JPS5954005B2 - Continuous kneading machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous kneader that can provide uniform kneading.

Generally, when kneading polymeric substances such as synthetic resins, a continuous kneader that can continuously supply, knead, and discharge materials is used in order to shorten kneading time and improve productivity. In particular, twin-screw continuous kneaders are popular because they have a higher melting effect due to shear heat than single-screw kneaders and can improve kneading efficiency. By the way, when this twin-screw type continuous kneading machine is used, a so-called short bath phenomenon occurs in which a part of the material passes through the kneading section with almost no shearing action, depending on the type of material and the mixing ratio. In some cases, this may impede the uniformity of kneading and deteriorate the quality of the product.

In view of these circumstances, the present invention aims to improve the quality of products by preventing the short bath phenomenon and ensuring uniform kneading while maintaining the effects of a two-screw continuous kneading machine. The purpose is to

In the present invention, two kneading shafts are arranged in parallel in a chamber equipped with a material supply port at one end and a discharge port having a throttle mechanism for adjusting discharge pressure at the other end, and each kneading shaft has a feed section and a
In a continuous kneading machine having a kneading section and a discharge section, arc-shaped weirs are protruded continuously from the bottom inner surface of the chamber corresponding to the discharge section of each kneading shaft in the chamber. The kneaded material J is sent out over this weir, thereby preventing short baths and making it possible to make the kneading uniform.

Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a chamber, which has a material supply port 2 at one end and a discharge port 3 at the other end, and has a hollow section shaped like a cross-section glass inside, and two kneading shafts 4, 4' are installed in the chamber. are arranged in parallel.

The kneading shafts 4, 4' are connected to the feed section 4 in order from the material supply end.
1 and 41', kneading sections 42 and 42', and discharge θ discharge sections 43 and 43'.

The feed sections 41, 41' have a screw shape, and the kneading sections 42, 42' have blades with an oval cross section twisted in a normal thread direction from the starting end side to the middle part, and then twisted in a counter thread direction from the tip to the terminal side. The discharge parts 43, 43' are formed of straight blades having the same cross section as the kneading parts 42, 42'. Corresponding to these parts, feed chambers 11, 11'', kneading chambers 12,
12'' and discharge chambers 13, 13'' are formed,
These chambers are continuous in the axial direction, and adjacent chambers on the left and right in the cross section communicate with each other.

Note that the discharge port 3 is provided with an orifice 5 whose opening degree can be adjusted as a throttle mechanism for adjusting the discharge pressure. In such a continuous kneading machine, the present invention specifically provides weirs 6, 6'' projecting from the bottom inner surface of the discharge chambers 13, 13'' within the chamber 11.

The weirs 6, 6'' have a chevron-shaped cross section, and the chambers 13, 13''
It is formed into a circular arc shape along the circumferential direction of the bottom surface, and the left and right weirs 6, 6'' are formed to be continuous with each other. The weirs 6, 6
'' may be provided integrally protruding from the inner surfaces of the chambers 13, 13'' of the chamber 11, or may be separate pieces that are removably attached using attachment means such as bolts and integrated. On the other hand, in the discharge parts 43, 43'' of the kneading shafts 4, 4'', recesses 44, 44'' are formed in the portions facing the weirs 6, 6'', so that the kneading shafts 4, 4'' can rotate without hindrance. do.

Further, the chamber 1 has at least a portion corresponding to the weirs 6, 6'', in the embodiment, the kneading chambers 12, 12'' and the discharge chambers 13, 13'' are vertically divided, and the kneading shafts 4, 4
To prevent the weirs 6, 6'' from getting in the way when extracting the material from the chamber 11. Next, the operation of the kneader will be explained.

The pellet-like or powder-like mixed material A introduced from the supply port 2 of the chamber 1 is fed into the kneading chambers 12, 12'' in the front by the feed portions 41, 41' of the kneading shafts 4, 4''.
In the kneading chambers 12, 12'', the material A is subjected to the following kneading action.As shown in FIG. (during the rotation, part of the material A is rotated in the opposite direction of the kneading section 42, 42'')
, 42a'', 42''b and the inner surfaces of the kneading chambers 12, 12'', during which time they are subjected to shear heat q, heated up, and melted.

On the other hand, there is an unmelted material in front of the rotation of the kneading section 12, 12'', and further above that there is a material that has been melted by the shearing action of the chip land, etc., and this molten material and unmelted material are separated. The molten material enters the unmelted material at the boundary between the layers, and during this time heat is transferred, melting and kneading.In this case, the above-mentioned clearance is maintained during one rotation of the kneading shafts 4, 4''. The material passing through is a part of the total material A, and most of the other material is in front of the rotation of the kneading sections 42, 42''.

