Crusher for mineral materials or recycled materials
A crusher includes first and second crusher bodies defining a crushing gap. A hydraulic cylinder is coupled to one of the crusher bodies to adjust a width of the crushing gap. A pressure relief valve includes a pressure chamber communicated with the hydraulic cylinder. A pressure relief piston is movable between a closed position and an open position. The closed position blocks a fluid connection between the pressure chamber and a pressure equalization area exterior of the pressure relief valve. The pressure relief piston includes at least one piston pressure surface delimiting the pressure chamber in the closed position transversely to the actuating direction of the piston, wherein in the closed position of the pressure relief piston a projection of the at least one piston pressure surface in a projection plane transverse to the actuating direction of the pressure relief piston delimits only a part of the pressure chamber transverse to the actuating direction of the pressure relief piston.
1 . A crusher for mineral materials or recycling materials, comprising:
a first crusher body:
a movable second crusher body arranged such that a crushing gap is formed between the first and second crusher bodies;
a hydraulic cylinder coupled to one of the crusher bodies and configured to permit an evasive motion of the coupled one of the crusher bodies to increase a width of the crushing gap, the hydraulic cylinder including a pressure space; and
a pressure relief valve including:
a pressure chamber communicated with the pressure space of the hydraulic cylinder;
a pressure relief piston movable in an actuating direction between a closed position and an open position, wherein a fluid-conveying connection between the pressure chamber and a pressure equalization area exterior of the pressure relief valve is blocked in the closed position and is at least partially open in the open position; and
the pressure relief piston including at least one piston pressure surface delimiting the pressure chamber in the closed position transversely to the actuating direction of the piston, wherein in the closed position of the pressure relief piston a projection of the at least one piston pressure surface in a projection plane transverse to the actuating direction of the pressure relief piston delimits only a part of the pressure chamber transverse to the actuating direction of the pressure relief piston.
2 . The crusher of claim 1 , wherein the pressure relief valve further comprises:
a bridging device relative to which the pressure relief piston is adjustable, the bridging device including at least one pressure surface section delimiting the pressure chamber transversely to the actuating direction of the pressure relief piston, wherein a projection of the at least one pressure surface section in the actuating direction of the pressure relief piston does not completely cover the at least one piston pressure surface of the pressure relief piston.
3 . The crusher of claim 2 , wherein:
a surface normal of the at least one piston pressure surface of the pressure relief piston and a surface normal of the at least one pressure surface section of the bridging device point in the same direction.
4 . The crusher of claim 1 , wherein the pressure relief valve further comprises:
a housing forming the pressure chamber and having an inner cylinder wall; and
wherein the pressure relief piston is annular and includes a cylindrical outer piston wall received in the inner cylinder wall of the housing, the pressure relief piston further including a cylindrical inner piston wall.
5 . The crusher of claim 1 , wherein:
the pressure relief piston includes a support section extending outside of the pressure chamber; and
the pressure relief valve further includes a spring engaging the support section and configured to transfer a preload force into the pressure relief piston in the closing direction in order to preload the pressure relief piston against a valve seat.
6 . The crusher of claim 1 , wherein the pressure relief valve further comprises:
a housing having an inner cylinder wall;
a bridging device including at least one pressure surface section delimiting the pressure chamber transversely to the actuating direction of the pressure relief piston; and
wherein the bridging device is connected to the housing by a connection section and the bridging device is adjustable in position relative to the housing in the actuating direction and/or transversely to the actuating direction of the pressure relief piston.
7 . The crusher of claim 1 , wherein the pressure relief valve further comprises:
a housing having an inner cylinder wall;
a bridging device including at least one pressure surface section delimiting the pressure chamber transversely to the actuating direction of the pressure relief piston; and
wherein the bridging device includes a beam and a head mounted on the beam within an interior of the housing, the head forming the at least one pressure surface section.
8 . The crusher of claim 1 , wherein:
the pressure relief piston delimits a low-pressure area of the pressure relief valve and the pressure relief piston is moved into the low-pressure area when the pressure relief piston is moved from the closed position to the open position.
9 . The crusher of claim 8 , wherein:
the low-pressure area is connected in an air-conveying connection to an environment surrounding the pressure relief valve by at least one passage.
10 . The crusher of claim 8 , wherein:
the low-pressure area is connected hydraulically to a piston rod chamber of the hydraulic cylinder.
11 . The crusher of claim 1 , wherein the pressure relief valve further comprises:
a housing having an inner cylinder wall and at least one outflow opening, the at least one outflow opening being covered by the pressure relief piston in the closed position, and the at least one outflow opening being at least partially uncovered in the open position; and
wherein the at least one outflow opening is connected to a tank and/or to a piston rod chamber of the hydraulic cylinder.
12 . The crusher of claim 1 , wherein the pressure relief valve further comprises:
a bridging device including at least one pressure surface section delimiting the pressure chamber transversely to the actuating direction of the pressure relief piston; and
a projection of the at least one piston pressure surface of the pressure relief piston in the actuating direction covers at least 5% and at most 80% of a total of the projection of the at least one piston pressure surface of the pressure relief piston in the actuating direction plus a projection of the at least one pressure surface section of the bridging device in the actuating direction.
13 . The crusher of claim 1 , wherein the pressure relief valve further comprises:
a bridging device including at least one pressure surface section delimiting the pressure chamber transversely to the actuating direction of the pressure relief piston; and
a projection of the at least one piston pressure surface of the pressure relief piston in the actuating direction covers at least 10% and at most 50% of a total of the projection of the at least one piston pressure surface of the pressure relief piston in the actuating direction plus a projection of the at least one pressure surface section of the bridging device in the actuating direction.
14 . The crusher of claim 1 , wherein:
the at least one piston pressure surface has an area a maximum of 25% of a total surface area of the pressure relief piston exposed to the pressure chamber.
15 . A method of operating the crusher of claim 1 , comprising:
moving the pressure relief piston to the open position when a pressure threshold value in the pressure space of the hydraulic cylinder is exceeded; and
returning the pressure relief piston to the closed position with a spring when a pressure in the pressure chamber falls below a relief pressure.