JP6695744B2 - Screw pump and manufacturing method thereof - Google Patents

Description

  The present invention relates to a shaft split type screw pump and a manufacturing method thereof.

  As this type of technology, there is one described in Patent Document 1 below. The conventional technique is configured as follows. The joint flanges are welded and fixed to the ends of the two divided screws by adjusting the parallelism and the axis of the two screws. The joint flange is welded and fixed to the inner surface of each split screw shaft.

  By dividing the screw into two dividing screws, the screw can be divided and transported, which facilitates transportation of the screw from the factory to the site or from the field to the factory. Further, since the upstream side of the screw is a part that is repeatedly submerged in water or exposed to the atmosphere, the screw blade on the upstream side is more likely to corrode than the screw blade on the downstream side. If the screw is divided into two divided screws, it is easy to take partial anticorrosion measures only on the upstream screw blade where corrosion is likely to proceed.

JP, 2005-40529, A

  The above-mentioned conventional technique has the following problems. In order to match the shaft centers of the two split screws, it is necessary to make a right angle to the joint surface of the joint flange with respect to the shaft core of the split screw shafts, and to adjust the shaft core of the split screw shaft and the joint flange. There is.

  Here, the total length of the screw shaft is determined by the pump head, the inclination angle, etc., and is, for example, about 6 m to 12 m. Therefore, the length of each of the dividing screws is, for example, about 3 m to 6 m. It is not easy to accurately fix the joining flange to the ends of the split screws having such length dimensions so that the axes of the two split screws are aligned.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a shaft split type screw pump having a structure that facilitates adjustment of the axial center of a screw shaft, and a manufacturing method thereof.

  The present invention includes a tubular first screw shaft having an outer peripheral surface to which a screw blade is attached, and a tubular second screw shaft having an outer peripheral surface to which the screw blade is attached and connected to the first screw shaft. It is a shaft split type screw pump provided. The first screw shaft and the second screw shaft are in a form in which the facing surfaces are connected to each other via a pair of concave and convex flanges, and the concave side flange of the pair of flanges is the The convex side flange is attached to the inner surface of the axial end portion of the first screw shaft, and the convex side flange is attached to the inner surface of the axial end portion of the second screw shaft. The first screw shaft has a first short pipe portion to which the concave side flange is attached on the inner surface of the end portion in the axial direction, and the length of the first short pipe portion is 1000 mm or less. And

  In the method for manufacturing a screw pump according to the present invention, the concave side flange, which has not been concaved, is attached to the inner surface of the axial end of the first short pipe section, and then the concave side flange is machined. A flange mounting that is formed by machining, and after mounting the convex side flange with no convex portion machined on the inner surface of the axial end portion of the second screw shaft, forms the convex portion on the convex side flange by machining. A step, a screw shaft forming step of forming a screw shaft by connecting the first screw shaft to which the concave side flange is attached and the second screw shaft to which the convex side flange is attached, and the first screw And a blade attaching step of welding and fixing a screw blade to each of the outer peripheral surface of the shaft and the second screw shaft.

  A short pipe (first short pipe portion) having a length of 1000 mm or less is easy to mount on a milling machine, for example. By mounting the short pipe on the milling machine, it is easy to machine the concave flange attached to the inner surface of the axial end of the short pipe (first short pipe portion). That is, according to the present invention, it is easy to adjust the axis of the screw shaft.

It is a side view of the screw pump which concerns on one Embodiment of this invention. It is the A section enlarged view of FIG. It is a figure which shows the manufacturing procedure of the flanged short pipe which has a convex side flange. It is a figure which shows the manufacturing procedure of a screw main body. It is a figure which shows the manufacturing procedure of a screw main body. It is a figure which shows the manufacturing procedure of a screw main body. It is a figure which shows the manufacturing procedure of a screw main body.

  Embodiments for carrying out the present invention will be described below with reference to the drawings. The screw pump of the present invention is an open type pump that pumps water with a rotating screw, and is used as a pump for a rainwater pump station, a pump facility in a sewage treatment plant, or the like.

