JPS59203896A - Cryogenic liquefied gas pump - Google Patents

Abstract

PURPOSE:To simplify the attaching and detaching of the main body of pump by a method wherein a pump housing is inserted detachably into an inner insulating tank and a seal ring, contacting with the suction port of liquefied gas, is detachably attached to the tip end of the housing. CONSTITUTION:An upper flange of an outer insulating layer 13 and an inner insulating layer 14 is provided with an evacuating pipe and a space between both heat insulating layers 13, 14 is evacuated. The housing 15, accommodating the main body of the pump therein, is inserted detachably into the inner insulating layer 14 while the suction port 8 and the discharging port 9 of the liquefied gas are provided at the tip end of the inner insulating layer 14. The main body of the pump is made by an integral structure, therefore, a seal structure, capable of standing against the pressure difference of the liquid at the suction port 8 and the discharging port 9, is necessitated. Accordingly, a Teflon ring 51 is detachably attached to the tip end of the housing 15 to make the structure capable of compensating the error of installation as well as the dimensional error of working in case of insertion and installation of the housing, accommodating the main body of pump, into the inner insulating layer 14 from the upper part thereof thereby facilitating the adjustment upon the installation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a pump for supplying cryogenic liquefied gas, and particularly to a pump suitable for supplying liquid helium.

[Background of the invention]

Conventional cryogenic liquefied gas pumps have a liquefied gas storage tank or cryostat with a motor installed above it, a drive shaft inserted into the tank, and an impeller connected to its lower end. Ball bearings are used for the bearings. ing.

An example thereof will be explained with reference to FIG. Place motor 4 on the top,
The impeller 1 is rotated via the drive shaft 2. The drive shaft 2 is supported by a general-purpose ball bearing 3. The extremely low temperature liquefied gas is transported through the suction port 8.
The liquid enters the body and is sent out from the discharge port 9. The housing 6 of the pump is formed of a stainless steel pipe and is fixed to the upper flange 5 of the cryostat with a flange, and also fastens the cover 7 of the motor 4. A coil 10 is wound around the housing 6 of the pump, and liquefied gas 11 is passed through it for cooling.

The temperature difference between the motor 4 at normal temperature and the impeller l at extremely low temperature is maintained by the heat transfer resistance caused by the drive shaft 2 and the housing 6I made of stainless steel.

Since the conventional cryogenic liquefied gas pump has such a structure, the drive shaft 2 is long, and cannot rotate at high speed, resulting in a complicated structure.

Furthermore, since the bearing 3 of the impeller 1 is used at extremely low temperatures, it is lubricated by liquefied gas, which has the disadvantage of causing large wear.

On the other hand, a liquefied gas pump using an immersion type motor has been announced, but although this pump has a short drive shaft, the entire body is kept at extremely low temperatures, and ball bearings are used for the bearings, so wear is high. The reliability was low, and the heat generated by the motor resulted in a loss of liquefied gas.

[Purpose of the invention]

An object of the present invention is to solve the drawbacks of conventional cryogenic liquefied gas pumps and to provide a compact and highly reliable cryogenic liquefied gas pump.

[Summary of the invention]

The present invention installs an internal insulation tank in an external insulation tank installed by inserting a liquefied gas storage tank, and also makes the tip of the internal insulation tank protrude from the external insulation tank, so that both insulation tanks can be opened without vacuum. A layer is formed, and a suction port and a discharge port for the liquefied gas are provided at the tip of the internal heat insulation tank, and the blade 14I.

