CN201253948Y

CN201253948Y - Film blowing machine rotary die head suitable for starch biological degradation material

Info

Publication number: CN201253948Y
Application number: CNU2008200681328U
Authority: CN
Inventors: 方墉; 吴平
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-06-27
Filing date: 2008-06-27
Publication date: 2009-06-10
Anticipated expiration: 2018-06-27

Abstract

The utility model relates to a rotary die of film blowing machine which is suitable for starch biodegradable materials. The rotary die comprises a core die part and an outer body, the core die part comprises a spiral core die arranged on the center shaft and a rotary core die arranged fixedly on the upper end of the center shaft, the spiral core die is clung to the rotary core die, the center shaft is driven by a motor to drive the rotary core die to rotate relative to the spiral core die, the outer body comprises an inner die sleeve arranged on the spiral core die, an outer die sleeve transitionally matched with the inner die sleeve, and an opening die sleeve arranged outside the rotary core die, the inner die sleeve and the opening die sleeve are connected by a fixing part, an outer circulation cooling water channel is arranged between the inner die sleeve and the outer die sleeve. The inner die sleeve, the opening die sleeve, the spiral core die and the rotary core die are combined to form a flowing and molding channel, the flowing and molding channel is composed of a reversed V-shaped feed slot, a spiral conveying slot, an annular gap buffer belt, a tapered channel, an annular loose material cavity and a final molding segmental gap. The blown film made by starch material has high qualification ratio and can be produced in mass.

Description

Be suitable for the inflation film manufacturing machine rotating die head of starch biological degradation material

Technical field

The utility model relates to sheet blowing equipment, refers to a kind of inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material particularly.

Background technology

The principle of inflation film moulding is that plastic raw materials is pressed into the die head from the screw extruder front end, make the plastic raw materials of viscous state be extruded into pipe embryo shape through die head, and the compressed air that utilizes die head bottom to feed will be managed embryo and evenly freely will be blown into the bigger tubular film of diameter, make simultaneously tubular film in the process of upwards traction by longitudinal stretching, progressively cooling, flattened by collapser, the carry-over pinch rolls traction is wound into tube at last again.Along with the inflation film technology reaches its maturity and perfect, the plastic sheeting of various blowfilm shapings has been applied to fields such as industry, agricultural and daily life more and more.Plastic sheeting is a macromolecule material product, various plastic membrane products are when being convenient for people to use, enhancing productivity and reducing labor strength, a large amount of discarded films also can form the white pollution that is difficult to degrade, and how to deal carefully with a great problem that discarded film has just become people to face.

In order to address the above problem, the scientific research personnel is attempting the natural biological degradable material substituted chemistry plastics with high-content of starch always, successfully developed at present multiple can partially or completely biodegradable starch film, as the fully-biodegradable film of Granted publication number for being introduced in the Chinese invention patent specification of CN1293137C.The Biodegradable film of high-content of starch can be melted by the moisture content in the environment soon, in soil, also can be decomposed fast by microorganism, even change into fertilizer, this has alleviated the pollution problem of the discarded film of conventional plastic to a great extent, more and more emphasize today of environmental protection people, its market prospects are also more and more wide.But the inherent characteristic of starch biological degradation material has also been brought a new difficult problem that is difficult to mass industrialized production.

Trace it to its cause, comprise following several respects factor: the one, starch biological degradation material is compared with common high density polyethylene (HDPE) or low density polyethylene (LDPE), its viscosity is higher, mobile variation, not only cause material in the process of mixing plasticizing, non-uniform phenomenon to occur easily, and the pressure in the die head is sharply raise, conventional plastic blown film die head is difficult to make its precise forming.The 2nd, the shear stress of starch biological degradation material is bigger, and frictional heat increases suddenly in the process of mixing plasticizing, and conventional plastic blown film die head is difficult to accurately control its technological temperature.The 3rd, starch biological degradation material is higher to the sensitiveness of technological temperature, and the intensification certainly in process is too high, cause the sex change of the burnt paste of material easily, need carry out more harsh control to the technological temperature of material, and conventional plastic blown film die head obviously can't be accomplished this point.

