JP3147825U - Low water level drainage pump - Google Patents

Abstract

[PROBLEMS] A low water level drainage pump that drains muddy water generated at a tunnel excavation work site, etc. at a low water level, and can perform continuous drainage stably while releasing the air lock and maintaining the bottom water level. Provide low water level drainage pumps. A pump casing is fixed to a predetermined height inside a strainer that surrounds a lower portion of a housing of a drainage pump, and a water passage hole provided at the center of the pump casing. In a low water level drainage pump 1 in which a motor rotating shaft 5 is provided in a suspended state and an impeller 6 is fixed to the lower portion of the rotating shaft 4, an auxiliary impeller 7 is provided at a lower end portion of the rotating shaft 5 protruding below the impeller 6. The auxiliary impeller 7 is formed by being provided with a female screw member 8 that is screwed to the rotating shaft 5 and a scraping plate 9 that forms a gradient at the lower part of the female screw member 8. [Selection] Figure 2

Description

  The present invention relates to a low water level drainage pump that drains muddy water generated at a tunnel excavation site at a low level.

  Conventionally, the face that is the tip of tunnel excavation work is excavated with a downward slope called “push-in”, but if a large amount of spring water is generated at the excavation site, the excavation work must be carried out efficiently. Therefore, it is necessary to install a drainage pump and perform forced drainage.

  As shown in FIG. 6, the conventional drainage pump used for this purpose has a large number of small-diameter holes 3 a at a predetermined height on the outer periphery of the lower portion of the strainer 3, and a presser fitting fixed inside the strainer 3. 10, a rubber pump casing 4 is supported, and a motor rotating shaft 5 is provided in a suspended state at the center upper portion of a water passage hole 4 a provided in the center of the pump casing 4, and a lower end portion of the rotating shaft 5. The impeller 6 is attached to the male screw 5a and fastened with a nut 12.

  Further, when a drainage pump having the above structure is installed in spring water at a tunnel excavation site or the like and a motor (not shown) is driven, the impeller 6 rotates to start a pumping operation. At this time, the muddy water filtered through the small-diameter hole 3a of the strainer 3 contains small-diameter earth and sand. When this earth and sand passes upward through the water passage hole 4a and hits the blade part 6a of the impeller 6, the blade part Since 6a wears, it is set as the structure which provided sufficient clearance between the blade | wing part 6a and the pump casing 4. FIG.

  However, according to the above configuration, since the lower end position of the blade portion 6a of the impeller 6 becomes high and the water level does not reach the blade portion 6a of the impeller 6, water cannot be raised even if the impeller 6 is rotated. When the impeller 6 is rotated in this state, air is sucked up, and an air lock phenomenon occurs in which the air layer generated above stops the pumped water flow. For this reason, the water level rises and falls irregularly, and the drainage work cannot be continuously performed in a state where the low water level is maintained, so that the efficiency of the excavation work is significantly reduced.

By the way, as a prior art made | formed in order to avoid said air lock phenomenon, there exist some which are shown to patent document 1, for example. In this document, an impeller of a submersible pump is disclosed, and a configuration in which a wide blade plate wider than the blade plate is interposed between a plurality of blade plates provided in a shroud corresponding to an impeller. Even if there is an air layer above the upper edge of the pump discharge port start end, the wide blade plate is submerged, so that the air is discharged together with water by stirring the wide blade plate. Yes.
Japanese Patent Laid-Open No. 2001-248591

  By the way, in the structure of said patent document 1, since the wide blade board formed the several blade board of the shroud broadly, in the structure of this literature, it became necessary to manufacture a shroud newly, and existing It is impossible to adopt a simple improvement method that uses the structure of

  The present invention was made in view of the above circumstances, and is a low water level drainage pump that drains muddy water generated at tunnel excavation work sites, etc. at a low water level, and is simply improved by utilizing the existing impeller as it is. Accordingly, an object of the present invention is to provide a low water level drainage pump that can stably perform continuous drainage while releasing the air lock and maintaining the bottom water level.

