Particle Sizing & Distribution

Patterson globes/circles : NG1
Original Porton globes/circles : NG2
Modified Porton globes/circles : NG12
British Standard globes/circles reticle : NG10
Fairs reticle : NG5

Graticules Optics now offer 20.4mm (Olympus), 24.5mm (Leica) and 25mm (Nikon, Meiji) diameter reticles at standard prices – no need to pay a premium price for a special size

Key Features

Eyepiece reticle with globes, circles and ruled grid for particle sizing and counting The reticle pattern consists of a central rectangle, subdivided into 9 smaller rectangles with a number of circles and dots (globes) along the top and bottom edges. Each circle is marked with the diameter in units, 250 units being the length of the large rectangle. Rectangle size is nominally 4.5mm x 2.025mm and circle/dot sizes in microns are nominally 450, 360, 270, 225, 180, 145, 110, 74, 37 and 18.

Key Features

Eyepiece reticle designed to satisfy requirements of BS3625/BS3260

Pattern comprises globes (dots) and circles of increasing size along the top and bottom edges of a divided rectangle. Designed for measuring particle size in the range 150 to 0.38 micron. Circles and globes have nominal sizes in microns of 560, 400, 280, 200, 149, 100 and 70. Circle 1 is defined as 1 unit.

Key Features

Eyepiece reticle with globes, circles and ruled grid for particle sizing and counting

This modified version of the Porton reticle now has the globes and circles inside the expanded rectangular grid section, for improved traverse analyses.

Key Features

The circle/dot areas and right-hand side rectangle divisions increase with Root 2 progression. All elements are numbered for reference. The rectangle is 4.5mm x 2.025. The specimen is racked on the stage of the microscope and traverses are taken right across the deposit sizing all the particles encountered.

Reference: K.R.May, Journal of Scientific Instruments Vol. 22 Oct 1945. 'The Cascade Impactor, An Instrument for Sampling Coarse Aerosols'.

Key Features

Eyepiece reticle designed to extend the sizing range of the globe & circle reticles

A series of concentric circles with Root 2 progression and divided square that can be used in conjunction with, for example, the NG2.