JP7478528B2 - Canned Motor Pump - Google Patents

Description

The present invention relates to a canned motor pump.

Canned motor pumps have a structure in which the motor section is integrated into the pump section, and are compact and leak-free, making them particularly suitable for use in chemical plants.

In this type of canned motor pump, the motor section and bearings are cooled and the bearings are lubricated by directing a portion of the pressurized liquid from the discharge section of the pump casing through a bypass pipe to the motor section (see Patent Document 1).

Japanese Patent Application Laid-Open No. 9-68187

However, in conventional canned motor pumps, if the liquid flowing through the bypass pipe contains trace amounts of salt, electrolytic corrosion can occur in the motor bearings.

The present invention was devised to address the above-mentioned problems and to effectively solve them. The object of the present invention is to provide a canned motor pump that can suppress electrolytic corrosion of the motor caused by salt contained in the liquid.

The canned motor pump of the present invention is equipped with a bypass pipe that guides a portion of the pressurized liquid from the discharge section of the pump casing to the motor section, and an ion exchange filter that adsorbs chloride ions contained in the liquid is provided midway along the bypass pipe.

According to the present invention, an ion exchange filter is provided in the bypass pipe, so that chloride ions contained in the liquid are adsorbed by the ion exchange filter, reducing their intrusion into the motor section. This can suppress electrolytic corrosion of the motor section caused by salt contained in the liquid.

In the canned motor pump according to the present invention, the bypass pipe may be provided with an orifice for adjusting the flow rate, and the ion exchange filter may be disposed upstream of the orifice. In this manner, the chlorine ions in the liquid are adsorbed by the ion exchange filter, thereby reducing corrosion of the bypass pipe caused by trace amounts of salt, and preventing the rust from clogging the orifice and reducing the cooling efficiency.

In the canned motor pump according to the present invention, the ion exchange filter may be disposed upstream of the center of the bypass pipe.

In the canned motor pump according to the present invention, the bypass pipe has a first pipe connected to the discharge section, a second pipe connected to the motor section, and a union connecting an end of the first pipe to an end of the second pipe, and the ion exchange filter may be disposed inside the end of the first pipe or the end of the second pipe.

In the canned motor pump according to the present invention, the bypass pipe has a first pipe connected to the discharge section, a second pipe connected to the motor section, and a container with a lid connecting an end of the first pipe to an end of the second pipe, and the ion exchange filter may be disposed inside the container with a lid.

According to the present invention, it is possible to suppress electrolytic corrosion of the motor caused by salt contained in the liquid in a canned motor pump.

FIG. 1 is a cross-sectional view showing a canned motor pump according to an embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining an example of the arrangement of an ion exchange filter in the canned motor pump of FIG. FIG. 3 is a perspective view for explaining another example of the arrangement of the ion exchange filter in the canned motor pump of FIG.

The following describes an embodiment of the present invention with reference to the drawings. Note that the embodiment described below is merely an example of how the present invention can be implemented, and the present invention is not limited to the specific configuration described below. When implementing the present invention, a specific configuration appropriate to the embodiment may be adopted as appropriate.

Figure 1 is a cross-sectional view showing a canned motor pump according to one embodiment of the present invention.

As shown in FIG. 1, the canned motor pump 10 of this embodiment includes a pump section 10a and a motor section 10b provided adjacent to the pump section 10a.

The pump section 10a has a shaft body 23, an impeller 22 attached to the end of the shaft body 23, a pump casing 15 that houses the impeller 22, and a casing cover 20 that covers the opening of the pump casing 15. The pump casing 15 has an intake section 15a with an intake port, and a discharge section 15b with a discharge port. The casing cover 20 has an opening through which the shaft body 23 passes, and a first bearing 53 that supports the shaft body 23 is attached to the inner circumference of this opening.

In the illustrated example, a first thrust plate 57, a first shaft sleeve 55, and a distance piece 59 are fitted in this order to the end of the shaft body 23, and are fixed together with the impeller 22 by bolts. The first shaft sleeve 55 is disposed opposite the first bearing 53, preventing damage to the shaft body 23 due to sliding with the first bearing 53.

