JPS62121634A - Method and apparatus for spray type granulation of heat-meltable substance - Google Patents

Abstract

PURPOSE:To prepare particles having a perfectly globular shape with good yield, by attracting particles formed by spraying to the central part of a spray pattern by line of electric force generated by voltage applied to the electrostatic charging electrode provided to the intermediate part of a jet group. CONSTITUTION:A heat-meltable substance F is injected and sprayed in a solid state by respectively operating electric or pneumatic type valves 3, 4. Because two spray patterns SA, SB are respectively directed outwardly, they do not cross or overlap. However, if voltage is applied to an electrode, line of electric force is generated and a large number of particles of the heat-meltable substance in the spray patterns are attracted to the center (Pa Pa', Pb Pb') by said line of electric force to be penetrated between two fan-shaped spray patterns SA, SB. That is, said particles fill the gap between the spray patterns SA, SB.

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, the method of granulating a hot melt material by spraying is to produce spherical particles by cooling and solidifying by two-fluid spray, airless spray, etc. or by water. In this case, in order to widen the above-mentioned gaps between the sprayed particles, it is necessary to enlarge the spray pattern as much as possible to increase the distance between the particles, and jet ports designed in accordance with this have been used. However, there is a limit to the expansion and expansion of the spray pattern using only the spout, and it has not been possible to sufficiently prevent the occurrence of mutual sticking. The motive of the present invention was to completely prevent these occurrences of mutual sticking by means other than the nozzle design.

An object of the present invention is to provide a method of manufacturing perfectly spherical particles with a good yield by expanding the spray pattern and preventing mutual adhesion of particles in a spray granulation method for heat-melting substances. It is.

In the first place, the present invention was developed by the applicant in June 1985.
This invention is based on the inventions of the patent application dated April 1988, ``Method for forming a spray pattern of powder coating and its spraying device,'' and the same patent application dated April 1985, ``Method of forming a spray pattern of fluid, and its spraying device.'' Through subsequent experiments, it was discovered that there is a different type of effect on granulation methods for objects other than those mentioned above, that is, heat-fusible substances, and this led to the filing of a new application.

The gist of the present invention is to spray a molten body of a heat-fusible substance from a plurality of jet ports at a necessary angle to each other so that the spray patterns do not overlap, and to spray particles in the spray. is drawn to the middle part of the plurality of dispersed spray patterns by electric lines of force generated by applying a voltage to the electrostatic charging electrode provided at the middle part of the plurality of jet nozzle groups,
This is a method of expanding the entire spray pattern, making the particle distribution more uniform, and creating gaps between the particles to prevent particles from sticking together.

The heat-melting substances targeted by the present invention include heat-melting natural and synthetic polymers, mixtures of these with low molecules, and various substances consisting of low molecules with relatively small masses. be. Further, the size of the particles produced is around 100 microns or less, and it is difficult to granulate particles larger than that.

Next, the granulation method according to the present invention will be explained.

Please refer to FIG. The spray device in the same figure is
This invention utilizes the spray device described in the above-mentioned patent application filed in April 1985 by the present applicant entitled "Method for Forming Spray Pattern of Fluid and Spray Apparatus". That is,
There are two or more spout ports 8A and 8B for the hot melt, and these are set at a required angle toward each other outward. Furthermore, an electrostatic charging electrode 10 is provided in the middle of these jet ports. The hot molten material F is simultaneously ejected and sprayed from these three ejection ports by actuation of electric or pneumatic operation valves 3 and 4, respectively. Since these two sprays SA and SB are directed outward as described above, they do not intersect or overlap. However, when a voltage is applied to the above electrode, electric lines of force are generated, which pulls many particles of the hot melt substance in the above spray towards the center (Pa->P
a';Pb-+Pb'.

......) Two fan-shaped spray patterns SA mentioned above
・Enter between SB. That is, two spray patterns S
It fills in the space between A and SB. In other words, both spray patterns are expanded, the distribution density of the particles is reduced, and the spacing between the particles becomes narrow, so that the particles no longer stick together closely.

A large number of spherical particles condense in this state and fall through the air, during which time they cool naturally and become spherical particles. However, their size is up to around 100 microns, and it is difficult to granulate larger amounts. The reason is that if the particle is a dog, its weight will naturally be a dog, and it will be difficult to obtain the effect of the suction action by electric lines of force.

