CN1985684A - Floating meshed double screw vermicelli and food extruder - Google Patents

Abstract

The present invention is a kind of floating meshed double screw extruder for producing rice vermicelli. It may be used in continuous production of rice vermicelli as well as other nutrient reinforced food, such as functional seaweed food. It has high temperature and high pressure food material extruding process to denature the food material and raise the nutritious value. It has reasonably designed lead screw length/diameter ratio, compression ratio, screw angle, cross section shape, screw rotation directions and vermicelli spraying board structure.

Description

Floating meshed double screw vermicelli and food extruder

The present invention relates to a kind of structure of floating meshed double screw vermicelli and food extruder.

To be that China south people are special like one of cuisines of eating to known ground rice silk, and how by hand or half mechanical-moulded traditional cereal powder process silk, and production efficiency is low, and is of low quality.Adopt novel screw extruder, cereal is ground powder earlier, water mixing is mixed, and is squeezed into silk in the input machine, can realize continuous industry production, stable and reliable product quality, highly efficient in productivity, also can change single cereal materials, produce functional food, increase fortifiers such as marine alga.

Single-screw extrusion machine (Single-Screw extruder) is used for the synthetic fibers spinning more, and the throwing of incompatibility cereal because of it is by the defeated material of friction, when the bigger frictional force of moisture content descends, causes difficult feed, " loops " clogging occurs.Material easily adheres on the screw rod, because it lacks self-cleaning ability.Energy consumption is also big, about 900～1500KJ/kg.

Twin (double) screw extruder (Twin-Screw extruder), its performance is more suitable in the vermicelli and food extrusion modling than single screw rod, because it is between two parallel screws, meshes in the same way or oppositely, in barrel, force convey materials, be difficult for producing leakage current and " loops " phenomenon.Because of fine self-cleaning action is arranged, can avoid per tour disassemble cleaning in the existing production.About 400～the 600KJ/kg of energy consumption is half of single screw rod, greatly saves energy.

At present, our employed twin (double) screw extruder is non-engagement type, lacks material between two screw rods and kneads mutually, screw slenderness ratio (L/D) and compression ratio are not enough in addition, produce with three series connection, and floor space is big, takes the labour, when taking a lot of work, every class to clean, disassemble and assemble work extremely bothers.In addition, the transmission reduction box rigid attachment of two screw rods and two shafts requires the centre-to-centre spacing and the depth of parallelism strict conformance of two shafts of two screw rod centre-to-centre spacing and the depth of parallelism and reduction box.Difficulty reaches in the manufacturing, and remedies with the gap that enlarges screw rod and barrel, leakage current as a result, and quality of item is poor.

The present invention seeks to:, make heating, slaking and extrusion modling in an engagement type twin-screw machine barrel, one-shot forming in short-term according to the characteristic of starch biopolymer.Change the positive drive connection into the aligning that can move about, screw engages is in the material floats.Also can make the special screw-rod structure that is fit to the functional sea food requirement according to production technology.

Two diameters are identical, and the screw rod of flight land engagement type is installed in parallel in the machine barrel that is " δ " font inner chamber.The external diameter of screw rod is slightly larger than machine barrel inner chamber two pitch-rows, its gap: δ=H-R-r

---two screw rods centre-to-centre spacing R---screw rod exradius r---screw rod spiral shell root radius in the formula: H

Gap delta is meant the gap of wanting should leave between the spiral shell root minimum of spiral shell item and another root screw rod of a screw rod, guarantees the requirement of installing.

Two screw rods become an integral body in the engagement of machine barrel " δ " font inner chamber.Transmission case only has two parallel axes, and reduction box is separated, and is another integral body.Then, with two integral body that centre-to-centre spacing is identical, but with the shaft coupling of aligning, couple together transmission.When between screw rod, be full of thing section, screw rod be in the material bag former in, rotate freely under the state of the engagement of floating.The precision of screw rod and barrel can be very high, and the gap is very little, and leakage current is little, and quality of item improves thereupon, and originally the drawback brought of rigid attachment overcomes thereupon.

