JP2000186685A - Rotary multistage vacuum pump device dealing with high temperature gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately operate a vacuum pump device by dealing with high temperature gas without cooling it. SOLUTION: Mechanical seals 51, 52 are arranged on housing sides of bearings 351, 352 supporting shafts of a vacuum pump. An oil tank 40 is arranged outside the vacuum pump for storing lubricating oil. An oil pump is attached to the oil tank for circulating the lubricating oil. A suction port of the oil pump communicates with the oil tank, while a discharge port communicates with oil feed pipes 311, 312 communicating with mechanical seal support bodies of gear and driving sides. An oil return passage 43 is led to the oil tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary type multi-stage vacuum pump for handling high-temperature gas. INDUSTRIAL APPLICABILITY The present invention can be applied to a vacuum pump device that handles a gas having a very high suction gas temperature, for example, 150C to 250C.

[0002]

2. Description of the Related Art In general, when the suction gas of a vacuum pump is at a high temperature, a method of cooling the gas by cooling water from the outer periphery of the pump housing or the inside of the rotor, or a method of installing a gas cooler immediately before suction to cool the suction gas. , And other measures have been taken. In the cooling from the outer periphery of the housing, a high temperature in the housing is transferred by a shaft supporting the rotor, and the bearing is heated to a temperature higher than the usable temperature. Further, in the method of cooling the gas with cooling water from inside the rotor, water must be supplied to the rotor, which is a rotating body, and the structure is complicated, and it is difficult to obtain mechanical stability. In the method of cooling the suction gas by installing a gas cooler just before the suction port, when the temperature becomes lower than the deposition temperature determined by the pressure and temperature of the gas, the gas precipitates as a solid, and it is difficult to operate the vacuum pump. Was.

[0003] As an example of a conventionally used multi-stage vacuum pump for cooling a housing from the outer periphery, a first pump section,
A three-stage rotary vacuum pump having a second pump section and a third pump section is shown in FIG. 8 is a sectional view taken along line VIII-VIII of the pump shown in FIG. 7, and FIG. 9 is a sectional view of FIG.
It is IX-IX sectional drawing. The structure of this pump is as follows. In FIG. 7, the partition 1 is divided into a first pump section and a second pump section, and the partition 2 is divided into a second pump section and a third pump section. Numeral 4 penetrates each pump section and is supported by two bearing mechanisms 5 respectively, and is incorporated by a timing gear set 6 so as to rotate in opposite directions. A flow path for the cooling water 7 is provided on the outer periphery of the housing. The first shaft can penetrate to the outside and can be driven by an electric motor.

As shown in FIGS. 7 to 9, the operation of this pump device is as follows. In the first pump section, the suction gas G51 of the pump passes through the suction port 8 of the pump and passes through the suction port 9 of the first pump section. G51 is sucked into the rotor 10
The discharged gas G52 transferred based on the operations of A and 10B and cooled by the cooling water on the outer peripheral portion of the housing is guided to the next stage through the connection path 11. The above operation is repeated in each stage, and the air is exhausted from the pump outlet 12.

[0005]

With the above structure and operation, the gas transferred and compressed by the rotor in the housing is heated by the heat of compression. Although a part of the housing is cooled by the cooling water 7 on the outer periphery of the housing, the rotor is not cooled, so that a high temperature in the housing is transmitted by the shafts 3 and 4 supporting the rotor, and the temperature of the bearing exceeds the usable temperature. There was a problem of heating.

Further, as shown in FIG. 10, a mechanism such as a journal joint 13 and a rotor 10A,
In the method of cooling the gas by the cooling water 14 injected into the 10B and discharging the gas from the shaft ends 17 and 18 on the opposite side, the heat is not transferred by the hollow shafts 15 and 16 supporting the rotor, but is a rotating body. Water must be supplied to the rotor, the structure becomes complicated, and water leakage occurs, and it is difficult to obtain mechanical stability.

In a method in which a gas cooler is installed just before the suction port to cool the gas and introduce the gas into the suction port, when the temperature becomes lower than the deposition temperature determined by the pressure and temperature of the gas, the gas precipitates as a solid and the vacuum Operation of the pump was difficult.

