JP4381010B2 - Centrifugal pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a single suction type centrifugal pump having a so-called closed impeller in which a plurality of blades are disposed on a main plate and a side plate is provided on the opposite side of the main plate across the blades. It is suitable as a sanitary pump used for liquid pumping.
[0002]
[Prior art and problems]
In the conventional centrifugal pump of this type, no publicly-known document can be cited, but since the impeller is integrally formed by casting, the inner surface of the impeller, that is, the inner surface of the main plate, the inner surface of the side plate, and the blades The finishing process for the side faces became very difficult, and the finishing process could not be performed sufficiently. Therefore, the finished surface roughness of the inner surface of the impeller (finished surface roughness) was poor. For this reason, in the conventional centrifugal pump, the soot of various liquids tends to adhere and remain on the inner surface of the impeller, which is not preferable in terms of hygiene.
[0003]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a spiral pump provided with an impeller having a structure that allows easy finishing of the inner surface of the impeller and good surface roughness in manufacturing the pump. And
[0004]
[Means for Solving the Problems]
The spiral pump according to the first aspect of the present invention is a spiral pump in which a main shaft 1 is equipped with an impeller 2 in which a plurality of blades 4 are disposed on a main plate 3 and a side plate 5 is provided on the opposite side of the main plate 3 with the blades 4 interposed therebetween. in the pump, a side plate 5 of the main plate 3 and the blade 4 and the impeller 2 of the impeller 2 is formed separately, Ri Na with a gap S can flow is liquid between the facing surfaces of the blade 4 and side plates 5, The gap is 0.2 to 0.4 mm .
[0005]
The centrifugal pump of the invention according to claim 2 is a spiral pump in which a main shaft 1 is equipped with an impeller 2 in which a plurality of blades 4 are disposed on a main plate 3 and a side plate 5 is provided on the opposite side of the main plate 3 across the blades 4. In the pump, the main plate 3 and blade 4 of the impeller 2 and the side plate 5 of the impeller 2 are formed separately, and a gap S through which liquid can flow is provided between the opposing surfaces of the blade 4 and the side plate 5. 5 and the impeller nut 6 are formed integrally on the impeller inlet side via an annular connecting wall 9, and a plurality of oblique hole inducers that penetrate through the annular connecting wall 9 while being inclined with respect to the axial direction of the main shaft 1. 10 is provided at regular intervals in the circumferential direction .
[0006]
According to a third aspect of the present invention, in the spiral pump according to the second aspect, the clearance S between the facing surfaces of the blade 4 and the side plate 5 is 0.2 to 0.4 mm .
[0007]
A centrifugal pump according to a fourth aspect of the present invention is a centrifugal pump in which a main shaft 1 is equipped with an impeller 2 in which a plurality of blades 4 are arranged on a main plate 3 and a side plate 5 is provided on the opposite side of the main plate 3 with the blades 4 interposed therebetween. In the pump, the main plate 3 and blade 4 of the impeller 2 and the side plate 5 of the impeller 2 are formed separately, and a gap S through which liquid can flow is provided between the opposed surfaces of the blade 4 and the side plate 5, The gap S is set to 0.2 to 0.4 mm, and is arranged in the impeller inlet side annular space O between the side plate 5 and the impeller nut 6 at regular intervals in the circumferential direction. A mixed flow inducer 19 is formed between adjacent inclined blade pieces 20 and 20 of the inclined blade pieces 20.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
1 is a partially sectional side view showing an embodiment of a centrifugal pump according to the present invention, FIG. 2 is a front view of an impeller with a casing cover removed from the centrifugal pump shown in FIG. 1, and FIG. It is a XX line expanded sectional view. In these drawings, 1 is the main shaft of the centrifugal pump, and 2 is an impeller attached concentrically to the tip side of the main shaft 1.
[0009]
The impeller 2 sandwiches a main plate 3 fixed to the main shaft 1, a plurality of arcuate curved blades 4 disposed on the front side surface 3a of the main plate 3 at a constant pitch in the circumferential direction, and the blades 4. The main plate 3 and the blade 4 are formed integrally or integrally with the main plate 3, and the side plate 5 is formed separately from the main plate 3, the blade 4, and so on. A gap S through which liquid can flow is formed between the side end face 4a of each blade 4 and the rear side face 5a of the side plate 5. The main shaft 1 is linked to a motor (not shown).
