JPH0631754A - Supply method and its device of liquid matter to casting machine - Google Patents

Abstract

PURPOSE:To enable molding of a cast article which is unnecessary to suspend operation of a casting machine at the time of changeover of a tank, capable of performing operation of the casting machine extending over a long time, can improve production efficiency, moreover, is free from mixing of a bubble and has an excellent quality. CONSTITUTION:The bottom of a an anuxiliary tank 6 and the bottom of a main tank 5 are joined to each other by a supply pipe 11 provided with an automatic opening and closing valve 12 and the bottom of the main tank 5 and a mixer 3 are joined to each other by a liquid supply pipe 13 provided with a supply pipe 15. A decompression pipe and pressurizing pipe provided with the opening and closing valve are joined respectively to the top part of the main tank and that of the auxiliary tank and level sensors LS-1-3 and pressure sensors PI-1'2 are mounted on the main tank and auxiliary tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for preventing a mixture of air and continuously supplying a liquid material such as a liquid urethane resin to a casting machine.

[0002]

2. Description of the Related Art As is well known, for example, a cleaning blade for an electrophotographic copying machine is used in a copying machine, a printer or the like to remove excess toner adhering to a photosensitive drum after transfer. Is manufactured by a casting machine using urethane resin as a raw material. Particularly in the case of urethane resin, a liquid material as a main agent and a liquid material as a curing agent are mixed by a mixer.
After mixing and stirring at a temperature of 0 to 100 ° C., the mixed liquid is discharged into a predetermined mold to mold the cleaning blade and the like.

By the way, in the case of continuously operating the casting machine, as shown in FIG. 2, at least two tanks are prepared for liquid materials of different kinds to be mixed, and the liquid materials from the tanks 21 and 22 are prepared. The supply pipes 23 and 24 are connected to a common supply pipe 26 via a switching valve 25. Then, while the liquid material is supplied from the one tank 21 to the mixer 28 by the pump 27 and the casting machine is operated, bubbles mixed or dissolved in the liquid material in the other tank 22 are stored in the tank 22. After depressurizing and defoaming, the liquid is kept at a predetermined temperature, and when the liquid in one tank 21 is exhausted, the switching valve 25 is switched to transfer the liquid in the other tank 22 to the mixer 28. The supply method is adopted.

[0004]

However, in the above-mentioned conventional supply method, when the tanks 21 and 22 for supplying the liquid material to the mixer 28 are switched by the switching valve 25, the operation of the pump 27 is stopped to stop the liquid supply. It is necessary to interrupt the supply of goods. This is because when the switching valve 25 is switched while the pump 27 is operating, the switching valve 25 and the pump 2
This is because the inside of the pipe 26 between the pipe 7 and 7 becomes negative pressure, and air may be sucked from the joint portion of the pipe 26 and the bubbles may be mixed into the liquid substance.

Therefore, at least while the pump 26 is stopped, the casting machine must be stopped.
It is not desirable to stop the operation of the casting machine even for a short time for the following reasons. That is, the production efficiency is reduced. Once the operation of the casting machine is stopped, it is necessary to wash the inside of the mixing chamber to remove the residual raw material, which requires extra work. When the mixing chamber is washed, when the operation is restarted, each liquid component becomes full, and until the air in the liquid discharged from the casting machine runs out, a material loss called initial flow loss ( Normally, the mixing chamber capacity is 10-30
Times) and loss of time, resulting in a decrease in material yield and a decrease in line operation rate. When the mixing chamber is washed, foreign substances generated by the reaction mixture solidifying around the mixin rotor and the discharge port may remain.Therefore, the discharge pressure may be exceeded or foreign substances may be mixed into the discharge liquid. It may cause a defect.

The present invention has been made in view of the above-mentioned points, and it is not necessary to stop the operation of the casting machine at the time of switching the tank, and the casting machine can be continuously operated for a long time, thereby improving the production efficiency. Can be improved, and there are no bubbles mixed in,
An object of the present invention is to provide a method and apparatus for supplying a liquid material to a casting machine, which is capable of molding a casting product of excellent quality.

[0007]

In order to achieve the above-mentioned object, a liquid material supply method of the present invention has a bottom portion of a liquid material defoaming / heat retaining auxiliary tank near the bottom portion of a liquid material warming main tank. A method of continuously supplying a liquid substance from the main tank to the casting machine by connecting a pipe from the vicinity, and controlling the pressure in the main tank to a predetermined pressure value while controlling the liquid substance of the casting machine. When the amount of liquid in the auxiliary tank is higher than the pressure in the main tank, the liquid is supplied to the mixing chamber and when the amount of liquid becomes less than a predetermined amount, the liquid is continuously supplied to the mixing chamber. , It is to replenish the liquid material of the auxiliary tank to the main tank.

Further, in the liquid material supplying apparatus of the present invention for carrying out the above method, the vicinity of the bottom of the main tank and the vicinity of the bottom of the auxiliary tank are connected by a supply pipe having an opening / closing valve, and The vicinity of the bottom of the tank and the discharge nozzle of the casting machine are connected by a liquid feed pipe of the liquid, and the main tank and the upper end of the auxiliary tank are connected to a decompression pipe and a pressurizing pipe with an opening / closing valve, respectively. A liquid amount detector and a pressure detector are provided in the main tank and the auxiliary tank.

