JP2695025B2 - Vacuum pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vacuum pump.

(Prior art) Conventionally, as a pump having a vacuum pump function, JIS
・ There is a water-sealed vacuum pump as described in B8323. In this water-sealed vacuum pump, makeup water is supplied into a casing, and an impeller rotates inside the casing to suck air from a suction port and release the air into the atmosphere.

However, when the degree of vacuum used approaches the saturated vapor pressure of the make-up water temperature, this conventional water-sealed vacuum pump generates severe noise due to cavitation and becomes unusable. As a solution to this problem, an air ejector is placed in front of a water-sealed vacuum pump to avoid noise.

(Problems to be Solved by the Invention) As described above, in the conventional pump, when the vacuum pump function is obtained, there is a problem that noise is generated due to cavitation, and an air ejector is provided in the front stage of the pump, and the water sealing type is used. The structure of the vacuum pump becomes complicated. Further, since it is necessary to install an air ejector or the like in front of the pump, the price becomes high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vacuum pump capable of quiet operation up to a high vacuum level without requiring an air ejector or the like.

(Means for Solving the Problem) The invention according to claim 1 has a casing having an annular blade fitting groove and an annular pressure-increasing passage on the outer periphery of the blade fitting groove, and the casing is inserted in the center of the casing. An impeller having a small blade on the outer circumference, which is integrally fitted to the rotating shaft and is rotatably disposed in the blade fitting groove of the casing and rotates and moves in the boost passage. A vacuum pump having a vortex flow pump structure including a bearing seal mechanism for maintaining liquid tightness between the inside of the casing, and a gas suction port for sucking only gas communicated with one end side of the pressurizing passage, A liquid introduction space formed from the rotary shaft fitting portion of the impeller to the bearing seal mechanism, and a liquid is introduced from the outside of the casing into the liquid introduction space on the bearing seal mechanism side simultaneously with the suction of the gas. And a discharge port for discharging gas and liquid, which is communicated with the other end of the pressurizing passage.

According to a second aspect of the present invention, there is provided a casing having an annular blade fitting groove and an annular pressurizing passage on an outer periphery of the blade fitting groove, and the casing is rotatably disposed in the blade fitting groove of the casing. A vacuum pump having a vortex flow pump structure, comprising: an impeller having a small blade on the outer periphery that rotates and moves in a booster passage, and a gas suction port for sucking only gas communicated to one end side of the booster passage, A liquid introducing pipe that is inserted into the gas suction port and has an opening at the front end of the liquid introducing port for introducing liquid at the inlet of the pressurizing passage, and a gas-liquid discharge outlet that communicates with the other end of the pressurizing passage. And a vacuum pump having an outlet.

According to a third aspect of the invention, a casing having an annular blade fitting groove and an annular pressurizing passage on the outer periphery of the blade fitting groove, and a rotary shaft inserted in the center of the casing are integrally fitted. For maintaining liquid tightness between the casing and the rotating shaft, and an impeller having a small blade on the outer periphery, which is rotatably disposed in the blade fitting groove of the casing and rotatably moves in the pressurizing passage. A vacuum pump having a vortex pump structure including a bearing seal mechanism, wherein a gas suction port for sucking only gas communicating with one end side of the booster passage and a rotary shaft fitting portion of an impeller in the casing. A liquid introduction space formed over the bearing seal mechanism, and a liquid introduction pump for forcibly introducing the liquid from the outside of the casing into the liquid introduction space on the bearing seal mechanism side at the same time when the gas is sucked. A vacuum pump; and a discharge opening for gas-liquid discharge communicating with the other end of the boost passages.

(Operation) In the invention according to claim 1, when the liquid is introduced into the liquid introduction space from the liquid introduction port of the casing, the liquid is radiated along the side surface of the impeller due to the centrifugal force and the pressure difference due to the rotation of the impeller. And a large amount of liquid is discharged into the annular pressure-increasing passage, especially at the inlet of the pressure-increasing passage, through the gap between the impeller and the blade fitting groove, and the liquid discharged into the annular pressure-increasing passage is sucked from the gas suction port. The gas is discharged from the discharge port while being agitated by the vortex flow generated between the impeller and the annular pressurizing passage together with the gas. At this time, the gas in the gas suction port is sucked into the vortex of the gas-liquid mixed phase that moves along the annular pressure-increasing passage, and a stronger vortex is formed than in the case where only the gas is sucked in. A vacuum degree is obtained. Furthermore, since the liquid introduced from the liquid introduction port of the casing into the liquid introduction space on the bearing seal mechanism side is supplied to the impeller after wetting the bearing seal mechanism, the bearing seal mechanism is lubricated and the bearing seal mechanism Prevent dry operation.

