JPH04347395A - Oil film sealer for compressor - Google Patents

Abstract

PURPOSE:To prevent a drain of sour oil so far used as seal oil from increasing in quantity even in the case where a compressor is operated at a low speed revolution. CONSTITUTION:In this device, a seal oil control valve 8 being installed in a seal oil feeding route is controlled by an external reset type level controller 9 through a level indicating signal out of a level transmitter 11 installed in a seal head tank 4 and a revolving index indicating signal of a revolution transmitter 10 installed in a steam turbine 2 driving a compressor 1, and according this device, a seal oil level in the seal head tank 4 is lowered to some extent at the time of rotational frequency being low, and thereby any possible increase in the drain of sour oil is made so as to be checked.

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 device for a compressor, which supplies seal oil from a seal head tank to a shaft seal portion of a compressor.

0002

[Prior Art] Centrifugal compressors, screw compressors, etc. that handle petroleum gas and harmful gases do not allow gas inside the compressor to leak out of the machine, or conversely, allow outside air to enter the compressor. be. An oil film seal device is employed as a shaft seal device for such a compressor.

[0003] The oil film seal device stores seal oil in a seal head tank and pumps this seal oil to a pressure slightly higher than the internal pressure of the compressor (0.3 to 0.4 kg).
f/cm2) and supply it to the shaft sealing part of the compressor,
The supplied seal oil is allowed to flow out to the outside and inside of the compressor, thereby forming an oil film on the shaft seal.

[0004] Since the oil spilled to the outside of the machine does not come into contact with the gas inside the machine, it is collected in a seal oil tank and recirculated to be used as seal oil. However, as the oil that spills into the inside of the machine comes into contact with the cabin gas, the gas dissolves into the oil and becomes dirty. Therefore, it can be collected as sour drain in a sour drain tank, recycled, and then reused. It will be disposed of as is.

[0005]

[Problem to be Solved by the Invention] As described above, an excessive amount of sour drain directly affects the operating cost of the compressor. There was a desire to reduce as much as possible.

The amount of sour drain is influenced by the clearance of the shaft seal, the seal differential pressure, the viscosity of the seal oil, the rotation speed of the compressor, etc. Among these factors, the influence of the rotation speed is most noticeable. It is known that the amount of sour drain increases significantly as the rotation speed decreases. Therefore, in a compressor driven by a steam turbine or the like, there is a problem in that the amount of sour drain increases significantly when the operating condition of the compressor is set to a low rotational speed due to process requirements etc. . The present invention has been made to solve such problems and to meet the desire to reduce the amount of sour drain as much as possible.

[0007]

[Means for Solving the Problems] The present invention allows seal oil supplied from a seal head tank to the shaft seal of a compressor to flow out to the outside and inside of the compressor. In an oil film sealing device for a compressor that forms an oil film, a seal oil regulating valve disposed in a seal oil supply path is controlled by a liquid level indication signal from a liquid level transmitter provided in the seal head tank and the compressor. It is controlled by a rotation speed instruction signal from a rotation speed transmitter provided on a rotating device that drives the machine.

[0008]

[Operation] According to the above means, when the compressor is driven at a low rotation speed, the liquid level in the seal head tank is lowered by the rotation speed instruction signal from the rotation speed transmitter provided in the rotating equipment. By controlling the seal oil control valve, the seal differential pressure can be set low and the compressor can be operated with a reduced amount of sour drain.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the oil film sealing device for a compressor according to the present invention will be described in detail below with reference to FIGS. 1 and 2.

FIG. 1 is a system diagram showing an embodiment of an oil film sealing device for a compressor according to the present invention. Compressor 1 is mechanically coupled to and driven by steam turbine 2 . Seal oil is supplied to the shaft seal portion 3 of the compressor 1 from a seal head tank 4. The seal oil supplied to the shaft seal part 3 of the compressor 1 flows out to the outside and inside of the machine and forms an oil film on the shaft seal part 3, but the seal oil that flows out to the outside of the machine flows into the seal oil tank 5. It can be accumulated. On the other hand, the seal oil that has leaked into the inside of the machine is stored in the sour drain tank 6 as sour drain oil.

