JP6785488B2 - Roots blower - Google Patents

Description

The present invention relates to a roots blower, and more particularly to a shaft seal portion of a rotating shaft of a rotor.

The roots blower has a suction port that opens on one side of an oval rotor chamber having a pair of arcuate surfaces and an intermediate surface of the rotor chamber, and a casing that forms a discharge port that opens on the other side. It has a pair of rotating rotors, and the rotating shaft of each rotor is rotatably supported by bearings in the casing. A shaft sealing portion is provided at a portion of the rotating shaft protruding from the rotor chamber to prevent the fluid in the rotor chamber from leaking to the outside of the rotor chamber.

As a form of the roots blower, Japanese Patent Application Laid-Open No. 6-101674 discloses a roots blower in which an oil seal is used for the shaft seal portion.
Further, Japanese Patent Application Laid-Open No. 47-22520 discloses a roots blower that employs a mechanical seal as a shaft sealing portion.

JP-A-6-101674 Jitsukaisho 47-22520

Since the oil seal is easy to assemble, the manufacturing cost can be reduced, but the lip portion of the oil seal is worn over the course of operation, causing a fluid leak in the rotor chamber. When a condensing gas such as steam or a corrosive gas leaks from the rotor chamber and drainage is generated, the drainage is mixed in the lubricating oil of the bearing and the timing gear, and the lubricating oil deteriorates. As a result, the durable life of bearings and timing gears is shortened and they are damaged early.
Further, when a plurality of oil seals are used to reduce the amount of leakage, the resistance to the rotating shaft increases, and heat generation and power increase occur.

On the other hand, the shaft seal that uses the mechanical seal has less leakage than the oil seal, but the leak cannot be completely eliminated, and the corrosive gas that drains into the lubricating oil that is present in the sliding contact surface of the mechanical seal. If it is mixed in, the lubricating oil will deteriorate and the durable life of the mechanical seal will be shortened.
In addition, the mechanical seal is extremely troublesome and time-consuming to assemble on the rotating shaft, which increases the manufacturing cost.

In view of such problems, it is a first object of the present invention to provide a roots blower provided with a shaft seal portion capable of extending the durable life of a bearing, a timing gear and a mechanical seal.
A second object of the present invention is to provide a roots blower provided with a shaft sealing portion capable of reducing manufacturing costs.

The invention according to claim 1
An oval rotor chamber having a pair of arcuate surfaces and a casing having a suction port that opens on one side of the intermediate surface of the rotor chamber and a discharge port that opens on the other side are rotated in opposite directions in the rotor chamber. A roots blower equipped with a pair of rotors, bearings that rotatably support the rotating shafts of each rotor on a casing, and a shaft seal on the rotating shafts that protrude outward from the rotor chamber.
Fix the housing to the casing so that it covers the rotating shaft that protrudes from the rotor chamber to the outside.
An intermediate chamber is formed inside the housing to collect drainage so as to surround the axis of rotation.
The shaft seal is composed of an oil seal and a mechanical seal, an oil seal is provided near the rotor chamber, a mechanical seal is provided on the outside of the oil seal, and the intermediate chamber is sealed with the oil seal and the mechanical seal.
An inert gas inlet and drain outlet that communicate with the intermediate chamber are formed in the housing.
A bearing and a lubricating oil cover are provided on the outside of the mechanical seal to store the lubricating oil.
During operation, the inert gas is introduced into the intermediate chamber through the inert gas inlet to pressurize or depressurize the intermediate chamber.
The mechanical seal is fitted to the rotation shaft with a spring-urged seal ring in a direction parallel to the rotation shaft, and a collar that presses the tip of the seal ring into contact with the rotation shaft outside the seal ring, and the collar is fixed to the rotation shaft. Consists of a set screw
It is characterized by providing a special jig for positioning the collar at the mounting position outside the predetermined mounting position of the collar and a space for mounting a set screw mounting tool.

The invention according to claim 2 is the invention according to claim 1 in the roots blower according to claim 1.
The dedicated jig has a cylindrical structure, and the inner surface is provided with a jig step portion that contacts the shaft step portion formed on the rotating shaft and a jig screw portion that is screwed into the shaft screw portion formed on the rotating shaft. Set the jig screw part to the shaft screw part, set the special jig on the rotating shaft, and screw the special jig until the jig step part comes into contact with the shaft step part to set the collar at the specified mounting position. It is characterized by that.

The invention according to claim 3 is the invention according to claim 1 in the roots blower according to claim 1.
The feature is that the bearing is stored in the bearing case and the bearing case is fixed to the housing with bolts.

According to the invention of claim 1, since the inert gas is introduced into the intermediate chamber sealed by the oil seal and the mechanical seal and pressurized, the drain accumulated in the intermediate chamber can be discharged to the outside of the housing from the drain discharge port. ..
Therefore, it is possible to prevent the drain from entering the bearing or the timing gear and mixing with the lubricating oil of the bearing or the timing gear to deteriorate the lubricating oil, so that the durable life of the bearing or the timing gear can be extended.

