JP6611621B2 - Shot ball collection device - Google Patents

Description

  The present disclosure relates to a shot ball collection device that collects shot balls for shot cleaning.

  In the waste treatment facility, a boiler is installed in order to recover the combustion heat of the waste as steam and use it for power generation. In the boiler, when dust adheres to the heat transfer tube, the heat exchange efficiency is lowered. Therefore, boiler dust removal technology is important for maximizing power generation. As the dust removal technique, conventionally, a soot blower system is known in which a fluid such as steam or compressed air is jetted to blow away dust adhering to the heat transfer tube surface. However, in the case of the soot blower system, there is a problem that the cost is increased due to consumption of the fluid, and the steam recovery rate is reduced because the steam is used.

  The present inventors have realized a shot cleaning system as a dust removal technique that replaces the soot blower system. In the shot cleaning method, steel balls, which are shot balls, are sprayed from the upper part of the heat transfer tube, and the free-falling steel balls collide with the heat transfer tube, so that the dust on the heat transfer tube is removed. Then, the steel balls and dust discharged from the boiler are separated and collected, and the collected steel balls are reused as shot balls. For example, in the steel ball recovery apparatus described in Patent Document 1, two sieve meshes having different sizes are provided, dust is dropped from the fine sieve on the upstream side to the dust chute, and the steel balls are removed from the coarse sieve on the downstream side. The steel balls and dust are separated and recovered by dropping them onto the chute. The steel balls are then dropped and stored in a steel ball tank (shot ball tank), intermittently cut out of the steel ball recovery device via a rotary valve for cutting out the steel balls, and the high pressure from the steel ball transport blower. It is conveyed to the boiler by air and reused as a shot ball.

JP 2010-216722 A

  However, in the method of separating steel balls and dust using sieves having different sizes described in Patent Document 1, the dust does not fall entirely from the fine sieve to the dust chute, but enters the steel ball chute from the coarse sieve. There is a risk of it. In particular, when a large amount of dust discharged from the boiler is supplied to the steel ball recovery device in a short period of time, a part of the dust moves to the coarse sieve that is the next sieve of the fine sieve, and from the coarse sieve It may invade the steel ball chute. Further, particularly fine dust among the dusts floats above the mesh by receiving an air current, and then settles to the coarse sieve and may enter the steel ball chute. Furthermore, the dust adhering to cover the steel ball may enter the steel ball chute from the coarse sieve together with the steel ball. The dust that has entered the steel ball chute in this way falls into a steel ball tank provided below the steel ball chute and stays in the steel ball tank.

  Here, although the rotary valve for cutting out the steel ball has a sealing function, it is difficult to completely block the air due to the structure, and a part of the high-pressure air from the steel ball transfer blower is used as leak air. It will flow to the tank side. A steel ball with a high specific gravity reaches the rotary valve without being affected by the air flow based on the leak air, while a dust with a low specific gravity is prevented from descending to the rotary valve by the air current flowing through the gap between the steel balls. There is a case. As a result, dust accumulates inside the steel ball tank, and as a result, the inside of the steel ball tank is filled with dust, hindering the descent of the steel ball itself, the steel ball is suspended from the shelf, and the steel ball tank is blocked. ing.

  Therefore, an object of the present disclosure is to provide a shot ball collection device that can suppress blockage of the shot ball tank.

  The shot ball recovery device according to the present disclosure includes a shot ball for shot cleaning sprayed in a boiler, and a sieve unit for discharging dust removed from a heat transfer tube of the boiler by spraying the shot ball, through a sieve. A shot ball chute that sends the shot ball discharged from the sieve part downward, a shot ball tank that stores the shot ball sent by the shot ball chute below the shot ball chute, and dust discharged from the sieve part A dust chute that feeds the outside, an opening formed between the shot ball chute and the dust chute, and an air flow that forms an air flow from the path of the shot ball toward the shot ball tank to the dust chute through the opening. A forming part.

  According to the shot ball collecting apparatus according to the present disclosure, the air flow forming unit forms an air flow from the shot ball path side toward the shot ball tank to the dust chute through the opening. As described above, since it is difficult to completely separate the shot sphere and dust discharged from the boiler, the dust that has entered the shot sphere tank through the shot sphere chute accumulates and the shot sphere tank is blocked. May occur. In this regard, in the shot ball collection device according to the present disclosure, an air flow is formed from the shot ball path side toward the shot ball tank to the dust chute through the opening, and therefore the dust flowing toward the shot ball tank is dusted by the air flow. It becomes easy to guide in the chute direction. As a result, it is possible to suppress the dust discharged to the shot ball chute without being properly separated from entering the shot ball tank. As described above, according to the present disclosure, accumulation of dust inside the shot ball tank can be suppressed, and blockage of the shot ball tank can be suppressed.

  The air flow forming unit may include a partition plate that partitions the internal space of the shot ball chute into a first space that guides the rising air flow to the opening and a second space that guides the shot ball downward. The shot ball goes from the shot ball chute to the lower shot ball tank, and the updraft flows from the shot ball tank to the upper shot ball chute. End up. In this case, a part of the airflow also flows on the shot ball chute side, and this flow weakens the ascending airflow (airflow toward the dust chute), and there is a possibility that the ascending airflow velocity may decrease. However, it is possible to suppress the ascending air current from weakening by arranging the partition plates so that the space vector for guiding the ascending air current to the opening does not interfere with the space for guiding the shot sphere downward.

  A third space is formed in the internal space of the shot ball chute through which airflow rising toward the first space passes. The shot ball chute has a guide wall that guides the shot ball from the second space to the third space. You may do it. Since the shot sphere is guided from the second space to the third space by the guide wall, the shot sphere and dust moving downward in the second space are exposed to the rising air current in the third space. Thereby, the dust that has moved downward in the second space can be appropriately guided in the dust chute direction by the rising airflow.

  The partition plate may be provided such that the first space is positioned on a linear extension of the airflow passing through the third space. As a result, the updraft in the first space is guided to the opening without changing the velocity vector, and dust can be put on the airflow and guided appropriately in the dust chute direction.

  The apparatus may further include a gas supply unit that supplies gas, and the airflow forming unit may form an airflow including the gas supplied from the gas supply unit. That is, a gas supply unit that supplies gas for forming an airflow may be further provided, and the airflow may be formed in the airflow forming unit. By supplying the gas from the gas supply unit, an optimal air flow can be formed by the air flow forming unit.

