JP2015040529A - Screw pump and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw pump capable of securing continuity of a screw blade and reproducibility of rotation balance and the like by precisely reproducing a relative position around a rotation shaft core between split parts connected to each other, and a manufacturing method thereof.SOLUTION: The screw pump is provided with a screw in which screw blades are spirally arranged on an outer periphery of a screw shaft. The screw is split into plural split screws 511, 512 in a rotation shaft core direction, and each split screw 511, 512 has a split screw shaft 521, 522, and a split screw blade 531, 532. The screw pump has a circumferential direction positioning part 560 for positioning a relative position around rotation shaft cores of the split screws 511, 512, and a coupling and fixing part 570 for connecting ends of the split screws 511, 512 between ends opposed to each other between the split screws 511, 512 connected to each other.

Description

  The present invention relates to a screw pump and a manufacturing method, and more particularly to a technique for separately manufacturing a screw.

  Conventionally, as shown in FIGS. 9 and 10, this type of screw pump includes a screw 1, an upper bearing portion 4 and a lower bearing portion 5 that receive the rotating shafts 2 and 3 of the screw 1, and the screw 1 around the axis. A driving device 6 for rotational driving is provided.

  The screw 1 has screw blades 8 spirally arranged on the outer peripheral surface of a screw pipe 7, and its lower half in the radial direction is accommodated in a trough 9, and the trough 9 has an ascending slope made of a civil engineering structure. An inclined channel. This screw pump pumps water by rotating the screw 1 inside the trough 9.

  As a prior art of a screw pump, there exists a thing described in patent document 1, for example. This screw pump is used by connecting and integrating a plurality of divided screws, and each divided screw is provided with a screw blade on a screw tube shaft. One split screw has a connecting member and an engaging groove having an inner peripheral bearing surface at the connection side shaft end of the screw tube shaft, and the other split screw has an outer peripheral bearing surface at the connection side shaft end of the screw tube shaft. The connecting member and the engaging claw, both connecting members are fitted in the inner peripheral bearing surface and the outer peripheral bearing surface, and the engaging groove and the engaging claw are engaged in the circumferential direction of the screw tube shaft. Hold on.

  Moreover, the screw pump described in Patent Document 2 is divided into a plurality of screws in the rotational axis direction, and a connecting shaft is interposed between the upper stage side screw and the lower stage side screw, and this connecting shaft is used as a bearing. And support.

Japanese Utility Model Sho 61-10979 Utility Model 1-76573

  In general, the screw pump described above is disposed by submerging only the inlet portion on the lower side of the screw 1 installed obliquely. For this reason, when handling corrosive water, such as seawater, the case where only the outer periphery of the screw blade | wing 8 corroded by the secular change especially in an entrance part is seen occasionally. When the outer diameter of the screw blade 8 is greatly lost, the gap between the outer peripheral edge of the screw blade 8 and the trough 9 is increased, and the discharge amount of the pump is reduced.

  For this reason, as shown in FIG. 11, after removing the outer peripheral edge 10 of the damaged part of the screw blade 8, the repair member 11 is welded and fixed to the outer peripheral side of the screw blade 8 to repair the outer diameter of the screw. There is a way.

  However, since this repair method is a simple repair method performed locally, it cannot be said that it is a sufficient recovery measure from a long-term viewpoint. Further, the work for correcting the balance around the rotational axis of the screw 1 and the work for correcting the bending state of the screw blade 8 at the repaired location can be performed only in an emergency manner.

As another repair method, there is a repair method for repairing the outer diameter of the screw blade 8 by repairing by welding when the outer diameter of the screw blade 8 is small.
This method takes man-hours for the quality of the work, and builds up on the old deteriorated base material, so it cannot be said to restore the original state.

  Furthermore, as another repair method, there is a method of replacing the screw 1 with a new one. In this case, since existing parts other than the screw 1 are diverted except for worn parts, it takes a lot of time to adjust the combination of the new screw 1 and the existing part, which causes an increase in cost.

  Further, since the screw pump has a small discharge amount instead of the size of the screw blade, it is inevitable that the screw pump becomes large in order to increase the discharge amount. For this reason, it is often difficult to carry the screw pump into and out of the installation site. In particular, when many years have passed since installation, the surroundings of the installation location may be residential, making it difficult for large vehicles to carry the screw pump, and bringing the screw pump back to the factory. It became impossible and the screw could not be repaired at the factory.

