CN1101526C - Pump shell structure of multi-stage sheet-metal working pump and its manufacturing method - Google Patents

Abstract

The present invention relates to a pump casing structure for multi-stage sheet metal pumps and a manufacture method thereof. The pump casing is formed by combining an external casing body and internal casing body, wherein the external casing body is formed integrally and comprises a front side casing surface, a ladder-shaped ladder positioning surface, an external side casing surface and a positioning end surface, the internal casing body is fixed in the external casing body and comprises an internal end surface, an internal side casing surface and a ladder-shaped positioning end part, containing space is formed between the positioning end part of the internal casing body and the external side casing surface of the external casing body, and a leakage-stopping ring is plugged in the space. When a plurality of pump casings are combined in a series connection mode, the positioning end surface of an external casing body of a previous casing can just be abutted on the ladder positioning surface of an external shell body of the next pump casing.

Description

Pump shell structure of multi-stage sheet-metal working pump and manufacture method thereof

The present invention relates to a kind of pump shell structure and manufacture method thereof of multi-stage sheet-metal working pump, refer to a kind of panel beating system multistage pump that is applicable to submersible pump especially.

Mostly present multistage centrifugal pump (for example submersible pump) is a plurality of housing groups that are provided with the pumping runner are connected in series in regular turn with rotary blade and is combined on the running shaft, make it carry out relative rotary motion by the running shaft impeller, reach the purpose that the fluid compression pump with enclosure interior send in enclosure interior.The multistage pumping shell construction that tradition is made with die casting causes shortcomings such as pumping usefulness is lower because comparatively benzene is heavy, material behavior is relatively poor, be difficult for forming runner, is therefore replaced by the shell construction of panel beating system gradually now.

For the panel beating system housing of multi-stage centrifugal pumping, the main consideration in its design includes: make assembly cost, pumping usefulness and diversion Design, compressive strength and leakproof or the like.Yet traditional panel beating system multistage pump rarely has can have above-mentioned characteristics person simultaneously concurrently.For example, European patent application numbers 81110541.0 just discloses a known pump shell structure that the formula sheet-metal working pump is arranged more, as shown in Figure 1, it overlaps wherein one-level 2 (or the title one-level: stage), be equipped with impeller 3 (impeller) and guide-leaf plate 20 elements such as (baffles) in the housing 11 of this level 2 of forming multi-stage sheet-metal working pump by housing 11 (casing), the cooperation demarcation strip 12 (partition member) that punching press one panel beating material forms given shape.The characteristic of this application is to be provided with a recessed pars convoluta 19 (curved portion) by its housing 11, and it can be for the winding of front and back stages 2 housings 11, in 11 windings place of front and back two housings and be provided with seal ring 14 (sealring).Yet, because the housing 11 of European patent application number 81110541.0 cases has the structure that is overlapped and located by circular-arc recessed pars convoluta 19, its recessed pars convoluta 19 is circular-arc curved surfaces, its size goes up original just more inaccurate with the location, add several grades of housings 11 serial connection be assembled in one go up after, must be towards " axially " locking of exerting pressure, this moment this circular-arc recessed pars convoluta 19 the location become the ten minutes inaccuracy, it is difficult in control of axial deflection, easily causes to leak or the rub consequence of guide-leaf plate 20 of impeller 3.And, this housing 11 terminal 111 and next group housing lap-joint only are in contact with one another face for inside and outside two parallel-plates, though the setting of seal ring 14 is arranged therebetween, yet when the housing 11 of sheet-metal working pump was subjected to bigger pressure or housing 11 vibrations take place, these housing 11 ends 111 still outwards opened easily and leakage phenomenon take place.In addition, owing to there is no good water conservancy diversion curved surface setting between its housing 11 inner side surfaces and the impeller 3, cause near fluid generation sinuous flow and reduce pumping usefulness housing 11 inner side surface front ends 112 easily in the pumping process.Thereby have: axially locating is not good, easy leaks, with shortcomings such as pumping usefulness is lower.

