KR100320288B1 - Mainstream Pump - Google Patents

Abstract

A full-circumferential flow pump includes a motor having a stator, a shaft rotatably disposed in the stator, and a rotor mounted on the shaft for rotation relative to the stator, an outer frame casing (25) disposed around the stator, an outer cylindrical pump casing (5) disposed around the outer frame casing with an annular space (40) defined therebetween, and a pump assembly mounted on an end of the shaft for pumping a fluid into the annular space (40). The outer cylindrical pump casing has a suction window (5a,5b) for introducing a fluid therethrough. A suction case (10) is mounted on the outer cylindrical pump casing (5) for introducing a fluid therethrough and through the suction window (5a,5b) into the pump assembly, the suction casing having a suction port defined therein. <IMAGE>

Description

Mainstream pump

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a mainstream pump, and more particularly to a mainstream pump in which an impeller is mounted at the end of the shaft of the motor and an annular space is formed around the motor.

Known pumps in which the fluid being handled flow around the motor in the circumferential direction are published in German Laid-Open Publication No. 1653692 (DE 1653692). In this pump, the shaft is rotated manually and the pump assembly is assembled without separation of the piping.

FIG. 17 shows such a known pump. As shown in FIG. 17, the pump has a stator 101 and a block-shaped housing 100 consisting of a rotor 102 positioned and forming a small gap in the stator 101. Impellers 103 and 104 are mounted at each end of the shaft of the rotor 102. The fluid being handled is separated into two fluid streams pressurized by respective impellers 103 and 104 which are introduced and rotated from the inlet 105. The fluids applied to the impellers 103, 104 are combined and then discharged from the outlet 106.

However, in a known pump, the stator 101 is subjected to uneven pressure and is susceptible to various mechanical damages. In particular, there are three areas on the outer circumference of the motor, which are:

(1) an area in which fluid flows under inlet suction pressure;

(2) an area in which fluid flows under an outlet discharge pressure; And

(3) It contains the area | region where a fluid does not flow.

Therefore, there is a possibility that an uneven pressure or external force is applied to the stator 101 and the stator 101 is stressed or deformed.

The motor is more likely to be subjected to mechanical warping, especially if the outer motor frame casing is made of thin metal or the fluid discharge pressure is high. Furthermore, since the external motor frame casing and the external pump casing are integrally formed with each other in the pump disclosed above, there is a possibility that the motor may malfunction when subjected to an external force due to a pipe load or the like.

Accordingly, an object of the present invention is to equalize the external force or pressure applied to the outer motor frame casing surrounding the motor stator to prevent the motor frame from being stressed or deformed, and can be assembled internally without separation of pipes. To provide a pump.

According to one aspect of the present invention, there is provided a mainstream pump, comprising: a stator and a rotor mounted on the shaft and disposed inside the stator to rotate relative to the stator; A motor having an outer frame casing surrounding the stator; An outer cylindrical pump casing disposed around the outer frame casing to form an annular space between the casing, and having a suction window for entering and exiting a fluid; A pump assembly mounted at one end of the shaft to pump a fluid into the annular space; And a suction case mounted on an outer circumferential surface of the outer cylindrical pump casing and sucking fluid to be sent to the pump assembly through the suction window, and having a suction port therein.

Fluid sucked through the inlet flows through the suction case into the pump assembly and into the impeller mounted at the end of the shaft of the motor. The fluid discharged by being pressed by the impeller flows into the annular space or passage formed between the outer cylindrical pump casing and the outer frame casing. Since the outer circumferential wall of the outer frame casing is surrounded by the fluid and discharged from the pump, the outer circumferential wall of the outer frame casing is subjected to uniform fluid pressure so that it is not unevenly stressed or deformed.

According to another aspect of the present invention, in a mainstream dual suction pump, a motor having a stator, a rotor mounted on the shaft and disposed on the stator and rotating relative to the stator, and an outer frame casing surrounding the stator. Wow; An outer cylindrical pump casing disposed around the outer frame casing to form an annular space therebetween, and having a pair of suction windows near each axial end and an outlet formed therein in communication with the annular space between the suction windows; ; A pair of pump assemblies mounted at opposite ends of said shaft for pumping fluid into said annular space; And a suction case formed in the suction port for sucking fluid into the pump assembly through the suction window, and mounted on an outer circumferential surface of the outer cylindrical pump casing.

In a mainstream double suction pump, the fluid entering through the inlet is separated into fluid flows leading into each pump assembly where the fluid flow is pressurized by the impeller. Fluid flows pressurized by the impeller and discharged from the impeller flow into the annular space or passageway formed between the outer cylindrical pump casing and the outer frame casing. While flowing through the annular space or passageway, the fluid flows are combined with each other and discharged to the outlet.

These and other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, which illustrate, by way of example, preferred embodiments of the invention.

