JPH0455277Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rotation prevention structure for a casing of a multi-stage centrifugal pump made of a steel plate, and in particular, a plurality of adjacent intermediate casings fitted into an outer casing, The present invention relates to a three-piece rotation prevention structure of a guide vane sandwiched between these adjacent intermediate casings.

[Problems to be solved by conventional techniques and ideas]

In multi-stage centrifugal pumps made of steel plates, the intermediate casing, which is manufactured by pressing the steel plate, has a structure that makes it difficult to prevent rotation due to the manufacturing method. In many cases, parts were welded to the circumferential surface of the intermediate casing to prevent rotation, or rotation was often prevented only by the friction caused by the tightening force of the through bolt in round-cut types.

However, due to the friction mentioned above,
It is necessary to keep the tightening force constantly applied, and on the other hand, using separate parts increases the number of man-hours, and there is a problem that these separate parts protrude into the flow path and impede smooth flow. The point was hot.

The present invention is capable of attaching each member of the guide vane sandwiched between the two adjacent intermediate casings and the two intermediate casings without attaching separate parts by welding or fastening with through bolts as described above. It is an object of the present invention to provide pump casings that can simultaneously prevent rotation between the intermediate casings of each stage and the rotation of a differential user by engaging with each other.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a convex part that protrudes inward on the peripheral surface of the intermediate casing made of steel plate, and extends the convex part in the radial direction of the partition plate fixed to the front surface of the next stage intermediate casing. A notch corresponding to the convex portion is provided on one side, and a notch corresponding to the convex portion is provided at the circumferential end of the convex portion, and a differential user outlet portion of the guide vane held between the intermediate casing of the previous stage and the intermediate casing of the next stage is provided. It is characterized in that one end of the guide vane is brought into contact with the other to prevent rotation of the front intermediate casing, the rear intermediate casing, and the guide vane held by these two adjacent intermediate casings.

[Effect]

Since the present invention is constructed as described above, when the pump casing is assembled, the two adjacent intermediate casings of the previous stage and the next stage are attached to the convex part that protrudes inwardly on the peripheral surface of the intermediate casing of the previous stage. Since the notches on the outer part of the partition plate fixed to the front surface of the next-stage intermediate casing are engaged, they are locked to each other in the circumferential direction (rotation direction), and
The guide vane held between the two adjacent intermediate casings has one end of the differential user outlet portion of the guide vane in contact with the circumferential end of the convex portion of the intermediate casing peripheral surface. The guide vane is also secured to the intermediate casing in the rotational circumferential direction.

In this way, the rotational circumferential direction of the three adjacent intermediate casings, that is, the intermediate casings of the previous stage and the next stage, and the guide vanes held between these two intermediate casings is prevented from rotating. In the same manner, each adjacent intermediate casing and guide vane are sequentially prevented from rotating relative to each other in the rotational circumferential direction. By fixing the final intermediate casing to the outer casing side by appropriate means, A casing and guide vanes can be secured within the outer casing.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of essential parts of a multistage centrifugal pump showing an embodiment of the present invention.

In the figure, a plurality of press-formed pieces are formed in an outer casing 1 made of a steel plate, each consisting of a side surface (end surface) portion 2a in the direction perpendicular to the axis, and a circumferential surface portion 2b integrally formed radially outward of the side surface portion 2a. The intermediate casings 2 are sequentially inserted without any gaps in the axial direction, and the peripheral surface portions 2b of these intermediate casings 2 are integrally formed with convex portions 3 that protrude inward.
Further, a partition plate 4 is fixed to the front surface of the side surface portion 2a by spot welding 4a so as to be located inside the intermediate casing on the front stage side. As shown in FIG.
A notch 4b that corresponds to and engages with is provided.

On the other hand, the guide vane 5 is sandwiched between the intermediate casings 2, 2 of the previous stage and the next stage, which are mounted adjacent to each other as described above. As shown in FIGS. 2a, b, and c, the guide vane 5 includes a diffuser portion 51 that has vanes 51a that are inclined in the rotational direction of the impeller 6 on the outside of the outlet portion of the impeller 6, and that recovers pressure. and a return passage 52 which communicates with the diff user part 51 and has vanes 52a provided on the back side (next stage side) of the guide vane side wall 5a and guides the flow in the radial direction.

