CN211953339U

CN211953339U - Refrigerant circulation system and air conditioner with same

Info

Publication number: CN211953339U
Application number: CN201922338164.6U
Authority: CN
Inventors: 魏会军; 李海港; 单彩侠; 刘双来; 董航江; 赵玉晨; 马鹏
Original assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai
Current assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai; Zhuhai Gree Energy Saving Environmental Protection Refrigeration Technology Research Center Co Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2020-11-17
Anticipated expiration: 2029-12-23

Abstract

The application provides a refrigerant circulation system, includes: the system comprises a compressor, an enhanced vapor injection system and a liquid spraying system; the enhanced vapor injection system is used for guiding a gaseous enhanced vapor refrigerant to enter the compression cavity through the gas supplementing port; the liquid spraying system is used for guiding the liquid cooling refrigerant to enter the compression cavity through the liquid spraying port; the gas pressure in the compression chamber at the location of the make-up port is P1; the gas pressure in the compression cavity at the position of the liquid spraying port is P2; where P1 ≠ P2. According to the refrigerant circulation system and the air conditioner with the same, the pressure at the positions of the air supplementing port and the liquid supplementing port of the compressor is different, and the air supplementing or liquid spraying effect of the scroll compressor can be effectively improved.

Description

Refrigerant circulation system and air conditioner with same

Technical Field

The application belongs to the technical field of air conditioners, and particularly relates to a refrigerant circulating system and an air conditioner with the same.

Background

At present, the scroll compressor has the characteristics of simple structure, small volume, light weight, low noise, high mechanical efficiency, stable operation and the like. When the ambient temperature is relatively low, the suction specific volume of the refrigerant is increased, the mass flow of the refrigerant is reduced, the heating capacity is correspondingly reduced, and the working efficiency of the scroll compressor is reduced accordingly. When the ambient temperature drops to below zero degree centigrade, evaporating temperature crosses lowly, ordinary refrigeration air conditioning system is used for heating and can lead to scroll compressor to compress and compress the increase, has repeated compression to make scroll compressor exhaust temperature sharply rise, exceed the working range that scroll compressor allows, cause scroll compressor frequent start-stop, the unable normal work of system can lead to scroll compressor to burn out when serious. In order to solve the problems of low working efficiency and rapid rise of exhaust temperature of the scroll compressor, the solution method in the prior art is to introduce low-temperature steam from a flash evaporator or an economizer or throttle a part of high-temperature and high-pressure refrigerant liquid at the outlet of a condenser into a lower-temperature gas-liquid two-phase valve rod to be directly sprayed into a compression cavity of the scroll compressor, so as to achieve the purposes of improving the working efficiency of the scroll compressor and reducing the exhaust temperature.

However, when the ambient temperature is lower, i.e. the evaporation temperature is ultra-low, the conventional enthalpy-increasing scroll compressor cannot effectively reduce the discharge temperature of the scroll compressor, and the reliability of the scroll compressor is reduced.

Therefore, how to provide a scroll compressor capable of improving the gas supply or liquid spraying effect of the scroll compressor becomes a problem to be solved by those skilled in the art.

SUMMERY OF THE UTILITY MODEL

Therefore, an object of the present invention is to provide a refrigerant circulation system and an air conditioner having the same, which can improve the air supply or liquid spraying effect of a scroll compressor.

In order to solve the above problem, the present application provides a refrigerant circulation system, including:

a compressor including a compression chamber;

the enhanced vapor injection system is used for guiding a gaseous enhanced vapor refrigerant to enter the compression cavity through the gas supplementing port;

the liquid spraying system is used for guiding the liquid cooling refrigerant to enter the compression cavity through the liquid spraying port; the gas pressure in the compression chamber at the location of the make-up port is P1; the gas pressure in the compression cavity at the position of the liquid spraying port is P2; where P1 ≠ P2.