Figure 2 shows that U.S. Patent number US.Pat.No.5,234,317 disclosed sheet-metal working pumps, it is pump case 21 structures of being processed into by oil pressure.Though, U. S. Patent the 5th, 234, thereby No. 317 produce more closely with next group pump case 21 by pump case 21 ends 211 being designed to the U-shaped structure that overlap joint cooperates, yet, because this pump case 21 terminal 211 is relative less with the surface of contact (sealing surface) of next group pump case front end, so when being subjected to bigger pumping pressure or pump case 21 generation vibrations, these pump case 21 ends 211 still have the phenomenon of outwards opening and leaking.And the structure of its pump case 21 can't form with simple punching press, and must be by oil pressure (hydraulic pressure) machine shaping, and its cost of production is corresponding to be increased.In addition, U. S. Patent the 5th, 23 near No. 317 the pump case 21 inner side surface front ends 212 and still do not have good water conservancy diversion curved surface setting between the impeller, still easily causes the generation of sinuous flow and reduces pumping usefulness.Therefore, it still has: cost of production is higher, high pressure or shortcoming such as when vibrations easily leaks and pumping usefulness is lower.

U. S. Patent the 5th, 234, No. 317 disclosed sheet-metal working pump shell structure (not shown), the terminal structure with next group pump case lap-joint of its pump case is to bend to a S shape, can have better structural strength and avoid Zhang Zaocheng leakage outside the pump case end, yet its complicated structure all makes the pump case manufacture cost further raise on the contrary.And near the end and the space between the impeller does not still have good water conservancy diversion curved surface setting in face of the inside pump casing of this case, so still have the limited disappearance of pumping usefulness.

As shown in Figure 3, for another kind at present on the market as seen but not application obtain the known sheet-metal working pump shell structure of patent, be provided with the water conservancy diversion curved surface in its pump case, thereby can have preferable pumping usefulness with respect to aforesaid prior art.These known panel beating pump case 4 structures comprise: a front casing body 41, a rear casing body 42, one preceding inner housing 43, a back inner housing 44, a diffuser 45, an impeller housing 46, a front seal ring 47 and an impeller (not shown).End is provided with a front side shell face 413 and the stepped radial location face 411,412 that axially reaches before front casing body 41.42 of rear casing bodies are provided with and the axial and radial location end face 421,422 that should axially reach radial location face 411,412 corresponding matching.End is provided with end 441, a location after the inner housing 44 of back.When the assembling of single pump case 4 structures, inner housing 43 before earlier guide vane wheel 45 welding being positioned, and then front casing body 41, rear casing body 42, preceding inner housing 43 and 44 combinations of back inner housing (because will not cause inner housing 43,44 to be put to advance in the frame 41,42) if so do not assemble, enclose around welding one at soldering point 48 places in the mode of " boxing " more afterwards, thereby be assembled into pump case 4 structures.When a plurality of pump case 4 serial connections are assembled, a back pump case 4 side shell face 413 before just can be replaced in the end, location 441 of previous pump case 4, and the axial and radial location end face 421,422 of previous pump case 4 just can be replaced the radial location face 411,412 that axially reaches of a back pump case 4, except that carrying out the location of a plurality of pump cases 4 location end face 421,422 and the effect that also has the sealing leak-stopping cooperating of locating face 411,412 concurrently.And the arcuation configuration of forward and backward inner housing 43,44 also can provide good water conservancy diversion curved surface effect, to improve pumping usefulness.

Only, prior art as shown in Figure 3 still has some shortcomings, comprising:

(1) number of elements is numerous.Existing pump case 4 structures as shown in Figure 3 have the element more than totally eight such as forward and backward frame 41,42, forward and backward inner housing 43,44, diffuser 45, impeller housing 46, front seal ring 47 and impeller altogether, it is complicated time-consuming not only to assemble finder, and the quantity that element is made processing mold also heightens relatively, and its cost of production increases much relatively.And impeller housing 46 all need additionally be provided with the also shape increase mutually of its cost with front seal ring 47.

