CA1198651A - High pressure letdown valve - Google Patents
High pressure letdown valveInfo
- Publication number
- CA1198651A CA1198651A CA000421547A CA421547A CA1198651A CA 1198651 A CA1198651 A CA 1198651A CA 000421547 A CA000421547 A CA 000421547A CA 421547 A CA421547 A CA 421547A CA 1198651 A CA1198651 A CA 1198651A
- Authority
- CA
- Canada
- Prior art keywords
- valve
- throat
- plug
- flow path
- liquid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Details Of Valves (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A letdown valve is featured which maintains a smooth flow of furnace effluent, Liquid passing through the throat of the valve is throttled, and a portion is caused to flash to vapor. The valve is designed to allow for subsonic flow of the vapor under all process conditions. A quenching fluid is also added to the liquid passing through the throat in order to cool the liquid. The quenching fluid is directed in a manner to maintain operating freedom of the movable plug and enhance the valve service life.
A letdown valve is featured which maintains a smooth flow of furnace effluent, Liquid passing through the throat of the valve is throttled, and a portion is caused to flash to vapor. The valve is designed to allow for subsonic flow of the vapor under all process conditions. A quenching fluid is also added to the liquid passing through the throat in order to cool the liquid. The quenching fluid is directed in a manner to maintain operating freedom of the movable plug and enhance the valve service life.
Description
~r 1 ~
XIGH ~R~$SURE LETDOWN yALVE
1 FIELD OF THE INVE~TION
XIGH ~R~$SURE LETDOWN yALVE
1 FIELD OF THE INVE~TION
2 The invention relates to a letdown valve for vis-
3 breaker processing of liquids, and more particularly to
4 a letdown valve which will provide a smooth flow of effluent from a vis~reaker furnace.
6 BACK~KO~N~ OF THE lNV~N~l~iON
7 Visbreaking is a thermal cracking process for 8 converting heavy asphalt~like distillates into lighter, 9 more commercial products, such a~ fuel oil. Vishreaking is accomplished in a furnace operating at pressures of 11 from 400 to 1,600 psig, and temperatures of 700 to 900F.
12 Effluent from the furnace is passed through a 13 letdown valve, where the pressure and temperature is 14 drastically reduced. The severe reduction of the pressure and temperature makes extreme requirements upon the design 16 and operation of the letdown valve. If the letdown valve 17 is not designed properly, the flow of the furnace effluent 18 will back-up into the furnace or the valve will fail.
19 The letdown valve of this invention depressurizes and cools the furnace effluent, and maintains a smooth 21 flow of the liquid such tha~ noise and turbulence are 22 reduced as compared to other valve types.
23 As the effluent passes through the throat of the 24 valve, the liquid is throttled, and a portion is cau~ed to flash to vapor, the vapor having a greater volume than the 26 liquid, is then the controlling factor in the proper 27 hydrodynamic design of the valve. In order to obtain 28 continuous back-up-free flow, this inven~ion features 29 vapor leaving the outlet of the valve at sub-sonic speed.
The inven~ion has designed the outlet diam~ter of ~ufficient
6 BACK~KO~N~ OF THE lNV~N~l~iON
7 Visbreaking is a thermal cracking process for 8 converting heavy asphalt~like distillates into lighter, 9 more commercial products, such a~ fuel oil. Vishreaking is accomplished in a furnace operating at pressures of 11 from 400 to 1,600 psig, and temperatures of 700 to 900F.
12 Effluent from the furnace is passed through a 13 letdown valve, where the pressure and temperature is 14 drastically reduced. The severe reduction of the pressure and temperature makes extreme requirements upon the design 16 and operation of the letdown valve. If the letdown valve 17 is not designed properly, the flow of the furnace effluent 18 will back-up into the furnace or the valve will fail.
19 The letdown valve of this invention depressurizes and cools the furnace effluent, and maintains a smooth 21 flow of the liquid such tha~ noise and turbulence are 22 reduced as compared to other valve types.
23 As the effluent passes through the throat of the 24 valve, the liquid is throttled, and a portion is cau~ed to flash to vapor, the vapor having a greater volume than the 26 liquid, is then the controlling factor in the proper 27 hydrodynamic design of the valve. In order to obtain 28 continuous back-up-free flow, this inven~ion features 29 vapor leaving the outlet of the valve at sub-sonic speed.
The inven~ion has designed the outlet diam~ter of ~ufficient
5~
1 width. to o~.tai.n ~u~onic flow under all proces~s. condi.tions.