The mainstream pump according to the present invention is shown in FIGS. 1 to 4A and 4B. As shown in FIG. 1, the mainstream pump is a double suction type and has a canned motor 1 disposed at an inner center thereof. The canned motor 1 has a shaft 2 having a pair of impellers 3A, 4A, 3B, and 4B mounted on opposite ends, each having an suction area open outward in the axial direction. Include. Thus, the two pump assemblies are respectively arranged on opposite sides of the canned motor 1, and these two pump assemblies have the same shutoff head but different flow rates. The cand motor 1 and the impellers 3A, 4A, 3B and 3B are housed in an outer cylindrical pump casing 5 and a pair of spaced end covers 6 and 7. The end covers 6 and 7 are detachably fixed to the respective axial ends of the outer cylindrical pump casing 5 by the flanges 8 and 9.

In the outer cylindrical pump casing 5, a pair of suction windows 5a, 5b are formed near each coaxial end, and a suction case 10 is mounted on the outer surface of the outer cylindrical pump casing 5 for suction. The windows 5a and 5b are connected to each other. The suction case 10 is a cup-shaped case 10 of a substantially rectangular shape having a bottom at one end and an opening at another end. A suction nozzle 11 is provided on the bottom of the suction case 10. As shown in FIG. 2, the suction case 10 has a width W ₂ , and the suction windows 5a and 5b have a circumferential width W _{1 which} is approximately equal to W ₂ , so that air is absorbed by the suction case 10. Not caught The suction flange 12 is mounted on the suction nozzle 11 in which the entrance 11a is formed.

As shown in FIG. 1, the two axially spaced bulkheads 15, 16 have an outer cylindrical pump casing around each pair of impellers 3A, 4A, 3B, and 4B. 5) It is mounted inside. The partition walls 15 and 16 have respective axial openings 15a and 16a to which each seal member 17 made of elastic material such as rubber is fixed, and the suction openings 15c and 16c are provided. And bottom portions 15b and 16b respectively formed therein.

The first inner casings 18A and 18B are disposed in each of the partition walls 15 and 16, and the second inner casings 19A and 19B are disposed in the respective partition walls 15 and 16. The first inner casings 18A and 18B have respective return vanes 18a for guiding fluid from the first stage impellers 3A and 3B to the second stage impellers 4A and 4B. The second inner casings 19A and 19B have respective guides 19a acting as guide vanes or bowls for guiding fluid. The second inner casings 19A and 19B have respective socket-spigot joints installed on the motor frame 24 of the canned motor 1. The seal member 20 is provided between the first inner casings 18A, 18B and the partition walls 15, 16, respectively, and the suction pressure side (low pressure side) in communication with the suction windows 5a, 5b. And the discharge pressure side (high pressure side) in communication with the annular space 40 (described later). The liner ring 21 is mounted at the radially inner ends of the first inner casings 18A, 18B and the second inner casings 19A, 19B, respectively.

The motor frame 24 of the canned motor 1 includes a pair of axially spaced side frame members 26 fixed to the axial open ends of the outer frame casing 25 and the outer frame casing 25, respectively, It consists of 27. The cable housing 22 is welded to the outer frame casing 25. Lead extends outward from the motor coil of the outer frame casing 25 and is electrically connected to the power cable 46 of the cable housing 22. The power cable 46 is fixed by a cable connector 47 which is welded to the cable housing 22.

The canned motor 1 includes a stator 28 and a rotor 29 disposed on the motor frame 24. The rotor 29 is embedded in a cylindrical can 30 supported on the shaft 2 and installed in the stator 28.

The bearing housings 31 and 32 are detachably fixed to the side frame members 26 and 27 by gapless socket-spigot joints and elastic O-rings 37 and 38, respectively. The bearing housings 31, 32 fix each radial bearing 33, 34 on their radially inner end. The shaft sleeve 35 installed on the shaft 2 is rotatably supported by the radial bearing 33, and the shaft sleeve 36 installed on the shaft 2 is rotatably supported by the radial bearing 34.

As shown in FIG. 1 and FIG. 2, the annular space 40 is formed between the outer cylindrical pump casing 5 and the motor frame 24. As shown in FIG. The outer cylindrical pump casing 5 has an opening 5c formed in the circumferential wall thereof and fixed to communicate with the annular space 40. The discharge nozzle having the discharge port 41a formed therein is attached to the outer cylindrical pump casing 5 around the opening 5c, and the discharge flange 42 is attached to the discharge nozzle 41.

The process of fixing the canned motor 1 and the outer cylindrical pump casing 5 to each other is described below with reference to FIG.

First, as shown in FIG. 3, the side frame members 26, 27 and the cable housing 22 are welded to the outer frame casing 25, and the support 43 is welded to the outer frame casing 25. To form the motor frame assembly 50.

Next, the motor frame assembly 50 is inserted into the outer cylindrical pump casing 5, and the cable housing 22 is inserted into a hole 5d formed in the outer cylindrical pump casing 5.

Thereafter, a drain pipe 45 having a notch 45a formed therein is inserted through a hole formed in the outer cylindrical pump casing 5 to press the outer frame casing 25, and then the drain pipe 45 is an outer cylindrical pump. It is welded to the casing 5. Since the end of the notch 45a is engaged with the outer frame casing 25, the outer frame casing 25 and the outer cylindrical pump casing 5 are fixed to each other.

