JP2006152896A - Synthetic resin molded centrifugal pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin molded centrifugal pump, in which a clearance size between contact faces of an internal casing and a back casing is reduced, and a clearance size between a front end of a blade and an internal casing inner face opposed to a centrifugal impeller of the internal casing is set to be within a mounting size of a mechanical seal. <P>SOLUTION: In the synthetic resin molded centrifugal pump, a synthetic resin molded internal casing 11 is disposed in a synthetic resin molded pump casing 1, and the internal casing 11 is disposed to face the synthetic resin molded centrifugal impeller 30 and is abutted on and fixed to the back casing 8. Dimensional accuracy of the internal casing inner face 11c facing the centrifugal impeller 30 and dimensional accuracy of a contact face 11b of the internal casing 11 abutted on and fixed to the back casing 8 are finished by machining so that the faces become highly accurate faces. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, a pump casing, a guide vane (referred to as an “inner casing” in the present invention), a back casing, and a spiral centrifugal impeller are molded from synthetic resin, and the centrifugal impeller is opened on the front side. The present invention relates to a synthetic resin centrifugal pump that is a semi-open type and has an inner casing disposed opposite to a centrifugal impeller and fixed in contact with a back casing inside the pump casing.

  Various types of centrifugal pumps have been developed by the applicant (see, for example, Patent Document 1). By the way, in a centrifugal pump that handles seawater and chemical liquids, when wetted parts such as pump casings and centrifugal impellers are made of metallic materials such as cast iron and stainless steel, the wetted parts touch seawater and chemical liquids, causing rust and corrosion. There is a bug that causes For this reason, the spiral pump which shape | molded the pump casing and the centrifugal impeller with the synthetic resin is known.

  In this synthetic resin pump, an ordinary centrifugal impeller includes a back plate, a front plate that is spaced apart from the back plate and has an opening in the center, and a radial direction between the back plate and the front plate. A plurality of blades extending in a spiral shape. When such a centrifugal impeller is rotated by a drive shaft connected to the center portion, a liquid is introduced into the impeller from an opening of the front plate, and the liquid is pressurized through a passage between the blades. A liquid is sent out to the outer peripheral part from the discharge outlet opened on the spiral spiral side in the radial direction of the blade.

  On the other hand, there is a semi-open structure pump in which the front side of the centrifugal impeller is opened. As shown in FIG. 6, the semi-open centrifugal impeller 30 includes a back plate 42 and a plurality of blades 43 extending spirally in the radial direction on the front surface of the back plate 42. There is no structure and the front side is open.

  Therefore, a semi-open centrifugal pump will be described. As shown in FIG. 2, a semi-open centrifugal impeller 30 and a centrifugal impeller 30 facing the centrifugal impeller 30 are disposed inside the pump casing 1. It has an inner casing 11 in arrangement. The inner casing 11 is provided with a spiral passage 44 on the outer periphery of the centrifugal impeller 30, further surrounds the outer periphery, extends to the back side, and contacts the back casing 8. Liquid that is pumped through the spiral passage 44 is discharged from the discharge port 45 of the inner casing 11. In this case, the pumping efficiency of the pump depends on the position of the discharge port 45 of the inner casing 11 shown in FIG.

  In general, a centrifugal pump with a semi-open structure is provided with a recess on the contact surface for fixing the back casing and a protrusion on the fixing surface of the inner casing to be combined with the inner casing. It has a structure that fixes the mating position.

  By the way, in such a semi-open type centrifugal pump, for example, the gap dimension A (shown in FIG. 2) between the contact surface 11b of the inner casing 11 and the contact surface 8b of the back casing 8 and the blade front end of the blade 43 The gap dimension B (shown in FIG. 2) between 43a and the inner casing inner surface 11c facing the centrifugal impeller 30 of the inner casing 11 greatly affects the pumping performance of the pump.

