JPH0694877B2 - Gas seal type canned motor pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas-sealed canned motor pump,
The present invention relates to a pump that prevents a pump handling liquid from directly or indirectly coming into contact with a mechanical seal that axially seals a rotor chamber and a gas seal chamber of a canned motor unit to cause a pump failure.

(Prior Art) Generally, the canned motor pump cools the canned motor part and lubricates the bearing by circulating a part of the pump handling liquid to the canned motor part. A gas-sealed canned motor pump is used when a pump handling liquid such as a liquid that easily causes polymerization or gelation and a liquid that is highly corrosive to the bearing causes a failure when circulated to the canned motor unit.

In this gas seal type canned motor pump, as shown in FIG. 4, a canned motor unit 3 is airtightly integrated on the upper side of a pump unit 1 with a gas sealed chamber 2 interposed therebetween. 4 and the gas seal chamber 2 are axially sealed by a mechanical seal 5, and the canned motor unit 3 is driven by the gas 6 sealed in the gas seal chamber 2.
Is shut off from the pump handling liquid 7, and the pressure on the rotor chamber 4 side of the mechanical seal 5 is higher than that on the gas seal chamber 2 side.
And a clear liquid enclosed in the upper pot 8 and the heat exchanger 9.
10 is pressurized by the auxiliary impeller 11 and the canned motor unit 3
As a result, the pump handling liquid 7 is basically prevented from entering the canned motor unit 3.

By the way, in this gas seal type canned motor pump, due to a sudden pressure change at the time of starting the pump, and during the pump operation, due to the disturbance of the pump handling liquid 7 in the gas seal chamber 2 caused by the rotation of the rotary shaft 12. Since the gas 6 in the gas seal chamber 2 is mixed with the pump handling liquid 7 and leaks to the pump unit 1 along the rotary shaft 12, the amount of the gas 6 sealed in the gas seal chamber 2 decreases in a short time. As a result, the liquid level of the pump handling liquid 7 in the gas seal chamber 2 rises, and there is a problem that the pump handling liquid 7 enters the canned motor unit 3, that is, the liquid level rises.

Therefore, the applicant of the present invention has proposed a vertical canned motor pump described in Japanese Utility Model Publication No. 45-8285. This canned motor pump has a structure in which a plurality of baffle plates 13 are radially provided in the gas seal chamber 2 as shown in FIG. Further, a gas seal type canned motor pump described in Japanese Utility Model Publication No. 57-22072 is known. This canned motor pump has a gas seal chamber 2 as shown in FIG.
A sleeve 16 extending toward the gas seal chamber 2 is provided in a shaft penetrating portion 15 provided between the gas seal chamber 2 and a shaft penetrating portion gap 17 formed by the sleeve 16. A structure is adopted in which a plurality of fluid passage holes 18 and 19 are provided in the base portion and the upper end portion of the sleeve 16, respectively.

(Problems to be Solved by the Invention) According to these conventional structures, the baffle plate 13 or the sleeve 16 is provided.
As a result, the pump handling liquid 7 in the gas seal chamber 2 is disturbed due to the rotation of the rotary shaft 12, so that the problem of the liquid level rise in the gas seal chamber 2 is not practical for some pump handling liquids 7. Although it is greatly improved to the extent that it does not cause difficulties, it has not been completely solved yet. That is, the time until the liquid level in the gas seal chamber 2 rises to reach the mechanical seal 5 is drastically increased, but The surface rise is not completely eliminated, and the pump handling liquid 7 may not produce a remarkable effect.

The reason is that the pump handling liquid 7 in the part in the annular space 20 formed between the inner edge of the baffle plate 13 and the outer periphery of the rotary shaft 12 or the shaft formed by the sleeve 16 and the rotary shaft 12 The portion of the pump handling liquid 7 in the penetrating portion gap 17 is still circulated along with the rotating shaft 12, and by this circling, the gas 6 is mixed in the pump handling liquid 7 though it is an extremely small amount, and along the rotating shaft 12. It is presumed that the liquid 6 is leaked to the pump unit 1, and it is confirmed that the liquid level rises extremely rapidly in the case of a highly viscous liquid or a foaming liquid in which the gas 6 is easily entrained or a highly soluble liquid in which the gas 6 is easily dissolved.