  Further, the screw pump of the present invention is a shaft split type screw pump. The screw pump of the present invention can be applied to a new screw pump, or the screw pump of the present invention can be applied to an existing screw pump by replacing only the corroded screw portion of the existing screw pump.

(Structure of screw pump)
As shown in FIG. 1, the screw pump 100 includes a screw body 1 installed in a trough 50 that is inclined with respect to the horizontal direction, and an upper bearing 4 and a lower bearing 2 that support the screw body 1. There is. An upper spindle 3 is attached to the upper end of the screw body 1, and the screw body 1 is supported by being suspended by an upper bearing 4 via the upper spindle 3. A drive device (not shown) such as an engine or an electric motor that rotates the screw body 1 transmits the rotational driving force to the screw body 1 via the gear coupling 5.

  The screw body 1 is a split type screw body composed of a lower (upstream) first screw 6 and an upper (downstream) second screw 7.

  The first screw 6 has a cylindrical first screw shaft 8 to which a first screw blade 9 is attached on the outer peripheral surface, a conical barrel 10 is attached to one (lower) end, and the end thereof is attached. The lower end plate 11 is attached. On the other end, the concave side flange 12 of the pair of flanges 12 and 15 having the concavo-convex surfaces (waxes) is attached.

  The second screw 7 has a cylindrical second screw shaft 13 to which the second screw blade 14 is attached on the outer peripheral surface, and has a convex portion corresponding to the concave flange 12 described above at one (lower) end portion. The side flange 15 is attached, and the upper end plate 16 is attached to the other end.

  The screw shafts 8 and 13 are made of STPY (arc welded steel pipe), for example, and the screw blades 9 and 14 are made of SS, for example. The material of the screw shafts 8 and 13 and the screw blades is not limited to this. It is also preferable that the first screw blade 9 installed in the lower portion of the trough 50 that easily corrodes is made of stainless steel (for example, SUS304) as a countermeasure against corrosion. Further, it is also preferable to apply the FRP lining to the SS first screw blade 9. In this case, it is also preferable to improve the adhesion of the FRP lining by subjecting the edges of the blades to R processing of a predetermined dimension. It is not always necessary that all of the first screw blades 9 are made of stainless steel, or that all of the first screw blades 9 are FRP-lined, and the lower end portion (upstream side end) that is repeatedly submerged or exposed to the atmosphere The above-mentioned measures may be taken only for the part). Further, instead of the FRP lining, corrosion-resistant coating or other anticorrosion treatment may be applied to all of the first screw blades 9 or the lower end portion (upstream end portion).

<Structure of screw shaft connecting part>
FIG. 2 is an enlarged view of part A in FIG. The concave flange 12 is attached to the inner surface of the axial end of the first screw shaft 8, and the convex flange 15 is attached to the inner surface of the axial end of the second screw shaft 13.

  The concave side flange 12 is a ring-shaped flange in which a concave portion 12c is formed. The convex side flange 15 is a ring-shaped flange in which the convex portion 15c is formed.

  The concave side flange 12 and the convex side flange 15 are coupled and fixed by a plurality of coupling bolts 17 and nuts 18 in a state where the convex portion 15c is fitted in the concave portion 12c. As shown in the plan view of the convex side flange 15 in FIG. 3, the convex side flange 15 is provided with a large number of (a plurality of) bolt holes 22 into which the connecting bolts 17 are inserted, and in the circumferential direction. Two pin holes 23 into which parallel pins (not shown) as positioning members (phase determining members) are respectively inserted are provided. Although not shown, the concave side flange 12 is also provided with a large number of (a plurality of) bolt holes 22 and two pin holes 23, like the convex side flange 15. As shown in FIG. 2, an annular groove into which a ring-shaped gasket 19 (seal) is fitted is formed on the surface of the concave side flange 12 facing the convex side flange 15.

(Screw body manufacturing procedure)
A procedure for manufacturing the screw body 1 will be described with reference to FIGS. 2 to 7.

