JPS61202745A - Method for reclaiming molding sand and improving quality thereof - Google Patents

Abstract

PURPOSE:To recycle thoroughly sand and to simplify a sand treating installation disposed in series with 3 units of rotary reclaimers by supplying intermittently the sand to said installation. CONSTITUTION:The sand to be reclaimed is supplied to the 1st bucket elevator 20 and after the sand is treated with the rotary reclaimers 24, pulverous powder, etc. are removed therefrom in a classifier 25 and the sand is sent to the succeeding stage by the 2nd bucket elevator 27. The sand is supplied intermittently at about 3-5t/hr rate and the treatment is completed simply by passing once the sand through 3 units of the rotary reclaimers in series. After the sand is supplied for several seconds at about 3-5t/hr rate, the supply of the sand is stopped for a prescribed period and the rotary claimers 24 are rotated. The sand in the fixed layer on the inside walls of the drums and shelves of the reclaimers 24 is rubbed and the collision and rubbing are individually repeated by the circulation motion during the time when the sand stagnates in the drums and shelves. The sand is thus reclaimed. The reclamation of the sand is thus completed with one time of the treatment by selecting adequately the rate of the time for the intermittent supply without the need for repetitive use of the installation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for regenerating and improving the quality of foundry sand.

[Conventional technology]

Various devices have been used in the past to regenerate foundry sand and improve its quality, and the one shown in Figure 2 is one of the typical devices, and is a partial cross-section of a high-performance rotary reclaimer. It is a diagram. In the figure, (1) is the drive device, (
2) is a rotary drum, (3) is a shelf ring, (4) is a
) is the shelf, (4a) the lip of the hatch, (5) is the gap between the rotary drum (2) and the shelf ring (3), (6) is the sand supply hole, and (7) is the lip of the drum (2). Fixed sand that remains on the inner wall of the drum due to centrifugal force due to rotation, (8) is stagnant sand on the inner wall of shelf (4), (9) sand that remains in the i-shelf (4) and drum (2), and Ql is the stagnant sand ( 9) In the circulation system path, αυ is the outflowing sand across the gap (5), and α2 is the outflowing sand overflowing the peripheral wall of the shelf (4).

The drive device (1) is operated to fully rotate the rotary drum (2) and supply the sand to be recycled through the sand supply hole (6).

The supplied sand is transferred to the drum (2) by rotation of the drum (2).
Some of the sand accumulates on the inner wall of the drum (7) and eventually fills the drum, overflows from the peripheral wall of the drum (2), and flows out through the gap (5). 0υ is the sand flowing out from the gap (5). Amount of sand supplied CkI
When yhr is larger than the amount Dklhr of the outflow sand aυ, the sand further fills the shelf (4), and eventually overflows the inner wall of the shelf (4) to become outflow sand α2 and flow out to the outside. The amount of this sand α2 tEwhr
, the amount of sand (9) remaining in the rotary drum (2) and shelf (4)? Q kli/hr % If the amount of sand that circulates like αO in the drum (2) and shelf (4) is Fkg//hr, then ■ the sand reaches the shelf (
The conditions for geo-buff flow from the surrounding wall of 4) are C>D (When 2 sand flows from the surrounding wall of /L7(4) at a rate of υEkg/hr, C=D+E ■ Residence time of sand T For hr, the relational expression T=Q/CO holds true.

In this state, the accumulated sand (9) in the drum (2) is removed from the drum (2).
Due to the rotation of 2), there is intense friction L with the fixed sand (7) on the inner wall of the drum, and furthermore, the accumulated sand (9) in the drum and shelf undergoes internal renewal due to its own circulation movement and the shelf (4).
Sand deposits are removed by collision with stagnant sand on the inner wall.
Ru. Thus, the stagnant sand (9) has its own circulation movement and the fixed sand (
7), it is evenly and uniformly regenerated by collision with the stagnant sand (8) and friction, and flows out through the gap (5) or overflows the inner wall of the shelf (4). This action not only removes sand deposits, but also smooths out the edges of the sand grains, reducing the total amount of binder added, thereby reducing costs.

The sand regeneration effect described above is possible due to the existence of the gap (5), and if the gap (5) is too large, C=D and the accumulated sand becomes zero, and the above-mentioned regeneration effect becomes ineffective. It is now.

