阅读说明：本技术 一种自动控温燃气安全阀 (Automatic temperature control gas safety valve ) 是由 李俊德 张见宗 于 2020-09-28 设计创作，主要内容包括：本发明涉及燃气阀门相关技术领域,且公开了一种自动控温燃气安全阀,包括阀体,所述阀体的内壁一侧开设有进气室。本发明通过在活动阀芯内壁设有电磁块,同时,在电磁块的两端设有活动推块,且两个活动推块分别与阀体内壁的活动接触,因而在需要调节燃气量时,通过电磁圈通电促使活动推块向两侧运动,进而使得燃气从透气槽处流出,实现控制燃气的通闭,同时,由于活动阀芯通过上锥形安装至阀体上,因而当电磁块无磁性时,其活动阀芯受重力及燃气对活动阀芯的推力促使活动推块将透气槽封闭,进而增加密封的效果,并通过自密封取代了弹簧弹性密封,避免了因弹簧失效而导致密封失效的现象,最终达到长期高效密封的目的。(The invention relates to the technical field related to gas valves and discloses an automatic temperature control gas safety valve which comprises a valve body, wherein an air inlet chamber is formed in one side of the inner wall of the valve body. The electromagnetic block is arranged on the inner wall of the movable valve core, the movable push blocks are arranged at two ends of the electromagnetic block and are respectively in movable contact with the inner wall of the valve body, so that when the gas quantity needs to be adjusted, the movable push blocks are driven to move towards two sides by electrifying the electromagnetic coil, the gas flows out from the ventilating groove, the gas is controlled to be communicated and closed, meanwhile, the movable valve core is installed on the valve body through the upper cone, when the electromagnetic block is non-magnetic, the movable valve core is driven to seal the ventilating groove by the movable push blocks under the action of gravity and the thrust of the gas on the movable valve core, the sealing effect is improved, the elastic sealing of the spring is replaced by self-sealing, the phenomenon that the sealing fails due to the failure of the spring is avoided, and the purpose of long-term and efficient sealing is finally achieved.)

1. An automatic temperature control gas safety valve comprises a valve body (1), wherein an air inlet chamber (2) is formed in one side of the inner wall of the valve body (1), an electromagnetic safety valve (3) located in the air inlet chamber (2) is fixedly installed on the inner wall of the valve body (1), an air conveying passage (4) communicated with the air inlet chamber (2) is horizontally formed in the inner wall of the valve body (1), an adjusting valve core (5) matched with the air conveying passage (4) is movably installed on the inner wall of the valve body (1), an adjusting rod (6) is movably installed at the top end of the adjusting valve core (5), a sealing valve core (7) located below the adjusting valve core (5) is movably installed on the inner wall of the valve body (1), a temperature control component (8) is fixedly installed on one side of the bottom of the valve body (1), an air outlet passage (9) communicated with a cavity below the sealing valve core (7), the method is characterized in that: the adjustable electromagnetic valve is characterized in that a conical bearing seat table is arranged on one side of the inner wall of the valve body (1) and below the adjusting valve core (5), the diameter value of the upper end of the bearing seat table is larger than that of the lower end of the bearing seat table, a movable valve core (10) is movably mounted on the inner wall of the bearing seat table on the inner wall of the valve body (1), an upper ventilation groove (11) and a lower ventilation groove (11) are formed in the surface of the movable valve core (10), movable push blocks (12) used for sealing the ventilation grooves (11) are movably mounted on the two sides of the inner wall of the movable valve core (10), one ends of the movable push blocks (12) are oblique angles, the oblique angles are matched with the oblique angles of the side walls of the movable valve core (10), electromagnetic blocks (13) are fixedly mounted in the middle of the inner wall of the movable valve core (10), electromagnetic rings (14) are arranged on the side walls of the electromagnetic blocks (13), the movable push blocks (12) are located on the two sides of the end faces of the 16) The middle part of the bottom surface of the movable valve core (10) is fixedly provided with a lead (17), and the electromagnetic coil (14) is communicated with the temperature control component (8) through the lead (17).