A main object of the present invention is to provide a rotary type multi-stage vacuum pump device capable of safely handling a high-temperature gas without cooling it in view of the above-mentioned problems in the conventional type. It is in.

[0009]

According to the present invention, a rotary vacuum pump is formed by a plurality of pump sections.
A shaft of each pump section supported by a bearing, a rotor fixed to these shafts, a pair of gears at a shaft end for synchronously rotating the rotor, and an oil tank for storing lubricating oil are provided. The built-in housing has a suction port,
A discharge port is provided, and a connection path between the discharge port of each pump section and the suction port of the next-stage pump section is provided, and compressed gas is sucked into the next step through this connection path, and sequentially in each step. In a rotary type multistage vacuum pump to be compressed, a mechanical seal is provided on a housing side of four bearings supporting a shaft, and an oil tank for storing lubricating oil is provided outside the vacuum pump. An oil pump for circulating oil is mounted, the suction port of the oil pump is connected to the oil tank, and the discharge port is connected to an oil feed pipe communicating with two mechanical seal supports on the gear side and the drive side. Return oil pipe is provided to be led to the oil tank,
A rotary type multi-stage vacuum pump device is provided.

In general, the pressure in the housing is high vacuum in the first stage, and near the atmospheric pressure in the third stage. This means that the pressure in the gear-side oil tank and the pressure in the drive-side oil tank are different,
Even when the two oil tanks are communicated with each other, the oil flows in the lower pressure direction, so that the lubricating oil in the drive-side oil tank cannot flow into the gear-side oil tank. In the apparatus according to the present invention, a mechanical seal is provided on the housing side of the bearing, pressure is sealed, both oil tanks are communicated with the atmospheric pressure, the internal pressure is equalized, and a return oil pipe is provided to communicate the two oil tanks. Became possible. By equalizing the pressure in both oil tanks, a thrust load is not generated on the shaft, the shaft can be easily fixed, and the life of the bearing can be extended.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As one embodiment of the present invention, the operation of a three-stage rotary vacuum pump will be described with reference to FIGS. 2 is a sectional view taken along the line II-II of the pump shown in FIG. 1, and FIG. 3 is a view showing an oil tank, an oil pump, an oil cooler, an oil feed pipe, and a return oil pipe in the vacuum pump device of FIG. FIG. 4 shows the mechanical seal on the left side in FIG.
FIG. 2 is a view showing a mechanical seal on the right side in FIG. 1. FIG. 6 is a view showing a section taken along line VI-VI of FIG.

In the vacuum pump device shown in FIGS. 1, 2 and 3, a rotary vacuum pump is formed by a plurality of pump sections, and shafts of the respective pump sections supported by bearings are provided. Is provided at the shaft end, a pair of gears are provided at the shaft end for synchronously rotating the rotor, and a housing containing each pump section is provided with a suction port and a discharge port. There is a connection between the discharge port of the section and the suction port of the next pump section,
The gas to be compressed is sucked into the next stage through this connection path,
Each stage is sequentially compressed. In the first pump section, the suction gas G21 of the pump passes through the suction port 21 of the pump, is sucked as suction gas from the suction port 23 of the first pump section, is transferred based on the operation of the rotors 22A, 22B, and is discharged. It is guided from the discharge port 24 to the next stage through the connection path. The above operation is repeated at each stage.

In this vacuum pump device, a mechanical seal 5 is provided on the housing side of the four bearings supporting the shaft.
1 and 52, an oil tank 40 for storing a lubricating oil 41 is provided outside the vacuum pump, and an oil pump 42 for circulating the lubricating oil is attached to the oil tank.
5 is connected to the oil tank and the discharge port is connected to a cooler 46.
, An oil feed pipe 311 communicating with two mechanical seal supports 341 and 342 on the gear side and the drive side, respectively.
By providing the 312, a return oil pipe 43 is provided for sending lubricating oil to the mechanical seal support and leading from the inside of the gear-side oil tank and the drive-side oil tank to the external oil tank.