[Problem that the invention seeks to solve]

By the way, in the conventional sand recycling method, the conditions C>D are important! :l, C=D, as described above, the processing effect is lost. Since the gap (5) expands due to wear during operation, D tends to increase. Further, the lower limit of C is usually 3 t/hr', and if it is less than that, the sand will not be retained sufficiently and the regeneration effect will not be accompanied. Furthermore, the residence time of the sand after the regeneration treatment is 180 seconds in the case of green sand, and when processing at 3 t/hr, it is necessary to repeat the regeneration treatment using the reclaimer 18 times. Figure 6 is a configuration diagram of the second raw processing equipment, where ■ is the first packet elevator, Q]) is the switching gate, (a), (22') are the hopper, (to), (23') are A switching gate, (c) the rotary reclaimer 1, (c) a classifier, (e) a switching gate, and (5) a second bucket elevator.

As shown in the figure, three rotary reclaimers I are arranged in series, and this equipment is used six times for sand reclamation. Therefore, a switching gate Qυ, PA is provided,
The hoppers (A) and (22') have two chambers in preparation for repeated use of the equipment. In order to satisfy C>Di, 3 t/hr of sand is continuously supplied and the sand is returned six times, so the sand processing capacity of the equipment is 0.5 t/hr.

As mentioned above, sand regeneration requires repeated use of processing equipment, which complicates the equipment and increases costs.As the number of processing increases, sand loss also increases, and equipment to recover the sand is also required. As a result, the equipment becomes complicated and the cost increases, which is a problem with the conventional method.

The present invention provides for the regeneration and quality improvement of used foundry sand.
The aim is to provide a low-cost method.

[Means for solving problems]

In a sand processing facility in which three Tsumugi rotary reclaimers are arranged in series, sand is intermittently supplied to the facility.

[Effect]

If the sand supply is intermittent, even if the sand supply is stopped, there will be sufficient friction with fixed sand and stagnant sand, and collision friction due to sand circulation 1, so that the sand regeneration effect will not be complete. Become. Therefore, by appropriately selecting the above-mentioned intermittent time, it becomes unnecessary to repeatedly use the sand processing equipment, the equipment is simplified, the cost is reduced, and the effect of improving the quality of sand is also improved. During intermittent supply, it is necessary to satisfy the condition C>D.
Once the sand has stagnated, it continues to stagnate even if the supply is stopped (even if C=0), so we applied this point to the fact that the stagnation time can be extended until the next supply.

[Embodiments of the invention]

FIG. 1 is a block diagram of sand processing equipment showing one embodiment of the present invention. In the figure, ■, (a), (c), (c) and V) are the same parts as the conventional equipment.

As shown in the figure, six rotary reclaimers (C) are arranged in series, and the configuration is different from the conventional equipment shown in Figure 3, with the switching gate @1), m, and one hopper chamber omitted. .

The sand to be reclaimed is supplied to the first packet elevator (2), treated by the rotary reclaimer (3), then fine powder etc. are removed by the classifier (3), and sent to the next process by the second packet elevator.

Sand was supplied intermittently at a rate of 6 to 5 t/hr.
Processing is completed by passing the machine through the rotary reclaimer all in series once. After supplying sand at a rate of 3 to 5 t/hr for several seconds, the supply of sand is stopped for a predetermined period of time, and when the rotary reclaimer (c) is rotated, the drum (2
) and shelf (4), it rubs against the fixed layer of sand on the inner wall of one drum or shelf, and regeneration is performed by repeating the collision and friction of each drum and shelf by circulation movement, so the time of intermittent supply is By appropriately selecting the distribution, sand regeneration can be completed in a single treatment without the need for repeated use of equipment.

As a result, as shown in Figure 1, the processing equipment is simpler than conventional equipment, and sand loss due to repeated processing is drastically reduced.

〔Effect of the invention〕

In the sand recycling process, the present invention performs intermittent supply and stops the repeated use of the recycling equipment and uses it only once.
Compared to conventional methods, we were able to achieve the following superior effects.

(1) Sand recycling equipment has been simplified and equipment costs have been reduced. (2) Sand loss due to repeated use of equipment has been drastically reduced.

(3) Improved sand quality (improved purity, improved particle shape, and adjusted particle size distribution) was achieved.

(4) Through the above, significant cost reductions were achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a sand recycling facility showing an embodiment of the present invention, FIG. 2 is a partial cross-sectional view of a rotor I717 cremer,
FIG. 6 is a block diagram of a conventional regeneration treatment facility. In the figure, ■ is the first packet elevator, (A) is the hopper, (B) is the gate, (C) is the rotary reclaimer, (C) is the classifier, and @ is the second elevator.

Claims (1)

[Claims] A method for regenerating and improving the quality of foundry sand, which comprises supplying the foundry sand intermittently in equipment for regenerating and improving the quality of foundry sand.