JPH07103189A - Oil feeder of oil film seal - Google Patents

Abstract

PURPOSE:To provide an oil feeder of an oil film seal, capable of corresponding to a range from low pressure to high pressure operation in a simple system, dispensing with a differential pressure transmitter and a differential pressure control valve for differential pressure control, and promoting a reduction in cost. CONSTITUTION:In an oil feeder of an oil film seal, controlling oil feeding pressure in a compressor sealing part 2 with a liquid level in a seal head tank 7 set up at the downstream side of this sealing part 2, a pipeline 3 cable of bypassing the sealing part 2 is installed in a downstream side pipeline 4 being connected to the seal head tank 7 from the side of oil feed to the sealing part 2, while an orifice limiting a bypass flow rate to the bypass pipe 3 or a check valve 5 made up of drilling a valve element is attached thereto. With this constitution, an amount of sealing oil passing through the compressor sealing part 2 is adjustable, whereby this oil feeder is able to correspond over the wide range of operation conditions from low pressure to the high pressure application and simultaneously any pressure loss in the compressor sealing part 2 is thus reducible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil film seal oil supply device used in a shaft seal device of a compressor.

[0002]

2. Description of the Related Art Some gases handled by a gas compressor cannot be leaked to the outside.
In such a case, the oil film seal is adopted as the shaft sealing device of the compressor. The oil film seal collects the seal oil in the seal head tank installed at a position higher than the compressor shaft core, maintains the pressure slightly higher than the internal pressure of the compressor, and supplies the seal oil to the shaft seal part to make a coaxial seal. This is a system in which an oil film is formed on the inside of the machine and oil is flowed to the outside and inside of the machine to seal the gas inside the machine.

In a conventional oil film oil supply apparatus, a front throttle system in which a control valve 11 is installed upstream of a compressor seal portion 12 as shown in FIG. 2 and a backflow side as shown in FIG. There are two types of post-throttle system installed at the. First, in the case of the pre-throttle system shown in FIG. 2, the heat generated by friction and stirring of the oil film seal portion is carried away by the amount of seal oil flowing out to the atmosphere side through the gap between the atmosphere side float ring 13 and the shaft, and Limits temperature rise. Further, a compressor seal having a wide range of operating conditions from low pressure to high pressure needs to determine the clearance between the atmosphere-side float ring 13 and the shaft in consideration of low pressure operation, and therefore the seal is not operated under high pressure conditions. The amount of oil increases, and the oil pump capacity increases accordingly.

On the other hand, in the case of the rear diaphragm system shown in FIG.
Gap flow of atmosphere side float ring 13 and inside seal part 14
It can be said that this system is advantageous as a seal oil supply system for compressors having low to high pressure operating conditions because it is cooled from both the seal oil passing through. Conventionally, in both the front throttle system and the rear throttle system, the differential pressure between the gas side and the seal oil supply side is detected and returned to the oil tank through the differential pressure control valve 15. Further, the seal hydraulic pressure during normal operation is controlled by controlling the liquid level height H of the seal head tank 16. The differential pressure control valve 15 is for bypassing the seal oil supply so that the seal oil supply amount corresponds to the gas pressure in the compressor. In FIGS. 2 and 3, 17 is a pressure comparison device that compares the pressure of gas in the compressor with the pressure of oil in the seal oil supply pipe and outputs a signal, and 18 is a differential pressure control of the output signal of the pressure comparison device 17. Valve 1
5 is a signal line transmitted to

[0005]

The rear throttling system shown in FIG. 3, which has a good cooling effect as described above, has the following drawbacks. That is, since the entire amount of the seal oil discharged from the seal oil pump passes through the small-diameter hole 12a formed in the casing of the compressor seal portion 12, the pressure loss in this portion becomes excessive and the difference with the internal gas is increased. The pressure increases even though the liquid level height of the head tank 16 is controlled. As a result, the amount of sour oil leaking to the inside of the machine (which becomes waste oil due to dirty oil that comes into contact with gas) increases, and there is a drawback that the running cost increases due to the large consumption of seal oil. The present invention has been proposed to solve the above conventional problems.

