DE102011076858A1 - Device for cooling a superconducting machine and method for operating the device - Google Patents

Abstract

The present invention relates to a device (1) for cooling a superconducting machine with at least two cold heads (2a to 2d) and with at least two compressors (3a to 3d). The cold heads (2a to 2d) are each fluidically connected to at least one compressor (3a to 3d) via at least one fluid line (5a to 5d ', 6a to 6d'). According to the invention, the device (1) has at least one fluid collection line (9, 10). The present invention also relates to a method for operating the device described above, in which the compressors (3a to 3d) and the cold heads (2a to 2d) are fluidically connected to one another via the at least one fluid collection line (9, 10).

Description

The present invention relates to an apparatus for cooling a superconducting machine having at least two cold heads and at least two compressors. The cold heads are each fluidly connected via at least one fluid line with at least one compressor. Furthermore, the present invention relates to a method for operating the device described above.

In the cooling of superconducting machines, cold heads, e.g. Gifford-McMahon cold heads used. These provide the necessary refrigeration capacity for the cooling of the parts of the machine, which must be kept at a cryogenic temperature for superconductivity. For liquid nitrogen cooling, e.g. Temperatures below 77K and for liquid helium cooling must be e.g. Temperatures of less than 4K can be achieved with a cooling device.

The cooling device usually comprises a cold head, a compressor unit and associated connecting lines. The connecting lines are often composed of a high and a low pressure line. Via a control line, a cold-head rotary valve, the cooling capacity, which is generated by the compressor unit, control the cold head. Furthermore, taxation is also understood to mean a rule with the aid of a regulation. Thus, e.g. the cold head to the compressor back so that with less need for cooling capacity of the compressor turned off or at least the produced cooling capacity is reduced.

Devices are known from the prior art for cooling, which comprise a plurality of compressor cold head units, each with associated connecting lines. So is for example from the not yet published DE 10 2010 041 194 It is known that in each case a cold head is connected to a compressor via a high-pressure line for supplying the cold head with working fluid. As a rule, the working fluid is a gas such as helium or nitrogen. But it can also be a liquid used as a working fluid. The working fluid is compressed at the compressor, the resulting heat is released to the environment. The compressed working fluid is passed at high pressure through the high pressure line to the cold head. At the cold head, the working fluid is expanded, where it cools and cools the cold head. The expanded, lower pressure working fluid is then returned from the cold head to the compressor via a low pressure line, thereby forming a closed fluid circuit, between a compressor and a coldhead, respectively.

A disadvantage of the devices known from the prior art for cooling superconducting machines is that if they fail, e.g. technical failure of a component of the device, such as a compressor and / or a cold head, the safe cooling of the machine can no longer be guaranteed. Another disadvantage is that with a large change in the desired cooling capacity maintenance times are necessary because to connect another compressor, the device must be completely switched off.

The object of the present invention is therefore to provide a device for cooling a superconducting machine and a method for operating the device, which overcome the problems described above. In particular, it is an object of the device according to the invention to ensure reliable cooling of the machine, even in the event of failure of a component such as e.g. a compressor and / or a cold head. Furthermore, it is an object of the device according to the invention to allow maintenance without having to completely stop the cooling and to take the machine out of service. Another object of the present invention is to provide a method which also solves the problems described above.

The stated object is achieved with respect to the device for cooling a superconducting machine with the features of claim 1 and with respect to the method for operating the device with the features of claim 14.

Advantageous embodiments of the device according to the invention for cooling a superconducting machine and the method for operating the device are apparent from the respectively associated dependent subclaims. In this case, the features of the main claim with features of the subclaims and features of the subclaims can be combined with each other.

The device according to the invention for cooling a superconducting machine comprises at least two cold heads and at least two compressors. The cold heads are each fluidly connected via at least one fluid line with at least one compressor. The device according to the invention comprises at least one fluid collection line.

About the fluid collection line, the compressors and the cold heads are all fluidly connected to each other via a working fluid. If one compressor fails, the remaining compressors can ensure a safe and continuous cooling capacity at the cold heads via the fluid collection line. Also at a maintenance of a Compressor or multiple compressors can be made sure with the help of the remaining compressors a secure supply of all cold heads with working fluid or cooling capacity on the common fluid collection line. As a result, the machine does not have to be taken out of service during compressor maintenance or failure, but cooling of the superconducting components in the machine can be maintained.

