JPH0765588B2 - Submerged motor type pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to a submerged motor type pump used for pressure-feeding low-temperature liquefied gas such as LNG and LPG, and particularly to taking out instrumentation cables such as vibrometers and thermometers. Regarding the structure.

[Conventional technology]

A conventional instrumentation cable extraction structure for this type of pump will be described with reference to FIG. In the figure, the sequence point 1
Contains a pump 6 and a motor 7 inside. The liquid sucked from the suction pipe 2 of the suction pot 1 and pressurized by the pump 6 is discharged from the discharge pipe 5 of the head cover 20 to the outside. The suction port 1 is generally provided with a gas vent pipe 3 and a liquid vent pipe 4.

In addition, the head cover 20 has a motor cable extraction pipe.
A motor cable 9 for connecting the motor 7 and the motor airtight terminal 8 is passed through the inside of the motor 10. Similarly, the instrumentation cable take-out pipe 14 accommodates the instrumentation cable 13 that connects the vibration meter pick-up 11 and the instrumentation airtight terminal 12. The motor cable take-out pipe 10 and the instrumentation cable take-out pipe 14 are filled with the high-pressure pump handling liquid or the vaporized gas thereof.
0, 14 and the airtight terminals 8, 12 form a pressure boundary with the atmosphere.

Also, since the liquid handled by this pump is a low-temperature liquid such as LNG, LPG, etc., the pump pot 1 and the head cover 20
Is kept cold by a thick-walled cold insulator that can be removed during maintenance. At the time of pump maintenance, the suction pot 1 is stored in the installed state, the head cover 20, the motor 7, and the pump 6 are integrally lifted by a crane or the like and disassembled at another place for maintenance.

Related to this type of pump, there are, for example, Japanese Patent Publication No. 58-25876 and Japanese Utility Model Publication No. 56-9118.

[Problems to be Solved by the Invention]

In the above conventional technique, the thin and long instrumentation cable extraction pipe 14 is
There was a risk of damage due to improper handling during pump maintenance or vibration during operation. Instrumentation cable extraction tube
If 14 is damaged, liquefied gas handled by the pump such as LNG and LPG may flow out to cause an explosion accident, and there was a problem in reliability of the pump. Further, if there are many pipes attached to the head cover 20, there is a problem in that the number of divisions of the cold insulating material covering only the head cover provided only for the liquefied gas pump increases and the maintainability deteriorates.

An object of the present invention is to obtain a submerged motor type pump which has a low risk of damaging the instrumentation cable take-out pipe and a risk of leakage of the liquid handled by the pump to the outside and is also excellent in maintainability.

[Means for Solving the Problems]

In order to achieve the above object, a configuration of a submerged motor type pump according to the present invention is a submerged motor type pump for pumping a liquid such as a liquefied gas, and a motor inside the pump and an airtight terminal provided outside the pump. A motor cable for connecting the motor cable to the inside is provided with a high-pressure pipe for extraction, an instrumentation pickup provided inside the pump and an airtight terminal provided outside the pump, and an instrumentation cable for transmitting an electric signal. In the submerged moat pump, an instrumentation cable protection tube is provided in the high-pressure tube for taking out the motor cable, the inner and outer surfaces of which are not subjected to pressure, and both ends or one end of which is opened in the high-pressure tube for taking out the motor cable. The instrumentation cable is laid inside the pipe.

A magnetic metal material is used for the instrumentation cable protection tube.

