JPH087113Y2 - Water-sealed vacuum pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement of a water-sealed vacuum pump.

[Conventional technology]

As is well known, a liquid (for example, water) in a casing is rotated by an impeller, and as the liquid moves in a radial direction of the impeller, a gas (for example, air) is sucked in and discharged, and is pumped or discharged. A sealed vacuum pump is known, and a plurality of such pumps are used so that the exhaust port of the first-stage pump and the intake port of the second-stage pump communicate with each other so that a higher degree of vacuum than that of the first-stage pump can be obtained. Various two-stage water-sealed vacuum pumps have been proposed.

The two-stage water-sealed vacuum pump of this type includes a one-rotor and two-stage type as shown in FIG.
There is a stage type, of which the one shown in FIG. 5 has an impeller (104) in a casing (103) between a first stage pump section (101) and a second stage pump section (102). The 1st-stage side impeller (104a) and the 2nd-stage side impeller (104b) on the same rotary shaft are arranged in each casing partitioned by the 1st-stage side pump section. (Ten
The exhaust port of 1) and the intake port of the second-stage pump section (102) are connected by a tube or the like (not shown).

[Problems to be solved by the device]

However, the conventional water-sealed vacuum pump has a problem as pointed out below.

FIG. 6 is an explanatory view showing the structure of a water-sealed vacuum pump,
(103a) is the inner peripheral surface of the casing, (106) is the intake port, (107) is the exhaust port, (P) is the center of the impeller,
(O) shows the center of the casing, (F) shows the water sealing surface during rotation of the impeller, and (G) shows the gap volume.

The above water-sealed vacuum pump is theoretically considered to be a reciprocating pump. That is, the impeller is in the cylinder,
The sealing surface corresponds to the piston, and the intake / exhaust port corresponds to the intake / exhaust valve. In such a pump, a certain amount of pressurized air remains after the exhaust valve, that is, the exhaust port is closed, and the space called the gap volume of the residual air becomes a factor that deteriorates the pump performance. This brings about a result that the high pressure air on the exhaust side remaining in the clearance volume moves to the intake side and expands, thereby reducing the intake air amount. Therefore, although the pump performance can be improved as the above-mentioned gap volume is reduced, it is considerably difficult from the viewpoint of processing technology to reduce the gap volume in the structure of the conventional water-sealed vacuum pump.

[Means for solving the problem]

In the water-sealed vacuum pump, in order to reduce the gap volume inside the casing, a water passage for directly supplying water is provided at the close point between the intake port and the exhaust port.

[Action]

According to this invention, since the air remaining in the gap volume after the exhaust port is closed can be removed by the water supply from the water passage, the residual air is greatly reduced and the gap volume is also reduced. Therefore, the amount of intake air from the intake port is increased and the pump performance is improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The two-stage water-sealed vacuum pump (A) of FIG. 1 comprises a first-stage vacuum pump section (B), a second-stage pump section (C), and a bearing section (D), as shown in the sectional view. However, the impeller (2) is provided between the first-stage pump section (B) and the second-stage pump section (C).

This impeller (2) has a circular partition plate (2a) for partitioning the inside of the casing (1), as shown in FIGS. 1 and 3.
And a first-stage side impeller (2b) and a second-stage side impeller (2c) respectively arranged on the left and right sides thereof, and the partition plate (2a) is rotatably provided and the partition plate ( 2
It has an integrated structure in which a) is provided with a first-stage impeller (2b) and a second-stage impeller (2c). Those first-stage impellers (2
In b) and the second-stage impeller (2c), radially arranged blades (2d) are arranged symmetrically with respect to the partition plate (2a).
The entire impeller (2) is fixed to the rotary shaft (3) with bolts (4) and is arranged eccentrically with respect to the central axis in the casing (1). Further, since the first-stage pump section (B) has a higher vacuum than the second-stage pump section (C), the first-stage impeller (2b) has a higher vacuum.
It is wider than c).

The first-stage pump section (B) has a casing (1) and an intake-side housing (5), and the second-stage pump section (C) has a casing (1) and an exhaust-side housing (6).
It consists of.

The intake-side housing (5) and the exhaust-side housing (6) are in a state of being connected to the bearing portion (D) by a plurality of bolts (7) via the casing (1). Is provided with a bearing (not shown) that rotatably supports the rotating shaft (3), while a motor is provided on the opposite side of the pump portion via a pulley.

As shown in FIG. 1 and FIG. 2, the intake side housing (5) has a water supply port (5a) formed at the center and an intake port (5b) on the upper side and a first stage intake port (5c) on the upper side. It is formed to communicate. Further, an exhaust port (5d) is formed below it so as to communicate with the first-stage exhaust port (5e), and the second-stage pump section (C) is connected from this exhaust port (5d) by a connecting pipe or the like not shown. It is connected to the intake port (6a).

