阅读说明：本技术 一种高压气瓶密封结构 (High-pressure gas cylinder sealing structure ) 是由 郝加封 高沛 朱旺 陈珺珺 刘丙胜 李山峰 刘韬 陈汝蒋 吴健聪 于 2021-07-21 设计创作，主要内容包括：本发明提供一种高压气瓶密封结构,包括盖帽、上压盖、密封楔、大密封环、小密封环、下密封座、瓶口塞、密封圈和穿线管；所述瓶口塞包括从上到下固定连接的瓶口塞第一组件、瓶口塞第二组件和瓶口塞第三组件,瓶口塞第一组件和瓶口塞第三组件外侧壁设有外螺纹；所述瓶口塞第一组件和瓶口塞第二组件中开设有瓶口塞管孔,瓶口塞第三组件底部正中心开设置有瓶口塞固定孔,瓶口塞固定孔内壁设置有内螺纹,瓶口塞管孔延伸到瓶口塞第三组件中与瓶口塞固定孔连通；瓶口塞管孔和瓶口塞固定孔共同贯穿瓶口塞的顶部和底部；本发明能在气瓶充气过程,保证分布在气瓶内的温度传感器的数据传输线在瓶口处密封良好。(The invention provides a high-pressure gas cylinder sealing structure which comprises a cover cap, an upper gland, a sealing wedge, a large sealing ring, a small sealing ring, a lower sealing seat, a bottle mouth plug, a sealing ring and a threading pipe, wherein the upper gland is arranged on the cover cap; the bottle opening plug comprises a bottle opening plug first component, a bottle opening plug second component and a bottle opening plug third component which are fixedly connected from top to bottom, and external threads are arranged on the outer side walls of the bottle opening plug first component and the bottle opening plug third component; the first bottle opening plug component and the second bottle opening plug component are provided with bottle opening plug pipe holes, the center of the bottom of the third bottle opening plug component is provided with a bottle opening plug fixing hole, the inner wall of the bottle opening plug fixing hole is provided with internal threads, and the bottle opening plug pipe holes extend into the third bottle opening plug component and are communicated with the bottle opening plug fixing hole; the hole of the bottle opening plug and the fixing hole of the bottle opening plug jointly penetrate through the top and the bottom of the bottle opening plug; the invention can ensure that the data transmission lines of the temperature sensors distributed in the gas cylinder are well sealed at the cylinder opening in the gas charging process of the gas cylinder.)

1. A high-pressure gas cylinder sealing structure is characterized in that: comprises a cap (1), an upper gland (2), a sealing wedge (3), a large sealing ring (4), a small sealing ring (5), a lower sealing seat (6), a bottleneck plug (7), a sealing ring (8) and a threading pipe (9);

the bottle opening plug (7) comprises a first bottle opening plug component (71), a second bottle opening plug component (72) and a third bottle opening plug component (73) which are fixedly connected from top to bottom, and external threads are arranged on the outer side walls of the first bottle opening plug component (71) and the third bottle opening plug component (73);

a bottle opening plug pipe hole (721) is formed in the bottle opening plug first component (71) and the bottle opening plug second component (72), a bottle opening plug fixing hole (731) is formed in the center of the bottom of the bottle opening plug third component (73), internal threads are formed in the inner wall of the bottle opening plug fixing hole (731), and the bottle opening plug pipe hole (721) extends into the bottle opening plug third component (73) to be communicated with the bottle opening plug fixing hole (731); the bottle neck plug pipe hole (721) and the bottle neck plug fixing hole (731) jointly penetrate through the top and the bottom of the bottle neck plug (7);

the side wall of the bottle opening plug second component (72) is provided with an inflation inlet (722) communicated with the bottle opening plug pipe hole (721);

the inner side of the opening of the gas cylinder (16) is provided with internal threads, the third component (73) of the opening plug is in threaded connection with the gas cylinder (16),

a cap fixing cavity (1001) is formed in the bottom of the cap (1), steps (1002) are arranged on the periphery of the top of the cap fixing cavity (1001), and internal threads are formed in the bottom of the inner side wall of the cap fixing cavity (1001); the top of the cap (1) is provided with an outlet (1004) communicated with the cap fixing cavity (1001);

