KR100795897B1 - Vacuum breaker system of water turbine for water-power generation - Google Patents

Abstract

A vacuum breaker system of a water turbine for waterpower generation is provided to prevent an adverse water flow to a pit room and to protect erosion of a water turbine by preventing infiltration of foreign material to a disk and a seat with a hole plate and by settling cavitation promptly through coercive air injection with an air injection pipe. A vacuum breaker system of a water turbine for waterpower generation including a vacuum housing(6), a hollow seat(11), a rod(8) having a disk(7), an elastic part(10), and a cover part(9) installed at a through hole(5) of a pit room(3), further comprises the followings: a butterfly valve(101) installed with a bolt between the through hole and the vacuum housing, to block water flowing; a valve opening and closing unit(104) operating an operating rod(103) of the butterfly valve; a hole plate(114) having many through holes(114a) inside, connected at one of an upper end or a lower end of the butterfly valve or a lower end of a connecting pipe(113) installed between the butterfly valve and the through hole of the pit room with preset height, to block infiltration of foreign material to the through hole; an air injection pipe(115) with multiple nozzles connected under the butterfly valve; a second air compressor connected to the air injection pipe to supply air; and an air control unit injecting air through the nozzle when the disc connected to the rod descends.

Description

Vacuum breaker system of water turbine for water-power generation

1 is a view showing the structure of a hydroelectric aberration and a rotating device.

Figure 2a is a functional diagram showing the structure and operation state of the conventional breaker breaker of the hydraulic power aberration.

Figure 2b is a cross-sectional view showing the structure and operation state of the conventional breaker breaker of the hydraulic power aberration.

Figure 3a is a cross-sectional view showing the structure and operating state of the burst breaker system according to the present invention.

Figure 3b is a cross-sectional view showing the structure and operating state of the burst breaker system according to the present invention.

Figure 4 is a view showing the discharge state of the air supply line supplied to the pneumatic cylinder and the air injection pipe of the valve opening and closing member according to the present invention.

5 is a perspective view showing a perforated network according to the present invention.

<Description of the symbols for the main parts of the drawings>

101: butterfly valve 102: valve plate

103: operating rod 104: valve opening and closing member

105: valve housing 106: fixing bracket

107: pinion 108: rack

109: pneumatic cylinder 110: the first compressor

111: first air supply pipe 112: air valve

113: connector 114: perforation network

115: air spray pipe 116: second compressor

117: second air supply pipe 118: air regulator

119: detection hole 120: light sensor

The present invention is installed in the housing housing at least one through-hole formed to be penetrated by the aberration blades in the pit room of the aberration bearing for the hydroelectric generator, and is inclined to be in close contact with the inner diameter of the housing housing, the inclined surface axially to the inner side connected to the bottom A hollow sheet, a rod penetrating through the first through hole formed in the upper part of the housing, and a disc having an inclined surface corresponding to the inclined surface of the upper sheet to be in close contact with the inclined surface of the seat, and inserted into the outer diameter of the rod penetrating upward through the first through hole. It relates to a hydro-powered aberration brake breaker system comprising an elastic member and a cover member coupled to the top of the rod so that the elastic member supports the rod upwards, in particular, it occurs in the water during the start or stop of the generator Burr breaker to suppress cavitation phenomenon in which previously released air bubbles are destroyed Improves the reliability of the rotating machine by preventing water from flowing backward in the pit room, foreign matters flowing back through the backflow, and being caught on the contact surface of the disk and seat of the burst breaker. In addition to the Kim, the pit room is drained at a certain level to prevent water from being released due to the flooding of the aberration bearings. It relates to a hydroelectric aberration brake breaker system, which enables the breaker to be automatically closed quickly, thereby improving worker safety.

In general, hydroelectric power refers to a method of generating a turbine by using a drop of water, and since the operation procedure of the facility is simple and natural energy (kinetic energy of falling water) is used as it is, steam, like nuclear power or nuclear power, No turbine is required, no cooling system to cool the heat.

In addition, the aberrations used in the hydroelectric power are applied differently according to the drop, and most of them are Francis aberrations, but in the case of a large drop, Pelton aberration is used. do.

As described above, the power generation in the hydroelectric power plant is configured to generate electricity by using the rotational force generated while the water wheel 1 rotates by allowing water to be supplied to the water wheel 1a as shown in FIG. 1. Same as the known fact.

