Tube Liquid Sensor
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The OPB350 series liquid sensor is designed to work with 1/16” [1.6mm], 1/8” [3.2mm], 3/16” [4.8mm] and 1/4” [6.3mm] outside diameter clear tubes. When output reference circuitry is added, multiple output states such as “fluid present,” “no fluid present” and “no tube present” can be recognized. |
Clear liquid present causes the phototransistor
to sink to the maximum current, while dark liquid
present causes it to sink to the minimum current.
As bubbles pass through the tube, the signal will
vary between the “liquid present” and “no liquid”
states. If no tube is present, the phototransistor
sinks current between the dark fluid and clear
fluid states. The customer will have to identify the
typical current values for each situation. The ratio
between the different states allows acknowledgement
of different conditions.
Smaller outside diameter tubes can be used when
the tube is sized up to one of the standard sizes
and is fitted properly in the housing opening. For
example, fluid in a 1/32” [0.8mm] outside diameter
tube can be sensed when a piece of tubing
with a 1/8” [3.2mm] outside diameter and a 1/32”
[0.8mm] inside diameter is used as an adapter.
FEATURES
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- Can identify if liquid is present in clear tubes that have an outside diameter of 1/16” [1.6mm], 1/8” [3.2mm], 3/16” [4.8mm] or 1/4” [6.3mm]
- Opaque plastic housing enhances ambient light rejection
- Printed circuit board mounting or 24” [610mm] 26 AWG wires
- Custom tube sizes of sensors are possible
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APPLICATIONS
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- Non-contact fluid sensing
- IV fluid
- Oils and other petroleum products
- Colored fluids
- Toner fluids
- Water
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"T" Package
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"N" Package
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Fluid and Bubble Sensing for Medical Applications
Hemodialysis is the most common
method used to treat advanced and
permanent kidney failure. In hemodialysis,
the patient’s blood is allowed to flow through
a machine with a special filter that removes
wastes and extra fluids. The clean blood is
then returned to the patient’s bloodstream.
Hemodialysis Equipment Requirements
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The hemodialysis instrument has three main jobs:
pump blood and monitor blood flow for safety,
clean wastes from blood and monitor blood pressure
and rate of fluid removal from the patient’s
body. An air and/or bubble sensor checks the
blood in the tubing to ensure that air does not get
into the bloodstream. The same type of sensor can
be use to detect the presence or absence of other
fluids in the machine, like purified water and dialysate
fluid.
There are several non-invasive means to identify
if a tube containing fluid has an air bubble in it.
We can just post a person to watch it or we can
use an electronic means of identifying the change
in viscosity or transmission of the fluid within the
tube. The two most common ways in the industry
to identify the presence of a fluid or bubble are “Ultrasonic”
and “Optoelectronic.”
Using optoelectronics, the user can identify the
presence of the tube, presence of a bubble and in
some cases, the type of fluid being evaluated in
the tube.
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Figure 1.
As can be seen in Figure 1, when monitoring
the output of the phototransistor across a
resistor, a voltage can be used to identify
output levels utilizing a
microprocessor or comparator
circuit. The states that can be
identified are: presence of a tube,
air in the tube, saline solution
or some Hematocrit levels.
With the ability to vary the current
drive on the LED, or change
the sensitivity of the measurement
techniques, critical measurements
of minor optical transmission
characteristics of the fluid can
be used to identify different fluids
such as Hematocrit percentage.
Featured Products
| Part Number |
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Description |
Data
Sheet |
App.
Notes |
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| OPB350 |
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Fluid In-line Sensor
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| OPB350L062 |
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Fluid Sensor, 0.062" Tubing
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| OPB350L187 |
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Fluid In-line Sensor, .187D, Solder Leads
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| OPB350L250 |
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Fluid In-line Sensor, .250D, Solder Leads
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| OPB350W062Z |
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Fluid Sensor, 0.062" Tubing
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| OPB350W187Z |
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Fluid In-line Sensor, .187D, Wire Leads
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| OPB350W250Z |
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Fluid In-line Sensor, .250D, Wire Leads
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refers to New Product Introduction
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