阅读说明：本技术 膨胀机组合可调型油制动结构 (Adjustable oil braking structure for expander combination ) 是由 王朝 雷磊 刘庆洋 韩杰 邱芳 马小红 王杰 魏凯 于 2020-12-08 设计创作，主要内容包括：本发明公开了膨胀机组合可调型油制动结构,包括由外壳及内壳组成的制动壳体、及装有膨胀轮的膨胀轮轴,膨胀轮轴通过一对轴承活动支承在内壳中；在外壳与内壳之间设有制动油入口油槽及制动油出口排油槽,在外壳上设有连通制动油入口油槽的制动油入口、以及连通制动油出口排油槽的排油口,制动油出口排油槽与内壳相通；在内壳中设有呈环向均匀分布的制动油切向注入油道,每条制动油切向注入油道的方向与该油道同截面内的膨胀轮轴的截面外径相切,每条制动油切向注入油道中油的注入方向与膨胀轮轴的旋转方向相反；在内壳中固定有两组制动片挡板,在每组制动片挡板与制动油注入油道组之间设若干片制动片。本发明具有制动效率高的优点。(The invention discloses an adjustable oil braking structure of an expander combination, which comprises a braking shell consisting of an outer shell and an inner shell, and an expansion wheel shaft provided with an expansion wheel, wherein the expansion wheel shaft is movably supported in the inner shell through a pair of bearings; a brake oil inlet oil groove and a brake oil outlet oil discharge groove are arranged between the outer shell and the inner shell, a brake oil inlet communicated with the brake oil inlet oil groove and an oil discharge port communicated with the brake oil outlet oil discharge groove are arranged on the outer shell, and the brake oil outlet oil discharge groove is communicated with the inner shell; brake oil tangential injection oil ducts which are circumferentially and uniformly distributed are arranged in the inner shell, the direction of each brake oil tangential injection oil duct is tangent to the outer diameter of the section of the expansion wheel shaft in the same section of the oil duct, and the injection direction of each brake oil tangential injection oil duct is opposite to the rotation direction of the expansion wheel shaft; two groups of brake block baffles are fixed in the inner shell, and a plurality of brake blocks are arranged between each group of brake block baffles and the brake oil injection oil duct group. The invention has the advantage of high braking efficiency.)

1. The adjustable oil braking structure of the combination of the expansion unit is characterized in that: the brake comprises a brake shell consisting of an outer shell and an inner shell arranged in the outer shell, and an expansion wheel shaft provided with an expansion wheel, wherein two side shaft ends of the expansion wheel shaft are respectively and movably supported in the brake shell through a bearing arranged in the brake shell; a brake oil inlet oil groove and a brake oil outlet oil discharge groove are arranged between the outer shell and the inner shell, a sealing element for sealing the two oil grooves in a separated mode is arranged between the brake oil inlet oil groove and the brake oil outlet oil discharge groove, a brake oil inlet communicated with the brake oil inlet oil groove and an oil discharge port communicated with the brake oil outlet oil discharge groove are arranged on the outer shell, and the brake oil outlet oil discharge groove is also communicated with an inner cavity of the inner shell; the brake oil injection oil duct group is arranged in the inner shell and comprises a plurality of brake oil tangential injection oil ducts which are circumferentially and uniformly distributed, one end of each brake oil tangential injection oil duct is communicated with an oil groove of the brake oil inlet, the other end of each brake oil tangential injection oil duct penetrates through the inner wall of the inner shell, the direction of each brake oil tangential injection oil duct is tangent to the outer diameter of the section of the expansion wheel shaft in the same section of the oil duct, and the injection direction of the oil in each brake oil tangential injection oil duct is opposite to the rotation direction of the expansion wheel shaft; the brake block comprises an inner shell, wherein two groups of brake block baffles are fixed in the inner cavity of the inner shell, the two groups of brake block baffles are sleeved outside an expansion wheel shaft, the two groups of brake block baffles are symmetrically distributed on two sides of a brake oil injection oil channel group, a flow limiting gap is reserved between each group of brake block baffles and the expansion wheel shaft, a plurality of brake blocks are arranged between each group of brake block baffles and the brake oil injection oil channel group, a brake gap is reserved between each brake block and the expansion wheel shaft, a plurality of brake block axial oil grooves which are circumferentially and uniformly distributed are arranged on the inner wall of each brake block, and a plurality of uniformly distributed oil grooves which are circumferentially and uniformly distributed and correspondingly communicate the brake block axial oil.

