Huntleigh AlphaBed, Service Manual

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2 Technical Description
The pressure regulated pump units listed in section 1 provide pressurised air for alternating pressure
mattress systems which are used in aiding the prevention, treatment and management of pressure
ulcers.
Pressurised air is fed to a range of support systems, mattresses, seat cushions etc., which support
patients at risk of developing pressure ulcers.
All pumps are self-contained units powered by the single phase mains/power supply. Low air
pressure and power failure alarm functions are included in some models, and pump output pressure
is adjustable by means of a rotary control mounted on the unit front panel.
Operating Principle
Refer to Figure 1 for details of the pneumatic circuit. All pumps have two pressurised air outlets, air
from the outlets is fed to separate cells or groups of cells in the mattress or cushion via a rotary valve.
The support cells are continuously inflated and deflated utilising a ten minute cycle. During the cycle,
air is pumped from one outlet for 4 minutes 10 seconds, there is then a period of 50 seconds where
air is pumped from both outlets. Air is then pumped from the other outlet for 4 minutes 10 seconds,
followed by a 50 second period where air is supplied from both outlets. During the period when air is
suppled from a single outlet to one group of cells, the opposing outlet is vented to atmosphere,
deflating the corresponding cells.
Issue 2 Chap 1
Nov 2001 SER0004 Page 3
Mini Pump Service Manual Introduction