(2) need the processing of secondary precision turning.Because the sealing effect of pump case 4 is to reach with cooperating of locating face 411,412 with location end face 421,422, therefore locating precision that no matter end face 421,422 and locating face 411,412 assemble in size, planeness and collocation mutually all requires very high, general punch process to reach to seal the required precision of leak-stopping.So, the mode that existing pump case 4 shown in Figure 3 needs with the processing of secondary precision turning, position the processing of end face 421,422 and locating face 411,412, not only turning cost of processing higher (with respect to punch process), and turning processing also will cause the thickness attenuation more of panel beating pump case (thickness is just not thick originally), and lose the structural strength of pump case 4.

(3) boxing cost height and dimensional accuracy is low.Pump case 4 is a circle at soldering point 48 places (boxing), not only the cost of boxing is several times of general (spot welding) cost even more than ten times, and boxing more will cause, and the aesthetic property of pump case outward appearance reduces, the size distortion precision reduces (will be the protuberance state in boxing place), the assembling positioning difficulty increases, and the material behavior of boxing place will go to pot, and intensity control is difficult for.And, the secondary turning processing of preceding art position end face 421,422 and locating face 411,412 needs carry out after boxing, the size distortion that causes because of boxing needs remedy with turning processing, will cause the turning part more and pump case thickness is thinner, sometimes even the situation that pump case breaks can take place.

Take a broad view of above-mentioned all existing sheet-metal working pump shell structures, all can't satisfy simultaneously and make assembly cost, pumping usefulness and Considerations such as diversion Design, compressive strength and leakproof, so still have the leeway of further improvement.

Main purpose of the present invention provides a kind of shell structure and manufacture method thereof of multi-stage sheet-metal working pump, can be with advantage such as make that assembly cost is lower, compressive strength is sufficient and leak preventing effect is better.

For achieving the above object, the present invention proposes a kind of pump shell structure of multi-stage sheet-metal working pump, wherein this multi-stage sheet-metal working pump is to be connected in series in regular turn to be combined on the running shaft by a plurality of pump case groups to constitute, and this pump case group comprises a pump case, an impeller, reaches a diffuser.This pump case group is combined into by a frame and an inner housing.Frame is one-body molded and includes a front side shell face, a stepped ladder locating face, an outer shell face and a location end face.Inner housing is to be fixed in the frame and to include an interior edge face, an inboard shell face and a stepped end, location, makes to be formed with a containing space that can supply to plug a seal ring between the outer shell face of the end, location of this inner housing and frame.When a plurality of pump case serial connections are made up, the location end face of the frame of previous pump case just can be replaced the ladder locating face of the frame of a back pump case, and the front side shell face of the frame of a back pump case group just can be replaced in the end, location of the inner housing of previous pump case group, thereby the pump case group in running shaft axially on the location, and make this seal ring oppressed in the containing space of this sealing.Wherein, the front side end of the front side shell face of this frame and the interior edge face of this inner housing, all bend to the direction that is parallel to running shaft and extend, and it has an appropriate gap between the two, the position of this appropriate gap and size just corresponding matching in the impeller eye of impeller, and with the effect of impeller ring.

The manufacture method of the pump shell structure of this multi-stage sheet-metal working pump, at first be by one sheet metal being carried out once above processing with impact style, and form the front side shell face of this frame, stepped ladder locating face and outer shell face portion, but the location end face does not form in this step as yet; And, respectively other two sheet metals are carried out once above processing by impact style, with front half part and the latter half part that forms an inner housing respectively, this front half part comprises the interior edge face part of inner housing and the inboard shell face portion of only about half of length at least, and this latter half part comprises side shell face portion and end, location within the only about half of length of inner housing at least.Then, the latter half part of front half part, diffuser and the inner housing of inner housing is inserted in regular turn and is weldingly fixed in the frame.With impact style the outer shell surface rear end of frame is partly processed again at last, made it form this positioning end face portion.

The pump shell structure of multi-stage sheet-metal working pump of the present invention is comparatively simple, can reduce assembly cost and difficulty, and has the pump shell structure of good assembling sealing and fluid pumping usefulness.

Fig. 1 is the generalized section of the pump shell structure of existing multi-stage sheet-metal working pump;

Fig. 2 is the generalized section of the pump shell structure of another existing multi-stage sheet-metal working pump;

Figure 3 shows that the application identical inventor a kind of sheet-metal working pump shell structure of once developing;

Fig. 4 is the generalized section of a preferred embodiment of two of single pump case group of the present invention/part;

Fig. 5 is the generalized section of a preferred embodiment of a plurality of pump case group serial connection of the present invention combination;

Fig. 6 is near another embodiment of the structure of location end face 615a of sheet-metal working pump shell structure of the present invention.