  The gas supply unit may include a cooling gas supply unit that supplies a cooling gas into the shot ball tank. By supplying the cooling gas into the shot sphere tank, the exhaust gas passes through the air flow forming section, and an upward air flow from the shot sphere tank can be easily generated.

  A first rotor that quantitatively cuts shot spheres stored in a shot sphere tank, and a shot sphere cut by the first rotor is discharged downstream of the first rotor while suppressing leakage against pressure on the discharge port side. You may further provide the 2nd rotor, the casing which accommodates a 1st rotor and a 2nd rotor, and the exhaust pressure pipe which connects the inside of a casing and the inside of a dust chute. Since the inside of the casing communicates with the inside of the dust chute via the exhaust pressure pipe, at least a part of the leak air from the second rotor side flows into the exhaust pressure pipe from the casing and is guided to the dust chute. As a result, leak air flowing from the second rotor side to the shot ball tank can be reduced. When dust has entered the shot ball tank, leak air from the second rotor side flows into the shot ball tank from the inlet of the first rotor, and this airflow interferes with dust extraction from the first rotor. However, dust accumulates inside the shot ball tank, and the shot ball tank may be blocked. In this respect, most of the leak air from the second rotor side flows into the exhaust pressure pipe, so that the leak air flowing to the shot ball tank side can be reduced, and the inflowing dust is cut out from the first rotor, The accumulation of dust can be suppressed, and the above-described blockage of the shot tank can be further suppressed.

  The exhaust pressure pipe may be connected to a path from the first rotor to the second rotor in the casing. Upstream from the first rotor, it is difficult to draw out the leak air properly because the shot ball before cutting is full. On the other hand, downstream of the second rotor, the air short-passes, so that it is not suitable as a position for extracting leaked air. In this regard, leak air can be appropriately induced by connecting a pressure reducing pipe to the space of the path from the first rotor to the second rotor.

  The first rotor is arranged around the rotation center and has a plurality of first pockets that can each accommodate a shot ball, and the second rotor is arranged around the rotation center and each of a plurality of second pockets that can accommodate a shot ball. The gap between the first rotor and the casing may be larger than the gap between the second rotor and the casing, and the volume of the second pocket may be larger than the volume of the first pocket. By making the gap between the first rotor and the casing relatively large, it is possible to prevent the shot ball from being bitten between the first rotor and the casing. Moreover, it can suppress that leak air becomes excessive by making the clearance gap between a 2nd rotor and a casing small enough. Furthermore, since the volume of the second pocket is made larger than the first pocket volume, the shot ball cut out from the first rotor is not filled in the second rotor. Thereby, also in the 2nd rotor by which the clearance gap between the casings was made small, it can suppress that a shot ball bites between the casings.

  According to the present disclosure, blockage of the shot ball tank can be suppressed.

It is the figure which showed the shot cleaning system typically. It is a longitudinal cross-sectional view which shows a steel ball collection | recovery apparatus. It is a longitudinal cross-sectional view which shows the detail of a steel ball cutting device. It is explanatory drawing for demonstrating the detail of a guide plate. It is a longitudinal cross-sectional view which shows the steel ball collection | recovery apparatus concerning a comparative example. It is a longitudinal cross-sectional view which shows the steel ball collection | recovery apparatus which concerns on a modification. It is a longitudinal cross-sectional view which shows the steel ball collection | recovery apparatus which concerns on a modification. It is a longitudinal cross-sectional view which shows the steel ball collection | recovery apparatus which concerns on a modification.

  Hereinafter, embodiments will be described in detail with reference to the drawings. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and redundant description is omitted.

[Shot cleaning system]
First, an outline of the shot cleaning system 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram schematically showing the shot cleaning system 1.

  The shot cleaning system 1 is applied to, for example, a boiler 50 that recovers high-temperature gas as steam and generates power. The shot cleaning system 1 removes the powdery dust 70 adhering to the heat transfer tube by spraying steel balls 60 (shot balls) on the heat transfer tube of the boiler 50. In the present embodiment, the boiler 50 will be described as recovering high-temperature gas generated by combustion of waste in a waste melting furnace (not shown) and generating electric power.

  As shown in FIG. 1, the high-temperature gas generated by the combustion of waste reaches 900 ° C. to 1000 ° C. and flows into the boiler 50. The hot gas flows downward while being cooled in the radiant cooling chamber 50a in the boiler 50, and reverses and flows upward at the lower end of the radiant cooling chamber 50a. Then, the high-temperature gas sequentially passes through the superheater 50b, the evaporator 50c, and the economizer 50d, and is discharged from the upper part of the boiler 50 as exhaust gas after heat recovery. The shot cleaning system 1 spreads the steel balls 60 on the heat transfer tubes of the superheater 50b, the evaporator 50c, and the economizer 50d described above, and removes the dust 70 attached to the heat transfer tubes.

  The shot cleaning system 1 includes a steel ball dispersion device 2 and a steel ball collection device 3 (shot ball collection device).

  The steel ball dispersing device 2 is provided above the economizer 50d. The steel ball dispersing device 2 collides with a steel ball jet nozzle 21 that jets a steel ball 60 sent by airflow conveyance (details will be described later) into the boiler 50, and a steel ball 60 jetted from the steel ball jet nozzle 21. And a collision plate 22 to be operated. The collision plate 22 includes, for example, a horizontal rotation shaft 22a orthogonal to the ejection direction of the steel ball 60, and a plate portion 22b that can rotate around the horizontal rotation shaft 22a. The plate portion 22b has a variable collision angle with respect to the steel ball 60 about the horizontal rotation shaft 22a, for example, by a motor (not shown). As shown in FIG. 1, the steel ball 60 ejected from the steel ball ejection nozzle 21 collides with the collision plate 22 (more specifically, the plate portion 22b) and is dispersed and dropped onto the economizer 50d. By tilting the plate portion 22b of the collision plate 22, the dispersion in the ejection direction of the steel balls 60 becomes uniform. The steel balls 60 dispersed in the economizer 50d sequentially pass through the economizer 50d, the evaporator 50c, and the superheater 50b, and are collected together with the dust 70 that has been removed, at the bottom of the boiler 50. Below the boiler 50, a steel ball recovery device 3 for separating and recovering the steel balls 60 and dust 70 is provided.

