KR20160072962A - Roots pump having improved structure - Google Patents

Abstract

The present invention prevents an exhaust speed of a roots pump from being reduced, and solves a problem with respect to reduction of an exhaust speed due to a post-pump by improving a structure to maintain an exhaust speed of a roots pump to be always constant. To achieve this, a roots pump having a cylinder and a pair of rotors comprises: a bypass discharge path provided at one side of the cylinder; a first exhaust valve exhaust port provided in an upper portion of one side of the cylinder; a valve seat arranged between the bypass discharge path and the exhaust port; and a first exhaust valve formed by being placed on the valve seat.

Description

Root pump having improved structure < RTI ID = 0.0 >

The present invention relates to a roots pump having an improved structure in which a rear-end pump is continuously connected and operated so that residual gas that can not be processed in a rear-end valve can be discharged to the outside.

The Roots vacuum pump is also called a booster vacuum pump, which is used in conjunction with a backing pump, such as a wet vacuum pump and a dry vacuum pump.

1. Typical Roots Vacuum Pump

The exhaust velocity and the degree of vacuum of the Roots vacuum pump are determined according to the exhaust characteristics of the rear stage pump. Generally, the lower the arrival pressure of the downstream pump and the faster the exhaust velocity, the lower the ultimate pressure of the Roots vacuum pump and the faster the exhaust velocity. A typical Roots pump is designed to operate when the pressure at the exhaust is about 10 Torr.

The Roots vacuum pump, which has a large exhaust speed, is used to shorten the working time. The Roots pump does not operate until the pressure of the vacuum container is lowered to about 10 Torr at the rear stage pump connected with the Roots pump, The Roots pump is activated, so that the effect of shortening the working time is not significant.

When the exhaust port of the Roots pump and the suction port of the rear pump are directly connected, the rear stage pump is operated first to suck and exhaust the process gas of the vacuum container. In the case of the Roots pump connected directly, And the pump is sucked into the rear stage pump. Thus, the rotor of the Roots pump interferes with the movement of the process gas, and the operation time is required to be reduced to 10 Torr from the rear stage pump.

In order to solve this problem, the piping connected to the inlet of the roots pump between the two pumps connected directly to each other bypasses the roots pump and connects to the suction port of the rear stage pump to solve the problem that the rotor of the roots pump obstructs the movement of the gas However, this requires piping bypassing the roots pump and the rear stage pump, which increases the equipment cost.

In addition, there is a problem that the Roots vacuum pump is not used to achieve a satisfactory effect for shortening the working time and the facility cost is increased.

2. Bypass valve-type roots vacuum pump

In order to solve the problem that is a problem of the conventional type Roots vacuum pump, the operation of the Roots vacuum pump is changed from the atmospheric pressure (760 Torr) to the rear end (760 Torr) in order to shorten the time taken until the rear- It is also called an atmospheric pressure pump because it improves the structure to shorten the work process time by operating the roots vacuum pump at the same time as the pump.

5) of the conventional bypass valve-type roots vacuum pump simultaneously operates the roots pump connected to the rear stage pump at atmospheric pressure so that when the roots pump motor rotates, the main-shaft rotor 7 rotates and the main- The two motors 7 and 8 are rotated so that the process gas is sucked through the suction port 9 and is transferred to the exhaust port 10 to be connected to the exhaust port 10 The connected rear stage pump sucks and exhausts.

Since the exhaust speed of the Roots pump is about 5 to 10 times larger than the exhaust speed of the rear pump connected to the Roots vacuum pump, if the two pumps are simultaneously operated at atmospheric pressure, the process gas sucked and exhausted from the Roots pump is discharged from the rear stage pump And the remaining process gas is compressed in the inlet port of the roots pump and the inlet port of the rear pump connected to the two pumps. In the case of the conventional type roots pump, the amount of gas that is not processed in the space connected to the rear stage pump is gradually increased to increase the amount of roots pump, so that the rotor needs to rotate with a larger force. This causes the rotor of the Roots pump to become damaged, causing damage to the rotors, gears, and bearing sealing parts.

