阅读说明：本技术 排气阀组件、压缩机和空调器 (Exhaust valve assembly, compressor and air conditioner ) 是由 邹鹏 莫宗林 万鹏凯 任丽萍 苏永强 于 2021-10-22 设计创作，主要内容包括：本申请提供一种排气阀组件、压缩机和空调器。该排气阀组件包括法兰(1)和排气组件,法兰(1)设置有阀座(2),阀座(2)设置有排气槽(6),排气槽(6)的底部设置有排气口(3),排气组件设置在阀座(2)上,排气组件包括能够封闭排气口(3)的阀片(4),排气槽(6)内设置有排气阀垫片(7),排气阀垫片(7)由阻尼材料制成,排气阀垫片(7)的结构与排气槽(6)适配,排气阀垫片(7)上对应排气口(3)设置有冷媒流通孔(5),排气阀垫片(7)的高度与设置阀片(4)的安装面高度齐平或者高于设置阀片(4)的安装面高度。根据本申请的排气阀组件,能够更加有效地减小阀片关闭时拍击阀座的作用力,降低压缩机噪声。(The application provides a discharge valve subassembly, compressor and air conditioner. This discharge valve subassembly includes flange (1) and exhaust subassembly, flange (1) is provided with disk seat (2), disk seat (2) are provided with air discharge duct (6), the bottom of air discharge duct (6) is provided with gas vent (3), the exhaust subassembly sets up on disk seat (2), the exhaust subassembly is including valve block (4) that can seal gas vent (3), be provided with exhaust valve gasket (7) in air discharge duct (6), exhaust valve gasket (7) are made by damping material, the structure and air discharge duct (6) adaptation of exhaust valve gasket (7), it is provided with refrigerant circulation hole (5) to correspond gas vent (3) on exhaust valve gasket (7), the height of exhaust valve gasket (7) highly flushes or is higher than the installation face height that sets up valve block (4) with the installation face height that sets up valve block (4). According to the exhaust valve component, the acting force of the slapping valve seat when the valve plate is closed can be effectively reduced, and the noise of the compressor is reduced.)

1. An exhaust valve assembly, characterized in that it comprises a flange (1) and an exhaust assembly, the flange (1) is provided with a valve seat (2), the valve seat (2) is provided with an exhaust groove (6), the bottom of the exhaust groove (6) is provided with an exhaust port (3), the exhaust component is arranged on the valve seat (2), the exhaust assembly comprises a valve plate (4) capable of closing the exhaust port (3), an exhaust valve gasket (7) is arranged in the exhaust groove (6), the exhaust valve gasket (7) is made of damping material, the structure of the exhaust valve gasket (7) is matched with the exhaust groove (6), the exhaust valve gasket (7) is provided with a refrigerant circulation hole (5) corresponding to the exhaust port (3), the height of the exhaust valve gasket (7) is flush with the height of the installation surface provided with the valve plate (4) or higher than the height of the installation surface provided with the valve plate (4).

2. The discharge valve assembly according to claim 1, wherein the refrigerant circulation holes (5) are provided in one-to-one correspondence with the discharge ports (3), and the refrigerant circulation holes (5) have a diameter larger than a diameter of the discharge ports (3) corresponding thereto.

3. A vent valve assembly according to claim 1, wherein the vent valve gasket (7) is adhesively secured within the vent groove (6).

4. The exhaust valve assembly according to claim 1, wherein the exhaust port (3) is circumferentially provided with an annular protrusion (8), and the exhaust valve gasket (7) is supported on the annular protrusion (8) and forms a cavity with the bottom wall of the exhaust groove (6).

5. The vent valve assembly according to claim 4, wherein the vent valve gasket (7) is fixedly mounted on the bottom wall of the vent groove (6) by a screw or a rivet, the annular protrusion (8) is arranged on the periphery of the threaded hole of the vent groove (6), and the heights of the annular protrusions (8) are the same.

6. An exhaust valve assembly according to claim 1, characterized in that the exhaust valve gasket (7) is provided with a damping ring (9) on a side of the refrigerant circulation hole (5) circumference facing the valve plate (4), and a damping ratio of the damping ring (9) is larger than a damping ratio of the exhaust valve gasket (7).