the first bottle neck plug component (71) is in threaded connection with a cap fixing cavity (1001) of the cap (1), and an upper gland (2), a sealing wedge (3) and a lower sealing seat (6) are sequentially and tightly pressed between the bottom of the step (1002) and the top of the first bottle neck plug component (71) from top to bottom;

the upper gland (2) and the lower sealing seat (6) are provided with an upper gland wire outlet hole (21) and a lower sealing seat wire outlet hole (61) which correspond to each other, the periphery of the bottom of the upper gland wire outlet hole (21) of the upper gland (2) is provided with a conical surface (211), and the periphery of the top of the lower sealing seat wire outlet hole (61) of the lower sealing seat (6) is provided with a lower sealing seat fixing groove (611);

the sealing wedge (3) is frustum-shaped, the bottom of the sealing wedge (3) is embedded into the lower sealing seat fixing groove (611), and the side wall of the sealing wedge (3) is abutted to the conical surface (211);

the top of the outer side wall of the threading pipe (9) is provided with external threads, the top of the threading pipe (9) is in threaded connection with the bottleneck plug fixing hole (731), and when the threading pipe is used, the top of the threading pipe (9) is screwed into the bottleneck plug fixing hole (731) until the threading pipe reaches the top of the bottleneck plug fixing hole (731);

the threading tube (9) is hollow and tubular, the inner cavity of the threading tube (9) is communicated with the bottleneck plug tube hole (721), and a plurality of threading tube air inlets (191) are arranged on the side wall of the threading tube (9) at equal intervals from top to bottom;

the threading pipe (9) is also provided with a plurality of temperature sensors, the temperature sensors are transmitted through leads, and the leads penetrate through the wire pipe air inlet hole (191), the inner cavity of the threading pipe (9) and the bottle neck plug pipe hole (721), then penetrate out of the upper gland wire outlet hole (21), the sealing wedge (3) and the lower sealing seat wire outlet hole (61), and are led out of the wire outlet (1004).

2. An apparatus for measuring the internal temperature of a high pressure gas cylinder according to claim 1, characterized in that:

the bottle opening plug second assembly (72) is in the shape of a hexagon bolt, and the diameter of the bottle opening plug second assembly (72) is larger than the diameters of the bottle opening plug first assembly (71) and the bottle opening plug third assembly (73).

3. An apparatus for measuring the internal temperature of a high pressure gas cylinder according to claim 2, characterized in that:

the bottle opening plug pipe hole (721) and the bottle opening plug fixing hole (731) are both positioned on the central axis of the bottle opening plug (7), and the diameter of the bottle opening plug fixing hole (731) is larger than that of the bottle opening plug pipe hole (721).

4. A device for measuring the internal temperature of a high-pressure gas cylinder according to claim 3, characterized in that:

the outer side wall of the third component (73) of the bottle opening plug is provided with a sealing ring (8), and the sealing ring (8) is located below the external thread of the outer side wall of the third component (73) of the bottle opening plug.

5. An apparatus for measuring the internal temperature of a high pressure gas cylinder according to claim 4, characterized in that:

a clamping table (1003) is arranged on the step (1002), and the upper gland (2) is embedded into the clamping table (1003) to be fixed.

6. An apparatus for measuring the internal temperature of a high pressure gas cylinder according to claim 5, characterized in that:

set up big sealing ring (4) between last gland (2) and lower seal receptacle (6), set up corresponding last gland recess (22) and lower seal receptacle first recess (62) on last gland (2) bottom and lower seal receptacle (6) top, during gland recess (22) and lower seal receptacle first recess (62) were gone into respectively to big sealing ring (4) both ends, sealing wedge (3) were located big sealing ring (4) inboardly.

7. An apparatus for measuring the internal temperature of a high pressure gas cylinder according to claim 6, characterized in that:

set up little sealing ring (5) down between seal receptacle (6) and bottleneck stopper first subassembly (71), set up corresponding lower seal receptacle second recess (63) and bottleneck stopper first subassembly recess (711) on seal receptacle (6) bottom and bottleneck stopper first subassembly (71) top down, during seal receptacle second recess (63) and bottleneck stopper first subassembly recess (711) were embedded respectively in little sealing ring (5) both ends, sealing wedge (3) and bottleneck stopper tube hole (721) all were located little sealing ring (5), little sealing ring (5) play sealed effect.