4A and 4B show the mainstream dual suction pump in front and side, respectively. As shown in Figs. 4A and 4B, the mainstream dual suction pump is of the side-top type with the inlet port 11a on the side and the outlet port 41a on the upper surface. The legs 48 mounted on the base 49 are fixed to the flanges 8 and 9 which interconnect the outer cylindrical pump casing 5 and the end covers 6 and 7.

The operation of the mainstream dual suction pump having the above structure will be described below.

The fluid introduced through the suction port 11a is separated into the suction case 10 by two fluid flows introduced into the pump assembly through the suction windows 5a and 5b by the suction case 10. The fluid flow introduced into the pump assembly is made through the suction openings 15c and 16c and the fluid flow is pressurized by the fluid flow discharged from the impellers 3A, 3B, 4A and 4B. It flows into 1st inner casing 18A, 18B, and 2nd inner casing 19A, 19B. The fluid flow discharged from the impellers 3A and 3B flows into the impellers 4A and 4B causing the fluid to flow radially outward through the guide 19a and then in the axial direction with the outer cylindrical pump casing 5 and It flows into the annular space or passage 40 between the motor frames 24. The fluid flow flowing through the annular passage 40 merges in the middle of the annular passage 40 and is then discharged from the outlet 41a through the opening 5c and the discharge nozzle 41 of the external outer cylindrical pump casing 5. .

Since the outer frame casing 25 is surrounded by the entirety of the fluid, it is subjected to uniform pressure and does not deform. The partition walls 15 and 16 mounted on the outer cylindrical pump casing 5 are effective for separating the inner space of the outer cylindrical pump casing 5 to the suction pressure side and the discharge pressure side of the pump, and these are the external cylindrical pump casing 5 ) Make the radial and circumferential pressure distribution uniform.

Since the elastic sealing member 17 is disposed between the inner circumferential surface of the outer cylindrical pump casing 5 and the outer circumferential surface of the partition walls 15 and 16, the partition walls 15 and 16 are the outer cylindrical pump casing 5. ), The suction and discharge pressure sides can be reliably separated from each other.

Removable covers 6, 7 on each opposing end of the outer cylindrical pump casing 5 enable assembly of the internal mechanism of the pump without piping separation. The canned motor pump is mainly assembled with sliding and rotatable elements such as bearings, liner rings, etc., and if the covers 6 and 7 are removed, the rotatable element and bearing assembly can be disassembled if the piping is not separated. have.

Since the mainstream pump is double suction, the fluid entering the pump is separated and operated by two pump assemblies. The specific speed of the pump can be expressed as Ns = 1 / (2) ^1/2 , and each of the impellers 3A, 3B, 4A, and 4B consists of two-dimensional vanes whose shape can be easily pressed. Can be. In general, the motor driving the pump can be smaller because it can rotate at high speed. In the pump, the head is proportional to the square of the rotational speed and the flow rate is proportional to the rotational speed. Also, in the pump, the head and the flow rate are proportional to the square of the outer diameter of the impeller. Thus, motors and pumps can be made smaller because they can rotate at high speeds.

However, as the speed of rotation of the impeller increases, the rate of increase of the head is greater than the rate of increase of the flow rate. As a result, the Q-H curve tends to increase significantly.

When the single suction pump is operated at high speed, the specific velocity Ns of the pump becomes very large in order to achieve a high flow rate and a low head. The specific velocity Ns is expressed as follows.

Ns = nQ ^1/2 / H ^3/4

Where H is the head, Q is the flow rate, and n is the rotational speed.

In general, the impeller having a low specific speed has a shape as shown in FIG. 5A, and the impeller having a high specific speed has a shape as shown in FIG. 5B. In other words, the impeller having a low specific velocity has a two-dimensional wing B as in FIG. 5C. As the specific velocity increases, the shape of the wing becomes three-dimensional, as in Figure 5D. Impellers with three-dimensional wings have difficulties in manufacturing compared to impellers with two-dimensional wings. In particular, in the case of an impeller manufactured by compression processing, it is difficult to manufacture an impeller having a three-dimensional wing.

However, in the present invention, since an impeller having a small specific speed can be used, the impeller may be composed of a two-dimensional wing that can be easily pressed in shape.

It is known that the higher the velocity of the fluid at the inlet of the impeller, the worse the pump suction performance when the pump is in operation. However, since the introduced fluid is handled by two pump assemblies, the double suction pump has a high suction performance.

Dual suction pumps can minimize the load capacity of the bearing as the axial thrust generated by the pump is balanced. A balanced axial thrust allows the bearing housings 31, 32 to be fixed to the motor frame 24 in a simple configuration. In particular, since the bearing housings 31 and 32 are fixed to the motor frame 24 via the gapless socket-spigot joint and the elastic O-rings 37 and 38, the radial bearing 33, 34 can be automatically centered, and the elements associated with the radial bearings 33, 34 need not be processed and assembled with high precision. In this embodiment, the double suction pump is particularly effective in the high speed range of 4,000 r.p.m or more from the viewpoint of power and axial thrust force.