2. The automatic temperature control gas safety valve according to claim 1, characterized in that: the two ends of the electromagnetic block (13) are respectively and fixedly provided with a cylindrical magnetic conduction block (15), and the side wall of the magnetic conduction block (15) is fixedly installed with the inner wall of the movable valve core (10) in a sealing manner.

3. The automatic temperature control gas safety valve according to claim 1, characterized in that: a sealing ring (18) is movably mounted at the top of the side wall of the movable valve core (10), and the end face of the sealing ring (18) is cylindrical.

4. The automatic temperature control gas safety valve according to claim 1, characterized in that: the inner wall of the valve body (1) is fixedly provided with a guide sliding block (19) at the installation position of the movable valve core (10), and the surface of the guide sliding block (19) is a smooth surface.

5. The automatic temperature control gas safety valve according to claim 1, characterized in that: the opening area of the end surface of the ventilation groove (11) is 1.3-1.5 times of the end area of the air transmission channel (4).

6. The automatic temperature control gas safety valve according to claim 1, characterized in that: the upper side and the lower side of the movable push block (12) are both fixedly provided with rubber blocks for sealing.

7. The automatic temperature control gas safety valve according to claim 4, characterized in that: the movable valve core (10) is in a round table shape, and the inclination angle of the side wall of the movable valve core (10) is matched with the inclination angle of the inner wall of a guide sliding block (19) arranged on the inner wall of the valve body (1).

Technical Field

The invention relates to the technical field related to gas valves, in particular to an automatic temperature control gas safety valve.

Background

In order to cut off the gas quantity of the gas-fired heating device, the gas-fired oven and other devices which use gas for heating in time, the purpose of automatic gas cut-off is achieved when the required temperature reaches a certain temperature through an automatic temperature control gas safety valve.

The working principle of the existing gas warmer is mainly as follows: the valve body is arranged in the conveying pipeline, the gas inlet chamber and the gas inlet of the gas pipeline are fixedly arranged, the gas outlet channel is connected with the gas outlet of the gas channel, the gas in the gas inlet chamber is opened by the electromagnetic safety valve, the gas is conveyed to the position of the regulating valve core through the gas conveying channel, the flow speed of the gas from the position of the regulating valve core is controlled by the regulating rod, meanwhile, the working temperature is detected by the temperature control component, the distance between the gas and the valve core is weakened and sealed through the regulating spring when the temperature is normal, the gas at the position of the regulating valve core can flow to the gas outlet channel through the sealed valve core, if the temperature control component detects that the working temperature is overhigh, the sealed valve core is pressed through the spring, so that the small-flow gas flow is realized through the elasticity between the springs, and meanwhile, when the temperature is continuously increased, the sealed valve core is pressed through the continuous rising of the spring, thereby realizing the purpose of gas cutoff.

However, in the actual use process of the automatic temperature control gas valve, the valve core is sealed to be isolated from the gas in the regulating valve core mainly through spring jacking, and meanwhile, the valve core is sealed to be capable of enabling the gas flow in the regulating valve core to partially enter the gas outlet channel, so that the control of the gas inflow is realized through the elasticity of the spring, the phenomenon that the gas isolation cannot be performed easily when the spring is in a continuous alternating stress state is promoted, and the phenomenon that the gas isolation cannot be performed is avoided after the spring is damaged, so that great potential safety hazards are not found.

And because current shut off the case through from installing to the valve body down, therefore at the in-process that carries out low discharge gas and carry, the gas in its regulation case only needs to overcome the spring force of shutting off case below and can circulate the gas, nevertheless because the elasticity direction of spring is upwards all the time, thereby when having leaded to the gas pressure in the regulation case to weaken, can directly shut off the case through the spring and shut off, thereby can't realize adjusting the gas output according to the gas pressure intensity in the regulation case, thereby unable adaptation is because of the gas pressure low phenomenon of normal use.

Disclosure of Invention

Aiming at the defects of the existing automatic temperature control gas valve in the use process in the background art, the invention provides an automatic temperature control gas safety valve which has the advantages of long-term efficient sealing, stable gas outlet and stepless regulation and control, and solves the technical problems in the background art.