8. An apparatus for measuring the internal temperature of a high pressure gas cylinder according to claim 7, characterized in that:

the sealing tank (8) is made of nitrile rubber, and the sealing wedge (3), the large sealing ring (4) and the small sealing ring (5) are made of polytetrafluoroethylene.

9. An apparatus for measuring the internal temperature of a high pressure gas cylinder according to claim 8, characterized in that:

the bottom of the lower sealing seat (6) is provided with annular lower sealing seat bulges (64) on the periphery, and the top of the first component (71) of the bottleneck plug is embedded into the lower sealing seat bulges (64) to be fixed.

Technical Field

The invention relates to the technical field of hydrogen energy, in particular to a high-pressure gas cylinder sealing structure.

Background

The hydrogen energy has the advantages of wide source, high energy efficiency, renewability, zero pollution of combustion products and the like, and is the focus of energy innovation and re-industrialization of main developed economy and countries in the world. In recent years, strategies for hydrogen energy development have been developed in the united states, japan, china, korea, european union, and the like, so that hydrogen energy automobiles have been vigorously developed, and the construction of hydrogen energy infrastructures such as hydrogen stations has been actively promoted.

In the development process of the hydrogen energy industry chain, a hydrogen refueling station is one of hydrogen supply basic settings, and has received attention of researchers all over the world. According to different hydrogen storage modes, the hydrogen station can be divided into a gas hydrogen station and a liquid hydrogen station. As the gas hydrogen hydrogenation station has the advantages of low energy consumption, high hydrogenation speed, high reliability and the like, the existing hydrogen station in China is mostly adopted. In order to improve the market competitiveness of hydrogen energy in the energy and traffic industries, the hydrogenation is required to be ensured to be convenient, safe, efficient and economic like refueling. Therefore, the temperature rise in the vehicle-mounted hydrogen storage container in the hydrogenation process is strictly controlled by using technical means on the premise of ensuring the hydrogen filling rate and pressure, so that the potential safety hazard caused by the temperature rise is eliminated, and therefore, the temperature of different parts in the gas cylinder in the inflation process needs to be measured and researched.

The existing temperature measuring device has the following defects:

the problem of sealing the data transmission line of the temperature sensor at the bottle mouth cannot be solved.

Accordingly, there is a need for improvements in the art.

Disclosure of Invention

The invention aims to provide an efficient high-pressure gas cylinder sealing structure.

In order to solve the technical problem, the invention provides a high-pressure gas cylinder sealing structure which comprises a cover cap, an upper gland, a sealing wedge, a large sealing ring, a small sealing ring, a lower sealing seat, a bottle mouth plug, a sealing ring and a threading pipe, wherein the upper gland is arranged on the cover cap;

the bottle opening plug comprises a bottle opening plug first component, a bottle opening plug second component and a bottle opening plug third component which are fixedly connected from top to bottom, and external threads are arranged on the outer side walls of the bottle opening plug first component and the bottle opening plug third component;

the first bottle opening plug component and the second bottle opening plug component are provided with bottle opening plug pipe holes, the center of the bottom of the third bottle opening plug component is provided with a bottle opening plug fixing hole, the inner wall of the bottle opening plug fixing hole is provided with internal threads, and the bottle opening plug pipe holes extend into the third bottle opening plug component and are communicated with the bottle opening plug fixing hole; the hole of the bottle opening plug and the fixing hole of the bottle opening plug jointly penetrate through the top and the bottom of the bottle opening plug;

an inflation inlet communicated with the tube hole of the bottle opening plug is formed in the side wall of the second assembly of the bottle opening plug;

the inner side of the bottle opening of the gas bottle is provided with internal threads, the third component of the bottle opening plug is in threaded connection with the gas bottle,

the bottom of the cap is provided with a cap fixing cavity, steps are arranged around the top of the cap fixing cavity, and the bottom of the side wall in the cap fixing cavity is provided with internal threads; the top of the cap is provided with a wire outlet communicated with the cap fixing cavity;

