JPS5811973Y2 - Shaft sealing device for gas compressor - Google Patents

Description

[Detailed Description of the Invention] Fig. 1 is a flow sheet of a gas compressor equipped with a conventional shaft sealing device, and Fig. 2 is an enlarged sectional view of the shaft sealing portion of the gas compressor.

In the figure, reference numeral 1 denotes a rotary gas compressor, which is equipped with a pressure equalizing gas chamber 3, a shaft sealing liquid supply chamber 4, and an atmospheric chamber 5, which are successively adjacent to each other toward the outer end of the rotor 2. Prevents leakage.

That is, a floating ring seal 6.7 as shown in FIG. 2 is inserted into the shaft sealing liquid supply chamber 4, and a floating ring seal 6.7 as shown in FIG. Shaft sealing liquid under pressure is applied from the head tank 8.

Shaft sealing liquid controlled by a liquid level control device 10 is supplied to the head tank 8 from a shaft sealing liquid tank 9 located at a lower position than the gas compressor 1 by a shaft sealing liquid supply pump 11 .

The top of the head tank 8 and the pressure equalizing gas chamber 3 are connected by a pipe 12, and the shaft sealing liquid is always kept at a pressure higher than the pressure in the pressure equalizing gas chamber 3 by the height of the head tank 8. The shaft sealing liquid is supplied to the shaft sealing liquid supply chamber 4 via the supply pipe line 13.

The supplied shaft sealing liquid passes through the gaps 14 and 15 between the two rotor shafts and the floating ring seals 6 and 7 and enters the atmospheric chamber 5.
The shaft sealing liquid that has been divided into the pressure equalizing gas chamber 3 and flowing into the atmospheric chamber 5 is returned to the shaft sealing liquid tank 9 through the drain pipe 16.

However, since the shaft sealing liquid that has flowed into the pressure equalizing gas chamber 3 may be contaminated by the working fluid of the gas compressor 1, it cannot be returned to the shaft sealing liquid tank 9, and is drained through the drain oil pipe 17. The liquid is discarded into the liquid tank 18.

Since the shaft sealing device described above uses expensive oil as shaft sealing fluid, if the amount of shaft sealing fluid that is discarded into the drain tank 18 is too large, it will have a large impact on the running cost of the gas compressor. Therefore, we try to minimize leakage as much as possible.

However, if the amount of the shaft sealing liquid passing through the gap is reduced, the temperature rise of the shaft sealing liquid in this area increases accordingly, and carbide is generated and adheres to the inner surface of the floating seal 7, narrowing the gap 15.

If this happens, the amount of shaft sealing liquid passing through the gap 15 will become smaller and smaller, and the vicious cycle will repeat, so there is a risk that the floating seal 7 will seize up.

Therefore, in order to eliminate this drawback, the present applicant previously proposed a shaft sealing device for a gas compressor in Japanese Patent Application No. 50-3422.
As shown in the figure ← proposed.

In FIG. 3, reference numeral 19 denotes a gas compressor, which includes a pressure equalizing gas chamber 20, a shaft sealing liquid supply chamber 21, and so on, which are successively adjacent to each other toward the outer end of the rotor (not shown). An atmospheric chamber 22 is provided, and the pressure relationship between these chambers prevents leakage of the working fluid.

In addition, a screw pump 25 is provided with floating rings 23 and 24 and has a screw groove between the rings 23 and 24.
, and the same screw pump 25 and floating ring 24 are provided.
A pressure chamber 26 is formed between the shaft sealing liquid supply chamber 21 and the atmospheric chamber 2.
A floating ring 23 is disposed between the two, and shaft sealing liquid under pressure acts on the shaft sealing liquid supply chamber 21 from a head tank 27 provided at a position higher than this level via a pipe line 28. It has become.

Further, the pressure chamber 26 and the pipe line 28 are connected through a pipe line 29, and a cooler 30 and a valve 31 are provided on the pipe line 29.

In the figure, 32 is a liquid level control device, 33 is a shaft sealing liquid supply pump, and 34.35 is a rotor shaft 36 and floating ring 2.
A gap 37 between the head tank 27 and the pressure equalizing gas chamber 20 is a pipe line connecting the top of the head tank 27 and the pressure equalizing gas chamber 20.

Next, to explain the operation of the device shown in FIG. 3, first, the pumping action of the screw pump 25 is directed from the floating ring 23 to the floating ring 24.

During normal operation, if the valve 31 is left open, the pressures in the shaft sealing liquid supply chamber 21 and the pressure chamber 26 will be approximately equal, and the pressure in the pressure equalizing gas chamber 20 will be equalized in the same manner as shown in FIG. The working fluid is sealed.

Then, when it is predicted that carbide or the like is attached to the floating ring 24, the valve 31 is closed.

The opening/closing operation of the valve 31 can be performed either automatically or manually, and may also be opened/closed periodically at intervals set by a timer.

However, the screw pump 25 with the structure shown in FIG.
is fixed to the casing 19, so the gap C with the shaft 36 is naturally regulated by the amount of axial runout of the shaft 36, etc.