See also Fig. 4 and Fig. 5, be a preferred embodiment of the pump shell structure of multi-stage sheet-metal working pump of the present invention.This multi-stage sheet-metal working pump is to be connected in series in regular turn to be combined on the running shaft 5 by a plurality of pump case groups 6 to constitute, and this pump case group 6 comprises a pump case, an impeller 7, and element such as a diffuser 8.Because aforesaid running shaft 5, impeller 7, and the detailed structure of diffuser 8, and this detailed marriage relation of pump case, impeller 7 and diffuser 8 and running shaft 5, therefore be not feature of the present invention place, in the following description, will do not given unnecessary details, close chat earlier bright.

Characteristics of the present invention mainly are the structure and the manufacture method thereof of this pump case, and as shown in Figure 4, this figure is the generalized section of two of single pump case group 6/part.Fig. 5 then is connected in series the generalized section (Lower Half of Fig. 5 discloses the part marriage relation that has between pump case, an impeller 7 and a diffuser 8 and the running shaft 5) of combinations for a plurality of pump case groups 6.

This pump shell structure comprises a frame 61, an inner housing 62 and a seal ring 9.

This frame 61 is by the processing more than carrying out once with impact style to a sheet metal (for example stainless steel), and the ring structure that is formed in one.Make ring structure frame 61 extend following at least part in regular turn: this front side end 611 of extending a suitable distance along the direction that is in substantially parallel relationship to running shaft 5 from one front side end 611 (being the left-hand end of Fig. 4) beginning, one along rough direction perpendicular to running shaft 5 outwardly (promptly, the direction that radius increases) the front side shell face 612 that extends, one by the rough stepped outward extending ladder locating face 613 that is of these front side shell face 612 outer periphery, one along the rough outer shell face 614 that is parallel to the direction extension of running shaft 5, and one be positioned at the terminal and location end face 615 that extend towards running shaft 5 (that is, radius reduce direction) of this outer shell face 614.And the interior angle between the location end face 615 of frame and this outer shell face 614 is preferable slightly to equal an angle of 90 degrees, but it also can be slightly larger than an angle of 90 degrees (as shown in Figure 6).In addition, this stepped ladder locating face 613 in ladder corner location part to be designed to be slightly vertical angle but corner slightly indent be preferable (can have stamping process now reaches), in fact, because the angle of this stage shape ladder locating face 613 is roughly to cooperate the slanted angle of locating end face 615 designed, so it also might be to be slightly less than an angle of 90 degrees.

This inner housing 62 is set at and is fixed into one in the frame 61 and with it, and this diffuser 8 is placed in the inner housing 62.Inner housing 62 is by extending in regular turn near 621 beginnings of a front side end of this front side shell face 612, at least comprise: this front side end 621 of extending a suitable distance along the rough direction that is parallel to running shaft 5, one along the rough interior edge face 622 that extends outwardly perpendicular to the direction of running shaft 5, one with running shaft 5 almost parallels and be fixed in the inboard shell face 623 of outer shell face 614, and one roughly be a stepped end, location 624 that extends internally by inboard shell face 623 ends, be formed with a containing space 625 between the end, location 624 of this inner housing 62 and the outer shell face 614 of frame 61, for ccontaining this seal ring 9, be fixed in the inner housing 62 as for 8 of this diffusers within end face 622 positions.And, the part that between between end face 622 within the inner housing 62 and the inboard shell face 623 and inboard shell face 623 and end 624, location, links to each other, all be designed to arcuation water conservancy diversion curved surface 626,627, can make fluid be difficult for producing the sinuous flow phenomenon to diffuser 8 by smooth and easy guiding from impeller 7 pumpings.