This shows that though the blown film principle and the common plastics of starch biological degradation material are basic identical, key wherein is that existing inflation film manufacturing machine die head can't solve this new material because of big, mobile poor, the responsive problem of bringing of technological temperature of viscosity.As using existing plastic membrane blowing production line to produce the starch biodegradation film by force, not only yield poorly down, and yields is very low, can't satisfy the needs of industrialized mass.

Summary of the invention

The purpose of this utility model will overcome the existing deficiency of traditional blow moulding machine blowing biodegradation new material exactly, provide a kind of product qualified rate height, can mass industrialized production the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material.

For achieving the above object, the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material that the utility model is designed, mainly arrange that by concentric core part and outer body portion in order to constitute material annular space circulation road combine:

Described plug portion branch comprises by spring bearing and is sleeved on the spiral core on the central shaft and is fixed on the rotation core of central shaft upper end by locking nut, the lower end outer conical surface close fit of the upper end internal conical surface of described spiral core and rotation core;

Described outer body portion comprise the interior die sleeve that is sleeved on the spiral core, with the outer die casing of interior die sleeve interference fits and the mouth die sleeve that is arranged in the rotation core outside, the upper surface of die sleeve is connected as a single entity by fixture with the lower surface of mouthful die sleeve in described, is provided with the outer circulation cooling water channel between the outer wall of described interior die sleeve and the inwall of outer die casing;

Logistics of common formation and shaping channel between the outer wall of the inwall of described interior die sleeve and mouthful die sleeve and spiral core and rotation core, described logistics and shaping channel are made up of herringbone feed well, spirality feeding groove, annular gap buffer strip, tapering type conical surface passage, annular lax material chamber and last profiled section gap from bottom to top successively;

Described core part and outer body portion integral body are seated on the die head base, described die head base is fixed on the connecting plate, the lower end of described central shaft is passed connecting plate and is linked to each other with gear wheel, also be fixed with motor on the described connecting plate, the output of described motor links to each other with pinion, described pinion and gear wheel engagement fit, thus the rotation core that drives central shaft and upper end thereof rotates with respect to the spiral core.

Further, the axle center of described central shaft is dark blind hole shape structure, is provided with interior circulating cooling water pipe in it, and its end is provided with the swivel joint that matches with interior circulating cooling water pipe, can partly implement the water-cooled temperature control of effect to described core.

Further, offer spiral recirculated cooling water road in the barrel of described mouthful of die sleeve, can act synergistically, strengthen water-cooled temperature control effect described outer body portion with above-mentioned outer circulation cooling water channel.

Compare with traditional blow moulding machine die head, advantage of the present utility model is mainly reflected in the following aspects:

One, designed logistics and shaping channel smoothly are combined into one continuously by herringbone feed well, spirality feeding groove, annular gap buffer strip, tapering type conical surface passage, annular lax material chamber and these six parts of last profiled section gap, both had function separately, have collaborative effect again: the herringbone feed well can the efficient allocation logistics, guarantees that under the prerequisite that satisfies flow and flow velocity material evenly carries; The spirality feeding groove can change the structural stress in the material, and material temperature is tending towards evenly, makes material further plasticizing in flow process simultaneously; The annular gap buffer strip can temporarily discharge the pressure in the plastifying material, makes it reach free state uniformly; Tapering type conical surface passage can increase material flow, and makes material rebulid pressure; The lax material of annular chamber can discharge the pressure in the plastifying material once more, eliminates the mobile variation of material as far as possible, makes its state further free balanced; Last profiled section gap can make material set up blown film pressure once more, and through the process of twice pressure release and foundation, material has even temperature, pressure and flow velocity more, for final blown film has been created advantage.

Its two, the herringbone feed well of designed logistics and shaping channel, spirality feeding groove, annular gap buffer strip and tapering type conical surface passage are static constant, material can stably be carried therein, mixes, plastify; Annular lax material chamber and last profiled section gap then are dynamically rotations, rotation core slow speed with 2RPM under the drive of motor and speed reduction gearing is rotated, material is rotated the driving of core therein and is done simultaneously axially and tangential motion, can effectively overcome the inhomogeneities that big, the mobile difference of starch biological degradation material viscosity is caused, further eliminate internal stress and velocity deviation, make the distribution of material more even, lay a good foundation for improving final quality of forming film.