When the aberration bearing 2 is coupled to the aberration 1 of the hydroelectric power plant, when the aberration bearing 2 comes into contact with water, the water is contaminated with the oil of the aberration bearing 2, and the water is discharged. If the river or river is contaminated, the waterway is formed in the lower pit room (3) so that the water supplied to the aberration (1) is separated and protected from the aberration bearing (2) by the pit room (3).

However, when water is formed in the lower part of the pit room 3 and thus the water supplied to the aberration 1 is blocked from the upper part of the pit room 3, the generator is started and the water is supplied to the aberration 1 at the same time. If so, a vacuum phenomenon occurs temporarily in the lower part of the pit room 3 and the aberration 1.

In addition, even when the generator stops operating, a vacuum phenomenon occurs in the lower portion of the pit room 3 and the aberration 1 because the water supplied to the aberration 1 is suddenly stopped as described above.

The above-mentioned vacuum phenomenon refers to a phenomenon in which the air bubbles generated in the fluid are continuously destroyed when the inside of the fluid becomes below the saturated vapor pressure due to the sudden flow of the fluid, called cavitation.

At this time, the surface of the aberration blade 1a is eroded due to the destruction of air bubbles. If this phenomenon persists, the performance of the aberration generator is deteriorated, as well as the vibration and noise increase, which greatly affects the reliable operation of the rotating equipment. Will result.

The conventional problem solving means proposed to solve the above problem is the burst breaker 4 as shown in Figs. 2A and 2B.

The vacuum breaker 4 is installed in the pit room 3 shown in FIG. 1, and when a vacuum phenomenon occurs in the aberration blade 1a when the generator is started or stopped, as shown in FIG. 2B. The outside air is taken in through the through holes 5 formed in the pit room 3 by the vacuum. At this time, the disk 7 and the rod 8 of the vacuum housing 6 coupled to the through holes 5 are sucked. ) And the cover member 9 are lowered while compressing the elastic member 10 at the same time as the intake.

Therefore, while the seat 11 and the disk 7 in close contact with the inner diameter surface of the vacuum housing 6 are lowered, a space is formed between the seat 11 and the disk 7 and along the space. As shown in FIG. 2B, external air is supplied to the lower part of the pit room 3, that is, the aberration blade 1a through the through hole 5, thereby eliminating a sudden vacuum phenomenon.

However, in such a breaker (4) there is a problem that can not completely solve the conventional vacuum phenomenon because the amount of air supplied instantaneously in response to the vacuum phenomenon is limited.

That is, the vacuum breaker (4) can not completely eliminate the vacuum phenomenon, there is still a problem that the aberration blade (1a) is eroded.

In addition, since the generator is started and the water is supplied to the aberration 1, the water contains a large amount of moss, plants, etc., as shown in FIG. 2B, the disk 7 compresses the elastic member 10 and then lifts it. In the process of returning, moss, plants, etc., included in the spinning wheel, are caught in the disk 7 and the sheet 11 to reduce the adhesion between the disk 7 and the sheet 11.

Thus, as shown in FIG. 2A, the water supplied to rotate the aberration 1 flows back into the through hole 5 and the vacuum housing 6 through the gap between the seat 11 and the disk 9 to pit. It develops into the problem of flooding the room 3.

Immersion of the pit room 3 as described above not only adversely affects various kinds of electronic and electrical components mounted in the pit room 3, but also mixes with a smooth oil which smoothly drives each equipment. As water contaminated with oil is drained, it develops problems such as secondary pollution of rivers and rivers and destruction of ecology.

In addition, if the immersion continues to erode the aberration bearing (2), since the rotation of the aberration bearing (2) is not made naturally, the reliability of the rotating device is lowered, as well as maintenance that is put into the solution of these problems And there is a problem that the maintenance cost increases.

On the other hand, when the adhesion between the disk 7 and the sheet 11 is weakened or water is caused to flow backward due to a pinch of foreign matter as described above, in order to solve such a backflow phenomenon, a worker directly moves to the pit room 3. The shut-off valve 12 to enter and close the inner diameter of the venting housing 6 was closed. As shown in FIG. 2A, the shut-off valve 12 is mounted at the bottom of the venting housing 6 to operate the lever 13. There is a problem that the structure can be opened and closed only by the rotation of) so that the action is not made smoothly in the event of an emergency, and since the pit room 3 is narrow, there are problems such as many difficulties in its operation.

