1. A device for a dynamic sealing system for a preferably submerged pump connectable to a process fluid conduit by a process inlet line and a process outlet line for pressurising a produced fluid, comprising at least one feed line running from a barrier fluid source in towards the dynamic sealing system, wherein it comprises a first valve device arranged in the feed line, which is provided to open or close the feed line and a second valve device arranged such that in an open position it opens a first bypass line that runs from a point on the feed line between the first valve device and the pump and a low-pressure source at the pump in order to relieve the pressure in a barrier fluid in the sealing system, and a control unit having means for receiving actual working pressure conditions around the pump, where the valve devices are connected to the control unit which controls them in accordance with the working pressure conditions of the pump.
2. A device according to claim 1, wherein the low-pressure source near the pump is formed by the process fluid conduit.
3. A device according to claim 1, wherein the first valve device is located in proximity to the pump or at a point where the desired static pressure is downstream of the valve device.
4. A device according to claim 1, wherein the first bypass line runs from the feed line to the process inlet line.
5. A device according to claim 3, wherein it comprises a third valve device, which in one position opens a second bypass line running between a point on the feed line ahead of the first valve device and the process inlet line.
6. A device according to claim 5, wherein the second valve device is connected to the second bypass line between the third valve device and the process inlet line, so that in one position it opens the first bypass line and closes the second bypass line, and in a second position it closes the first bypass line and keeps the second bypass line open.
7. A device according to claim 5, wherein it comprises a valve means, which in one position opens a third bypass line from a point on the feed line ahead of the first valve device to the process inlet line.
8. A device according to claim 1, wherein at least one accumulator is attached to the feed line between the first valve device and the pump.
9. A device according to claim 1, wherein at least one nozzle is arranged in the feed line, between the first valve device and the pump andor the process inlet line.
10. A device according to claim 1, wherein it provides a connection between the feed line for the barrier fluid and a cooling system for a motor connected to the pump, so that the barrier fluid can be used as a cooling fluid.
11. A device according to claim 10, wherein arranged in the cooling system is a circulation impeller which is connected to a motor shaft so that the speed of the circulation impeller is directly controlled by the rotation of the motor shaft.
12. A device according to claim 10, wherein arranged in the barrier fluid circuit for cooling is at least one cooling unit and at least one filter unit.
13. A device according to claim 12, wherein a cooling unit is arranged in parallel with a filter unit.
14. A device according to claim 1, wherein the feed line leads to two feed lines each comprising a first valve device and a second valve device arranged in a bypass line, for supply of a barrier fluid to the sealing system at respectively a suction side and an outlet side of a pump or alternatively two separate pumps.
15. A device according to claim 1, wherein the barrier fluid source is arranged at a surface of fluid in which the pump is submerged, is submerged in the fluid in which the pump is submerged, or is formed of the fluid in which the pump is submerged.
16. A method for reducing the barrier pressure in a sealing system for a pump, with a barrier fluid feed line between a source for barrier fluid and the pump and where in the feed line there is arranged a first valve device and a second valve device is provided between the first valve device and the pump, the second valve device connecting a bypass line between the feed line and the process fluid conduit of the pump, wherein the first valve device is put in a closed state, so that the feed line is shut off, the second valve device is opened so that an open passage is obtained via the bypass line between the feed line and thus the sealing system and the process inlet of the pump, and barrier fluid is bled off to the process inlet of the pump.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A leak detecting apparatus comprising:
an evaporation system in which a fuel vapor evaporated in a fuel tank flows, the evaporation system including a canister for adsorbing the fuel vapor in such a way that the fuel vapor can be desorbed;
a measure passage;
a pump connecting with the canister through the measure passage;
a pressure sensor for measuring a pressure in the measure passage; and
a detector for detecting a leak of the fuel vapor from the evaporation system toward an outside thereof based on the pressure measured by the pressure sensor while the pump depressurizes the evaporation system, wherein
the detector determines that an adsorbed amount of the fuel is close to an upper limit of a canister adsorbing capacity and the fuel vapor is desorbed from the canister to the measure passage when the pressure measured by the pressure sensor is varied toward an atmospheric pressure.
2. A leak detecting apparatus according to claim 1, further comprising
a passage valve for openingclosing the measure passage, wherein
the detector controls the passage openingclosing valve in such a manner that the measure passage is closed when the discharge of the fuel vapor is detected.
3. A leak detecting apparatus according to claim 1, wherein
the detector stops the pump when the discharge of the fuel vapor is detected.
4. A fuel vapor treatment apparatus comprising:
an evaporation system in which a fuel vapor evaporated in a fuel tank flows, the evaporation system including a canister for adsorbing the fuel vapor in such a way that the fuel vapor can be desorbed;
a measure passage;
a pump connecting with the canister through the measure passage;
a pressure sensor for measuring a pressure in the measure passage; and
a detector for detecting a leak of the fuel vapor from the evaporation system toward an outside thereof based on the pressure measured by the pressure sensor while the pump depressurizes the evaporation system, wherein
the detector determines that an adsorbed amount of the fuel is close to an upper limit of a canister adsorbing capacity and the fuel vapor is desorbed from the canister to the measure passage when the pressure measured by the pressure sensor is varied toward an atmospheric pressure,
the evaporation system includes a purge passage for introducing the fuel vapor, which is desorbed from the canister, into an intake passage of an internal combustion engine, and a purge passage valve for openingclosing the purge passage, and
the detector performs the leak detecting process while the purge passage valve closes the purge passage.
5. A fuel vapor treatment apparatus according to claim 4, further comprising:
a restrictor passage communicating with the measure passage and having a restrictor therein;
an atmosphere passage opened to an atmosphere;
a passage switch for switching a passage communicating with the restrictor passage between the purge passage and the atmosphere passage;
a pressure sensor for measuring a pressure between the pump and the restrictor while the pump depressurizing the restrictor passage; and
a concentration calculator for calculating a concentration of the fuel vapor in the purge passage based on the pressure measured by the pressure sensor.
6. A fuel vapor treatment apparatus according to claim 5, wherein
the passage switch switches the passage communicating with the restrictor passage between the purge passage and the atmosphere passage at a position opposite to the measure passage across the restrictor.