Geberit Group

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  • Geberit Group

Optimal flow

Mon­day morn­ing in a 20-storey res­i­den­tial build­ing. It’s all go in vir­tu­ally all the bath­rooms, mean­ing that it is also “rush hour” for the build­ing’s waste water dis­charge stack. Using high-per­for­mance com­put­ers, Geberit sim­u­lates what is hap­pen­ing in­side the stack from a fluid dy­nam­ics per­spec­tive. Se­lect the dis­charge stack and con­nect to the toi­let. Click on the flush but­ton to see the cor­re­spond­ing flow sim­u­la­tion.

Pushing the limits of what is possible

All drainage sys­tems from Geberit are noted for their ex­cel­lent flow be­hav­iour. This is in no small part down to the great work car­ried out by the flow spe­cial­ists – the ex­perts who op­ti­mise vir­tual prod­ucts on their high-per­for­mance com­put­ers until the cor­rect per­for­mance pro­files are achieved.

Geberit uses com­puter sim­u­la­tions to de­ter­mine and op­ti­mise the flow be­hav­iour of san­i­tary com­po­nents, long be­fore the first pro­to­types are made. Doing so en­ables time and money to be saved dur­ing prod­uct de­vel­op­ment while also al­low­ing so­lu­tion ap­proaches to be pur­sued that would be vir­tu­ally un­think­able with­out vir­tual en­gi­neer­ing.

An old trick

This can be illustrated in greater detail using the Geberit Sovent fitting as an example. This fitting is used in high-rises to connect the discharge pipes from an individual floor to the discharge stack. As part of the product optimisation process, the aim was to increase the product’s discharge rate. The key questions here were: What is the highest possible flow rate in theory and to what extent can this value also be achieved in practice? An everyday trick put the flow specialists on the right track. If you want to empty a full water bottle as quickly as possible, you hold it with the opening facing downwards and rotate it gently. This makes the water swirl, enabling an air column to form in the middle of the opening. This air column ensures pressure compensation, which enables the water to drain out of the bottle at a much faster rate.

Major improvement in performance

Inspired by this physical phenomenon, the engineers set to work at their computers and added an asymmetrical kink in the upper section of the virtual Sovent fitting. This caused the – also virtual – water flowing down to rotate just like the engineers had envisaged, creating a continuous column of air in the centre. Initial calculations showed that this design modification had significantly accelerated the flow rate of the water.

After the completion of the simulation work on the computer, the first prototypes were made and tested under realistic conditions in the 24-metre-high waste water tower. The results were clear: Installing Sovent fittings that had been optimised from a fluid dynamics perspective increased the discharge capacity of a discharge stack by 40 per cent.