[0009]

According to the liquid material supply method of the present invention having the above-described structure, the liquid material is supplied to the mixing chamber of the casting machine while controlling the pressure in the main tank to a predetermined value. It is unlikely that a change in the amount or a defective blending ratio based on this change will occur. In addition, the pipes between the main tank and the auxiliary tank, and between the main tank and the discharge nozzle of the mixing chamber are connected near the bottom of the main tank and the auxiliary tank, respectively. Since it is provided at the position, it is possible to prevent air from being mixed in at the time of sending the liquid, and it is not necessary to degas the liquid material on the main tank side. Furthermore, the pressure in the auxiliary tank (pressure of nitrogen gas in the nitrogen purge tank)
Since the liquid material is replenished from the auxiliary tank to the main tank in a state where is higher than the main tank, the liquid material does not flow back.

According to the liquid material supplying apparatus of the present invention as defined in claim 2, the above method can be reliably carried out.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for supplying a liquid material to a casting machine according to the present invention will be described below with reference to the drawings showing an embodiment of the apparatus.

FIG. 1 is an overall front view showing an embodiment of a device for supplying a urethane elastomer to a casting machine of a cleaning blade. As shown in the figure, the mold 1 for casting the cleaning blade has an inlet 1a formed in the center of the upper surface along the longitudinal direction thereof. Then, a large number of molds 1 are arranged in a line at a predetermined interval to form a transfer mechanism 2.
It is placed on top and is transported at a constant speed. The mixer 3 is arranged above the casting machine having such a structure, and the discharge nozzle 3a at the lower end of the mixer 3 is arranged.
The urethane elastomer C is intermittently discharged to the mold 1 which is successively conveyed from the mold at a constant speed to mold the cleaning blade.

The urethane elastomer C used for casting in this embodiment is a thermosetting urethane resin liquid prepared by mixing the A-based liquid material as the main component and the B-based liquid material as the curing agent in the mixer 3. . Both the A-based liquid material and the B-based liquid material are supplied using the main tank 5 and the auxiliary tank 6.

Inside the main tank 5, a stirring blade 5a is provided with a motor 5b.
Thus, the stirring blades 6a are arranged in the auxiliary tank 6 so as to rotate by the motor 6b. A pressure reducing pipe 7 having a relief valve 7a interposed therein and a pressurizing pipe 8 having a pressurizing valve 8a interposed therein are connected to the upper end of the main tank 5, and a relief valve 9a is interposed at the upper end of the auxiliary tank 6. Pressure reducing tube 9
And the pressurizing pipe 10 with the pressurizing valve 10a interposed therebetween. Then, one end of each pressurizing pipe 8 and 10 is connected to an inert gas source (not shown) so that an inert gas such as nitrogen gas can be introduced into the tanks 5 and 6. In the main tank 5, the upper limit position level sensor LS-
1, a lower limit position level sensor LS-2 and a pressure sensor PI-1 are installed, and the auxiliary tank 6 has a lower limit position level sensor LS-3 and a pressure sensor PI-2.
Is installed.

The bottom end of the auxiliary tank 6 and the bottom of the main tank 5 (below the lower limit position level sensor LS-2) are connected by a supply pipe 11 having an automatic opening / closing valve 12 interposed therebetween. Further, the bottom end of the main tank 5 and the mixer 3 are connected by a liquid feed pipe 13
Then, the mixer 3 and the bottom of the main tank 5 are connected by a liquid return pipe 14, and a feed pump 15 is provided in the middle of the liquid feed pipe 13.

The main tank 5 and the auxiliary tank 6 are arranged in heat insulation jackets 17 and 18 with heaters 17a and 18a, respectively, and the circumferences of the supply pipe 11, the liquid feed pipe 13 and the liquid return pipe 14 are also respectively. It is covered with a heat insulation jacket 19 with a heater.

Next, with respect to the casting machine having the above construction, the manner of supplying the liquid material will be described.

In FIG. 1, the A-type liquid material and the B-type liquid material are fed from the main tanks 5 and 5 to the mixer 3 by the feed pumps 15 by the liquid feed pipes 13 and respectively by the liquid return pipes 14. Circulate to the main tank 5. During this time, the mixer 3 is continuously operated, and the urethane elastomer is sequentially discharged and flowed into the mold 1 conveyed by the conveying mechanism 2 at a constant speed.

Raw materials are melted and charged into each auxiliary tank 6, and the stirring blades 6 a are rotated and stirred, and the relief valve 9 a is opened to degas the pressure reducing pipe 9 to degas the liquid material. To do.

After the defoaming work is completed, the relief valve 9a
And the stirring blade 6a are stopped and the pressurizing valve 10a is closed.
Is opened and an inert gas (usually nitrogen gas) is introduced into the tank 6, and the temperature is kept at a predetermined temperature by the heat retaining jacket 18.

