JPS6128366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixing tank for mixing liquids and particulate solids. More specifically, it refers to liquids or natural or synthetic resins (hereinafter referred to as resins) that have been liquefied by heating and melting, and fine particles that are blended with the purpose of supplementing, strengthening, or increasing the electrical, mechanical, or other properties of the resins. The present invention relates to a mixing tank equipped with a stirring device for mixing filler materials in the form of solid or particulate materials.

The method of mixing resin and filler using a mixing tank has been used for a long time by material manufacturers and plastic processing manufacturers that handle resin, and is still the mainstream mixing method today. In recent years, non-drive mixers (also called motionless mixers or static mixers) of the screw drive system have begun to be applied to mixing resin compositions, but these mixing devices are limited in the viscosity range of the mixture, Because a homogeneous mixture cannot be obtained depending on the distribution ratio of each component, although it exhibits high efficiency or power saving in some respects, its application is limited. On the other hand, so-called mixing tanks, which mix each composition by rotating stirring blades, allow the applicable viscosity range to be almost freely selected.
It also has the advantage that there are no restrictions on the blending ratio of each composition, and that the structure is simpler and cheaper than other drive systems.Also, it is suitable for mixtures that do not contain curing agents or catalysts that harden the resin. , even when these are combined, a large amount of the mixture can be stored for a long time under specified conditions,
It is also effective as a so-called implant-type raw material tank. Furthermore, it has many advantages, such as the fact that it is easy to add a device for removing air that is likely to be drawn in during mixing, reaction gas, etc. generated.

However, this mixing tank also has drawbacks. FIG. 1 is a schematic cross-sectional view of a very common mixing tank that has been used in the past. A mixture 2 in a mixing tank 1 is stirred by a stirring device 3 that is connected to a drive source such as an electric or air motor (not shown) and rotates. When the mixture 2 is required, it is passed through the flow pipe 5 for the mixture 2 extending from the take-out hole 4 provided at the bottom of the mixing tank 1.
The mixture 2 is discharged from the discharge port (nozzle) 7 by opening the valve 6 that opens and closes the flow path. In this case, even when stirring is stopped or even when stirring is continued, if the mixing tank 1 is filled with the mixture 2 for a long period of time, the discharge capacity may change or it may become impossible to discharge. There are various possible causes for this, such as exceeding the pot life in the case of resin mixtures, but the most common cause is sedimentation of the filler in the mixture → deposition on the bottom → solidification of the deposits. This is a bridging phenomenon. The rate and extent of this occurrence vary depending on the viscosity of the liquid such as resin, the type and amount of filler, etc., but in particular
This phenomenon tends to occur when the resin viscosity is around or below poise. In addition, deposit 8 tends to become a gel-like substance that exhibits non-Newtonian flow when external stress is applied, as is the case with the flow of suspensions (suspensions of solid fine particles) referred to in rheology. In particular, when the mixture 2 is forcibly discharged by external pressure, the flow path is likely to be blocked. Naturally, the amount of settling and then depositing of the filler also depends on the ability of the stirring device 3. However, in most cases there is a blind spot where stirring is not possible,
This occurs more or less during long-term use. Since the deposits 8 also affect the operation of the valve 6, it naturally requires frequent periodic inspection and removal cleaning, but this leads to the stoppage of the line that requires a mixing tank, which reduces productivity. This results in a decrease in For more automated mixing equipment,
This is often a major disadvantage.

FIG. 2 is a sectional view of another type of conventional mixing tank that improves the problems of the mixing tank shown in FIG. 1 to some extent. The improvement is that the position and type of the flow path opening/closing valve 6' have been changed. The stirring blades 9' associated with the stirring device 3' are provided close to the bottom wall of the mixing tank 1' in order to reduce the amount of deposits accumulating on the bottom of the mixing tank 1'. However, this alone does not have the effect on the filler that settles and accumulates in the flow pipe up to the opening/closing valve position, so when the valve is in the closed state, the valve is It forms a part of the pipe, and apparently eliminates the existence of the flow pipe. This method certainly minimizes settling and accumulation of the filler material, and greatly reduces the amount of cleaning required to remove the deposits. However, the valve 6' moves up and down in the flow pipe, and when the mixture 2' is supplied from the mixing tank 1', especially in the case of a highly viscous mixture, the valve 6' in the center of the flow pipe 5' This has the disadvantage of greatly impeding the flow of the mixture 2' and accelerating wear of the valve 6'. Furthermore, the lower part of the valve 6' becomes a bent part 10' of the flow path pipe 5',
Resin and filler are deposited in this area, which ultimately becomes a cause of hindering the vertical movement of the valve 6'.

