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SMH Products Ltd

Pumped filter system for a City Hospital

In November 2015, a contractor delivering work on behalf of a City Hospital approached SMH to design and develop a bespoke pumped filter system to remove and filter with asbestos-contaminated water.


The challenge

The contractor was to undertake work at a City Hospital to seal up two service tracks which, when it rained, filled up with rainwater. The tracks were insulated with an asbestos-containing material, which contaminated the rainwater. The contaminated water needed to be pumped out of the tracks and filtered to allow it to be safely drained away.

The system had to be able to pump water from a basement to ground level, i.e. up to 7m, and capable of pumping water at a rate of 120l/min to clear the volume of water in a reasonable amount of time.


The solution

In consultation with the customer, we developed a two step pumped filter system to fully meet their needs. This consisted of a sump box containing the sump pump (with a large particulate strainer) and float switch to be fixed in the basement. The lightweight but robust pump – only 7kg – could be easily located but had the performance required: 

  • A flow rate of up to 140 l/min, achieved by a powerful 230v motor which can easily handle the small solids found in suspension in the contaminated water
  • A head (lift height) of up to 7m to ensure the flooded basement could be cleared easily

The sump box was then connected to a bespoke surface located filtering system. This system has three stages of filtration to deliver full and efficient decontamination of the water:

  • 2 x 100µ pre-filters in parallel for removing large particulate
  • 2 x 50µ filters in parallel
  • 2 x 5µ wound 20" cartridge filters in parallel

The controls for the full system (sump pump and filter system) were housed in the filter unit to allow operation without needing to enter the contaminated area. The unit had a built-in frost protection system, essential for equipment that was to be sited outdoors during winter, and all control equipment was separated from the filtration system in an IP rated polypropylene enclosure. 


The result

The unit was built and tested at SMH’s manufacturing site before being shipped to the site. With a straightforward control panel and simple set-up, the unit was put to use immediately.


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