By the rotation of the kneading parts 42, 42'', when the chips pass through the upper wall intersection 12a of the kneading chambers 12, 12'', the molten material, unmelted material, and a part of the mixed material are mixed together. are mixed and discharged into the central space C between the kneading sections 42, 42'', and then distributed to the left and right kneading chambers 12, 12'' by the bottom wall intersection 12b of the kneading chambers 12, 12'', and the following By repeating the above action, the material A is gradually melted and kneaded, and then the material A is transferred to the feed chamber 1.
It is pushed by the subsequent material fed in from 1, 1'' and is sent to the discharge chamber 13, 13'' side. In such a mixed line state, a part of the material discharged into the central space C by the rotation of the kneading sections 42, 42'' as described above is in the middle part or near the end of the kneading chambers 12, 1 and 2''. There is a tendency for the mixture to jump into the discharge chambers 13, 13'' before being distributed to the left and right kneading chambers 12, 12'' by the bottom wall apex 12b, or to flow out to the discharge chambers 13, 13'' immediately after being distributed. .

In this case, if there are no obstacles on the inner wall surface of the chamber, particularly the bottom, and the kneading chamber and the de-staging chamber have uniform cross-sectional shapes, as in the past, water will jump into the de-staging chamber from the middle or near the end of the kneading chamber. , or the material that was about to flow out will simply jump in or flow out without any resistance.

This is the so-called short pass phenomenon, and the short pass material contains unmelted material. The material fed into the discharge chamber in this way is discharged outside the machine through the discharge port by the discharge section.
In this case, there is no active kneading effect, and the product is processed almost as is.
sent out. Therefore, in conventional kneading machines, the unmelted material is sent out of the kneading machine, which is a factor in degrading the quality of the product. However, according to the present invention, since the circular arc-shaped weirs 6, 6'' are continuously protruded from the discharge chambers 13, 13'', the discharging chambers 13, 13'' are provided with circular weirs 6, 6'' that protrude continuously from each other. The material that was about to jump into or flow out from the discharge chamber 13, 13'' hits the weir 6, 6'' and is returned to the kneading chamber 12, 12'', where it is again subjected to the same shearing and melting as described above. , subjected to kneading action.

This makes it possible to prevent the occurrence of shot passes as in the conventional case, shorten the residence time distribution (time difference) of the materials in the kneading chambers 12 and 12'', and make the residence time 1 hour uniform. , the frequency of shearing action, that is, the shear rate value, can be increased, the melting and kneading efficiency can be increased, and sufficient kneading can be achieved.Furthermore, in this case, the kneading chamber 12,
Since short passes are likely to occur at the bottom of the chambers 12'', particularly in the central space C between the two chambers 12, 12'', it is effective to form the weirs 6, 6'' as shown in FIGS. 5 and 6.

That is, in a cross section perpendicular to the axial direction of the chamber 1, the chambers 13, 13'' are divided into the first to fourth quadrants to I by the horizontal center line x and the vertical center line Y, Y'', respectively.
One weir 6 is formed in an arc shape centered on the center point 0 located in the second quadrant 11 of the chamber 13, and the other weir 6'' is formed in the first quadrant 1 of the chamber 13''. The apex 6a of the continuous part of both weirs 6, 6'' is located above the center line x, and the opposite ends 6b, 6b'' By doing so, the short pass phenomenon that tends to occur in the center space C can be more reliably prevented, the melting and kneading efficiency can be further increased, and the kneading can be performed more completely.Kneading chamber 1
The material completely melted and kneaded in the feed chambers 11 and 12'' is pushed by the subsequent material fed from the feed chambers 11 and 1'', overflows the weirs 6 and 6'' and flows into the discharge chamber 1.
3, 13'', and is discharged outside the machine from the discharge port 3 by the discharge portions 43, 43''.

As explained above, according to the present invention, the short pass phenomenon can be prevented by the arc-shaped and mutually continuous weir provided in the discharging chamber, and the residence time of the material in the kneading chamber is made uniform, resulting in variations in the degree of kneading. can be made smaller and the quality of the product can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing an embodiment of the continuous kneading machine of the present invention, Fig. 2 is a cross-sectional plan view thereof, Fig. 3 is a longitudinal sectional side view of the discharging chamber, and Fig. 4 is the same machine showing a mixed line state. FIG. 5 is a vertical side view of the discharge chamber showing another embodiment, and FIG. 6 is a vertical front view of the weir. DESCRIPTION OF SYMBOLS 1...Chamber 1, 2...Material supply port, 3...Discharge port, 4,4''...Kneading shaft, 5...Orifice, 6
,6"...Weir, 11,1"...Feed chamber, 12,
12Z...kneading chamber, 13,13''...discharge chamber, 41,4''...feed section, 42,42''...
Kneading section, 43, 43''... discharging section.

Claims (1)

[Claims] 1 Two kneading shafts are arranged in parallel in a chamber equipped with a material supply port at one end and a discharge port with a throttle mechanism for adjusting discharge pressure at the other end, and each kneading shaft has a feed section, a kneading section, and a discharge section. A two-shaft continuous kneading machine having two shafts is characterized in that arc-shaped weirs are continuous with each other on the inner surface of the bottom of the chamber corresponding to the discharge part of each kneading shaft in the chamber. Continuous kneading machine.