KR102038415B1 - Method for controlling cryogenic water pump - Google Patents

Abstract

The present invention relates to a method for controlling a cryogenic water pump which is used to create a high-vacuum environment in various industrial fields including a semiconductor fabrication field. The cryogenic water pump comprises: a plurality of extremely low temperature refrigerators provided to expand a refrigerant gas to create an extremely low temperature; one compressor individually connected to the plurality of extremely low temperature refrigerators to supply the refrigerant gas of a high pressure to the extremely low temperature refrigerators; and a control unit controlling the extremely low temperature refrigerators and the compressor. Furthermore, the control method comprises: a step that the extremely low temperature refrigerators have a ticket to receive the refrigerant gas from the compressor; a step that the control unit allows only the extremely low temperature refrigerators having the ticket to receive the refrigerant gas from the compressor; a step that the extremely low temperature refrigerators return the ticket to the control unit after reaching a first temperature; a step that the extremely low temperature refrigerators request the ticket to the control unit after reaching a second temperature that is higher than the first temperature; and a step that the control unit imparts the ticket to the extremely low temperature refrigerators that issued a request such that the extremely low temperature refrigerators may receive the refrigerant gas. Therefore, in the water pump, the single compressor can effectively control a plurality of extremely low temperature refrigerators, while maintaining the desired moisture collecting performance.

Description

Control method for cryogenic water pump {Method for controlling cryogenic water pump}

The present invention relates to a method for controlling a cryogenic water pump used to create a high vacuum environment in various industries, including semiconductor production.

Cryopumps are vacuum pumps used to create a high to ultra high vacuum environment in many industries, including semiconductor production. Cryogenic water pump (hereinafter referred to as Cryogenic waterpump) is a kind of cryopump that is specially manufactured to mainly remove moisture in the vacuum area. Water pumps can be broadly divided into 1) direct type, 2) in-line type, and 3) exposed type (nude type), depending on the type installed in the vacuum chamber.

The operation principle of the water pump uses a cycle similar to that of a normal refrigeration cycle, and helium (He) is used as a refrigerant. The water pump is basically composed of a pump body unit serving as an indoor unit and a compressor unit serving as an outdoor unit, like a refrigeration system of a general air conditioner. The two units are connected by a flexible helium hose and an additional monitor is available to check the temperature.

1 is a view showing the configuration of a conventional water pump of the exposure type.

The water pump includes a cryogenic freezer 10, and the cryogenic freezer 10 is connected to the compressor 40 through a hose 30.

In general, when the cryogenic freezer 10 is operated to be in a steady state, the first stage adapter 11, which is the head portion of the freezer, is maintained at about 30 to 40K at no load. The one-stage adapter 11 is provided with a cooling metal plate 20 for collecting moisture.

After the refrigerant gas (for example, helium) compressed by the compressor 40 is moved to the cryogenic freezer 10 through the hose 30, the temperature decreases while being expanded in the cryogenic freezer 10. In the cryogenic freezer, there is a reciprocating device in which a screen network is stacked, and the reciprocating device reciprocates vertically and induces cold storage and gas flow through heat exchange with the cooled refrigerant gas.

Through this, the temperature of the first stage adapter 11 of the refrigerator gradually falls to cryogenic temperature, and the opposite motor side always maintains the room temperature. The refrigerant dropped to the low pressure is recovered back to the compressor via a motor and a hose (30) mounted in the freezer. This cooling principle is called G-M refrigeration cycle.

However, when the water pump is connected to the actual process chamber and under a load condition, the temperature of the first stage adapter 11 should be maintained at approximately 100 to 110K. This is because the purpose of the water pump is not to collect process gases such as nitrogen, argon or oxygen, but to collect only moisture, which generally occupies most of the vacuum region.

Several water pumps may be used in the process chamber depending on the collection capacity of water, and one water pump is used for one compressor 40. In recent years, however, several water pumps (cryogenic refrigerators 10) may be connected to reduce costs. At this time, the cryogenic freezer 10 by the control unit repeats the operation and stop according to the temperature of the metal cooling plate 20 mounted on the first stage side adapter (11).

