Screen Cleaning Machines (Trash Rack Cleaners)

Screening losses have a major impact on efficiency in water and waste-water treatment, and accumulated screening deposits need to be removed on a regular basis. We have developed specialised Screen Cleaning Machines with trolleys and grabs to fill the bill in every area.

Water scoop and pumping stations, waste-water and sewage treatment facilities, hydroelectric power plants and dam and reservoir installations have been using screen-cleaning equipment from Apparatebau Münster since 1950. Over 1100 rigs are at work using the same tried and trusted principle - screenings are gathered in one fell swoop in front of the screen down to the bed, and transported directly to a dumpster or screening dump.


The trolley travels in a narrow path supported above the screen using beam and frame supports. The brake motor ensures precise movement of the trolley in either direction. There are two independent cable-slack detectors integrated into the two separate cable reels in the hoist, eliminating the need for rollers turning against the cables. The asymmetric grab consisting of a prong carrier with fixed prongs and a hydraulically controlled swivelling collecting basket is suspended on the two cables. A compact hydraulic motor in the trolley supplies the hydraulic fluid, and is connected to the actuators on the grab by a double hose.

How it works

  1. The trolley moves over the screen, the hoist motor is switched on and the grab is lowered.
  2. The grabber prongs slide between the screen elements. Limiters prevent the grab catching behind the cross-members in the screen.
  3. The descending grab collects the screenings from the water surface to the bed.
  4. Once the grab arrives at the bed, the grab closes and the hoist motor is switched on.
  5. Once it has reached its upper position, the hoist motor is switched off and the traction motor is switched on.
  6. The grab opens above the screenings dump to allow the screenings to fall. After that, the trolley travels back to the screen for cleaning to continue.


The following Screen Cleaning Machines are available:

R66 Screen Cleaning Machine

Our R66 Screen Cleaning Machine has the highest capacity. R66 rigs are often used in hydroelectric plants as well as large water and waste-water pumping facilities.


Working depths8,00m0 - 30,00 m
Grip width1860 mm1400 - 3500 mm
Grip weight630 kg500 - 1500 kg
Load capacity990 kg800 - 2000 kg
Actual load360 kg300 - 1500 kg
Carriage speed30 m/min0 - 60 m/min
Hoist speed19 m/min0 - 30 m/min
Hoist4,00 kWif necessary
Carriage1,10 kWif necessary
Hydraulic motor1,00 kWif necessary

R71 Screen Cleaning Machine

Our R71 models can be used in any application. R71 models are sued for cleaning screens in pumping stations, sewage-treatment plants, waste-water pumping stations, and for drinking, process and cooling water feed stations as well as in barrages.

We supply a range of options specifically intended for use in waste-water treatment in rough terrain:

  • Trolley equipped with a broad-gauge carriage for travel in the direction of flow
  • Carriage designs to reduce structural height
  • Explosion-protected designs
  • Stainless-steel designs



Working depths8,30 m0 - 14,50 m
Grip width1000 mm500 - 1400 mm
Grip weight430 kg300 - 550 kg
Load capacity700 kg500 - 900 kg
Actual load270 kg200 - 400 kg
Carriage speed30 m/min0 - 60 m/min
Hoist speed15 m/min0 - 24 m/min
Hoist2,20 kWif necessary
Carriage0,37 kWif necessary
Hydraulic motor1,10 kWif necessary

R74 Screen Cleaning Machine

Our R74 Screen Cleaning Machine is fitted with a grab from the R66, R71 or R03 series. The hoist and hydraulic motor are fitted into a horizontally swivelling arm, rather than in the trolley. The arm rotates from the screen to a screenings dump using an electric motor.

This Screen Cleaning Machine is suitable for screens to be cleaned in one swoop. The grab width needs to be adapted to the width of the screen.

To save space, several dumpsters can be placed along the arm’s path of rotation. The automatic control is fitted into the column, and the Screen Cleaning Machine is ready for deployment after connecting the feed cable.


Working depths7,70 m0 - 10,70 m
Grip width1000 mm800 - 1200 mm
Grip weight290 kg
Load capacity700 kg400 - 900 kg
Actual load210 kg
Turning speed0,57 U/min0 - 0,57 U/min
Turning anglemax. 270 °max. 270 °
Hoist speed15 m/min0 - 15 m/min
Hoist1,50 kWif necessary
Turning mechanism0,08 kW0,08 kW
Hydraulic motor0,55kWif necessary

R03 Screen Cleaning Machine


Like the R71, our R03 Screen Cleaning Machine can be used anywhere – whether on screens in pumping stations, sewage treatment, waste-water pumping facilities, or in drinking, factory and cooling water feed stations. The more lightweight construction and lower total capacity makes R03 more suitable for water and waste-water facilities at a lower scale, or where lower screening amounts are expected.


Working depth7,70 m0 - 10,70 m
Grip width1000 mm840 - 1200 mm
Grip weight290 kg250 - 300 kg
Load capacity500 kg0 - 500 kg
Actual load210 kg200 - 250 kg
Carriage speed20 m/min0 - 30 m/min
Hoist speed15 m/min0 - 15 m/min
Hoist1,50 kWif necessary
Carriage0,37 kWif necessary
Hydraulic motor0,55 kWif necessary

How you benefit

  • Only one rig for screens of any width and number at varying depths
  • Rig can be altered to local conditions
  • No alterations to existing structures necessary, no structures interrupting the water course
  • Screen remains freely accessible; screen may also be manually cleaned by a rake if needed
  • Curved paths allow placement of screening dumpsters at any position
  • Screen is cleaned from top to bottom
  • Bulky screenings such as tree trunks, furniture, car tyres, or barrels are securely held by the grab
  • No underwater equipment installations

Design features

  • Tried and trusted design from more than sixty years of experience in constructing Screen Cleaning Machines
  • Grab prongs reach deep into the screen or through fine screens to release jammed screenings
  • High weight and specific centre of gravity in the grab ensure secure automatic operation
  • All surfaces on the grab that come into contact with the front edges of the screen elements are fitted with exchangeable sliding strips
  • Quality corrosion protection - not only all of the steel components, but also cable and hose reels as well as bearing casings are hot-dip galvanised; The trolley is protected from the weather by stainless-steel sheet; actuator piston rod and pivot bearing are in non-rusting steel
  • Motors and components from branded quality worldwide manufacturers
  • Insensitive to freezing and ice drift
  • Fitting two trolleys with grabs in one path doubles cleaning performance and increases safety
  • PLC for automatic operation
  • Rig can be activated at the press of a button, or triggered by a time relay, differential water-level switch, or external signal
  • Radio remote control or switch stick for manual operation