JPS62233492A - Oil rotating vacuum pump - Google Patents

Abstract

PURPOSE:To contrive to reduce power by providing a control valve which opens only when vacuum degree reached a value nearer to the vacuum than the set value, in a rearer stage part than the intermediate exhaust valve in the intermediate exhaust passage of a double pump. CONSTITUTION:An oil rotating vacuum pump 1 is constituted of front/rear stage pump main bodies 3, 6 and therein an exhaust port 18 on the exhaust side B and a suction port 19 on the suction side C are communicated with each other through an intermediate exhaust passage 21. A control valve 25, which opens only when the vacuum degree by the operation of a pump 1 reached a value nearer to the vacuum than the set value, is provided in the rearer stage side than an intermediate exhaust valve 24 in the intermediate exhaust passage 21. Accordingly the full power to be supplied can be effectively reduced without lowering the reached vacuum degree.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention can be widely used in various fields using vacuum equipment.
This invention relates to a dual-barreled oil rotary vacuum pump.

L Conventional Techniques &] For example, when it is necessary to achieve an ultimate vacuum of about 1O-5, it is common to use a dual oil rotary vacuum pump.

However, the conventional double-barreled oil rotary vacuum pump.

A front-stage pump body having a rotor with vanes housed eccentrically within a casing and a rear-stage pump body having the same structure are housed in an oil tank for rhythmic operation,
The i! I have sent one. Then, the intake port of the front-stage pump body is communicated with the intake pipe connected to a vacuum chamber, etc., and the intermediate exhaust valve and the rear-stage exhaust valve provided at the exhaust port part of the vkC+ side pump body are connected to the space in the oil tank. It communicates with the exhaust port through.

It is common knowledge that such dual oil rotary α-air pumps are designed so that the sum of the theoretical compression power of the front-stage pump body and the theoretical compression power of the rear-stage pump body is minimized. As a result, the exhaust volume ratio between the tnin side pump body and the rear stage pump body is generally determined to be approximately 1 to 5:1.

Problems to be Solved by the Invention] However, in this type of vacuum pump, in order to not only improve lubrication and sealing performance, but also to fill the dead volume in the pump chamber and improve exhaust characteristics,
The oil in the oil tank is sequentially introduced into each pump body, and the oil is circulated while being energized by vanes while being exhausted. Therefore, in order to operate this oil rotary vacuum pump, it is necessary to use not only the compression power to compress and discharge the gas introduced from the intake port, but also the power for the oil pressure force to energize and circulate the oil. It is also necessary to supply it in addition. The power for this oil pump greatly increases to 1111 as the pump body's exhaust volume increases, and dual oil rotary vacuum pumps perform exhaustion with only a single pump body. The proportion of power used by the Aburamura forces is extremely large compared to that of the
It fluctuates depending on the change in the viscosity of the oil. Therefore, a large amount of power is required to start the engine in winter when the oil is thick and viscous. Therefore, if a drive electric motor is selected in response to this situation, it will be very large.
There will be more waste. On the contrary, like this! If you select an electric motor without taking this into account, the engine will repeat startup and stop due to thermal relay disconnection during cold start, and will continue to operate normally until the oil temperature reaches t'i4. There will be a problem of not being able to do this.

The present invention aims to solve the following problems.

[1^1 Means for Solving Problems] In order to achieve the above object, the present invention provides a double-barreled oil rotary vacuum pump as described above.

The present invention is characterized in that a control valve that opens only when the degree of vacuum reaches a value closer to vacuum than a set value is provided in a portion of the intermediate exhaust path downstream of the intermediate exhaust valve.

1 Effect 1 According to such a configuration, until the degree of vacuum reaches the set value, the control valve closes and the intermediate exhaust path is closed, so 1 The original α air exhaust work is performed only by the front pump body. . When the degree of vacuum reaches a point closer to vacuum than the set point, the control valve opens, and the exhaust port of the front-stage pump body and the intake port of the rear-stage pump body communicate via the intermediate exhaust path. I will do it. As a result, the pressure at the exhaust port portion of the front-stage pump body is lowered by the evacuation action of the rear-stage pump body, and the differential pressure across the front-stage pump body decreases. Therefore, the pressure on the intake port side of this front-stage pump main body can be guided even further to 44, which is closer to vacuum.