As a method for solving the problem caused by the compressed gas in the space between the roots pump and the rear stage pump, as shown in Fig. 5, the exhaust port 10 and the suction port 9 of the pump are connected to the outer wall adjacent to the cylinder 1 The gas remaining in the passage 11 without being processed in the rear stage pump which finally makes the gas and compresses the gas to be discharged into the atmosphere, that is, the gas which is connected to the exhaust port 10 The residual gas that has not been discharged due to the inhalation process in the rear stage pump is compressed around the exhaust port 10 of the roots pump and moves along the exhaust circulation passage 11 to circulate to the suction circulation passage 12 and then to the rotor 7 The valve seat (12) having the circulation hole (13) between the exhaust circulation passage (11) and the suction circulation passage (12) 13a, System 28, 29, are improved due to the compressed residual gas problem by improving a structure to open and close the circular hole 13 of the valve seat (13a) (30).

That is, according to the above-described bypass valve system 28, 29, 30, when the rear stage pump connected to the roots pump simultaneously operates at atmospheric pressure, the compressed gas, which can not be processed by the rear stage pump, flows into the exhaust circulation passage 11 And the compressed gas is supplied to the bypass valve 28 which is supported by the spring 29 that has closed the circulation hole 13 in a compressed state in the compressed space 11 And is then transferred to the space of the suction / circulation passage 12, and is then transferred to the exhaust port again by the rotors 7 and 8 which are performing the suction motion work so as to be circulated continuously, To solve the problems and shorten the work process time.

However, in the above-mentioned conventional system, the roots pump is sucked from the vacuum equipment and transferred to the rear stage pump in the process of sucking and exhausting the gas by simultaneously operating the atmospheric pressure gas at the initial stage of the pump operation and the rear stage pump connected to the roots pump, And the compressed gas which has not been exhausted from the exhaust gas is continuously circulated in the roots pump and then exhausted through the compression process. Compared with the conventional roots pump (Roots pump without circulation process of residual gas) In this method, however, the gas normally sucked through the suction port in the vacuum equipment and the compressed residual air circulated continuously in the roots pump are supplied to the rear stage Since the pump must be sucked and compressed and exhausted, Group rates are known to be improved from the point mothada not very effective work time away from the exhaust efficiency under the influence downstream pump exhaust speed is large. In addition, when overload is generated in the exhaust suction passage space at the end face of the circulation hole 13 in which the bypass valve 28 is closed when the compressed air is circulated in the roots pump, the motor is broken, There is a problem that is damaged. This problem is a problem that needs to be solved by the Roots pump.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. It is an object of the present invention to provide an apparatus and a method for operating the atmospheric-pressure roots pump and the rear- And it is an object of the present invention to provide an improved roots pump for solving the problem that excessive compression is generated in exhaust and suction circulation passages through which compressed air is circulated and thereby the motor and parts are damaged.

Another object of the present invention is to prevent the exhaust speed of the Roots pump from being reduced due to the influence of the exhaust speed of the relatively small rear pump when the Roots pump is used in connection with the rear stage pump and to keep the exhaust speed of the Roots pump constant And the problem of reducing the exhaust speed due to the rear stage pump is solved.

In order to achieve the above-mentioned object, the present invention provides a vacuum cleaner comprising: a cylinder having a suction port connected to a vacuum equipment side and an exhaust port connected to a rear stage pump side; A bypass exhaust passage provided at one side of the cylinder to communicate with the exhaust port side, and a bypass exhaust passage provided at one side of the cylinder so as to communicate with the exhaust port side; A primary exhaust valve exhaust port provided at an upper portion of one side of the cylinder to communicate with the bypass exhaust passage; A tapered valve seat provided between the bypass discharge passage and the exhaust port to face the upper surface of the valve seat; The valve seat is brought into close contact with the valve seat by its own weight to close the external discharge hole formed in the valve seat and is lifted from the valve seat by the gas pressure remaining in the bypass discharge passage, And a primary exhaust valve formed by a ball.

