Symons 7ft cone crusher is Nordberg spring cone crusher. It is an improved version of the YP2200 cone crusher with an installed capacity of 400 kW (YP2200 installed capacity 280kW). The spring crusher has been manufactured for over 100 years, and the model specifications are also available. There are also many series spring cone crusher. Their dust-tight seals are water-sealed. The mines, stone factories, and hydropower industries all over the world are still widely used. However, this crusher has many serious shortcomings. Although the manufacturer knows the defects of the crusher, it is impossible for the commercial advantage to make corresponding improvements on the crusher, but to develop another model, to lobby users to update older models of equipment to gain greater profits. For example, the HP and GP series crushers produced by Nordberg no longer use the water seal to prevent dust but use positive pressure wind to prevent dust and use them as a selling point to promote them. In fact, reasonable design improvements to the 7-foot cone crusher can also achieve the desired results.
Cone Crusher Crushing Principle
The crusher is driven by the motor to rotate the horizontal shaft, and the eccentric bushing is driven to make the moving cone rotate around a hanging point for conical swivel motion, and the moving cone is close to or away from the fixed cone to achieve the purpose of crushing the stone. The stone enters the crushing chamber from the upper part and is discharged from the lower part by gravity. In the process of crushing, the whole crusher is filled with dust. Due to the swinging motion of the crusher, a negative pressure is formed inside the crusher, so “breathing” occurs inside and outside. As a result, external dust enters the interior of the crusher, contaminating the lubrication system and causing damage to moving parts.
Water Seal Principle
The sealing system of the crusher consists of a water tank, a retaining ring, an inlet and outlet pipe, a vent pipe and a bowl-shaped tile seat (Fig. 1). The retaining ring is welded to the moving cone and swings with the moving cone. The sink is mounted on the bowl-shaped tile seat and is fixed. The dust-proof water enters the inner ring of the water tank from the water inlet pipe, overflows the barrier and enters the outer ring, and then is discharged by the return pipe. During operation, the circumference of the retaining ring is always immersed in water. If there is a certain point away from the water surface, the crusher will enter the dust.
- Retaining ring
- Moving Jaws
- Socklet liner
- 4.5mm Rubber gasket
- Sink mounting bolt
- Bowl gasket
The seal unwork reasons
There are two reasons that cause the seal cannot work.
- Some dust went into the cone crusher body. The depth of the retaining ring immersed in water is unreasonable. The retaining ring leaves the water at some point and the crusher will enter the dust.
- Some water went into cone crusher body. The water in and out is out of balance. First, the water level in the inner ring rises, causing dust water to be poured into the crusher; then leakage, and other unexpected factors. i) Difficult to control the amount of water. Influent and effluent must reach an absolute balance, the amount of water is small, and it is easy to cause dust deposition; if the amount of water is large, it is easy to raise the water level. In both cases, the water level in the tank is raised and the inside of the crusher is flooded; ii)Installation accuracy is difficult to control. In fact, the sink is only a half annular groove, which together with the bowl-shaped tile seat constitutes a complete annular water tank. Its seal is a washer on the lower part (see Figure 1). If a large tank ring body is fastened by only six M18 bolts at the edges, the reliability of the seal is greatly reduced and the water in the tank will inevitably penetrate from the lower part; iii) Bowl gasket and frame installation. The bowl-shaped tile seat is mounted on the frame. When installing, the acetylene-oxygen flame is used to heat the mouth of the frame with a diameter of 1537 mm. When the heat expands to the required size, the bowl-shaped tile seat is placed. Since the fall in place. Although it is hot-fit and interference fit, the contact surface is unlikely to reach 100%. The joint area of the general assembly surface is only 30% to 40%, and factors such as deformation and ellipse are not considered. When the water tank seeps, the mating surface of the bowl-shaped tile seat seeps. iV) Moving parts wear out. The moving cone of the crusher is located on the spherical bowl tile, so the entire crushing force is supported by the bowl-shaped spherical tile. During the operation, the spherical copper tile and the moving cone sphere are worn out, and the spherical copper tile wear is more obvious, especially when the lubrication is poor. When the spherical tile wears, the gap between the retaining ring and the water tank becomes smaller, the balance of the water flow in the water tank is broken, and the water level of the inner ring will rise, causing the dust water to flood or splash into the crusher.
There are not many problems with water seal dust prevention, and China is a big country with water resources, and we must cherish water. Wind (air) is inexhaustible, so wind and dust are both convenient and reliable. We use the following measures to achieve positive pressure dust:
- Remove the retaining ring and the sink, and install the active sealing ring on the moving cone, as shown in Figure 2.
- Install one cylinder on the bowl seat.
- The air inlet hole is machined on the bowl-shaped tile seat to allow the wind to enter the cylinder, so that a positive pressure difference is generated inside and outside the dustproof ring to prevent dust from entering.
- Install a “U” shaped tube on the return line to prevent pressure wind from leaking out and reduce the positive pressure at the ring;
- Install one blower, install one pressure gauge at the outlet of the blower, and install one exhaust valve to adjust the wind pressure. Sending pressurized air to the breathing port on the bowl tile and the horizontal axle box;
- The blower is interlocked with the main motor of the crusher to ensure that the fan operates when the crusher is turned on.
The principle of dust prevention is that the pressure wind enters the crusher through the air holes on the bowl-shaped tile seat, so that a positive pressure is formed in the crusher, and the dust is prevented from diffusing into the interior of the crusher to achieve the purpose of dust prevention. Since the water is not used, the crusher will not enter the water.