  Furthermore, as a case of a screw pump with a large diameter (blade outer diameter of about 3000 mm) that had to be repaired after about 30 years from the start of operation, the operation time was not so much, so the overall corrosion damage was significant. In many cases, only the blade entrance is severely damaged by corrosion.

  For this reason, it is desirable to replace only a portion where the corrosion damage of the screw is great with a new one. However, when the screw is divided into a plurality of divided parts, if the screw is a combination of a new divided part and an existing divided part, when the screw is divided into all new parts, In any case, there is a difficulty described below in ensuring the continuity between the screw blades of one divided portion and the screw blades of the other divided portion.

  The screw blade is obtained by continuously joining a plurality of blade pieces embossed and molded on the outer peripheral surface of a screw pipe and welding and fixing them. Even if the material, thickness, and the like of the raw metal plate are the same, the blade piece having a curved surface that has been embossed is not necessarily finished in the same shape as a molded product, and has an error.

  When a plurality of blade pieces with such errors are simply joined together, a slight shift occurs in the spiral angle of the blades at each position in the axial direction of the screw pipe. It is finished in a predetermined spiral shape by adjusting the angle and length.

  However, when the screw is divided into a plurality of divided parts, the screw blades are interrupted at the ends of the divided parts. It becomes difficult. For this reason, the end portion of the screw blade in the divided portion cannot maintain the spiral angle with respect to the rotation axis of the spiral blade as it should be, and at the connection portion between one divided portion and the other divided portion. The ends of both screw blades do not match, and it is difficult to ensure continuity between the screw blades of one divided portion and the screw blades of the other divided portion.

  For this reason, the screw is temporarily assembled at the factory, and the screw blade spiral angle, screw rotation balance, and the like are adjusted. However, when disassembling the screw into a plurality of divided parts and reassembling them after transporting, it is difficult to reproduce the relative position of the one divided part and the other divided part around the rotation axis in the temporarily assembled state. If there is a slight misalignment even if the relative position around the rotation axis is aligned based on the inner peripheral edge of the blade fixed by welding on the outer peripheral surface of the screw pipe, there will be a large misalignment at the outer peripheral edge of the blade. .

  The present invention solves the above-mentioned problems, and by making it possible to accurately reproduce the relative position around the rotation axis between the divided portions to be interconnected, the reproducibility of the screw blade continuity, rotation balance, etc. It aims at providing the screw pump which can be ensured, and a manufacturing method.

  In order to solve the above-described problems, a screw pump manufacturing method according to the present invention includes an existing screw having screw blades arranged on the outer peripheral surface of a screw shaft, a replacement portion on the screw inlet side and a screw outlet in the rotational axis direction. In the manufacturing process, a new split screw that replaces the replacement part in the manufacturing process is manufactured by arranging split screw blades on the outer peripheral surface of the split screw shaft, and the remaining part screw is divided into the existing parts. In the adjustment process, the new split screw and the existing split screw that are connected to each other are placed in a state where both ends face each other, and the relative position around the rotation axis of both split screws is positioned. Adjusting and positioning in the circumferential direction between the opposing ends of both split screws, relative position around the rotation axis of both split screws In this state, adjustment is performed as a screw to achieve an adjusted state.In the conveying process, the screw positioning means is released and transferred to the installation location in the form of a plurality of divided screws. The direction positioning means positions the relative position of the two split screws around the rotation axis, and the connecting and fixing means connects the ends of both split screws in the direction of the rotation axis to reproduce the adjusted state. Features.

  The screw pump manufacturing method according to the present invention includes a screw pump in which screw blades are arranged on the outer peripheral surface of the screw shaft, and can be divided into a plurality of divided screws in the rotational axis direction. The divided screw is manufactured by arranging divided screw blades on the outer peripheral surface of the divided divided screw shaft, and in the adjusting process, the divided screws connected to each other are arranged so that both ends face each other. The relative position of the split screw around the rotation axis is adjusted by the circumferential positioning means provided between the opposing ends of both split screws. In this state, the adjustment work as a screw is performed to obtain an adjusted state. It is released and transferred to the installation location in the form of multiple split screws. In the installation process, the circumferential positioning means positions the relative position around the rotation axis of both split screws, and the connection fixing means splits both. The adjusted state is reproduced by connecting the end of the screw in the direction of the rotation axis.