2 The i.nventï.on als.o feature~ a uni.que quenchl.ng 3 design for quenching the high temperature li~uid.
4 DISCUSSION OF RELATE~D ART
To the best of our ~nowledge, this is the first
1 width. to o~.tai.n ~u~onic flow under all proces~s. condi.tions.
2 The i.nventï.on als.o feature~ a uni.que quenchl.ng 3 design for quenching the high temperature li~uid.
4 DISCUSSION OF RELATE~D ART
To the best of our ~nowledge, this is the first
6 time an operative letdown valve has ~een designed for a
7 visbreaker process, wherein a portion of the furnace
8 effluent is throttled to a vapor without incurring normal g pro~lems of damagïng vi~ra~lon and noi.se.
10 13RIEF SUMMARY OF THE~ IENTION
11 The invention pertains to a letdown valve for 12 reducing the pressure of a li~uid. Th~ valve may be used 13 in visbreaking service and comprises in the most basic 14 defi.nition, the following four elements:
means defining a flow path for said li.quid;
16 means defining a valve throat disposed in said 17 flow path, said valve throat throttling said liquid 18 wherein at least a portion of said liquid wi.ll flash into 19 vapor;
means defining a high pressure valve inlet upstream 21 of said valve throat; and 22 means defining a low pre~sure valve outlet downstream 23 o said valve th.roat, said valve outlet having a diameter 24 of suffici~nt width ~o provïde fox a sub-sonic flow of said -vapor exiting said letdown valve.
26 Additionally, the valve comprises a mo~able plug for 27 controlling the flow of liqui.d across the throat. The plug 28 is supported and guided within a plug bushing, the plug 5~L
~ 3 ~
1 having channels runnïng therethrough. The channel~ intro-2 duce a quenching fluid into the flo~ path... Th.e. chann~ls 3 are concentrically arranged in the plug, and t~rmi`n~te 4 in curved vents~ wh.ïc~ direct the quenching flui.d out-~ardly from the plug axis. The quenc~ing fluid i~
6 introduced in the ~onnet porti.on of the letdown valve 7 and t~en passes through t~e plug.
8 It is an o~ject of thls invention to provide an g improved letdown valve for a vis~reakïng process;
It is another object of the invention to provide a 11 visbreaker letdown valve which introduce.s quenching fluid 12 .into t~e flow path stream;
13 It is a further object of this inv~ntion to provide 14 a letdown valve for a visbreaker process wh~rein the furnace effluent is throttled to a vapor in the throat 16 of the valve, and the vapor exits at sub-sonic velocity 17 to prevent effluent from backing-up at the inlet.
18 These and other objects of this invention will be 19 better understood and will become more apparent with ~o reference to the following detailed description, 21 con5idered in conjunction with the accompanying drawings.
23 Figure 1 is a sectional view of the visbreaker 24 letdown valve of this invention;
Figure 2 is a perspective, partial cut.away view of 26 the inventive valve of Figure l; and 27 Figure 3 is a plan Yiew of a rotational restraining 28 plate for the plug of the inventive valve of Figure 1.
s~
^ 4 ~
1 DETAI~E:D DESCRIPTION OF THE INVENTION
2 Generally speakin~, th~ inventlon feature.~ a 3 smooth flowing ~is~reaker letdown valve featuring a 4 quenching and t~rottling of furnace effluent.
Now referring to Figures 1 and 2~ a valve 10.. i5 6 s.h.own haviny a lower valve ~ody 11 and an upper bonnet 7 section 12.
8 The lower ~ody section 11 o-E valve 10 h~s an inlet
10 13RIEF SUMMARY OF THE~ IENTION
11 The invention pertains to a letdown valve for 12 reducing the pressure of a li~uid. Th~ valve may be used 13 in visbreaking service and comprises in the most basic 14 defi.nition, the following four elements:
means defining a flow path for said li.quid;
16 means defining a valve throat disposed in said 17 flow path, said valve throat throttling said liquid 18 wherein at least a portion of said liquid wi.ll flash into 19 vapor;
means defining a high pressure valve inlet upstream 21 of said valve throat; and 22 means defining a low pre~sure valve outlet downstream 23 o said valve th.roat, said valve outlet having a diameter 24 of suffici~nt width ~o provïde fox a sub-sonic flow of said -vapor exiting said letdown valve.