2. The adjustable oil brake architecture of expander combinations of claim 1, wherein: the brake oil sealing device is characterized in that two brake oil outlet oil discharge grooves are arranged between the outer shell and the inner shell, the two brake oil outlet oil discharge grooves are located on the left side and the right side of the brake oil inlet oil groove, sealing elements used for sealing the two oil grooves in an isolated mode are respectively arranged between the brake oil inlet oil groove and the adjacent brake oil outlet oil discharge grooves, each brake oil outlet oil discharge groove is communicated with an inner cavity of the inner shell through a first outlet channel arranged on the inner shell, and each brake oil outlet oil discharge groove is communicated with an oil discharge port through a second outlet channel arranged on the outer shell and a third outlet channel arranged on the outer shell.

3. The adjustable oil brake structure of expander combination of claim 2, wherein: the sealing element is a sealing ring which is arranged between the brake oil inlet oil groove and the adjacent brake oil outlet oil discharge groove and is used for sealing a gap between the inner shell and the outer shell.

4. The adjustable oil brake architecture of expander combinations of claim 1, wherein: the brake block and the brake block baffle are detachably arranged on the inner wall of the inner shell through locking screws.

5. The adjustable oil brake architecture of expander combinations of claim 1, wherein: the expansion wheel is detachably fixed on the expansion wheel shaft through a locking bolt.

Technical Field

The invention relates to the technical field of oil brake turbo expanders, in particular to an adjustable oil brake structure of an expander combination.

Background

At present, the braking modes commonly adopted by the turboexpander include oil braking, fan braking and the like. The fan braking mode is generally small in load, but simple in structure, so that the expander with the braking load below 50kw generally adopts the fan braking mode more; the oil braking structure is more complex than the fan braking, the rotating speed of the expansion wheel of the expansion machine is controlled by adjusting the oil pressure and the braking oil quantity, and the oil braking structure has the advantages of stable braking, small noise, large braking range, large-function braking and the like, so that the oil braking structure is more widely applied, particularly applied to the expansion machine with the braking load of more than 50 kw.

The prior oil brake structure is generally provided with a brake at a brake end. The brake mainly comprises an annular brake shell and an oil inlet/outlet channel, wherein the inner wall of the annular brake shell is provided with annular oil grooves which are coaxial with the expansion wheel at the expansion end and have different numbers. The annular oil groove is usually directly processed on the brake shell as a stator as an integral body, the expansion wheel shaft is used as a rotor, brake oil with certain pressure is introduced between the rotor and the stator, work output by the expansion end is converted into heat through friction and taken away by the brake oil, and the brake load and the rotating speed of the expander are changed by adjusting the oil pressure and the oil supply amount. The conventional oil braking technology brakes oil through friction through a gap between a rotor and a stator by only adjusting oil pressure and oil supply amount, the braking mode is single, the braking efficiency is relatively low, a plurality of oil supply channels are needed by a radial annular groove, the oil passage path is long, the structure is large, the oil supply is easy to flow unevenly to cause unstable braking, and the integrated annular fixed oil groove is inconvenient for adjusting the braking load range and is also inconvenient for maintaining and replacing the braking piece.

The existing oil braking technology brakes by oil friction through the clearance between a rotor and a stator only by adjusting oil pressure and oil supply quantity, the braking mode is single, and the braking efficiency is relatively low; and the radial annular groove needs many oil supply channels, the oil duct path is long, the oil supply is easy to flow unevenly to cause unstable local brake oil pressure, and the integrated fixed annular oil groove is inconvenient for adjusting the brake load range.

Disclosure of Invention

The invention aims to provide an expander combined adjustable type oil braking structure capable of improving braking efficiency.