Since the oil seal that seals the intermediate chamber is provided near the rotor chamber, it is possible to prevent the inert gas introduced into the intermediate chamber from entering the rotor chamber and being mixed with the condensing gas or corrosive gas in the rotor chamber.
Further, if the pressure in the intermediate chamber is reduced to be lower than the pressure in the rotor chamber, the leakage of the inert gas to the rotor chamber can be suppressed as much as possible, and the lubricating oil leaking from the lubricating oil cover can be prevented from entering the rotor chamber. Can be prevented.

Since the mechanical seal can be assembled to the rotating shaft using a special jig, the mechanical seal assembly work can be carried out easily and quickly, and the manufacturing cost can be reduced.

According to the invention of claim 2 , since the collar of the mechanical seal can be set in a predetermined position by screwing the special jig into the rotating shaft, the mechanical seal assembling work can be carried out more easily and quickly, and the manufacturing cost can be reduced. It can be reduced.

According to the invention of claim 3 , since the bearing case containing the bearing is assembled to the housing with bolts, the space required for using a special jig or mounting tool can be secured, and the bearing assembly work is easy. It can be carried out quickly and the manufacturing cost can be reduced.

It is a partially broken front view which shows the roots blower which concerns on embodiment of this invention. It is sectional drawing cut from 2-2 line of FIG. It is sectional drawing which cut from the 3-3 line of FIG. It is sectional drawing which shows the internal structure of the housing of the roots blower. It is a partially enlarged sectional view which shows the mechanical seal of the roots blower. It is a partially enlarged sectional view which shows the special jig.

The present invention will be described below with reference to the drawings. FIG. 1, FIG. 2 and FIG. 3 show the roots blower 10 according to an embodiment of the present invention. As shown in FIG. 1, the roots blower 10 includes a casing 11 and a housing 12 fixed to both the left and right sides of the casing 11 and integrally with the casing 11.

As shown in FIG. 2, an oval rotor chamber 11a having a pair of arcuate surfaces inside the casing 11, a suction port 11b that opens on one side of the intermediate surface of the rotor chamber 11a, and a discharge port that opens on the other side. An outlet 11c is formed, and a discharge pipe 13 is connected to the discharge port 11c. A pair of rotors 14 that are rotated in opposite directions are stored in the rotor chamber 11a.

The rotating shaft 15 of the rotor 14 projects from the side surface of the casing 11 to the outside of the rotor chamber 11a, and the housing 12 is fixed to the casing 11 so as to cover the protruding rotating shaft 15. As shown in FIGS. 3 and 4, an intermediate chamber 12a for storing the drain 16 is formed inside the housing 12 so as to surround the rotating shaft 15. The intermediate chamber 12a is sealed by an oil seal 17 provided close to the rotor chamber 11a and a mechanical seal 18 provided on the outside of the oil seal 17, and the oil seal 17 and the mechanical seal 18 are used from the rotor chamber 11a of the rotating shaft 15. A shaft seal portion of a portion protruding to the outside is configured. Further, the housing 12 is formed with an inert gas introduction port 12b and a drain discharge port 12c communicating with the intermediate chamber 12a.

As shown enlarged in FIG. 5, the mechanical seal 18 is fitted to the seal ring 18b urged by the spring 18a in the direction parallel to the rotation shaft 15 and the rotation shaft 15 outside the seal ring 18b, and the seal ring is fitted. It is composed of a collar 18c to which the tip end portion of the 18b is in pressure contact and a set screw 18d for fixing the collar 18c to the rotating shaft 15. The collar 18c is fixed to the rotating shaft 15 by using a special cylindrical jig 19 and a mounting tool 20.

As shown in FIG. 6, the rotary shaft 15 is formed with a shaft step portion 15a and a shaft screw portion 15b outside a predetermined mounting position of the collar 18c. On the other hand, a jig step portion 19a and a jig screw portion 19b are formed on the inner surface of the dedicated jig 19.
The procedure for attaching the mechanical seal 18 is as follows.
The seal ring 18b is put on the rotating shaft 15 and stored in the recess 12d formed in the housing 12, and then the collar 18c is put on the rotating shaft 15, and then the special jig 19 is put on the rotating shaft 15 and the jig screw. When the portion 19b is screwed into the shaft screw portion 15b, the collar 18c is pushed inward by the tip portion of the special jig 19. Then, when the jig step portion 19a comes into contact with the shaft step portion 15a, the collar 18c is positioned at a predetermined mounting position. Therefore, the set screw 18d is screwed with the mounting tool 20 to fix the collar 18c to the rotating shaft 15. ..

A bearing 21 that rotatably supports the rotating shaft 15 to the casing 11 is provided on the outside of the mechanical seal 18. The bearing 21 is fitted to the inner peripheral surface of the cylindrical bearing case 21a, and the bearing case 21a is fixed to the housing 12 with bolts 22. A bearing nut 23 is screwed to the rotating shaft 15.
By using the bearing case 21a in this way, the special jig 19 is set on the rotating shaft 15, and the space required for using the mounting tool 20 is secured on the outside of the mechanical seal 18.