They are three years old, designed outer circulation cooling water channel along the circumferential direction is enclosed in the outside of logistics and shaping channel, the heat that die sleeve and outer die casing place produce in can absorbing by flow velocity, the flow of regulating cooling water, thereby the frictional heat that the control material produces in mixing plasticizing process, regulate the variations in temperature of material in each section passage easily, it is remained in the needed scope of blown film; Designed interior circulating cooling water pipe in the central shaft blind hole partly implements the water-cooled cooling of effect to core from the inboard of logistics and shaping channel, with outer circulation cooling water channel synergy, can further improve the accuracy of temperature of charge control; Designed spiral recirculated cooling water road in mouth die sleeve barrel can be regulated and control the temperature of charge of last profiled section gap location more accurately, guarantees material blowfilm shaping under the temperature conditions that is fit to self-characteristic, and large-scale mass production stably.

In sum, inflation film manufacturing machine rotating die head of the present utility model designs with logistics that dynamically combines and shaping channel by static, add unique internal and external circulating water cooling system, make the mixing, decompression, pressurization of blown film material and the own characteristic that temperature control can meet material fully, efficiently solve starch biological degradation material viscosity big, mobile poor, to the difficult problem of technological temperature sensitivity.Its blown film speed is fast, constant product quality, yield rate and yields height, and whole process of production can realize control automatically or artificial control, can reach the requirement of mass industrialized production fully.Simultaneously, inflation film manufacturing machine rotating die head of the present utility model can be retrofitted on traditional blown film unit easily, under the situation of original production line not being done to adjust significantly, produce the starch biodegradation film, it is with low cost, can replace plastic sheeting, stop white pollution, have good economic benefit and social benefit.

Description of drawings

Fig. 1 is the main sectional structure schematic diagram of inflation film manufacturing machine rotating die head of the present utility model;

Fig. 2 is the left sectional structure schematic diagram of Fig. 1;

Fig. 3 is the plan structure schematic diagram of Fig. 1;

Fig. 4 is the deployed condition schematic diagram of the outer circulation cooling water channel among Fig. 1;

Fig. 5 is the deployed condition schematic diagram of the herringbone feed well among Fig. 1.

The specific embodiment

Below in conjunction with the drawings and specific embodiments inflation film manufacturing machine rotating die head of the present utility model is described in further detail:

The inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material shown in the figure mainly is made of core part and the outer body portion that concentric is arranged, this is two-part specifically to be constructed as follows:

Above-mentioned core partly is the key component of whole die head, and it comprises by spring bearing 28 and is sleeved on the spiral core 22 on the central shaft 15 and is fixed on the rotation core 20 of central shaft 15 upper ends by locking nut 16.The upper end of spiral core 22 is the internal conical surface shape of depression, the lower end of rotation core 20 is the outer conical surface shape of projection, both fit together by the technology cooperation, and the locking nut 16 on the central shaft 15 can be guaranteed spiral core 22 and the fitness that rotates core 20.What particularly point out is that rotation core 20 rotates with central shaft 15, and spiral core 22 does not rotate.

The axle center of central shaft 15 is dark blind hole shape structure, circulating cooling water pipe 13 in being provided with in it, and its end is provided with the swivel joint 14 that matches with interior circulating cooling water pipe 13, constitutes the interior circulating water cooling system of die head thus.Cooling water is flowed in the interior circulating cooling water pipe 13 by the water inlet of swivel joint 14, flow out on blind hole top at central shaft 15, blind hole inwall along central shaft 15 refluxes downwards again, and the delivery port by swivel joint 14 flows out at last, constitutes a water-cooled cyclic process of finishing.

Above-mentioned outer body portion mainly is made up of interior die sleeve 21, outer die casing 19 and a mouthful die sleeve 23.Interior die sleeve 21 is close on the outer wall that is sleeved on spiral core 22, with its interference fits.Outer die casing 19 is close on the outer wall that is sleeved on interior die sleeve 21, with its interference fits.The outside of the top of die sleeve 21 and outer die casing 19, rotation core 20 in mouth die sleeve 23 is arranged in.The upper surface of interior die sleeve 21 is ring platform shape, and the lower surface of mouthful die sleeve 23 is encircles platform shape, and both finely tune the location by longitudinal bolt 35 fastening being connected as a single entity by cross bolts 36.