Preferably, the compressor is a scroll compressor, the scroll compressor comprises a fixed scroll and an orbiting scroll, and the orbiting scroll is engaged with the fixed scroll to form a compression chamber; the distance between the air supplementing port and the central axis of the fixed scroll is d 1; the distance between the liquid spraying port and the central axis of the fixed scroll disk is d 2; wherein d1> d 2;

and/or, P2> P1;

and/or, the refrigerant circulating system also comprises a temperature detection device; the temperature detection device is used for detecting the exhaust temperature of the scroll compressor.

Preferably, the suction port pressure of the scroll compressor is P; p1 is 1.01-1.43P; and/or P2 is 1.31-2.21P.

Preferably, the refrigerant circulating system further comprises a first controller, and the first controller is connected with the temperature detection device; the first controller is used for controlling the opening and closing of the enhanced vapor injection system and the liquid spraying system.

Preferably, the refrigerant circulation system further comprises a switching device; the first controller is connected with the switching device; the switching device is used for switching the enhanced vapor injection system and the liquid spraying system.

Preferably, the switching means comprises a three-way valve; the first controller is connected with the three-way valve; the first valve port of the three-way valve is used for guiding liquid cooling refrigerant or gaseous enthalpy-increasing refrigerant to enter; the second valve port is communicated with the enhanced vapor injection system, and the third valve port is communicated with the liquid spraying system.

Preferably, the three-way valve comprises a shell and a core body, and a control cavity is arranged in the shell; the first valve port, the second valve port and the third valve port are all arranged on the shell and communicated with the control cavity; the first controller is connected with the core body; the core body is used for plugging the second valve port, and the third valve port is opened to be at a first position; the core body is used for plugging the third valve port, and the second valve port is opened to be at a second position; the first controller controls the core to be movable between a first position and a second position.

Preferably, the enhanced vapor injection system comprises an injection chamber, and the injection chamber is communicated with the second valve port and the air supplementing port; and/or the liquid spraying system further comprises a liquid spraying chamber, and the liquid spraying chamber is communicated with the third valve port and the liquid spraying port.

Preferably, the enhanced vapor injection system comprises a vapor injection channel; the air injection channel is communicated with the air injection chamber and the air supplement port;

and/or, the liquid spray system comprises a liquid spray channel; the liquid spraying channel is communicated with the liquid spraying chamber and the liquid spraying port;

and/or, the scroll compressor further comprises a splitter shell and a divider; the partition portion partitions the interior of the flow dividing casing to form a spray chamber and a gas ejection chamber.

Preferably, the core body comprises a valve rod, a first valve core and a second valve core are arranged on the valve rod, and the shape and the size of the first valve core correspond to those of the second valve port; the shape and the size of the second valve core correspond to those of the third valve port; the first valve core is used for sealing the second valve port, and the second valve core opens the third valve port to be a first position; the second valve core is used for sealing the third valve port, and the first valve core opens the second valve port to be at a second position; the first controller controls the core to be movable between a first position and a second position.

Preferably, the compressor comprises a compressor shell, and the fixed scroll and the movable scroll and the temperature detection device are arranged in the compressor shell;

and/or the refrigerant circulating system also comprises a first heat exchanger, a flash evaporator, a throttling element, a second heat exchanger and a second controller; the first valve port is communicated with a steam outlet of the flash evaporator through a first pipeline; the first valve port is communicated with the outlet end of the throttling element through a second pipeline; the second controller is used for controlling the opening and closing of the first pipeline and the second pipeline.

Preferably, the liquid spraying channel is arranged inside the compressor shell or outside the compressor shell;

and/or the gas injection passage is arranged inside the scroll compressor shell or outside the scroll compressor shell.

According to another aspect of the present application, an air conditioner is provided, which includes a refrigerant circulation system as described above.

The application provides a refrigerant circulation system and have its air conditioner, the pressure of compressor tonifying qi mouth and compressor hydrojet mouth position department is different, can effectually improve scroll compressor and carry out tonifying qi or hydrojet effect.

