JPH06193580A - Rotary vane pump - Google Patents

Abstract

PURPOSE:To provide a rotary vane pump to prevent leakage of gas, passing through a housing, through a gap in the periphery of the rotory shaft, inserted in the shaft hole of a wall on the housing wall, to the outside even when the degree of a vacuum in the housing is low. CONSTITUTION:An airtight chamber 60 communicated with gaps 30a and 30b, formed between a housing side wall and the periphery of the rotary shaft 10 of a rotor inserted in a shaft hole 22 opened to a housing side wall 20a, and the outside of the housing 20 is formed to the outside of the housing side wall 20a in a manner to cover the gaps 30a and 30b on the periphery of the rotary shaft 10 of the rotor. The airtight chamber 60 communicated with the vacuum system on the gas suction port side of the rotary vane pump through an orifice 80.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary vane pump used as a transfer pump for transferring gas such as toxic gas.

[0002]

2. Description of the Related Art As shown in FIGS. 5 and 6, a rotor 12 having a plurality of vanes (not shown) slidably inserted therein is eccentrically supported in a housing 20 and is rotatably supported. Rotary vane pumps are well known.

According to this rotary vane pump, by rotating the rotor 12 in the housing 20, gas is sucked into the housing 20 from a gas suction port (not shown) provided in the housing 20, and the gas is sucked into the housing 20. The compressed gas can be discharged to the outside of the housing 20 from a gas discharge port (not shown) provided in the housing 20.

In this rotary vane pump, the rotary shaft 1 of the rotor is inserted in the shaft hole 22 formed in the side wall 20a of the housing.
0 is inserted through the gaps 30a and 30b. The end of the rotary shaft 10 of the rotor is attached to the housing side wall 20a.
It is rotatably supported via a bearing 42 on a bearing portion 40 provided outside. The bearing portion 40 is fixed to the outside of the housing side wall 20a through ribs 50 that are radially provided upright on the outside of the housing side wall 20a around the shaft hole 22.

In this rotary vane pump, as shown by the arrow in FIG. 6, when the rotor 12 is rotated clockwise together with the rotary shaft 10, the rotor 12 inserted into the shaft hole 22 is located above the rotary shaft 10. Gas such as outside air outside the housing 20 is sucked into the housing 20 through the gap 30a located on the side of the gas suction port (not shown) provided in the housing 20 corresponding to the gap 30a. Along with that, the shaft hole 22
The lower clearance 30b around the rotary shaft 10 of the rotor inserted in
Through the gap 30b located on the gas discharge port (not shown) side of the housing 20
The gas compressed from the inside is discharged to the outside of the housing 20.

In this rotary vane pump, when the vacuum degree inside the housing 20 is lowered by adjusting a vacuum regulator (not shown) provided on the gas suction port side, the housing is passed through the gap 30a on the gas suction port side. The suction amount of the gas sucked into the inside 20 is smaller than the discharge amount of the gas discharged from the inside of the housing 20 to the outside through the gap 30b on the gas discharge port side. On the contrary, when the vacuum inside the housing 20 is increased by adjusting the vacuum regulator (not shown) provided on the gas inlet side, the gap 30a on the gas inlet side is formed.
The suction amount of the gas sucked into the housing 20 through the housing 20 passes through the gap 30b on the gas discharge port side.
Compared with the amount of gas discharged from the inside to the outside,
Will increase.

As a result, when the degree of vacuum in the housing 20 is lowered, the amount of gas sucked into the housing 20 through the gap 30a on the gas inlet side is larger than the amount of gas sucked into the housing 20 through the gap 30b on the gas outlet side. Since the amount of gas discharged to the outside is superior, the gap 30
Gas is discharged from the inside of the housing 20 through a and 30b. Conversely, when the degree of vacuum in the housing 20 is increased, the housing 2 is passed through the gap 30a on the gas suction port side.
The discharge amount of the gas discharged to the outside of the housing 20 through the gap 30b on the gas discharge port side is inferior to the suction amount of the gas sucked into the gap 0.
Gas is sucked into the inside of the housing 20 from the outside through b.