  First, considering the former gap dimension A, when the gap dimension A between the contact surface 11b of the inner casing 11 and the contact surface 8b of the back casing 8 is large, the gap 46 is pressurized in the passage 46 between each blade of the impeller 30. When the discharged liquid is discharged from the discharge port 45 of the inner casing 11 along the wall surface of the inner casing 11, the liquid leaks from the gap dimension A between the contact surface 11 b of the inner casing 11 and the contact surface 8 b of the back casing 8. Pumping efficiency decreases. Next, considering the latter gap dimension B, when the gap dimension B between the blade front end 43a of the blade 43 and the inner casing inner surface 11c facing the centrifugal impeller 30 of the inner casing 11 is large, each blade of the impeller 30 When the liquid pressurized in the passage 46 is leaked, the pumping efficiency of the pump is lowered, and when the gap size B is small, the wall resistance is increased and the rotational efficiency of the impeller 30 is lowered.

  For this reason, the clearance dimension A between the contact surface 11 b of the inner casing 11 and the contact surface 8 b of the back casing 8, and between the blade front end 43 a of the blade 43 and the inner casing inner surface 11 c of the inner casing 11 facing the centrifugal impeller 30. The gap dimension B must be managed with high accuracy. Therefore, as a method of adjusting the gap dimension B between the blade front end 43a of the blade 43 and the inner casing inner surface 11c facing the centrifugal impeller 30 of the inner casing 11, as shown in FIG. An adjustment shim 33 is interposed between the portion 28 a and the impeller 30, and the gap dimension B is adjusted by changing the thickness of the adjustment shim 33.

  Further, a mechanical seal 34 is used as the shaft seal device. The mechanical seal 34 includes a rotation side mechanical seal 34a and a fixed side mechanical seal 34b. As shown in FIG. 2, the rotation side mechanical seal 34 a is installed on the back side of the back plate 42 of the impeller 30, and the fixed side mechanical seal 34 b is installed on the front side of the back casing 8. The mechanical seal 34 has a mechanical seal mounting dimension C determined. If this mounting dimension C is not observed, liquid leakage will occur from the mechanical seal 34 and the pumping efficiency will decrease. For this reason, it is necessary to manage the mounting dimension C of the mechanical seal.

  By the way, this kind of semi-open type centrifugal pump that handles seawater and chemical liquid uses resin molded parts, so the dimensional accuracy of each part is regulated by molding, and raising the dimensional accuracy is not possible. difficult. Therefore, there is a concern that the gap dimension A between the contact surface 11b of the inner casing 11 and the contact surface 8b of the back casing 8 is increased. Further, when adjusting the gap dimension B between the blade front end 43a of the blade 43 and the inner casing inner surface 11c facing the centrifugal impeller 30 of the inner casing 11, the mechanical seal 34 does not fall within the mounting dimension of the mechanical seal 34. There is a problem that liquid leakage occurs.

Japanese Patent Application No. 3002-365762

  The problem to be solved by the present invention is to solve the above-mentioned problem, and the gap between the contact surface of the inner casing and the contact surface of the back casing can be managed to be small, and the front end of the blade and the centrifugal blade of the inner casing A synthetic resin spiral pump capable of managing a gap dimension so as to be within a mounting dimension of a mechanical seal even when adjusting a gap dimension between an inner casing inner surface facing a vehicle.

  According to a first aspect of the present invention, a synthetic resin molded inner casing is disposed in a pump casing molded from a synthetic resin, and the inner casing is made of a synthetic resin molded centrifuge. In the centrifugal pump that is disposed opposite to the impeller and fixed in contact with the back casing, the dimensional accuracy of the inner casing inner surface that faces the centrifugal impeller and the contact surface of the inner casing that contacts and fixes the back casing. A centrifugal pump made of synthetic resin, characterized in that each of the dimensional accuracy is finished to a highly accurate surface by machining.