As shown in Figure 5, when a plurality of pump case groups 6 being connected in series in regular turn combination, the location end face 615 of the frame 61 of previous (left side of Fig. 5) pump case group 6 just can be replaced the ladder locating face 613 of the frame 61 of back one (right side of Fig. 5) pump case group 6, and the front side shell face 612 of the frame 61 of a back pump case group 6 just can be replaced in the end, location 624 of the inner housing 62 of previous pump case group 6, thereby form pump case group 6 in running shaft 5 axially on the location, and make this containing space 625 become an enclosed space, and seal ring 9 also can be therefore oppressed in the containing space 625 of this sealing to reach the effect of leak-stopping.And, since the location end face 615 of this frame 61 be to replace on the ladder locating face 613 that is contacted with a back frame 61 in a mode that tilts, therefore, even when this pump shell structure bears big pumping pressure, the location end face 615 of this frame 61 also is difficult for taking place the outer leakage situation of opening.In addition, the front side end 611 of this frame 61 and the front side end 621 of this inner housing 62, all be that bending (please notes to the direction extension that is parallel to running shaft 5, wherein this front side end 611 except as can be as shown in Figure 4 towards extend in the left side, also can be the right direction extension in figure), and it has an appropriate gap between the two, and the position of this appropriate gap and size just corresponding matching thereby can be with the effect of impeller ring in the impeller inlet opening 71 of previous impeller 7.

Among the embodiment of the following stated, because most of element is the same as or similar to previous embodiment, therefore, identical or similar elements will give identical title and numbering and will not give unnecessary details, and just increase by English a numbering as a means of difference after former numbering in addition.

Figure 6 shows that near another embodiment of the structure of location end face 615a of sheet-metal working pump shell structure of the present invention.The location end face 615a of this frame 61a can be designed to be one be slightly larger than 90 the degree angles angles, when it is fastened in the ladder locating face 613a of a back pump case, can one similar " chimeric " mode be resisted against on the ladder locating face 613a, cooperate the utilization of seal ring 9, can provide better leak-stopping sealing effect (because heal when big when pressure, the location end face 615a that tilts will be more against to ladder locating face 613a), yet this kind design will need the requirement that is processed with degree of precision to location end face 615a.

One preferred embodiment of the manufacture method of the pump shell structure of multi-stage sheet-metal working pump of the present invention can include the following step:

A. with impact style one sheet metal is carried out once above processing, with front side end 611, front side shell face 612, stepped ladder locating face 613 and outer shell face 614 parts that form this frame 61, but location end face 615 does not form in this step as yet;

B1. respectively two sheet metals are carried out once above processing with impact style, with a front half part and a latter half part that forms inner housing 62 respectively, this front half part comprises inboard shell face 623 parts of front side end 621 parts, interior edge face 622 parts and the only about half of length of inner housing 62 at least, and this latter half part comprises inboard shell face 623 parts and the end 624, location of about second half length of inner housing 62 at least;

B2. with the front half part front end of inner housing 62 and the front end of diffuser 8, to insert on the location in the frame 61 by the rear end of frame 61, diffuser 8 is incorporated in the front half part of inner housing 62 in advance in the spot welding mode;

B3. with the latter half part of inner housing 62, end is inserted in the frame 61 and corresponding to this front half part after inserting frame 61 by the rear end of frame 61, and process with welding manner (is preferable with spot welding), inner housing 62 forward and backward half ones are combined into one and are fixed in simultaneously on the inner surface of outer shell face 614 of frame 61;

C. by impact style outer shell face 614 rear end parts of frame 61 being processed makes it form this location end face 615 parts.