On the other hand, the motor section 10b has a rotor 24 fixed to the shaft body 23, a stator 25 arranged on the outside of the rotor 24, a cylindrical first can 60 arranged coaxially with the shaft body 23 inside the stator 25 and one end of which is sealed by the casing cover 20, and an end cover 17 which seals the other end of the first can 60. A second bearing 54 which supports the shaft body 23 is attached to the center of the end cover 17.

In the illustrated example, a second thrust plate 58 and a second shaft sleeve 56 are fitted in this order to the end of the shaft body 23 on the end cover 17 side and fixed with bolts. The second shaft sleeve 56 is disposed opposite the second bearing 54, preventing damage to the shaft body 23 due to sliding with the second bearing 54.

As shown in FIG. 1, the internal space of the first can 60 is connected to the internal space of the pump casing 15 through an opening in the casing cover 20, and is filled with liquid during operation of the canned motor pump 10. In the illustrated example, the rotor 24 is covered by a cylindrical second can 61, which prevents the rotor 24 from corroding due to the liquid filling the internal space of the first can 60.

In the illustrated example, the first can 60 has an internal space formed with a first space 31 between the rotor 24 and the first bearing 53, a second space 32 between the rotor 24 and the second bearing 54, and a third space 33 between the end cover 17 and the second bearing 54. In addition, the first bearing 53 and the first shaft sleeve 55 form a first flow path 41, the end face of the first bearing 53 and the first thrust plate 57 form a second flow path 42, the first can 60 and the second can 61 form a third flow path 43, the end face of the second bearing 54 and the second thrust plate 58 form a fourth flow path 44, and the second bearing 54 and the second shaft sleeve 56 form a fifth flow path 45.

As shown in FIG. 1, the canned motor pump 10 is provided with a bypass pipe 14 that guides a portion of the pressurized liquid from the discharge portion 15b to the pump portion 10a. One end of the bypass pipe 14 is connected to the discharge portion 15b of the pump casing 15, and the other end of the bypass pipe 14 is connected to the end cover 17 of the motor portion 10b. An orifice 16 is provided midway through the bypass pipe 14 to adjust the flow rate of the liquid flowing through the bypass pipe 14.

Part of the liquid taken out from the discharge section 15a flows into the internal space of the first can 60 of the motor section 10b via the bypass pipe 14 and the orifice 16 due to the pressure difference, passes through the opening of the casing cover 20, and is returned to the suction section 15a of the pump section 10a. This circulation of liquid cools the motor section 10b and the bearings 53, 54 and lubricates the bearings 53, 54.

The bearings 53 and 54 are made of, for example, carbon, and the shaft sleeves 55 and 56 that slide against the bearings 53 and 54 are made of, for example, stainless steel with a hard plating or spray coating on the sliding surfaces.

In this embodiment, an ion exchange filter 11 that adsorbs chloride ions contained in the liquid is provided midway through the bypass pipe 14.

The ion exchange filter 11 is preferably disposed upstream of the center of the bypass pipe 14 (i.e., toward the discharge section 15b), more preferably at the most upstream side when the bypass pipe 14 is divided into thirds, and even more preferably at the most upstream side when the bypass pipe 14 is divided into fourths. The more upstream the ion exchange filter 11 is disposed, the more effectively corrosion of the bypass pipe 14 due to salt contained in the liquid can be reduced.

In the illustrated example, the ion exchange filter 11 is disposed upstream of the orifice 16. In this case, the chlorine ions in the liquid are adsorbed by the ion exchange filter 11, and corrosion of the bypass pipe 14 caused by trace amounts of salt is reduced, so that the rust that forms can be prevented from clogging the orifice 16 and reducing the cooling efficiency.

Next, the arrangement of the ion exchange filter 11 will be described in detail. Figure 2 is a diagram for explaining an example of the arrangement of the ion exchange filter 11.

