JPH0514599U - Defoaming device for refueling system - Google Patents

Abstract

(57) [Abstract] [Purpose] In the oil supply system where the installation position of the main oil pump and the oil tank have a level difference, the main oil pump inlet side piping becomes a negative pressure state, so that minute bubbles in the oil are large. Prevent bubbles from growing into bubbles that enter the main oil pump and cause cavitation. [Structure] The outlet side pipe and the inlet side pipe of the main oil pump 1 are connected by a branch pipe 6, and a part of the pressure oil on the outlet side of the main oil pump 1 is blown out into the inlet side pipe at high speed to generate air bubbles 5. Crush,
A fine foam 9 that is dispersed in oil.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a defoaming device for a refueling system of a rotary machine, and is applied to a device for forcibly refueling a main bearing of a rotary machine such as a large axial fan, a large centrifugal fan, a large compressor, a turbine, and a blower.

[0002]

[Prior Art]

 Fig. 5 shows an example of a refueling system in a conventional rotary machine, for example, a large axial fan for a thermal power plant. In FIG. 5, 1 is a main oil pump directly connected to the shaft end of the axial fan driving electric motor 3, 3 is an oil tank, and 4 is an axial fan main bearing forcibly refueled by the main oil pump 1.

A large axial fan employs a sliding bearing that requires forced lubrication as the main bearing 4. As a part of the oil supply system, the main oil pump 1 is driven by an axial fan so that oil can be supplied even during a power failure. It is directly connected to the shaft end of the electric motor 2. On the other hand, although the oil supply system includes the oil tank 3, the return oil piping from the axial flow fan main bearing 4 needs to have an appropriate gradient, and the axial center level of the large fan is 3 to 4 m. It is inevitable that the oil tank 3 is installed at a low position of about 0 to 1 m above the floor because of the height of the oil tank.

As a result, a level difference (hydraulic head difference) of about 2 to 4 m is inevitably generated at the installation position between the main oil pump 1 and the oil tank 3. Due to this head difference, the hydraulic pressure equal to the atmospheric pressure in the oil tank 3 becomes a negative pressure (about -0.2 to -0.4 Kg / cm ² ) at the main oil pump inlet. Further, the total length of piping from the oil tank 3 to the main oil pump 1 is about 10 to 20 m, and the hydraulic pressure at the main oil pump inlet is further negative due to the added piping resistance during this period.

[0005]

As described above, the inlet side of the main oil pump 1 has a negative pressure because the suction pressure of the pump itself and the oil tank 3 are lower than the main oil pump 1. There is. Therefore, the air component contained in the lubricating oil in the oil tank 3 is a minute bubble in the oil tank 3, but while being sucked into the main oil pump 1, it gradually grows and bonds inside the pipe, As shown in FIG. 6, immediately before the main oil pump inlet, large bubbles 5 having a diameter of about 100 mm are formed.

When these bubbles 5 enter the main oil pump 1 as they are, a cavitation phenomenon due to air trapping occurs. At this time, problems such as abnormal noise, shortened life of the main oil pump, hydraulic hunting, and vibration of pipes are caused, which lowers the reliability of the equipment and system.

As a conventional countermeasure against such a problem, a secondary oil tank is theoretically installed at a position at the same level near the main oil pump, and a primary oil tank and a primary oil tank are installed in the oil supply system on the floor. It was considered to install a backup pump that supplies oil from the oil tank to the secondary oil tank, but there was a problem of cost due to the countermeasure work such as additional power supply equipment and secondary oil tank installation space. It was

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an oil supply system in which the above problems are eliminated.

[0009]

[Means for Solving the Problems]

 For the above object, according to the present invention, there is provided a main oil pump which is directly connected to a shaft end of an electric motor for driving a rotating machine and which is sucked with lubricating oil from an oil tank and forcibly supplied to the bearings of the driven machine and the electric motor. In the provided oil supply system for rotating machinery, a branch pipe is provided in the main oil pump outlet side pipe, and the other end of this branch pipe is connected to the main oil pump inlet side pipe to apply pressure oil to the pipe immediately before the main oil pump inlet side. A defoaming device for a refueling system is provided by introducing a part of the above.

[0010]

[Action]

 According to the above means, by introducing a part of the pressure oil discharged from the main oil pump into the main oil pump inlet side piping, large bubbles in the lubricating oil immediately before the main oil pump inlet will flow into the oil at high speed. It is crushed by the kinetic energy of the pressure oil that is blown out and becomes a foam that is dispersed in the oil.