the first component of the bottleneck plug is in threaded connection with a cap fixing cavity of a cap, and an upper gland, a sealing wedge and a lower sealing seat are sequentially and tightly pressed between the bottom of the step and the top of the first component of the bottleneck plug from top to bottom;

the upper gland and the lower sealing seat are provided with corresponding upper gland wire outlet holes and lower sealing seat wire outlet holes, the upper gland is provided with conical surfaces around the bottom of the upper gland wire outlet hole, and the lower sealing seat is provided with lower sealing seat fixing grooves around the top of the lower sealing seat wire outlet hole;

the sealing wedge is frustum-shaped, the bottom of the sealing wedge is embedded into the lower sealing seat fixing groove, and the side wall of the sealing wedge is abutted to the conical surface;

the top of the threading pipe is screwed into the bottle opening plug fixing hole until reaching the top of the bottle opening plug fixing hole;

the threading pipe is hollow and tubular, the inner cavity of the threading pipe is communicated with the hole of the bottle opening plug, and a plurality of threading pipe air inlets are arranged on the side wall of the threading pipe at equal intervals from top to bottom;

the threading pipe is also provided with a plurality of temperature sensors, the temperature sensors transmit through leads, and the leads penetrate through the wire pipe air inlet hole, the threading pipe inner cavity and the bottleneck plug pipe hole, then penetrate out of the upper gland wire outlet hole, the sealing wedge and the lower sealing seat wire outlet hole, and are led out from the wire outlet.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

the bottle opening plug second component is in the shape of a hexagon bolt, and the diameter of the bottle opening plug second component is larger than the diameters of the bottle opening plug first component and the bottle opening plug third component.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

the bottle opening plug pipe hole and the bottle opening plug fixing hole are both located on the central axis of the bottle opening plug, and the diameter of the bottle opening plug fixing hole is larger than that of the bottle opening plug pipe hole.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

the outer side wall of the third component of the bottle opening plug is provided with a sealing ring, and the sealing ring is positioned below the external thread of the outer side wall of the third component of the bottle opening plug.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

a clamping table is arranged on the step, and the upper gland is embedded into the clamping table to be fixed.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

the large sealing ring is arranged between the upper gland and the lower sealing seat, the bottom of the upper gland and the top of the lower sealing seat are provided with a corresponding upper gland groove and a corresponding first lower sealing seat groove, two ends of the large sealing ring are respectively embedded into the upper gland groove and the first lower sealing seat groove, and the sealing wedge is positioned on the inner side of the large sealing ring.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

set up little sealing ring under between seal receptacle and bottleneck stopper first subassembly, set up corresponding lower seal receptacle second recess and bottleneck stopper first subassembly recess on seal receptacle bottom and the bottleneck stopper first subassembly top down, during seal receptacle second recess and bottleneck stopper first subassembly recess are filled in respectively to little sealing ring both ends embedding, sealed wedge and bottleneck stopper tube hole all are located little sealing ring, little sealing ring plays sealed effect.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

the sealing tank is made of nitrile rubber, and the sealing wedge, the large sealing ring and the small sealing ring are made of polytetrafluoroethylene.

As an improvement of an apparatus for measuring the internal temperature of a high-pressure gas cylinder of the present invention:

the bottom of the lower sealing seat is provided with annular lower sealing seat bulges around, and the top of the first component of the bottleneck plug is embedded into the lower sealing seat bulges to be fixed.

The sealing structure of the high-pressure gas cylinder has the technical advantages that:

after the cap and the bottleneck plug are screwed up through threads, the upper gland is pressed downwards, and the sealing wedge penetrated with the lead is extruded and sealed by the conical surface on the upper gland, so that the good sealing around the lead is ensured. Meanwhile, the large sealing ring between the upper gland and the lower sealing seat and the small sealing ring between the lower sealing seat and the bottle mouth plug are also extruded and sealed, so that the high-pressure gas in the bottle is prevented from leaking. In addition, a sealing ring is arranged at the joint of the bottle opening plug and the gas bottle for sealing, so that gas leakage is prevented. The invention can ensure that the data transmission lines of the temperature sensors distributed in the gas cylinder are well sealed at the cylinder opening in the gas charging process of the gas cylinder.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural view of a high-pressure gas cylinder sealing structure of the present invention mounted on a gas cylinder 16;

