The angle between fixed jaw and movable jaw of jaw crusher is called phasing angle. When the material is crushed, the material is squeezed by the jaw plate. The size of phasing angle directly affects the productivity of the crusher and the height of the crushing chamber. So how to choose the right size of phasing angle?

Phasing angle small can improve the crusher's raw friction is difficult to filter, but in a certain crushing ratio conditions, and increase the height of the crushing chamber; phasing angle is large, will make the crushing chamber height is reduced, but the productivity will also decline. In addition, the maximum phasing angle can not exceed the permissible value of the biting material. The phasing angle is generally selected according to the condition of maximum crushing ratio, i.e. the maximum phasing angle is selected under the condition of ensuring that the material in the crushing cavity does not slide upward.

When the material is squeezed in the crushing cavity, the pressure of the movable jaw and the fixed jaw on the material is P1 and P2 respectively, while the friction between the two jaws and the material is: F1=fP1 and F2=fP2, of which f is the coefficient of friction between the material and the jaw plate, which is generally 0.25~0.3. Considering the condition that the material is not extruded upward, and that the horizontal force acting on the material is reasonably equal to zero, it can be obtained that:

α≤2Ψ, α is the phasing angle, Ψ is the friction angle between the material and the jaw plate.

In actual production, in order to ensure safety, the phasing angle of the jaw crusher with the friction is very sad to take 65% of the theoretical value, that is:

α=0.65αmax=18°~22°, considering the theoretical value and actual demand, the phasing angle of 22° is selected in the design.

There are three kinds of arrangement of fixed and movable jaw plates of jaw crusher: movable jaw plate is tilted at an angle of α relative to the vertical direction, and fixed jaw plate is vertical; fixed and movable jaw plates have a tilt respectively; fixed jaw plate is tilted at an angle of α, and movable jaw plate is vertical. In the design, the product size is required to be high, in order to ensure the product size and shape, taking into account the shape and size of the crushed material and other characteristics, the most suitable arrangement of the fixed and movable jaw needs to be selected.