JPH03193239A - Method for cleaning molding sand kneading apparatus - Google Patents

Abstract

PURPOSE:To improve the cleaning effect on a molding sand kneading apparatus by introducing solvent type detergent and rigid balls, working rotary blades to separate the stuck molding sand and discharging the separated molding sand together with the detergent and the rigid balls. CONSTITUTION:At the time of removing the hardened molding sand stuck to inner part of a kneading case, particularly gap part between inner wall part of the kneading case 2 at rear step and rotary blades 6 in the continuous kneading type molding sand kneading apparatus, the rigid balls together with the solvent type detergent are introduced into the apparatus, and by working the rotary blades 6, the stuck molding sand is separated and the separated molding sand is discharged together with the detergent and the rigid balls. By this method, the hardened molding sand can be efficiently removed by the simple method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for cleaning a mold sand kneading device that efficiently removes hardened mold sand adhering to the inside of the mold sand kneading device equipped with rotating blades.

PRIOR TECHNOLOGY Conventionally, patch-type or continuous-type molding sand kneading equipment equipped with rotating blades have been used to prepare molding sand.
Hardened molding sand adheres to the inner wall of the mixing case and the rotating blades over time, which not only reduces the mixing effect, but also causes the rotary blades to wear out due to contact with the hardened molding sand, so regular cleaning is essential. This work is being carried out.

Conventional cleaning methods mainly rely on manual labor such as hammering, which requires a great deal of labor and time, and also significantly reduces the operating rate of the kneading equipment.
Improvement measures are desired.

Problems to be Solved by the Invention The present invention has been made in response to such demands and to provide a cleaning method that can efficiently remove hardened molding sand adhering to the inside of a molding sand mixing device in a simple manner. .

Means for solving the problem, that is, the present invention, introduces a solvent-based cleaning agent and a rigid ball into a flange-shaped sand kneading device equipped with a rotating blade in which hardened molding sand is adhered, and operates the rotating blade to prevent the adhesion. The present invention relates to a method for cleaning a molding sand mixing apparatus, which comprises liberating molding sand and discharging the loose molding sand from within the apparatus along with the cleaning agent and rigid balls.

Hereinafter, the present invention will be explained based on the accompanying drawings.

FIG. 1 is a schematic diagram showing the process of cleaning a continuous kneading type molding sand kneading device according to the present invention.

The molding sand kneading device is arranged inside a former kneading case (1), a latter kneading case (2) connected to a molding sand outlet (lO) of the kneading case (1), and a former kneading case (1). A rotating blade (
5) and a rotating blade (6) rotated by a drive motor (8) disposed inside the rear mixing case (2), and the front mixing case (1) has a molding sand inlet (
9), curing agent inlet (13), and rear kneading case (
2) are each provided with a resin injection port (14).

The molding sand is passed through the molding sand inlet (9) into the pre-mixing case (
1) and is kneaded and transferred by the rotary blade (5) together with the curing agent injected from the curing agent inlet (13), and then passed through the mold sand outlet (lO) to the latter stage kneading case (2).
), where it is kneaded and transferred by a rotating blade (6) together with a resin-based binder injected from a resin injection port (14), and then into a predetermined mold through a molding sand discharge port (11). It is guided and molded into a mold.

In the above-mentioned kneading process, hardened molding sand adheres to the inside of the mixing case, particularly to the gap between the inner wall of the latter-stage kneading case (2) and the rotating blade (6), resulting in the above-mentioned problem.

In the present invention, the rigid ball (15) is introduced together with a solvent-based cleaning agent into the molding sand kneading device equipped with rotating blades in which the hardened molding sand is adhered as described above, and the joint action of the two is used to mold the adhered molding sand. Release and remove sand.

The solvent-based cleaning agent used in the present invention is based on various organic solvents, mixed with appropriate additives such as rust preventives, antistatic agents, surfactants, etc., and is used to reduce the viscosity of molding sand. It may be selected as appropriate depending on the type of binder, curing agent, etc.

Examples of organic solvents include alcohols (e.g., ethanol, isopropyl alcohol, imbutanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, cyclohexanol, etc.), polyhydric alcohols and their derivatives (e.g., butanediol, dienethylene glycol monoethyl ether, etc.). , ethylene glycol monoethyl ether, ethylene glycol butyl ether, etc.), hydrocarbons (e.g., n-hexane, kerosene, toluene,
xylene, isopropylbenzene, tetralin, decalin, cyclohexane, etc.), chlorinated hydrocarbons (e.g.
Methylene chloride, 1,1.1-trichloroethane, trichlorethylene, perchlorethylene, carbon tetrachloride, propylene dichloride, chloroform, 1.1.2-1-
dichloro-1,2,2-trifluoroethane, etc.), ketones (e.g., methyl isobutyl ketone, methyl ethyl ketone, acetonylacetone, diacetone alcohol, isophorone, etc.), nitrogen-containing solvents (e.g., 2-nitropropane, nitrobenzene, triethylamine) , isopropylamine, diethylenetriamine, tetraethylenepentamine, cyclohexylamine, monoethanolamine,
Jetanolamine, triethanolamine, impropaturamine, morpholine, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-
2-pyrrolidone, pentaethylenehexamine, etc.), and esters (e.g., ethyl acetate, ethyl lactate, γ-
(butyrolactone, propylene carbonate, triethyl phosphate, etc.)
etc.

