| 摘要 |
986,978. Electric tests. TECHNICON INSTRUMENTS CORPORATION. May 4, 1962 [May 15, 1961; Feb. 23, 1962], No. 17137/62. Heading G1N. In a particle counter, samples of liquid with particles suspended therein are taken sequentially from different sources and are transmitted in a continuous stream to a cell providing a constricted flow path in which electrical conductivity changes in the liquid are measured. Samples are drawn from containers 20 into tube 26 by the action of pump 14. Simultaneously a gas, e.g. air, and a diluent, e.g. distilled water, are drawn through tubes 30, 32, the three streams joining at 34 and being mixed in coil 36. The result is a series of liquid segments, of sample and diluent, separated by air bubbles. The air bubbles are drawn off through tube 40, while the liquid passes through tube 44 to cell 16. The cell comprises an outer portion 46, including a chamber 56, and an inner portion 48 connected through tube 80 to pump 14. Inner portion 48 has a small hole 76 covered in operation by liquid in chamber 56, the level being maintained by outlet 70. A compressible bulb 68 is provided for initially adjusting the liquid level. Electrodes 84, 88 are provided on either side of orifice 76 and are connected to D.C. source 94, and, through amplifier 96 and threshold circuit 98 to rate counter 100. The output of the counter is compared with a reference in null-balancing circuit 102 and the output is applied to a recorder 92. Respective peaks 106 represent the particle count in respective samples. Specifications 817,070 and 834,635 are referred to. Reference has been directed by the Comptroller to Specification 722, 418. |