That is, since the cryogenic freezer 10 of the water pump is not continuously operated, but is repeatedly operated and stopped according to the temperature of the metal cold plate 20, three or more cryogenic freezers 10 are controlled by one compressor 40. While properly controlling the operation and stop of each cryogenic freezer (10), it will be possible to operate a system that can maintain the water collection capacity of one compressor unit without degrading the performance of each cryogenic freezer (10). This can reduce the cost of the compressor 10 in the total system using a plurality of cryogenic freezer (10).

Republic of Korea Patent Application No. 10-2012-0110362

Accordingly, the present invention has been invented in view of the above circumstances, and a method for controlling a cryogenic water pump capable of maintaining a desired water collection capability while efficiently controlling three or more cryogenic refrigerators with one compressor in a cryogenic water pump. The purpose is to provide.

In the control method of a water pump for supplying a high-pressure refrigerant gas to three or more cryogenic freezers with one compressor according to the present invention for realizing the above object, the water pump expands the refrigerant gas to form a cryogenic temperature And a plurality of cryogenic freezers, one compressor connected to each of the plurality of cryogenic freezers, for supplying a high-pressure refrigerant gas to the cryogenic freezer, and a control unit for controlling the cryogenic freezer and the compressor. Holding a ticket for receiving refrigerant gas from the compressor; Allowing the control unit to receive the refrigerant gas from the compressor only the cryogenic refrigerator having the ticket; Returning the reserved ticket to the controller when the cryogenic freezer reaches the first temperature; Requesting a ticket from the controller when the cryogenic freezer reaches a second temperature higher than the first temperature; The control unit granting a ticket to the cryogenic freezer having a request to allow the cryogenic freezer to receive refrigerant gas; It includes.

Further, when a ticket request is received from any one of the cryogenic freezers, if the ticket returned to the controller is less than or equal to a predetermined number, not granting a ticket to the cryogenic freezer containing the request; When the cryogenic freezer reaches the first temperature and returns the ticket to the controller, when the ticket held by the controller exceeds the predetermined number, the controller grants a ticket to the cryogenic freezer in which the request is received. Allowing the cryogenic freezer to receive a refrigerant gas; It includes.

In addition, when a ticket request is received from any one of the cryogenic freezer, if the ticket held by the controller is less than a predetermined number, not granting a ticket to the corresponding cryogenic freezer; Controlling the controller to increase the motor speed of the other cryogenic refrigerator to a first RPM; When the other cryogenic freezer reaches the first temperature and returns a ticket to the controller, when the ticket held by the controller exceeds the predetermined number, the controller grants a ticket to the cryogenic freezer in which the request is received. To allow the cryogenic freezer to receive the refrigerant gas; It includes.

In addition, when a ticket request is received from any one of the cryogenic freezer, if the ticket held by the controller is less than a predetermined number, not granting a ticket to the corresponding cryogenic freezer; Controlling the controller to increase the motor speed of the other cryogenic refrigerator to a first RPM; If the temperature of the cryogenic freezer having the request reaches a third temperature higher than the second temperature, controlling to increase the motor speed of the other cryogenic freezer to a second RPM greater than the first RPM; When the other cryogenic freezer reaches the first temperature and returns a ticket to the controller, when the ticket held by the controller exceeds the predetermined number, the controller grants a ticket to the cryogenic freezer in which the request is received. To allow the cryogenic freezer to receive the refrigerant gas; It includes.

According to the present invention, it is possible to provide a control method of a cryogenic water pump capable of maintaining a desired water collecting ability while efficiently controlling three or more cryogenic refrigerators with one compressor in a water pump.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the conventional cryogenic water pump.
Fig. 2 is a diagram showing the configuration of the cryogenic water pump of the present invention.
3 is a view showing the configuration of the cryogenic freezer of FIG.
4A-4L illustrate a control method for operating several refrigerators with one compressor in the cryogenic water pump of the present invention.
5A-5E illustrate a method of controlling the motor speed of each refrigerator to operate several refrigerators with one compressor in the cryogenic water pump of the present invention.

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, in adding reference numerals to the elements of each drawing, it should be noted that the same elements are denoted by the same reference numerals as much as possible even if they are shown in different drawings.