Because the pump shell structure of multi-stage sheet-metal working pump of the present invention, its frame 61 is all very simple with the configuration of inner housing 62, thus no matter in make or assembling on all more or less freely relatively and cost is lower.And, because its inner housing 62 is earlier in conjunction with being fixed on after frame 61 inside, latter half of punch process to frame 61 forms this location end face 615 again, so inner housing 62 structures of frame 61 inside can provide a support force and the structural strength of stiffened shell body 61, not only it can not cause the distortion of frame 61 when forming the punch process of location end face 615, and the easier and cost of its punching press design of Clamping Apparatus is reduced, and, when multistage pump uses, also will be because of the increase of pump case intensity, and be difficult for being subjected to high pressure (high pumping pressure) or when vibrations increasing, frame 61 ends (location end face 615 parts) take place outwards to be opened and cause the escape of liquid phenomenon.And, more because the location end face 615 of frame 61 is to replace to lean against on the stepped of another frame 61 and the also corresponding ladder locating face 613, so, when the hydrodynamic pressure of pump case inside is healed when big, this positioning end 615 will be more near on the ladder locating face, so just be the machining accuracy of pump case reduce a little also never as for have influence on its excellent leakage-proof effect (prior art will be if pump case machining accuracy deficiency will have a strong impact on leakage-proof effect) still more the present invention have additional again a seal ring in outside, inner housing 61, in the airtight containing space 625 between 62, therefore have hardly any leakage phenomenon takes place.In addition, there is the water conservancy diversion curved surface 626,627 of arc line type to guide fluid in inner housing 62 and design, thus in the pumping process, be difficult for producing the sinuous flow phenomenon, and can obtain higher relatively pumping usefulness.Therefore, the pump shell structure of multi-stage sheet-metal working pump of the present invention assembly cost is relatively low with making really, pumping usefulness and diversion Design is preferable, compressive strength is sufficient and better or the like the advantage of leak preventing effect, overcome the shortcoming of prior art fully.

Outside this, with respect to communal technique shown in Figure 3, the present invention has more following advantage:

(1) number of elements is less.Only have as Fig. 4 and pump case group 6 structures of the present invention shown in Figure 5: totally five elements (lacking three elements than prior art shown in Figure 3) such as a frame 61, inner housing 62 front and back two-part, diffuser 8 and impeller etc., it is relatively easy not only to assemble finder, and the quantity that element is made processing mold also significantly is reduced by at least four pairs more than the mould, and its cost of production reduces many relatively.And impeller housing and front seal ring all do not need extra setting fully, and cost relatively significantly reduces.

(2) do not need the processing of secondary precision turning.Because the sealing effect of pump case group 6 is with location end face 615 and ladder locating face 613, the cooperation that adds seal ring 9 is in addition reached again, therefore locating end face 613 does not need high in the extreme with ladder locating face 613 mutual precision of arranging in pairs or groups assembling, secondary punching press processing procedure of the present invention enough reaches the required precision of sealing leak-stopping, and cost significantly reduces.

(3) do not need the boxing processing procedure.Because frame 61 of the present invention is single integrated element, so do not need to carry out with boxing the combination of element, only spot welding just can reach required adhesive strength.Not only the cost of spot welding significantly lowers, and the outward appearance of pump case group 6 is kept attractive in appearance, structural strength is also preferable.More because spot welding is difficult for causing pump case group 6 size distortions to influence precision, therefore aforesaid location end face 615 does not need secondary turning processing can keep required precision with ladder locating face 613 yet.And spot welding also is difficult for causing the changer of material behavior.

Certainly, the above utilizes a preferred embodiment to describe the present invention in detail, but not limits the scope of the invention, and know this type of technician and all can understand, suitably do slightly change and adjustment, will not lose main idea of the present invention place, also do not break away from the spirit and scope of the present invention.

Claims (8)

1. the pump shell structure of a multi-stage sheet-metal working pump, this multi-stage sheet-metal working pump is to be connected in series in regular turn to be combined on the running shaft by a plurality of pump case groups and impeller to constitute, each pump case group all comprises a pump case, an impeller at least, reaches a diffuser, and this pump shell structure is characterised in that:

This pump case is fixedly to be made of a frame and the combination of inner housing institute;

This frame has integrated ring structure, and begins to extend following at least part by one of frame end: one is outer shell face and that a stepped outward extending ladder locating face, extends along the rough direction that is parallel to running shaft and is positioned at the terminal and location end face that extend towards running shaft of this outer shell face by these front side shell face outer periphery are rough along the rough front side shell face that extends outwardly perpendicular to the direction of running shaft; And,

This inner housing is to be arranged in the frame and to combine with it to be fixed into one, inner housing comprises by beginning to extend at least near an end of this front side shell face: one along the rough interior edge face that extends outwardly perpendicular to the direction of running shaft, one with the rough parallel and inboard shell face and that is fixed in the outer shell face of running shaft by the rough stepped end, location that extends internally that is of inboard shell face end, make to be formed with a containing space between the outer shell face of the end, location of this inner housing and frame;

