Introduce

In the crushing production lines of mining, building materials, and other industries, the secondary mineral sizer tooth plates, as the core wear-prone components, directly affect the installation efficiency and ease of replacement, which in turn impacts equipment downtime and production efficiency.

The traditional installation method of tooth plates often becomes a maintenance pain point due to its complex structure and difficult disassembly. However, the tooth plates of secondary Mineral Sizer have been adjusted to adopt a single-sided dovetail groove installation method, which has successfully overcome the difficulty of disassembly.

What is a single-sided dovetail groove?

A single-sided dovetail groove is an asymmetrical groove structure consisting of an inclined guiding slope (usually with an inclination angle of 50° - 60°, commonly 55° in secondary mineral sizer) and a vertical positioning plane. The entire structure is in the shape of a "single-sided narrowing" wedge — similar to a "∠" shaped groove, with only one side forming an inclined mating surface that can match accessories (such as the dovetail mortise of a tooth plate).

In the secondary mineral sizer, the single-sided dovetail groove is the core structure for connecting the tooth plate and the roller body. It complements the inclined surface of the insert strip clamping block, and then the broken tooth plate is installed onto the tooth plate fixing seat, forming a face-to-face connection. The role of the bolts is transformed into fixing the insert strip clamping block. This design directly serves the requirements of "stability, impact resistance and maintenance convenience" for the crushing operation.

Replacement steps for secondary mineral sizer worn tooth plates

Preparation before replacement

Equipment Shutdown and Safety Assurance

Stop the operation of the Secondary Mineral Sizer and its associated equipment, cut off the main power supply, and hang a "Do Not Close Switch" warning sign to ensure that the roller body is completely stopped and to avoid risks caused by inertia rotation.

Clean the crushing chamber and the area around the teeth plate of any remaining materials. Use tools to remove large pieces of ore, then use compressed air to blow away fine dust to prevent materials from falling or getting stuck during replacement.

Tools and spare parts preparation

Prepare a wrench (matching the bolt specification for the fixed insert block), a rubber mallet, a crowbar (with a blunt head to avoid damaging the dovetail groove), a cleaning cloth, and sandpaper.

Confirm the specification of the new tooth plate, check if the dovetail joint size and the inclined angle of the surface match the single-sided dovetail groove, and ensure it can precisely complement the inclined surface of the insert block.

Removing the old tooth plate

Loosen the bolts securing the clamping blocks

Since the bolts are only used to secure the clamping blocks, locate the corresponding bolts and loosen them one by one (note the bolt positions to avoid confusion). At this point, the bolts are no longer directly connected to the tooth plate, and loosening them will release the clamping force of the clamping blocks.

If the bolts are stuck due to long-term vibration, spray a small amount of lubricant first, wait a moment, and then proceed with removal. Do not forcefully turn the bolts, as this may cause damage.

Removing the tooth bar clamping block

Gently tap the end of the tooth bar clamping block with a rubber hammer to slowly withdraw it along the single-sided dovetail groove slope. Since the tooth bar clamping block and the single-sided dovetail groove slope are complementary, they maintain stability during withdrawal to avoid scratching the groove slope.

If the tooth plate clamping block is tightly secured, use a pry bar to gently pry it at the gap between the clamping block and the tooth plate mounting bracket, while simultaneously tapping with a rubber hammer to assist in removal.

Remove the old tooth plate

The old tooth plate is installed on the tooth plate mounting bracket via a face-to-face connection, with the dovetail tenon embedded in the single-sided dovetail groove. Gently tap the end of the old tooth plate with a rubber hammer (avoid the tooth tips to prevent cracking) to allow it to slide along the tapered surface of the dovetail groove.

If the tooth plate is stuck due to wear, use sandpaper to remove any material residue or burrs inside the dovetail groove, then pull out the old tooth plate along the tapered surface.

Installation of new tooth plates

Cleaning and inspection of the installation surface

Wipe the single-sided dovetail groove, mineral sizer tooth plate fixing seat, and bevel of the clamping block with a clean cloth to remove oil, dust, and debris. If the dovetail groove bevel has slight wear or burrs, sand it smooth with sandpaper.

Inspect the tapered surface of the new tooth plate's dovetail tenon, remove any surface burrs, and ensure it fits snugly against the tapered surfaces of the single-sided dovetail groove and the tooth plate clamping block.

Install the new tooth plate.

