Static mixer for production of curable mixtures from liquid components, and its use

The present invention relates to the static stirrer of the curable mixed product according to claim 1 of the claims and the usage of the stirrer.

Agitators that develop at least two fluid components are described in EP-A-0749776 and EP-A-0815929. Despite their small size, these stirrers are designed to be simple and material-saving, and in fact despite the agitation of highly viscous materials such as sealants, two-component foam materials or two-component adhesives. Produces good stirring results. The stationary member forming the stirring structure can be manufactured at a favorable price by injection molding a thermoplastic material so that it can be used once and disposable from the viewpoint of economy. Such "disposable stirrers" are primarily used in curable products. The reason is that it is practically impossible to clean the stirrer when using those products.

However, even when the disposable stirrer stirs the curable mixture continuously or semi-continuously (eg, in a cycle), the service life is limited. For example, if continuous agitation is performed under conditions where the extrusion pressure is kept approximately constant, i.e., if there is some pressure drop along the stationary member of the agitator, the agitated product emissions will be used. It decreases significantly with time. Increased extrusion pressure can only prolong the discharge of agitated products for a relatively short period of time.

<p> An object of the present invention is to provide an improved stirrer that gives the disposable stirrer a long service life. This object is achieved by the stirrer according to claim 1.</p>

<p> This static stirrer is used for curable mixed products with fluid components that react by mixing to form solidified bodies. This stirrer is manufactured by injection molding<u style="single">Installation</u>Enclose the placement member and its placement member<u style="single">Ruchi</u>Including with the tube. Stationary members are in multiple mixing chambers<u style="single">Have.</u>Mixing chambers back and forth along the tube axis<u style="single">Left and right</u>Arranged side by side. Those rooms<u style="single">, The radial direction of the tube and</u>Tube axis direction<u style="single">Radius extending to</u>Long wall and<u style="single">A longitudinal wall extending in the direction of the tube axis,</u>Cross the tube axis<u style="single">Extend in the direction of</u>It is defined by a cross wall.<u style="single">With the radial longitudinal wall and the longitudinal wall between the mixing chambers</u>The openings formed in the mixture form the inlet and outlet of the mixed product.<u style="single">Also, two parallel outer longitudinal walls extending in the direction of the tube axis are the first pair of mixing chambers.</u>Form the outer surface. At least some mixing chambers<u style="single">With respect to, a first corner fillet partially filled with wall material is formed at the corner of the connection between one cross wall and one first outer surface, and the first corner fillet is mixed. A first concave surface is formed with respect to the internal space of the chamber, and the cross-sectional shape of the first concave surface is curved in a concave shape and is connected to the one first outer surface and the one cross wall. ing</u></p><p> In the present specification, the "concave surface" means a surface on which a convex surface portion is not formed toward the internal space of the mixing chamber at any location. This surface can be partially flat. This concave surface is curved in a concave shape<u style="single">Re, sideways</u>A song curved in a concave shape in the cross section<u style="single">Line part</u>It forms a "concave portion" to have. The small wedge-shaped corner fillets form an example of a concave surface in the second sense.</p><p> Dependent claims 2 to claims<u style="single">8</u>Represents an advantageous embodiment of the stirrer of the present invention. The usage of this stirrer according to the present invention is claimed.<u style="single">9</u>It is described in.</p><p> The static stirrer is known in US-A2004 / 0008576, the stationary member of which is similar to the stationary member of the stirrer of the present invention, but the fillet of the corresponding corner is wedge-shaped, as described above. It is not concave in the specified sense. The shape of those corner fillets is not preferable for extending the service life. Another drawback is that the wedge-shaped corner fillets mean a relatively large agglomerate of wall material. Aggregation of such materials is not preferable for injection molding the stationary member. This is because it lengthens the manufacturing cycle and increases the manufacturing cost.</p><p> The present invention will be described below with reference to the accompanying drawings.</p>