  The total length of the screw shaft formed by connecting the first screw shaft 8 and the second screw shaft 13 is determined by the pump head, the tilt angle, and the like, and is, for example, about 6 m to 12 m. The shaft diameter is, for example, about 0.6 m to 1.8 m. As shown in FIG. 4, the first screw shaft 8 is formed by welding together pipes 8a, 8b, 8c (cylindrical members) formed by bending and welding steel plates. The second screw shaft 13 is formed by welding together pipes 13a, 13b, 13c, 13d, 13e (cylindrical members) formed by bending and welding steel plates.

  Here, in the screw shaft of the present embodiment, the pipe 8a forming the first screw shaft 8 and the pipe 13a forming the second screw shaft 13 among the plurality of pipes connected to each other in the axial direction are Are also short tubes 8a and 13a having a length of 800 mm, for example. The length of the short tubes 8a and 13a is preferably 1000 mm or less, and the lower limit of the length is about 200 mm.

  The flange mounting process will be described with reference to FIGS. Note that this step is the same for the short pipe 13a forming the second screw shaft 13 and the short pipe 8a forming the first screw shaft 8, so that the short pipe 13a forming the second screw shaft 13 is represented. And shown in FIG. The short pipe 8a is a first short pipe portion that forms the first screw shaft 8, and the short pipe 13a is a second short pipe portion that forms the second screw shaft 13. The "first" of the first short pipe part means that the short pipe part of the "first" screw shaft, and the "second" of the second short pipe part means the short pipe of the "second" screw shaft. Means a part.

<Flange mounting process>
First, the inner surface of the axial end of the short tube 13a is machined to form the annular step portion 24. Then, the convex side flange 15 which is not processed (the convex portion 15c is not formed yet) is inserted into the step portion 24 and welded, so that the convex side flange 15 is attached to the short pipe 13a. At this time, the convex side flange 15 is inserted into the step portion 24 of the short tube 13a from above the short tube 13a laid sideways (the axial direction of the short tube 13a is the vertical direction). After placing the convex side flange 15 and performing fine adjustment so that the axial center of the short pipe 13a and the axial center of the convex side flange 15 coincide with each other, the convex side flange 15 is welded and fixed to the short pipe 13a.

  As described above, since the short pipe 13a is a pipe formed by bending and welding a steel plate, its inner surface may not be a perfect circle (low roundness). Therefore, the inner surface of the axial end of the short pipe 13a is machined to form the annular step portion 24. Accordingly, when the convex side flange 15 is inserted into the short pipe 13a, the convex side flange 15 is forcibly pushed into the short pipe 13a, so that the short pipe 13a may be damaged or the short pipe 13a may be deformed. It is possible to prevent the short pipe 13a from being hooked. There is also an advantage that the convex side flange 15 can be temporarily received by the step portion 24.

  Next, the convex side flange 15 is formed with a convex portion 15c (not limited to a perfect circle, an elliptical shape or a polygonal shape may be used, and the concave portion 12c of the concave side flange 12 is also formed) by machining using a milling machine or the like. The axial end surface 25 of the peripheral edge portion of the flange 15 and the axial end surface e of the short tube 13a (second screw shaft 13) are integrally (simultaneously machined) flush with each other. Thereby, the flanged short pipe 20 is formed in which the convex side flange 15 is attached to the inner surface of the end portion of the short pipe 13a. The flanged short pipe 21 (see FIG. 4) in which the concave flange 12 is attached to the inner surface (step portion 26) of the end of the short pipe 8a by the same (similar) method as the method of forming the short pipe 20 with a flange. Is formed.

