Pacific Scientific Company

Particle Sizing Systems, Inc.

David Wells

David F Nicoli

An optical sensor for counting and sizing particles, including a light extinction (LE) signal representative of the particles, and a light scattering (LS) signal representative of the particles. The light scattering signal and the light extinction signal are combined to form a single composite signal. The single composite signal has a substantially similar output to the light extinction (LE) signal for particle sizes in an upper range of particle sizes typically measured by the light extinction sensor. The single composite signal has a substantially similar output to the light scattering (LS) signal for particle sizes in a lower range of particle sizes typically measured by the light scattering sensor. The single composite signal has an output representing the combined light extinction (LE) signal and light scattering (LS) signal for particle sizes in a middle range of particle sizes.

Single-particle optical sensor with improved sensitivity and dynamic

In a particle measuring instrument for measuring particles entrained in liquids, a gear pump located downstream from the flow cell of the particle measuring instrument is used to maintain a constant rate of flow through the flow cell. When the source of liquid is at a high pressure, a pressure regulator and a check valve are used to maintain the pressures at the inlet and outlet sides of the gear pump, respectively, at predetermined pressure values to maintain a predetermined pressure differential across the gear pump. When the source of liquid to be measured is at ambient pressure, the outlet of the gear pump is connected to ambient pressure and the gear pump draws liquid through the flow cell causing the pressure at the inlet side of the gear pump to drop the predetermined pressure differential below ambient pressure.

Particle measuring system with pump adapted to maintain constant flow

A particle measuring and counting system employs an isokinetic diluter comprising a gas filter having a capillary tube extending through the middle of the filter. The capillary tube and filter are arranged to divide a stream entering the filter into an outer substream from which entrained particles are filtered and an inner substream containing a sample of the outer substream. The two substreams are mixed downstream of the capillary tube and the resulting diluted sample flows through the particle counting and measuring instrument.

Isokinetic diluter for particle measuring instrument

In a system for measuring minute concentrations of dissolved solids in liquids, seed particles of a known diameter are mixed with the liquid and the mixture of the seed particles and the liquid is atomized into droplets of a known size. The droplets are dried to residue particles comprising the seed particle surrounded by a shell of the dissolved solid. The size of the residue particles are measured by passing the residue particles through a laser beam to scatter light to photodetectors so as to generate a pulse from each particle. The amplitude of the pulses will indicate the size of the residue particle from which the thickness of the shell and the concentration of the dissolved solid can be determined.

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Silver Spring, MD, United States of America

David Wells