Therefore, when a gas such as a toxic gas is transferred using the rotary vane pump, the degree of vacuum in the housing 20 is increased to a predetermined value or more, and the gas is supplied from the outside of the housing 20 to the inside thereof through the gaps 30a and 30b. I continue to inhale. Then, a gas such as a toxic gas passing through the housing 20 passes through the gaps 30a and 30b and the housing 20
It prevents it from leaking outside.

[0009]

By the way, when a large amount of a gas such as a toxic gas, which is troublesome when leaking to the outside using a rotary vane pump, is transferred, the degree of vacuum in the housing 20 drops below a predetermined value. Then, the gap 3 on the gas inlet side
The suction amount of the gas sucked into the housing 20 through the opening 0a passes through the gap 30b on the side of the gas discharge port and the housing 2
The discharge amount of the gas discharged from the inside of the housing 0 to the outside thereof is larger than that of the housing 20, and the housing 20 passes through the gaps 30a and 30b.
A gas such as a toxic gas passing through the inside leaks out of the housing 20.

The present invention has been made in view of the above problems, and when a large amount of gas such as toxic gas is transferred using a rotary vane pump in a state where the degree of vacuum in the housing is lowered, An object of the present invention is to provide a rotary vane pump capable of preventing a gas such as a toxic gas passing through the housing from leaking out of the housing through a gap around the rotary shaft of the rotor inserted into the shaft hole of the housing side wall.

[0011]

In order to achieve the above object, a rotary vane pump according to the present invention has a rotary shaft of a rotor in a shaft hole opened in a side wall of a housing accommodating a rotor having a vane fitted therein. In a rotary vane pump, which is inserted with a gap, and whose rotation shaft end is rotatably supported by a bearing portion provided outside the housing via a bearing, around the rotation shaft of the rotor outside the housing side wall. An airtight chamber communicating with the gap of the housing and communicating with the outside of the housing is provided so as to cover the gap around the rotating shaft of the rotor, and the airtight chamber is provided to the gas suction port side vacuum system of the rotary vane pump through an orifice. It is characterized by communication.

The rotary vane pump of the present invention is preferably equipped with an auxiliary vacuum pump for sucking and removing gas in the hermetic chamber.

[0013]

In the rotary vane pump having the above structure, when the rotor is rotated, the gas in the airtight chamber is continuously sucked into the housing through the gas suction port side vacuum system of the rotary vane pump communicating with the airtight chamber through the orifice. To be Then, even when the degree of vacuum inside the housing is lowered, the atmospheric pressure inside the airtight chamber is suppressed to be lower than the atmospheric pressure outside the housing.

Therefore, when a gas such as a toxic gas is transferred using a rotary vane pump in a state where the degree of vacuum in the housing is lowered, the gas is sucked into the housing through a gap on the gas suction port side around the rotation axis of the rotor. The amount of gas discharged from the inside of the housing to the outside through the gap on the gas discharge port side around the rotor's rotation axis is superior to the amount of gas suctioned, and communication with the gap around the rotor's rotation axis occurs. Even if the gas passing through the housing leaks into the airtight chamber, the air pressure inside the airtight chamber is kept lower than the air pressure outside the housing as described above. It is prevented from leaking out of the housing. In other words, the gas such as the toxic gas that has leaked into the airtight chamber does not leak to the outside of the housing, and the gas such as the atmosphere outside the housing continues to flow back into the airtight chamber.

When a rotary vane pump is used to transfer a gas such as a toxic gas in a state in which the degree of vacuum in the housing is increased, the gas is sucked into the housing through a gap on the gas suction port side around the rotary shaft of the rotor. The amount of gas discharged from the inside of the housing to the outside through the gap on the gas discharge port side around the rotor's rotating shaft is inferior to the amount of gas sucked in. Gas such as the atmosphere outside the housing continues to flow back into the housing through the gap.

In other words, in the rotary vane pump having the above structure, when a gas such as a toxic gas is transferred using the rotary vane pump, regardless of the degree of vacuum in the housing, the gap around the rotary shaft of the rotor and the air Gas such as toxic gas passing through the housing through the closed chamber is prevented from leaking out of the housing.