[0011]

【Example】

 FIG. 1 shows an oil supply system provided with a defoaming device according to the present invention. 1, the same elements as those shown in FIG. 5 are designated by the same reference numerals.

A branch pipe 6 is provided between the outlet side pipe and the inlet side pipe of the main oil pump 1 to connect them. As shown in detail in FIG. 2, the connecting portion A of the branch pipe 6 with the main oil pump inlet side pipe has a short pipe 7 attached in the middle of the pipe and a large number of tips are inserted into the short pipe 7. It is constituted by the defoaming nozzle 8. The tip of the defoaming nozzle 8 is attached to the short pipe 7, preferably, as shown in FIG. 3, the pressure oil blowing direction into the short pipe is offset from the radial direction of the short pipe 7. The number of nozzles of the defoaming nozzle 8 is appropriately determined according to the diameter of the oil pipe.

During operation of the main oil pump 1, the oil in the outlet side pipe is constantly pressurized, and a part of this pressure oil is passed through the branch pipe 6 connected to the main oil pump inlet side pipe. Defoaming is supplied to the nozzle 8. This pressure oil is blown out at high speed from the defoaming nozzle 8 into the short pipe 6 in the negative pressure state. At this time, the bubbles 5 that have grown to a diameter of around 100 mm in the pipe are crushed by the kinetic energy of the pressure oil blown out at high speed, stirred and made into small bubbles 9 with a diameter of 10 mm or less and dispersed in the oil. Be done. Therefore, large bubbles are not sucked into the main oil pump 1, and the cavitation phenomenon due to air trapping does not occur.

FIG. 4 shows another embodiment of the defoaming device. The short pipe 7 provided in the middle of the main oil pump inlet side pipe has an inner diameter somewhat smaller than that of the pipe to which it is connected. A defoaming ejector 10 for introducing pressure oil through the branch pipe 6 is provided in the short pipe 7. The defoaming ejector 10 has a tip bent in the axial direction of the short pipe 7 inside the short pipe 7 and is opened to the main oil pump 1 side.

Therefore, while the main oil pump 1 is in operation, the pressure oil on the outlet side of the main oil pump 1 is blown out at high speed into the oil of the main oil pump inlet side pipe, which is negatively pressured from the defoaming ejector 10 through the branch pipe 6. .. The pressure oil blown out at a high speed crushes and stirs the grown bubbles 5 in the pipe with the kinetic energy of the fluid to disperse the bubbles 5 with a diameter of around 100 mm into small bubbles 9 of 10 mm or less in the oil. .. As a result, air is not trapped in the main oil pump 1.

[0016]

[Effect of the device]

 Advantageous Effects of Invention According to the present invention, the structure is relatively simple and the cost is low, ancillary equipment such as a power source is not required, and it has an advantage of always functioning while the main oil pump is operating. Moreover, it can be applied not only to new refueling equipment but also to existing refueling equipment at extremely low cost.

[Brief description of drawings]

FIG. 1 is a diagram of an oil supply system including a defoaming device according to the present invention, showing an example of application to a large axial fan.

FIG. 2 is an enlarged sectional view showing details of a defoaming nozzle.

3 is a cross-sectional view of the defoaming nozzle shown in FIG.

FIG. 4 is a detailed view showing a second embodiment of the defoaming device according to the present invention.

FIG. 5 is a diagram showing a general oil supply system of a rotary machine.

FIG. 6 is an explanatory view showing bubbles grown in a pipe.

[Explanation of symbols]

 1 Main oil pump 6 Branch pipe 7 Short pipe 8 Defoaming nozzle 9 Foam 10 Defoaming ejector

Claims (1)

[Scope of utility model registration request] 1. An oil supply system for a rotary machine, comprising a main oil pump which is directly connected to a shaft end on an anti-load side of an electric motor for driving the rotary machine and which sucks lubricating oil from an oil tank into the bearings of the driven machine and the electric motor to forcibly supply the lubricating oil. In, the main oil pump outlet side pipe is provided with a branch pipe, the other end of this branch pipe is connected to the main oil pump inlet side pipe, and a part of the pressure oil is introduced into the pipe immediately before the main oil pump inlet side. Defoaming device for refueling system.