WO2021246029A1

WO2021246029A1 - Blower

Info

Publication number: WO2021246029A1
Application number: PCT/JP2021/011827
Authority: WO
Inventors: 和夫坂田; 薫奥野; 龍男木下
Original assignee: 株式会社大阪送風機製作所
Priority date: 2020-06-04
Filing date: 2021-03-23
Publication date: 2021-12-09
Also published as: CN114207287A; JPWO2021246029A1; KR102653737B1; KR20210151860A; JP7319636B2; CN114207287B

Abstract

Provided is a blower that includes a rotating shaft (21) inserted into a shaft hole (12) of a casing (10) in which a gas passage (11) is formed, an impeller (22) supported by the rotating shaft (21), and a sealing device (30) sealing the shaft hole (12), wherein the sealing device (30) includes first and second seal rings (31) and (32) surrounding the rotating shaft (21) near the shaft hole (12), a shaft sealing box (33) surrounding these seal rings, a static pressure gas sealing means (40) in which is formed a main sealing chamber (42) for introducing seal air having a pressure higher than that inside a gas passage (11) to prevent exhaust gas from leaking from the gas passage (11) to the atmosphere side, and a backup sealing means (60) that includes an annular third seal ring (61) surrounding the rotating shaft (21) on an axially outer side with respect to the shaft sealing box (33) and forms an auxiliary sealing chamber (62) limiting the leakage of seal air from the main sealing chamber (42) to the atmosphere side.

Description

Blower

The present invention relates to a blower, particularly to a blower suitable for an exhaust gas recirculation system of a large engine.

As a blower that inhales and boosts the gas to be blown, a recirculation blower that boosts the exhaust gas from the system that outputs power and electric power and recirculates it to the system, and the gas supplied to the system (low pressure recirculation). Auxiliary blowers that boost pressure (including gas) are known.

For example, as one of the exhaust gas emission reduction technologies for engines such as marine diesel engines, a part of the exhaust gas of the engine is recirculated to the intake side of the engine (meaning the air supply side when a scavenging action is performed) and recirculated. EGR systems (exhaust gas recirculation systems) that reduce NOx (exhaust gas recirculation) in exhaust gas have become widespread. In such EGR systems, EGR that boosts a part of exhaust gas to a pressure that allows recirculation is possible. The blower is described in, for example, Patent Document 1 and Patent Document 2.

Further, for example, Patent Document 3 describes that the recirculated exhaust gas flow rate can be controlled by its own blower rotation speed and is equipped with a rotation sensor for measuring the blower rotation speed.

Further, in Patent Document 4, a centrifugal blower in which an impeller and a rotating shaft are integrally molded with a resin material and housed in a housing is provided. A first and second seal rings made of a fluororesin having an inner peripheral surface having substantially the same diameter are provided, and a seal air is supplied to the housing internal space between the two seal rings. ..

Japanese Unexamined Patent Publication No. 2011-157959 Japanese Unexamined Patent Publication No. 2012-172647 Japanese Unexamined Patent Publication No. 2002-332919 Japanese Unexamined Patent Publication No. 2016-89671

However, in the conventional blower as described above, the EGR gas that is boosted in the impeller casing and should be recirculated to the engine is suppressed from entering the internal space side of the housing through the shaft hole of the impeller rotation shaft. Therefore, if the pressure of the seal air supplied to the impeller side space inside the housing is set sufficiently higher than the inside of the impeller casing, the amount of seal air leaking from the impeller side space to the motor side space side communicating with the outside of the housing (atmosphere side). There was a problem that the number increased.

Therefore, the conventional blower has a problem that the power consumption of the drive motor for driving the seal air supply source increases, and a problem that it is difficult to adopt it for the EGR blower of the marine engine installed in the ship. Was there.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a blower capable of suppressing the power consumption of a seal air supply source, and also to provide a marine engine. It is an object of the present invention to provide a blower suitable for an EGR blower.

(1) In order to achieve the above object, the blower according to the present invention has a casing in which a gas passage and a shaft hole communicating with the gas passage are formed, and a rotary shaft rotatably inserted into the shaft hole of the casing. A blower provided with an impeller supported by the rotating shaft and housed in the casing, and a sealing device for sealing the shaft hole, wherein the sealing device is provided in the vicinity of the shaft hole. A pair of annular first and second seal rings surrounding the first and second seal rings, and a pair of annular wall portions surrounding the first and second seal rings, which are integrally coupled to the annular wall portions on both sides of the rotation axis in the axial direction. An annular shaft seal box having an inner side wall portion, and a higher pressure seal air than the inside of the gas passage are introduced into the shaft seal box, and the first and second seal rings are closely attached to the pair of inner side wall portions. The static pressure gas sealing means for forming the main sealing chamber to prevent the exhaust gas from leaking from the gas passage to the atmosphere side, and the axially outer side separated from the gas passage with respect to the shaft sealing box. It has an annular third seal ring that surrounds the axis of rotation and comprises a backup seal means that forms an auxiliary seal chamber that limits the leakage of seal air from the main seal chamber to the atmosphere side. ..

