Design of High Pressure Oil Jacking Device for Hydro Generator

The high-pressure oil jacking device in the thrust bearing lubrication system of the hydro-generator is a device that forms an oil film to lubricate the bearing. Its function is to spray high-pressure oil on the thrust bearing surface when the generator set starts and stops. Today, Starlight Power Equipment will take you to understand the defects of the design principle of the high-pressure oil jacking device of the hydro-generator and the status after improvement.

In the case of AC power, when the system needs to work, first open the stop valve, close the stop valve, the two-position three-way solenoid valve is turned on, and the two-position three-way solenoid valve is in a power-off state, start the AC motor to drive the gear pump the purpose of spraying high-pressure oil can be realized by running it (at the same time, the relief valve should be at the pre-set pressure value). The three-way solenoid valve is turned on when power is turned on, and the two-position three-way solenoid valve is in a power-off state. Start the DC motor to drive the gear pump to run, and the purpose of spraying high-pressure oil can be achieved.

According to the above principle, according to the actual use situation, it is found that there are many defects:

(1) During the actual use of a power station, several serious accidents of gear pump burst occurred during the installation and commissioning stage.

(2) After the electric contact pressure gauge is used for a period of time, some contacts are oxidized, resulting in the failure of the electric contact pressure gauge. And when the pressure is unstable or there is a large vibration source, the electric contact pressure gauge will fail to act, so that the signal cannot be sent.

(3) The normally closed two-position three-way solenoid valve has many misunderstandings during the commissioning stage, and it is difficult to judge whether the solenoid valve is open or closed, thus affecting the operation of the oil pump.

By analyzing the problems reflected in the use process one by one, it is found that:

On the one hand, the operators of the power station themselves do not have enough grasp of the operating procedures of the high-pressure oil jacking device system itself. On the other hand, it also reflects that there are some loopholes in the original design principle itself. Analyzing the schematic diagram of the system, it was found that when the AC motor was working, if the worker misoperated and did not open the stop valve, the relief valve could not play a role in safety protection, which caused the gear pump to continue to be pressed and eventually burst.

In view of the shortcomings of the original state of the high-pressure jacking device, we have improved the high-pressure oil jacking device. In response to the problems that have occurred, improvements are made point by point:

(1) Change the two-position three-way solenoid valve of the AC motor circuit from the normally closed type to the normally open type, so as to reduce the possibility of system failure caused by the suction of the oil pump because the solenoid valve is not switched to the passage (usually Use only the AC motor circuit, the DC motor circuit is the backup circuit).

(2) Adjust the position of the relief valve and increase the number of relief valves (here the relief valve is used as a safety valve). This fundamentally solves the problem that the oil pump is continuously pressed due to the misoperation of the shut-off valve, and the overflow valve cannot overflow and eventually causes a serious accident. That is to avoid serious consequences caused by misuse.

(3) Cancel the electric contact pressure gauge and add two pressure relays to control a high point pressure and a low point pressure respectively. Thus, the reliability of the system pressure control is improved.

(4) According to the actual use situation (the operating pressure reaches 30MPa), consider the system stability and the safety of the debugging process, and replace the original gear pump with an axial piston pump.

The high-pressure oil jacking device of the hydro-generator is aimed at the use defects reported by previous customers. After the R&D personnel improved its design principle, the unit was commissioned and delivered to the customer for installation and use. The customer reported that the unit equipment was running well, and the previous problems and defects were basically solved.

Starlight Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to sales@dieselgeneratortech.com we will pay highly attention on your question.