The cold heads can each be electrically connected to at least one electrical control line. As a result, a control or regulation of the cold heads depending on the required cooling capacity is possible. The device may have at least one central electrical control, which is electrically connected to the at least one electrical control line, in particular to all electrical control lines. The central electrical control may alternatively or additionally be connected to the at least one compressor. This makes it possible to control the compressors depending on the cooling capacity required at the cooling heads. It may fail in case of failure of a component, e.g. a compressor, via the central electrical control, a control or regulation of the other components such. the other compressors to compensate for the power failure of a failed component.

The at least one fluid conduit may be constructed of at least one high pressure fluid conduit and at least one low pressure fluid conduit. The fluid collection conduit may be constructed of at least one high pressure fluid collection conduit and at least one low pressure fluid collection conduit. Thus, e.g. a working fluid, such as Helium or nitrogen, are compressed by the compressor, i. the pressure of which is increased and transported to the cooling heads via the high pressure fluid line, the high pressure fluid collection line, and further via the high pressure fluid line. The cooling power, which has received the working fluid at the compressor by compression and removal of the resulting amount of heat to the environment, can return the working fluid at the cold head by expansion or pressure reduction again. By lowering the pressure, in particular, an adiabatic expansion takes place with cooling of the working fluid. The cooling capacity releases the working fluid to the cold head while reducing the pressure by heat exchange. The working fluid is then transported to the at least one compressor via the low pressure fluid line, the low pressure fluid collection line and further via the low pressure fluid line, whereby a closed loop can be established. The transport processes of the fluids can be done by pumps, by pressure differences and / or by gravity. In general, the transport is carried out by the pressure differences.

Alternatively, a transport of liquid and / or gaseous working fluid can also take place via separate high-pressure and low-pressure fluid lines via common lines.

The at least two cold heads and the at least two compressors can be fluidly connected to one another via the high-pressure fluid lines, wherein at least two, in particular all, high-pressure fluid lines are fluidically connected to one another via the at least one common high-pressure fluid collection line. The at least two cold heads and the at least two compressors can be fluidly connected to one another via the low-pressure fluid lines, wherein at least two, in particular all, low-pressure fluid lines are fluidically connected to one another via the at least one common low-pressure fluid collection line.

The at least one fluid conduit may comprise at least one valve. This valve may e.g. be an overflow valve or an electrically controllable valve. The at least one fluid conduit constructed of at least one high pressure fluid conduit and at least one low pressure fluid conduit may include at least one valve in each high pressure fluid conduit and / or at least one valve in each low pressure fluid conduit, for avoidance of fluidic backflows and / or for controlling the fluid flows.

The compressors may be or include helium compressors. The fluid collection conduit may be a helium-bus system or part of a helium-bus system. Instead of helium, another working fluid may also be used, e.g. Nitrogen.

The compressors may be or include oily or oil-free compressors, especially linear compressors.

The conduits may include buffer volumes, particularly for damping pressure changes. As a result, a continuous cooling of the machine parts to be cooled is ensured.

The ratio of the number of compressors to the cold heads may not be equal to 1: 1. Since the compressors are fluidically connected to the cold heads via the fluid collection line, there is no need for a 1: 1 assignment of a compressor to a cold head. The cooling capacity can be adjusted by switching compressors on and / or off, and during maintenance, compressors can also be switched off without any intervention Total failure of the machine or the cooling of the machine takes place. This increases the reliability of the device and allows continuous operation without downtime, for example, during maintenance of components.

An inventive method for operating the device described above comprises that the compressors and the cold heads are fluidly connected via at least one common fluid collection line through which in particular a working fluid flows from the compressors to the cold heads and / or vice versa. Through the fluid collection line all compressors are fluidly connected to all cold heads, which has the advantages previously described under the device. In a closed circuit, a continuous and safe cooling and safe operation of the machine or the device to be cooled is made possible.

The number of operating compressors and cold heads can be changed during operation, in particular controlled or regulated by switching on or off the compressors. This can be done in particular via a central electrical control. As a result, it is not necessary to provide a separate control or regulation for each compressor, which saves costs. A common control of the compressors e.g. Depending on the cold heads and / or vice versa or the components of the system dependent on each other, allows a better interaction of the compressors and / or cold heads and better control of the required cold power.