In order to solve the above problems, the first of the present invention, when the immersion of the pit room due to the reverse flow of the breaker breaker automatically blocks the breaker to prevent backflow, and the second, the disk and the sheet tightly Third, the breaking breaker of hydro-powered aberration, which blocks the inflow of foreign substances by the reverse flow and enables the supply of a large amount of air immediately in response to the cavitation caused by the aberration. The purpose is to provide a system.

The above object is to be installed in the at least one through-hole to be penetrated by the aberration wing in the pit room of the aberration bearing for the hydroelectric generator, and is built to be in close contact with the inner diameter of the vacuum housing and obliquely toward the center of the inner diameter from the bottom A rod having an inclined surface connected to the hollow sheet, a rod having an inclined surface corresponding to the upper outer diameter surface thereof penetrated through the first through hole formed in the upper portion of the housing, and having an inclined surface corresponding to the inclined surface of the sheet; In the hydropower aberration brake breaker system comprising an elastic member inserted into the outer diameter of the, and the cover member is coupled to the top of the rod so that the elastic member supports the rod upwardly, bolting coupling between the through hole and the vacuum housing A butterfly valve configured to block water passing through the through hole from the through hole; A valve opening and closing member configured to rotate the operating rod for operating the valve plate of the butterfly valve to open and close the butterfly valve; A plurality of through-holes are formed so as to block foreign substances flowing into the through-holes by being inserted into at least one of the upper and lower ends of the butterfly valves and the lower end of the connection pipe having a predetermined height coupled between the butterfly-valve and the through-holes of the pit room. Perforated network; An air injection pipe coupled to a lower end of the butterfly valve and having a plurality of nozzles coupled thereto; A second compressor connected to the air injection pipe to supply air; And a control means of the air to eject air to the nozzle when the disk coupled to the rod is lowered, and to block the air so that the air is not injected to the nozzle when the disk is raised and lowered. Achieved by a burst breaker system.

Here, the valve opening and closing member is fixed to the one end of the valve housing so that the operating rod can be rotated at the end of the operating rod protruding to one end of the valve housing of the butterfly valve, the fixed bracket having a receiving space of a predetermined size; A pinion arranged at one end of the operating rod at a predetermined position; A rack engaged with the pinion and coupled to reciprocate at a predetermined position of the fixing bracket; A pneumatic cylinder coupled to the end of the rack so that the rack reciprocates, and fixed to the fixing bracket; And control means for the pneumatic cylinder to allow the pneumatic cylinder to be controlled to drive either forward or backward.

The control means for the pneumatic cylinder may include: a level sensor installed at the pit room at a predetermined position to generate a signal when the water level flowing into the pit room reaches a predetermined level; A first compressor configured to supply air to the pneumatic cylinder; When the high level signal is transmitted from the level sensor, it is coupled to the first air supply pipe connected between the pneumatic cylinder and the first compressor includes a first control unit to turn on the air valve for adjusting the opening and closing of the air to supply air.

In addition, when the high level signal is transmitted by the level sensor, the first control unit drives the drain motor and the pump to discharge water introduced into the pit room, and when the low level signal is transmitted by the level sensor, After stopping the pump, it is preferable to turn off the air valve so that the butterfly valve is opened to block the supply of air.

In addition, it is preferable to further include a connection pipe of a predetermined height coupled between the butterfly valve and the through hole of the pit room.

The control means for air may include an air regulator installed in a second air supply pipe connected between the air injection pipe and the second compressor; A sensing hole drilled horizontally at a predetermined position of the rod; An optical sensor installed at an upper end of the vacuum housing with a rod therebetween to generate a signal when the detection hole reaches the installation position while the rod descends; And a second controller configured to control the air regulator to control the air to be injected for a predetermined time by controlling the air regulator when the signal generated by the optical sensor is transmitted.

Hereinafter, the configuration and operation of the present invention will be described with reference to FIGS. 3A to 5, but the components and fit rooms 3 of the conventional breaker 4, which are conventional technical configurations, will be referred to with reference numerals in the related drawings. This will be described.

First, the brake breaker 4 is the same as the conventional configuration, and comprises a vacuum housing 6, a seat 11, a disk 7, an elastic member 10, a rod 8 and a cover member 9 The rubber housing 6 is installed in the at least one through-hole 5 formed radially about the rotation axis 1b of the aberration 1 in the pit room 3, and the inner diameter of the rubber housing 6 therein. The hollow sheet 11 is coupled to be in close contact with the surface, the inner diameter surface of the sheet 11 is formed with an inclined surface of which the bottom is inclined upward toward the inner center.

