JPS647262Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is a liquid ring pump, in which approximately half of water or other liquid is sealed in a normally oval casing with a built-in impeller. A pump in which a water film is formed along the inner surface of the casing by centrifugal force as the impeller rotates, and the pumping action is performed by changing the volume of each blade chamber whose periphery is sealed with the water film. In particular, the present invention relates to a two-stage liquid ring pump in which two impellers of the liquid ring pump are mounted on the pump shaft.

The liquid ring pump can be used as a low vacuum pump by connecting the first stage pump suction port to the evacuated chamber, or alternatively, the first stage suction port can be opened to the atmosphere and the second stage discharge port can be used as a low vacuum pump. This pressure air is used as a blower or compressor.

(Prior art) The conventional 2 impellers are mounted on the pump shaft.
As shown in the sectional view of main parts in Fig. 3, a staged liquid ring pump has a first stage (low pressure side) impeller 2 which is wide in the axial direction and a second stage impeller which is narrow in the axial direction on the pump shaft 1. A stage (high-pressure side) impeller 3 is mounted in a skewer-like manner in the same-shaped first and second stage oval casings 4 and 5 with a partition wall 8 in between. Gas inlets and outlets 2a and 3a are bored on the inner diameter side, and these inlets and outlets of the impeller are opposed to each other.
Port cylinders 6 and 7 having radial gas inlets and outlets are provided on the casing side.
The inlet of the first stage impeller is connected to the outside air when used as a blower, etc., and to the evacuated chamber when used as a vacuum pump, and the outlet is provided on the outside of the casing or on the partition wall. It is led to the inlet of the second-stage impeller through a passageway, the outlet of which is in communication with the blowing chamber or with the outside air, respectively, depending on the above-mentioned purpose.

The first casing 4 and the second casing 5 are separated by a partition wall 8, and an intermediate bushing 9 has a slight gap between the shaft 1 and the shaft 1 at the shaft penetrating portion of the partition wall 8. The intermediate bushing 9 is provided with a metal bushing or an oil seal.

During operation, when the pump shaft 1 rotates, both the first and second stage impellers 2 and 3 rotate together, and approximately The liquid sealed in half is circulated along the inner surface of each casing by centrifugal force, forming an elliptical water film having the same shape as the inner surface of the casing. The volume of each blade chamber defined by the water film and each adjacent blade changes due to the radial displacement (piston action) of the water film due to rotation,
When moving toward the long axis of the ellipse in each blade chamber (in this phase), the entrances and exits 2a and 3a are suction (vacuum)
Similarly, when moving toward the short axis, a discharge (compression) action is produced. As mentioned above, the outlet of the first stage is communicated with the inlet of the second stage, so the gas is sucked in through the inlet of the first stage, receives the pumping action of the two stages, and is discharged from the outlet of the second stage, thereby producing the required amount of gas. vacuum or blower action.

(Problems to be solved by the invention) As mentioned above, in the conventional two-stage liquid ring pump, a metal bushing or an oil seal is installed in the shaft penetrating part of the bulkhead that partitions the first and second stage casings. However, metal bushings (such as BC-6) cannot completely prevent pressure differences because there is a slight gap between the pump shaft and the bushing, and the oil seal also Since it is a contact type, there is a problem that the sealing effect inevitably deteriorates gradually due to deformation during operation, wear and tear, etc.

(Means for Solving the Problems) In order to solve the above-mentioned problems of the prior art, the present invention comprises an intermediate bushing inserted into the shaft penetrating portion of the stage spacer wall, made of metal or an elastic body, and It is characterized by having a water-sealing passage bored therein, and in implementation, the water-sealing passage is branched from the liquid film positive pressure part in the casing and passes through a passage provided in the partition wall, and then passes through the casing. The pressure water of the liquid film inside is supplied.

(Function) Since the present invention is configured as described above, the pumping action is performed by changing the volume of each blade chamber whose outside is sealed with liquid due to the rotation of the impeller during operation, unlike conventional systems. There isn't. Then, after passing through the interstage wall between the first stage casing and the second stage casing,
The high-pressure gas in the second-stage casing on the high-pressure side that attempts to leak into the first-stage casing on the low-pressure side is blocked by an intermediate bushing inserted into the shaft penetration part. A water passage is formed, and the pressurized water of the liquid film inside the casing is constantly supplied through the passage provided in the partition wall and is sealed with water during operation, so that gas leakage is completely prevented.

