JPH019096Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a submerged pump installed in a tank that stores liquefied gas such as LPG or LNG, and particularly relates to the structure of an airtight terminal used in this submerged pump.

Generally, this type of submerged pump is disposed at the bottom of a tank, so a means is provided to allow it to be pulled up from inside the tank at any time when maintenance or inspection of the pump is performed. In addition, a canned motor is adopted as a means of driving this type of pump, and is integrated with the pump structure, circulating a part of the pump handling liquid to the canned motor, lubricating the bearings, and absorbing the heat generated by the canned motor into the circulating fluid. The canned motor is cooled down. Therefore, in a submerged pump configured in this way, a conductive cable is introduced into the tank via a terminal box provided outside the tank, and is then connected airtightly or liquidtightly to the motor stator of the canned motor from inside the tank. There is a need to.

FIG. 1 shows a typical configuration example of the above-mentioned submersible pump. Reference numeral 10 indicates a liquid storage tank, and an opening 12 provided at the top of the tank 10 allows a canned motor pump structure. A motor pump unit 14 consisting of a motor pump unit 14 is inserted therein. In this case, the discharge pipe 16 of the motor pump unit 14 is
4, and a flange portion 18 provided at the upper end portion is fixed to the opening portion 12 of the tank 10. Further, an external conduit 20 that communicates with the inside of the tank 10 extends from a part of the flange portion 18 and is connected to a terminal box 22 . Therefore, the conductive cable 24 led out from the terminal box 22 is introduced into the tank 10 via the external conduit 20, and is further connected to the motor stator winding provided in a part of the external casing of the motor pump unit 14. Connect to terminal 26.

However, in the submerged pump configured as described above, in order to arrange the conductive cable 24 inside the tank 10, the motor pump unit 14 and the terminal box 22 are provided with terminals 26 and 28 that are configured airtightly or liquidtightly, respectively. electrical connections are made. However, in tanks that store liquefied gases such as LNG and LPG, the temperature inside the tank changes from extremely low temperatures to high temperatures. In order to easily maintain reliable airtightness over a long period of time, maintenance and inspection work must be performed frequently and parts replaced each time.

Therefore, the present inventors conducted various studies in order to overcome the problems of the airtight terminal for connecting the conductive cable in the conventional submerged pump mentioned above, and as a result, they installed a conductor in the terminal insertion hole provided in the terminal block. A sealing metal in which a held ceramic terminal is inserted, and both edges are bent into a hook shape between the ceramic terminal and one opening edge of the terminal block, and between one end of the ceramic terminal and the conductor. It has been found that by fixing with a ring by means such as brazing or welding, both sides of the terminal block can be hermetically isolated and the above-mentioned problems can be solved.

Accordingly, an object of the present invention is to provide an airtight terminal for a submerged pump that has a simple structure, has excellent strength, and is easy to handle and requires almost no maintenance.

In order to achieve the above object, in the present invention, a motor pump unit is disposed inside a liquid storage tank, a conductive cable is led into the tank from a terminal box communicating with the inside of the tank, and this conductive cable is connected inside the tank. In a submerged pump connected to an airtight terminal provided on the external casing of a motor pump unit disposed in The ceramic terminal is airtightly fixed to the terminal block and the conductor through sealing metal rings.

Next, embodiments of the airtight terminal for a submerged pump according to the present invention will be described in detail below with reference to the accompanying drawings. Note that for convenience of explanation, common components will be described with the same reference numerals.

FIG. 2 is a sectional view of essential parts showing an embodiment of the airtight terminal according to the present invention. That is, in FIG. 2, reference numeral 30 indicates a terminal block, and this terminal block 30
A ceramic terminal 36 having a conductor 34 passed therethrough is inserted into a terminal insertion hole 32 formed in the terminal hole 32 . However, the ceramic terminal 36 configured and arranged in this way
A sealing metal ring 38 having both edges bent into a hook shape is airtightly fixed between the opening edge of the terminal insertion hole 32 formed in the terminal block 30. Further, at one end of the ceramic terminal 36, a sealing metal ring 40 having both edges bent into a hook shape is hermetically fixed between the penetrating conductor 34 and the ceramic terminal 36. In this case, in the embodiment shown in FIG. 2, both edges of the sealing metal ring 38 are bent in the same direction,
Airtightness is maintained by welding and fixing one side edge to the opening edge of the terminal block 30 and fixing the other side edge to the ceramic terminal 36 by brazing. The other sealing metal ring 40 has both edges bent in opposite directions, and one edge is brazed to the outer peripheral edge of the ceramic terminal 36 and the other edge is brazed to the conductor 34. Maintain airtightness by attaching and fixing. As a result, the terminal block 30
Both sides are hermetically sealed. Note that conductive cables 42 and 44 are connected to both ends of the conductor 34, respectively.

FIG. 3 shows a modification of the airtight terminal shown in FIG. 2, in which both edges of the sealing metal ring 38 are bent in opposite directions, and the fixing method by welding and brazing is the same as in the embodiment described above. is the same as
In FIG. 3, a nut 46 for supporting the ceramic terminal 36 from below is screwed onto the conductor 34.