Fig. 2 is a diagram showing the configuration of the cryogenic water pump of the present invention. 3 is a view showing the configuration of the cryogenic freezer of FIG. 4A-4L illustrate a control method for operating several refrigerators with one compressor in the cryogenic water pump of the present invention. 5A-5E illustrate a method of controlling the motor speed of each refrigerator to operate several refrigerators with one compressor in the cryogenic water pump of the present invention.

The present invention provides a control method for maintaining a desired water collection capacity while efficiently controlling three or more cryogenic refrigerators with one compressor in a cryogenic water pump (hereinafter, referred to as a water pump). Water pumps can be broadly divided into 1) direct type, 2) in-line type, and 3) exposed type (nude type), depending on the type installed in the vacuum chamber. The present invention can be applied regardless of the type of water pump, and will be described below with reference to the exposure type.

2, the water pump of the present invention includes a plurality of cryogenic refrigerators 110, a compressor 140, and a controller 150.

The cryogenic refrigerator 110 expands the high-pressure refrigerant gas supplied from the compressor 140 to form cryogenic temperatures. When the cryogenic refrigerator 110 is operated to be in a steady state, the first stage adapter 111, which is the end of the cryogenic refrigerator 110, is maintained at about 30 to 40K at no load. The first stage adapter 111 is connected to a metal cooling plate 120 for collecting moisture.

The refrigerant gas (for example, helium) compressed by the compressor 140 is moved to the cryogenic freezer 110 through the hose 130, and is then expanded in the cryogenic freezer 110, thereby lowering the temperature. The cryogenic refrigerator 110 has a reciprocating device in which a screen network is stacked, and the reciprocating device causes up-and-down reciprocating motion to cause cold storage and gas flow through heat exchange with the cooled refrigerant gas. Through this, the temperature of the first stage adapter 111 of the cryogenic freezer 110 gradually falls to the cryogenic temperature, and the opposite motor side always maintains the room temperature. The refrigerant dropped to the low pressure is recovered to the compressor 140 through the motor and the hose 130 mounted on the cryogenic refrigerator 110. This cooling principle is called the G-M refrigeration cycle.

The controller 150 controls the cryogenic freezer 110 and the compressor 140.

2 and 3, the cryogenic freezer 110 includes a freezer body 112, a motor 113, a reciprocator 115, an inlet valve 116, and an outlet valve 117.

The refrigerator body 112 has an accommodation space in which various components can be accommodated. The refrigerator 113 includes a motor 113, an inlet valve 116, an outlet valve 117, and the like.

The motor 113 is accommodated in the freezer body 112 to transmit power so that the reciprocator 115 can perform a linear motion.

The reciprocator 115 is connected to the motor 113 is a linear movement by the rotational movement of the motor 113. A hollow space is formed in the reciprocator 115, and the coolant may be accommodated in the hollow space. The rotational motion of the motor 113 may be converted into linear motion by a power transmission mechanism such as the yoke arm 114 and transmitted to the reciprocator 115. While the reciprocator 115 performs a linear motion, the temperature of the metal cooling plate 120 is lowered to 100 K or less through heat exchange with the refrigerant gas.

The compressor 140 compresses the refrigerant gas to generate a high pressure refrigerant gas. The generated high pressure refrigerant gas is supplied into the freezer body 112 through the inlet valve 116. In addition, the low-pressure refrigerant gas from the freezer body 112 is discharged through the outlet valve 117 and recovered to the compressor 140.

Inlet valve 116 is accommodated in the freezer body 112 is connected to the compressor 140, and may be opened and closed in conjunction with the rotation of the motor 113. The inlet valve 116 may be controlled to open and close the high pressure refrigerant gas supplied from the compressor 140 into the freezer body 112. The high pressure refrigerant gas supplied from the compressor 140 is supplied into the freezer body 112 through a flow path formed in the freezer body 112, and an inlet valve 116 is installed in the middle of the flow path.

