Hydraulic Shredder

Hydraulic Shredder is one option of the configured shredder drive options. Wiscon Envirotech offers 3 alternatives and they are standard motor drive, VFD (variable frequency drive) and hydraulic drive. Hydraulic drives can be applied to all kinds of one shaft shredders and two shaft shredders. The higher power, the better.

The waste Shredder shall include the following components:

• Rotary Shear, cutting table with two rotors, cutting table;
• Ram Feeder with ejection door;
• Upper Hopper;
• Structural steel support frame;
• Interlock Chamber;
• Discharge Hopper;
• Fire Door;
• Hydraulic Power Pack;
• Air Cooler;
• Electrical Cabinet,
• Programmable Logic Controller (PLC) and Human Machine Interface (HMI).

It should consist of the three main components that Shredding Table, Hydraulic Power System and Control System.

Benefits of hydraulic shredder

• It is easy to control and accurate. Because, a system operator can easily start, stop, accelerate and slow down
• Hydraulic units are simpler in design and more durable as they use less moving parts.
• Can deliver constant torque or force regardless of speed changes.

As we know transmitting desired torque is essential in shredding process, a shredder with hydraulic drive is a perfect match.

Shredding Table

The main component of the hydraulic shredder frame should be of a complete machined body and durable. The critical sub-component that is exposed to wear and tear should be secured and protected by replaceable plate. Thus allowing for ease of dismantling and replacement to reduce maintenance cost.

All the contact surfaces of all critical components should be sealed to ensure a high protection against leakages when liquids are introduced to the Shredder unit.

The hydraulic shredder should be designed with the following guidelines:

• Capable to handle different kinds of wastes
• High productive rate for continual daily operation up to 90% of the operation
• Rotors reversed in direction to clear the jam or stall.
• Prolonged lifetime of cutting
• Replaceable and independently exchangeable consumable components.
• Equipped with ejection door for removal of non shreddable
• Hydraulic displacement for maintenance
• Direct hydraulic drive and automated control.

Shredder with Hydraulic Pusher

Shredding Capacity

The waste to be shredded is hazardous waste/industrial waste/bulk waste and maximum shredding capacity to be 17 cycles/hr with N2 blanketing.

It should be designed for regular feeding into feeding hopper for maximum operating conditions and various waste density taken into consideration and able to shred many kinds of waste (IBC tank, Drums, bulky waste). The expected size reduction should be 90%<250mm or less.

Driven by hydraulics they are modular and robust, offering performance advantages (speed and power) at the same time.

The acceptable noise level should be in the range of <85 dB (A) at 1 m( unloaded) and approx. 90 dB (A) if loaded or equipped with hydraulic unit complete with oil / air cooler. Supplier should aim to have a lower noise emission.

The shredding cutting elements should be designed with 2 cutter rings with teeth that rotate in opposite directions and 2 different rotation speed. In order to prevent overloading, the rotation direction should be immediately reversed for a few seconds if hydraulic pressure reach 330Bar and thereafter resume to its initial direction.

The shredder with hydraulic drive should include for minimizing dust emanation, heating up of the particle and eliminate the likelihood of explosion risk during shredding activity.

Shredder Construction

The Hydraulic Shredder frame should be designed to consist of two parts (lower and upper) that can be disassembled easily and enabling ease of rotors removable. Additionally, all parts in contact with the waste can be easily and independently unscrewed and exchanged according to needs. The frame should be designed not to be in direct contact with any of the waste to prolong the lifespan.

The rotors should be designed to consist of 2 shafts, equipped with cutter rings, distance rings, roller bearings and a sealing system. The shafts are to be made of alloyed forged steel and heat treated.

The cutter rings are of forged CrNiMo steel and are entirely machined (milled and grinded), heat treated and surface hardened. It should be able to be rewelded and grinding several times after prolonged wear and increase lifespan.

The hardened surface should guarantee an excellent resistance against abrasion. The heat treatment prior to surface hardening should guarantee a good resistance and tenacity of the core.

The roller bearing on both ends of the shaft are to be designed with protective sleeve and allow quick ease of exchange during maintenance. The sealing system between the cutting chamber and the roller bearings is to ensure full secure.

The bearing housing frame carries the sleeves for the roller bearings. They are composed of two parts screwed one to the other thus facilitating dismantling and remounting of the complete shaft. Screwed wear plates protect the frame and improve the tightness of the system.

The rotor in the rotary shear is driven by a low speed hydraulic motor with long lifespan thus allowing it to reach the maximum torque in the minimum of space. The hydraulic motor is fixed on a torque arm and linked to the shredder body by a shock absorber. The shock absorber protects the mechanical and hydraulic parts against overloads and shocks during shredding. The motors are driven by the hydraulic power pack.

