Functional Comparison of Screens

The functional comparison of HST-Screen, Screen with Electric Drive, and Screen with Perforated Sheet

Category HST - Screen Screen with Electric Drive Screen with Perforated Sheet
Drive A constant forward and reverse speed.

Symmetrical force transmission.

All drive parts can work underwater and require only a minor amount of maintenance. (eg oil level check and visual inspection for leaks)

Symmetrical force transmission into the construction via a synchronizing cylinder on the cleaning unit (rake), thus no twisting and no torsion!

The synchronizing cylinder is not pressured in both directions but only need to be pulled!

Only low material stress, no twist, no torsion.
Arranged above on the screen frame; As a result, asymmetrical force introduction into the construction, larger driving forces required, cleaning device thereby prone to twisting (torsion).

Drive with Electric Motor:
chain and gear on top of the frame.

Drive in hazardous area!
Ex-Protection: Ex-Protection-Measures required!​
Drive in hazardous area!
Ex-Protection: Ex-Protection-Measures required!​
Automatic cleaning of the screen bars Hydraulic Cylinders - Rake:
Synchronous cylinder, thus same forward and reverse speed, only small amounts of hydraulic oil required. The roof-shaped rake passes through the rake bars in the longitudinal direction and back and promotes the screenings from the longitudinal bars back into the channel.

Plastic sliding guides on the lower frame (no steel on steel); thus lower wear and lower susceptibility to interference.
Rinsing-effect: Friction of sand on steel and excessive abrasions of the screen frame is prevented!
Rollers in wastewater:
the rake runs on rollers, therefore from time to time manual cleaning and maintenance is required

The raking teeth fold during operation in the direction required in each case.
The folding mechanism is very vulnerable !
The screenings are not unhooked but scraped off during cleaning and partially get into the receiving water!

The extent of the long holes is much longer than with longitudinal bars so that more solid wastes are kept at the edges.
Screen surface Screen bars:
Cartridge-shaped, rounded rake bars with a smooth surface, cold-rolled; thus very good hydraulic flow characteristics
Rake surface:
Perforated sheets have less free passage area, with the same amount of water larger screen surface is required!
Operation / Control By default, the "on-board computer" SMART is used for control and communication (IPC with Spft-PLC, HydroDat®, other software). Target of the control: optimal, to the hydraullic conditions adapted operation. Thus, gentle handling of the machine and controlled set-up of a filter carpet depending on the water level! The control logistics takes into account the water levels, the processing speed and the general condition of the screen.

Monitoring and data acquisition:
The data acquisition, (remote) monitoring and documentation of the functions and operating states is carried out with the HydroDat® operating data acquisition and monitoring system with the "on-board computer" SMART. The access can be made via modem optionally (with web server via Internet) from any PC, there is no local telecontrol substation and data center required! In the event of a malfunction, the manufacturer can provide remote diagnostics to reduce the operating costs and intervene in the control to optimize the operation. Visualization of the operation in the building via WebCam, thus condition-oriented maintenance possible.

HST Screen Control
with the "on-board computer"

S = System-Control
M = Monitoring
A = Archive
R = Reporting
T = Telemetry
After flooding, drives, chains, gears etc. must be cleaned manually, so the maintenance is required!

Trough in the underwater:
in the closed trough located water does not drain off
Through slots greater potential that screenings caught at the edges. After prolonged operation according to the manufacturer no uniform cleaning and shearing guaranteed. Maintenance-cleaning by hand required!

Perforated sheet metal:

This results in the meat grinder effect !!! Screenings caught in the slits are scraped off during cleaning. Danger of freezing.