摘要 |
A dispensing device comprising a reservoir (2) and a one way valve (6) through which material may only be conducted into the reservoir (2). Reservoir (2) comprises a piston (16), a cylinder device (10) capable of permitting expansion of the capacity of the reservoir as material is conducted into the reservoir, an electrical switch means (18) adapted to detect and terminate the expansion of reservoir (2) at a predetermined capacity value, means for exerting pressure (10,16) on material within reservoir (2) when the expansion of reservoir (2) has been terminated and a one way valve (20) set to permit flow of material from reservoir (2) via an exit port whilst the pressure on the material in reservoir (20) is not less than a predetermined value.
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