In order to achieve the purpose, the invention adopts the following technical scheme: the adjustable type oil braking structure of expander combination includes: the brake device comprises a brake shell consisting of an outer shell and an inner shell arranged in the outer shell, and an expansion wheel shaft provided with an expansion wheel, wherein two side shaft ends of the expansion wheel shaft are movably supported in the brake shell through a bearing arranged in the brake shell respectively; a brake oil inlet oil groove and a brake oil outlet oil discharge groove are arranged between the outer shell and the inner shell, a sealing element for sealing the two oil grooves in a separated mode is arranged between the brake oil inlet oil groove and the brake oil outlet oil discharge groove, a brake oil inlet communicated with the brake oil inlet oil groove and an oil discharge port communicated with the brake oil outlet oil discharge groove are arranged on the outer shell, and the brake oil outlet oil discharge groove is also communicated with an inner cavity of the inner shell; the brake oil injection oil duct group is arranged in the inner shell and comprises a plurality of brake oil tangential injection oil ducts which are circumferentially and uniformly distributed, one end of each brake oil tangential injection oil duct is communicated with an oil groove of the brake oil inlet, the other end of each brake oil tangential injection oil duct penetrates through the inner wall of the inner shell, the direction of each brake oil tangential injection oil duct is tangent to the outer diameter of the section of the expansion wheel shaft in the same section of the oil duct, and the injection direction of the oil in each brake oil tangential injection oil duct is opposite to the rotation direction of the expansion wheel shaft; the brake block comprises an inner shell, wherein two groups of brake block baffles are fixed in the inner cavity of the inner shell, the two groups of brake block baffles are sleeved outside an expansion wheel shaft, the two groups of brake block baffles are symmetrically distributed on two sides of a brake oil injection oil channel group, a flow limiting gap is reserved between each group of brake block baffles and the expansion wheel shaft, a plurality of brake blocks are arranged between each group of brake block baffles and the brake oil injection oil channel group, a brake gap is reserved between each brake block and the expansion wheel shaft, a plurality of brake block axial oil grooves which are circumferentially and uniformly distributed are arranged on the inner wall of each brake block, and a plurality of uniformly distributed oil grooves which are circumferentially and uniformly distributed and correspondingly communicate the brake block axial oil.

Further, the expander is combined with an adjustable oil braking structure, wherein: the brake oil sealing device is characterized in that two brake oil outlet oil discharge grooves are arranged between the outer shell and the inner shell, the two brake oil outlet oil discharge grooves are located on the left side and the right side of the brake oil inlet oil groove, sealing elements used for sealing the two oil grooves in an isolated mode are respectively arranged between the brake oil inlet oil groove and the adjacent brake oil outlet oil discharge grooves, each brake oil outlet oil discharge groove is communicated with an inner cavity of the inner shell through a first outlet channel arranged on the inner shell, and each brake oil outlet oil discharge groove is communicated with an oil discharge port through a second outlet channel arranged on the outer shell and a third outlet channel arranged on the outer shell.

Further, the expander is combined with an adjustable oil braking structure, wherein: the sealing element is a sealing ring which is arranged between the brake oil inlet oil groove and the adjacent brake oil outlet oil discharge groove and is used for sealing a gap between the inner shell and the outer shell.

Further, the expander is combined with an adjustable oil braking structure, wherein: the brake block and the brake block baffle are detachably arranged on the inner wall of the inner shell through locking screws.

Further, the expander is combined with an adjustable oil braking structure, wherein: the expansion wheel is detachably fixed on the expansion wheel shaft through a locking bolt.

Through the implementation of the technical scheme, the invention has the beneficial effects that:

(1) the main body structure of the oil braking structure provided by the invention is split, the main body structure consists of 1 braking shell, a plurality of braking pieces and 2 braking piece baffles, the braking pieces and the braking piece baffles are stators, the expansion wheel shaft is a rotor, and the gap between the stators and the rotor is a braking oil friction braking gap; the split design differentiates the complexity of single piece manufacturing, reduces the manufacturing difficulty, is convenient for local replacement and maintenance, and reduces the manufacturing cost;

(2) the brake oil in the oil brake structure provided by the invention is tangentially injected into the oil duct and flows in the reverse tangential direction of the rotor rotation direction, after the brake oil with kinetic energy reversely enters the brake clearance, the kinetic energy is converted into the rotation force of the damping rotor, and then the brake oil is braked by friction between the rotor and the stator, so that the brake efficiency is higher under the combined two-stage brake action;