Further, in the rotary vane pump having the above described auxiliary vacuum pump for sucking and removing the gas in the airtight chamber, the orifice is removed from the airtight chamber at the time of starting the rotary vane pump in which the degree of vacuum in the housing is still low. The auxiliary vacuum pump is used when the pressure inside the airtight chamber cannot be kept sufficiently lower than the pressure outside the housing due to the small amount of gas sucked into the housing through the vacuum system on the gas inlet side of the rotary vane pump. By sucking and removing the gas in the airtight chamber, the air pressure in the airtight chamber can be kept sufficiently lower than the air pressure outside the housing. Then, when the rotary vane pump in which the degree of vacuum in the housing is still low is started, it is possible to prevent gas such as toxic gas flowing out of the housing into the airtight chamber from leaking out of the housing.

[0018]

Embodiments of the present invention will now be described with reference to the drawings. 1 to 3 show a preferred embodiment of the rotary vane pump of the present invention, and FIG. 1 is an enlarged cross-sectional view around the airtight chamber,
2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a partially cutaway front view thereof. The rotary vane pump will be described below.

In the rotary vane pump shown in the drawing, outside the housing side wall 20a is communicated with the gaps 30a and 30b around the rotary shaft 10 of the rotor inserted into the shaft hole 22, and
An airtight chamber 60 communicating with the outside of the housing 20 is provided so as to cover the gaps 30a and 30b around the rotary shaft 10 of the rotor.

Specifically, the airtight chamber 60 is provided with a housing side wall 20a around the shaft hole 22, a cylindrical body 62 provided upright on the side wall 20a so as to surround the rotary shaft 10 of the rotor, and the cylindrical body 62. And a lid 64 that covers the outer opening of the.

The cylindrical body 62 is a bearing portion 40 for rotatably supporting the end portion of the rotor rotating shaft 10 via a bearing 42.
Is also used as a support member for fixing to the housing side wall 20a.

A loose insertion hole 66 is opened in the center of the lid 64, and a middle portion of the rotary shaft 10 of the rotor is loosely inserted into the loose insertion hole 66 with a gap 70 formed around the middle portion.

A communication hole 44 is formed in the body portion of the bearing portion 40 to connect the space inside the bearing portion 40 holding the bearing 42 and the outside of the housing 20. The airtight chamber 60 is communicated with the outside of the housing 20 through the communication hole 44, the inner space of the bearing 40, and the space 70 around the rotary shaft 10 of the rotor inserted through the loose insertion hole 66.

The airtight chamber 60 communicates with a gas suction port side vacuum system 92 of the rotary vane pump through an orifice 80. Here, the gas suction port side vacuum system 92 refers to the gas suction port 90 of the rotary vane pump and the inner peripheral wall portion of the housing 20 which is connected to the gas suction port 90 and is arcuately suctioned.
Specifically, as shown in FIG. 3, a gas passage 68 is opened in a tubular body 62 forming a side wall of the airtight chamber 60, and the passage 68 is used as a gas suction of a rotary vane pump using a pipe 100. It is connected to, for example, the gas suction port 90 of the mouth side vacuum system 92. An orifice 80 is provided in the middle of the pipeline 100 to reduce the inner diameter of the pipeline 100 to a small diameter and to suppress the amount of gas passing through the pipeline 100 to a certain amount or less.

In addition, in the rotary vane pump shown in the figure, an auxiliary vacuum pump 110 for sucking and removing the gas in the airtight chamber 60 is used.
Is equipped with. Specifically, for example, as shown in FIG. 3, the check valve 102 is provided in the middle of the pipeline 100 connecting the orifice 80 and the gas suction port side vacuum system 92, and the same pipeline is provided. A bypass pipe 120 is provided at a midway portion of the pipe 100 across the check valve 102 so that both ends of the bypass pipe 120 communicate with the pipe 100. In the middle of the bypass pipeline 120,
The auxiliary vacuum pump 110 is provided. Then, by operating the auxiliary vacuum pump 110, the bypass line 1
The gas in the airtight chamber 60 is sucked into the gas suction port side vacuum system 92 through the pipe 20 and the pipe 100 to be removed, so that the air pressure in the airtight chamber 60 can be kept lower than the air pressure outside the housing 20. . At the same time, when the auxiliary vacuum pump 110 is operated by the check valve 102, the gas sucked and removed from the inside of the airtight chamber 60 into the bypass line 120 and the midway part of the bypass line 100 communicating with the bypass line 120. And a gas such as a toxic gas that passes through the gas suction port side vacuum system 92 and is prevented from being sucked into the gas suction port side vacuum system 92 through the pipe 100 and not being excluded. However, it prevents the gas from entering the airtight chamber 60 through the conduit 100 and leaking to the outside of the housing 20.

