provided in the cylinder section within the other end valve chamber 40, with this assembly being of the same construction and disposition as that defined by the slot 41 and port 43 of the central section but also in communication With the bottom passage 55 to the exhaust port. A transverse section at the center of the valve chamber 40 would thus be substantially identical to that of FIG. 2 and a comparable section of the valve chamber 39 similar to FIG. 3, with only the noted internal communications commonly with the exhaust or discharge passage 55 instead of the respective passages 49 and 53 at the inlet side.

With further reference particularly to FIGS. 2 and 3, the port 43 is shown as closed by a flexible metal tape length 58 permanently attached by a screw 59 to the cylinder 28 at the approximate top center and, in this view, extending counterclockwise to the bottom center and thereby fully obscuring the outer surface of such port, the tape width being greater than the width of such surface. This tape length is, more particularly, an end length of a negator spring 60 which is supported on a pair of ball bearings 61 supported in turn on a stationary bottom shaft 62 having its ends respectively received in openings in the partition rings 20 and 22. The axis of the shaft 62 is parallel to that of the cylinder, and the two ball bearings are held apart by an intervening spacer sleeve 63 on the shaft. The diameter of the negator spring 60 is noticeably smaller than that of the cylinder 28, the latter being approximately twice the former in the illustrated embodiment, and this spring is reversely wrapped or wound on the cylinder. There is, accordingly, realized an inherent spring force acting on the wrapped length of the tape 58 which urges the same inwardly or against the surface of the cylinder 28 and hence the port 43 with which it is associated, the seal ring or gasket 45 being engaged by the tape.

As shown in FIG. 3, an identical negator spring 64 is employed at the other inlet chamber port 46. This spring is also supported on ball bearings 65, with an intervening spacer sleeve 66, on the stationary bottom shaft 62 and, in this case, the spring tape 67 of course extends from the top center screw attachment 68 about the surface of the cylinder 28 and over the port 46 in a clockwise direction. Further negator springs 69 and 70 are provided within the valve chambers 39 and 40 respectively to cooperate with the ports 56 and 57 thereof, the relative arrangement of the further spring 69 in the chamber 39 being exactly the same as that of the spring 64 and, correspondingly, the spring 70 in the chamber 40 being disposed and operative similarly as the spring 60. The spring 69 is shown as mounted on a separate shaft 71 in the housingv end wall 11, while the remaining spring 70 is mounted on a comparable shaft 72 supported in the housing end plate 12, with both of these mountings including ball bearings, not shown, as previously described.

The operation of the valve can be more readily explained and understood in the structural form illustrated in FIGS. 4-8, with this assembly being more concerned with function than with a commercially suitable design as in the case of the first described embodiment.

The assembly shown in FIG. 4 thus comprises an elongated housing 73 of simpler rectangular cross-sectional shape, with a top center inlet opening 74 and first and second work outlets 75 and 76 respecitvely to either side in the longitudinal direction. The exhaust opening 77 is in one end wall of the housing, at the center, and cylinder 78 is mounted suitably for rotation within the housing between the end walls thereof, a stem 79 projecting through the other end of the housing for external actuationto rotate the cylinder. The stem opening is sealed by a ring 80, and additional sealing rings 81 and 82 respectively engage peripherally the extreme end portions of the cylinder 78.

There is a first transverse partition 83 in the housing between inlet 74 and the first outlet 75, with a circular central opening through which the cylinder 78 extends. A second similar partition 84 is provided between inlet 74 and the second outlet 76 and also traversed by the cylinder, the latter being sealed at the two partitions by sealing rings 85 and 86.

The inlet 74 thus leads to a sealed central chamber 87 and two further sealed chambers 88 and 89 are formed in respective end portions of the housing where the outlets 75 and 76 are located. The cylinder has an axial exhaust or return passage 90 extending from the end adjacent the exhaust opening 77 substantially to'the other end. Within the end chamber 88, the cylinder 78 is cut to form an approximately sector-shaped slot 91 communicatingwith the axial return passage 90, as shown most clearly in FIG. 5, and a curved port screen or body 92 of porous material is mounted over the slot 91 as a continuation of the surface of the cylinder. The port 92 is here shown as closed by a negator spring 93 rotatably supported on a fixed bottom shaft 94 and reversely Wrapped about approximately half of the cylinder surface to a screw attachment 95 at its free end. Port 92 is at the left side of the cylinder in this illustrated condition of the latter, and extends from a lower end adjacent the bottom center more than a third of the total circumference of the cylinder.

A passage 96 in the cylinder 78 extends from an opening in the exposed surface of the cylinder within the chamber 88, entirely clear of the spring tape 93, to a slot 97 in the cylinder surface within the central chamber 87. This slot 97, which is approximately of the same circumferential extent as the slot 91 but to the opposite side, is provided with a like port screen or body 98, and a second negator spring 99 rotatably supported on a further bottom stationary shaft 100 is wrapped reversely over such port and to a free end screw attachment 101 to the cylinder, the arrangement being most clearly illustrated in FIG. 6.

