JPH0530897Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention involves colliding and mixing multiple liquid plastic raw materials (hereinafter referred to as stock solutions) at high pressure, feeding them into a mold, and forming plastic products through a chemical reaction. The invention relates to a mixing head for a reaction injection molding machine.

[Prior Art] As this type of mixing head, the one shown in FIGS. 5 and 6 is known.

As shown in FIG. 5, this mixing head moves each stock solution supplied to a plurality of inlet passages 2 from a throttle valve 3 to a mixing chamber 4 by advancing a spool 1.
The liquid is allowed to flow from the upstream side of the throttle valve 3 through the bypass passage 5, the circulation groove 6 formed in the spool 1, and the return passage 7 to a stock solution tank (not shown) without being spouted, and as shown in FIG. Spool 1
By retreating, each inlet passage 2 is opened to the mixing chamber 4, and after each stock solution is jetted into the mixing chamber from each throttle valve 3 and mixed by collision, it flows out into a mold of a molding machine (not shown). I'm starting to let them do it.

In the mixing head configured as described above, by advancing the spool 1, each stock solution can flow into the stock solution tank through the bypass passage 5, the circulation groove 6, and the return passage 7 even during non-molding. This has the advantage that the temperature of the stock solution in the stock solution piping system can always be kept constant.

[Problems to be solved by the invention] However, in the above conventional mixing head,
Since the stock solution supplied to the inlet passage 2 flows from the upstream side of the throttle valve 3 through the bypass passage 5 to the circulation groove 6 side, the flow rate of the stock solution in the vicinity of the throttle valve 3 becomes slow.
When a filler such as glass fiber is mixed in the stock solution, there is a drawback that the filler is deposited on the throttle valve 3. In particular, when the undiluted solution is continuously returned to the undiluted solution tank for a long period of time, such as at night or on holidays, the filler may clog the throttle valve 3 and the undiluted solution cannot be spouted from the throttle valve 3.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a mixing head for a reaction injection molding machine in which fillers and the like are not deposited on the throttle valve.

[Means for Solving the Problems] In order to achieve the above object, the present invention has an inlet passage for individually introducing a plurality of stock solutions into the mixing chamber of the spool insertion hole whose tip side is a mixing chamber. a mixing head main body, a throttle valve provided in the inlet passage of the mixing head main body and for spouting the stock solution into the mixing chamber at high speed; and a spool that opens and closes with respect to the mixing chamber, and a spool on the upstream side of the throttle valve of the inlet passage is provided with a spool that opens and closes with respect to the mixing chamber when the inlet passage is closed with respect to the mixing chamber by the spool. In a mixing head of a reaction injection molding machine in which a bypass passage is connected to which the stock solution supplied to the inlet passage is guided to the outside of the mixing head main body, a flow line is provided from the upstream side of the part of the inlet passage to which the bypass passage is connected to the throttle valve. An extending cylindrical body is provided in the inlet passage.

[Operation] In the present invention, when the inlet passages are closed by the spool, the stock solution supplied to each inlet passage flows from the mixing head main body to the stock solution tank through the bypass passage. At this time, part or all of the stock solution supplied to the inlet passage is guided by the cylindrical body, flows into the inlet passage, flows out toward the throttle valve at an increased speed, and then flows to the upstream side of the inlet passage. and flows into the bypass passage.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

As shown in these figures, the mixing head body 11
A spool insertion hole 12 is passed through the spool insertion hole 12, and the tip side of this spool insertion hole 12 is a mixing chamber 13, and the tip of this mixing chamber 13 is an outlet 14 to a mold (not shown). In addition, the mixing head main body 11
A plurality of inlet passages 15 communicating with the mixing chamber 13 from the outside are formed in the mixing chamber 1.
The same number of return passages 16 as the inlet passages 15 are formed which communicate with the outside from the spool insertion hole 12 on the proximal end side of the spool. The inlet passage 15 is reduced in diameter at a position facing the mixing chamber 13 to form an injection passage 15a, and a throttle valve 17 is provided on the upstream side of this injection passage 15a.

The throttle valve 17 is provided with a throttle opening 17a whose area can be fixed or variable, and applies fluid resistance to the stock solution sent to the inlet passage 15 to bring the stock solution upstream of the throttle valve 17 under high pressure. This allows the stock solution to be jetted out into the mixing chamber 13 at high speed.

Furthermore, a bypass passage 18 is formed in the mixing head main body 11, which is in the middle of the inlet passage 15 and communicates from the upstream side of the throttle valve 17 to the spool insertion hole 12 on the distal side of the return passage 16. . The inlet passage 15 includes the inlet 15.
A nozzle (cylindrical body) 19 is provided that extends from the inlet 15b of the throttle valve 17 toward the throttle valve 17a.

The nozzle 19 is formed into a conical cylindrical shape, and its axis is aligned with the inlet passage and the aperture 17a, and the outer peripheral surface of the enlarged end on one end is closely connected to the inlet passage 15b. The other end, which has a reduced diameter, extends near the aperture 17a.

Further, a spool 20 is inserted into the spool insertion hole 12 and is driven to move in the axial direction by an actuator (not shown).