With this configuration, in the present invention, the static pressure gas sealing means introduces the sealing air having a higher pressure than that in the gas passage into the main sealing chamber formed between the first and second sealing rings, so that the sealing air in the blower is introduced. Exhaust gas is surely prevented from leaking from the gas passage side to the atmosphere side. Moreover, when the front-rear differential pressure of the second seal ring is suppressed by the third seal ring of the backup sealing means, the front-rear differential pressure of the third seal ring is also suppressed, so that the front-rear differential pressure of each seal ring is adjusted. It is possible to effectively reduce the leakage flow rate of the sealed air to the atmosphere side.

(2) In a preferred embodiment of the present invention, the casing is formed with a gas passage into which a part of the exhaust gas of the engine can be introduced and a shaft hole communicating with the gas passage, and the impeller is the gas. The exhaust gas introduced into the passage and boosted can be recirculated to the engine.

In this case, it is suitable for an EGR blower that recirculates the exhaust gas of the engine in order to reduce NOx and the like.

(3) In a preferred embodiment of the present invention, of the first and second seal rings, at least the second seal ring on the atmosphere side is composed of a plurality of arcuate segment seal members adjacent to each other in the circumferential direction. A first facing surface in which the plurality of segment seal members spread in the axial and radial directions and face each other in the circumferential direction, and a second facing surface in which the plurality of segment seal members spread in the circumferential direction and the radial direction and face each other in the axial direction. Can be configured to have.

By doing so, the minute gap shape between the inner peripheral surface shape and the end shape of the plurality of segment seal members can be appropriately set, and the flow rate of the seal air passing through the minute gap of the second seal ring and the second seal air flow rate can be set. It is possible to stably secure the front-rear differential pressure of the seal ring of 2.

(4) In a preferred embodiment of the present invention, the backup sealing means attaches the third seal ring to the outside in the radial direction and in the axial direction on the outward side in the axial direction away from the gas passage with respect to the shaft sealing box. The configuration may further include an external annular member that covers from the outside and an elastic member that urges the third seal ring in the axial direction of the rotating shaft so as to be in close contact with the external annular member. can.

In this case, the auxiliary seal chamber can be easily formed by the third seal ring and the external annular member, and the stable seal posture of the third seal ring can be set, so that the seal air during operation leaks to the atmosphere side. It can be reduced more effectively.

(5) A preferred embodiment of the present invention may be a configuration in which the external annular member is fixed to the shaft sealing box on the outward side in the axial direction away from the gas passage.

By doing so, the third seal ring and the external annular member can be easily added to the existing blower.

(6) In a preferred embodiment of the present invention, a motor for rotationally driving the rotating shaft is provided, and the casing and the motor can be integrally connected to each other.

In this case, a compact blower can be manufactured.

(7) A preferred embodiment of the present invention is an annular plate-shaped swing having a diameter larger than the inner peripheral diameter of the external annular member on the rotating shaft on the axially outer side of the external annular member. The board may be arranged.

With this configuration, the seal air leaking from the auxiliary seal chamber to the outside in the axial direction can be shaken off in the radial direction together with the surrounding dust by the shakeout plate, and the intrusion of dust to the motor side can be effectively suppressed. ..

(8) A preferred embodiment of the present invention is a casing in which a gas passage into which a part of the exhaust gas of a marine engine can be introduced and a shaft hole communicating with the gas passage are formed, and the shaft hole of the casing. Attached to a blower equipped with a rotary shaft rotatably inserted and an impeller supported by the rotary shaft and housed in the casing and introduced into the gas passage to recirculate the boosted EGR gas to the engine. An EGR blower sealing device that seals the shaft hole, the annular first and second sealing rings surrounding the rotating shaft in the vicinity of the shaft hole, and the first and second sealing rings. An annular shaft sealing box having an annular wall portion surrounding the annular wall portion and a pair of inner side wall portions integrally coupled to the annular wall portion on both sides in the axial direction of the rotating shaft, and the inside of the shaft sealing box in the gas passage or more. A high-pressure seal air is introduced into the main seal chamber, and the first and second seal rings are brought into close contact with the pair of inner side walls to form a main seal chamber to prevent the exhaust gas from leaking from the gas passage to the atmosphere side. It has a static pressure gas sealing means and an annular third sealing ring that surrounds the rotating shaft on the outward side in the axial direction away from the gas passage with respect to the shaft sealing box, from the main sealing chamber to the atmosphere side. The configuration may include a backup sealing means for forming an auxiliary sealing chamber that limits the leakage of sealing air.

With this configuration, the leakage of the exhaust gas in the blower from the gas passage side to the atmosphere side in the ship can be effectively suppressed by the pressurized seal air of the static pressure gas sealing means, and the amount of the seal air leaking to the atmosphere side can be effectively suppressed. It can be sufficiently reduced by the cooperation of the static pressure gas sealing means and the backup sealing means.

According to the present invention, it is possible to provide a blower capable of suppressing the power consumption of the seal air supply source, and at the same time, it is possible to provide a blower suitable for an EGR blower of a marine engine.

It is a schematic block diagram of the EGR system of the EGR blower which concerns on one Embodiment of this invention and a marine engine including it. It is an enlarged sectional view of the part near the shaft hole of the EGR blower which concerns on one Embodiment of this invention. It is a partially enlarged sectional view showing the M portion surrounded by the alternate long and short dash line in FIG. 2 in a further enlarged manner. It is a front view of the segment seal type seal ring in the EGR blower which concerns on one Embodiment of this invention. It is a block diagram of the segment seal type seal ring in the EGR blower which concerns on one Embodiment of this invention, and is the B arrow view in FIG. 4A. FIG. 3 is an enlarged cross-sectional view of a portion near a shaft hole of an EGR blower according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(One embodiment)
1 to 4B show a case where the blower according to the embodiment of the present invention is provided as an EGR blower in a power system equipped with an EGR device.