The invention provides the following technical scheme: an automatic temperature control gas safety valve comprises a valve body, wherein an air inlet chamber is formed in one side of the inner wall of the valve body, an electromagnetic safety valve positioned in the air inlet chamber is fixedly installed on the inner wall of the valve body, an air transmission channel communicated with the air inlet chamber is horizontally formed in the inner wall of the valve body, an adjusting valve core matched with the air transmission channel is movably installed on the inner wall of the valve body, an adjusting rod is movably installed at the top end of the adjusting valve core, a sealed valve core positioned below the adjusting valve core is movably installed on the inner wall of the valve body, a temperature control part is fixedly installed on one side of the bottom of the valve body, an air outlet channel communicated with a cavity below the sealed valve core is arranged on the inner wall of the valve body, a conical bearing table is arranged on one side of the inner wall of the valve body and positioned below the adjusting valve core, the diameter value of the upper end, the surface of the movable valve core is provided with an upper ventilation groove and a lower ventilation groove which are communicated with each other, two sides of the inner wall of the movable valve core are respectively and movably provided with a movable push block for sealing the ventilation grooves, one end of the movable push block is in an oblique angle, the oblique angle of the movable push block is matched with the oblique angle of the side wall of the movable valve core, the middle of the inner wall of the movable valve core is fixedly provided with an electromagnetic block, the side wall of the electromagnetic block is provided with an electromagnetic coil, the movable push block is positioned on two sides of the end face of the electromagnetic block, the top end of the electromagnetic block is respectively and fixedly provided with a permanent magnet which is repelled with the magnetic pole on the end face of the electromagnetic block, the middle of the bottom.

Preferably, the two ends of the electromagnetic block are respectively and fixedly provided with a cylindrical magnetic conduction block, and the side wall of the magnetic conduction block and the inner wall of the movable valve element are fixedly installed in a sealing manner.

Preferably, a sealing ring is movably mounted at the top of the side wall of the movable valve core, and the end surface of the sealing ring is cylindrical.

Preferably, the inner wall of the valve body is fixedly provided with a guide sliding block at the installation position of the movable valve core, and the surface of the guide sliding block is a smooth surface.

Preferably, the opening area of the end face of the ventilation groove is 1.3-1.5 times of the area of the end of the gas transmission channel.

Preferably, the upper side and the lower side of the movable push block are both fixedly provided with rubber blocks for sealing.

Preferably, the movable valve core is in a circular truncated cone shape, and the inclination angle of the side wall of the movable valve core is matched with the inclination angle of the inner wall of the guide sliding block arranged on the inner wall of the valve body.

The invention has the following beneficial effects:

1. the electromagnetic block is arranged on the inner wall of the movable valve core, the movable push blocks are arranged at two ends of the electromagnetic block and are respectively in movable contact with the inner wall of the valve body, so that when the gas quantity needs to be adjusted, the movable push blocks are driven to move towards two sides by electrifying the electromagnetic coil, the gas flows out from the ventilating groove, the gas is controlled to be communicated and closed, meanwhile, the movable valve core is installed on the valve body through the upper cone, when the electromagnetic block is non-magnetic, the movable valve core is driven to seal the ventilating groove by the movable push blocks under the action of gravity and the thrust of the gas on the movable valve core, the sealing effect is improved, the elastic sealing of the spring is replaced by self-sealing, the phenomenon that the sealing fails due to the failure of the spring is avoided, and the purpose of long-term and efficient sealing is finally achieved.

2. The invention opens and closes the ventilation groove by the movable push block through repulsion between the electromagnetic block and the permanent magnet, so that in the working process of the fuel gas, the magnetic repulsion force between the electromagnetic block and the permanent magnet is influenced by the self weight of the movable valve core and the fuel gas pressure impact, when the fuel gas is reduced, in order to ensure the normal supply of the fuel gas quantity, the pressure of the electromagnetic block impacted by the fuel gas is reduced, and further the magnetic repulsion force between the electromagnetic block and the permanent magnet promotes the movable push block to move, so that the opening of the ventilation groove is increased, the flow area of the fuel gas in the ventilation groove is increased, and similarly, when the pressure of the fuel gas is higher, the opening of the ventilation groove is reduced by the movable push block, so that the stable gas output is ensured, and the purpose of stably outputting the fuel gas is finally achieved.

