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Q: Can I use a Sensorex ORP electrode with any
meter or controller ?
A: Yes. The
output signal of all ORP electrodes are compatible with virtually
all meters and controllers. When ordering, please specify the type
of connector, the length of cable, and the installation configuration
(if installing in a tank, pipe tee, or insertion.). You can even
read ORP output with most DVM's (digital volt meter).
Q: What is the range of ORP (units of measure)?
A: ORP is expressed
in millivolts (mV). A range of -1000 mV to 1000mV is common
with most ORP instruments.
Q: What does ORP really measure?
A: ORP measures
the total activity of a solution in mV or the total of reducing
and oxidizing activities in a given solution. Practically
speaking, ORP is useful for monitoring and controlling chemical
addition of oxidizing or reducing agents. Oxidizing agents
include chlorine, bromine and ozone. Reducing agents include
cyanide and sodium bisulfite and metabisulfite.
Q:
How does an ORP electrode work?
A: An ORP electrode
employs a nobel metal such as Platinum to sense electron transfer
in oxidizing and reducing reactions. ORP senses the total
electron transfer, or more simply if a chemical mix has more oxidizers
than reducers in it. Nobel metals such as Platinum, Silver
or Gold are use because they can sense the electron transfer but
are not consumed in the reactions.
Q: What are some common ORP applications?
A:
- Control of chlorine addition in swimming pools
- Fruit and Poultry washing (disinfection)
- Cyanide destruction in plating
- Hexavalent chromium reduction
- Mining application,
- Control/monitoring of ozone addition in swimming pools and aquariums
or purification of water prior to bottling or use in sterile solutions.
- Bromine addition for disinfection of pools and spas is also
common.
Q: How is ORP calibrated?
A: ORP does not
have to be "calibrated" but it can be tested if desired
or required. Standard ORP Test Solutions with stable mV outputs
are required. Two types of solutions are available.
One type requires you to mix pH buffers 4 and 7 with
quinhydrone. These offer 2 different stable values, but the
shelf life is only several hours and they cannot be stored.
Sensorex part number B125 is a complete kit with everything that
you need to complete 2 point testing.
A second type of premixed solution is also available.
Sensorex offers 2 of these for your analytical testing pleasure.
B225 has a stable output of 230 mV, and B425 has a stable output
of 450 mV. Shelf life of these solutions is guaranteed
for 12 months. Please see ORP
Accessories for a complete description and and how to
purchase from Sensorex. |
