JP2001227487A - Multi-stage roots vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multistage roots vacuum pump configured to effect a vacuum suction action in a preceding stage chamber and a pressurizing action in a subsequent stage chamber, with improved volumetric efficiency and a lower temperature of a pump body. SOLUTION: Inlets 28, 29 for outside or cooling air are provided at position t moved 60 deg. toward a suction port from position o which has gone beyond a volumetric displacement angle of 120 deg. in a direction opposite to the suction port 22 from respective centers of rotary shafts 4, 5 relative to a virtual line m of the stage chamber (second stage chamber y) effecting the vacuum action immediately followed by the pressurizing action effected by the final stage chamber (third stage chamber z). Accordingly, this one multi-stage (three-stage) roots vacuum pump thus configured effects the vacuum and pressurizing actions at the same time and increases supply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage roots vacuum pump used for a vacuum sewer system in an agricultural settlement, a furnace of an incineration plant, and the like.

[0002]

2. Description of the Related Art In a conventional roots type vacuum pump,
When a vacuum differential pressure of -0.047 MPa or more is generated between the suction port side and the discharge port side, the temperature of the casing on the discharge port side becomes about 120 to 150 ° C due to the heat of compression. In order to prevent troubles caused by the rise in temperature, manufacturers around the world began to provide air or cold air inlets in casings to cool the temperature to 120 ° C or lower. Has been taken in various ways. In the vacuum sewer system in agricultural settlements, a dedicated vacuum pump is installed to reduce the pressure inside the water collection tank, but if the exhaust from the vacuum pump is released to the atmosphere as it is, it will cause a bad smell, so it will pass through the deodorizing device After being released into the atmosphere. In the sewage treatment tank connected to the water collection tank, sewage treatment is performed by a dedicated aeration blower. The present applicant has a patent right of Japanese Patent No. 2684526 for a vacuum-type wastewater collecting and draining device. Has been disclosed. In a device for supplying air containing high-concentration oxygen into a furnace such as an incineration facility, a dedicated vacuum pump and a blower for pressure feeding are provided respectively. The present applicant has a patent right of patent No. 1719471 (Japanese Patent Publication No. 4-2297) for an oxygen-enriched air supply device used for boiler heavy oil combustion burners, aeration of sewage water, etc., and one Roots blower. Are proposed as two groups, a vacuum blower and a compression blower.

[0003]

In the above-mentioned conventional Roots type vacuum pump used for a vacuum sewer system or an incineration facility, when an air or cooling air inlet is provided in the area of the volume movement angle, The reduction in volumetric efficiency and mechanical efficiency was inevitable. Further, in the case where both a vacuum pump and a pressure blower are installed as in the air supply device in the incineration facility, there are problems such as high equipment and operating costs and a large installation space.

An object of the present invention is to provide a multi-stage roots vacuum pump having a structure in which a vacuum suction operation is performed in a front chamber and a pressurizing function is performed in a rear chamber, and at the same time, volume efficiency is improved and the temperature of a pump body is reduced. Is to do.

[0005]

In order to achieve the above object, according to the present invention, a pair of three-leaf rotors are provided in a casing having a suction port and a discharge port, and a suction port and a discharge port are provided. A multi-stage roots vacuum pump comprising at least two or more chambers for sucking air from a suction port by rotating both rotors so as not to communicate with each other and discharging the sucked air from a discharge port, The suction port is provided at a position n which is more than 120 ° of the volume movement angle from the center of each rotation axis with respect to a virtual line m connecting the center of the rotation axis of each rotor, and the discharge port is provided at the rotation axis of each rotor. From a position o which exceeds a volume movement angle of 120 ° in a direction opposite to the suction port from the center of each rotation axis with respect to an imaginary line m connecting the centers of Perimeter of area up to intersection q A closed space provided by forming at least one air passage hole in a wall portion, and immediately after suction of air, enclosed at two locations on the suction port side and the discharge port side by adjacent leaf pieces of each rotor and an inner wall surface of a casing. In the direction opposite to the suction port from the center of each rotary shaft with respect to the imaginary line m on the discharge port side of the step chamber that generates a vacuum action immediately before the final step chamber that generates a pressurizing action. An inlet port for outside air or cooling air is provided on a peripheral wall portion at a position t which is returned by 60 ° to a suction port side from a position o exceeding a volume movement angle of 120 °.

[0006]

According to the present invention, a vacuum chamber is provided with an inlet for outside air or cooling air immediately before the final chamber in which a pressurizing action is generated. It is possible to simultaneously generate a pressurizing action and increase the feed rate.

