KR100753053B1 - Structure for installation and method for maintenance for refrigerating machine - Google Patents

Abstract

The unit combined with the freezer is kept at a cryogenic state and, in addition, maintenance can be performed easily without a shield unit.

The vacuum container is a sleeve for accommodating the first and second stage cooling cylinders C1 and C2 in a state insulated from the vacuum region in the vacuum chamber, and the opening is provided at a position close to the wall of the vacuum container. The sleeve 2 which has it is installed. In the first stage and second stage cooling cylinders, part of them is in surface contact with the sleeve. In the first stage cooling cylinder, the motor portion M-2 is mounted in a position corresponding to the opening of the sleeve, and the ordinary portion 41-2 is inserted into the sleeve so as to seal the space in the sleeve. Install the flange 41 having a. The O-Ring 42 was sealed between the ordinary part and the inner wall of the sleeve opposite thereto, leaving the first and second stage cooling cylinders and detaching the motor drive and the displacer so that they could be replaced with a new displacer.

Refrigerating equipment, vacuum containers, flanges, shield units, sleeves

Description

Mounting structure and maintenance method of refrigerator {Structure for installation and method for maintenance for refrigerating machine}

1 is a structural diagram showing an embodiment of the present invention with respect to a GM refrigerator.

FIG. 2 is a diagram showing a state in which the motor drive unit and the displacer in the GM refrigerator shown in FIG. 1 are removed to be replaced.

FIG. 3 is a view for explaining the operation of removing a freezing film or frost performed on the cooling cylinder after removing the motor driving unit and the displayer shown in FIG. 2.

4 is a view for explaining the operation of mounting a new motor driving unit and a displacer after the freezing film or frost shown in FIG. 3 is removed.

5 is a view for explaining the structure of a conventional GM refrigerator.

FIG. 6 is a view for explaining a state in which the GM refrigerator of FIG. 5 is mounted in a vacuum container.

Explanation of symbols on the main parts of the drawings

C1, C2: 1st stage, 2nd stage cooling cylinder

D1, D2: Displacer

F1, F2: 1st stage, 2nd stage cooling flange                 

H1, H2: 1st, 2nd stage cold bed

M: motor drive part

R: GM Refrigerator

1: vacuum container

2: sleeve

3a, 3b: indium sheet

4, 21, 41: flange

6: heat shield container

41-1: Plate member

41-2: Normal part

41-3, 42: O-Ring

44: guide pin

45: spring washer

46: connector

The present invention relates to a mounting structure for a vacuum vessel of a refrigerator in a cryostat of a refrigerator and a maintenance method of the refrigerator.

Recently, a GM refrigerator R as shown in FIG. 5 is used instead of liquid helium as a cooling means of a cryostat (cryogenic vacuum vessel). The structure of the GM refrigerator (R) is largely divided into a motor driving unit (M), a plurality of stages (two stages) of cooling cylinders (C1, C2), and a heat storage body, and by the motor driving unit (M). It consists of the displacer D1, D2 which reciprocates in cylinder C1, C2. A first stage cold head H1 and a second stage cold head H2 are formed at a lower end of the first stage cooling cylinder C1 and a lower stage of the second stage cooling cylinder C2, respectively. On the upper opening edge of the first stage cooling cylinder C1, a flange 4 is provided for mounting the motor driving unit M and for mounting the vacuum vessel described later. The displacers D1 and D2 are inserted into the first and second stage cooling cylinders C1 and C2 through the opening of the flange 4.

In the GM refrigerator R having the two-stage cold heads H1 and H2, the cryogenic temperature is 70 to 40K in the first stage cold head H1 and 20 to 4K in the second stage cold head H2. The to-be-cooled object is cooled to predetermined temperature by the cold head of each stage.

Maintenance of GM Chiller R is necessary when GM Chiller R is used for a long time (approximately 10,000 hours of operation) for cooling superconducting magnets or general cryostats. Normal maintenance is the replacement and inspection of parts at all times in motion. In the case of performing this maintenance work, it is necessary to pull out and remove the motor drive part M and the displacer D1 and D2 connected to it from the 1st and 2nd stage cooling cylinders C1 and C2. .