According to a preferred embodiment of the present invention, the valve seat having the primary exhaust valve exhaust port and the external exhaust port is formed in a primary exhaust valve body, which is a separate body, and the primary exhaust valve body is assembled .

In the present invention, when exhaust gas through the exhaust port (10) is insufficient and residual gas is generated in the bypass exhaust passage (11) more than a reference value, the primary exhaust valve (15) is opened again to discharge the gas to the outside. The first exhaust valve 15 in the primary exhaust valve body 17 is opened and exhausted by the gas pressure when there is a compressed process gas that can not be processed by the rear stage pump, The speed of the bypass exhaust passage 11 can be maintained. Accordingly, the problem of damages due to overload of the motor caused by compression of the gases in the bypass exhaust passage 11 and damage to the components can be solved, The work process time can be shortened and the working time for vacuuming can be shortened.

In addition, since the metal ball valve according to its own weight is used and the valve seat is made into a tapered shape which is opposed to the upper surface of the valve seat, only the ball valve is received in the primary exhaust valve body to complete the assembly. Further, It can also be assembled to a cylinder, making it easy to manufacture and assemble.

1 is a plan sectional view of a Roots pump (AA sectional view in Fig. 2) according to the present invention.
Fig. 2 is a side sectional view (sectional view taken along the line BB in Fig. 1) of the roots pump according to the present invention, showing a state in which the primary exhaust valve systems 14, 15 and 17 are assembled into a single pump assembly .
3 is a cross-sectional view of a roots pump according to the present invention in which a primary exhaust valve system 16, 17 is integrally formed in a pump cylinder and a primary exhaust valve 15 is assembled.
4 (a) and 4 (b) are views for explaining the operating state of the roots pump according to the present invention.
5 is a view showing a structure of a conventional bypass valve type roof pump.

In the following detailed description, reference is made to the accompanying drawings which show, by way of illustration, specific embodiments in which the invention may be practiced.

These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are not necessarily mutually exclusive, even if different. By way of example, certain aspects, structures, or features described herein in connection with one embodiment may be practiced by other embodiments without departing from the spirit and scope of the invention.

It is also to be understood that the position or arrangement of individual elements within each disclosed embodiment may be modified without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims appropriately interpreted and by the full range of equivalents to which such claims pertain. In the drawings, like reference numerals refer to the same or similar functions in the various figures.

Fig. 1 is a sectional front view of a roots pump according to the present invention. The roots pump has a cylinder 1. A pair of rotors (a main shaft rotor 7 and a driven rotor 8) And a gear side plate 2 and a motor side plate 4 are mounted on both sides of the cylinder 1 and the rotor shafts 7a and 8a of the rotors 7 and 8 are supported by bearing And is rotatably supported by the gear and motor side plates (2, 4) via a pair of gears (20, 22).

The gear casing 3 and the front plate 5 are mounted on both sides of the plates 2 and 4. The gear casing 3 is provided with a rotor shaft 3 projecting to one side of the gear side plate 2, A main shaft helical gear 18 and a driven shaft helical gear 19 which are fixedly mounted on the ends of the helical gears 7a and 8a are housed in the housing 1. The helical gears 18 and 19 are engaged with each other, And rotates at a rotational speed.

A pump coupling 24 and a motor coupling 25 are connected to each other at an end portion of the rotor shaft 7a which protrudes through the front plate 5 and is connected to the coupling coupling 24, A motor flange 6 is mounted on the side surface of the platen 5 so as to protect the motor flange 6. A motor 27 is mounted on the outside of the motor flange 6, (25) and drives the rotor shaft (7A) to rotate.