As shown in FIG. 7, the central section of the cylinder 78 within the inlet chamber 87 also has an axially displaced but corresponding port 102 and slot 103, with a third negator spring 104 rotatable on the shaft 100 and wrapped about approximately half of the cylinder. This further central port 102 is reversed relative to the port 98 and is therefore to the same side as the first-described port 92. A cylinder passage 105 extends from the slot 103 longitudinally within the cylinder to an opening in the surface exposed within the remaining sealed valve chamber 89. Such other end section of the cylinder has a sector-shaped slot 106 and port 107 like the slot 91 and port 92, as best shown in FIG. 8, but relatively reversed with respect to the central axial plane of the cylinder. The last slot 106 also communicates with the return passage 90, and a small passage 108 is shown as extending from the slot 106 to the space between the adjacent end of the cylinder and the housing. A fourth negator spring 109 on shaft 110 is wrapped on the cylinder over the port 107.

In the illustrated condition of the FIG. 4 valve, all of the ports 92, 98, 102 and 107 are fully closed respectively by the spring tapes 93, 99, 104 and 109. When the stem 79 is actuated to rotate the cylinder 78 from this position in either direction, two of these tapes will be more fully wrapped while the other two are simultaneously unwrapped, and the arrangement is such that the valve can thus be actuated to a first operative condition in which pressure fluid is supplied to the first work outlet and the second outlet is connected to the exhaust and a second position in which these relationships are reversed, that is, the second outlet receives the pressure fluid and the first outlet is connected to the exhaust. For example, with particular reference to FIGS. 5-8, if the cylinder is turned in a clockwise direction from the illustrated position, the tapes 93 and 104 are wrapped further in the same direction and maintain the ports 92 and 102 fully closed, while the other two tapes 99 and 109 are unwrapped and progressively open the ports 98 and 107. With this adjustment, pressure fluid supplied through the inlet 74 to the central chamber 87 will flow through the port 98 and passage 96 to the valve chamber 88 and the first outlet 75, the port 92 from this chamber to the exhaust 77 remaining closed. At the same time, the unwrapping of the tape 109 in the chamber 89 connects t-his chamber through port 107 to the exhaust passage 90, with the passage to the inlet chamber 87 remaining sealed at the port 102 by the tape 104. It will of course be understood that the degree of rotation determines the extent to which the flow is metered. Conversely, turning of the cylinder 78 from the illustrated condition in the counter-clockwise direction causes the pressure fluid to flow from the inlet chamber 87 through the now exposed port 102 and passage 105 to the second outlet chamber 89, while the first outlet chamber 88 is connected through exposure of the port 92 to'the return or exhaust passage 90. In such other adjusted condition, the tapes 99 and 109 are further wrapped to maintain the sealing of the communication 96 between inlet chamber 87 and the first outlet chamber 88 and of the exhaust port 107 of the second outlet chamber 89.

The mode of operation of the first described more fully designed form of the new valve will be exactly as set forth above, since the structural differences obviously do not have functional significance. In such first form, the openings in the first and second outlet chambers of the passages 52 and 54 selectively connected respectively through ports 43 and 46 to the inlet chamber 38 will of course be so located as not to be obscured in the full rotative adjustment of the cylinder 28, and this condition can be met with these openings approximately in the same planes as the ports 56 and 57 in the manner illustrated. This particular placement of such openings provides a reduction in the length of the cylinder as compared to the axial displacement thereof in the FIG. 4 form of the assembly. In both cases, it is important that each spring tape be tangential to the cylinder at the beginning of the associated port surface, that is, the end adjacent the spring, during the unwinding and the wrapping of the tape, and this relationship should be maintained notwithstanding a loss in the eifective outside diameter of the spring as a result of the unwinding. It may therefore be desirable in some installations, depending upon the size port employed and other dimensional factors, to locate the axis of each negator spring at a slight angular displacement from the illustrated position directly below the axis of the cylinder and toward the side away from the port with which it cooperates. For example, this would involve in FIG. 2 a slight shift of the axis of the spring 60 counter-clockwise a few degrees about the cylinder surface and a corresponding shift to the other side for the spring 64 in FIG. 3, with this adjustment requiring two separate shafts or shaft sections to be used in lieu of the single shaft 62 shown commonly serving both springs.

In the preferred embodiment of the new valve, it is desired that the noise of operation be held to a very low level, and it is for this purpose that the port assemblies have been shown and described as being in the form of screens or porous bodies. A sintered matrix can be employed for the purpose of any suitable material for a given installation, with the significant factor being the fragmenting of the area into a multitude of passages whether by a porous body, woven screen, perforate plate or the like.