  The step portion 24 described above is a second step portion formed on the inner surface of the axial end portion of the second screw shaft 13, and the step portion 26 shown in FIG. 2 is the axial direction of the first screw shaft 8. Is a first step formed on the inner surface of the end of the. The "first" of the first step means that it is the step of the "first" screw shaft, and the "second" of the second step is that of the "second" screw shaft. Means

<Screw shaft forming process>
First, the flanged short pipe 21 (concave side flange 12 to which the short pipe 8a is attached) and the flanged short pipe 20 (convex side flange 15 to which the short pipe 13a is attached) are stamped together. Fitting with (concave portion 12c, convex portion 15c) and connecting with connecting bolt 17 and nut 18, a parallel pin is inserted into pin hole 23. Subsequently, the pipes 8b and 8c are connected to the short pipe 8a (short pipe with flange 21) by welding in this order, and the pipes 13b, 13c, 13d, and 13e are arranged in this order in the short pipe 13a (short pipe with flange 20). ) By welding. As a result, a screw shaft composed of the first screw shaft 8 and the second screw shaft 13 is formed.

<Blade mounting process>
Next, as shown in FIG. 5, the first screw blade 9 formed by bending the steel plate is welded and fixed to the outer peripheral surface of the first screw shaft 8 to form the second screw blade 14 formed by bending the steel plate. The outer peripheral surface of the second screw shaft 13 is fixed by welding. At this time, the screw shaft is placed on the gantry 40 in which the roller 40a is arranged at the upper end, and the screw blades are attached by welding while rotating the screw shaft at appropriate times. The boundary portion 30 between the first screw blade 9 that is welded and fixed to the first screw shaft 8 and the second screw blade 14 that is welded and fixed to the second screw shaft 13 includes the first screw blade 9 and the second screw blade 14. After making fine adjustments so that the lines continue smoothly, this part is temporarily fixed by spot welding. The temporary fixing method is not limited to spot welding.

<Upper and lower end plate installation process>
Thereafter, as shown in FIG. 6, the conical barrel 10 is attached to the end of the first screw shaft 8 and the lower end plate 11 is attached to the end of the conical barrel 10. Further, the upper end plate 16 is attached to the end of the second screw shaft 13. As a result, the screw body 1 is formed.

<Blade tip cutting process>
After that, as shown in FIG. 7, the mount supporting the screw body 1 is changed from the mount 40 to the mount 41. The screw main body 1 is supported so that both ends of the screw main body 1 are sandwiched by the rotating jig 41a of the gantry 41. A recess (not shown) is provided at the center of the upper and lower end plates 16 and 11, and the tapered tip of the rotary jig 41a is applied to this recess. The belt 42 is hung on the outer peripheral surface of the screw shaft (second screw shaft 13) and the belt 42 is rotated by the belt drive device 43, whereby the screw body 1 is rotated around its axis.

  Further, a rail 45 supported by a plurality of legs 44 is arranged parallel to the screw body 1 on the side of the screw body 1, and a cutting machine 46 (for example, a plasma torch) runs on the rail 45. It is supposed to do.

  The cutting machine 46 is run while rotating the screw body 1 (screw shaft) around its axis, and the tip end portions of the screw blades 9 and 14 are cut and processed by the cutting machine 46, and the outer diameters of the screw blades 9 and 14 are cut. Make the dimensions the same as the outer dimensions. After the blade tip processing, the lower end plate 11 and the upper end plate 16 are machined. By machining both ends of the screw in an integrated state, it becomes easy to reproduce the shaft core in the field assembly after the division.

<Painting process, division process>
Then, the screw body 1 is painted. At the time of transportation to the site, the spot welding portion for temporarily fixing the first screw blade 9 and the second screw blade 14 is cut, and the connecting bolt 17 and the parallel pin are removed to remove the first screw 6 and the second screw. The screw body 1 is divided into the screw 7 and the screw 7.

(Modification)
The parallel pin inserted into the pin hole 23 of the convex side flange 15 (see FIG. 3, the same applies to the corresponding concave side flange 12) is such that the first screw blade 9 and the second screw blade 14 are smoothly continuous. This is a member for performing phase alignment in the rotational direction of the first screw 6 and the second screw 7. Instead of the parallel pin, a key, a reamer bolt, a phase determining piece (block), or the like may be used as a member for performing phase alignment in the rotation direction.

  The screw body 1 of the above-described embodiment is a two-division type screw body composed of the first screw 6 and the second screw 7, but may be a screw body divided into three or more.

