JPS63223304A - Shaft sealing device for gas expansion turbine - Google Patents

Abstract

PURPOSE:To make it possible to completely seal gas in an engine with a simple construction by making respective pressures in an intermediate chamber and a bearing drainage chamber between plural labyrinth seals, higher than an exhaust pressure, and supplying lubricant with a pressure higher than that in the bearing drainage chamber to a bearing. CONSTITUTION:Gas is introduced into a gas chamber 4 from a gas suction port 8 to rotate a rotary shaft 2 supported on a casing 1 by means of a bearing 3. Thereat, gas leaking from the vicinity of a labyrinth seal 5 is introduced into an exhaust chamber 7 through an equalizing pipe 6. And, an intermediate chamber 11 between respective labyrinth seals 9, 10 is intercommunicated with a suitable part with a pressure higher than that in the exhaust chamber 7 through an intercommunicating pipe 12 having a decompression regulation valve 13. Meanwhile, a supply pipe 17 of lubricant for the bearing 3 supplies lubricant with a pressure higher than that in a bearing drainage chamber 19. Lubricant leaking to the bearing drainage chamber 19 and gas leaking to the bearing drainage chamber 19 from the intermediary chamber 11 are exhausted to a gas-liquid separator 15 through a drainage pipe 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shaft sealing device applied to a gas expansion turbine such as a hydrogen expansion turbine.

[Conventional technology]

In conventional gas expansion turbines, various gas seal devices are used at the portion where the rotating shaft passes through the casing. The apparatus shown in FIG. 2, which uses a labyrinth seal, and the apparatus shown in FIG. 3, which uses a liquid film, are mainly used in gas compressors.

A liquid film type shaft sealing device normally used for a gas compressor or an expander has two rings that have a small gap with the rotating shaft at the part where the rotating shaft 2 passes through the casing 1, as shown in Fig. 3. One is the atmosphere side ring 21 and the other is the gas side ring 4.

Shaft seal oil with adjusted pressure is supplied between the two rings from the shaft seal oil supply port n, and one of the shaft seal oils is supplied to the atmosphere side ring 21.
The other leaks through the gap between the gas side ring n and the shaft, and the other leaks through the gap between the gas side ring n and the shaft. The oil leaked to the atmosphere side is discharged from the atmosphere side discharge loss, and the oil leaked to the gas side is mixed with the gas leaked from inside the machine and discharged from the inside discharge port 5.

The gas mixed with the shaft seal oil is collected in a seal oil trap device, where the oil and gas are separated, and the gas passes through an orifice and is released into the atmosphere or burned inside a chimney or the like and released. be done.

[Problem that the invention seeks to solve]

In the device shown in Fig. 2 that uses a labyrinth seal,
Since the gas leaks into the atmosphere, there are problems such as a decrease in the amount of gas in the system.

Next, according to the device shown in FIG. 3, the shaft seal oil and the gas mixed with the shaft seal oil are collected together in the seal oil trap device.
Here, the oil and gas are separated and the gas is released into the atmosphere through an orifice or by combustion inside a chimney or the like.

In this case, the released gas is wasted, and the gas in the system decreases, resulting in poor economic efficiency.

The pressure of the shaft seal oil supplied to the shaft seal device requires pressure adjustment separately from that of the lubricating oil supplied to the bearing, and requires a double pressure adjustment device. Furthermore, since a bearing device and a liquid film shaft sealing device are each required, it becomes difficult to supply an expander with a complicated device and good economic efficiency.

[Means for solving problems]

Two labyrinth seals are arranged between the inside of the turbine and the bearing oil drain chamber, and the pressure in the intermediate chamber between the two labyrinth seals is made higher than the exhaust pressure.

The pressure inside the machine is equalized with the exhaust pressure of the expansion turbine, and the pressure in the bearing oil drain chamber is made higher than the exhaust pressure.

Supply high pressure lubricating oil to the bearing from the bearing oil drain chamber. A mixture of leaked gas and lubricating oil collects in the bearing oil drain chamber, but this is separated in the gas-liquid separation chamber and the gas is returned to the exhaust chamber of the expansion turbine.

[For production]

Since the pressure in the bearing oil drain chamber is higher than the exhaust pressure of the expansion turbine, the gas after the gas-liquid separation is automatically returned to the exhaust gas.

A portion of the lubricating oil supplied to the bearing leaks into the atmosphere and a portion leaks into the bearing oil drain chamber.

In addition to the bearing-specific functions, the same functions as the liquid film shaft sealing device occur in the bearing.