In the first pump section, the suction gas G21 of the pump passes through the suction port 21 of the pump, is sucked as suction gas from the suction port 23 of the first pump section, and is supplied to the rotor 22.
A, 22B are transferred based on the operation of the discharge gas G22.
Is guided from the discharge port 24 to the next stage through the connection path. The above operation is repeated at each stage.

FIGS. 4 and 5 show mechanical seals 51 and 5 respectively.
2 are shown. The lubricating oil introduced from the lower part of the vacuum pump is used for fixing rings 511, 4 of the four mechanical seals.
After reaching the 521 part, it flows so as to wrap the shaft, cools the shaft, lubricates and cools the fixed rings 511, 521 of the mechanical seal, the sealing surfaces of the rotating rings 512, 522 and the bearing, and drops from the bearing side to the oil tank. I do. On the other hand, excess lubricating oil overflows from the upper portion of the mechanical seal through the hole communicating with the oil tank. The gear-side oil tank 271 and the drive-side oil tank 2
By providing a return oil pipe 43 that guides the lubricating oil that has fallen into 72 to the external oil tank 40 and forms a circulating flow path,
Lubricating oil can be circulated.

In the vacuum pump device according to the embodiment of the present invention, the circulation of the lubricating oil lubricates and cools the mechanical seal and the bearing, sufficiently cools the shaft, and heats the bearing to a usable temperature or higher. There is no. Even if the gas in the housing is maintained at a high temperature, since the bearings and gears are protected from the high-temperature housing, it is not necessary to cool the suction gas, and it is possible to handle a gas that precipitates by cooling. Thereby, the vacuum pump operates properly.

[Brief description of the drawings]

FIG. 1 is a diagram showing a vacuum pump device according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a diagram showing an oil tank, an oil pump, an oil cooler, an oil feed pipe, and a return oil pipe in the vacuum pump device of FIG.

FIG. 4 is a view showing a mechanical seal on the left side in FIG. 1;

FIG. 5 is a view showing a mechanical seal on the right side in FIG. 1;

FIG. 6 is a view showing a VI-VI section in FIG. 1;

FIG. 7 is a diagram showing an example of a conventional vacuum pump device.

FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7;

FIG. 9 is a sectional view taken along line IX-IX in FIG. 7;

FIG. 10 is a diagram showing an example of a conventional vacuum pump device.

[Explanation of symbols]

 20A, B ... Shaft 21 ... Suction port 22A, B ... Rotor 23 ... First stage suction port 24 ... First stage discharge port 271 ... Gear side oil tank 281 ... Gear side lubricating oil 51, 52 ... Mechanical seal 311 and 312 ... Sending Oil pipe 272 ... Drive side oil tank 282 ... Drive side lubricating oil 341,342 ... Mechanical seal support 351,352 ... Bearing G21 ... Suction gas G22 ... Discharge gas 40 ... Oil tank 41 ... Lubricant oil 42 ... Oil pump 43 ... Return oil pipe 44 ... Discharge port of oil pump 45 ... Suction port of oil pump 46 ... Oil cooler 511,521 ... Fixed ring 512,522 ... Rotary ring

Claims (1)

[Claims] A rotary type vacuum pump is formed by a plurality of pump sections, and a pair of shafts of each pump section supported by bearings, rotors fixed to these shafts, and shaft ends for synchronously rotating the rotors. Gears and an oil tank for storing lubricating oil are provided, and a housing containing each pump section is provided with a suction port and a discharge port. The connection between the discharge port of each pump section and the suction port of the next pump section is provided. A road is established,
The gas to be compressed is sucked into the next stage through this connection path,
In a rotary type multi-stage vacuum pump that is sequentially compressed at each stage, a mechanical seal is provided on the housing side of four bearings that support the shaft, and an oil tank for storing lubricating oil is provided outside the vacuum pump. An oil pump for circulating lubricating oil is attached to the oil tank, and the suction port of the oil pump is connected to the oil tank, and the discharge port is connected to two mechanical seal supports on the gear side and the drive side, respectively. A rotary type multi-stage vacuum pump device, wherein a return oil pipe communicated with an oil feed pipe and led to an oil tank is provided.