FIG. 4 shows a modification of the airtight terminal shown in FIG. 3. That is, in this example, a stepped portion 48 is provided on the lower outer peripheral surface of the ceramic terminal 36,
This stepped portion 48 is engaged with a stepped portion 50 provided in a part of the terminal insertion hole 32 of the terminal block 30 to be stably held. With this configuration, the strength of the ceramic terminal 36 against external forces in the vertical and horizontal directions is sufficiently strengthened.

5 and 6 show another embodiment of the hermetic terminal according to the present invention. That is, when the ceramic terminal 36 is configured to increase its strength against external forces as described above, for example, when used in an environment lower than room temperature, the difference in linear expansion coefficient between the ceramic terminal 36 and the terminal block 30 causes There is a drawback that thermal stress adversely affects strength. Therefore,
In the embodiment shown in FIG. 5, in the configuration shown in FIG.
A predetermined gap is provided between the step portion 50 of the terminal block 30 and a predetermined gap is provided between the inner circumferential surface of the step portion 50 of the terminal block 30 and the outer circumferential surface of the ceramic terminal 36. be. As a result, the ceramic terminal 36 is not affected by the linear expansion of the terminal block 30 at all.

Alternatively, as shown in FIG. 6, in the configuration shown in FIG.
A spacer 52 made of an elastic material or a material with a large coefficient of linear expansion is interposed in the gap provided between the step part 50 of the terminal block 30 and the step part 50 of the terminal block 30. With this configuration as well, it is possible to expect the same actions and effects as in the embodiments described above.

As is clear from the various embodiments described above, the airtight terminal according to the present invention can maintain excellent airtightness with a simple structure, so it can be used, for example, in the motor pump unit 14 of the submerged pump shown in FIG. It can be suitably applied as the terminal 26 directly connected to the terminal 26 and the terminal 28 of the terminal box 22 provided outside. In addition, the airtight terminal according to the present invention has an excellent structure in terms of strength and requires almost no maintenance and inspection work, so it is particularly suitable for use as a submerged pump installed in a liquid storage tank. be.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various improvements and changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the configuration of a conventional submerged pump, Fig. 2 is a sectional view of essential parts showing an embodiment of an airtight terminal for a submerged pump according to the present invention, and Figs. FIG. 2 is a sectional view of a main part showing a modified example of the airtight terminal shown in FIG. 2, FIG. 5 is a sectional view of a main part showing another embodiment of the airtight terminal according to the present invention, and FIG. FIG. 7 is a sectional view of a main part showing still another embodiment. 10...Liquid storage tank, 12...Opening, 1
4...Motor pump unit, 16...Discharge piping, 18...Flange section, 20...External conduit, 2
2...Terminal box, 24...Conductive cable, 26,2
8...Terminal, 30...Terminal block, 32...Terminal insertion hole, 34...Conductor, 36...Ceramic terminal,
38, 40... Metal ring for sealing, 42, 44...
...Conductive cable, 46...Nut, 48...Step part, 50...Step part, 52...Spacer.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A motor pump unit is disposed within a liquid storage tank, a conductive cable is led into the tank from a terminal box communicating with the inside of the tank, and this conductive cable is disposed within the tank. In the submerged pump, the airtight terminal is connected to an airtight terminal provided on the external casing of a motor pump unit, and the airtight terminal is formed by inserting a ceramic terminal having a conductor passed through and held through a terminal insertion hole drilled in the terminal block. ,
An airtight terminal for a submerged pump, characterized in that the ceramic terminal is airtightly fixed to a terminal block and a conductor through sealing metal rings. (2) In the airtight terminal described in claim 1 of the utility model registration claim, the sealing metal ring has both edges bent in a hook shape in the same direction or in opposite directions,
An airtight terminal for a submerged pump consisting of a ceramic terminal and a conductor that are brazed and fixed to the terminal block by welding. (3) An airtight terminal for a submerged pump, in which the lower end of the ceramic terminal is supported by a nut screwed onto a conductor, in the airtight terminal according to claim 1 or 2 of the utility model registration claim. (4) In the airtight terminal according to claim 1 or 2 of the utility model registration claim, a stepped portion is provided on the lower outer peripheral surface of the ceramic terminal, and this stepped portion is configured to engage with a stepped portion provided on the terminal block. Airtight terminal for submerged pump consisting of: (5) The airtight terminal for a submerged pump according to claim 4 of the utility model registration, which is configured to have a predetermined gap between the stepped portion of the ceramic terminal and the stepped portion of the terminal block. (6) The airtight terminal for a submerged pump according to claim 5 of the utility model registration, wherein a spacer made of an elastic material or a material with a large coefficient of linear expansion is interposed in the gap. (7) An airtight terminal for a submerged pump, in which the terminal in the terminal box is constituted by an airtight terminal in the airtight terminal according to claim 1 of the utility model registration claim.