A pop main body consisting of a rotating body consisting of two drive shaft rotors and a driving section consisting of a bearing and a stator is housed in a housing, and the housing is removably inserted into an internal heat insulating tank. The liquefied gas suction port G at the tip
By detachably attaching the seal linog that comes into contact with the pump body, it is possible to simplify the removal and maintenance of the pump body into the internal insulation tank. By installing an exhaust pipe to take out the gas vaporized in the low temperature range from the top of the internal insulation tank, the sensible heat of the vaporized gas is used to reduce heat intrusion into the low temperature range and improve pump efficiency. This is what I did.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. In FIG. 2, an internal heat insulating tank 14 is provided inside the external heat insulating tank 13 with its tip protruding from the external heat insulating tank 13,
Additionally, a suction port 8 and a discharge port 9 are provided within this internal heat insulating tank 14. The pump body has an impeller 1. Drive shaft 2. Motor 4. The bearing part consists of 25 and rows. One part of the external heat insulating tank 13 and the internal heat insulating tank 14 has a flange 17.
The lower end is fixed by a bellows 19 to absorb positional deviation caused by heat shrinkage G. Both insulation tanks ia
, 14 is provided with a radiation sole plate 21, the lower part of which is held by a spacer 22. In addition, laminated heat insulating material is attached to the inner surface of the external heat insulating tank 13 and the outer surface of the internal heat insulating tank 14, and a vacuum exhaust pipe 40 is provided on the flange. Forms a layer and insulates. The housing 15 that houses the pop body is connected to the support tube 16.
1. It is fixed to the upper flange 18 with one twist. The upper flange 18 is provided with exhaust pipes 61 and 62 for venting vaporized gas and a conduit 45 for the lead wire of the motor 4. Heat insulation tank 13
The flange 17 for assembling the housing 1541 containing the pump body is attached to the flange 17 for assembling the heat insulating tank.

The pump body will be explained in detail with reference to FIG. One impeller 1 is attached to the lower end of the drive shaft 2, the rotor shaft of the motor 4 is attached to the upper center, and a disk 4 for a thrust bearing is attached to the upper end. The stator 31 of the motor 4 is installed at a position facing the rotor, and journal bearings 31 and 31 are installed on both upper and lower sides. In this embodiment, a tilting pad type dynamic pressure gas bearing is used, and the tilting pad is supported by the pivot 27''c.A dynamic pressure gas bearing is also used for the thrust bearing. A solid heat insulating material 36 is attached around the drive shaft 2 between the journal bearings U.The pump main body except the impeller 1 is housed in the housing 15.

When the stator 311 of the motor 4 is energized to rotate the pump, liquid helium is sucked in through the suction port 8 and sent out through the discharge port 9 due to the rotation sound of the impeller 1.

By making the pump body into an integrated structure, this suction port 8
A seal structure that can withstand the pressure difference between the fluid and the discharge port 9 is required. In this embodiment, a Teflon ring 51 is removably attached to the tip of the housing 15 for this seal, and the internal heat insulating tank 14 is opened from the upper part of the housing 15 that accommodates the pump body.
The structure is designed to compensate for installation errors during installation and dimensional errors during processing, making it easy to make adjustments during installation.

Further, according to the present structure, maintenance is easy because the seal ring can be easily replaced even if the sealing portion has deteriorated due to deterioration.

Furthermore, the housing 15. located in the room temperature section. From bearing M,
The heat intrusion path from the cryogenic part in contact with liquid helium to the blade l is through the drive shaft 2. The main causes are conduction through the soyaft case 52 and conduction through the outer case and inner case, and the heat introduced by this conduction is reduced to about 1/2 o by using the sensible heat of the helium gas vaporized in the internal heat insulating tank 14. can be reduced to In this embodiment, since the outlet pressure of the impeller 1 and the outlet pressure of the tiff user are different, it is necessary to consider the gas flow for each.

Therefore, the gas venting paths include the gas venting between the drive shaft 2 and the shaft case 52 and the outer case 53.
The two paths for gas venting between the inner case and the inner case are separated. Between the inner gas venting path 55 and the outer gas venting path, the inner gas venting path 55 is a space 37 on the outer periphery of the drive shaft 2. ) Yarnal bearings 24, 25. The space between the rotor and stator 31 of the motor 4 and the inside of the support tube 16 are communicated through the communication hole 32 in the upper part of the housing 15, and the outer gas venting path is connected to the outside of the housing 15 and the internal insulation tank. The outside of the support tube 16 is communicated with the inside of the support tube 16 through a space.