However, this method uses only the mechanism of the front-stage pump body to perform α air exhaust as much as possible, and only when the exhaust power of the front-stage pump body approaches its limit, the rear-stage pump body It is also used auxiliary. Therefore, from the initial role of exhaust, the rear pump body is also raised to a peak, and the pressure of the front pump body is reduced. By reducing the liI power.

1. To reduce the total compression power as much as possible.
The exhaust volumes H and I of the downstream pump body can be made much smaller than those designed with one standard. Therefore, it cannot be denied that the sum of the compression power of the front-stage pump body and the compression power of the VK retraction-side pump body is slightly larger than that of the conventional pump body.

By reducing the exhaust capacity of the latter-stage pump body, it is possible to significantly reduce the power for the above-mentioned Yumura force with the 4J, and the total power for driving is lower than that of the conventional 4J. can also be reduced.

[Example J An embodiment of the present invention will now be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the configuration of an oil rotary vacuum pump according to the present invention.

The oil rotary empty pump l is the oil tank z that stores oil on a predetermined floor.
It is a two-stage pump in which a front-stage pump main body 3 and a rear-stage pump main body 6 are disposed, each of which performs an exhaust function. Each of these pump bodies 3.6 has a cylindrical casing 4, 5, respectively.
A rotor 9.11 with a vane 7.8 is housed in an eccentric position within the casing 4.5, and a vane 7.8 is partitioned between each of these casings 4.5 and the rotors 9, 11. As the rotating rotor 91 rotates, I! A front-stage pump chamber 12 and a rear-stage pump chamber 13 in which rust changes are formed. The capacity of the pump chamber 13 on the 16th stage side is approximately 1/20th that of the pump chamber 12 on the previous stage side.

One end of each of the rotors 9.11 on the discharge contact side is connected by a rotating shaft 15 that is freely rotatably supported by the intermediate 1 (center 14) that connects both the casings 4.5.
Further, one end of an input shaft 16 for transmitting power from a power source is fixedly attached to the other end of the rotor 9 on the front stage side.

Further, the inner end of the intake pipe 17 is connected to an intake bow 10 provided on the intake side A of the front pump chamber 12. This suction pipe 17 is connected to a vacuum chamber or the like, and its outer end projects outside the pump.

Furthermore, the exhaust port 18 provided on the exhaust side B of the former pump chamber 12 and the intake port 19 provided on the intake side C of the latter pump chamber 13 are connected via the intermediate exhaust path 21 to i1! I'm letting it pass. An intermediate exhaust port 23 that opens the exhaust port 18 of the front pump chamber 12 into the space 22 in the oil tank z is provided at the starting end of the intermediate exhaust path 21, and an intermediate exhaust valve 24 is provided at the opening end surface of the intermediate exhaust port 23. It is being

Then, the valve is opened only when the degree of vacuum caused by the operation of the oil rotary vacuum pump l on the downstream side of the intermediate exhaust valve 24 of the intermediate exhaust path 21 reaches a value closer to vacuum than the set value (for example, 1 Tall). Control j? Barrel 1 magnetic valve 25
are intervening. Namely.

The solenoid valve 25 is connected to the exhaust port 18 of the front pump body 3.
i! and the intake port 19 of the rear pump body 6! 1! It is controlled by a control circuit 26. The control circuit 26 controls the air intake of the front pump main body 3! ?
The signal from the pressure sensor 26a that detects the degree of vacuum inside the electromagnetic 5p2 is compared with a preset value, and if the detected degree of vacuum is less than the setting fti, the electromagnetic 5p2
The electromagnetic valve 25 is configured to output a signal to open the electromagnetic valve 25, while outputting a signal to close the electromagnetic valve 25 when the value is less than a set value.

In addition, an exhaust port 27 is provided on the exhaust side of the rear-stage pump 'l 13, and this exhaust port 27 is connected to the rear-stage exhaust valve 28.
iI! to the space 22 in the oil tank 2 via the iI! Furthermore, the space 22 has an exhaust port 2 opened at the end of the oil tank 2.
9 to open to the outside.