The total volume movement angle of the enclosed space surrounded by the adjacent leaf pieces of each rotor and the casing inner wall surface is 240 °, which is twice the volume movement angle of 120 °, and the top of the rotor leaf pieces and the casing inner wall surface. And the timing at which the air on the discharge port side flows into the closed space is delayed. For this reason, the amount of internal leak is reduced, the volumetric efficiency is improved, and the heat generated by the compression action is concentrated on the discharge port portion, thereby suppressing a rise in the temperature of the pump body.

This multi-stage roots vacuum pump has a structure in which a vacuum suction operation is performed in the front chamber and a pressure operation is performed in the rear chamber, so that a single unit can simultaneously generate vacuum and pressurization. In addition, it is possible to improve the volumetric efficiency and lower the temperature of the pump body.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a configuration diagram of a three-stage roots vacuum pump, FIG. 2 is a vertical side view of a first stage chamber x and a third stage chamber z, FIG. 3 is a vertical side view of a second stage chamber y, and FIG. FIG. 5 is an explanatory view showing situations (1) to (7) in which outside air or cooling air flows into an enclosed space surrounded by adjacent leaf pieces of each rotor and an inner wall surface of a casing in a two-stage chamber y, and FIG. FIG. 6 is an explanatory diagram showing a case where the three-stage roots vacuum pump of the present invention is used for a vacuum sewerage system, and FIG. 6 is an explanatory diagram showing a case where the three-stage roots vacuum pump of the present invention is used for an incinerator.

In FIG. 1, a three-stage roots type vacuum pump P has housings 2 and 3 mounted on both sides of a casing 1 in which a first stage chamber x, a second stage chamber y and a third stage chamber z are formed.
A timing gear 6 which rotatably supports two parallel rotating shafts 4 and 5 by the respective housings 2 and 3 and meshes with the respective shaft ends of the rotating shafts 4 and 5 protruding from one housing 2.
Are attached to each other, and a pulley 7 driven by a motor (not shown) is provided at a shaft end of one rotary shaft 4 protruding from the other housing 3. In such a basic configuration, the components of the first stage chamber x are in the 10s, the second stage y is in the 20s, and the third stage z
Are denoted by reference numerals in the thirties and will be described in detail below.

As shown in FIG. 2, a pair of three-leaf rotors 15 and 16 are provided in the first stage chamber x in a casing 1 having a suction port 12 and a discharge port 13 so as to be rotatable in opposite directions. The rotation of both rotors 15 and 16 sucks air from the suction port 12, compresses the sucked air, and discharges the compressed air from the discharge port 13. The inner wall surface 11 of the casing 1 and the rotors 15, 16
At the top of the leaf piece is a well-known small gap c
Is provided.

The suction port 12 is located at a position which exceeds a volume moving angle of 120 ° from the center of each of the rotating shafts 4 and 5 with respect to an imaginary line m connecting the centers of the rotating shafts 4 and 5 of each of the rotors 15 and 16. n has a horizontally long mouth portion 12a.

The discharge port 13 is connected to an imaginary line m connecting the centers of the rotation shafts 4 and 5 of the rotors 15 and 16 in a direction opposite to the suction port 12 from the center of the rotation shafts 4 and 5.
From the position o which exceeds the volume movement angle of
Is formed by forming at least one air passage hole 17 in the peripheral wall portion 11a of the region r up to the point q where the casing inner diameter circle intersects the center of the circle. s is the adjacent leaf piece of each rotor 15 and 16 and the casing inner wall surface 1
1 shows a closed space surrounded by.

In FIG. 2, the part indicated by reference numerals in the thirties is the configuration of the third stage chamber z which is the final stage chamber in which the pressurizing action is performed.

FIG. 3 shows a second stage chamber y which is a stage chamber in which a vacuum action is generated immediately before the third stage chamber z. This second stage chamber y
Has a casing 1 having a suction port 22 and a discharge port 23 formed therein.
A pair of three-lobe rotors 25 and 26 are rotatably provided in opposite directions, and the rotation of both rotors 25 and 26 sucks air from the suction port 22 and compresses the sucked air to discharge the air. It is configured to discharge from the outlet 23.

The suction port 22 is located at a position which exceeds a volume movement angle of 120 ° from the center of each of the rotating shafts 4 and 5 with respect to an imaginary line m connecting the centers of the rotating shafts 4 and 5 of each of the rotors 25 and 26. n has a horizontally long mouth 22a.