As shown in FIG. 2, the bypass pipe 14 has a first pipe 14a connected to the discharge section 15b, a second pipe 14b connected to the motor section 10b, and a union 14c that connects an end of the first pipe 14a to an end of the second pipe 14b. The union 14c is itself a commercially available pipe connection part, and the first pipe 14a and the second pipe 14b can be easily separated by rotating the nut of the union 14c.

In the illustrated example, the ion exchange filter 11 is disposed inside the end of the second pipe 14b. This allows the ion exchange filter 11 to be easily attached and detached from the bypass pipe 14 by rotating the nut of the union 14c to separate the first pipe 14a and the second pipe 14b, even if the ion exchange filter 11 needs to be replaced frequently. Note that, although the ion exchange filter 11 is disposed inside the end of the second pipe 14b in the illustrated example, it may be disposed inside the end of the first pipe 14a.

Next, we will explain the operation of the canned motor pump 10 configured as described above.

First, to operate the canned motor pump 10, power is supplied to the stator 25 of the motor section 10b to generate a rotational force in the rotor 24. This causes the shaft 23 and the impeller 22 to rotate integrally with the rotor 24. The rotation of the impeller 22 causes the liquid in the pump casing 15 to flow, and the liquid is sucked in through the suction port of the suction section 15a, while the pressurized liquid is discharged from the discharge port of the discharge section 15b.

Here, a portion of the liquid taken out from the discharge section 15a passes through the bypass pipe 14 and the orifice 16, flows from the end cover 17 into the third space 33 of the pump section 10a, passes through the fifth flow path 45, the fourth flow path 44, the second space 32, the third flow path 43, the first space 31, the second flow path 42, and the first flow path 41, flows into the space 13 behind the impeller 22, passes through the balance hole 22a formed in the impeller 22, and is returned to the suction section 15a side of the pump section 10a. This path cools the motor section 10b and the bearings 53 and 54, and lubricates the bearings 53 and 54.

However, as mentioned in the section on problems that the invention aims to solve, in conventional canned motor pumps, if the liquid flowing through the bypass pipe contains trace amounts of salt, electrolytic corrosion can occur in the motor bearings.

In contrast, in this embodiment, an ion exchange filter 11 is provided in the middle of the bypass pipe 14, so that the chlorine ions contained in the liquid are adsorbed by the ion exchange filter 11 and prevented from entering the motor section 10b. This can prevent electrolytic corrosion of the motor section 10b caused by the salt contained in the liquid.

In addition, because the ion exchange filter 11 is disposed upstream of the bypass pipe 14, corrosion of the bypass pipe 14 due to trace amounts of salt is effectively reduced. In addition, because the ion exchange filter 11 is disposed upstream of the orifice 16, chlorine ions in the liquid are adsorbed upstream of the orifice 16. This can prevent rust generated in the bypass pipe 14 from clogging the orifice 16 and reducing the cooling efficiency of the motor section 10b.

When the ion exchange filter 11 has absorbed a large amount of chlorine ions and deteriorated, the operation of the canned motor pump 10 is stopped and the ion exchange filter 11 is replaced. That is, the nut of the union 14c is rotated to separate the first pipe 14a from the second pipe 14b. Since the ion exchange filter 11 is disposed inside the end of the second pipe 14b, the ion exchange filter 11 can be easily attached and detached from the bypass pipe 14 simply by separating the first pipe 14a from the second pipe 14b. Therefore, replacing the ion exchange filter 11 is extremely easy.

According to the present embodiment described above, since the ion exchange filter 11 is provided in the bypass pipe 14, the chlorine ions contained in the liquid are adsorbed by the ion exchange filter 11, and the intrusion of the chlorine ions into the motor section 10b is reduced. This can suppress electrolytic corrosion of the motor section 10b caused by the salt contained in the liquid.

In addition, according to this embodiment, since the ion exchange filter 11 is disposed upstream of the orifice 16, the chlorine ions in the liquid are adsorbed upstream of the orifice 16. This can prevent rust generated in the bypass pipe 14 from clogging the orifice 16 and reducing the cooling efficiency.