The advantages associated with the method of operating the apparatus for cooling a superconducting machine are analogous to the advantages previously described with respect to the apparatus for cooling a superconducting machine.

Preferred embodiments of the invention with advantageous developments according to the features of the dependent claims are explained in more detail with reference to the figures, but without being limited thereto.

It is shown in the figures:

1 a schematic representation of a device 1 for cooling a superconducting machine with separate compressor 3a to d - cooling head 2a to d - pairs according to the prior art, and

2 a schematic representation of a device according to the invention 1 for cooling a superconducting machine with common fluid collection line 9 . 10 ,

In the 1 is a device 1 for cooling a superconducting machine with separate compressor 3a to d - cooling head 2a to d - pairs shown schematically according to the prior art. In the following, by way of example, with reference to a closed cooling circuit with a compressor 3a to d - cooling head 2a to d - pair described the operation. In 1 are four closed cooling circuits, each with a compressor 3a to d - cooling head 2a to d - pair shown. An apparatus for cooling a superconducting machine may include other numbers of compressor 3a to d - cooling head 2a to d - pairs, eg two, three or more than four.

A compressor 3a to d is in each case via a high-pressure fluid line 5a to d with a cold head 2a connected fluidically to d. That at the compressor 3a to d compressed fluid is at an elevated pressure to the cold head 2a headed to the d. When compressing the compressor 3a to d resulting heat quantities are on the compressor 3a to d, for example, dissipated by a cooling fluid such as water. The transport of the fluid from the compressor 3a to d to the cold head 2a to d is usually due to pressure differences. Alternatively, transportation may also be by gravity or by means of pumps not shown in the figures for the sake of simplicity. The compressor 3a to d can allow the fluid transport but also by the pressure build-up.

At the cold head 2a to d the working fluid gives off cooling capacity, for example by adiabatic expansion associated with a cooling of the fluid. With the cooling capacity of the cold head 2a cooled to d. The working fluid heats up and its pressure is lowered. The expanded working fluid is passed through a low pressure fluid line 6a until d back to the compressor 3a to d, resulting in a closed cooling circuit.

At the compressor 3a to d, the working fluid is again compressed, whereby the previously described process starts from the beginning.

The compressor 3a to d and the cold head 2a to d is in each case via a control line 4a to d electrically connected. The control line 4a to d allows control of the compressor 3a to d provided cooling capacity, eg in the form of compressed working fluid. This may depend on the cold head 2a to d required cooling capacity, which, for example via a temperature sensor on the cold head 2a until d is measured. The control can be a control or regulating device on the cold head 2a to d and / or the compressor 3a to d, which is not shown in the figures for the sake of simplicity.

The cooling of a machine with the device described above 1 is from the prior art, for example, not yet published DE 10 2010 041 194 , known and should therefore not be further discussed below. The cold heads 2a As a rule, the cooling of cooling fluid, which directly or indirectly cools the parts of the machine to be cooled, generally serves to d.

In 2 is a schematic representation of a device according to the invention 1 for cooling a superconducting machine with common fluid collection line 9 . 10 shown. The embodiment in 2 shows four compressors 3a to d and four cold heads 2a to d. Alternatively, other numbers of compressors and cold heads may be used, especially unequal numbers of compressors and cold heads.

The fluid collection line 9 . 10 in the embodiment of 2 is in two-part form, with a high pressure fluid collection line 9 and a low pressure fluid collection line 10 , Alternatively to the version with a separate high pressure fluid collection line 5a to d and a low pressure fluid collection line 6a to d can also only a fluid collection line 9 . 10 be provided, wherein the fluid, for example in liquid form from the compressors 3a to d to the cold heads 2a to d flows and in gaseous form the fluid from the cold heads 2a to d to the compressors 3a until d flows back again.

A compressor 3a to d is in each case via a high-pressure fluid line 5a to d with the high pressure fluid collection line 9 fluidly connected. About the high pressure fluid collection line 9 are thus all compressors 3a to d fluidly connected together. The cold heads 2 to d are each via a high pressure fluid line 5a ' to d 'with the high pressure fluid collection line 9 fluidly connected. About the high pressure fluid collection line 9 are therefore all cold heads 2a to d fluidly connected together.