In addition, the disk 7 having the inclined surface corresponding to the inclined surface of the sheet 11 on the upper outer diameter surface so as to be in close contact with the inclined surface of the sheet 11 passes through the guide hole 6a formed at the upper end of the vacuum housing 6. Is coupled to the bottom of the rod 8.

In addition, a cover member 9 of a predetermined width is bolted and coupled to the end of the rod 8 that is upwardly passed through the guide hole 6a of the vacuum housing 6, and the vacuum housing 6 Between the upper end and the cover member 9, the elastic member 10 is elastically installed so as to be spaced a predetermined distance apart from the outer diameter of the rod 8 to support the cover member 9 upwardly.

Therefore, when the cavitation phenomenon occurs in the aberration 1 and becomes a vacuum state, the disk 7 is lowered by the inhalation of the vacuum, and at this time, the rod 8 and the cover member coupled to the disk 7 As 9) descends, the elastic member 10 is compressed.

At this time, as shown in FIG. 2B, the outside air is supplied to the aberration 1 through the vent hole, the seat 11, and the through hole 5 of the venting housing 6, and the vacuum state is solved to eliminate the disc 7. When the force to intake) disappears, the elastic member 10 elastically supports the cover member 9 upwards, so that the cover member 9 and the rod 8 and the disk 7 are lifted and lifted. The inclined surface of 7) is in close contact with the inclined surface of the sheet 11, so that backflow can be prevented, and the configuration and action are the same as those of the conventional brake breaker 4.

The present invention couples the butterfly valve 101 to the conventional brake breaker 4 described above, and automatically opens and closes the butterfly valve 101 so that urgent measures are taken against the backflow of water.

That is, the butterfly valve 101 is provided at the lower end of the vacuum housing 6, the butterfly valve 101 is a conventional valve for opening and closing the diameter, so the description of the detailed structure will be omitted.

Then, the operating rod 103 for operating the valve plate 102 of the butterfly valve 101 is protruded to one end of the valve housing 105, one end of the protruding operating rod 103 is the valve opening and closing member 104 The valve opening and closing member 104 is coupled to the fixed bracket 106 at one end of the valve housing 105 from which the operating rod 103 protrudes. At the same time, the fixing rod 106 is coupled to the operating rod 103 as shown in FIG. 3A so that the operating rod 103 can be rotated.

Here, one end of the operating rod 103, the pinion 107 is to be built up, and the rack 108 for engaging the pinion 107 to rotate the pinion 107 at a predetermined position of the fixing bracket 106. 3a and 3b, the linear reciprocating motion of the rack 108 allows the pinion 107 to be rotated left and right.

Meanwhile, the piston rod 8 of the pneumatic cylinder 109 is coupled to the end of the rack 108 so that the rack 108 reciprocates. The pneumatic cylinder 109 is moved forward and backward by the control means of the pneumatic cylinder. It is possible to drive control to either.

The control means of the pneumatic cylinder is composed of a level sensor, the first compressor 110, the air valve 112 and the first control unit (not shown), the level sensor is the bottom surface of the pit room (3) or It is installed in the upper position of the predetermined distance from the floor to detect the water level, and in this case, when the level sensor detects the water level to generate a signal to limit the low level or high level level to generate a low level signal or a high level signal desirable.

Here, the level sensor may be a floating switch to detect the water level in general, but the present invention is not limited to the type of the level sensor, and since the borrowed off-the-shelf product, a detailed description thereof will be omitted.

The first compressor 110 is connected to the pneumatic cylinder 109 and the first air supply pipe 111 to supply air, and may be installed in the pit room 3 or installed outside the pit room 3. It may be, which can be adjusted by the pipe length of the first air supply pipe 111, and the purpose of the present invention can be sufficiently achieved even if it is installed in the pit room (3) and the outside without convenience according to the present invention is It is not limited to this.

On the other hand, when the high level signal is transmitted from the level sensor, the first control unit is coupled to the first air supply pipe 111 to turn on the air valve 112 for adjusting the opening and closing of the air to supply air, and at the same time the level When the high level signal is transmitted by the sensor, a drain motor (not shown) and a pump (not shown) are driven to discharge water introduced into the pit room 3, and when the low level signal is transmitted by the level sensor, After stopping the drain motor and the pump, it is preferable to turn off the air valve 112 so that the butterfly valve 101 is opened to block the supply of air.