The rotary vane pump shown in FIGS. 1 to 3 is constructed as described above.

Next, an example of its use and its operation will be described.

One end of a transfer pipe (not shown) for transferring a gas such as a toxic gas is connected to the gas inlet 90 of the rotary vane pump, and the other end of the transfer pipe is connected to the gas discharge port of the rotary vane pump. Connect to 130.

Next, the rotor 12 having the vanes 14 fitted therein is rotated in the housing 20 together with the rotating shaft 10. Then, a suction force for sucking gas into the housing 20 is generated in the gas suction port side vacuum system 92.

Then, the gas in the airtight chamber 60 changes to the airtight chamber 6
0 is continuously sucked into the housing 20 through the gas suction port-side vacuum system 92 of the rotary vane pump which is communicated with the No. 0 through the orifice 80. Then, the air pressure inside the airtight chamber 60 is suppressed to be lower than the air pressure outside the housing 20. Then, when the rotary vane pump is operated in a state where the degree of vacuum in the housing 20 is lowered, the housing 2 is passed through the gaps 30a and 30b around the rotary shaft 10 of the rotor inserted into the shaft hole 22.
Even if a gas such as a toxic gas passing through the inside of the housing 0 leaks to the airtight chamber 60, the leaked gas does not leak to the outside of the housing 20 through the airtight chamber 60, and the gas such as the atmosphere outside the housing 20 does not leak to the airtight chamber. Continue to flow back into 60. Further, when the rotary vane pump is operated in a state where the degree of vacuum inside the housing 20 is increased, the air and the like outside the housing 20 is passed through the gaps 30a and 30b around the rotary shaft 10 of the rotor inserted into the airtight chamber 60 and the shaft hole 22. Gas is housing 20
Continue to flow back in. In addition, regardless of whether the degree of vacuum inside the housing 20 is high or low, gas such as toxic gas that passes through the housing 20 is prevented from leaking to the outside of the housing 20.

At the same time, a gas such as a toxic gas is sucked into the housing 20 through the transfer pipe and the gas suction port 90 connecting the gas and is compressed in the housing 20, and the compressed gas is discharged through the gas discharge port. It is delivered through 130 into a transfer pipe connected to it.

At the time of starting the rotary vane pump, the auxiliary vacuum pump 110 is operated to continuously suck and remove the gas in the airtight chamber 60 to the outside of the airtight chamber 60.

Then, at the time of starting the rotary vane pump in which the degree of vacuum in the housing 20 is still low, the suction force of the gas sucked into the housing 20 through the gas suction port side vacuum system 92 is weak and the gas suction port side vacuum system 92. In a state where the air pressure inside the airtight chamber 60 communicating with the pipe 100 and the orifice 80 or the like cannot be kept sufficiently lower than the air pressure outside the housing 20, the air pressure inside the airtight chamber 60 is complemented by the auxiliary vacuum pump 110. Is sufficiently lower than the atmospheric pressure outside the housing 20. And the housing 20
When the rotary vane pump in which the degree of vacuum is still low is started, gas such as toxic gas flowing out of the housing 20 into the airtight chamber 60 is prevented from leaking out of the housing 20.