According to the second aspect of the invention, the liquid introduced into the gas suction port by the liquid introduction pipe is intensively discharged to the inlet portion having the lowest pressure in the pressurizing passage and is efficiently sucked into the pressurizing passage.
At the inlet of the pressurizing passage, the pressure around the liquid jet flow decreases according to the flow velocity of the liquid jet flow sucked into the pressurizing passage, so that the gas suction performance to the inlet of the pressurizing passage is improved. That is, a low pressure (negative pressure) that is proportional to the flow rate of the liquid is generated at the tip of the liquid introduction pipe that projects up to the inlet of the booster passage, and the gas suction port sucks gas into the liquid jet flow. Since the function is generated, the function as a vacuum pump is increased.

According to the third aspect of the invention, the liquid is introduced into the liquid introducing space in the casing by the liquid introducing pump, and the liquid is discharged to the annular pressure-increasing passage through the gap between the impeller and the blade fitting groove. The sucked gas and liquid are discharged from the discharge port while being agitated by the vortex flow generated between the impeller and the annular pressurizing passage. At this time, the gas in the gas suction port is sucked into the vortex of the gas-liquid mixed phase that moves along the annular pressure-increasing passage, and a stronger vortex is formed than in the case where only the gas is sucked in. A vacuum degree is obtained. Further, the liquid introduced into the liquid introduction space on the bearing seal mechanism side by the liquid introduction pump lubricates the bearing seal mechanism before being supplied to the vacuum pump, and prevents the bearing seal mechanism from dry operation.

(Embodiment) The present invention will be described below with reference to a first embodiment shown in FIGS. 1 and 2, a second embodiment shown in FIG. 3 and a third embodiment shown in FIG. And explain.

FIG. 1 shows an embodiment of a vortex flow pump structure that constitutes a vacuum pump 1 according to the invention of claim 1. In the drawing, 2 is a casing of the vacuum pump 1, and this casing 2 is a casing body 3 and a casing body 3. A casing cover 5 is airtightly fitted to an end surface of the casing body 3 via an O-ring 4, and a liquid introduction space 6 is formed in the center between the casing body 3 and the casing cover 5. An annular blade fitting groove 7 is formed in communication with the outer circumference of the liquid introduction space 6, and an annular pressurizing passage 8 is formed in communication with the outer circumference of the blade fitting groove 7.

As shown in FIG. 2, the inlet portion of the annular pressurizing passage 8
A gas suction port 9 is formed in communication with 8a, and a discharge port 10 is formed in communication with an outlet portion 8b of the ring-shaped pressurizing passage 8 between the inlet portion 8a and the outlet portion 8b of the ring-shaped pressurizing passage 8. A partition portion 11 is formed on the wall.

21 is an impeller, and this impeller 21 is a casing 2
Shaft inserted into the center of the liquid and entering the liquid introduction space 6
A boss portion 23 as a rotary shaft fitting portion fitted and fixed to one end portion of 22 and a disk portion 24 rotatably fitted in the blade fitting groove 7.
And a plurality of through holes 25 penetrating both side surfaces are provided on the center side of the disk portion 24, and a plurality of small blades 26 and a space between the small blades 26 on both outer peripheral sides of the disk portion 24. Is provided with a blade groove 27, and a small blade 26 and a blade groove on the outer periphery of the disk portion 24.
27 is configured to rotate in the annular pressurizing passage 8.

Further, one end of the rotary shaft 22 that penetrates into the liquid introduction space 6 is rotatably supported by the casing main body 3 by the bearing seal mechanism 28, and the casing main body 3 is also provided.
Is sealed so as to maintain liquid tightness between the rotary shaft 22 and the rotary shaft 22, and the other end is connected to a motor (not shown).

A liquid introducing space 6a is formed near the bearing seal mechanism 28, and the liquid introducing space 6a communicates with the liquid introducing space 6 formed near the boss portion 23 of the impeller 21 through the through hole 25. doing. In short, inside the casing 2, there are liquid introducing spaces 6 and 6a formed from the boss portion 23 of the impeller 21 to the bearing sealing mechanism 28.