Therefore, in order to prevent the pump handling liquid 7 from entering the canned motor portion 3 by suppressing the rise of the liquid level in the gas seal chamber 2 even for a long period of time or for almost any pump handling liquid 7, It is necessary to supply gas 6 to the gas seal chamber 2 from an external gas source as appropriate.

However, even if the liquid level rise in the gas seal chamber 2 is suppressed, the applicant of the present patent application is that the pump handling liquid 7 is a foreign substance-containing liquid such as slurry, or a liquid or a highly viscous liquid that easily causes polymerization or gelation. It was confirmed that the mechanical seal 5 could be abnormally damaged if the pump handling liquid 7 had a strong corrosive property. Even when the liquid level rise in the gas seal chamber 2 is suppressed, the gas seal chamber 2
As a result of the rotation of the rotating shaft 12, the pump handling liquid 7 is scattered upward from the liquid surface of the portion in contact with the rotating shaft 12, but the splash of the pump handling liquid 7 reaches the mechanical seal 5. Lubrication of the mechanical seal 5 by foreign matter such as slurry contained in the droplets or foreign matter formed by polymerization and gelation of these droplets in the mechanical seal 5 part, or by the entry of high-viscosity droplets As a result, the mechanical seal 5 may be damaged and cause a pump failure.

In order to prevent the splash of the pump handling liquid 7 from reaching the mechanical seal 5, as shown by the dotted line in FIG.
It is conceivable to attach a rotating disk 21 close to the lower side of the mechanical seal 5 to the 12, but as the rotation of the rotating disk 21 causes the gas seal chamber 2 to circulate the gas 6, a pump is handled. The finer the droplets of the liquid 7, the more mixed with the circulation of the gas 6 and the greater the fear of reaching the mechanical seal 5. Further, the vaporized gas of the pump handling liquid 7 in the gas seal chamber 2 becomes more mechanical. There is no means for preventing the above from being caused by the vaporized gas of the pump handling liquid 7 such as the case where it is polymerized or gelled in the part, or the mechanical seal is corroded by the vaporized gas.

The present invention has been made in view of the above-mentioned problems. A gas 6 is constantly supplied from an external gas source while the pump is operating or in the pump handling liquid 7, and the gas 6 is passed through a mechanical seal 5 part and then a rotary shaft. By making it flow into the gas seal chamber 2 through the narrow gap 51 between the shaft penetrating portion and 12, it is possible to prevent the liquid level in the gas seal chamber 2 from rising and of course, to scatter upward from the liquid level in the gas seal chamber 2. The mechanical seal 5 prevents the splash of the pump handling liquid 7 and the vaporized gas of the pump handling liquid 7.
The present invention provides a gas-sealed canned motor pump that can prevent the reaching of the gas.

(Means for Solving Problems) A gas-sealed canned motor pump according to the present invention comprises a canned motor part which is airtightly integrated with a gas sealed chamber above a pump part, and a rotor chamber of the canned motor part. In a canned motor pump in which the mechanical seal and the gas seal chamber are axially sealed, a gas receiving chamber is provided between the gas seal chamber and the mechanical seal to shut off the mechanical seal from the gas seal chamber. The receiving chamber and the gas sealing chamber are communicated with each other through a narrow shaft penetrating portion gap whose axial length with respect to the radial length is considerably large, and gas is supplied to the gas receiving chamber during pump operation or in the pump handling liquid. An external gas source for flowing into the gas seal chamber through the shaft penetrating portion gap is connected to the gas receiving chamber.