The outlet valve 117 is accommodated in the freezer body 112 and connected to the compressor 140 may be opened and closed to discharge the low-pressure refrigerant gas expanded in the freezer body 112. The outlet valve 117 may also be opened and closed in conjunction with the rotation of the motor 113. The refrigerant gas discharged through the outlet valve 117 is recovered to the compressor 140. The refrigerant gas discharged from the freezer body 112 is recovered to the compressor 140 through a flow path formed in the freezer body 112, and an outlet valve 117 is installed in the middle of the flow path.

Hereinafter, a method of controlling a water pump for operating three or more cryogenic refrigerators 110 with one compressor 140 will be described with reference to FIGS. 2, 3, and 4A to 4L.

Referring to FIG. 4A, the cryogenic refrigerator 110 has a ticket T for receiving a high-pressure refrigerant gas from the compressor 140. Here, the ticket (T) means the authority to receive a high-pressure refrigerant gas from the compressor 140, and without the ticket (T), the cryogenic refrigerator 110 cannot receive the refrigerant gas from the compressor 140. .

The controller 150 may supply the refrigerant gas from the compressor 140 by controlling the motor 113 of the cryogenic refrigerator 110 to supply the refrigerant gas only to the cryogenic refrigerator 110 having the ticket T. To be. When the motor 113 rotates, the reciprocator 115 linearly moves, and refrigerant gas may be supplied from the compressor 140 into the cryogenic freezer 110 through the inlet valve 116 interlocked with the rotation of the motor 113. have. The method of supplying the refrigerant gas to the cryogenic refrigerator 110 may be other methods known in the art in addition to the control of the motor 113.

In FIG. 4A, before the load connection, the three cryogenic refrigerators 110 have all the tickets T and are supplied with the refrigerant gas from the compressor 140. At this time, the temperature of the cryogenic refrigerator 110 is 293K, and the rotation speed of the motor is operated at 90 RPM, which is the maximum operation limit. Before the load connection, it is possible to supply the refrigerant gas to three cryogenic refrigerators 110 with one compressor 140.

Referring to FIG. 4B, a ticket held when the cryogenic freezer 110 (or the metal cold plate 120) reaches a first temperature, for example, 100K, by heat transfer by reciprocation of the reciprocator in the cryogenic freezer 110 on the left side. (T) is returned to the controller 150.

When the cryogenic freezer 110 returns the ticket T, the controller 150 does not supply the refrigerant gas to the cryogenic freezer 110 that returned the ticket T. At this time, the control unit 150 has one usable ticket and one holding ticket. Here, the usable ticket actually refers to the ticket that can supply the refrigerant T to the cryogenic freezer 110 to supply the refrigerant gas, and the reserved ticket refers to the total number of tickets T held by the controller 150. .

Referring to FIG. 4C, the cryogenic refrigerator 110 at the center reaches the first temperature and returns the ticket T held to the first temperature to the controller 150, and the cryogenic refrigerator 110 returning the ticket T returns the refrigerant gas. Not supplied At this time, the control unit 150 has two usable tickets and two holding tickets.

Referring to FIG. 4D, the cryogenic refrigerator 110 of the right side reaches the first temperature and returns the ticket T held to the first temperature to the controller 150, and the cryogenic refrigerator 110 returning the ticket T returns the refrigerant gas. Not supplied At this time, the control unit 150 has two usable tickets and three holding tickets. Here, the reason why there are fewer usable tickets than the reserved ticket is that when all the reserved tickets are used, it is difficult to efficiently control three cryogenic refrigerators 110 with one compressor 140 under load.

Referring to FIG. 4E, since the cryogenic freezer 110 on the left side returning the ticket T does not receive the refrigerant gas, the temperature rises over time. The cryogenic refrigerator 110 requests the ticket T to the controller 150 while reaching the second temperature higher than the first temperature, for example, 110K. 4E illustrates a state in which a water pump is connected to a load.

Referring to FIG. 4F, the controller 150 grants the ticket T to the cryogenic freezer 110 on the left requesting the ticket T so that the cryogenic freezer 110 receives the refrigerant gas from the compressor 140. . Accordingly, the controller 150 grants one piece from the usable ticket T to have one usable ticket and two reserved tickets.