A liquid introduction port 13 for introducing a liquid from the outside of the casing body 3 into the liquid introduction space 6a on the bearing seal mechanism 28 side is provided in the radial direction of the casing body 3, and the liquid introduction pipe 12 is screwed into the liquid introduction port 13. Then, a separate liquid introduction pump or liquid tank is connected to the liquid introduction pipe 12. The liquid introduction tube 12 is
It communicates with the liquid introduction space 6 formed in the central portion of the casing cover 5 through the liquid introduction port 13.

In order to obtain a vacuum pump function by the vacuum pump 1 configured as described above, the gas suction port 9 of air or the like is connected to the side of the vacuum device or the like requiring vacuum, and the discharge port 10 is opened to the atmosphere. While rotating the impeller 21, a separate external pump is used to pass from the liquid introduction port 13 of the casing body 3 through the liquid introduction space 6a on the bearing seal mechanism 28 side to the impeller 21.
When a liquid such as water is introduced around the boss portion 23 of the
The liquid flows toward the outer peripheral side along the side surface of the impeller 21 due to the centrifugal force due to the rotation of, and is discharged to the annular pressurizing passage 8 through the gap between the impeller 21 and the blade fitting groove 7.

In particular, as shown in FIG. 2, even in the pressurizing passage 8, a large amount of liquid is discharged (flushed) toward the inlet portion 8a having the lowest pressure. The largest amount of the liquid discharged into the inlet portion 8a of the pressurizing passage 8 efficiently winds the gas sucked from the gas suction port 9, and together with the gas, the blade grooves 27 of the impeller 21 and the annular shape. The gas moves along the annular pressurizing passage 8 while being agitated by the vortex generated between the gas and the pressurizing passage 8, and the gas becomes small bubbles and is discharged from the discharge port 10 together with the liquid. Therefore, a high vacuum pump function of efficiently sucking gas from the gas suction port 9 and discharging it from the discharge port 10 is obtained, which leads to an increase in the gas suction amount of the vacuum pump 1.

Further, the liquid introduced into the liquid introduction space 6a on the bearing seal mechanism 28 side from the liquid introduction port 13 of the casing main body 3 is supplied to the impeller 21 after the bearing seal mechanism 28 is once wetted. An external flushing effect of lubricating the sliding part of the bearing with a liquid is obtained, and the easiness of wear of the sliding part of the bearing seal mechanism 28 when the dry operation is prevented is prevented.

With a conventional water-sealed vacuum pump, noise is generated due to cavitation even at about 50 Torr when the saturated vapor pressure of the replenisher is approached, but the vacuum pump 1 of the vortex flow pump structure generates less noise due to cavitation. Therefore, it is possible to operate quietly even at a high degree of vacuum, and it is not necessary to provide an air ejector or the like to prevent noise due to cavitation.

The vacuum pump 1 can also have a gas-liquid mixing function or a foaming function. To obtain such a function, the gas to be mixed is sucked from the gas suction port 9 and the liquid to be mixed with the gas is introduced from the liquid introduction port 13 so that the rotating impeller 21 separates the gas and the liquid. It is possible to stir, mix the gas and the liquid, and discharge the mixture from the discharge port 10.

As a method of utilizing this function, for example, gas can be extracted from the tank, gas-liquid mixed, and then used for water treatment or fermentation by forming ultrafine bubbles. Further, since the discharge pressure of this pump can be increased, the liquid in the gas-liquid mixed state discharged from the discharge port 10 can be pumped to a predetermined location.

Next, FIG. 3 shows an embodiment of the vacuum pump according to the invention as set forth in claim 2, in which the liquid introducing pipe 29 is inserted from the upper part of the gas suction port 9 to the inlet part 8a of the annular pressurizing passage 8, The tip of the liquid introduction port 13 for introducing the liquid, which is provided in the liquid introduction pipe 29, is opened at the inlet portion 8a of the annular pressurizing passage 8, and the liquid introduction pipe 29 is introduced. The liquid is directly introduced into the inlet portion 8a of the pressurizing passage 8 having the lowest pressure through the port 13.

Then, the liquid introduced into the gas suction port 9 through the liquid introduction pipe 29 is intensively discharged to the inlet portion 8a having the lowest pressure in the pressurizing passage 8, is efficiently sucked into the pressurizing passage 8, and It works in the same way as in FIG.