  In order to solve the above problems, the low water level drainage pump according to claim 1 of the present invention is such that the pump casing is fixed at a predetermined height inside the strainer surrounding the lower part of the housing of the drainage pump, and the pump casing In the low water level drainage pump in which the motor rotating shaft is provided in a suspended state at the center of the water passage hole provided in the center of the shaft and the impeller is fixed to the lower portion of the rotating shaft, the lower end of the rotating shaft protruding below the impeller An auxiliary impeller is fastened to a portion, and the auxiliary impeller is provided with a female screw member screwed to a rotating shaft and a scraping plate that forms a gradient at a lower portion of the female screw member.

  A second aspect of the present invention according to the first aspect is characterized in that, in the first aspect, the auxiliary impeller is formed by alternately fixing two scraping plates to the end portion of the female screw member with a gradient.

  The low water level drainage pump of the present invention has a configuration in which an auxiliary impeller is fastened to the lower end portion of the rotating shaft protruding below the impeller while the existing impeller is attached to the rotating shaft provided in a suspended state on the low water level draining pump. Therefore, the existing impeller is used as it is, and the auxiliary impeller can be easily attached.

  Moreover, the auxiliary impeller fastened to the rotating shaft has a structure that is attached to a position below the existing impeller, that is, a position that is lower than the existing impeller. For this reason, since the auxiliary impeller that rotates along with the existing impeller by driving the motor rotates at a lower water level position than the existing impeller, the low impeller has a low water level due to the rotation of the lifting plate having a gradient provided in the auxiliary impeller. The water is scraped upward, and the air lock can be released by the water flow, and continuous drainage can be performed while keeping the low water level constant.

  Therefore, when the low water level drainage pump having the above configuration is used at a tunnel excavation work site or the like, for example, when it is installed at a spring water location of a face, mud containing small sediments filtered by a strainer is continuously at a low level. It is possible to drain water, and the spring water is kept at a certain low water level, which is also beneficial for improving the efficiency of excavation work.

  Embodiments of the present invention will be described below with reference to the drawings.

  The low water level drainage pump 1 according to the present invention is pumped to a predetermined height inside a strainer 3 (see FIG. 1) surrounding the lower part of the housing 2 of the drainage pump 1 as shown in FIGS. 2 (a) and 2 (b). The casing 4 is fixed, and the motor rotating shaft 5 is provided in a suspended state at the center of a water passage hole 4 a provided in the center of the pump casing 4, and the impeller 6 is fixed to the lower portion of the rotating shaft 5. In the low water level drainage pump 1, an auxiliary impeller 7 is fastened to the lower end portion of the rotating shaft 5 protruding below the impeller 6, and the auxiliary impeller 7 is screwed to the rotating shaft 5 with the female screw member 8 and the female screw. A scraping plate 9 that forms a gradient is provided at the lower part of the member 8.

  The low water level drainage pump 1 will be described in detail. As shown in FIG. 1, the strainer 3 has a bottomed circumferential shape so as to surround the lower part of the housing 2 of the drainage pump 1, and the circumferential side thereof. Are formed with a plurality of small-diameter holes 3a, 3a ... at a predetermined height, and small-diameter earth and sand passing through these small-diameter holes 3a, 3a ... flows into the strainer 3 together with muddy water.

  Further, as shown in FIGS. 2A and 2B, a rubber pump casing 4 is fixedly supported on the presser fitting 10 fixed inside the strainer 3, and provided at the center of the pump casing 4. A motor rotating shaft 5 is provided in a suspended state at the center of the passing hole 4a. A motor (not shown) is provided on the upper portion of the rotating shaft 5, and the impeller 6 is attached to the lower end portion of the rotating shaft 5 via a washer 11.

  In order to fasten the impeller 6 to the rotary shaft 5, in the conventional case, it is fastened with a nut 12 as shown in FIG. 6. In this embodiment, instead of the nut 12, a female screw 8 a of the auxiliary impeller 7 is used. The impeller 6 is fastened by screwing it to the male screw 5a at the lower end of the rotating shaft 5. However, although not shown, if the impeller 6 is fastened with the normal nut 12 shown in FIG. 6 and there is a surplus length exposed on the male screw 5a of the rotating shaft 5 below the nut 12, this exposed male The female screw 8a of the auxiliary impeller 7 may be fastened to the screw 5a.

