JPH10296830A - Liquid-form substance injection valve for extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excessive resin from entering the space part of an injection valve by a method wherein a needle valve is provided on a piston which is inserted in the cylinder of the valve main body, and on the opposite side of the piston, a coil spring which closes the injection port by the needle valve, is provided, and the pressing force of the coil spring is regulated by a thread which is provided on the cylinder. SOLUTION: One end of a valve main body 11 is screwed with a barrel 12 of an extruder, and the other end is made a cylinder 14 in which a piston 13 is fitted. In the axial center part of the valve main body 11, a passage 18 wherein a liquidized substance is introduced from a flow-in port 15, and the liquidized substance is introduced into the barrel 12 and a cylinder chamber 17 through an injection port 16, is provided. To the piston 13, a needle valve 19 is fixed, and the needle valve 19 is always pressed to the seal surface B of the injection port 16 by a coil spring 20, and at the same time, the piston 13 retracts by the pressure of the liquidized substance which works from the passage 18, and injection port 16 opens, and the liquidized substance is injected into the barrel 12. Also, a cap 22 is screwed with the thread 21 provided on the valve main body 11, and by turning the cap 22, the pressing force of the coil spring 20 is regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid material injection valve for adding and injecting a liquid material such as water, oil, improver and the like to a resin material which is melted, kneaded and discharged in a barrel of an extruder.

[0002]

2. Description of the Related Art Referring to FIG. 2, a conventional liquid injection valve of this type will be described.
The valve body 3 is screwed via a gasket 4 so that resin from inside the barrel 1 does not enter the screwing portion. A passage 6 is provided in the center of the valve body 3 so that the liquid material is injected into the barrel 1 from the outside through the inlet 5 at the tip end as shown by an arrow a. A ball-type check valve 7 is provided near the injection port 5 of the passage 6 so that the resin or liquid from the barrel 1 cannot flow back into the injection valve.

[0003]

Therefore, when the liquid material is injected into the barrel 1, the liquid material flows as indicated by an arrow a.
The check valve 7 is pushed open and injected into the barrel 1,
There is a space between the injection port 5 and the sealing surface A, and when the injection pressure of the liquid at the time of starting or stopping the operation of the extruder is not applied, the resin enters the space from inside the barrel 1,
As a result of not being able to maintain the injection amount of the liquid material, the resin that has entered remains in the space as it is, deteriorates, decomposes and carbonizes, not only is it mixed into the product discharged by the extruder, The check valve 7 does not operate.

An object of the present invention is to prevent the resin from entering the space of the above-described injection valve from the inside of the barrel to maintain the injection amount of the liquid material, or the resin that has entered remains in the space, deteriorating or decomposing. It is an object of the present invention to provide a liquid injection valve in which defects such as mixing in a product discharged by an extruder as a result of carbonization of the liquid are eliminated.

[0005]

According to the present invention, there is provided a liquid material injection valve for injecting a liquid material introduced from outside into an extruder through an injection port. A valve body attached to the barrel with a screw, the other end of which is a cylinder, and a valve body provided with a passage for guiding the liquid material to an inlet at the one end from an inflow port provided in the middle of the shaft center, and a cylinder at the other end. A needle valve that is attached to a movably inserted piston, extends into the passage, and opens and closes the injection port at one end with a liquid material introduced into the cylinder and a coil spring described later; and a counter needle of the cylinder piston A coil spring that is provided on the valve side and constantly presses the needle valve to close the inlet at one end, and is attached to the cylinder at the other end with a screw, and the length of the cylinder is pushed and pulled by the same screw. Varied was liquid material injection valve of the extruder comprised and a pressure adjusting device for adjusting the pressing force of the coil spring.

[0006] Since there is no extra space between the needle valve and the injection port, and no resin enters from inside the barrel, the problem of the injection amount of the liquid material and the problem of the carbide mixed into the product are raised. It was removed and the injection pressure of the liquid could be adjusted.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a liquid material injection valve for injecting a liquid material introduced from the outside into a barrel of an extruder, one end having an injection port is attached to a barrel with a screw, and a liquid material acting on a cylinder at the other end of the cylinder acts with a coil spring. A needle valve attached to a piston slidably fitted by a body was provided, and the needle valve was moved to provide a liquid injection valve of an extruder for opening and closing the injection port at the one end.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.
Reference numeral 10 denotes a liquid material injection valve. One end of a valve body 11 is screwed into a barrel 12 of an extruder, and the other end is a cylinder 14 in which a piston 13 is slidably fitted. A passage 18 is provided at the axial center of the valve body 11 for introducing a liquid from an inlet 15 and introducing the liquid into the barrel 12 and the cylinder chamber 17 through an inlet 16 opened at the one end. The piston 13 extends into the passage 18 and extends through the inlet 1 at one end.
A needle valve 19 that opens and closes the valve 6 with a seal surface B is fixed, and a coil spring 20 provided on the cylinder chamber 17 on the side of the piston 13 opposite the needle valve always presses the needle valve 19 against the seal surface B of the inlet 16. At the same time, the inlet 16 is opened by the liquid pressure acting from the passage 18.

A screw 21 is provided at the other end of the valve body 11, and a cap 22 is screwed thereto.
By rotating, the pressing force of the coil spring 20 can be adjusted. Reference numeral 23 denotes a lock nut of the cap 22. The cap 22 is provided with a bolt 24 for pushing the piston 13 from the outside, so that the moving distance of the needle valve can be adjusted, and the cap 22 can be fixed by a fixing nut 25.

When the liquid material is injected into the barrel 1 as described above, the liquid material first enters the passage 18 from the inflow port 15, but the sealing surface of the injection port 16, which is the outlet port. Since B is closed by the needle valve 19, it stops in the passage 18 as it is. However, when the force generated by the pressure of the liquid material becomes larger than the pressing force of the coil spring 20 pressing the needle valve 19, the piston 1
3 retreats (moves to the left in the figure) against the pressing force of the coil spring 20, the needle valve 19 separates from the sealing surface B,
The liquid material can be injected into the barrel 12.

[0011]

As described above, the sealing surface B to be sealed by the needle valve is located very close to the inlet for injecting the liquid material into the barrel, and there is no extra space for the resin from the barrel to enter.

[Brief description of the drawings]

FIG. 1 is a sectional view of a liquid injection valve showing one embodiment of the present invention.

FIG. 2 is an explanatory view of a conventional ball check valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Liquid injection valve 11 Valve main body 12 Barrel 13 Piston 14 Cylinder 15 Inlet 16 Injection 17 Cylinder chamber 18 Passage 19 Needle valve 20 Coil spring 21 Screw 22 Lock nut 23 Cap 24 Bolt 25 Fixing nut

Claims (1)

[Claims] 1. A liquid material injection valve for injecting a liquid material introduced from the outside into an extruder through an injection port, one end having an injection port is attached to a barrel of the extruder by a screw, the other end is a cylinder, and a shaft is provided. A valve body provided with a passage for guiding the liquid material to an inlet at the one end from an inlet provided in the center of the core,
A needle valve attached to a piston slidably fitted in the cylinder at the other end, extending into the passage, and opening and closing the inlet at the one end with a liquid material introduced into the cylinder and a coil spring described later; A coil spring that is provided on the side of the piston opposite to the needle valve and that constantly presses the needle valve to close the injection port at one end, and is attached to the cylinder at the other end with a screw, and the cylinder is pushed and pulled by the same screw. A liquid injection valve for an extruder, comprising: a pressure adjusting device that adjusts a pressing force of a coil spring by changing a length.