Incidentally, it is known that the performance of the screw pump 25 improves as the gap C becomes smaller, but the method shown in FIG. 3 naturally has its limits in order to make the gap C as small as possible.

The present invention was proposed to solve the above-mentioned conventional drawbacks, and includes an in-flight gas chamber, a shaft sealing liquid supply chamber, and an atmospheric chamber adjacent to each other in the axial direction of the rotor shaft of a gas compressor, and a coaxial sealing liquid supply chamber and an atmosphere chamber. In a shaft seal device in which a floating ring is provided between a supply chamber and an atmospheric chamber with a gap between the rotor shaft and the rotor shaft, a first floating part is provided inside the machine, a second floating part is provided in the shaft seal liquid supply chamber, and these parts are provided. A screw pump section is disposed between each floating section, and each of these sections is provided with gaps CI, C2, and C3 from the rotor shaft, respectively, and these are made into an integral member, and the first floating section and the screw pump section are A pressure chamber is formed between the first floating part and the screw pump part by being elastically supported by the casing via the seal member, and the pressure chamber and the shaft sealing liquid supply chamber are connected to the gap C3 between the screw pump part and the rotor shaft. It is an object of the present invention to provide a shaft sealing device for a gas compressor, which is characterized in that the shaft sealing device is in communication with the shaft sealing device via the shaft sealing device.

The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 4 is a sectional view of the main parts of a shaft sealing device showing an embodiment of the present invention.

In the figure, 38 is a rotor shaft of a gas compressor, and an in-machine gas chamber 39, a shaft sealing liquid supply chamber 40, and an atmospheric chamber 41 are provided adjacent to the rotor shaft 38 in the axial direction. A floating ring 42 is provided between the rotor shaft 38 and the atmospheric chamber 41 with a gap therebetween.

Shaft sealing liquid under pressure acts on the shaft sealing liquid supply chamber 40 via a pipe line 43 from a head tank (not shown) provided at a position higher than this level.

44 is a first floating part provided inside the machine, 45
46 is a screw pump part arranged between each of these floating parts 44 and 45, and each of these parts is connected to the rotor shaft 38.
and gaps CI, C2, and C3, and these are formed into an integral member 47.

The first floating part 44 and the screw pump part 46 are elastically supported by the casing 50 via O-rings 48 and 49.
A pressure chamber 51 is formed therebetween, and the shaft sealing liquid in the shaft sealing liquid supply chamber 40 is sent to the pressure chamber 51 through a hole 52, a gap C3, and a hole 53, and the pressure chamber 51 is connected to a pipe line 54. It is connected to the pipe line 43 via a cooler (not shown) or the like.

Next, the operation will be described. The integral member 47 is in a floating state without contacting the rotor shaft 38 due to the oil film force generated in the first floating part 44 and the second floating part 45.

Note that the O-rings 48 and 49 are provided with a tightness that does not restrict the floating operation of the integral member 47.

Since the integral member is floating as described above, the first
If the gap C1 between the floating part and the rotor shaft and the gap C2 between the second floating part and the rotor shaft are made approximately equal, the gap C3 between the screw pump part and the rotor shaft should be set to a value slightly larger than the gap CLC2. This makes it possible to reduce the gap between the conventional screw pump part and the bellows rotor shaft, resulting in a screw pump effect with better performance than the conventional screw pump part.

[Brief explanation of the drawing]

Fig. 1 is a flow sheet of a gas compressor equipped with a conventional shaft sealing device, Fig. 2 is an enlarged sectional view of the shaft sealing part of the same gas compressor, and Fig. 3 is a sectional view of a conventionally proposed shaft sealing device. , FIG. 4 is a sectional view of essential parts of a shaft sealing device showing an embodiment of the present invention. Explanation of main parts of the diagram 38... Rotor shaft, 39
...In-flight gas chamber, 40...Shaft sealing liquid supply chamber, 41...Atmospheric chamber, 42...Floating ring, 44... First floating part, 45... Second floating part, 46...
...Screw pump part, 47...Integrated member, 4
8.49...O-ring (sealing member), 50.
...Casing, 51...Pressure chamber, CI
, C2, C3... gap.

Claims (1)

[Scope of utility model registration request] The in-flight gas chamber is located axially adjacent to the rotor shaft of the gas compressor.
In a shaft sealing device including a shaft sealing liquid supply chamber and an atmospheric chamber, and a floating ring having a gap with the rotor shaft between the coaxial sealing liquid supply chamber and the atmospheric chamber, a first floating part is provided inside the machine. , a 270-th ring part is provided in the shaft sealing fluid supply chamber, a screw pump part is arranged between each of these floating parts, and these parts are connected to the rotor shaft and the gap CI, respectively.
The first floating part and the screw pump part are elastically supported by the casing through a sealing member, and the first floating part and the screw pump part are provided with C2 and C3, and are made into an integral member. forming a pressure chamber,
A shaft sealing device for a gas compressor, characterized in that the pressure chamber and the shaft sealing liquid supply chamber communicate with each other via a gap C3 between a screw pump section and a rotor shaft.