7. The exhaust valve assembly according to claim 6, wherein an annular groove (10) is formed around the refrigerant circulation hole (5) of the exhaust valve gasket (7), and the damping ring (9) is installed in the annular groove (10).

8. An exhaust valve assembly according to claim 6, characterized in that the structural strength of the exhaust valve gasket (7) is greater than the structural strength of the damping ring (9).

9. The discharge valve assembly according to claim 1, wherein the discharge valve gasket (7) is provided with a vibration reduction groove (11) on a side of a refrigerant circulation hole (5) facing the valve sheet (4), and the vibration reduction groove (11) has a predetermined interval from the refrigerant circulation hole (5).

10. The exhaust valve assembly according to claim 1, wherein the exhaust valve gasket (7) is provided with circumferentially extending holes (12) and radially extending holes (13) around the refrigerant flow holes (5), and the circumferentially extending holes (12) and the radially extending holes (13) are alternately arranged and spaced apart in the circumferential direction.

11. An exhaust valve assembly according to claim 1, characterized in that at least one side surface of the exhaust valve gasket (7) is coated with a vibration damping coating (14).

12. The exhaust valve assembly according to claim 1, characterized in that the exhaust ports (3) are at least two and are arranged at intervals in sequence along the rotation direction of the crankshaft, the exhaust valve gasket (7) is of a stepped structure, each exhaust port (3) corresponds to one step height, and the step heights of the exhaust valve gasket (7) are gradually increased along the rotation direction of the crankshaft.

13. A compressor comprising a discharge valve assembly according to any one of claims 1 to 12.

14. An air conditioner including a discharge valve assembly as claimed in any one of claims 1 to 12.

Technical Field

The application relates to the technical field of compressors, in particular to an exhaust valve assembly, a compressor and an air conditioner.

Background

The exhaust component of the rotary compressor is usually composed of a baffle, a valve plate, a rivet, an exhaust valve seat and the like, the valve plate and the valve seat are made of metal materials, when the compressor runs, high-pressure gas reaches condensation pressure, the valve plate is pushed away through an exhaust port to exhaust outwards, after the exhaust is completed, the valve plate swings downwards quickly to close the exhaust port, at the moment, the valve plate slaps the valve seat to generate large slapping force easily, and therefore large mechanical noise is formed, the noise of the compressor exceeds a test standard, and the tone quality is poor.

The exhaust structure of the rotor compressor is characterized in that a seat ring made of non-metallic materials is arranged on a valve seat, so that a valve plate directly slaps on the seat ring to buffer and damp, the seal between the seat ring and the valve plate is changed from rigid seal into soft seal, the sealing effect is better, the service life of the valve plate can be prolonged, and the noise generated during the operation of the compressor is reduced.

Disclosure of Invention

Therefore, the technical problem that this application will be solved lies in providing a discharge valve subassembly, compressor and air conditioner, can reduce the effort of slapping the disk seat when the valve block is closed more effectively, reduces compressor noise.

In order to solve the problem, the application provides a discharge valve subassembly, flange and discharge assembly, the flange is provided with the disk seat, the disk seat is provided with the air discharge duct, the bottom of air discharge duct is provided with the gas vent, the discharge assembly sets up on the disk seat, the discharge assembly is including the valve block that can seal the gas vent, be provided with the discharge valve gasket in the air discharge duct, the discharge valve gasket is made by damping material, the structure and the air discharge duct adaptation of discharge valve gasket, it is provided with the refrigerant circulation hole to correspond the gas vent on the discharge valve gasket, the height of discharge valve gasket highly flushes or is higher than the installation face height that sets up the valve block with the installation face that sets up the valve block.

Preferably, the refrigerant circulation holes and the exhaust ports are arranged in one-to-one correspondence, and the diameter of the refrigerant circulation hole is larger than that of the corresponding exhaust port.

Preferably, the vent valve gasket is adhesively secured within the vent slot.

Preferably, the periphery of the exhaust port is provided with an annular bulge, and the exhaust valve gasket is supported on the annular bulge and forms a cavity with the bottom wall of the exhaust groove.

Preferably, the exhaust valve gasket is fixedly installed on the bottom wall of the exhaust groove through screws or rivets, annular protrusions are arranged on the periphery side of the threaded hole of the exhaust groove, and the heights of the annular protrusions are the same.