[0010]
In manufacturing the impeller 2, the main plate 3 and the blades 4... May be integrally formed by casting, or the main plate 3 and the blades 4 are formed separately, and the blades 4 are welded to the main plate 3. In any case, the front side surface 3a of the main plate 3 and the surface of each blade 4 and the rear side surface 5a of the side plate 5 may be subjected to electrolytic polishing in addition to buff polishing. Provide sufficient surface finishing. The polishing process in this case is easy to polish because the processed surfaces of the main plate 3 and the blades 4 are open on the front side, and the finished surface roughness can be made sufficiently good.
[0011]
In addition, the gap S through which the liquid can flow is formed between the facing surfaces 4a and 5a of each blade 4 and the side plate 5 as described above, because the side end surface 4a of each blade 4 and the rear side surface 5a of the side plate 5 are formed. If they are brought into contact with each other, the minute gaps between the facing surfaces 4a and 5a are clogged with liquid soot and dust, which is unsanitary. This is because by providing a gap positively between 4a and 5a, that is, by providing a gap S through which the liquid can flow between the facing surfaces 4a and 5a, liquid soot and dust do not clog. The gap S is preferably 0.2 to 0.4 mm, more preferably about 0.3 mm.
[0012]
The main plate 3 of the impeller 2 has a hub 3o that is fitted to the fitted shaft portion 1a of the main shaft 1 and fixed by a key (not shown). The side plate 5 of the impeller 2 is formed integrally with an impeller nut 6 that is screwed into the tip screw portion 1 b of the main shaft 1. A cylindrical portion 8 for fitting a central cylindrical portion 13 of a casing cover 11b, which will be described later, with a slight gap is integrally projected forward at the base end portion of the side plate 5, and the side plate 5 and the impeller are provided on the inlet side of the impeller 2. As shown in FIGS. 1 and 2, the annular connecting wall portion 9 that integrally connects the nut 6 has inclined hole inducers 10 that are inclined with respect to the axial direction of the main shaft 1 and are spaced at regular intervals in the circumferential direction. A plurality are provided.
[0013]
In FIG. 1, a casing 11 surrounds the impeller 2 portion of the pump. A casing body 11 a attached to the casing mounting frame 12 and a casing cover detachably attached to the casing body 11 a on the front side of the impeller 2 by a screw tool 14. 11b. The screw tool 14 is formed by attaching a handle 14b to a screw rod 14a. A plurality of screw holes 21 are provided on the casing body 11a side, and a screw hole insertion hole 22 is provided on the casing cover 11b side at a position corresponding to the screw hole 21. Therefore, in order to attach the casing cover 11b to the casing body 11a, the screw holes 21 of the casing body 11a and the screw hole insertion holes 22 of the casing cover 11b are aligned with each other. The screw rod 14a of the tool 14 may be screwed in. Reference numeral 15 denotes a spiral chamber formed on the outer peripheral side of the casing 11, and 16 denotes a discharge port at the outlet of the spiral chamber 15. Reference numeral 17 denotes a shaft sealing portion, and 18 denotes a balance hole.
[0014]
Further, the casing cover 11b is provided with a central cylindrical portion 13, and the central cylindrical portion 13 is fitted into the cylindrical portion 8 protruding from the base end portion of the side plate 5 with a slight gap, so that the central cylindrical portion is provided. The inside of 13 forms the inlet 7 of the pump. Note that a plurality of annular grooves 8 a are provided on the outer peripheral surface of the cylindrical portion 8 on the side plate 5 side, and between the inner peripheral surface of the front casing 11 c side cylindrical portion 13 and the outer peripheral surface of the side plate 5 side cylindrical portion 8. The labyrinth effect (sealing seal effect) is exhibited.