Be provided with outer circulation cooling water channel 12 between the inwall of the outer wall of interior die sleeve 21 and outer die casing 19.Outer circulation cooling water channel 12 is formed by connecting by 32, the 33 and 315 ° of annular water tanks 34 of two spiral tanks on die sleeve 21 outer walls in being opened in, wherein the lower end of a spiral tank 32 intakes with die sleeve, and interface 27 links to each other, the lower end of another spiral tank 33 links to each other with die sleeve water outlet interface 40, and the upper end of two spiral tanks 32,33 links to each other with the two ends of 315 ° of annular water tanks 34 respectively.Constitute the outer circulation water-cooling system of die head thus, the technology fitness of interior die sleeve 21 and outer die casing 19 can guarantee the sealing property of whole die sleeve.

Offer spiral recirculated cooling water road 37 in the barrel of mouth die sleeve 23.In order to process smooth qualified spiral recirculated cooling water road 37, mouth die sleeve 23 can be split into four processing, and then it is welded as a whole.The two ends in spiral recirculated cooling water road 37 through port die sleeve water inlet interface 25 respectively link to each other with the recirculated cooling water source in the external world with a mouthful die sleeve water outlet interface 26.Spiral recirculated cooling water road 37 can be used as replenishing of outer circulation cooling water channel 12, jointly die head is carried out effective water-cooled temperature control.

Logistics of common formation and shaping channel between the outer wall of the inwall of above-mentioned interior die sleeve 21 and mouthful die sleeve 23 and spiral core 22 and rotation core 20, logistics and shaping channel are made up of herringbone feed well 10, spirality feeding groove 11, annular gap buffer strip 29, tapering type conical surface passage 30, annular lax material chamber 8 and last profiled section gap 31 from bottom to top successively.Wherein: herringbone feed well 10 is made of a semicircle annular groove 38 and two pilot trench of falling the herringbone 39 of being opened on spiral core 22 outer walls, and the two ends of semicircle annular groove 38 link to each other with the top of two pilot trench of falling the herringbone 39 respectively.Spirality feeding groove 11 is provided with four, and the bottom of two pilot trench of falling the herringbone 39 links to each other with the lower end of four spirality feeding grooves 11 respectively, and the upper end of four spirality feeding grooves 11 then links to each other with annular gap buffer strip 29.The tapering type conical surface passage 30 of annular gap buffer strip 29 and top thereof, annular relax and expect that chamber 8 and last profiled section gap 31 are used to finish the pressurization again of material, reduce pressure and extrude the blowfilm shaping process.

Above-mentioned core part and outer body portion integral body are seated on the die head base 17, can interior die sleeve 21 and die head base 17 be connected as a single entity with fastening bolt, and 17 of die head bases are fixed on the connecting plate 3 by fastening bolt.Motor 2 also is installed on connecting plate 3, the output of motor 2 is by linking to each other with pinion 4, the lower end of central shaft 15 is passed connecting plate 3 and is linked to each other with gear wheel 5, pinion 4 is a driving gear, gear wheel 5 is a driven gear, both engagement fit, thus the rotation core 20 that drives central shaft 15 and upper end thereof rotates with respect to spiral core 22.

On die head base 17, be provided with horizontally disposed air inlet passage 18, on spiral core 22, offer vertically arranged air center-aisle 7, on rotation core 20, offer horizontally disposed air circular passage 9 and vertically arranged air outlet passageway 24.Above-mentioned air inlet passage 18, air center-aisle 7, air circular passage 9 and air outlet passageway 24 are communicated with successively, and its effect is to feed compressed air, to finish the last blown film process of die head.

On spiral core 22, also offer the sensor placed hole 6 that extends to rotation core 20 lower end outer conical surface from bottom to top, be used for mounting temperature sensor, to monitor at any time and to feed back die head temperature, thereby the heating system that cooperates inside and outside circulating water cooling system and die head maintains in the scope of design the technological temperature of blown film material.

