Green Sand Molding Line sand recycling equipment

1. The quality of green sand determines the performance of molding sand
1.1 Sand performance and sand mixing principle
The production of fine and high-grade castings by modern high-speed and high-pressure molding machines requires good comprehensive performance, flow forming performance and uniformity of the molding sand, the compaction rate is 36%~42%, the strength is 0.17~0.20MPa, and the moisture content is 3.4% or less. In order to solve the contradiction of molding sand performance, it is necessary to require the sand mixer to have a relatively high mixing capacity, and to have relatively high requirements on the mixing mechanism, main parameters and the stability and reliability of the equipment dynamic structure. The primary condition for improving the mixing quality is the "sufficient force" of the sand mixing: the circumferential speed of the sand mixing rotor is selected to be 18~22m/s, which can give the sub-mixture enough "spinning force". In addition, the use of mixing force should be fully utilized and mutual interference should be avoided, so that the material entering the mixing area of the rotor is "large". The speed of the scraper that pushes sand and mixes to the rotor is generally low (1~2m/s). If the speed is too high, the power will be greatly increased. If the rotor blade uses a horizontal straight blade to push out the material, the material pushed by the scraper will be pushed out in the opposite direction, which is not conducive to rubbing. Therefore, it is very necessary to use inclined blades. The arc scraper pushes the material from the horizontal direction to the downward inclination of the rotor by 159~18°. Because the front edge of the blade has an inclination angle of 30°, the blades form a double helix cross arrangement on the rotor. The mixing area of the material entering the rotor is relatively large, which improves the mixing space of the material.

1.2 The new GS25-132 high-efficiency rotor sand mixer has a structural design: the disc diameter is 2500mm, the total power is about 242kW, and the production capacity is nearly 65t/h. The circle and arc scraper are all made of wear-resistant engineering plastic plate lined with non-stick material and small friction coefficient, which reduces the workload of daily maintenance and cleaning, and saves about 20% of the operating power and energy consumption of the sand mixer. In order to ensure reasonably high sand performance and production capacity, a reasonable rotor drive power must be configured accordingly. Usually, the rotor drive power (kW)/wet compressive strength (MPa) and the actual productivity (t/h) ≥ 11 are selected as the cost-effectiveness factor for evaluating the equipment.

2. Large-scale falling sand cleaning and cooling drum
2.1 L33 double-layer falling sand cleaning and cooling drum, an appropriate amount of iron star medium is configured in the inner and outer double-layer rollers to participate in the circulation flow, participate in rolling wrapping and buffer the collision of the castings, which can protect the edges and corners of the castings and is easy to clean. The iron star medium flow is repeatedly rubbed to make the castings smooth and clean, without black sticky sand, eliminating the need for secondary primary cleaning, and can be directly transported to the shot blasting cleaning process.

2.2 After the old sand is separated and peeled off from the casting, it is immediately crushed and screened at the feeding end. No humidification is required before and within the drum during the sanding, cleaning process. Only a small amount of humidification is required in the subsequent sand treatment system (depending on the temperature of the old sand), which reduces the burden on the cooling and dust removal of the old sand. In contrast to the single-layer falling sand cooling drum, since the old sand is baked by the hot castings, the thermal diffusion time is long. Subsequent old sand treatment and sand mixing quality control bring great difficulties, such as excessive spray humidification in the cylinder, resulting in rolling sticky sand, sand blocking and even backflow, and affecting the subsequent machining of castings.

2.3 The hardened old sand agglomerates that are separated and peeled off on the hot casting are rolled and crushed by the iron star medium flow, and are discharged through the 14-16mm grid gap on the inner casing. The old sand recovery rate is nearly 100%.

2.4 Double-layer falling sand cleaning The cooling roller works in a closed state, its dust removal effect is good, and the working conditions are clean. The engineering nylon idler used has a long service life, which can protect the main roller table of the drum from wear and absorb the running noise of the drum. The friction between the iron star and the simplified body produces noise. Generally, the simplified version should be installed in the pit or covered with a sound-absorbing lining or a full cover to absorb sound, so as to reduce the noise under working conditions to below 80dB(A).

2.5 There are spiral deflectors with different heights in the cylinder, so that the castings, castings, iron stars, etc. can be transported smoothly, and the productivity is more than 3 times that of a single-layer drum of the same diameter. The rotation speed of the drum can be reduced to ensure sufficient production capacity while meeting process performance. When the rotating speed of the drum is reduced to 1~1.5r/min, it can adapt to the separation of large and medium-sized castings with a diameter of 400~500mm.

2.6 L32 type single-layer falling sand cleaning cooling drum In order to avoid the phenomenon that the castings are bumped against each other due to the poor discharge of the single-layer drum with a closed cone, a straight cylindrical drum is used, and the drum speed is reduced from 3~5r/min to 1~1.5r/min. The castings of the matching sand casting molding machine are shaken off, the castings are not bruised, and the equipment runs well. In addition, on the horizontal parting molding line of the 1000mmx800mm sand box, the use of the medium and large castings, only the falling sand is separated in the cylinder, and the shakeout machine is equipped outside the cylinder to separate the old sand, and the operation process is excellent. However, the single-layer falling sand rolling has a common disadvantage that a small amount of sand and a small amount of old sand agglomerates are discharged from the barrel end of the casting, so the rotation speed can be adjusted according to the type of casting.

Qingdao Sanzhuji Equipment Manufacturing Co., Ltd. specializes in the production of Green Sand Molding Line,Self-hardening sand molding line,foundry machines,Sand molding machine,Sand casting equipment,sand mixer,GS high efficiency rotary mixer,Resin sand mixer,no-bake resin sand mixer,Jolt squeeze molding machine/Jolt-squeezing moulding machines,Multi- Piston Moulding Machine/Hydraulic multi-piston moulding machine,sand casting molding machine,sand reclamation equipment，foundry molding machine,flaskless moulding machine,shot blasting machine,dust collector,according to the amount of old sand recovered Carry out plan customization, and provide sand reclamation equipment installation, commissioning, and training. Welcome guests to visit the factory.