(Operation) The gas-sealed canned motor pump of the present invention, by constantly supplying gas from an external gas source during pump operation or while the pump handling liquid is present, gas is excessively replenished in the gas seal chamber, so that the gas seal The liquid level rise due to the decrease in the amount of gas in the chamber is blocked, the pump handling liquid does not reach the mechanical seal, and the gas flow from the gas receiving chamber through the narrow shaft penetrating gap into the gas seal chamber The splash of the pump handling liquid and the vaporized gas are prevented from entering the gas receiving chamber and do not reach the mechanical seal. Therefore, the mechanical seal is not damaged due to the pump handling liquid.

(Example) Next, the Example of this invention is described based on drawing.

In FIG. 1 and FIG. 2, reference numeral 70 denotes a canned motor portion 3 which is airtightly integrated with an upper side of a pump portion 1 via a gas sealed chamber 2, and the rotor chamber 4 of the canned motor portion 3 and the gas sealed chamber. 2 is a canned motor pump whose shaft is mechanically sealed by a mechanical seal 5.
An auxiliary impeller 11 is attached to the rotary shaft 12 protruding upward from the rotor so that the pressure on the rotor chamber 4 side of the mechanical seal 5 becomes higher than the pressure on the gas seal chamber 2 side.
The clear liquid 10 enclosed in the rotor chamber 4, the upper pot 8 and the heat exchanger 9 is pressurized by the auxiliary impeller 11,
Further, the mechanical seal 5 is included in the upper bearing 22, the gap 25 between the stator can 23 and the rotor can 24, the lower bearing 26 and the rotor chamber 4, and the mechanical seal 5 provided above the adapter 27 constituting the gas seal chamber 2. Seal liquid chamber 28,
A circulation path is formed through the circulation pipe 29, the heat exchanger 9, the circulation pipe 30, and the upper pot 8 and is circulated to the auxiliary impeller 11 to cool the canned motor portion 3 and lubricate the bearings 22 and 26.

The mechanical seal 5 is arranged with the rotary ring 5a attached to the rotary shaft 12 on the upper side and the fixed ring 5b on the lower side.
The fixed ring 5b is attached and fixed to a fixed ring support 32 attached to a partition wall 31 of an adapter 27 that partitions the gas seal chamber 2 and the seal liquid chamber 28, and the adapter 27 and the pump casing are fixed.
A partition plate 34 for partitioning the gas seal chamber 2 and the pump unit 1 is attached to the joint portion of 33, and the main impeller is attached to the lower end portion of the rotary shaft 12 which penetrates the partition plate 34 and projects to the pump unit 1. 35 are attached.

Further, a plurality of baffle plates 13 projecting upward from the partition plate 34 are radially arranged in the gas seal chamber 2, or a sleeve 16 as shown in FIG. The partition plate is arranged so as to project upward,
34 on the lower surface of 34 and the rear shroud of the main impeller 35
An inner annular space of the orifice 39 constituted by the annular projection 38 of 37 is formed as a balance chamber 40, and the balance chamber 40 communicates with the gas seal chamber 2 at the upper part through a gap 41 of a shaft penetrating portion of the partition plate 34. In the lower part, the main impeller is inserted through the balance hole 42 cut in the rear shroud 37.
The gas seal chamber 2 is communicated with the suction side of 35, that is, the gas seal chamber 2 is communicated with the pump low-pressure portion through the shaft penetrating portion gap 41 of the partition plate 34.

43 and 44 are cooling jackets of the canned motor unit 3 and the upper pot 8, respectively, which are configured so that the cooling water supplied to the heat exchanger 9 via the cooling pipes 45 and 46 sequentially flows, and 47 is a gas seal. A peep window for monitoring the liquid level of the pump handling liquid 7 in the chamber 2 and a peep window for monitoring the liquid amount of the clear liquid 10 circulated in the canned motor unit 3.

The above configuration shows an example of the conventional gas-sealed canned motor pump 70 which is the premise of the present invention. Next, the configuration of the characteristic part of the present invention will be described.