In this embodiment, the pressure in the region before and after the rotor chamber, ie the chamber in which the rotor 29 is located, is in full parallel. As a result, the slurry does not enter the rotor chamber. If each impeller is provided with a pump-out vane behind the vane, any slurry approaching the rear side of the impeller will be forced out radially outward. Therefore, the pump has a structure that can withstand the slurry solution very well.

Further, the outer frame casing 25 and the side frame members 26, 27 are welded before the outer cylindrical pump casing 5 is welded. Therefore, the opposite end of the outer cylindrical pump casing 5 is extended, the suction case 10 is mounted on the outer cylindrical pump casing 5, and the suction windows 5a, 5b are mounted on the outer cylindrical pump casing 5. It is possible to form Therefore, it is not necessary to provide a header pipe or the like for interconnecting the suction windows 5a and 5b.

6 to 10 show a mainstream pump according to a second embodiment of the present invention. The mainstream pump according to the second embodiment is of dual suction type and is essentially the same as the mainstream pump according to the first embodiment shown in FIGS. 1 to 4A and 4B. Parts of FIGS. 6-10 which are the same as shown in FIGS. 1-4A and 4B are designated by like reference numerals and will not be described in detail below.

According to the second embodiment, as shown in Figs. 6 and 7A, the outer cylindrical pump casing 5 has respective suction windows 5a, 5b formed in the outer cylindrical pump casing 5 (Fig. 7A). In this case, only the suction window 5a is shown to extend the axial bar 51 in the axial direction. This axial bar 51 allows the partition walls 15 and 16, on which the seal member 17 is mounted, to be easily inserted into the outer cylindrical pump casing 5 above the suction windows 5a and 5b. . In order to prevent air from being blocked by the suction case 10, the suction windows 5a and 5b have a circumferential width W ₁ which is almost equal to the width W ₂ of the suction case 10 as shown in FIG. 7B. As such, the air will not be blocked in the suction case 10.

As shown in FIG. 8, a stopper 52 is attached to the distal end of each of the partition walls 15 and 16 (only the partition wall 15 is shown in FIG. 8) to secure the seal member 17 without being transferred. I can do it. The outer cylindrical pump casing 5 allows the partition walls 15 and 16 on which the seal member 17 is mounted to be easily inserted into the outer cylindrical pump casing 5 above the suction windows 5a and 5b. To this end, an enlarged casing portion 5d (only one casing portion 5d is shown in FIG. 8) is provided on the suction pressure side. The enlarged casing portion 5d prevents the suction windows 5a and 5b from being deformed in the direction of the arrow in FIG. 8 due to the pressure difference between the inside and the outside of the outer cylindrical pump casing 5. The enlarged casing portion 5d is more effective for maintaining the outer cylindrical pump casing 5 in a cylindrical strong structure.

According to the second embodiment, as shown in FIG. 6, the frequency converter 54 is fixed to the outer side of the cover 6 which seals one end of the outer cylindrical pump casing 5 and is covered with the cover 55. have. Since the frequency converter 54 is fixed to the cover 6 fixed in contact with the fluid being handled, the frequency converter 54 can be effectively cooled. Highly integrated circuits such as frequency converters are generally susceptible to external forces or vibrations. The frequency converter 54 is more reliable by being mounted on the cover 6 which receives only the suction pressure of the pump, rather than being mounted on the outer circumferential surface of the outer cylindrical pump casing 5 which can be deformed or deformed by the discharge pressure of the pump. This will increase and prevent damage.

The plug 56, which can be removed by the user to confirm the possibility of manual rotation of the rotatable assembly of the pump, is detachably mounted to the cover 7 closing the other end of the outer cylindrical pump casing 5. The plug 56 allows the user to confirm the manual rotatableness of the rotatable assembly without removing the cover 7. Specifically, the user removes the plug 56, inserts the front end of the screw driver into the slot 2a formed at the end of the shaft 2, and turns the screw driver to confirm that the rotatable assembly can be rotated. After that, the plug 56 is attached again.

As shown in FIGS. 6 and 9, the outer cylindrical pump casing 5 has an opening 5e formed in its outer circumferential wall and communicating with the annular space 40, and the discharge nozzle 57 has an opening 5e. Welded to the outer circumferential wall of the outer cylindrical pump casing (5). The discharge nozzle 57 has a discharge port 57a formed therein, and the discharge flange 58 is welded to the discharge nozzle 57 near the discharge port 57a. The discharge flange 58 is welded to the reinforcing member 59 which is in turn welded to the outer circumferential surface of the outer cylindrical pump casing 5. The discharge flange 58 and the reinforcing member 59 welded in this way protect the discharge nozzle 57 from an external force due to a pipe load or the like. Since the external force applied to the pump is absorbed by the outer cylindrical pump casing 5, the external force damaging the pump is not directly applied to the outer frame casing 25 and the stator 28. Even if the reinforcing member 59 is not provided, the external force is not transmitted to the outer frame casing 25 because the pump is a full double wall structure unlike the conventional art. As shown by the dotted line in FIG. 9, the reinforcing member 59 is mounted on the outer circumferential wall of the outer cylindrical pump casing 5 so that the outer cylindrical pump casing 5 does not expand radially outward under the internal pressure of the pump.

