阅读说明：本技术 分离结构及具有该分离结构的潜油电泵机组用排砂装置 (Separation structure and sand discharge device with same for electric submersible pump unit ) 是由 白建平 武荻皓 曲丽峰 白山 曲方舟 曾林锁 李磊 颜伟 于 2020-06-09 设计创作，主要内容包括：本发明适用于机械领域,提供了一种分离结构及具有该分离结构的潜油电泵机组用排砂装置,所述分离结构包括用于与驱动机构连接的保护器,保护器一端与连接节连接,连接节内设有套设在驱动轴外侧的排砂件,在驱动轴转动时带动排砂件绕驱动轴的轴心线进行转动,以将进入至连接节内的井液中的杂质进行分离,连接节外侧设有用于排出杂质的排砂孔。本发明通过排砂件将进入至连接节内的井液中的杂质进行分离,再通过排砂孔排出至连接节外部,通过排砂件的分离作业可以减少杂质堆积在连接节与保护器的连接处,有效保证了密封性能,解决了现有潜油电泵在工作中存在井液中的杂质易发生沉积并影响密封性能的问题。(The invention is suitable for the field of machinery and provides a separation structure and a sand discharge device for an electric submersible pump unit with the same, wherein the separation structure comprises a protector used for being connected with a driving mechanism, one end of the protector is connected with a connecting joint, a sand discharge piece sleeved outside a driving shaft is arranged in the connecting joint, the sand discharge piece is driven to rotate around the axial lead of the driving shaft when the driving shaft rotates, so that impurities in well fluid entering the connecting joint are separated, and a sand discharge hole used for discharging the impurities is arranged outside the connecting joint. According to the invention, impurities in well fluid entering the connecting joint are separated through the sand discharging piece and then discharged to the outside of the connecting joint through the sand discharging hole, and the impurities accumulated at the connecting part of the connecting joint and the protector can be reduced through the separation operation of the sand discharging piece, so that the sealing performance is effectively ensured, and the problem that the impurities in the well fluid are easy to deposit and influence the sealing performance in the operation of the existing electric submersible pump is solved.)

1. The utility model provides a separation structure, includes the protector that is used for being connected with actuating mechanism, protector one end is connected with the connecting link that is used for supplying well liquid transmission, the connecting link is kept away from the one end of protector is provided with the opening, its characterized in that, separation structure still includes:

the sand discharge piece is arranged in the connecting joint, the output end of the driving mechanism is connected with a driving shaft arranged at the axis of the connecting joint and used for driving the driving shaft to rotate under the driving of the driving mechanism, and the sand discharge piece is sleeved outside the driving shaft and used for driving the sand discharge piece to rotate around the axis of the driving shaft when the driving shaft rotates so as to separate impurities in well fluid entering the connecting joint; and

and the sand discharge hole is arranged on the outer side of the connecting joint and is used for communicating with the part, corresponding to the sand discharge piece, inside the connecting joint so that the sand discharge piece can enter the connecting joint and discharge impurities in the well fluid in the connecting joint after separation.

2. The separation structure according to claim 1, wherein the plurality of the sand discharge holes are uniformly arranged outside the connecting joint in a circular array, and one end of the sand discharge hole facing the driving shaft is positioned outside the sand discharge member.

3. The separation structure of claim 1, wherein the sand ejector comprises:

the sand discharging part main body is arranged on the driving shaft, and a second mounting hole for the driving shaft to pass through is formed in the axis of the sand discharging part main body; and

and the blades are arranged on the outer side of the sand discharging part main body and are used for generating centrifugal force under the driving of the driving shaft so as to separate impurities in the well fluid entering the connecting joint.

4. The separation structure of claim 3, wherein the number of the blades is multiple, the blades are uniformly arranged outside the sand discharge part main body in a circular array, one side edge of each blade facing the sand discharge hole is obliquely arranged with the driving shaft, and the included angle of the inclination is 10-80 degrees.