Inflation film manufacturing machine rotating die head of the present utility model is that unsettled being installed on the screw extruder used.The screw tube output 1 of screw extruder passes outer die casing 19 and is threaded on the interior die sleeve 21, and is connected with herringbone feed well 10.Its course of work is as follows:

One, starch biological degradation material is after the screw extruder preplasticizing, clamp-on herringbone feed well 10 by screw tube output 1, material flows through the semicircle annular groove 38 of herringbone feed well 10 earlier, flow into the top of two pilot trench of falling the herringbone 39 then at the two ends of semicircle annular groove 38, flow to the bottom of two pilot trench of falling the herringbone 39 again, like this through two not distribution of runner in the same way, material one is become two, two become four, material is subjected to the variation that the effect of extrusion pressure and speed will produce speed and pressure, under the prerequisite that guarantees flow and flow velocity material evenly is transported in the spirality feeding groove 11.The main effect of spirality feeding groove 11 is the stress that changes in the material structure, makes material temperature more even on the one hand, makes material further plasticizing in process of flowing on the other hand, for final blowfilm shaping is got ready.

Two, the material that flows out from spirality feeding groove 11 at first enters annular gap buffer strip 29, and material can reach the uniform state of a kind of freedom at this release pressure.Material enters tapering type conical surface passage 30 and the lax material of annular chamber 8 then successively, and meanwhile, motor 2 drives central shaft 15 and rotates by pinion 4, gear wheel 5, drives the rotation core 20 slow turns of its upper end, and its rotary speed is approximately 2RPM.Under the double action of extrusion pressure and rotation core 20, material has been finished at this and has been rebulid the pressure and the process of release pressure once more, can make material have even temperature, pressure and flow velocity more so repeatedly, for blowfilm shaping is created best condition.Why core 20 is rotated in use, be because big, the mobile difference of the viscosity of starch biological degradation material has caused discontinuity of material, in die head, must constantly reduce and eliminate the inhomogeneities of material, so just can make material in the blown film process, reach a state preferably, improve the quality and the yields of product.When material is extruded through last profiled section gap 31,, make the distribution of material more even, for final blown film is had laid a good foundation because the internal stress and the velocity deviation of material have effectively been eliminated in the rotation of rotation core rod 20.

Three, in material flow in the process of the logistics of rotating die head and shaping channel, be arranged on interior circulating cooling water pipe 13 in central shaft 15 blind holes, be arranged in outer circulation cooling water channel 12 between die sleeve 21 and the outer die casing 19 and the spiral recirculated cooling water road 37 that is arranged in mouthful die sleeve 23 barrels also open simultaneously, die head and material are carried out the water-cooled temperature control.Why to design so many water-cooling circulating system, be because the viscosity of starch biological degradation material is big, mobile poor equally, material is after screw extruder is clamp-oned die head, include a large amount of fricting shearing heat, and it is too fast from heating up in flowing forming process thereafter, sensitiveness to technological temperature is also higher, causes the material sex change easily, must adopt synergistic mode that its temperature is controlled in the reasonable range all the time.Can be by being installed in temperature sensor monitoring in time and the feedback die head temperature in the sensor placed hole 6, for the flow velocity of recirculated cooling water, flow parameter is regulated that foundation is provided.

Four, the material of extruding from last profiled section gap 31 is to a machining state that adapts to very much film forming, meanwhile compressed air is from 24 ejections of air outlet passageway, under compressed-air actuated effect, make that just having extruded film cylinder thicker, that temperature is higher expands rapidly, formation requires the film cylinder of width, this film cylinder passes through the air-cooled effect with the supporting outside vane of rotating die head again, forms finished film.After the operations such as finished film draws through frame and cuts, pressing, rolling, just obtained the film article of rolling.