The discharge port 23 is connected to the imaginary line m connecting the centers of the rotation shafts 4 and 5 of the rotors 25 and 26 in a direction opposite to the suction port 22 from the center of the rotation shafts 4 and 5.
From the position o which exceeds the volume movement angle of
Is formed by forming at least one air passage hole 27 in the peripheral wall portion 21a in a region r up to a point q where the casing inner diameter circle intersects the center of the circle. The peripheral wall 21a on the side of the discharge port 23 sucks in from a position o which exceeds a volume movement angle of 120 ° in a direction opposite to the suction port 22 from the center of each of the rotary shafts 4 and 5 with respect to the virtual line m. At positions t that are returned by 60 ° to the port 22 side, inlet ports 28 and 29 for outside air or cooling air are provided.

As shown in FIG. 1, the discharge port 13 of the first chamber x is connected to the suction port 22 of the second chamber y via a pipe 40, and the discharge port 23 of the second chamber y is connected to the third port y. Inlet 32 of step chamber z
Are connected by a pipe 41.

FIG. 4 shows that each rotor 2 is located in the second stage chamber y.
The situations (1) to (7) in which the outside air or the cooling air flows into the closed space s surrounded by the adjacent leaf pieces 5 and 26 and the inner wall surface 21 of the casing are shown. In the figure, the hatched portions indicate the locations where the outside air (or cooling air) from the respective inlets 28 and 29 flows into the closed space s that moves as the rotors 25 and 26 rotate.

Next, the case where the three-stage roots vacuum pump P of the present invention having the above-described structure is used in a vacuum sewer system will be described. In FIG. 5, the three-stage roots type vacuum pump P has its suction port 12 connected to the water collecting tank 50 via a check valve 52 via a suction pipe 51, while the discharge port 33 has a check valve 54 via a discharge pipe 53. Aeration tank 6 for sewage treatment
0 is connected to the air diffuser 61. 55 is a silencer connected to the inlets 28 and 29 of the vacuum pump P. The collection tank 50 is connected to a pipeline 56 for collecting sewage from the settlement and a water supply pipe 57 to an aeration tank 60 for sewage treatment.

In the above vacuum sewer system, when the three-stage roots type vacuum pump P is operated, the pressure inside the water collecting tank 50 is reduced by the vacuum action of the vacuum pump P, so that sewage flows in from the pipe 55. The air sucked from the water collecting tank 50 is compressed to a set vacuum pressure in the first stage chamber x and the second stage room y. Note that the suction air at this time is lean and retains heat due to the compression action. Inlet 2 in second stage room y
The outside air from 8, 8 is sucked, and the outside air mixes with the suction air to lower the temperature of the heat of compression and to replenish the air. Next, the cooled air is pressurized in the third stage chamber z and sent to the air diffuser 61 from the discharge port 33, and the sewage w
Aeration.

The case where the three-stage roots vacuum pump P of the present invention is used in an incinerator of an incineration facility will be described. In FIG. 6, a three-stage roots vacuum pump P has its suction port 12 connected to an oxygen-enriched membrane device 80 by a suction pipe 71,
The discharge port 33 is connected to an incinerator 85 by a discharge pipe 72. A cooler 73 such as an intercooler is connected to the discharge port 23 of the second stage chamber y of the vacuum pump P, and the outlet side of the cooler 73 is connected to the inlets 28, 2, 2
9 is connected.

In the above incinerator, when the three-stage roots vacuum pump P is operated, the inside of the oxygen-enriched membrane device 80 is reduced to a predetermined pressure by the vacuum action of the vacuum pump P.
The air taken in from the outside has a high oxygen concentration,
It is compressed in the stage chamber x and the second stage room y. Part of the air containing high-concentration oxygen having compression heat from the discharge port 23 of the second stage chamber y is diverted to the cooler 73, cooled by the cooler 73, and returned from the inlets 28 and 29 to the second stage again. Returned to room y. Next, the air containing high-concentration oxygen is pressurized in the third stage chamber z and sent to the incinerator 85 from the discharge port 33. Thus, in the incinerator 85, air containing high-concentration oxygen is supplied, so that the combustion efficiency is improved, and the combustion temperature is increased, thereby suppressing the generation of harmful substances such as dioxin.

As described above, according to this multi-stage roots vacuum pump, a vacuum suction action is generated in the first chamber (first and second chambers x and y), and a pressurizing action is generated in the second chamber (third chamber z). With the structure, the vacuum and pressurizing actions can be simultaneously generated by one unit.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a three-stage roots vacuum pump.