  The steel ball collection device 3 collects the shot cleaning steel balls 60 dispersed in the boiler 50 in order to remove the dust 70 adhering to the heat transfer tubes. Since the steel ball recovery device 3 is connected to the casing of the boiler 50 via the supply chute 50h, it is not directly exposed to the high-temperature gas flow. Thus, the steel ball collection | recovery apparatus 3 is arrange | positioned in the position which is hard to receive the influence of the heat transfer from the hot gas which passes the boiler 50. FIG. The steel ball collection device 3 separates and collects the steel balls 60 and dust 70 and stores the steel balls 60 until the next cleaning starts. When the cleaning start timing comes, the steel ball collecting device 3 cuts out the stored steel balls 60 and feeds the transported air to the steel ball dispersing device 2 by feeding the carrier air.

[Steel ball collection device]
Next, the detail of the steel ball collection | recovery apparatus 3 is demonstrated with reference to FIG. FIG. 2 is a longitudinal sectional view showing the steel ball collection device 3.

  As shown in FIG. 2, the steel ball collection device 3 includes a sieve portion 31, a steel ball chute 32 (shot ball chute), a steel ball tank 33 (shot ball tank), a dust chute 34, and a lump chute. 35, a steel ball cutting device 36, and a steel ball transport blower 38 (shot ball transport blower). An opening 39 is formed between the steel ball chute 32 and the dust chute 34, and the steel ball chute 32 and the dust chute 34 communicate with each other in the horizontal direction through the opening 39.

  The sieve part 31 discharges the steel balls 60 and dust 70 discharged from the boiler 50 through a sieve. The dust 70 and the steel balls 60 collected by the boiler lower chute 50x are fed into the sieve portion 31 by the supply chute 50h. The sieve portion 31 includes a cylindrical trommel sieve 31a and a rectangular tubular casing 31b that accommodates the trommel sieve 31a. The trommel sieve 31a is cut off from the outside air by being accommodated in the casing 31b.

  The trommel sieve 31a rotates around a rotation shaft 31c that penetrates the casing 31b. Specifically, the trommel sieve 31a has a support pillar 31d extending from the inner surface in the direction of the rotation shaft 31c connected to the rotation shaft 31c, and one end of the rotation shaft 31c coupled to the rotation drive device 31e. It rotates when 31e drives. The other end of the rotating shaft 31c is supported by a bearing (not shown), for example. The trommel sieve 31a and the rotating shaft 31c may be inclined on the discharge side (downstream side) so that the dust 70 and the steel ball 60 can be easily fed, and a spiral guide vane is provided on the inner surface. It may be.

  The trommel sieve 31a has two sieve meshes having different sizes on the side surface. That is, the trommel sieve 31a has a fine sieve surface 31g on which the fine sieve 31f is formed and a coarse sieve surface 31i on which the coarse sieve 31h is formed. The fine sieve surface 31g is formed on the upstream side (supply chute 50h side) with respect to the coarse sieve surface 31i. Therefore, the dust 70 and the steel ball 60 fed into the sieve part 31 are first sieved by the fine sieve 31f. The casing 31b has a fine lower surface 31y as a lower surface facing the fine sieve surface 31g, and a coarse lower surface 31x as a lower surface facing the coarse sieve surface 31i. The fine lower surface 31y and the coarse lower surface 31x allow an object that has passed through the fine sieve 31f and the coarse sieve 31h to pass downward.

  The diameter of the fine sieve 31 f is made smaller than the diameter of the steel ball 60. For example, when a steel ball 60 having a diameter of 10 mm is used, the diameter of the fine sieve 31 f is about 5 mm. The dust 70 of 5 mm or less is discharged from the fine sieve 31 f and falls onto the dust chute 34. On the other hand, the steel ball 60 does not fall from the fine sieve 31f but moves to the downstream side (coarse sieve surface 31i side). The diameter of the coarse sieve 31 h is made larger than the diameter of the steel ball 60. For example, when a steel ball 60 with a diameter of 10 mm is used, the diameter of the coarse sieve 31 h is about 15 mm. The steel ball 60 is discharged from the coarse sieve 31 h and falls onto the steel ball chute 32. In addition, since the lump 75 (foreign matter) having a diameter larger than 15 mm may interfere with the biting of the steel ball cutting device 36 and the conveyance of the steel ball 60, it moves further to the downstream side in the trommel sieve 31a. It falls on the lump chute 35 from the downstream end. Hereinafter, the horizontal direction in which the fine sieve surface 31g and the coarse sieve surface 31i are adjacent to each other may be referred to as a horizontal direction, and the direction intersecting the horizontal direction and the vertical direction may be referred to as a depth direction.

  Note that it is difficult to completely separate the steel balls 60 and the dust 70 by the trommel sieve 31a (details will be described later). That is, ideally, all of the dust 70 falls from the fine sieve 31f to the dust chute 34, but in practice, a part of the dust 70 moves to the coarse sieve surface 31i and from the coarse sieve 31h to the steel ball chute. Falls to 32.

  The steel ball chute 32 feeds the steel ball 60 discharged from the coarse sieve 31 h of the sieve part 31 to the lower steel ball tank 33. As described above, since some dust 70 flows into the steel ball chute 32, the steel ball chute 32 also sends the dust 70 downward (in the direction of the steel ball tank 33).

  The steel ball chute 32 is located immediately below the rough lower surface 31x and is formed so that the inner cross-sectional area becomes smaller as it goes downward. The steel ball chute 32 has a square tubular exhaust pipe 32d (connection pipe) and an inlet nozzle 32e at its lower end, and is connected to the upper end of the steel ball tank 33 through the exhaust pipe 32d and the inlet nozzle 32e. ing. The exhaust pipe 32d and the inlet nozzle 32e are located below the substantially central portion (substantially central portion in the lateral direction and the depth direction) of the sieve portion 31.