〔Example〕

In Fig. 1, 1 is a casing, 2 is a rotating shaft, 3 is a bearing, 4 is a gas chamber, 5 is a labyrinth seal, 6 is a pressure equalizing pipe,
7 is an exhaust chamber, 8 is a gas inlet, 9.10 is a labyrinth seal, 11 is an intermediate chamber, 12 is a communication pipe, 13 is a regulating valve, 1
4 is an oil drain pipe, 15 is a gas-liquid separator, 16 is a drain pipe, 1
7 is a supply pipe, 18 is a return pipe, and 19 is a bearing oil drain chamber.

In such a table device, high-pressure gas flows in from the gas inlet 8, expands from the gas chamber 4 through the nozzle, and then moves to the rotary shaft 2, which has a turbine disk constructed by a known method.
(to achieve high-speed rotation). The rotating shaft is supported by three bearings. The gas after the first stage leaks through the gap between the labyrinth seal 5 and the fin rotating shaft, but most of this gas is led to the exhaust chamber 7 through the pressure equalizing pipe 6. An intermediate chamber 11 between labyrinth seals 9 and 10 communicates with both the high and low pressure sides of the turbine via labyrinths 9.10. This intermediate chamber 11 is also connected via a communicating pipe 12 to a chamber of a suitable intermediate stage of the turbine, which has a higher pressure than the pressure in the exhaust chamber 7. Also, this communication pipe 12
A valve 13 is provided to reduce and adjust the high pressure inlet gas, and gas can be supplied even when the turbine is stopped.

A lubricating oil supply pipe 17 to the bearing 3 supplies oil adjusted to an appropriately higher pressure than the bearing oil drain chamber 19 from another lubricating oil supply device to the bearing 3. The lubricating oil acts to lubricate the bearings in each bearing, and also leaks to the bearing oil drain chamber 19 and the atmosphere. The lubricating oil leaked into the bearing oil drain chamber 19 is transferred to the intermediate chamber 1.
1 into the bearing oil drain chamber 19 and is discharged through the oil drain pipe 14 to the gas-liquid separator 15. The gas separated in the gas-liquid separator 15 passes through the drain pipe 18, returns to the exhaust port, and flows into the gas system. The separated lubricating oil collects in the r-len pipe 16 together with the lubricating oil leaked to the atmosphere by the bearing, and returns to the separately installed lubricating oil supply device.

With this configuration, the pressure in the intermediate chamber 11 is always maintained higher than the exhaust pressure, so that the pressure in the gas-liquid separator 15 and the bearing oil drain chamber 19 can be raised higher than the exhaust pressure. Therefore, the gas-liquid separator 1
The gas separated in step 5 can be automatically returned to the exhaust port.

If the supply pressure to the bearing 3 is sufficiently higher than that of the bearing oil drain chamber 19, the lubricating oil will always leak simultaneously to the atmosphere side and the bearing oil drain chamber side, and at the same time will act to lubricate the bearing surface. .

As a result of the above, the gas in the gas expansion turbine is not released to the outside of the system, and a complete sealing effect is achieved.At the same time, the bearing 3 supports the rotating shaft 2, and at the same time, the rotating shaft 2 penetrates the casing 1. It can serve as a shaft sealing device in the parts where it is used.

〔Effect of the invention〕

By simply supplying oil adjusted to a single pressure from the lubricating oil supply system, it is possible to completely seal off the gas inside the aircraft.

By using the shaft seal device as a bearing, it is possible to provide a gas expansion turbine with a simple structure and high reliability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of a shaft sealing device for a gas expansion turbine according to the present invention. FIGS. 2 and 3 are cross-sectional views showing examples of forces of a shaft sealing device according to the prior art. FIG. 3 is an example of a liquid film shaft sealing device.

Claims (1)

[Claims] A plurality of labyrinth seals are disposed at a portion where the turbine rotation shaft supported by the hydrolubrication bearing penetrates the casing and constitute an intermediate chamber having a pressure higher than the turbine exhaust port pressure, and the intermediate chamber and A communication pipe communicating with an intermediate stage of the turbine is provided, and a pipe line for supplying a reduced pressure and regulated gas from a gas inlet of the turbine is connected to the communication pipe,
A means for supplying lubricating oil for liquid film shaft sealing to the fluid-lubricated bearing, and a gas-liquid separation means for separating a mixture of leaked gas and lubricant waste oil discharged from the bearing from the intermediate chamber. A shaft sealing device for a gas expansion turbine, characterized in that: