Claims
- 1. An actuator configuration including:
- an actuating cylinder having a piston arranged to be driven by actuating fluid along a stroke path therewithin;
- a valve means for controlling the flow of actuating fluid to a first side of the piston; and
- means responsive to the piston reaching a predetermined point along the stroke path to actuate the valve means to stop the flow of actuating fluid to the first side of the piston;
- wherein the pressure of said actuating fluid on said first side of said piston upon actuation of said valve means is at least sufficient to substantially maintain said piston in a first predetermined position along the stroke path, and is a reduced pressure as compared to a system pressure able to be applied to a second side of said piston to drive said piston in the opposite direction along the stroke path.
- 2. An actuator configuration according to claim 1, wherein the valve means is arranged such that if there is leakage of said actuating fluid from said first side of the piston, said valve means will operate to provide a flow of actuating fluid to said first side of the piston to compensate for said leakage.
- 3. An actuator configuration according to claim 1, wherein said responsive means includes a portion of said valve means engaged by said piston when at said predetermined point to hold said valve means in a position where the flow of actuating fluid to said first side of said piston is stopped.
- 4. An actuator configuration according to claim 3, wherein said valve means is arranged to allow a flow of actuating fluid to said first side of said piston whenever said piston is disengaged from said portion of said valve means, whereby if there is a leakage of actuating fluid from said first side of said piston which would allow said piston to move and disengage from said portion of said valve means, actuating fluid would flow to said first side of said piston to maintain said piston substantially at or adjacent said first predetermined position and thereby prevent inadvertent stroking of said piston.
- 5. An actuator configuration according to claim 3, wherein said valve means includes a poppet valve and said portion of said responsive means includes a stem arranged to be contacted by said piston when it is located at said predetermined point.
- 6. An actuator configuration according to claim 1, wherein the valve means is mounted within said actuating cylinder.
- 7. An actuator configuration according to claim 1, wherein the actuating cylinder is a crust breaker actuating cylinder and the piston is connected to a piston rod which is connected to or integrally formed with a device for breaking the crust on a smelter pot.
- 8. An actuator configuration according to claim 1 further comprising means to control the rate of flow of actuating fluid to said first side of said piston.
- 9. An actuator configuration according to claim 8, wherein the control means comprises a check valve, a restrictor or an adjustable control valve which acts as a restrictor when the actuating fluid is flowing to said first side of said piston, and which enables fast exhaust when the actuating fluid is flowing to said second side of said piston.
- 10. An actuator configuration according to claim 1, wherein said predetermined point is at or adjacent an end of the stroke path of the piston.
- 11. An actuator configuration according to claim 1, wherein the responsive means acts remotely from the piston, triggered by the piston or otherwise.
- 12. An actuator configuration according to claim 11, wherein if there is a leakage of actuating fluid from said first side of said piston, said piston moves and said valve means responds thereto to allow a flow of actuating fluid to said first side of said piston to thereby maintain said piston substantially at or adjacent said first predetermined position and thereby to prevent inadvertent stroking of said piston.
- 13. A method of operating a crust breaker actuator of a smelter pot including:
- providing a flow of actuating fluid at a system pressure to one side of a piston of said actuator so as to drive said piston toward said pot and thereby to drive a crust breaker through the crust of said pot;
- providing a flow of actuating fluid to another side of said piston so as to drive said piston away from said pot and to release said crust breaker from the crust of said pot; and
- stopping the flow of actuating fluid to said other side of said piston once said crust breaker reaches a predetermined point along the stroke path of the piston, wherein the pressure of said actuating fluid on said other side of the piston after said stopping of the flow is at least sufficient to substantially maintain said piston in a first predetermined position along the stroke path, and is a reduced pressure compared to said system pressure of the actuating fluid.
- 14. A method according to claim 13 wherein the flow of actuating fluid to said other side is stopped by triggering a valve means which controls the flow of actuating fluid to said other side.
- 15. A crustbreaker actuator configuration including:
- a crustbreaker actuating cylinder having a piston arranged to be driven by compressed air along a stroke path therewithin, said piston being connected to a piston rod which is connected to or integrally formed with a device for breaking the crust in a smelter pot when the piston is driven by compressed air in a first direction along said stroke path;
- conduit means by which compressed air is delivered during operation to a first side of the piston, including valve means for controlling the flow of the compressed air to said first side of the piston, which flow is effective to drive the piston in a second direction opposite said first direction for retracting said crust breaking device from the crust;
- means responsive to the piston reaching a predetermined point when traveling in said second direction along the stroke path to actuate the valve means whereby to stop the flow of air to said first side of the piston, at which predetermined point said crust breaking device is clear of the crust; and
- wherein the conduit means is such that the pressure of said air on said first side of said piston upon actuation of said valve means is at least sufficient to substantially maintain said piston in a first predetermined position along the stroke path and thus maintain said crust breaking device in a position clear of the crust.