Drawings

FIG. 1 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 2 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 3 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 4 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 5 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 6 is a schematic view of an installation configuration of a scroll compressor according to an embodiment of the present application;

FIG. 7 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 8 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 9 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 10 is a schematic structural view of a scroll compressor in accordance with an embodiment of the present application;

FIG. 11 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

FIG. 12 is a schematic view of the mounting structure of the scroll compressor according to the embodiment of the present application

FIG. 13 is a schematic structural view of a movable scroll according to an embodiment of the present application;

FIG. 14 is a schematic view of the structure of a fixed scroll according to an embodiment of the present application;

FIG. 15 is a schematic structural view of a scroll compressor according to an embodiment of the present application;

fig. 16 is a schematic structural view of a compression chamber according to an embodiment of the present application.

The reference numerals are represented as:

1. an enhanced vapor injection system; 11. an air injection passage; 111. a first ejection head; 112. a third seal ring; 12. an air ejection chamber; 2. a liquid spraying system; 21. a liquid ejection channel; 211. a second ejection head; 212. a fourth seal ring; 22. a spray chamber; 3. a temperature detection device; 4. a housing; 41. a control chamber; 42. a core body; 421. a first valve spool; 422. a second valve core; 43. a first valve port; 44. a second valve port; 45. a third valve port; 5. feeding a pipe; 6. a first gasket; 7. a second seal ring; 8. a fixed scroll; 81. an air injection communicating passage; 82. a spray liquid communication channel; 9. a movable scroll; 91. an air supplement port; 92. and a liquid spraying port.

Detailed Description

Referring to fig. 1-3 in combination, according to an embodiment of the present application, a refrigerant circulation system includes: the system comprises a compressor, an enhanced vapor injection system 1 and a liquid spraying system 2, wherein the compressor comprises a compression cavity; the enhanced vapor injection system 1 is used for guiding a gaseous enhanced vapor refrigerant to enter a compression cavity through the gas supplementing port 91; the liquid spraying system 2 is used for guiding liquid cooling refrigerants to enter the compression cavity through the liquid spraying port 92; the gas pressure in the compression chamber at the location of the make-up port 91 is P1; the gas pressure in the compression chamber at the position of the liquid jet 92 is P2; wherein P1 ≠ P2, and the pressure of compressor tonifying qi mouth and compressor hydrojet mouth position department is different, can effectual improvement scroll compressor carry out tonifying qi or hydrojet effect.

Further, the compressor is a scroll compressor, the scroll compressor comprises a fixed scroll and a movable scroll, and the movable scroll is engaged with the fixed scroll to form a compression cavity; the distance between the air supplementing port 91 and the central axis of the fixed scroll is d 1; the distance between the liquid spraying port 92 and the central axis of the fixed scroll is d 2; wherein d1> d 2;

and/or, P2> P1;

and/or, the coolant circulating system also includes the temperature detection device 3; the temperature detection device 3 detects the discharge temperature of the scroll compressor.

Further, the pressure of the air suction port of the scroll compressor is P; p1 is 1.01-1.43P; and/or P2 is 1.31-2.21P.

Fig. 16 is a schematic diagram of the meshing of the molded lines of the dynamic and static scrolls, wherein a compression cavity sealed by the molded line on the outer side of the dynamic scroll and the molded line on the inner side of the static scroll is an outer cavity, and a compression cavity sealed by the molded line on the inner side of the dynamic scroll and the molded line on the outer side of the static scroll is an inner cavity. When enthalpy is increased, the outer cavity is opened at 5-180 degrees, the theoretical pressure ratio of the compression cavity is 1.01-1.31, the pressure of the compression cavity is the pressure of the suction pressure; the inner cavity is opened at 185-360 degrees, and the theoretical pressure ratio of the compression cavity is 1.01-1.43. When liquid is sprayed, the inner cavity is opened at 20-160 ℃, and the theoretical pressure ratio of the compression cavity is 1.49-2.21; the outer cavity is opened at 180-360 degrees, and the theoretical pressure ratio of the compression cavity is 1.31-1.87. It can be found that the compression pressure ratio of the inner cavity and the outer cavity is larger than that of the compression cavity when enthalpy is increased during liquid spraying, so that air supply or liquid spraying can be effectively carried out.

Referring to fig. 4-6 in combination, the present application further discloses some embodiments, the refrigerant circulation system further includes a first controller, and the first controller is connected to the temperature detection device 3; the first controller is used for controlling the opening and closing of the enhanced vapor injection system 1 and the liquid spraying system 2.