  In the invention of claim 2, a concave hole is provided in the contact surface of the inner casing that contacts and is fixed to the back casing, and a convex protrusion is provided at a position of the back casing corresponding to the concave hole of the inner casing. The convex projection of the back casing is inserted into the concave hole of the contact surface of the casing, the inner casing is contacted and fixed to the back casing, and the dimensional accuracy of the contact surface of the back casing is fixed by contacting the inner casing. The synthetic resin molded centrifugal pump according to claim 1, wherein the surface is finished with high precision by machining.

  According to a third aspect of the present invention, a concave hole is provided on both sides of the contact surface between the back casing and the inner casing that are in contact and fixed, and a pin is inserted into the concave hole so that the back casing and the inner casing are in contact with each other. The synthetic resin-molded centrifugal pump according to claim 1, wherein the dimensional accuracy of the contact surface of the back casing that contacts and fixes the inner casing is finished to a highly accurate surface by machining. It is.

  The operation of the above means will be described. According to the first aspect of the present invention, the inner casing inner surface facing the centrifugal impeller of the inner casing and the contact surface of the inner casing with the back casing are finished to a highly accurate surface by machining, whereby the dimensions of the inner casing are obtained. The accuracy can be increased and the mechanical seal can be accommodated within the mounting dimensions. As a result, the liquid leakage prevention effect is improved and the pumping characteristics of the pump are not affected. Furthermore, the gap dimension A between the fixed surface of the inner casing and the fixed surface of the back casing can be reduced, and the pumping characteristics of the pump are not affected.

  According to the invention of claim 2, the position of the inner casing can be fixed by providing a concave hole on the contact surface of the inner casing and providing a convex projection on the back casing and fitting each other. Pumping characteristics are not affected. Furthermore, by providing a concave hole in the contact surface of the inner casing, there is no protrusion, so that the contact surface can be easily made into a highly accurate surface by machining, whereby the contact surface of the inner casing and the back casing Even when the gap dimension A between the front surface of the impeller and the inner casing inner surface facing the centrifugal impeller of the inner casing is adjusted, the gap dimension A with the contact surface of the inner seal can be controlled to be even smaller. It can be managed to fit within the mounting dimensions, and the pumping characteristics of the pump will not be affected.

  According to the invention of claim 3, it is possible to fix the position of the inner casing by providing a concave hole both facing the contact surface of the back casing and the inner casing, and inserting and fitting a pin into the concave hole. The pumping characteristics of the pump are not affected. Furthermore, providing both concave holes facing the contact surfaces of the back casing and the inner casing can make the contact surfaces both highly accurate surfaces by machining, thereby reducing the fixed surface of the inner casing. The gap dimension A with the fixed surface of the back casing can be managed to be even smaller, and the gap dimension B between the front surface of the impeller and the inner casing can be adjusted so that it is within the mounting dimensions of the mechanical seal. The pumping characteristics of the pump are not affected.

  As described above, according to the present invention, since the inner casing inner surface facing the centrifugal impeller and the contact surface fixed to the back casing are machined with respect to the inner casing, the dimensional accuracy of the inner casing is increased. Is possible. Furthermore, since the contact surface with the inner casing is machined with respect to the back casing, the dimensional accuracy of the back casing can be increased. In other words, it is possible to improve the accuracy of adjusting the gap between the inner casing and the blade front end of the centrifugal impeller, and to reduce the variation in the gap between the inner casing and the back casing and the mounting dimensions of the mechanical seal. As a result, the present invention has excellent effects such as suppressing a decrease in pumping characteristics of the pump and preventing water leakage from the mechanical seal.