  In the screw pump manufacturing method of the present invention, in the adjustment step, after positioning by the circumferential positioning means, the ends of both split screws are connected in the direction of the rotation axis by the connecting and fixing means, and in this state as the screw It is characterized by performing an adjustment operation to be in an adjusted state.

  In the screw pump manufacturing method according to the present invention, in the adjusting step, the circumferential positioning means is configured such that when the reference pin is removably attached to the first reference hole drilled at the end of one of the split screws, the reference pin is pinned. In a state in which it is detachably mounted in the second reference hole of the seat, the seat for the pin is loosely fitted in the seat holding hole drilled in the end of the other split screw, and the reference pin is placed at the end of both split screws. The pin seat is fixed to the end of the other split screw while being positioned with respect to the portion.

  In the manufacturing method of the screw pump according to the present invention, in the installation step, the adjusting screw blades that fill the gaps between the ends of both divided screw blades are installed, and the divided screw blades are arranged in a continuous spiral shape. Features.

  The screw pump of the present invention includes a screw having a screw blade spirally disposed on the outer peripheral surface of a screw shaft, the screw is divided into a plurality of divided screws in the direction of the rotation axis, and each divided screw is divided. A circumferential positioning means having a split screw shaft and split screw blades, and positioning relative positions around the rotation axis of both split screws between the opposite ends of the mutually connected split screws; It has a connection fixing means which connects the edge part of both division screws in the direction of a rotation axis.

  In the screw pump of the present invention, the circumferential positioning means includes a first reference hole drilled in an end portion of one split screw, a reference pin that comes into close contact with the first reference hole, and an end portion of the other split screw. A seat holding hole drilled in, a pin seat that is loosely fitted in the seat holding hole, and fixed to the end of the other split screw, and a pin seat is drilled so that the reference pin can be detached. A second reference hole is provided.

  The screw pump of the present invention is characterized by having an adjustment screw blade that fills a gap between the ends of both divided screw blades.

  As described above, according to the present invention, by providing the circumferential positioning means for positioning the relative positions of the two divided screws around the rotational axis, the relative positions of the rotational axes around the interconnecting divided parts can be accurately determined. Even if the screw is divided and manufactured, reproducibility such as continuity of the screw blades and rotation balance can be secured.

Sectional drawing which shows the junction part of the division | segmentation screw in embodiment of this invention Sectional drawing which shows the circumferential direction positioning means in the same embodiment Schematic diagram showing the packaging of the screw upon arrival at the factory Schematic diagram showing joint processing Schematic diagram showing the packaging of the screw after factory production Schematic diagram showing the screw packaging during factory temporary assembly Schematic diagram showing centering adjustment and balance adjustment work Schematic diagram showing the package of the screw when leaving the factory Schematic diagram showing a conventional screw pump Schematic diagram showing the installation state of a conventional screw pump Schematic diagram showing the repaired state of a conventional screw pump

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The basic structure of the screw pump of the present invention is the same as that described above with reference to FIGS. 9 and 10, and members having the same functions will be described with the same reference numerals.

  As shown in FIGS. 1 to 8, the screw 510 is divided into a plurality of divided screws 511 and 512 in the direction of the rotation axis, and each divided screw 511 and 512 is divided into divided screw shafts 521 and 522, and Divided screw blades 531 and 532 are provided.

  Joining flanges 541 and 542 forming joining portions are provided at both ends facing each other between the divided screws 511 and 512 connected to each other. The joint flanges 541 and 542 have spigot portions 551 and 552 that are fitted to each other on opposite surfaces.

  The joining flanges 541 and 542 are provided with circumferential positioning portions 560 that constitute circumferential positioning means for positioning relative positions of both divided screws 511 and 512 around the rotation axis, and ends of both divided screws 511 and 512. A connection fixing portion 570 is provided as connection fixing means for connection in the direction of the rotation axis. The connection fixing part 570 includes a bolt 571 and a nut 572.

  As shown in FIG. 2, the circumferential positioning portion 560 has a first reference hole 561 drilled in the joining flange 541 at the end of one split screw 511 and a reference that is detachably in contact with the inside of the first reference hole 561. A pin 562, a seat holding hole 563 drilled in a joint flange 542 at the end of the other split screw 512, and a seat flange formed in the seat holding hole 563 so as to be loosely fitted, and a joint flange at the end of the other split screw 512 A pin seat 564 fixed to the pin 542 and a second reference hole 565 that is perforated in the pin seat 564 so that the reference pin 562 is detachably attached.

