Ludemann Strainers: Ingeniously simple – simply ingenious!

Most malfunctions and system failures that come about in steam traps, pressure regulators and in a variety of control and measuring devices are due to the lack of an appropriate strainer able to prevent the soiling that is caused by sand, rust, etc.

Our strainers protect against such deposits and thus safeguard both your investments and the productivity of your plants.

Ludemann strainers are – thanks to varied manufacturing materials and special coatings – suitable for a wide range of uses, e.g., for water, oil, compressed air and steam. They can be incorporated into pipes horizontally or vertically. It is advisable to have shut-off valves built in on either side of the strainer in order to be able to clean the filter simply (i.e. without having to completely empty the system) and as necessary.

The medium flows through the strainer and through a screen with a large surface area. The cleansing capacity of this filter depends on the mesh number selected. During this process, dirt particles are caught and collected in the filter. The dirt particles deposited can then be easily removed when the filter is cleaned (regular cleaning required). The filters are otherwise practically maintenance-free and do not require special operation or the like.

Customised protection for your industrial and commercial plants

Our strainers provide industrial and commercial plants with long-term protection against the malfunctions that arise as a result of foreign matter being flushed into the system. This considerably increases the longevity of the plants and, in turn, also safeguards your investments.

We can assist you in selecting the strainer that best suits your needs, and are happy to put our experience and expertise at your disposal.

Our delivery programme is specifically designed to meet the requirements of the following sectors:

  • Chemical / Petrochemical
  • Power plant technology / power plants / nuclear power plants
  • Food industry
  • Marine applications
  • Oil and gas industry
  • Paper and cellulose industry
  • Pharmacy
  • Steel industry
  • Low-temperature applications
  • Drinking water and waste water plants,
  • Environmental technology

Thanks to the continual expansion of our range and the effective development of our products, our ability to react to the individual demands of the industry will continue into the future. We can thus ensure the long-term full functionality of your plants.

Chemicals / petrochemicals
Power plant technology / heat & power plants / nuclear power stations
Foodstuffs industry
Marine applications
Oil and gas industry
Pulp and paper industry
Steel industry
Low-temperature applications
Drinking water and waste water management
Environmental technology

Simple to install, straightforward to maintain

Operating pressures in line with DIN 2401 for liquids, gases and vapours

We make express reference to the restrictions applying to materials pursuant to DIN 2401, sheet 2, page 3.
Cast iron strainer are not approved for use in equipment according to TRD 110.

PN Permissible operating pressure in bar at temperature specified in °C
120 200 250 300 350 400 425 450 475 500 510 520 530 540 550
PN 6 6 5 4,5 3,6                      
PN 10 10 8 7 6                      
PN 16 16 13 11 10                      
PN 25 25 22 20 17 16 13                  
PN 40       40 38 36 35 34 33 29 24 19 15    
PN 63       63 61 58 57 56 53 47 40 32 25    
PN 100       100 95 91 89 87 82 74 62 49 38    
PN 160       160 153 146 142 139 132 118 100 79 62 46 35

Material tests

Certificates of compliance, inspection certificates and approval certificates can, if required, be requested upon issuing the order. The additional costs that this incurs will be invoiced.

Fitting / installation

The strainers are fitted with the screen basket filters facing downwards in the direction of the flow (see arrow on the device casing).

We recommend that shut-off valves are fitted on either side of the strainer in order to be able to clean the filter without having to completely empty the system. Strainers with fine mesh screens (double screen) are marked with a red dot on the plug or flange cover.

If you need to integrate a strainer into a suction line, please enquire about our special models.

Maintenance / screen cleaning

The screen is to be cleaned at regular intervals depending on the level of soiling caused by the respective medium. The strainers require no further maintenance.

Step 1: Shutting off the system

Whenever maintenance and cleaning measures are being carried out, the shut-off devices at the front and back of the strainer must be closed. This is to prevent the continued flow of the medium and to establish a pressure-free environment.

Step 2: Emptying the strainer

Caution: In order to carry out this work, the system must be entirely pressure-free!

Loosen the flat head cover with a suitable instrument. Carefully screw out the flat head cover and have a suitable container at the ready in order to catch any liquid that escapes.

Step 3: Removing flange cover

Loosen the bolts on the flange cover with a suitable instrument. Please take care to loosen and to screw out the nuts in a crosswise manner in order to prevent the cover from tilting.

Once all the nuts have been removed from the screws, you can remove the cover from underneath. Here too, you will need to have a suitable container at the ready in order to catch any remaining fluids.

Step 4: Removing the screen

Once the cover has been removed and the residual liquid has come out, you can remove the screen by also pulling it out from under the strainer.

Step 5: Cleaning screen and checking for damage

Depending on the medium, remove the dirt and deposits using water, a special cleaning liquid or a brush. In doing so, please adhere to your company regulations with regard to environmental protection and safety!

Following the cleaning procedure, check the screen for any damage.
Should you discover holes or other damage in the screen, then you will need to replace the screen! Only faultless screens can be re-fitted following cleaning.

Step 6: Fitting the screen

Carefully slot the screen back into the strainer from below.

Remove the cover seal from the cover in order to visually check it before fitting.

Step 7: Checking and fitting cover seal

Should the cover seal show any signs of damage, then it must be replaced. Only an entirely defect-free cover seal can guarantee that the strainer is reliably sealed.

If the cover seal is undamaged, then refit the respective nut in the strainer – not the cover!

Step 8: Fitting and screwing flange cover tight

Place the flange cover back onto the strainer and screw the nuts crosswise onto the screw thread. Finally, screw the nuts (crosswise) using the torque prescribed (50 Nm).

Make sure to remember to properly replace the flat head cover onto the lid!

Step 9: Commissioning the system

Following successful completion of cleaning / maintenance measures, you can restart your system by slowly opening the shut-off valves.