Furthermore, the refrigerant circulating system also comprises a switching device; the first controller is connected with the switching device; the switching device is used for switching the enhanced vapor injection system 1 and the liquid spraying system 2, has dual functions of enhanced vapor injection and liquid spraying, and can switch the enhanced vapor injection and the liquid spraying according to the exhaust temperature value, for example, the vapor injection system is opened in fig. 1, the liquid spraying system 2 is closed, the vapor injection system is closed in fig. 2, and the liquid spraying system 2 is opened. The reliability of the scroll compressor is effectively improved, the operation range of the scroll compressor is widened, and the reliability of the scroll compressor in the environment with wider evaporation temperature is improved.

Further, the switching device includes a three-way valve; the first controller is connected with the three-way valve; the first valve port 43 of the three-way valve is used for guiding liquid cooling refrigerant or gaseous enthalpy-increasing refrigerant to enter; the second port 44 is in communication with the enhanced vapor injection system 1, and the third port 45 is in communication with the hydrojet system 2.

Further, the three-way valve comprises a shell 4 and a core 42, wherein a control cavity 41 is arranged in the shell 4; the first valve port 43, the second valve port 44 and the third valve port 45 are all arranged on the shell 4 and communicated with the control cavity 41; the first controller is connected to the core 42; the core body 42 is used for blocking the second valve port 44 and opening the third valve port 45 to be at a first position; the core body 42 is used for sealing the third valve port 45 and opening the second valve port 44 to be at a second position; the first control controls the core 42 to be movable between a first position and a second position.

Further, the enhanced vapor injection system 1 comprises an air injection chamber 12, wherein the air injection chamber 12 is communicated with the second valve port 44 and the air supplement port 91; and/or, liquid spraying system 2 further comprises liquid spraying chamber 22, and liquid spraying chamber 22 is communicated with third valve opening 45 and liquid spraying opening 92.

Referring collectively to fig. 11-14, the enhanced vapor injection system 1 includes a gas injection passage 11; the air injection channel 11 is communicated with the air injection chamber 12 and the air supplement port 91;

and/or, aqueous jet system 2 includes an aqueous jet channel 21; the liquid ejection passage 21 communicates the liquid ejection chamber 22 with the liquid ejection port 92;

and/or, the scroll compressor further comprises a splitter shell and a divider; the partition part partitions the interior of the flow dividing shell into a spraying chamber 22 and a spraying chamber 12, and the scroll compressor comprises a fixed scroll 8 and a movable scroll; the movable scroll is movably arranged in the fixed scroll 8, and a compression cavity is formed between the side wall of the fixed scroll 8 and the side wall of the movable scroll; when the enhanced vapor injection system 1 comprises the liquid spraying channel 21, the liquid spraying system 2 comprises the gas spraying channel 11; when the liquid spraying channel 21 and the air spraying channel 11 are both arranged inside the shell of the scroll compressor; the fixed scroll 8 is provided with a liquid spraying port 92 and an enthalpy increasing port, and the liquid spraying channel 21 is communicated to the compression cavity through the liquid spraying port 92; the air injection channel 11 is communicated to the compression cavity through an enthalpy increasing port; the first injection head 111 and the second injection head 211 are provided with second sealing rings 7 for being hermetically connected with the fixed scroll 8 to prevent leakage of a gas enthalpy-increasing refrigerant and leakage of a liquid cooling refrigerant, or when the enhanced vapor injection system 1 comprises a liquid injection channel 21, the liquid injection system 2 comprises an air injection channel 11; when the liquid spraying channel 21 and the air spraying channel 11 are both arranged outside the shell of the scroll compressor; the fixed scroll 8 is provided with a liquid spraying communication channel 82 and an enthalpy increasing communication channel; the liquid spraying communication channel 82 and the enthalpy increasing communication channel extend from the outer periphery side of the fixed scroll 8 to the position of a compression cavity, and the liquid spraying channel 21 is communicated to the compression cavity through the liquid spraying communication channel 82; the air injection channel 11 is communicated to the compression cavity through an enthalpy-increasing communication channel, and a third sealing ring 112 is arranged on the first injection head 111 and is used for being in sealing connection with the fixed scroll 8 to prevent the leakage of a gaseous enthalpy-increasing refrigerant; the second discharge head 211 is provided with a fourth seal 212 for sealing connection with the fixed scroll 8 and preventing leakage of the liquid cooling refrigerant.