FIG. 2 is a cross-sectional view taken along the line C-C in FIG. 1;

FIG. 3 is a cross-sectional view taken in the direction D-D of FIG. 1;

FIG. 4 is a schematic view of the construction of the stopper 7 of FIG. 1;

fig. 5 is a schematic structural view of the cap 1 in fig. 1;

fig. 6 is a schematic view of the structure of the upper cover 2 of fig. 1;

FIG. 7 is a schematic structural view of the lower seal retainer 6 of FIG. 1;

fig. 8 is a schematic view of the cap 1 of fig. 1 in cooperation with the stopper 7.

Detailed Description

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto.

Embodiment 1, a device for measuring the internal temperature of a high-pressure gas cylinder, as shown in fig. 1, is used for measuring a gas cylinder 16, and comprises a cap 1, an upper gland 2, a sealing wedge 3, a large sealing ring 4, a small sealing ring 5, a lower sealing seat 6, a cylinder mouth plug 7, a sealing ring 8 and a threading pipe 9.

The bottle neck plug 7 comprises a bottle neck plug first component 71, a bottle neck plug second component 72 and a bottle neck plug third component 73 which are fixedly connected from top to bottom, the bottle neck plug second component 72 is in the shape of a hexagon bolt, and external threads are arranged on the outer side walls of the bottle neck plug first component 71 and the bottle neck plug third component 73; the diameter of the bottle neck plug second assembly 72 is larger than the diameters of the bottle neck plug first assembly 71 and the bottle neck plug third assembly 73, so that a worker can conveniently screw the bottle neck plug 7 through a hexagon bolt (the bottle neck plug second assembly 72).

A bottle opening plug pipe hole 721 is formed in the bottle opening plug first component 71 and the bottle opening plug second component 72, a bottle opening plug fixing hole 731 is formed in the center of the bottom of the bottle opening plug third component 73, internal threads are formed in the inner wall of the bottle opening plug fixing hole 731, and the bottle opening plug pipe hole 721 extends into the bottle opening plug third component 73 to be communicated with the bottle opening plug fixing hole 731. The stopple aperture 721 and the stopple securing aperture 731 collectively extend through the top and bottom of the stopple 7.

The orifice-plug tube hole 721 and the orifice-plug fixing hole 731 are both located on the central axis of the orifice plug 7, and the diameter of the orifice-plug fixing hole 731 is larger than that of the orifice-plug tube hole 721.

The side wall of the cylinder plug second assembly 72 is further provided with an inflation port 722 communicated with the cylinder plug hole 721, and the air cylinder 16 can be inflated and deflated through the inflation port 722.

The internal thread is arranged on the inner side of the opening of the gas cylinder 16, the third bottle opening plug component 73 is in threaded connection with the gas cylinder 16, a sealing ring 8 is further arranged on the outer side wall of the third bottle opening plug component 73, the sealing ring 8 is located below the external thread on the outer side wall of the third bottle opening plug component 73, and the sealing ring 8 is tightly attached to the opening of the gas cylinder 16 and used for sealing the gas cylinder 16.

A cap fixing cavity 1001 is formed in the bottom of the cap 1, steps 1002 are arranged on the periphery of the top of the cap fixing cavity 1001, and internal threads are formed in the bottom of the inner side wall of the cap fixing cavity 1001; the cap 1 is opened at the top with an outlet 1004 communicating with the cap fixing chamber 1001.

The first bottle neck plug component 71 is in threaded connection with a cap fixing cavity 1001 of the cap 1, and an upper gland 2, a sealing wedge 3 and a lower sealing seat 6 are sequentially arranged between the bottom of the step 1002 and the top of the first bottle neck plug component 71 in a pressing mode from top to bottom. The step 1002 is provided with a clamping table 1003, and the upper gland 2 is embedded into the clamping table 1003 for fixing.