FIG. 10 is a perspective view of the mainstream dual suction pump shown in FIG. As shown in FIG. 10, the mainstream double suction pump has a side and top surface in which the inlet port 11a is positioned on the side and the outlet port 57a is located on the upper surface.

11 shows a mainstream pump according to a third embodiment of the present invention. The mainstream pump according to the third embodiment is a single suction type. Parts in FIG. 11 that are the same as those in FIG. 6 are designated by like reference numerals and will not be described in detail below.

As shown in FIG. 11, the mainstream type single suction pump according to the third embodiment includes a canned motor 1 at the center of the majority. The canned motor 11 has an intake area open axially outward at one end thereof. And a shaft 2 supporting a pair of impellers 3A and 4A each having. The impeller is not attached to the opposite end of the shaft 2, and the partition in the outer cylindrical pump casing 5 around the other end of the shaft 2 is not arrange | positioned. Other details of the pump shown in FIG. 11 are generally the same as those of the pump of FIG.

The mainstream type single suction pump shown in FIG. 11 operates as follows: Fluid sucked through the suction port 11a flows into the pump assembly through the suction window 5a of the suction case 10. The fluid introduced into the pump assembly flows through the suction opening 15c into the inner casings 18A and 19A through which the fluid is pressurized by the impellers 3A and 4A. The fluid discharged from the impeller 3A flows into the impeller 4A which causes the fluid to flow radially outward through the guide 19a, and then the annular space formed between the outer cylindrical pump casing 5 and the motor frame 24 or Flow into passage 40. The fluid is then discharged from the discharge port 57a through the discharge nozzle 57. Except for its original operating characteristics and advantages, the mainstream single-suction pump of FIG. 11 operates in the same way and has the same advantages as the mainstream double-suction pump shown in FIGS.

As described above, the mainstream pump according to the preferred embodiment of the present invention has the following characteristics.

Since the outer frame casing is surrounded by the fluid exiting the pump, the outer frame casing is subjected to uniform pressure and there is no irregular deformation. The partition wall of the outer cylindrical pump casing separates the inner space of the outer cylindrical pump casing into the suction pressure side and the discharge pressure side of the pump, thereby making the radial circumferential pressure distribution uniform in the outer cylindrical pump casing.

Since a rubber-like elastic sealing member is interposed between the inner circumferential surface of the outer cylindrical pump casing and the outer circumferential surface of the partition, the partition can be separated from the outer cylindrical pump casing, so that the suction and discharge pressure sides can be reliably separated from each other.

Removable covers on each opposite end of the outer cylindrical pump casing allow the internal mechanism of the pump to be assembled without piping separation. The canned motor pump is mainly assembled with a slidable and rotatable element such as a bearing, liner ring, etc., and when the cover is removed, the rotatable element and bearing assembly can be separated even if the piping is not separated.

In the case where the mainstream pump is double suction, the fluid hydraulically pumped is separated and handled by two pump assemblies. The specific velocity of the pump is expressed as Ns = 1 / (2) ^1/2 , each impeller consisting of two-dimensional vanes, which can be easily shaped by the pressurization process.

Since the flange connecting the outer cylindrical pump casing and its end cover is supported on the leg so that the fluid flows around the motor as a whole, the pump can be effectively cooled, and thus the motor can be scaled down.

The fluid being handled freely flows into and out of the rotor chamber. The motor can be cooled by the fluid and thus can be relatively small. Since it is not necessary to provide a watertight seal between the rotor chamber and the pump assembly and the axial thrust is in parallel, the radial bearing can be fixed to the motor frame in a simple configuration. Clearly, since the bearing housing is fixed to the motor frame by a gapless socket-spigot joint and an elastic O-ring, the radial bearing can be automatically centered, and the element combined with the radial bearing is highly precise There is no need for road processing and assembly.

Pump assemblies arranged on opposite sides of the motor have different flow rates or capacities. For example, if a pump assembly having a flow rate ratio of 1: 1.6 is useful for the use of various elements, three pumps having flow rates of 2 (1 + 1), 2.6 (1 + 1.6), and 3.2 (1.6 + 1,6) may be used. It is possible to build a pump.

Since the pressure in the region before and after the rotor chamber is perfectly parallel, the slurry does not enter the rotor chamber. If each impeller is equipped with a pump-out vane, any slurry approaching the backside of the impeller will be forced out radially outward. Thus, the mainstream pump is very resistant to slurry solutions.

Since the air is not blocked by the intake case, the pump does not cause problems in operation that may be caused by blocked air. Since there is no need to provide a header pipe or the like for interconnecting the suction window, the pump assembly can be assembled without separation of the piping.

Furthermore, in the case where the multistage dual suction pump is configured, the outer circumferential passage is formed by using the partition wall, and the suction cover can be disposed on the outer circumferential passage. This configuration makes it possible to shorten the overall length of the multistage double suction pump.