Opening/turning portions or notches 5b (X-marked portions in the figure) that communicate the differential user portion 51 and the return passage 52 are formed at equal intervals on the outer periphery of the side wall 5a (FIG. 2 a, c). , the convex portion 3 of the intermediate casing peripheral surface portion 2b is engaged with the notch portion 5b. Further, one end 51b of the outlet portion of the differential user portion 51 is adapted to come into contact with the circumferential end portion of the convex portion 3 of the intermediate casing peripheral surface portion 2b.

A similar convex portion 3 is also provided on the final stage intermediate casing 2, and the convex portion 3 is attached to the inner peripheral portion of a casing cover 7 which is fixed to the motor etc. with bolts together with the outer casing 1. It is locked in the rotational direction by a protruding member (spigot plate) 8 which protrudes in the axial direction and has a forked tip portion so as to engage with the forked portion. In the figure, 9 is a liner ring attached to the partition plate 4, 10 is a pump suction port, and 11 is a pump discharge port.

Since it is configured as described above, the two adjacent intermediate casings 2, 2 of the previous stage and the next stage are fixed to the convex part 3 of the peripheral surface part 2a of the previous stage intermediate casing and to the front surface of the next stage intermediate casing. The notches 4b of the partition plate 4 are locked to prevent each other from rotating, and the guide vane 5 is connected to the differential user part 5.
Since one end 51b of the outlet portion 1 is in contact with the circumferential end portion of the convex portion 3, rotation of the three intermediate casings and the differential user can be easily prevented from rotating.

Therefore, the sealing work between the intermediate casing stages becomes easy, and as in this embodiment, only a so-called metal touch, which is a direct metal contact, is required without a sealing member, and the tightening force is reduced by the difference in internal pressure between stages of the pump during operation. At the same time, even in the early stages of operation when sufficient internal pressure is not generated, there is no need to tighten to prevent rotation, and the structure has a structure in which strength and rigidity only need to be considered based on the force due to operating pressure.

[Effect of idea]

As explained above, according to the present invention, the inwardly protruding convex portion provided on the peripheral surface of the intermediate casing is engaged with the notch of the partition plate fixed to the front surface of the next stage intermediate casing. In addition, one end of the differential user outlet portion of the guide vane held between the intermediate casings of the previous stage and the next stage is brought into contact with the circumferential end of the convex part of the intermediate casing. It is possible to simultaneously prevent the casings from rotating and the differential user from rotating. Therefore, the following effects are achieved.

(i) Easier sealing between intermediate casing stages;
During operation, it is sealed by the clamping force generated by the pressure difference between stages, and there is no need to tighten it to prevent rotation even in the early stages of operation.For strength and rigidity, only the force due to operating pressure is considered. Become.

(ii) Since each part is securely prevented from rotating, accidents caused by temperature, loosening of screws, etc. can be prevented.

(iii) When preventing rotation of the differential user part, there is no need to provide a pin-like protrusion as was conventionally used, and in this invention, since the outermost periphery is prevented from rotating, it has sufficient strength. It does not break like conventional pins.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of essential parts of a multistage centrifugal pump showing an embodiment of the present invention, Fig. 2a is a side view of the open side (previous stage side) of the guide vane, Fig. 2b is a circumferential view, and Fig. 2c is
is a side view of the non-opening side (next stage side), Figure 3 a and b
FIG. 2 is a side view and a cross-sectional view of a main part of an intermediate casing to which a partition plate is fixed. 1...Inner casing, 2...Intermediate casing,
2b...Surrounding part, 3...Convex part, 4...Partition plate, 4
b...notch, 5...guide vane, 51...diff user section, 51a...blade, 51b...one end of outlet section, 52...return passage, 6...impeller, 7...
...Casing cover.

Claims (1)

[Scope of utility model registration request] In a multi-stage centrifugal pump made of steel plates, an inwardly protruding convex portion is provided on the radially outer peripheral surface of an intermediate casing made of steel plates, and a convex portion protrudes inwardly in the radial direction of a partition plate fixed to the front surface of the next stage intermediate casing. In the outer part,
A notch corresponding to the convex portion is provided, and one end of the differential user outlet portion of the guide vane sandwiched between the previous intermediate casing and the next intermediate casing is brought into contact with the circumferential end of the convex portion. A rotation prevention structure for a pump casing, characterized in that the rotation is prevented by three parts: a front intermediate casing, a rear intermediate casing, and a guide vane sandwiched between these intermediate casings.