In this rotary vane pump, when the diameter of the orifice 80 is set to a large value and a large amount of gas in the airtight chamber 60 is sucked and removed, the gas is sucked into the housing 20 through the gas suction port 90. Since the intake amount of gas such as poisonous gas is reduced and the performance of the rotary vane pump is deteriorated, the airtight chamber 6 is not operated during the steady operation of the rotary vane pump.
The diameter of the orifice 80 is preferably kept as small as possible so that the minimum necessary suction amount of gas in which the atmospheric pressure inside 0 becomes equal to or lower than the atmospheric pressure outside the housing 20 is sucked from the airtight chamber 60. FIG. 4 shows the atmospheric pressure inside the airtight chamber 60 with respect to the diameter of the orifice 80 when the atmospheric pressure outside the housing 20 is 0, when the atmospheric pressure is higher than that is positive pressure, and when the atmospheric pressure is lower than that is negative pressure. Rotary vane pump housing 2
The correlation with the degree of vacuum in 0 is shown. The one-dot chain line shows the case where the diameter of the orifice 80 is too small, the one shown by the solid line shows the case where the diameter of the orifice 80 is appropriate, and the broken line. What is shown by means the case where the diameter of the orifice 80 is too large.

When the rotary vane pump is started, a gas such as a toxic gas flowing from the inside of the housing 20 into the airtight chamber 60 through the gaps 30a and 30b around the rotary shaft 10 of the rotor may slightly leak out of the airtight chamber 60. Alternatively, when the rotary vane pump is continuously operated for a long time without being stopped, the gas in the airtight chamber 60 is removed at the time of starting the rotary vane pump, and the air pressure in the airtight chamber 60 is adjusted to the outside of the housing 20. The auxiliary vacuum pump 110 for keeping the pressure lower than the atmospheric pressure may not be provided.

[0036]

As described above, according to the rotary vane pump of the present invention, when a gas such as a toxic gas is transferred by using the rotary vane pump, the inside of the housing is irrespective of the degree of vacuum in the housing. It is possible to properly prevent gas such as toxic gas that passes through the housing from leaking out of the housing through a gap around the rotation axis of the rotor inserted into the shaft hole of the housing side wall.

Further, in the rotary vane pump of the present invention provided with the auxiliary vacuum pump for sucking and removing the gas in the airtight chamber, the atmospheric pressure in the airtight chamber is adjusted when the rotary vane pump in which the vacuum degree in the housing is still low is started. By suppressing the pressure to be lower than the atmospheric pressure of the outside, it is possible to accurately prevent gas such as toxic gas from leaking from the inside of the housing to the outside through the gap around the rotation axis of the rotor inserted into the shaft hole of the housing side wall and the airtight chamber.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view around an airtight chamber of a rotary vane pump of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partially cutaway front view of the rotary vane pump of the present invention.

FIG. 4 is an explanatory diagram showing a correlation between the air pressure in the airtight chamber and the degree of vacuum in the housing of the rotary vane pump with respect to the diameter of the orifice.

FIG. 5 is an enlarged sectional view around a shaft hole through which a rotary shaft of a rotor of a conventional rotary vane pump is inserted.

6 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 10 Rotor Shaft 12 Rotor 14 Vanes 20 Housing 20a Housing Side Wall 22 Shaft Holes 30a, 30b Gap 40 Bearing Portion 42 Bearing 44 Communication Hole 50 Rib 60 Airtight Chamber 66 Free Insertion Hole 70 Gap 80 Orifice 90 Gas Suction Port 92 Gas Suction Port 92 Side vacuum system 100 Pipe line 102 Check valve 110 Auxiliary vacuum pump 120 Bypass pipe line 130 Gas discharge port

Claims (2)

[Claims] 1. A rotary shaft of the rotor is inserted into a shaft hole opened in a side wall of a housing accommodating a rotor in which a vane is inserted with a gap around the shaft, and an end of the rotary shaft is provided outside the housing. In a rotary vane pump rotatably supported by a bearing portion via a bearing, an airtight chamber communicating with the outside of the housing side wall and a gap around the rotating shaft of the rotor and communicating with the outside of the housing is provided in the rotor. A rotary vane pump, which is provided so as to cover a gap around a rotary shaft, and the airtight chamber is communicated with a vacuum system on a gas suction port side of the rotary vane pump through an orifice. 2. The rotary vane pump according to claim 1, further comprising an auxiliary vacuum pump that sucks and removes gas in the airtight chamber.