It will be clearly seen that the new valve is of simple construction, with all metering and porting incorporated in a revolving cylinder the diameter of which is not critical. It is possible to utilize a very large meter area, with the design equally applicable to two-Way and three-way valves, and in all such assemblies, the force for operating the valve is uniform and relatively small, without undesirable sensitivity to pressure changes. This valve is also relatively insensitive to contamination and can be utilized without the elastomeric port seals again depending upon the operating conditions to be experienced and the level of performance desired. Most significantly, the sealing force on the wrapped portion of each tape is the result of an inherent characteristic of the particular form of the tape itself and the manner in which it is applied, the application actually involving nothing more than a mounting for rotation of the spring coil tape body and the described simple end attachment to the cylinder. The seal rings or gaskets about the port assemblies engaged by the tapes provide positive sealing, an effect which could also be realized by applying the sealing material directly to the tapes, with this modification being on the order of an obvious reversal for equivalent results.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. A rotary tape valve comprising housing means form- 'ing a fluid chamber, a valve member within a portion of said chamber having a substantially cylindrical surface exposed in the chamber, said valve member being provided with a port at said surface and a communicating flow passageway, flexible tape means for controlling the opening and closing of said port, said tape means being in the form of a spiral spring disposed with its axis parallel to that of said surface, the outer end portion of the spring being Wrapped on said surface by being deformed thereagainst reversely to the normal curve form thereof and fixedly attached at the end, and means for relatively rotating said member and tape means to variably wrap and unwrap the latter on the former and the port thereof.

2. A rotary tape valve as set forth in claim 1, wherein the port of the valve member comprises a plurality of relatively small passages commonly leading to said flow passageway.

3. A rotary tape valve as set forth in claim 1, wherein said valve member is a cylinder and the relative rotation is accomplished by turning said cylinder.

. '4. A rotary tape valve comprising housing means defining an inlet chamber and an outlet chamber respectively having inlet and outlet openings, a cylindrical valve member extending in spaced and sealed relation through said inlet and outlet chambers, the valve member having an interior flow passage between one surface opening in that portion within the inlet chamber and another sur-.

. face opening in the portion within the outlet chamber,

spiral spring means in the inlet chamber on an axis parallel to the axis of the valve member, the outer end portion of said spring means being reversely flexed and Wrapped about the valve member surface in which said one opening is located with its end attached to the member, and means for relatively rotating the member and spring means to wrap and unwrap the latter on the former and said one opening, whereby such relative rotation will 7. A rotary valve comprising housing means defining first and second chambers, a valving cylinder. extending through portions of the first and second chambers in sealed relation, the cylinder having a first internal flow passage extending from a first port in the surface of that section within the first chamber to an opening in the section within the second chamber, a second internal flow passage being provided in the cylinder extending from a second port in that section within the second chamber, a first flexible tape of spiral spring form in the first chamber rotatable on an axis parallel to that of the cylinder and with an end length reversely flexed about the cylinder surface portion in which the first port occurs, a second flexible tape of spiral spring form in the second chamber rotatable on an axis parallel to that of the cylinder and having an end length reversely flexed about the cylinder surface portion in which the second port occurs, the first and second ports being on opposite sides of the cylinder with respect to the tapes and the latter being wrapped in opposite directions on the cylinder, and means for rotating the cylinder to wrap and unwrap the tapes for opening and closing the ports.

8. A rotary valve as set forth in claim 7, wherein said first and second ports are formed by assemblies having a plurality of relatively small flow passages therethrough.

9. A rotary valve as set forth in claim 7, wherein elastomeric sealing gaskets surround the first and second ports for engagement by the flexible tapes.

References Cited UNITED STATES PATENTS 212,556 2/1879 Johnson 137625.3 X 601,634 4/1898 Cotter et a1. 1,138,994 5/1915 3 Steele 137-62512 2,180,173 11/1939 Share. 2,784,740 3/1957 Stageberg.

M. CARY NELSON, Primary Examiner.


Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US212556 *Jul 10, 1878Feb 25, 1879 Improvement in valves for hydraulic engines
US601634 *Dec 9, 1896Apr 5, 1898 Cock or faucet
US1138994 *Nov 1, 1913May 11, 1915Lawrence C SteeleValve.
US2180173 *Dec 20, 1937Nov 14, 1939Share BarnettFloat valve for hydraulic pumping systems
US2784740 *Oct 12, 1951Mar 12, 1957 stages erg
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3726313 *Jul 6, 1971Apr 10, 1973Aquamatic IncReciprocating valve
US3994314 *May 8, 1975Nov 30, 1976Hartley Ezra DServo regulator
US4182368 *Sep 8, 1977Jan 8, 1980Hartley E DalePressure regulator
US4729407 *May 13, 1987Mar 8, 1988Lew Hyok SDigital control valve
US4830041 *Oct 21, 1988May 16, 1989Institute Of Gas TechnologyReelable flow stopper for plugging fluid flow within a pipe
US6173640 *Dec 17, 1999Jan 16, 2001Sarcos, L.C.Band controlled valve/actuator
US6216724 *Jan 31, 2000Apr 17, 2001Ab Grundstenen (Metal Patent Whss Ab)Safety valve
US6253659 *Dec 7, 1999Jul 3, 2001Sarcos LcBand controlled valve/actuator
WO1998057075A1 *Jun 11, 1998Dec 17, 1998Sarcos IncBand controlled valve/actuator
U.S. Classification137/596, 251/901, 137/596.1, 137/625.2
International ClassificationF16K7/18
Cooperative ClassificationY10S251/901, F16K7/18
European ClassificationF16K7/18