The fixed ring support 32 has its lower end portion extended to the inner diameter side,
A space surrounded by the fixed ring support 32, the rotary shaft 12, and the fixed ring 5b is formed as a gas receiving chamber 49 that shuts off the mechanical seal 5 from the gas seal chamber 2.
The gas seal chamber 2 is provided at the inner diameter of the lower end of the fixed ring support 32.
The sleeve portion 50 extending toward the side is provided, and a narrow shaft penetrating portion gap 51 having a considerably large axial length with respect to the radial length is formed between the sleeve portion 50 and the rotary shaft 12, and the shaft penetrating portion is formed. Due to the gap 51, the gas receiving chamber 49 and the gas sealing chamber 2
And the gas receiving chamber 49 is communicated with the gas receiving chamber 49, the gas passage hole 52 formed in the fixed ring support 32, the internal gas pipe 53 communicated with the gas passage hole 52 by welding, and the adapter 27.
To the outside through a gas inlet 55, which is attached to the side wall of the airtightly and the other end of the internal gas pipe 53 is connected by a union 54, an external gas pipe 56, and a constant flow rate device 57 and a valve 58 provided as necessary. The gas 6 is connected to the gas source 59, that is, the gas 6 is constantly supplied from the external gas source 59 while the pump is operating or in the pump handling liquid 7, and the gas 6 passes through the gas receiving chamber 49 and then narrows. It is configured to flow into the gas seal chamber 2 through the shaft penetrating portion gap 51.

Next, the operation of the embodiment configured as described above will be described.

By constantly supplying the gas 6 from the external gas source 59 to the gas receiving chamber 49 during the pump operation, the gas 6 is replenished to the gas sealing chamber 2 through the shaft penetrating portion gap 51. A slight amount of gas 6 is leaked to the pump portion 1 side and the rise of the liquid level caused by the decrease of the amount of gas 6 in the gas seal chamber 2 is prevented, and the pump handling liquid 7 is replaced by the mechanical seal 5
Of course, since the axial penetration portion gap 51 is narrow and the axial length relative to the radial length is considerably large, the gas passes from the axial penetration portion gap 51 to the gas seal chamber 2.
When the gas is introduced into the gas receiving chamber 49, the velocity of the gas flowing into the gas receiving chamber 49 is increased by the spraying of the pump handling liquid 7 passing through the shaft penetrating portion gap 51 and the vaporized gas of the pump handling liquid 7 being pushed back. As a result, the problem that the mechanical seal 5 is not reached and the mechanical seal 5 is damaged due to the pump handling liquid 7 and a pump failure is solved.

The gas 6 flowing into the gas seal chamber 2 is lowered in the pump handling liquid 7 along the rotary shaft 12, passes through the shaft penetrating gap 41 of the partition plate 34, the balance chamber 40 and the balance hole 42, and then the main impeller. It reaches the suction side of 35 and is discharged to the pump discharge port together with the pump handling liquid 7, but if the supply amount of the gas 6 is excessive, cavitation is generated in the pump part 1 and the supply cost is high. , The maximum supply amount in which the cavitation is not generated, the splash of the pump handling liquid 7 and the vaporized gas of the pump handling liquid 7 are the gas receiving chamber 49
It may be set between the minimum supply amount that can prevent the invasion into, and the closer to the minimum supply amount, the more preferable.

According to the experiment, the diameter of the rotating shaft 12 is 35
mm, the radial length of the shaft penetrating portion gap 51 (one side gap) between the sleeve portion 50 of the fixed ring support 32 and the rotary shaft 12 is 0.8 mm, and the axial length of the shaft penetrating portion gap 51 is 26 mm 2850r.p.
If the pump handling liquid 7 is chlorosilane containing extremely fine-grained slurry, nitrogen gas is supplied as an external gas source 59 at about 200 CC / min so that the gas seal chamber 2
Of course, the gas receiving chamber for the slurry mixed in the vaporized gas of the pump handling liquid 7 is included in the droplets of the pump handling liquid 7 and is extremely fine.
Good results were obtained in which the entry into 49 was prevented and the mechanical seal 5 was prevented from being damaged due to the pump handling liquid 7.

