JP4744857B2 - Submerged pump - Google Patents

Description

  The present invention relates to a submerged pump, and more particularly to a structure of a heat insulating casing in a submerged pump for conveying a low-temperature liquefied gas such as liquid nitrogen, liquid argon, or LNG.

  As a low-temperature liquefaction pump used when transferring low-temperature liquefied gas such as liquid nitrogen, liquid argon, LNG, etc. from a storage tank to another storage tank, or transferring from a tank lorry carrying low-temperature liquefied gas to a storage tank Submerged pumps in which the entire pump is immersed in a low-temperature liquefied gas in a vacuum-insulated casing are often used. Conventional submerged pumps have a structure in which the pump body is housed in a vacuum-insulated casing as described above. Therefore, the entire pump tends to be large, and beside the storage tank for low-temperature liquefied gas. It was often installed (for example, refer to Patent Document 1).

Also, a submerged pump having a structure in which a pump body having a motor part and a pump part is housed in a bottomed cylindrical casing having an upper opening, and the upper opening of the casing is covered with a lid member is known. Yes. The pump body is in a state of being suspended from a lid member, and the casing and the lid member are fastened with bolts and nuts, which are respectively provided with flanges protruding from the upper outer periphery of the casing and the outer periphery of the lid member. The flange structure is detachably coupled (see, for example, Patent Document 2).
JP 2003-130294 A Japanese Patent Laid-Open No. 5-71496 (FIG. 1)

  When the submerged pump as described above is mounted on a tank lorry for low-temperature liquefied gas delivery, not only miniaturization and weight reduction while ensuring sufficient heat insulation are required, but the casing and the lid member are It is necessary to consider workability when attaching and detaching. In particular, in the case of a heat-insulating casing in which the casing has a double structure of an inner tub and an outer tub and a heat insulating layer is provided between the two tubs, the flange projects to the outside of the outer tub and the diameter of the lid member increases and the weight is increased. There is a problem that increases.

  Furthermore, in order to ensure the strength of the enlarged lid member, the lid member and the flange part are made thicker, the number of fastening bolts is increased, and a thick bolt is used to secure the coupling strength. There are problems such as having to. For this reason, the whole submerged pump becomes large and not only increases in weight, but also causes a problem that the heat capacity and heat transfer area also increase. Furthermore, it is also a problem to secure a use space such as a spanner for fastening a large number of bolts and nuts in a limited space of the tank lorry during maintenance of the pump.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a submerged pump having a heat insulating structure that can be reduced in size and weight, reduce the heat transfer area and heat capacity, and is suitable for mounting on a tank truck.

  In order to achieve the above object, the submerged pump according to the present invention has an open upper part composed of a bottomed cylindrical inner tank containing a pump main body and a bottomed cylindrical outer tank covering the periphery of the inner tank. A casing body, a lid member that closes the upper opening of the casing body, a discharge pipe that extends through the lid member from the discharge port of the pump body, and an outside tank that passes through the outer tank In a submerged pump comprising a suction pipe communicating with the inner tub and an outer tub, an upper end of the outer tub is provided on a lower outer peripheral portion of a flange provided on an outer periphery of the upper end of the inner tub. While fixing the edge, planting a planting bolt for fixing the lid member on the upper surface of the flange on the inner peripheral side than the outer tank fixing unit, and inserting the planted bolt into the bolt hole provided in the flange portion on the outer periphery of the lid member, Implanting bolt protruding from the bolt hole By screwing the nut to the bets it is characterized in that removably attached the cover member to the upper portion of the inner tub.

  Furthermore, the submerged pump of the present invention is provided with a step portion for mounting an O-ring that seals between the lower surface of the lid member on the inner periphery of the upper end portion of the inner tank, the discharge port of the pump body, The discharge pipe is directly connected by a pipe flange provided at an end of the discharge pipe.