For easy to process, screw rod is designed to equidistantly not wait dark whole screw rod, and cost is low, and the operating characteristic of the transmission that is meshing with each other easily reaches.Machine barrel is whole alloy-steel casting.Have on the screw rod: " feed zone ", " compression section ", " homogenizing zone ".Feed zone accounts for 1.5 pitch, and the compression section accounts for total length 35%～45%, and surplus is homogenizing zone.The degree of depth of compression section screw thread, by the degree of depth of feed zone, the degree of depth of the homogenizing zone that shoals gradually promptly forms the material spatial volume and dwindles gradually, produces volume compression, and pressure rises thereupon, has strengthened kneading, shear action to material in the machine drum body.Extrusion process is the chemical process of a power, mainly in this section generation.The cereal main component is a starch, and under extruding, shearing, mixing power effect, internal stress concentrates on indivedual segments of starch polymer, produce limit stress, make the chemical chain fracture of starch polymer, formed some free group active particle, produce new matter structure.Producing closely related with this bean vermicelli is " gelation ".The gelation process of starch granules in extruder is very complicated.When starch by original compact ordered structure, become loose unordered structure, i.e. starch generation gelatinization becomes " gelatinized corn starch ".The essence of starch gelatinization is that the hydrogen chain of amylum body is destroyed, and starch crystals has partly lost its crystalline texture.Obviously " gelatinized corn starch " will have a strong impact on boiling of throwing food and mouthfeel.When this is the length of design screw compression section and compression ratio, the process aspect problem that must attract great attention.In the synthetic fibers spinning, screw slenderness ratio (L/D) and compression ratio are all very big, as terylene L/D=25, and compression ratio 2.5～3.5; Polypropylene fibre L/D=30, compression ratio 3.5～5.This is the melting process that is fit to the high polymer spinning.Starch belongs to biopolymer, does not have melting in the throwing process, thereby intends with little draw ratio, does not generally surpass 10 and little compression ratio, and as about 1.5, reasonable control can prevent the generation of gelation " gelatinized corn starch ".

The helical angle Φ of screw rod, the functional characteristic of decision screw rod, because material borrows it to advance, the present can be with reference to the synthetic fibers spinning, employing pitch S equals screw diameter D, corresponding helical angle Φ=17 ° 39 '.

Work as S=D, Φ=tan ^-1(S/ π D)=17 ° 39 '

The shape of screw rod section has rectangle and zigzag, and the latter can improve screw strength, avoids dead angle material stock phenomenon.The anterior angle of screw thread zero anterior angle, even use negative rake, can better advance material.

Two screw rods have been meshing with each other and have rotated in the same way and two kinds of forms of reverse rotation, reverse and outer reverse engagement in oppositely having again.

When the direction of two screw spirals is identical, to rotate when meshing in the same way, its advantage is that self-cleaning ability is strong, promptly material is difficult to adhere on the screw rod.Because of the luer engages with place, there is the very big opposite speed difference of direction in a land with another root spiral shell root.In addition, the route that material advances is along two screw channel mutual connections, is " 8 " Pear-Shaped profile and advances, and changes the next one over to by previous Pear-Shaped, and obviously route is very long, and mixing of materials is got evenly.

The direction of rotation of working as two screw flights again is opposite, and when oppositely meshing outward, material is divided into and is the chamber propelling of " C " shape material, and the speed difference between a screw rod top and another root screw rod root is little, the self-cleaning ability respective differences.But its advantage is also arranged, and more even than what mesh in the same way in discharging opening discharge along the circumferential direction, it becomes the uniformity of silk beneficial to bean vermicelli.

The structure of screw head becomes silk in close relations with shower nozzle.It is a material when leaving screw channel and entering the shower nozzle runner, and the materials flow form sharply changes, by the rotation motion motion that is in line.For fear of producing dead angle nest material, screw head is made cup head or conical head.

The engagement owing to float, the gap of screw rod and machine barrel only 0.2～0.6, when making with 38CrMoAlA high-quality steel, nitrogen treatment after the fine finishining, 0.4～0.7 centimetre of nitration case, case hardness HV850 above (Rockwell hardness is greater than HRC65), a little higher than screw rod of barrel case hardness, so high hardness helps long-term operation.

Moisture content should strictly be controlled in the material, and water has plastication, can reduce screw driven power consumption.But water also has foaming effect, and machine barrel exit water-cooled is to prevent the material depanning, and pressure descends suddenly when temperature is high, and water vapour expands rapidly and distributes, and flash distillation forms loose structure.Opposite, dilated food wishes to form this microcellular structure, be that these goods are undesirable, thereby there is water-cooling structure in the machine barrel exit.

In addition, be reinforced thing (as marine alga etc.) and will carry out strict screening and conscientious preliminary treatment, just can mix extrusion process, see my " shark functional food of fortification " number of patent application for details: 02122523.0 reaches " the dried green alga-soybean milk bamboo of fortification " number of patent application: 98126471.9.The fortifier incorporation is no more than 10% usually.

Below further illustrate detailed structure of the present invention more in conjunction with the embodiments.As shown in Figure 1.

Illustrate two and equidistantly do not wait dark screw rod 8At machine barrel 7Middle engagement is illustrated as two homodromal spiral shell ribs, near charging aperture 9One section screw thread dark, shoal gradually to discharging opening, the middle space that forms reduces gradually, the material kneading is subjected to shearing stress, makes the new matter structure of starch biopolymerization deposits yields.Logical then more shallow homogenizing zone is delivered to spinning head with material.Spinning head 1With machine barrel 7End face link, the homogenizing plate is wherein arranged 4, pressure equalising space 3, spinneret 2Form.The place is provided with pressure sensor at pressure equalising space 5, pressure signal is delivered to instrument, realize control, electromechanical automatically.At machine barrel 7Discharge end, be provided with cooling water jecket 6, enter spinning head after making material appropriateness cooling, prevent that material goes out spinneret under the high temperature, the moisture content flash distillation forms micropore.