Align the dovetail tenon of the new tooth plate with the entrance of the single-sided dovetail groove, and push it smoothly into the tooth plate mounting bracket along the inclined surface. During the process, gently tap the side of the tooth plate with a rubber hammer (apply even force) until it is fully seated, ensuring a tight face-to-face connection with the tooth plate mounting bracket.

Check the position of the new tooth plate to ensure that its tooth surface is flush with the other tooth plates on the roller body and that the gaps between adjacent tooth plates are uniform to prevent material jamming or uneven force distribution during subsequent crushing.

Install and secure the insert clamping block

Place the insert clamping block in the corresponding position, ensuring that its inclined surface precisely complements the inclined surface of the single-sided dovetail groove. Gently tap it to ensure a tight fit with the new tooth plate and dovetail groove.

Secure the tooth plate clamping blocks with bolts and tighten them to the specified torque (avoid over-tightening, which may cause deformation of the clamping blocks or dovetail grooves). The pressure from the clamping blocks ensures a stable surface connection between the new tooth plate, the tooth plate mounting bracket, and the single-sided dovetail groove.

Post-replacement inspection

Installation quality inspection

Shake the new tooth plate by hand to ensure there is no loosening; check whether the clamping block is tightly fitted with the single-sided dovetail groove and the new tooth plate, with no obvious gaps.

Confirm that the bolts are tightened and there are no signs of loosening to prevent the clamping block from shifting during equipment operation.

Testing and verification

Remove the warning signs, connect the power supply, and conduct an empty load test for 1-2 minutes, listening for any abnormal noises (such as friction or impact sounds). If any abnormalities are detected, immediately shut down the machine for inspection.

After confirming normal operation under empty load conditions, conduct a loaded test, observing the crushing effect to ensure the tooth plate operates smoothly and the crushed particle size meets requirements.

The Value of Single-sided Dovetail Grooves in Secondary Mineral Sizers

The core requirements of secondary mineral sizers are “efficient crushing (uniform particle size), stable operation (impact resistance), and low maintenance costs (easy replacement of wear parts).” The design of single-sided dovetail grooves perfectly matches these requirements:

Impact Resistance and Stability

The Secondary Mineral Sizer processes minerals with high hardness (e.g., iron ore, copper ore), and the impact force on the tooth plates during crushing can reach several tons. The single-sided dovetail groove forms a surface connection with the wedge clamping block through complementary inclined surfaces, dispersing the impact force over a larger contact area. Combined with “inclined surface load-bearing + wedge clamping” and bolt fixation of the wedge clamping block, the impact force is distributed across the entire roller body (rather than localized bolts), preventing tooth plate loosening, detachment, or fracture.

Precise positioning

For the secondary crushing process, the ore needs to be further crushed from "100-200mm after coarse crushing" to "20-50mm". It is required that the spacing between the tooth tips of the teeth plate and the depth of meshing be strictly consistent. The guiding and positioning function of the single-sided dovetail groove, combined with the precise cooperation with the clamping block of the insert strip, can ensure that the installation height and angle of each tooth plate are completely uniform, avoiding "over-crushing" caused by individual tooth plates protruding or "insufficient crushing" caused by depressions.

Convenient maintenance

Tooth plates are wear parts (they must be replaced promptly after wear, otherwise crushing efficiency will be affected). The single-sided dovetail groove's “slide-in installation + wedge block fastening” requires no specialized tools, and bolts only secure the insert clamping blocks, allowing ordinary maintenance personnel to operate. The tooth plate replacement time for a single unit can be controlled within 1-2 hours (traditional bolt fixation may require 4-6 hours), significantly reducing production line downtime losses.

Conclusion

In the secondary mineral sizer, the single-sided dovetail groove is a typical design that combines "structural mechanics" with "operating conditions requirements."

It enhances structural stability by forming a face connection with the clamping block of the insert and fixing the clamping block with bolts; its asymmetrical inclined surface structure specifically withstands crushing impacts, and the guiding and positioning characteristics ensure the crushing accuracy. The features that allow for tightening and easy maintenance cater to the frequent replacement needs of the tooth plates.

In simple terms, it "solves a big problem with a simple structure"—it "not only makes the tooth plates as stable as a rock" during intense operations but also makes the replacement and maintenance "time-saving and labor-saving," which is the core reason why it is adopted in mineral crushing equipment.