- 16. A crustbreaker actuator configuration according to claim 15, wherein the pressure of said air on said first side of said piston upon actuation of said valve means is reduced pressure as compared to a system pressure able to be applied to a second side of said piston to drive said piston in said first direction along the stroke path.
- 17. A crustbreaker actuator configuration according to claim 15, wherein the valve means is arranged such that if there is leakage of said compressed air from said first side of the piston, said valve means will operate to provide a flow of compressed air to said first side of the piston to compensate for said leakage.
- 18. A crustbreaker configuration according to claim 15, wherein said responsive means includes a portion of said valve means engaged by said piston when at said predetermined point whereby to hold said valve means in a position where the flow of compressed air to said first side of said piston is stopped.
- 19. A crustbreaker actuator configuration according to claim 18, wherein said valve means includes a poppet valve and said portion of said responsive means includes a stem arranged to be contracted by said piston when it is located at said predetermined point.
- 20. A crustbreaker actuator configuration according to claim 18, wherein if there is a leakage of compressed air from said first side of said piston, said piston moves and disengages from said portion of said valve means, whereby said valve means allows a flow of compressed air to said first side of said piston to thereby maintain said piston substantially at or adjacent said first predetermined position and thereby prevents inadvertent stroking of said piston.
- 21. A crustbreaker actuator configuration according to claim 15, wherein the valve means is mounted within said actuating cylinder.
- 22. A crustbreaker actuator configuration according to claim 15, wherein said conduit means includes means to control the rate of flow of said compressed air to said first side of said piston.
- 23. A crustbreaker configuration according to claim 22, wherein the control means comprises a check valve, a restrictor or an adjustable control valve which acts as a restrictor when said crustbreaking device is being retracted from said pot and which enables fast exhaust when said crustbreaking device is driven towards said pot.
- 24. A crustbreaker configuration according to claim 15, wherein said predetermined point is at or adjacent an end of the stroke path of the piston.
- 25. A crustbreaker configuration according to claim 15, wherein the responsive means acts remotely from the piston, triggered by the piston or otherwise.
- 26. A crustbreaker configuration according to claim 25, wherein if there is a leakage of compressed air from said first side of said piston, said piston moves and said valve means responds thereto to allow a flow of compressed air to said first side of said piston to thereby maintain said piston substantially at or adjacent said first predetermined position and thereby to prevent inadvertent stroking of said piston.
- 27. A method of operating a crustbreaker actuator of a smelter pot including:
- providing a flow of compressed air to one side of a piston of said actuator so as to drive said piston toward said pot and thereby to drive a crustbreaker device through the crust of said pot;
- providing a flow of compressed air to another side of said piston so as to drive said piston away from said pot and to release said crustbreaker device from the crust of said pot; and
- stopping the flow of compressed air to said other side of said piston once said crustbreaker device reaches a predetermined point along the stroke path of the piston, wherein the pressure of said compressed air on said other side of the piston after said stopping of the flow is at least sufficient to substantially maintain said piston in a first predetermined position along the stroke path.
- 28. A method according to claim 27, wherein the flow of compressed air to said other side is stopped by triggering a valve means which controls the flow of compressed air to said other side.
Priority Claims (2)
Number |
Date |
Country |
Kind |
PM6831 |
Jul 1994 |
AUX |
|
PN2536 |
Apr 1995 |
AUX |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/765,978, filed Jan. 15, 1997, now abandoned.
US Referenced Citations (15)
Foreign Referenced Citations (4)
Number |
Date |
Country |
26 29 564 A1 |
Jan 1978 |
DEX |
28 50 237 A1 |
May 1980 |
DEX |
30 22 490 A1 |
Dec 1981 |
DEX |
2 188 984 |
Oct 1987 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Exhibit D "Piping Diagram For Self-Reciprocating Cyclinders,"(3 pages) (undated). (No Date). |
Continuations (1)
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Number |
Date |
Country |
Parent |
765978 |
Jan 1997 |
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