  The steel ball chute 32 has four side surfaces 32a connected to the upper end (more specifically, the four sides of the upper end) of the exhaust pipe 32d. A pair of side surfaces (not shown) that face each other in the depth direction among the four side surfaces 32a extend from the upper end of the exhaust pipe 32d toward the rough lower surface 31x. Connected to almost the whole area. Of the pair of side surfaces 32b and 32c that face each other in the lateral direction, a first side surface 32b that is a side surface on the dust chute 34 side extends in the vertical direction from the upper end of the exhaust pipe 32d, and the inner side surface 34b of the dust chute 34 (for details) To be described later. That is, the first side surface 32 b of the steel ball chute 32 and the inner side surface 34 b of the dust chute 34 are connected immediately above the steel ball tank 33. Further, the second side surface 32c (guide wall) that is the side surface on the lump chute 35 side extends obliquely upward from the upper end of the exhaust pipe 32d toward the rough lower surface 31x, and at a substantially end portion on the downstream side of the rough lower surface 31x, The coarse lower surface 31x is connected to substantially the entire region in the depth direction.

  The exhaust pipe 32 d described above is connected to the lower end of the side surface 32 a, extends vertically downward toward the steel ball tank 33, and communicates with the steel ball tank 33. The exhaust pipe 32 d exhausts the air blown into the steel ball tank 33.

  The steel ball tank 33 stores the steel ball 60 sent out by the steel ball chute 32 below the steel ball chute 32. The steel ball tank 33 includes a straight barrel portion 33a having a constant inner cross-sectional area, and a tapered portion 33b that continues to the lower side of the straight barrel portion 33a and decreases in the inner cross-sectional area as it goes downward. The inner surface of the straight body portion 33a has a rectangular tube shape, and the inner surface of the tapered portion 33b has an inverted pyramid shape. The steel ball tank 33 is supplied with cooling air from an air source 90. The air source 90 supplies cooling air for cooling the steel balls 60 heated in the process of passing through the boiler 50 into the steel ball tank 33. The cooling air is blown into the steel ball tank 33 from the air source 90 via the cooling air pipe 91 and cools the steel ball 60 in the process of passing through the gap between the steel balls 60, and the steel ball chute 32, the sieve part 31 and discharged into the boiler 50 via the supply chute 50h and the like.

  The dust chute 34 sends out the dust 70 discharged from the fine sieve 31 f of the sieve part 31 to the outside of the steel ball collection device 3. The dust chute 34 is located directly below the fine lower surface 31y, and is formed so that the inner cross-sectional area becomes smaller as it goes downward. The dust 70 collected in the dust chute 34 is discharged to the outside of the steel ball collection device 3 by a rotary valve 34x having a sealing function. The rotary valve 34x is positioned below a substantially central portion in the lateral direction and depth direction of the fine lower surface 31y.

  The dust chute 34 has four side surfaces 34a, and a pair of side surfaces (not shown) of the side surfaces 34a facing each other in the depth direction extend from the lower end side of the dust chute 34 toward the fine lower surface 31y. At substantially both ends in the depth direction, it is connected to substantially the entire region in the lateral direction of the fine lower surface 31y. Of the pair of side surfaces 34b, 34c facing each other in the lateral direction, the inner side surface 34b, which is the side surface on the steel ball chute 32 side, extends from the lower end side of the dust chute 34 toward the upper end of the first side surface 32b of the steel ball chute 32. It is connected to the side surface 32b. Further, the outer side surface 34c, which is the other side surface of the pair of side surfaces 34b, 34c, extends from the lower end side of the dust chute 34 toward the fine lower surface 31y, and at the substantially end portion on the upstream side of the fine lower surface 31y, the fine lower surface 31y. Is connected to almost the entire area in the depth direction.

  The inner side surface 34b of the dust chute 34 and the first side surface 32b of the steel ball chute 32 are connected to each other below the lower surface (the coarse lower surface 31x and the fine lower surface 31y) of the sieve portion 31. An opening 39 is formed between the connection location and the lower surface of the sieve portion 31. The opening 39 is formed between the dust chute 34 and the steel ball chute 32 and allows the dust 70 to pass (details will be described later).

  The lump chute 35 sends out a lump 75 having a diameter larger than 15 mm, discharged from the downstream end of the trommel sieve 31a, to the outside of the steel ball collecting device 3. A double seal damper 35a is provided at the outlet of the lump chute 35 to ensure a sealing function.

  The steel ball cutting device 36 is disposed below the steel ball tank 33, cuts out the steel ball 60 discharged from the steel ball tank 33, and discharges it to the steel ball transport path 80 side. The steel ball cutting device 36 includes a first rotor 36a and a second rotor 36b that are two rotary valves having different diameters. The steel ball 60 cut out from the steel ball cutting device 36 is transported on the steel ball transport path 80 by the transport air from the steel ball transport blower 38 and sent to the steel ball dispersing device 2.

  Details of the steel ball cutting device 36 will be described with reference to FIG. FIG. 3 is a longitudinal sectional view showing details of the steel ball cutting device 36. The steel ball cutting device 36 includes a first rotor 36a, a second rotor 36b, and a casing 36c that houses the first rotor 36a and the second rotor 36b.

  The first rotor 36a and the second rotor 36b are each fixed to a rotation shaft (rotor shaft), have a sprocket (not shown), and the sprocket is connected to a rotation drive device 36r via a conduction chain 36l. And the 1st rotor 36a and the 2nd rotor 36b rotate by one rotation drive device 36r driving. The amount of steel ball 60 cut out by the first rotor 36a is controlled by the rotational speed of the first rotor 36a.

  The first rotor 36 a cuts out a predetermined amount of the steel ball 60 stored in the steel ball tank 33. Between the first rotor 36a and the casing 36c, a gap cl1 that is equal to or larger than the maximum diameter Ot of the steel ball 60 is formed to prevent biting. More specifically, a gap cl1 that is equal to or larger than the maximum diameter Ot of the steel ball 60 is provided between the inner surface of the inlet portion 36x that is the casing 36c on the inlet side of the steel ball 60 and the tip of the blade portion 36w of the first rotor 36a. Is formed.

  The first rotor 36 a has a plurality of pockets 36 s 1 (first pockets) that are arranged around the rotation center and can each accommodate the steel ball 60. The pockets 36s1 are provided between a plurality of blade portions 36w provided in the circumferential direction. The first rotor 36a rotates while filling the steel balls 60 in the pockets 36s1, and drops the steel balls 60 on the second rotor 36b disposed below.