First, the configuration will be explained.

As shown in FIG. 1, the power system 100 of the present embodiment includes an engine 110, which is a multi-cylinder large two-stroke diesel engine, a turbocharger 120, and an EGR device 130. All are designed to be installed in the engine room of a ship (not shown).

The engine 110 is, for example, an electronically controlled high-output engine that can be used as the main engine of an ocean-going vessel. A fuel supply unit 102, an air supply receiver 103, an exhaust receiver 104, and the like are mounted on a multi-cylinder engine main body 101. Has the same configuration. Although it is intended for ships in this embodiment, the engine 110 can also be used as a stationary engine for operating a generator of a power plant, for example, when it is not for ships.

The multi-cylinder engine body 101 is provided with a plurality of cylinders 111. Each of these plurality of cylinders 111 is connected to the air supply receiver 103 via the scavenging port 113, and can be exhausted into the exhaust receiver 104 when the corresponding exhaust valve 114 is opened. In each cylinder 111, when the air compressed above the ignition point by the piston 112 after being taken in by scavenging and the fuel injected into the air burn, the combustion gas expands and the piston 112 is driven. At the same time, exhaust gas is generated. Then, the exhaust gas from each cylinder 111 is intermittently sent out into the exhaust receiver 104.

The fuel supply unit 102 pumps and pressurizes the marine diesel fuel purified by the fuel purifier, and when the fuel valve for each cylinder opens at a predetermined timing, the fuel is injected and supplied into each cylinder 111 of the engine body 101. You can do it.

The air supply receiver 103 is a compressed air reservoir (scavenging receiver) for performing a scavenging action of filling the combustion gas in each cylinder 111 of the engine body 101 with new air while discharging the combustion gas, and the exhaust receiver 104 is an engine. It is an exhaust reservoir that can supply most of the exhaust gas from each cylinder of the main body 101 to the turbocharger 120 side while accumulating and storing it.

The turbocharger 120 includes a turbine 121 driven by exhaust gas supplied from the exhaust receiver 104 side, and a compressor 122 that introduces and compresses outside air when driven by the turbine 121 and supplies it into the air supply receiver 103. Have.

The EGR device 130 takes in a part of the exhaust gas from the exhaust receiver 104 into the recirculation path Le to the air supply receiver 103 side to purify the wet scrubber unit 131, and the exhaust gas purified by the scrubber unit 131 (hereinafter referred to as “exhaust gas”). The EGR cooler 132 that cools the EGR gas) by heat exchange and the EGR gas cooled by the EGR cooler 132 can be supplied into the supercharging passage Lc from the compressor 122 of the turbocharger 120 to the air supply receiver 103. It is configured to include an EGR blower 133 that boosts the pressure to a pressure level.

The wet scrubber unit 131 sprays, for example, droplets capable of neutralizing sulfur oxides in the exhaust gas taken into the recirculation path Le, and absorbs soot particles in the exhaust gas and the recirculation path. Consists of a scrubber that can make the size of the droplets suitable for the primary cooling of the recirculated exhaust gas in Le, and a mist catcher that collects the droplets after purification of the recirculated exhaust gas on the inner bottom side of the scrubber. Has been done.

Although not shown in detail, the EGR cooler 132 is a heat exchanger having an EGR gas passage through which the purified and primary cooled EGR gas passes through the scrubber unit 131 and a cooling water passage through which cooling water from the outside is passed. It is composed of a heat exchanger capable of cooling (secondary cooling) the EGR gas by heat exchange between fluids passing through both passages.

The EGR blower 133 is rotatable in the casing 10 in which the gas passage 11 into which the EGR gas that has passed through the EGR cooler 132 is introduced and the shaft hole 12 communicating with the gas passage 11 are formed, and the shaft hole 12 of the casing 10. It includes a rotating shaft 21 that has been inserted, an impeller 22 that is supported by the rotating shaft 21 and housed in a casing 10, and a sealing device 30 that seals the shaft hole 12.

Further, as shown in FIG. 1, a motor 70 having an output shaft 71 for rotationally driving the rotary shaft 21 on the outer surface side (right side in FIG. 1) separated from the gas passage 11 of the casing 10 with respect to the shaft seal box 33. Is placed.

As shown in FIGS. 1 and 2, the gas passage 11 of the casing 10 opens to a large diameter on the left end side in FIG. 1 which is the outer end side of the casing 10, while the right side (inner side) in the same figure. It has an introduction passage 11a that extends inward in the axial direction of the rotation shaft 21 and has a diameter reduced inward, and a scroll passage 11b that surrounds the inner end of the introduction passage 11a. The casing 10 has an introduction port portion 11c that opens to a large diameter on the outer end side of the introduction passage 11a, and an outlet portion 11d that projects the downstream end of the scroll passage 11b to the outward side in the radial direction from the introduction port portion 11c. And have.