When the liquid material in the main tank 5 decreases and the lower limit position level sensor LS-2 detects it, the liquid material is supplied from the auxiliary tank 6 to the main tank 5 as follows.

-1 The pressure value in the main tank 5 measured by the pressure sensor PI-1 and the pressure value in the auxiliary tank 6 measured by the pressure sensor PI-2 are compared, and when the pressure value in the auxiliary tank 6 is high, automatic The on-off valve 12 is opened, and the liquid substance in the auxiliary tank 6 is replenished in the main tank 5 through the supply pipe 11.

-2 As the supply of the liquid material into the main tank 5 increases, the pressure in the tank 5 rises, so the relief valve 7a and the pressurizing valve 8a are controlled to open and close so as to be within the set range. The control of each valve is performed by the pressure sensor PI-1.
Is performed based on the pressure value detected by.

-3 When the upper limit position level sensor LS-1 of the main tank 5 detects the full state of the liquid material or the lower limit position level sensor LS-3 of the auxiliary tank 6 detects the reduced state of the liquid material, The on-off valve 12 is closed and the supply is stopped. After that, in the auxiliary tank 6,
The raw material is melted and charged, and the liquid is defoamed while being stirred by the rotation of the stirring blade 6a.

During this period, A from the main tank 5 to the mixer 3
The system and B system liquids are continuously supplied. Therefore, the casting operation is not interrupted.

By the way, in the above embodiment, the automatic on-off valve 1
2. The liquid level sensor LS-1 to 3 and the pressure sensor PI-1.2 are used to automatically open and close the valve 12, but the pressure gauge, the liquid level gauge and the manual on-off valve are used. May be provided, and the operator may open and close the main tank 5 after confirming the pressure and the liquid amount in the main tank 5. Further, although only one auxiliary tank 6 is provided, a plurality of auxiliary tanks 6 may be provided. Further, although the present invention is applied to both the A-based liquid material and the B-based liquid material, it goes without saying that the invention can be applied to only one of them.

[0027]

As is apparent from the above description,
The liquid material supply method and apparatus of the present invention have the following effects.

(1) Unlike the conventional liquid material supply method in which the main tank cannot be replenished without stopping the supply of the liquid material to the casting machine, the liquid material from the main tank to the casting machine is Since the main tank can be replenished while continuing the supply, the casting machine can be operated continuously for a long time, improving the production efficiency and eliminating the work of cleaning the mixing chamber to remove residual raw materials. In addition, it does not cause material loss and time loss called initial flow loss due to restart of operation after cleaning, material yield drop, line operation rate drop, etc., and also discharge pressure over and foreign matter mixed in discharge liquid. It does not cause a line stop or a line defect due to such reasons.

Furthermore, when replenishing the liquid material from the auxiliary tank to the main tank, bubbles are not mixed in the liquid material,
The structure of the main tank is simplified because the auxiliary tank only needs to degas the liquid material and the main tank has only to supply the liquid material. Moreover, since air bubbles are prevented from being mixed into the liquid material, it is possible to mold a cast product of excellent quality and improve the yield.

(2) According to the apparatus of the second aspect, the liquid material supply method of the present invention can be reliably implemented. In particular, as in the above embodiment, if a level sensor for the liquid material and a pressure sensor for the main tank are provided and the liquid material is automatically supplied to the main tank, the burden on the operator can be reduced and the production efficiency can be further improved. Can be improved.

[Brief description of drawings]

FIG. 1 is an overall front view showing an embodiment of a liquid material supply device according to the present invention.

FIG. 2 is an overall front view showing a conventional two-tank type liquid material supply device.

[Explanation of symbols]

 3 Mixer 3a Discharge nozzle 5 Main tank 6 Auxiliary tank 7.9 Decompression pipe 7a / 9a Relief valve 8/10 Pressurizing pipe 8a / 10a Pressurizing valve 11 Supply pipe 12 Automatic opening / closing valve 13 Liquid feed pipe 14 Liquid return pipe 15 Feed pump LS-1 to 3 level sensor PI-1.2 pressure sensor

Claims (2)

[Claims] 1. Near the bottom of the main tank for keeping liquids warm,
A method for continuously supplying liquid material from the main tank to the casting machine by connecting a pipe from the bottom of the auxiliary tank for defoaming and keeping heat of the liquid material. While controlling the value to supply the liquid material to the mixing chamber of the casting machine, and when the liquid material becomes less than the predetermined amount, while continuing to supply the liquid material to the mixing chamber, Is a method for supplying a liquid material to a casting machine, characterized in that the liquid material in the auxiliary tank is replenished to the main tank while the pressure value in the auxiliary tank is increased. 2. The main tank bottom part and the auxiliary tank bottom part are connected by a supply pipe having an opening / closing valve, and the main tank bottom part and the casting machine discharge nozzle are connected by a liquid material. Connected by a feed pipe, to the upper end of the main tank and the auxiliary tank, respectively connected to a pressure reducing pipe and a pressurizing pipe through an open / close valve, and to the main tank and the auxiliary tank, a liquid amount detector and a pressure detector. An apparatus for supplying a liquid material to a casting machine for carrying out the method according to claim 1, which is provided.