  According to the submerged pump of the present invention, the upper end edge of the outer tub is fixed to the outer peripheral portion of the lower surface of the flange of the inner tub, and the implantation bolt is planted on the upper surface of the flange on the inner peripheral side. The diameter of the flange can be reduced and the lid member can also be reduced in diameter. Further, by reducing the diameter, the flange portion can be made thin, and the overall weight can be reduced. Furthermore, since the studs are used for joining the flange portions, the fastening operation can be performed from above the lid member, and there is almost no problem in the work space.

  Moreover, the diameter of the flange portion can be further reduced by disposing an O-ring for sealing between the lid member and the inner periphery of the upper end of the inner tank. In addition, by directly connecting the discharge pipe to the discharge port of the pump body, it is possible to reduce the size and weight, reduce the heat transfer area and the heat capacity, reduce the leakage, and reduce the evaporation loss of the low-temperature liquefied gas.

  1 and 2 show an embodiment of a submerged pump according to the present invention. FIG. 1 is a sectional front view of the submerged pump, and FIG. 2 is a partially cutaway plan view.

  This submerged pump has a bottomed cylindrical inner tub 12 that houses a pump main body 11 therein and a bottomed cylindrical outer tub 13 that covers the periphery of the inner tub 12. The casing body 14 has a lid member 15 that closes the upper opening of the casing body 14, and the casing body 14 is a heat insulating casing that is evacuated between the inner tank 12 and the outer tank 13 to form a vacuum heat insulating layer 16. ing. In addition, a fixed leg portion 17 for fixing the submerged pump to the housing or the vehicle body with bolts 17a is provided at the bottom of the casing body 14. In addition, since the pump main body 11 can use a well-known structure, the detailed illustration and description are abbreviate | omitted.

  A suction pipe 19 is provided in the lower part of the peripheral wall of the inner tank 12 so as to penetrate the outer tank 13 through an expansion tube 18 and communicate between the outside of the pump and the inside of the inner tank. A seal-off valve 20 is provided that is used when a vacuum insulation layer 16 is formed by evacuating the tank 12 and the outer tank 13. Further, the discharge pipe 21, the exhaust pipe 22, and the terminal nozzle 23 pass through the lid member 15, and the discharge pipe 21 is directly connected to the pump body 11 by bolts 24 a at the insertion end of the discharge pipe 21. Tube flange 24 is provided.

  A flange 25 for fixing the outer tub 13 and attaching the lid member 15 is provided on the outer periphery of the upper end portion of the inner tub 12. The outer diameter of the flange 25 is set to be equal to or slightly larger than the outer diameter of the outer tub 13, and the upper edge of the outer tub 13 is secured to the outer peripheral portion of the lower surface of the flange 25 using a fixing means such as welding. It is fixed.

  In addition, a predetermined number of implantation bolts 26 are implanted in the circumferential direction at predetermined intervals on the upper surface of the flange 25, and an inner corner of the upper end portion of the inner tub 12 serving as the inner circumferential portion of the flange 25 A step portion 28 for mounting an O-ring (gasket) 27 that seals between the upper surface of the tank 12 and the lower surface of the lid member 15 is provided. The bolt pitch circle diameter in the planting bolt 26 is set between the outer diameter of the inner tub 12 and the inner diameter of the outer tub 13, and the planting bolt 26 is on the inner peripheral side with respect to the fixing portion of the outer tub 13. It is located on the outer peripheral side with respect to the step portion 28. Further, a bolt hole 15 b corresponding to the stud bolt 26 is provided in the flange portion 15 a around the lid member 15.

  The discharge pipe 21, exhaust pipe 22, and terminal nozzle 23 are inserted into the lid member 15 through holes formed in advance and fixed in an airtight state by welding or the like, and the pipe flange 24 of the discharge pipe 21 and the pump The main body 11 is directly fixed by a bolt 24a, and the discharge port of the pump main body 11 and the discharge pipe 21 are connected.