The casing 10 is a motor that forms the gas passage 11 and forms a shaft hole 12 at the center of the main body 13 that opens the motor mounting surface side and a substantially disk shape that closes the motor mounting surface side of the main body 13. It is composed of a mounting plate 14 and a plurality of bolts 15 that detachably fix the motor mounting plate 14 to the main body 13. A mounting bracket 73 for mounting the motor 70 is mounted on the motor mounting plate 14 of the casing 10, and a support bracket 74 for supporting the motor 70 from below is mounted on the back side of the casing 10. Then, the casing 10 and the case 72 of the motor 70 are integrally connected via the mounting bracket 73 and the support bracket 74.

Further, the rotary shaft 21 is a cylindrical body with a lid that can be connected to the output shaft 71 of the motor 70 so as to rotate integrally, and is fitted to the output shaft 71 of the motor 70 with a predetermined fitting pressure. A substantially cylindrical body 23 with a step to be fitted, a lid body 24 that is concentrically fitted to one end of the substantially cylindrical body 23 in the impeller 22 and one end thereof is closed, and a lid body 24 and an output shaft 71 of the motor 70. An annular spacer 25 that is interposed between the cylindrical body 23 and the lid 24 so that the substantially cylindrical body 23 and the lid body 24 can be positioned at predetermined positions in the axial direction with respect to the output shaft 71 of the motor 70, and the substantially cylindrical body 23 with respect to the output shaft 71 of the motor 70. It has a bolt 26 for integrally fastening and fixing the lid 24 and the spacer 25.

The impeller 22 supported by the rotating shaft 21 in the casing 10 has an inlet portion 22a close to the inner end portion of the introduction passage 11a in the gas passage 11 and an outlet portion that opens in the scroll passage 11b in the radial direction. It has a 22b and a plurality of blade portions 22c extending from the inlet portion 22a to the outlet portion 22b and separated from each other at equal angular intervals. The impeller 22 constitutes a centrifugal blower together with the casing 10 and the rotating shaft 21, and when the impeller 22 is rotationally driven by the motor 70 via the rotating shaft 21, the EGR gas introduced into the gas passage 11 of the casing 10 is used in the engine 110. The pressure is increased so that it can be recirculated.

As shown in FIG. 2, the sealing device 30 is interposed between the casing 10 and the rotating shaft 21 and closes the gap G around the rotating shaft 21 in the shaft hole 12.

The sealing device 30 comprises an

annular shaft

31 and 32 that surrounds the rotating shaft 21 near one end of the shaft hole 12 and an annular shaft that houses the first and second sealing rings 31 and 32. It is configured to include the sealing box 33. Further, as shown in FIGS. 2 and 3, the sealing device 30 includes a static pressure gas sealing means 40 and a backup sealing means 60.

The shaft seal box 33 is substantially orthogonal to the annular wall portion 33a having an annular inner peripheral surface shape surrounding the first and second seal rings 31 and 32 and the annular wall portion 33a on both sides in the axial direction of the rotating shaft 21. It has a pair of inner

side wall portions

33b and 33c that are integrally connected so as to be used.

Specifically, the shaft sealing box 33 forms a first annular body 34 fixed around the shaft hole 12 of the casing 10 by a plurality of bolts 33g on the outer surface side, and an inner side wall portion 33b on one side of the pair. The second annular body 35 bolted to the inner surface side (left end surface side in FIG. 2) of the first annular body 34 and the inner side of one of the pair while being integrally formed on the outer surface side of the first annular body 34. It is composed of a third annular body 36 that forms an inner side wall portion 33c on one side so as to face the wall portion 33b.

In the static pressure gas sealing means 40, a plurality of compression coil springs 41 are contracted at equal intervals (equal angular intervals) in the circumferential direction between the first and second seal rings 31 and 32 in the shaft sealing box 33. By urging the first and second seal rings 31 and 32 so as to be in close contact with the pair of inner

side wall portions

33b and 33c of the shaft seal box 33, an annular main seal chamber 42 is formed in the shaft seal box 33. is doing. In the main seal chamber 42, high-pressure seal air is introduced from the seal air (air for sealing) supply circuit 45 shown in FIG. 3 into the gas passage 11 and the shaft hole 12 of the casing 10. The leakage of exhaust gas from the gas passage 11 in the casing 10 to the atmosphere side can be suppressed.

As shown in FIG. 3, the seal air supply circuit 45 includes a check valve 46 and a pressure gauge (not shown) on the air supply passage 45h communicating with the seal air passage 34h formed in the first annular body 34 of the shaft seal box 33. It is composed of a pressure control unit 47 including a flow meter, a relief valve, a filter and the like, an on-off valve 48, and an air supply source 49 such as an air pump.

The pressure regulating unit 47 and the on-off valve 48 are controlled according to, for example, the rotation speed [rpm] of the engine 110, the load, the pressure in the gas passage 11, and the seal air supply circuit 45. By constantly supplying seal air into the main seal chamber 42 at a supply pressure higher than the pressure of the gap G in the shaft hole 12 communicating with the engine, EGR gas is discharged from the gas passage 11 in the casing 10 to the atmosphere side through the shaft hole 12. It is designed to constantly prevent leakage. Therefore, the supply pressure of the seal air is always higher than the atmospheric pressure, such as the outlet side pressure of the exhaust receiver 104, the back pressure from the turbine 121 side of the turbo supercharger 120, the inlet side pressure of the air supply receiver 103, and the turbo. When the pressure in the gas passage 11 (pressure on the back side of the impeller 22) rises according to any of the boost pressure from the compressor 122 side of the booster 120, the rotation speed [rpm] of the motor 70, and the like. It can be regulated to a pressure higher than that pressure. The supply pressure of the seal air may be gradually increased or decreased.