As shown in FIGS. 1 and 3, the casing (1) has a substantially circular shape with the center of the inner wall eccentric, and the partition plate (2a) of the impeller (2) is located at the center from the two-stage side. Is provided with a partition part (1a) for partitioning the inside of the casing (1). This partition (1a) is the difference between the outer circumference of the impeller (2) and the inner circumference of the casing (1), and the outer circumference of the partition plate (2a) is attached to the inner circumference (1b) of the partition (1a). The surfaces are in sliding contact with each other or have a slight gap.

In the lower part of the casing (1), a water passage (1) for supplying water to the first-stage pump section (B) and the second-stage pump section (C) is provided.
c) and (1d) are provided. This waterway (1c) and (1
The water supply point in d) is the gap volume (G) (hatched portion in FIG. 3).
Is set to.

As shown in FIGS. 1 and 4, the exhaust side housing (6) has a hole (6c) for accommodating the mechanical seal (8) in the center thereof, and an upper stage pump section (B) is formed above the hole (6c). )
The second-stage intake port (6a) connected to the exhaust port (5b) is formed so as to communicate with the second-stage intake port (6b). Further, a second-stage exhaust port (6d) is formed below it, and an exhaust passage (6e) and an exhaust port (6f) communicating with this are provided. In the figure, (14) is a draining plate attached to the rotating shaft (3).

Next, the operation and action of this two-stage water-sealed vacuum pump (A) will be described.

When water is supplied from the water inlet (5a) and the rotating shaft (3) is rotated by a motor (not shown) to rotate the impeller (2), the water in the casing (1) moves along the inner peripheral wall of the casing (1). Flow and rotate in a ring. Since the center of the impeller (2) is eccentric with respect to the center of the inner peripheral wall of the casing (1), a space is formed on the upper side. This space expands and contracts as the impeller rotates, so that air is sucked and discharged.

Here, the flow of air will be described. Air from the intake port (5b) of the first-stage pump section (B) is sucked into the first-stage working chamber (1e) from the first-stage intake port (5c). 1
The air discharged from the stage working chamber (1e) passes through the connecting pipe (not shown) connected from the exhaust port (5e) to the exhaust port (5d), and then from the second stage intake port (6a) to the intake port (6b). ) And is sucked into the second stage working chamber (1f). Air discharged from the second-stage working chamber (1f) is discharged from the second-stage exhaust port (6
It passes through the passage (6e) from d) and is discharged to the outside through the exhaust port (6f).

Water is supplied to the gap volume (G) (see FIG. 3) in the first-stage casing and the second-stage casing simultaneously with the rotation of the impeller (2) and remains in the gap volume (G). By removing the high-pressure air on the exhaust side with this water pressure, the pump performance is improved.

Although the above embodiment is a port plate type of 1 rotor 2 stages, the present invention is not limited to this.
In a single-stage pump, it is also effective in preventing the residual air pressure of the exhaust side port from affecting the adjacent intake side port. Needless to say, it may be a 2-rotor 2-stage port cylinder type, and may be applied to a multistage water-sealed vacuum pump having three or more stages.

[Effect of device]

Since the present invention is configured as described above, it has the following effects.

By providing a water passage for directly supplying water to the clearance volume in the pump casing, the clearance volume can be reduced, and the amount of air in the exhaust side port that tends to remain in the clearance can be reduced or removed. Therefore, the exhaust pressure does not affect the intake side, the pump performance can be stabilized, and the performance can be dramatically improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment in which the present invention is applied to a two-stage water-sealed pump, FIG. 2 is a front view of an intake side housing, FIG. 3 is a front view of a casing, and FIG. The figure is a front view of the exhaust side housing. 5 and 6 relate to a conventional example, FIG. 5 is an explanatory view of a conventional two-stage water-sealed vacuum pump, and FIG. 6 is an explanatory view showing a structure of a gap volume portion. . (A) …… 2-stage water-sealed vacuum pump (B) …… First-stage pump section, (C) …… Second-stage pump section (1) …… Casing, (1c) …… First-stage water passage (1d) …… 2-stage water passage, (2) …… impeller (2a) …… divider, (2b) …… first-stage impeller (2c) …… second-stage impeller, (5d) …… exhaust Mouth (6a) …… Intake port

Claims (1)

[Scope of utility model registration request] 1. A water-sealed vacuum pump, characterized in that a water passage for directly supplying water is provided at a proximity point between an intake-side port and an exhaust-side port in order to reduce a clearance volume inside a casing of the water-sealed vacuum pump. .