JPH034020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a mixing head for multi-component liquid plastic raw materials, and relates to an improvement in the sealing structure within the mixing head when circulating each raw material liquid.

<Prior Art> Conventionally, there have been mixing heads of this type, such as those shown in FIGS. 12 to 14 for urethane reaction injection molding (see Japanese Patent Publication No. 35101/1983, etc.). FIG. 12 shows a longitudinal section of the mixing head when the rod-shaped valve body 2 is located at the front dead center. In communication with the A liquid ejection hole/return hole 4, 5 and the B liquid ejection hole/
Return holes 6 and 7 are formed. Naturally, the axes of the A liquid jetting hole 4 and the B liquid jetting hole 6 are aligned. A rod-shaped valve body 2 having circulation grooves 10 and 11 is fitted into the through hole 3 so as to be movable in the axial direction. When the rod-shaped valve body 2 is located at the front dead center, each raw material liquid is passed between the raw material tanks and each raw material tank by a pump (not shown), from the raw material tank to the spout hole 4 to the circulation groove 10 to the return hole 5 to the raw material tank. Or raw material tank → spout 6 →
It circulates like the circulation groove 10→return hole 7→raw material tank.

Fig. 13 shows a cross section of the mixing head (with only the head block 1 cut away) when the rod-shaped valve body 2 is located at the after-dead center. When the grooves 10 and 11 are closed, the raw material liquids are ejected at high pressure from the ejection holes 4 and 6, collide and mix just before the tip surface of the rod-shaped valve body 2, and are injected axially forward of the rod-shaped valve body 2.

In the above mixing head, the circumferential surface of the rod-shaped valve body 2 has circulation grooves 10, 11 as shown in FIGS. 13 and 14.
Three axial seal longitudinal grooves 8 extending over the entire length of the rod-shaped valve body 2 are formed at positions between the two. Also,
A circumferential seal lateral groove 9 is provided at the front and rear ends of the rod-shaped valve body 2.
Two rows are formed each. When liquids A and B enter the seal vertical groove 8 and mix in contact, a urethane seal is formed, and liquids A and B enter the seal vertical groove 8, forming a urethane seal.
Further contact of liquid B is prevented. Similarly, a urethane seal is formed in the seal lateral groove 9, and A
This will prevent liquid and B liquid from leaking in the axial direction of the rod-shaped valve body 2.

<Problems to be Solved by the Invention> However, the above mixing head had the following problems.

(a) In the vertical seal grooves 8 and the horizontal seal grooves 9, liquids A and B cannot be reacted and solidified at an ideal mixing ratio, so the physical properties of the urethane seal are not uniform, resulting in variations in sealing performance. Furthermore, if hard urethane is produced, sealing properties cannot be achieved. Also, the urethane seal is A
The liquid and B liquid gradually flow into the vertical seal groove 8 and the horizontal seal groove 9 to form a multilayered structure in which they react and solidify, so the surface layer (which acts as a seal) tends to peel off when sliding against the inner wall of the through hole 3. . In other words,
Perfect sealing performance cannot be expected from these urethane seals, so the dimensional accuracy of the rod-shaped valve body 2 and the through hole 3 must be increased to minimize leakage of liquids A and B. Therefore, the processing of the mixing head,
The assembly costs are high, and the rod-shaped valve body 2 and the inner wall of the through hole 3 are abraded, making it impossible to expect high durability.

(b) This is fine if liquids A and B are reactive, but when mixing unreactive raw material liquids (for example, oil and oil additives), the seal vertical grooves 8 and the seal horizontal grooves 9 are self-contained. Cannot perform sealing action.

The above problems (a) and (b) need to be prevented especially in the circumferential direction of the rod-shaped valve body. This is because if other raw material liquids enter the circulation groove, there is a risk that "clogging" will occur in the raw material liquid circulation channel.

<Means for Solving the Problems> The present invention has been made to solve the above problems, and the head body is provided with a through hole, and the side walls of the through hole are provided with circumferential positions relative to each other. A plurality of spout ports for different raw material liquids are provided which open at different times, and a rod-shaped valve body is fitted into the through hole so as to be able to reciprocate, and when the rod-shaped valve body is located at the front dead center,
Each raw material liquid is circulated between each raw material tank,
In the mixing head configured such that when the rod-shaped valve element is located at the rear dead center, the raw material liquids are collided and mixed and are injected in the front axial direction of the rod-shaped valve element, the rod-shaped valve element is in an axial position. It has a first seal part and a second seal part that slide on the side wall of the through hole, and the first seal part and the second seal part are arranged in the axial direction when the rod-shaped valve body is located at the front dead center. from the first seal portion to the second seal, which are located on both sides of the spout and are in sliding contact with a circumferential position on the outer circumferential surface of the rod-shaped valve body and at an intermediate position between the jet ports that are adjacent to each other in the circumferential direction; A sealing member extending along the axial direction extending to the through hole is embedded, and/or the rod-shaped valve body is located at a circumferential position on the inner wall of the through hole, and at an intermediate position between the jet ports adjacent to each other in the circumferential direction. A mixture characterized in that a sealing member is embedded along the axial direction from a position in the axial direction where it abuts the first seal part to a position in the axial direction where it abuts the second seal part when the mixture is located at the dead center. It's a head.

