JPS60136665A - Shaft seal apparatus - Google Patents

Abstract

PURPOSE:To prevent the leak of the dangerous fluid inside a machine from the seal part of a rotary engine shaft to a machine chamber by forming an air chamber between a seal on the atmospheric side and an intermediate seal and forming a mixing-machine chamber between the intermediate seal and a seal on the machine side. CONSTITUTION:Though a minute amount of the dangerous fluid 13 inside a machine case 20 is introduced into a mixed-gas chamber 12, passing through a seal 1, the pressure inside the mixed-gas chamber 12 is increased by the inflow of a portion of the compressed air, and the inflow of the above-described fluid 13 is suppressed. When the fluid seal 1 on the danger side or an intermediate seal 2 is broken, the pressure in the mixed-gas chamber 12 increases, and a pressure switch 10 detects said increase. When a seal 3 on the atmospheric side is broken or the compressed air is not supplied from a compressed-air pipe 4, the pressure in a compressed-air chamber 11 lowers, and a pressure switch 7 detects said lowering, and an alarm is generated properly.

Description

[Detailed description of the invention] To prevent hazardous fluid inside the mechanism from leaking into the machine room etc. from the shaft seal part, and to detect and issue an alarm if the seal is damaged before the fluid leaks to the outside. These measures have been taken to ensure safe operation.

In a shaft-equipped part such as a rotating shaft, a certain amount of gap is unavoidable in order to ensure proper rotation of the rotating shaft, and internal fluid leaks from such a gap. In the past, it was generally assumed that such fluid leaks were unavoidable;
Problems caused by such leakage are avoided by minimizing this leakage and ensuring appropriate dilution with the atmosphere and indoor ventilation, but this is not preferable in particular, and there is a possibility that it may cause harm to the human body or cause a fire. In cases where dangerous fluids are used, even a small amount of leakage can cause various inconveniences. Of course, under conditions such as modern air conditioning equipment, dilution with the atmosphere and indoor ventilation naturally lead to an increase in operating costs.

The present invention was devised after repeated studies in view of the above-mentioned circumstances, and includes a bearing 21 attached to the machine noodle 2o to support the rotating shaft 18, and a dangerous fluid 1 inside the machine casing 20.
3, the bearing portion 21 is provided with a hazardous fluid side seal 1, an intermediate seal 2, and an atmosphere side seal 3, and a compressed air chamber 11 is formed between the intermediate seal 2 and the atmosphere side seal 3. A compressed air pipe 4 for factory use is connected in a compressed air chamber 11 for detecting leakage when a seal is broken, and the compressed air pipe 4 is equipped with a secondary pressure regulating valve 5 and an orifice 6.
and a pressure switch 7, and between the hazardous fluid side seal 1 and the intermediate seal 2, a discharge pipe 8 is provided between the hazardous fluid side seal 1 and the intermediate seal 2 for leading out a mixed fluid of a trace amount of fluid such as gas and compressed air to the outside or to a non-hazardous location. It is installed in the mixture chamber 12, and the discharge pipe 8 is provided with an orifice 9 for adjusting the flow rate and a pressure switch 10.

That is, according to the present invention as described above, compressed air from the compressed air pipe 4 flows through the orifice 6 under normal operating conditions.
A small amount of air flows into the compressed air chamber 11 according to the amount determined by the above, and a small amount of air flows into the atmosphere through the atmosphere side seal 3, and the other portion flows through the intermediate seal 2 into the mixture chamber 1.
Enter 2. Also, a small amount of the hazardous fluid 13 inside the machine casing 20 passes through the seal 1 and enters the mixture chamber 12, but the mixture chamber 12 is pressurized to a certain extent by some of the compressed air flow as described above, and the fluid 13 will be suppressed. However, the mixture chamber 12
Only the flow rate determined by the orifice 9 of the mixed and diluted fluid is discharged to a non-hazardous area by the discharge pipe 8, and as a result, no hazardous fluid leaks into the room or the like.

By the way, if the dangerous fluid side seal 1 or the intermediate seal 2 is damaged under the above operating conditions, the mixture chamber 1
2 pressure increases, which can be detected by the pressure switch 10. In addition, when the atmospheric side seal 3 has a pressure loss or compressed air is not supplied from the compressed air pipe 4, the pressure in the compression air chamber 11 decreases, and this is detected by the pressure switch T.
．． It is amazing that detection by 10 can give an appropriate warning, and even if any seal is damaged, it is possible to accurately prevent dangerous fluid from leaking into the room or the like. Note that the pressure switch 7.10 described above may be configured to detect the flow velocity or the like as appropriate.

According to the present invention as explained above, dangerous fluid leakage from the shaft seal portion of this type of rotary engine can be effectively and accurately prevented, and even if the seal is broken, this can be properly detected and an alarm can be issued before the fluid leaks. This requires other measures to be taken, and since it uses a fluid such as factory compressed air that is easily available and does not provide frictional resistance to the rotating shaft, there is nothing that will particularly increase costs. This invention also has the effect of ensuring smooth rotational drive, and is a highly effective invention industrially.

[Brief explanation of the drawing]

The drawing shows an embodiment of the present invention, and is a sectional view of a shaft sealing device according to the present invention. However, in this drawing, 1 is the hazardous fluid side seal, and 2 is the hazardous fluid side seal.
1'j: intermediate seal, aii, atmosphere side seal, 4 is compression wall trachea, 5 is secondary pressure regulating valve, 6.9 is orifice, 7.
10 is a pressure switch, 8 is a discharge pipe, 11 is a compressed air chamber,
12 is a mixture chamber, 13 is a dangerous fluid, 18 is a rotating shaft, 20
21 indicates a machine casing, and 21 indicates a bearing portion. Patent Applicant: Nippon Kokan Co., Ltd. Inventor: Takashi Nishikawa Fumito Masu 1) Representative: Toshio Patent Attorney: Shirakawa -- (-I

Claims (1)

[Claims] An air chamber is formed between the first seal and the intermediate seal, and a mixture chamber is formed between the intermediate seal and the machine side seal, and a compressed air pipe is connected to the air chamber, and the mixture chamber is not dangerous. A shaft sealing device characterized by connecting a discharge pipe for discharging to a location.