26 Additionally, the valve comprises a mo~able plug for 27 controlling the flow of liqui.d across the throat. The plug 28 is supported and guided within a plug bushing, the plug 5~L
~ 3 ~
1 having channels runnïng therethrough. The channel~ intro-2 duce a quenching fluid into the flo~ path... Th.e. chann~ls 3 are concentrically arranged in the plug, and t~rmi`n~te 4 in curved vents~ wh.ïc~ direct the quenching flui.d out-~ardly from the plug axis. The quenc~ing fluid i~
6 introduced in the ~onnet porti.on of the letdown valve 7 and t~en passes through t~e plug.
8 It is an o~ject of thls invention to provide an g improved letdown valve for a vis~reakïng process;
It is another object of the invention to provide a 11 visbreaker letdown valve which introduce.s quenching fluid 12 .into t~e flow path stream;
13 It is a further object of this inv~ntion to provide 14 a letdown valve for a visbreaker process wh~rein the furnace effluent is throttled to a vapor in the throat 16 of the valve, and the vapor exits at sub-sonic velocity 17 to prevent effluent from backing-up at the inlet.
18 These and other objects of this invention will be 19 better understood and will become more apparent with ~o reference to the following detailed description, 21 con5idered in conjunction with the accompanying drawings.
23 Figure 1 is a sectional view of the visbreaker 24 letdown valve of this invention;
Figure 2 is a perspective, partial cut.away view of 26 the inventive valve of Figure l; and 27 Figure 3 is a plan Yiew of a rotational restraining 28 plate for the plug of the inventive valve of Figure 1.
s~
^ 4 ~
1 DETAI~E:D DESCRIPTION OF THE INVENTION
2 Generally speakin~, th~ inventlon feature.~ a 3 smooth flowing ~is~reaker letdown valve featuring a 4 quenching and t~rottling of furnace effluent.
Now referring to Figures 1 and 2~ a valve 10.. i5 6 s.h.own haviny a lower valve ~ody 11 and an upper bonnet 7 section 12.
8 The lower ~ody section 11 o-E valve 10 h~s an inlet
9 13, wh.ich receives the furnace effluent at pressures of between 400 and 1, 6ao psig and temperatures o~ approxi-11 mately 700 to ~00F.
12 The effluent enters the inlet 13 and is throttled 13 as it flows past ~hroat area 14. The ef~luent liquid 14 will partially flash into a vapor as it exits the throat area and enters the diffusing area 15 of the valve.
16 The vapor exits the outlet 16 of the valve at sub-sonic 17 velocity due to t~e wide di.ameter of outlet 16. It will 18 be noted that the outlet 16 i5: almost twice the diameter ]g of th~ inlet 13. The exiting of the vapor and li.quid of the effluent from outlet 16 at sub-sonic spee.d assures 21 that the furnace effluent wïll not back-up into the 22 furnace. Alsol the inventive design insures a steady 23 flow and minimum pressure recovery which is quï.eter than 24 other similar flow designs.
A movable plug 17 is dispo~ed adjacent the throat 2k area 14, and is used to control the flow acros~ th.e 27 throat 14. The flow will generally surround th.e plug 17 28 as the liquïd diffuses UpOll exlting th.e throat.
29 The plug 17 comprises ~ head portion 18 for con-trollin~ flow through the throat area 14 and a shank 31 19, stem 35, turnbuckle 31 and spindle 36. The shank 19 65~.
~ 5 -l is guided and supported for ~ovement by a h~ ;ng 20.
2 The ~ushing 2~ generally has a len~th sufficient to 3 support the s~an~ 19 ~ro~ hrea~ing but not so long that 4 coke build-up on th~ internal wall surfaces 21 of the bushing 20 will cause binding of th.e s~ank l9 against 6 movement. The bus~ing contact will generally have a 7 length to diameter ratio of approximately 1.5.
8 The shank 19 has a plurality of channels 22 concen-9 trically arranged, therein, and which run completely la through. the shank 19. The channels convey quench.ing ll flui.d fro~ the quenching fluid inlet 23 in the bonnet 12.
12 The channels each terminate in curved vents 24, 13 wh.ich direct the ~u~nching fluid into the diffusing flow 14 path of the furnace effluent.
The plug 17 is generally moved by a gear-reduced 16 motor drive (not shown). In order to prevent the rota-17 tion o~ the spindle 36 as it is moved within the valve 18 body, a retaining ring 26 is bolted in place in a yoke 19 portion 27 of the valve l~, wh.ich itself is. bolted to bonnet 12~
21 The retaining ring 26 has two permanent keys 28 22 which align with keyway groves 29 of spindle 36.
23 The spindle 36 is joined to the stem 35. A turn-?4 buckle 31 connects the spindle and stem portions of plug 17. This turnbuckle pre~ents failure of the s.h.ank 19 26 and ~tem 35 from vibrational causes and allows continuous 27 vert.i.cal ad~ustment of shank length and hence plug con-28 tact with the valve seat even when the plug is mounted 29 within the valve.
Both the retaining ri.ng 26 and thP turnbuckle 31 65~
- 6 ~
1 pre~ent undue strain from b.eing exerted upon spindle 36.
2 Such.strain was often a cause of failure in earli.er 3 desï.gns.
4 In order to pre~ent coke build~up and erosion damage to internal diffuser area surface5, the walls 33 6 of the diffuser area 15 are coated with.StelliteO The 7 outlet walls 34 are coated with. tungsten car~ide to 8 pxe~ent erosion hy t~e rapidly moving gases and liquid.
~ The head 18 of plug 17 is also coated with ctellite to
12 The effluent enters the inlet 13 and is throttled 13 as it flows past ~hroat area 14. The ef~luent liquid 14 will partially flash into a vapor as it exits the throat area and enters the diffusing area 15 of the valve.
16 The vapor exits the outlet 16 of the valve at sub-sonic 17 velocity due to t~e wide di.ameter of outlet 16. It will 18 be noted that the outlet 16 i5: almost twice the diameter ]g of th~ inlet 13. The exiting of the vapor and li.quid of the effluent from outlet 16 at sub-sonic spee.d assures 21 that the furnace effluent wïll not back-up into the 22 furnace. Alsol the inventive design insures a steady 23 flow and minimum pressure recovery which is quï.eter than 24 other similar flow designs.
A movable plug 17 is dispo~ed adjacent the throat 2k area 14, and is used to control the flow acros~ th.e 27 throat 14. The flow will generally surround th.e plug 17 28 as the liquïd diffuses UpOll exlting th.e throat.
29 The plug 17 comprises ~ head portion 18 for con-trollin~ flow through the throat area 14 and a shank 31 19, stem 35, turnbuckle 31 and spindle 36. The shank 19 65~.
~ 5 -l is guided and supported for ~ovement by a h~ ;ng 20.
2 The ~ushing 2~ generally has a len~th sufficient to 3 support the s~an~ 19 ~ro~ hrea~ing but not so long that 4 coke build-up on th~ internal wall surfaces 21 of the bushing 20 will cause binding of th.e s~ank l9 against 6 movement. The bus~ing contact will generally have a 7 length to diameter ratio of approximately 1.5.
8 The shank 19 has a plurality of channels 22 concen-9 trically arranged, therein, and which run completely la through. the shank 19. The channels convey quench.ing ll flui.d fro~ the quenching fluid inlet 23 in the bonnet 12.
12 The channels each terminate in curved vents 24, 13 wh.ich direct the ~u~nching fluid into the diffusing flow 14 path of the furnace effluent.
The plug 17 is generally moved by a gear-reduced 16 motor drive (not shown). In order to prevent the rota-17 tion o~ the spindle 36 as it is moved within the valve 18 body, a retaining ring 26 is bolted in place in a yoke 19 portion 27 of the valve l~, wh.ich itself is. bolted to bonnet 12~
21 The retaining ring 26 has two permanent keys 28 22 which align with keyway groves 29 of spindle 36.
23 The spindle 36 is joined to the stem 35. A turn-?4 buckle 31 connects the spindle and stem portions of plug 17. This turnbuckle pre~ents failure of the s.h.ank 19 26 and ~tem 35 from vibrational causes and allows continuous 27 vert.i.cal ad~ustment of shank length and hence plug con-28 tact with the valve seat even when the plug is mounted 29 within the valve.
Both the retaining ri.ng 26 and thP turnbuckle 31 65~
- 6 ~
1 pre~ent undue strain from b.eing exerted upon spindle 36.
2 Such.strain was often a cause of failure in earli.er 3 desï.gns.
4 In order to pre~ent coke build~up and erosion damage to internal diffuser area surface5, the walls 33 6 of the diffuser area 15 are coated with.StelliteO The 7 outlet walls 34 are coated with. tungsten car~ide to 8 pxe~ent erosion hy t~e rapidly moving gases and liquid.
