JP2000352392A - Gas seal type canned motor pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent polymerization and solidification of fluid reliably by providing, in a partition portion separating a pump portion and gas seal chamber, a communication hole for communicating a pump chamber in the pump portion and the gas seal chamber. SOLUTION: A communication hole 42 is pierced in a partition portion separating a gas seal chamber 12 and pump casing 14. Fluid is filled in a pump chamber 22 and flows into the gas seal chamber 12 when supply pressure thereof is at a prescribed level or higher. From then on, a pump operation starts and the fluid is discharged from a pump impeller 15, partially flowing through the back of the impeller 15, and flows into the gas seal chamber 12 via the communication hole 42. The fluid in the gas seal chamber 12 flows, by the amount flown therein, in an auxiliary pump chamber 36 from a communication hole 32 through an axially penetrating portion 26. Further, the fluid flows in, via a communication hole 38, to the back of the pump impeller 15, joins to fluid flowing directly from an outlet of the pump impeller 15 along its back, and circulates in the inlet side of the pump impeller 15 from a communication hole 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas seal type vertical canned motor pump, and more particularly, to a gas sealed type canned motor pump for preventing a liquid to be handled from remaining in a gas seal chamber.

[0002]

2. Description of the Related Art A gas seal type vertical canned motor pump is used in which a gas seal chamber is provided between a pump section and a motor section so that liquid handled by the pump section does not flow into the motor section. This type of pump is required to reliably prevent leakage of gas in the gas seal chamber to the pump section and increase of the liquid handled in the gas seal chamber to prevent the handled liquid from flowing into the motor section. In order to satisfy the demand, an improved pump provided in Japanese Utility Model Publication No. 110469 has already been used.

[0003] This improved pump has a configuration in which an auxiliary pump chamber in which pressure reducing blades are provided is provided in a communication section that connects the pump section and the gas seal chamber. The rotation of the pressure reducing blades makes the pressure in the auxiliary pump chamber higher than the pressure on the back side of the pump impeller in the pump section, preventing leakage of gas in the gas seal chamber to the pump section and inflow of the handled liquid into the motor section. can do. As a result, the liquid level of the handled liquid in the gas seal chamber can be constantly controlled to a stable state.

[0004] On the other hand, since the handling liquid in the gas seal chamber is stabilized, the handling liquid does not circulate or flow, and the following problems are newly encountered. In other words, since the handling liquid in the gas seal chamber is in a stagnant state, if the handling liquid has polymerization or solidification properties, the handling liquid in the gas seal chamber polymerizes or solidifies with time, causing various adverse effects. As a measure to prevent such evil,
A pump disclosed in 36146 is provided.
This pump is provided with an auxiliary pump discharge hole that communicates the discharge side of the auxiliary pump with the gas seal chamber, circulates the liquid handled in the gas seal chamber between the gas seal chamber and the auxiliary pump, and polymerizes or solidifies the liquid handled. It is to prevent.

However, even with this pump, the same liquid to be taken into the gas seal chamber only circulates in the same flow passage, and the liquid is not exchanged. Therefore, it has been incomplete to surely prevent polymerization and coagulation from occurring in the circulating liquid. In particular, there is a problem that the method cannot be applied to a handling liquid in which polymerization or coagulation inevitably occurs with the passage of time regardless of the presence or absence of circulation. In addition, since the handled liquid in the flow passage from the auxiliary pump discharge hole to the back surface of the pump impeller is retained, there still remains a problem that polymerization and coagulation easily occur.

[0006]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances, and the handling liquid in the gas seal chamber and its surrounding flow passages is constantly exchanged with a new handling liquid to flow. It is an object of the present invention to provide a gas seal type canned motor pump which reliably prevents the occurrence of polymerization and coagulation.

[0007]

According to a first aspect of the present invention, a pump section is provided below a canned motor section via a gas seal chamber.
In a gas seal type canned motor pump provided with an auxiliary pump chamber in a communication part of the pump part with a back side of a pump impeller, a partition part separating the pump part and the gas seal chamber has a pump chamber of the pump part. It is configured such that a communication hole communicating with the gas seal chamber is provided.