5. The separation structure of claim 4, wherein the blades are triangular structures, four blades are arranged, and are uniformly arranged outside the sand discharge part main body in a circular array, the inclined edges of the triangular structures are obliquely arranged with the driving shaft, and the inclined angle is 20-50 degrees.

6. The separation structure of claim 3, wherein a plurality of first mounting holes are correspondingly formed in the sand discharge member main body, the first mounting holes are used for mounting a connecting member, and the connecting member is used for detachably connecting the sand discharge member with the driving shaft.

7. A sand discharge device for an electric submersible pump unit, comprising the separation structure according to any one of claims 1 to 6, wherein the sand discharge device for an electric submersible pump unit further comprises: the bearing support seat is arranged at the inner part of a connecting joint between the sand discharging piece and the protector, and a bearing which is used for limiting the driving shaft to rotate around the axial lead of the driving shaft and does not deviate is arranged on the bearing support seat.

8. The sand discharge device for an electric submersible pump unit according to claim 7, wherein the protector is further provided with a sealing portion at an end facing the connecting joint for isolating well fluid to prevent the well fluid from entering the driving mechanism.

9. The electrical submersible pump unit sand discharge device according to claim 8, wherein the sealing portion comprises:

the cavity is arranged on the connecting joint part corresponding to the connecting part of the connecting joint and the protector; and

and the mechanical seal is arranged in the cavity, and a protective medium is injected into the cavity and used for isolating well liquid.

10. The sand discharge device for the electrical submersible pump unit according to claim 7, wherein a plurality of oil holes are further provided in the bearing support base.

Technical Field

The invention belongs to the field of machinery, and particularly relates to a separation structure and a sand discharge device for an electric submersible pump unit with the same.

Background

At present, an electric submersible pump is generally used in oil extraction operation, and the electric submersible pump is used as important mechanical oil extraction equipment, generally a multistage centrifugal pump working underground, and is put into a well together with an oil pipe, and the multistage centrifugal pump is driven to rotate by the electric submersible pump, so that well fluid in the well is lifted to the ground.

The protector of the electric submersible pump has important significance for normal work of the electric submersible pump. The protector is mainly used for isolating motor oil and well fluid, so that the driving mechanisms such as the motor can not only run in an oil well and have enough motor oil to provide lubrication, but also can seal the motor and prevent the well fluid from entering the motor.

In the process of utilizing the electric submersible pump to recover oil at the present stage, impurities such as sand and stone, oil sludge and the like are often deposited at the mechanical seal position at the end part of the protector, and are very easy to accumulate in a gap of a waveform of the mechanical seal, so that the mechanical seal is blocked to lose elasticity, the mechanical seal is caused to lose efficacy, and a large amount of leakage is caused. Therefore, the above technical solution also has the following disadvantages in practical use: the existing electric submersible pump has the problem that impurities in well fluid are easy to deposit during working, so that the sealing performance is affected.

Disclosure of Invention

An object of an embodiment of the present invention is to provide a separation structure, so as to solve the problem that impurities in well fluid are easily deposited and affect the sealing performance in the operation of the existing electrical submersible pump in the background art.

The embodiment of the invention is realized in such a way that a separation structure comprises a protector used for being connected with a driving mechanism, one end of the protector is connected with a connecting joint used for well fluid transmission, and one end of the connecting joint far away from the protector is provided with an opening, and the separation structure is characterized by further comprising:

the sand discharge piece is arranged in the connecting joint, the output end of the driving mechanism is connected with a driving shaft arranged at the axis of the connecting joint and used for driving the driving shaft to rotate under the driving of the driving mechanism, and the sand discharge piece is sleeved outside the driving shaft and used for driving the sand discharge piece to rotate around the axis of the driving shaft when the driving shaft rotates so as to separate impurities in well fluid entering the connecting joint; and

and the sand discharge hole is arranged on the outer side of the connecting joint and is used for communicating with the part, corresponding to the sand discharge piece, inside the connecting joint so that the sand discharge piece can enter the connecting joint and discharge impurities in the well fluid in the connecting joint after separation.