  The best mode for carrying out the present invention will be described with reference to the drawings. In the spiral centrifugal pump shown in FIGS. 1 and 2, the pump casing 1 is molded from a synthetic resin such as PPE resin. As shown in FIG. 2, the synthetic resin pump casing 1 is provided with a suction port 2 in the center of the front surface, and a suction flange pipe joint 3 is fixed with bolts 4 so as to face the suction port 2. ing. A pump discharge port 5 is provided on the upper surface of the pump casing 1, and a discharge flange fitting 6 is fixed by a bolt 7 so as to face the discharge port 5. As shown in FIG. 1, a back casing 8 made of synthetic resin such as PPE is fitted to the back surface of the pump casing 1, and this back surface is fixed to the back casing 8 by bolts 9. Further, an inner casing 11 having a suction port 10 at the center is installed inside the pump casing 1 so as to face the back casing 8, and is further fixed to the back casing 8 by bolts 12. This fixing method will be described later.

  A suction pipe and a discharge pipe (not shown) are connected to the suction flange pipe joint 3 and the discharge flange pipe joint 6. A valve seat 13 is provided on the inner end face of the suction flange pipe joint 3, and a valve body 14 constituting a one-way valve is detachably seated on the valve seat 13. The valve body 14 is provided with a packing portion 15 around it, and the packing portion 15 is sandwiched between the suction flange pipe joint 3 and the pump casing 1. And the valve body 14 has a structure which contacts / separates to the valve seat 13 when the base part of the packing part 15 elastically deforms. As a result, when fluid pressure is applied to the inside of the pump casing 1, the valve seat 13 is seated and the suction port 2 is closed.

  A partition wall 16 is provided inside the pump casing 1, and a passage 17 connected to the suction port 10 of the inner casing 11 exists in the partition wall 16. The end of the partition wall 16 is fitted to the inner casing 11 via an O-ring 18. A gas-liquid separation chamber 19 surrounded by the wall surface of the pump casing 1 is provided on the outer periphery of the partition wall 16.

  As shown in FIG. 2, a priming port 20 is provided at the upper part of the pump casing 1 adjacent to the discharge port 5. A priming cap 21 is installed at the priming port 20 to close the priming port 20. In addition, a drain port 22 is provided in the lower part of the pump casing 1 and is normally closed by installing a drain cap 23 on the drain port 22.

  Further, as shown in FIG. 1, the back casing 8 is fitted with a bracket 24 on the back side and fixed with a bolt 25, and the bracket 24 is fixed to an electric motor 26 with a bolt 27. The electric motor 26 includes a driving shaft 28 that is integral with the electric motor shaft, and this driving shaft 28 is introduced into the pump casing 1 through a driving shaft inlet 29 provided in the center of the back casing 8. A centrifugal impeller 30 is fixed to the tip of the drive shaft 28 by a fixing nut 31 so as to face the inner casing 11. As shown in FIG. 8, the centrifugal impeller 30 has a drive shaft mounting hole 32 through which the drive shaft 28 is penetrated, and a fixing nut 31 is screwed to the tip of the penetrated drive shaft 28. The centrifugal impeller 30 is fixed by tightening. At this time, the drive shaft 28 is provided with a step portion 28a for regulating the position of the centrifugal impeller 30, and an adjustment shim 33 is provided between the step portion 28a of the drive shaft 28 and the centrifugal impeller 30 as necessary. By intervening, the position of the centrifugal impeller 30 can be adjusted.

  Here, FIGS. 8A and 8B show the structure of the centrifugal impeller 30. FIG. The centrifugal impeller 8 has the drive shaft mounting hole 32 through which the drive shaft 28 penetrates as described above, and has the circular back plate 42 around the drive shaft mounting hole 32, except for the central portion of the back plate 41. A spiral blade 43 is provided around the front plate 41 extending from the back plate 41 to the front side of the blade front end 43a, forming a semi-open impeller. In this embodiment, five blades 43 are provided. Is provided.

  Further, a mechanical seal 34 that is a shaft seal device is installed between the rear central portion of the centrifugal impeller 30 and the front central portion of the back casing 8, and the drive shaft 28 penetrates the mechanical seal 34. is set up. The mechanical seal 34 keeps the airtightness between the drive shaft 28 and the drive shaft introduction port 29.