<Example> Hereinafter, the present invention will be explained in detail by taking a mixing head for reaction injection molding of urethane as an example.

FIG. 1 is a half-sectional view of the mixing head 21 of this embodiment, and FIG. 2 is a schematic perspective view showing the circulation flow path for liquid A (polyisocyanate component) and liquid B (polyol component).

The head body 23 of the mixing head 21 of the embodiment has a through hole 2 located on the extension line of the sprue of the mold.
5 is bored, and a rod-shaped valve body 51 is inserted into this through hole 25.
(see Fig. 5) is fitted so as to be slidable in the axial direction. As shown in FIG. 2, a liquid inlet 27 for liquid A is formed on one side of the head body 23.
A circulation channel 29 for liquid A is formed above the through hole 25 . Similarly, the through hole 2 is connected to the B liquid inlet 31 formed on the other side of the head body 23.
A circulation flow path 33 for the B liquid is formed below the B liquid. Each circulation flow path 29, 33 has a jet port 28, 32 facing the through hole 25 in the front cylindrical portion 24 of the head body 23. Of course, these spouts 2
The axes of 8 and 32 coincide. Each of the circulation channels 29 and 33 rises upward on the same plane at the rear portion of the head body 23, for example, and is once separated by the plunger insertion hole 35. reach.

In the plunger insertion hole 35, as shown in FIG.
The switching plunger 41 is inserted into the plunger insertion hole 3
5 so as to be movable in the axial direction. It is desirable that the switching plunger 41 is controlled by the same hydraulic system as the rod-shaped valve body 51, and that the movements of both are synchronized. The switching plunger 41 has large diameter portions 43, 44 and small diameter portions 45, 46, each having the same diameter as the plunger insertion hole 35, corresponding to each circulation flow path 29, 33. The small diameter portions 45 and 46
As shown in the figure, they simultaneously face the cuts 30 and 34 of the circulation passages 29 and 33 separated by the plunger insertion hole 35, and allow liquids A and B to simultaneously flow from bottom to top as shown in FIG. Note that FIG. 4 is a partial cross-sectional view shown along the - arrow line in FIG. The A liquid will flow through the annular gap 47. Similarly, the B liquid flows through the annular gap 48. On the other hand, when the switching plunger 41 moves to the left in FIG.
3, and the annular gaps 47, 48 are simultaneously closed. Therefore, by reciprocating the single switching plunger 41, the circulation channels 29 and 33 for liquid A and liquid B are simultaneously opened and closed.

Next, the rod-shaped valve body 51 that is inserted into the through hole 25 of the head body 23 will be explained.

FIG. 5 shows a side view of the rod-shaped valve body 51, and the rod-shaped valve body 51 of the embodiment has a rod portion 53 and a first seal portion 5.
5, a shield valve part 57, a second seal part 59, and a throttle valve 65, and a flange part 62 attached to a piston 77 of an actuating device 75 is provided at the rear end (see FIG. 1). An oval keyway 54 is bored in the middle of the rod portion 53. Further, seal grooves 56 and 58 are formed in the circumferential direction in the first seal part 55 and the second seal part 59, respectively, and when liquids A and B flow into these grooves 56 and 58, they react and form a urethane seal. form and exhibit a self-sealing effect. Of course, a seal ring may be attached to each seal groove 56, 58.

A horizontally long portion formed from the second seal portion 59 to the shield valve portion 57 and the first seal portion 55 indicates the circumferential surface of the seal member 61. The sealing member 61 is a plate-like member made of fluororesin and having a substantially trapezoidal cross section with an arcuate upper side, and as shown in FIG. It is embedded in two dovetail grooves 63 formed in the portion. This sealing member 61 is used when the shielding valve portion 57 shields the jet ports 28 and 32 (the state shown in FIG. 1).
By bringing the outer peripheral surface into close contact with the peripheral wall of the through hole 25,
The liquid and B liquid are prevented from leaking in the circumferential direction of the shielding valve portion 57.

A throttle valve portion 65 formed at the tip of the rod-shaped valve body 51
As shown in FIG. 7, protruding pieces 67 and 69 having an arcuate cross section are formed on the upper and lower sides, and are formed separately from the other parts constituting the rod-shaped valve body 51, and are secured in the circumferential direction by screws or the like. Rotatably fixed.