  In the embodiment described above, the concave side flange 12 is attached to the end surface of the upstream screw shaft 8 and the convex side flange 15 is attached to the end surface of the downstream screw shaft 13, but, conversely, the upstream side The convex flange 15 may be attached to the end surface of the screw shaft 8, and the concave flange 12 may be attached to the end surface of the screw shaft 13 on the downstream side.

  In the above-described embodiment, both the first screw shaft 8 and the second screw shaft 13 have short pipes (8a, 13a) (short pipe portion of 1000 mm or less), but the first screw shaft 8 and the second screw Only one of the shafts 13 may have a short pipe (short pipe portion).

  In the embodiment described above, the annular steps 26 and 24 are provided on the inner surfaces of the axial end portions of the short pipe 8a (first screw shaft 8) and the short pipe 13a (second screw shaft 13), respectively. The steps 26 and 24 may be omitted. When the roundness of the short pipes (8a, 13a) (screw shafts 8, 13) is high, the short pipes (8a, 13a) (screw shafts 8, 13) cannot be processed without the step portions 26, 24. It is possible to insert the flanges (12, 15) into the short tubes (8a, 13a) (screw shafts 8, 13) without applying any force.

  In the above-described embodiment, the axial end surface 25 of the peripheral edge portion of the convex flange 15 and the axial end surface e of the short tube 13a (second screw shaft 13) are flush with each other (the concave flange 12 and the short flange 12). The same applies to the pipe 8a (first screw shaft 8)). Instead of this, the axial end surface 25 of the peripheral edge portion of the convex side flange 15 may project from the axial end surface e of the short pipe 13a (second screw shaft 13). Furthermore, the axial end surface 25 of the peripheral edge portion of the convex side flange 15 may be at a position recessed from the axial end surface e of the short tube 13a (second screw shaft 13) (the concave side flange 12 and The same applies to the short tube 8a (first screw shaft 8)).

(Action / effect)
The first screw shaft 8 has a short pipe 8a (first short pipe portion) having a length of 1000 mm or less, to which the concave flange 12 is attached on the inner surface of the axial end portion. Here, a short tube having a length of 1000 mm or less is easy to mount on a milling machine. By mounting the short tube 8a to which the concave side flange 12 is attached on the milling machine, the concave side flange 12 can be easily machined while adjusting the axial center of the screw shaft and the concave side flange 12 to be aligned with each other. be able to. That is, according to the present invention, it is easy to adjust the axis of the screw shaft.

  In the screw pump of the present invention, as in the above-described embodiment, the axial end surface of the concave side flange 12 of the peripheral edge portion facing the convex side flange 15 and the axial end surface of the first screw shaft 8 are: The end face 25 in the axial direction of the peripheral edge portion of the convex side flange 15 facing the concave side flange 12 and the end face e in the axial direction of the second screw shaft 13 are flush with each other. Preferably. According to this configuration, no depression or the like is formed in the connecting portion between the first screw shaft 8 and the second screw shaft 13. In other words, the outer peripheral surface of the connecting portion is a continuous surface. This can prevent dust and the like from sticking to the connecting portion. This provides corrosion protection for the connection.

  Further, as in the above-described embodiment, it is preferable that an annular step portion (26, 24) is formed on the inner surface of the axial end portion of the screw shaft, and the flange is attached to this step portion. With this configuration, when the flange is inserted into the screw shaft, it is possible to prevent the screw shaft from being forcibly pushed and being damaged or deformed. There is also an advantage that the flange can be temporarily received by the stepped portion.

  Regarding the production of the screw main body 1, in the present invention, a recessed (or convex) unprocessed flange is attached to the inner surface of the axial end of the screw shaft, and then the recessed (or convex) is formed on the flange by machining. Yes (flange mounting process). According to this procedure, the flanges 12 and 15 are attached to the screw shaft by welding or the like, and then the unevenness (marked wax) is processed. Therefore, when the flanges 12 and 15 are attached to the screw shaft, a mounting error (in the case of welding, The error due to welding distortion or the like can be canceled by the subsequent concave (or convex) machining. That is, it is easy to adjust the axis of the screw shaft.