  The second rotor 36b discharges the steel ball 60 cut out by the first rotor 36a to the steel ball conveying blower 38 side (see FIG. 2) downstream (downward) of the first rotor 36a. Between the second rotor 36b and the casing 36c, a minimum gap cl2 is formed in terms of manufacturing accuracy in order to suppress leakage from the high-pressure steel ball transport path 80. More specifically, a gap cl2 is formed between the inner surface of the outlet portion 36y that is the casing 36c on the outlet side of the steel ball 60 and the tip of the blade portion 36z of the second rotor 36b.

  The second rotor 36b has a plurality of pockets 36s2 (second pockets) arranged around the rotation center and capable of accommodating the steel balls 60, respectively. The pockets 36s2 are provided between the plurality of blade portions 36z provided in the circumferential direction. The pocket 36s2 has a larger volume than the pocket 36s1 of the first rotor 36a, and is, for example, about 2 to 3 times the volume of the pocket 36s1. For this reason, in the pocket 36s2 of the 2nd rotor 36b, since the steel ball dropped from the pocket 36s1 of the 1st rotor 36a rotates without being filled and is discharged, it can prevent biting.

  As described above, the second rotor 36b substantially blocks air because the gap cl2 with the outlet portion 36y is minimized. However, because of the structure of the second rotor 36b, it is difficult to completely block air, and a part of the high-pressure air from the steel ball transfer blower 38 flows into the upstream side as the leak air from the second rotor 36b. Such leak air moves upward in the casing 36 c and flows into the steel ball tank 33.

  The steel ball transport blower 38 air-transports the steel balls 60 discharged from the second rotor 36b of the steel ball cutting device 36 to the spraying position (steel ball dispersing device 2) on the boiler 50. The steel ball transport blower 38 transports the steel ball 60 on the steel ball transport path 80 by sending transport air (high pressure gas). The steel ball transport path 80 connects the steel ball collection device 3 and the steel ball dispersion device 2. For this reason, the steel ball 60 conveyed by the air flow from the steel ball conveying blower 38 flows into the steel ball dispersing device 2.

  Here, as described above, some of the dust 70 may flow into the steel ball chute 32 from the coarse sieve 31h (details will be described later). In this case, the dust 70 may enter the steel ball tank 33. There is. Air from the steel ball conveying blower 38 (leak air flowing upward) flows into the steel ball tank 33 via the steel ball cutting device 36. For this reason, if the dust 70 enters the steel ball tank 33, the flow of the dust 70 to the steel ball cutting device 36 side is hindered by the influence of the leak air, and the dust 70 accumulates in the steel ball tank 33. It becomes easy. As a result, the steel ball tank 33 may be blocked. In the present embodiment, the dust 70 is prevented from entering the steel ball tank 33 by forming an upward air flow from the steel ball tank 33 side to the dust chute 34 via the steel ball chute 32.

  In other words, the steel ball collection device 3 supplies an air flow forming unit 100 that forms an air flow from the path side of the steel ball 60 toward the steel ball tank 33 through the opening 39 to the dust chute 34 and air related to the generation of the air flow. And an air source 90 (gas supply unit). The airflow forming unit 100 includes a guide plate 37 (partition plate) and forms an airflow including air supplied from the air source 90.

  As described above, the air source 90 supplies cooling air for cooling the steel balls 60 into the steel ball tank 33. Since the inside of the steel ball collection device 3 is generally at the same pressure, the movement of the object inside the steel ball collection device 3 depends on the dynamic pressure of the fluid. Inside the steel ball tank 33, the cooling air supplied from the air source 90 is discharged from the inlet nozzle 32 e of the steel ball tank 33. Further, since the steel ball chute 32 and the dust chute 34 communicate with each other through the opening 39, the upward airflow becomes an airflow from the steel ball chute 32 through the opening 39 toward the dust chute 34 side. That is, when the air source 90 supplies cooling air to the steel ball tank 33, an air flow is generated from the steel ball tank 33 side through the opening 39 toward the dust chute 34.

  The guide plate 37 divides the internal space of the steel ball chute 32 into a first space S1 that guides the upward air flow from the steel ball tank 33 to the opening 39 and a second space S2 that guides the steel ball 60 downward. To do. The guide plate 37 is disposed on the steel ball chute 32. By restricting the path of the steel ball 60 from the steel ball chute 32 to the steel ball tank 33 to the second space S2, the path of the steel ball 60 (second The space S2) and the route of the updraft (first space S1) are partitioned. The guide plate 37 is provided so that the first space S <b> 1 is positioned vertically above a connection portion between the steel ball chute 32 (more specifically, the inlet nozzle 32 e) and the steel ball tank 33.

  The guide plate 37 extends from the boundary region between the steel ball chute 32 and the dust chute 34 toward the steel ball tank 33, forms a path (second space S2) of the steel ball 60 between the second side surface 32c, and An upward air flow path (first space S1) is formed between the first side surface 32b and the first side surface 32b. More specifically, the guide plate 37 extends from the boundary region between the steel ball chute 32 and the dust chute 34 toward the connection point between the exhaust pipe 32d and the second side surface 32c, and between the connection points, the steel ball 60 is provided. Forms an inflow portion 37x which is a space into which can flow.

  In the internal space of the steel ball chute 32 (more specifically, the internal space of the exhaust pipe 32d), a third space S3 through which an ascending air flow toward the first space S1 passes is formed. The steel balls 60 and dust 70 flowing downward in the second space S2 are guided to the inflow portion 37x by the second side surface 32c and flow into the third space S3. For this reason, the said steel ball 60 and the dust 70 will be exposed to the updraft which goes to 1st space S1 in 3rd space S3. The air related to the updraft reaches the first space S1 in a state including the dust 70 without changing the flow direction, that is, without receiving the resistance of the airflow. Since the guide plate 37 extends from the boundary region between the steel ball chute 32 and the dust chute 34, the air related to the upward airflow flows along the guide plate 37 toward the dust chute 34 adjacent to the steel ball chute 32. The minimum flow velocity at which the steel ball 60 floats is, for example, about 30 to 40 m / s, and the minimum flow velocity at which the dust 70 floats is, for example, about 5 m / s. Therefore, from the viewpoint of carrying out airflow classification of the steel balls 60 and the dust 70, it is preferable that the flow velocity of the air related to the rising airflow is about 5 to 30 m / s. The flow velocity is adjusted, for example, by adjusting the diameter of the exhaust pipe 32d described above.