(3) the brake oil in the oil braking structure is uniformly distributed in the circumferential direction and corresponds to the brake pad axial oil grooves uniformly distributed in the circumferential direction on the brake pad, the brake oil can quickly reach the brake pad axial oil grooves uniformly distributed in the circumferential direction through the brake oil tangentially-distributed injection oil passages uniformly distributed in the circumferential direction and the uniformly distributed oil grooves, all the brake pad axial oil grooves are filled with the brake oil, and the oil passages between the brake pad axial oil grooves and the braking gap are uniform and short, so the brake oil in the axial oil grooves can quickly, uniformly and stably fill the braking gap between the stator and the rotor, the braking process is stable, and the braking effect is better;

(4) the brake pad baffle in the oil braking structure is used for preventing the brake oil in the annular oil groove of the brake pad from leaking quickly to cause insufficient brake oil pressure, the current-limiting clearance value between the brake pad baffle and the rotor is the leakage flow area of the brake oil, the leakage flow of the brake oil is adjusted by changing the flow area of the brake pad baffle with different clearance values, and the set oil pressure and oil amount for friction braking between the stator and the rotor are promoted; meanwhile, the brake block is simple to manufacture and convenient to replace, so that the brake block is high in adjustability and easy to replace and maintain;

(5) the oil braking structure provided by the invention is smaller and more compact, is convenient for replacement and maintenance of local parts, and has the advantages of reduced production and manufacturing difficulty, lower investment cost and better braking effect.

Drawings

FIG. 1 is a schematic structural diagram of an adjustable oil braking structure of an expander assembly according to the present invention.

Fig. 2 is a schematic structural view of the section a-a shown in fig. 1.

Fig. 3 is an enlarged schematic view of a portion H shown in fig. 1.

Fig. 4 is a schematic view of the brake pad shown in fig. 1.

Fig. 5 is a schematic view of the brake pad retainer shown in fig. 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