The number of reversals on the shaft rotation before the object if detected as non shreddable to be set between 2 to 5 times. When the number of expected reversals of rotation has been reached by the shredder, the machine is stopped and an alarm is transmitted to the operator by suitable means to be designed.

industrial shredder with hydraulic pack

Hydraulic Power System

The Hydraulic Power System to be designed for installation at dry, ventilated and tempered room beside the shredder and the electrical cabinet. It should consist of the framework, a steel tank and an electrical motor pump.

For the closed high pressure loops it should be designed to be driven by a hydraulic motor. with each loop consists of an electric motor driving a self-adjusting volume pump whose volume is automatically adjustable.

For the open low pressure loops it should be designed with a feeding pump integrated in each main pump to provide clean and fresh oil to the closed loop and cooling unit. Each pump outlet should be connected to a filter before entering the high-pressure circuit. For the open loop at middle pressure, it should be used for any auxiliary function of the shredder (jack etc.).

For the return loop, the oil returns directly to the tanks after cleaning the carters of the hydraulic motor and the main pump. Two other oil throughputs arrive in the exchanging bloc of the main pump. They are put together, cooled if needed and filtered before going back in the tank.

The hydraulic pumps should be designed with a hydraulic power regulator with short reaction time and automatically adjust the pump size according to the waste product to be shred and ensures that only the necessary power (kW) will be drawn from the electrical motors.

The high oil exchange rate resulting from the oversized feeding pump improves oil filtering and cooling. It also ensures a low temperature gradient between the main loops and the oil tank.

A water-cooler to be designed and installed to allow proper input water to avoid plugs in the cooler.

Wiscon Envirotech provides the internal piping of the hydraulic power pack, and the flexible/rigid hydraulic pipes between the hydraulic power pack and the shredder for dimensions mentioned in the supply.

The hydraulic power system should be designed using the following guidelines:

• The ambient temperature necessary for a proper functioning of the system must be between -10°C and +40°C.

• Total weight, full (incl. electrical cabinet) about 5 t Capacity of the tank approx. 600l
• Rotation speed 1’480 rpm
• Total installed power 200kW
• Voltage 400 / 690 V, 50 Hz insulation class F
• Class of protection IP 54
• Pump variable displacement, closed loops
• Volume and flow rate of main pumps 2×250 cm³, ± 375 l/ min
• Pressure 160 / 320 / 380 bar (instantaneous)
• Number of filters 3, with clogging switch
• Type of oil cooler oil/water or oil/air

Hydraulical Shredder

Control System

Wiscon Envirotech designs the electrical cabinet fixed to the frame of the hydraulic power pack, and the cabling between those two elements and should be installed in a dry, ventilated and tempered room located near the two shaft Shredder.

The Control System should be designed to be allowed operator to control, monitor and receive signals to and from the control room. There should be a local control panel installed near the double shaft shredder for manual operation overrides and EMERGENCY STOP if there is an emergency.

The electrical cabinets in should be designed with the following guidelines:

• 1 main circuit breaker, with outside handle which can be locked with a padlock
• Star-delta starters and protection fuse for motors whose power exceeds 37 kW
• Protection of control circuits
• Transformers for control circuits with voltage less than 400 V
• Siemens PLC controlling all functions (except the emergency stop).
• Emergency stop circuit hardwired with safety relays
• Lighting, ventilation and temperature maintaining

The Control System should be designed with the said guidelines:

Voltage for:

• power supply circuit 200 / 690 V – 50-60 Hz
• command circuit 230 VAC – 50 Hz
• microprocessor 24 VDC Protection class IP 54

Greasing System (Optional)

Wiscon Envirotech design the Shredder with a centralized greasing system. This system mainly consists of a manual pump (foot activated) with a 5L dosage tank and a central distribution unit equipped with valves and manometer directing the grease into the different points to lubricate.

Hydraulic Feeder Ram

Wiscon Envitotech designs and supplies a feeder ram that sturdy welded steel construction reinforced by profiled steel sections in order to guarantee a good stiffness. It should be secured to the machine. All components which are exposed to high wear are equipped with screwed wear plates with ease of accessibility and exchange.The inclined position of the ram feeder and the tight housing to prevent leakage of liquids. The ram feeder should be driven by a hydraulic jack powered by an auxiliary pump of the hydraulic power pack. The feeding can take place at every moment, independently of the position of the ram feeder.

The position of the ram feeder is controlled by limit switches. All the elements of control (limit switches, pressure on the hydraulic power pack, etc.) should be PLC-controlled and analysed. The control and command of the ram feeder take into account the real charge of the rotary shear at the very moment, in order to maximise output of the installation.

A hydraulic operated door is integrated in the feeding hopper and offers accessibility to the cutter rings of the shredder as well as a simplified way to extract non shreddable objects dropped into the machine.

How to Select a Right Industrial Shredder Machine