  The lid member 15 integrally having a discharge pipe 21 or the like connected to the lower end of the pump body 11 has the O-ring 27 attached to the step portion 28 of the inner tank 12, and then the implanted bolts 26 are inserted into the respective bolt holes 15b. Then, the nut 29 is screwed and fastened to the implanted bolt 26 protruding from the bolt hole 15b via a spring washer, and the casing body 14 is attached.

  The fastening of the nut 29 can be performed by operating from above the submerged pump, and the workability can be improved as compared with the conventional case where the bolts and nuts above and below the flange are operated simultaneously with a spanner or the like. Moreover, since the outer diameter of the flange 25 of the inner tub 12 and the flange portion 15a of the lid member 15 can be formed to be approximately the same as the outer diameter of the outer tub 13, the flange portion does not protrude greatly from the casing body 14. The submerged pump can be reduced in size and weight. Further, since the cover member 15 can be thinned by reducing the diameter of the flange portion, the cover member 15 itself can be reduced in weight, and the number of bolts for attaching the cover member 15 can be reduced or a small-sized bolt can be used. It becomes.

  Further, by disposing the O-ring 27 at the corner of the inner periphery of the upper end of the inner tub 12, the diameter of the flange 25 can be further reduced as compared with the conventional case where the groove for mounting the O-ring is formed on the upper surface of the flange 25. can do. Furthermore, by connecting the discharge pipe 21 directly to the pump body 11, the structure can be simplified as compared with the case where the pump body 11 and the lid member 15 are connected using a short pipe for connection as in the prior art. Therefore, it is possible to reduce the number of connections that cause leakage.

  By reducing the diameter of the flange portion as described above and simplifying the connection structure of the discharge pipe 21, the submerged pump can be reduced in size and weight without impairing the mechanical strength. Further, the reduction in size and weight reduces the heat capacity and heat transfer area, improves the heat insulation performance, and reduces the evaporation loss of the low-temperature liquefied gas. In particular, by reducing the size and weight and improving the workability when attaching / detaching the lid member, it is possible to reduce the installation space of the tank lorry equipped with the submerged pump and the heavy load, and the lid member 15 in a limited installation space. Can be easily attached and detached.

It is a section front view of the submerged pump which shows one example of the present invention. Similarly, it is a partially cutaway plan view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Pump main body, 12 ... Inner tank, 13 ... Outer tank, 14 ... Casing main body, 15 ... Lid member, 16 ... Vacuum insulation layer, 17 ... Fixed leg part, 18 ... Telescopic pipe, 19 ... Suction pipe, 20 ... Seal Off valve, 21 ... discharge pipe, 22 ... exhaust pipe, 23 ... terminal nozzle, 24 ... pipe flange, 25 ... flange, 26 ... stud bolt, 27 ... O-ring, 28 ... step, 29 ... nut

Claims (3)

  A casing main body having a bottomed cylindrical inner tub in which a pump main body is housed and a bottomed cylindrical outer tub that covers the periphery of the inner tub is opened, and a lid member that closes the upper opening of the casing main body. A discharge pipe that extends through the lid member from the discharge port of the pump body and extends to the outside, and a suction pipe that passes through the outer tank and communicates with the inner tank, the inner tank and the outer tank In the submerged pump in which a heat insulating layer is formed between the upper end edge of the outer tub and the inner peripheral side of the outer tub fixing portion. Planting bolts for fixing the lid member on the upper surface of the flange, inserting the planting bolts into bolt holes provided in the flange portion on the outer periphery of the lid member, and screwing nuts onto the implantation bolts protruding from the bolt holes. The lid member is attached to and detached from the upper part of the inner tank Submerged pump, characterized in that attached to ability.   The submerged pump according to claim 1, wherein a step portion for mounting an O-ring that seals between the lower surface of the lid member is provided on the inner periphery of the upper end portion of the inner tank.   The submerged pump according to claim 1 or 2, wherein the discharge port of the pump body and the discharge pipe are directly connected by a pipe flange provided at an end of the discharge pipe.

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