That at the compressors 3a to d each compressed fluid becomes an elevated pressure to the cold heads 2a headed to the d. This can be done by gravity, by means of pumps not shown in the figures for the sake of simplicity or by pressure difference. The most technically simple way is through the compressor 3a to d produced pressure differences. To a return flow of cooling fluid from the high pressure fluid collection line 9 to the compressors 3a To prevent d, a valve can 7a to 7d , For example, an overcurrent or backflow valve or an electrically controllable valve, respectively in the high-pressure fluid lines 5a to d to the compressors 3a be provided to d.

At the cold heads 2a to d respectively, the working fluid gives off cooling capacity, for example by adiabatic expansion associated with a cooling of the fluid. With the cooling capacity of the respective cold head 2a cooled to d. The working fluid heats up and its pressure is reduced. The expanded working fluid is passed through a low pressure fluid line 6a until d 'again to the compressor 3a headed to the d. This is done via a common low pressure fluid collection line 10 , The cold heads 2a to d are each fluidly via a low pressure fluid line 6a ' to d 'with the low pressure fluid collection line 10 connected. The compressors 3a to d are also each fluidly via a low pressure fluid line 6a to d with the low pressure fluid collection line 10 connected. Through the common low pressure fluid collection line 10 are thus all compressors 3a to d with each other and with all cold heads 2a to fluidly connected to d, which are thereby also fluidly connected to each other.

To return flows from the compressors 3a to d to the low pressure fluid collection line 10 can prevent in any low-pressure fluid line 6a ' to d 'from the cooling heads 2a to d to the low pressure fluid collection line 10 down and / or in any low pressure fluid line 6a to d from the low pressure fluid collection line 10 to the compressors 3a to d valves 7e be provided to h, for example, overflow valves or return valves or controllable valves.

It's starting from the compressors 3a to d via the high pressure fluid lines 4a to d, the high pressure fluid collection pipe 9 , the high-pressure fluid lines 4a ' to d 'to the cold heads 2a to d back and forth from the cold heads 2a to d, via the low pressure fluid lines 5a ' to d 'and via the low pressure fluid collection line 10 and the low pressure fluid lines 5a to d to the compressors 3a created a closed cooling circuit to d.

At the compressors 3a to d, the working fluid is compressed, allowing it to heat up and release the heat to cooling water or other form to the environment.

The compressors 3a to d and the cold heads 2a to d can each have a control line 4a to d with own control, as in 1 shown to be electrically connected to each other or via a common electrical control 8th , as in 2 shown. The control 8th can be electric only with the cold heads 2a to be connected to d and these taxes, as in 2 shown. Alternatively, not shown in the figures, the controller 8th via control lines with the compressors 3a to d and the cold heads 2a be connected to d. This allows control of the compressor 3a to d each provided cooling capacity, for example in the form of compressed working fluid, and at the same time the cold heads 2a to d, respectively, according to the cooling capacity required at the cold heads. This can eg on the cold heads 2a to d each be provided a temperature sensor, which at the cold head 2a until d measures the temperature. The control can be a control or regulating device on the cold head 2a to d and / or the compressor 3a to d, which is not shown in the figures for the sake of simplicity. Alternatively, it is a central controller 8th provided as they are in 2 is shown.

In the pipes 5a to d ', 6a to d ', 9 and 10 Buffer volumes may be provided which are not shown in the figures for the sake of simplicity. The buffer volumes can buffers or reduce this pressure fluctuations, which leads to an improved, ie more continuous cooling. The collecting lines 9 and or 10 can also be designed as buffer volumes or unfold their effect.

By using a common circuit between all compressors 3a to d and all cold heads 2a to d via the common collection lines 9 and 10 as it is in 2 is shown in the invention, in contrast to the prior art, see 1 each with separate circuits, each having a compressor 3a to d and a cold head 2a to fluid connect d, achieved a higher reliability of the apparatus for cooling a superconducting machine. The compressors 3a to d of the device according to the invention can also be easily maintained because when switching off or failure of a compressor 3a to d an increase in the power of the other compressors 3a to d the power of a compressor 3a to replace d. The system also becomes more flexible by allowing compressors to be switched on or off as cooling performance requirements change without taking the device out of service and shutting down the machine.