A seal oil pump 7 is installed in the seal oil tank 5.
are connected to each other, and the seal oil stored in the seal oil tank 5 is recirculated by the seal oil pump 7 to the seal head tank 4 and the shaft seal portion 3 of the compressor 1 through the seal oil control valve 8. There is. And this seal oil control valve 8
is equipped with an external reset type liquid level controller 9. This external reset type liquid level controller 9 is controlled by signals from a rotational speed transmitter 10 provided in the steam turbine 2 and a liquid level transmitter 11 provided in the seal head tank 4. That is, the rotation speed transmitter 10 detects the rotation speed of the steam turbine 2 and sends it out as a rotation speed instruction signal, and the liquid level transmitter 11 detects the oil level of the seal oil in the seal head tank 4. This signal is sent out as a liquid level indication signal. In addition, 12 is a balance pipe which connects the compressor 1 and the seal head tank 4, and is for balancing the pressure in the compressor 1 and the pressure in the seal head tank 4.

The oil film sealing device of the present invention configured as described above allows the liquid level controller 9 to be connected to the liquid from the liquid level transmitter 11 when the compressor 4 is operated at the normal design rotation speed. By operating with the level instruction signal, the seal oil regulating valve 8 is controlled so as to maintain the liquid level of the seal oil in the seal head tank 4 at a level such that the seal differential pressure becomes a predetermined differential pressure. On the other hand, due to requests from the process side, etc.
When the compressor 4 is operated at low rotation speed, the level of seal oil in the seal head tank 4 is controlled by operating the liquid level controller 9 using the rotation speed instruction signal from the rotation speed transmitter 10. The seal oil control valve 8 is designed to prevent an increase in the amount of sour drain by lowering the liquid level and lowering the seal differential pressure.
control.

Thereafter, when the operating conditions return to normal, the liquid level controller 9 is switched to be operated by the liquid level indication signal from the liquid level transmitter 11, and the liquid level of the seal oil in the seal head tank 4 is adjusted. control.

FIG. 2 is a characteristic diagram shown to explain the characteristics of the oil film seal device of the present invention.
A operates the liquid level controller 9 only by the liquid level indication signal,
This shows a case where the level of seal oil in the seal head tank 4 is controlled. In this case, when the compressor 1 is operating at the design speed, the sour drain amount is the lowest,
A constant quadratic curve is drawn such that the amount of sour drain increases as the rotation speed decreases.

In the figure, B represents the case where the liquid level of the seal oil in the seal head tank 4 is controlled by operating the liquid level controller 9 using the rotational speed instruction signal from the rotational speed transmitter 10. The amount of sour drain, which was the lowest when the compressor 1 was operated at the design rotation speed, increases as the rotation speed decreases, but the rate of increase is low, and this is due to the seal oil in the seal head tank 4. This is done by lowering the liquid level and lowering the seal differential pressure.

[0016]

[Effects of the Invention] As detailed above, according to the present invention, even if the operating conditions of the compressor 4 change and the compressor 4 is operated at a rotation speed lower than the design rotation speed, the amount of sour drain can be significantly increased. This reduces the consumption of seal oil. Therefore, operating costs can also be reduced.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of an oil film seal device for a compressor according to the present invention.

FIG. 2 is a characteristic diagram shown for explaining the characteristics of the device of the present invention.

[Explanation of symbols]

1 Compressor 2 Steam turbine 3 Shaft seal part 4 Seal head tank 8 Seal oil control valve 9 Liquid level controller 10 Rotation speed transmitter 11 Liquid level transmitter

Claims (1)

[Claims] [Claim 1] Compressor oil that forms an oil film on the shaft seal portion of the compressor by causing the seal oil supplied from the seal head tank to the shaft seal portion of the compressor to flow out to the outside and inside of the compressor. In the film seal device, a seal oil control valve disposed in a seal oil supply path is connected to a liquid level instruction signal from a liquid level transmitter provided in the seal head tank and is provided in a rotating device that drives the compressor. An oil film seal device for a compressor that is controlled by a rotation speed instruction signal from a rotation speed transmitter.