| 摘要 |
<p>1457922 Salt bridge leak INSTRUMENTATION LABORATORY Inc 4 April 1974 [13 April 1973 20 Dec 1973] 15081/74 Heading G1N A salt bridge leak comprises two juxtaposed openings 60, 86, a guide structure 70 which establishes straight line motion of one opening (86) and biases it towards the other and a flow control member 64 disposed between the openings where it is clamped without shear forces. The flow control member can preferably be moved longitudinally to place a new section between the openings. As described the salt bridge leak connects saturated KC1 46 contacting a calomel electrode 44 with blood flowing into tube 24 and contacting a glass electrode 20 with silver/silver chloride reference 16. Blood, the pH of which is being measured, flows through tube 24, pH sensitive glass 20, passages 30, 34 and 36 and valve 38 under suction from pump 40. At the junction of tubes 30 and 34 (at an angle of 120 degrees) is a 1mm diameter opening 60 situated in groove 62. The flow control member 64 is located in the groove and comprises a 10 micron thick strip of hydrophilic polycarbonate with a plurality (3 x 10<SP>8</SP> per sq. cm) of 0À1 micron diameter pores. The strip is wound between reels 66, 68 which fit in recesses 74, 76 and can be wound on by spindle 80 from wheel 78. The saturated KC1 solution from the reference electrode is supplied via valve 50 to tube 52 which can move linearly in housing 70 and the end 86 of which is biased into contact with the flow control member 64 by spring 88. The flow control member 64 is kept clean by flushing passages 30, 34 between blood samples, but a new portion can be selected by operation of lever 90 to move tube 52 out of contact with the flow control member and rotation of wheel 78.</p> |