As the rigid sphere, spheres having excellent wear resistance and impact resistance and appropriate hardness and weight, such as spheres made of steel, stainless steel, and ceramic, are preferable. Although the size of the rigid sphere is not particularly limited, if it is too large or too small, it will be difficult to transport it by the rotary vanes (5) and (6). Therefore, suitable rigid spheres include the kneading case (1) and (
It is a spherical body having a diameter that is 1 mm"l011!1 larger than the distance between the inner wall of 2) and the tips of the rotating blades (5) and (6).

The solvent-based cleaning agent and the rigid sphere may be introduced into the molding sand kneading device at the same time, but the former is introduced first to soften or peel off the adhered hardened molding sand, and then the latter is introduced,
While operating the rotary vane to transport the rigid spheres, the softened or exfoliated molding sand is forcibly brought into contact with the rigid spheres, thereby liberating the molding sand and discharging the molding sand (11).
A preferred method is to transport the

The method of cleaning the inside of the molding sand kneading device using a solvent-based cleaning agent may be appropriately selected depending on the type of the kneading device, the type and amount of hardened molding sand, the type of cleaning agent, etc. For example, a method of dispersing the cleaning agent into the kneading device using a spray or the like, or introducing the cleaning agent into the kneading device from the molding sand inlet (9) and operating the rotary vanes (5) and (6) for cleaning. An example of this method is to stir and flow the agent in a mixing device.

In addition, the amount of rigid balls (15) introduced into the kneading device is determined by considering the rotational load of the device, and the amount of rigid balls (15) introduced into the kneading device is determined by considering the rotational load of the device. ) should be adjusted so that it contacts evenly. For example, a hopper (3) loaded with rigid balls (15) is provided in the upper part of the front-stage mixing case (1), and by adjusting a damper (12) disposed at the lower part of the hopper (3), the rigid balls are It is advisable to select the amount of introduction as appropriate.

The rigid balls (15) introduced from the hopper (3) into the pre-mixing case (1) through the molding sand inlet (9) are transferred while entraining the molding sand adhered to them by the rotation of the rotary vane (5), and the molding sand flow The latter kneading case (
2) After being introduced into the molding sand, the molding sand is further transferred while being entrained by the rotation of the rotary vane (6), and is discharged from the molding sand discharge port (11).

If the above cleaning process is insufficient, the hopper (
4) is provided at the bottom of the molding sand discharge port (11) to discharge free molding sand, cleaning agent and rigid balls to the hopper (4),
replace said hopper (4) with an empty hopper (3), or
Alternatively, the cleaning process may be repeated by communicating the hopper (4) via a conveyor (not shown) to return the rigid balls in the hopper (4) to the hopper (3).

In this case, in an embodiment using a conveyor,
By installing the conveyor and hoppers (3) and (4) on a frame equipped with moving wheels, cleaning of a large number of crosstalk devices can be carried out sequentially and efficiently.

In addition, when collecting and temporarily storing the rigid balls used in the above-mentioned cleaning process, the rigid balls collected in the hopper (4) are stored together with molding sand and cleaning agent in a conventional manner, for example. The rigid balls may be put into a batch-type molding sand kneading device, mixed with the waste liquid of the previously used cleaning agent, and then sieved.

Hereinafter, the present invention will be explained by examples.

Example 1 Using a molding sand kneading device shown in FIG. 1, molding sand was kneaded according to the following formulation: Compounding components
Blend amount (parts by weight) Silica sand
100 Binder (furan resin) 0.7 Hardening agent (methaxylene sulfonic acid) 0.35 The hardened molding sand that had adhered to the kneading case and rotating blades by the above kneading operation was cleaned by the following procedure.

A cleaning agent (70% by weight of dimethylacetamide, 2% by weight of alkanolamine and 28% by weight of N-methylpyrrolidone) is introduced into the kneading device through the mold sand inlet (9). Internal volume of the kneading case: approx. 120Q1 kneading case Distance between inner wall and rotary blade tip: 26.5mm)
, by feeding the cleaning agent to the rear crosstalk case (2) while operating the rotary vanes (5) and (6).
The adhering molding sand was softened and peeled off, and the used cleaning agent was discharged outside the system.

Next, a large number of steel spheres (
diameter: 30+1 m) is introduced into the kneading case (1) by adjusting the damper (12), and the rotating blades (5) and (6
), the steel spheres were transferred to the hopper (4) via the latter kneading case (2).

The molding sand that had been softened and peeled off by the cleaning agent was almost completely entrained by the steel spheres moving within the crosstalk device, resulting in a cleaning effect that was incomparable to conventional manual cleaning.

The cleaning process described above was completed in about 30 minutes, whereas the manual cleaning process required about 90 minutes.

Effects of the Invention According to the present invention, hardened molding sand adhering to the inside of a molding sand kneading device can be easily, quickly and effectively removed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the process of cleaning a continuous mixing type molding sand kneading device according to the present invention. (1) is the front-stage kneading case, (2) is the rear-stage mixing case, (
3) and (4) are hoppers, (5) and (6) are rotating blades, and (7) and (8) are drive motors.

Claims (1)

[Claims] 1. Introducing a solvent-based cleaning agent and a rigid ball into a molding sand kneading device equipped with a rotary blade in which hardened molding sand has adhered, and operating the rotary blade to release the adhered molding sand. . A method of cleaning a molding sand mixing apparatus comprising discharging loose molding sand from within the apparatus along with the cleaning agent and rigid balls. 2. The rigid ball is 1 larger than the distance between the kneading case and the rotating blade.
2. The cleaning method according to claim 1, wherein the sphere is made of metal or ceramic and has a larger diameter of mm to 10 mm.