Further, the core body 42 includes a valve stem, a first valve core 421 and a second valve core 422 are disposed on the valve stem, and the shape and size of the first valve core 421 correspond to those of the second valve port 44; the shape and the size of the second valve core 422 correspond to those of the third valve opening 45; the first valve core 421 is used for blocking the second valve port 44, and the second valve core 422 is used for opening the third valve port 45 to be at the first position; the second valve core 422 is used for sealing the third valve port 45, and the first valve core 421 opens the second valve port 44 to be at the second position; the first control controls the core 42 to be movable between a first position and a second position.

Further, the compressor comprises a compressor shell, wherein the fixed scroll and the movable scroll and the temperature detection device 3 are arranged in the compressor shell;

and/or the refrigerant circulating system also comprises a first heat exchanger, a flash evaporator, a throttling element, a second heat exchanger and a second controller; the first valve port 43 is communicated with a steam outlet of the flash evaporator through a first pipeline; the first valve port 43 is communicated with the outlet end of the throttling element through a second pipeline; the second controller is used for controlling the opening and closing of the first pipeline and the second pipeline.

Further, a first sealing gasket 6 is arranged between the flow dividing shell and the shell 4, so that leakage of liquid cooling refrigerants or gaseous enthalpy-increasing refrigerants is prevented.

Further, the first head 111 is provided on the end of the gas ejection passage 11 communicating with the compression chamber, and the second head 211 is provided on the end of the liquid ejection passage 21 communicating with the compression chamber.

Furthermore, the shunt shell is connected with the shell 4, and the shunt shell is provided with an air injection shunt hole and a liquid injection shunt hole; the position of the jet flow dividing hole corresponds to that of the second valve port 44; the spray distribution holes correspond to the third valve opening 45.

Referring to fig. 1-10 in combination, the present application also discloses embodiments in which the liquid spray passage 21 is disposed inside or outside the compressor housing;

and/or, the gas injection channel 11 is arranged inside the scroll compressor shell or outside the scroll compressor shell, as shown in fig. 8, the gas injection system is opened, and the liquid injection system 2 is closed, and as shown in fig. 7, the gas injection system is closed, and the liquid injection system 2 is opened.

According to an embodiment of the present application, an air conditioner includes a refrigerant circulation system, and the refrigerant circulation system is the above-mentioned refrigerant circulation system.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed. The foregoing is only a preferred embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present application, and these modifications and variations should also be considered as the protection scope of the present application.

Claims

1. A refrigerant circulation system, comprising:

a compressor including a compression chamber;

the enhanced vapor injection system (1), the enhanced vapor injection system (1) is used for guiding the gaseous enhanced vapor refrigerant to enter the compression cavity through the air supplementing port (91);

the liquid spraying system (2) is used for guiding a liquid cooling refrigerant to enter the compression cavity through a liquid spraying port (92); the pressure of the gas in the compression cavity at the position of the air supplementing port (91) is P1; the gas pressure in the compression cavity at the position of the liquid spraying port (92) is P2; where P1 ≠ P2.

2. The refrigerant circulation system as claimed in claim 1, wherein the compressor is a scroll compressor, the scroll compressor includes a fixed scroll and an orbiting scroll, the orbiting scroll is engaged with the fixed scroll to form the compression chamber; the distance between the air supplementing opening (91) and the central axis of the fixed scroll is d 1; the distance between the liquid spraying opening (92) and the central axis of the fixed scroll is d 2; wherein d1> d 2;

and/or, P2> P1;

and/or, the refrigerant circulating system also comprises a temperature detection device (3); the temperature detection device (3) is used for detecting the exhaust temperature of the scroll compressor.