Claims

1. an inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material comprises core part and outer body portion that concentric is arranged, it is characterized in that:

Described plug portion branch comprises by spring bearing (28) and is sleeved on the spiral core (22) on the central shaft (15) and is fixed on the rotation core (20) of central shaft (15) upper end by locking nut (16), the lower end outer conical surface close fit of the upper end internal conical surface of described spiral core (22) and rotation core (20);

Described outer body portion comprise the interior die sleeve (21) that is sleeved on the spiral core (22), with the outer die casing (19) of interior die sleeve (21) interference fits and the mouth die sleeve (23) that is arranged in rotation core (20) outside, the upper surface of die sleeve (21) is connected as a single entity by fixture with mouthful lower surface of die sleeve (23) in described, is provided with outer circulation cooling water channel (12) between the outer wall of described interior die sleeve (21) and the inwall of outer die casing (19);

Logistics of common formation and shaping channel between the inwall of described interior die sleeve (21) and mouthful die sleeve (23) and the outer wall of spiral core (22) and rotation core (20), described logistics and shaping channel are made up of herringbone feed well (10), spirality feeding groove (11), annular gap buffer strip (29), tapering type conical surface passage (30), annular lax material chamber (8) and last profiled section gap (31) from bottom to top successively;

Described core part and outer body portion integral body are seated on the die head base (17), described die head base (17) is fixed on the connecting plate (3), the lower end of described central shaft (15) is passed connecting plate (3) and is linked to each other with gear wheel (5), also be fixed with motor (2) on the described connecting plate (3), the output of described motor (2) links to each other with pinion (4), described pinion (4) and gear wheel (5) engagement fit, thus the rotation core (20) that drives central shaft (15) and upper end thereof rotates with respect to spiral core (22).

2. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 1, it is characterized in that: the axle center of described central shaft (15) is dark blind hole shape structure, be provided with interior circulating cooling water pipe (13) in it, its end is provided with the swivel joint (14) that matches with interior circulating cooling water pipe (13).

3. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 1 and 2 is characterized in that: described outer circulation cooling water channel (12) is formed by connecting by two the spiral tanks (32,33) and one the 315 ° annular water tanks (34) that are opened on interior die sleeve (21) outer wall; Wherein the lower end of a spiral tank (32) intakes with die sleeve, and interface (27) links to each other, the lower end of another spiral tank (33) links to each other with die sleeve water outlet interface (40), and the upper end of two spiral tanks (32,33) links to each other with the two ends of 315 ° of annular water tanks (34) respectively.

4. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 1 and 2 is characterized in that: offer spiral recirculated cooling water road (37) in the barrel of described mouthful of die sleeve (23).

5. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 3 is characterized in that: offer spiral recirculated cooling water road (37) in the barrel of described mouthful of die sleeve (23).

6. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 1 and 2, it is characterized in that: described herringbone feed well (10) is made of the semicircle annular groove (38) and two pilot trench of falling the herringbone (39) that are opened on spiral core (22) outer wall, and the two ends of described semicircle annular groove (38) link to each other with the top of two pilot trench of falling the herringbone (39) respectively; Described spirality feeding groove (11) has four, and the bottom of described two pilot trench of falling the herringbone (39) links to each other with four spirality feeding grooves (11) respectively.

7. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 3, it is characterized in that: described herringbone feed well (10) is made of the semicircle annular groove (38) and two pilot trench of falling the herringbone (39) that are opened on spiral core (22) outer wall, and the two ends of described semicircle annular groove (38) link to each other with the top of two pilot trench of falling the herringbone (39) respectively; Described spirality feeding groove (11) has four, and the bottom of described two pilot trench of falling the herringbone (39) links to each other with four spirality feeding grooves (11) respectively.

8. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 4, it is characterized in that: described herringbone feed well (10) is made of the semicircle annular groove (38) and two pilot trench of falling the herringbone (39) that are opened on spiral core (22) outer wall, and the two ends of described semicircle annular groove (38) link to each other with the top of two pilot trench of falling the herringbone (39) respectively; Described spirality feeding groove (11) has four, and the bottom of described two pilot trench of falling the herringbone (39) links to each other with four spirality feeding grooves (11) respectively.

9. the inflation film manufacturing machine rotating die head that is suitable for starch biological degradation material according to claim 5, it is characterized in that: described herringbone feed well (10) is made of the semicircle annular groove (38) and two pilot trench of falling the herringbone (39) that are opened on spiral core (22) outer wall, and the two ends of described semicircle annular groove (38) link to each other with the top of two pilot trench of falling the herringbone (39) respectively; Described spirality feeding groove (11) has four, and the bottom of described two pilot trench of falling the herringbone (39) links to each other with four spirality feeding grooves (11) respectively.