However, when the displacers D1 and D2 cooled to low temperature are removed from the first and second stage cooling cylinders C1 and C2 in the air, the first and second stage cooling cylinders C1 and C2 are instantaneously extracted. Moisture in the air adheres to the inner surface of the c) to form a freezing film to cover the inner surfaces of the first and second stage cooling cylinders C1 and C2. The attached freezing film can be temporarily removed by a dryer or the like. However, since the first and second stage cooling cylinders C1 and C2 continue to cool in the cryogenic vacuum vessel, an ice film is formed on the inner surfaces of the first and second stage cooling cylinders C1 and C2 again. As a result, maintenance work becomes impossible.

Therefore, the operation had to be performed after stopping the apparatus and returning the whole apparatus to normal temperature. After the device is stopped, the time required for the device to return to room temperature depends on the heat capacity of the object to be cooled, but it may take as long as 1 day or as long as 6 days, during which time the device remains idle. Will be. On the other hand, the time required for maintenance of the refrigerator is about 3 hours per unit.

In the case of maintenance of a GM refrigerator mounted on a production facility or the like, it is not preferable to stop the production line for a long time. Therefore, the GM refrigerator which needs maintenance needs to replace the GM refrigerator set including the first and second stage cooling cylinders C1 and C2 as it is without maintenance. The thing of the structure shown in FIG. 6 is proposed.

That is, in the top plate 11 of the vacuum container 1, a sleeve 2 having an opening portion is provided on the upper side for resolving the vacuum region in the vacuum container 1. Then, the first stage and second stage cooling cylinders C1 and C2 of the GM refrigerator R are inserted from the upper opening of the sleeve 2, and the first stage and second stage cooling cylinders C1 and C2 are vacuumed. The GM refrigerator (R) is installed in a state insulated from the vacuum region in the container (1).                         

The sleeve 2 has a first stage sleeve 2a provided with a first stage cooling flange F1 at a lower end thereof, an upper end connected to the first stage cooling flange F1, and a second stage cooling flange ( F2) is provided with the 2nd stage sleeve 2b. A flange F3 for hermetically attaching a bolt to the top plate 11 of the vacuum container 1 is welded to the edge of the opening of the first end sleeve 2a. As mentioned above, the flange 4 is also bolted to the top plate 11 of the vacuum vessel 1. The top plate portion of the heat shield container 6 is mounted to the first stage cooling flange F1 so as to be capable of heat transfer. In addition, a coolant such as a superconducting magnet is in contact with the second stage cooling flange F2 so as to be capable of heat transfer.

6, the contact surface of the first stage cold head H1 and the first stage cooling flange F1 of the GM refrigerator R, and the second stage cold head H2 and the second stage cooling flange F2. In order to increase the thermal contact of these contact surfaces, indium sheets 3a and 3b each having a thickness of about 0.5 to 1 mm are inserted. Hereinafter, these contact surfaces are called thermal contact interfaces.

In FIG. 6, the sleeve 2 is shown as a single line ignoring its thickness, and a thermal contact interface is provided between the inner surface of the sleeve 2 and the outer surfaces of the first and second stage cooling cylinders C1 and C2. Except for spaces. The thermal contact interface is a surface perpendicular to the extending direction of the first and second stage cooling cylinders C1 and C2.

By the way, by using the sleeve 2 as described above, it is possible to completely replace the GM refrigerator single set without returning the apparatus to room temperature. However, when the GM refrigerator single product including the first stage and the second stage cooling cylinders C1 and C2 is removed from the sleeve 2 and replaced as it is, it is exposed to the atmosphere eventually. In this case, air is mixed into the cryogenic sleeve 2, and a freezing film formed by air or the like is formed at the thermal contact interface of the cold head of the GM refrigerator to be newly inserted and the sleeve 2, and the thermal contact (thermal conductivity performance) ) Decreases.

The problem of the maintenance method using the said sleeve 2 is as follows.

(1) A shield unit is required to prevent the incorporation of air, etc., during replacement.

② Replacement is the work in the shield unit.

③ The indium sheet interposed at the thermal contact interface is quenched and hardened, and the flexibility in cold head contact is lost.

(4) When the first stage and second stage cooling cylinders (C1, C2) of the GM refrigerator are inclined and inserted at the time of replacement, the contact area at the thermal contact interface is reduced.

⑤ It is impossible to correct even if the exchange is defective.

⑥ If there are many replacement work procedures, work skill is required.

Then, the object of this invention is to make it easy to perform maintenance work, without a shield unit, in the state which the apparatus which combined a refrigerator is cryogenically.