3. The electromagnetic coil provides a condition for generating magnetic force for the electromagnetic block, and meanwhile, the electromagnetic coil is connected with the temperature control part through the lead, the temperature control part is a temperature control detection thermistor, so that when the temperature control part is heated, the resistance value is increased, the current on the electromagnetic coil is reduced, the magnetic force on the electromagnetic coil is linearly changed within a certain range, the opening size of the ventilation groove can be steplessly adjusted by the movable push block according to the actual use temperature through the linear change of the current on the electromagnetic coil, the gas can be weakened according to the actual requirement, and the purpose of stepless regulation and control is finally achieved.

Drawings

FIG. 1 is a prior art schematic of the structure of the present invention;

FIG. 2 is a schematic sectional view of the present invention with a modified structure;

fig. 3 is a schematic view of the movable valve core of the structure of the invention.

In the figure: 1. a valve body; 2. an air intake chamber; 3. an electromagnetic safety valve; 4. a gas delivery passage; 5. adjusting the valve core; 6. adjusting a rod; 7. sealing the valve core; 8. a temperature control member; 9. an air outlet channel; 10. a movable valve core; 11. a ventilation groove; 12. a movable push block; 13. an electromagnetic block; 14. an electromagnetic coil; 15. a magnetic conduction block; 16. a permanent magnet; 17. a wire; 18. a seal ring; 19. and a guide slide block.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-3, an automatic temperature control gas safety valve comprises a valve body 1, an air inlet chamber 2 is arranged on one side of the inner wall of the valve body 1, an electromagnetic safety valve 3 positioned in the air inlet chamber 2 is fixedly installed on the inner wall of the valve body 1, an air delivery passage 4 communicated with the air inlet chamber 2 is horizontally arranged on the inner wall of the valve body 1, an adjusting valve core 5 matched with the air delivery passage 4 is movably installed on the inner wall of the valve body 1, an adjusting rod 6 is movably installed at the top end of the adjusting valve core 5, a sealing valve core 7 positioned below the adjusting valve core 5 is movably installed on the inner wall of the valve body 1, a temperature control part 8 is fixedly installed on one side of the bottom of the valve body 1, an air outlet passage 9 communicated with a chamber below the sealing valve core 7 is arranged on the inner wall of the valve body 1, a conical bearing table is arranged below the adjusting valve core 5 on one, a movable valve core 10 is movably mounted on the inner wall of a bearing platform on the inner wall of the valve body 1, a ventilation groove 11 which is communicated with the upper part and the lower part is arranged on the surface of the movable valve core 10, movable push blocks 12 which are used for sealing the ventilation groove 11 are movably mounted on two sides of the inner wall of the movable valve core 10 respectively, one end of each movable push block 12 is an oblique angle, the oblique angle is matched with the oblique angle of the side wall of the movable valve core 10, an electromagnetic block 13 is fixedly mounted in the middle of the inner wall of the movable valve core 10, an electromagnetic ring 14 is arranged on the side wall of the electromagnetic block 13, the movable push blocks 12 are positioned on two sides of the end face of the electromagnetic block 13, permanent magnets 16 which repel magnetic poles on the end face of the electromagnetic block 13 are fixedly mounted on the top end face of the electromagnetic block 13 respectively, a lead 17 is fixedly mounted in the middle of the bottom face of the movable valve core 10, the electromagnetic ring 14 is, and contact with the bearing platform of the inner wall of the valve body 1 through the movable push block 12, therefore in the course of using, can jack up the movable valve core 10 through the repulsion that the both ends of electromagnetic block 13 produce, meanwhile, its fuel gas flows out through opening on the ventilative trough 11, later, when needing to cut off the fuel gas, through the fuel gas above the movable valve core 10 to the pressure of the movable valve core 10 impel the movable push block 12 to the inboard movement of the movable valve core 10, and then seal the ventilative trough 11, meanwhile, through the movable valve core 10 and taking advantage of the conical phase adaptation of the seat platform on the valve body 1, and then make the pressure above the movable valve core 10 greater, the sealed effect of its movable valve core 10 is the greater, has avoided therefore the spring failure and has led to the phenomenon that the sealed effect becomes worse.

