What is the shelf life of your pH sensors?
All pH sensors from M4 Knick come with a minimum 2-year shelf life.
How often is calibration required with your pH sensors?
Calibration frequency depends on the application conditions (temperature, pH range, suspended solids) and the user's preferred maintenance practices. Implementing the correct sensor type for the application will also reduce calibration frequency.
The Portavo portable meter produces more reliable calibration results for offline calibration of Memosens smart digital sensors.
How long will your pH sensor last in my process?
The specific application affects sensor longevity. It is important for the user to use the correct sensor for the application. In addition, Memosens smart digital technology provides sensor diagnostics to technicians. The information provides sensor conditions and suggests if sensors should be serviced or replaced.
Does M4 Knick offer a non-glass pH sensor?
Yes, M4 Knick offers pH sensors that are non-glass. An
ISFET pH sensor made of FDA-compliant PEEK as well as a line of Glasteel™ sensors manufactured with a rugged enamel material.
Are your pH sensors temperature compensated?
Yes, most pH sensors from M4 Knick come with an integrated temperature detector for automatic compensation of the pH measurement. There are analog sensors in our product range that are available without integrated temperature compensation.
How do I calibrate pH sensors from M4 Knick?
You can calibrate M4 Knick pH sensors in several ways.
You can utilize the traditional method of calibrating a sensor with a field-mounted transmitter. You can also take advantage of the ability to calibrate offline, when using Memosens smart digital sensors, by using either our
Portavo portable meters or our
Memosuite sensor management software.
How do our sensors handle buildup?
Buildup on any pH sensor over time can impact the measurement. M4 Knick has sensors with specific junction/diaphragm and reference designs to provide stable measurements even with some buildup. We also have multiple options for integrated cleaning of the sensor within our holders and flow cells.
Can you install a pH sensor from M4 Knick upside down?
It is recommended that users mount glass pH sensors sensor at least 15°above horizontal. Some of our
Glasteel™ sensors and
ISFET sensor are mountable in any orientation, including upside down.
Do you have a retractable holder for any of your conductivity sensors?
The
SE 615 conductivity sensor will work with all M4 Knick retractable holders.
What is a cell constant?
The ratio of the distance (d) between conductivity sensor electrodes to the area (a) of the electrodes.
K = d/a
K = cell constant (cm-1)
a = effective area of the electrodes (cm2)
d = distance between the electrodes (cm)
Adjustment of the cell constant is a method for calibrating a conductivity loop to a known conductivity value.
How do you calibrate a conductivity sensor?
Conductivity sensors are calibrated using a single known value as a standard (one point calibration). An accurate process sample or known calibration standard can be used.
What is the difference between resistivity and conductivity?
Resistivity is a measure of a material's tendency to resist the flow of electrical current. Conductivity is a measure of a material's tendency to allow the flow of electrical current when a potential difference is put across it. Conductivity is the reciprocal of resistivity.
Does a conductivity measurement need to be temperature compensated?
Yes, a known temperature value is required in order to make an accurate conductivity measurement. Most conductivity sensors include temperature measurement.
Can a conductivity sensor be used for concentration measurement?
Yes, conductivity sensors can be used for measuring the concentration of many acids and bases. M4 Knick transmitters, with the exception of
MemoRail, are pre-programmed with 11 concentration curves and are able to display these values.
What is inductive (toroidal) conductivity?
Inductive conductivity is sometimes called toroidal conductivity. An inductive sensor consists of two wire-wound metal toroids encased in a corrosion-resistant plastic body. One toroid is the drive coil, the other is the receive coil. The sensor is immersed in the conductive liquid. The analyzer/transmitter applies an alternating voltage to the drive coil, which induces a voltage in the liquid surrounding the coil. The voltage causes an ionic current to flow proportional to the conductance of the liquid. The ionic current induces an electronic current in the receive coil, which the analyzer/transmitter measures. The induced current is directly proportional to the conductance of the solution.
Can we measure total dissolved solids?
Yes, but only with the
Portavo portable meters.
Can we measure salinity?
Yes, our transmitters/analyzers can be programmed to read % salinity in g/kg. Salinity is the concentration of dissolved salts in water.
What is the lowest conductivity value we can read?
The
SE 604 and
SE 605 are capable of reading conductivity values as low as 1 nS/cm.
What is our maximum temperature specification?
The
SE 600 4-electrode sensor can operate up to 410ºF.
What is our maximum pressure specification?
The
SE 600 4-electrode sensor and
SE 605 2-electrode sensor can operate up to 362 psi.
How do we handle buildup?
Inductive (toroidal) sensors are recommended for applications with high-suspended solids and the potential for buildup.
Where are ORP measurements used?
ORP measurements are often used to monitor the destruction of contaminants in many processes. Common applications are chlorine control in cooling towers, aeration control in wastewater, destruction of cyanide in metals and mining, and complete removal of harmful chemicals through wet gas scrubbing.
What is ORP?
ORP or oxidation-reduction potential is the measurement of the ability of a chemical substance to either oxidize or reduce another chemical substance. The measurement is made in mV (millivolts) with oxidizers having a positive (+) ORP value and reducers having a negative (-) ORP value.
Are ORP and Redox the same?
Yes, both terms are interchangeable and refer to the same measurement. ORP stands for Oxidation Reduction Potential while Redox stands for reduction/oxidation.
Does M4 Knick offer a sensor that measures both pH and ORP?
Yes, many ORP applications also have a pH measurement incorporated. M4 Knick offers two sensors that provide simultaneous pH and ORP measurements from one electrode. The
SE 554 AMSN and
PL-PETR provide both cost and space savings.
How do I calibrate my ORP sensor?
ORP sensors calibrating using a known standard (example: 220 mV REDOX Buffer) or validated process value. Immerse the sensor in the standard and adjusts the displayed value.
Are ORP measurements temperature compensated?
No, temperature affects ORP measurements but they are NOT corrected for it. An ORP value simply reflects the ability of whatever is in the water to oxidize whatever contaminants are in the water.