  The guide plate 37 is formed, for example, by bending a single steel plate. The guide plate 37 includes a joint portion 37a joined to the rough lower surface 31x, a guide portion 37b that guides the path of the steel ball 60 to the second side surface 32c (second space S2 side), and a path of the steel ball 60 to the first. And a limiting portion 37c limited to the second side surface 32c side (second space S2 side). The length in the depth direction of the joint portion 37a, the guide portion 37b, and the limiting portion 37c is substantially the same as the length in the depth direction of the rough lower surface 31x.

  The joint portion 37a is a portion joined to a boundary region between the coarse lower surface 31x and the fine lower surface 31y. The joint 37a and the rough lower surface 31x are joined by, for example, welding. The guide portion 37b is a portion that extends from the steel ball chute side end portion of the joint portion 37a toward the second side surface 32c. For example, the guide portion 37b moves to the second side surface 32c up to a position where the horizontal position substantially coincides with the position of the horizontal end portion on the massive chute 35 side at the upper end of the exhaust pipe 32d connected to the second side surface 32c. It extends towards. The limiting portion 37c is a portion that extends vertically downward from the lower end of the guiding portion 37b. In other words, the limiting portion 37c extends vertically downward toward the upper end of the exhaust pipe 32d connected to the second side surface 32c. The limiting portion 37c is not connected to the upper end of the exhaust pipe 32d connected to the second side surface 32c, and forms an inflow portion 37x through which the steel ball 60 can pass (inflow) between the upper end of the exhaust pipe 32d. doing. In addition, from the viewpoint of ensuring the path of the rising airflow from the steel ball tank 33 side to the dust chute 34 by limiting the path of the steel ball 60, the inflow portion 37x is a space into which the steel ball 60 can flow. It may be made as small as possible.

  As shown in FIG. 4, by providing the guide plate 37, the second space S <b> 2 that is a path through which the steel ball 60 passes can be formed between the guiding portion 37 b and the limiting portion 37 c and the second side surface 32 c. . Further, since the path through which the steel ball 60 passes is limited by the guiding part 37b and the limiting part 37c, the path between the guiding part 37b and the limiting part 37c and the first side surface 32b is the first ascending airflow path. It can be a space S1. Ascending air current is guided in the direction of the opening 39 and the dust chute 34 by the guide plate 37, and the air flow from the third space S3 to the first space S1 does not change the velocity vector, so that the flow toward the second space S2 having a different direction is suppressed. Therefore, the dust 70 can be prevented from staying in the steel ball chute 32 because the dust inflow from the inflow portion 37x is not inhibited.

  In addition, although only the guide plate 37 was demonstrated as the airflow formation part 100 which forms airflow, about the 1st side surface 32b which divides 1st space S1 mentioned above with the guide plate 37, and the exhaust pipe 32d which divides 3rd space S3. Is also included in the airflow forming unit 100.

[Effect of this embodiment]
As described above, the steel ball recovery device 3 according to the present embodiment includes the shot cleaning steel balls 60 sprayed in the boiler 50 and the heat transfer tubes of the boiler 50 by spraying the steel balls 60. A sieve portion 31 for discharging dust 70 to be removed through a sieve, a steel ball chute 32 for feeding the steel ball 60 discharged from the sieve portion 31 downward, and a steel ball chute 32 for sending out the steel ball chute 32. Formed between the steel ball tank 33 for storing the steel ball 60, the dust chute 34 for sending the dust 70 discharged from the sieve portion 31 to the outside of the steel ball collecting device 3, the steel ball chute 32 and the dust chute 34. Further, an opening 39 for passing the dust 70 and an air flow toward the dust chute 34 from the path side of the steel ball 60 toward the steel ball tank 33 through the opening 39 are formed. It includes a stream forming unit 100, a.

  FIG. 5 is a longitudinal sectional view showing a steel ball collection device 203 according to a comparative example. As shown in FIG. 5, in the steel ball collection device 203, the dust 70 does not fall entirely from the fine sieve 31f to the dust chute 234, and some dust 70 enters the steel ball chute 232 from the coarse sieve 31h. There is a risk that. That is, when a large amount of dust 70 discharged from the boiler 50 is supplied to the steel ball collecting device 203 in a short period, a part of the dust 70 is transferred to the coarse sieve 31h which is the next sieve of the fine sieve 31f. Then, the steel ball chute 232 may enter from the coarse sieve 31h. In addition, particularly fine dust 70 may receive airflow and float above the sieve mesh, and then sink to the coarse sieve 31 h side and enter the steel ball chute 232. Further, the dust 70 attached so as to cover the steel ball 60 may enter the steel ball chute 232 from the coarse sieve 31 h together with the steel ball 60. The dust 70 that has entered the steel ball chute 232 in this way falls into the steel ball tank 33 provided below the steel ball chute 232 and stays in the steel ball tank 33. And as above-mentioned, the 2nd rotor 36b will flow a part of high pressure air from the steel ball conveyance blower 38 to the steel ball tank 33 side as leak air. The steel ball 60 having a high specific gravity reaches the steel ball cutting device 36 without being affected by the air flow based on the leak air, but the dust having a low specific gravity is prevented from descending to the steel ball cutting device 36 by the air flow. There is. As a result, dust 70 accumulates inside the steel ball tank 33, and as a result, the steel balls 60 are suspended in the steel ball tank 33, and the steel ball tank 33 may be blocked.

  In this regard, in the steel ball recovery device 3 according to the present embodiment, as shown in FIG. 2, an upward air flow is formed from the path side of the steel ball 60 toward the steel ball tank 33 through the opening 39 to the dust chute 34. Therefore, the dust 70 toward the steel ball tank 33 is easily guided in the direction of the dust chute 34 by the rising airflow. Thereby, it is possible to suppress the dust 70 discharged to the steel ball chute 32 without being properly separated from entering the steel ball tank 33. As described above, according to the steel ball recovery device 3 according to the present embodiment, accumulation of dust 70 inside the steel ball tank 33 can be suppressed, and blockage of the steel ball tank 33 can be suppressed.