A timing gear 24 is attached to the rotating shaft 15, a lubricating oil cover 25 is attached to the housing 12 so as to cover the timing gear 24, and lubricating oil is stored inside the lubricating oil cover 25.

The structure of the roots blower 10 according to this embodiment is as described above. When the rotor 14 is rotated by a drive motor (not shown), a fluid containing a condensing gas or a corrosive gas flows from the suction port 11b to the rotor chamber 11a. Is sucked into the rotor chamber 11a, compressed in the rotor chamber 11a, and discharged from the discharge pipe 13.
Therefore, according to this embodiment, the drain 16 accumulated in the intermediate chamber 12a is formed by introducing nitrogen gas or an inert gas such as air into the intermediate chamber 12a sealed by the oil seal 17 and the mechanical seal 18 and pressurizing the mixture. Can be discharged to the outside of the housing 12 from the drain discharge port 12c. Therefore, it is possible to prevent the drain 16 from invading the bearing 21 and the timing gear 24 and mixing with the lubricating oil of the bearing 21 and the timing gear 24 to deteriorate the lubricating oil, so that the durable life of the bearing 21 and the timing gear 24 can be extended. Can be stretched.

Since the oil seal 17 for sealing the intermediate chamber 12a is provided near the rotor chamber 11a, the inert gas introduced into the intermediate chamber 12a invades the rotor chamber 11a and is mixed with the condensing gas and the corrosive gas in the rotor chamber 11a. Can be prevented from doing so.
Furthermore, if the intermediate chamber 12a is depressurized to be lower than the pressure of the rotor chamber 11a, the leakage of the inert gas to the rotor chamber 11a can be suppressed as much as possible, and the lubricating oil leaking from the lubricating oil cover 25 can be discharged to the rotor chamber. It is possible to prevent the invasion of 11a.

Since the mechanical seal 18 can be assembled to the rotating shaft 15 using the special jig 19, the mechanical seal 78 can be assembled easily and quickly, and the manufacturing cost can be reduced.

Since the bearing case 21a to which the bearing 21 is fitted is assembled to the housing 12 with the bolt 22, the space required for using the special jig 19 and the mounting tool 20 can be secured, and the bearing 21 assembly work is easily and quickly performed. It is possible to reduce the manufacturing cost.

10 ... Roots blower 11 ... Casing 11a ... Rotor chamber 11b ... Suction port 11c ... Discharge port 12 ... Housing 12a ... Intermediate chamber 12b ... Inactivated gas introduction port 12c ... Drain discharge port 14 ... Rotor 15 ... Rotating shaft 15a ... Shaft stage 15b ... Shaft screw part 16 ... Drain 17 ... Oil seal 18 ... Mechanical seal 18a ... Seal ring 18b ... Color 18c ... Set screw 19 ... Dedicated jig 19a ... Jig step part 19b ... Jig screw part 20 ... Mounting tool 21 ... Bearing 21a ... Bearing case 22 ... Bolt 24 ... Timing gear 25 ... Lubricating oil cover

Claims (3)

An oval rotor chamber having a pair of arcuate surfaces and a casing having a suction port that opens on one side of the intermediate surface of the rotor chamber and a discharge port that opens on the other side are rotated in opposite directions in the rotor chamber. A roots blower equipped with a pair of rotors, bearings that rotatably support the rotating shafts of each rotor on a casing, and a shaft seal on the rotating shafts that protrude outward from the rotor chamber.
Fix the housing to the casing so that it covers the rotating shaft that protrudes from the rotor chamber to the outside.
An intermediate chamber is formed inside the housing to collect drainage so as to surround the axis of rotation.
The shaft seal is composed of an oil seal and a mechanical seal, an oil seal is provided near the rotor chamber, a mechanical seal is provided on the outside of the oil seal, and the intermediate chamber is sealed with the oil seal and the mechanical seal.
An inert gas inlet and drain outlet that communicate with the intermediate chamber are formed in the housing.
A bearing and a lubricating oil cover are provided on the outside of the mechanical seal to store the lubricating oil.
During operation, the inert gas is introduced into the intermediate chamber through the inert gas inlet to pressurize or depressurize the intermediate chamber.
The mechanical seal is fitted to the rotation shaft with a spring-urged seal ring in a direction parallel to the rotation shaft, and a collar that presses the tip of the seal ring into contact with the rotation shaft outside the seal ring, and the collar is fixed to the rotation shaft. Consists of a set screw
A roots blower characterized by providing a special jig for positioning the collar at the mounting position outside the predetermined mounting position of the collar and a space for the mounting tool of the set screw . The dedicated jig has a cylindrical structure, and the inner surface is provided with a jig step portion that contacts the shaft step portion formed on the rotating shaft and a jig screw portion that is screwed into the shaft screw portion formed on the rotating shaft. Set the jig screw part to the shaft screw part, set the special jig on the rotating shaft, and screw the special jig until the jig step part comes into contact with the shaft step part to set the collar at the specified mounting position. The roots blower according to claim 1. The roots blower according to claim 1, wherein the bearing is housed in a bearing case, and the bearing case is fixed to the housing with bolts.

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