Of the first and second seal rings 31 and 32 of the static pressure gas sealing means 40, the second seal ring 32 on the atmosphere side includes a plurality of arcuate segment seal members 51 adjacent to each other in the circumferential direction and a plurality of these. It has a split seal structure composed of a garter spring 52 that elastically and integrally restrains the segment seal member 51 while urging the rotary shaft 21 side.

Further, in the present embodiment, not only the second seal ring 32 but also the first seal ring 31 close to the shaft hole 12 of the casing 10 has a plurality of arcuate segment seal members 51 adjacent to each other in the circumferential direction. It has a split seal structure composed of a garter spring 52 that elastically and integrally restrains the plurality of segment seal members 51 while urging them toward the rotating shaft 21.

Each of the plurality of segment seal members 51 of the first and second seal rings 31 and 32 has a pair of knock pin holes 51k having a predetermined angular interval on one side thereof, and a plurality of compression coil springs on the other side. It has a plurality of concave holding holes 51n capable of holding the end portion of 41. Further, the first seal ring 31 and the second seal ring 32 are opposite to each other so that the concave holding holes 51n and the knock pin holes 51k open in opposite directions in the axial direction of the rotating shaft 21. is set up.

Then, the plurality of segment seal members 51 spread in the axial direction and the radial direction and face the first facing surface 51a in the circumferential direction with the minute gap Ec separated from each other, and the sliding gap Ed spreads in the circumferential direction and the radial direction. A plurality of knock pins 33j on the shaft sealing box 33 side, which are arranged on the same circumference and are loosely fitted in a plurality of pairs of knock pin holes 51k so as to have a second facing surface 51b facing each other in the axial direction. It is guided on the rotating shaft 21 by 33k, and is urged by a garter spring 52 on the outer peripheral side on the outer peripheral surface of the rotating shaft 21 with a predetermined contact pressure.

Here, the minute gap Ec extending in the axial direction of the rotating shaft 21 is not covered at all on the outer peripheral surface side and the mutual facing side (concave holding hole 51n side) of the first and second seal rings 31 and 32. On the other hand, on the close surface side (knock pin hole 51k side) where the first and second seal rings 31 and 32 are in close contact with the pair of inner

side wall portions

33b and 33c, the first and second seal rings 31 and 32 are covered and narrowed by the pair of inner

side wall portions

33b and 33c. ing.

Further, on both sides of the first and second seal rings 31 and 32 in the axial direction, the circumferential position of the minute gap Ec extending in the axial direction of the rotating shaft 21 is displaced, and the sliding gap Ed extending in the circumferential direction is As shown in FIG. 4B, the first and second seal rings 31 and 32 are bent in the opposite direction between the minute gaps Ec on both sides in the axial direction, and are narrower than the minute gaps Ec on both sides in the axial direction. There is. These minute gaps Ec and minute gaps Ec form an orifice-shaped leak passage 51e having a large pressure loss.

The backup sealing means 60 is arranged on the outer surface side (right end side in FIG. 2) of the shaft sealing box 33 separated from the gas passage 11 of the casing 10, and has an annular third sealing ring 61 surrounding the rotating shaft 21. An external annular member 63 provided so as to cover the third seal ring 61 from the radial outside and the axial outside, and detachably fixed to the first annular body 34 of the shaft sealing box 33 by a bolt 66, and a third. An elastic member 64 such as a compression coil spring for urging the seal ring 61 of No. 3 to the outer side in the axial direction of the rotating shaft 21 so as to be in close contact with the inner side wall portion 63a of the external annular member 63, and the first shaft sealing box 33. It has a hermetic seal 65 made of a rubber elastic ring interposed between the annular body 34 and the external annular member 63.

The backup sealing means 60 forms an auxiliary sealing chamber 62 between the shaft sealing box 33 and the external annular member 63 to limit the leakage of the sealing air from the main sealing chamber 42 of the static pressure gas sealing means 40 to the atmosphere side. is doing.

Further, although the details of the third seal ring 61 of the backup seal means 60 are not shown in detail, a plurality of circles adjacent to each other in the circumferential direction are substantially similar to the second seal ring 32 on the atmosphere side of the static pressure gas seal means 40. It has a split seal structure composed of an arc-shaped segment seal member (equivalent to 51) and a garter spring (equivalent to 52) that elastically and integrally restrains these plurality of segment seal members while urging them toward the rotating shaft 21 side. is doing.

The plurality of segment seal members of the third seal ring 61 are also pressured by the plurality of segment seal members, similarly to the plurality of arcuate segment seal members 51 of the second seal ring 32 shown in FIGS. 4A and 4B. It has an orifice-shaped leak passage (indicated by reference numeral 61e in parentheses in the figure) having a large loss.