2, a first exhaust valve exhaust port 16, which is opened to the outside, is formed at an upper portion of one side of the cylinder 1, that is, the right upper portion in the illustrated embodiment, The primary exhaust valve body 17 having the exhaust port passage 14 and the tapered valve seat 13 gradually becoming narrower toward the lower portion is formed as a separate body from the cylinder 1 and assembled to the cylinder 1 And a primary exhaust valve 15 formed of a metal ball valve 15 is accommodated in the primary exhaust valve body 17. This primary exhaust valve 15 (metal ball valve) And is brought into close contact with the inner surface of the tapered valve seat 13 to shut off the communication between the exhaust port passage 14 and the primary valve exhaust port 16, When it acts on the path passage 11, the valve seat 13 is lifted to open the valve seat 13 It is configured to discharge the remaining compressed gas in the by-pass passage 11 to the outside.

As shown in FIG. 2, a pump inlet 9 is formed in the upper part of the substantially central portion of the cylinder 1, and an exhaust port 10 is provided in a lower portion of the cylinder 1 opposite to the pump inlet 9, (Not shown) through a duct and a gas exhausted through the exhaust port 10 is sucked and compressed by a rear stage pump to finally discharge the exhaust gas to the outside. The bypass passage 11 is formed toward one side of the primary exhaust valve body 17 at one side of the cylinder 1 and is connected to the intake port 9 through the intake port 9, (12) for diffusing the refrigerant gas into the entire cylinder (1).

3 is a modified embodiment of the present invention. In the case of FIG. 2, the primary exhaust valve body 17 having the primary valve exhaust port 16 is formed into a powder and assembled to the cylinder body, Is integrally cast on the body of the cylinder (1). In the case of the single body, the number of parts and the assembling process are reduced. On the other hand, the casting failure rate may be high due to difficulty in molding due to the complicated casting, and the primary exhaust valve body 17 It is a practical matter to assemble to the cylinder (1) body separately.

Here, reference numerals 21 and 23 denote bearing covers for protecting bearings, and reference numeral 26 is a lip seal housing for imparting sealing property.

Hereinafter, the operation of the present invention will be described with reference to Figs. 5 (a) and 5 (b).

When the motor 27 starts driving, the gas is drawn out to vacuum the unillustrated vacuum equipment. At this time, when the rotor shaft 7a rotates in the normal direction by the motor 27, the pair of gears 18 The rotor shaft 8a engaged with the pair of rotors 7 and 8 starts to rotate in the opposite direction, so that the pair of rotors 7 and 8 start to rotate in the engaged state.

When the rotors 7 and 8 are rotated, the space 31 begins to expand and forms a vacuum negative pressure so that the gas on the vacuum equipment side is sucked into the space 31 through the suction port 9, (Refer to P in Fig. 4 (b)), the space 31 forms a space 32 that is disconnected from the side of the intake port 9. In this state, The gas trapped in the space 32 is forced to move toward the exhaust port 10 by being compressed by the movement of the space 32 so that the gas is exhausted while the space 32 is opened to the exhaust port 10 side, Gas is sucked to the rear stage pump side connected to the exhaust port 10, and then is exhausted to the atmosphere through a compression exhaust process by the rear stage pump.

However, when the amount of gas exhausted from the rotor pump directly connected to the vacuum equipment of the present invention is larger than the amount of gas discharged from the rear stage pump to the atmosphere in the pump drive, the amount of gas exhausted through the exhaust port 10 can not be transferred to the rear stage pump, This residual gas is discharged to the outside of the bypass exhaust passage 11 in such a manner that the degree of compression of the air remaining in the bypass exhaust passage 11 in the course of filling the bypass exhaust passage 11 is smaller than the self weight of the primary exhaust valve 15 The primary exhaust valve 15 can not be raised from the valve seat 13 due to the gas pressure so that the external exhaust hole 14 is closed. In such a case, the rotor 7 (8) It does not affect the level of the device does not give a load.