In addition, although the above mentioned natural cooling of the particles after spraying, if the cooling is insufficient due to the substance, or if the particles are produced in a relatively large amount, or if the temperature of the spraying atmosphere is Measures such as lowering the temperature using a cooler etc. are used. In order to further increase the cooling effect, the present invention adds the following cooling method.

That is, high-pressure liquid gas is ejected into the spray chamber in which the above-described spray according to the present invention is performed.

For example, nitrogen gas, carbon dioxide gas, etc. As a result, the condensed particles of the sprayed heat-fusible substance are cooled and solidified in a short period of time, becoming perfectly spherical particles, completely preventing them from sticking to each other due to contact, external force, etc.

A structure based on the above method is shown in FIG. First, the spray device is a spray device described in Application No. 1 “Method for Forming Spray Patterns of Fluid and Spray Apparatus Therefor” dated April 1985 by the present applicant. That is, a plurality of spout ports 18A,
18B and an electrostatic charging electrode 20, the spray device is attached to the upper part of the spray chamber 13 that surrounds the entire periphery of the spray chamber 13, and has a high-pressure liquefied gas ejection port on the lower side wall side of the spray chamber. 15,16 are provided and are connected to a high pressure liquefied gas tank (not shown). A granulated particle transfer device is also provided at the bottom of the spray chamber. Although the hopper 19 is shown in the figure, other components such as a chute and a conveyor may also be attached.

In addition, as mentioned above, the spray device is as described in the claims in the specification of the patent application filed in April 1985 by the present applicant titled “Method for forming spray pattern of fluid and its spray device”. Three types of spray devices are applicable.

This is the one with the . The second type is one in which an intermediate adapter 20 is provided between the jets 21 and 22 and the jet ports 28A and 28B, as shown in FIG. 3, and the third one is as shown in FIG. 31, a plurality of spout ports 38A, 3
8B is provided.

Although the above figures show examples of three jetting cylinders, it is also possible to install three or more cylinders.

Further, although FIGS. 6 and 4 show fixed jet outlets, they can also be made movable by providing angle-variable jet outlet fittings.

As described above, according to the method of the present invention, a heated melt of a heat-fusible substance is sprayed from a plurality of jetting ports, and at the same time a voltage is applied to an electrostatic charging electrode, whereby a plurality of By filling in the blank areas of the spray pattern and further expanding the range of the spray pattern, the spacing between particles during spraying is increased, preventing particles from sticking to each other, and contributing to improving the yield of spherical particle production. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the granulation method by spraying a heat-melting substance according to the present invention (hereinafter all omitted for the present invention) Fig. 2 is a front view of the granulation device Fig. 6 is an intermediate adapter type of the spray device for the above Figure 4 is a front view of the same spray device as above, in which a single discharger is provided with a plurality of spout ports. Explanation of main symbols 1.2. I+, 12.21.22. @...Discharge device 3゜4.23, 24.33...Solenoid operated valve 5,6...Hinge plate 8A, 8B, 1
8A, 18B, 28A, 28B.

Claims (1)

[Claims] 1. In the spray granulation method of heat-melting substances, the heated melt is focused at a plurality of spout ports 8A and 8B each having a required angle α to each other, The spray patterns SA and SB are ejected so that they do not overlap, and the particles generated by these sprays are
The lines of electric force generated by applying a voltage to the electrostatic charging electrode 10 provided in the middle of the plurality of jet nozzle groups draw the spray pattern toward the center of the plurality of spray patterns, Thermal melting is characterized by filling the spaces in the spray pattern, expanding the spray pattern as a whole, making the particle distribution uniform, and preventing particles from coming into contact with each other or sticking to each other by creating spaces between each particle. Spray granulation method for sexual substances. 2. The spray-type granulation method of a heat-fusible substance according to claim 1, wherein the sprayed liquid particles in the air are sprayed with high-pressure liquefied gas to promote cooling and solidification. 3. The "spray" described in claims 1 and 2 is a "two-fluid spray" or an "airless spray." 4. In a spray type granulation device for heat-melting substances, a spray device having a plurality of focused jet ports 18A, 18B and an electrostatic charging electrode 20, etc. provided in the middle of the group of jet ports is used for spraying. A spray method for manufacturing a heat-melting substance is provided in the upper part of a spray chamber 13 that surrounds the entire periphery of the apparatus, and that jet ports 15 and 16 for high-pressure liquefied gas are provided in the lower part of the spray chamber. Grain device.