摘要 |
Liquid chromatograph apparatus comprises a plurality of solvent sources (104,105) feeding a pump (102) via a proportioning valve arrangement (100). The proportioning valve arrangement (100) has a plurality of inlets (108,109) and a single outlet (110) which is coupled to the inlet coupling (112) of the pump (102). The inlet coupling (112) is mounted directly on the pump head (103) and incorporates a filter (118, Figure 3). The pump outlet (137) is fed via a tube (138) to a chromatographic separating column. The solvent sources (104,105) are coupled to the proportioning valve inlets (108,109) via tubes (106,107) without the provision of separate filters. This gives more equal average flow rates and enables more accurate proportioning of the solvent mixture to be obtained. |