  The reference pin 562 has a tapered shape, but may have a straight body shape. The reference pin 562 has a bolt portion 566 at the head, and a nut portion 567 is disposed by screwing into the bolt portion 566.

There are two methods for manufacturing the screw pump: a method for renovating existing ones and creating a new one, and a method for creating all new ones.
First, I will explain how to renovate existing ones and create new ones.
-Field work In the screw pump in the state shown in FIG. 9, the upper spindle 21 and the lower spindle 22 are removed from the screw 1, and the screw 1 is lifted up by a crane and placed horizontally on the ground.

  Then, the screw 1 is cut and divided into a damaged replacement part 1a on the screw inlet side and a healthy remaining part 1b on the screw outlet side in the rotational axis direction. At this time, the cutting position is set in consideration of the damage situation and the transportation conditions.

The divided replacement part 1a, remaining part 1b, upper spindle 21 and lower spindle 22 of the divided screw 1 are transported to the factory. At this time, since the screw 1 is divided into a plurality of parts, the pump parts can be easily transported even from a confined site where transportation conditions are poor, and repair at the factory is possible.
-Remodeling work Fig. 3 shows the package of the screw 1 upon arrival at the factory.
In the manufacturing process, a new split screw 511 to be replaced with the replacement portion 1a is manufactured by arranging the split screw blades 531 in a spiral shape on the outer peripheral surface of the split screw shaft 521, and the remaining portion 1b of the screw 1 is split into the split screw 512. Use as

  In this way, by newly creating the replacement part 1a on the screw inlet side where the corrosion is severe, not only the missing blades but also the pipe part where the corrosion has progressed is replaced. be able to. Since the new split screw 511 is disposed on the screw inlet side and is always immersed in the liquid to be transported, it is easily corroded and worn. For this reason, the new split screw 511 can be made of stainless steel having high corrosion resistance, and can be sprayed or coated with heavy anticorrosion to improve wear resistance and corrosion resistance.

Moreover, since the healthy part is diverted and only the corrosion damaged part is replaced and the factory is repaired, it is possible to return it to its original form.
As shown in FIG. 4, joint flanges 541 and 542 are disposed at the ends of the new split screw 511 and the existing split screw 512, and both are fixed by welding by adjusting the parallelism and the axis.

  A new split screw 511 and an existing split screw 512 that are connected to each other are arranged so that both ends thereof face each other, and the relative positions of both split screws around the rotation axis are adjusted, and both split screws are arranged. The positions of the blades 531 and 532 are aligned. In this state, assuming the finished dimensions of the connection flanges 541 and 542, the center position of the hole through which the bolt 571 of the coupling fixing portion 570 is inserted is determined, and the first reference hole 561 and the seat holding hole 563 of the circumferential positioning portion 560 are determined. Decide where to place.

Since the split screw blades 531 and 532 have a large “displacement” on the blade outer peripheral edge side, the continuity of both split screw blades 531 and 532 is adjusted by correction. At this time, adjustment is made so that there is a slight gap between the end portions of both split screw blades 531 and 532.
-Machining work Each split screw 511, 512 is processed into a flange surface, inlay processing, bolt hole processing, etc. with a large lathe or a horizontal lathe. Check that there are no defects in the results of machining and remodeling work.
・ Temporary assembly work (adjustment process)
As shown in FIGS. 5 and 6, a new split screw 511 and an existing split screw 512 that are connected to each other are arranged in a state in which both ends face each other, and around the rotation axis of both split screws 511 and 512. The circumferential positions of the two split screws 511 and 512 are adjusted by the circumferential positioning portions 560 provided between the joint flanges 541 and 542 at the opposite ends of the split screws 511 and 512. After positioning the surrounding relative positions, the bolts 571 and the nuts 572 of the connection fixing portion 570 are fastened, and the ends of both the split screws 511 and 512 are connected in the direction of the rotation axis.