According to a second aspect of the present invention, in the first aspect, the pump portion side of the flow hole is opened to the back side of the pump impeller near the discharge side of the pump impeller.

According to the first aspect of the present invention, a part of the handled liquid discharged from the pump impeller of the pump portion flows into the gas seal chamber from the back side of the pump impeller via the circulation hole, and is handled from the gas seal chamber. Flows into the rear side of the pump impeller via the auxiliary pump chamber, where it merges with the handling liquid flowing from the flow passage along the rear side of the pump impeller, and returns to the suction side of the pump impeller. As a result, the liquid handled in the gas seal chamber, the peripheral flow path, the auxiliary pump chamber, the back side of the pump impeller 15 and each flow path constantly flows while continuously exchanging the new liquid, and causes polymerization, coagulation, etc. Does not occur.

[0010]

1 and 2 show an embodiment of a gas seal type canned motor pump according to the present invention. FIG. 1 is a front view showing the entirety thereof, a part of which is shown in cross section, and FIG. It is a front sectional view which shows a part. 1 and 2, reference numeral 1 denotes a motor unit, 2 denotes a pump unit disposed below the motor unit, and 3 denotes a gas seal unit provided between the motor unit 1 and the pump unit 2. is there. The motor unit 1 includes a canned motor 10, and a gas seal chamber 12 of the gas seal 3 is formed below the canned motor 10. The pump section 2 is located below the gas seal chamber 12.
Pump casing 14 is hermetically joined and mounted. A pump impeller 15 is rotatably provided in the pump casing 14.

Reference numeral 16 denotes a motor shaft, which penetrates through the motor unit 1, the gas seal chamber 3, and the pump unit 2, and has a rotor of the motor 10 mounted on an upper end and a pump impeller 15 mounted on a lower end. Reference numeral 18 denotes a mechanical seal, which is provided in a penetrating portion where the motor shaft 16 penetrates a partition between the canned motor pump 10 and the gas seal chamber 12. Reference numeral 20 denotes a rotor chamber of the canned motor 10 in which a cooling and lubricating liquid is circulated and supplied.

Reference numeral 22 denotes a pump chamber of the pump section 2, and reference numeral 24 denotes a partition partitioning the gas seal chamber 12 from the pump chamber 22. The partition wall 24, the bottom wall of the gas seal chamber 12 and the upper wall of the pump casing 14 form the gas seal chamber 12 and the pump casing 14.
Is formed. In addition, a sleeve 30 formed by raising the end is integrally formed with the end of the partition wall 24. The shaft 30 is formed inside the sleeve 30, and the motor shaft 16 is inserted therethrough. A minute gap d is held between the sleeve 30 and the motor shaft 16. The sleeve 30 extends to the gas seal chamber 12 along the motor shaft 16, and a plurality of flow holes 32 are formed in the rising base along the circumferential direction, and a plurality of flow holes 34 are similarly formed near the upper end. Has been drilled.

Reference numeral 36 denotes an auxiliary pump chamber, which is formed between the partition wall 24 and the upper wall of the pump casing 14 and in the middle of the shaft penetrating portion 26, and is connected to the inside of the pump casing 14 on the rear side of the pump impeller 15. Are in communication. The auxiliary impeller 4 held by the motor shaft 16 is provided in the auxiliary pump chamber 36.
0 is equipped. A part of the shaft penetration portion 26 from the auxiliary pump chamber 36 to the pump casing 14 is
8 is assumed.

According to the present invention, a flow hole 42 is formed in a partition part for separating the gas seal chamber 12 and the pump casing 14.
The flow hole 42 has an opening on the pump casing 14 side on the back side of the pump impeller 15 near the discharge portion of the pump impeller 15. It is desirable that a plurality of the holes be provided in the circumferential direction. Further, the diameter of the flow hole 42 needs to be appropriately determined according to conditions such as the discharge pressure of the pump impeller 15, the liquid pressure of the liquid handled in the gas seal chamber 12, and the liquid handled in each part.