In addition, between the butterfly valve 101 and the through hole 5 of the pit room 3, the connection pipe 113 having a predetermined height is coupled with the one shown in FIGS. It is desirable to allow the water level to be suppressed by allowing the water level to overflow to countercurrent at and rise in water.

Therefore, a leak occurs between the disk 7 and the seat 11, so that the water level inside the pit room 3 rises. At this time, when the water level of the incoming water reaches a certain level, the level sensor detects this and 1 Transmit signal to the controller.

Accordingly, the first control unit opens the air valve 112 so that the air generated from the first compressor 110 is supplied to the pneumatic cylinder 109, and the air supplied to the pneumatic cylinder 109 is a piston rod. (8) is advanced, the rack 108 coupled to the end of the piston rod (8) to be advanced rotates the pinion (107) to open the valve plate 102 of the operating rod 103 and the butterfly valve 101 By rotating as shown in FIG. 3B, the butterfly valve 101 can be shut off.

Here, the valve plate 102 shown in FIG. 3B does not show a completely closed state, but shows a closed state in the state of FIG. 3A.

At this time, when the high level signal is transmitted to the first control unit, the first control unit drives the drain motor and the pump to discharge the water introduced into the pit room 3, and the water level of the pit room 3 by the pump. When the low level reaches a predetermined level, the low level signal is transmitted to the first control unit by the level sensor. Accordingly, the first control unit controls the driving of the drain motor and the pump to be stopped.

Therefore, the worker inspects the water level in the pit room 3 day by day, and automatically does not need to manually shut off the vacuum housing 6 to prevent water from flowing back into the pit room 3 and entering the pit room 3. Simultaneously with the closing housing (6) will be able to discharge the water inside the pit room (3) to the outside.

In addition, the at least one of the upper and lower ends of the butterfly valve 101 and the lower end of the connection pipe 113 is inserted into the perforated network 114 having a plurality of through holes 114a as shown in FIGS. 3A, 3B and 5. Foreign matter between the inclined surface of the disk 7 and the inclined surface of the sheet 11 by combining by filtering the other plants and foreign matter contained in the water during the lowering of the disk (7) due to the cavitation phenomenon and the reverse flow of water by the perforated network 114 It is desirable for this intervening phenomenon to be prevented beforehand.

On the other hand, the lower end of the butterfly valve 101 is a plurality of nozzles (not shown) is coupled to the air injection pipe 115 is coupled, the second air injection pipe 115 is connected to the second compressor 116 Air is supplied from the nozzle of the air injection pipe 115 when the disc 7 coupled to the rod 8 descends, and when the disc 7 is elevated, the air injection of the nozzle Bar to control, the control means of the air to control the air injection of the air injection pipe 115 is as follows.

The air control means connects the second air supply pipe 117 between the air injection pipe 115 and the second compressor 116, and the air regulator 118 at a predetermined position of the second air supply pipe 117. Install).

In addition, at a predetermined position of the rod 8, as shown in FIGS. 3A and 3B, the sensing hole 119 is drilled horizontally, and at the same time, the rod 8 is interposed between the rod housing 6 and the light. Sensor 120 (light emitting element 120a, light receiving element 120b) is spaced apart from the installation hole (119) when the detection hole 119 reaches the installation position of the optical sensor 120 while the rod 8 is lowered The light of the light emitting element 120a is received by the light receiving element 120b through this, and at this time, the signal is transmitted from the light receiving element 120b to the second control unit (not shown), whereby the second control unit is an air injection pipe. The air conditioner 118 is controlled to inject air for a predetermined time with the nozzle of 115.

Meanwhile, the first compressor 110 and the second compressor 116 may be utilized as one compressor as shown in FIG. 4, and the first controller and the second controller are also integrated into one controller. The present invention is not limited to this as it may control the equipment.

However, since the first air supply pipe 111 and the second air supply pipe 117 are supplied from one compressor and are supplied with air to different equipment, respectively, they may be present separately as shown in FIG. 4.