The inventive embodiments and variants described above can be used individually and in combination. They may also be used in combination with what has been described as well as well known prior art embodiments. Thus, e.g. different arrangements of the controller and the components to be controlled possible. Coolants such as helium or nitrogen may be used singly or in combination. Also, an arrangement of additional valves, such as e.g. Return valves or electrically controlled or controlled valves in the collection line and / or the lines to the cold heads and / or the compressors out possible.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010041194 [0004, 0032]

Claims (15)

Contraption ( 1 ) for cooling a superconducting machine having at least two cold heads ( 2a to 2d ) and with at least two compressors ( 3a to 3d ), whereby the cold heads ( 2a to 2d ) in each case via at least one fluid line ( 5a to 5d ' . 6a to 6d ' ) fluidly with at least one compressor ( 3a to 3d ), characterized in that the device ( 1 ) at least one fluid collection line ( 9 . 10 ) having. Contraption ( 1 ) according to claim 1, characterized in that the cold heads ( 2a . 2 B . 2c . 2d ) each with at least one electrical control line ( 4a to 4d ) are electrically connected. Device according to claim 2, characterized in that the device ( 1 ) at least one central electrical control ( 8th ), which with the at least one electrical control line ( 4a to 4d ), in particular with all electrical control lines ( 4a to 4d ) is electrically connected and / or with at least one compressor ( 3a to 3d ) is electrically connected. Device according to one of the preceding claims, characterized in that the at least one fluid conduit ( 5a to 5d ' . 6a to 6d ' ) each of at least one high-pressure fluid line ( 5a to 5d ' ) and at least one low-pressure fluid line ( 6a to 6d ' ) is constructed. Device according to one of the preceding claims, characterized in that the fluid collection line ( 9 . 10 ) from at least one high-pressure fluid collection line ( 9 ) and from at least one low-pressure fluid collection line ( 10 ) is constructed. Apparatus according to claim 5, characterized in that the at least two cold heads ( 2a to 2d ) and the at least two compressors ( 3a to 3d ) via the high pressure fluid lines ( 5a to 5d ' ) are fluidly connected to each other, wherein at least two, in particular all high-pressure fluid lines ( 5a to 5d ' ) via the at least one common high-pressure fluid collection line ( 9 ) are fluidly connected to each other. Device according to one of claims 5 or 6, characterized in that the at least two cold heads ( 2a to 2d ) and the at least two compressors ( 3a to 3d ) via the low pressure fluid lines ( 6a to 6d ' ) are fluidly connected to each other, wherein at least two, in particular all low-pressure fluid lines ( 6a to 6d ' ) via the at least one common low-pressure fluid collection line ( 10 ) are fluidly connected to each other. Device according to one of the preceding claims, characterized in that the at least one fluid conduit ( 5a to 5d ' . 6a to 6d ' ) at least one valve ( 7a to 7h ). Device according to one of claims 4 to 8, characterized in that the at least one fluid conduit ( 5a to 5d ' . 6a to 6d ' ), which consists of at least one high-pressure fluid line ( 5a to 5d ' ) and at least one low-pressure fluid line ( 6a to 6d ' ), at least one valve ( 7a to 7d ) in each high-pressure fluid line ( 5a to 5d ' ) and / or at least one valve ( 7e to 7h ) in each low-pressure fluid line ( 6a to 6d ' ), to avoid fluidic backflow. Device according to one of the preceding claims, characterized in that the compressors ( 3a . 3b . 3c . 3d ) Helium compressors are or comprise and / or that the fluid collection line ( 9 . 10 ) is a helium bus system or is part of a helium bus system. Device according to one of the preceding claims, characterized in that the compressors ( 3a . 3b . 3c . 3d ) Oil-containing or oil-free compressors are or include, in particular linear compressors. Device according to one of the preceding claims, characterized in that the lines ( 5a to 5d ' . 6a to 6d ' . 9 . 10 ) Comprise buffer volumes, in particular for damping pressure changes. Device according to one of the preceding claims, characterized in that the ratio of the number of compressors ( 3a to 3d ) to the cold heads ( 2a to 2d ) is not equal to 1: 1. Method for operating a device according to one of the preceding claims, characterized in that the compressors ( 3a to 3d ) and the cold heads ( 2a to 2d ) via at least one common fluid collection line ( 9 . 10 ) are fluidically connected, by which in particular a working fluid from the compressors ( 3a to 3d ) to the cold heads ( 2a to 2d ) and / or vice versa. Method according to claim 14, characterized in that the number of compressors in operation ( 3a to 3d ) and / or cold heads ( 2a to 2d ) is changed during operation, in particular by switching on or off controlled or regulated in particular a central electrical control ( 8th ).

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