| 摘要 |
<p>A fluid diluter consists of a hydrodynamic focusing device (23) having a circular mixing chamber (28) opening into a receiving chamber (32) via a sensing aperture (30). Diluent is supplied from a source (37) and mixed with a sample (24) of blood, for example, and the sensing aperture (30) counts the presence of particles such as haemoglobin in the sample using the Impedance method. The receiving chamber (32) is subsequently emptied and the cycle repeated. In one embodiment, through-flow is achieved via a pair of pumps (17, 19) having different pumping capacities, connected together with a common piston assembly (16, 18). In a second embodiment, four pumps (17, 19, 68, 70) are employed, three of which (17, 68, 70) are ganged together. Such a system is substantially less bulky than known diluters yet permits accurate attainment of high dilution ratios (e.g. 6000:1). Particles may thus be analysed in the aperture (30) one at a time without 'coincidence'. Altering the relative capacities of the pumps permits adjustment of the dilution ratio.</p> |