The stirring structure shown in cross section in FIG. 1 of a disposable stirrer known from the publication of EP-A-0749776 is a stationary member 1, which is manufactured by injection molding and is a tube (shown). Is inserted in). This tube surrounding the stationary member 1 has an internal space having a square cross section, and the stationary member 1 is fitted therein so as to match the shape. (The stationary member 1 and the surrounding tube can also be formed in a cylindrical shape, see, for example, Figure 3). The components of the fluid curable mixture are swept from the cartridge through the tube and stationary member 1 by a piston, and the reactive components of the mixture are mixed to form a solidified object. The stationary member 1 has a chamber arrangement including a plurality of mixing chambers 2. Mixing chambers 2 move back and forth along tube axis 10<u style="single">Left and right</u>They are arranged side by side in. Mixing chamber 2 is a tube<u style="single">Radial direction and tube</u>Axis 10 direction<u style="single">Extend to</u>Half<u style="single">Diameter length</u>Hand wall<u style="single">3b, 3d and the longitudinal walls 3a, 3c extending in the direction of the tube axis,</u>Cross the tube axis<u style="single">Extend in the direction</u>It is defined by the cross walls 4a and 4b. Half between mixing room 2<u style="single">Diameter length</u>Hand wall<u style="single">3b, 3d and longitudinal walls 3a, 3c</u>The openings 5a, 5b, 5c, 5d formed in are the inlet and outlet of the mixed product. The first outer surface 6a of the mixing chamber 2 is formed by two parallel outer longitudinal walls 6. Each of the mixing chambers 2 has a second outer surface 6b between their longitudinal walls 6 which is open and not bounded by tubes (not shown). The outer longitudinal wall 6 can also be omitted.<u style="single">Often</u>In the embodiment used, the outer longitudinal wall 6 forms the first outer surface 6a.

The mixing chamber 2 formed by the present invention is shown in FIG. The feed of the mixed product through the mixing chamber 2 is also indicated by an arrow. The inlet 5a into which the mixed product flow 12a flows in is located on the inlet side in the immediate vicinity of the cross wall 4a (see Figure 1). Flow 12b flows in through the second inlet 5b. The flow 12a branches into branch flows 12ad and 12ac, and those branch flows flow into the adjacent mixing chamber through outlets 5d and 5c. The flow 12b also branches into the branch flows 12bd, 12bc, and those branch flows exit the mixing chamber, which is fully shown in FIG. 2, together with the branch flows 12ad, 12ac.

A pressure gradient state is formed in the mixing chamber 2 by the pressure of the mixed product passing through the stationary member 1. This pressure gradient forms the velocity state of the mixed product flow. This pressure gradient is most emphasized in the region of openings 5a, 5b, 5c, 5d where the flow velocity is also maximum. The flow can be thought of as a bundle of streamlines. The cross section of the streamline in the mixing chamber 2 is wide and therefore has a relatively slow flow velocity. Therefore, the pressure gradient is also small. The decrease in pressure gradient depends on the position. The pressure gradient is very small, especially in the corner region farthest from the openings 5a, 5b, 5c, 5d. In reality, the pressure gradient there disappears and the flow of the mixed product is very slow and actually stagnant. A reaction occurs between the components of the mixed product in the mixing chamber where the agitation has already progressed significantly. This increases the viscosity of the mixed product in areas where the flow is stagnant. The stagnant region increases due to changes in viscosity, and local immobilization is inevitable. This fluidization begins in the corner region and extends from there to the internal region of the mixing chamber 2. As a result, the flow resistance of the stationary member 1 also increases. The mixture is mixed and the condition is deteriorated at the same time.

The fact that agitation with a disposable stirrer can only be performed during the service life determined by the reaction of the curable mixture is associated with the occurrence of this fluidization. Service life can be extended when the stagnation of fluidized mixed products is addressed. Such a countermeasure is an improvement according to the present invention of the mixing chamber 2 shown in FIG. The improvements are as follows.