  Regarding the production of the screw body 1, as in the above-described embodiment, the concave flange 12 (flange short tube 21) to which the first short tube portion 8a is attached and the convex side to which the second short tube portion 13a is attached. After connecting with the flange 15 (short pipe with flange 20), the first short pipe portion 8a and the second short pipe portion 13a are provided with pipes 8b and 8c (cylindrical members) and pipes 13b, 13c, 13d and 13e ( It is preferable to form the screw shaft by attaching a (cylindrical member). According to this configuration, since the screw shaft is formed so as to extend on both sides of the shaft core of the flanged short pipe 20, 21 with the shaft core aligned, the shaft core accuracy of the entire screw shaft is improved. It is easy to raise.

  Further, regarding the manufacture of the screw main body 1, as in the above-described embodiment, in the flange attaching step, after the concave side flange 12 having no concave portion is attached to the inner surface of the axial end portion of the first screw shaft 8, The axial end face of the peripheral edge of the side flange 12 facing the convex flange 15 and the axial end face of the first screw shaft 8 are machined to be flush with each other, and the second screw shaft is also machined. After attaching the convex side flange 15 with the convex portion unmachined to the inner surface of the axial end portion of 13, the axial end surface of the peripheral edge portion of the convex side flange 15 facing the concave side flange 12 and the second screw It is preferable to perform machining so that the axial end surface of the shaft 13 is integrally flush. According to this structure, the axial end faces of the peripheral portions of the flanges 12 and 15 and the axial end faces of the screw shafts 8 and 13 are precisely aligned while adjusting the axial centers of the screw shafts to match. Can be

  Regarding the production of the screw body 1, as in the above-described embodiment, the first screw blade 9 welded and fixed to the first screw shaft 8 and the second screw blade 14 welded and fixed to the second screw shaft 13 are provided. It is preferable that the screw blades 9 and 14 are temporarily fixed by spot welding and then the tip ends of the screw blades 9 and 14 are cut to make the outer diameter dimensions of the screw blades 9 and 14 to be a predetermined dimension and to make the outer diameter dimensions uniform. With this configuration, the continuity between the first screw blade 9 and the second screw blade 14 can be enhanced.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be implemented as long as they are set forth in the claims. ..

1: screw body 2: lower bearing 3: upper spindle 4: upper bearing 5: gear coupling 6: first screw 7: second screw 8: first screw shaft 8a: short pipe (first short pipe portion)
9: First screw blade 10: Conical barrel 11: Lower end plate 12: Concave side flange 12c: Recess 13: Second screw shaft 13a: Short pipe (second short pipe portion)
14: 2nd screw blade 15: convex side flange 15c: convex part 16: upper end plate 24: 2nd step part 26: 1st step part 100: screw pump

Claims (5)