The present invention relates to a refrigerator which is inserted into a vacuum container in which a cooled object is to be cooled and performs cooling, comprising: a motor driver, a displacer mounted on the motor driver and driven by the motor driver; A mounting structure for mounting a refrigerator including a cylinder in the vacuum container, wherein the vacuum container is a sleeve for accommodating the cylinder in a state in which it is separated from the vacuum region in the vacuum container. A sleeve having an opening is provided at a position close to the wall of the container, and a portion of the cylinder is in surface contact with the sleeve, and the cylinder is located at a position corresponding to the opening of the sleeve. In order to seal the space in the sleeve at the same time the motor drive unit is mounted in the inserted state A first flange having a normal portion penetrating therein is provided to seal the O-ring between the normal portion and the inner wall of the sleeve opposite thereto, leaving the cylinder and the motor driving portion; And dismounting the displacer so that it can be replaced with a new displacer.

In this mounting structure, the opening of the sleeve is provided with a second flange facing the outer periphery of the first flange, and the bolt is mounted between the first flange and the second flange with bolts. Each of the first flange and the second flange is characterized in that at least one guide pin is provided for regulating the inclination of the cylinder when the normal part is inserted into the sleeve.

In this mounting structure, the said bolt penetrates in the state which made the said 2nd flange loosely inserted, and is a spring washer between the head part of this bolt and the 2nd flange which this head part opposes. It is characterized by interposing (spring washer).

According to the present invention, furthermore, as the maintenance method of the refrigerator by the mounting structure of the refrigerator described above, the surface contact between a part of the cylinder and the sleeve is performed on a surface perpendicular to the extending direction of the cylinder, The motor driving part is detached from the first flange to be pulled out of the cylinder together with the displacer, and when the extraction is carried out, the first flange and the second flange are loosened and loosened so that the normal part is several mm. The surface contact is released by inserting a combination of a new motor driving part and a displacer into the cylinder through the first flange, and then the normal part is pushed back to its original position and then the part of the cylinder and the The maintenance method of the refrigerator characterized by the surface contact of the sleeve It is.

<Example>

With reference to FIG. 1, embodiment of the mounting structure of the refrigerator which concerns on this invention is described. This embodiment is a case where it applies to GM refrigerator. The characteristic of this embodiment is the flange 41 provided in the flange 21 (2nd flange) in the opening part of the sleeve 2, and the upper opening edge of the 1st stage cooling cylinder C1 of the location corresponding to this. (First flange), and their peripheral structures. The structure of the other parts is substantially the same as that described in Figs. 5 and 6, and therefore the same reference numerals are added to the same parts.

As described above, the GM refrigerator is inserted into a vacuum vessel (not shown) in which the object to be cooled is stored to perform cooling, and is mounted on the motor driving unit M and the motor driving unit M, and mounted on the motor driving unit M. A displacer (not shown) driven by the cylinder, and a cylinder that reciprocally receives the displacer. The cylinder consists of 1st stage and 2nd stage cooling cylinders C1 and C2.                     

The first stage cold head H1 is formed at the lower end of the first stage cooling cylinder C1, and the second stage cold head H2 is formed at the lower end of the second stage cooling cylinder C2. On the upper opening rim of the first stage cooling cylinder C1, the motor drive part M is mounted and at the same time, a flange 41 for mounting to the vacuum container, specifically, for mounting to the vacuum container through the flange 21, is provided. Is installed. The displacer is inserted into the first and second stage cooling cylinders C1 and C2 through the opening of the flange 41.

The sleeve 2 has a first stage sleeve 2a having a first stage cooling flange F1 installed at a lower end thereof, and an upper end thereof connected to the first stage cooling flange F1, and a second stage cooling flange ( F2) is provided with the 2nd stage sleeve 2b. A flange 21 for mounting to the top plate of the vacuum container is provided at the opening edge of the first end sleeve 2a.

Also in this embodiment, the thermal contact interface of the first stage cold head H1 and the first stage cooling flange F1 of the GM refrigerator R, and the second stage cold head H2 and the second stage cooling flange In the thermal contact interface of (F2), indium sheets 3a and 3b each having a thickness of about 0.5 to 1 mm are provided in order to increase thermal contact of these contact surfaces.

Also in this GM refrigerator R, it is possible to make cryogenic temperatures from 70 to 40 K in the first stage cold head H1 and from 20 to 4 K in the second stage cold head H2. The object to be cooled is cooled to a predetermined temperature. That is, as described with reference to FIG. 6, the top plate portion of the heat shield container disposed in the vacuum container is heat-movably mounted to the first stage cooling flange F1, and the superconducting magnet device or the like is mounted on the second stage cooling flange F2. The coolant is brought into heat transferable contact.                     