In addition, according to this embodiment, the ion exchange filter 11 is positioned upstream of the center of the bypass pipe 14, so corrosion of the bypass pipe 14 caused by trace amounts of salt can be more effectively reduced.

In addition, according to this embodiment, the first pipe 14a and the second pipe 14b of the bypass pipe 14 are connected by the union 14c, and the ion exchange filter 11 is disposed inside the end of the first pipe 14a or the end of the second pipe 14b. Therefore, the ion exchange filter 11 can be easily attached and detached from the bypass pipe 14 simply by operating the union 14c to separate the first pipe 14a and the second pipe 14b. Therefore, it is extremely easy to replace the ion exchange filter 11.

In this embodiment, the first pipe 14a and the second pipe 14b of the bypass pipe 14 are connected by a union 14c, and the ion exchange filter 11 is disposed inside the end of the first pipe 14a or the end of the second pipe 14b, but the arrangement of the ion exchange filter 11 is not limited to this.

Figure 3 is a perspective view for explaining another example of the arrangement of the ion exchange filter 11. As shown in Figure 3, in this example, the bypass pipe 14 has a first pipe 14a connected to the discharge part 15a, a second pipe 14b connected to the motor part 10b, and a lidded container 70 that connects the end of the first pipe 14a to the end of the second pipe 14b.

In the illustrated example, the lidded container 70 has a container body 71 in the shape of a rectangular cylinder with an open upper end, and a lid body 72 connected to the edge of the upper end of the container body 71 using a hinge. The ion exchange filter 11 is made of resin and has a rectangular parallelepiped shape, and is arranged to be housed inside the container body 71.

A gasket 73 is provided on the end surface surrounding the opening at the upper end of the container body 71. When the lid body 72 rotates about the hinge to cover the opening of the container body 71, the gasket 73 is sandwiched between the lid body 72 and the container body 71. This allows the lidded container 70 to be sealed.

According to this embodiment, the ion exchange filter 11 can be easily attached and detached from the container body 71 simply by rotating the lid 72 about the hinge and removing it from the opening of the container body 71. Therefore, even with this embodiment, it is extremely easy to replace the ion exchange filter 11.

The shape of the lidded container 70 is not limited to a rectangular tube shape, but may be, for example, a cylindrical shape.

10 Canned motor pump 10a Pump section 10b Motor section 11 Ion exchange filter 13 Space behind impeller 14 Bypass pipe 14a First pipe 14b Second pipe 14c Union 15 Pump casing 15a Suction section 15b Discharge section 16 Orifice 17 End cover 20 Casing cover 22 Impeller 23 Shaft body 24 Rotor 25 Stator 31 First space 32 Second space 33 Third space 41 First flow path 42 Second flow path 43 Third flow path 44 Fourth flow path 53 First bearing 54 Second bearing 55 First shaft sleeve 56 Second shaft sleeve 57 First thrust plate 58 Second thrust plate 59 Distance piece 60 First can 61 Second can 70 Lidded container 71 Container body 72 Lid 73 Gasket

Claims (5)

In a canned motor pump,
a bypass pipe for directing a portion of the pressurized liquid from the discharge portion of the pump casing to the motor portion;
A canned motor pump characterized in that an ion exchange filter that adsorbs chloride ions contained in the liquid is provided in the middle of the bypass pipe. An orifice for adjusting the flow rate is provided in the bypass pipe,
2. The canned motor pump according to claim 1, wherein the ion exchange filter is disposed upstream of the orifice. 2. The canned motor pump according to claim 1, wherein the ion exchange filter is disposed upstream of a center of the bypass pipe. The bypass pipe includes a first pipe connected to the discharge portion, a second pipe connected to the motor portion, and a union connecting an end of the first pipe and an end of the second pipe,
4. The canned motor pump according to claim 1, wherein the ion exchange filter is disposed inside an end of the first pipe or an end of the second pipe. the bypass pipe includes a first pipe connected to the discharge portion, a second pipe connected to the motor portion, and a container with a lid connecting an end of the first pipe and an end of the second pipe;
4. The canned motor pump according to claim 1, wherein the ion exchange filter is disposed inside the container with a lid.