JPS6042872B2 - Granular material heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating device for granular materials such as foundry sand.

In the foundry industry, white sand molds are increasingly being used.

White sand molds use binders (organic and inorganic binders).

It produces white sand through a chemical reaction between the hardening agent and the hardening agent. This chemical reaction is affected by air temperature and sand temperature, so if high temperature foundry sand is used, the reaction rate will be too fast and molding will be difficult; on the other hand, if the sand temperature is too low, Problems have arisen in that the reaction rate is slow, it takes too much time to cure, and the amount of binder and curing agent used is large. In order to effectively cool down the high-temperature sand due to these problems, the inventors proposed a cooling device for heated granules (Japanese Patent Application No. 77391/1982).

In order to solve the drawbacks when the temperature of the sand is too low, the present invention is designed to uniformly disperse the sand in a heating tower and drop it, and to separate each grain of sand from the counterflow of warm air. The purpose of the present invention is to provide a heating device with a simple structure, which performs effective heating by bringing the objects into complete and uniform contact with each other.

Next, the specific configuration of the granular material heating device according to the present invention will be explained in detail with reference to the drawings.

1 and 2 show a first embodiment of the present invention, in which a heating tower 1 is supported and installed upright on a foundation surface by a frame (not shown).

The upper part of the heating tower 1 is provided with an inlet 2 for granular materials such as foundry sand, and the lower part is conical and a discharge valve 11 is provided at the bottom.
is provided. Hot air is supplied from the intake port 6 through a punching metal (perforated metal plate with many small holes punched out) installed inside the wind box 3.
It is led into the heating tower through the small hole 10, exchanges heat with the granules in the heating tower, enters the wind box 3 formed at the top of the heating tower, passes through the small hole in the punched metal 10, and is led to the exhaust port 4. The air is then exhausted through an exhaust fan (not shown).

On the other hand, granular materials such as foundry sand pass through the small holes (the diameter of the holes must be at least 3WLφ or more) in the punching metal 7 stretched at the top of the heating tower, and form rain on the surface of the punching metal 8-1 below. The granules fall upward, bounce back and pass through the small hole, and then pass through the punching metals 8-2, 8-3 and an appropriate number of punching metals below, while the particles are uniformly dispersed in the heating tower 1 and fall. Effective heating is possible because the individual particles come into uniform and complete contact with the hot air flowing in opposite directions. The heated granules accumulate at the bottom of the heating tower and are discharged from the discharge valve 11. Note that dispersion was good when the distance between each punching metal was at least 150 w1n or more and the falling acceleration was supported by the granules.
Also, the reason why a wind box 5 and a punching metal 10 are installed inside the wind box on the hot air intake side at the bottom of the heating tower is that the punching metal acts as a resistance to the hot air entering from the intake port 6, and the air circulates around the entire wind box. This has the effect of introducing hot air from all around the heating tower. Furthermore, since the cross-sectional area of the heating tower is increased in the wind box 3 on the exhaust side and the wind speed is reduced, particulate matter is not drawn into the exhaust side, and the wind speed within the heating tower can be further increased. child)
Being able to increase the wind speed means higher heating efficiency. In addition, a screen made of punched metal 9 is provided in the wind box 3 on the exhaust side, which has the same effect as the punched metal 10 on the suction side described above, and allows air to be exhausted from the entire circumference of the heating tower. This allows for even air flow inside.

Next, a second embodiment shown in FIGS. 3 and 4 will be described.

In this embodiment, a punching metal 12 is newly installed in the heating tower having the configuration shown in the first embodiment.
The effect of the punching metal 12 is that the granules that fall are uniformly dispersed in the shape of raindrops inside the heating tower by the punching metal 8 at the top of the heating tower, are first splashed off on the surface of the punching metal 12-1, and then the punched metal It passes through the small hole and falls one after another onto the surface of the punched metal at the bottom.