Thus, the helium gas vaporized in the low-temperature parts of the inner gas venting path 55 and the outer gas venting path 56 effectively cools the pump body and housing 15 while rising in both gas venting paths 55 and 56, and then is exhausted. Tube 61. 62
taken out from

In the above-described embodiment, a case has been described in which the gas inside the inner gas venting path 55 and the outer gas venting path are taken out separately, but they can also be combined and taken out from one location.

〔Effect of the invention〕

As described above, the present invention includes an internal insulation tank installed within an external insulation tank inserted and attached to a liquefied gas storage tank, and
The tip of the internal insulation tank protrudes from the external insulation tank to form a vacuum layer between the two insulation tanks, and the liquefied gas suction and discharge ports are provided at the top of the internal insulation tank. The pump body, which is composed of a rotating body consisting of a rotating body and a driving section consisting of a bearing and a stator, is housed inside a housing, and the housing is removably inserted into an internal heat insulating tank, and the liquefied gas is inserted into the tip of the housing. Since the seal ring in contact with the suction port is removably attached, it is possible to simplify the installation and removal of the pump body into the internal insulation tank, as well as maintenance. By installing an exhaust pipe to extract the liquefied gas vaporized in the tank and extracting the gas vaporized in the low temperature range from the top of the internal insulation tank, the pump body and housing can be cooled using the sensible heat of the vaporized gas. Therefore, heat intrusion into the low temperature region can be reduced, and pump efficiency can be improved.

[Brief explanation of the drawing]

@ Figure 1 is a vertical cross-sectional view of a conventional cryogenic liquefied gas pump, Figure 2
The figure is a longitudinal sectional view showing one embodiment of the cryogenic liquefied gas pump according to the present invention, and FIG. 3 is an enlarged detailed view of the pump main body. l... Impeller, 2... Drive shaft, 3...
Ball bearing, 4...Motor, 5...Upper plate, 6.15 Housing, 7...Cover,
8...Suction port, 9...Discharge port, 10...
... Coil, 11 ... Liquefied gas, 13 ...
・Outer heat insulation tank, 14...Inner heat insulation tank, 16...
...Support pipe, 17...Flange, 18...
...Top flange, 19 ... Bellow, 21
...Radiation shield plate, n...Spacer, container...Laminated insulation material, Sae, 25...Journal bearing,...Tilting pad, n
...Pivot, Z...Thrust bearing, 4...Disc, (capital)...Rotor, 3
1...Stator, proverb...Communication hole, 37.
38... Space, 40... Vacuum exhaust pipe, Passage... Lead wire, Decay... Conduit, 51...
・Teflon ring, 52...Shaft case,
Group: outer case, M: inner case, 5
5...Inner gas venting route, %...Outer gas venting route, 61° 1 figure 30

Claims (1)

[Claims]! An internal insulation tank is installed in the external insulation tank installed by inserting the liquefied gas storage tank, and the tip of the internal insulation tank is made to protrude from the external insulation tank to form a vacuum layer between both the insulation tanks, A liquefied gas inlet and outlet are provided at the tip of the internal insulation tank, and an impeller is installed. A pump body consisting of a rotating body consisting of a drive shaft and nine rotors, and a driving section consisting of a bearing and a stator is accommodated in a housing, and the housing is removably inserted into the internal heat insulating layer, and the housing is A cryogenic liquefied gas pump, characterized in that a seal ring in contact with the liquefied gas suction port is detachably attached to the tip of the pump. 2 Cryogenic liquefied gas pump 03 according to claim 1, in which the seal ring is made of Teflon. An internal insulation tank is installed in an external insulation tank inserted and attached to a liquefied gas storage tank, and the internal insulation tank is The tip of the internal heat insulating tank is made to protrude from the external heat insulating tank to form a vacuum layer between the two heat insulating tanks, and the end of the internal heat insulating tank is provided with an inlet and a discharge port for the liquefied gas. A pump body consisting of a rotating body consisting of two drive shaft rotors and a driving section consisting of a bearing and a stator is housed in a housing, and the housing is removably inserted into an internal heat insulating layer, and the internal heat insulating tank is A cryogenic liquefied gas pump characterized in that an exhaust pipe is provided on the upper part of the pump for extracting liquefied gas vaporized within an internal heat insulating layer.