The present invention enables smooth and stable supply of the mixture from the mixing tank by eliminating separation and sedimentation of powdery solids mixed in the mixture in the mixing tank, solidification of deposits, and blockage of the flow path. There is almost no need for periodic inspection of the equipment. The aim is to obtain a mixing tank that can stabilize and improve productivity and product quality.

The present invention will be explained below with reference to the drawings.

FIG. 3 is a model sectional view of an example of an improved version of the conventional mixing tank shown in FIG. In this case, a new outlet D for the mixture B is provided in the vertical wall of the conventional mixing tank A, and a flow path pipe E having a valve F for opening and closing the flow path is attached thereto. Further, the channel pipe E is characterized in that it is inclined upward by an angle θ with respect to a horizontal line H that is perpendicular to the vertical wall of the mixing tank A. Further, the outlet D is provided so as to be located at the same level as the upper end of the stirring blade I attached to the stirring device C, or 1 mm to several tens of mm above it. When this mixing tank is used for a long period of time, solid particles settle and accumulate at the bottom of the mixing tank A, forming a deposit J, as described in Fig. 1, but the mixture is not supplied to the newly installed outlet D. Since the fluid flows between the nozzle G and is discharged, the flow path pipe E
occlusion was improved. This is thought to be because the solid particles separated and settled in the flow pipe E fall into the mixing tank A due to the inclination of the flow pipe E and the slight transmission and vibration of the motion of the stirring blade I. Note that the tank lid K in Figure 3 may be omitted depending on the purpose of the mixing tank and the mixture, and the hole L is for reducing or pressurizing the inside of the mixing tank A depending on the purpose. In some cases, it is good even without it.

FIG. 4 is a model cross-sectional view of a mixing tank that is a further improved version of the mixing tank shown in FIG. 3, which is another example of implementation. Bottom wall of mixing tank A′
By providing the stirring blade I' close to M', the amount of sediment that settles and accumulates on the lower side of the mixing tank is minimized, the uniformity of the mixture composition ratio is increased, and the quality is improved. The flow of the mixture B' is achieved by the take-out hole D' provided in the vertical wall of the mixing tank and the slanted flow pipe E' connected thereto, producing the same effect as shown in FIG. In addition, the hole made in the tank lid K′
N' is an input port for the mixture raw material composition, and window O' is for observing the inside of mixing tank A', and is added for purposes such as pressurizing mixture B'.

As described above, according to the present invention, in a mixing tank that stirs a mixture composition and is used for a long period of time, particulate solids such as a filler are separated from a solvent such as a resin → sedimentation → deposition → flow path of the mixture. This improves conventional problems such as pipe blockage, and eliminates the need for regular inspections and cleaning of the mixing tank, which enables the production line to operate continuously for long periods of time, contributing to increased productivity. can. In addition, the impact on the human body from cleaning fluids such as resins and solvents generated during cleaning of the mixing tank has been reduced compared to the past, and it has also become possible to improve product yield and quality due to the uniform composition.

The present invention applies to the composition of all mixtures that use a mixing tank, but is particularly applicable to the composition of raw materials such as casting, hand lay-up, and other resins and fillers when manufacturing structural parts and electrical insulation parts. It is effective for raw material tanks that mix and store materials, and is also effective for sealed mixing and stirring tanks such as pressurized tanks of material supply equipment such as pressurized gel casting equipment and liquid injection molding machines. has a large effect.

[Brief explanation of the drawing]

1 and 2 are sectional views showing a conventional mixing tank, and FIGS. 3 and 4 are sectional views showing a mixing tank according to the present invention. 1, 1', A, A'...Mixing tank body, 2,
2', B, B'...Mixture, 3,3', C...Stirring device, 5,5', E, E'...Flow pipe, 6,6', F
……valve.

Claims (1)

[Claims] 1. In a mixing tank for mixing liquid and particulate solids, a mixture outlet hole is provided in the vertical wall of the mixing tank or at a corresponding position, and the mixture flow pipe from the outlet hole to the discharge port is formed at a predetermined angle. A mixing tank characterized by being tilted upward.