  The airflow forming unit 100 includes a guide plate 37 that divides the internal space of the steel ball chute 32 into a first space S1 that guides the upward airflow to the opening 39 and a second space S2 that guides the steel ball 60 downward. . The steel ball 60 is directed from the steel ball chute 32 to the lower steel ball tank 33, and the upward air flow is directed from the steel ball tank 33 to the upper steel ball chute 32. The air flow path overlaps. In this case, the upward flow is weakened by the downward flow of the steel ball 60, and the flow rate of the upward flow may be reduced. In this regard, the guide plate 37 partitions the space into which the upward air current is guided to the opening 39 (first space S1) and the space where the steel ball 60 is guided downward (second space S2). It can suppress weakening.

  In the internal space of the steel ball chute 32, a third space S3 through which an updraft flows toward the first space S1 is formed, and the steel ball chute 32 has a steel ball 60 from the second space S2 to the third space S3. Has a second side surface 32c. Since the steel ball 60 is guided from the second space S2 to the third space S3 by the second side surface 32c, the steel ball 60 and the dust 70 that have moved downward in the second space S2 are converted into an ascending current in the third space S3. It will be exposed. Thereby, the dust 70 that has moved downward in the second space S2 can be appropriately guided in the direction of the opening 39 and the dust chute 34 by the rising airflow.

  The guide plate 37 is provided so that the first space S <b> 1 is positioned vertically above a connection portion between the steel ball chute 32 (more specifically, the inlet nozzle 32 e) and the steel ball tank 33. Accordingly, it is possible to appropriately guide the dust 70 in the direction of the dust chute 34 without changing the direction of the ascending air flow guided to the opening 39 in the first space S1.

  An air source 90 that supplies air is provided, and the guide plate 37 of the airflow forming unit 100 forms an ascending airflow that includes air supplied from the air source 90. By supplying air from the air source 90, a strong ascending current (a sufficient flow rate) can be formed by the guide plate 37.

  The air source 90 supplies cooling air into the steel ball tank 33.

  A first rotor 36a that cuts out a predetermined amount of the steel ball 60 stored in the steel ball tank 33; a second rotor 36b that discharges the steel ball 60 cut out by the first rotor 36a downstream of the first rotor 36a; And a casing 36c for housing the first rotor 36a and the second rotor 36b. The first rotor 36a has a plurality of pockets 36s1 that accommodate the steel balls 60 in the circumferential direction, and a gap cl1 that is greater than or equal to the maximum diameter Ot of the steel balls 60 is formed between the first rotor 36a and the casing 36c. The second rotor 36b has a plurality of pockets 36s2 that accommodate the steel balls 60 in the circumferential direction, and a gap cl2 that is equal to or smaller than the minimum diameter of the steel balls 60 is formed between the second rotor 36b and the casing 36c. The pocket 36s2 of the second rotor 36b has a larger volume than the pocket 36s1 of the first rotor 36a.

  By forming a gap cl1 that is greater than or equal to the maximum diameter Ot of the steel ball 60 between the first rotor 36a and the casing 36c, the steel ball 60 is caught between the first rotor 36a and the casing 36c. Can be prevented. In addition, since the clearance cl2 between the second rotor 36b and the casing 36c is set as a limit in manufacturing accuracy, it is possible to suppress excessive leakage air from the steel ball transfer blower 38. Further, since the volume of the pocket 36s2 of the second rotor 36b is made larger than the volume of the first rotor 36a, the steel ball 60 cut out from the first rotor 36a is not filled in the second rotor 36b. . Thereby, also in the 2nd rotor 36b by which the clearance gap cl2 was made small, it can suppress that biting of the steel ball 60 generate | occur | produces between the casings 36c.

[Modification]
The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, although it has been described that the steel balls 60 for shot cleaning are scattered in the boiler 50, the present invention is not limited to this, and any metal material or non-metal material may be used as the shot ball.

  Moreover, although the steel ball 60 and the dust 70 were demonstrated as classifying with the trommel sieve 31a, it is not limited to this, You may isolate | separate the steel ball 60 and the dust 70 with what is called a fixed sieve, a vibration sieve, and a resonance sieve.

  Further, the guide plate 37 has been described as extending from the boundary region between the steel ball chute 32 and the dust chute 34 toward the steel ball tank 33. However, the guide plate 37 is not limited to this. For example, the steel ball collecting device 103 shown in FIG. The guide plate 137 may be used. In the steel ball collecting device 103, the steel ball chute 132 and the dust chute 134 are communicated with each other via the connecting pipe 150. The guide plate 137 extends from the side surface of the steel ball chute 132 above the connecting pipe 150 toward the steel ball tank 33. Also in such a steel ball recovery device 103, the path of the steel ball 60 and the path of the ascending air current are partitioned by the guide plate 137, and the ascending air current is guided to the guide plate 137 through the connecting pipe 150. It will flow into the dust chute 134.

  Moreover, although it demonstrated that the dust 70 was induced | guided | derived to the dust chute 34 direction from the path | route side of the steel ball 60 with an updraft, the method of guiding the dust 70 to a dust chute is not limited to this. In the steel ball recovery device 153 shown in FIG. 7, the steel ball chute 182 and the steel ball tank 33 are connected via an exhaust pipe 182d extending vertically. The dust chute 184 is connected to the opening 189 on the side surface of the exhaust pipe 182d, whereby the steel ball chute 182 and the dust chute 184 communicate with each other. Further, the steel ball recovery device 153 includes an air source 190 that supplies air, and a pipe 191 that connects the air source 190 and the exhaust pipe 182d. The pipe 191 is connected to an opening on a side surface facing the side surface to which the dust chute 184 is connected in the exhaust pipe 182d. Further, the height of the pipe 191 and the height of the dust chute 184 substantially coincide with each other. The air supplied from the air source 190 passes through the pipe 191, passes through the exhaust pipe 182 d in the lateral direction, and flows into the dust chute 184 through the opening 189. In such a configuration, the air source 190 corresponds to the gas supply unit, and the pipe 191 and the exhaust pipe 182d correspond to the airflow forming unit.

