Model 420 & 425 Flame Photometer
425 91 001
Issue 22
1
st
December 2016
ECN 1410 & 1932
- 48 -
Operating Hints, Precautions and Limitations
continued
7.3
Hazards
1.
All electrical instruments are potentially hazardous. With the exception of the
glass chimney, there are no user-maintainable parts inside the Model
420/425 covers. Never remove covers from the instrument, unless specific
maintenance instructions are being followed.
2.
Propane and Butane are highly inflammable and potentially explosive gases.
Propane and Butane are stored as a liquid, under pressure in a cylinder, for
use with the instrument. Such a cylinder should never be subjected to heat or
mechanical shock. When handled correctly and connected to the instrument
as instructed, the fuel gas is quite safe. Check hosing joints with a soap
solution before allowing any naked flame in the vicinity. Never open a
cylinder valve to the atmosphere even on a supposedly empty cylinder.
3.
The chimney cap and glass chimney and the area above the chimney
can become very hot and are capable of causing severe burns. Never
view the flame from the top of the chimney, always use the inspection
hole.
4.
Make sure that the air compressor is connected to the power supply and
switched on before starting a flame ignition sequence. If this is not done the
instrument will not light, as there is a safety cut out which detects the air
pressure. If there is no air pressure, error code ‘E61’ will be displayed ‘No
Flame’.
7.4
Measuring Calcium
The Model 425 has the additional channel for Calcium, which has been
requested by many customers.
It should be noted however that because the Model 425 uses propane /air
flame there is not sufficient energy to break the calcium phosphate bond
which may occur within, particularly, clinical samples. In these samples, a
pre-treatment protocol must be used. Sherwood has a method on our
website:
www.sherwood-scientific.com/apps/f003m.html
With other calcium samples, chelation with EDTA or extraction with Mehling’s
3 solution may be indicated.