~ The head 18 of plug 17 is also coated with ctellite to
10. prevent coke ~uild-up thereon.
11 ~.aving thus descri~ed this in~ention ~hat i5
12 desired to ~e protected ~ Letters Patent i5 presented
13 by the following appended claims.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A letdown valve for reducing the pressure of a liquid, comprising:
means defining a flow path for said liquid;
means defining a valve throat disposed in said flow path, said valve throat throttling said liquid where-in at least a portion of said liquid will flash into vapor;
means defining a high pressure valve inlet upstream of said valve throat;
means defining a low pressure valve outlet down-stream of said valve throat;
a movable elongated cylindrical plug disposed adjacent said throat; and bushing means including an end portion projecting into said flow path fox supporting and guiding said plug for axial movement therein, said plug including a plurality of channels running axially therein for introducing quenching fluid into said flow path, said channels being arranged concentrically in an annular array within said plug and each having an axis extending parallel to the axis of said plug and wherein each of said channels terminates in a curved vent portion for directing said quenching fluid radially outward into said flow path.
adjacent said bushing means end portion.
means defining a flow path for said liquid;
means defining a valve throat disposed in said flow path, said valve throat throttling said liquid where-in at least a portion of said liquid will flash into vapor;
means defining a high pressure valve inlet upstream of said valve throat;
means defining a low pressure valve outlet down-stream of said valve throat;
a movable elongated cylindrical plug disposed adjacent said throat; and bushing means including an end portion projecting into said flow path fox supporting and guiding said plug for axial movement therein, said plug including a plurality of channels running axially therein for introducing quenching fluid into said flow path, said channels being arranged concentrically in an annular array within said plug and each having an axis extending parallel to the axis of said plug and wherein each of said channels terminates in a curved vent portion for directing said quenching fluid radially outward into said flow path.
adjacent said bushing means end portion.
2. A letdown valve in accordance with claim 1 wherein said valve throat includes a convergent portion upstream of said throat and a divergent portion down-stream of said throat.
3. A letdown valve in accordance with claim 2 wherein said plug further includes a convex domed end portion adjacent said throat.
4. The letdown valve of claim 1, wherein said plug includes a stem and spindle, and further including means for preventing said spindle from rotating.
5. The letdown valve of claim 1, wherein said plug includes an elongated stem, and means for adjusting the lift position of said plug.
6. A letdown valve for reducing the pressure of a liquid, comprising:
means defining a flow path for said liquid;
means defining a valve throat disposed in said flow path, said valve throat throttling said liquid wherein at least a portion of said liquid will flash into vapor;
means defining a high pressure valve inlet upstream of said valve throat;
means defining a low pressure valve outlet down-stream of said valve throat, said valve outlet having a cross-sectional area relative to said throat area and differential pressure across said valve to provide for a sub-sonic flow of said vapor exiting said letdown valve;
a movable elongated cylindrical plug disposed adjacent said throat;
bushing means including an end portion for supporting and guiding said plug for movement, said plug including a plurality of channels running axially therein for introducing quenching fluid into said flow path, said channels being arranged concentrically in an annular array within said plug and each having an axis extending parallel to the axis of said plug and wherein each of said channels terminates exteriorly of said bushing means in a curved vent portion for directing said quenching fluid radially outward into said flow path adjacent said bushing means end portion.
means defining a flow path for said liquid;
means defining a valve throat disposed in said flow path, said valve throat throttling said liquid wherein at least a portion of said liquid will flash into vapor;
means defining a high pressure valve inlet upstream of said valve throat;
means defining a low pressure valve outlet down-stream of said valve throat, said valve outlet having a cross-sectional area relative to said throat area and differential pressure across said valve to provide for a sub-sonic flow of said vapor exiting said letdown valve;
a movable elongated cylindrical plug disposed adjacent said throat;
bushing means including an end portion for supporting and guiding said plug for movement, said plug including a plurality of channels running axially therein for introducing quenching fluid into said flow path, said channels being arranged concentrically in an annular array within said plug and each having an axis extending parallel to the axis of said plug and wherein each of said channels terminates exteriorly of said bushing means in a curved vent portion for directing said quenching fluid radially outward into said flow path adjacent said bushing means end portion.
7. A letdown valve in accordance with claim 6 wherein said valve includes a convergent portion upstream of said throat and a divergent portion downstream of said throat.
8. A letdown valve in accordance with claim 7 wherein said plug further includes a convex domed end portion positioned adjacent said throat.