In such a sealing device 30 of the present embodiment, when the supply pressure of the sealing air to the main sealing chamber 42 is a pressure P1 [MPa] sufficiently higher than the atmospheric pressure, the leakage passage 51e of the second sealing ring 32 The condition that the leaking seal air becomes a so-called choked flow ((P2 + 0.1) / (P1 + 0.1) is a critical pressure ratio b or less) can be satisfied. In this case, when the seal air leaks from the main seal chamber 42 to the auxiliary seal chamber 62 side, a large pressure loss corresponding to the upstream pressure P1 is generated by the second seal ring 32, and the auxiliary seal chamber 42 to the auxiliary seal chamber 42. The mass flow rate of the seal air leaking to the 62 side is effectively limited.

Further, in this case, the pressure P2 in the auxiliary seal chamber 62 becomes a predetermined pressure or less, which is sufficiently smaller than the pressure P1 of the seal air in the main seal chamber 42, although the pressure is equal to or higher than the atmospheric pressure, and the upstream pressure of the third seal ring 61 is applied. The pressure ratio of the atmospheric pressure P3 [MPa], which is the downstream pressure, becomes relatively large with respect to the pressure P2 in the auxiliary seal chamber 62. Therefore, the condition that the seal air leaking from the orifice-shaped leak passage 61e of the third seal ring 61 becomes a so-called subsonic flow ((P3 + 0.1) / (P2 + 0.1) is larger than the critical pressure ratio b) is satisfied. obtain. Therefore, the mass flow rate of the seal air leaking from the auxiliary seal chamber 62 to the atmosphere side depends on both the pressure P2 and the atmospheric pressure P3 in the auxiliary seal chamber 62, and is sufficiently (auxiliary seal) by the third seal ring 61. The flow rate is limited to a smaller flow rate than when the inside of the chamber 62 becomes a choked flow at a high pressure of about P1.

On the other hand, when the supply pressure of the seal air to the main seal chamber 42 is higher than the atmospheric pressure but not so high, or at the pressure P1 where the supply pressure of the seal air to the main seal chamber 42 is sufficiently higher than the atmospheric pressure. However, when the pressure P2 in the auxiliary seal chamber 62 is relatively high, the condition that the seal air leaking from the orifice-shaped leak passage 51e of the second seal ring 32 becomes a subsonic flow ((P2 + 0.1) / (P1 + 0.). 1) is larger than the critical pressure ratio b) can be established.

In this case, the mass flow rate of the seal air leaking from the main seal chamber 42 to the auxiliary seal chamber 62 side depends on both the pressure P1 in the main seal chamber 42 and the pressure P2 in the auxiliary seal chamber 62. , The second seal ring 32 is sufficiently limited (to a smaller flow rate than in the case of choked flow).

As described above, the EGR blower 133 having the sealing device 30 of the present embodiment cooperates with the static pressure gas sealing means 40 and the backup sealing means 60 of the sealing device 30 to move to the atmosphere side through the shaft hole 12 of the casing 10. The amount of leaked seal air is sufficiently reduced.

As shown in FIG. 2, on the rotating shaft 21 located on the outer side in the axial direction from the external annular member 63 with respect to the casing 10, a ring plate having a diameter larger than the inner peripheral diameter of the external annular member 63 is formed. The shake plate 81 of the above is arranged. The shake-off plate 81 projects in the shape of a baffle plate substantially perpendicular to the outer peripheral surface of the rotary shaft 21, and radiates the seal air leaking from the auxiliary seal chamber 62 in the axial direction of the rotary shaft 21 together with surrounding dust and the like. By swinging it off in the direction, the intrusion of dust into the motor 70 side is suppressed.

By the way, in the turbocharger 120, when the turbine 121 is rotationally driven by the exhaust energy from the exhaust receiver 104 of the engine 110, the fresh air (air from the outside) and the EGR gas taken into the compressor 122 are pressurized. It is supercharged to the supply air receiver 103 side of the engine 110 with a predetermined supercharging pressure. The turbocharger 120 is configured to control the intake of exhaust gas into the turbine 121 by a variable nozzle function, bypass the exhaust gas, and control the bypass flow rate according to preset operating conditions. May be good. In that case, the energy of the exhaust gas from the exhaust receiver 104 may change depending on the operating state of the engine 110, whereas the supercharging pressure by the turbocharger 120 can be suitably controlled.

Further, the EGR device 130 selectively limits its operation by narrowing or shutting off the recirculation path Le according to the engine speed [rpm] or according to preset operating conditions. Can be. By doing so, it is possible to selectively limit the emission of NOx according to the engine speed [rpm] and the navigation area of the ship.

Next, the action will be explained.

In the EGR blower 133 provided with the sealing device 30 of the present embodiment configured as described above, the static pressure gas seal is formed in the main sealing chamber 42 formed between the first and second sealing rings 31 and 32. By introducing the seal air having a higher pressure than the inside of the shaft hole 12 communicating with the gas passage 11 by the means 40, it is surely prevented that the exhaust gas in the EGR blower 133 leaks from the gas passage 11 side to the atmosphere side. ..

Further, since the front-rear differential pressure of the second seal ring 32 is suppressed by the third seal ring 61 of the backup sealing means 60 and the front-rear differential pressure of the third seal ring 61 is also suppressed, each seal ring 32, The leakage flow rate of the seal air to the atmosphere side, which can change depending on the front-rear differential pressure of 61, is effectively limited by the cooperation of the static pressure gas sealing means 40 and the backup sealing means 60.