As shown in fig. 1, 2, 3, 4 and 5, the adjustable oil braking structure of the expander combination comprises: the brake comprises a brake shell consisting of an outer shell 1 and an inner shell 2 arranged in the outer shell 1, and an expansion wheel shaft 4 provided with an expansion wheel 3, wherein two side shaft ends of the expansion wheel shaft 4 are respectively and movably supported in the inner shell 2 of the brake shell through a bearing 5 arranged in the inner shell 2 of the brake shell; a brake oil inlet oil groove 6 and a brake oil outlet oil discharge groove 7 are arranged between the outer shell 1 and the inner shell 2, a sealing element 8 for isolating and sealing the two oil grooves is arranged between the brake oil inlet oil groove 6 and the brake oil outlet oil discharge groove 7, and the sealing element 8 seals the brake oil inlet oil groove 6 and the adjacent brake oil outlet oil discharge groove 7 through isolation, so that the brake oil injected from the brake oil inlet 9 is prevented from being discharged from the brake oil inlet oil groove 6 without performing brake work; a brake oil inlet 9 communicated with the brake oil inlet oil groove 6 and an oil discharge port 10 communicated with the brake oil outlet oil discharge groove 7 are formed in the outer shell 1, and the brake oil outlet oil discharge groove 7 is also communicated with the inner cavity of the inner shell 2; a brake oil injection oil duct group is arranged in the inner shell 2, the brake oil injection oil duct group is composed of a plurality of brake oil tangential injection oil ducts 11 which are uniformly distributed in the circumferential direction, one end of each brake oil tangential injection oil duct 11 is communicated with the brake oil inlet oil groove 6, the other end of each brake oil tangential injection oil duct is communicated to the inner wall of the inner shell 2, the direction of each brake oil tangential injection oil duct 11 is tangent to the outer diameter of the section of the expansion wheel shaft 4 in the same section of the brake oil duct, and the injection direction of the oil in each of the brake oil tangential injection oil passages 11 is opposite to the rotation direction of the expansion wheel shaft 4, the oil path design of the brake oil tangential injection oil path 11 can lead the injected brake oil with kinetic energy to reversely enter the brake clearance, then the kinetic energy is converted into the rotating force of the damping rotor, the damping expansion wheel shaft 4 rotates, and then is braked by friction between the damping expansion wheel shaft and the rotor and the stator, and the braking efficiency is higher under the combined double-stage braking action; two groups of brake pad baffles 12 sleeved outside the expansion wheel shaft 4 are fixed in the inner cavity of the inner shell 2, the two groups of brake pad baffles 12 are symmetrically distributed on two sides of the brake oil injection oil duct group, a flow limiting gap is reserved between each group of brake pad baffles 12 and the expansion wheel shaft 4, the flow limiting gap is used for limiting and discharging brake oil, so that the oil pressure and the oil quantity of the injected brake oil meet the set friction braking requirement, and the set rotating speed of the expansion wheel 3 is reached; the brake pad baffle 12 is used for preventing the brake oil in the brake pad axial oil groove 14 from leaking quickly to cause insufficient brake oil pressure, the current limiting gap value between the brake pad baffle 12 and the rotor is the brake oil leakage flow area, the flow area is changed by replacing the brake pad baffles with different gap values, so that the brake oil leakage amount is adjusted, and the set oil pressure and oil amount for friction braking between the stator and the rotor are promoted; a plurality of brake pads 13 are arranged between each group of brake pad baffle plates 12 and the brake oil injection oil channel group, and the brake pads 13 are simple to manufacture and convenient to replace, so that the brake pads are strong in adjustability and easy to replace and maintain; the number of the brake pads 13 can be adjusted in an increasing or decreasing mode according to different brake loads, and the brake area of brake oil can be adjusted by increasing or decreasing the brake pads, so that the brake load capacity can be adjusted; a brake gap is reserved between each brake pad 13 and the expansion wheel shaft 4, and the brake gap is used for introducing brake oil, so that the brake oil applies work to the friction between the rotor and the stator and brakes the rotor; a plurality of brake pad axial oil grooves 14 which are uniformly distributed in the circumferential direction are formed in the inner wall of each brake pad 13, a plurality of uniformly distributed oil grooves 15 which are uniformly distributed in the circumferential direction and correspondingly communicate the brake pad axial oil grooves 14 with the brake oil tangential injection oil passage 11 are formed in the inner wall of the inner shell 2, and the uniformly distributed oil grooves 15 are used for uniformly injecting brake oil; because the brake oil injected into the brake oil inlet oil groove 6 from the brake oil inlet 9 can quickly reach the brake pad axial oil grooves 14 which are uniformly distributed on the brake pad in the circumferential direction through the brake oil tangential injection oil passages 11 which are uniformly distributed in the circumferential direction, the brake oil in the brake pad axial oil grooves 14 can quickly, uniformly and stably fill the brake gaps between the stators and the rotors because the oil passages between the brake pad axial oil grooves 14 and the brake gaps are uniform and short, the braking process is stable, and the braking effect is better.

In this embodiment, two brake oil outlet oil discharge grooves 7 are arranged between the outer shell 1 and the inner shell 2, the two brake oil outlet oil discharge grooves 7 are positioned at the left side and the right side of the brake oil inlet oil groove 6, a sealing member 8 for sealing the two oil grooves in a separated manner is respectively arranged between the brake oil inlet oil groove 6 and the adjacent brake oil outlet oil discharge groove 7, each brake oil outlet oil discharge groove 7 is communicated with an inner cavity 21 of the inner shell 2 through a first outlet channel 16 arranged on the inner shell 2, and each brake oil outlet oil discharge groove 7 is communicated with an oil discharge port 10 through a second outlet channel 17 arranged on the outer shell 1 and a third outlet channel 20 arranged on the outer shell 1, so that oil discharge is more convenient; in the embodiment, the sealing element 8 is a sealing ring which is arranged between the brake oil inlet oil groove 6 and the adjacent brake oil outlet oil discharge groove 7 and is used for sealing a gap between the inner shell 2 and the outer shell 1, so that the manufacturing cost is relatively low, and the use cost of enterprises is reduced; in the embodiment, the brake pad 13 and the brake pad baffle 12 are detachably mounted on the inner wall of the inner shell 2 through the locking screw 18, so that the assembly, disassembly and maintenance are more convenient, and the assembly efficiency is improved; in the embodiment, the expansion wheel 3 is detachably fixed on the expansion wheel shaft 4 through the locking bolt 19, so that the assembly, disassembly and maintenance are more convenient, and the assembly efficiency is improved;