In another embodiment of the present invention, there is provided a sand discharge device for an electrical submersible pump unit, including the above separation structure, the sand discharge device for an electrical submersible pump unit further includes: the bearing support seat is arranged at the inner part of a connecting joint between the sand discharging piece and the protector, and a bearing which is used for limiting the driving shaft to rotate around the axial lead of the driving shaft and does not deviate is arranged on the bearing support seat.

Compared with the prior art, the separation structure provided by the embodiment of the invention comprises a protector connected with a driving mechanism, one end of the protector is connected with a connecting joint, a sand discharge piece sleeved outside a driving shaft is arranged in the connecting joint, the output end of the driving mechanism is connected with the driving shaft, the sand discharge piece is driven to rotate around the axial lead of the driving shaft when the driving shaft rotates so as to separate impurities in well fluid entering the connecting joint, a sand discharge hole used for discharging impurities is arranged outside the connecting joint, the impurities in the well fluid entering the connecting joint are separated through the sand discharge piece and then discharged to the outside of the connecting joint through the sand discharge hole, the accumulation of the impurities at the connecting part of the connecting joint and the protector can be reduced through the separation operation of the sand discharge piece, the sealing performance is effectively ensured, the large amount of leakage is avoided, and the problem that the impurities in the well fluid are easy to deposit and affect the sealing performance in the operation of the existing electric submersible pump is solved And (5) problems are solved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention.

Fig. 1 is a schematic structural diagram of a separation structure according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a sand discharge member in a separation structure according to an embodiment of the present invention.

Fig. 3 is a top view of a sand discharge member in a separation structure according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a sand discharge device for an electrical submersible pump unit according to another embodiment of the present invention.

In the figure: 1-a connecting joint; 2-a drive shaft; 3, a sand discharging part; 4-a connector; 5-a bearing; 6-bearing support seat; 7-mechanical sealing; 8-a protector; 9-oil hole; 10-sand drain holes; 11-a first mounting hole; 12-a sand discharge body; 13-a second mounting hole; 14-a blade; 15-opening; 16-a protective medium; 17-a seal; 18-well fluid.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

Specific implementations of the present invention are described in detail below with reference to specific embodiments.

As shown in fig. 1 to 3, a structure diagram of a separation structure provided for an embodiment of the present invention, the separation structure includes a protector 8 for connecting with a driving mechanism (not shown in the drawings), one end of the protector 8 is connected with a connecting joint 1 for transmitting well fluid, an end of the connecting joint 1 away from the protector 8 is provided with an opening 15, and the separation structure further includes:

the sand discharging piece 3 is arranged in the connecting joint 1, the output end of the driving mechanism is connected with the driving shaft 2 arranged at the axis of the connecting joint 1 and used for driving the driving shaft 2 to rotate under the driving of the driving mechanism, and the sand discharging piece 3 is sleeved on the outer side of the driving shaft 2 and used for driving the sand discharging piece 3 to rotate around the axis line of the driving shaft 2 when the driving shaft 2 rotates so as to separate impurities in well fluid entering the connecting joint 1; and

and the sand discharge hole 10 is arranged on the outer side of the connecting joint 1 and is used for communicating with the part, corresponding to the sand discharge piece 3, inside the connecting joint 1 so that the sand discharge piece 3 can enter the connecting joint 1 and discharge impurities in the well fluid after separation, and the impurities in the well fluid are discharged from the connecting joint 1.

In the embodiment of the invention, as the sand discharging piece 3 is arranged, impurities in well fluid entering the connecting joint 1 are separated through the sand discharging piece 3 and then discharged to the outside of the connecting joint 1 through the sand discharging hole 10, and impurities such as sand, oil sludge and the like are easy to deposit when the well fluid such as the well fluid enters the connecting joint 1, so that the impurities are accumulated at the connecting part of the connecting joint 1 and the protector 8, the sealing performance is further influenced, and a large amount of leakage is caused.