Next, another form of the double suction pump will be described below with reference to FIGS. 12 shows a double suction pump according to a fourth embodiment of the present invention. As shown in FIG. 12, the double suction pump has a casing composed of an upper casing 61 and a lower casing 62. As shown in FIG. The lower casing 62 has an inlet port 62a and an outlet port (not shown). The double suction impeller 70 is disposed in the casing. The double suction impeller 70 is fixed to a shaft 63 rotatably supported by bearings 64 and 65 at both ends thereof. The sealing devices 66 and 67 are provided in the part through which the shaft 63 passes through a casing.

The double suction impeller 70 of the double suction pump will be described in detail below with reference to FIG. As shown in FIG. 13, the double suction impeller 70 has a main plate 71 whose central portion has a boss 71a for transmitting a driving force from the shaft 63 to the impeller 70. The boss 71a is formed of a keyway 71b into which the key 68 (see FIG. 12) is inserted, so that driving force is transmitted from the shaft 63 to the boss 71a. A plurality of A-wings 74 and A-side plates 72 are provided on one side of the main plate 71. The outer diameter of the main plate 71 coincides with the outer diameter of the A-wing 74 and the A-side plate 72.

A plurality of B-wings 75 and B-side plates 73 are provided on the other side of the main plate 71. The outer diameter of the B-wing 75 is equal to the outer diameter of the B-side plate 73, and the outer diameters of the B-wing 75 and the B-side plate 73 are smaller than the outer diameter of the main plate 71. The span of the A-wing 74 is longer than the span of the B-wing 75, ie B _2A > B _{2b in} FIG. 13. Liner rings 76 and 77 are provided with small gaps around A-side plate 72 and B-side plate 73, respectively.

A-side plate 72, A-wing 74 and main plate 71 together form impeller element A, B-side plate 73, B-wing 75 and main plate 71 ) Together constitute an impeller element (B). Here, the impeller element is defined as a rotating element that imparts energy to the fluid to be pumped. The outer diameter D _2A of the impeller element A is larger than the outer diameter D _2B of the impeller element A, ie D _2A > D _{2B in} FIG. 13. Further, the diameter D _1A of the suction port of the impeller element A is larger than the diameter D _1B of the suction port of the impeller element B, that is, D _1A > D _{1B in} FIG. In this embodiment, the main plate 71, the A-wing 74, the B-wing 75, the A-side plate 72 and the B-side plate 73 are manufactured by press working, so that the double suction impeller 70 can be manufactured by welding this element.

In this embodiment, since the exit angle of the A-wing 74 is different from that of the B-wing 75 or the number of the A-wings 74 is different from that of the B-wing 75, The shutoff head (no discharge head) is the same as that of the impeller element B. This may be caused by an unbalanced pressure at the operating point of the flow rate where the backflow from the impeller element (A) to the impeller element (B) and vice versa is different if the impeller elements (A) and (B) are different from each other. have.

In the above structure, the performance characteristics of the impellers (A) and (B) are different from each other. 14A, 14B and 14C show the performance curves of the impeller elements A and B. FIG. Figure 14A shows the relationship between capacity or flow rate Q and head H, Figure 14B shows the relationship between capacity Q and power P, and Figure 14C shows capacity Q and efficiency ( ) Relationship between In FIGS. 14A, 14B and 14C, the impeller element A represents the characteristic curve 2, and the impeller element B represents the characteristic curve 1. Therefore, in the double suction pump composed of the impeller element A and the impeller element B, the capacity or flow rate Q and the power P have the capacity and power of the impeller element A in the same head. It is obtained by simply adding to the capacity and power of each. Therefore, the relationship between the capacity and power of the double suction pump is shown by the characteristic curve 3 in FIGS. 14A and 14B. The characteristic curve of a conventional double suction pump is shown by the curve 4 in FIGS. 14A, 14B and 14C.

On the other hand, the efficiency of the impeller element (B) ) Is greater than the efficiency of the impeller element A at low flow rate and high head, and less than the efficiency of the impeller element A at high flow rate and low head. Also, the maximum efficiency of the impeller element A is greater than that of the impeller element B. In this case, the efficiency of the double suction pump constituting the impeller element A and the impeller element B is obtained as an average of the efficiency of the impeller elements A and B. As a result, the efficiency characteristic curve of the double suction pump tends to have a relatively small maximum efficiency and a smaller change in efficiency than the total capacity. Therefore, the efficiency characteristic curve tends to be slowly inclined.

In addition, the thrust applied to the impeller is obtained by subtracting the inlet area from the area of the main plate and then multiplying the result by the pressure. In FIG. 13, the thrust F _A acting on the impeller element _A and the thrust F _B acting on the impeller element B are expressed by the following equation.

F _A = (π / 4) {(D _2A ² -D _1A ² )} × P

F _B = (π / 4) {(D _2A ² -D _1B ² )} × P

Since the relationship between the diameter of the inlet (D _1A ) and the diameter of the inlet (D _1B ) is D _1A > D _1B , the thrust acting on the entire impeller is expressed by the following equation.