Preferably, the exhaust valve gasket is provided with a damping ring on a side of the refrigerant circulation hole circumference facing the valve sheet, and a damping ratio of the damping ring is greater than a damping ratio of the exhaust valve gasket.

Preferably, an annular groove is formed on the periphery of the refrigerant circulation hole of the exhaust valve gasket, and the damping ring is installed in the annular groove.

Preferably, the exhaust valve gasket has a structural strength greater than that of the damping ring.

Preferably, the exhaust valve gasket is provided with a vibration reduction groove on a periphery side of the refrigerant circulation hole facing the valve sheet, and a predetermined interval is provided between the vibration reduction groove and the refrigerant circulation hole.

Preferably, a circumferentially extending hole and a radially extending hole are formed around the refrigerant flow hole of the exhaust valve gasket, and the circumferentially extending hole and the radially extending hole are alternately arranged and spaced in the circumferential direction.

Preferably, at least one side surface of the exhaust valve gasket is coated with a vibration damping coating.

Preferably, the exhaust port is at least two, and along the rotation direction of bent axle interval setting in proper order, and the exhaust valve gasket is ladder structure, and every exhaust port corresponds a step height, and along the rotation direction of bent axle, the step height of exhaust valve gasket increases progressively.

According to another aspect of the present application, there is provided a compressor comprising a discharge valve assembly as described above.

According to another aspect of the present application, there is provided an air conditioner including a discharge valve assembly as described above.

The application provides an exhaust valve subassembly, flange and exhaust subassembly, the flange is provided with the disk seat, the disk seat is provided with the air discharge duct, the bottom of air discharge duct is provided with the gas vent, exhaust subassembly sets up on the disk seat, exhaust subassembly is including the valve block that can seal the gas vent, be provided with the exhaust valve gasket in the air discharge duct, the exhaust valve gasket is made by damping material, the structure and the air discharge duct adaptation of exhaust valve gasket, it is provided with the refrigerant circulation hole to correspond the gas vent on the exhaust valve gasket, the high installation face height that highly flushes or is higher than the installation face height that sets up the valve block with the installation face that sets up the valve block of exhaust valve gasket. The exhaust valve assembly is characterized in that an exhaust valve gasket is laid in an exhaust groove of a valve seat, so that the surface of the whole exhaust groove of the valve seat is covered by the exhaust valve gasket, in the process that a valve plate slaps the valve seat, the valve plate cannot directly slap the surface of the exhaust groove and can directly slap the exhaust valve gasket, and the exhaust valve gasket is made of damping materials, so that the energy of the valve plate slap the valve seat can be absorbed by utilizing the damping characteristic.

Drawings

FIG. 1 is a schematic structural view of a vent valve assembly according to an embodiment of the present application;

FIG. 2 is an enlarged schematic view of FIG. 1 at L;

FIG. 3 is an exploded view of a vent valve assembly according to an embodiment of the present application;

FIG. 4 is a schematic illustration of a vent valve gasket of a vent valve assembly according to an embodiment of the present application;

FIG. 5 is an exploded view of a vent valve assembly according to an embodiment of the present application;

FIG. 6 is a schematic view of a vent valve gasket of a vent valve assembly according to an embodiment of the present application;

FIG. 7 is an exploded view of a vent valve assembly according to an embodiment of the present application;

FIG. 8 is a schematic view of a vent valve gasket of a vent valve assembly according to an embodiment of the present application;

FIG. 9 is a cross-sectional view of the exhaust valve gasket of FIG. 8 taken along line A-A;

FIG. 10 is a schematic view of a vent valve gasket of a vent valve assembly according to an embodiment of the present application;

FIG. 11 is a cross-sectional view of the exhaust valve gasket of FIG. 10 taken along line B-B;

FIG. 12 is a schematic view of a vent valve gasket of a vent valve assembly according to an embodiment of the present application;

FIG. 13 is a schematic view of a vent valve gasket of a vent valve assembly in accordance with an embodiment of the present application;

FIG. 14 is a schematic view of a vent valve gasket of a vent valve assembly according to an embodiment of the present application;

fig. 15 is a graph of operating frequency versus noise for a compressor according to an embodiment of the present application and a related art compressor.

