Grinding Screens and Waste Grinders

Cutters and shafts of the screens are manufactured from high tensile tool steel, while the frame is manufactured from stainless steel AISI 304. The screen consist of two sets of rotating cutters located vertical on drive shafts enclosed in the frame. Rotating filter drums can be installed on one or both sides of the grinding unit depending on the channel width. The cutters and drums are driven by geared motors. Auxiliary fixing devices allow lifting of the screen from the channel without emptying it, therefore maintenance can be carried out without stopping operation. The grinding mechanism and filtering drum are installed as separate units and can be removed from the device without lifting the grinding screen.

Operating Principle

From the rotation of the perforated drums, the solids are moved to the grinding unit where the cutters grind the waste and direct it further along the channel. The cutters rotate at different speeds to create the shear effect.

Advantages

• Protects downstream equipment by reducing the size of solids suspended in the wastewater.
• Reduction of service personnel demand of the pumping stations and costs on waste disposal.
• High screen productivity and reliable performance due to the design of the drums which prevent waste build up inside the screen.
• High serviceability due to the screen design – easy mounting and dismounting.
• Automatic protection against jamming with reverse and restart of the grinding cutters

Automation

• Screen automation can be done according to different parameters:
• Time period.
• Wastewater level difference upstream and downstream of the screen.
• Any customized program.
• The screen’s automatic safety is achieved by a short reverse cycle of the cutters to prevent jamming by solid waste.
• Alarm systems of the normal operation indication, the emergency stops, the wastewater top level in the channel and others are provided. It is possible to transfer equipment status data to a higher level automated process control system depending on the client’s requirements.

Cutters and shafts are manufactured from tool steel, while all other parts are manufactured from stainless steel AISI 304.z The grinder consists of two sets of rotating cutters that are installed horizontally and enclosed in the frame. A loading hopper is provided on the top of the frame for waste feeding from the screening equipment to the grinder. The gravity slide located at the bottom of the frame directs grinded waste to the wastewater channel after the screening equipment. The grinder is mounted onto a prop which is fastened to the ground at both sides of the channel. Cutter shafts are driven by a geared motor.

Operating Principle

Waste from the mechanical screening equipment is directed to the loading hopper of the waste grinder via the gravity slide. The waste is grinded by counter-rotating cutters and dispatched further along gravity slide.

Advantages

• Reduces pumping station service personnel and costs for waste removal from pumping stations.
• Retention of organic compounds in the wastewater for further biological treatment processes.
• Automatic equipment protection prevents jamming and congestion – grinding cutters reverse and restart.

Automation

• Using the grinders allows the customer to operate the pumping stations in a fully automated mode. The grinder automatically switches on when the sewer mechanized screen switches on. Other automation options are also available.
• Alarm systems of the normal operation indication and the emergency stops are provided. It is possible to transfer equipment status data to a higher level automated process control system depending on the client’s requirements.