With such a configuration, when the human power shaft 16 is driven by an electric motor or the like, the rotors 9 and 11 with vanes 7.8 rotate to carry out an exhaust action, and the vacuum nayan bar connected to the intake pipe 17 is However, in the region where the degree of vacuum in the intake IrF 17 is less than the set value (l Toll), the exhaust port 18 of the 1uI stage side pump chamber 12 and the intake port 19 of the rear stage side pump chamber 13 are i! l! Since the connecting φ exhaust path 21 is blocked by the electric current m:1P25, all the gas discharged from the pump chamber 12 on the first bend side is directly discharged into the space 22 in the oil tank 2 via the intermediate exhaust valve p24. That is, in this region, exhaust is performed only by the front pump body 3. on the other hand.

+iii 1. in the intake pipe 17. When the IL emptyness is set (I'+6 below It, the 'ilj magnetic valve 25 opens and some or all of the gas discharged from the front pump chamber 12 is discharged to the rear pump chamber 13. In this region, exhaust work is performed by the two pump bodies 3.4.The pressure at the exhaust port 18 portion of the front pump body 3 is reduced by the exhaust action of chamber a by the rear pump body 6. As a result, the differential pressure across the front pump body 3 decreases.Therefore, the pressure on the intake port IO side of the front pump body 3 can be brought to a value closer to vacuum, for example, to a value closer to 10-5. I can do it.

However, as described in 1.2 above, this system uses only Ia of the front pump body 3 to perform vacuum evacuation as much as possible, and only when the exhaust capacity of the front pump body 3 approaches its limit, The latter pump main body 6 is also used auxiliary. Therefore, compared to those designed with the goal of reducing the total compression power as much as possible by aTEing the rear pump body from the initial stage of exhaust and reducing the compression power of the front pump body. The exhaust capacity of the downstream pump body 6 can be made much smaller. That is, as described above, the exhaust container of the rear pump body 6 is
Even if it is set to about 20/l of the air pressure needle.

The ultimate vacuum 1" can be obtained at the same level as the conventional one. Therefore, the sum of the compression power of the front-stage pump body 3 and the compression power of the rear-stage pump body 6 is:

Although it is undeniable that it is slightly larger than the conventional one, the water-oil rotary vacuum pump 1 can significantly reduce the power for the above-mentioned oil pump by reducing the exhaust capacity of the rear pump body 6. Therefore, the total driving power can be reduced compared to the conventional one.

Moreover, by downsizing the pump body 6 on the rear stage side, not only will it be easier to make the entire pump more compact, but it will also be possible to reduce dead space and improve efficiency, reducing the amount of oil needed. : It can also reduce noise and reduce noise.

The control valve is of course not limited to the magnetic type, and may be configured to operate using the α air pressure of the exhaust system as pilot pressure.

In addition, it goes without saying that the exhaust capacity of the rear pump body is not limited to 20/1 of the exhaust capacity of the front pump body, and the ultimate vacuum level may be lowered by changing the sealing properties, etc. It is also possible to further downsize the rear pump body.For example, if the rear pump body is further downsized, the vane may be held directly on the rotating shaft extending from the front pump body. The rotating shaft itself can also be used as the rotor of the 1g pump body.

E Effects of the invention j Since the present invention has the following configuration, it is possible to effectively reduce the total power to be supplied without lowering the ultimate vacuum degree, and moreover, it is possible to reduce the overall size. It is possible to provide an epoch-making oil rotary vacuum pump that can reduce the amount of oil 51) and suppress the adverse effects caused by changes in oil viscosity, and can also achieve low noise FkJ. It is.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an oil rotary V↓air pump showing one embodiment of the present invention, and FIG. 2 is a schematic circuit diagram of the same embodiment. l... Oil rotary α empty pump 2... Oil tank 3... Front side pump body 6... Back side pump body 18... Exhaust port 19... Intake port 21
...Intermediate exhaust path 24...Intermediate exhaust valve 25...
Park magnetic valve (control valve)

Claims (1)

[Claims] A two-barreled oil rotary vacuum pump in which an exhaust port of a front-stage pump body and an intake port of a rear-stage pump body are communicated via an intermediate exhaust route having an intermediate exhaust valve, the intermediate exhaust route having a An oil rotary vacuum pump characterized in that a control valve that opens only when the degree of vacuum reaches a value closer to vacuum than a set value is provided at a stage downstream of the intermediate exhaust valve.