The reference numerals are represented as:

1. a flange; 2. a valve seat; 3. an exhaust port; 4. a valve plate; 5. a refrigerant circulation hole; 6. an exhaust groove; 7. an exhaust valve gasket; 8. an annular projection; 9. a damping ring; 10. an annular groove; 11. a vibration damping tank; 12. a circumferentially extending bore; 13. a radially extending bore; 14. a vibration damping coating; 15. a lift limiter.

Detailed Description

Referring to fig. 1-15 in combination, according to the embodiment of this application, the discharge valve subassembly includes flange 1 and exhaust subassembly, flange 1 is provided with disk seat 2, disk seat 2 is provided with exhaust duct 6, the bottom of exhaust duct 6 is provided with gas vent 3, the exhaust subassembly sets up on disk seat 2, the exhaust subassembly is including the valve block 4 that can seal gas vent 3, be provided with exhaust valve gasket 7 in the exhaust duct 6, exhaust valve gasket 7 is made by damping material, the structure and the 6 adaptations of exhaust duct of exhaust valve gasket 7, it is provided with refrigerant circulation hole 5 to correspond gas vent 3 on the exhaust valve gasket 7, the height of exhaust valve gasket 7 highly flushes or is higher than the installation face height that sets up valve block 4 with the installation face height that sets up valve block 4.

The exhaust valve component is characterized in that an exhaust valve gasket 7 is laid in an exhaust groove 6 of a valve seat 2, so that the surface of the whole exhaust groove 6 of the valve seat 2 is covered by the exhaust valve gasket 7, in the process that a valve plate 4 flaps the valve seat 2, the valve plate 4 cannot flap the surface of the exhaust groove 6 directly and can flap the exhaust valve gasket 7 directly, and the exhaust valve gasket 7 is made of damping material, so that the energy of the valve plate 4 for flapping the valve seat 2 can be absorbed by utilizing the damping characteristic of the exhaust valve gasket 7, because the exhaust valve gasket 7 is laid on the whole exhaust groove 6, the contact area with the valve plate 4 is larger, and the valve plate 4 basically and completely flaps the exhaust valve gasket 7, the exhaust valve gasket 7 has stronger capacity of absorbing the energy of the valve plate 4 for flapping the valve seat 2, the acting force of the valve plate 4 for flapping the valve seat 2 when the valve plate 4 is closed can be reduced more effectively, the impact of the valve plate 4 on the valve seat 2 is reduced, and the valve plate 4 and the valve seat 2 are effectively protected, the service life of the lift valve plate 4 and the reliability of the compressor are prolonged, and the noise of the compressor is reduced.

In one embodiment, the exhaust valve gasket 7 may be made of PA, POM, Mn — Cu alloy, or other flexible valve sheet materials, which may have a better damping effect.

The discharge valve subassembly of this embodiment can be applicable to on all kinds of compressors, air compressor machine, and the suitability is good, and the range of application is wide.

The exhaust valve assembly is particularly suitable for sliding vane compressors, and can also be suitable for rotor compressors and scroll compressors.

In one embodiment, the refrigerant circulation holes 5 are disposed in one-to-one correspondence with the exhaust ports 3, and the diameter of the refrigerant circulation hole 5 is larger than the diameter of the corresponding exhaust port 3. In this embodiment, the diameter of the refrigerant circulation hole 5 is larger than the diameter of the exhaust port 3, so that the refrigerant circulation hole 5 does not block the exhaust port 3 and does not obstruct the normal flow of the refrigerant. The cross-sectional shape of the refrigerant circulation hole 5 may be circular, rhombic, parallelogram or other shapes, and in any shape, the exhaust port 3 needs to be completely opened, that is, the projection of the exhaust port 3 is completely located in the projection of the refrigerant circulation hole 5 on the plane perpendicular to the central axis of the exhaust port 3.

In one embodiment, the vent valve gasket 7 is adhesively secured within the vent slot 6. The exhaust valve gasket 7 can also be fixedly arranged in the exhaust groove 6 through screws or rivets and the like, so that the exhaust valve gasket 7 can be prevented from moving along with the valve plate 4 in the moving process of the valve plate 4, and the vibration reduction effect of the exhaust valve gasket 7 is improved.