[0015]
In the centrifugal pump configured as described above, when the main shaft 1 is driven and the impeller 2 is rotated in the counterclockwise direction indicated by the arrow H in FIG. 2, the liquid is supplied from the suction port 7 of the pump to the impeller 2. The air is sucked between the blades 4 and 4 inside the impeller 2 corresponding to each of the oblique hole inducers 10 through the plurality of oblique hole inducers 10 at the inlet, and flows radially outward between the blades 4 and 4. Energy is obtained and the pressure head is raised by the centrifugal action while passing through the spiral chamber 15.
[0016]
In this case, since the liquid sucked into the impeller 2 from the suction port 7 passes through the oblique hole inducer 10, the effective suction head (NPSH) is reduced, the liquid suction characteristic is improved, and the pumping capacity is increased. be able to.
[0017]
In particular, in this centrifugal pump, the main plate 3 and blades 4 of the impeller 2 and the side plate 5 of the impeller 2 are formed separately, so that when the impeller 2 is manufactured, the main plate 3 and the blades 4 and If the side plates 5 are separated from each other, these finished surfaces can be opened, so that finishing by polishing is easy and the finished surface roughness is sufficiently good. It can be. In particular, in the electrolytic polishing operation, the arrangement of the electrodes becomes easy and the operation is easy, and the polishing operation can be performed effectively. Therefore, when the pump is used, various liquid soot and dust do not remain on the inner surface of the impeller 2, which is extremely hygienic.
[0018]
Further, by providing a gap S through which the liquid can flow between the opposed surfaces 4a and 5a of the impeller 2 blades 4 and the side plates 5, the gap S is not clogged with liquid soot and dust. From the point of view, the inside of the impeller 2 can be always sanitized, and is optimal as a sanitary centrifugal pump used for pumping various liquids in the food industry and the pharmaceutical industry.
[0019]
4 is a partially sectional side view showing another embodiment of the centrifugal pump according to the present invention, and FIG. 5 is a front view showing the impeller of the centrifugal pump of FIG. In the spiral pump shown in FIGS. 1 and 2, the inclined hole inducer 10 is provided at the inlet of the impeller 2. In the spiral pump shown in FIGS. 4 and 5, instead of the inclined hole inducer 10, the inlet side of the impeller 2 is provided. The side flow plate 5 and the impeller nut 6 are formed separately from each other.
[0020]
That is, in the centrifugal pump of this embodiment, a plurality of inclined blade pieces 20 are arranged at regular intervals in the circumferential direction in the annular space O formed on the inlet side of the impeller 2 between the side plate 5 and the impeller nut 6. In the state where each inclined blade piece 20 is appropriately inclined with respect to the axial direction of the main shaft 1, the inclined blade pieces 20 are fixed to the side plate 5 and the impeller nut 6 by welding, for example, in the circumferential direction. A mixed flow inducer 19 is formed between adjacent inclined blade pieces 20 and 20.
[0021]
In this way, the diagonal flow between the adjacent inclined blade pieces 20, 20 of the plurality of inclined blade pieces 20 arranged at regular intervals in the circumferential direction O in the impeller inlet-side annular space O between the side plate 5 and the impeller nut 6. By forming the inducer 19, the liquid suction characteristic at the inlet of the impeller 2 can be improved, and the pumping capacity can be further improved.
[0022]
In forming this mixed flow inducer 19, the side plate 5, the impeller nut 6 and the inclined blade piece 20 are formed separately, and the inclined blade piece 20 is welded to the side plate 5 and the impeller nut 6. However, the side plate 5, the impeller nut 6 and the inclined blade piece 20 may be integrally formed by casting or the like.
[0023]
【The invention's effect】
According to the centrifugal pump of the invention according to claim 1, the main plate and blades of the impeller and the side plate of the impeller are formed separately, so that the main plate, the blades, and the side plate are separated when the impeller is manufactured. If this is done, finishing of these members by buffing, electrolytic polishing, or the like becomes easy, and the finished surface roughness of the impeller inner surface can be made sufficiently good. Therefore, when the pump is used, various types of liquid soot and dust do not remain on the inner surface of the impeller, which is extremely hygienic.