Also in FIG. 1, the sleeve 2 is shown as a single line ignoring its thickness, and a thermal contact interface is provided between the inner surface of the sleeve 2 and the outer surfaces of the first and second stage cooling cylinders C1 and C2. Except for spaces. The thermal contact interface is a surface perpendicular to the extending direction of the first and second stage cooling cylinders C1 and C2.

The flange 41 provided at the position corresponding to the flange 21 of the sleeve 2, that is, the upper opening rim of the first stage cooling cylinder C1, mounts the motor drive unit M in a state where the displacer is inserted. Plate member 41-1 having an annular shape, and a common portion 41- that is inserted through the upper portion of the sleeve 2 to seal the space in the sleeve 2 together with the plate member 41-1. Has 2). The plate member 41-1 and the normal portion 41-2 are integrated by a bolt (not shown) or the like, and a sealing O-ring 41-3 is provided at these joint portions. In this manner, the first and second stage cooling cylinders C1 and C2 are accommodated in the sleeve 2 in a state in which it is insulated from the vacuum region in the vacuum vessel.

Moreover, between the normal part 41-2 and the inner wall of the sleeve 2 which opposes it, it is made to seal with the O-ring 42 made of rubber | gum. As described later, since the normal portion 41-2 is movable to and from the sleeve 2, there is a slight gap between the inner surface of the sleeve 2 and the outer surface of the ordinary portion 41-2. This is to prevent airtight leakage through this gap.

Between the flange 41 and the flange 21, it is tightened from the lower side of the flange 21 with the some bolt 43 provided with equal angle space | interval. In addition, for the reason mentioned later, the bolt 43 is penetrated by the flange 21 in the state which inserted leisurely. In addition, in the flange 41 and the flange 21, respectively, for regulating the inclination of the first and second stage cooling cylinders C1 and C2 when the ordinary portion 41-2 is inserted into the sleeve 2, respectively. At least one guide pin 44 is provided here, with four equal intervals of 90 degrees. The guide pin 44 is provided perpendicular to the flange 21, and the through hole is provided in the normal part 41-2 and the plate member 41-1 corresponding to it.

Moreover, the spring washer 45 is interposed between the several bolt 43 head part and the flange 21 which this head part opposes among several bolt 43. As shown in FIG. The spring washer 45 generates a bias force that tries to pull the flange 41 downward in the drawing through the bolt 43. That is, the first stage cooling cylinder C1 is cooled when the first cooling start is started, so that the first stage cooling cylinder C1 shrinks. As a result, although the first stage cold head H1 is about to fall from the first stage cooling flange F1, the first stage cold cylinder C1 is pushed down by the spring washer 45, so that the first stage cold head H1 is pushed down. Surface contact between the head H1 and the first stage cooling flange F1 is maintained. 46 is a connector to which pressure reduction means, such as a vacuum pump, for making the space between the sleeve 2 and the 1st stage and 2nd stage cooling cylinders C1 and C2 into a vacuum state is connected.

During maintenance, the GM refrigerator leaves the first and second stage cooling cylinders C1 and C2, and replaces the motor driver M and the displacer with a new motor driver and the displacer.

This replacement operation will be described with reference to Figs.

When the replacement operation is performed, the tightening between the flange 21 and the flange 41 is loosened, and the GM refrigerator R is not completely removed from the sleeve 2 (that is, the inside of the sleeve 2 is kept in the atmosphere. Without exposing), GM refrigerator R is pulled up in the range where sealing by O-ring 42 is possible. This lifting amount is several mm, for example, about 2-3 mm. By this operation, the GM refrigerator R is separated from the sleeve 2, that is, the thermal contact between the sleeve 2 and the first and second stage cold heads H1 and H2 is eliminated, The heat transfer in the case is not performed.

Next, in the cryogenic state, the first stage and second stage cooling cylinders C1 and C2 of the GM refrigerator R are fixed as they are, and the display unit is pulled out together with the motor driving unit M, and a new display unit is mounted together with the motor driving unit. do.

2 shows that the motor driving unit M is pulled out together with the displacers D1 and D2, and the surface contact between the sleeve 2 and the first and second stage cooling cylinders C1 and C2, strictly speaking, The surface contact between the first end sleeve 2a and the first end cold head H1 and the surface contact between the second end sleeve 2b and the second end cold head H2 are released.