FIG. 2 is a longitudinal sectional side view of a first chamber x and a third chamber z.

FIG. 3 is a vertical side view of a second stage chamber y.

FIG. 4 is an explanatory view showing situations (1) to (7) in which outside air or cooling air flows into and moves into a sealed space surrounded by adjacent leaf pieces of each rotor and an inner wall surface of a casing in a second stage chamber y.

FIG. 5 is an explanatory diagram showing a case where the three-stage roots vacuum pump of the present invention is used in a vacuum sewer system.

FIG. 6 is an explanatory view showing a case where the three-stage roots vacuum pump of the present invention is used in an incinerator.

[Explanation of symbols]

P → Multi-stage roots type vacuum pump c → Small gap m → Virtual line n connecting the center of the rotation axis of each rotor n → 120 ° from the center of each rotation axis to virtual line m
The position exceeding the volume movement angle of o → the position beyond the volume movement angle of 120 ° from the center of each rotation axis to the virtual line m in the direction opposite to the suction port q → the center of each rotation axis The intersection point of the inner diameter circle of the casing r → the area (on the discharge port side) s → the closed space t → the volume movement angle of 120 ° has been exceeded from the center of each rotation axis to the virtual line m in the direction opposite to the suction port. A position 60 ° returned from the position o to the suction port side 1 → casing x → first stage room y → second stage room z → third stage room 4,5 → rotary shaft 11, 21, 31 → inner wall surface 11a, 21a, 31a → peripheral wall portions 12, 22, 32 → suction ports 13, 23, 33 → discharge ports 15, 16, 25, 26, 35, 36 → rotors 17, 27, 37 → air passage holes 28, 29 → introduction ports

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F04C 29/04 F04C 29/04 E (72) Inventor Koichi Kume Kaniecho, Kaifu-gun, Aichi Prefecture No. 160 No. 1 in Anlet Co., Ltd. (72) Inventor Yoshinobu Ito Kanie-cho, Kaifu-gun, Aichi Prefecture, Kanie-Honcho, No. 160 No. 1 In Anlet Co., Ltd. (72) Inventor Yuji Nagai, Kanie-cho, Aichi Prefecture 160-No.1, Kanie-Honcho, E-cho, in the town Antolet Co., Ltd. (72) Inventor Masami Kato Masami Kato, Kanie-cho, Kaifu-gun, Aichi Prefecture 160-No.1, Honai, Kanie-Honcho, No. 1 In Anlet Co., Ltd. (72) Inventor Toya Haruo Aichi Prefecture Kanie-cho Kanie-cho O-Kanai Honmachi character E-no 160-in-1 Anlet Co., Ltd. (72) Inventor Takashi Yokoi Aichi-ken Kanie-cho, Kaifu-gun Oji Kanie-Honcho, No. 160-1 F-term in Inlet Inc. (Reference) 2D063 AA07 DC04 3H029 AA06 AA17 AA23 AB02 BB42 CC24 CC25 CC47

Claims (1)

[Claims] 1. A pair of three-leaf rotors are provided in a casing having a suction port and a discharge port, and both rotors are rotated so that communication between the suction port and the discharge port is prevented. And a multi-stage roots vacuum pump comprising at least two or more chambers for sucking air and discharging the sucked air from a discharge port, wherein each of the suction ports is defined by an imaginary line m connecting the center of the rotation axis of each rotor. 120 from center of rotation axis
°, and the discharge port is located at a position opposite to the suction port from the center of each rotation axis with respect to an imaginary line m connecting the center of the rotation axis of each rotor.
At least one air passage hole is formed in a peripheral wall portion in a region from a position o exceeding a volume movement angle of ° to a point q where a casing inner diameter circle intersects the center of each rotation axis as a center, Immediately after the air is sucked, an airtight space is formed in two places on the suction port side and the discharge port side which are surrounded by the adjacent leaf pieces of each rotor and the inner wall surface of the casing, and immediately before the final stage chamber in which the pressurizing action is generated. With respect to the imaginary line m on the discharge port side of the step chamber where the vacuum action occurs, from the center of each axis of rotation exceeds the volume movement angle of 120 ° in the direction opposite to the suction port from the center o to the suction port side. A multi-stage roots vacuum pump, characterized in that an inlet for outside air or cooling air is provided in a peripheral wall portion at a position t returned by a degree.