Claims
- 1. A device for regulating the flow of fluid, the device comprising:
- a path through which fluid passes from an input to an output;
- a piston-mounting structure;
- a piston movably mounted on the piston-mounting structure so that the piston may constrict the path at a constriction point;
- a dashpot having a first portion rigidly attached to the piston and a second portion rigidly attached to the piston-mounting structure, the two portions of the dashpot defining a chamber of varying volume and being so dimensioned as to permit only restricted fluid communication to the dashpot chamber;
- a reference chamber defined by the piston-mounting structure and the piston movably mounted thereon; and
- buffering fluid means for supplying a buffering fluid to a point between the piston and the piston-mounting structure such that a first portion of the buffering fluid flows into the path and a second portion of the buffering fluid flows into the reference chamber.
- 2. A device as set forth in claim 1 wherein the piston includes a central portion and a rim disposed in the path for constricting the path between the rim of the piston and the constriction point.
- 3. A device as set forth in claim 1 wherein the dashpot prevents the piston from oscillating at a harmonic frequency.
- 4. A device for regulating the flow of fluid, the device comprising:
- a path through which fluid passes from an input to an output;
- a piston-mounting structure;
- a piston movably mounted on the piston-mounting structure, the piston having a distal face exposed to a reference pressure, and a frontal face exposed to fluid in the path and extending substantially across the input so as to constrict the path at a constriction point;
- a dashpot having a first portion rigidly attached to the piston and a second portion rigidly attached to the piston-mounting structure, the two portions of the dashpot defining a chamber of varying volume and being so dimensioned as to permit only restricted fluid communication to the dashpot chamber;
- a reference chamber defined by the piston-mounting structure and the piston movably mounted thereon; and
- buffering fluid means for supplying a buffering fluid to a point between the piston and the piston-mounting structure such that a first portion of the buffering fluid flows into the path and a second portion of the buffering fluid flows into the reference chamber.
- 5. A device for regulating the flow of fluid, the device comprising:
- a path through which fluid passes from an input to an output;
- a piston-mounting structure;
- a piston movably mounted on the piston-mounting structure so that the piston may constrict the path at a constriction point when the piston moves up relative to the piston-mounting structure; and
- a dashpot having a first portion rigidly attached to the piston and a second portion rigidly attached to the piston-mounting structure, the two portions of the dashpot defining a chamber of varying volume and being so dimensioned as to permit only restricted fluid communication to the dashpot chamber;
- reference chamber defined by the piston-mounting structure and the piston movably mounted thereon; and
- buffering fluid means for supplying a buffering fluid to a point between the piston and the piston-mounting structure such that a first portion of the buffering fluid flows into the path and a second portion of the buffering fluid flows into the reference chamber.
- 6. A device for regulating the flow of fluid, the device comprising:
- a path through which fluid passes from an input to an output;
- a piston-mounting structure;
- a piston movably mounted on the piston-mounting structure so that the piston may constrict the path at a constriction point, the piston having a frontal face and a distal face;
- a dashpot having a first portion rigidly attached to the piston and a second portion rigidly attached to the piston-mounting structure, the two portions of the dashpot defining a chamber of varying volume and being so dimensioned as to permit only restricted fluid communication to the dashpot chamber; and
- buffering fluid means for supplying a buffering fluid to a point between the piston and the piston-mounting structure such the a first portion of the buffering fluid flows into the path and a second portion of the buffering fluid flows into the reference chamber;
- wherein the frontal face and the distal face of the piston are independent of the dashpot.
RELATED U.S. APPLICATIONS
This application is a divisional of application Ser. No. 08/141,498, filed Oct. 22, 1993 now U.S. Pat. No. 5,450,873, which is a continuation-in-part of applications Ser. Nos. 07/965,909, now abandoned, and 07/965,907 (now issued as U.S. Pat. No. 5,320,124), both of which were filed Oct. 23, 1992, and both of which are continuations-in-part of applications Ser. Nos. 07/850,767 (now issued as U.S. Pat. No. 5,251,654), Ser. No. 07/851,017 (now issued as U.S. Pat. No. 5,255,710), Ser. No. 07/852,084 (now issued as U.S. Pat. No. 5,255,709) and Ser. No. 07/851,016 (now issued as U.S. Pat. No. 5,220,940), all filed Mar. 13, 1992, and all of which are continuations-in-part of application Ser. No. 07/669,746, filed Mar. 15, 1991, now abandoned, and which is a continuation-in-part of application Ser. No. 07/405,835, filed Sep. 11, 1989 and issued Mar. 19, 1991 as U.S. Pat. No. 5,000,221, which is a continuation-in-part of application Ser. No. 07/178,505, filed Apr. 7, 1988, now abandoned. The present application is also a continuation-in-part of application Ser. No. 08/126,151, filed Sep. 23, 1993, now U.S. Pat. No. 5,456,280. All these applications are hereby incorporated herein by reference.
US Referenced Citations (63)
Foreign Referenced Citations (12)
Number |
Date |
Country |
275361 |
Jul 1988 |
EPX |
532356 |
Aug 1931 |
DEX |
2216498 |
Aug 1974 |
DEX |
2309918 |
Nov 1976 |
DEX |
2389933 |
Dec 1978 |
DEX |
551043 |
May 1974 |
CHX |
957118 |
May 1964 |
GBX |
1429932 |
Mar 1976 |
GBX |
1519515 |
Jul 1978 |
GBX |
2236165 |
Mar 1991 |
GBX |
WO9216884 |
Oct 1992 |
WOX |
WO9216885 |
Oct 1992 |
WOX |
Non-Patent Literature Citations (1)
Entry |
Amminger, W.L., "Computational Valve Analysis," Proceedings of the Second National Fluid Power System and Controls Conference (University of Wisconsin, May 21-23, 1975). |
Divisions (1)
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Date |
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Parent |
141498 |
Oct 1993 |
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Continuation in Parts (9)
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Number |
Date |
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Parent |
965909 |
Oct 1992 |
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Parent |
965907 |
Oct 1992 |
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Parent |
850767 |
Mar 1992 |
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Parent |
851017 |
Mar 1992 |
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Parent |
852084 |
Mar 1992 |
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Parent |
851016 |
Mar 1992 |
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Parent |
669746 |
Mar 1991 |
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Parent |
405835 |
Sep 1989 |
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Parent |
178505 |
Apr 1988 |
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