  Moreover, like the steel ball collection | recovery apparatus 143 shown by FIG. 8, in addition to the structure demonstrated in embodiment, you may provide the exhaust pressure pipe 145 which connects the inside of the casing 36c and the inside of the dust chute 34. FIG. The exhaust pipe 145 directly connects the casing 36c and the dust chute 34 without using the steel ball tank 33 or the like. Specifically, one end of the exhaust pipe 145 is connected (connected) to the opening 36o on the side surface of the casing 36c, and the other end is connected to the opening 34o on the outer side surface 34c of the dust chute 34. More specifically, one end of the exhaust pipe 145 is a path from the first rotor 36a to the second rotor 36b on the side surface of the casing 36c (that is, downstream from the first rotor 36a and upstream from the second rotor 36b). Are connected to an opening 36o formed in the region (1).

  As described above, in the steel ball collection device 143 shown in FIG. 8, the inside of the casing 36 c and the inside of the dust chute 34 communicate with each other via the exhaust pressure pipe 145. For this reason, most of the leak air from the second rotor 36 b side flows from the casing 36 c into the exhaust pressure pipe 145 and is guided to the dust chute 34. As a result, leakage air flowing from the second rotor 36b side to the steel ball tank 33 can be reduced. Dust adhering to the steel ball 60 may flow into the steel ball tank 33 despite the dust separation at the inlet of the steel ball tank 33. When the dust 70 has entered the steel ball tank 33, the leak air from the second rotor 36 b flows into the steel ball tank 33 and is blown up inside the steel ball tank 33 due to the influence of the leak air. There is a possibility that the dust 70 accumulates and the steel ball tank 33 is blocked. In this regard, in the steel ball recovery device 143, at least a part of the leak air from the second rotor 36b side flows into the exhaust pressure pipe 145, so that the leak air flowing to the steel ball tank 33 side can be reduced. Thereby, blowing up of the dust 70 inside the steel ball tank 33 described above can be suppressed, and the dust 70 that has entered the steel ball tank 33 can be discharged to the outside of the steel ball collection device 143. That is, the blockage of the steel ball tank 33 described above can be further suppressed.

  As described above, the exhaust pressure pipe 145 is connected to the opening 36o formed in the path from the first rotor 36a to the second rotor 36b in the casing 36c. Upstream of the first rotor 36a, the steel balls 60 are full (see FIG. 3), and it is difficult to draw out leak air appropriately. On the other hand, downstream of the second rotor 36b, this is not an area where leakage air is reduced and is not appropriate. In this regard, by forming the opening 36o in the path from the first rotor 36a to the second rotor 36b and connecting the exhaust pressure pipe 145 to the opening 36o, the leak air can be appropriately extracted.

3, 103, 143, 153 ... Steel ball collecting device (shot ball collecting device), 31 ... Sieve part, 32, 132, 182 ... Steel ball chute, 32c ... Second side surface (guide wall), 33 ... Steel ball tank ( Shot ball tank), 34, 134, 184 ... dust chute, 36a ... first rotor, 36b ... second rotor, 36c ... casing, 36o ... opening, 36s1 ... pocket (first pocket), 36s2 ... pocket (second pocket) ), 37, 137 ... guide plates (partition plates), 38 ... steel ball transfer blowers (shot ball transfer blowers), 39 ... openings, 50 ... boilers, 60 ... steel balls (shot balls), 70 ... dust, 90,190 ... Air source (cooling gas supply part), 100 ... Airflow forming part, 145 ... Exhaust pressure pipe, 182d ... Exhaust pipe (airflow forming part), 191 ... Pipe (airflow forming part), cl1, cl2 ... Gap, 1 ... first space, S2 ... second space, S3 ... third space.

Claims (8)

Shot spheres for shot cleaning dispersed in the boiler, and sieve portions for discharging dust removed from the heat transfer tubes of the boiler by sieving the shot spheres, respectively,
A shot ball chute that sends the shot ball discharged from the sieve part downward;
Below the shot ball chute, a shot ball tank that stores the shot ball sent out by the shot ball chute,
A dust chute for sending the dust discharged from the sieve part to the outside;
An opening formed between the shot ball chute and the dust chute for allowing the dust to pass through;
An airflow forming unit that forms an airflow from the path side of the shot sphere toward the shot sphere tank to the dust chute through the opening ; and
The airflow forming unit includes a partition plate that partitions an internal space of the shot ball chute into a first space that guides the rising airflow to the opening and a second space that guides the shot ball downward. Cotto ball collection device. In the internal space of the shot ball chute, a third space is formed through which an air flow rising toward the first space passes.
The shot ball chute, said second space having a third guiding the shot ball in the space guide wall, shot ball collection apparatus according to claim 1. The shot ball collection device according to claim 2 , wherein the partition plate is provided such that the first space is positioned on a linear extension of the airflow passing through the third space. A gas supply unit for supplying gas;
The air flow forming unit forms the air flow containing the gas supplied from the gas supply unit, the shot ball collection device of any one of claims 1-3. The shot sphere recovery device according to claim 4 , wherein the gas supply unit includes a cooling gas supply unit that supplies a gas for cooling into the shot sphere tank. Shot spheres for shot cleaning dispersed in the boiler, and sieve portions for discharging dust removed from the heat transfer tubes of the boiler by sieving the shot spheres, respectively,
A shot ball chute that sends the shot ball discharged from the sieve part downward;
Below the shot ball chute, a shot ball tank that stores the shot ball sent out by the shot ball chute,
A dust chute for sending the dust discharged from the sieve part to the outside;
An opening formed between the shot ball chute and the dust chute for allowing the dust to pass through;
An air flow forming unit that forms an air flow from the path side of the shot sphere toward the shot sphere tank to the dust chute through the opening;
A first rotor for quantitatively cutting out the shot sphere stored in the shot sphere tank;
A second rotor that discharges the shot sphere cut out by the first rotor while suppressing leakage against pressure on the discharge port side downstream of the first rotor;
A casing for housing the first rotor and the second rotor;
A shot ball collecting device comprising: a pressure exhaust pipe for communicating the inside of the casing and the inside of the dust chute .   The shot ball collecting device according to claim 6, wherein the exhaust pipe is connected to a path from the first rotor to the second rotor in the casing. The first rotor has a plurality of first pockets arranged around a rotation center and capable of accommodating the shot balls,
The second rotor has a plurality of second pockets arranged around a rotation center and capable of accommodating the shot balls,
The gap between the first rotor and the casing is greater than the gap between the second rotor and the casing, the volume of the second pocket is greater than the volume of the first pocket, according to claim 6 or 7, wherein Shot ball collection device.

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