Crusher identification: which machine is commonly described as a combination of a jaw crusher and a roller crusher due to its continuous compression and gyrating action?

Introduction / Context:
Primary and secondary crushers use different mechanical principles. Jaw crushers apply intermittent compression with a moving plate; roll crushers apply continuous compression with two cylinders. Gyratory crushers blend features of both by using a gyrating cone within a stationary shell, creating continuous, high-capacity compression suitable for large lumps.

Given Data / Assumptions:

• Objective: identify the crusher whose action resembles a combination of jaw and roll mechanisms.
• Feed: large, hard rock typical of primary stages.
• Requirement: continuous throughput and uniform product for downstream processing.

Concept / Approach:
A gyratory crusher uses a conical head that gyrates inside a concave bowl. Material is continuously nipped and compressed as it moves downward, akin to the continuous compression of rolls, while the nip and release across the crushing chamber share conceptual similarity with jaw crushers. Hence, it is often described as combining both jaw-like nip mechanics and roll-like continuous duty.

Step-by-Step Solution:
List mechanisms: jaw (intermittent compression), roll (continuous compression), gyratory (gyrating cone with continuous compression).Match to description: the “combination” characterization fits the gyratory crusher.Eliminate mills (rod/ball) and fluid energy mill—used for fine grinding, not primary compression crushing.

Verification / Alternative check:
Standard flowsheets in mine operations show gyratories as primary units where very high capacity and large feed openings are required—consistent with the combination description.

Why Other Options Are Wrong:
Rod mill, ball mill, fluid energy mill: these are grinding mills relying on media or jets; they do not combine jaw/roll crushing actions.

Common Pitfalls:
Associating “fluid energy” with high power and mistakenly assuming primary breakage capability; jet mills are for ultrafines, not coarse crushing.

Final Answer:
Gyratory crusher