Total Trust = F _B -F _A = (π / 4) {(D _1A ² -D _1B ² )} × P

Thus, the thrust acts in one fixed direction. The absolute value of the thrust is not so large because it is caused by the difference in diameter between the suction ports of the impeller elements (A) and (B). Thus, thrust bearings do not require large load capacities.

In the embodiment of FIG. 13, two impeller elements A and B are D _2A , D _2B ; D _1A , D _1B ; It has a variety of different factors, including B _2A and B _2B , but it is not necessary to make every factor different. In a simple way, the efficiency characteristic curve is only achievable by D _2A = D _2B , D _1A > D _1B and B _2A > B _2B , as shown in FIG. 15.

Next, an example in which two impeller elements are separated into two single suction impellers and a double suction pump is constructed using a set of two single suction impellers is described with reference to FIGS. 16A and 16B. 16A and 16B show the impeller coupled to the mainstream dual suction pump of FIG. The single suction impellers 3A and 3B constitute a set of two impeller elements. The impellers 3A and 4A have the same capacity head (QH) characteristics, and the impellers 3B and 4B have the same capacity-head (QH) characteristics, and the impellers 3A and 4A have the same characteristics. It has a different capacity-head QH than impellers 3B and 4B. In the example of FIG. 16A, the impeller 3A (or 4A) has the same factor as the impeller element A of FIG. 13, and the impeller 3B (or 4B) has the same factor as the impeller element B of FIG. Have In the example of FIG. 16B, the impeller 3A (or 4A) has the same factor as the impeller element A of FIG. 15, and the impeller 3B (or 4B) has the same factor as the impeller element B of FIG. Have That is, in the examples of FIGS. 16A and 16B, the two impeller elements A and B of FIGS. 13 and 15 are composed of single suction impellers 3A and 3B; Corresponding to 4A and 4B, respectively, the two stage double suction pump includes two sets of single stage double suction impellers 3A and 3B; It consists of 4A and 4B.

According to the embodiment of FIGS. 16A and 16B, the characteristic curves of FIGS. 14A, 14B and 14C can be achieved by providing two types of single-suction impellers having different capacity-head characteristics. As a result, the embodiments of FIGS. 16A and 16B show the same results as the embodiments of FIGS. 13 and 15. In this case, a single suction impeller can be used, and accordingly, a multistage double suction pump can be easily manufactured.

12 to 16, two impeller elements having different capacitance-head characteristics are provided in a parallel configuration, one of the impeller elements having a relatively large flow rate range, and the other impeller element having a relatively small flow rate. Has a range of. Therefore, the double suction pump has a smoothly inclined efficiency characteristic curve. Even if the operating point of the pump is changed, the efficiency can be kept at a constant level without changing.

Further, according to the embodiments of FIGS. 12-16, since the thrust acts in one fixed direction, the thrust bearing can be designed to receive the thrust from the fixed one direction. In addition, vibration of the shaft can be prevented, and as a result, noise problems can be solved.

While preferred embodiments of the invention have been described in detail, it will be understood that various modifications may be made without departing from the scope of the claims.

1 is a longitudinal sectional view of a mainstream pump according to a first embodiment of the present invention.

2 is a cross-sectional view taken along the line II-II of FIG.

3 is a cross-sectional view illustrating a process of assembling the mainstream pump according to the first embodiment.

4A and 4B are front and side views, respectively, of the mainstream pump according to the first embodiment.

5A and 5B are cross-sectional views of the impeller, respectively.

5C and 5D are perspective views of the wings, respectively.

6 is a longitudinal sectional view of a mainstream pump according to a second embodiment of the present invention.

7A is a schematic longitudinal sectional view of an external cylindrical pump of a mainstream pump according to a second embodiment.

FIG. 7B is a sectional view taken along the line VII (B) -VII (B) of FIG. 7A.

8 is an enlarged cross-sectional view of a circle A of the mainstream pump of FIG.

FIG. 9 is a cross sectional view of FIG.

10 is a perspective view of the mainstream pump of FIG.

11 is a longitudinal sectional view of a mainstream pump according to a third embodiment of the present invention.

12 is a cross-sectional view of a double suction pump according to a fourth embodiment of the present invention.

13 is a cross-sectional view of a double suction impeller according to a fourth embodiment of the present invention.

14A is a graph showing the relationship between the capacitance Q and the head H according to the fourth embodiment of the present invention.

14B is a graph showing the relationship between the capacity Q and the power P according to the fourth embodiment of the present invention.

14C shows the capacity Q and the efficiency according to the fourth embodiment of the present invention. Graph showing the relationship between).

15 is a cross-sectional view of a modified impeller according to a fourth embodiment of the present invention.

16A is a cross sectional view of the single suction impeller of FIG.

16B is a cross sectional view of the single suction impeller of FIG.

17 is a longitudinal sectional view of a conventional pump.