Meanwhile, because the opening of the movable push block 12 is performed through the magnetic repulsion of the electromagnetic block 13, in order to achieve the purpose of stably discharging gas, one side of the movable push block 12 is contacted with a bearing platform on the inner wall of the valve body 1, further, the gas pressure above the movable valve core 10 is balanced with the magnetic repulsion between the electromagnetic block 13 and the permanent magnet 16, and when the gas pressure above the movable valve core 10 is reduced, the pressure value of the gas above the movable valve core 10 and the movable valve core 10 is reduced, meanwhile, the extrusion force of the movable valve core 10 to the movable push block 12 is relatively reduced, because the magnetic repulsion of the electromagnetic block 13 to the permanent magnet 16 is unchanged, when the gas pressure above the movable valve core 10 is weakened, the outward movement distance of the movable push block 12 is increased through the magnetic repulsion of the electromagnetic block 13, further, the opening size of the ventilation groove 11 is increased, and the purpose of increasing the gas quantity in unit time is achieved, in a similar way, when the gas pressure above the movable valve element 10 is increased, the opening of the ventilation groove 11 is relatively reduced by the movable push block 12, and then the aim of balancing the gas quantity is achieved by increasing the gas quantity and flow speed in the unit area.

And, because the magnetic force on the electromagnetic block 13 is changed by the current that the electromagnetic coil 14 provided through the temperature control part 8, its temperature control part 8 is for the thermistor, its resistance increases when the temperature increases, therefore after the temperature control part 8 detects the temperature rise to a certain degree, can reduce the electric current on the electromagnetic coil 14 through the increase of resistance, and then realize the purpose that the magnetic force of electromagnetic block 13 weakens, simultaneously, because the electric current is the linear enhancement and weakens, therefore in the process that the ventilative groove 11 size of opening and shutting of the promotion activity ejector pad 12 of electromagnetic block 13, because the change of self magnetic force value, and then make the gas flow on the ventilative groove 11 also can corresponding enhancement and weakening, thereby realize the purpose of stepless regulation and control gas flow.

Wherein, the both ends of electromagnetism piece 13 are cylindrical magnetic conduction piece 15 of fixed mounting respectively, and the sealed fixed mounting of the lateral wall of magnetic conduction piece 15 and the inner wall of activity valve core 10, for the transport that the electric current spark that prevents to produce influences the gas in the electromagnetic ring 14, therefore have magnetic conduction piece 15 through the both ends fixed mounting at electromagnetism piece 13, and can transmit magnetism away through magnetic conduction piece 15, in order to guarantee that permanent magnet 16 drives the normal release of activity ejector pad 12, and simultaneously, still prevented the gas flow of activity valve core 10 top to the electromagnetic ring 14 in, avoided leading to gas explosion's phenomenon because of electromagnetic ring 14 produces the spark.

Wherein, the lateral wall top movable mounting of activity case 10 has sealing ring 18, and the terminal surface shape of sealing ring 18 is cylindrically, in order to prevent that activity case 10 is at the in-process of jack-up, its gas flows from the lateral wall of activity case 10, and then establish sealing ring 18 into the circular rubber that can compress by a wide margin and stretch out, therefore in-process when activity case 10 rises, the extension through sealing ring 18 has prevented the phenomenon that the gas flows from activity case 10 lateral wall, and then guaranteed ventilative groove 11 department control gas flow more accurate.

Wherein, the inner wall of the valve body 1 is located and fixedly mounted with the installation position of the movable valve element 10 and is provided with a guide slide block 19, and the surface of the guide slide block 19 is a smooth surface, in order to make the movable push block 12 jack up the movable valve element 10 more easily in the extending process, the guide slide block 19 is installed at the contact position of the movable push block 12 and the bearing table on the valve body 1, and the sliding friction force of the movable push block 12 on the guide slide block 19 can be reduced through the guide slide block 19, so that the movable valve element 10 is more easily lifted.