However, when the compressive force of the gas remaining in the bypass discharge passage 11 becomes higher than the reference value, the rotor 7 or 8 starts to be overloaded, and this reference value is determined based on the self weight of the primary exhaust valve 15, When the compressive force of the gas remaining in the bypass discharge passage 11 becomes larger than the weight thereof, the primary exhaust valve 15 is opened by the gas pressure pushing up the primary exhaust valve 15 at this time, When the primary exhaust valve 15 floats and is separated from the valve seat 13 to open the external exhaust hole 14, the bypass exhaust passage 11 Is exhausted to the atmosphere through the primary exhaust valve exhaust port 16 via the external exhaust hole 14 where the compressed gas remaining in the bypass exhaust passage 11 is lowered. When the pressure of the bypass exhaust passage 11 is lowered by this operation , The primary exhaust valve 15, which has been lifted, descends and comes into close contact with the valve seat 13 The gas sucked in the vacuum equipment according to the rotation operation of the rotors 7 and 8 is normally transferred to the rear stage pump side through the exhaust port 10 and the exhaust gas through the exhaust port 10 If the residual gas in the bypass discharge passage 11 is insufficiently generated, the primary exhaust valve 15 is opened again to exhaust the gas, so that the compressed process gas that has not been treated in the rear stage pump connected to the Roots pump The primary exhaust valve 15 in the primary exhaust valve body 17 is opened and exhausted, so that the design exhaust speed can be maintained regardless of the exhaust speed of the rear-stage pump.

As described above, since the primary exhaust valve 15 is installed in the roots pump, the problem that the motors and components generated by compressing the gases in the bypass exhaust passage 11 are damaged is solved, and the design exhaust speed To reduce the work process time and reduce the working time by using a roots pump having a large exhaust speed for the purpose of using the roots pump.

The above-described embodiments are merely illustrative of the technical structure of the present invention, and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to exemplary embodiments thereof, it is to be understood that such detailing embodiments of the invention may be modified by those skilled in the art and that part of the technical features may be modified without departing from the spirit of the invention, And such subject matter should be included within the scope of the technical method of the invention claimed below.

1.: Cylinder 2.: Gear side plate
3.: Gear casing 4.: Motor side plate
5.: Front plate 6.: Motor flange
7.: Spindle rotor 8.: Follower rotor
9. Inlet port 10.: Exhaust port
11.: Bypass discharge passage 12.: Suction circulation passage
13.: Valve seat 14.: Outlet hole
15.: Primary exhaust valve 16.: Primary exhaust valve exhaust
17.: Primary exhaust valve body 18.: Spindle helical gear
19.: Slave axis helical gear 20.: Bearing
21.: Bearing cover 22.: Bearing
23.: Bearing cover 24.: Pump coupling
25.: Motor coupling 26.: Lip seal housing
27. Motor

Claims (2)

A cylinder having a suction port connected to the vacuum equipment side and an exhaust port connected to the rear stage pump side and a pair of pumps for compressing the gas flowing in the cylinder and rotating on the suction port side for forced discharge to the rear stage pump side through the exhaust port A bypass discharge passage provided at one side of the cylinder so as to communicate with the exhaust port side; A primary exhaust valve exhaust port provided at an upper portion of one side of the cylinder to communicate with the bypass exhaust passage; A tapered valve seat provided between the bypass discharge passage and the exhaust port to face the upper surface of the valve seat; The valve seat is brought into close contact with the valve seat by its own weight to close the external discharge hole formed in the valve seat and is lifted from the valve seat by the gas pressure remaining in the bypass discharge passage, And a primary exhaust valve formed of a ball. The exhaust valve of claim 1, wherein the valve seat having the primary exhaust valve exhaust port and the external exhaust port is formed in a primary exhaust valve body as a separate body, and the primary exhaust valve body is assembled and mounted to the cylinder Roots pump with improved structure.

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