Therefore, compared to the first embodiment, by providing the punching metal 12, the residence time of the granules in the heating tower becomes longer, and if the interval between the punching metals is set to 150 WI 1L or more, it is possible to increase the retention time on the punching metal surface. Since a jumping phenomenon of the granules occurs, a layer of sand is not formed, and the granules can be heated more completely. In addition, the cross-sectional area of the air passing through the heating tower becomes smaller at the punched metal 12 and the flow velocity increases, so it can be expected that the heating effect will be further increased.
In this case, the number of stages of the punching metal 12 is determined as necessary, and it goes without saying that the five stages shown in FIG. 3 is just one example. The shape of the punched metal may be simply a metal plate with small holes punched out, but as shown in the partially enlarged view of the punched metal shown in Figure 4, it is possible to form a punched metal with a flared shape that stretches the bottom side. It can be used to reduce air resistance.

Air passes in the direction of the arrow. FIG. 5 shows a third embodiment of the present invention, which has the same structure as the first and second embodiments, but includes a dust collector 13 that also serves as an exhaust fan, a heat exchanger 15 (aluminum fin coil), and a heat medium. It is equipped with a heating device 16 (boiler), ducts 4'', 6'', and 14 that connect them, and a vibrator 17 that circulates a heat medium.

Although a cyclone type dust collector 13 which also serves as an exhaust fan is shown in the figure, other general dust collectors may be used.

The air sent out from the dust collector 13 passes through the duct 14,
While passing through the heat exchanger 15 heated by the heat medium sent from the heating device 16, the air is forcibly heated and becomes warm air.

The warm air enters the heating tower 1 through the duct 6'' and the wind box 5, heats the granules falling from the top, and enters the dust collector 13 through the wind box 3 and the duct 4'', where the dust and air are removed. The separated air is recirculated. In this embodiment, the hot air is forcibly heated, so that the particulate matter passing through the heating tower is easily heated to an appropriate temperature. As described above, according to the granular material heating device according to the present invention, the granular materials fall in the heating tower in a uniformly dispersed state in the form of raindrops, so that the heating effect of the counterflow of hot air is reduced. Significantly improved.

Further, due to the effect of the punching metal provided in several stages within the heating tower, the particulate matter is kept in a dispersed state, and the residence time within the heating tower can be extended. From this aspect as well, the heating effect j can be improved. Furthermore, since the heating device of the present invention has no movable parts in the heating tower, it is easy to maintain and is effective as a heating device for granular materials such as foundry sand.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of a granular material heating device according to the present invention, FIG. 2 is a front view of the heating device, and FIG. 3 is a sectional view showing a second embodiment. FIG. 4 is a partially enlarged sectional view showing an example of the punched metal same as above, and FIG. 5 is a front view of the third embodiment. 1...Heating tower, 2...Intake port, 3,5
...Wind box, 4...Exhaust port, 4″, 6″
...Duct, 8...Punching metal, 1
3...Dust collector, 14...Duct, 15.
... Heat exchanger, 16 ... Heat medium heating machine, 1
7... Heat medium circulation vibe.

Claims (1)

[Scope of Claims] 1. A heating tower installed upright has a granular material intake in the upper part and a discharge valve in the lower part, and has an air intake and a large number of small holes punched out. A wind box with a built-in metal plate is installed at the bottom, and a wind box with a perforated metal plate inside and an exhaust port is installed at the top, and particulate matter is dispersed between the wind box and the intake in the heating tower. A heating device for granular materials, characterized in that a perforated metal plate having a large number of small holes punched therein is provided with an appropriate number of stages at appropriate intervals. 2 In the heating tower, between the upper wind box and the lower wind box, a perforated metal plate with a large number of small holes punched out to control the falling speed of particulate matter was provided in an appropriate number at appropriate intervals. A heating device for granular materials according to claim 1, characterized in that: 3. The device according to claim 1 or 2, characterized in that a dust collector, a heat exchanger, and a heat medium heater are connected to a heating tower through a duct and a heat medium circulation pipe. Granular material heating device.