The exhaust valve gasket 7 may be C-shaped or elongated and should have a shape corresponding to the shape of the exhaust groove 6 to ensure that the exhaust valve gasket 7 fills the entire exhaust groove 6, so that the slapping force of the valve plate 4 acts substantially completely on the exhaust valve gasket 7 and not on the valve seat 2.

For the exhaust valve component with a single exhaust port 3, the exhaust valve gasket 7 can adopt a uniform thickness, and for the exhaust valve component with non-single exhaust ports 3, the exhaust valve gasket 7 can adopt a uniform thickness, preferably an uneven thickness, and the thickness of the exhaust valve gasket 7 should be adapted to the exhaust pressure of the exhaust port 3 where the exhaust valve gasket 7 is located, and the larger the exhaust pressure is, the larger the thickness of the exhaust valve gasket 7 is, so that the exhaust valve gasket can be matched with the slapping action of the valve plate 4, and better damping action is generated.

In one embodiment, the exhaust valve assembly further comprises a lift limiter 15 for limiting the lift of the valve plate 4. When the valve plate 4 is opened, the valve plate 4 warps upwards around the lift limiter 15, and the lift limiter 15 plays a role in limiting the opening height of the valve plate 4, so that the valve plate 4 can be prevented from being opened to an excessively large extent under the condition of no opening limitation, and the fatigue life of the valve plate 4 is shortened. The valve plate 4 and the lift limiter 15 are sequentially placed on the valve seat 2 from bottom to top and are fixed on the valve seat 2 through rivets or screws.

In one embodiment, the exhaust port 3 is circumferentially provided with an annular protrusion 8, and the exhaust valve gasket 7 is supported on the annular protrusion 8 and forms a cavity with the bottom wall of the exhaust groove 6.

The exhaust valve gasket 7 is fixedly installed on the bottom wall of the exhaust groove 6 through screws or rivets, annular protrusions 8 are arranged on the periphery of the threaded hole of the exhaust groove 6, and the heights of the annular protrusions 8 are the same.

In this embodiment, two screw holes are added to the exhaust valve gasket 7, and screw holes are also added to the corresponding positions on the bottom of the exhaust groove 6, so that the exhaust valve gasket 7 can be fixed to the bottom wall of the exhaust groove 6 by using screws. The exhaust port 3 and the peripheral sides of the screw holes are provided with annular protrusions 8, so that a cavity is formed between the exhaust valve gasket 7 and the bottom wall of the exhaust groove 6, the deformation of the exhaust valve gasket 7 is increased, and the vibration reduction effect is improved.

In one embodiment, the discharge valve gasket 7 is provided with a damping ring 9 on the side of the refrigerant circulation hole 5 toward the valve sheet 4, and the damping ratio of the damping ring 9 is larger than that of the discharge valve gasket 7.

An annular groove 10 is arranged on the periphery of the refrigerant circulation hole 5 of the exhaust valve gasket 7, and a damping ring 9 is arranged in the annular groove 10.

In the embodiment, the annular groove 10 of the exhaust valve gasket 7 is filled with the damping ring 9 for buffering, wherein the damping ring 9 is made of PA, Mn — Cu alloy, thin steel sheet or other flexible materials, and has a better damping effect compared with other rigid materials. The damping ring 9 filled in the annular groove 10 can be filled by selecting different materials according to the stress condition of the flapping part, flexible materials such as PA and the like are adopted at the part with larger stress, and metal materials such as Mu-Cu alloy and the like are adopted at the part with smaller stress. Specifically, the stress is gradually reduced from the center of the exhaust port 3 to the outside, the position with the larger stress of the inner ring is made of PA material, and the position with the smaller stress of the outer ring is made of Mu-Cu alloy.

In this embodiment, the damping ratio of the damping ring 9 is greater than that of the exhaust valve gasket 7, and it can be ensured that a damping material with a higher damping ratio is adopted at the position where the circumferential side of the exhaust port 3 is most slapped by the valve sheet 4, so that the slapping force of the valve sheet 4 can be absorbed more effectively, and a better vibration and noise reduction effect is achieved.

In one embodiment, the structural strength of the exhaust valve gasket 7 is greater than the structural strength of the damping ring 9. In the present embodiment, since the area of the exhaust valve gasket 7 is large, in order to improve the durability of the exhaust valve gasket 7, the structural strength of the exhaust valve gasket 7 may be made larger than that of the damping ring 9, thereby balancing the relationship between the areas and the structural strength of the two.