  In any case, when the auxiliary impeller 7 is fastened to the male screw 5a of the rotary shaft 5, as shown in FIG. 3, the auxiliary impeller is provided at the lower center of the existing impeller 6 having blade plates 6a, 6a,. 7 is provided, and as shown in FIG. 2B, the auxiliary impeller 7 has a positional relationship in which it is suspended below the existing impeller 6.

  Further, as described above, the auxiliary impeller 7 of the present embodiment can be easily attached using the existing rotating shaft 5 and also serves as a nut for fastening the existing impeller 6.

  When the structure of the auxiliary impeller 7 is illustrated as a single unit, as shown in FIG. 4, a female screw member 8 that is screwed onto a male screw 5 a (see FIG. 2A) of the rotating shaft 5 and the female screw member 8. A scraping plate 9 having a gradient is provided at the bottom. As a specific structure of the auxiliary impeller 7, as shown in FIGS. 5A to 5D, two auxiliary impellers 7 are provided at the end of the mounting portion 8b of the female screw member 8 formed with a female screw 8a therein. It is set as the structure formed by making the gradient board 9 and 9 into a gradient alternately, and welding. As a result of various trials, it has been found that those having an angle of 55 ° with respect to the vertical line are excellent in terms of the efficiency of water scraping.

  When the low water level drainage pump 1 having the above structure is installed in spring water at a tunnel excavation site or the like and a motor (not shown) is driven, the impeller 6 rotates to start the pumping operation. At this time, as shown in FIG. 2B, the auxiliary impeller 7 fastened to the rotating shaft 5 is attached at a lower water level than the existing impeller 6, and the lower end of the auxiliary impeller 7 is the bottom surface of the strainer 3. It will be in the state where it hung down to the position close to.

  Accordingly, the low-level water is scraped upward by the rotation of the lifting plate 9 having a gradient, and the air lock can be released by the water flow, and at the low-water level where the lifting plate 9 of the auxiliary impeller 7 comes into contact. Continuous drainage can be performed. As a result, the spring water generated at the tunnel excavation work site and the like is maintained at a certain low water level, which is also useful for improving the efficiency of excavation work.

  The low-water level drainage pump of the present invention is a low-level drainage pump that drains mud generated at tunnel excavation work sites, etc. at low water levels. It can be used as a low water level drainage pump that can release and stably drain continuously with the bottom water level maintained.

1 is an overall perspective view of a low water level drainage pump according to the present invention. It is sectional drawing which shows the structure of the impeller periphery of the low water level drainage pump by this invention, (a) shows the condition before fastening an auxiliary impeller, (b) is sectional drawing which shows the state which fastened the auxiliary impeller. . It is a perspective view which shows the impeller and auxiliary impeller which were used for the low water level drainage pump by this invention. It is a perspective view of the auxiliary impeller attached to the low water level drainage pump by this invention. It is a figure which shows the auxiliary impeller of the low water level drainage pump by this invention, (a) is a front view, (b) is a top view of (a), (c) is a side view of (a), (d) is ( It is a bottom view of a). It is sectional drawing which shows the structure of the impeller periphery of the conventional low water level drainage pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Low water level drainage pump 2 Housing 3 Strainer 3a Small diameter hole 4 Pump casing 4a Water passage hole 5 Motor rotating shaft 5a Male screw 6 Impeller 6a Blade plate 7 Auxiliary impeller 8 Female screw member 8a Female screw 8b Mounting part 9 Lifting plate 10 Presser Metal fitting 11 Washer 12 Nut

Claims (2)

The pump casing is fixed at a predetermined height inside the strainer that surrounds the lower part of the drainage pump housing, and the motor rotating shaft is provided in a suspended state at the center of the water passage hole provided in the center of the pump casing. In a low water level drainage pump in which an impeller is fixed to the lower part of the rotating shaft,
An auxiliary impeller is fastened to the lower end portion of the rotating shaft that projects downward from the impeller. The auxiliary impeller is provided with a female screw member that is screwed to the rotating shaft and a scraping plate that forms a gradient at the lower portion of the female screw member. A low water level drainage pump characterized by 2. The low water level drainage pump according to claim 1, wherein the auxiliary impeller is formed by alternately fixing two scraping plates at an end portion of the female screw member with a gradient.