In an embodiment of the present invention, specifically, the sand discharging member 3 is mounted on the driving shaft 2 and rotates synchronously with the driving shaft 2, so that a centrifugal force is generated on the well fluid when the sand discharging member 3 rotates, and the heavy solid particle impurities in the well fluid are thrown out in a tilted rear direction under the action of gravity and the centrifugal force and are discharged through the sand discharging hole 10 on the connecting joint 1.

In another example of the present invention, the driving mechanism may be an existing power driving device, for example, a motor in the prior art, and the motor may be a dc motor, an asynchronous motor or a synchronous motor, which is selected according to practical requirements, and is not limited herein, as long as it can drive the driving shaft 2 to rotate; when the separation structure is used for an electric submersible pump unit, correspondingly, the connecting joint 1 can be connected with an oil pipe to be put into a well together, or can be connected with the connecting joints 1 of other electric submersible pumps to form the electric submersible pump unit, a ground power supply transmits electric energy to a driving mechanism (namely an underground electric submersible motor) through the prior art means such as a transformer, a control panel and a power cable, so that the driving mechanism drives the driving shaft 2 to rotate, and then the driving fan blades arranged at the opening 15 of the driving shaft 2 are driven to rotate to convert the electric energy into mechanical energy to lift well fluid in the oil well to the ground, the protector 8 is connected with the driving mechanism, and the motor oil and the well fluid are isolated through the protector 8 to prevent the well fluid from entering the driving mechanism.

Further, as a preferred embodiment of the present invention, the sand discharge holes 10 are a plurality of sand discharge holes, and are uniformly arranged in a circular array outside the connecting joint 1, and one end of the sand discharge hole 10 facing the driving shaft 2 is located outside the sand discharge member 3.

In the embodiment of the invention, the sand discharging piece 3 synchronously rotates along with the driving shaft 2, centrifugal force is generated on well fluid when the sand discharging piece 3 rotates, and solid particle impurities with heavy mass in the well fluid are thrown out in the oblique rear direction under the action of gravity and centrifugal force and then are discharged from the sand discharging holes 10 on the connecting joint 1.

Further, as a preferred embodiment of the present invention, the sand discharging member 3 includes:

the sand discharging part main body 12 is arranged on the driving shaft 2, and a second mounting hole 13 for the driving shaft 2 to pass through is formed in the axis of the sand discharging part main body 12; and

and the blades 14 are arranged outside the sand discharging part main body 12 and are used for generating centrifugal force under the driving of the driving shaft 2 so as to separate impurities in the well fluid entering the connecting joint 1.

In the embodiment of the present invention, the sand discharging body 12 is mounted on the driving shaft 2 through the second mounting hole 13, and at the same time, centrifugal force is generated by the blades 14 driven by the driving shaft 2 to separate impurities in the well fluid introduced into the coupling joint 1.

In an example of the present invention, a specific shape of the blade 14 is selected according to a requirement, for example, the blade may be one of a triangle, a rectangle, a semi-cylinder, or a polygon, and is not particularly limited, but is preferably a triangle, and of course, the above is only some preferred shapes, and the blade 14 may also be other shapes such as a multi-segment line shape, a U shape, and the like, which are set according to a practical requirement and are not limited herein, and of course, in order to clearly and specifically embody the present solution, the blade 14 is mainly embodied in a triangle form in the following embodiments, but is mainly for embodying the feasibility of the solution and is not limited herein.

Further, as a preferred embodiment of the present invention, a plurality of the vanes 14 are arranged, and are uniformly arranged outside the sand discharging member main body 12 in a circular array, and a side edge of one side of the vane 14 facing the sand discharging hole 10 and the driving shaft 2 are arranged in an inclined manner, and the inclined included angle is 10-80 °.

In the embodiment of the invention, the side edge of one side of the blade 14 facing the sand discharge hole 10 is obliquely arranged with the driving shaft 2, so that the rotation of the sand discharge member 3 is matched to enable solid particle impurities with heavy mass in well fluid to be thrown out towards the oblique rear direction under the action of gravity and centrifugal force, and then the solid particle impurities are discharged from the sand discharge hole 10 on the connecting joint 1.