A cylindrical first screw shaft having a plurality of divided cylindrical members connected to each other and having screw blades attached to the outer peripheral surface thereof ;
A screw blade is attached to the outer peripheral surface, and a cylindrical second screw shaft formed by joining a plurality of divided cylindrical members, which is connected to the first screw shaft,
The first screw shaft and the second screw shaft are in a form in which the facing surfaces are connected to each other via a pair of uneven flanges,
The concave side flange of the one set of flanges is attached to the inner surface of the axial end portion of the first screw shaft, and the convex side flange is attached to the inner surface of the axial end portion of the second screw shaft. ,
The first screw shaft has a first short pipe portion to which the concave flange is attached on an inner surface of an end portion in the axial direction, which is one of a plurality of divided cylindrical members, and A method for manufacturing a shaft split type screw pump having a length of 1000 mm or less,
After attaching the concave side flange having no concave portion to the inner surface of the axial end of the first short pipe section, a concave section is formed in the concave side flange by machining, and the shaft of the second screw shaft is formed. On the inner surface of the end in the direction, after mounting the convex side flange unprocessed convex portion, a flange mounting step of forming a convex portion on the convex side flange by machining,
A screw shaft forming step of forming a screw shaft by connecting the first screw shaft to which the concave side flange is attached and the second screw shaft to which the convex side flange is attached,
A blade attaching step of welding and fixing a screw blade to each of the outer peripheral surfaces of the first screw shaft and the second screw shaft,
A method for manufacturing a screw pump, comprising: A cylindrical first screw shaft having a plurality of divided cylindrical members connected to each other and having screw blades attached to the outer peripheral surface thereof ;
A screw blade is attached to the outer peripheral surface, and a cylindrical second screw shaft formed by joining a plurality of divided cylindrical members, which is connected to the first screw shaft,
The first screw shaft and the second screw shaft are in a form in which the facing surfaces are connected to each other via a pair of uneven flanges,
The concave side flange of the one set of flanges is attached to the inner surface of the axial end portion of the first screw shaft, and the convex side flange is attached to the inner surface of the axial end portion of the second screw shaft. ,
The second screw shaft has a second short pipe portion to which the convex side flange is attached on an inner surface of an end portion in the axial direction which is one of a plurality of divided cylindrical members . A method for manufacturing a shaft split type screw pump having a length of 1000 mm or less,
After mounting the concave side flange having no concave portion formed on the inner surface of the axial end portion of the first screw shaft, the concave side flange is formed by machining and the shaft of the second short pipe portion is formed. On the inner surface of the end in the direction, after mounting the convex side unprocessed convex side flange, a flange mounting step of forming a convex part on the convex side flange by machining,
A screw shaft forming step of forming a screw shaft by connecting the first screw shaft to which the concave side flange is attached and the second screw shaft to which the convex side flange is attached,
A blade attaching step of welding and fixing a screw blade to each of the outer peripheral surfaces of the first screw shaft and the second screw shaft,
A method for manufacturing a screw pump, comprising: The method for manufacturing a screw pump according to claim 1 ,
The second screw shaft has a second short pipe portion to which the convex side flange is attached on an inner surface of an end portion in the axial direction which is one of a plurality of divided cylindrical members . The length is 1000 mm or less,
In the flange mounting step, after mounting the concave side flange having no concave portion formed on the inner surface of the axial end of the first short pipe section, a concave section is formed in the concave side flange by machining, and A step of forming a convex portion on the convex side flange by machining after attaching the convex side flange with the convex portion unprocessed to the inner surface of the axial end of the second short pipe portion,
In the screw shaft forming step, after connecting the concave side flange to which the first short pipe section is attached and the convex side flange to which the second short pipe section is attached, the first short pipe section and the A method of manufacturing a screw pump, comprising a step of forming a screw shaft by attaching a cylindrical member to each of the second short pipe portions. In the method for manufacturing the screw pump according to any one of claims 1 to 3 ,
In the flange mounting step, after mounting the concave side flange of the concave portion unmachined on the inner surface of the axial end portion of the first screw shaft, of the peripheral side portion of the concave side flange facing the convex side flange. The end face in the axial direction and the end face in the axial direction of the first screw shaft are machined so as to be integrally flush with each other, and the inner surface of the end face in the axial direction of the second screw shaft has no protrusions. After mounting the convex side flange of the, the axial end surface of the convex side flange of the peripheral edge portion facing the concave side flange and the axial end surface of the second screw shaft are integrally flush with each other. A method of manufacturing a screw pump, which comprises performing a machining process that includes: In the manufacturing method of the screw pump according to any one of claims 1 to 4 ,
In order to make the outer diameter of the screw blade fixed to the outer peripheral surfaces of the first screw shaft and the second screw shaft by welding, the tip of the screw blade is rotated while rotating the screw shaft around its axis. Further equipped with a blade tip cutting step for cutting
In the blade attaching step, a screw blade welded and fixed to the first screw shaft and a screw blade welded and fixed to the second screw shaft are temporarily fixed, and a manufacturing method of a screw pump. ..

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