[0006]

For this reason, the present invention provides an oil film seal oil supply device for controlling the oil supply pressure of a compressor seal part by the liquid level of a seal head tank installed on the downstream side of the seal part. In addition, a pipe that can bypass the seal part is provided in the downstream pipe connected to the seal head tank from the oil supply side to the seal part, and a hole is formed in the orifice or valve body that limits the bypass flow rate in the bypass pipe. The check valve is attached, and this is used as a means for solving the problem.

[0007]

In the present invention, since the bypass pipe that bypasses the compressor seal portion is provided in the post-throttle oil supply system, the amount of seal oil that passes through the compressor seal portion can be adjusted, and low pressure to high speed operation can be achieved. Since the pressure loss at the compressor seal can be reduced over a wide range of conditions, the pressure difference in the head tank can be maintained at a specified value, and the sour oil amount is not increased. Further, it is not necessary to control the adjusting pressure by the pressure difference between the seal oil pressure and the gas inside the machine, and it is possible to eliminate the operation of the system and the errors associated therewith.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the drawings. FIG. 1 is a system diagram of a rear throttle oil supply system showing an embodiment of the present invention. In the post-throttle lubrication system shown in FIG.
Bypassing the compressor seal portion 2 to the seal oil supply pipe 1, a bypass pipe 3 communicating with the seal oil return pipe 4 is provided. The bypass pipe 3 is provided with a check valve 5 having a hole in the orifice or the check valve body. As a result, the amount of oil passing through the compressor seal portion 2 can be adjusted, wide range operation from low pressure to high pressure can be performed, the pressure loss of the compressor seal portion 2 can be reduced, and the head tank differential pressure can be set to a specified value. Can be held. It is also possible to omit the differential pressure control between the seal oil pressure and the in-machine gas pressure.

A seal head tank 7 is connected to the compressor seal portion 2 by a gas reference line 6 so that the gas pressure in the compressor and the pressure in the seal head tank are kept the same. ing. Further, since the seal head tank 7 is connected to the compressor seal portion 2 through the gas reference line 6, the pressure of the oil supplied to the seal portion 2 depends on the gas pressure inside the compressor and the liquid level of the seal head tank 7. It is the sum of the pressure corresponding to the height and the pressure loss when the seal oil flows through the seal oil return pipe 4. 8 is a level transmitter that measures the height of the liquid level in the seal head tank 7 and outputs the measured value (signal). 9 is a signal line that transmits the signal from the level transmitter 8 to the level control valve 10. A level controller (not shown) is installed on the signal line 9. Further, the level control valve 10 is the control valve 11 shown in FIGS.
Similarly to the above, the liquid level of the seal head tank 7 is controlled so as to be maintained at a constant value.

[0010]

As described in detail above, according to the oil supply device in the post-throttle of the present invention, it is possible to cope with low pressure to high pressure operation with a simple system, and a differential pressure transmitter or a differential pressure control valve for differential pressure control. Is unnecessary, the cost can be reduced, and the operation can be simplified and the operation error can be reduced. In addition, it reduces pressure loss when passing through the small-diameter hole in the seal part, and can maintain the differential pressure of the head tank at a specified value, so it has many excellent effects such as not increasing the sour oil amount. The effect of improving reliability is extremely large.

[Brief description of drawings]

FIG. 1 is a system diagram of a rear throttle oil supply device according to an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional front throttle oil supply device.

FIG. 3 is a system diagram of a conventional rear throttle oil supply device.

[Explanation of symbols]

 1 seal oil supply pipe 2 compressor seal part 3 bypass pipe 4 pipe returning to seal oil tank 5 check valve 6 gas reference line 7 seal head tank 8 level transmitter 9 signal line 10 level control valve

Claims (1)

[Claims] 1. An oil film seal oil supply device for controlling the oil supply pressure of a compressor seal part by the liquid level of a seal head tank installed on the downstream side of the seal part, from the oil supply side to the seal part. Provide a pipe that can bypass the seal part in the downstream pipe connected to the seal head tank, and install a check valve with a hole in the orifice or valve body that limits the bypass flow rate in the bypass pipe. The characteristic oil film seal oil supply device.