9. A visbreaker letdown valve for reducing the pressure of a liquid, comprising:
means defining a flow path for said liquid;
means defining a valve throat disposed in said flow path, said valve throat throttling said liquid wherein at least a portion of said liquid will flash into vapor;
means defining a high pressure valve inlet up-stream of said valve throat and including a convergent portion upstream of said throat and a divergent portion downstream of said throat;
means defining a low pressure valve outlet down-stream of said valve throat, said valve outlet having a cross-sectional area relative to said throat area and differential pressure across said valve to provide for a sub-sonic flow of said vapor exiting said letdown valve;
a moveable elongated cylindrical plug disposed adjacent said throat;
bushing means including an end portion projecting into said flow path for supporting and guiding said plug for axial movement therein, said plug including a convex domed end portion adjacent said throat and a plurality of channels running axially therein for introducing quenching fluid into said flow path, said channel being arranged concentrically in an annular array within said plug and each having an axis extending parallel to the axis of said plug and wherein each of said channels terminates in a curved vent portion for directing said quenching fluid radially outward into said flow path adjacent said bushing means end portion.
means defining a flow path for said liquid;
means defining a valve throat disposed in said flow path, said valve throat throttling said liquid wherein at least a portion of said liquid will flash into vapor;
means defining a high pressure valve inlet up-stream of said valve throat and including a convergent portion upstream of said throat and a divergent portion downstream of said throat;
means defining a low pressure valve outlet down-stream of said valve throat, said valve outlet having a cross-sectional area relative to said throat area and differential pressure across said valve to provide for a sub-sonic flow of said vapor exiting said letdown valve;
a moveable elongated cylindrical plug disposed adjacent said throat;
bushing means including an end portion projecting into said flow path for supporting and guiding said plug for axial movement therein, said plug including a convex domed end portion adjacent said throat and a plurality of channels running axially therein for introducing quenching fluid into said flow path, said channel being arranged concentrically in an annular array within said plug and each having an axis extending parallel to the axis of said plug and wherein each of said channels terminates in a curved vent portion for directing said quenching fluid radially outward into said flow path adjacent said bushing means end portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000421547A CA1198651A (en) | 1983-02-14 | 1983-02-14 | High pressure letdown valve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000421547A CA1198651A (en) | 1983-02-14 | 1983-02-14 | High pressure letdown valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1198651A true CA1198651A (en) | 1985-12-31 |
Family
ID=4124568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000421547A Expired CA1198651A (en) | 1983-02-14 | 1983-02-14 | High pressure letdown valve |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1198651A (en) |
-
1983
- 1983-02-14 CA CA000421547A patent/CA1198651A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4383553A (en) | Visbreaker letdown valve | |
| DE19615237C2 (en) | Exhaust gas turbocharger for an internal combustion engine | |
| US6883807B2 (en) | Multidirectional turbine shim seal | |
| US5862666A (en) | Turbine engine having improved thrust bearing load control | |
| US5803119A (en) | Fluid flow control device | |
| US5605172A (en) | Fluid control valve and method for subjecting a liquid to a controlled pressure drop | |
| US8020383B2 (en) | Steam valve and generator set | |
| EP1334300B1 (en) | High-stability valve arrangement for a governor valve | |
| EP0838617A1 (en) | Valve Assembly | |
| EP1736635A2 (en) | Air transfer system between compressor and turbine of a gas turbine engine | |
| US7784279B2 (en) | Steam valve and steam turbine plant | |
| GB2169059A (en) | Valve for high-pressure, dust-laden gases | |
| AU656790B2 (en) | An improved flow control system | |
| EP1495247A1 (en) | Low noise fluid control valve | |
| US4147028A (en) | Jet engine thrust reverser and cowl structure | |
| US4766924A (en) | Pressure relief valve | |
| EP0116735A1 (en) | A high pressure letdown valve | |
| US5380470A (en) | Method and apparatus for reducing the pressure and temperature of steam in a steam conditioning valve | |
| CA1198651A (en) | High pressure letdown valve | |
| JPS5918588B2 (en) | Vibration resistant valve | |
| US5983626A (en) | Injection head for rocket engines | |
| WO1996005128A1 (en) | Fluidising apparatus | |
| AU640678B2 (en) | Throttling valve | |
| AU1550995A (en) | Steam conditioning butterfly valve | |
| WO1995020733A1 (en) | Radiator valve |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |