Mechanical Hook Screen

Screens are manufactured from stainless steel AISI 304 or AISI 316 on customer demand. The movable and endless filtering mesh consists of hooks and is installed on the screen frame. Filtering mesh openings are 5mm wide by default, but can be adjusted on customer demand. The rectangular frame consists of two longitudinal boards connected by crossbeams. The filtering mesh moves along polymer guides installed on the longitudinal boards of the screen, and is driven by a shaft with drive sprockets located on the top part of the screen.

The shaft is driven by a geared motor. Filtering mesh tension can be adjusted. Wash water nozzles and a drum with radially located brushes are placed on the driven shaft of the geared motor. This motor is installed on top of the screen frame and is designated for the filtering mesh hooks cleaning.

Operating Principle

• The hook type screen retains and removes solids of which the size exceeds that of the filtering mesh openings from the wastewater. Collected solids are moved in an upward direction to the discharge zone by means of the hooks. Here it is discharged into the transporter or waste bin. After the waste is discharged, cleaning of the filtering mesh is performed by wash water from the nozzles, followed by the revolving brushes. In addition, the previous hook line cleans the next hook line at the moment of its overturn.
• The screen operation periodicity depends on the equipment automation scheme.
• Due to the special design of the filtering mesh, a contamination layer is generated onto the working surface and creates an additional filtering effect which allows catchment of particles with sizes less than 5 mm.

Automation

• Screen automation can be done according to different parameters: Wastewater level difference upstream and downstream of the screen.
• Any customized program.
• 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.
• The screen is supplied with safety device to avoid damage to any screen components.

The safety device stops the screen operation when bulky waste ingress the filtering mesh, or when any other object blocks free plate movement. Light and sound alarms turn on simultaneously when the safety device is active. The screens, together with a conveyor, compacting press and slide gates, are included in a high-performance complex for mechanical wastewater treatment.

Equipping the control system with programmable modules makes it possible to integrate complex sub systems into one system with a common control center and remote dispatching.

Advantages

• Fine mechanical wastewater treatment is achieved due to the narrow filtering mesh spacing, as well as the contaminants layer formation on the screen’s steps Special design of the hooks makes the filtering mesh self-cleaning.
• Reliable and easily operated
• Step screen is manufactured from stainless steel AISI304 or AISI316 (on customers demand) which makes the equipment corrosion resistant