[0024]
In addition, since a gap through which the liquid can flow is provided between the opposed surfaces of the impeller blades and the side plate, liquid gaps and dust are not clogged in this gap. It can be hygienic and is optimal as a sanitary centrifugal pump used for the pumping of various liquids in the food and pharmaceutical industries. Further, 0.2 to 0.4 mm is effective as the gap between the facing surfaces of the blade and the side plate.
[0025]
According to the centrifugal pump of the invention of claim 2, in addition to the effect of the invention of claim 1, the side plate and the impeller nut are integrally formed through the annular connecting wall portion on the impeller inlet side, Since a plurality of slant hole inducers that penetrate through the connecting wall in an inclined manner with respect to the axial direction of the main shaft are provided at regular intervals in the circumferential direction, the liquid sucked into the impeller from the pump suction port has a slant hole inducer. By passing, the effective suction head is reduced, the liquid suction characteristics are improved, and the pumping capacity can be increased.
[0026]
Further, as in the spiral pump of the invention according to claim 3, 0.2 to 0.4 mm is effective as the gap between the opposed surfaces of the blade and the side plate of the spiral pump of the invention according to claim 2.
[0027]
According to the centrifugal pump of the invention of claim 4, in addition to the effect of the invention of claim 1 , the centrifugal pump is arranged in the annular space on the impeller inlet side between the side plate and the impeller nut at regular intervals in the circumferential direction. Since a mixed flow inducer is formed between adjacent inclined blade pieces of each of the inclined blade pieces that are inclined with respect to the axial direction of the main shaft, the liquid suction characteristics at the impeller inlet are improved, and the pump capacity is improved. This can be further improved.
[Brief description of the drawings]
FIG. 1 is a partial sectional side view showing an embodiment of a centrifugal pump according to the present invention.
FIG. 2 is a front view of the impeller with a casing cover removed from the centrifugal pump shown in FIG.
FIG. 3 is an enlarged cross-sectional view taken along line XX of FIG.
FIG. 4 is a partial sectional side view showing another embodiment of the centrifugal pump according to the present invention.
FIG. 5 is a front view showing an impeller of the centrifugal pump of FIG. 4;
[Explanation of symbols]
1 Main shaft 2 Impeller 3 Main plate 4 Blade 5 Side plate 6 Impeller nut 10 Oblique hole inducer 19 Diagonal flow inducer 20 Inclined blade piece

Claims (4)

In a centrifugal pump equipped with a main shaft having an impeller having a plurality of blades arranged on the main plate and a side plate provided on the opposite side of the main plate across the blades, the main plate of the impeller and the blade and the side plate of the impeller are formed separately. , Ri Na provided can flow liquid gap between opposing surfaces of the blade and the side plate, centrifugal pump characterized by comprising the said gap as a 0.2 to 0.4 mm. In a centrifugal pump equipped with a main shaft having an impeller having a plurality of blades arranged on the main plate and a side plate provided on the opposite side of the main plate across the blades, the main plate of the impeller and the blade and the side plate of the impeller are formed separately. The gap between the opposing surfaces of the blade and the side plate is provided with a gap through which liquid can flow, and the side plate and the impeller nut are integrally formed on the impeller inlet side via the annular connecting wall portion. A spiral pump comprising a plurality of oblique hole inducers that are inclined and penetrated with respect to the axial direction of the main shaft at regular intervals in the circumferential direction. The centrifugal pump according to claim 2, wherein a gap between opposed surfaces of the blade and the side plate is 0.2 to 0.4 mm. In a centrifugal pump equipped with a main shaft having an impeller having a plurality of blades arranged on the main plate and a side plate provided on the opposite side of the main plate across the blades, the main plate of the impeller and the blade and the side plate of the impeller are formed separately. In addition, a gap through which liquid can flow is provided between the opposed surfaces of the blade and the side plate, and the gap is set to 0.2 to 0.4 mm, and the impeller inlet side annular space portion between the side plate and the impeller nut A spiral pump characterized in that a mixed flow inducer is formed between adjacent inclined blade pieces of a plurality of inclined blade pieces that are arranged at regular intervals in the circumferential direction and are inclined with respect to the axial direction of the main shaft. .

Images