Further, if the intermediate bushing is made of an elastic material such as synthetic rubber, there is no risk of galling even if the rotating shaft is bent, and it can be used for a long period of time.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view of a two-stage liquid ring pump showing an embodiment of the present invention, and among the symbols shown in this drawing, the same ones as those shown in FIG. 3 are the same or Similar parts shall be indicated. In the figure, a first-stage impeller 2 with a wide axial width and a second-stage impeller 3 with a narrow width are placed on a pump shaft 1 with the same shape.
The elliptical casings 14 and 15 of the first and second stages are mounted in a skewer shape with a partition wall 18 in between, and a gas inlet/outlet 2a is provided on the inner diameter side of each impeller 2 and 3.
and 3a are bored, and port cylinders 6 and 7 having radial gas inlets and outlets are provided on the casing side opposite to these respective inlets and outlets of the impeller. The inlet of the first-stage impeller 2 is connected to the suction port 16 of the pump device, and the outlet of the second-stage impeller 3 is connected to the discharge port 17 of the pump device.

In this embodiment, in particular, the first stage casing 14 and the two
The intermediate bushing 20 inserted into the shaft penetrating portion of the partition wall 18 that partitions the stages of the stage casing 15 is made of an elastic material such as synthetic rubber, and as shown in the enlarged view of FIG. Self-sealing passage 20
A is drilled. Further, a slight gap is provided between the shaft 1 and the plurality of protrusions 20b protruding from the inner circumferential surface. And the self-sealing passage 20a
is connected to a passage 19 in a partition wall 18 that is branched from the liquid film positive pressure section in the first stage casing 14 . In addition, in the figure, 11 and 12 indicate mechanical seals.

According to this embodiment, the second stage casing 15 on the high pressure side tries to leak into the first stage casing 14 on the low pressure side through the interstage wall 18 between the first stage casing 14 and the second stage casing 15. The high-pressure gas is completely blocked by the water seal formed between the inner surface of the intermediate bushing 20 and the outer circumferential surface of the pump shaft 1, thereby creating a perfect seal between the stages and connecting the shaft 1 of the intermediate bushing 20 with the water seal. It also provides cooling protection for the seals. Moreover, since this water sealing uses the pressure water of the liquid film inside the casing, no special water supply source is required.

Furthermore, since the intermediate bushing 20 is made of an elastic material such as synthetic rubber, even if the pump shaft 1
Even if the intermediate bushing 2 is bent, there is no fear of galling and there is no problem with slight contact between the intermediate bushings 2 and 2.
0 and the pump shaft 1 can be made as small as possible. Therefore, leakage will be reduced accordingly.

In the above embodiments, an example in which the pump casing is formed into an elliptical shape has been described, but a liquid ring pump may also be constructed by eccentrically supporting an impeller inside a circular casing.

Further, instead of supplying water to the water sealing passage of the intermediate bush by extracting pressure water from the liquid film on the inner surface of the casing, it is also possible to supply water from the outside through a passage within the partition wall.

(Effects of the invention) As explained above, the invention provides the following effects.

(i) If the intermediate bushing constituting the seal member is made of an elastic material, there is no fear that it will seize even if the shaft is bent like a metal bushing, and there is no problem with slight contact between the intermediate bushing and the intermediate bushing. The gap with the rotating shaft can be made as small as possible. Therefore, interstage sealing can be further improved.

(ii) The intermediate bushing has an internal water sealing passage, and during operation, sealing water is supplied through the internal passage of the bulkhead, so that the seal between the stages of both the high-pressure side and low-pressure side casings is completely sealed. In addition, the contact portion of the intermediate bushing is protected from cooling.

Further, if the pressure water of the liquid film in the casing is branched and used for the water sealing, a special water supply source for water sealing becomes unnecessary, and the structure becomes simple.

(iii) Since the intermediate bushing is simple and has a large sealing effect as described above, it is possible to maintain a sufficient pressure difference between the first and second stage casings and improve pump efficiency.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a liquid ring pump showing an embodiment of the present invention, Fig. 2 is an enlarged sectional view of the main part of Fig. 1, and Fig. 3 is a main part of the lower half of a conventional liquid ring pump. FIG. 1...Pump shaft, 2...1st stage impeller, 3...
2nd stage impeller, 6, 7...Port cylinder, 14
... 1st stage casing, 15 ... 2nd stage casing, 18 ... Bulkhead, 20 ... Intermediate bushing, 20
a...Self-sealing passage.

Claims (1)

[Claims for Utility Model Registration] 1. In a two-stage liquid ring pump with two impellers mounted on the pump shaft, an intermediate bushing having a water-sealing passage inside is inserted into the shaft penetrating portion of the stage spacer. A liquid ring pump characterized in that a pressure difference between a first stage casing and a second stage casing is maintained. 2. The liquid ring pump according to claim 1, wherein the intermediate bushing is made of an elastic body. 3 In practical use, the water sealing passage of the intermediate bushing is supplied with pressure water of a liquid film formed in the casing during operation through a passage provided in the partition wall branching from the liquid film positive pressure part in the casing. A liquid ring pump according to claim 1 of the patent registration claim.