  The drive shaft 28 is provided with a draining plate 35 on the back side of the drive shaft inlet 29 of the back casing 8. This is because, in the unlikely event that liquid leakage occurs from the mechanical seal 34, the liquid tries to penetrate the electric motor 26 through the drive shaft 28 by centrifugal force. The bracket 24 has a space 36 around the draining plate 35 so that the liquid repelled by the draining plate 35 can be discharged.

  Further, a base 38 is attached to the lower portion of the electric motor 26 with a bolt 37, and the base 38 is fixed to a fixed base 40 with a bolt 39.

  The inner casing 11 will be further described with reference to FIGS. The inner casing 11 is molded from a synthetic resin such as PPE resin, and the inner casing inner surface 11c facing the centrifugal impeller 30 and the contact surface 11b that contacts and fixes the back casing 8 are turned by machining. ing. First, the accuracy of the flatness of the contact surface of the inner casing 11 is increased by machining the contact surface 11b that contacts and fixes the back casing 8. As a result, the gap dimension A between the inner casing 11 and the back casing 8 is reduced, and an increase in water leakage from the gap can be prevented, and a reduction in pumping characteristics of the pump is suppressed.

  Further, by turning the inner casing inner surface 11c facing the centrifugal impeller 30 by machining, the gap dimension B between the inner casing 11 and the blade front end 43a of the centrifugal impeller 30 can be adjusted as small as possible. Thus, an increase in the amount of pumped water that leaks through the gap can be prevented, and a decrease in pumping characteristics of the pump is suppressed. Further, the inner casing inner surface 11c facing the centrifugal impeller 30 and the contact surface 11b fixed to the back casing 8 are both finished by machining the same width as much as possible, so that the dimensional accuracy of the inner casing 11 is increased and the mechanical seal 34 is improved. The variation of the width of the mounting dimension C is as small as possible, so that the mounting dimension C is always constant. As a result, an increase in water leakage from the mechanical seal 34 can be prevented, a reduction in pumping characteristics of the pump can be suppressed, and liquid intrusion into the electric motor 26 is further suppressed.

  Further, as shown in FIG. 4, the inner casing 11 is provided with three concave holes 11a, while the back casing 8 is provided with convex protrusions 8a as shown in FIG. It is. These are fitted and fixed as shown in FIG. 7A, and the inner casing 11 and the back casing 8 are further bolted from the front side of the inner casing 11 with bolts 12. As a result, the inner casing 11 can be attached to the back casing 8 and the position of the inner casing 11 can be accurately fixed, and the accuracy of the gap dimension A for the attachment of the inner casing 11 is increased. Can be suppressed.

  Moreover, the concave hole 8c is provided in the position of the back casing 8 shown in FIG. 6 corresponding to the three concave holes 11a of the inner casing 11 shown in FIG. Then, as shown in FIG. 7 (b), a pin 41 is inserted into the concave hole 11a of the inner casing 11 and the concave hole 8c of the back casing 8 facing this, and the fitted inner casing 11 and back casing 8 are fixed. Further, the inner casing 11 and the back casing 8 are bolted from the front side of the inner casing 11 with bolts 12. As in the case of FIG. 7A, the inner casing 11 is attached to the back casing 8, and the position of the inner casing 11 can be accurately fixed, so that the pumping characteristics of the pump can be prevented from deteriorating. Further, in the case where the position is fixed by the pin 41 shown in FIG. 7B, both the contact surface 11b of the inner casing 11 and the contact surface 8b of the back casing 8 do not have convex protrusions. The accuracy of the 8b and the contact surface 11b can be increased by machining very easily. Accordingly, the accuracy of the gap dimension A for mounting the inner casing 11 is increased, and the variation of the mounting dimension B of the mechanical seal 34 is reduced. As a result, an increase in water leakage from the mechanical seal 34 is prevented, and it is possible to further suppress the deterioration of pumping characteristics of the pump and the infiltration of liquid into the electric motor 26.