Referring to FIG. 4G, since the cryogenic freezer 110 in the middle of returning the ticket T does not receive the refrigerant gas, it requests the ticket T to the controller 150 while reaching 110K as time passes.

Referring to FIG. 4H, the controller 150 grants the ticket T to the cryogenic freezer 110 in the middle of requesting the ticket T, such that the cryogenic freezer 110 receives the refrigerant gas from the compressor 140. . Accordingly, the controller 150 has no usable ticket and has one reserved ticket. The reason why there is one reserved ticket but no usable ticket is that when the refrigerant gas is supplied to all three cryogenic freezers 110 using one remaining reserved ticket, the temperature of the three cryogenic freezers 110 is efficiently controlled. As it is hard to do, we hold without using one piece for spare.

Referring to FIG. 4I, since the cryogenic freezer 110 on the right side that returns the ticket T does not receive the refrigerant gas, the ticket T reaches the control unit 150 while reaching the second temperature 110K as time passes. Ask.

Referring to FIG. 4J, if the holding ticket (or the ticket returned to the controller 150) is a predetermined number, for example, 1 or less, the controller 150 does not grant the ticket to the cryogenic freezer 110 in which the request is received. Wait for it.

At this time, the control unit 150 may rotate the rotational speed of the motor of the other cryogenic freezer 110 having the ticket T, that is, the cryogenic freezer 110 on the left and the center, from the original RPM to the first RPM, for example, 72. To increase to 76. By increasing the rotation speed of the motor of the other cryogenic refrigerator 110, the other cryogenic refrigerator 110 may return the ticket T by quickly reaching the first temperature 100K while receiving more refrigerant gas.

Referring to FIG. 4K, the cryogenic freezer 110 on the left side that reaches 100K first returns the ticket T to the controller 150, so that the controller 150 can use one ticket and two holding tickets. The number of tickets T held is more than one, which is a predetermined number.

Referring to FIG. 4L, the controller 150 grants the ticket T to the cryogenic freezer 110 on the right side in which the request is received so that the cryogenic freezer 110 receives the refrigerant gas. At this time, the controller 150 controls the RPM of the motor of the cryogenic freezer 110 on the right to the maximum limit of 90 so that the elevated temperature can be quickly lowered.

According to the control method of the water pump of the present embodiment, by supplying the refrigerant T by supplying the ticket T to the cryogenic refrigerator 110 only when the ticket T held by the controller 150 exceeds a predetermined number, One compressor can efficiently control the temperature of three or more cryogenic freezers.

Hereinafter, a method of controlling the rotation speed of the motor of the cryogenic refrigerator 110 when there is no usable ticket T will be described with reference to FIGS. 5A to 5E.

Referring to FIG. 5A, the control unit 150 has one usable ticket and two holding tickets, and controls the motor of the cryogenic freezer 110 on the left side at 72 RPM.

Referring to FIG. 5B, the controller 150 assigns one usable ticket to the cryogenic freezer 110 in the middle, and has 0 usable tickets and 1 reserved ticket. At this time, the ticket (T) request is received from the cryogenic freezer 110 on the right, but the control unit 150 does not have a ticket available, the cryogenic freezer 110 on the right will wait.

In this case, the controller 150 sets the motor rotational speed of the other cryogenic refrigerator 110 at a first RPM, for example, in order to quickly give the ticket T to the cryogenic refrigerator 110 on the right side. For example, it controls to increase from 72 to 76.

Referring to FIG. 5C, when the temperature of the cryogenic freezer 110 on the right side at which the ticket T request is reached reaches a third temperature, for example, 115K, the motor speed of the other cryogenic freezer 110 is greater than the first RPM. Control to increase to a second RPM, for example 90. Accordingly, the temperature of the other cryogenic freezer 110 is lowered faster to return the ticket T, thereby allowing the ticket T to be given to the cryogenic freezer 110 on the right side.

Referring to FIG. 5D, when the cryogenic freezer 110 on the left reaches the first temperature 100K and returns the ticket T to the controller 150, the controller 150 may use one ticket and a holding ticket 2. You have a chapter.