On the exit side, the cross wall 4b and the outer longitudinal wall 6 include a corner filled with wall material, which corner is the cross wall.<u style="single">To 4b</u>It is shown as a "tripod" drawn with a chain line. The fillet of this corner, referred to as the "first corner fillet 7," forms a concave surface 7a (according to the above meaning) with respect to the internal space of the mixing chamber 2. As is clear from FIG. 2, the stagnation situation is eliminated by the first corner fillet 7, which results in extended service life.

Further measures to form the "second corner fillet 8" further contributed to the extension of service life, in which the cross wall 4a and the second outer surface 6b in the mixing chamber 2 were cornered with wall material. The fillet, that is, the second corner fillet 8, also forms a concave surface 8a with respect to the internal space of the mixing chamber 2. The action of the second corner fillet 8 is the same as that of the first corner fillet 7.

If this problem is not addressed, or if the same is addressed everywhere, the fluidization will be more pronounced as the mixing chamber 2 is located downstream. Therefore, the first and / or second corner fillets 7,8 are made to at least partially different dimensions, and the corner fillet 7 or corner fillet 8 is the downstream corner fillet 7 or corner fillet 7. It is advantageous to be formed as large as or smaller than 8.

Corner fillets 7, 8 must not form agglomerates of material that are too large. The reason has already been mentioned above. Therefore, it would be advantageous to apply the following to the first corner fillet 7 (and thus the second corner fillet 8). That is, each of the concave surfaces 7a (or 8a) joins the flat portion 4b'(or 4a') of the cross wall 4b (or 4a) at the boundary line 7b, and this boundary line 7b is the intermediate strip of the cross wall 4b. It should be located in, and this strip occupies the central 1/3 of the cross wall 4b inside it.

The concave surface 7a or the concave surface 8a each forms at least a substantially cylindrical part. This cylindrical axis is located in a plane oriented at right angles to the tube axis 10. The cylindrical axes that combine the two corner fillets 7 and 8 are aligned at right angles to each other.

The concave surfaces 7a and 8a smoothly merge into the flat portion 4a'or 4b'of the cross wall 4a or 4b, respectively. The same applies to the confluence of the mixing chamber 2 to the plane on which the outer surface 6a or 6b is located.

The second outer surface 6b of the mixing chamber 2 is covered with a second corner fillet in an area area no larger than the inlet 5a that forms the boundary on the cross wall 4a. This condition is caused by the geometry of the tool used as a mold in injection molding.

The cylindrical stationary member of the stirrer according to the invention is shown in FIG. 3, which has first and second corner fillets 7,8. The outer longitudinal wall 6 forming the first outer surface 6a of the mixing chamber has a circular segmental cross section. The second outer surface 6b is curved. Therefore, one flank of the second corner fillet 8 is also curved.

Due to its use by this stirrer, the mixed product of components that react to mix to form a coagulum is maintained or varied approximately throughout the cycle, i.e. the stationary member 1 of the stirrer. It is favorably agitated continuously or semi-continuously by the extrusion pressure that drops along the pressure. If the discharge of the mixed product is significantly reduced or the extrusion pressure needs to be increased, the stirring is stopped immediately and the stirrer is replaced.

<figref num="1">Partial perspective view showing the stirring structure (stationary member) of a known disposable stirrer.</figref><figref num="2">A partial perspective view showing a mixing chamber of a stirrer according to the present invention.</figref><figref num="3">A partial perspective view showing a cylindrical stationary member of a stirrer according to the present invention.</figref>

Code description

1 Stationary member 2 Mixing room<u style="single">3b, 3d radial longitudinal wall</u><u style="single">3a, 3c Longitudinal wall</u> 4a, 4b cross wall 4a', 4b'planar part 5a, 5b, 5c, 5d openings 6 Outer longitudinal wall 6a First outer surface 6b Second outer surface 7 First corner fillet 7a concave 7b border 8 Second corner fillet 8a concave 10 tube axis 12a, 12b flow 12ad, 12ac, 12bd, 12bc Branch flow