That is, at the inlet portion 8a of the pressurizing passage 8, the flow velocity of the liquid sucked into the pressurizing passage 8 is high, and the pressure around the liquid jet flow decreases according to the jetting velocity of the liquid. The gas suction performance to 8a is improved. That is, the liquid introduction pipe projecting up to the inlet 8a of the pressurizing passage 8
At the tip of 29, low pressure (negative pressure) proportional to the flow rate of liquid
Occurs, and a gas suction function of sucking gas from the gas suction port 9 into the liquid jet flow occurs, so that the function as a vacuum pump increases.

Next, FIG. 4 shows an embodiment of the vacuum pump according to the invention described in claim 3, and in the first and second embodiments,
Liquid introduction tube using an external pump separate from the vacuum pump 1.
Although the liquid is introduced from 12, 29, in the present embodiment, the liquid is forcibly introduced by the internal liquid introduction pump 31 provided in parallel with the vacuum pump 1.

In short, as in the first embodiment, the liquid introduction spaces 6 and 6a are formed in the casing 2 from the boss portion 23 of the impeller 21 of the vacuum pump 1 to the bearing sealing mechanism 28, and from the outside of the casing 2 to the bearing sealing mechanism 28 side. The liquid introduction pump 31 for forcibly introducing the liquid into the liquid introduction space 6a is provided in the rotary shaft 22 and the casing body 3 which are common to the vacuum pump 1.

That is, the liquid introduction pump 31 is the vacuum pump 1
An eddy-current pump structure is provided similarly to the above, and an impeller 34 having a plurality of small blades 32 and blade grooves 33 on the outer periphery is fixed to the rotating shaft 22, and a blade fitting groove 35 is rotatably fitted to the impeller 34. The casing main body 3 is provided with an annular pressurizing passage 38 communicating with the suction port 36 and the discharge port 37, and a screw hole communicating with the discharge port 37 of the liquid introducing pump 31 (which originally serves as the discharge port of the liquid introducing pump 31). ) 41 is closed with a plug 42, and a communication groove 43 that communicates the pressurizing passage 38 with the liquid introduction space 6a is provided in the screw hole 41. The liquid introducing port 13 for introducing the liquid into the introducing space 6a is configured, and the screw hole 44 of the casing cover 5 is closed by the plug body 45.

Then, by rotating the rotary shaft 22, the impeller 21 of the vacuum pump 1 and the impeller 34 of the liquid introduction pump 31 rotate together, sucking the liquid from the suction port 36 of the liquid introduction pump 31 to form a communication groove. When introduced into the liquid introduction space 6a on the bearing seal mechanism 28 side from 43 (the discharge port 37 and the liquid introduction port 13), the liquid once wets the bearing seal mechanism 28, and then the through hole formed in the impeller 34. Through the impeller 21 of the vacuum pump 1
Therefore, the effect of external flushing in which the sliding portion of the bearing seal mechanism 28 is lubricated with liquid is obtained,
This prevents the sliding portion of the bearing seal mechanism 28 from being easily worn when it is dry-operated.

Further, the liquid flows to the outer peripheral side along the side surface of the impeller 21 due to the centrifugal force generated by the rotation of the impeller 21, and even in the annular pressurizing passage 8, particularly the pressurizing passage 8 through the gap between the impeller 21 and the blade fitting groove 7. A high vacuum pump function of discharging the gas to the inlet portion 8a having the lowest pressure, efficiently sucking the gas from the gas suction port 9 and discharging the gas from the discharge port 10 is obtained as in the embodiment of FIG. This leads to an increase in the amount of gas suctioned.

As described above, the vacuum pump 1 and the liquid introduction pump 31 are integrally arranged side by side, and the liquid is introduced through the inside of the casing 2, whereby a cheaper pump can be provided.

(Effect of the invention) According to the invention of claim 1, since the vacuum pump has a vortex flow pump structure, noise due to cavitation can be prevented, and quiet operation up to a high vacuum degree described later without the need for an air ejector or the like. It can be performed. In addition, the liquid introduced into the liquid introduction space from the liquid introduction port of the casing is discharged from the inside to the annular pressure-increasing passage, and the liquid is mixed into the vortex flow of the pressure-increasing passage. A high degree of vacuum is obtained on the gas suction port side. Further, since the bearing seal mechanism can be lubricated with the liquid introduced from the liquid introduction port of the casing into the liquid introduction space on the bearing seal mechanism side, the effect of external flushing can be obtained and the wear of the bearing seal mechanism due to the dry operation can be obtained. This can be prevented and the life of the bearing seal mechanism can be extended.