  When the reference pin 562 is detachably attached to the first reference hole 561 drilled in the joint flange 541 at the end of one split screw 511, the circumferential positioning portion 560 attaches the reference pin 562 to the first of the pin seat 564. 2 With the reference hole 565 detachably mounted, the pin seat 564 is loosely fitted in the seat holding hole 563 drilled in the joint flange 542 at the end of the other split screw 512, and the reference pin 562 is the first 1 Insert into the reference hole 561.

  At this time, the relative positions of the two split screws 511 and 512 around the rotation axis are adjusted, and the continuity of the split screw blades 531 and 532 can be realized between the split screws 511 and 512. However, the first reference hole 561 may not correspond to the center of the seat holding hole 563. However, since there is an adjustment gap between the seat holding hole 563 and the pin seat 564, the positions of the pin seat 564 and the reference pin 562 are adjusted within the adjustment range allowed for the adjustment gap, and the second It is possible to adjust the position of the reference hole 565 to the position facing the first reference hole 561 by matching the actual object.

  Next, in a state where the reference pin 562 is positioned with respect to the joining flanges 541 and 542 of both split screws 511 and 512, the pin seat 564 is fixed to the joining flange 542 at the end of the other split screw 512.

  With this configuration, when the divided screws 511 and 512 are disassembled and later reassembled, the reference pins 562 are attached to the first reference hole 561 and the second reference hole 565, so that the state before disassembly can be accurately reproduced.

  As shown in FIG. 7, the upper spindle 21 and the lower spindle 22 are attached to both ends of the joined divided screws 511 and 512, and centering confirmation is performed. A gap between the ends of the split screw blades 531 and 532 is confirmed, and a member for filling the gap is prepared as necessary.

  Further, it is confirmed and adjusted that the blade outer diameters of the divided screw blades 531 and 532 are within the tolerance in the entire length in the rotation axis direction. Further, the balance around the rotation axis is confirmed, and if necessary, additional mass is provided inside the split screw shafts 531, 522, and in this state, an adjusted state as a screw is obtained.

As shown in FIG. 8, in the transporting process, the upper spindle 21 and the lower spindle 22 are disconnected, the divided screws 511 and 512 are disconnected, disassembled into parts, and a painting operation is performed to transport to the site.
・ Field work (installation process)
After carrying the upper spindle 21, the lower spindle 22, and the divided screws 511, 512 into the field, the circumferential positioning unit 560 positions the relative positions of the divided screws 511, 512 around the rotation axis, and then the connection fixing unit 570. Then, the ends of both split screws 511 and 512 are connected in the direction of the rotation axis to reproduce the adjusted state.

  Thereafter, the end portions of the split screw blades 531 and 532 of both split screws 511 and 512 are welded. Here, a member that fills the gap between the end portions prepared in the temporary assembly work is welded between the end portions of the divided screw blades 531 and 532, and the divided screw blades 531 and 532 are used as a continuous integral screw blade. Then, the assembled screw is placed inside the trough 9 in the reverse order of disassembly, and the upper spindle 21 and the lower spindle 22 are supported by bearings.

  In the above-described embodiment, the manufacturing method of the screw pump that modifies the existing one and newly creates a part is shown. However, the manufacturing method of the screw pump that completely renovates the whole is almost the same. The difference is that the existing split screw 512 is newly created.

  As described above, by providing the circumferential positioning portion 560 that positions the relative positions of the split screws 511 and 512 around the rotation axis, the relative position of the rotation shaft center between the divided portions connected to each other can be accurately determined. Even if the screw is divided and manufactured, the reproducibility of the screw blade continuity, rotation balance, etc. can be secured.

  When setting the circumferential position portion 560 in the adjustment step, there is an adjustment gap between the seat holding hole 563 and the pin seat 564, and the pin seat 564 having the second reference hole 565 is divided into the other part. Since it is arranged so as to be loosely fitted in the seat holding hole 563 drilled at the ends of the screws 511 and 512, the relative position of the two split screws 511 and 512 around the rotation axis is adjusted, and both split screws 511, Even if the first reference hole 561 does not correspond to the center of the seat holding hole 563 in a state in which the continuity of the divided screw blades 531 and 532 can be realized between 512, the adjustment gap is allowed. Within the adjustment range, the positions of the pin seat 564 and the reference pin 562 are adjusted, and the position of the second reference hole 565 is adjusted to the position opposite to the first reference hole 561 by adjusting the actual object. It is a function.