Wherein, the terminal surface open area of ventilative groove 11 is 1.3-1.5 times of gas transmission 4 terminal surface area, reduces the gas transmission volume when the gas volume that prevents ventilative groove 11 to pass through from ventilative groove 11 transmission, therefore through being greater than the terminal surface diameter of gas transmission way 4 with the terminal surface open diameter of ventilative groove 11, therefore when the gas in gas transmission way 4 is whole to flow, all can follow ventilative groove 11 and carry out the gas, avoided influencing the phenomenon of gas transmission volume because of ventilative groove 11 opening is less.

Wherein, the equal fixed mounting in upper and lower both sides of activity ejector pad 12 has the rubber piece that is used for sealing, in order to strengthen sealed effect, therefore installs the sealing rubber piece respectively through the upper and lower both sides at activity ejector pad 12 to when activity ejector pad 12 will breathe freely groove 11 and seal, through the close contact of sealing rubber piece with ventilative groove 11, prevented to take place the phenomenon of gas leakage because of activity ejector pad 12 lasts to slide.

Wherein, the shape of activity case 10 is the round platform shape, and the lateral wall inclination of activity case 10 and the 19 inner wall inclination looks adaptations of the guide slide of 1 inner wall installation of valve body, in order to prevent that activity case 10 can't carry out the return again after receiving the rotation, therefore establish activity case 10 to the round platform shape, and simultaneously, accomplish self-align with the gas pressure of activity case 10 top through the dead weight of activity case 10, and, because the lateral wall of activity case 10 is equal all, therefore still can realize self-align after activity case 10 is rotatory, finally realize the purpose of border location.

The using method of the invention has the following working principle: firstly, fixing the valve body 1 to a proper position, secondly, communicating the air inlet chamber 2 with a fuel gas inlet pipe, simultaneously communicating the air outlet channel 9 with a fuel gas outlet pipe, and placing the temperature control component 8 to a proper position;

the working state is as follows: the electromagnetic safety valve 3 is electrified and opened, so that the gas in the gas inlet chamber 2 flows into the gas transmission channel 4, the gas in the gas transmission channel 4 flows to the upper part of the movable valve core 10 from the adjusting valve core 5, meanwhile, the aperture area of the gas transmission channel 4 when the gas is transmitted from the adjusting valve core 5 can be controlled by rotating the adjusting rod 6, secondly, the temperature detection on the temperature control part 8 accords with the normal use temperature, further, the current on the electromagnetic coil 14 is increased, the magnetism at two ends of the electromagnetic block 13 is increased, the magnetism is transmitted out through the magnetic conduction blocks 15 at two ends of the electromagnetic block 13, secondly, the permanent magnets 16 at two ends of the electromagnetic block 13 are influenced by the magnetic force of the magnetic conduction blocks 15, further, the permanent magnets 16 are enabled to jack up the movable push block 12 towards two ends, afterwards, one side of the movable push block 12 is contacted with the inner wall of the valve body 1 and jacks up the movable valve core 10, and the opening of the air permeation groove 11 is increased due to the, meanwhile, the fuel gas above the movable valve core 10 flows to the gas outlet channel 9 from the ventilating groove 11, so that the normal use of the fuel gas is completed;

when the temperature is too high: when the temperature sensed by the temperature control part 8 is too high, the current on the electromagnetic coil 14 can be reduced, and the magnetism at two ends of the electromagnetic block 13 is further reduced, and because the pressure value of the gas above the movable valve core 10 is stable, the movable valve core 10 is pressed by the gas, the movable valve core 10 is promoted to extrude the movable push blocks 12 at two sides, so that the movable push blocks 12 contract inwards, the opening size of the ventilation groove 11 is reduced, and the flow quantity of the gas from the ventilation groove 11 is further reduced;

when the gas pressure is unstable: when gas pressure increases, because the magnetic force of electromagnetism piece 13 both sides is unchangeable, and then make the gas promote activity ejector pad 12 to extrude inwards through acting on activity case 10, and then reduce the opening size of ventilative groove 11, and simultaneously, because the gas pressure increase of activity case 10 top, the opening on its ventilative groove 11 reduces, and then make the gas volume of following ventilative groove 11 department flow in the unit interval tend to the balance, and then guarantee gas volume exhaust stability, the same reason, when the gas volume of activity case 10 top weakens, it promotes the motion of activity ejector pad 12 to both sides to receive the magnetic force influence, and then increase the opening size of ventilative groove 11.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.