According to the second aspect of the present invention, the liquid introducing pipe intensively discharges the liquid to the inlet portion having the lowest pressure in the pressurizing passage so that the liquid is efficiently sucked into the pressurizing passage and is ejected from the tip of the liquid introducing pipe. Depending on the flow velocity of the liquid jet flow, the pressure around the liquid jet flow decreases and a gas suction function that sucks gas from the gas suction port into the liquid jet flow occurs, thus improving the gas suction performance at the inlet of the booster passage. It can be improved and the function as a vacuum pump can be increased.

According to the third aspect of the present invention, the liquid supplied to the liquid introduction space in the casing by the liquid introduction pump is discharged into the annular pressure-increasing passage, and the liquid is mixed with the vortex in the pressure-increasing passage. As a result, a strong gas suction performance is obtained, and a high degree of vacuum is obtained on the gas suction port side. Further, the liquid introduced into the liquid introduction space on the bearing seal mechanism side by the liquid introduction pump has the effect of external flushing, which lubricates the bearing seal mechanism and prevents its dry operation. The life can be extended.

[Brief description of the drawings]

FIG. 1 relates to a vacuum pump of the present invention. FIG. 1 is an axial sectional view showing an embodiment of a vacuum pump according to the invention of claim 1, FIG. 2 is a radial sectional view thereof, and FIG. FIG. 4 is a radial sectional view showing an embodiment of the vacuum pump according to the invention of claim 2, and FIG. 4 is an axial sectional view showing an embodiment of the vacuum pump according to the invention of claim 3. DESCRIPTION OF SYMBOLS 1 ... Vacuum pump, 2 ... Casing, 6,6a ... Liquid introduction space, 7 ... Blade fitting groove, 8 ... Pressure rising passage, 9 ... Gas suction port,
10 ... Ejection port, 13 ... Liquid introduction port, 21 ... Impeller, 22 ... Rotating shaft, 23 ... Boss as a rotating shaft fitting part, 26 ... Small blade, 28
… Bearing seal mechanism, 29… Liquid introduction pipe, 31… Liquid introduction pump.

Claims (3)

(57) [Claims] 1. A casing having an annular blade fitting groove and having an annular pressurizing passage on the outer periphery of the blade fitting groove, and a casing integrally fitted to a rotary shaft inserted in the center of the casing. An impeller having a small blade on the outer periphery, which is rotatably disposed in a blade fitting groove of a casing and has a rotary movement in the boosting passage, and a bearing sealing mechanism for maintaining liquid tightness between the casing and a rotating shaft. A vacuum pump having a vortex flow pump structure including: a gas suction port for sucking only gas communicating with one end side of the booster passage; and a bearing seal from a rotary shaft fitting portion of an impeller in the casing. A liquid introduction space formed over the mechanism, a liquid introduction port for introducing liquid from the outside of the casing into the liquid introduction space on the bearing seal mechanism side at the same time as sucking in the gas, and the other end side of the pressurizing passage And a discharge port for discharging gas and liquid which is communicated with the vacuum pump. 2. A casing having an annular blade fitting groove and an annular pressurizing passage on the outer periphery of the blade fitting groove, and a rotatably disposed inside the blade fitting groove of the casing. A vacuum pump having an eddy-current pump structure, comprising: an impeller having a small blade on its outer periphery that rotates and moves, and a gas suction port for sucking only gas communicated with one end side of the pressurizing passage, and the gas suction port. A liquid introducing pipe that is inserted into the mouth and has an opening at the tip of the liquid introducing port for introducing liquid at the inlet of the pressurizing passage; and a discharge port for gas-liquid discharge that communicates with the other end of the pressure increasing passage. A vacuum pump characterized by being provided. 3. A casing having an annular blade fitting groove and having an annular pressurizing passage on the outer circumference of the blade fitting groove, and a casing integrally fitted to a rotary shaft inserted in the center of the casing. An impeller having a small blade on the outer periphery, which is rotatably disposed in a blade fitting groove of a casing and has a rotary movement in the boosting passage, and a bearing sealing mechanism for maintaining liquid tightness between the casing and a rotating shaft. A vacuum pump having a vortex flow pump structure including: a gas suction port for sucking only gas communicating with one end side of the booster passage; and a bearing seal from a rotary shaft fitting portion of an impeller in the casing. A liquid introduction space formed over the mechanism; a liquid introduction pump for forcibly introducing the liquid into the liquid introduction space on the bearing seal mechanism side from the outside of the casing at the same time when the gas is sucked; And a discharge port for discharging gas and liquid, which is communicated with the other end of the passage.