[Action]

According to the present invention, by eliminating the long and small instrumentation cable take-out pipe, laying the instrumentation cable in the large-diameter motor cable take-out high-pressure pipe and storing the instrumentation cable in the instrumentation cable protection pipe As a result, it is possible to eliminate the conventional instrument cable take-out pipe, which is easily damaged, and thus reduce the risk of leakage of the liquid handled by the pump to the outside. Also, since there is no instrumentation cable extraction tube,
The number of divisions of the heat insulating material covering the head cover is reduced, and the maintainability is improved. Further, according to the present invention, by providing the instrumentation cable protection tube, it is possible to prevent noise from being mixed into the instrumentation line by the motor cable and prevent entanglement between the instrumentation cable and the motor cable.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1, 3, and 4. In this embodiment, a small diameter instrumentation cable protection tube 15 which is a non-pressure resistant member is provided in a high pressure tube 10 for taking out a large diameter motor cable which is a pressure resistant member, and an instrumentation cable is laid inside the protection tube 15. The protective tube 15 is provided to separate the motor cable 9 and the instrumentation cable 13 from each other to suppress electrostatic induction noise generation in the instrumentation cable, and to prevent damage and breakage due to entanglement of both cables. is there.
In this embodiment, both ends or one end of the protective tube 15 are opened, and the protective tube 15 is a non-pressure resistant member that does not receive pressure.

If a pressure difference is provided between the inside of the high-voltage pipe 10 for taking out the motor cable and the inside of the taking-out cable for taking out the instrumentation cable, and the pipe receives internal pressure or external pressure, a seal must be provided at the end of the protective gap 15. When the vibration meter pick-up 11 is not provided in the high-voltage motor chamber but is provided in another low-voltage part or high-voltage part, a seal is provided on the instrumentation cable 13 to guide it into the motor chamber, and the structure is laid inside the protective tube 15. do it. Alternatively, the motor cable 9 may be provided with a seal, and the seal may be introduced into the instrumentation cable laying room, and then the structure described above may be employed.

Instrument airtight terminal 12 in the middle of motor cable take-out tube 10.
A flange 10a for attaching the instrumentation cable 13 is attached, and the end of the instrumentation cable 13 is connected to the airtight terminal 12. The motor cable 9 is connected and fixed to the motor airtight terminal 8 as in the conventional case. In the present embodiment, the motor and the airtight terminal for instrumentation are separately provided, but both airtight terminals 8 and 12 are provided.
May be integrated.

The material of the protective tube 15 may be stainless steel, low carbon steel, aluminum alloy, or the like. Instrumentation cable 13
In order to reduce or prevent the electromagnetic induction noise from entering the motor cable 9, it is desirable to use a magnetic material. However, a non-magnetic material can be used when other countermeasures against electromagnetic induction noise are taken, such as using the instrumentation cable as a shield wire, or when the electromagnetic induction noise is of a magnitude that does not pose a problem in instrumentation.

In this embodiment, stainless steel is used for the high-voltage tube 10 for taking out the motor cable and low carbon steel is used for the protective tube 15, and the protective tube 15 is taken out by the support band 16 as shown in FIGS. 3 and 4. The structure is fixed to the high-pressure pipe 10. Supporting band 16
Therefore, the reason for fixing to the high pressure pipe 10 is that the low temperature liquefied gas, which is the liquid handled by the pump, rises and falls in the motor cable take-out pipe 10 when the pump is stopped and started. This is to prevent excessive thermal stress from being generated in the welded portion due to the difference.

As described above, according to the present embodiment, the thin and long instrumentation cable take-out pipe forming the pressure boundary with the atmosphere can be eliminated, so that the reliability against leakage can be improved.
Further, in the conventional structure, the instrumentation cable take-out pipe 14 is constituted by pressure-resistant welding at two or more places, but in the present embodiment, as shown in FIG. Since the instrumentation cable 13 can be taken out,
The reliability against leakage can be improved. Further, since the structure of the head cover part is simplified, cold insulation work is facilitated.
Furthermore, the instrumentation cable take-out pipe will not be damaged due to work failure during lifting, overturning, or transportation during maintenance.