When the piston 77 of the actuating device 75 is moved to the left in the figure from the state of FIG. 1 in which the rod-shaped valve body 51 is at the front dead center, and the rod-shaped valve body 51 is positioned at the rear dead center (see FIG. 8), The throttle valve part 65 that protrudes from the head body 23 to the outside is connected to each circulation flow path 2 for liquid A and liquid B.
9 and 33, facing the jet ports 28 and 32. At this time, Fig. 9 (showing a cross section along the - arrow line in Fig. 8)
As shown in the figure, the upper protruding piece 67 shields the spout 28 by a predetermined amount, and similarly the lower protruding piece 69 shields the spout 32 by a predetermined amount. 9, when the throttle valve section 65 is rotated left and right, the spout ports 28, 32
The opening amount can be adjusted steplessly, and the protruding piece 6
7, 69 are formed symmetrically, the opening amount of each jet port 28, 32 is increased or decreased in proportion.

Note that FIG. 10 shows a sectional view of the same portion as FIG. 9 when the rod-shaped valve body 51 is at the front dead center (cross-sectional view taken along the - arrow line in FIG. 1). Each circulation channel 29,
The openings 28 and 32 of 30 are completely shielded by a shield valve section 57.

Next, the operation of the mixing head 21 will be explained.

First, the rod-shaped valve body 51 is positioned at the front dead center as shown in FIG. 1, and the switching plunger 4 is positioned as shown in FIG.
The small diameter portions 45, 46 of 1 are opposed to the cuts 30, 34 of the circulation paths 29, 30. And liquid A, B
A pump (not shown) is operated to transfer the liquid to each raw material tank (not shown) through the liquid inlet 27 →
The liquid is circulated for a predetermined period of time via the circulation flow path 29 → annular gap 47 → liquid outlet 37 or liquid inlet 31 → circulation flow path 33 → annular gap 48 → liquid outlet 39.

Next, as shown in FIG. 8, the rod-shaped valve body 51 is positioned at the rear dead center, and the switching plunger 41 as shown in FIG.
to the left and cut the large diameter parts 43, 44 into the cuts 30,
34 and simultaneously shield each circulation flow path 29, 33. And A pressurized to high pressure in the above
The liquid and B liquid are ejected at high pressure from the respective ejection ports 28 and 32 as shown in FIG. 9, collide and mix in the throttle valve part 65,
It will be injected axially forward of the rod-shaped valve body 51.

After that, when the rod-shaped valve body 51 is again positioned at the front dead center (the state shown in FIG. 1), the throttle valve part 65 will be in a state of protruding from the front cylindrical part 41 of the head body 23, so it can be cleaned as necessary. becomes possible.

In addition, in the mixing head 21, the ejection ports for each raw material liquid may be formed at deeper positions than the through holes 25, and in that case, the rod-shaped valve body 51 is correspondingly shortened, so that when it is at the front dead center, However, the throttle valve portion 65 no longer protrudes from the head body 23.

In addition, when mixing three or more types of raw material liquids,
A liquid inlet, circulation flow path, jet port, and liquid outlet are formed according to the number of raw material liquids. At this time, each jet port is designed so that its axis intersects approximately at the center of the through hole 25, and a cylinder fitting hole is formed so as to linearly penetrate each circulation flow path. Further, an axial sealing member is embedded in the circumferential surface of the shielding valve portion of the rod-shaped valve body so as to divide each jet port.

In the mixing head 21 described above, the feature of this embodiment is that two fluorine strips are provided in the axial direction on the circumferential surface of the shielding valve portion 57 of the rod-shaped valve body 2 at intermediate positions between the respective jet ports 28 and 32. Resin seal member 61
is buried therein, and the sealing member 61 is in close contact with the inner wall of the through hole 25 to actively prevent leakage of liquids A and B.

In the above, the seal member 61 is
It may be similarly buried in the inner wall side of the through hole 3 corresponding to. Furthermore, it may be buried in the inner wall of the shield valve part 57 and the through hole, and of course, each of the jet ports 28, 32
The number of embedded strips of the seal member 61 is not particularly limited as long as the seal members 61 are separated from each other. The groove in which the sealing member 61, which is a plate-like member, is embedded also corresponds to the dovetail groove 63.
Although not limited to this, it is desirable that the seal member 61 be undercut in the radial direction so that it does not peel off.

Furthermore, in the above, the material of the sealing member 61 is not limited to fluororesin, but may be made of other synthetic resins such as polyacetal, soft metals, etc. as long as it is softer than the inner wall of the through hole 25 or the rod-shaped valve body 25. Examples include ceramics and the like. If it wears out due to sliding on the inner wall of the through hole or the rod-shaped valve body, it should be replaced.