When a plurality of pump case groups being connected in series in regular turn combination, the location end face of the frame of previous pump case group just can be replaced the ladder locating face of the frame of a back pump case group, and the front side shell face of the frame of a back pump case group just can be replaced in the end, location of housing within the previous pump case group, with realize the pump case group in running shaft axially on the location, and make this containing space become an enclosed space;

Wherein, the front side end of the front side shell face of this frame and the interior edge face of this inner housing, all bend to the direction that is parallel to running shaft and extend, and it has an appropriate gap between the two, the position of this appropriate gap and size just corresponding matching in the impeller eye of impeller, and with the effect of impeller ring.

2. the pump shell structure of multi-stage sheet-metal working pump as claimed in claim 1, wherein, further include a seal ring, be placed in this containing space, when a plurality of pump case groups being connected in series in regular turn when combination, seal ring can be oppressed in the containing space of this sealing to reach the effect of leak-stopping.

3. the pump shell structure of multi-stage sheet-metal working pump as claimed in claim 1, wherein, the location end face of this frame and the angle of this outer shell face are be substantially equal to an angle of 90 degrees skewed, and this stepped ladder locating face and this location end face part that matches has mutual corresponding structure, make when a plurality of pump case groups are connected in series combination in regular turn, the location end face of previous pump case group just can be replaced mutually with the ladder locating face of a back pump case group and contact, therefore, even when this pump shell structure bore big pumping pressure, the location end face of this frame also was difficult for taking place the outer leakage situation of opening.

4. the pump shell structure of multi-stage sheet-metal working pump as claimed in claim 1, wherein, the part that between between the interior edge face of inner housing and the inboard shell face and inboard shell face and end, location, links to each other, all be designed to arcuation water conservancy diversion curved surface, make fluid be difficult for producing the sinuous flow phenomenon to diffuser by smooth and easy guiding from the impeller pumping.

5. the pump shell structure of multi-stage sheet-metal working pump as claimed in claim 1, wherein the angle of the location end face of this frame and this outer shell face is the skewed of slightly about an angle of 90 degrees, and this stepped ladder locating face and this location end face part that matches has and is the mutual corresponding an angle of 90 degrees structure that is slightly less than, make when a plurality of pump case groups are connected in series combination in regular turn, the location end face of previous pump case group is replaced mutually in an inclination mode with the ladder locating face of a back pump case group and is contacted, therefore, even when this pump shell structure bore big pumping pressure, the location end face of this frame also was difficult for taking place the outer leakage situation of opening.

6. the pump shell structure of multi-stage sheet-metal working pump as claimed in claim 1, wherein, this diffuser is placed in the inner housing and is fixed in the interior edge face position of inner housing.

7. the manufacture method of the pump shell structure of a multi-stage sheet-metal working pump as claimed in claim 1 includes the following step:

A. with impact style one sheet metal is carried out once above processing, with the front side shell face that forms this frame, stepped ladder locating face and outer shell face portion, but the location end face does not form in this step as yet;

B. inside has been installed with housing within the diffuser, has inserted in the frame and by the rear end of frame inner housing is fixed in wherein with welding manner;

C. with impact style the outer shell surface rear end of frame partly being processed makes it form this positioning end face portion.

8. the manufacture method of the pump shell structure of multi-stage sheet-metal working pump as claimed in claim 7, wherein, this manufacturing step b further includes:

B1. respectively two sheet metals are carried out once above processing with impact style, with front half part and the latter half part that forms an inner housing respectively, this front half part comprises side shell face portion within the interior edge face part of inner housing and the only about half of length at least, and this latter half part comprises side shell face portion and end, location within the only about half of length of inner housing at least;

B2. with the front half part front end of inner housing and the front end of diffuser, be placed in the location of the front end inner surface in the frame, the front half part front end and the diffuser of inner housing interfix with welding manner in advance;

B3. insert the latter half part of inner housing in the frame and corresponding to this front half part, and process, forward and backward half one of inner housing is combined into one and is fixed in simultaneously on the inner surface of outer shell face of frame in the spot welding mode.

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