Claims (29)

In the mainstream pump, A motor having a stator, a rotor mounted to the shaft and disposed in the stator to rotate relative to the stator, and an outer frame casing surrounding the stator; An outer cylindrical pump casing disposed around the outer frame casing to form an annular space between the casing and a suction window for sucking fluid; A pump assembly mounted at one end of the shaft to pump a fluid into the annular space; And a suction case formed therein, the suction port for sucking fluid into the pump assembly through the suction window, and mounted on an outer circumferential surface of the outer cylindrical pump casing. The method of claim 1, And a partition wall disposed in the outer cylindrical pump casing and partitioning an inner space of the outer cylindrical pump caping into a suction pressure side communicating with the suction window and a discharge pressure side communicating with the annular space. The method of claim 2, And an elastic sealing member between an inner circumferential surface of the outer cylindrical pump casing and an outer circumferential surface of the partition wall. The method of claim 3, And a stopper mounted on the outer circumferential surface of the partition wall to prevent the sealing member from being separated. The method of claim 1, And said outer cylindrical pump casing has at least one bar extending axially above said suction window. The method of claim 1, And said outer cylindrical pump casing has an enlarged portion located on said suction pressure side. The method of claim 1, And said suction window has a circumferential width substantially equal to the width of said suction case so that air is not blocked by said suction case. The method of claim 1, And a cover detachably mounted at an axial end of the outer cylindrical pump casing. The method of claim 8, The mainstream pump, characterized in that further comprises a plug which is removable and mounted to the cover to confirm the possibility of manual rotation of the shaft. The method of claim 8, And a frequency converter mounted on an outer surface of the cover. The method of claim 1, The outer cylindrical pump casing is made of sheet metal, and the outer cylindrical pump casing has an outlet formed on its outer circumferential wall, a discharge nozzle welded to be sealed to the outer cylindrical pump casing having the outlet, and sealed to the discharge nozzle. And a reinforcing member welded to the discharge flange and the discharge flange of the outer cylindrical pump casing and the outer circumferential wall. The method of claim 1, The outer circumferential wall of the outer cylindrical pump casing is surrounded by the reinforcing member and the suction case. In the mainstream double suction pump, A motor having a stator, a rotor mounted to the shaft and disposed on the stator to rotate relative to the stator, and an outer frame casing surrounding the stator; An outer cylindrical pump casing disposed around the outer frame casing to form an annular space therebetween, and having a pair of suction windows near each axial end, and an outlet formed therein in communication with the annular space between the suction windows; A pair of pump assemblies mounted at opposite ends of said shaft for pumping fluid into said annular space; A mainstream double suction pump, comprising a suction case mounted on an outer circumferential surface of the outer cylindrical pump casing, and having a suction port formed therein to suck the fluid into the pump assembly through the suction window; . The method of claim 13, And a partition wall disposed in the outer cylindrical pump casing to divide the inner space of the outer cylindrical pump casing into a suction pressure side communicating with the suction window and a discharge pressure side communicating with the annular space. . The method of claim 13, And a pair of covers attached to each opposite end of said outer cylindrical pump casing and removable for assembling said pump assembly. The method of claim 13, The mainstream double suction pump, characterized in that it further comprises a leg mounted on the base mounted on the outer cylindrical pump casing. The method of claim 13, Each suction window has a circumferential width substantially equal to the width of the suction case such that air is not blocked by the suction case. The method of claim 13, The motor includes a canned motor comprising a bearing housing supported by the outer frame casing and a bearing supported by the bearing housing, the shaft being rotatably supported by the bearing, the bearing housing being a socket-spigot A mainstream dual suction pump, characterized in that the joint is fixed to the outer frame casing by an elastic O-ring. The method of claim 13, The motor is a mainstream dual suction pump, characterized in that rotatable at a high speed of more than 4,000 r.p.m. The method of claim 13, Wherein each pump assembly comprises at least one impeller having blades made of sheet metal. The method of claim 13, Wherein said pump assemblies have the same shut-off head but different flow rates. The method of claim 13, Wherein each pump assembly comprises at least one impeller having a vane and a pump-out vane disposed thereon. The method of claim 13, Each pump assembly includes a multi-stage impeller, a partition wall disposed at the outer cylindrical pump casing to separate an inner space of the outer cylindrical pump casing into a suction pressure side communicating with the suction window and a discharge pressure side communicating with the annular space, and a final stage. And an inner casing disposed in the partition wall in relation to the impeller of each of the pump assemblies except for the impeller, and a return wing installed at the inner casing to guide fluid from one of the impellers to a next stage impeller. Mainstream dual suction pump. The method of claim 13, And said pair of pump assembly includes a set of two impeller elements mounted on each opposite end of said shaft and having different capacity-head (Q-H) characteristics. The method of claim 24, The two impeller element is a mainstream dual suction pump, characterized in that the outer diameter is different and the suction port diameter is different from each other. The method of claim 24, The two impeller element is the mainstream type dual suction pump, characterized in that the outer diameter is the same and the suction port diameter is different. The method of claim 24, The two impeller elements are mainstream dual suction pump, characterized in that the wing width is different from each other. The method of claim 24, The two impeller element is a mainstream dual suction pump, characterized in that the exit angle of the wings are different. The method of claim 24, The two impeller element is provided with a plurality of wings, the number of wings of the impeller element is a mainstream dual suction pump, characterized in that different.