Of course, a seal member 61 having the same cross-sectional shape may be embedded in each seal groove 8 in the conventional rod-shaped valve body (see FIG. 11 (showing the same cross-section as FIG. 14)).

<Effects of the Invention> As explained above, the mixing head of the present invention has the following effects:
The rod-shaped valve body has a first seal portion and a second seal portion that are in sliding contact with the side wall of the through hole in the axial direction, and the first seal portion and the second seal portion are arranged when the rod-shaped valve body is located at front dead center. It is located on both sides of each jet port in the axial direction, and is in sliding contact with a circumferential position on the outer peripheral surface of the rod-shaped valve body, at an intermediate position between each jet port adjacent to each other in the circumferential direction. A sealing member extending along the axial direction from the first sealing part to the second sealing part is buried and/or at a circumferential position on the inner wall of the through hole, and at a position intermediate between the jet ports adjacent to each other in the circumferential direction. , when the rod-shaped valve body is located at the front dead center, a seal member is embedded along the axial direction from the axial position where it contacts the first seal part to the axial position where it contacts the second seal part. Because of the unique mixing head, leakage of each raw material liquid to the rod-shaped valve body in the circumferential direction is completely sealed. Of course, no problem will occur even if each raw material liquid is unreactive. Therefore, even if the dimensional accuracy of the rod-shaped valve body and through-hole in the mixing head is not very high, "clogging" hardly occurs, reducing maintenance time and reducing processing and assembly costs of the mixing head. It is possible to reduce Furthermore, since the sealing member can be replaced, complete sealing performance can be maintained even if the rod-shaped valve body or the inner wall of the through hole are worn to some extent, thereby improving the durability of the mixing head.

[Brief explanation of drawings]

The figure shows the configuration of a mixing head, and FIG. 1 shows a rod-shaped valve body 51 in a mixing head according to a first embodiment of the present invention.
A half-sectional view showing the state where is at front dead center, Figure 2 is A
A schematic perspective view showing the circulation flow path of liquid and B liquid, FIG. 3 is a sectional view taken along the arrow line in FIG. 1 showing the switching plunger 41, and FIG. 5 is a side view of the rod-shaped valve body 51, FIG. 6 is a cross-sectional view along the - arrow line in FIG. 5, FIG. 7 is a perspective view showing the throttle wall 65, and FIG. A half-sectional view of the mixing head 21 showing the state at the rear dead center, FIG. 9 is a sectional view taken along the arrow line in FIG. 8 showing the jet ports 71 and 73, and FIG. , FIG. 11 is a sectional view showing a state in which a seal member 61 is implanted in the vertical seal groove 8 of the rod-shaped valve body 2 of a conventional mixing head, and FIG. 12 is a sectional view of a conventional mixing head. , FIG. 13 is a cross-sectional view showing the vertical seal grooves 8 and horizontal seal grooves 9 similarly formed on the circumferential surface of the rod-shaped valve body 2, and FIG. 14 is a cross-sectional view along the - arrow line in FIG. 12. 21...Mixing head, 23...Head body, 2
5... Through hole, 28... Spout port, 32... Spout port, 51... Rod-shaped valve body, 55... First seal portion,
59...Second seal portion, 61...Seal member.

Claims (1)

[Scope of Claims] 1. A through hole is formed in the head main body, and a plurality of spout ports for different raw material liquids are provided on the side wall of the through hole at positions shifted from each other in the circumferential direction. When the rod-shaped valve body is inserted so as to be able to reciprocate and the rod-shaped valve body is located at front dead center,
Each raw material liquid is circulated between each raw material tank,
In the mixing head configured such that when the rod-shaped valve element is located at the rear dead center, the raw material liquids are collided and mixed and are injected in the front axial direction of the rod-shaped valve element, the rod-shaped valve element is in an axial position. It has a first sealing part and a second sealing part that are in sliding contact with the side wall of the through hole, and the first sealing part and the second sealing part are arranged in the axial direction when the rod-shaped valve body is located at the front dead center. The first seal part to the second seal part are located on both sides of the outlet and are in sliding contact with a circumferential position on the outer circumferential surface of the rod-shaped valve body at an intermediate position between the respective jet ports adjacent to each other in the circumferential direction. A sealing member extending along the axial direction is embedded, and/or the rod-shaped valve body is located at a circumferential position on the inner wall of the through hole, and at an intermediate position between the jet ports adjacent to each other in the circumferential direction. A mixing head characterized in that a sealing member is embedded along the axial direction from a position in the axial direction where the mixing head contacts the first sealing part to a position in the axial direction where the mixing head contacts the second sealing part when the mixing head is located at a point. .