The spool 20 has its tip end 21 connected to the mixing chamber 13.
The spool 20 is inserted into the spool insertion hole 12 so as to face the spool 20, and when the spool 20 is in the forward position (the position of the spool 20 in FIG. When the spool 20 is in the retracted position (the position of the spool 20 in FIG. 2), the distal end surface 21 is located closer to the proximal end than the injection path 15a. Further, a return passage 1 is provided on the outer peripheral surface of the spool 20 when the spool 20 is moved to the forward position.
6 and the bypass passage 18 and the same number of circulation grooves 22 as the return passages 16 are formed to release the communication between the return passage 16 and the bypass passage 18 when the spool is placed in the retracted position. There is.

In the mixing head configured as described above, when the spool 20 is moved to the forward position, the ejection passage 15a is closed by the outer peripheral surface of the spool 20, and the return passage 1 is closed by the circulation groove 22.
6 and the bypass passage 18 are brought into communication, whereby the stock solutions of different components supplied to each inlet passage 15 are not spouted into the mixing chamber 13, and the bypass passage 18, the circulator 22, and the return passage 16 are connected to each other. to each stock tank. On this occasion,
The stock solution supplied to the inlet passage 15 is guided by the inner peripheral surface of the nozzle 19, flows into the inlet passage 15 at increased speed, and flows out toward the throttle opening 17a of the throttle valve 17. After colliding with the throttle valve 17, the raw liquid flowing out toward the throttle valve 17 flows in the radial direction along the throttle valve 17, further flows along the outer peripheral surface of the nozzle 19 toward the inlet 15b, and then flows into the bypass passage 18.
flows into. Furthermore, when the spool 20 is moved to the retracted position, the distal end surface 21 of the spool 20 is located on the base end side of the ejection passage 15a, and the ejection passage 15a is opened to the mixing chamber 13, and the bypass passage 18 and the return passage 16 is released, and the stock solutions of different components supplied to each inlet passage 15 are jetted into the mixing chamber 13 through the throttle port 17a of the throttle valve 17 and the jet passage 15a, respectively. Then, the stock solution mixed in the mixing chamber 13 flows into a mold (not shown) through the outlet 14.

In the mixing head configured as described above, the stock solution supplied to the inlet passage 15 is passed through the throttle valve 17.
After increasing the speed toward the flow and flowing out, it flows in the radial direction along the throttle valve 17, and further flows toward the inlet 15b along the outer peripheral surface of the nozzle 19, and flows into the bypass passage 1.
8, even if fillers and the like are mixed in the stock solution, the fillers and the like will flow with the high-speed flow of the stock solution and will not be deposited on the throttle valve 17 and the throttle port 17a. Therefore, it is possible to prevent the aperture opening 17a from being clogged by filler or the like.

In the above embodiment, the nozzle 15 is formed into a conical shape, but as shown in FIG. 3, a nozzle 31 having a flange 31a formed on the outer periphery of one end of a cylindrical body may be used, or as shown in FIG. Alternatively, the nozzle 32 formed in a cylindrical shape may be simply fixed to the inlet passage 15 by connecting members 33 arranged at intervals in the circumferential direction. However, it goes without saying that these nozzles are not limited to having a circular cross section, but may have a polygonal cross section.

[Effects of the invention] As explained above, according to the invention, the cylindrical body extending from the upstream side of the part of the inlet passage to which the bypass passage is connected to the throttle valve is provided in the inlet passage. A part or all of the stock solution supplied to the tube can be guided by the cylindrical body and flowed out toward the throttle valve. Therefore, even if a filler or the like is mixed in the stock solution, the filler or the like will not accumulate on the throttle valve, thereby preventing the throttle valve from clogging.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a mixing head shown as an embodiment of the present invention, in which FIG. 1 shows the spool moved to the forward position, and FIG.
The figure shows the spool moved to the retracted position, Figures 3 and 4 are cross-sectional views showing other nozzles, and Figures 5 and 6 are cross-sectional views of a mixing head shown as a conventional example. FIG. 5 is a view showing the spool moved to the forward position, and FIG. 6 is a view showing the spool moved to the retracted position. 11...Mixing head body, 12...Spool insertion hole, 13...Mixing chamber, 15...Inlet passage, 16
...Return passage, 17... Throttle valve, 18... Bypass passage, 19... Nozzle (cylindrical body), 20... Spool, 22... Circulation groove.

Claims (1)

[Claims for Utility Model Registration] A mixing head body in which an inlet passage is formed for individually introducing a plurality of stock solutions into the mixing chamber of a spool insertion hole whose tip side is a mixing chamber, and the inlet passage of the mixing head body. a throttle valve installed in the mixing chamber for spouting the stock solution at high speed; and a spool inserted into the spool insertion hole of the mixing head main body to open and close the inlet passage with respect to the mixing chamber; The upstream side of the throttle valve in the inlet passage is arranged such that when the inlet passage is closed to the mixing chamber by the spool, the stock solution supplied to the inlet passage is directed to the outside of the mixing head body. In the mixing head of a reaction injection molding machine, the inlet passage is provided with a cylindrical body extending from the upstream side of the part to which the bypass passage is connected to the throttle valve. A mixing head for a reaction injection molding machine, characterized in that: