GB1471527A - On-line system for monitoring particles in fluids - Google Patents

Abstract

1471527 Monitoring particle suspensions COULTER ELECTRONICS Ltd 7 June 1974 [14 June 1973] 28350/73 Heading G1N [Also in Division F2] In the on-line testing of a flow of a fluid particle suspension using a Coulter type analyzing apparatus the flow of fluid is maintained constant. Filtered sea water to be tested flowing along pipe 12 is sampled by tube 16 connected by flow restrictor 20 to a flow-through sampling chamber 42 in which are mounted apertured tubes 26, 28, 30 and associated electrodes 44 and 32, 34, 36 for monitoring the particle sizes. To make the differential pressure at each aperture 26a, 28a, 30a constant to ensure the same volume of fluid passing through the apertures in a predetermined time a regulator 56 is coupled to the chamber 42 which comprises two hollow members 62, 64. Member 64 of greater cross-section train member 62 is filled with mercury whereas member 62 is filled with the less dense test fluid. Initially with low or atmospheric pressure in member 62 the mercury falls to the base of the U-tube with the two surfaces at the same level. If now the pressure in member 62 increases, due to an increase in pressure in chamber 42 the mercury column is driven up into member 64 until a point is reached where the boundary surface of the mercury and test fluid is at 66. Any further increase of pressure of the test fluid does not cause the base of the mercury column to rise but causes the test fluid to breath through the lower boundary surface and rise through the mercury column to relieve the pressure of the test fluid. Thus the pressure within chamber 42 remains constant. A U-tube manometer 73 may be provided to indicate the pressure due to the head of mercury in regulator 56. If the pressure within the main pipe 12 falls below a minimum pressure a pump 76 can be provided to produce the pressure. Particle analyzer. Debris detecting and clearing circuit 82 of the type described in Specification 1061776 may be used. If a blockage occurs in one of the aperture tubes a signal is fed to control apparatus 52 to initiate a debris clearing procedure e.g. by pinching conduit 46 to create a back pressure at the aperture of the tube. If this is unseccessful the tube is disengaged and another tube is used instead. When blockage occurs circuit 82 applies an inhibit signal to line 85 to inhibit pulses from being registered in output 86. This latter may have a pre-setable pulse count value stored in it such that if this is exceeded alarm 88 is actuated.