Referring to FIG. 5E, when the number of tickets T held by the controller 150 exceeds a predetermined number, 1, the controller 150 grants the ticket T to the cryogenic freezer 110 on the right side in which the request is received. The compressor 140 may supply the refrigerant gas. At this time, the controller 150 controls the rotation speed of the motor of the cryogenic freezer 110 on the right side to 90 RPM, which is the maximum limit, so that the temperature can be lowered quickly.

According to the control method of the water pump of the present embodiment, when there is a ticket T request from any one cryogenic freezer 110 when the number of tickets T held by the controller 150 is less than or equal to a predetermined number, the other cryogenic freezer Control to increase the rotational speed of the motor (110). Accordingly, by quickly lowering the temperature of the other cryogenic freezer 110, it is possible to quickly give the ticket T to the cryogenic freezer 110 that the request came in.

By such a control method, the temperature of three or more cryogenic refrigerators can be efficiently controlled by one compressor.

It will be apparent to those skilled in the art that the present invention is not limited to the above embodiments and can be practiced in various ways without departing from the technical spirit of the present invention. will be.

110: cryogenic freezer
111: 1-stage adapter
112: freezer body
113: motor
115: shuttle
116: inlet valve
117: outlet valve
120: metal cold plate
130: hose
140: compressor
150: control unit
T: Ticket

Claims (4)

In a control method of a cryogenic water pump for supplying a high-pressure refrigerant gas to three or more cryogenic freezers with one compressor,
The water pump includes a plurality of cryogenic freezers for expanding the refrigerant gas to form cryogenic temperature, one compressor connected to each of the plurality of cryogenic freezers and supplying a high-pressure refrigerant gas to the cryogenic freezer, the cryogenic freezer and the A control unit for controlling the compressor,
Allowing the cryogenic freezer to hold a ticket for receiving refrigerant gas from the compressor;
Allowing the control unit to receive the refrigerant gas from the compressor only the cryogenic refrigerator having the ticket;
Returning the reserved ticket to the controller when the cryogenic freezer reaches the first temperature;
Requesting a ticket from the controller when the cryogenic freezer reaches a second temperature higher than the first temperature;
The control unit granting a ticket to the cryogenic freezer having a request to allow the cryogenic freezer to receive refrigerant gas;
Control method of the cryogenic water pump comprising a. The method of claim 1,
When a ticket request is received from any one of the cryogenic freezers, if a ticket returned to the controller is less than or equal to a predetermined number, not granting a ticket to the cryogenic freezer having the request;
When the cryogenic freezer reaches the first temperature and returns the ticket to the controller, when the ticket held by the controller exceeds the predetermined number, the controller grants a ticket to the cryogenic freezer in which the request is received. Allowing the cryogenic freezer to receive a refrigerant gas;
Control method of the cryogenic water pump comprising a. The method of claim 1,
When a ticket request is received from any one of the cryogenic freezers, if a ticket held by the controller is less than or equal to a predetermined number, not granting a ticket to the corresponding cryogenic freezer;
Controlling the controller to increase the motor speed of the other cryogenic refrigerator to a first RPM;
When the other cryogenic freezer reaches the first temperature and returns a ticket to the controller, when the ticket held by the controller exceeds the predetermined number, the controller grants a ticket to the cryogenic freezer in which the request is received. To allow the cryogenic freezer to receive the refrigerant gas;
Control method of the cryogenic water pump comprising a. The method of claim 1,
When a ticket request is received from any one of the cryogenic freezers, if a ticket held by the controller is less than or equal to a predetermined number, not granting a ticket to the corresponding cryogenic freezer;
Controlling the controller to increase the motor speed of the other cryogenic refrigerator to a first RPM;
If the temperature of the cryogenic freezer having the request reaches a third temperature higher than the second temperature, controlling to increase the motor speed of the other cryogenic freezer to a second RPM greater than the first RPM;
When the other cryogenic freezer reaches the first temperature and returns a ticket to the controller, when the ticket held by the controller exceeds the predetermined number, the controller grants a ticket to the cryogenic freezer in which the request is received. To allow the cryogenic freezer to receive the refrigerant gas;
Control method of the cryogenic water pump comprising a.

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