Accordingly, when the rod 7 descends due to the cavitation phenomenon, the detection hole 119 of the rod 8 is moved by the light sensor 120 (light emitting element 120a, light receiving element 120b). In this case, the second control unit controls the air regulator 118 by a signal transmitted by the optical sensor 120, so that a large amount of air is injected downward through the nozzle of the air injection pipe 115. Therefore, the insufficient air can be sufficiently supplied during the cavitation phenomenon to suppress the cavitation caused by the vacuum.

As described above, the present invention provides a perforated network to prevent the foreign matter from intervening between the disc and the sheet, thereby maintaining a close contact between the disc and the sheet to prevent backflow of water, and even between the disc and the sheet. Even though the water flows backward due to the close relationship between the two valves, if the level sensor detects the level of water flowing into the pit room, the butterfly valve automatically closes to block the water flow back and the drain motor and pump automatically. It can be driven to discharge the water flowing into the pit room, and in particular, by forcibly injecting air when the disk is lowered through the air injector, the vacuum breaker does not sufficiently solve the aberration generated by the aberration breaker alone The problem can be solved, which has the effect of solving the erosion problem of aberration caused by cavitation phenomenon. .

Claims (5)

A hollow housing installed in at least one through hole formed to penetrate the aberration blade in the pit room of the hydro wheel bearing for the hydroelectric generator, and the hollow housing in which the slanted surface is connected obliquely toward the inner diameter center at the bottom to be in close contact with the inner diameter of the vacuum housing. A rod having a shape sheet, a disk penetrating through the first through hole formed in the upper part of the housing and having an inclined surface corresponding to the inclined surface of the seat, and a rod penetrating upward through the first hole. In the hydropower aberration brake breaker system comprising an elastic member and a cover member coupled to an upper end of the rod such that the elastic member supports the rod upwardly. A butterfly valve bolted between the through hole and the vacuum housing to block water passing from the through hole to the vacuum housing; A valve opening and closing member configured to rotate the operating rod for operating the valve plate of the butterfly valve to open and close the butterfly valve; A plurality of through-holes are formed so as to block foreign substances flowing into the through-holes by being inserted into at least one of the upper and lower ends of the butterfly valves and the lower end of the connection pipe having a predetermined height coupled between the butterfly-valve and the through-holes of the pit room. Perforated network; An air injection pipe coupled to a lower end of the butterfly valve and having a plurality of nozzles coupled thereto; A second compressor connected to the air injection pipe to supply air; And a control means of the air to eject air to the nozzle when the disk coupled to the rod is lowered, and to block the air from being ejected from the nozzle when the disk is elevated. Burr Breaker System. The method of claim 1, The valve opening and closing member, A fixed bracket coupled to one end of the valve housing so that the operating rod can be rotated at an end of the operating rod protruding from one end of the valve housing of the butterfly valve; A pinion arranged at one end of the operating rod at a predetermined position; A rack engaged with the pinion and coupled to reciprocate at a predetermined position of the fixing bracket; A pneumatic cylinder coupled to the end of the rack so that the rack reciprocates, and fixed to the fixing bracket; And a control means for the pneumatic cylinder which enables the pneumatic cylinder to be controlled to be driven either forward or backward. The method of claim 2, The control means of the pneumatic cylinder, A level sensor installed at a predetermined position of the pit room and generating a signal when the water level flowing into the pit room reaches a predetermined level; A first compressor configured to supply air to the pneumatic cylinder; And a first control unit coupled to the first air supply pipe connected between the pneumatic cylinder and the first compressor to turn on an air valve to control the opening and closing of the air when the high level signal is transmitted from the level sensor. A hydraulic breaker system for hydro-powered water wheels. The method of claim 3, The first control unit, When the high level signal is transmitted by the level sensor, the drain motor and the pump are driven to discharge the water introduced into the pit room. When the low level signal is transmitted by the level sensor, the drain motor and the pump are stopped and then the butterfly valve. A hydraulic breaker hydraulic breaker system, characterized in that to shut off the supply of air by turning off the air valve to open. The method of claim 1, The control means of the air, An air regulator installed in a second air supply pipe connected between the air injection pipe and a second compressor; A sensing hole drilled horizontally at a predetermined position of the rod; An optical sensor installed at an upper end of the vacuum housing with a rod therebetween to generate a signal when the detection hole reaches the installation position while the rod descends; And a second control unit for controlling air to be injected for a predetermined time by controlling an air regulator when a signal generated by the optical sensor is transmitted.

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