Go up gland 2 and lower seal receptacle 6 and be provided with corresponding last gland wire hole 21 and lower seal receptacle wire hole 61, go up gland wire hole 21 and lower seal receptacle wire hole 61 and align when using, go up gland 2 and be provided with conical surface 211 around last gland wire hole 21 bottom, lower seal receptacle 6 is provided with lower seal receptacle fixed slot 611 around seal receptacle wire hole 61 top down.

The sealing wedge 3 is frustum-shaped, the bottom of the sealing wedge 3 is embedded in the lower sealing seat fixing groove 611, and the side wall of the sealing wedge 3 is abutted to the conical surface 211, so that when the upper gland 2 and the lower sealing seat 6 are pressed, the sealing wedge 3 is compressed accordingly.

The large sealing ring 4 can be arranged between the upper gland 2 and the lower sealing seat 6, the bottom of the upper gland 2 and the top of the lower sealing seat 6 are provided with the corresponding upper gland groove 22 and the corresponding lower sealing seat first groove 62, the two ends of the large sealing ring 4 are embedded into the upper gland groove 22 and the lower sealing seat first groove 62 respectively, the sealing wedge 3 is positioned on the inner side of the large sealing ring 4, and the large sealing ring 4 plays a sealing role.

The small sealing ring 5 can be arranged between the lower sealing seat 6 and the first bottle opening plug component 71, the corresponding lower sealing seat second groove 63 and the first bottle opening plug component groove 711 are formed in the bottom of the lower sealing seat 6 and the top of the first bottle opening plug component 71, the two ends of the small sealing ring 5 are embedded into the lower sealing seat second groove 63 and the first bottle opening plug component groove 711 respectively, the sealing wedge 3 and the bottle opening plug tube hole 721 are located in the small sealing ring 5, and the small sealing ring 5 plays a sealing role.

The sealing tank 8 is made of nitrile rubber, and the sealing wedge 3, the large sealing ring 4, the small sealing ring 5 and the like can all be made of polytetrafluoroethylene, so that a good sealing effect is ensured.

The bottom of the lower sealing seat 6 is provided with annular lower sealing seat bulges 64 around, and the top of the first bottle neck plug component 71 is embedded into the lower sealing seat bulges 64 for fixation.

The 9 lateral wall tops of threading pipe are provided with the external screw thread, and 9 tops of threading pipe and bottleneck stopper fixed orifices 731 threaded connection, during the use, in 9 tops screw in bottleneck stopper fixed orifices 731 of threading pipe, until reaching bottleneck stopper fixed orifices 731 top.

The threading pipe 9 is hollow tubular, the inner cavity of the threading pipe 9 is communicated with the bottleneck plug pipe hole 721, a plurality of threading pipe air inlets 191 are arranged on the side wall of the threading pipe 9 at equal intervals from top to bottom, and inflation is carried out through the threading pipe air inlets 191.

The side wall of the threading pipe 9 is also provided with a plurality of temperature sensors, the temperature sensors are used for collecting temperature data and transmitting the temperature data through a lead, the lead passes through the wire pipe air inlet 191, the inner cavity of the threading pipe 9 and the bottle neck plug pipe hole 721, then passes through the upper gland wire outlet 21, the sealing wedge 3 and the lower sealing seat wire outlet 61, and is led out from the wire outlet 1004 to be connected with a data acquisition card, so that analog signals collected by the temperature sensors are converted into temperature data for storage.

Concerns the sealing of the leads at the mouth of the bottle. After the cap 1 and the bottleneck plug 7 are screwed tightly through threads, the upper gland 2 is pressed downwards, the sealing wedge 3 with the lead is penetrated through by the conical surface 211 on the upper gland 2 for extrusion sealing, and good sealing around the lead is ensured. Meanwhile, the large sealing ring 4 between the upper gland 2 and the lower sealing seat 6 and the small sealing ring 5 between the lower sealing seat 6 and the bottle mouth plug 7 are also extruded and sealed, so that the high-pressure gas in the bottle is prevented from leaking. In addition, a sealing ring 8 is arranged at the joint of the bottle opening plug 7 and the gas bottle 16 for sealing, so that gas leakage is prevented.

Finally, it is also noted that the above-mentioned lists merely illustrate a few specific embodiments of the invention. It is obvious that the invention is not limited to the above embodiments, but that many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.