  The circumferential positioning means is not limited to this embodiment, and various methods can be adopted.

510 Screws 511, 512 Split screws 521, 522 Split screw shafts 531, 532 Split screw blades 541, 542 Joint flanges 551, 552 Spiral positioning part 560 Circumferential positioning part 570 Bolt 572 Nut 561 First reference hole 562 Reference pin 563 Seat holding hole 564 Pin seat 565 Second reference hole 566 Bolt part 567 Nut part

Claims (8)

The existing screw having screw blades arranged on the outer peripheral surface of the screw shaft is divided into a replacement part on the screw inlet side and a remaining part on the screw outlet side in the rotational axis direction,
In the manufacturing process, a new split screw to replace the replacement part is manufactured by arranging the split screw blade on the outer peripheral surface of the split screw shaft, and the remaining part screw is remodeled as an existing split screw,
In the adjustment process, the new split screw and the existing split screw that are connected to each other are placed so that both ends face each other, and the relative positions of both split screws around the rotation axis are adjusted, With the circumferential positioning means provided between the opposing ends of the split screw, the relative position around the rotation axis of both split screws is positioned. ,
In the transport process, release the screw positioning means and transfer to the installation location in the state of multiple split screws,
In the installation process, the relative position around the rotation axis of both split screws is positioned by the circumferential positioning means, and the ends of both split screws are connected in the direction of the rotation axis by the connecting and fixing means and adjusted. A method of manufacturing a screw pump characterized by reproducing the above. In the production of a screw pump in which a screw having screw blades arranged on the outer peripheral surface of the screw shaft can be divided into a plurality of divided screws in the direction of the rotation axis,
In the manufacturing process, each divided screw is manufactured by arranging divided screw blades on the outer peripheral surface of the divided screw shaft,
In the adjustment process, the split screws that are connected to each other are arranged so that both ends face each other, the relative positions around the rotation axis of both split screws are adjusted, and the opposite ends of both split screws With the circumferential positioning means provided between the parts, the relative position around the rotation axis of both split screws is positioned, and in this state the adjustment work as a screw is performed and the adjusted state is established.
In the transport process, release the screw positioning means and transfer to the installation location in the state of multiple split screws,
In the installation process, the relative position around the rotation axis of both split screws is positioned by the circumferential positioning means, and the ends of both split screws are connected in the direction of the rotation axis by the connecting and fixing means and adjusted. A method of manufacturing a screw pump characterized by reproducing the above.   In the adjustment step, after positioning by the circumferential positioning means, the ends of both split screws are connected in the direction of the rotation axis by the connecting and fixing means, and in this state, adjustment work as a screw is performed to obtain an adjusted state. The method for manufacturing a screw pump according to claim 1 or 2, wherein   In the adjusting step, the circumferential positioning means can be detached from the second reference hole of the pin seat when the reference pin is removably attached to the first reference hole drilled at the end of one split screw. In the state where the pin seat is loosely fitted in the seat holding hole drilled in the end of the other split screw and the reference pin is positioned with respect to the ends of both split screws, The screw pump manufacturing method according to any one of claims 1 to 3, wherein the seat is fixed to an end of the other split screw.   The installation step includes installing screw blades for adjustment that fill a gap between the ends of both divided screw blades, and arranging the divided screw blades in a continuous spiral shape. A method for manufacturing the screw pump according to claim 1.   The screw shaft is provided with a screw spirally disposed on the outer peripheral surface of the screw shaft, and the screw is divided into a plurality of divided screws in the rotational axis direction. Each divided screw is divided into divided screw shafts and divided screw blades. A circumferential positioning means for positioning a relative position around the rotation axis of both split screws between the ends facing each other between the mutually connected split screws, and ends of both split screws A screw pump, characterized in that it has coupling fixing means for connecting them in the direction of the rotational axis.   The circumferential positioning means includes a first reference hole drilled in an end of one split screw, a reference pin that is detachably in contact with the first reference hole, and a seat holding hole drilled in an end of the other split screw. A pin seat that is loosely fitted in the seat holding hole and fixed to the end of the other split screw, and a second reference hole that is perforated in the pin seat so that the reference pin is releasably in contact with the pin seat. The screw pump according to claim 6.   8. The screw pump according to claim 6, further comprising an adjusting screw blade that fills a gap between the ends of both divided screw blades. 9.

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