In one embodiment of the present invention, it is preferable that a side edge of the vane 14 facing the sand discharge hole 10 forms an angle of 30 ° with the driving shaft 2.

Further, as a preferred embodiment of the present invention, the number of the blades 14 is four, and the four blades are arranged in a triangular structure and are uniformly arranged outside the sand discharging member main body 12 in a circular array, and the oblique side of the triangular structure and the driving shaft 2 are arranged in an inclined manner, and the inclined angle is 20-50 °.

In the embodiment of the invention, the blades 14 are arranged to be triangular structures, so that heavy solid particle impurities in the well fluid can conveniently move towards the backward direction under the action of gravity.

In an embodiment of the present invention, the sand discharging member body 12 and the blades 14 together form an umbrella structure, and further, the umbrella structure is fixedly mounted on the driving shaft 2, and with the synchronous rotation of the driving shaft 2, the inclined edges of the blades 14 form an included angle of 30 degrees with the driving shaft 2, so that a centrifugal force is generated on the well fluid during rotation, and the heavy solid particle impurities in the well fluid are thrown out in an inclined rear direction under the action of gravity and the centrifugal force and then discharged from the sand discharging holes 10 on the connecting joint 1.

In another embodiment of the present invention, the sand discharging member 3 is made of a wear-resistant and corrosion-resistant nickel cast iron in the prior art, but may be made of other materials according to the requirement, and is not limited herein.

Further, as a preferred embodiment of the present invention, a plurality of first mounting holes 11 are correspondingly formed in the sand discharging member main body 12, the first mounting holes 11 are used for mounting a connecting member 4, and the connecting member 4 is used for detachably connecting the sand discharging member 3 and the driving shaft 2.

In the embodiment of the invention, the sand discharging piece 3 is detachably connected with the driving shaft 2 through the connecting piece 4, so that the sand discharging piece 3 can be detached, replaced or maintained and cleaned according to requirements, and the sand discharging device is simple and convenient.

In an embodiment of the present invention, the connecting member 4 may be an existing connecting structure, for example, a screw, a bolt, a snap, etc. in this embodiment, preferably, the connecting member 4 is a screw. An inner threaded hole matched with the first mounting hole 11 is correspondingly formed in the driving shaft 2, and the sand discharging piece 3 is fixedly mounted on the driving shaft 2 through a jackscrew.

As shown in fig. 4, an embodiment of the present invention further provides a sand discharge device for an electrical submersible pump unit, including the above separation structure, the sand discharge device for an electrical submersible pump unit further includes: and the bearing support seat 6 is arranged at the inner part of the connecting joint 1 between the sand discharging piece 3 and the protector 8, and the bearing support seat 6 is provided with a bearing 5 which is used for limiting the driving shaft 2 to rotate around the axial lead of the driving shaft 2 and does not deviate.

In the embodiment of the invention, the bearing 5 arranged on the bearing support seat 6 limits the rotation of the driving shaft 2 around the axis of the driving shaft 2 and does not deviate.

In one embodiment of the invention, the sand discharging element 3 is installed above the bearing support seat 6, impurities such as sand, oil sludge and the like in the well fluid 18 can be discharged from the sand discharging hole 10 through the sand discharging element 3, and the phenomenon that the impurities such as sand, oil sludge and the like are deposited to cause sealing failure and cause large leakage of motor oil is reduced.

Further, as a preferred embodiment of the present invention, a sealing portion 17 is further provided at an end of the protector 8 facing the connecting joint 1 for isolating well fluid 18 to limit the well fluid 18 from entering the driving mechanism.

In the embodiment of the invention, impurities such as sand, oil sludge and the like are blocked by the sand discharging piece 3 and cannot directly fall into the sealing part 17.