Further, according to this embodiment, since the motor and the instrumentation cable take-out pipe can be integrated into one unit, the conventional instrumentation cable take-out pipe having a small diameter and a long length can be eliminated. As a result, the risk of damaging the instrumentation cable extraction pipe is eliminated, and the risk of leakage of the pump handling liquid to the outside can be reduced. Further, since the number of pipes attached to the head cover is reduced, the number of divided head cover cold insulators to be attached and detached for each pump maintenance is reduced, and the maintainability is also improved. When the motor cable and the instrumentation cable are simply laid in the same pipe, noise is mixed in the instrumentation cable due to the power cable. This noise mainly has the power supply frequency, and this is almost the same as the pump vibration frequency to be measured by the vibrometer, or it is an integer culture or a fraction of an integer. Surveillance may be hindered. In addition, if the insulation of the motor cable should be destroyed, the insulation of the instrumentation cable may also be destroyed and the vibration meter amplifier and the pickup may be destroyed.

In the present embodiment, the protection tube 15 made of a conductive material such as metal is used, and both cables of the motor cable 9 and the instrumentation cable 13 are separately arranged in the high pressure tube 10 related to the same take-out tube. Solving the problem. Further, unlike the other pumps, in the case of the submerged motor type pump for liquefied gas, the motor and the vibrometer pick-up are provided at relatively close positions, and the pressures of the mounting portions of both are almost equal, so Thus, laying both cables in the same pipe also has the effect of simplifying the electrical wiring system. Further, by providing the protection tube, it is possible to suppress electrostatic induction noise that enters the instrumentation cable. Further, in the unlikely event that the insulation of the motor cable is broken, the protective tube 15 is grounded and the instrumentation cable 13 is not damaged. Furthermore, if a magnetic metal material is used as the protective tube 15, electromagnetic induction noise can be prevented and noise countermeasures can be taken completely. As a material for the protective tube, a polymer material having no conductivity is not preferable because it has a small electrostatic induction noise shielding effect and a grounding effect.

〔The invention's effect〕

According to the present invention, it is possible to obtain a submerged motor type pump which is capable of reducing the risk of damage to the instrumentation cable extraction pipe and the risk of leakage of the liquid handled by the pump to the outside, as well as having excellent maintainability. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a submerged motor type pump according to an embodiment of the present invention, FIG. 2 is a vertical sectional view showing a conventional submerged motor type pump, and FIG. 3 is II of FIG. -II
FIG. 4 is a sectional view taken along the line, and is a sectional view of the high-pressure pipe portion for taking out the motor cable of FIG. 1 ... Succession point, 6 ... Pump, 7 ... Submerged motor, 8 ... Motor airtight terminal, 9 ... Motor cable, 10 ... High-voltage pipe for extracting motor cable, 11 ...
… Vibration meter pick-up, 12 …… Instrumentation airtight terminal, 13 …… Instrumentation cable, 14 …… Instrumentation cable extraction tube, 20 …… Head cover.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akihisa Okada, 603 Jinritsu-cho, Tsuchiura-shi, Ibaraki Hiritsu Plant Co., Ltd. Tsuchiura Plant (72) Inventor Takahiro Watanabe 4087, Kachimachi-cho, Tsuchiura-shi, Ibaraki Hitachi Techno Engineering Co., Ltd. (56) Reference JP-A-57-73890 (JP, A) JP-A-59-582 (JP, A)

Claims (2)

[Claims] 1. A high-pressure pipe for extracting a motor cable, in which a motor cable for connecting a motor inside the pump and an airtight terminal provided outside the pump in a submerged motor type pump for pumping a liquid such as liquefied gas is passed inside. In a submerged motor type pump comprising an instrumentation cable for transmitting an electric signal by connecting an instrumentation pickup provided in the pump and an airtight terminal provided outside the pump, in the high-pressure pipe for extracting the motor cable, A submerged, characterized in that an instrumentation cable protection tube, which is not subjected to pressure on its inner and outer surfaces and whose both ends or one end is opened in the high-pressure tube for taking out the motor cable, is provided with the instrumentation cable inside the protection tube. Motor type pump. 2. The submerged motor type pump according to claim 1, wherein the instrumentation cable protection tube is made of a magnetic metal material.