Next, the operation of the pump will be described. When the supply pressure of the supply liquid to be supplied to the pump is equal to or higher than a predetermined value during the operation of the pump, the supply liquid fills the pump chamber 22 and flows into the gas seal chamber 12 via the circulation hole 42 or the auxiliary pump chamber 36. For example, it reaches the position of the flow hole 34 of the sleeve 30. When the pump operation is started from this state and the motor shaft 16 is rotated, the pump impeller 15 and the auxiliary impeller 40 are also rotated. As a result,
The handling liquid is discharged from the pump impeller 15 and a part of the liquid flows into the back side of the pump impeller 15. Pump impeller 1
A part of the handling liquid that has flowed into the back side of 5 flows into the gas seal chamber 12 via the flow hole 42. The remaining part passes through the back side of the pump impeller 15 and the pump impeller 15
Is returned to the inflow side of the pump impeller 15 from the flow hole 44 formed in the base of the pump impeller 15.

When the handling liquid flows into the gas seal chamber 12, the handling liquid in the gas seal chamber 12 is correspondingly discharged.
2 flows into the auxiliary pump chamber 36 via the shaft penetration portion 26. The handling liquid that has flowed into the auxiliary pump chamber 36 is pressurized by the auxiliary impeller 40 and flows from the circulation hole 38 to the back side of the pump impeller 15. Here, the handling liquid flowing from the auxiliary pump chamber 36 merges with the handling liquid flowing directly from the discharge of the pump impeller 15 along the back side of the pump impeller 15 and returns from the circulation hole 44 to the suction side of the pump impeller 15. I do.

Therefore, the gas seal chamber 12, the shaft penetrating portion 2
6. In any of the auxiliary pump chamber 36, the back side of the pump impeller 15, and each of the flow passages and the flow holes, which are filled with the handled liquid, the handled liquid does not stay and flows constantly. In addition, since the flowing handling liquid is continuously supplied with the handling liquid discharged from the pump impeller 15, all the handling liquids including the handling liquid in the gas seal chamber 12 are constantly replaced. In the present invention, even if the suction pressure and the discharge pressure of the pump impeller 15 fluctuate, the discharge pressure of the auxiliary impeller 40 of the auxiliary pump chamber 36 is hardly affected by the fluctuation, and the flow rate of the handled liquid flowing through the auxiliary pump chamber 36 is reduced. Is regulated to a certain level. Therefore, the liquid level of the handling liquid in the gas seal chamber 12 is stabilized, and the gas sealing effect is maintained.

[0018]

As described above, according to the present invention, the liquid to be handled in the gas seal chamber and in the flow hole communicating the back side of the pump impeller with the auxiliary pump chamber is constantly replenished and exchanged to flow. Therefore, it is possible to reliably prevent polymerization, condensation, and the like from occurring in the liquid handled in the section. Also, if the flow hole is located near the discharge side of the pump impeller,
Since the liquid flows into the outer corner of the gas seal chamber, the entire liquid handled in the gas seal chamber flows evenly and is continuously exchanged with a new liquid, which is more effective.

[Brief description of the drawings]

FIG. 1 is a partially sectional front view showing an entire embodiment of a gas seal type canned motor pump of the present invention.

FIG. 2 is a partial sectional front view showing a main part of an embodiment of the gas seal type canned motor pump of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor part 2 Pump part 3 Gas seal part 10 Canned motor 12 Gas seal room 14 Pump casing 15 Pump impeller 16 Motor shaft 18 Mechanical seal 20 Rotor room 22 Pump room 24 Partition wall 26 Shaft penetration part 30 Sleeve 32 Flow hole 34 Flow hole 36 Auxiliary pump chamber 40 Auxiliary impeller 42 Flow hole 44 Flow path

Claims (2)

[Claims] A gas pump having a pump section provided below a canned motor section via a gas seal chamber, and an auxiliary pump chamber provided in a communication section between the gas seal chamber and a back side of a pump impeller of the pump section. In a sealed type canned motor pump, a gas seal characterized in that a partitioning hole separating the pump section and the gas seal chamber is provided with a communication hole communicating the pump chamber of the pump section and the gas seal chamber. Type canned motor pump. 2. A gas seal type canned motor pump according to claim 1, wherein said pump portion side of said flow hole is opened to the back side of said pump impeller near the discharge side of said pump impeller.