when in work: the outer shell 1, the inner shell 2, the brake disc 13 and the brake disc baffle plate 12 are fixed into a whole to be used as a stator; the expansion wheel 3 and the expansion wheel shaft 4 are mutually fixed into a whole and used as a rotor; under the loading of a gas medium and the common limiting action of the two bearings 5, the rotor rotates clockwise, and in the process, gas expansion does work outwards to obtain low temperature; during braking, brake oil is injected into the brake oil inlet oil groove 6 through the brake oil inlet 9, the brake oil in the brake oil inlet oil groove 6 is injected into each brake oil tangential injection oil duct 11, the brake oil with kinetic energy flowing out of each brake oil tangential injection oil duct 11 enters a brake gap along the rotating direction of the expansion wheel shaft 4, the kinetic energy is converted into the rotating force of the damping rotor, so that the damping expansion wheel shaft 4 rotates, the brake oil flowing out of the brake oil tangential injection oil duct 11 enters the brake pad axial oil grooves 14 which are circumferentially and uniformly distributed on the brake pad through the uniformly distributed oil grooves 15 which are uniformly distributed on the inner wall of the inner shell 2, the brake gap between the stator and the rotor is rapidly, uniformly and stably filled through the brake pad axial oil grooves 14, and through friction braking with the rotor and the stator, under the combined braking action, the braking process is stable and two-stage, and the; during braking, the brake oil in the brake gap flows into the inner cavity 21 of the inner shell 2 through the flow-limiting gap, the brake oil in the inner cavity 21 enters the brake oil outlet oil discharge grooves 7 through the first outlet channels 16, the brake oil in the brake oil outlet oil discharge grooves 7 is collected into the oil discharge port 10 through the second outlet channels 17 and the third outlet channels 20, and the brake oil returns to the brake oil inlet 9 after a series of processes of temperature reduction, filtration, pressure regulation and the like, and is circulated.

The invention has the advantages that:

(1) the main body structure of the oil braking structure provided by the invention is split, the main body structure consists of 1 braking shell, a plurality of braking pieces and 2 braking piece baffles, the braking pieces and the braking piece baffles are stators, the expansion wheel shaft is a rotor, and the gap between the stators and the rotor is a braking oil friction braking gap; the split design differentiates the complexity of single piece manufacturing, reduces the manufacturing difficulty, is convenient for local replacement and maintenance, and reduces the manufacturing cost;

(2) the brake oil in the oil brake structure provided by the invention is tangentially injected into the oil duct and flows in the reverse tangential direction of the rotor rotation direction, after the brake oil with kinetic energy reversely enters the brake clearance, the kinetic energy is converted into the rotation force of the damping rotor, and then the brake oil is braked by friction between the rotor and the stator, so that the brake efficiency is higher under the combined two-stage brake action;

(3) the brake oil in the oil braking structure is uniformly distributed in the circumferential direction and corresponds to the brake pad axial oil grooves uniformly distributed in the circumferential direction on the brake pad, the brake oil can quickly reach the brake pad axial oil grooves uniformly distributed in the circumferential direction through the brake oil tangentially-distributed injection oil passages uniformly distributed in the circumferential direction and the uniformly distributed oil grooves, all the brake pad axial oil grooves are filled with the brake oil, and the oil passages between the brake pad axial oil grooves and the braking gap are uniform and short, so the brake oil in the axial oil grooves can quickly, uniformly and stably fill the braking gap between the stator and the rotor, the braking process is stable, and the braking effect is better;

(4) the brake pad baffle in the oil braking structure is used for preventing the brake oil in the annular oil groove of the brake pad from leaking quickly to cause insufficient brake oil pressure, the current-limiting clearance value between the brake pad baffle and the rotor is the leakage flow area of the brake oil, the leakage flow of the brake oil is adjusted by changing the flow area of the brake pad baffle with different clearance values, and the set oil pressure and oil amount for friction braking between the stator and the rotor are promoted; meanwhile, the brake block is simple to manufacture and convenient to replace, so that the brake block is high in adjustability and easy to replace and maintain;

(5) the oil braking structure provided by the invention is smaller and more compact, is convenient for replacement and maintenance of local parts, and has the advantages of reduced production and manufacturing difficulty, lower investment cost and better braking effect.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, but any modifications or equivalent variations made in accordance with the technical spirit of the present invention are within the scope of the present invention as claimed.