Further, as a preferred embodiment of the present invention, the sealing portion 17 includes:

the cavity is arranged at the part of the connecting joint 1 corresponding to the connecting part of the connecting joint 1 and the protector 8; and

and the mechanical seal 7 is arranged in the cavity, and the cavity is also filled with a protective medium 16 for isolating well fluid 18 so as to protect the mechanical seal 7 from chemical corrosion.

In the embodiment of the invention, the mechanical seal 7 has a sealing effect, impurities such as sand, oil sludge and the like are often deposited at the mechanical seal 7 arranged at the end part of the protector 8, and are very easy to accumulate in a wave-shaped gap of the mechanical seal 7, so that the mechanical seal 7 is clamped to lose elasticity, the mechanical seal 7 fails, a large amount of leakage is caused, impurities in well fluid entering the connecting joint 1 are separated through the sand discharging piece 3, and then the impurities are discharged to the outside of the connecting joint 1 through the sand discharging hole 10; meanwhile, the mechanical seal 7 is arranged inside the cavity, and a protective medium 16 is injected into the cavity to isolate the well fluid 18 so as to protect the mechanical seal 7 from chemical corrosion.

In one embodiment of the present invention, the protective medium 16 may be a product of the prior art, such as a liquid medium or a gas medium, and typically, the liquid medium may be motor oil, water, transformer oil, spindle oil, seal oil, lubricating oil, etc. Preferably, the protective medium 16 is a sealing oil, such as MO series sealing oil of japan pine village petroleum, or huifeng HFV-MF vacuum sealing oil of jiangsu huifeng lubricating material stock ltd, and the specific product is selected according to the requirement, which is not limited herein.

In a preferred embodiment of the present invention, a plurality of oil holes 9 are further formed in the bearing support base 6. In the embodiment of the invention, through the matched use of the protector 8, the sand discharging piece 3 and the oil hole 9, the protector 8 isolates the motor oil from the well fluid 18, and simultaneously, the driving mechanism can not only run in an oil well and have enough motor oil to provide lubrication, but also can seal the driving mechanism and prevent the well fluid 18 from entering the driving mechanism.

In one embodiment of the invention, the oil hole 9 is blocked by the sand discharging element 3, so that impurities such as sand, oil sludge and the like cannot directly fall into the chamber where the mechanical seal 7 is located, the chamber where the mechanical seal 7 is located is filled with the protective medium 16, the protective medium 16 is stable in chemical property, the space occupied by the protective medium 16 is occupied, well fluid 18 is isolated, and the mechanical seal 7 is protected from chemical corrosion.

The embodiment of the invention provides a separation structure, which comprises a protector 8 connected with a driving mechanism, wherein one end of the protector 8 is connected with a connecting joint 1, a sand discharging piece 3 is arranged in the connecting joint 1, the output end of the driving mechanism is connected with a driving shaft 2, the sand discharging piece 3 is sleeved outside the driving shaft 2 and is used for driving the sand discharging piece 3 to rotate around the axial lead of the driving shaft 2 when the driving shaft 2 rotates so as to separate impurities in well fluid entering the connecting joint 1, a sand discharging hole 10 used for discharging the impurities is arranged outside the connecting joint 1, a sand discharging device for an electric pump set is provided based on the separation structure, the impurities in the well fluid entering the connecting joint 1 are separated through the sand discharging piece 3 and then discharged outside the connecting joint 1 through the sand discharging hole 10, and the accumulation of the impurities at the connecting joint 1 and the protector 8 can be reduced through the separation operation of the sand discharging piece 3, effectively guaranteed sealing performance, avoided causing a large amount of leakages, solved current oily charge pump of diving in the work have the impurity in the well fluid easily take place the deposit and influence sealing performance's problem.

The electric appliances presented in the article can be connected with an external main controller and 220V mains supply, and the main controller can be a conventional known device controlled by a computer and the like.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The standard parts used by the invention can be purchased from the market, the special-shaped parts can be customized according to the description and the description of the attached drawings, and the specific connection mode of each part can adopt the conventional means of mature bolts, rivets, welding and the like in the prior art, and the detailed description is not repeated.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.