Moreover, in the present embodiment, a gas passage 11 into which a part of the exhaust gas of the engine 110 can be introduced is formed in the casing 10, and the rotating shaft 21 is inserted into the shaft hole 12 communicating with the gas passage 11 to be an impeller. Since the blower configuration is such that the 22 is supported and the exhaust gas introduced into the gas passage 11 is recirculated to the engine 110 so as to be recirculated, the exhaust gas of the engine 110 is recirculated in order to reduce the emission amount of NOx and the like. It is suitable for the EGR blower 133 that can be used.

Further, in the present embodiment, at least the second seal ring 32 on the atmosphere side of the first and second seal rings 31 and 32 is composed of a plurality of arcuate segment seal members 51, so that a plurality of seal rings 32 are formed. Depending on the shape of the inner peripheral surface and the shape of the end of the segment seal member 51, the minute gaps Ec, Ed, etc. between them can be set to an appropriate shape and size, and the seal air passing through the minute gap of the second seal ring 32 can be set. The leakage flow rate and the front-rear differential pressure of the second seal ring 32 can be stably secured.

In addition, in the present embodiment, the backup seal means 60 covers the third seal ring 61 from the radial outside and the axial outside, and the third seal ring 61 covers the external annular member 63. Since it has an elastic member 64 that urges the rotary shaft 21 in the axial direction so as to be in close contact with the third seal ring 61, the auxiliary seal chamber 62 can be easily formed by the third seal ring 61 and the external annular member 63, and the auxiliary seal chamber 62 can be easily formed. The stable sealing posture of the sealing ring 61 of 3 can be set, and the leakage of the sealing air during operation to the atmosphere side can be reduced more effectively.

Further, in the present embodiment, since the external annular member 63 is detachably coupled to the shaft sealing box 33 on the outward side in the axial direction separated from the gas passage 11, a third seal ring is attached to the existing blower. 61 and the external annular member 63 can be easily added.

Further, in a preferred embodiment of the present invention, a motor 70 for rotationally driving the rotating shaft 21 is arranged on the outward side in the axial direction separated from the gas passage 11 with respect to the shaft sealing box 33, and the casing 10 and the case of the motor 70 are arranged. Since the 72 is integrally connected, a compact EGR blower 133 can be manufactured.

In addition, in the present embodiment, the inner peripheral diameter of the external annular member 63 (hole diameter (2R1) corresponding to the radius R1 in FIG. 2) is on the rotating shaft 21 axially outside the external annular member 63. Since a larger diameter annular plate-shaped shake-off plate 81 is arranged, the seal air leaking outward from the auxiliary seal chamber 62 in the axial direction is shaken off by the shake-off plate 81 in the outward radiation direction together with surrounding dust and the like. It is possible to effectively suppress the intrusion of dust into the motor 70 side.

As described above, in the present embodiment, the mechanical sealing type sealing device 30 that closes the shaft hole 12 of the EGR blower 133 is an annular first and second sealing ring that surrounds the rotating shaft 21 in the vicinity of the shaft hole 12. A pair of inner side wall portions 33b that are integrally coupled to the annular wall portions 33a surrounding the first and second seal rings 31 and 32 and the annular wall portions 33a on both sides of the rotating shaft 21 in the axial direction. An annular shaft seal box 33 having 33c, and a pair of inner side wall portions 33b, which introduce high-pressure seal air into the shaft seal box 33 above the inside of the gas passage 11 and the first and second seal rings 31 and 32. A static pressure gas sealing means 40 that forms a main seal chamber 42 in close contact with 33c to prevent leakage of exhaust gas from the gas passage 11 to the atmosphere side, and a shaft sealing box 33 that is separated from the gas passage 11 in the non-axial direction. It has an annular third seal ring 61 that surrounds the rotating shaft 21 on the side, and includes a backup seal means 60 that forms an auxiliary seal chamber 62 that limits the leakage of seal air from the main seal chamber 42 to the atmosphere side. It is configured to be.

Therefore, the exhaust gas in the EGR blower 133 can be effectively suppressed from leaking from the gas passage 11 side to the atmosphere side in the ship by the pressurized seal air of the static pressure gas sealing means 40, and the seal air leaks to the atmosphere side. The amount can be sufficiently reduced by the cooperation of the static pressure gas sealing means 40 and the backup sealing means 60.

In the EGR blower 133 according to the above-described embodiment, the rotary shaft 21 is integrally fastened to the output shaft 71 of the motor 70, but as shown in FIG. 5, the rotary shaft 21 is the motor 70. In addition to the substantially cylindrical body 23 that is integrally fastened to the output shaft 71 of the above, a rotary sleeve 27 dedicated to the seal, which is fixed to prevent rotation on the outer peripheral surface of the substantially cylindrical body 23, is provided. It is also possible to provide a surface treated portion 27a that forms a sliding surface having a small frictional resistance with the seal rings 31, 32, and 61 and having excellent wear resistance.

Further, in the above-described embodiment, the seal rings 31, 32, and 61 all have the same split seal structure, but the first seal ring 31 or the third seal ring 61 is the second seal ring 32. Needless to say, the seal structure may be different from that of the above. Further, although the engine 110 is used for a ship in one embodiment, the present invention is a large engine other than that for a ship, for example, a stationary engine for operating a generator, and the generator, the stationary engine, and the like are used. It can also be applied when it is installed in a relatively narrow space.

