G22 eyepiece reticles, Walton/Beckett for asbestos

Walton and Beckett Graticule for AsbestosCalibration factors are required for each of these graticules. See note below.The Walton and Beckett graticule is used for counting fibrous dust (e.g. asbestos or glass fibres) and is particularly useful where the majority of fibres to be counted are shorter than 5 microns. The circle is divided into four by two diametrical lines scaled in units of 5 and 3 microns respectively. 3 and 5 microns are the critical measurements of fibre lengths and diameters used in fibre counting. Unlike the usual globes of other particle graticules, the Walton and Beckett have a series of shapes to compare objects with. These shapes have been designed for comparison with fibres, especially since they incorporate an aspect ratio of 3:1 or 5:1, essential for such analysis.PatternDescriptionDiameter

Walton and Beckett Graticule for Asbestos

Calibration factors are required for each of these graticules. See note below.

The Walton and Beckett graticule is used for counting fibrous dust (e.g. asbestos or glass fibres) and is particularly useful where the majority of fibres to be counted are shorter than 5 microns. The circle is divided into four by two diametrical lines scaled in units of 5 and 3 microns respectively. 3 and 5 microns are the critical measurements of fibre lengths and diameters used in fibre counting. Unlike the usual globes of other particle graticules, the Walton and Beckett have a series of shapes to compare objects with. These shapes have been designed for comparison with fibres, especially since they incorporate an aspect ratio of 3:1 or 5:1, essential for such analysis.

Pattern	Description	Diameter	Code
G22	Walton & Beckett for asbestos, 3:1 ratio. Glass sandwich.	16mm	EMS68028-16
		19mm	EMS68028-19
		20.4mm	EMS68028-20.4
		21mm	EMS68028-21
		23mm	EMS68028-23
		24.5mm	EMS68028-24.5
		25mm	EMS68028-25
		26mm	EMS68028-26
		27mm	EMS68028-27
G24	Walton & Beckett for asbestos, 5:1 ratio. Glass sandwich.	16mm	EMS68029-16
		19mm	EMS68029-19
		21mm	EMS68029-21
G25	Based on the G22, the G25 is produced by the Institute of Occupational Health (1996). Glass sandwich.	16mm	EMS68030-16
		19mm	EMS68030-19
		21mm	EMS68030-21

Important Note: The circle on these Walton & Beckett graticules must represent 100 microns at the stage and each one must be manufactured to suit the individual instrument.

Therefore, the following details should be provided with your order:

1. Calibration factor, if known
2. Objective magnification
3. Eyepiece magnification
4. Diameter of graticule disc required
5. Microscope make and model