Drawing Number: 21113
Revision: A
OPERATION MANUAL FOR
ICP
®
HIGH PRESSURE SENSORS
Series 108 & 109
1
1.0
INTRODUCTION
The 108 & 109 Series are acceleration-compensated,
high pressure, ICP
®
(Integrated Circuit Piezoelectric)
sensors primarily developed to measure ballistics
chamber pressures for R & D and production testing
of ammunition. They may also be used for explosive
air blast and other high pressure measurements in
extreme shock environments where ultra-fast, micro-
second response is required. These types of tests are
usually accompanied by large acceleration pulses,
which can add considerable error to output signals of
un-compensated sensors.
The shoulder seal design features a one-piece
diaphragm machined integral with the housing for
ruggedness. A ceramic coating is applied to the
diaphragm to minimize flash temperature effects.
For applications where strain sensitivity from stress
within the mounting port is a concern, the 108A1X,
108B1X, 109B1X and 109C1X utilize a floating
clamp-nut design to reduce the effects, where “X”
denotes pressure range.
2.0
DESCRIPTION
The 108 & 109 Series contain an acceleration-
compensated piezo element, which is coupled to a
microelectronic amplifier. The quartz element
contains an integral seismic mass that counteracts the
acceleration effects of the end piece and diaphragm.
This compensation acts to extend the frequency
characteristics and enhance the transient response of
the sensor.
The machined diaphragm is made from maraging
steel, selected because of its high strength and
durability. The combination of the short, rigid
element and stiff diaphragm give these sensors a high
natural frequency and linearity.
The microelectronic amplifier converts the high-
impedance voltage from the quartz package into a
low-impedance, high-level output signal. See the
Technical Information section of our website for
more complete coverage of ICP
®
instruments.
3.0
INSTALLATION
With a 3/8-24 (M10x1.0 for metric mount) mounting
thread and flush diaphragm design, the 108 & 109
Series transducers mount directly in existing ports
machined for PCB Series 118 & 119.
Unlike conventional diaphragm type sensors, the 108
& 109 Series are pressure sensitive over the entire
frontal area. Extra care should be exercised to avoid
bottoming in the mounting hole when recess mounted
or when mounting into existing ports.
Install the sensor, using only one of the seals
provided, with the aid of a torque wrench to monitor
the mounting torque value. The recommended torque
range can be found on the installation drawing. Seals
should be replaced each time the sensor is re-
installed.
3.1
MOUNTING IN EXISTING
RECESSED PORTS
Before installing the sensor in previously used
mounting ports, clean out the residue from previous
tests. The port can be cleaned by hand reaming the ¼
inch diameter hole using a PCB Model 040A end
cutting reamer (040A07 for metric mount) guided by
PCB Model 041A pilot bushing (M041A for metric
mount).
Pay particular attention to the sealing surface,
keeping it free from tool chatter marks, nicks and
other imperfections that could adversely affect the
seal. If the sealing surface requires re-machining
after prolonged use, refer to the installation drawing
to ensure that the ¼ inch hole is deepened to avoid
bottoming of the sensor when re-installed.
10-32 COAXIAL
CONNECTOR
5/16 HEX
3/8-24 THREAD
QUARTZ ELEMENT
CERAMIC COATING
ICP
®
AMPLIFIER