As described above, the present invention can provide a blower capable of suppressing the power consumption of the seal air supply source, and at the same time, can provide a blower suitable for an EGR blower of a marine engine. Therefore, it is useful for all blowers suitable for an exhaust gas recirculation system of a large engine.

10 Casing 11 Gas passage 12 Shaft hole 21 Rotating shaft 22 Impeller 30 Sealing device 31 First seal ring 32 Second seal ring 33 Shaft sealing box 33a

Circular wall part

33b, 33c Pair of inner side wall parts 34h Sealing air passage 40 Static pressure Gas sealing means 42 Main sealing chamber 45 Sealing air supply circuit 51 Segment sealing member 51a First facing surface 51b

Second facing surface

51e, 61e Leakage passage 60 Backup sealing means 61 Third sealing ring 62 Auxiliary sealing chamber 63 External annular member 63a Inner side wall part 64 Elastic member 65 Hermetic seal 70 Motor 71 Output shaft 81 Shake plate 100 Power system 103 Air supply receiver 104 Exhaust receiver 110 Engine 120 Turbo supercharger 130 EGR device 133 EGR Blower Ec Micro gap Ed Sliding gap Lc supercharging passage Le recirculation path P1 pressure (pressure in the main seal chamber)
P2 pressure (pressure in the auxiliary seal chamber)
P3 atmospheric pressure

Claims

A casing in which a gas passage and a shaft hole communicating with the gas passage are formed, a rotating shaft rotatably inserted into the shaft hole of the casing, and an impeller supported by the rotating shaft and housed in the casing. And a blower provided with a sealing device for sealing the shaft hole.
The sealing device
An annular first and second seal ring surrounding the rotating shaft in the vicinity of the shaft hole,
An annular shaft seal box having an annular wall portion surrounding the first and second seal rings and a pair of inner side wall portions integrally coupled to the annular wall portion on both sides of the axis of rotation in the axial direction.
A main seal chamber is formed in the shaft seal box in which a higher pressure seal air is introduced than in the gas passage and the first and second seal rings are brought into close contact with the pair of inner side walls, and the main seal chamber is formed from the gas passage. A static pressure gas sealing means for preventing the exhaust gas from leaking to the atmosphere side,
Auxiliary to limit the leakage of seal air from the main seal chamber to the atmosphere side by having an annular third seal ring surrounding the rotating shaft on the outward side in the axial direction away from the gas passage with respect to the shaft seal box. A blower comprising a backup sealing means, which forms a sealing chamber.
The casing is formed with the gas passage into which a part of the exhaust gas of the engine can be introduced and the shaft hole communicating with the gas passage.
The blower according to claim 1, wherein the impeller recirculates the exhaust gas introduced into the gas passage and boosted to the engine.
Of the first and second seal rings, at least the second seal ring on the atmospheric side is composed of a plurality of arcuate segment seal members adjacent to each other in the circumferential direction.
The plurality of segment seal members have a first facing surface that spreads in the axial direction and the radial direction and faces each other in the circumferential direction, and a second facing surface that spreads in the circumferential direction and the radial direction and faces each other in the axial direction. The blower according to claim 1 or 2, wherein the blower is characterized by the above.
The backup sealing means includes an external annular member that covers the third sealing ring from the radial outside and the axial outside on the axially outer side separated from the gas passage with respect to the shaft sealing box. The invention according to any one of claims 1 to 3, further comprising an elastic member for urging the seal ring of No. 3 in the axial direction of the rotating shaft so as to be in close contact with the external annular member. The blower described.
The blower according to claim 4, wherein the external annular member is fixed to the shaft sealing box on the outward side in the axial direction separated from the gas passage.
A motor for rotationally driving the rotating shaft is provided.
The blower according to claim 5, wherein the casing and the motor are integrally connected.
A ring-shaped swing plate having a diameter larger than the inner peripheral diameter of the external annular member is arranged on the rotating shaft on the outer side in the axial direction from the external annular member. The blower according to claim 6.
A casing in which a gas passage into which a part of the exhaust gas of the engine can be introduced and a shaft hole communicating with the gas passage are formed, a rotating shaft rotatably inserted into the shaft hole of the casing, and the rotating shaft. An EGR blower sealing device that is mounted on a blower equipped with an impeller that is supported, housed in the casing, introduced into the gas passage, and recirculated the boosted EGR gas to the engine, and seals the shaft hole. There,
An annular first and second seal ring surrounding the rotating shaft in the vicinity of the shaft hole,
An annular shaft seal box having an annular wall portion surrounding the first and second seal rings and a pair of inner side wall portions integrally coupled to the annular wall portion on both sides of the axis of rotation in the axial direction.
A main seal chamber is formed in the shaft seal box in which a higher pressure seal air is introduced than in the gas passage and the first and second seal rings are brought into close contact with the pair of inner side walls, and the main seal chamber is formed from the gas passage. A static pressure gas sealing means for preventing the exhaust gas from leaking to the atmosphere side,
Auxiliary to limit the leakage of seal air from the main seal chamber to the atmosphere side by having an annular third seal ring surrounding the rotating shaft on the outward side in the axial direction away from the gas passage with respect to the shaft seal box. A blower sealing device comprising a backup sealing means for forming a sealing chamber.