the introduction of air increases its volume to prevent propellant material particles from penetrating into the valve between the pump and the inflatable parts an air permeable wall is fitted in front of the valve application_number US 37954095 A description fig1 illustrates an air mattress having a conventional basic shape it comprises a head section and a lying section represents the head section represents the pump section 1 and the lying section the inflatable section 2 the pump section 1 has a lateral inlet opening 3 which is sealed by an externally fitted plug 4 the plug 4 can be of any conventional type for example with a thread or with a seating all it has to do is prevent the passage of air through the inlet opening 3 between the pump section 1 and the inflatable section 2 is accommodated a valve block 5 which in the exemplary embodiment is arranged in the strip which separates these sections from one another in an airtight manner the pump section 1 accommodates a propellant material 1a illustrated in fig1 propellant material is understood to mean a material which increases its volume on entry of air a preferred propellant material is an open cell synthetic foam.