It is a figure which shows the structure of a semi-open type spiral centrifugal pump, and is a side view which partially cuts and shows a pump part. FIG. 2 is a front view of a pump casing showing, in cross section, only a priming port viewed from the front side of FIG. 1 in a semi-open type centrifugal pump. In the semi-open type centrifugal centrifugal pump, a detailed view showing a part of the internal structure of the pump portion in an enlarged manner shows a gap dimension A, a gap dimension B, and a mechanical seal attachment dimension C. It is detail drawing of the inner casing of a semi-open type centrifugal centrifugal pump, (a) is a view seen from the left side of (b), (b) is a cut sectional view of (a), (c) is a right side of (b) It is the figure seen from. It is detail drawing of the back casing which has a convex-shaped protrusion, (a) is the sectional drawing, (b) is the figure seen from the right side. It is detail drawing of the back casing which has a concave hole which fits a pin, (a) is the sectional drawing, (b) is the figure seen from the right side. FIG. 6 is a detailed view of the fitting of the inner casing and the back casing in the present invention, where (a) is a fitting with the back casing shown in FIG. 5 and (b) is a fitting with the back casing shown in FIG. 6. It is detail drawing of the semi-open type centrifugal impeller used for this invention, (a) is sectional drawing, (b) is a front view from the starboard side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump casing 1a Back part 2 Suction port 3 Suction flange fitting 4 Bolt 5 Discharge port 6 Discharge flange fitting 7 Bolt 8 Back casing 8a Convex protrusion 8b Contact surface 8c Concave hole 9 Bolt 10 Suction port 11 Inner casing 11a Concave hole 11b Contact surface 11c Inner casing inner surface 12 Bolt 13 Valve seat 14 Valve body 15 Packing portion 16 Partition wall 17 Passage to the inner casing 18 O-ring 19 Gas-liquid separation chamber 20 Nominal water port 21 Nominal water cap 22 Drainage port 23 Drainage cap 24 Bracket 25 Bolt 26 Electric motor 27 Bolt 28 Drive shaft 28a Step 29 Drive shaft inlet 30 Centrifugal impeller 31 Fixed nut 32 Drive shaft mounting hole 33 Adjustment shim 34 Mechanical seal 34a Rotation side mechanical seal 34b Fixed side mechanical seal 3 5 Draining plate 36 Space 37 Bolt 38 Base 39 Bolt 40 Fixed base 41 Pin 42 Back plate 43 Blade 43a Blade front end 44 Spiral passage 45 Discharge port 46 Passage between each blade A A gap size B gap size C Mechanical seal installation size

Claims (3)

  A centrifugal pump in which an inner casing made of synthetic resin is placed in a pump casing made of synthetic resin, the inner casing is placed opposite to the synthetic impeller-made centrifugal impeller, and fixed in contact with the back casing The dimensional accuracy of the inner surface of the inner casing facing the centrifugal impeller and the dimensional accuracy of the contact surface of the inner casing that contacts and fixes the back casing are each finished to a highly accurate surface by machining. Synthetic resin molded centrifugal pump.   A concave hole is provided in the contact surface of the inner casing that contacts and is fixed to the back casing, a convex protrusion is provided at a position of the back casing corresponding to the concave hole of the inner casing, and a concave hole in the contact surface of the inner casing. The convex projections of the back casing are inserted into the inner casing, the inner casing is abutted against the back casing and fixed, and the dimensional accuracy of the contact surface of the back casing that abuts and fixes the inner casing is increased by machining. The centrifugal pump made of synthetic resin molding according to claim 1, wherein the surface is finished.   Both the back casing and the inner casing are in contact with and fixed against the contact surface, and both are provided with a concave hole, and a pin is inserted into the concave hole to fix the back casing and the inner casing in contact with each other. 2. The synthetic resin-molded centrifugal pump according to claim 1, wherein the dimensional accuracy of the contact surface of the back casing for abutting and fixing is finished to a highly accurate surface by machining.

Images