Twin-screw 8Be to borrow two shaft transmission cases that go out 11Drive, two parallel axes are only arranged, designs simplification in the transmission case.The driven by motor reduction box is again with two chain drive transmission cases.The structure of transmission case is limited by the strictness of two screw rod centre-to-centre spacing, matches with it.The reduction box complex structure, rapid wear, after separating, buyable.

Twin-screw 8Go out shaft transmission case with two 11Between, but with the cross plate shaft coupling of two pairs of alignings 10Link.Because the screw rod rotary feeding has very big back thrust, can make cross plate be difficult to move about, thereby two sides all has roller about cross plate, and has outer sleeve anti-drop to open.Should transmit moment of torsion, bear very big axial thrust again, both will satisfy simultaneously, are the particularity of this shaft coupling.

Because twin-screw 8At machine barrel 7In engagement, the centre is full of material, the front and back of screw rod all do not have bearing constraint, are in the material parcel and float down, effectively eliminate many drawbacks that former rigid attachment transmission brings.

Two screw rods 8Outer diameter D identical, greater than machine barrel 7Two pitch-row H, thereby the spiral shell rib of two screw rods engagement obtains good kneading and mixes effect, and tough and tensile can the standing of goods boiled, any surface finish exquisiteness obtains good mouthfeel.

To sum up state the twin-screw engagement type, significantly more energy-conservation than the non-engagement of original twin-screw, and disposable formation goods, significantly improve than the effect of original three series connection.Extruded food is the developing direction of modern food, has accounted for 50% more than of food total amount in the country that has, is in more and more prosperously, in the ascendant in China, and it is except improving food quality, enriching people's the life, and more important is energy-conservation.By the development trend of modern functions food, can carry out fortification in the technical recipe, produce (as the marine alga condensed foods) such as functional food, the series of products with the healthy closely bound up squeeze function food of people's life is provided.

Claims (6)

1, the present invention relates to a kind of structure of floating meshed double screw vermicelli and food extruder, it is characterized in that: two are not equidistantly waited dark screw rod 8, be installed in parallel in the machine barrel of figure of eight inner chamber 7In engaged transmission, material is from charging aperture 9Drop into, through (as shown in the figure) or reverse thread in the same way material is again and again kneaded, and push ahead with screw channel, the space dwindles gradually, and material pressure increases gradually, and the head by screw rod enters the homogenizing plate then 4The hole in, enter pressure equalising space again 3, at last from spinneret 2The hole in, be sprayed into bean vermicelli and portal; The pressure equalising space place is equipped with pressure sensor 5, the numerical value of demonstration pressure; Two screw rods 8Respectively by the cross plate shaft coupling 10Transmission, a side of cross plate is connected with the power transmission shaft of one 12Two parallel power transmission shafts 12, borrow bearing to be installed in transmission case 11In, transmit power from motor and deceleration, speed change gear.

2, right 1The screw rod of described floating meshed double screw vermicelli and food extruder 8Feature also be: the engagement of two screw flight faceted pebbles, the outer diameter D of screw rod is slightly larger than the pitch-row H of machine barrel 7 endoporus, forms two screw flight faceted pebbles and inserts mutually, but leave gap delta; The screw flight shape can be by the requirement of processing materials design, is illustrated as equidistantly not to wait deeply, and has feed zone darker, and the compression section shoals gradually, to homogenizing zone be shallow slot, the formation compression ratio; Helical angle Φ decision screw rod functional characteristic as adopting S=D, illustrates two screw rods 8Be homodromal spiral shell rib, two reverse spiral shell ribs (not drawing as yet among the figure) are also arranged.

3, according to the machine barrel of right 1 described floating meshed double screw vermicelli and food extruder 7Be characterised in that: inner chamber is the figure of eight, and base is arranged outward, on charging aperture is arranged 9, there is cooling water jecket in the front end outside 6, the spinneret headgear is equipped with in the place ahead 1

4, according to the described headgear of claim 3 1Be characterised in that: one side and machine barrel 7Link, the homogenizing plate is equipped with in the centre 4And spinneret 2

5, according to the described cross plate of claim 1 10Be characterised in that: borrow the intermediate module of cross plate three assemblies, transmit the moment of torsion of two sides, can float automatically again, regulate the nonconcentricity deviation in installing.

6, want 1 described transmission case according to right 11Be characterised in that: have two parallel axes 12, borrow bearing to be installed in the housing of transmission case, with transferring power.