Further, when the gas 6 does not affect the mechanical seal 5 due to the vaporized gas of the pump handling liquid 7, the gas 6 may be constantly supplied from immediately before the pump is started to immediately after the pump is stopped, that is, only during the pump operation. When the mechanical seal 5 is affected by the vaporized gas, it is necessary to continuously supply it even while the pump is stopped, that is, while the pump handling liquid 7 is present.

In the above embodiment, the fixed ring 5b of the mechanical seal 5 is used.
The narrow ring penetrating gap 51 having a considerably large axial length with respect to the radial direction communicating the gas receiving chamber 49 and the gas sealing chamber 2 is formed by the fixed ring support 32 to which is mounted. As shown in FIG. 3, a partition body 60 that covers the bottom of the fixed ring support 32 is attached to the partition wall 31 of the adapter 27, and is surrounded by the partition body 60, the fixed ring support 32, the partition wall 31, and the rotary shaft 12. The space to be filled may be formed as the gas receiving chamber 49. In this case, the sleeve portion 50 is provided at the center of the partition body 60,
A narrow shaft penetrating gap 51 is formed between the sleeve portion 50 and the rotary shaft 12 so that the axial direction with respect to the radial length is considerably large.

Regarding the connection between the external gas source 59 and the gas receiving chamber 49, instead of the internal gas pipe 53, a gas passage hole 61 is formed in the partition wall 31 of the adapter 27 as shown in FIG. It goes without saying that various design changes can be made within the scope of the present invention without being limited to the respective embodiments.

(Effect of the Invention) According to the gas seal type canned motor pump of the present invention,
External gas source while the pump is operating or in the pump handling liquid 7
The gas 6 is constantly supplied from 59, and the gas 6 is supplied to the gas receiving chamber 49.
After that, the gas 6 is excessively replenished to the gas seal chamber 2 by flowing into the gas seal chamber 2 through the narrow shaft penetrating portion gap 51 having a considerably large axial length with respect to the radial length. The pump level liquid 7 is prevented from reaching the mechanical seal 5 because the rise of the liquid level due to the decrease of the amount of gas 6 in the seal chamber 2 is prevented, and, of course, the gas seal is passed from the gas receiving chamber 49 through the narrow shaft penetrating gap 51. The gas flow flowing into the chamber 2 blocks the splash of the pump handling liquid 7 and the vaporized gas from entering the gas receiving chamber 49 and does not reach the mechanical seal 5. Therefore, the mechanical seal is caused by the pump handling liquid 7. The problem of damaging 5 and pump failure is solved, the maintenance cost is greatly reduced, and it is preferable to use it for prevention of danger due to leakage of pump handling liquid 7 and environmental protection. In which the scope of the canned motor pump structure is further expanded.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a gas seal type canned motor pump showing an embodiment of the present invention, FIG. 2 is an enlarged vertical sectional front view of a part of the same, and FIG. 3 is a gas showing another embodiment of the present invention. FIG. 4 is a vertical sectional front view of a conventional gas-sealed canned motor pump, and FIG. 5 is a vertical sectional front view of another conventional gas-sealed canned motor pump. . 1 ... Pump part, 2 ... Gas seal chamber, 3 ... Canned motor part, 4 ... Rotor chamber, 5 ... Mechanical seal,
49 …… Gas receiving chamber, 51 …… Shaft penetration gap, 59 …… External gas source.

Claims (1)

[Claims] 1. A canned motor in which a canned motor part is airtightly integrated on the upper side of a pump part via a gas sealed chamber, and a rotor chamber of the canned motor part and the gas sealed chamber are sealed by a mechanical seal. In the pump, a gas receiving chamber that shuts off the mechanical seal from the gas sealing chamber is provided between the gas sealing chamber and the mechanical seal, and the gas receiving chamber and the gas sealing chamber have an axial length with respect to a radial length. To communicate with each other through a considerably narrow shaft penetrating portion gap to supply gas to the gas receiving chamber during pump operation or in the liquid handling liquid of the pump to flow into the gas seal chamber through the shaft penetrating portion gap. A gas-sealed canned motor pump, wherein an external gas source is connected to the gas receiving chamber.