In one embodiment, the discharge valve gasket 7 is provided with a damper groove 11 on a side of the refrigerant circulation hole 5 toward the valve sheet 4, and the damper groove 11 is spaced from the refrigerant circulation hole 5 by a predetermined distance. In this embodiment, the damper groove 11 is provided on the periphery of the refrigerant flow hole 5 of the exhaust valve gasket 7, and the damper groove 11 is, for example, annular, so that when the valve sheet 4 moves downward to slap the exhaust valve gasket 7, the damper groove 11 can form a certain air pressure, thereby performing a function of buffering and damping vibration.

In one embodiment, the circumferential side of the refrigerant circulation hole 5 of the exhaust valve gasket 7 is provided with a circumferentially extending hole 12 and a radially extending hole 13, and the circumferentially extending hole 12 and the radially extending hole 13 are alternately arranged and spaced in the circumferential direction, so that a flexible vibration damping structure can be formed around the exhaust port 3, the deformation of the exhaust valve gasket 7 can be further increased, and the slapping energy of the valve plate 4 can be better absorbed.

In one embodiment, at least one side surface of the exhaust valve gasket 7 is coated with a vibration damping coating 14. In the present embodiment, the vibration damping coating 14 is, for example, graphite, PTFE, or the like, and thus the vibration damping capability of the exhaust valve gasket 7 can be further enhanced, and the slapping force of the valve sheet 4 can be reduced.

In one embodiment, the number of the exhaust ports 3 is at least two, and the exhaust valve gaskets 7 are arranged at intervals in sequence along the rotation direction of the crankshaft, each exhaust port 3 corresponds to a step height, and the step heights of the exhaust valve gaskets 7 are gradually increased along the rotation direction of the crankshaft.

In this embodiment, take the bottom of the exhaust duct 6 to set up three exhaust ports 3 as an example, the exhaust valve gasket 7 adopts the unequal thickness structure of stairstepping, three steps have, along the direction of rotation of the crankshaft, the height of three steps is H1, H2 and H3 respectively, because the refrigerant velocity of three exhaust ports 3 is inequality, the speed that leads to valve block 4 to slap exhaust valve gasket 7 is inequality, consequently, in order to make the damping capacity of exhaust valve gasket 7 match with the speed that valve block 4 slaps exhaust valve gasket 7, can adopt thin material in the position that the atress is little, adopt thick material in the position that the atress is big, make H1 > H2 > H3, thereby through adopting the exhaust valve gasket 7 of unequal thickness in order to reach better damping effect.

Referring to fig. 15 in combination, after the exhaust valve assembly of the embodiment of the present application is adopted, the noise of the compressor can be reduced within a range of 25 to 50Hz, and a significant noise reduction effect is achieved within a range of 35 to 45 Hz.

In this embodiment, taking a sliding vane compressor as an example, a compressor pump body is composed of an exhaust valve assembly, an upper flange, a roller, a crankshaft, a sliding vane, a cylinder and a lower flange, and the air suction, compression and exhaust operations of the compressor are completed together, a closed cavity is formed between the upper flange, the cylinder and the lower flange, the crankshaft rotates to drive the sliding vane to reciprocate in the cylinder to change the volume of the cavity so as to achieve the purpose of compressing air, when a refrigerant is compressed to a certain pressure, high-pressure air can push open a valve plate 4 in the exhaust assembly through an exhaust port 3 to exhaust, and when the exhaust is finished, the valve plate 4 moves downwards due to the action of pressure difference and self elastic deformation force to close the exhaust port 3, so that the whole compression and exhaust operations are completed.

In the operation process of the compressor, the valve plate 4 can do periodic opening and closing movement, when the valve plate 4 is closed, the head of the valve plate 4 moves downwards to flap on the exhaust valve gasket 7, and the exhaust valve gasket 7 is made of flexible damping materials, so that the exhaust valve gasket 7 can deform to different degrees under the action of flap force, and an effective buffering and vibration damping effect can be achieved.

According to an embodiment of the present application, the compressor comprises a discharge valve assembly, which is the discharge valve assembly described above.

According to an embodiment of the present application, an air conditioner includes a discharge valve assembly, which is the discharge valve assembly described above.

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.