In the state of FIG. 2, before mounting the new motor driving unit and the displacer in the first and second stage cooling cylinders C1 and C2, the first stage and the second stage cooling that are exposed to the atmosphere due to the empty frame inside. Since the interior of the cylinders C1 and C2 is low temperature, it is covered with a freezing film and frost. Thus, as shown in FIG. 3, the inside of the first and second stage cooling cylinders C1 and C2 is inserted with a heating device (dryer, etc.) 50 to increase the temperature, and the freezing film or frost is removed and cleaned. do. The temperature increase may be 20 to 40 ° C. In addition to the above, the purpose of the temperature increase includes softening the indium sheets 3a and 3b attached to the lower ends of the first and second stage cold heads H1 and H2.

Either way, there is a vacuum space sealed by the O-ring 42 between the sleeve 2 and the first and second stage cooling cylinders C1 and C2, and the sleeve 2 and the first and second stages. Since the surface contact of the cooling cylinders C1 and C2 is interrupted, the first and second stage cooling cylinders C1 and C2 are not directly cooled by the low temperature on the vacuum container side. On the contrary, thermal intrusion to the vacuum vessel side through the first stage and the second stage cooling cylinders C1 and C2 exposed to the atmosphere can also be prevented, so that the temperature rise on the vacuum vessel side can be minimized.

When the replacement of the motor drive unit and the displacer is completed, in order to return the state in which the first stage and the second stage cooling cylinders C1 and C2 are pulled up by several millimeters, as shown in FIG. The entire GM refrigerator is pushed down by using a force generating device (60). In this case, the inclination of the 1st stage and 2nd stage cooling cylinders C1 and C2 is suppressed by the guide pin 44, and it returns to an almost original position. Moreover, even if there is slight inclination from the softening of the indium sheet, surface contact is possible flexibly.

By the above operation, the heat transfer performance of the first stage and the second stage cold heads H1 and H2 can ensure the same performance as before the exchange.

As mentioned above, although embodiment of this invention was described about GM refrigerator, the refrigerator to which this invention is applied is suitable for being used in combination with the superconducting magnet apparatus provided to a single crystal pulling apparatus, or the superconducting magnet apparatus of other uses. Do.

 According to the present invention, the following effects can be obtained.

1) The deterioration of performance when the refrigerator is replaced during maintenance is very small, and even if the replacement failure is recognized, it can be performed again.

2) Exchange work is very simple and can be done in a short time.

3) Maintenance cost is low.

4) Minimize operational loss of customer equipment caused by maintenance work.

Claims (4)

A refrigerator which is inserted into a vacuum container for storing a to-be-cooled object and performs cooling, comprising: a motor driver, a displacer mounted on the motor driver and driven by the motor driver, and a cylinder for reciprocating the displacer. In the mounting structure for mounting a refrigerator containing the vacuum container, The vacuum vessel is provided with a sleeve having an opening at a position close to the wall of the vacuum vessel as a sleeve for accommodating the cylinder in a state in which it is insulated from the vacuum region in the vacuum vessel. A part of the cylinder is in surface contact with the sleeve, The cylinder is provided with a common portion inserted into the sleeve to seal the space in the sleeve while the motor driving portion is mounted in a state corresponding to the opening of the sleeve. Branches install the first flange, O-ring is sealed between the normal portion and the inner wall of the sleeve opposite thereto, And the motor drive unit and the displacer are removed, leaving the cylinder so as to be replaced with a new displacer. The method of claim 1, The opening of the sleeve is provided with a second flange facing the outer periphery of the first flange, the bolt between the first flange and the second flange to be mounted, and further, the first flange and the second flange And at least one guide pin is provided on the flange to restrict the inclination of the cylinder when the ordinary portion is inserted into the sleeve. The method of claim 2, The bolt penetrates in a state where the second flange is loosely inserted, and a spring washer is interposed between the head of the bolt and the second flange facing the head. Mounting structure of the refrigerator, characterized in that. As a maintenance method of a refrigerator by the mounting structure of the refrigerator of Claim 1, The surface contact of a part of said cylinder and the said sleeve is performed in the surface orthogonal to the extending direction of the said cylinder, The motor drive part is detached from the first flange to be pulled out of the cylinder together with the displacer, and when the extraction is carried out as described above, the first flange and the second flange are loosened and loosened so that the normal part is loosened. The surface contact is released by pulling out a few mm, After inserting a combination of a new motor drive unit and a displacer into the cylinder through the first flange, the normal part is pushed back to its original position, and the part of the cylinder and the sleeve are in surface contact. Maintenance method.

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