3. The refrigerant circulation system as claimed in claim 2, wherein a suction port pressure of the scroll compressor is P; p1 is 1.01-1.43P; and/or P2 is 1.31-2.21P.

4. The coolant circulation system according to claim 2, further comprising a first controller connected to the temperature detecting device (3); the first controller is used for controlling the opening and closing of the enhanced vapor injection system (1) and the liquid spraying system (2).

5. The coolant circulation system of claim 4, further comprising a switching device; the first controller is connected with the switching device; the switching device is used for switching the enhanced vapor injection system (1) and the liquid spraying system (2).

6. The coolant circulation system according to claim 5, wherein the switching means includes a three-way valve; the first controller is connected with the three-way valve; a first valve port (43) of the three-way valve is used for guiding the liquid cooling refrigerant or the gaseous enthalpy-increasing refrigerant to enter; the second valve port (44) is communicated with the enhanced vapor injection system (1), and the third valve port (45) is communicated with the liquid spraying system (2).

7. The refrigerant circulation system according to claim 6, wherein the three-way valve comprises a housing (4) and a core (42), and a control chamber (41) is provided in the housing (4); the first valve port (43), the second valve port (44) and the third valve port (45) are all arranged on the shell (4) and communicated with the control cavity (41); the first controller is connected with the core body (42); the core body (42) is used for blocking the second valve port (44), and the third valve port (45) is opened to be at a first position; the core body (42) is used for blocking the third valve port (45) and opening the second valve port (44) to be at a second position; the first controller controls the core (42) to be movable between a first position and a second position.

8. The refrigerant cycle system as claimed in claim 7, wherein the enhanced vapor injection system (1) comprises an injection chamber (12), the injection chamber (12) communicating the second valve port (44) with the gas supplementing port (91); and/or, the liquid spraying system (2) further comprises a liquid spraying chamber (22), and the liquid spraying chamber (22) is communicated with the third valve opening (45) and the liquid spraying opening (92).

9. Refrigerant cycle system according to claim 8, wherein the enhanced vapor injection system (1) comprises an injection channel (11); the air injection channel (11) is communicated with the air injection chamber (12) and the air supplement port (91);

and/or, the liquid spraying system (2) comprises a liquid spraying channel (21); the liquid spraying channel (21) is communicated with the liquid spraying chamber (22) and the liquid spraying opening (92);

and/or, the scroll compressor further comprises a splitter shell and a divider; the partition portion partitions the interior of the flow dividing casing to form the spray chamber (22) and the air ejection chamber (12).

10. The refrigerant cycle system as claimed in claim 7, wherein the core body (42) comprises a valve stem, a first valve core (421) and a second valve core (422) are disposed on the valve stem, and the shape and size of the first valve core (421) and the second valve port (44) correspond to each other; the shape and the size of the second valve core (422) correspond to those of the third valve port (45); the first valve core (421) is used for blocking the second valve port (44), and the second valve core (422) is used for opening the third valve port (45) to be at a first position; the third valve port (45) is blocked by the second valve core (422), and the second valve port (44) is opened by the first valve core (421) to be at a second position.

11. The refrigerant circulation system according to claim 9, wherein the compressor includes a compressor housing, the fixed scroll and the orbiting scroll and the temperature detecting device (3) are disposed in the compressor housing;

and/or the refrigerant circulating system also comprises a first heat exchanger, a flash evaporator, a throttling element, a second heat exchanger and a second controller; the first valve port (43) is communicated with a steam outlet of the flash evaporator through a first pipeline; the first valve port (43) is communicated with the outlet end of the throttling element through a second pipeline; the second controller is used for controlling the opening and closing of the first pipeline and the second pipeline.

12. The refrigerant circulation system as claimed in claim 11, wherein the liquid spraying passage (21) is disposed inside the compressor housing or outside the compressor housing;

and/or the gas injection passage (11) is arranged inside the scroll compressor shell or outside the scroll compressor shell.

13. An air conditioner comprising a refrigerant circulation system, wherein the refrigerant circulation system is the refrigerant circulation system as claimed in any one of claims 1 to 12.